• 22nd European Society for Animal Cell Technology (ESACT) Meeting on Cell Based Technologies Vienna, Austria. 15-18 May 2011. Abstracts.

      Hauser, Hansjörg; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2011-11-22)
    • Are resorbable implants about to become a reality?

      Peuster, Matthias; Beerbaum, Phillip; Bach, Friedrich-Wilhelm; Hauser, Hansjoerg; Clinic for Congenital Heart Defects and Cardiovascular Implant Research Unit, Heart and Diabetes Center, Ruhr-University Bochum, Bad Oeynhausen, Germany. mpeuster@hdz-nrw.de (2006-04)
    • Assessment of cellular reactions to magnesium as implant 
material in comparison to titanium and to glyconate using 
the mouse tail model.

      Reifenrath, Janin; Badar, Muhammad; Dziuba, Dina; Müller, Peter P; Heidenblut, Torsten; Bondarenko, Alexander; Meyer-Lindenberg, Andrea; Small Animal Clinic, University of Veterinary Medicine Hannover, Hannover - Germany. (2013)
      Nowadays, research in magnesium alloys as a biodegradable implant material has increased. The aim of this study was to examine osteoinductive properties and tissue responses to pure magnesium in comparison to conventional permanent (titanium) and to degradable (glyconate) implant materials.
    • Bimodal and hysteretic expression in mammalian cells from a synthetic gene circuit.

      May, Tobias; Eccleston, Lee; Herrmann, Sabrina; Hauser, Hansjörg; Goncalves, Jorge; Wirth, Dagmar; Department of Gene Regulation and Differentiation, Helmholtz Centre for Infection Research, Braunschweig, Germany. (2008)
      In order to establish cells and organisms with predictable properties, synthetic biology makes use of controllable, synthetic genetic devices. These devices are used to replace or to interfere with natural pathways. Alternatively, they may be interlinked with endogenous pathways to create artificial networks of higher complexity. While these approaches have been already successful in prokaryotes and lower eukaryotes, the implementation of such synthetic cassettes in mammalian systems and even animals is still a major obstacle. This is mainly due to the lack of methods that reliably and efficiently transduce synthetic modules without compromising their regulation properties. To pave the way for implementation of synthetic regulation modules in mammalian systems we utilized lentiviral transduction of synthetic modules. A synthetic positive feedback loop, based on the Tetracycline regulation system was implemented in a lentiviral vector system and stably integrated in mammalian cells. This gene regulation circuit yields a bimodal expression response. Based on experimental data a mathematical model based on stochasticity was developed which matched and described the experimental findings. Modelling predicted a hysteretic expression response which was verified experimentally. Thereby supporting the idea that the system is driven by stochasticity. The results presented here highlight that the combination of three independent tools/methodologies facilitate the reliable installation of synthetic gene circuits with predictable expression characteristics in mammalian cells and organisms.
    • Bridging the species divide: transgenic mice humanized for type-I interferon response.

      Harari, Daniel; Abramovich, Renne; Zozulya, Alla; Smith, Paul; Pouly, Sandrine; Köster, Mario; Hauser, Hansjörg; Schreiber, Gideon (2014)
      We have generated transgenic mice that harbor humanized type I interferon receptors (IFNARs) enabling the study of type I human interferons (Hu-IFN-Is) in mice. These "HyBNAR" (Hybrid IFNAR) mice encode transgenic variants of IFNAR1 and IFNAR2 with the human extracellular domains being fused to transmembrane and cytoplasmic segments of mouse sequence. B16F1 mouse melanoma cells harboring the HyBNAR construct specifically bound Hu-IFN-Is and were rendered sensitive to Hu-IFN-I stimulated anti-proliferation, STAT1 activation and activation of a prototypical IFN-I response gene (MX2). HyBNAR mice were crossed with a transgenic strain expressing the luciferase reporter gene under the control of the IFN-responsive MX2 promoter (MX2-Luciferase). Both the HyBNAR and HyBNAR/MX2-Luciferase mice were responsive to all Hu-IFN-Is tested, inclusive of IFNα2A, IFNβ, and a human superagonist termed YNSα8. The mice displayed dose-dependent pharmacodynamic responses to Hu-IFN-I injection, as assessed by measuring the expression of IFN-responsive genes. Our studies also demonstrated a weak activation of endogenous mouse interferon response, especially after high dose administration of Hu-IFNs. In sharp contrast to data published for humans, our pharmacodynamic readouts demonstrate a very short-lived IFN-I response in mice, which is not enhanced by sub-cutaneous (SC) injections in comparison to other administration routes. With algometric differences between humans and mice taken into account, the HyBNAR mice provides a convenient non-primate pre-clinical model to advance the study of human IFN-Is.
    • Caveolin-1 influences human influenza A virus (H1N1) multiplication in cell culture.

