Project description:Infection with a single influenza A virus (IAV) is only rarely sufficient to initiate productive infection. Here, we exploit both single cell approaches and whole-animal systems to show that the extent of IAV reliance on multiple infection varies with virus strain and host species. Influenza A/guinea fowl/HK/WF10/99 (H9N2) [GFHK99] virus exhibits strong dependence on collective interactions in mammalian systems. This reliance focuses viral progeny production within coinfected cells and therefore results in frequent genetic exchange through reassortment. In contrast, GFHK99 virus has greatly reduced dependence on multiple infection in avian systems, indicating a role for host factors in viral collective interactions. Genetic mapping implicated the viral polymerase as a major driver of multiple infection dependence. Mechanistically, quantification of incomplete viral genomes showed that their complementation only partly accounts for the observed reliance on coinfection. Indeed, even when all polymerase components are detected in single cell mRNA sequencing, robust polymerase activity of GFHK99 virus in mammalian cells is reliant on multiple infection. In sum, IAV collective interactions not only augment reassortment, but can also overcome species-specific barriers to infection. These findings underscore the importance of virus-virus interactions in IAV infection, evolution and emergence. We used a single-cell sequencing platform (10x Genomics) to elucidate the differential infection rate of an avian influenza A virus on an avian cell line (DF1) and a mammalian (MDCK) cell line. Our work on IAV reassortment has raised new questions about the fundamental strategies that drive influenza virus evolution. Our data indicate that a large majority of influenza virus genomesare incomplete within cells, comprising less than the eight complete segments normally found in a replication competent infectious viral particle. This led us to ask: what underlying mechanisms give rise to incomplete genomes? What constitute an infectious unit? What are the implications for viral diversification, evolution and spread. By addressing these questions, we will advance he field by deepening our understanding how viral infections are initiated and propagated.
Project description:WGS and WGBS data from monocyte-derived macrophages that were infected with Influenza A virus strain PR8WT, or a matching non-infected control.
Project description:RNA-seq, ATAC-seq and ChIPmentation data from monocyte-derived macrophages that were infected with Influenza A virus strain PR8WT, or a matching non-infected control.
Project description:While a common symptom of influenza and coronavirus disease 2019 (COVID-19) is fever, its physiological role on host resistance to viral infection remains less clear. Here, we demonstrate that exposure of mice to the high ambient temperature of 36 °C increase host resistance to viral pathogens including influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High heat-exposed mice increase basal body temperature over 38 °C to enable more bile acids production in a gut microbiota-dependent manner. The gut microbiota-derived deoxycholic acid (DCA) and its plasma membrane-bound receptor Takeda G-protein-coupled receptor 5 (TGR5) signaling increase host resistance to influenza virus infection by suppressing virus replication and neutrophil-dependent tissue damage. Furthermore, the DCA and its nuclear farnesoid X receptor (FXR) agonist protect Syrian hamster from lethal SARS-CoV-2 infection. Moreover, we demonstrate that certain bile acids are reduced in the plasma of COVID-19 patients who developed moderate I/II disease compared with minor illness group. These findings uncover an unexpected mechanism by which virus-induced high fever increases host resistance to influenza virus and SARS-CoV-2 in a gut microbiota-dependent manner.
Project description:While a common symptom of influenza and coronavirus disease 2019 (COVID-19) is fever, its physiological role on host resistance to viral infection remains less clear. Here, we demonstrate that exposure of mice to the high ambient temperature of 36 °C increase host resistance to viral pathogens including influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). High heat-exposed mice increase basal body temperature over 38 °C to enable more bile acids production in a gut microbiota-dependent manner. The gut microbiota-derived deoxycholic acid (DCA) and its plasma membrane-bound receptor Takeda G-protein-coupled receptor 5 (TGR5) signaling increase host resistance to influenza virus infection by suppressing virus replication and neutrophil-dependent tissue damage. Furthermore, the DCA and its nuclear farnesoid X receptor (FXR) agonist protect Syrian hamster from lethal SARS-CoV-2 infection. Moreover, we demonstrate that certain bile acids are reduced in the plasma of COVID-19 patients who developed moderate I/II disease compared with minor illness group. These findings uncover an unexpected mechanism by which virus-induced high fever increases host resistance to influenza virus and SARS-CoV-2 in a gut microbiota-dependent manner.
Project description:A novel avian-origin H7N9 influenza A virus (IAV) emerged in China in early 2013 causing mild to lethal human respiratory infections. H7N9 originated from multiple reassortment events between avian viruses and carries genetic markers of human adaptation. Determining whether H7N9 induces a host-response closer to human or avian IAV is important to better characterize this emerging virus. Here we compared the human lung epithelial cell response to infection with A/Anhui/01/13 (H7N9) or highly pathogenic avian-origin H5N1, H7N7, or human seasonal H3N2 IAV.
Project description:The purpose of this experiment was to understand the pathogenic role of individual 1918 genes on the host response to the 1918 pandemic influenza virus. We examined reassortant avian viruses nearly identical to the pandemic 1918 virus (1918-like avian virus) carrying either the 1918 HA or PB2 gene. Both genes enhanced 1918-like avian virus replication, but only the mammalian host adaptation of the 1918-like avian virus through reassortment of the 1918 PB2 led to increased lethality in mice. We demonstrate that 1918 PB2 enhances immune and inflammatory responses concomitant with increased cellular infiltration in the lung. We also show that 1918 PB2 expression results in the repression of both canonical and non-canonical Wnt signaling pathways which are crucial for inflammation mediated lung regeneration and repair.
Project description:Different respiratory viruses induce virus-specific gene expression in the host. Recent evidence, including those presented here, suggests that genetically related isolates of influenza virus induce strain specific host gene regulation in several animal models. Here, we identified systemic strain-specific gene expression signatures in ferrets infected with pandemic influenza A/California/07/2009, A/Mexico/4482/2009 or seasonal influenza A/Brisbane/59/2007. Using uncorrelated shrunken centroid classification, we were able to accurately identify the infecting influenza strain with a combined gene expression profile of 10 selected genes, independent of the severity of disease. Another gene signature, consisting of 7 genes, could classify samples based on lung pathology. Furthermore, we identified a gene expression profile consisting of 31 probes that could classify samples based on both strain and severity of disease. Thus, we show that expression-based analysis of non-infected tissue enables distinction between genetically related influenza viruses as well as lung pathology. These results open for development of alternative tools for influenza diagnostics.