• Bioinformatics tools and database resources for systems genetics analysis in mice--a short review and an evaluation of future needs.

      Durrant, Caroline; Swertz, Morris A; Alberts, Rudi; Arends, Danny; Möller, Steffen; Mott, Richard; Prins, Pjotr; van der Velde, K Joeri; Jansen, Ritsert C; Schughart, Klaus; et al. (2012-03)
      During a meeting of the SYSGENET working group 'Bioinformatics', currently available software tools and databases for systems genetics in mice were reviewed and the needs for future developments discussed. The group evaluated interoperability and performed initial feasibility studies. To aid future compatibility of software and exchange of already developed software modules, a strong recommendation was made by the group to integrate HAPPY and R/qtl analysis toolboxes, GeneNetwork and XGAP database platforms, and TIQS and xQTL processing platforms. R should be used as the principal computer language for QTL data analysis in all platforms and a 'cloud' should be used for software dissemination to the community. Furthermore, the working group recommended that all data models and software source code should be made visible in public repositories to allow a coordinated effort on the use of common data structures and file formats.
    • The bioluminescent Listeria monocytogenes strain Xen32 is defective in flagella expression and highly attenuated in orally infected BALB/cJ mice

      Bergmann, Silke; Rohde, Manfred; Schughart, Klaus; Lengeling, Andreas (2013-07-15)
      Abstract Background In vivo bioluminescence imaging (BLI) is a powerful method for the analysis of host-pathogen interactions in small animal models. The commercially available bioluminescent Listeria monocytogenes strain Xen32 is commonly used to analyse immune functions in knockout mice and pathomechanisms of listeriosis. Findings To analyse and image listerial dissemination after oral infection we have generated a murinised Xen32 strain (Xen32-mur) which expresses a previously described mouse-adapted internalin A. This strain was used alongside the Xen32 wild type strain and the bioluminescent L. monocytogenes strains EGDe-lux and murinised EGDe-mur-lux to characterise bacterial dissemination in orally inoculated BALB/cJ mice. After four days of infection, Xen32 and Xen32-mur infected mice displayed consistently higher rates of bioluminescence compared to EGDe-lux and EGDe-mur-lux infected animals. However, surprisingly both Xen32 strains showed attenuated virulence in orally infected BALB/c mice that correlated with lower bacterial burden in internal organs at day 5 post infection, smaller losses in body weights and increased survival compared to EGDe-lux or EGDe-mur-lux inoculated animals. The Xen32 strain was made bioluminescent by integration of a lux-kan transposon cassette into the listerial flaA locus. We show here that this integration results in Xen32 in a flaA frameshift mutation which makes this strain flagella deficient. Conclusions The bioluminescent L. monocytogenes strain Xen32 is deficient in flagella expression and highly attenuated in orally infected BALB/c mice. As this listerial strain has been used in many BLI studies of murine listeriosis, it is important that the scientific community is aware of its reduced virulence in vivo.
    • The bioluminescent Listeria monocytogenes strain Xen32 is defective in flagella expression and highly attenuated in orally infected BALB/cJ mice.

      Bergmann, Silke; Rohde, Manfred; Schughart, Klaus; Lengeling, Andreas; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2013)
      In vivo bioluminescence imaging (BLI) is a powerful method for the analysis of host-pathogen interactions in small animal models. The commercially available bioluminescent Listeria monocytogenes strain Xen32 is commonly used to analyse immune functions in knockout mice and pathomechanisms of listeriosis.
    • Cellular changes in blood indicate severe respiratory disease during influenza infections in mice.