      Sun, Lijing; Hemgård, Gun-Viol; Susanto, Sony A; Wirth, Manfred; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2010)
      The threat of recurring influenza pandemics caused by new viral strains and the occurrence of escape mutants necessitate the search for potent therapeutic targets. The dependence of viruses on cellular factors provides a weak-spot in the viral multiplication strategy and a means to interfere with viral multiplication.
    • Caveolin-1 interacts with the Gag precursor of murine leukaemia virus and modulates virus production.

      Yu, Zheng; Beer, Christiane; Koester, Mario; Wirth, Manfred (2006)
      BACKGROUND: Retroviral Gag determines virus assembly at the plasma membrane and the formation of virus-like particles in intracellular multivesicular bodies. Thereby, retroviruses exploit by interaction with cellular partners the cellular machineries for vesicular transport in various ways. RESULTS: The retroviral Gag precursor protein drives assembly of murine leukaemia viruses (MLV) at the plasma membrane (PM) and the formation of virus like particles in multivesicular bodies (MVBs). In our study we show that caveolin-1 (Cav-1), a multifunctional membrane-associated protein, co-localizes with Gag in a punctate pattern at the PM of infected NIH 3T3 cells. We provide evidence that Cav-1 interacts with the matrix protein (MA) of the Gag precursor. This interaction is mediated by a Cav-1 binding domain (CBD) within the N-terminus of MA. Interestingly, the CBD motif identified within MA is highly conserved among most other gamma-retroviruses. Furthermore, Cav-1 is incorporated into MLV released from NIH 3T3 cells. Overexpression of a GFP fusion protein containing the putative CBD of the retroviral MA resulted in a considerable decrease in production of infectious retrovirus. Moreover, expression of a dominant-negative Cav-1 mutant affected retroviral titres significantly. CONCLUSION: This study demonstrates that Cav-1 interacts with MLV Gag, co-localizes with Gag at the PM and affects the production of infectious virus. The results strongly suggest a role for Cav-1 in the process of virus assembly.
    • Characterisation of bovine leukocyte Ig-like receptors.

      Hogan, Louise; Bhuju, Sabin; Jones, Des C; Laing, Ken; Trowsdale, John; Butcher, Philip; Singh, Mahavir; Vordermeier, Martin; Allen, Rachel L; Centre for Infection, Division of Clinical Sciences, St George's, University of London, Cranmer Terrace, London, United Kingdom. p0904768@sgul.ac.uk (2012)
      Leukocyte Immunoglobulin-like receptors (LILR) are innate immune receptors involved in regulating both innate and adaptive immune functions. LILR show more interspecies conservation than the closely related Killer Ig-like receptors, and homologues have been identified in rodents, primates, seals and chickens. The murine equivalents, paired Ig-like receptors (PIR), contain two additional immunoglobulin domains, but show strong sequence and functional similarities to human LILR. The bovine genome was recently sequenced, with preliminary annotations indicating that LILR were present in this species. We therefore sought to identify and characterize novel LILR within the Bos taurus genome, compare these phylogenetically with LILR from other species and determine whether they were expressed in vivo. Twenty six potential bovine LILR were initially identified using BLAST and BLAT software. Phylogenetic analysis constructed using the neighbour-joining method, incorporating pairwise deletion and confidence limits estimated from 1000 replicates using bootstrapping, indicated that 16 of these represent novel bovine LILR. Protein structures defined using protein BLAST predict that the bovine LILR family comprises seven putative inhibitory, four activating and five soluble receptors. Preliminary expression analysis was performed by mapping the predicted sequences with raw data from total transcript sequence generated using Genome Analyzer IIx (Illumina) to provide evidence that all 16 of these receptors are expressed in vivo. The bovine receptor family appears to contain receptors which resemble the six domain rodent PIR as well as the four domain LILR found in other species.
    • Combining genetic circuit and microbial growth Kinetic models: Achallenge for biological modelling

