Expression data from A549 cells infected with H1N1 virus

Fibroblast growth factor (FGF) 2 (FGF2 or basic FGF) mediates a wide range of biological functions, such as regulating proliferation, angiogenesis, migration, differentiation and injury repair. However, the roles of FGF2 and the underlying mechanisms of action in influenza virus (IAV) -induced lung injury remain largely unexplored. In this study, we firstly report miR-194 expression is significantly decreased in A549 cells following influenza virus A/Beijing/501/2009 (BJ501) infection. MiR-194 directly targeting FGF2, a novel antiviral regulator, could suppress FGF2 expression both in mRNA and protein levels. Overexpression miR-194 facilitate IAV replication via negatively regulating type I IFN production, and reintroduction of FGF2 abrogates miR-194-induced effects on promoting IAV replication. On the contrary, inhibition of miR-194 alleviate IAV induced lung injury via promoting type I IFNs antiviral activities in vivo. Importantly, contrary to FGF2 activated RIG-I signaling pathway, miR-194 suppressed TBK1 and IRF3 phosphorylation. Taken together, our findings demonstrated that miR-194-FGF2 axis play a vital role in IAV-induced lung injury, and miR-194 antagonism might be as a potential therapeutic target during IAV infection. Fibroblast growth factor (FGF) 2 (FGF2 or basic FGF) mediates a wide range of biological functions, such as regulating proliferation, angiogenesis, migration, differentiation and injury repair. However, the roles of FGF2 and the underlying mechanisms of action in influenza virus (IAV) -induced lung injury remain largely unexplored. In this study, we firstly report miR-194 expression is significantly decreased in A549 cells following influenza virus A/Beijing/501/2009 (BJ501) infection. MiR-194 directly targeting FGF2, a novel antiviral regulator, could suppress FGF2 expression both in mRNA and protein levels. Overexpression miR-194 facilitate IAV replication via negatively regulating type I IFN production, and reintroduction of FGF2 abrogates miR-194-induced effects on promoting IAV replication. On the contrary, inhibition of miR-194 alleviate IAV induced lung injury via promoting type I IFNs antiviral activities in vivo. Importantly, contrary to FGF2 activated RIG-I signaling pathway, miR-194 suppressed TBK1 and IRF3 phosphorylation. Taken together, our findings demonstrated that miR-194-FGF2 axis play a vital role in IAV-induced lung injury, and miR-194 antagonism might be as a potential therapeutic target during IAV infection. A549 cells were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to obtain miRNA expression at different stage of influenza H1N1 virus infection in order to increase the temporal resolution of expression profiles. To that end, we selected infected A549 at four time-points: non-infected A549, A549 of 24h post infection, A549 of 48h post infection, A549 of 72h post infection.