2024-03-29T10:34:24Zhttp://repository.helmholtz-hzi.de/oai/requestoai:repository.helmholtz-hzi.de:10033/84012019-08-30T11:32:37Zcom_10033_6805com_10033_6799col_10033_6880
Zyxin Is not Colocalized with Vasodilator-stimulated Phosphoprotein (VASP) at Lamellipodial Tips and Exhibits Different Dynamics to Vinculin, Paxillin, and VASP in Focal AdhesionsV⃞
Rottner, Klemens
Krause, Matthias
Gimona, Mario
Small, J. Victor
Wehland, Jürgen
Beckerle, Mary C.
2007-02-14T15:43:39Z
2001-10
2007-02-14T15:43:39Z
2001-10
Molecular Biology of the Cell 2001 12(10):3103-3113
1059-1524
11598195
http://hdl.handle.net/10033/8401
60159
en_US
Copyright © 2001, The American Society for Cell Biology
The American Society for Cell Biology
oai:repository.helmholtz-hzi.de:10033/84072019-08-30T11:32:14Zcom_10033_6802com_10033_6799col_10033_6873
Achieving 100% Typeability of Pseudomonas aeruginosa by Pulsed-Field Gel Electrophoresis
Römling, Ute
Tümmler, Burkhard
2007-02-14T15:49:01Z
2000-01
2007-02-14T15:49:01Z
2000-01
Journal of Clinical Microbiology 2000 38(1):464-465
0095-1137
1098-660X
10618146
http://hdl.handle.net/10033/8407
88754
en_US
Copyright © 2000, American Society for Microbiology
American Society for Microbiology
oai:repository.helmholtz-hzi.de:10033/85012019-08-30T11:32:38Zcom_10033_6802com_10033_6799col_10033_6873
Contribution of Ena/VASP Proteins to Intracellular Motility of Listeria Requires Phosphorylation and Proline-rich Core but Not F-Actin Binding or Multimerization
Geese, Marcus
Loureiro, Joseph J.
Bear, James E.
Wehland, Jürgen
Gertler, Frank B.
Sechi, Antonio S.
Drubin, David
2007-02-19T08:51:08Z
2002-07
2007-02-19T08:51:08Z
2002-07
Molecular Biology of the Cell 2002 13(7):2383-2396
1059-1524
12134077
10.1091/mbc.E02-01-0058
http://hdl.handle.net/10033/8501
117321
en_US
Copyright © 2002, The American Society for Cell Biology
The American Society for Cell Biology
oai:repository.helmholtz-hzi.de:10033/85982019-08-30T11:32:38Zcom_10033_6800com_10033_6799col_10033_6875
In Vivo Effects of a Synthetic 2-Kilodalton Macrophage-Activating Lipopeptide of Mycoplasma fermentans after Pulmonary Application
Lührmann, Anke
Deiters, Ursula
Skokowa, Julia
Hanke, Michaela
Gessner, Johannes E.
Mühlradt, Peter F.
Pabst, Reinhard
Tschernig, Thomas
2007-02-20T12:50:48Z
2002-07
2007-02-20T12:50:48Z
2002-07
Infection and Immunity 2002 70(7):3785-3792
0019-9567
1098-5522
12065522
10.1128/IAI.70.7.3785-3792.2002
http://hdl.handle.net/10033/8598
128036
en_US
Copyright © 2002, American Society for Microbiology
American Society for Microbiology
oai:repository.helmholtz-hzi.de:10033/86172019-08-30T11:32:39Zcom_10033_6804com_10033_6799col_10033_6883
Telomere shortening impairs organ regeneration by inhibiting cell cycle re-entry of a subpopulation of cells
Satyanarayana, A.
Wiemann, S.U.
Buer, J.
Lauber, J.
Dittmar, K.E.J.
Wüstefeld, T.
Blasco, M.A.
Manns, M.P.
Rudolph, K.L.
2007-02-20T13:12:00Z
2003-08-01
2007-02-20T13:12:00Z
2003-08-01
The EMBO Journal 2003 22(15):4003-4013
0261-4189
1460-2075
12881434
10.1093/emboj/cdg367
http://hdl.handle.net/10033/8617
169040
en_US
http://www.emboj.oupjournals.org/content/vol22/issue15/
Copyright © 2003 European Molecular Biology Organization
Oxford University Press
oai:repository.helmholtz-hzi.de:10033/85282019-08-30T11:32:39Zcom_10033_6802com_10033_6799col_10033_6873
Expression of the Listeria monocytogenes EGD inlA and inlB genes, whose products mediate bacterial entry into tissue culture cell lines, by PrfA-dependent and -independent mechanisms.
Lingnau, A
Domann, E
Hudel, M
Bock, M
Nichterlein, T
Wehland, J
Chakraborty, T
2007-02-19T10:32:36Z
1995-10
2007-02-19T10:32:36Z
1995-10
Infection and Immunity 1995 63(10):3896-3903
0019-9567
1098-5522
7558297
http://hdl.handle.net/10033/8528
173548
en_US
oai:repository.helmholtz-hzi.de:10033/85292019-08-30T11:32:39Zcom_10033_6802com_10033_6799col_10033_6873
Identification and purification of novel internalin-related proteins in Listeria monocytogenes and Listeria ivanovii.
Lingnau, A
Chakraborty, T
Niebuhr, K
Domann, E
Wehland, J
2007-02-19T10:34:26Z
1996-03
2007-02-19T10:34:26Z
1996-03
Infection and Immunity 1996 64(3):1002-1006
0019-9567
1098-5522
8641748
http://hdl.handle.net/10033/8529
173869
en_US
oai:repository.helmholtz-hzi.de:10033/85302019-08-30T11:32:39Zcom_10033_6802com_10033_6799col_10033_6873
The ActA polypeptides of Listeria ivanovii and Listeria monocytogenes harbor related binding sites for host microfilament proteins.
Gerstel, B
Gröbe, L
Pistor, S
Chakraborty, T
Wehland, J
2007-02-19T10:35:30Z
1996-06
2007-02-19T10:35:30Z
1996-06
Infection and Immunity 1996 64(6):1929-1936
0019-9567
1098-5522
8675289
http://hdl.handle.net/10033/8530
174018
en_US
oai:repository.helmholtz-hzi.de:10033/86132019-08-30T11:25:04Zcom_10033_6800com_10033_6799col_10033_6875
Involvement of interleukin-1 (IL-1), IL-6, IL-2, and IL-4 in generation of cytolytic T cells from thymocytes stimulated by a Mycoplasma fermentans-derived product.
Mühlradt, P F
Quentmeier, H
Schmitt, E
2007-02-20T13:09:16Z
1991-11
2007-02-20T13:09:16Z
1991-11
Infection and Immunity 1991 59(11):3962-3968
0019-9567
1098-5522
1937754
http://hdl.handle.net/10033/8613
258983
en_US
oai:repository.helmholtz-hzi.de:10033/86152019-08-30T11:25:04Zcom_10033_6800com_10033_6799col_10033_6875
MDHM, a macrophage-stimulatory product of Mycoplasma fermentans, leads to in vitro interleukin-1 (IL-1), IL-6, tumor necrosis factor, and prostaglandin production and is pyrogenic in rabbits.
Mühlradt, P F
Schade, U
2007-02-20T13:10:30Z
1991-11
2007-02-20T13:10:30Z
1991-11
Infection and Immunity 1991 59(11):3969-3974
0019-9567
1098-5522
1937755
http://hdl.handle.net/10033/8615
258984
en_US
oai:repository.helmholtz-hzi.de:10033/86272019-08-30T11:26:12Zcom_10033_6800com_10033_6799col_10033_6875
Purification and partial biochemical characterization of a Mycoplasma fermentans-derived substance that activates macrophages to release nitric oxide, tumor necrosis factor, and interleukin-6.
Mühlradt, P F
Frisch, M
Images
2007-02-20T13:25:21Z
1994-09
2007-02-20T13:25:21Z
1994-09
Infection and Immunity 1994 62(9):3801-3807
0019-9567
1098-5522
8063396
http://hdl.handle.net/10033/8627
303034
en_US
oai:repository.helmholtz-hzi.de:10033/86422019-08-30T11:25:04Zcom_10033_6800com_10033_6799col_10033_6875
Mycoplasma fermentans-derived high-molecular-weight material induces interleukin-6 release in cultures of murine macrophages and human monocytes.
Quentmeier, H
Schmitt, E
Kirchhoff, H
Grote, W
Mühlradt, P F
2007-02-20T13:36:12Z
1990-05
2007-02-20T13:36:12Z
1990-05
Infection and Immunity 1990 58(5):1273-1280
0019-9567
1098-5522
2323816
http://hdl.handle.net/10033/8642
258620
en_US
oai:repository.helmholtz-hzi.de:10033/86432019-08-30T11:24:25Zcom_10033_6800com_10033_6799col_10033_6875
Effects of pyocyanine, a phenazine dye from Pseudomonas aeruginosa, on oxidative burst and bacterial killing in human neutrophils.
Müller, P K
Krohn, K
Mühlradt, P F
2007-02-20T13:36:37Z
1989-09
2007-02-20T13:36:37Z
1989-09
Infection and Immunity 1989 57(9):2591-2596
0019-9567
1098-5522
2547716
http://hdl.handle.net/10033/8643
313499
en_US
oai:repository.helmholtz-hzi.de:10033/86462019-08-30T11:25:38Zcom_10033_6800com_10033_6799col_10033_6875
The p53-dependent effects of macrophage migration inhibitory factor revealed by gene targeting
Fingerle-Rowson, G.
Petrenko, O.
Metz, C. N.
Forsthuber, T. G.
Mitchell, R.
Huss, R.
Moll, U.
Müller, W.
Bucala, R.
2007-02-20T13:37:53Z
2003-08-05
2007-02-20T13:37:53Z
2003-08-05
Proceedings of the National Academy of Sciences of the United States of America 2003 100(16):9354-9359
0027-8424
1091-6490
12878730
10.1073/pnas.1533295100
http://hdl.handle.net/10033/8646
170922
en_US
Copyright © 2003, The National Academy of
Sciences
National Academy of Sciences
oai:repository.helmholtz-hzi.de:10033/86672019-08-30T11:27:08Zcom_10033_6804com_10033_6799col_10033_6883
Mitogen Stimulation Cooperates with Telomere Shortening To Activate DNA Damage Responses and Senescence Signaling
Satyanarayana, A.
Greenberg, R. A.
Schaetzlein, S.
Buer, J.
Masutomi, K.
Hahn, W. C.
Zimmermann, S.
Martens, U.
Manns, M. P.
Rudolph, K. L.
2007-02-20T14:38:00Z
2004-06
2007-02-20T14:38:00Z
2004-06
Molecular and Cellular Biology 2004 24(12):5459-5474
0270-7306
1098-5549
15169907
10.1128/MCB.24.12.5459-5474.2004
http://hdl.handle.net/10033/8667
419883
en_US
Copyright © 2004, American Society for Microbiology
American Society for Microbiology
oai:repository.helmholtz-hzi.de:10033/86802019-08-30T11:32:36Zcom_10033_6800com_10033_6799col_10033_6875
Pre-B cell receptor expression is necessary for thymic stromal lymphopoietin responsiveness in the bone marrow but not in the liver environment
Vosshenrich, Christian A. J.
Cumano, Ana
Müller, Werner
Di Santo, James P.
Vieira, Paulo
2007-02-21T08:16:20Z
2004-07-27
2007-02-21T08:16:20Z
2004-07-27
Proceedings of the National Academy of Sciences of the United States of America 2004 101(30):11070-11075
0027-8424
1091-6490
15263090
10.1073/pnas.0402919101
http://hdl.handle.net/10033/8680
503742
en_US
Copyright © 2004, The National Academy of Sciences
National Academy of Sciences
oai:repository.helmholtz-hzi.de:10033/86872019-08-30T11:24:26Zcom_10033_6802com_10033_6799col_10033_6873
Enzymes Involved in Anaerobic Respiration Appear To Play a Role in Actinobacillus pleuropneumoniae Virulence
Jacobsen, Ilse
Hennig-Pauka, Isabel
Baltes, Nina
Trost, Matthias
Gerlach, Gerald-F.
2007-02-21T08:25:47Z
2005-01
2007-02-21T08:25:47Z
2005-01
Infection and Immunity 2005 73(1):226-234
0019-9567
1098-5522
15618158
10.1128/IAI.73.1.226-234.2005
http://hdl.handle.net/10033/8687
538954
en_US
Copyright © 2005, American Society for Microbiology
American Society for Microbiology
oai:repository.helmholtz-hzi.de:10033/86922019-08-30T11:26:13Zcom_10033_6802com_10033_6799col_10033_6873
The ActA protein of Listeria monocytogenes acts as a nucleator inducing reorganization of the actin cytoskeleton.
Pistor, S
Chakraborty, T
Niebuhr, K
Domann, E
Wehland, J
Images
2007-02-21T08:29:56Z
1994-02-15
2007-02-21T08:29:56Z
1994-02-15
The EMBO Journal 1994 13(4):758-763
0261-4189
1460-2075
8112291
http://hdl.handle.net/10033/8692
394872
en_US
oai:repository.helmholtz-hzi.de:10033/86972019-08-30T11:24:27Zcom_10033_6804com_10033_6799col_10033_6883
Skp2-dependent degradation of p27kip1 is essential for cell cycle progression
Kossatz, Uta
Dietrich, Nils
Zender, Lars
Buer, Jan
Manns, Michael P
Malek, Nisar P.
2007-02-21T08:37:01Z
2004-11-01
2007-02-21T08:37:01Z
2004-11-01
Genes & Development 2004 18(21):2602-2607
0890-9369
15520280
10.1101/gad.321004
http://hdl.handle.net/10033/8697
525540
en_US
Copyright © 2004, Cold Spring Harbor Laboratory Press
Cold Spring Harbor Laboratory Press
oai:repository.helmholtz-hzi.de:10033/87052019-08-30T11:25:07Zcom_10033_6804com_10033_6799col_10033_6883
Common and Unique Gene Expression Signatures of Human Macrophages in Response to Four Strains of Mycobacterium avium That Differ in Their Growth and Persistence Characteristics
Blumenthal, Antje
Lauber, Jörg
Hoffmann, Reinhard
Ernst, Martin
Keller, Christine
Buer, Jan
Ehlers, Stefan
Reiling, Norbert
2007-02-21T08:45:00Z
2005-06
2007-02-21T08:45:00Z
2005-06
Infection and Immunity 2005 73(6):3330-3341
0019-9567
1098-5522
15908359
10.1128/IAI.73.6.3330-3341.2005
http://hdl.handle.net/10033/8705
1111816
en_US
Copyright © 2005, American Society for Microbiology
American Society for Microbiology
oai:repository.helmholtz-hzi.de:10033/87492019-08-30T11:25:09Zcom_10033_6802com_10033_6799col_10033_6873
Actin pedestal formation by enteropathogenic Escherichia coli and intracellular motility of Shigella flexneri are abolished in N-WASP-defective cells
Lommel, Silvia
Benesch, Stefanie
Rottner, Klemens
Franz, Thomas
Wehland, Jürgen
Kühn, Ralf
2007-02-22T14:46:22Z
2001-09-15
2007-02-22T14:46:22Z
2001-09-15
EMBO Reports 2001 2(9):850-857
1469-221X
1469-3178
11559594
10.1093/embo-reports/kve197
http://hdl.handle.net/10033/8749
1084051
en_US
http://www.embo-reports.oupjournals.org/content/vol2/issue9/
Copyright © 2001 European Molecular Biology Organization
Oxford University Press
oai:repository.helmholtz-hzi.de:10033/123682019-08-30T11:37:00Zcom_10033_6804com_10033_6799col_10033_6883
Identification of novel regulators in T-cell differentiation of aplastic anemia patients.
Franzke, Anke
Geffers, Robert
Hunger, J Katrin
Pförtner, Susanne
Piao, Wenji
Ivanyi, Philipp
Grosse, Jens
Probst-Kepper, Michael
Ganser, Arnold
Buer, Jan
BACKGROUND: Aplastic anemia (AA) is a bone marrow failure syndrome mostly characterized by an immune-mediated destruction of marrow hematopoietic progenitor/stem cells. The resulting hypocellularity limits a detailed analysis of the cellular immune response. To overcome this technical problem we performed a microarray analysis of CD3+ T-cells derived from bone marrow aspirates and peripheral blood samples of newly diagnosed AA patients and healthy volunteers. Two AA patients were additionally analyzed after achieving a partial remission following immunosuppression. The regulation of selected candidate genes was confirmed by real-time RT-PCR. RESULTS: Among more than 22,200 transcripts, 583 genes were differentially expressed in the bone marrow of AA patients compared to healthy controls. Dysregulated genes are involved in T-cell mediated cytotoxicity, immune response of Th1 differentiated T-cells, and major regulators of immune function. In hematological remission the expression levels of several candidate genes tend to normalize, such as immune regulators and genes involved in proinflammatory immune response. CONCLUSION: Our study suggests a pivotal role of Th1/Tc1 differentiated T-cells in immune-mediated marrow destruction of AA patients. Most importantly, immune regulatory genes could be identified, which are likely involved in the recovery of hematopoiesis and may help to design new therapeutic strategies in bone marrow failure syndromes.
2007-06-14T12:13:49Z
2007-06-14T12:13:49Z
2006
Article
BMC Genomics 2006, 7:263
1471-2164
17052335
10.1186/1471-2164-7-263
http://hdl.handle.net/10033/12368
en
oai:repository.helmholtz-hzi.de:10033/124012019-08-30T11:37:00Zcom_10033_6811com_10033_6799col_10033_6877
The biophysics of T lymphocyte activation in vitro and in vivo.
Reichardt, Peter
Gunzer, Matthias
T cell activation is crucial for the development of specific immune reactions. It requires physical contact between T cells and antigen-presenting cells (APC). Since these cells are initially located at distinct positions in the body, they have to migrate and find each other within secondary lymphoid organs. After encountering each other both cells have to maintain a close membrane contact sufficiently long to ensure successful signaling. Thus, there is the necessity to temporarily synchronize the motile behavior of these cells. Initially, it had been proposed that during antigen recognition, T cells receive a stop signal and maintain a stable contact with APC for several hours when an appropriate APC has been encountered. However, direct cell observation via time-lapse microscopy in vitro and in vivo has revealed a different picture. While long contacts can be observed, many interactions appear to be very short and sequential despite efficient signaling. Thus, two concepts addressing the biophysics of T cell activation have emerged. The single encounter model proposes that after a period of dynamic searching, a T cell stops to interact with one appropriately presenting APC until signaling is completed. The serial encounter model suggests that T cells are able to collect a series of short signals by different APC until a critical activation threshold is achieved. Future research needs to clarify the relative importance of short and dynamic versus long-lived T cell-APC encounters for the outcome of T cell activation. Furthermore, a thorough understanding of the molecular events underlying the observed complex motility patterns will make these phenomena amenable for intervention, which might result in the identification of new types of immune modulating drugs.
2007-06-20T10:45:50Z
2007-06-20T10:45:50Z
2006
Article
Results Probl Cell Differ 2006, 43:199-218
0080-1844
17068973
http://hdl.handle.net/10033/12401
en
oai:repository.helmholtz-hzi.de:10033/128552019-08-30T11:24:31Zcom_10033_6802com_10033_6799col_10033_6873
Evaluation of the E test for the assessment of synergy of antibiotic combinations against multiresistant Pseudomonas aeruginosa isolates from cystic fibrosis patients.
Balke, B
Hogardt, M
Schmoldt, S
Hoy, L
Weissbrodt, H
Häussler, S
The determination of synergistic effects of antimicrobial drug combinations can lead to improved therapeutic options in the antibiotic treatment of cystic fibrosis patients who are chronically infected with multiresistant Pseudomonas aeruginosa isolates. The aim of this study was to evaluate the performance of the E test versus the standard agar dilution checkerboard susceptibility test in the assessment of synergy and, in addition, to determine the activity of two antimicrobial combinations against 163 multiresistant P. aeruginosa isolates from cystic fibrosis patients. The agreement between the checkerboard method and the E test was excellent (>90%) for nonmucoid as well as mucoid isolates from cystic fibrosis patients. The rate of synergy was higher for the antibiotic combination of ceftazidime and tobramycin (28.8% of the cystic fibrosis strains) than for the combination of meropenem and tobramycin (19.0%). However, the probability of synergy for the second antibiotic combination increased significantly when the synergy of the first antibiotic combination had already been demonstrated (Fischer's exact test, p=0.049). The results show that the E test is a valuable and practical method for routine microbiological diagnostics and can aid in the selection of improved antibiotic options in the treatment of cystic fibrosis patients chronically infected with P. aeruginosa.