      Dengler, Leonie; Kühn, Nora; Shin, Dai-Lun; Hatesuer, Bastian; Schughart, Klaus; Wilk, Esther (2014)
      Influenza A infection is a serious threat to human and animal health. Many of the biological mechanisms of the host-pathogen-interactions are still not well understood and reliable biomarkers indicating the course of the disease are missing. The mouse is a valuable model system enabling us to study the local inflammatory host response and the influence on blood parameters under controlled circumstances. Here, we compared the lung and peripheral changes after PR8 (H1N1) influenza A virus infection in C57BL/6J and DBA/2J mice using virus variants of different pathogenicity resulting in non-lethal and lethal disease. We monitored hematological and immunological parameters revealing that the granulocyte to lymphocyte ratio in the blood represents an early indicator of severe disease progression already two days after influenza A infection in mice. These findings might be relevant to optimize early diagnostic options of severe influenza disease and to monitor successful therapeutic treatment in humans.
    • A comparative phenotypic and genomic analysis of C57BL/6J and C57BL/6N mouse strains

      Simon, Michelle M; Greenaway, Simon; White, Jacqueline K; Fuchs, Helmut; Gailus-Durner, Valérie; Wells, Sara; Sorg, Tania; Wong, Kim; Bedu, Elodie; Cartwright, Elizabeth J; et al. (2013-07-31)
      Abstract Background The mouse inbred line C57BL/6J is widely used in mouse genetics and its genome has been incorporated into many genetic reference populations. More recently large initiatives such as the International Knockout Mouse Consortium (IKMC) are using the C57BL/6N mouse strain to generate null alleles for all mouse genes. Hence both strains are now widely used in mouse genetics studies. Here we perform a comprehensive genomic and phenotypic analysis of the two strains to identify differences that may influence their underlying genetic mechanisms. Results We undertake genome sequence comparisons of C57BL/6J and C57BL/6N to identify SNPs, indels and structural variants, with a focus on identifying all coding variants. We annotate 34 SNPs and 2 indels that distinguish C57BL/6J and C57BL/6N coding sequences, as well as 15 structural variants that overlap a gene. In parallel we assess the comparative phenotypes of the two inbred lines utilizing the EMPReSSslim phenotyping pipeline, a broad based assessment encompassing diverse biological systems. We perform additional secondary phenotyping assessments to explore other phenotype domains and to elaborate phenotype differences identified in the primary assessment. We uncover significant phenotypic differences between the two lines, replicated across multiple centers, in a number of physiological, biochemical and behavioral systems. Conclusions Comparison of C57BL/6J and C57BL/6N demonstrates a range of phenotypic differences that have the potential to impact upon penetrance and expressivity of mutational effects in these strains. Moreover, the sequence variants we identify provide a set of candidate genes for the phenotypic differences observed between the two strains.
    • Crystal structure of the conserved domain of the DC lysosomal associated membrane protein: implications for the lysosomal glycocalyx.

      Wilke, Sonja; Krausze, Joern; Büssow, Konrad; Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Inhoffenstr, 7, 38124 Braunschweig, Germany. konrad@buessow.com. (2012)
      ABSTRACT:
    • Data-driven assessment of eQTL mapping methods

      Michaelson, Jacob J; Alberts, Rudi; Schughart, Klaus; Beyer, Andreas (2010-09-17)
      Abstract Background The analysis of expression quantitative trait loci (eQTL) is a potentially powerful way to detect transcriptional regulatory relationships at the genomic scale. However, eQTL data sets often go underexploited because legacy QTL methods are used to map the relationship between the expression trait and genotype. Often these methods are inappropriate for complex traits such as gene expression, particularly in the case of epistasis. Results Here we compare legacy QTL mapping methods with several modern multi-locus methods and evaluate their ability to produce eQTL that agree with independent external data in a systematic way. We found that the modern multi-locus methods (Random Forests, sparse partial least squares, lasso, and elastic net) clearly outperformed the legacy QTL methods (Haley-Knott regression and composite interval mapping) in terms of biological relevance of the mapped eQTL. In particular, we found that our new approach, based on Random Forests, showed superior performance among the multi-locus methods. Conclusions Benchmarks based on the recapitulation of experimental findings provide valuable insight when selecting the appropriate eQTL mapping method. Our battery of tests suggests that Random Forests map eQTL that are more likely to be validated by independent data, when compared to competing multi-locus and legacy eQTL mapping methods.
    • Data-driven assessment of eQTL mapping methods.

