Publications by authors named "Klaus Schughart"

89 Publications

Cell culture-based production and in vivo characterization of purely clonal defective interfering influenza virus particles.

BMC Biol 2021 May 3;19(1):91. Epub 2021 May 3.

Otto-von-Guericke-University Magdeburg, Chair of Bioprocess Engineering, Magdeburg, Germany.

Background: Infections with influenza A virus (IAV) cause high morbidity and mortality in humans. Additional to vaccination, antiviral drugs are a treatment option. Besides FDA-approved drugs such as oseltamivir or zanamivir, virus-derived defective interfering (DI) particles (DIPs) are considered promising new agents. IAV DIPs typically contain a large internal deletion in one of their eight genomic viral RNA (vRNA) segments. Consequently, DIPs miss the genetic information necessary for replication and can usually only propagate by co-infection with infectious standard virus (STV), compensating for their defect. In such a co-infection scenario, DIPs interfere with and suppress STV replication, which constitutes their antiviral potential.

Results: In the present study, we generated a genetically engineered MDCK suspension cell line for production of a purely clonal DIP preparation that has a large deletion in its segment 1 (DI244) and is not contaminated with infectious STV as egg-derived material. First, the impact of the multiplicity of DIP (MODIP) per cell on DI244 yield was investigated in batch cultivations in shake flasks. Here, the highest interfering efficacy was observed for material produced at a MODIP of 1E-2 using an in vitro interference assay. Results of RT-PCR suggested that DI244 material produced was hardly contaminated with other defective particles. Next, the process was successfully transferred to a stirred tank bioreactor (500 mL working volume) with a yield of 6.0E+8 PFU/mL determined in genetically modified adherent MDCK cells. The produced material was purified and concentrated about 40-fold by membrane-based steric exclusion chromatography (SXC). The DI244 yield was 92.3% with a host cell DNA clearance of 97.1% (99.95% with nuclease digestion prior to SXC) and a total protein reduction of 97.2%. Finally, the DIP material was tested in animal experiments in D2(B6).A2G-Mx1 mice. Mice infected with a lethal dose of IAV and treated with DIP material showed a reduced body weight loss and all animals survived.

Conclusion: In summary, experiments not only demonstrated that purely clonal influenza virus DIP preparations can be obtained with high titers from animal cell cultures but confirmed the potential of cell culture-derived DIPs as an antiviral agent.
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http://dx.doi.org/10.1186/s12915-021-01020-5DOI Listing
May 2021

Blood transcriptome analysis of patients with uncomplicated bacterial infection and sepsis.

BMC Res Notes 2021 Feb 27;14(1):76. Epub 2021 Feb 27.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

Objectives: Hospitalized patients who presented within the last 24 h with a bacterial infection were recruited. Participants were assigned into sepsis and uncomplicated infection groups. In addition, healthy volunteers were recruited as controls. RNA was prepared from whole blood, depleted from beta-globin mRNA and sequenced. This dataset represents a highly valuable resource to better understand the biology of sepsis and to identify biomarkers for severe sepsis in humans.

Data Description: The data presented here consists of raw and processed transcriptome data obtained by next generation RNA sequencing from 105 peripheral blood samples from patients with uncomplicated infections, patients who developed sepsis, septic shock patients, and healthy controls. It is provided as raw sequenced reads and as normalized log transformed relative expression levels. This data will allow performing detailed analyses of gene expression changes between uncomplicated infections and sepsis patients, such as identification of differentially expressed genes, co-regulated modules as well as pathway activation studies.
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http://dx.doi.org/10.1186/s13104-021-05488-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913415PMC
February 2021

Highly dampened blood transcriptome response in HIV patients after influenza infection.

Sci Rep 2021 Feb 24;11(1):4465. Epub 2021 Feb 24.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Brunswick, Germany.

Respiratory viral (RV) infections represent a major threat for human health worldwide. Persons with HIV (PWH) have a compromised immune response and are thought to be at higher risk for severe RV disease. However, very little is known about the host immune response to RV infection in PWH. Here, we investigated gene expression changes in the peripheral blood of PWH co-infected with RV. Only very few differentially expressed genes could be detected between PWH with and without RV infection, suggesting that the immune response to RV in PWH is strongly dampened. Our data provides important insights into the host response to RV infections in HIV patients.
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http://dx.doi.org/10.1038/s41598-021-83876-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904929PMC
February 2021

Genetic Dissection of the Regulatory Mechanisms of in the Infected Mouse Lung.

Front Immunol 2020 8;11:607314. Epub 2021 Jan 8.

Department of Genetics, Genomics, and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States.

Acute lung injury (ALI) is an important cause of morbidity and mortality after viral infections, including influenza A virus H1N1, SARS-CoV, MERS-CoV, and SARS-CoV-2. The angiotensin I converting enzyme 2 (ACE2) is a key host membrane-bound protein that modulates ALI induced by viral infection, pulmonary acid aspiration, and sepsis. However, the contributions of sequence variants to individual differences in disease risk and severity after viral infection are not understood. In this study, we quantified H1N1 influenza-infected lung transcriptomes across a family of 41 BXD recombinant inbred strains of mice and both parents-C57BL/6J and DBA/2J. In response to infection mRNA levels decreased significantly for both parental strains and the expression levels was associated with disease severity (body weight loss) and viral load (expression levels of viral NA segment) across the BXD family members. Pulmonary RNA-seq for 43 lines was analyzed using weighted gene co-expression network analysis (WGCNA) and Bayesian network approaches. not only participated in virus-induced ALI by interacting with TNF, MAPK, and NOTCH signaling pathways, but was also linked with high confidence to gene products that have important functions in the pulmonary epithelium, including , , and . Comparable sets of transcripts were also highlighted in parallel studies of human SARS-CoV-infected primary human airway epithelial cells. Using conventional mapping methods, we determined that weight loss at two and three days after viral infection maps to chromosome X-the location of . This finding motivated the hierarchical Bayesian network analysis, which defined molecular endophenotypes of lung infection linked to expression and to a key disease outcome. Core members of this Bayesian network include , , , , , , , and . Collectively, these findings define a causally-rooted modulatory network relevant to host response to viral infection and identify potential therapeutic targets for virus-induced respiratory diseases, including those caused by influenza and coronaviruses.
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http://dx.doi.org/10.3389/fimmu.2020.607314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7819859PMC
February 2021

Prospective validation study of prognostic biomarkers to predict adverse outcomes in patients with COVID-19: a study protocol.

