Project description:Viral infection can dramatically alter a cell's transcriptome. However, these changes have mostly been studied by bulk measurements on many cells. Here we use single-cell mRNA sequencing to examine the transcriptional consequences of influenza virus infection. We find extremely wide cell-to-cell variation in production of viral gene transcripts -- viral transcripts compose less than a percent of total mRNA in many infected cells, but a few cells derive over half their mRNA from virus. Some infected cells fail to express at least one viral gene, and this gene absence partially explains variation in viral transcriptional load. Despite variation in total viral load, the relative abundances of viral mRNAs are fairly consistent across infected cells. Activation of innate immune pathways is rare, but some cellular genes co-vary in abundance with the amount of viral mRNA. Overall, our results highlight the complexity of viral infection at the level of single cells.
Project description:Viral infection outcomes are governed by the complex and dynamic interplay between the infecting virus population and the host response. It is increasingly clear that both viral and host cell populations are highly heterogeneous, but little is known about how this heterogeneity influences infection dynamics or viral pathogenicity. To dissect the interactions between influenza A virus (IAV) and host cell heterogeneity, we examined the combined host and viral transcriptomes of thousands of individual cells, each infected with a single IAV virion. We observed complex patterns of viral gene expression and the existence of multiple distinct host transcriptional responses to infection at the single cell level. We show that human H1N1 and H3N2 strains differ significantly in patterns of both viral and host anti-viral gene transcriptional heterogeneity at the single cell level. Our analyses also reveal that semi-infectious particles that fail to express the viral NS can play a dominant role in triggering the innate anti-viral response to infection. Altogether, these data reveal how patterns of viral population heterogeneity can serve as a major determinant of antiviral gene activation.
Project description:Influenza virus infection leads to global cardiac proteome remodeling during convalescence MTD project_description "Influenza virus infections lead to more than 500,000 hospitalizations in the U.S. every year. Patients with cardiovascular diseases have been shown to be at high risk of influenza mediated cardiac complications. Importantly, recent reports have provided clinical data supporting a direct link between laboratory-confirmed influenza virus infection and adverse cardiac events. However, the molecular mechanisms of how influenza virus infection induces detrimental cardiac changes, even after resolution of the pulmonary infection, is completely unknown.
Project description:Influenza virus infection leads to global cardiac proteome remodeling during convalescence MTD project_description "Influenza virus infections lead to more than 500,000 hospitalizations in the U.S. every year. Patients with cardiovascular diseases have been shown to be at high risk of influenza mediated cardiac complications. Importantly, recent reports have provided clinical data supporting a direct link between laboratory-confirmed influenza virus infection and adverse cardiac events. However, the molecular mechanisms of how influenza virus infection induces detrimental cardiac changes, even after resolution of the pulmonary infection, is completely unknown. We performed global quantitative proteomics as well as phosphoproteomics in this study.
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:Influenza virus infection leads to global cardiac proteome remodeling during convalescence MTD project_description "Influenza virus infections lead to more than 500,000 hospitalizations in the U.S. every year. Patients with cardiovascular diseases have been shown to be at high risk of influenza mediated cardiac complications. Importantly, recent reports have provided clinical data supporting a direct link between laboratory-confirmed influenza virus infection and adverse cardiac events. However, the molecular mechanisms of how influenza virus infection induces detrimental cardiac changes, even after resolution of the pulmonary infection, is completely unknown. Mixed lineage kinase domain-like protein (MLKL) is a pseudokinas that mediates necroptosis. We performed global quantitative proteomics as well as phosphoproteomics to understand its role in the heart in response to inflenza virus infection in this study.
Project description:Cells respond differently to influenza virus infection after already having been infected previously. Anlysis of cellular RNA after influenza virus infection
Project description:Viral infection perturbs host cells and can be used to uncover host regulatory mechanisms controlling both cell response and homeostasis. Here, using cell biological, biochemical and genetic tools, we reveal that influenza virus infection induces global transcriptional defects at the 3’-end of active host genes and RNA polymerase II (RNAPII) run-through into extragenic regions. This effect induces the biogenesis of aberrant RNAs (3’-extensions and host gene fusions) which ultimately causes global transcriptional downregulation of physiological transcripts, an effect that impacts antiviral response and virulence. We show that this phenomenon occurs with multiple strains of influenza virus and it is dependent on influenza NS1 protein expression. Mechanistically, pervasive RNAPII run-through can be modulated by SUMOylation of an intrinsically disordered region (IDR) of the NS1 expressed by the 1918 pandemic influenza virus. SUMOylation increases NS1 partitioning in nuclear granules and interference with the host transcriptional apparatus which result in augmentation of termination defects and a concomitant increase in global host gene shut off. Our data identify a general strategy used by influenza virus to suppress host gene expression and indicate that polymorphisms in IDRs of viral proteins, along with human genetic variation in enzymes that metabolize post-translational modifications, can determine the outcome of an infection. We thus propose that analysis of strain-specific determinant of pathogenesis can shed light on the molecular basis of virulence.