2007-07-23T09:22:59Z
2007-07-23T09:22:59Z
2006-01-01
Article
Eur. J. Clin. Microbiol. Infect. Dis. 2006, 25(1):25-30
0934-9723
16402226
10.1007/s10096-005-0076-9
http://hdl.handle.net/10033/12855
en
oai:repository.helmholtz-hzi.de:10033/128582019-08-30T11:24:31Zcom_10033_6804com_10033_6799col_10033_6883
CD8(+) T cells armed with retrovirally transduced IFN-gamma.
Becker, Christian
Lienenklaus, Stefan
Jablonska, Jadwiga
Bauer, Heike
Weiss, Siegfried
Interferon-gamma (IFN-gamma) is considered a key cytokine involved in the preventive and defensive responses of T cells against infectious pathogens and tumors. Therefore, the transgenic expression of IFN-gamma in specific T cells appears to be an obvious therapeutic possibility. To directly examine whether IFN-gamma production can be increased in T cells, we introduced an IFN-gamma encoding cDNA into IFN-gamma(-/-) and IFN-gamma(+/+) CD8(+) effector populations by retroviral transduction. Here, we show that CD8 T cells can be equipped with IFN-gamma that increases their capacity to secrete the cytokine. Despite constitutive retroviral IFN-gamma mRNA transcription, translation and secretion of IFN-gamma protein was tightly regulated and only observed in activated T cells. Neither proliferation nor cytolytic activity of CTL was affected by IFN-gamma transduction. Importantly, CD8(+) T cells retrovirally transduced with IFN-gamma exhibit augmented tumor suppressive capacity upon adoptive transfer into IFN-gamma(-/-) mice. Thus, T cells can be readily armed with IFN-gamma without risking immunopathology by dysregulated production of this highly potent proinflammatory cytokine.
2007-07-23T11:38:53Z
2007-07-23T11:38:53Z
2007-01-01
Article
J. Mol. Med. 2007, 85(1):63-73
0946-2716
17109130
10.1007/s00109-006-0107-8
http://hdl.handle.net/10033/12858
en
oai:repository.helmholtz-hzi.de:10033/129012019-08-30T11:33:29Zcom_10033_6802com_10033_6799col_10033_6873
Characterization of the Drosophila lipid droplet subproteome.
Beller, Mathias
Riedel, Dietmar
Jänsch, Lothar
Dieterich, Guido
Wehland, Jürgen
Jäckle, Herbert
Kühnlein, Ronald P
Lipid storage droplets are universal organelles essential for the cellular and organismal lipometabolism including energy homeostasis. Despite their apparently simple design they are proposed to participate in a growing number of cellular processes, raising the question to what extent the functional multifariousness is reflected by a complex organellar proteome composition. Here we present 248 proteins identified in a subproteome analysis using lipid storage droplets of Drosophila melanogaster fat body tissue. In addition to previously known lipid droplet-associated PAT (Perilipin, ADRP, and TIP47) domain proteins and homologues of several mammalian lipid droplet proteins, this study identified a number of proteins of diverse biological function, including intracellular trafficking supportive of the dynamic and multifaceted character of these organelles. We performed intracellular localization studies on selected newly identified subproteome members both in tissue culture cells and in fat body cells directly. The results suggest that the lipid droplets of fat body cells are of combinatorial protein composition. We propose that subsets of lipid droplets within single cells are characterized by a protein "zip code," which reflects functional differences or specific metabolic states.
2007-07-23T14:10:28Z
2007-07-23T14:10:28Z
2006-06-01
Article
Mol. Cell Proteomics 2006, 5(6):1082-94
1535-9476
16543254
10.1074/mcp.M600011-MCP200
http://hdl.handle.net/10033/12901
en
oai:repository.helmholtz-hzi.de:10033/137822019-08-30T11:34:48Zcom_10033_6802com_10033_6799col_10033_6873
Tubulin tyrosination is a major factor affecting the recruitment of CAP-Gly proteins at microtubule plus ends.
Peris, Leticia
Thery, Manuel
Fauré, Julien
Saoudi, Yasmina
Lafanechère, Laurence
Chilton, John K
Gordon-Weeks, Phillip
Galjart, Niels
Bornens, Michel
Wordeman, Linda
Wehland, Juergen
Andrieux, Annie
Job, Didier
Tubulin-tyrosine ligase (TTL), the enzyme that catalyzes the addition of a C-terminal tyrosine residue to alpha-tubulin in the tubulin tyrosination cycle, is involved in tumor progression and has a vital role in neuronal organization. We show that in mammalian fibroblasts, cytoplasmic linker protein (CLIP) 170 and other microtubule plus-end tracking proteins comprising a cytoskeleton-associated protein glycine-rich (CAP-Gly) microtubule binding domain such as CLIP-115 and p150 Glued, localize to the ends of tyrosinated microtubules but not to the ends of detyrosinated microtubules. In vitro, the head domains of CLIP-170 and of p150 Glued bind more efficiently to tyrosinated microtubules than to detyrosinated polymers. In TTL-null fibroblasts, tubulin detyrosination and CAP-Gly protein mislocalization correlate with defects in both spindle positioning during mitosis and cell morphology during interphase. These results indicate that tubulin tyrosination regulates microtubule interactions with CAP-Gly microtubule plus-end tracking proteins and provide explanations for the involvement of TTL in tumor progression and in neuronal organization.
2007-09-25T08:25:17Z
2007-09-25T08:25:17Z
2006-09-11
Article
J. Cell Biol. 2006, 174(6):839-49
0021-9525
16954346
10.1083/jcb.200512058
http://hdl.handle.net/10033/13782
en
oai:repository.helmholtz-hzi.de:10033/145442019-08-30T11:33:57Zcom_10033_6804com_10033_6799col_10033_6883
Signatures of human regulatory T cells: an encounter with old friends and new players.
Pfoertner, Susanne
Jeron, Andreas
Probst-Kepper, Michael
Guzman, Carlos A
Hansen, Wiebke
Westendorf, Astrid M
Toepfer, Tanja
Schrader, Andres J
Franzke, Anke
Buer, Jan
Geffers, Robert
BACKGROUND: Naturally occurring CD4+ CD25+ regulatory T cells (TReg) are involved in the control of autoimmune diseases, transplantation tolerance, and anti-tumor immunity. Thus far, genomic studies on TReg cells were restricted to murine systems, and requirements for their development, maintenance, and mode of action in humans are poorly defined. RESULTS: To improve characterization of human TReg cells, we compiled a unique microarray consisting of 350 TReg cell associated genes (Human TReg Chip) based on whole genome transcription data from human and mouse TReg cells. TReg cell specific gene signatures were created from 11 individual healthy donors. Statistical analysis identified 62 genes differentially expressed in TReg cells, emphasizing some cross-species differences between mice and humans. Among them, several 'old friends' (including FOXP3, CTLA4, and CCR7) that are known to be involved in TReg cell function were recovered. Strikingly, the vast majority of genes identified had not previously been associated with human TReg cells (including LGALS3, TIAF1, and TRAF1). Most of these 'new players' however, have been described in the pathogenesis of autoimmunity. Real-time RT-PCR of selected genes validated our microarray results. Pathway analysis was applied to extract signaling modules underlying human TReg cell function. CONCLUSION: The comprehensive set of genes reported here provides a defined starting point to unravel the unique characteristics of human TReg cells. The Human TReg Chip constructed and validated here is available to the scientific community and is a useful tool with which to study the molecular mechanisms that orchestrate TReg cells under physiologic and diseased conditions.
2007-11-13T12:06:04Z
2007-11-13T12:06:04Z
2006
Article
Genome Biol. 2006, 7(7):R54
1465-6914
16836768
10.1186/gb-2006-7-7-r54
http://hdl.handle.net/10033/14544
en
oai:repository.helmholtz-hzi.de:10033/141222019-08-30T11:33:57Zcom_10033_6807com_10033_6799col_10033_6884
Filopodia formation in the absence of functional WAVE- and Arp2/3-complexes.
Steffen, Anika
Faix, Jan
Resch, Guenter P
Linkner, Joern
Wehland, Juergen
Small, J Victor
Rottner, Klemens
Stradal, Theresia E B
Cell migration is initiated by plasma membrane protrusions, in the form of lamellipodia and filopodia. The latter rod-like projections may exert sensory functions and are found in organisms as distant in evolution as mammals and amoeba such as Dictyostelium discoideum. In mammals, lamellipodia protrusion downstream of the small GTPase Rac1 requires a multimeric protein assembly, the WAVE-complex, which activates Arp2/3-mediated actin filament nucleation and actin network assembly. A current model of filopodia formation postulates that these structures arise from a dendritic network of lamellipodial actin filaments by selective elongation and bundling. Here, we have analyzed filopodia formation in mammalian cells abrogated in expression of essential components of the lamellipodial actin polymerization machinery. Cells depleted of the WAVE-complex component Nck-associated protein 1 (Nap1), and, in consequence, of lamellipodia, exhibited normal filopodia protrusion. Likewise, the Arp2/3-complex, which is essential for lamellipodia protrusion, is dispensable for filopodia formation. Moreover, genetic disruption of nap1 or the WAVE-orthologue suppressor of cAMP receptor (scar) in Dictyostelium was also ineffective in preventing filopodia protrusion. These data suggest that the molecular mechanism of filopodia formation is conserved throughout evolution from Dictyostelium to mammals and show that lamellipodia and filopodia formation are functionally separable.
2007-10-17T11:25:31Z
2007-10-17T11:25:31Z
2006-06-01
Article
Mol. Biol. Cell 2006, 17(6):2581-91
1059-1524
16597702
10.1091/mbc.E05-11-1088
http://hdl.handle.net/10033/14122
en
oai:repository.helmholtz-hzi.de:10033/145462019-08-30T11:34:22Zcom_10033_6804com_10033_6799col_10033_6883
Multiple synergizing factors contribute to the strength of the CD8+ T cell response against listeriolysin O.
Bruder, Dunja
Nussbaum, Alexander K
Gakamsky, Dimitry M
Schirle, Markus
Stevanovic, Stefan
Singh-Jasuja, Harpreet
Darji, Ayub
Chakraborty, Trinad
Schild, Hansjörg
Pecht, Israel
Weiss, Siegfried
Immunodominance in CD8+ T cell responses against Listeria monocytogenes is a well-recognized but still not fully understood phenomenon. From listeriolysin, the major virulence factor of L. monocytogenes, only a single epitope, pLLO91-99, is presented by MHC class I molecules in BALB/c mice which dominates the cytotoxic T cell response against this bacterial pathogen. To obtain more insights into the molecular and cellular mechanisms underlying immunodominance of this particular epitope, we compared the various steps involved in the presentation and recognition of pLLO91-99 derived from a wild-type toxin with an equivalent epitope from a mutated toxin. This fully functional variant contains within the pLLO91-99 epitope a conservative isoleucine to alanine replacement at the C-terminal anchor residue which results in loss of antigenicity. The binding properties of the variant peptide to soluble Kd remained unaffected and cytotoxic T cells capable of recognizing the pLLO99A/Kd complex were detectable in BALB/c mice. However, such T cells required higher concentrations of antigen in order to be optimally activated in vitro. A comparison between the TAP translocation efficiency of wild-type and mutant peptide demonstrated that the mutation at the C-terminus leads to a reduced transportation rate. Furthermore, the amino acid substitution changes the in vitro proteasomal cleavage pattern, resulting in a reduced liberation of the correct peptide from a polypeptide precursor. Thus, in all assays employed the immunodominant epitope performs optimally while the variant was found to be inferior. The synergy of all these steps most likely is the decisive factor in the immunodominance of pLLO91-99.
2007-11-13T12:24:19Z
2007-11-13T12:24:19Z
2006-01-01
Article
Int. Immunol. 2006, 18(1):89-100
0953-8178
16291651
10.1093/intimm/dxh352
http://hdl.handle.net/10033/14546
en
oai:repository.helmholtz-hzi.de:10033/145182019-08-30T11:34:48Zcom_10033_6800com_10033_6799col_10033_6875
Adult murine hematopoiesis can proceed without beta1 and beta7 integrins.
Bungartz, Gerd
Stiller, Sebastian
Bauer, Martina
Müller, Werner
Schippers, Angela
Wagner, Norbert
Fässler, Reinhard
Brakebusch, Cord
The function of alpha4beta1 and alpha4beta7 integrins in hematopoiesis is controversial. While some experimental evidence suggests a crucial role for these integrins in retention and expansion of progenitor cells and lymphopoiesis, others report a less important role in hematopoiesis. Using mice with a deletion of the beta1 and the beta7 integrin genes restricted to the hematopoietic system we show here that alpha4beta1 and alpha4beta7 integrins are not essential for differentiation of lymphocytes or myelocytes. However, beta1beta7 mutant mice displayed a transient increase of colony-forming unit (CFU-C) progenitors in the bone marrow and, after phenylhydrazine-induced anemia, a decreased number of splenic erythroid colony-forming units in culture (CFUe's). Array gene expression analysis of CD4(+)CD8(+) double-positive (DP) and CD4(-)CD8(-) double-negative (DN) thymocytes and CD19(+) and CD4(+) splenocytes did not provide any evidence for a compensatory mechanism explaining the mild phenotype. These data show that alpha4beta1 and alpha4beta7 are not required for blood cell differentiation, although in their absence alterations in numbers and distribution of progenitor cells were observed.
2007-11-13T09:30:25Z
2007-11-13T09:30:25Z
2006-09-15
Article
Blood 2006, 108(6):1857-64
0006-4971
16735603
10.1182/blood-2005-10-007658
http://hdl.handle.net/10033/14518
en
oai:repository.helmholtz-hzi.de:10033/145802019-08-30T11:35:14Zcom_10033_6811com_10033_6799col_10033_6877
Immune response modifiers--mode of action.
Schiller, Meinhard
Metze, Dieter
Luger, Thomas A
Grabbe, Stephan
Gunzer, Matthias
The innate immune system governs the interconnecting pathways of microbial recognition, inflammation, microbial clearance, and cell death. A family of evolutionarily conserved receptors, known as the Toll-like receptors (TLRs), is crucial in early host defense against invading pathogens. Upon TLR stimulation, nuclear factor-kappaB activation and the interferon (IFN)-regulatory factor 3 pathway initiate production of pro-inflammatory cytokines, such as interleukin-1 and tumor necrosis factor-alpha, and production of type I IFNs (IFN-alpha and IFN-beta), respectively. The innate immunity thereby offers diverse targets for highly selective therapeutics, such as small molecular synthetic compounds that modify innate immune responses. The notion that activation of the innate immune system is a prerequisite for the induction of acquired immunity raised interest in these immune response modifiers as potential therapeutics for viral infections and various tumors. A scenario of dermal events following skin cancer treatment with imiquimod presumably comprises (i) an initial low amount of pro-inflammatory cytokine secretion by macrophages and dermal dendritic cells (DCs), thereby (ii) attracting an increasing number type I IFN-producing plasmacytoid DCs (pDCs) from the blood; (iii) Langerhans cells migrate into draining lymph nodes, leading to an increased presentation of tumor antigen in the draining lymph node, and (iv) consequently an increased generation of tumor-specific T cells and finally (v) an accumulation of tumoricidal effector cells in the treated skin area. The induction of predominately T helper (Th)1-type cytokine profiles by TLR agonists such as imiquimod might have further benefits by shifting the dominant Th2-type response in atopic diseases such as asthma and atopic dermatitis to a more potent Th1 response.
2007-11-15T12:33:05Z
2007-11-15T12:33:05Z
2006-05-01
Article
Exp. Dermatol. 2006, 15(5):331-41
0906-6705
16630072
10.1111/j.0906-6705.2006.00414.x
http://hdl.handle.net/10033/14580
en
oai:repository.helmholtz-hzi.de:10033/145932019-08-30T11:35:13Zcom_10033_6802com_10033_6799col_10033_6873
Anaerobic survival of Pseudomonas aeruginosa by pyruvate fermentation requires an Usp-type stress protein.
Schreiber, Kerstin
Boes, Nelli
Eschbach, Martin
Jaensch, Lothar
Wehland, Juergen
Bjarnsholt, Thomas
Givskov, Michael
Hentzer, Morten
Schobert, Max
Recently, we identified a pyruvate fermentation pathway in Pseudomonas aeruginosa sustaining anaerobic survival in the absence of alternative anaerobic respiratory and fermentative energy generation systems (M. Eschbach, K. Schreiber, K. Trunk, J. Buer, D. Jahn, and M. Schobert, J. Bacteriol. 186:4596-4604, 2004). Anaerobic long-term survival of P. aeruginosa might be essential for survival in deeper layers of a biofilm and the persistent infection of anaerobic mucus plaques in the cystic fibrosis lung. Proteome analysis of P. aeruginosa cells during a 7-day period of pyruvate fermentation revealed the induced synthesis of three enzymes involved in arginine fermentation, ArcA, ArcB, and ArcC, and the outer membrane protein OprL. Moreover, formation of two proteins of unknown function, PA3309 and PA4352, increased by factors of 72- and 22-fold, respectively. Both belong to the group of universal stress proteins (Usp). Long-term survival of a PA3309 knockout mutant by pyruvate fermentation was found drastically reduced. The oxygen-sensing regulator Anr controls expression of the PPA3309-lacZ reporter gene fusion after a shift to anaerobic conditions and further pyruvate fermentation. PA3309 expression was also found induced during the anaerobic and aerobic stationary phases. This aerobic stationary-phase induction is independent of the regulatory proteins Anr, RpoS, RelA, GacA, RhlR, and LasR, indicating a currently unknown mechanism of stationary-phase-dependent gene activation. PA3309 promoter activity was detected in the deeper layers of a P. aeruginosa biofilm using a PPA3309-gfp (green fluorescent protein gene) fusion and confocal laser-scanning microscopy. This is the first description of an Anr-dependent, anaerobically induced, and functional Usp-like protein in bacteria.
2007-11-16T09:32:01Z
2007-11-16T09:32:01Z
2006-01-01
Article
J. Bacteriol. 2006, 188(2):659-68
0021-9193
16385055
10.1128/JB.188.2.659-668.2006
http://hdl.handle.net/10033/14593
en
oai:repository.helmholtz-hzi.de:10033/146022019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
The making of filopodia.
Faix, Jan
Rottner, Klemens
Filopodia are rod-like cell surface projections filled with bundles of parallel actin filaments. They are found on a variety of cell types and have been ascribed sensory or exploratory functions. Filopodium formation is frequently associated with protrusion of sheet-like actin filament arrays called lamellipodia and membrane ruffles, but, in comparison to these structures, the molecular details underpinning the initiation and maintenance of filopodia are only just beginning to emerge. Recent advances have improved our understanding of the molecular requirements for filopodium protrusion and have yielded insights into the inter-relationships between lamellipodia and filopodia, the two 'sub-compartments' of the protrusive actin cytoskeleton.
2007-11-16T15:25:43Z
2007-11-16T15:25:43Z
2006-02-01
Article
Curr. Opin. Cell Biol. 2006, 18(1):18-25
0955-0674
16337369
10.1016/j.ceb.2005.11.002
http://hdl.handle.net/10033/14602
en
oai:repository.helmholtz-hzi.de:10033/146272019-08-30T11:35:13Zcom_10033_6800com_10033_6799col_10033_6875
Interleukin-10 derived from macrophages and/or neutrophils regulates the inflammatory response to LPS but not the response to CpG DNA.
Siewe, Lisa
Bollati-Fogolin, Mariela
Wickenhauser, Claudia
Krieg, Thomas
Müller, Werner
Roers, Axel
Interleukin-10 (IL-10) is an important regulator of immune responses secreted by different cell types. We have previously shown that mice with selective inactivation of the IL-10 gene in T cells suffer from deregulated T cell responses similar to those observed in IL-10(-/-) animals. Unlike IL-10(-/-) mice, however, T cell-specific mutants do not mount an enhanced innate immune response to LPS, which must, therefore, be subject to control by IL-10 from non-T cells. Herein we show that subcutaneous injection of LPS, which causes moderate local inflammation in WT and T cell-specific IL-10 mutant mice, results in augmented inflammatory infiltration and extensive tissue necrosis in mice with deficiency for IL-10 in macrophages and neutrophils. Correspondingly, we observed an enhanced sensitivity of the macrophage/neutrophil-specific IL-10 mutants to systemic LPS exposure when compared with WT animals. In contrast, the inflammatory response of these mutants to CpG oligodeoxynucleotides was not different from that of WT mice. While IL-10(-/-) mice developed massive inflammation, necrosis and increased serum cytokine levels after subcutaneous CpG injection, only moderate responses were observed in macrophage/neutrophil-specific IL-10 mutant and WT mice. These results show that different innate immune responses can be subject to control by IL-10 from different cellular sources.
2007-11-19T13:25:55Z
2007-11-19T13:25:55Z
2006-12-01
Article
Eur. J. Immunol. 2006, 36(12):3248-55
0014-2980
17111348
10.1002/eji.200636012
http://hdl.handle.net/10033/14627
en
oai:repository.helmholtz-hzi.de:10033/150122019-08-30T11:35:13Zcom_10033_6802com_10033_6799col_10033_6873
Hierarchical involvement of various GGDEF domain proteins in rdar morphotype development of Salmonella enterica serovar Typhimurium.