      Michaelson, Jacob J; Alberts, Rudi; Schughart, Klaus; Beyer, Andreas; Cellular Networks and Systems Biology, Biotechnology Center - TU Dresden, Dresden, Germany. (2010)
      The analysis of expression quantitative trait loci (eQTL) is a potentially powerful way to detect transcriptional regulatory relationships at the genomic scale. However, eQTL data sets often go underexploited because legacy QTL methods are used to map the relationship between the expression trait and genotype. Often these methods are inappropriate for complex traits such as gene expression, particularly in the case of epistasis.
    • Deletion of Irf3 and Irf7 Genes in Mice Results in Altered Interferon Pathway Activation and Granulocyte-Dominated Inflammatory Responses to Influenza A Infection.

      Hatesuer, Bastian; Hoang, Hang Thi Thu; Riese, Peggy; Trittel, Stephanie; Gerhauser, Ingo; Elbahesh, Husni; Geffers, Robert; Wilk, Esther; Schughart, Klaus; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr.7, 38124 Braunschweig, Germany. (2017)
      The interferon (IFN) pathway plays an essential role in the innate immune response following viral infections and subsequent shaping of adaptive immunity. Infections with influenza A viruses (IAV) activate the IFN pathway after the recognition of pathogen-specific molecular patterns by respective pattern recognition receptors. The IFN regulatory factors IRF3 and IRF7 are key players in the regulation of type I and III IFN genes. In this study, we analyzed the role of IRF3 and IRF7 for the host response to IAV infections in Irf3-/-, Irf7-/-, and Irf3-/-Irf7-/- knockout mice. While the absence of IRF3 had only a moderate impact on IFN expression, deletion of IRF7 completely abolished IFNα production after infection. In contrast, lack of both IRF3 and IRF7 resulted in the absence of both IFNα and IFNβ after IAV infection. In addition, IAV infection of double knockout mice resulted in a strong increase of mortality associated with a massive influx of granulocytes in the lung and reduced activation of the adaptive immune response.
    • Detection of anti-HPV11-L1 antibodies in immune sera from patients suffering from recurrent respiratory papillomatosis using ELISA.

      Durzyńska, Julia; Błazejewska, Paulina; Szydłowski, Jarosław; Goździcka-Józefiak, Anna; Department of Molecular Virology, Faculty of Biology, University of A. Mickiewicz, Poznan, Poznan. juliadur@amu.edu.pl (2010-08)
      Infection with human papillomaviruses (mostly HPV6 and HPV11) may lead to recurrent respiratory papillomatosis (RRP), a chronic disease affecting 2-4/100,000 people. Papillomas have to be removed surgically so patients can breathe normally. Papillomas often grow back and some patients are subjected to a number of operations. In general, asymptomatic HPV-positive people have low levels of antiviral antibodies in their sera, as the human humoral response is weak due to HPV's biology. In patients suffering from RRP who have undergone multiple surgeries, a blood-epithelium barrier breach stimulates the production of anti-HPV antibodies. Our study's aim was to produce HisTag-HPV11-L1 major capsid protein in E. coli cells, and to purify it. We also sought to detect anti-HPV11-L1 antibodies in antisera obtained from RRP patients using ELISA. Clinical samples were collected from 47 patients with RRP (antisera and papillomas), and from 32 controls (sera and oral swabs), from the Wielkopolska region of Poland. Antisera and control sera were used to coat microplates, HisTag-HPV11-L1 antigen was applied, and antibody-antigen complexes were detected by anti-HisTag monoclonal antibody in an ELISA assay. Simultaneously, total cellular DNA was extracted from papillomas and oral squamous cells obtained from controls. All DNA samples were screened for HPV DNA using MY-PCR. All patients were HPV-positive (30% for HPV6 and 70% for HPV11). Statistically significant correlations were found between the amount of anti-HPV11-L1 antibodies in the sera of RRP patients and the number of surgical procedures they underwent. Although HPV virus-like particles are most often used for anti-HPV antibody detection, the ELISA method presented herein is another viable option for use in RRP patients.
    • Distinct gene loci control the host response to influenza H1N1 virus infection in a time-dependent manner.