      Koutinas, Michalis; Kiparissides, Alexandros; Lam, Ming-Chi; Silva-Rocha, Rafael; Martins dos Santos, Vítor A P; Pistikopoulos, Estradios N.; Mantalaris, Athanasios; Helmholtz Center for Infection Research, Chemical Microbiology, Inhoffenstrasse 7, 38124 Braunschweig, Germany. (Elsevier B.V., 2010)
    • Comparison of in vitro and in vivo protein release from hydrogel systems.

      Wöhl-Bruhn, Stefanie; Badar, Muhammad; Bertz, Andreas; Tiersch, Brigitte; Koetz, Joachim; Menzel, Henning; Mueller, Peter P; Bunjes, Heike; Technische Universität Braunschweig, Institute of Pharmaceutical Technology, Mendelssohnstraße 1, 38106 Braunschweig, Germany. (2012-08-20)
      Hydrogel systems based on hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA) or hydroxyethyl starch methacrylate (HES-MA) were used to assess the protein release behavior. Here, we analyzed the in vitro release of FITC-anti-human antibodies incorporated in either HES-P(EG)(6)MA or HES-MA hydrogel delivery systems in PBS or human serum. In addition, hydrogel disks and microparticles prepared from the two polymers were subcutaneously implanted in BALB/c mice. The in vivo release of FITC-IgG was non-invasively monitored by an in vivo imaging system (IVIS 200) over a time period of up to 3 months. The imaging system allowed to asses individual animals over time, therefore only a small number of animals was required to obtain high quality data. The reduction in fluorescence intensity at the site of administration was compared to in vitro release profiles. These investigations demonstrated a sustained release from HES-MA hydrogel disks compared to rapidly degrading HES-P(EG)(6)MA disks and microparticles. The sustained release from HES-MA disks could be further optimized by using increased polymer concentrations. Human serum as in vitro release medium reflected better the in vivo release from HES-P(EG)(6)MA systems than PBS, suggesting that the presence of organic substances like proteins or lipids may play a significant role for the release kinetics.
    • Control of smooth muscle cell proliferation by ferrous iron.

      Mueller, Peter P; May, Tobias; Perz, Angela; Hauser, Hansjörg; Peuster, Matthias (2006-04-01)
      This study was conducted to determine the interaction of individual corrosion products from biodegradable iron stents with cells from the adjacent tissue. The response of human umbilical venous smooth muscle cells (SMCs) to an excess of ferrous ions was investigated in a cell culture model at the phenotypic and at the molecular level. When soluble ferrous ions were added to the cell culture medium the cell growth rate was reduced. Gene expression profiling indicated a reduction in the amounts of mRNA from genes that are required for cell proliferation. In addition, mRNA was regulated from multiple genes involved in iron homeostasis, DNA replication and lipid metabolism. In conclusion, ions released from iron stents could reduce the vascular SMC proliferation rate by influencing growth-related gene expression and may therefore play a beneficial role in antagonizing restenosis in vivo.
    • Directing neuronal cell growth on implant material surfaces by microstructuring.

      Reich, Uta; Fadeeva, Elena; Warnecke, Athanasia; Paasche, Gerrit; Müller, Peter; Chichkov, Boris; Stöver, Timo; Lenarz, Thomas; Reuter, Günter; Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, Hannover, Germany. (2012-05)
      For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum. Silicone surfaces were structured by two different methods, either directly, by laser ablation or indirectly, by imprinting using laser-microstructured molds. The influence of surface structuring on neurite outgrowth was investigated utilizing a neuronal-like cell line and primary auditory neurons. The pheochromocytoma cell line PC-12 and primary spiral ganglion cells were cultured on microstructured auditory implant materials. The orientation of neurite outgrowth relative to the microgrooves was determined. Both cell types showed a preferred orientation in parallel to the microstructures on both, platinum and on molded silicone elastomer. Interestingly, microstructures generated by direct laser ablation of silicone did not influence the orientation of either cell type. This shows that differences in the manufacturing procedures can affect the ability of microstructured implant surfaces to guide the growth of neurites. This is of particular importance for clinical applications, since the molding technique represents a reproducible, economic, and commercially feasible manufacturing procedure for the microstructured silicone surfaces of medical implants.
    • DNA methylation regulates expression of VEGF-R2 (KDR) and VEGF-R3 (FLT4)