Kader, Abdul
Simm, Roger
Gerstel, Ulrich
Morr, Michael
Römling, Ute
Microbiology and Tumor Biology Center (MTC), Karolinska Institutet, Box 280, SE-171 77 Stockholm, Sweden.
GGDEF and EAL domain proteins are involved in the turnover of the novel secondary messenger cyclic-di(3'-->5')-guanylic acid (c-di-GMP) in many bacteria. In this work the role of the 12 GGDEF domain proteins encoded by the Salmonella enterica serovar Typhimurium (S. Typhimurium) chromosome in rdar morphotype development was investigated. Previously, it was shown that the GGDEF domain protein AdrA activated the biosynthesis of cellulose by production of c-di-GMP. Enhancement of the c-di-GMP levels by overexpression of the GGDEF domain protein AdrA did lead to the activation of curli fimbriae biosynthesis through the elevated expression of CsgD and CsgA. Although knock-out of the chromosomal copy of adrA influenced CsgA expression, CsgD expression was not altered, although more than half of the total cellular c-di-GMP was produced by AdrA at 16 h of growth. On the other hand, chromosomally encoded GGDEF-EAL domain proteins STM2123 and STM3388 were required to additively activate CsgD expression on a transcriptional and post-transcriptional level. Enhanced c-di-GMP levels did overcome temperature regulation of rdar morphotype expression by activation of curli fimbriae as well as cellulose biosynthesis through CsgD expression. Thus in the regulatory cascade leading to rdar morphotype expression c-di-GMP activates several subsequent steps in the network.
2007-12-06T09:06:00Z
2007-12-06T09:06:00Z
2006-05
Article
Hierarchical involvement of various GGDEF domain proteins in rdar morphotype development of Salmonella enterica serovar Typhimurium. 2006, 60 (3):602-16 Mol. Microbiol.
0950-382X
16629664
10.1111/j.1365-2958.2006.05123.x
http://hdl.handle.net/10033/15012
Molecular microbiology
en
oai:repository.helmholtz-hzi.de:10033/150132019-08-30T11:35:13Zcom_10033_6802com_10033_6799col_10033_6873
ISPa20 advances the individual evolution of Pseudomonas aeruginosa clone C subclone C13 strains isolated from cystic fibrosis patients by insertional mutagenesis and genomic rearrangements.
Kresse, Andreas U
Blöcker, Helmut
Römling, Ute
Research Group Clonal Variability, Division of Cell- and Immune Biology, GBF - German Research Centre for Biotechnology, Mascheroder Weg 1, 38124, Braunschweig, Germany.
Pseudomonas aeruginosa clone C strains, which chronically colonize the lungs of cystic fibrosis patients reorganize their genome structure. In this study, a novel member of the IS3 subfamily of IS elements, ISPa20, was detected which was specific for clone C subclone C13 strains. ISPa20, which was present in high copy number, mediated events of genomic reorganization. ISPa20 was inserted into P. aeruginosa backbone genes leading to adaptation to the cystic fibrosis lung habitat and into DNA acquired through horizontal gene transfer. Further on, large chromosomal inversions were mediated by ISPa20. In contrast to strains of other subclonal linages high rates of genomic rearrangements of subclone C13 strains were observed in vitro. The acquisition of mobile elements by P. aeruginosa clone C strains in the lungs of cystic fibrosis patients supports the chronic colonization by insertional mutagenesis and chromosome restructuring leading to microevolution within clone C that reflects macroevolution observed on the species level.
2007-12-06T10:15:26Z
2007-12-06T10:15:26Z
2006-05
Article
ISPa20 advances the individual evolution of Pseudomonas aeruginosa clone C subclone C13 strains isolated from cystic fibrosis patients by insertional mutagenesis and genomic rearrangements. 2006, 185 (4):245-54 Arch. Microbiol.
0302-8933
16474952
10.1007/s00203-006-0089-5
http://hdl.handle.net/10033/15013
Archives of microbiology
en
oai:repository.helmholtz-hzi.de:10033/150922019-08-30T11:32:15Zcom_10033_6805com_10033_6799col_10033_6880
Live imaging of gliobastoma cells in brain tissue shows requirement of avtin bundles for migration
CASPANI, Elisabetta M.
Echevarria, Diego
Rottner, Klemens
Small, J. Victor
2007-12-10T10:25:34Z
2007-12-10T10:25:34Z
2006
2006
Article
Neuron Glia Biology, 2 (2), pp. 105-114.
1740925X
17410533
10.1017/S1740925X06000111
http://hdl.handle.net/10033/15092
Neuron Glia Biology
Cambridge University Press
oai:repository.helmholtz-hzi.de:10033/153382019-08-30T11:31:49Zcom_10033_6804com_10033_6799col_10033_6883
Testing the importance of p27 degradation by the SCFskp2 pathway in murine models of lung and colon cancer.
Timmerbeul, Inke
Garrett-Engele, Carrie M
Kossatz, Uta
Chen, Xueyan
Firpo, Eduardo
Grünwald, Viktor
Kamino, Kenji
Wilkens, Ludwig
Lehmann, Ulrich
Buer, Jan
Geffers, Robert
Kubicka, Stefan
Manns, Michael P
Porter, Peggy L
Roberts, James M
Malek, Nisar P
Department of Gastroenterology, Hepatology, and Endocrinology, Institute for Molecular Biology, Department of Hematology and Oncology, Institute for Pathology, Hannover Medical School, D-30625 Hannover, Germany.
Decreased expression of the CDK inhibitor p27kip1 in human tumors directly correlates with increased resistance to chemotherapies, increased rates of metastasis, and an overall increased rate of patient mortality. It is thought that decreased p27 expression in tumors is caused by increased proteasomal turnover, in particular activation of the pathway governed by the SCFskp2 E3 ubiquitin protein ligase. We have directly tested the importance of the SCFskp-mediated degradation of p27 in tumorigenesis by analyzing the tumor susceptibility of mice that express a form of p27 that cannot be ubiquitinated and degraded by this pathway (p27T187A). In mouse models of both lung and colon cancer down-regulation of p27 promotes tumorigenesis. However, we found that preventing p27 degradation by the SCFskp2 pathway had no impact on tumor incidence or overall survival in either tumor model. Our study unveiled a previously unrecognized role for the control of p27 mRNA abundance in the development of non-small cell lung cancers. In the colon cancer model, the frequency of intestinal adenomas was similarly unaffected by the p27T187A mutation, but, unexpectedly, we found that it inhibited progression of intestinal adenomas to carcinomas. These studies may guide the choice of clinical settings in which pharmacologic inhibitors of the Skp2 pathway might be of therapeutic value.
2007-12-17T15:22:03Z
2007-12-17T15:22:03Z
2006-09-19
Article
Testing the importance of p27 degradation by the SCFskp2 pathway in murine models of lung and colon cancer. 2006, 103 (38):14009-14 Proc. Natl. Acad. Sci. U.S.A.
0027-8424
16966613
10.1073/pnas.0606316103
http://hdl.handle.net/10033/15338
Proceedings of the National Academy of Sciences of the United States of America
en
oai:repository.helmholtz-hzi.de:10033/159172019-08-30T11:35:39Zcom_10033_6804com_10033_6799col_10033_6883
Differential effect of auxotrophies on the release of macromolecules by Salmonella enterica vaccine strains.
Loessner, Holger
Endmann, Anne
Rohde, Manfred
Curtiss, Roy
Weiss, Siegfried
Molecular Immunology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany. holger.loessner@helmholtz-hzi.de
Attenuated Salmonella enterica strains have been widely used as live carriers for vaccines and therapeutic molecules. Appropriate attenuation has been introduced into such bacteria for safety reasons and the improvement of strain properties. Here, we compared two strains that were rendered auxotroph for diaminopimelic acid or thymidine monophosphate precursors by deletion of the genes asd or thyA, respectively. Upon removal of the complementing compound from bacterial cultures, both strains quickly lose their property to form colonies. However, while the Deltaasd bacteria lysed almost immediately under such conditions, DeltathyA bacteria remained physically intact during the observation period. As a consequence, the Deltaasd bacteria released their intracellular content such as proteins or plasmids into the supernatant. In contrast, no intracellular component, either proteins or plasmids, could be recovered from the supernatants of DeltathyA bacteria upon depletion of thymidine. Thus, the release of macromolecules from the bacterial carrier occurs as a consequence of appropriate lethal attenuation. This might substitute for sophisticated secretion systems.
2008-01-10T11:23:31Z
2008-01-10T11:23:31Z
2006-12
Article
Differential effect of auxotrophies on the release of macromolecules by Salmonella enterica vaccine strains. 2006, 265 (1):81-8 FEMS Microbiol. Lett.
0378-1097
17034415
10.1111/j.1574-6968.2006.00470.x
http://hdl.handle.net/10033/15917
FEMS microbiology letters
en
oai:repository.helmholtz-hzi.de:10033/161522019-08-30T11:31:45Zcom_10033_6812com_10033_6799col_10033_6879
Synthetic mimetics of the CD4 binding site of HIV-1 gp120 for the design of immunogens.
Franke, Raimo
Hirsch, Tatjana
Overwin, Heike
Eichler, Jutta
Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
2008-01-16T08:26:51Z
2008-01-16T08:26:51Z
2007
Article
Synthetic mimetics of the CD4 binding site of HIV-1 gp120 for the design of immunogens. 2007, 46 (8):1253-5 Angew. Chem. Int. Ed. Engl.
1433-7851
17211914
10.1002/anie.200603274
http://hdl.handle.net/10033/16152
Angewandte Chemie (International ed. in English)
en
oai:repository.helmholtz-hzi.de:10033/162332019-08-30T11:36:05Zcom_10033_6811com_10033_6799col_10033_6877
The power of single and multibeam two-photon microscopy for high-resolution and high-speed deep tissue and intravital imaging.
Niesner, Raluca
Andresen, Volker
Neumann, Jens
Spiecker, Heinrich
Gunzer, Matthias
Helmholtz Centre for Infection Research, Junior Research Group Immunodynamics, D-38124 Braunschweig, Germany.
Two-photon microscopy is indispensable for deep tissue and intravital imaging. However, current technology based on single-beam point scanning has reached sensitivity and speed limits because higher performance requires higher laser power leading to sample degradation. We utilize a multifocal scanhead splitting a laser beam into a line of 64 foci, allowing sample illumination in real time at full laser power. This technology requires charge-coupled device field detection in contrast to conventional detection by photomultipliers. A comparison of the optical performance of both setups shows functional equivalence in every measurable parameter down to penetration depths of 200 microm, where most actual experiments are executed. The advantage of photomultiplier detection materializes at imaging depths >300 microm because of their better signal/noise ratio, whereas only charge-coupled devices allow real-time detection of rapid processes (here blood flow). We also find that the point-spread function of both devices strongly depends on tissue constitution and penetration depth. However, employment of a depth-corrected point-spread function allows three-dimensional deconvolution of deep-tissue data up to an image quality resembling surface detection.
2008-01-17T09:55:02Z
2008-01-17T09:55:02Z
2007-10-01
Article
The power of single and multibeam two-photon microscopy for high-resolution and high-speed deep tissue and intravital imaging. 2007, 93 (7):2519-29 Biophys. J.
0006-3495
17557785
10.1529/biophysj.106.102459
http://hdl.handle.net/10033/16233
Biophysical journal
en
oai:repository.helmholtz-hzi.de:10033/162762019-08-30T11:36:05Zcom_10033_6804com_10033_6799col_10033_6883
Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli.
Coldewey, Sina M
Hartmann, Maike
Schmidt, Dorothea S
Engelking, Uta
Ukena, Sya N
Gunzer, Florian
Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany. sina.coldewey@web.de <sina.coldewey@web.de>
BACKGROUND: Enterohemorrhagic E. coli (EHEC), a subgroup of Shiga toxin (Stx) producing E. coli (STEC), may cause severe enteritis and hemolytic uremic syndrome (HUS) and is transmitted orally via contaminated foods or from person to person. The infectious dose is known to be very low, which requires most of the bacteria to survive the gastric acid barrier. Acid resistance therefore is an important mechanism of EHEC virulence. It should also be a relevant characteristic of E. coli strains used for therapeutic purposes such as the probiotic E. coli Nissle 1917 (EcN). In E. coli and related enteric bacteria it has been extensively demonstrated, that the alternative sigma factor sigmaS, encoded by the rpoS gene, acts as a master regulator mediating resistance to various environmental stress factors. METHODS: Using rpoS deletion mutants of a highly virulent EHEC O26:H11 patient isolate and the sequenced prototype EHEC EDL933 (ATCC 700927) of serotype O157:H7 we investigated the impact of a functional rpoS gene for orchestrating a satisfactory response to acid stress in these strains. We then functionally characterized rpoS of probiotic EcN and five rpoS genes selected from STEC isolates pre-investigated for acid resistance. RESULTS: First, we found out that ATCC isolate 700927 of EHEC EDL933 has a point mutation in rpoS, not present in the published sequence, leading to a premature stop codon. Moreover, to our surprise, one STEC strain as well as EcN was acid sensitive in our test environment, although their cloned rpoS genes could effectively complement acid sensitivity of an rpoS deletion mutant. CONCLUSION: The attenuation of sequenced EHEC EDL933 might be of importance for anyone planning to do either in vitro or in vivo studies with this prototype strain. Furthermore our data supports recently published observations, that individual E. coli isolates are able to significantly modulate their acid resistance phenotype independent of their rpoS genotype.
2008-01-17T14:24:19Z
2008-01-17T14:24:19Z
2007
Article
Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli. 2007, 7:21 BMC Microbiol.
1471-2180
17386106
10.1186/1471-2180-7-21
http://hdl.handle.net/10033/16276
BMC microbiology
en
oai:repository.helmholtz-hzi.de:10033/181552019-08-30T11:36:04Zcom_10033_6807com_10033_6799col_10033_6884
c-Met is essential for wound healing in the skin.
Chmielowiec, Jolanta
Borowiak, Malgorzata
Morkel, Markus
Stradal, Theresia
Munz, Barbara
Werner, Sabine
Wehland, Jürgen
Birchmeier, Carmen
Birchmeier, Walter
Department of Cancer Biology, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany.
Wound healing of the skin is a crucial regenerative process in adult mammals. We examined wound healing in conditional mutant mice, in which the c-Met gene that encodes the receptor of hepatocyte growth factor/scatter factor was mutated in the epidermis by cre recombinase. c-Met-deficient keratinocytes were unable to contribute to the reepithelialization of skin wounds. In conditional c-Met mutant mice, wound closure was slightly attenuated, but occurred exclusively by a few (5%) keratinocytes that had escaped recombination. This demonstrates that the wound process selected and amplified residual cells that express a functional c-Met receptor. We also cultured primary keratinocytes from the skin of conditional c-Met mutant mice and examined them in scratch wound assays. Again, closure of scratch wounds occurred by the few remaining c-Met-positive cells. Our data show that c-Met signaling not only controls cell growth and migration during embryogenesis but is also essential for the generation of the hyperproliferative epithelium in skin wounds, and thus for a fundamental regenerative process in the adult.
2008-02-13T14:22:33Z
2008-02-13T14:22:33Z
2007-04-09
Article
c-Met is essential for wound healing in the skin. 2007, 177 (1):151-62 J. Cell Biol.
0021-9525
17403932
10.1083/jcb.200701086
http://hdl.handle.net/10033/18155
The Journal of cell biology
en
oai:repository.helmholtz-hzi.de:10033/191782019-08-30T11:36:32Zcom_10033_6804com_10033_6799col_10033_6883
Salmonella enterica serovar typhimurium exploits inflammation to compete with the intestinal microbiota.
Stecher, Bärbel
Robbiani, Riccardo
Walker, Alan W
Westendorf, Astrid M
Barthel, Manja
Kremer, Marcus
Chaffron, Samuel
Macpherson, Andrew J
Buer, Jan
Parkhill, Julian
Dougan, Gordon
von Mering, Christian
Hardt, Wolf-Dietrich
Institute of Microbiology, Swiss Institute of Technology Zurich, Zurich, Switzerland.
Most mucosal surfaces of the mammalian body are colonized by microbial communities ("microbiota"). A high density of commensal microbiota inhabits the intestine and shields from infection ("colonization resistance"). The virulence strategies allowing enteropathogenic bacteria to successfully compete with the microbiota and overcome colonization resistance are poorly understood. Here, we investigated manipulation of the intestinal microbiota by the enteropathogenic bacterium Salmonella enterica subspecies 1 serovar Typhimurium (S. Tm) in a mouse colitis model: we found that inflammatory host responses induced by S. Tm changed microbiota composition and suppressed its growth. In contrast to wild-type S. Tm, an avirulent invGsseD mutant failing to trigger colitis was outcompeted by the microbiota. This competitive defect was reverted if inflammation was provided concomitantly by mixed infection with wild-type S. Tm or in mice (IL10(-/-), VILLIN-HA(CL4-CD8)) with inflammatory bowel disease. Thus, inflammation is necessary and sufficient for overcoming colonization resistance. This reveals a new concept in infectious disease: in contrast to current thinking, inflammation is not always detrimental for the pathogen. Triggering the host's immune defence can shift the balance between the protective microbiota and the pathogen in favour of the pathogen.
2008-02-26T14:00:54Z
2008-02-26T14:00:54Z
2007-10
Article
Salmonella enterica serovar typhimurium exploits inflammation to compete with the intestinal microbiota. 2007, 5 (10):2177-89 PLoS Biol.
1545-7885
17760501
10.1371/journal.pbio.0050244
http://hdl.handle.net/10033/19178
PLoS biology
en
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17760501
oai:repository.helmholtz-hzi.de:10033/191962019-08-30T11:36:59Zcom_10033_6811com_10033_6799col_10033_6877
Environmental dimensionality controls the interaction of phagocytes with the pathogenic fungi Aspergillus fumigatus and Candida albicans.
Behnsen, Judith
Narang, Priyanka
Hasenberg, Mike
Gunzer, Frank
Bilitewski, Ursula
Klippel, Nina
Rohde, Manfred
Brock, Matthias
Brakhage, Axel A
Gunzer, Matthias
Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Jena, Germany.
The fungal pathogens Aspergillus fumigatus and Candida albicans are major health threats for immune-compromised patients. Normally, macrophages and neutrophil granulocytes phagocytose inhaled Aspergillus conidia in the two-dimensional (2-D) environment of the alveolar lumen or Candida growing in tissue microabscesses, which are composed of a three-dimensional (3-D) extracellular matrix. However, neither the cellular dynamics, the per-cell efficiency, the outcome of this interaction, nor the environmental impact on this process are known. Live imaging shows that the interaction of phagocytes with Aspergillus or Candida in 2-D liquid cultures or 3-D collagen environments is a dynamic process that includes phagocytosis, dragging, or the mere touching of fungal elements. Neutrophils and alveolar macrophages efficiently phagocytosed or dragged Aspergillus conidia in 2-D, while in 3-D their function was severely impaired. The reverse was found for phagocytosis of Candida. The phagocytosis rate was very low in 2-D, while in 3-D most neutrophils internalized multiple yeasts. In competitive assays, neutrophils primarily incorporated Aspergillus conidia in 2-D and Candida yeasts in 3-D despite frequent touching of the other pathogen. Thus, phagocytes show activity best in the environment where a pathogen is naturally encountered. This could explain why "delocalized" Aspergillus infections such as hematogeneous spread are almost uncontrollable diseases, even in immunocompetent individuals.
2008-02-26T14:15:58Z
2008-02-26T14:15:58Z
2007-02
Article
Environmental dimensionality controls the interaction of phagocytes with the pathogenic fungi Aspergillus fumigatus and Candida albicans. 2007, 3 (2):e13 PLoS Pathog.
1553-7374
17274685
10.1371/journal.ppat.0030013
http://hdl.handle.net/10033/19196
PLoS pathogens
en
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17274685
oai:repository.helmholtz-hzi.de:10033/195572019-08-30T11:32:37Zcom_10033_6812com_10033_6799col_10033_6879
Structural and functional mimicry of the binding site of hYAP-WW domain for proline-rich ligands
Strijowski, Ulf
Hirsch, Tatjana
Quintilla, Aina
Wenzel, Wolfgang
Eichler, Jutta
Helmholtz Centre for Infection Research
2008-03-03T15:16:45Z
2008-03-03T15:16:45Z
2007-06
Article
International Journal of Peptide Research and Therapeutics; 13 (1-2); pp. 245-250.
15733149
1573496X
10.1007/s10989-006-9074-8
http://hdl.handle.net/10033/19557
International Journal of Peptide Research and Therapeutics
Springer
oai:repository.helmholtz-hzi.de:10033/197572019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
Cdc42 and phosphoinositide 3-kinase drive Rac-mediated actin polymerization downstream of c-Met in distinct and common pathways.