BMJ Open 2021 01 6;11(1):e044497. Epub 2021 Jan 6.

Division of Primary Care, University of Nottingham, Nottingham, UK.

Introduction: Accurate triage is an important first step to effectively manage the clinical treatment of severe cases in a pandemic outbreak. In the current COVID-19 global pandemic, there is a lack of reliable clinical tools to assist clinicians to perform accurate triage. Host response biomarkers have recently shown promise in risk stratification of disease progression; however, the role of these biomarkers in predicting disease progression in patients with COVID-19 is unknown. Here, we present a protocol outlining a prospective validation study to evaluate the biomarkers' performance in predicting clinical outcomes of patients with COVID-19.

Methods And Analysis: This prospective validation study assesses patients infected with COVID-19, in whom blood samples are prospectively collected. Recruited patients include a range of infection severity from asymptomatic to critically ill patients, recruited from the community, outpatient clinics, emergency departments and hospitals. Study samples consist of peripheral blood samples collected into RNA-preserving (PAXgene/Tempus) tubes on patient presentation or immediately on study enrolment. Real-time PCR (RT-PCR) will be performed on total RNA extracted from collected blood samples using primers specific to host response gene expression biomarkers that have been previously identified in studies of respiratory viral infections. The RT-PCR data will be analysed to assess the diagnostic performance of individual biomarkers in predicting COVID-19-related outcomes, such as viral pneumonia, acute respiratory distress syndrome or bacterial pneumonia. Biomarker performance will be evaluated using sensitivity, specificity, positive and negative predictive values, likelihood ratios and area under the receiver operating characteristic curve.

Ethics And Dissemination: This research protocol aims to study the host response gene expression biomarkers in severe respiratory viral infections with a pandemic potential (COVID-19). It has been approved by the local ethics committee with approval number 2020/ETH00886. The results of this project will be disseminated in international peer-reviewed scientific journals.
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http://dx.doi.org/10.1136/bmjopen-2020-044497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789210PMC
January 2021

OP7, a novel influenza A virus defective interfering particle: production, purification, and animal experiments demonstrating antiviral potential.

Appl Microbiol Biotechnol 2021 Jan 4;105(1):129-146. Epub 2020 Dec 4.

Bioprocess Engineering, Otto von Guericke University Magdeburg, Magdeburg, Germany.

The novel influenza A virus (IAV) defective interfering particle "OP7" inhibits IAV replication in a co-infection and was previously suggested as a promising antiviral agent. Here, we report a batch-mode cell culture-based production process for OP7. In the present study, a seed virus containing standard virus (STV) and OP7 was used. The yield of OP7 strongly depended on the production multiplicity of infection. To inactivate infectious STV in the OP7 material, which may cause harm in a potential application, UV irradiation was used. The efficacy of OP7 in this material was preserved, as shown by an in vitro interference assay. Next, steric exclusion chromatography was used to purify and to concentrate (~ 13-fold) the UV-treated material. Finally, administration of produced OP7 material in mice did not show any toxic effects. Furthermore, all mice infected with a lethal dose of IAV survived the infection upon OP7 co-treatment. Thus, the feasibility of a production workflow for OP7 and its potential for antiviral treatment was demonstrated. KEY POINTS: • OP7 efficacy strongly depended on the multiplicity of infection used for production • Purification by steric exclusion chromatography increased OP7 efficacy • OP7-treated mice were protected against a lethal infection with IAV.
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http://dx.doi.org/10.1007/s00253-020-11029-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7778630PMC
January 2021

Orchestrates Gene Regulatory Variation in Mouse Ventral Midbrain During Aging.

Front Genet 2020 23;11:566734. Epub 2020 Sep 23.

Department of Life Sciences and Medicine, University of Luxembourg, Belvaux, Luxembourg.

Dopaminergic neurons in the midbrain are of particular interest due to their role in diseases such as Parkinson's disease and schizophrenia. Genetic variation between individuals can affect the integrity and function of dopaminergic neurons but the DNA variants and molecular cascades modulating dopaminergic neurons and other cells types of ventral midbrain remain poorly defined. Three genetically diverse inbred mouse strains - C57BL/6J, A/J, and DBA/2J - differ significantly in their genomes (∼7 million variants), motor and cognitive behavior, and susceptibility to neurotoxins. To further dissect the underlying molecular networks responsible for these variable phenotypes, we generated RNA-seq and ChIP-seq data from ventral midbrains of the 3 mouse strains. We defined 1000-1200 transcripts that are differentially expressed among them. These widespread differences may be due to altered activity or expression of upstream transcription factors. Interestingly, transcription factors were significantly underrepresented among the differentially expressed genes, and only one transcription factor, , showed significant differences between all three strains. The changes in expression were accompanied by consistent alterations in histone H3 lysine 4 trimethylation at transcription start site. The ventral midbrain transcriptome of 3-month-old C57BL/6J congenic mutants was only modestly altered, but shifted toward that of A/J and DBA/2J in 9-month-old mice. Principle component analysis (PCA) identified the genes underlying the transcriptome shift and deconvolution of these bulk RNA-seq changes using midbrain single cell RNA-seq data suggested that the changes were occurring in several different cell types, including neurons, oligodendrocytes, and astrocytes. Taken together, our results show that contributes to gene regulatory variation between mouse strains and influences mouse midbrain transcriptome during aging.
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http://dx.doi.org/10.3389/fgene.2020.566734DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538689PMC
September 2020

Complex Genetic Architecture Underlies Regulation of Influenza-A-Virus-Specific Antibody Responses in the Collaborative Cross.