      Nedelko, Tatiana; Kollmus, Heike; Klawonn, Frank; Spijker, Sabine; Lu, Lu; Heßman, Manuela; Alberts, Rudi; Williams, Robert W; Schughart, Klaus; Department of Infection Genetics, Helmholtz Centre for Infection Research and University of Veterinary Medicine Hannover, 38124, Braunschweig, Germany. (2012)
      There is strong but mostly circumstantial evidence that genetic factors modulate the severity of influenza infection in humans. Using genetically diverse but fully inbred strains of mice it has been shown that host sequence variants have a strong influence on the severity of influenza A disease progression. In particular, C57BL/6J, the most widely used mouse strain in biomedical research, is comparatively resistant. In contrast, DBA/2J is highly susceptible.
    • Dynamic gene network reconstruction from gene expression data in mice after influenza A (H1N1) infection

      Dimitrakopoulou, Konstantina; Tsimpouris, Charalampos; Papadopoulos, George; Pommerenke, Claudia; Wilk, Esther; Sgarbas, Kyriakos N; Schughart, Klaus; Bezerianos, Anastasios (2011-10-21)
      Abstract Background The immune response to viral infection is a temporal process, represented by a dynamic and complex network of gene and protein interactions. Here, we present a reverse engineering strategy aimed at capturing the temporal evolution of the underlying Gene Regulatory Networks (GRN). The proposed approach will be an enabling step towards comprehending the dynamic behavior of gene regulation circuitry and mapping the network structure transitions in response to pathogen stimuli. Results We applied the Time Varying Dynamic Bayesian Network (TV-DBN) method for reconstructing the gene regulatory interactions based on time series gene expression data for the mouse C57BL/6J inbred strain after infection with influenza A H1N1 (PR8) virus. Initially, 3500 differentially expressed genes were clustered with the use of k-means algorithm. Next, the successive in time GRNs were built over the expression profiles of cluster centroids. Finally, the identified GRNs were examined with several topological metrics and available protein-protein and protein-DNA interaction data, transcription factor and KEGG pathway data. Conclusions Our results elucidate the potential of TV-DBN approach in providing valuable insights into the temporal rewiring of the lung transcriptome in response to H1N1 virus.
    • Dynamic gene network reconstruction from gene expression data in mice after influenza A (H1N1) infection.

      Dimitrakopoulou, Konstantina; Tsimpouris, Charalampos; Papadopoulos, George; Pommerenke, Claudia; Wilk, Esther; Sgarbas, Kyriakos N; Schughart, Klaus; Bezerianos, Anastasios; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2011)
      The immune response to viral infection is a temporal process, represented by a dynamic and complex network of gene and protein interactions. Here, we present a reverse engineering strategy aimed at capturing the temporal evolution of the underlying Gene Regulatory Networks (GRN). The proposed approach will be an enabling step towards comprehending the dynamic behavior of gene regulation circuitry and mapping the network structure transitions in response to pathogen stimuli.
    • Eine innovative Mauspopulation als genetisches Modell für den Menschen

      Leist, Sarah; Kollmus, Heike; Pilzner, Carolin; Schughart, Klaus; Infektionsgenetic, Hemholtz Zentrum für Infektionsforschung, Inhoffenstr. 7, 38125Braunschweig (2013-11-21)
    • The endosomal Toll-like receptors 7 and 9 cooperate in detection of MHV68 infection.