Bosse, Tanja
Ehinger, Julia
Czuchra, Aleksandra
Benesch, Stefanie
Steffen, Anika
Wu, Xunwei
Schloen, Kathrin
Niemann, Hartmut H
Scita, Giorgio
Stradal, Theresia E B
Brakebusch, Cord
Rottner, Klemens
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research (HZI), Inhoffenstrasse 7, D-38124, Braunschweig, Germany.
Activation of c-Met, the hepatocyte growth factor (HGF)/scatter factor receptor induces reorganization of the actin cytoskeleton, which drives epithelial cell scattering and motility and is exploited by pathogenic Listeria monocytogenes to invade nonepithelial cells. However, the precise contributions of distinct Rho-GTPases, the phosphatidylinositol 3-kinases, and actin assembly regulators to c-Met-mediated actin reorganization are still elusive. Here we report that HGF-induced membrane ruffling and Listeria invasion mediated by the bacterial c-Met ligand internalin B (InlB) were significantly impaired but not abrogated upon genetic removal of either Cdc42 or pharmacological inhibition of phosphoinositide 3-kinase (PI3-kinase). While loss of Cdc42 or PI3-kinase function correlated with reduced HGF- and InlB-triggered Rac activation, complete abolishment of actin reorganization and Rac activation required the simultaneous inactivation of both Cdc42 and PI3-kinase signaling. Moreover, Cdc42 activation was fully independent of PI3-kinase activity, whereas the latter partly depended on Cdc42. Finally, Cdc42 function did not require its interaction with the actin nucleation-promoting factor N-WASP. Instead, actin polymerization was driven by Arp2/3 complex activation through the WAVE complex downstream of Rac. Together, our data establish an intricate signaling network comprising as key molecules Cdc42 and PI3-kinase, which converge on Rac-mediated actin reorganization essential for Listeria invasion and membrane ruffling downstream of c-Met.
2008-03-05T09:59:13Z
2008-03-05T09:59:13Z
2007-10
Article
Cdc42 and phosphoinositide 3-kinase drive Rac-mediated actin polymerization downstream of c-Met in distinct and common pathways. 2007, 27 (19):6615-28 Mol. Cell. Biol.
0270-7306
17682062
10.1128/MCB.00367-07
http://hdl.handle.net/10033/19757
Molecular and cellular biology
en
oai:repository.helmholtz-hzi.de:10033/221732019-08-30T11:34:48Zcom_10033_6800com_10033_6799col_10033_6875
Serum response factor contributes selectively to lymphocyte development.
Fleige, Anne
Alberti, Siegfried
Gröbe, Lothar
Frischmann, Ursula
Geffers, Robert
Müller, Werner
Nordheim, Alfred
Schippers, Angela
Department of Experimental Immunology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.
Serum response factor (SRF), is a crucial transcription factor for murine embryonic development and for the function of muscle cells and neurons. Gene expression data show that SRF and its transcriptional cofactors are also expressed in lymphocyte precursors and mature lymphocytes. However, the role of SRF in lymphocyte development has not been addressed in vivo so far, attributed in part to early embryonic lethality of conventional Srf-null mice. To determine the in vivo role of SRF in developing lymphocytes, we specifically inactivated the murine Srf gene during T or B cell development using lymphocyte-specific Cre transgenic mouse lines. T cell-specific Srf deletion led to a severe block in thymocyte development at the transition from CD4/CD8 double to single positive stage. The few residual T cells detectable in the periphery retained at least one functional Srf allele, thereby demonstrating the importance of SRF in T cell development. In contrast, deletion of Srf in developing B cells did not interfere with the growth and survival of B cells in general, yet led to a complete loss of marginal zone B cells and a marked reduction of the CD5+ B cell subset. Our study also revealed a contribution of SRF to the expression of the surface molecules IgM, CD19, and the chemokine receptor 4 in B lymphocytes. We conclude that SRF fulfills essential and distinct functions in the differentiation of different types of lymphocytes.
2008-04-03T08:37:01Z
2008-04-03T08:37:01Z
2007-08-17
Article
Serum response factor contributes selectively to lymphocyte development. 2007, 282 (33):24320-8 J. Biol. Chem.
0021-9258
17591768
10.1074/jbc.M703119200
http://hdl.handle.net/10033/22173
The Journal of biological chemistry
en
oai:repository.helmholtz-hzi.de:10033/223532019-08-30T11:37:23Zcom_10033_6800com_10033_6799col_10033_6875
MUGEN mouse database; animal models of human immunological diseases.
Aidinis, V
Chandras, C
Manoloukos, M
Thanassopoulou, A
Kranidioti, K
Armaka, M
Douni, E
Kontoyiannis, D L
Zouberakis, M
Kollias, G
B.S.R.C. Alexander Fleming, 34 Fleming Street, 16672, Vari, Greece. v.aidinis@fleming.gr
The MUGEN mouse database (MMdb) (www.mugen-noe.org/database/) is a database of murine models of immune processes and immunological diseases. Its aim is to share and publicize information on mouse strain characteristics and availability from participating institutions. MMdb's basic classification of models is based on three major research application categories: Models of Human Disease, Models of Immune Processes and Transgenic Tools. Data on mutant strains includes detailed information on affected gene(s), mutant allele(s) and genetic background (DNA origin, gene targeted, host and backcross strain background). Each gene/transgene index also includes IDs and direct links to Ensembl, ArrayExpress, EURExpress and NCBI's Entrez Gene database. Phenotypic description is standardized and hierarchically structured, based on MGI's mammalian phenotypic ontology terms. Availability (e.g. live mice, cryopreserved embryos, sperm and ES cells) is clearly indicated, along with handling and genotyping details (in the form of documents or hyperlinks) and all relevant contact information (including EMMA and Jax/IMSR hyperlinks where available). MMdb's design offers a user-friendly query interface and provides instant access to the list of mutant strains and genes. Database access is free of charge and there are no registration requirements for data querying.
2008-04-04T14:39:02Z
2008-04-04T14:39:02Z
2008-01
Article
MUGEN mouse database; animal models of human immunological diseases. 2008, 36 (Database issue):D1048-54 Nucleic Acids Res.
1362-4962
17932065
10.1093/nar/gkm838
http://hdl.handle.net/10033/22353
Nucleic acids research
en
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=17932065
oai:repository.helmholtz-hzi.de:10033/224122019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
Arp2/3 complex interactions and actin network turnover in lamellipodia.
Lai, FP
Szczodrak, M
Block, J
Faix, J
Breitsprecher, D
Mannherz, HG
Stradal, TE
Dunn, GA
Small, JV
Rottner, K
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Cell migration is initiated by lamellipodia-membrane-enclosed sheets of cytoplasm containing densely packed actin filament networks. Although the molecular details of network turnover remain obscure, recent work points towards key roles in filament nucleation for Arp2/3 complex and its activator WAVE complex. Here, we combine fluorescence recovery after photobleaching (FRAP) of different lamellipodial components with a new method of data analysis to shed light on the dynamics of actin assembly/disassembly. We show that Arp2/3 complex is incorporated into the network exclusively at the lamellipodium tip, like actin, at sites coincident with WAVE complex accumulation. Capping protein likewise showed a turnover similar to actin and Arp2/3 complex, but was confined to the tip. In contrast, cortactin-another prominent Arp2/3 complex regulator-and ADF/cofilin-previously implicated in driving both filament nucleation and disassembly-were rapidly exchanged throughout the lamellipodium. These results suggest that Arp2/3- and WAVE complex-driven actin filament nucleation at the lamellipodium tip is uncoupled from the activities of both cortactin and cofilin. Network turnover is additionally regulated by the spatially segregated activities of capping protein at the tip and cofilin throughout the mesh.
2008-04-07T09:08:14Z
2008-04-07T09:08:14Z
2008-02-28
Article
Arp2/3 complex interactions and actin network turnover in lamellipodia. 2008: EMBO J.
1460-2075
18309290
10.1038/emboj.2008.34
http://hdl.handle.net/10033/22412
The EMBO journal
null
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18309290
oai:repository.helmholtz-hzi.de:10033/234322019-08-30T11:37:23Zcom_10033_6800com_10033_6799col_10033_6875
LMP1 signaling can replace CD40 signaling in B cells in vivo and has unique features of inducing class-switch recombination to IgG1.
Rastelli, Julia
Hömig-Hölzel, Cornelia
Seagal, Jane
Müller, Werner
Hermann, Andrea C
Rajewsky, Klaus
Zimber-Strobl, Ursula
Institute of Clinical Molecular Biology and Tumor Genetics, GSF-National Research Center for Environment and Health, Munich, Germany.
The Epstein-Barr virus (EBV) protein LMP1 is considered to be a functional homologue of the CD40 receptor. However, in contrast to the latter, LMP1 is a constitutively active signaling molecule. To compare B cell-specific LMP1 and CD40 signaling in an unambiguous manner, we generated transgenic mice conditionally expressing a CD40/LMP1 fusion protein, which retained the LMP1 cytoplasmic tail but has lost the constitutive activity of LMP1 and needs to be activated by the CD40 ligand. We show that LMP1 signaling can completely substitute CD40 signaling in B cells, leading to normal B-cell development, activation, and immune responses including class-switch recombination, germinal center formation, and somatic hypermutation. In addition, the LMP1-signaling domain has a unique property in that it can induce class-switch recombination to IgG1 independent of cytokines. Thus, our data indicate that LMP1 has evolved to imitate T-helper cell function allowing activation, proliferation, and differentiation of EBV-infected B cells independent of T cells.
2008-04-15T12:32:49Z
2008-04-15T12:32:49Z
2008-02-01
Article
LMP1 signaling can replace CD40 signaling in B cells in vivo and has unique features of inducing class-switch recombination to IgG1. 2008, 111 (3):1448-55 Blood
0006-4971
18006702
10.1182/blood-2007-10-117655
http://hdl.handle.net/10033/23432
Blood
en
oai:repository.helmholtz-hzi.de:10033/251532019-08-30T11:26:42Zcom_10033_6804com_10033_6799col_10033_6883
Lack of interferon-beta leads to accelerated remyelination in a toxic model of central nervous system demyelination.
Trebst, Corinna
Heine, Sandra
Lienenklaus, Stefan
Lindner, Maren
Baumgärtner, Wolfgang
Weiss, Siegfried
Stangel, Martin
Department of Neurology, Medical School Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Interferon-beta (IFN-beta) is a pleiotropic cytokine that is known to modulate the immune response in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). Spontaneous remyelination and repair mechanisms in MS are mostly insufficient and contribute to clinical disability. Here, we investigated whether IFN-beta has a potential in modifying the extent of de- and remyelination in a toxic model of CNS demyelination induced by the copper chelator cuprizone. IFN-beta deficient (k/o) mice showed an accelerated spontaneous remyelination. However, the amount of remyelination after 6 weeks did not differ between the two groups. Demyelination in IFN-beta k/o mice was paralleled by a diminished astrocytic and microglia response as compared with wildtype controls, whereas the accelerated remyelination was paralleled by an increased number of oligodendrocyte precursor cells (OPC) within the demyelinated lesion at the beginning of the remyelination phase. We hypothesize that the absence of IFN-beta leads to more efficient recruitment and proliferation of OPC already during demyelination, thus allowing early remyelination. These results demonstrate that IFN-beta is able to alter remyelination in the absence of an immune-mediated demyelination.
2008-05-08T14:10:16Z
2008-05-08T14:10:16Z
2007-12
Article
Lack of interferon-beta leads to accelerated remyelination in a toxic model of central nervous system demyelination. 2007, 114 (6):587-96 Acta Neuropathol.
0001-6322
17940777
10.1007/s00401-007-0300-z
http://hdl.handle.net/10033/25153
Acta neuropathologica
en
oai:repository.helmholtz-hzi.de:10033/281522019-08-30T11:26:42Zcom_10033_6804com_10033_6799col_10033_6883
Sensitivity to Escherichia coli Nissle 1917 in mice is dependent on environment and genetic background.
Bleich, Andre
Sundberg, John P
Smoczek, Anna
von Wasielewski, Reinhard
de Buhr, Maike F
Janus, Lydia M
Julga, Gwen
Ukena, Sya N
Hedrich, Hans-J
Gunzer, Florian
Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany. bleich.andre@mh-hannover.de
Escherichia coli Nissle 1917 (EcN) is a well-characterized probiotic bacterium. Although genomic comparisons of EcN with the uropathogenic E. coli strain CFT073 revealed high degrees of similarity, EcN is generally considered a non-pathogenic organism. However, as recent evidence suggests that EcN is capable of inducing inflammatory responses in host intestinal epithelial cells, we aimed to investigate potential pathogenic properties of EcN in an in vivo model using various germ-free (GF) mouse strains. With the exception of C3H/HeJZtm mice, which carry a defective toll-like receptor (TLR)4-allele, no lesions were obvious in mice of different strains orally inoculated with EcN for 1 week, although organ cultures (blood, lung, mesenteric lymph node, pancreas, spleen, liver and kidney) tested positive to various degrees. C3H/HeJZtm mice inoculated with EcN became clinically ill and the majority died or had to be euthanized. Organs of all gnotobiotic C3H/HeJZtm mice were positive for EcN by culture; major histological findings were moderate to severe pyogranulomatous serositis, typhlitis and pancreatitis. Histological findings were corroborated by highly elevated tumour necrosis factor (TNF) serum levels. Lesions were not detected in specified pathogen free maintained C3H/HeJZtm mice, GF C3H/HeJ mice lacking the interleukin-10 gene, or GF C3H/HeJZtm mice that were inoculated with E. coli K12 strain MG1655 as a control. In addition, mild histological lesions were detected in Ztm:NMRI mice 3 months after oral inoculation with EcN. This study shows that EcN is capable of displaying a virulent phenotype in GF C3H/HeJZtm mice. Whether this phenotype is linked to the bacterium's probiotic nature should be the focus of further studies.
2008-05-26T13:15:34Z
2008-05-26T13:15:34Z
2008-02
Article
Sensitivity to Escherichia coli Nissle 1917 in mice is dependent on environment and genetic background. 2008, 89 (1):45-54notInt J Exp Pathol
1365-2613
18005134
10.1111/j.1365-2613.2007.00560.x
http://hdl.handle.net/10033/28152
International journal of experimental pathology
en
oai:repository.helmholtz-hzi.de:10033/303942019-08-30T11:27:46Zcom_10033_6802com_10033_6799col_10033_6873
The aryl hydrocarbon receptor links TH17-cell-mediated autoimmunity to environmental toxins.
Veldhoen, Marc
Hirota, Keiji
Westendorf, Astrid M
Buer, Jan
Dumoutier, Laure
Renauld, Jean-Christophe
Stockinger, Brigitta
Division of Molecular Immunology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK.
The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor best known for mediating the toxicity of dioxin. Environmental factors are believed to contribute to the increased prevalence of autoimmune diseases, many of which are due to the activity of T(H)17 T cells, a new helper T-cell subset characterized by the production of the cytokine IL-17. Here we show that in the CD4+ T-cell lineage of mice AHR expression is restricted to the T(H)17 cell subset and its ligation results in the production of the T(H)17 cytokine interleukin (IL)-22. AHR is also expressed in human T(H)17 cells. Activation of AHR by a high-affinity ligand during T(H)17 cell development markedly increases the proportion of T(H)17 T cells and their production of cytokines. CD4+ T cells from AHR-deficient mice can develop T(H)17 cell responses, but when confronted with AHR ligand fail to produce IL-22 and do not show enhanced T(H)17 cell development. AHR activation during induction of experimental autoimmune encephalomyelitis causes accelerated onset and increased pathology in wild-type mice, but not AHR-deficient mice. AHR ligands may therefore represent co-factors in the development of autoimmune diseases.
2008-06-24T12:14:28Z
2008-06-24T12:14:28Z
2008-05-01
Article
The aryl hydrocarbon receptor links TH17-cell-mediated autoimmunity to environmental toxins. 2008, 453 (7191):106-9 Nature
1476-4687
18362914
10.1038/nature06881
http://hdl.handle.net/10033/30394
Nature
en
oai:repository.helmholtz-hzi.de:10033/303952019-08-30T11:33:05Zcom_10033_6802com_10033_6799col_10033_6873
Pathogenomics: an updated European Research Agenda.
Demuth, Andreas
Aharonowitz, Yair
Bachmann, Till T
Blum-Oehler, Gabriele
Buchrieser, Carmen
Covacci, Antonello
Dobrindt, Ulrich
Emödy, Levente
van der Ende, Arie
Ewbank, Jonathan
Fernández, Luis Angel
Frosch, Matthias
Portillo, Francisco García-Del
Gilmore, Michael S
Glaser, Philippe
Goebel, Werner
Hasnain, Seyed E
Heesemann, Jürgen
Islam, Khalid
Korhonen, Timo
Maiden, Martin
Meyer, Thomas F
Montecucco, Cesare
Oswald, Eric
Parkhill, Julian
Pucciarelli, M Graciela
Ron, Eliora
Svanborg, Catharina
Uhlin, Bernt Eric
Wai, Sun Nyunt
Wehland, Jürgen
Hacker, Jörg
Institut für Molekulare Infektionsbiologie, Röntgenring 11, 97070 Würzburg, Germany.
The emerging genomic technologies and bioinformatics provide novel opportunities for studying life-threatening human pathogens and to develop new applications for the improvement of human and animal health and the prevention, treatment, and diagnosis of infections. Based on the ecology and population biology of pathogens and related organisms and their connection to epidemiology, more accurate typing technologies and approaches will lead to better means of disease control. The analysis of the genome plasticity and gene pools of pathogenic bacteria including antigenic diversity and antigenic variation results in more effective vaccines and vaccine implementation programs. The study of newly identified and uncultivated microorganisms enables the identification of new threats. The scrutiny of the metabolism of the pathogen in the host allows the identification of new targets for anti-infectives and therapeutic approaches. The development of modulators of host responses and mediators of host damage will be facilitated by the research on interactions of microbes and hosts, including mechanisms of host damage, acute and chronic relationships as well as commensalisms. The study of multiple pathogenic and non-pathogenic microbes interacting in the host will improve the management of multiple infections and will allow probiotic and prebiotic interventions. Needless to iterate, the application of the results of improved prevention and treatment of infections into clinical tests will have a positive impact on the management of human and animal disease. The Pathogenomics Research Agenda draws on discussions with experts of the Network of Excellence "EuroPathoGenomics" at the management board meeting of the project held during 18-21 April 2007, in the Villa Vigoni, Menaggio, Italy. Based on a proposed European Research Agenda in the field of pathogenomics by the ERA-NET PathoGenoMics the meeting's participants updated the established list of topics as the research agenda for the future.
2008-06-24T13:28:21Z
2008-06-24T13:28:21Z
2008-05
Article
Pathogenomics: an updated European Research Agenda. 2008, 8 (3):386-93 Infect. Genet. Evol.
1567-1348
18321793
10.1016/j.meegid.2008.01.005
http://hdl.handle.net/10033/30395
Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases
en
oai:repository.helmholtz-hzi.de:10033/359722019-08-30T11:25:11Zcom_10033_6802com_10033_6799col_10033_6873
Fitness of isogenic colony morphology variants of Pseudomonas aeruginosa in murine airway infection.
Rakhimova, Elza
Munder, Antje
Wiehlmann, Lutz
Bredenbruch, Florian
Tümmler, Burkhard
Clinical Research Group, OE6710, Hanover Medical School, Hanover, Germany.
Chronic lung infections with Pseudomonas aeruginosa are associated with the diversification of the persisting clone into niche specialists and morphotypes, a phenomenon called 'dissociative behaviour'. To explore the potential of P. aeruginosa to change its morphotype by single step loss-of-function mutagenesis, a signature-tagged mini-Tn5 plasposon library of the cystic fibrosis airway isolate TBCF10839 was screened for colony morphology variants under nine different conditions in vitro. Transposon insertion into 1% of the genome changed colony morphology into eight discernable morphotypes. Half of the 55 targets encode features of primary or secondary metabolism whereby quinolone production was frequently affected. In the other half the transposon had inserted into genes of the functional categories transport, regulation or motility/chemotaxis. To mimic dissociative behaviour of isogenic strains in lungs, pools of 25 colony morphology variants were tested for competitive fitness in an acute murine airway infection model. Six of the 55 mutants either grew better or worse in vivo than in vitro, respectively. Metabolic proficiency of the colony morphology variant was a key determinant for survival in murine airways. The most common morphotype of self-destructive autolysis did unexpectedly not impair fitness. Transposon insertions into homologous genes of strain PAO1 did not reproduce the TBCF10839 mutant morphotypes for 16 of 19 examined loci pointing to an important role of the genetic background on colony morphology. Depending on the chosen P. aeruginosa strain, functional genome scans will explore other areas of the evolutionary landscape. Based on our discordant findings of mutant phenotypes in P. aeruginosa strains PAO1, PA14 and TBCF10839, we conclude that the current focus on few reference strains may miss modes of niche adaptation and dissociative behaviour that are relevant for the microevolution of complex traits in the wild.