Cell Rep 2020 04;31(4):107587

Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA. Electronic address:

Host genetic factors play a fundamental role in regulating humoral immunity to viral infection, including influenza A virus (IAV). Here, we utilize the Collaborative Cross (CC), a mouse genetic reference population, to study genetic regulation of variation in antibody response following IAV infection. CC mice show significant heritable variation in the magnitude, kinetics, and composition of IAV-specific antibody response. We map 23 genetic loci associated with this variation. Analysis of a subset of these loci finds that they broadly affect the antibody response to IAV as well as other viruses. Candidate genes are identified based on predicted variant consequences and haplotype-specific expression patterns, and several show overlap with genes identified in human mapping studies. These findings demonstrate that the host antibody response to IAV infection is under complex genetic control and highlight the utility of the CC in modeling and identifying genetic factors with translational relevance to human health and disease.
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http://dx.doi.org/10.1016/j.celrep.2020.107587DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7195006PMC
April 2020

H2 influenza A virus is not pathogenic in Tmprss2 knock-out mice.

Virol J 2020 04 22;17(1):56. Epub 2020 Apr 22.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

The host cell protease TMPRSS2 cleaves the influenza A virus (IAV) hemagglutinin (HA). Several reports have described resistance of Tmprss2 knock-out (KO) mice to IAV infection but IAV of the H2 subtype have not been examined yet. Here, we demonstrate that TMPRSS2 is able to cleave H2-HA in cell culture and that Tmprss2 mice are resistant to infection with a re-assorted PR8_HA(H2) virus. Infection of KO mice did not cause major body weight loss or death. Furthermore, no significant increase in lung weights and no virus replication were observed in Tmprss2 mice. Finally, only minor tissue damage and infiltration of immune cells were detected and no virus-positive cells were found in histological sections of Tmprss2 mice. In summary, our studies indicate that TMPRSS2 is required for H2 IAV spread and pathogenesis in mice. These findings extend previous results pointing towards a central role of TMPRSS2 in IAV infection and validate host proteases as a potential target for antiviral therapy.
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http://dx.doi.org/10.1186/s12985-020-01323-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178614PMC
April 2020

Transcriptome profiling and protease inhibition experiments identify proteases that activate H3N2 influenza A and influenza B viruses in murine airways.

J Biol Chem 2020 08 17;295(33):11388-11407. Epub 2020 Apr 17.

Institute of Virology, Philipps-University, 35043 Marburg, Germany

Cleavage of influenza virus hemagglutinin (HA) by host proteases is essential for virus infectivity. HA of most influenza A and B (IAV/IBV) viruses is cleaved at a monobasic motif by trypsin-like proteases. Previous studies have reported that transmembrane serine protease 2 (TMPRSS2) is essential for activation of H7N9 and H1N1pdm IAV in mice but that H3N2 IAV and IBV activation is independent of TMPRSS2 and carried out by as-yet-undetermined protease(s). Here, to identify additional H3 IAV- and IBV-activating proteases, we used RNA-Seq to investigate the protease repertoire of murine lower airway tissues, primary type II alveolar epithelial cells (AECIIs), and the mouse lung cell line MLE-15. Among 13 candidates identified, TMPRSS4, TMPRSS13, hepsin, and prostasin activated H3 and IBV HA IBV activation and replication was reduced in AECIIs from -deficient mice compared with WT or Tmprss2-deficient mice, indicating that murine TMPRSS4 is involved in IBV activation. Multicycle replication of H3N2 IAV and IBV in AECIIs of -deficient mice varied in sensitivity to protease inhibitors, indicating that different, but overlapping, sets of murine proteases facilitate H3 and IBV HA cleavages. Interestingly, human hepsin and prostasin orthologs did not activate H3, but they did activate IBV HA Our results indicate that TMPRSS4 is an IBV-activating protease in murine AECIIs and suggest that TMPRSS13, hepsin, and prostasin cleave H3 and IBV HA in mice. They further show that hepsin and prostasin orthologs might contribute to the differences observed in TMPRSS2-independent activation of H3 in murine and human airways.
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http://dx.doi.org/10.1074/jbc.RA120.012635DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7450141PMC
August 2020

Pathway mapping of leukocyte transcriptome in influenza patients reveals distinct pathogenic mechanisms associated with progression to severe infection.

BMC Med Genomics 2020 02 17;13(1):28. Epub 2020 Feb 17.

Department of Intensive Care Medicine, Nepean Hospital, Sydney, Australia.

Background: Influenza infections produce a spectrum of disease severity, ranging from a mild respiratory illness to respiratory failure and death. The host-response pathways associated with the progression to severe influenza disease are not well understood.

Methods: To gain insight into the disease mechanisms associated with progression to severe infection, we analyzed the leukocyte transcriptome in severe and moderate influenza patients and healthy control subjects. Pathway analysis on differentially expressed genes was performed using a topology-based pathway analysis tool that takes into account the interaction between multiple cellular pathways. The pathway profiles between moderate and severe influenza were then compared to delineate the biological mechanisms underpinning the progression from moderate to severe influenza.