      Bussey, Kendra A; Murthy, Sripriya; Reimer, Elisa; Chan, Baca; Hatesuer, Bastian; Schughart, Klaus; Glaunsinger, Britt; Adler, Heiko; Brinkmann, Melanie M; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Amercan Society of Microbiology, 2018-11-14)
      Murine gammaherpesvirus 68 (MHV68) is an amenable small animal model for study of the human pathogens Epstein-Barr virus and Kaposi’s sarcoma-associated herpesvirus. Here, we have characterized the roles of the endosomal TLR escort protein UNC93B, endosomal TLR7, 9, and 13, and cell surface TLR2 in MHV68 detection. We found that the interferon α (IFNα) response of plasmacytoid dendritic cells (pDC) to MHV68 was reduced in Tlr9-/- cells compared to wildtype (WT), but not completely lost. Tlr7-/- pDC responded similarly to WT. However, we found that in Unc93b-/- pDC, as well as in Tlr7/Tlr9-/- double knockout pDC, the IFNα response to MHV68 was completely abolished. Thus, the only pattern recognition receptors contributing to the IFNα response to MHV68 in pDC are TLR7 and TLR9, but the contribution of TLR7 is masked by the presence of TLR9. To address the role of UNC93B and TLR for MHV68 infection in vivo, we infected mice with MHV68. Lytic replication of MHV68 after intravenous infection was enhanced in the lungs, spleen, and liver of UNC93B-deficient mice, in the spleen of TLR9-deficient mice, and in the liver and spleen of Tlr7/Tlr9-/- mice. The absence of TLR2 or TLR13 did not affect lytic viral titers. We then compared reactivation of MHV68 from latently infected WT, Unc93b-/-, Tlr7/Tlr9-/-, Tlr7-/-, and Tlr9-/- splenocytes. We observed enhanced reactivation and latent viral loads, particularly from Tlr7/Tlr9-/- splenocytes, compared to WT. Our data show that UNC93B- dependent TLR7 and TLR9 cooperate in and contribute to detection and control of MHV68 infection.
    • Equivalence of self- and staff-collected nasal swabs for the detection of viral respiratory pathogens.

      Akmatov, Manas K; Gatzemeier, Anja; Schughart, Klaus; Pessler, Frank; Department of Epidemiology, Helmholtz Centre for Infection Research, Braunschweig, Germany. (2012)
      The need for the timely collection of diagnostic biosamples during symptomatic episodes represents a major obstacle to large-scale studies on acute respiratory infection (ARI) epidemiology. This may be circumvented by having the participants collect their own nasal swabs. We compared self- and staff-collected swabs in terms of swabbing quality and detection of viral respiratory pathogens.
    • Exchange of amino acids in the H1-haemagglutinin to H3 residues is required for efficient influenza A virus replication and pathology in Tmprss2 knock-out mice.

      Lambertz, Ruth L O; Pippel, Jan; Gerhauser, Ingo; Kollmus, Heike; Anhlan, Darisuren; Hrincius, Eike R; Krausze, Joern; Kühn, Nora; Schughart, Klaus; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2018-09-01)
      The haemagglutinin (HA) of H1N1 and H3N2 influenza A virus (IAV) subtypes has to be activated by host proteases. Previous studies showed that H1N1 virus cannot replicate efficiently in Tmprss2/ knock-out mice whereas H3N2 viruses are able to replicate to the same levels in Tmprss2/ as in wild type (WT) mice. Here, we investigated the sequence requirements for the HA molecule that allow IAV to replicate efficiently in the absence of TMPRSS2. We showed that replacement of the H3 for the H1-loop sequence (amino acids 320 to 329, at the C-terminus of HA1) was not sufficient for equal levels of virus replication or severe pathology in Tmprss2/ knock-out mice compared to WT mice. However, exchange of a distant amino acid from H1 to H3 sequence (E31D) in addition to the HA-loop substitution resulted in virus replication in Tmprss2/ knockout mice that was comparable to WT mice. The higher virus replication and lung damage was associated with increased epithelial damage and higher mortality. Our results provide further evidence and insights into host proteases as a promising target for therapeutic intervention of IAV infections.
    • Expression QTL mapping in regulatory and helper T cells from the BXD family of strains reveals novel cell-specific genes, gene-gene interactions and candidate genes for auto-immune disease