2008-08-20T12:52:47Z
2008-08-20T12:52:47Z
2008
Article
Fitness of isogenic colony morphology variants of Pseudomonas aeruginosa in murine airway infection. 2008, 3 (2):e1685 PLoS ONE
1932-6203
18301762
10.1371/journal.pone.0001685
http://hdl.handle.net/10033/35972
PLoS ONE
en
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0001685
oai:repository.helmholtz-hzi.de:10033/360522019-08-30T11:31:49Zcom_10033_6804com_10033_6799col_10033_6883
Hypermetabolic syndrome as a consequence of repeated psychological stress in mice.
Depke, Maren
Fusch, Gerhard
Domanska, Grazyna
Geffers, Robert
Völker, Uwe
Schuett, Christine
Kiank, Cornelia
Ernst-Moritz-Arndt-University, Interfaculty Institute of Genetics and Functional Genomics, 17487 Greifswald, Germany.
Stress is a powerful modulator of neuroendocrine, behavioral, and immunological functions. After 4.5-d repeated combined acoustic and restraint stress as a murine model of chronic psychological stress, severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with the severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turnover, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure, changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice. Thus, in our murine model, repeated stress caused severe metabolic dysregulations, leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.
2008-08-21T09:28:28Z
2008-08-21T09:28:28Z
2008-06
Article
Hypermetabolic syndrome as a consequence of repeated psychological stress in mice. 2008, 149 (6):2714-23 Endocrinology
0013-7227
18325986
10.1210/en.2008-0038
http://hdl.handle.net/10033/36052
Endocrinology
en
oai:repository.helmholtz-hzi.de:10033/362122019-08-30T11:31:49Zcom_10033_6800com_10033_6799col_10033_6875
Constitutive CD40 signaling in B cells selectively activates the noncanonical NF-kappaB pathway and promotes lymphomagenesis.
Hömig-Hölzel, Cornelia
Hojer, Caroline
Rastelli, Julia
Casola, Stefano
Strobl, Lothar J
Müller, Werner
Quintanilla-Martinez, Leticia
Gewies, Andreas
Ruland, Jürgen
Rajewsky, Klaus
Zimber-Strobl, Ursula
Institute of Clinical Molecular Biology and Tumor Genetics, Helmholtz Center Munich, German Research Center for Environment and Health, D-81377 Munich, Germany.
CD40, a member of the tumor necrosis factor (TNF) receptor family, plays an essential role in T cell-dependent immune responses. Because CD40 is widely expressed on the surface of tumor cells in various B cell malignancies, deregulated CD40 signaling has been suggested to contribute to lymphomagenesis. In this study, we show that B cell-specific expression of a constitutively active CD40 receptor, in the form of a latent membrane protein 1 (LMP1)/CD40 chimeric protein, promoted an increase in the number of follicular and marginal zone B cells in secondary lymphoid organs in transgenic mice. The B cells displayed an activated phenotype, prolonged survival and increased proliferation, but were significantly impaired in T cell-dependent immune responses. Constitutive CD40 signaling in B cells induced selective and constitutive activation of the noncanonical NF-kappaB pathway and the mitogen-activated protein kinases Jnk and extracellular signal-regulated kinase. LMP1/CD40-expressing mice older than 12 mo developed B cell lymphomas of mono- or oligoclonal origin at high incidence, thus showing that the interplay of the signaling pathways induced by constitutive CD40 signaling is sufficient to initiate a tumorigenic process, ultimately leading to the development of B cell lymphomas.
2008-08-22T08:58:57Z
2008-08-22T08:58:57Z
2008-06-09
Article
Constitutive CD40 signaling in B cells selectively activates the noncanonical NF-kappaB pathway and promotes lymphomagenesis. 2008, 205 (6):1317-29 J. Exp. Med.
1540-9538
18490492
10.1084/jem.20080238
http://hdl.handle.net/10033/36212
The Journal of experimental medicine
en
oai:repository.helmholtz-hzi.de:10033/368122019-08-30T11:33:05Zcom_10033_6805com_10033_6799col_10033_6880
On the Rho'd: the regulation of membrane protrusions by Rho-GTPases.
Ladwein, Markus
Rottner, Klemens
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research (HZI), Inhoffen Strasse 7, D-38124 Braunschweig, Germany.
Cell migration entails the formation of cellular protrusions such as lamellipodia or filopodia, the growth of which is powered by the polymerisation of actin filaments abutting the plasma membrane. Specific Rho-GTPase subfamilies are able to drive different types of protrusions. However, significant crosstalk between Rho-family members and the interplay of distinct Rho-effectors regulating or modulating actin reorganization in protrusions complicate the picture of how precisely they are initiated and maintained. Here, we briefly sketch our current knowledge on structure and dynamics of different protrusions as well as their regulation by Rho-GTPases. We also comment on topical, unresolved controversies in the field, with special emphasis on the interrelation of different protrusion types, and on the composition of the nanomachineries driving them.
2008-08-29T08:49:47Z
2008-08-29T08:49:47Z
2008-06-18
Article
On the Rho'd: the regulation of membrane protrusions by Rho-GTPases. 2008, 582 (14):2066-74 FEBS Lett.
0014-5793
18442478
10.1016/j.febslet.2008.04.033
http://hdl.handle.net/10033/36812
FEBS letters
en
oai:repository.helmholtz-hzi.de:10033/382032019-08-30T11:27:39Zcom_10033_6811com_10033_6799col_10033_6877
Fluorescence lifetime imaging in biosciences: Technologies and applications
Niesner, Raluca
Gericke, Karl-Heinz
2008-09-26T11:47:35Z
2008-09-26T11:47:35Z
2008-02-01
Article
Frontiers of Physics in China, 3(2008)88-104
http://hdl.handle.net/10033/38203
oai:repository.helmholtz-hzi.de:10033/478092019-08-30T11:31:23Zcom_10033_6807com_10033_6799col_10033_6884
Free Brick1 is a trimeric precursor in the assembly of a functional wave complex.
Derivery, Emmanuel
Fink, Jenny
Martin, Davy
Houdusse, Anne
Piel, Matthieu
Stradal, Theresia E
Louvard, Daniel
Gautreau, Alexis
Institut Curie, Centre de Recherche, Morphogenesis and Cell Signaling laboratory, Paris, France.
BACKGROUND: The Wave complex activates the Arp2/3 complex, inducing actin polymerization in lamellipodia and membrane ruffles. The Wave complex is composed of five subunits, the smallest of which, Brick1/Hspc300 (Brk1), is the least characterized. We previously reported that, unlike the other subunits, Brk1 also exists as a free form. PRINCIPAL FINDINGS: Here we report that this free form of Brk1 is composed of homotrimers. Using a novel assay in which purified free Brk1 is electroporated into HeLa cells, we were able to follow its biochemical fate in cells and to show that free Brk1 becomes incorporated into the Wave complex. Importantly, incorporation of free Brk1 into the Wave complex was blocked upon inhibition of protein synthesis and incorporated Brk1 was found to associate preferentially with neosynthesized subunits. Brk1 depleted HeLa cells were found to bleb, as were Nap1, Wave2 or ARPC2 depleted cells, suggesting that this blebbing phenotype of Brk1 depleted cells is due to an impairment of the Wave complex function rather than a specific function of free Brk1. Blebs of Brk1 depleted cells were emitted at sites where lamellipodia and membrane ruffles were normally emitted. In Brk1 depleted cells, the electroporation of free Brk1 was sufficient to restore Wave complex assembly and to rescue the blebbing phenotype. CONCLUSION: Together these results establish that the free form of Brk1 is an essential precursor in the assembly of a functional Wave complex.
2009-01-21T15:28:19Z
2009-01-21T15:28:19Z
2008
Article
Free Brick1 is a trimeric precursor in the assembly of a functional wave complex. 2008, 3 (6):e2462 PLoS ONE
1932-6203
18560548
10.1371/journal.pone.0002462
http://hdl.handle.net/10033/47809
PLoS ONE
en
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002462
oai:repository.helmholtz-hzi.de:10033/478102019-08-30T11:28:24Zcom_10033_6802com_10033_6799col_10033_6873
Marine biofilm bacteria evade eukaryotic predation by targeted chemical defense.
Matz, Carsten
Webb, Jeremy S
Schupp, Peter J
Phang, Shui Yen
Penesyan, Anahit
Egan, Suhelen
Steinberg, Peter
Kjelleberg, Staffan
School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney, Australia.
Many plants and animals are defended from predation or herbivory by inhibitory secondary metabolites, which in the marine environment are very common among sessile organisms. Among bacteria, where there is the greatest metabolic potential, little is known about chemical defenses against bacterivorous consumers. An emerging hypothesis is that sessile bacterial communities organized as biofilms serve as bacterial refuge from predation. By testing growth and survival of two common bacterivorous nanoflagellates, we find evidence that chemically mediated resistance against protozoan predators is common among biofilm populations in a diverse set of marine bacteria. Using bioassay-guided chemical and genetic analysis, we identified one of the most effective antiprotozoal compounds as violacein, an alkaloid that we demonstrate is produced predominately within biofilm cells. Nanomolar concentrations of violacein inhibit protozoan feeding by inducing a conserved eukaryotic cell death program. Such biofilm-specific chemical defenses could contribute to the successful persistence of biofilm bacteria in various environments and provide the ecological and evolutionary context for a number of eukaryote-targeting bacterial metabolites.
2009-01-21T15:32:37Z
2009-01-21T15:32:37Z
2008
Article
Marine biofilm bacteria evade eukaryotic predation by targeted chemical defense. 2008, 3 (7):e2744 PLoS ONE
1932-6203
18648491
10.1371/journal.pone.0002744
http://hdl.handle.net/10033/47810
PLoS ONE
en
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002744
oai:repository.helmholtz-hzi.de:10033/482442019-08-30T11:30:58Zcom_10033_6805com_10033_6799col_10033_6880
Differentially oriented populations of actin filaments generated in lamellipodia collaborate in pushing and pausing at the cell front.
Koestler, Stefan A
Auinger, Sonja
Vinzenz, Marlene
Rottner, Klemens
Small, J Victor
Institute of Molecular Biotechnology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
Eukaryotic cells advance in phases of protrusion, pause and withdrawal. Protrusion occurs in lamellipodia, which are composed of diagonal networks of actin filaments, and withdrawal terminates with the formation of actin bundles parallel to the cell edge. Using correlated live-cell imaging and electron microscopy, we have shown that actin filaments in protruding lamellipodia subtend angles from 15-90 degrees to the front, and that transitions from protrusion to pause are associated with a proportional increase in filaments oriented more parallel to the cell edge. Microspike bundles of actin filaments also showed a wide angular distribution and correspondingly variable bilateral polymerization rates along the cell front. We propose that the angular shift of filaments in lamellipodia serves in adapting to slower protrusion rates while maintaining the filament densities required for structural support; further, we suggest that single filaments and microspike bundles contribute to the construction of the lamella behind and to the formation of the cell edge when protrusion ceases. Our findings provide an explanation for the variable turnover dynamics of actin filaments in lamellipodia observed by fluorescence speckle microscopy and are inconsistent with a current model of lamellipodia structure that features actin filaments branching at 70 degrees in a dendritic array.
2009-01-30T14:11:51Z
2009-01-30T14:11:51Z
2008-03
Article
Differentially oriented populations of actin filaments generated in lamellipodia collaborate in pushing and pausing at the cell front. 2008, 10 (3):306-13 Nat. Cell Biol.
1476-4679
18278037
10.1038/ncb1692
http://hdl.handle.net/10033/48244
Nature cell biology
en
oai:repository.helmholtz-hzi.de:10033/483942019-08-30T11:32:16Zcom_10033_6800com_10033_6799col_10033_6875
Mouse Phenotype Database Integration Consortium: integration [corrected] of mouse phenome data resources.
Hancock, John M
Adams, Niels C
Aidinis, Vassilis
Blake, Andrew
Bogue, Molly
Brown, Steve D M
Chesler, Elissa J
Davidson, Duncan
Duran, Christopher
Eppig, Janan T
Gailus-Durner, Valérie
Gates, Hilary
Gkoutos, Georgios V
Greenaway, Simon
Hrabé de Angelis, Martin
Kollias, George
Leblanc, Sophie
Lee, Kirsty
Lengger, Christoph
Maier, Holger
Mallon, Ann-Marie
Masuya, Hiroshi
Melvin, David G
Müller, Werner
Parkinson, Helen
Proctor, Glenn
Reuveni, Eli
Schofield, Paul
Shukla, Aadya
Smith, Cynthia
Toyoda, Tetsuro
Vasseur, Laurent
Wakana, Shigeharu
Walling, Alison
White, Jacqui
Wood, Joe
Zouberakis, Michalis
Understanding the functions encoded in the mouse genome will be central to an understanding of the genetic basis of human disease. To achieve this it will be essential to be able to characterize the phenotypic consequences of variation and alterations in individual genes. Data on the phenotypes of mouse strains are currently held in a number of different forms (detailed descriptions of mouse lines, first-line phenotyping data on novel mutations, data on the normal features of inbred lines) at many sites worldwide. For the most efficient use of these data sets, we have initiated a process to develop standards for the description of phenotypes (using ontologies) and file formats for the description of phenotyping protocols and phenotype data sets. This process is ongoing and needs to be supported by the wider mouse genetics and phenotyping communities to succeed. We invite interested parties to contact us as we develop this process further.
2009-02-03T15:13:12Z
2009-02-03T15:13:12Z
2007-03
Article
Mouse Phenotype Database Integration Consortium: integration [corrected] of mouse phenome data resources. 2007, 18 (3):157-63 Mamm. Genome
0938-8990
17436037
10.1007/s00335-007-9004-x
http://hdl.handle.net/10033/48394
Mammalian genome : official journal of the International Mammalian Genome Society
en
oai:repository.helmholtz-hzi.de:10033/485432019-08-30T11:27:16Zcom_10033_6805com_10033_6799col_10033_6880
Filopodia formation induced by active mDia2/Drf3.
Block, J
Stradal, T E B
Hänisch, J
Geffers, Robert
Köstler, S A
Urban, E
Small, J V
Rottner, K
Faix, J
Cytoskeleton Dynamics Group, Helmholtz Centre for Infection Research, Braunschweig, Germany.
Filopodia are rod-shaped cell surface protrusions composed of a parallel bundle of actin filaments. Since filopodia frequently emanate from lamellipodia, it has been proposed that they form exclusively by the convergence and elongation of actin filaments generated in lamellipodia networks. However, filopodia form without Arp2/3-complex, which is essential for lamellipodia formation, indicating that actin filaments in filopodia may be generated by other nucleators. Here we analyzed the effects of ectopic expression of GFP-tagged full length or a constitutively active variant of the human formin mDia2/Drf3. By contrast to the full-length molecule, which did not affect cell behaviour and was entirely cytosolic, active Drf3 lacking the C-terminal regulatory region (Drf3DeltaDAD) induced the formation of filopodia and accumulated at their tips. Low expression of Drf3DeltaDAD induced rod-shaped or tapered filopodia, whereas over-expression resulted in multiple, club-shaped filopodia. The clubs were filled with densely bundled actin filaments, whose number but not packing density decreased further away from the tip. Interestingly, clubs frequently increased in width after protrusion beyond the cell periphery, which correlated with increased amounts of Drf3DeltaDAD at their tips. These data suggest Drf3-induced filopodia form and extend by de novo nucleation of actin filaments instead of convergent elongation. Finally, Drf3DeltaDAD also induced the formation of unusual, lamellipodia-like structures, which contained both lamellipodial markers and the prominent filopodial protein fascin. Microarray analyses revealed highly variable Drf3 expression levels in different commonly used cell lines, reflecting the need for more detailed analyses of the functions of distinct formins in actin cytoskeleton turnover and different cell types.
2009-02-05T15:40:21Z
2009-02-05T15:40:21Z
2008-09
Article
Filopodia formation induced by active mDia2/Drf3. 2008, 231 (3):506-17notJ Microsc
1365-2818
18755006
10.1111/j.1365-2818.2008.02063.x
http://hdl.handle.net/10033/48543
Journal of microscopy
en
oai:repository.helmholtz-hzi.de:10033/642532019-08-30T11:34:22Zcom_10033_6802com_10033_6799col_10033_6873
Quantitative determination of cyclic diguanosine monophosphate concentrations in nucleotide extracts of bacteria by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.
Simm, Roger
Morr, Michael
Remminghorst, Uwe
Andersson, Mats
Römling, Ute
Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.
The physiological response to small molecules (secondary messengers) is the outcome of a delicate equilibrium between biosynthesis and degradation of the signal. Cyclic diguanosine monophosphate (c-di-GMP) is a novel secondary messenger present in many bacteria. It has a complex cellular metabolism whereby usually more than one enzyme synthesizing and degrading c-di-GMP is encoded by a bacterial genome. To assess the in vivo conditions of c-di-GMP signaling, we developed a high-performance liquid chromatography (HPLC)-mass spectrometry-based method to detect c-di-GMP with high sensitivity and to quantify the c-di-GMP concentration in the bacterial cell as described here in detail. We successfully used the methodology to determine and compare the c-di-GMP concentrations in bacterial species such as Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Vibrio cholerae. We describe the use of the methodology to assess the change in c-di-GMP concentration during the growth phase and the contribution of a point mutation in S. typhimurium to the overall cellular c-di-GMP concentration.
2009-04-03T12:53:23Z
2009-04-03T12:53:23Z
2009-03-01
Article
Quantitative determination of cyclic diguanosine monophosphate concentrations in nucleotide extracts of bacteria by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. 2009, 386 (1):53-8 Anal. Biochem.
1096-0309
19135022
10.1016/j.ab.2008.12.013
http://hdl.handle.net/10033/64253
Analytical biochemistry
en
oai:repository.helmholtz-hzi.de:10033/705752019-08-30T11:33:29Zcom_10033_6805com_10033_6799col_10033_6880
F- and G-actin concentrations in lamellipodia of moving cells.
Koestler, Stefan A
Rottner, Klemens
Lai, Frank
Block, Jennifer
Vinzenz, Marlene
Small, J Victor
Institute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna, Austria.
Cells protrude by polymerizing monomeric (G) into polymeric (F) actin at the tip of the lamellipodium. Actin filaments are depolymerized towards the rear of the lamellipodium in a treadmilling process, thereby supplementing a G-actin pool for a new round of polymerization. In this scenario the concentrations of F- and G-actin are principal parameters, but have hitherto not been directly determined. By comparing fluorescence intensities of bleached and unbleached regions of lamellipodia in B16-F1 mouse melanoma cells expressing EGFP-actin, before and after extraction with Triton X-100, we show that the ratio of F- to G-actin is 3.2+/-0.9. Using electron microscopy to determine the F-actin content, this ratio translates into F- and G-actin concentrations in lamellipodia of approximately 500 microM and 150 microM, respectively. The excess of G-actin, at several orders of magnitude above the critical concentrations at filament ends indicates that the polymerization rate is not limited by diffusion and is tightly controlled by polymerization/depolymerization modulators.
2009-06-16T13:02:06Z
2009-06-16T13:02:06Z
2009
Article
F- and G-actin concentrations in lamellipodia of moving cells. 2009, 4 (3):e4810 PLoS ONE
1932-6203
19277198
10.1371/journal.pone.0004810
http://hdl.handle.net/10033/70575
PloS one
en
oai:repository.helmholtz-hzi.de:10033/711182019-08-30T11:34:22Zcom_10033_6800com_10033_6799col_10033_6875
Maternal farm exposure modulates neonatal immune mechanisms through regulatory T cells.
Schaub, Bianca
Liu, Jing
Höppler, Sabine
Schleich, Isolde
Huehn, Jochen
Olek, Sven
Wieczorek, Georg
Illi, Sabina
von Mutius, Erika
Department of Pulmonary and Allergy, University Children's Hospital Munich, LMU Munich, Munich, Germany. Bianca.Schaub@med.uni-muenchen.de
BACKGROUND: Cross-sectional studies suggest that maternal exposure to farming decreases the risk of allergic diseases in offspring. The potential underlying immunologic mechanisms are not understood. OBJECTIVE: We sought to assess whether maternal farm exposure activates regulatory T (Treg) cells in cord blood, exerting T(H)2-suppressive effects after microbial stimulation. METHODS: Eighty-four pregnant mothers were recruited before delivery. Detailed questionnaires (60 nonfarming and 22 farming mothers with 2 exclusions) assessed the farming exposures. Cord blood was stimulated with the microbial stimulus peptidoglycan (Ppg), the mitogen PHA, house dust mite extracts (Der p 1), and combinations. Treg cells (CD4+CD25(high) cells; intracellular forkhead/winged-helix family transcriptional repressor p3 [FOXP3] expression, FOXP3 levels, lymphocyte activation gene 3 mRNA expression, functional studies, and DNA methylation of the FOXP3 locus), proliferation, and T(H)2/T(H)1/T(H)17 cytokines were examined. RESULTS: Cord blood Treg cell counts (both unstimulated and PHA stimulated) were increased with maternal farming exposures and associated with higher FOXP3 (Der p 1 + Ppg stimulation) and trendwise higher lymphocyte activation gene 3 (Ppg) expression. Furthermore, Treg cell function was more efficient with farming exposure (effector cell suppression, P = .004). In parallel, T(H)2 cytokine (IL-5) levels were decreased and associated with decreased lymphoproliferation and increased IL-6 levels (Ppg stimulation, Der p 1 + Ppg stimulation, or both; P < .05). Maternal exposure to increasing numbers of farm animals and stables was discovered to exert distinct effects on Treg cells, T(H)1/T(H)2 cells, or both. Additionally, FOXP3 demethylation in offspring of mothers with farm milk exposure was increased (P = .02). CONCLUSIONS: Farm exposures during pregnancy increase the number and function of cord blood Treg cells associated with lower T(H)2 cytokine secretion and lymphocyte proliferation on innate exposure. One fascinating speculation is that maternal farm exposure might reflect a natural model of immunotherapy, potentially including a selection of innate stimuli in addition to allergen, shaping a child's immune system at an early stage.
