Project description:Zoonotic influenza A viruses of avian origin can cause severe disease in individuals, or even global pandemics, and thus pose a threat to human populations. Waterfowl and shorebirds are believed to be the reservoir for all influenza A viruses, but this has recently been challenged by the identification of novel influenza A viruses in bats. The major bat influenza A virus envelope glycoprotein, haemagglutinin, does not bind the canonical influenza A virus receptor, sialic acid or any other glycan, despite its high sequence and structural homology with conventional haemagglutinins. This functionally uncharacterized plasticity of the bat influenza A virus haemagglutinin means the tropism and zoonotic potential of these viruses has not been fully determined. Here we show, using transcriptomic profiling of susceptible versus non-susceptible cells in combination with genome-wide CRISPR-Cas9 screening, that the major histocompatibility complex class II (MHC-II) human leukocyte antigen DR isotype (HLA-DR) is an essential entry determinant for bat influenza A viruses. Genetic ablation of the HLA-DR α-chain rendered cells resistant to infection by bat influenza A virus, whereas ectopic expression of the HLA-DR complex in non-susceptible cells conferred susceptibility. Expression of MHC-II from different bat species, pigs, mice or chickens also conferred susceptibility to infection. Notably, the infection of mice with bat influenza A virus resulted in robust virus replication in the upper respiratory tract, whereas mice deficient for MHC-II were resistant. Collectively, our data identify MHC-II as a crucial entry mediator for bat influenza A viruses in multiple species, which permits a broad vertebrate tropism.
Project description:In recent years, the roles of microRNAs playing in the regulation of influenza viruses replication caused researchers' much attenion. However, much work focused on the interactions between human, mice or chicken microRNAs with human or avian influenza viruses rather than the interactions of swine microRNAs and swine influenza viruses. To investigate the roles of swine microRNAs playing in the regulation of swine influenza A virus replication, the microRNA microarray was performed to identify which swine microRNAs were involved in swine H1N1/2009 influenza A virus infection.
Project description:Human rhinovirus and influenza virus infections of the upper airway lead to colds and the flu and can trigger exacerbations of lower airway diseases including asthma and chronic obstructive pulmonary disease. Despite modest advances in the diagnosis and treatment of infections by these viruses, novel diagnostic and therapeutic targets are still needed to differentiate between the cold and the flu, since the clinical course of influenza can be severe while that of rhinovirus is usually more mild. In our investigation of influenza and rhinovirus infection of human respiratory epithelial cells, we used a systems approach to identify the temporally changing patterns of host gene expression from these viruses. After infection of human bronchial epithelial cells (BEAS-2B) with rhinovirus, influenza virus or co-infection with both viruses, we studied the time-course of host gene expression changes over three days. From these data, we constructed a transcriptional regulatory network model that revealed shared and unique host responses to these viral infections such that after a lag of 4-8 hours, most cell host responses were similar for both viruses, while divergent host cell responses appeared after 24-48 hours. The similarities and differences in gene expression after epithelial infection of rhinovirus, influenza virus, or both viruses together revealed qualitative and quantitative differences in innate immune activation and regulation. These differences help explain the generally mild outcome of rhinovirus infections compared to influenza infections which can be much more severe. Human bronchial epithelial cells (BEAS-2B) were infected with rhinovirus, influenza virus or both viruses and RNAs were then profiled at 10 time points (2, 4, 6, 8, 12, 24, 26, 48, 60 and 72hrs)
Project description:Periodic outbreaks of highly pathogenic avian H5N1 influenza viruses and the current H1N1 pandemic highlight the need for a more detailed understanding of influenza virus pathogenesis. To investigate the host transcriptional response induced by pathogenic influenza viruses, we used a functional-genomics approach to compare gene expression profiles in lungs from wild-type 129S6/SvEv and interferon receptor (IFNR) knockout mice infected with either the fully reconstructed H1N1 1918 pandemic virus (1918) or the highly pathogenic avian H5N1 virus Vietnam/1203/04 (VN/1203).