      Alberts, Rudi; Chen, Hairong; Pommerenke, Claudia; Smit, August B; Spijker, Sabine; Williams, Robert W; Geffers, Robert; Bruder, Dunja; Schughart, Klaus (2011-12-19)
      Abstract Background Regulatory T cells (Tregs) play an essential role in the control of the immune response. Treg cells represent important targets for therapeutic interventions of the immune system. Therefore, it will be very important to understand in more detail which genes are specifically activated in Treg cells versus T helper (Th) cells, and which gene regulatory circuits may be involved in specifying and maintaining Treg cell homeostasis. Results We isolated Treg and Th cells from a genetically diverse family of 31 BXD type recombinant inbred strains and the fully inbred parental strains of this family--C57BL/6J and DBA/2J. Subsequently genome-wide gene expression studies were performed from the isolated Treg and Th cells. A comparative analysis of the transcriptomes of these cell populations allowed us to identify many novel differentially expressed genes. Analysis of cis- and trans-expression Quantitative Trait Loci (eQTLs) highlighted common and unique regulatory mechanisms that are active in the two cell types. Trans-eQTL regions were found for the Treg functional genes Nrp1, Stat3 and Ikzf4. Analyses of the respective QTL intervals suggested several candidate genes that may be involved in regulating these genes in Treg cells. Similarly, possible candidate genes were found which may regulate the expression of F2rl1, Ctla4, Klrb1f. In addition, we identified a focused group of candidate genes that may be important for the maintenance of self-tolerance and the prevention of allergy. Conclusions Variation of expression across the strains allowed us to find many novel gene-interaction networks in both T cell subsets. In addition, these two data sets enabled us to identify many differentially expressed genes and to nominate candidate genes that may have important functions for the maintenance of self-tolerance and the prevention of allergy.
    • Gene expression changes in the host response between resistant and susceptible inbred mouse strains after influenza A infection.

      Alberts, Rudi; Srivastava, Barkha; Wu, Haiya; Viegas, Nuno; Geffers, Robert; Klawonn, Frank; Novoselova, Natalia; do Valle, Tania Zaverucha; Panthier, Jean-Jacques; Schughart, Klaus; et al. (2010-04)
      Inbred mouse strains exhibit differences in susceptibility to influenza A infections. However, the molecular mechanisms underlying these differences are unknown. Therefore, we infected a highly susceptible mouse strain (DBA/2J) and a resistant strain (C57BL/6J) with influenza A H1N1 (PR8) and performed genome-wide expression analysis. We found genes expressed in lung epithelium that were specifically down-regulated in DBA/2J mice, whereas a cluster of genes on chromosome 3 was only down-regulated in C57BL/6J. In both mouse strains, chemokines, cytokines and interferon-response genes were up-regulated, indicating that the main innate immune defense pathways were activated. However, many immune response genes were up-regulated in DBA/2J much stronger than in C57BL/6J, and several immune response genes were exclusively regulated in DBA/2J. Thus, susceptible DBA/2J mice showed a hyper-inflammatory response. This response is similar to infections with highly pathogenic influenza virus and may serve as a paradigm for a hyper-inflammatory host response to influenza A virus.
    • Genetically diverse CC-founder mouse strains replicate the human influenza gene expression signature.

      Elbahesh, Husni; Schughart, Klaus; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2016-05-19)
      Influenza A viruses (IAV) are zoonotic pathogens that pose a major threat to human and animal health. Influenza virus disease severity is influenced by viral virulence factors as well as individual differences in host response. We analyzed gene expression changes in the blood of infected mice using a previously defined set of signature genes that was derived from changes in the blood transcriptome of IAV-infected human volunteers. We found that the human signature was reproduced well in the founder strains of the Collaborative Cross (CC) mice, thus demonstrating the relevance and importance of mouse experimental model systems for studying human influenza disease.