2009-06-22T13:20:17Z
2009-06-22T13:20:17Z
2009-04
Article
Maternal farm exposure modulates neonatal immune mechanisms through regulatory T cells. 2009, 123 (4):774-82.e5 J. Allergy Clin. Immunol.
1097-6825
19348917
10.1016/j.jaci.2009.01.056
http://hdl.handle.net/10033/71118
The Journal of allergy and clinical immunology
en
oai:repository.helmholtz-hzi.de:10033/770732019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
Filopodia: Complex models for simple rods.
Faix, Jan
Breitsprecher, Dennis
Stradal, Theresia E B
Rottner, Klemens
Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany. faix@bpc.mh-hannover.de
Filopodia are prominent cell surface projections filled with bundles of linear actin filaments that drive their protrusion. These structures are considered important sensory organelles, for instance in neuronal growth cones or during the fusion of sheets of epithelial tissues. In addition, they can serve a precursor function in adhesion site or stress fibre formation. Actin filament assembly is essential for filopodia formation and turnover, yet the precise molecular mechanisms of filament nucleation and/or elongation are controversial. Indeed, conflicting reports on the molecular requirements of filopodia initiation have prompted researchers to propose different types and/or alternative or redundant mechanisms mediating this process. However, recent data shed new light on these questions, and they indicate that the balance of a limited set of biochemical activities can determine the structural outcome of a given filopodium. Here we focus on discussing our current view of the relevance of these activities, and attempt to propose a molecular mechanism of filopodia assembly based on a single core machinery.
2009-08-12T13:07:50Z
2009-08-12T13:07:50Z
2009-08-12T13:07:50Z
Article
Filopodia: Complex models for simple rods., 41 (8-9):1656-64 Int. J. Biochem. Cell Biol.
1878-5875
19433307
10.1016/j.biocel.2009.02.012
http://hdl.handle.net/10033/77073
The international journal of biochemistry & cell biology
en
oai:repository.helmholtz-hzi.de:10033/847672019-08-30T11:34:48Zcom_10033_6805com_10033_6799col_10033_6880
Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions.
Himmel, Mirko
Ritter, Anett
Rothemund, Sven
Pauling, Björg V
Rottner, Klemens
Gingras, Alexandre R
Ziegler, Wolfgang H
Interdisciplinary Centre for Clinical Research (IZKF) Leipzig, Faculty of Medicine, University of Leipzig, D-04103 Leipzig, Germany.
In cell-extracellular matrix junctions (focal adhesions), the cytoskeletal protein talin is central to the connection of integrins to the actin cytoskeleton. Talin is thought to mediate this connection via its two integrin, (at least) three actin, and several vinculin binding sites. The binding sites are cryptic in the head-to-rod autoinhibited cytoplasmic form of the protein and require (stepwise) conformational activation. This activation process, however, remains poorly understood, and there are contradictory models with respect to the determinants of adhesion site localization. Here, we report turnover rates and protein-protein interactions in a range of talin rod domain constructs varying in helix bundle structure. We conclude that several bundles of the C terminus cooperate to regulate targeting and concomitantly tailor high affinity interactions of the talin rod in cell adhesions. Intrinsic control of ligand binding activities is essential for the coordination of adhesion site function of talin.
2009-10-23T14:02:31Z
2009-10-23T14:02:31Z
2009-05-15
Article
Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions. 2009, 284 (20):13832-42 J. Biol. Chem.
0021-9258
19278997
10.1074/jbc.M900266200
http://hdl.handle.net/10033/84767
The Journal of biological chemistry
en
oai:repository.helmholtz-hzi.de:10033/872372019-08-30T11:35:14Zcom_10033_6804com_10033_6799col_10033_6883
Type I interferon drives tumor necrosis factor-induced lethal shock.
Huys, Liesbeth
Van Hauwermeiren, Filip
Dejager, Lien
Dejonckheere, Eline
Lienenklaus, Stefan
Weiss, Siegfried
Leclercq, Georges
Libert, Claude
Department for Molecular Biomedical Research, VIB, Ghent B9052, Belgium.
Tumor necrosis factor (TNF) is reputed to have very powerful antitumor effects, but it is also a strong proinflammatory cytokine. Injection of TNF in humans and mice leads to a systemic inflammatory response syndrome with major effects on liver and bowels. TNF is also a central mediator in several inflammatory diseases. We report that type I interferons (IFNs) are essential mediators of the lethal response to TNF. Mice deficient in the IFN-alpha receptor 1 (IFNAR-1) or in IFN-beta are remarkably resistant to TNF-induced hypothermia and death. After TNF injection, IFNAR-1(-/-) mice produced less IL-6, had less bowel damage, and had less apoptosis of enterocytes and hepatocytes compared with wild-type (WT) mice. Extensive gene expression analysis in livers of WT and IFNAR-1(-/-) mice revealed a large deficiency in the response to TNF in the knockout mice, especially of IFN-stimulated response element-dependent genes, many of which encode chemokines. In livers of IFNAR-1(-/-) mice, fewer infiltrating white blood cells (WBCs) were detected by immunohistochemistry. Deficiency of type I IFN signaling provided sufficient protection for potentially safer therapeutic use of TNF in tumor-bearing mice. Our data illustrate that type I IFNs act as essential mediators in TNF-induced lethal inflammatory shock, possibly by enhancing cell death and inducing chemokines and WBC infiltration in tissues.
2009-12-02T15:31:30Z
2009-12-02T15:31:30Z
2009-08-31
Article
Type I interferon drives tumor necrosis factor-induced lethal shock. 2009, 206 (9):1873-82 J. Exp. Med.
1540-9538
19687227
10.1084/jem.20090213
http://hdl.handle.net/10033/87237
The Journal of experimental medicine
en
oai:repository.helmholtz-hzi.de:10033/941532019-08-30T11:35:13Zcom_10033_6804com_10033_6799col_10033_6883
Probiotic Escherichia coli Nissle 1917 inhibits leaky gut by enhancing mucosal integrity.
Ukena, Sya N
Singh, Anurag
Dringenberg, Ulrike
Engelhardt, Regina
Seidler, Ursula
Hansen, Wiebke
Bleich, André
Bruder, Dunja
Franzke, Anke
Rogler, Gerhard
Suerbaum, Sebastian
Buer, Jan
Gunzer, Florian
Westendorf, Astrid M
Department of Mucosal Immunity, Helmholtz Centre for Infection Research, Braunschweig, Germany.
BACKGROUND: Probiotics are proposed to positively modulate the intestinal epithelial barrier formed by intestinal epithelial cells (IECs) and intercellular junctions. Disruption of this border alters paracellular permeability and is a key mechanism for the development of enteric infections and inflammatory bowel diseases (IBDs). METHODOLOGY AND PRINCIPAL FINDINGS: To study the in vivo effect of probiotic Escherichia coli Nissle 1917 (EcN) on the stabilization of the intestinal barrier under healthy conditions, germfree mice were colonized with EcN or K12 E. coli strain MG1655. IECs were isolated and analyzed for gene and protein expression of the tight junction molecules ZO-1 and ZO-2. Then, in order to analyze beneficial effects of EcN under inflammatory conditions, the probiotic was orally administered to BALB/c mice with acute dextran sodium sulfate (DSS) induced colitis. Colonization of gnotobiotic mice with EcN resulted in an up-regulation of ZO-1 in IECs at both mRNA and protein levels. EcN administration to DSS-treated mice reduced the loss of body weight and colon shortening. In addition, infiltration of the colon with leukocytes was ameliorated in EcN inoculated mice. Acute DSS colitis did not result in an anion secretory defect, but abrogated the sodium absorptive function of the mucosa. Additionally, intestinal barrier function was severely affected as evidenced by a strong increase in the mucosal uptake of Evans blue in vivo. Concomitant administration of EcN to DSS treated animals resulted in a significant protection against intestinal barrier dysfunction and IECs isolated from these mice exhibited a more pronounced expression of ZO-1. CONCLUSION AND SIGNIFICANCE: This study convincingly demonstrates that probiotic EcN is able to mediate up-regulation of ZO-1 expression in murine IECs and confer protection from the DSS colitis-associated increase in mucosal permeability to luminal substances.
2010-03-12T09:20:52Z
2010-03-12T09:20:52Z
2007
Article
Probiotic Escherichia coli Nissle 1917 inhibits leaky gut by enhancing mucosal integrity. 2007, 2 (12):e1308 PLoS ONE
1932-6203
18074031
10.1371/journal.pone.0001308
http://hdl.handle.net/10033/94153
PloS one
en
oai:repository.helmholtz-hzi.de:10033/940932019-08-30T11:35:13Zcom_10033_6802com_10033_6799col_10033_6873
SiaA and SiaD are essential for inducing autoaggregation as a specific response to detergent stress in Pseudomonas aeruginosa.
Klebensberger, Janosch
Birkenmaier, Antoinette
Geffers, Robert
Kjelleberg, Staffan
Philipp, Bodo
Universität Konstanz, Fachbereich Biologie, Mikrobielle Okologie, Fach M654, 78457 Konstanz, Germany.
Cell aggregation is a stress response and serves as a survival strategy for Pseudomonas aeruginosa strain PAO1 during growth with the toxic detergent Na-dodecylsulfate (SDS). This process involves the psl operon and is linked to c-di-GMP signalling. The induction of cell aggregation in response to SDS was studied. Transposon and site-directed mutagenesis revealed that the cupA-operon and the co-transcribed genes siaA (PA0172) and siaD (PA0169) were essential for SDS-induced aggregation. While siaA encodes a putative membrane protein with a HAMP and a PP2C-like phosphatase domain, siaD encodes a putative diguanylate cyclase involved in the biosynthesis of c-di-GMP. Complementation studies uncovered that the loss of SDS-induced aggregation in the formerly isolated spontaneous mutant strain N was caused by a non-functional siaA allele. DNA-microarray analysis of SDS-grown cells revealed consistent activation of eight genes, including cupA1, with known or presumptive important functions in cell aggregation in the parent strain compared with non-aggregating siaA and siaD mutants. A siaAD-dependent increase of cupA1 mRNA levels in SDS-grown cells was also shown by Northern blots. These results clearly demonstrate that SiaAD are essential for inducing cell aggregation as a specific response to SDS and suggest that they are responsible for perceiving and transducing SDS-related stress.
2010-03-11T09:20:53Z
2010-03-11T09:20:53Z
2009-12
Article
SiaA and SiaD are essential for inducing autoaggregation as a specific response to detergent stress in Pseudomonas aeruginosa. 2009, 11 (12):3073-86 Environ. Microbiol.
1462-2920
19638175
10.1111/j.1462-2920.2009.02012.x
http://hdl.handle.net/10033/94093
Environmental microbiology
en
oai:repository.helmholtz-hzi.de:10033/959752019-08-30T11:29:17Zcom_10033_6804com_10033_6799col_10033_6883
The host response to the probiotic Escherichia coli strain Nissle 1917: specific up-regulation of the proinflammatory chemokine MCP-1.
Ukena, Sya N
Westendorf, Astrid M
Hansen, Wiebke
Rohde, Manfred
Geffers, Robert
Coldewey, Sina
Suerbaum, Sebastian
Buer, Jan
Gunzer, Florian
German Research Centre for Biotechnology, Mucosal Immunity Group, Mascheroder Weg 1, 38124 Braunschweig, Germany. suk@gbf.de
BACKGROUND: The use of live microorganisms to influence positively the course of intestinal disorders such as infectious diarrhea or chronic inflammatory conditions has recently gained increasing interest as a therapeutic alternative. In vitro and in vivo investigations have demonstrated that probiotic-host eukaryotic cell interactions evoke a large number of responses potentially responsible for the effects of probiotics. The aim of this study was to improve our understanding of the E. coli Nissle 1917-host interaction by analyzing the gene expression pattern initiated by this probiotic in human intestinal epithelial cells. METHODS: Gene expression profiles of Caco-2 cells treated with E. coli Nissle 1917 were analyzed with microarrays. A second human intestinal cell line and also pieces of small intestine from BALB/c mice were used to confirm regulatory data of selected genes by real-time RT-PCR and cytometric bead array (CBA) to detect secretion of corresponding proteins. RESULTS: Whole genome expression analysis revealed 126 genes specifically regulated after treatment of confluent Caco-2 cells with E. coli Nissle 1917. Among others, expression of genes encoding the proinflammatory molecules monocyte chemoattractant protein-1 ligand 2 (MCP-1), macrophage inflammatory protein-2 alpha (MIP-2alpha) and macrophage inflammatory protein-2 beta (MIP-2beta) was increased up to 10 fold. Caco-2 cells cocultured with E. coli Nissle 1917 also secreted high amounts of MCP-1 protein. Elevated levels of MCP-1 and MIP-2alpha mRNA could be confirmed with Lovo cells. MCP-1 gene expression was also up-regulated in mouse intestinal tissue. CONCLUSION: Thus, probiotic E. coli Nissle 1917 specifically upregulates expression of proinflammatory genes and proteins in human and mouse intestinal epithelial cells.
2010-04-08T09:10:02Z
2010-04-08T09:10:02Z
2005
Article
The host response to the probiotic Escherichia coli strain Nissle 1917: specific up-regulation of the proinflammatory chemokine MCP-1. 2005, 6:43 BMC Med. Genet.
1471-2350
16351713
10.1186/1471-2350-6-43
http://hdl.handle.net/10033/95975
BMC medical genetics
en
oai:repository.helmholtz-hzi.de:10033/961922019-08-30T11:35:39Zcom_10033_6802com_10033_6799col_10033_6873
Analysis of Cd14 as a genetic modifier of experimental inflammatory bowel disease (IBD) in mice.
de Buhr, Maike F
Hedrich, Hans-J
Westendorf, Astrid M
Obermeier, Florian
Hofmann, Claudia
Zschemisch, Nils-H
Buer, Jan
Bumann, Dirk
Goyert, Sanna M
Bleich, Andre
Insitute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany.
BACKGROUND AND AIM:: By combining QTL and gene expression analyses, we have previously identified Cd14 as a potential candidate gene contributing to the differential IBD susceptibility of C3H/HeJBir (C3/J)-Il10(-/-) mice [carrying IBD-resistance alleles at this QTL (Cdcs6)] and C57BL/6J (B6)-Il10(-/-) mice, corroborating studies that showed an association of a CD14-promoter polymorphism with Crohn's disease and ulcerative colitis. The aim of the present study was to analyze the molecular mechanisms leading to differential intestinal expression of Cd14 and its contribution to IBD development. METHODS:: Intestinal CD14 expression was assessed by FACS, immunohistochemistry, and ELISA on supernatants of primary epithelial cell and tissue cultures. RAW264.7 cells were stimulated with LPS and PGN in the presence or absence of CD14. Cd14 alleles were sequenced and promoters cloned for luciferase assays in transfected RAW264.7 cells. The severity of typhlocolitis between Cd14(-/-) and wild-type mice was compared in 2 distinct mouse models of IBD (acute DSS and Il10(-/-)). RESULTS:: In the gut, CD14 was detected mainly in its soluble form (sCD14), with higher expression in C3/J-Il10(-/-) mice. Polymorphisms in C3/J mice caused higher activity of the Cd14 promoter (luciferase assays). Intestinal sCD14 concentrations influenced the LPS and PGN responses of RAW264.7 cells. In vivo, genetic deletion of Cd14 aggravated colitis in both mouse models of IBD. CONCLUSIONS:: Our study shows that Cd14-promoter polymorphisms affect CD14 expression and confirms the protective effect of CD14 against experimental IBD, potentially mediated by TLR2- and TLR4-dependent effects on intestinal barrier function. These findings support the concept that human CD14-promoter polymorphisms contribute to disease development. Inflamm Bowel Dis 2009.
2010-04-09T14:26:29Z
2010-04-09T14:26:29Z
2009-07-27
Article
Analysis of Cd14 as a genetic modifier of experimental inflammatory bowel disease (IBD) in mice. 2009, 15 (12):1824-1836 Inflamm. Bowel Dis.
1536-4844
19637338
10.1002/ibd.21030
http://hdl.handle.net/10033/96192
Inflammatory bowel diseases
oai:repository.helmholtz-hzi.de:10033/965972019-08-30T11:34:48Zcom_10033_6804com_10033_6799col_10033_6883
Drug-inducible remote control of gene expression by probiotic Escherichia coli Nissle 1917 in intestine, tumor and gall bladder of mice.
Loessner, Holger
Leschner, Sara
Endmann, Anne
Westphal, Kathrin
Wolf, Kathrin
Kochruebe, Katja
Miloud, Tewfik
Altenbuchner, Josef
Weiss, Siegfried
Molecular Immunology, Helmholtz Centre for Infection Research, HZI, Inhoffenstrasse 7, 38124 Braunschweig, Germany. loeho@pei.de
The probiotic bacterium Escherichia coli Nissle 1917 (EcN) constitutes a prospective vector for delivering heterologous therapeutic molecules to treat several human disorders. To add versatility to this carrier system, bacteria should be equipped with expression modules that can be regulated deliberately in a temporal and quantitative manner. This approach is called in vivo remote control (IVRC) of bacterial vectors. Here, we have evaluated promoters P(araBAD), P(rhaBAD) and P(tet), which can be induced with L-arabinose, L-rhamnose or anhydrotetracycline, respectively. EcN harboring promoter constructs with luciferase as reporter gene were administered either orally to healthy mice or intravenously to tumor bearing animals. Subsequent to bacterial colonization of tissues, inducer substances were administered via the oral or systemic route. By use of in vivo bioluminescence imaging, the time course of reporter gene expression was analyzed. Each promoter displayed a specific in vivo induction profile depending on the niche of bacterial residence and the route of inducer administration. Importantly, we also observed colonization of gall bladders of mice when EcN was administered systemically at high doses. Bacteria in this anatomical compartment remained accessible to remote control of bacterial gene expression.
2010-04-15T12:06:20Z
2010-04-15T12:06:20Z
2009-12
Article
Drug-inducible remote control of gene expression by probiotic Escherichia coli Nissle 1917 in intestine, tumor and gall bladder of mice. 2009, 11 (14-15):1097-105 Microbes Infect.
1769-714X
19665575
10.1016/j.micinf.2009.08.002
http://hdl.handle.net/10033/96597
Microbes and infection / Institut Pasteur
en
oai:repository.helmholtz-hzi.de:10033/979792019-08-30T11:35:39Zcom_10033_6805com_10033_6799col_10033_6880
Molecular dissection of Salmonella-induced membrane ruffling versus invasion.
Hänisch, Jan
Ehinger, Julia
Ladwein, Markus
Rohde, Manfred
Derivery, Emmanuel
Bosse, Tanja
Steffen, Anika
Bumann, Dirk
Misselwitz, Benjamin
Hardt, Wolf-Dietrich
Gautreau, Alexis
Stradal, Theresia E B
Rottner, Klemens
Helmholtz Centre for Infection Research, Braunschweig, Germany.
Type III secretion system-mediated injection of a cocktail of bacterial proteins drives actin rearrangements, frequently adopting the shape of prominent protuberances of ruffling membrane, and culminating in host cell invasion of Gram-negative pathogens like Salmonella typhimurium. Different Salmonella effectors are able to bind actin and activate Rho-family GTPases, which have previously been implicated in mediating actin-dependent Salmonella entry by interacting with N-WASP or WAVE-complex, well-established activators of the actin nucleation machine Arp2/3-complex. Using genetic deletion and RNA interference studies, we show here that neither individual nor collective removal of these Arp2/3- complex activators affected host cell invasion as efficiently as Arp2/3-complex knock-down, although the latter was also not essential. However, interference with WAVE-complex function abrogated Salmonella-induced membrane ruffling without significantly affecting entry efficiency, actin or Arp2/3-complex accumulation. In addition, scanning electron microscopy images captured entry events in the absence of prominent membrane ruffles. Finally, localization and RNA interference studies indicated a relevant function in Salmonella entry for the novel Arp2/3-complex regulator WASH. These data establish for the first time that Salmonella invasion is separable from bacteria-induced membrane ruffling, and uncover an additional Arp2/3-complex activator as well as an Arp2/3-complex-independent actin assembly activity that contribute to Salmonella invasion.