Results: 107 patients (44 severe and 63 moderate influenza patients) and 52 healthy control subjects were included in the study. Severe influenza was associated with upregulation in several neutrophil-related pathways, including pathways involved in neutrophil differentiation, migration, degranulation and neutrophil extracellular trap (NET) formation. The degree of upregulation in neutrophil-related pathways were significantly higher in severely infected patients compared to moderately infected patients. Severe influenza was also associated with downregulation in immune response pathways, including pathways involved in antigen presentation such as CD4+ T-cell co-stimulation, CD8+ T cell and Natural Killer (NK) cells effector functions. Apoptosis pathways were also downregulated in severe influenza patients compare to moderate and healthy controls.

Conclusions: These findings showed that there are changes in gene expression profile that may highlight distinct pathogenic mechanisms associated with progression from moderate to severe influenza infection.
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http://dx.doi.org/10.1186/s12920-020-0672-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7027223PMC
February 2020

A comprehensive and comparative phenotypic analysis of the collaborative founder strains identifies new and known phenotypes.

Mamm Genome 2020 02 14;31(1-2):30-48. Epub 2020 Feb 14.

Department of Neurology, Friedrich-Baur-Institute, Klinikum Der Ludwig-Maximilians-Universität München, Ziemssenstr. 1a, 80336, Munich, Germany.

The collaborative cross (CC) is a large panel of mouse-inbred lines derived from eight founder strains (NOD/ShiLtJ, NZO/HILtJ, A/J, C57BL/6J, 129S1/SvImJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ). Here, we performed a comprehensive and comparative phenotyping screening to identify phenotypic differences and similarities between the eight founder strains. In total, more than 300 parameters including allergy, behavior, cardiovascular, clinical blood chemistry, dysmorphology, bone and cartilage, energy metabolism, eye and vision, immunology, lung function, neurology, nociception, and pathology were analyzed; in most traits from sixteen females and sixteen males. We identified over 270 parameters that were significantly different between strains. This study highlights the value of the founder and CC strains for phenotype-genotype associations of many genetic traits that are highly relevant to human diseases. All data described here are publicly available from the mouse phenome database for analyses and downloads.
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http://dx.doi.org/10.1007/s00335-020-09827-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060152PMC
February 2020

Antiviral potential of human IFN-α subtypes against influenza A H3N2 infection in human lung explants reveals subtype-specific activities.

Emerg Microbes Infect 2019 ;8(1):1763-1776

Institute of Virology Muenster, Westfaelische Wilhelms-University, Muenster, Germany.

Influenza is an acute respiratory infection causing high morbidity and mortality in annual outbreaks worldwide. Antiviral drugs are limited and pose the risk of resistance development, calling for new treatment options. IFN-α subtypes are immune-stimulatory cytokines with strong antiviral activities against IAV and However, the clinical use of IFN-α2, the only licensed subtype of this multi-gene family, could not prevent or limit IAV infections in humans. However, the other subtypes were not investigated.Therefore, this study evaluated the induction and antiviral potential of all human IFN-α subtypes during H3N2 IAV infection in human lung explants. We found that subtypes with weak antiviral activities were preferentially induced during IAV infection in human lungs. Intriguingly, non-induced subtypes α16, α5 and α4 suppressed viral replication up to 230-fold more efficiently than α2. Furthermore, our results demonstrate that subtypes with stronger antiviral activities induce higher expression of IAV-specific restriction factors and that MxA expression is a determinant of the subtype-specific antiviral activity towards H3N2 IAV. These results corroborate that IFN-α subtypes exhibit differential antiviral activities and emphasize that subtypes α16, α5 and α4 should be further investigated for the prevention and treatment of severe infections with seasonal H3N2 IAV.
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http://dx.doi.org/10.1080/22221751.2019.1698271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913622PMC
April 2020

Multiplex profiling of inflammation-related bioactive lipid mediators in Toxocara canis- and Toxocara cati-induced neurotoxocarosis.

PLoS Negl Trop Dis 2019 09 26;13(9):e0007706. Epub 2019 Sep 26.

Institute for Parasitology, Centre for Infection Medicine, University of Veterinary Medicine Hannover, Hanover, Germany.

Background: Somatic migration of Toxocara canis- and T. cati-larvae in humans may cause neurotoxocarosis (NT) when larvae accumulate and persist in the central nervous system (CNS). Host- or parasite-induced immunoregulatory processes contribute to the pathogenesis; however, detailed data on involvement of bioactive lipid mediators, e.g. oxylipins or eico-/docosanoids, which are involved in the complex molecular signalling network during infection and inflammation, are lacking.

Methodology/principal Findings: To elucidate if T. canis- and T. cati-induced NT affects the homeostasis of oxylipins during the course of infection, a comprehensive lipidomic profiling in brains (cerebra and cerebella) of experimentally infected C57BL/6J mice was conducted at six different time points post infection (pi) by liquid-chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS). Only minor changes were detected regarding pro-inflammatory prostaglandins (cyclooxygenase pathway). In contrast, a significant increase of metabolites resulting from lipoxygenase pathways was observed for both infection groups and brain regions, implicating a predominantly anti-inflammatory driven immune response. This observation was supported by a significantly increased 13-hydroxyoctadecadienoic acid (HODE)/9-HODE ratio during the subacute phase of infection, indicating an anti-inflammatory response to neuroinfection. Except for the specialised pro-resolving mediator (SPM) neuroprotectin D1 (NPD1), which was detected in mice infected with both pathogens during the subacute phase of infection, no other SPMs were detected.

