P-STAT1Regulates The Influenza A Virus Replication And Inflammatory Response

The researh found that, the activated of several phosphorylated proteins are essential for virus replication which may be a potential antiviral target. Herein, a quantitative phosphoproteomic analysis of A549cells2h after infection with three different subtypes influenza A virus (H1N1, H5N1, H7N2) was performed. We identified1326different phosphoprotein and involved in the innate immune, apoptosis, and transcription. The transcription factor STAT1was highly activated, so we investigated its function during influenza A virus infection. And investigate whether this protein participates in the viral replication like the c-jun and NF-κB protein.Firstly we detected the relationship between STAT1activation and H5N1virus infection in A549. The results indicated that the STAT1activation start to occur before2h post infection (p.i.), the peak value occurred on4h-8h p.i., which droped rapidly on continued more than12hours (from8h p.i. to12h p.i.). Meanwhile, we detected the viral propagation trend of H5N1virus and IFNβ production in A549, and didn’t found downtrend. Summarize the results, we found STAT1activated and play it’s biological effect occurred at the early stage on H5N1infection (0-12h). Unexpectedly, upon inhibition of p-STATluse the FLUD, titers of progeny virus and viral protein synthesis were both reduced. The results of time course experiment suggested that the STATl inhibitor inhibited an early progeny step in viral infection (<3h). Levels of influenza virus genomic RNA (vRNA), but not cRNA or mRNA, were specifically reduced by FLUD in virus-infected cells, indicating that p-STAT1affects vRNA synthesis. Concomitantly, there was reduced expression of inflammatory cytokines in p-STAT01inhibited cells. When we administered STAT1-specific siRNA during virus infection, we observed similarly reduced virus replication. In vivo, suppression of p-STAT1improved the survival of H5N1virus-infected mice. Additionally, the pulmonary inflammatory response and viral burden were also reduced in this group. Thus, our data demonstrated a critical role for p-STAT1in influenza virus replication and subsequent inflammatory responses.Influenza in humans is often accompanied by gastroenteritis-like symptoms such as diarrhea and abdominal pain nausea. We explored the occurrence of gastroenteritis-like symptoms using a mouse model infected with three different subtypes (H1N1, H5N1, H7N2) influenza A virus (IAV). We found that mice infecting with three different influenza A viruses induced obvious intestinal injury especially infected with the H5N1and H7N2virus. The two avian influenza A virus H5N1and H7N2could be detected in the small intestine while the human original HIN1couldn’t. The sialic acid (SA) receptor section stained research demonstrated that the small intestine have the SA a2,3Gal receptor instead of SA a2,6Gal receptor which preferentially bind the avian IAV. Additionally, the number of goblet and slgA cells in the small intestine increased, whereas CD4-and CD8T cells decreased in all infected mice except for CD8-T cells increased obviously in H7N2infected mice. These data suggest that the respiratory IAV infection, especially avian IAV, could cause the small intestine structural damage and modify the local immune response, which may be account for the gastroenteritis-like symptoms induced by IAV infection.