Enterovirus 71 inhibited interferon signaling by downregulating expression of IRF9 / 中国免疫学杂志

ABSTRACT

Objective:To explore the mechanism of EV71 antagonizing IFN signaling pathway.Methods: RD cells were infected or un-infected with EV71.Then the cells were treated with or without IFN-β.The four groups (the control group,the EV71 group,the IFN-β group,the EV71+IFN-β group) were detected by molecular biology techniques.The expression of interferon stimulated genes (ISGs) were detected by Real-time PCR,while the protein levels of STAT1 and IRF9 were examined by Western blot assay.By preparing the cytosolic and nuclear fractions,the translocation of p-STAT1 was monitored through Western blot assay.Results:Compared with the IFN-β group,the mRNA level of OAS1,MX1 and ISG54 in the EV71+IFN-β group was down regulated by 47%, 50% and 48%,respectively,indicating that EV71 inhibited the expression of ISGs.The results also showed that EV71 did not effect the protein level and phosphorylation of STAT1.Moreover,we found that p-STAT1 was translocated into neuclear in IFN-β group,while p-STAT1 was located in the cytoplasm in the EV71+IFN-β group.And the expression of IRF9 was boviously down regulated in EV71+IFN-β group compared with that in IFN-β group,suggesting that EV71 blocked the expression of IRF9 induced by IFN-β.Conclusion:EV71 inhibited the IFN signaling pathway by downregulating the expression of IRF9 induced by IFN-β.