MicroRNA-30c Modulates Type I IFN Responses To Facilitate Porcine Reproductive and Respiratory Syndrome Virus...

Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen and has evolved several mechanisms to evade IFN-I responses. We report that a host microRNA, miR-30c, was upregulated by PRRSV via activating NF-κB and facilitated its ability to infect subject animals. Subsequently, we demonstrated that miR-30c was a potent negative regulator of IFN-I signaling by targeting JAK1, resulting in the enhancement of PRRSV infection. In addition, we found that JAK1 expression was significantly decreased by PRRSV and recovered when miR-30c inhibitor was overexpressed. Importantly, miR-30c was also upregulated by PRRSV infection in vivo, and miR-30c expression corresponded well with viral loads in lungs and porcine alveolar macrophages of PRRSV-infected pigs. Our findings identify a new strategy taken by PRRSV to escape IFN-I-mediated antiviral immune responses by engaging miR-30c and, thus, improve our understanding of its pathogenesis.