      Quentmeier, Hilmar; Eberth, Sonja; Romani, Julia; Weich, Herbert A; Zaborski, Margarete; Drexler, Hans G (2012-01-17)
      Abstract Background Vascular Endothelial Growth Factors (VEGFs) and their receptors (VEGF-Rs) are important regulators for angiogenesis and lymphangiogenesis. VEGFs and VEGF-Rs are not only expressed on endothelial cells but also on various subtypes of solid tumors and leukemias contributing to the growth of the malignant cells. This study was performed to examine whether VEGF-R2 (KDR) and VEGF-R3 (FLT4) are regulated by DNA methylation. Methods Real-time (RT) PCR analysis was performed to quantify KDR and FLT4 expression in some ninety leukemia/lymphoma cell lines, human umbilical vein endothelial cells (HUVECs) and dermal microvascular endothelial cells (HDMECs). Western blot analyses and flow cytometric analyses confirmed results at the protein level. After bisulfite conversion of DNA we determined the methylation status of KDR and FLT4 by DNA sequencing and by methylation specific PCR (MSP). Western blot analyses were performed to examine the effect of VEGF-C on p42/44 MAPK activation. Results Expression of KDR and FLT4 was observed in cell lines from various leukemic entities, but not in lymphoma cell lines: 16% (10/62) of the leukemia cell lines expressed KDR, 42% (27/65) were FLT4 positive. None of thirty cell lines representing six lymphoma subtypes showed more than marginal expression of KDR or FLT4. Western blot analyses confirmed KDR and FLT4 protein expression in HDMECs, HUVECs and in cell lines with high VEGF-R mRNA levels. Mature VEGF-C induced p42/44 MAPK activation in the KDR- /FLT4+ cell line OCI-AML1 verifying the model character of this cell line for VEGF-C signal transduction studies. Bisulfite sequencing and MSP revealed that GpG islands in the promoter regions of KDR and FLT4 were unmethylated in HUVECs, HDMECs and KDR + and FLT4 + cell lines, whereas methylated cell lines did not express these genes. In hypermethylated cell lines, KDR and FLT4 were re-inducible by treatment with the DNA demethylating agent 5-Aza-2'deoxycytidine, confirming epigenetic regulation of both genes. Conclusions Our data show that VEGF-Rs KDR and FLT4 are silenced by DNA methylation. However, if the promoters are unmethylated, other factors (e.g. transactivation factors) determine the extent of KDR and FLT4 expression.
    • DNA methylation regulates expression of VEGF-R2 (KDR) and VEGF-R3 (FLT4).

      Quentmeier, Hilmar; Eberth, Sonja; Romani, Julia; Weich, Herbert A; Zaborski, Margarete; Drexler, Hans G; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2012-01-17)
      Vascular Endothelial Growth Factors (VEGFs) and their receptors (VEGF-Rs) are important regulators for angiogenesis and lymphangiogenesis. VEGFs and VEGF-Rs are not only expressed on endothelial cells but also on various subtypes of solid tumors and leukemias contributing to the growth of the malignant cells. This study was performed to examine whether VEGF-R2 (KDR) and VEGF-R3 (FLT4) are regulated by DNA methylation.
    • Efficacy of nanoporous silica coatings on middle ear prostheses as a delivery system for antibiotics: an animal study in rabbits.