Conclusions/significance: The obtained results demonstrate the influence of Toxocara spp. on oxylipins as part of the immune response of the paratenic hosts. Furthermore, this study shows differences in the alteration of the oxylipin composition between T. canis- and T. cati-brain infection. Results contribute to a further understanding of the largely unknown pathogenesis and mechanisms of host-parasite interactions during NT.
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http://dx.doi.org/10.1371/journal.pntd.0007706DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6762062PMC
September 2019

Neutrophils-related host factors associated with severe disease and fatality in patients with influenza infection.

Nat Commun 2019 07 31;10(1):3422. Epub 2019 Jul 31.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

Severe influenza infection has no effective treatment available. One of the key barriers to developing host-directed therapy is a lack of reliable prognostic factors needed to guide such therapy. Here, we use a network analysis approach to identify host factors associated with severe influenza and fatal outcome. In influenza patients with moderate-to-severe diseases, we uncover a complex landscape of immunological pathways, with the main changes occurring in pathways related to circulating neutrophils. Patients with severe disease display excessive neutrophil extracellular traps formation, neutrophil-inflammation and delayed apoptosis, all of which have been associated with fatal outcome in animal models. Excessive neutrophil activation correlates with worsening oxygenation impairment and predicted fatal outcome (AUROC 0.817-0.898). These findings provide new evidence that neutrophil-dominated host response is associated with poor outcomes. Measuring neutrophil-related changes may improve risk stratification and patient selection, a critical first step in developing host-directed immune therapy.
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http://dx.doi.org/10.1038/s41467-019-11249-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668409PMC
July 2019

Tmprss2 knock-out mice are resistant to H10 influenza A virus pathogenesis.

J Gen Virol 2019 07 17;100(7):1073-1078. Epub 2019 May 17.

1 Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

The surface protein haemagglutinin (HA) of influenza A viruses (IAV) needs to be cleaved by a host protease to become functional. Here, we investigated if IAV of the H10 subtype also requires TMPRSS2 for replication and pathogenesis in mice. We first showed in cell culture that TMPRSS2 is able to cleave H10-HA. When Tmprss2 deficient mice were infected with a re-assorted virus H10-HA, they did not lose body weight and no viral replication was observed in contrast to wild-type mice. Histopathological analysis showed that inflammatory lesions in the lung of Tmprss2 mice were reduced compared to wild-type mice. In addition, no viral antigen was detected in the lungs of Tmprss2 mice and no evidence for HA cleavage was observed. We conclude from these studies that TMPRSS2 activity is also essential for in vivo replication and pathogenesis of H10 IAV.
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http://dx.doi.org/10.1099/jgv.0.001274DOI Listing
July 2019

Endosomal Toll-Like Receptors 7 and 9 Cooperate in Detection of Murine Gammaherpesvirus 68 Infection.

J Virol 2019 02 17;93(3). Epub 2019 Jan 17.

Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany

Murine gammaherpesvirus 68 (MHV68) is a small-animal model suitable for study of the human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. Here, we have characterized the roles of the endosomal Toll-like receptor (TLR) escort protein UNC93B, endosomal TLR7, -9, and -13, and cell surface TLR2 in MHV68 detection. We found that the alpha interferon (IFN-α) response of plasmacytoid dendritic cells (pDC) to MHV68 was reduced in cells compared to levels in wild type (WT) cells but not completely lost. pDC responded similarly to WT. However, we found that in pDC, as well as in double-knockout pDC, the IFN-α response to MHV68 was completely abolished. Thus, the only pattern recognition receptors contributing to the IFN-α 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 , 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 mice. The absence of TLR2 or TLR13 did not affect lytic viral titers. We then compared reactivation of MHV68 from latently infected WT, , , , and splenocytes. We observed enhanced reactivation and latent viral loads, particularly from splenocytes compared to levels in the WT. Our data show that UNC93B-dependent TLR7 and TLR9 cooperate in and contribute to detection and control of MHV68 infection. The two human gammaherpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), can cause aggressive forms of cancer. These herpesviruses are strictly host specific, and therefore the homolog murine gammaherpesvirus 68 (MHV68) is a widely used model to obtain insights into the interaction between these two gammaherpesviruses and their host. Like EBV and KSHV, MHV68 establishes lifelong latency in B cells. The innate immune system serves as one of the first lines of host defense, with pattern recognition receptors such as the Toll-like receptors playing a crucial role in mounting a potent antiviral immune response to various pathogens. Here, we shed light on a yet unanticipated role of Toll-like receptor 7 in the recognition of MHV68 in a subset of immune cells called plasmacytoid dendritic cells, as well as on the control of this virus in its host.
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http://dx.doi.org/10.1128/JVI.01173-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340039PMC
February 2019

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.

J Gen Virol 2018 09 6;99(9):1187-1198. Epub 2018 Aug 6.

1​Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

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 knock-out 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.
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http://dx.doi.org/10.1099/jgv.0.001128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6230768PMC
September 2018

TMPRSS11A activates the influenza A virus hemagglutinin and the MERS coronavirus spike protein and is insensitive against blockade by HAI-1.

J Biol Chem 2018 09 5;293(36):13863-13873. Epub 2018 Jul 5.