2010-05-05T13:49:53Z
2010-05-05T13:49:53Z
2010-01
Article
Molecular dissection of Salmonella-induced membrane ruffling versus invasion. 2010, 12 (1):84-98 Cell. Microbiol.
1462-5822
19732055
10.1111/j.1462-5822.2009.01380.x
http://hdl.handle.net/10033/97979
Cellular microbiology
en
oai:repository.helmholtz-hzi.de:10033/1068892019-08-30T11:35:39Zcom_10033_6807com_10033_6799col_10033_6884
Rac1 regulates neuronal polarization through the WAVE complex.
Tahirovic, Sabina
Hellal, Farida
Neukirchen, Dorothee
Hindges, Robert
Garvalov, Boyan K
Flynn, Kevin C
Stradal, Theresia E
Chrostek-Grashoff, Anna
Brakebusch, Cord
Bradke, Frank
Axonal Growth and Regeneration Group, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany.
Neuronal migration and axon growth, key events during neuronal development, require distinct changes in the cytoskeleton. Although many molecular regulators of polarity have been identified and characterized, relatively little is known about their physiological role in this process. To study the physiological function of Rac1 in neuronal development, we have generated a conditional knock-out mouse, in which Rac1 is ablated in the whole brain. Rac1-deficient cerebellar granule neurons, which do not express other Rac isoforms, showed impaired neuronal migration and axon formation both in vivo and in vitro. In addition, Rac1 ablation disrupts lamellipodia formation in growth cones. The analysis of Rac1 effectors revealed the absence of the Wiskott-Aldrich syndrome protein (WASP) family verprolin-homologous protein (WAVE) complex from the plasma membrane of knock-out growth cones. Loss of WAVE function inhibited axon growth, whereas overexpression of a membrane-tethered WAVE mutant partially rescued axon growth in Rac1-knock-out neurons. In addition, pharmacological inhibition of the WAVE complex effector Arp2/3 also reduced axon growth. We propose that Rac1 recruits the WAVE complex to the plasma membrane to enable actin remodeling necessary for axon growth.
2010-06-28T08:50:24Z
2010-06-28T08:50:24Z
2010-05-19
Article
Rac1 regulates neuronal polarization through the WAVE complex. 2010, 30 (20):6930-43 J. Neurosci.
1529-2401
20484635
10.1523/JNEUROSCI.5395-09.2010
http://hdl.handle.net/10033/106889
The Journal of neuroscience : the official journal of the Society for Neuroscience
en
oai:repository.helmholtz-hzi.de:10033/1170752019-08-30T11:35:39Zcom_10033_6802com_10033_6799col_10033_6873
Local induction of immunosuppressive CD8+ T cells in the gut-associated lymphoid tissues.
Fleissner, Diana
Hansen, Wiebke
Geffers, Robert
Buer, Jan
Westendorf, Astrid M
Institute of Medical Microbiology, University Hospital Essen, University Duisburg-Essen, Essen, Germany.
BACKGROUND: In contrast to intestinal CD4(+) regulatory T cells (T(regs)), the generation and function of immunomodulatory intestinal CD8(+) T cells is less well defined. To dissect the immunologic mechanisms of CD8(+) T cell function in the mucosa, reactivity against hemagglutinin (HA) expressed in intestinal epithelial cells of mice bearing a MHC class-I-restricted T-cell-receptor specific for HA was studied. METHODOLOGY AND PRINCIPAL FINDINGS: HA-specific CD8(+) T cells were isolated from gut-associated tissues and phenotypically and functionally characterized for the expression of Foxp3(+) and their suppressive capacity. We demonstrate that intestinal HA expression led to peripheral induction of HA-specific CD8(+)Foxp3(+) T cells. Antigen-experienced CD8(+) T cells in this transgenic mouse model suppressed the proliferation of CD8(+) and CD4(+) T cells in vitro. Gene expression analysis of suppressive HA-specific CD8(+) T cells revealed a specific up-regulation of CD103, Nrp1, Tnfrsf9 and Pdcd1, molecules also expressed on CD4(+) T(reg) subsets. Finally, gut-associated dendritic cells were able to induce HA-specific CD8(+)Foxp3(+) T cells. CONCLUSION AND SIGNIFICANCE: We demonstrate that gut specific antigen presentation is sufficient to induce CD8(+) T(regs)in vivo which may maintain intestinal homeostasis by down-modulating effector functions of T cells.
2010-12-03T10:43:41Z
2010-12-03T10:43:41Z
2010
Article
Local induction of immunosuppressive CD8+ T cells in the gut-associated lymphoid tissues. 2010, 5 (10):e15373 PLoS ONE
1932-6203
20975955
10.1371/journal.pone.0015373
http://hdl.handle.net/10033/117075
PloS one
en
oai:repository.helmholtz-hzi.de:10033/1206292019-08-30T11:30:32Zcom_10033_6805com_10033_6799col_10033_6880
Molecular basis for the dual function of Eps8 on actin dynamics: bundling and capping.
Hertzog, Maud
Milanesi, Francesca
Hazelwood, Larnele
Disanza, Andrea
Liu, HongJun
Perlade, Emilie
Malabarba, Maria Grazia
Pasqualato, Sebastiano
Maiolica, Alessio
Confalonieri, Stefano
Le Clainche, Christophe
Offenhauser, Nina
Block, Jennifer
Rottner, Klemens
Di Fiore, Pier Paolo
Carlier, Marie-France
Volkmann, Niels
Hanein, Dorit
Scita, Giorgio
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy.
Actin capping and cross-linking proteins regulate the dynamics and architectures of different cellular protrusions. Eps8 is the founding member of a unique family of capping proteins capable of side-binding and bundling actin filaments. However, the structural basis through which Eps8 exerts these functions remains elusive. Here, we combined biochemical, molecular, and genetic approaches with electron microscopy and image analysis to dissect the molecular mechanism responsible for the distinct activities of Eps8. We propose that bundling activity of Eps8 is mainly mediated by a compact four helix bundle, which is contacting three actin subunits along the filament. The capping activity is mainly mediated by a amphipathic helix that binds within the hydrophobic pocket at the barbed ends of actin blocking further addition of actin monomers. Single-point mutagenesis validated these modes of binding, permitting us to dissect Eps8 capping from bundling activity in vitro. We further showed that the capping and bundling activities of Eps8 can be fully dissected in vivo, demonstrating the physiological relevance of the identified Eps8 structural/functional modules. Eps8 controls actin-based motility through its capping activity, while, as a bundler, is essential for proper intestinal morphogenesis of developing Caenorhabditis elegans.
2011-01-28T15:52:02Z
2011-01-28T15:52:02Z
2010
Article
Molecular basis for the dual function of Eps8 on actin dynamics: bundling and capping. 2010, 8 (6):e1000387 PLoS Biol.
1545-7885
20532239
10.1371/journal.pbio.1000387
http://hdl.handle.net/10033/120629
PLoS biology
en
oai:repository.helmholtz-hzi.de:10033/1210482019-08-30T11:36:05Zcom_10033_6805com_10033_6799col_10033_6880
The vinculin-DeltaIn20/21 mouse: characteristics of a constitutive, actin-binding deficient splice variant of vinculin.
Marg, Susanna
Winkler, Ulrike
Sestu, Marcello
Himmel, Mirko
Schönherr, Madeleine
Bär, Janina
Mann, Amrit
Moser, Markus
Mierke, Claudia T
Rottner, Klemens
Blessing, Manfred
Hirrlinger, Johannes
Ziegler, Wolfgang H
Faculty of Medicine, Interdisciplinary Centre for Clinical Research (IZKF) Leipzig, University of Leipzig, Leipzig, Germany.
The cytoskeletal adaptor protein vinculin plays a fundamental role in cell contact regulation and affects central aspects of cell motility, which are essential to both embryonal development and tissue homeostasis. Functional regulation of this evolutionarily conserved and ubiquitously expressed protein is dominated by a high-affinity, autoinhibitory head-to-tail interaction that spatially restricts ligand interactions to cell adhesion sites and, furthermore, limits the residency time of vinculin at these sites. To date, no mutants of the vinculin protein have been characterized in animal models.
2011-02-03T10:37:55Z
2011-02-03T10:37:55Z
2010
Article
The vinculin-DeltaIn20/21 mouse: characteristics of a constitutive, actin-binding deficient splice variant of vinculin. 2010, 5 (7):e11530 PLoS ONE
1932-6203
20644727
10.1371/journal.pone.0011530
http://hdl.handle.net/10033/121048
PloS one
en
oai:repository.helmholtz-hzi.de:10033/1254482019-08-30T11:27:09Zcom_10033_107102com_10033_6799col_10033_107103
Statistical modelling for data from experiments with short hairpin RNAs
Klawonn, Frank
Wüstefeld, T.
Zender, Lars
Helmholtz Center for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
2011-03-23T15:24:15Z
2011-03-23T15:24:15Z
2011-03-23T15:24:15Z
Article
03029743
http://hdl.handle.net/10033/125448
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
null
Springer
oai:repository.helmholtz-hzi.de:10033/1297602019-08-30T11:37:00Zcom_10033_6802com_10033_6799col_10033_6873
Urinary collagen fragments are significantly altered in diabetes: a link to pathophysiology.
Maahs, David M
Siwy, Justyna
Argilés, Angel
Cerna, Marie
Delles, Christian
Dominiczak, Anna F
Gayrard, Nathalie
Iphöfer, Alexander
Jänsch, Lothar
Jerums, George
Medek, Karel
Mischak, Harald
Navis, Gerjan J
Roob, Johannes M
Rossing, Kasper
Rossing, Peter
Rychlík, Ivan
Schiffer, Eric
Schmieder, Roland E
Wascher, Thomas C
Winklhofer-Roob, Brigitte M
Zimmerli, Lukas U
Zürbig, Petra
Snell-Bergeon, Janet K
Barbara Davis Center for Childhood Diabetes, University of Colorado Denver, Aurora, Colorado, United States of America. David.Maahs@ucdenver.edu
The pathogenesis of diabetes mellitus (DM) is variable, comprising different inflammatory and immune responses. Proteome analysis holds the promise of delivering insight into the pathophysiological changes associated with diabetes. Recently, we identified and validated urinary proteomics biomarkers for diabetes. Based on these initial findings, we aimed to further validate urinary proteomics biomarkers specific for diabetes in general, and particularity associated with either type 1 (T1D) or type 2 diabetes (T2D).
2011-05-18T13:44:55Z
2011-05-18T13:44:55Z
2010
Article
Urinary collagen fragments are significantly altered in diabetes: a link to pathophysiology. 2010, 5 (9) PLoS ONE
1932-6203
20927192
10.1371/journal.pone.0013051
http://hdl.handle.net/10033/129760
PloS one
en
oai:repository.helmholtz-hzi.de:10033/1369562019-08-30T11:37:00Zcom_10033_6805com_10033_6799col_10033_6880
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes.
Jackson, Ben
Peyrollier, Karine
Pedersen, Esben
Basse, Astrid
Karlsson, Richard
Wang, Zhipeng
Lefever, Tine
Ochsenbein, Alexandra M
Schmidt, Gudula
Aktories, Klaus
Stanley, Alanna
Quondamatteo, Fabio
Ladwein, Markus
Rottner, Klemens
van Hengel, Jolanda
Brakebusch, Cord
Biomedical Institute, BRIC, University of Copenhagen, 2200 Copenhagen, Denmark.
RhoA is a small guanosine-5'-triphosphatase (GTPase) suggested to be essential for cytokinesis, stress fiber formation, and epithelial cell-cell contacts. In skin, loss of RhoA was suggested to underlie pemphigus skin blistering. To analyze RhoA function in vivo, we generated mice with a keratinocyte-restricted deletion of the RhoA gene. Despite a severe reduction of cofilin and myosin light chain (MLC) phosphorylation, these mice showed normal skin development. Primary RhoA-null keratinocytes, however, displayed an increased percentage of multinucleated cells, defective maturation of cell-cell contacts. Furthermore we observed increased cell spreading due to impaired RhoA-ROCK (Rho-associated protein kinase)-MLC phosphatase-MLC-mediated cell contraction, independent of Rac1. Rho-inhibiting toxins further increased multinucleation of RhoA-null cells but had no significant effect on spreading, suggesting that RhoB and RhoC have partially overlapping functions with RhoA. Loss of RhoA decreased directed cell migration in vitro caused by reduced migration speed and directional persistence. These defects were not related to the decreased cell contraction and were independent of ROCK, as ROCK inhibition by Y27632 increased directed migration of both control and RhoA-null keratinocytes. Our data indicate a crucial role for RhoA and contraction in regulating cell spreading and a contraction-independent function of RhoA in keratinocyte migration. In addition, our data show that RhoA is dispensable for skin development.
2011-07-26T10:22:10Z
2011-07-26T10:22:10Z
2011-03
Article
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes. 2011, 22 (5):593-605 Mol. Biol. Cell
1939-4586
21209320
10.1091/mbc.E09-10-0859
http://hdl.handle.net/10033/136956
Molecular biology of the cell
en
oai:repository.helmholtz-hzi.de:10033/1326092019-08-30T11:27:44Zcom_10033_6805com_10033_6799col_10033_6880
Introduction to Small GTPases
Williams, Michael J.
Rottner, Klemens
Helmholtz Center for Infection Research, Inhoffenstr. 7, D-38124 Braunschweig, Germany
2011-06-06T09:44:56Z
2011-06-06T09:44:56Z
2010-07
Article
Introduction to Small GTPases 2010, 1 (1):1 Small GTPases
2154-1248
10.4161/sgtp.1.1.12245
http://hdl.handle.net/10033/132609
Small GTPases
http://www.landesbioscience.com/journals/smallgtpases/article/12245/
oai:repository.helmholtz-hzi.de:10033/1335722019-08-30T11:27:44Zcom_10033_6802com_10033_6799col_10033_6873
In vitro field exposition of skin cells between 100 GHz and 2.52 THz
KLeine-Ostmann, Thomas
Jastrow, Christian
Salhi, Mohamed Amine
Schrader, Thorsten
Hintzsche, Henning
Stopper, Helga
Kärst, Uwe
Heinen, B.
Baaske, Kai
Koch, M.
Helmholtz Center for Infection Research (HZI), 38124 Braunschweig, Germany.
2011-06-17T12:58:23Z
2011-06-17T12:58:23Z
2010
Article
In vitro field exposition of skin cells between 100 GHz and 2.52 THz. (2009)34th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2009, art. no. 5324695, .
978-142445417-4
10.1109/ICIMW.2009.5324695
http://hdl.handle.net/10033/133572
Conference Proceeding
IEEE
oai:repository.helmholtz-hzi.de:10033/1347622019-08-30T11:37:24Zcom_10033_6807com_10033_6799col_10033_6884
Snail regulates cell survival and inhibits cellular senescence in human metastatic prostate cancer cell lines.
Emadi Baygi, Modjtaba
Soheili, Zahra Soheila
Schmitz, Ingo
Sameie, Shahram
Schulz, Wolfgang A
Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
The epithelial-mesenchymal transition (EMT) is regarded as an important step in cancer metastasis. Snail, a master regulator of EMT, has been recently proposed to act additionally as a cell survival factor and inducer of motility. We have investigated the function of Snail (SNAI1) in prostate cancer cells by downregulating its expression via short (21-mer) interfering RNA (siRNA) and measuring the consequences on EMT markers, cell viability, death, cell cycle, senescence, attachment, and invasivity. Of eight carcinoma cell lines, the prostate carcinoma cell lines LNCaP and PC-3 showed the highest and moderate expression of SNAI1 mRNA, respectively, as measured by quantitative RT-PCR. Long-term knockdown of Snail induced a severe decline in cell numbers in LNCaP and PC-3 and caspase activity was accordingly enhanced in both cell lines. In addition, suppression of Snail expression induced senescence in LNCaP cells. SNAI1-siRNA-treated cells did not tolerate detachment from the extracellular matrix, probably due to downregulation of integrin α6. Expression of E-cadherin, vimentin, and fibronectin was also affected. Invasiveness of PC-3 cells was not significantly diminished by Snail knockdown. Our data suggest that Snail acts primarily as a survival factor and inhibitor of cellular senescence in prostate cancer cell lines. We therefore propose that Snail can act as early driver of prostate cancer progression.
2011-06-28T13:47:38Z
2011-06-28T13:47:38Z
2010-12
Article
Snail regulates cell survival and inhibits cellular senescence in human metastatic prostate cancer cell lines. 2010, 26 (6):553-67 Cell Biol. Toxicol.
1573-6822
20397042
10.1007/s10565-010-9163-5
http://hdl.handle.net/10033/134762
Cell biology and toxicology
en
oai:repository.helmholtz-hzi.de:10033/2138112019-08-30T11:37:23Zcom_10033_6805com_10033_6799col_10033_6880
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes.
Jackson, Ben
Peyrollier, Karine
Pedersen, Esben
Basse, Astrid
Karlsson, Richard
Wang, Zhipeng
Lefever, Tine
Ochsenbein, Alexandra M
Schmidt, Gudula
Aktories, Klaus
Stanley, Alanna
Quondamatteo, Fabio
Ladwein, Markus
Rottner, Klemens
van Hengel, Jolanda
Brakebusch, Cord
Biomedical Institute, BRIC, University of Copenhagen, 2200 Copenhagen, Denmark.
RhoA is a small guanosine-5'-triphosphatase (GTPase) suggested to be essential for cytokinesis, stress fiber formation, and epithelial cell-cell contacts. In skin, loss of RhoA was suggested to underlie pemphigus skin blistering. To analyze RhoA function in vivo, we generated mice with a keratinocyte-restricted deletion of the RhoA gene. Despite a severe reduction of cofilin and myosin light chain (MLC) phosphorylation, these mice showed normal skin development. Primary RhoA-null keratinocytes, however, displayed an increased percentage of multinucleated cells, defective maturation of cell-cell contacts. Furthermore we observed increased cell spreading due to impaired RhoA-ROCK (Rho-associated protein kinase)-MLC phosphatase-MLC-mediated cell contraction, independent of Rac1. Rho-inhibiting toxins further increased multinucleation of RhoA-null cells but had no significant effect on spreading, suggesting that RhoB and RhoC have partially overlapping functions with RhoA. Loss of RhoA decreased directed cell migration in vitro caused by reduced migration speed and directional persistence. These defects were not related to the decreased cell contraction and were independent of ROCK, as ROCK inhibition by Y27632 increased directed migration of both control and RhoA-null keratinocytes. Our data indicate a crucial role for RhoA and contraction in regulating cell spreading and a contraction-independent function of RhoA in keratinocyte migration. In addition, our data show that RhoA is dispensable for skin development.
2012-03-01T16:01:13Z
2012-03-01T16:01:13Z
2011-03
Article
RhoA is dispensable for skin development, but crucial for contraction and directed migration of keratinocytes. 2011, 22 (5):593-605 Mol. Biol. Cell
1939-4586
21209320
10.1091/mbc.E09-10-0859
http://hdl.handle.net/10033/213811
Molecular biology of the cell
en
oai:repository.helmholtz-hzi.de:10033/1460102019-08-30T11:25:11Zcom_10033_6807com_10033_6799col_10033_6884
Microtubules as platforms for assaying actin polymerization in vivo.
Oelkers, J Margit
Vinzenz, Marlene
Nemethova, Maria
Jacob, Sonja
Lai, Frank P L
Block, Jennifer
Szczodrak, Malgorzata
Kerkhoff, Eugen
Backert, Steffen
Schlüter, Kai
Stradal, Theresia E B
Small, J Victor
Koestler, Stefan A
Rottner, Klemens
Helmholtz Centre for Infection Research, Braunschweig, Germany.
The actin cytoskeleton is continuously remodeled through cycles of actin filament assembly and disassembly. Filaments are born through nucleation and shaped into supramolecular structures with various essential functions. These range from contractile and protrusive assemblies in muscle and non-muscle cells to actin filament comets propelling vesicles or pathogens through the cytosol. Although nucleation has been extensively studied using purified proteins in vitro, dissection of the process in cells is complicated by the abundance and molecular complexity of actin filament arrays. We here describe the ectopic nucleation of actin filaments on the surface of microtubules, free of endogenous actin and interfering membrane or lipid. All major mechanisms of actin filament nucleation were recapitulated, including filament assembly induced by Arp2/3 complex, formin and Spir. This novel approach allows systematic dissection of actin nucleation in the cytosol of live cells, its genetic re-engineering as well as screening for new modifiers of the process.