      Lensing, Rebecca; Bleich, André; Smoczek, Anna; Glage, Silke; Ehlert, Nina; Luessenhop, Tammo; Behrens, Peter; Müller, Peter Paul; Kietzmann, Manfred; Stieve, Martin; Department of Otolaryngology, Hannover Medical School, Hannover, Germany. Lensing.Rebecca@mh-hannover.de (2013-01)
      Nanoporous silica layers are able to host molecules and release them over a certain period of time. These local drug delivery systems for antibiotics could be a new approach in the treatment of chronic otitis media. The aim of this study was to examine the efficacy of nanoporous silica coatings on middle ear prostheses as a delivery system for antibiotics in vivo. Pseudomonas aeruginosa was inoculated into the middle ear of rabbits to induce an otitis media. The control group received coated Bioverit®II implants without antibiotics. Coated prostheses with loaded ciprofloxacin were implanted into the middle ears of the study group. After 1 week, the rabbits were sacrificed. The clinical examination as well as the microbiological and histological examinations of organs and middle ear irrigation revealed clear differences between the two groups. P. aeruginosa was detected in every middle ear of the control group and was almost completely eliminated in the study group. Organ examinations revealed the presence of P. aeruginosa in the control group and a prevention of a bacterial spread in the study group. The nanoporous silica layer as antibiotic delivery system showed convincing efficacy in induced pseudomonal otitis media in the rabbit.
    • Elevated expression of VEGFR-3 in lymphatic endothelial cells from lymphangiomas.

      Norgall, Susanne; Papoutsi, Maria; Rössler, Jochen; Schweigerer, Lothar; Wilting, Jörg; Weich, Herbert A; Department Gene Regulation and Differentiation, Helmholtz Centre for Infection Research, Braunschweig, Germany. susannenorgall@gmx.de <susannenorgall@gmx.de> (2007)
      BACKGROUND: Lymphangiomas are neoplasias of childhood. Their etiology is unknown and a causal therapy does not exist. The recent discovery of highly specific markers for lymphatic endothelial cells (LECs) has permitted their isolation and characterization, but expression levels and stability of molecular markers on LECs from healthy and lymphangioma tissues have not been studied yet. We addressed this problem by profiling LECs from normal dermis and two children suffering from lymphangioma, and also compared them with blood endothelial cells (BECs) from umbilical vein, aorta and myometrial microvessels. METHODS: Lymphangioma tissue samples were obtained from two young patients suffering from lymphangioma in the axillary and upper arm region. Initially isolated with anti-CD31 (PECAM-1) antibodies, the cells were separated by FACS sorting and magnetic beads using anti-podoplanin and/or LYVE-1 antibodies. Characterization was performed by FACS analysis, immunofluorescence staining, ELISA and micro-array gene analysis. RESULTS: LECs from foreskin and lymphangioma had an almost identical pattern of lymphendothelial markers such as podoplanin, Prox1, reelin, cMaf and integrin-alpha1 and -alpha9. However, LYVE-1 was down-regulated and VEGFR-2 and R-3 were up-regulated in lymphangiomas. Prox1 was constantly expressed in LECs but not in any of the BECs. CONCLUSION: LECs from different sources express slightly variable molecular markers, but can always be distinguished from BECs by their Prox1 expression. High levels of VEGFR-3 and -2 seem to contribute to the etiology of lymphangiomas.
    • An episomally replicating vector binds to the nuclear matrix protein SAF-A in vivo.

      Jenke, Bok Hee C; Fetzer, Christian P; Stehle, Isa M; Jönsson, Franziska; Fackelmayer, Frank O; Conradt, Harald; Bode, Jürgen; Lipps, Hans J; Institute of Cell Biology, Stockumer Strasse 10, University of Witten/Herdecke, D-58448 Witten. (2002-04)
      pEPI-1, a vector in which a chromosomal scaffold/matrix-attached region (S/MAR) is linked to the simian virus 40 origin of replication, is propagated episomally in CHO cells in the absence of the virally encoded large T-antigen and is stably maintained in the absence of selection pressure. It has been suggested that mitotic stability is provided by a specific interaction of this vector with components of the nuclear matrix. We studied the interactions of pEPI-1 by crosslinking with cis-diamminedichloroplatinum II, after which it is found to copurify with the nuclear matrix. In a south-western analysis, the vector shows exclusive binding to hnRNP-U/SAF-A, a multifunctional scaffold/matrix specific factor. Immunoprecipitation of the crosslinked DNA-protein complex demonstrates that pEPI-1 is bound to this protein in vivo. These data provide the first experimental evidence for the binding of an artificial episome to a nuclear matrix protein in vivo and the basis for understanding the mitotic stability of this novel vector class.