From the Infection Biology Unit, German Primate Center-Leibniz Institute for Primate Research, 37077 Göttingen, Germany,

The influenza virus hemagglutinin (HA) facilitates viral entry into target cells. Cleavage of HA by host cell proteases is essential for viral infectivity, and the responsible enzymes are potential targets for antiviral intervention. The type II transmembrane serine protease (TTSP) TMPRSS2 has been identified as an HA activator in cell culture and in the infected host. However, it is less clear whether TMPRSS2-related enzymes can also activate HA for spread in target cells. Moreover, the activity of cellular serine protease inhibitors against HA-activating TTSPs is poorly understood. Here, we show that TMPRSS11A, another member of the TTSP family, cleaves and activates the influenza A virus (FLUAV) HA and the Middle East respiratory syndrome coronavirus spike protein (MERS-S). Moreover, we demonstrate that TMPRSS11A is expressed in murine tracheal epithelium, which is a target of FLUAV infection, and in human trachea, suggesting that the protease could support FLUAV spread in patients. Finally, we show that HA activation by the TMPRSS11A-related enzymes human airway tryptase and DESC1, but not TMPRSS11A itself, is blocked by the cellular serine protease inhibitor hepatocyte growth factor activator inhibitor type-1 (HAI-1). Our results suggest that TMPRSS11A could promote FLUAV spread in target cells and that HA-activating TTSPs exhibit differential sensitivity to blockade by cellular serine protease inhibitors.
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http://dx.doi.org/10.1074/jbc.RA118.001273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6130959PMC
September 2018

Of mice and men: the host response to influenza virus infection.

Mamm Genome 2018 08 15;29(7-8):446-470. Epub 2018 Jun 15.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Brunswick, Germany.

Influenza virus (IV) infections represent a very serious public health problem. At present, no established biomarkers exist to support diagnosis for respiratory viral infections and more importantly for severe IV disease. Studies in animal models are extremely important to understand the biological, genetic, and environmental factors that contribute to severe IV disease and to validate biomarker candidates from human studies. However, mouse human cross-species comparisons are often compromised by the fact that animal studies concentrate on the infected lungs, whereas in humans almost all studies use peripheral blood from patients. In addition, human studies do not consider genetic background as variable although human populations are genetically very diverse. Therefore, in this study, we performed a cross-species gene expression study of the peripheral blood from human patients and from the highly genetically diverse Collaborative Cross (CC) mouse population after IV infection. Our results demonstrate that changes of gene expression in individual genes are highly similar in mice and humans. The top-regulated genes in humans were also differentially regulated in mice. We conclude that the mouse is a highly valuable in vivo model system to validate and to discover gene candidates which can be used as biomarkers in humans. Furthermore, mouse studies allow confirmation of findings in humans in a well-controlled experimental system adding enormous value to the understanding of expression and function of human candidate genes.
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http://dx.doi.org/10.1007/s00335-018-9750-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132725PMC
August 2018

Long-Term Neuroinflammation Induced by Influenza A Virus Infection and the Impact on Hippocampal Neuron Morphology and Function.

J Neurosci 2018 03 27;38(12):3060-3080. Epub 2018 Feb 27.

Department of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany,

Acute influenza infection has been reported to be associated with neurological symptoms. However, the long-term consequences of an infection with neurotropic and non-neurotropic influenza A virus (IAV) variants for the CNS remain elusive. We can show that spine loss in the hippocampus after infection with neurotropic H7N7 (rSC35M) and non-neurotropic H3N2 (maHK68) in female C57BL/6 mice persists well beyond the acute phase of the disease. Although spine number was significantly reduced at 30 d postinfection (dpi) with H7N7 or H3N2, full recovery could only be observed much later at 120 dpi. Infection with H1N1 virus, which was shown previously to affect spine number and hippocampus-dependent learning acutely, had no significant long-term effects. Spine loss was associated with an increase in the number of activated microglia, reduced long-term potentiation in the hippocampus, and impairment in spatial memory formation, indicating that IAV-associated inflammation induced functional and structural alterations in hippocampal networks. Transcriptome analyses revealed regulation of many inflammatory and neuron- and glia-specific genes in H3N2- and H7N7-infected mice at day 18 and in H7N7-infected mice at day 30 pi that related to the structural and functional alterations. Our data provide evidence that neuroinflammation induced by neurotropic H7N7 and infection of the lung with a non-neurotropic H3N2 IAV result in long-term impairments in the CNS. IAV infection in humans may therefore not only lead to short-term responses in infected organs, but may also trigger neuroinflammation and associated chronic alterations in the CNS. In the acute phase of influenza infection, neuroinflammation can lead to alterations in hippocampal neuronal morphology and cognitive deficits. The results of this study now also provide evidence that neuroinflammation induced by influenza A virus (IAV) infection can induce longer-lasting, virus-specific alterations in neuronal connectivity that are still detectable 1 month after infection and are associated with impairments in spatial memory formation. IAV infection in humans may therefore not only lead to short-term responses in infected organs, but may also trigger neuroinflammation and associated chronic alterations in the CNS.
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http://dx.doi.org/10.1523/JNEUROSCI.1740-17.2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6596076PMC
March 2018

Increased virulence of a PB2/HA mutant of an avian H9N2 influenza strain after three passages in porcine differentiated airway epithelial cells.

Vet Microbiol 2017 Nov 16;211:129-134. Epub 2017 Oct 16.

Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany. Electronic address:

We analyzed the adaptation of influenza viruses to growth in differentiated airway epithelial cells of a new host by passaging an avian H9N2 virus three times in porcine precision-cut lung slices (PCLS). Sequence analysis revealed four mutations: one each in the PB2 and NS1 proteins, and two in the HA protein. In this study, we characterized the PB2 mutation G685R by generating recombinant H9N2 viruses containing the PB2 single mutation alone or in combination with one of the HA mutations (A190V or T212I). When analyzed in porcine cells - a tracheal cell line (NPTr) or PCLS - the PB2-685 mutant did not provide a growth advantage and had no effect on the ciliary activity which is a virulence marker of swine influenza viruses. Pathogenicity for mice was also not increased by the single PB2 mutation. However, both double mutants (HA-190+PB2-685 and HA-212+PB2-685) showed significantly increased virulence in mice. Therefore, the mutations in the HA and PB2 proteins may confer early adaptation of an avian H9N2 virus to a mammalian host. In conclusion, we expect that a broader ensemble of mutations will be required to render an H9N2 virus virulent for pigs.
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http://dx.doi.org/10.1016/j.vetmic.2017.10.015DOI Listing
November 2017

Absence of regulator of G-protein signaling 4 does not protect against dopamine neuron dysfunction and injury in the mouse 6-hydroxydopamine lesion model of Parkinson's disease.

Neurobiol Aging 2017 10 19;58:30-33. Epub 2017 Jun 19.

Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg. Electronic address:

Regulator of G-protein signaling 4 (RGS4), a member of the RGS family of proteins that inactivate G-proteins, has gained interest as a potential drug target for neurological disorders, such as epilepsy and Parkinson's disease (PD). In the case of PD, the main current options for alleviating motor symptoms are dopamine replacement therapies, which have limitations because of side effects and reduced effectiveness over the long term. Research on new nondopaminergic PD drug targets has indicated that inhibition of RGS4 could be an effective adjuvant treatment option. The effectiveness of RGS4 inhibition for an array of PD-linked functional and structural neuroprotection end points has not yet been demonstrated. Here, we use the 6-hydroxydopamine (6-OHDA) lesioning model of the nigrostriatal pathway in mice to address this question. We observe, using a battery of behavioral and pathological measures, that mice deficient for RGS4 are not protected from 6-OHDA-induced injury and show enhanced susceptibility in some measures of motor function. Our results suggest that inhibition of RGS4 as a nondopaminergic target for PD should be approached with caution.
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http://dx.doi.org/10.1016/j.neurobiolaging.2017.06.008DOI Listing
October 2017

A novel immune biomarker discriminates between influenza and bacteria in patients with suspected respiratory infection.

Eur Respir J 2017 06 15;49(6). Epub 2017 Jun 15.

Dept of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

Host response biomarkers can accurately distinguish between influenza and bacterial infection. However, published biomarkers require the measurement of many genes, thereby making it difficult to implement them in clinical practice. This study aims to identify a single-gene biomarker with a high diagnostic accuracy equivalent to multi-gene biomarkers.In this study, we combined an integrated genomic analysis of 1071 individuals with experiments using well-established infection models.We identified a single-gene biomarker, , which had a high prediction accuracy (91%) equivalent to that obtained by multi-gene biomarkers. studies showed that was upregulated by TLR7 in plasmacytoid dendritic cells, antigen-presenting cells that responded to influenza virus rather than bacteria. studies confirmed that was expressed in influenza patients but not in bacterial infection, as demonstrated in multiple patient cohorts (n=521). In a large prospective study (n=439) of patients presented with undifferentiated respiratory illness (aetiologies included viral, bacterial and non-infectious conditions), displayed 88% diagnostic accuracy (AUC) and 90% specificity in discriminating between influenza and bacterial infections. represents a significant step forward in overcoming a translational barrier in applying genomic assay in clinical setting; its implementation may improve the diagnosis and management of respiratory infection.
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http://dx.doi.org/10.1183/13993003.02098-2016DOI Listing
June 2017

Host Genetic Background Strongly Affects Pulmonary microRNA Expression before and during Influenza A Virus Infection.

Front Immunol 2017 21;8:246. Epub 2017 Mar 21.

Institute for Experimental Infection Research, TWINCORE Center for Experimental and Clinical Infection Research, Hannover, Germany; Helmholtz Centre for Infection Research, Braunschweig, Germany; Centre for Individualised Infection Medicine, Hannover, Germany.

Background: Expression of host microRNAs (miRNAs) changes markedly during influenza A virus (IAV) infection of natural and adaptive hosts, but their role in genetically determined host susceptibility to IAV infection has not been explored. We, therefore, compared pulmonary miRNA expression during IAV infection in two inbred mouse strains with differential susceptibility to IAV infection.

Results: miRNA expression profiles were determined in lungs of the more susceptible strain DBA/2J and the less susceptible strain C57BL/6J within 120 h post infection (hpi) with IAV (H1N1) PR8. Even the miRNomes of uninfected lungs differed substantially between the two strains. After a period of relative quiescence, major miRNome reprogramming was detected in both strains by 48 hpi and increased through 120 hpi. Distinct groups of miRNAs regulated by IAV infection could be defined: (1) miRNAs ( = 39) whose expression correlated with hemagglutinin (HA) mRNA expression and represented the general response to IAV infection independent of host genetic background; (2) miRNAs ( = 20) whose expression correlated with HA mRNA expression but differed between the two strains; and (3) remarkably, miR-147-3p, miR-208b-3p, miR-3096a-5p, miR-3069b-3p, and the miR-467 family, whose abundance even in uninfected lungs differentiated nearly perfectly (area under the ROC curve > 0.99) between the two strains throughout the time course, suggesting a particularly strong association with the differential susceptibility of the two mouse strains. Expression of subsets of miRNAs correlated significantly with peripheral blood granulocyte and monocyte numbers, particularly in DBA/2J mice; miR-223-3p, miR-142-3p, and miR-20b-5p correlated most positively with these cell types in both mouse strains. Higher abundance of antiapoptotic (e.g., miR-467 family) and lower abundance of proapoptotic miRNAs (e.g., miR-34 family) and those regulating the PI3K-Akt pathway (e.g., miR-31-5p) were associated with the more susceptible DBA/2J strain.

