Project description:Influenza A virus (IAV) is a human respiratory pathogen that causes yearly global epidemics, and sporadic pandemics due to human adaptation of pathogenic strains. Efficient replication of IAV in different species is, in part, dictated by its ability to exploit the genetic environment of the host cell. To investigate IAV tropism in human cells, we evaluated the replication of IAV strains in a diverse subset of epithelial cell lines. HeLa cells were refractory to growth of human H1N1 and H3N2, and low pathogenic avian influenza (LPAIs) viruses. Interestingly, a human isolate of the highly pathogenic avian influenza (HPAI) virus H5N1 successfully propagated in HeLa cells to levels comparable to a human lung cell line. Heterokaryon cells generated by fusion of HeLa and permissive cells supported H1N1 growth, suggesting the absence of a host factor(s) required for replication of H1N1, but not H5N1, in HeLa cells. The absence of this factor(s) was mapped to reduced nuclear import, replication, and translation, and deficient viral budding. Using reassortant H1N1:H5N1 viruses, we found that the combined introduction of nucleoprotein (NP) and hemagglutinin (HA) from H5N1 was necessary and sufficient to enable H1N1 growth. Overall, this study suggests the absence of one or more cellular factors in HeLa cells that results in abortive replication of H1N1, H3N2, and LPAI viruses, but can be circumvented upon introduction of H5N1 NP and HA. Further understanding of the molecular basis of this restriction will provide important insights into virus-host interactions that underlie IAV pathogenesis and tropism.
Project description:In this study, we performed a miRNA global profiling in human lung epithelial cells (A549) infected by two different subtypes of human influenza A viruses (H1N1 and H3N2).
Project description:In this study, we performed a miRNA global profiling in human lung epithelial cells (A549) infected by two different subtypes of human influenza A viruses (H1N1 and H3N2). A549 cells were either mock-infected or infected at a multiplicity of infection (MOI) of 1 with H1N1 or H3N2 viruses, and total RNAs were isolated at 24 hours post-infection (hpi). An MOI of 1 was performed to ensure that 100% of the cells were infected at 24 hpi, a strategy that we have previously validated and used for a transcriptional profiling study of infected cells (Josset et al. , 2010). The purified RNAs were subjected to reverse transcription using a pool of miRNA RT primers (Human pool A v2.1, Applied Biosystems) and subsequently amplified and quantified by RT-qPCR in a TaqMan array MicroRNA card (Applied biosystems).
Project description:The circulation of seasonal influenza A viruses (IAVs) in humans relies on effective evasion and subversion of the host immune response. While the evolution of seasonal H1N1 and H3N2 viruses to avoid humoral immunity is well characterized, relatively little is known about the evolution of innate immune antagonism phenotypes in these viruses. Numerous studies have established that only a small subset of infected cells are responsible for initiating the type I and type III interferon (IFN) response during IAV infection, emphasizing the importance of single cell studies to accurately characterize the IFN response during infection. We developed a flow cytometry-based method to examine transcriptional changes in IFN and interferon stimulated gene (ISG) expression at the single cell level. We observed that NS segments derived from seasonal H3N2 viruses are more efficient at antagonizing IFN signaling but less effective at suppressing IFN induction, compared to the pdm2009 H1N1 lineage. We compared a collection of NS segments spanning the natural history of the current seasonal IAV lineages, and demonstrate long periods of stability in IFN antagonism potential, punctuated by occasional phenotypic shifts. Altogether, our data reveal significant differences in how seasonal and pandemic H1N1 and H3N2 viruses antagonize the human IFN response at the single cell level.
Project description:Analysis of gene expression in macrophages infected with influenza A virus or Mock and treated with the VX-787 to investigate the effects VX-787 have on transcriptional response in human macrophages. Human macrophages were infected with influenza A/WSN/1933(H1N1) or A/Udorn/307/72(H3N2) viruses, or non-infected (Mock). 10nM VX-787 was treated to WSN, Udorn or Mock infected cells, repectively.
