MicroRNA-376b-3p Promotes Porcine Reproductive and Respiratory Syndrome Virus Replication by Targeting Viral Restriction Factor TRIM22.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major economically significant pathogen and has evolved several strategies to evade host antiviral response and provide favorable conditions for survival. In the present study, we demonstrated that a host microRNA, miR-376b-3p, was upregulated by PRRSV infection through the viral components, nsp4 and nsp11, and that miR-376b-3p can directly target tripartite motif-containing 22 (TRIM22) to impair its anti-PRRSV activity, thus facilitating the replication of PRRSV. Meanwhile, we found that TRIM22 induced degradation of the nucleocapsid protein (N) of PRRSV by interacting with N protein to inhibit PRRSV replication, and further study indicated that TRIM22 could enhance the activation of the lysosomal pathway by interacting with LC3 to induce lysosomal degradation of N protein.