Conclusion: Substantial differences in pulmonary miRNA expression between the two differentially susceptible mouse strains were evident even before infection, but evolved further throughout infection and could in part be attributed to differences in peripheral blood leukocyte populations. Thus, pulmonary miRNA expression both before and during IAV infection is in part determined genetically and contributes to susceptibility to IAV infection in this murine host, and likely in humans.
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http://dx.doi.org/10.3389/fimmu.2017.00246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359533PMC
March 2017

QTL Mapping and Identification of Candidate Genes in DO Mice: A Use Case Model Derived from a Benzene Toxicity Experiment.

Methods Mol Biol 2017 ;1488:265-281

Department of Infection Genetics, Helmholtz Centre for Infection Research & University of Veterinary Medicine Hannover, Braunschweig, Niedersachsen, Germany.

Diversity Outbred (DO) mice are a multiparental advanced generation intercross population derived from eight inbred strains which are genetically very diverse. They are maintained as an outbred population using a randomized mating design. Thus DO mice represent an ideal population to map phenotypic traits. Here, we provide a case study in which male DO mice were exposed to benzene and phenotyped for the number of micronucleated reticulocytes. We provide step-by-step R scripts for the analysis of phenotypes, genotypes, mapping of resistance gene loci and identification of candidate genes.
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http://dx.doi.org/10.1007/978-1-4939-6427-7_12DOI Listing
January 2018

Deletion of Irf3 and Irf7 Genes in Mice Results in Altered Interferon Pathway Activation and Granulocyte-Dominated Inflammatory Responses to Influenza A Infection.

J Innate Immun 2017 4;9(2):145-161. Epub 2016 Nov 4.

Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany.

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.
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http://dx.doi.org/10.1159/000450705DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738875PMC
November 2017

Identification of specific residues in avian influenza A virus NS1 that enhance viral replication and pathogenicity in mammalian systems.

J Gen Virol 2016 09 12;97(9):2135-2148. Epub 2016 Jul 12.

Institute of Medical Virology, Justus Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany.

Reassortment of their segmented genomes allows influenza A viruses (IAV) to gain new characteristics, which potentially enable them to cross the species barrier and infect new hosts. Improved replication was observed for reassortants of the strictly avian IAV A/FPV/Rostock/34 (FPV, H7N1) containing the NS segment from A/Goose/Guangdong/1/1996 (GD, H5N1), but not for reassortants containing the NS segment of A/Mallard/NL/12/2000 (MA, H7N3). The NS1 of GD and MA differ only in 8 aa positions. Here, we show that efficient replication of FPV-NSMA-derived mutants was linked to the presence of a single substitution (D74N) and more prominently to a triple substitution (P3S+R41K+D74N) in the NS1MA protein. The substitution(s) led to (i) increased virus titres, (ii) larger plaque sizes and (iii) increased levels and faster kinetics of viral mRNA and protein accumulation in mammalian cells. Interestingly, the NS1 substitutions did not affect viral growth characteristics in avian cells. Furthermore, we show that an FPV mutant with N74 in the NS1 (already possessing S3+K41) is able to replicate and cause disease in mice, demonstrating a key role of NS1 in the adaptation of avian IAV to mammalian hosts. Our data suggest that (i) adaptation to mammalian hosts does not necessarily compromise replication in the natural (avian) host and (ii) very few genetic changes may pave the way for zoonotic transmission. The study reinforces the need for close surveillance and characterization of circulating avian IAV to identify genetic signatures that indicate a potential risk for efficient transmission of avian strains to mammalian hosts.
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http://dx.doi.org/10.1099/jgv.0.000542DOI Listing
September 2016

Genetically diverse CC-founder mouse strains replicate the human influenza gene expression signature.

Sci Rep 2016 05 19;6:26437. Epub 2016 May 19.

University of Tennessee Health Science Center, Memphis, Tennessee, United States of America.

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.
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http://dx.doi.org/10.1038/srep26437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4872221PMC
May 2016

Respiratory Mucosal Proteome Quantification in Human Influenza Infections.

PLoS One 2016 18;11(4):e0153674. Epub 2016 Apr 18.

University of Tennessee Health Science Center, Department of Microbiology, Immunology and Biochemistry, Memphis, United States of America.

Respiratory influenza virus infections represent a serious threat to human health. Underlying medical conditions and genetic make-up predispose some influenza patients to more severe forms of disease. To date, only a few studies have been performed in patients to correlate a selected group of cytokines and chemokines with influenza infection. Therefore, we evaluated the potential of a novel multiplex micro-proteomics technology, SOMAscan, to quantify proteins in the respiratory mucosa of influenza A and B infected individuals. The analysis included but was not limited to quantification of cytokines and chemokines detected in previous studies. SOMAscan quantified more than 1,000 secreted proteins in small nasal wash volumes from infected and healthy individuals. Our results illustrate the utility of micro-proteomic technology for analysis of proteins in small volumes of respiratory mucosal samples. Furthermore, when we compared nasal wash samples from influenza-infected patients with viral load ≥ 2(8) and increased IL-6 and CXCL10 to healthy controls, we identified 162 differentially-expressed proteins between the two groups. This number greatly exceeds the number of DEPs identified in previous studies in human influenza patients. Most of the identified proteins were associated with the host immune response to infection, and changes in protein levels of 151 of the DEPs were significantly correlated with viral load. Most important, SOMAscan identified differentially expressed proteins heretofore not associated with respiratory influenza infection in humans. Our study is the first report for the use of SOMAscan to screen nasal secretions. It establishes a precedent for micro-proteomic quantification of proteins that reflect ongoing response to respiratory infection.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153674PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4835085PMC
September 2016