Project description:Lung infection by influenza A viruses is a common cause of disease exacerbations in patients with chronic obstructive pulmonary disease (COPD), however, this process is difficult to study in human patients. Here we used a microfluidic human lung airway-on-a-chip (Airway Chip) lined by primary human bronchial epithelium interfaced with primary human pulmonary microvascular endothelium to model this process in vitro. Airway Chips containing bronchial epithelial cells from COPD patients successfully replicated the increased sensitivity to the lung airway to infection by both influenza H1N1 and H3N2 viruses compared to chips lined by epithelium from healthy donors, including enhanced viral loads and increased production of inflammatory cytokines. Transcriptomics analysis of the healthy and COPD epithelium following infection with influenza H1N1 virus on-chip resulted in identification of several novel markers of COPD
Project description:Airway epithelial cells are the initial site of infection with influenza viruses. The innate immune responses of airway epithelial cells to infection have the potential to limit virus replication and induce effective adaptive immune responses. However, relatively little is known about the importance of this innate anti-viral response to infection. Avian influenza viruses are a potential source of future pandemics, therefore it is critical to examine the effectiveness of the host anti-viral system to different influenza viruses. We used a human influenza (H3N2) and a low pathogenic avian influenza (H11N9) to assess and compare the anti-viral responses of bronchial epithelial cells (BECs). After infection, the H3N2 virus replicated more effectively than the H11N9 strain in BECs. This was not due to differential expression of different sialic acid residues on BECs but was attributed to the interference of the host anti-viral responses by H3N2. The H3N2 strain induced a delay in anti-viral signaling and impaired release of type I and type III interferons (IFNs) compared to the H11N9 virus. We then transfected the gene encoding for non-structural (NS) 1 protein into the BECs and the H3N2 NS1 induced a greater inhibition of anti-viral responses compared to the H11N9 NS1. While the low pathogenic avian influenza virus was capable of infecting BECs, the human influenza virus replicated more effectively than avian influenza virus in BECs and this may be at least in part due to a differential ability of the two NS1 proteins to inhibit anti-viral responses. This suggests that the subversion of human anti-viral responses may be an important requirement for influenza viruses to adapt to the human host and induce disease.
Project description:Influenza A virus is mainly transmitted through the respiratory route and can cause severe illness in humans. Proteins encoded by influenza A virus can interact with cellular factors and dysregulate host biological processes to facilitate viral replication and pathogenicity. The influenza viral PA protein is not only a subunit of influenza viral polymerase but also a virulence factor involved in pathogenicity during infection. To explore the role of the influenza virus PA protein in regulating host biological processes, we conducted immunoprecipitation and LC-MS/MS to globally identify cellular factors that interact with the PA proteins of the influenza A H1N1, 2009 pandemic H1N1, H3N2, and H7N9 viruses. The results demonstrated that proteins located in the mitochondrion, proteasome, and nucleus are associated with the PA protein. We further discovered that the PA protein is located in mitochondria by immunofluorescence and mitochondrial fractionation and that overexpression of the PA protein reduces mitochondrial respiration. In addition, our results revealed the interaction between PA and the mitochondrial matrix protein PYCR2 and the antiviral role of PYCR2 during influenza A virus replication. Moreover, we found that the PA protein could also trigger autophagy and disrupt mitochondrial homeostasis. Overall, our research revealed the impacts of the influenza A virus PA protein on mitochondrial function and autophagy.
Project description:Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and other respiratory viruses -Coronavirus OC43, Coronavirus 229E, Influenza A/H1N1, Influenza A/H3N2, Influenza B, Respiratory Syncytial Virus RSV A and RSV B - were analysed by bottom-up proteomics of viral cultures. High coverage of viral proteins was acheived after culturing in serum-free conditions when compared to cultures grown using standard conditions including 2% fetal bovine serum.
Project description:While pandemic 2009 H1N1 influenza A viruses were responsible for numerous severe infections in humans, these viruses do not typically cause corresponding severe disease in mammalian models. However, the generation of a virulent 2009 H1N1 virus following serial lung passage in mice has allowed for the modeling of human lung pathology in this species. Genetic determinants of mouse-adapted 2009 H1N1 viral pathogenicity have been identified, but the molecular and signaling characteristics of the host response following infection with this adapted virus have not been described. Here, we compared the gene-expression response following infection of mice with A/CA/04/2009 (CA/04) or the virulent mouse-adapted strain (MA-CA/04). Microarray analysis revealed that increased pathogenicity of MA-CA/04 was associated with: (1) early and sustained inflammatory and interferon response that could be driven in part by interferon regulatory factors (IRFs) and increased NF-kappaB activation, as well as inhibition of the negative regulator TRIM24, (2) early and persistent infiltration of immune cells, including inflammatory macrophages, and (3) the absence of activation of lipid metabolism later in infection, that may be mediated by nuclear receptors inhibition, including PPARG, HNF1A and 4A, with pro-inflammatory consequences. Further investigation of these signatures in the host response to other H1N1 viruses of varied pathogenicity confirmed their general relevance for virulence of influenza virus and suggested that lung response to MA-CA/04 virus was similar to that following lethal H1N1 r1918 influenza virus. This study links for the first time differential activation of IRFs, nuclear receptors, and macrophage infiltration with influenza virulence in vivo.