Inducible microRNA-590-5p inhibits host antiviral response by targeting the soluble interleukin-6 (IL6) receptor

MicroRNA (miR)-590-5p has been identified as an important regulator of some signaling pathways such as cell proliferation and tumorigenesis. However, little is known about its role during viral infection. Here, we report that miR-590-5p was significantly induced by various viruses and effectively potentiated virus replication in different viral infection systems. Furthermore, miR-590-5p substantially attenuated the virus-induced expression of type I and type III interferons (IFNs) and inflammatory cytokines, resulting in impaired downstream antiviral signaling. Interleukin-6 receptor (IL6R) was identified as a target of miR-590-5p. Interestingly, the role of miR-590-5p in virus-triggered signaling was abolished in IL6R knockout cells, and this could be rescued by restoring the expression of the soluble IL6R (sIL6R) but not the membrane-bound IL6R (mIL6R), suggesting that sIL6R is indispensable for miR-590-5p in modulating the host antiviral response. Furthermore, miR-590-5p down-regulated endogenous sIL6R and mIL6R expression through a translational repression mechanism. These findings thus uncover a previously uncharacterized role and the underlying mechanism of miR-590-5p in the innate immune response to viral infection.