2011-10-19T13:44:11Z
2011-10-19T13:44:11Z
2011
Article
Microtubules as platforms for assaying actin polymerization in vivo. 2011, 6 (5):e19931 PLoS ONE
1932-6203
21603613
10.1371/journal.pone.0019931
http://hdl.handle.net/10033/146010
PloS one
en
oai:repository.helmholtz-hzi.de:10033/1963292019-08-30T11:25:43Zcom_10033_6807com_10033_6799col_10033_6884
High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1.
Linkner, Joern
Witte, Gregor
Stradal, Theresia
Curth, Ute
Faix, Jan
Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany.
The Scar/WAVE-complex links upstream Rho-GTPase signaling to the activation of the conserved Arp2/3-complex. Scar/WAVE-induced and Arp2/3-complex-mediated actin nucleation is crucial for actin assembly in protruding lamellipodia to drive cell migration. The heteropentameric Scar/WAVE-complex is composed of Scar/WAVE, Abi, Nap, Pir and a small polypeptide Brk1/HSPC300, and recent work suggested that free Brk1 serves as a homooligomeric precursor in the assembly of this complex. Here we characterized the Brk1 trimer from Dictyostelium by analytical ultracentrifugation and gelfiltration. We show for the first time its dissociation at concentrations in the nanomolar range as well as an exchange of subunits within different DdBrk1 containing complexes. Moreover, we determined the three-dimensional structure of DdBrk1 at 1.5 Å resolution by X-ray crystallography. Three chains of DdBrk1 are associated with each other forming a parallel triple coiled-coil bundle. Notably, this structure is highly similar to the heterotrimeric α-helical bundle of HSPC300/WAVE1/Abi2 within the human Scar/WAVE-complex. This finding, together with the fact that Brk1 is collectively sandwiched by the remaining subunits and also constitutes the main subunit connecting the triple-coil domain of the HSPC300/WAVE1/Abi2/ heterotrimer to Sra1(Pir1), implies a critical function of this subunit in the assembly process of the entire Scar/WAVE-complex.
2011-12-07T15:36:57Z
2011-12-07T15:36:57Z
2011
Article
High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1. 2011, 6 (6):e21327 PLoS ONE
1932-6203
21701600
10.1371/journal.pone.0021327
http://hdl.handle.net/10033/196329
PloS one
en
oai:repository.helmholtz-hzi.de:10033/2008892019-08-30T11:31:49Zcom_10033_6807com_10033_6799col_10033_6884
Theoretical model for cellular shapes driven by protrusive and adhesive forces.
Kabaso, Doron
Shlomovitz, Roie
Schloen, Kathrin
Stradal, Theresia
Gov, Nir S
Department of Chemical Physics, The Weizmann Institute of Science, Rehovot, Israel.
The forces that arise from the actin cytoskeleton play a crucial role in determining the cell shape. These include protrusive forces due to actin polymerization and adhesion to the external matrix. We present here a theoretical model for the cellular shapes resulting from the feedback between the membrane shape and the forces acting on the membrane, mediated by curvature-sensitive membrane complexes of a convex shape. In previous theoretical studies we have investigated the regimes of linear instability where spontaneous formation of cellular protrusions is initiated. Here we calculate the evolution of a two dimensional cell contour beyond the linear regime and determine the final steady-state shapes arising within the model. We find that shapes driven by adhesion or by actin polymerization (lamellipodia) have very different morphologies, as observed in cells. Furthermore, we find that as the strength of the protrusive forces diminish, the system approaches a stabilization of a periodic pattern of protrusions. This result can provide an explanation for a number of puzzling experimental observations regarding cellular shape dependence on the properties of the extra-cellular matrix.
2012-01-09T10:43:20Z
2012-01-09T10:43:20Z
2011-05
Article
Theoretical model for cellular shapes driven by protrusive and adhesive forces. 2011, 7 (5):e1001127 PLoS Comput. Biol.
1553-7358
21573201
10.1371/journal.pcbi.1001127
http://hdl.handle.net/10033/200889
PLoS computational biology
en
oai:repository.helmholtz-hzi.de:10033/2094532021-08-04T14:12:49Zcom_10033_6805com_10033_6799col_10033_6880
Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo.
Schnoor, Michael
Lai, Frank P L
Zarbock, Alexander
Kläver, Ruth
Polaschegg, Christian
Schulte, Dörte
Weich, Herbert A
Oelkers, J Margit
Rottner, Klemens
Vestweber, Dietmar
Max Planck Institute for Molecular Biomedicine, D 48149 Münster, Germany.
Neutrophil extravasation and the regulation of vascular permeability require dynamic actin rearrangements in the endothelium. In this study, we analyzed in vivo whether these processes require the function of the actin nucleation-promoting factor cortactin. Basal vascular permeability for high molecular weight substances was enhanced in cortactin-deficient mice. Despite this leakiness, neutrophil extravasation in the tumor necrosis factor-stimulated cremaster was inhibited by the loss of cortactin. The permeability defect was caused by reduced levels of activated Rap1 (Ras-related protein 1) in endothelial cells and could be rescued by activating Rap1 via the guanosine triphosphatase (GTPase) exchange factor EPAC (exchange protein directly activated by cAMP). The defect in neutrophil extravasation was caused by enhanced rolling velocity and reduced adhesion in postcapillary venules. Impaired rolling interactions were linked to contributions of β(2)-integrin ligands, and firm adhesion was compromised by reduced ICAM-1 (intercellular adhesion molecule 1) clustering around neutrophils. A signaling process known to be critical for the formation of ICAM-1-enriched contact areas and for transendothelial migration, the ICAM-1-mediated activation of the GTPase RhoG was blocked in cortactin-deficient endothelial cells. Our results represent the first physiological evidence that cortactin is crucial for orchestrating the molecular events leading to proper endothelial barrier function and leukocyte recruitment in vivo.
2012-02-06T14:40:51Z
2012-02-06T14:40:51Z
2011-08-01
Article
Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo. 2011, 208 (8):1721-35 J. Exp. Med.
1540-9538
21788407
10.1084/jem.20101920
http://hdl.handle.net/10033/209453
The Journal of experimental medicine
en
oai:repository.helmholtz-hzi.de:10033/2106692019-08-30T11:29:17Zcom_10033_107102com_10033_6799col_10033_107103
The promoter of human telomerase reverse transcriptase is activated during liver regeneration and hepatocyte proliferation.
Sirma, Hüseyin
Kumar, Mukesh
Meena, Jitendra K
Witt, Britta
Weise, Julia M
Lechel, Andre
Ande, Satyanarayana
Sakk, Vadim
Guguen-Guillouzo, Christiane
Zender, Lars
Rudolph, Karl-Lenhard
Günes, Cagatay
Heinrich-Pette-Institute, Hamburg, Germany.
Telomerase activity has not been detected in healthy human liver biopsy samples, but it is up-regulated in most human liver tumors. It is not clear whether telomerase is activated in response to acute or chronic liver injury. Telomerase activity is closely associated with expression of its catalytic subunit, telomerase reverse transcriptase (TERT). We analyzed the activity of the human TERT (hTERT) promoter during liver regeneration in vivo and hepatocyte proliferation in vitro.
2012-02-14T10:14:50Z
2012-02-14T10:14:50Z
2011-07
Article
The promoter of human telomerase reverse transcriptase is activated during liver regeneration and hepatocyte proliferation. 2011, 141 (1):326-37, 337.e1-3 Gastroenterology
1528-0012
21447332
10.1053/j.gastro.2011.03.047
http://hdl.handle.net/10033/210669
Gastroenterology
en
oai:repository.helmholtz-hzi.de:10033/2183772019-08-30T11:34:48Zcom_10033_6807com_10033_6799col_10033_6884
Essential role for Abi1 in embryonic survival and WAVE2 complex integrity.
Dubielecka, Patrycja M
Ladwein, Kathrin I
Xiong, Xiaoling
Migeotte, Isabelle
Chorzalska, Anna
Anderson, Kathryn V
Sawicki, Janet A
Rottner, Klemens
Stradal, Theresia E
Kotula, Leszek
Laboratory of Cell Signaling, New York Blood Center, New York, NY 10065, USA.
Abl interactor 1 (Abi1) plays a critical function in actin cytoskeleton dynamics through participation in the WAVE2 complex. To gain a better understanding of the specific role of Abi1, we generated a conditional Abi1-KO mouse model and MEFs lacking Abi1 expression. Abi1-KO cells displayed defective regulation of the actin cytoskeleton, and this dysregulation was ascribed to altered activity of the WAVE2 complex. Changes in motility of Abi1-KO cells were manifested by a decreased migration rate and distance but increased directional persistence. Although these phenotypes did not correlate with peripheral ruffling, which was unaffected, Abi1-KO cells exhibited decreased dorsal ruffling. Western blotting analysis of Abi1-KO cell lysates indicated reduced levels of the WAVE complex components WAVE1 and WAVE2, Nap1, and Sra-1/PIR121. Although relative Abi2 levels were more than doubled in Abi1-KO cells, the absolute Abi2 expression in these cells amounted only to a fifth of Abi1 levels in the control cell line. This finding suggests that the presence of Abi1 is critical for the integrity and stability of WAVE complex and that Abi2 levels are not sufficiently increased to compensate fully for the loss of Abi1 in KO cells and to restore the integrity and function of the WAVE complex. The essential function of Abi1 in WAVE complexes and their regulation might explain the observed embryonic lethality of Abi1-deficient embryos, which survived until approximately embryonic day 11.5 and displayed malformations in the developing heart and brain. Cells lacking Abi1 and the conditional Abi1-KO mouse will serve as critical models for defining Abi1 function.
2012-04-13T13:42:12Z
2012-04-13T13:42:12Z
2011-04-26
Article
Essential role for Abi1 in embryonic survival and WAVE2 complex integrity. 2011, 108 (17):7022-7 Proc. Natl. Acad. Sci. U.S.A.
1091-6490
21482783
10.1073/pnas.1016811108
http://hdl.handle.net/10033/218377
Proceedings of the National Academy of Sciences of the United States of America
en
Archived with thanks to Proceedings of the National Academy of Sciences of the United States of America
oai:repository.helmholtz-hzi.de:10033/2422972019-08-30T11:27:46Zcom_10033_107102com_10033_6799col_10033_107103
Immune surveillance of senescent cells--biological significance in cancer- and non-cancer pathologies.
Hoenicke, Lisa
Zender, Lars
Helmholtz Centre for Infection Research, Braunschweig, Germany.
Cellular senescence, a state of stable growth arrest, can occur in response to various stress stimuli such as telomere shortening, treatment with chemotherapeutic drugs or the aberrant activation of oncogenes. Senescent cells communicate with their environment by secreting various cytokines and growth factors, and it has become clear that this 'secretory phenotype' can have pro- as well as anti-tumorigenic effects. Recent work from our laboratory showed that premalignant, senescent hepatocytes are recognized and cleared through an antigen-specific immune response and that this immune response, designated as 'senescence surveillance' is crucial for tumor suppression in the liver [(Kang,T.W. et al. (2011) Senescence surveillance of pre-malignant hepatocytes limits liver cancer development. Nature, 479, 547-551]. It is an emerging concept that immune responses against senescent cells have a broader biological significance in cancer- as well as non-cancer pathologies and current data suggest that distinct immune responses are engaged to clear senescent cells in different disease settings. In this review article, we will discuss different examples how immune responses against senescent cells are involved to restrict disease progression in cancer- and non-cancer pathologies.
2012-09-10T13:45:39Z
2012-09-10T13:45:39Z
2012-06
Article
Immune surveillance of senescent cells--biological significance in cancer- and non-cancer pathologies. 2012, 33 (6):1123-6 Carcinogenesis
1460-2180
22470164
10.1093/carcin/bgs124
http://hdl.handle.net/10033/242297
Carcinogenesis
en
Archived with thanks to Carcinogenesis
oai:repository.helmholtz-hzi.de:10033/2712922019-08-30T11:26:13Zcom_10033_107102com_10033_6799col_10033_107103
A cluster of cooperating tumor-suppressor gene candidates in chromosomal deletions.
Xue, Wen
Kitzing, Thomas
Roessler, Stephanie
Zuber, Johannes
Krasnitz, Alexander
Schultz, Nikolaus
Revill, Kate
Weissmueller, Susann
Rappaport, Amy R
Simon, Janelle
Zhang, Jack
Luo, Weijun
Hicks, James
Zender, Lars
Wang, Xin Wei
Powers, Scott
Wigler, Michael
Lowe, Scott W
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
The large chromosomal deletions frequently observed in cancer genomes are often thought to arise as a "two-hit" mechanism in the process of tumor-suppressor gene (TSG) inactivation. Using a murine model system of hepatocellular carcinoma (HCC) and in vivo RNAi, we test an alternative hypothesis, that such deletions can arise from selective pressure to attenuate the activity of multiple genes. By targeting the mouse orthologs of genes frequently deleted on human 8p22 and adjacent regions, which are lost in approximately half of several other major epithelial cancers, we provide evidence suggesting that multiple genes on chromosome 8p can cooperatively inhibit tumorigenesis in mice, and that their cosuppression can synergistically promote tumor growth. In addition, in human HCC patients, the combined down-regulation of functionally validated 8p TSGs is associated with poor survival, in contrast to the down-regulation of any individual gene. Our data imply that large cancer-associated deletions can produce phenotypes distinct from those arising through loss of a single TSG, and as such should be considered and studied as distinct mutational events.
2013-03-06T09:03:42Z
2013-03-06T09:03:42Z
2012-05-22
Article
A cluster of cooperating tumor-suppressor gene candidates in chromosomal deletions. 2012, 109 (21):8212-7 Proc. Natl. Acad. Sci. U.S.A.
1091-6490
22566646
10.1073/pnas.1206062109
http://hdl.handle.net/10033/271292
Proceedings of the National Academy of Sciences of the United States of America
en
Archived with thanks to Proceedings of the National Academy of Sciences of the United States of America
oai:repository.helmholtz-hzi.de:10033/2788742019-08-30T11:30:58Zcom_10033_6802com_10033_6799col_10033_6873
Minimal increase in genetic diversity enhances predation resistance.
Koh, Kai S
Matz, Carsten
Tan, Chuan H
LE, Hoang L
Rice, Scott A
Marshall, Dustin J
Steinberg, Peter D
Kjelleberg, Staffan
Centre for Marine Bio-Innovation, University of New South Wales, Sydney, NSW, Australia School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.
The importance of species diversity to emergent, ecological properties of communities is increasingly appreciated, but the importance of within-species genetic diversity for analogous emergent properties of populations is only just becoming apparent. Here, the properties and effects of genetic variation on predation resistance in populations were assessed and the molecular mechanism underlying these emergent effects was investigated. Using biofilms of the ubiquitous bacterium Serratia marcescens, we tested the importance of genetic diversity in defending biofilms against protozoan grazing, a main source of mortality for bacteria in all natural ecosystems. S. marcescens biofilms established from wild-type cells produce heritable, stable variants, which when experimentally combined, persist as a diverse assemblage and are significantly more resistant to grazing than either wild type or variant biofilms grown in monoculture. This diversity effect is biofilm-specific, a result of either facilitation or resource partitioning among variants, with equivalent experiments using planktonic cultures and grazers resulting in dominance by a single resistant strain. The variants studied are all the result of single nucleotide polymorphisms in one regulatory gene suggesting that the benefits of genetic diversity in clonal biofilms can occur through remarkably minimal genetic change. The findings presented here provide a new insight on the integration of genetics and population ecology, in which diversity arising through minimal changes in genotype can have major ecological implications for natural populations.
2013-04-04T08:35:00Z
2013-04-04T08:35:00Z
2012-04
Article
Minimal increase in genetic diversity enhances predation resistance. 2012, 21 (7):1741-53 Mol. Ecol.
1365-294X
22211530
10.1111/j.1365-294X.2011.05415.x
http://hdl.handle.net/10033/278874
Molecular ecology
en
Archived with thanks to Molecular ecology
oai:repository.helmholtz-hzi.de:10033/3025012019-08-30T11:36:59Zcom_10033_6805com_10033_6799col_10033_6880
Cytotoxic necrotizing factor-y boosts yersinia effector translocation by activating rac protein.
Wolters, Manuel
Boyle, Erin C
Lardong, Kerstin
Trülzsch, Konrad
Steffen, Anika
Rottner, Klemens
Ruckdeschel, Klaus
Aepfelbacher, Martin
From the Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
Pathogenic Yersinia spp. translocate the effectors YopT, YopE, and YopO/YpkA into target cells to inactivate Rho family GTP-binding proteins and block immune responses. Some Yersinia spp. also secrete the Rho protein activator cytotoxic necrotizing factor-Y (CNF-Y), but it has been unclear how the bacteria may benefit from Rho protein activation. We show here that CNF-Y increases Yop translocation in Yersinia enterocolitica-infected cells up to 5-fold. CNF-Y strongly activated RhoA and also delayed in time Rac1 and Cdc42, but when individually expressed, constitutively active mutants of Rac1, but not of RhoA, increased Yop translocation. Consistently, knock-out or knockdown of Rac1 but not of RhoA, -B, or -C inhibited Yersinia effector translocation in CNF-Y-treated and control cells. Activation or knockdown of Cdc42 also affected Yop translocation but much less efficiently than Rac. The increase in Yop translocation induced by CNF-Y was essentially independent of the presence of YopE, YopT, or YopO in the infecting Yersinia strain, indicating that none of the Yops reported to inhibit translocation could reverse the CNF-Y effect. In summary, the CNF-Y activity of Yersinia strongly enhances Yop translocation through activation of Rac.
2013-09-30T08:44:15Z
2013-09-30T08:44:15Z
2013-08-09
Article
Cytotoxic necrotizing factor-y boosts yersinia effector translocation by activating rac protein. 2013, 288 (32):23543-53 J. Biol. Chem.
1083-351X
23803609
10.1074/jbc.M112.448662
http://hdl.handle.net/10033/302501
The Journal of biological chemistry
en
Archived with thanks to The Journal of biological chemistry
oai:repository.helmholtz-hzi.de:10033/3046022019-08-30T11:37:00Zcom_10033_6805com_10033_6799col_10033_6880
Arp2/3 complex is essential for actin network treadmilling as well as for targeting of capping protein and cofilin.
Koestler, Stefan A
Steffen, Anika
Nemethova, Maria
Winterhoff, Moritz
Luo, Ningning
Holleboom, J Margit
Krupp, Jessica
Jacob, Sonja
Vinzenz, Marlene
Schur, Florian
Schlüter, Kai
Gunning, Peter W
Winkler, Christoph
Schmeiser, Christian
Faix, Jan
Stradal, Theresia E B
Small, J Victor
Rottner, Klemens
Institute of Genetics, University of Bonn, D-53115 Bonn, Germany Institute of Molecular Biotechnology, Austrian Academy of Sciences, A-1030 Vienna, Austria Johann Radon Institute for Computational and Applied Mathematics, Austrian Academy of Sciences, A-1030 Vienna, Austria Institute for Biophysical Chemistry, Hannover Medical School, D-30625 Hannover, Germany Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany Institute for Molecular Cell Biology, University of Münster, D-48149 Münster, Germany Oncology Research Unit, School of Medical Sciences, University of New South Wales, Sydney 2052, Australia Faculty of Mathematics, University of Vienna, A-1090 Vienna, Austria.
Lamellipodia are sheet-like protrusions formed during migration or phagocytosis and comprise a network of actin filaments. Filament formation in this network is initiated by nucleation/branching through the actin-related protein 2/3 (Arp2/3) complex downstream of its activator, suppressor of cAMP receptor/WASP-family verprolin homologous (Scar/WAVE), but the relative relevance of Arp2/3-mediated branching versus actin filament elongation is unknown. Here we use instantaneous interference with Arp2/3 complex function in live fibroblasts with established lamellipodia. This allows direct examination of both the fate of elongating filaments upon instantaneous suppression of Arp2/3 complex activity and the consequences of this treatment on the dynamics of other lamellipodial regulators. We show that Arp2/3 complex is an essential organizer of treadmilling actin filament arrays but has little effect on the net rate of actin filament turnover at the cell periphery. In addition, Arp2/3 complex serves as key upstream factor for the recruitment of modulators of lamellipodia formation such as capping protein or cofilin. Arp2/3 complex is thus decisive for filament organization and geometry within the network not only by generating branches and novel filament ends, but also by directing capping or severing activities to the lamellipodium. Arp2/3 complex is also crucial to lamellipodia-based migration of keratocytes.
2013-10-24T14:19:15Z
2013-10-24T14:19:15Z
2013-09
Article
Arp2/3 complex is essential for actin network treadmilling as well as for targeting of capping protein and cofilin. 2013, 24 (18):2861-75 Mol. Biol. Cell
1939-4586
23885122
10.1091/mbc.E12-12-0857
http://hdl.handle.net/10033/304602
Molecular biology of the cell
en
Archived with thanks to Molecular biology of the cell
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