[Transglutaminase 2 inhibits the proliferation of H1 subtype influenza virus in MDCK cells]

Transglutaminase 2 (TGM2) is a ubiquitous multifunctional protein, which is related to the adhesion of different cells and tumor formation. Previous studies found that TGM2 is involved in the interaction between host cells and viruses, but the effect of TGM2 on the proliferation of influenza virus in cells has not been reported. To explore the effect of TGM2 during H1N1 subtype influenza virus infection, a stable MDCK cell line with TGM2 overexpression and a knockout cell line were constructed. The mRNA and protein expression levels of NP and NS1 as well as the virus titer were measured at 48 hours after pot-infection with H1N1 subtype influenza virus. The results showed that overexpression of TGM2 effectively inhibited the expression of NP and NS1 genes of H1N1 subtype influenza virus, while knockout of TGM2 up-regulated the expression of the NP and NS1 genes, and the expression of the NP at protein level was consistent with that at mRNA level. Virus proliferation curve showed that the titer of H1N1 subtype influenza virus decreased significantly upon TGM2 overexpression. On the contrary, the virus titer in TGM2 knockout cells reached the peak at 48 h, which further proved that TGM2 was involved in the inhibition of H1N1 subtype influenza virus proliferation in MDCK cells. By analyzing the expression of genes downstream of influenza virus response signaling pathway, we found that TGM2 may inhibit the proliferation of H1N1 subtype influenza virus by promoting the activation of JAK-STAT molecular pathway and inhibiting RIG-1 signaling pathway. The above findings are of great significance for revealing the mechanism underlying the interactions between host cells and virus and establishing a genetically engineering cell line for high-yield influenza vaccine production of influenza virus.