Identification of miRNomes reveals ssc-miR-30d-R_1 as a potential therapeutic target for PRRS viral infection

Porcine reproductive and respiratory syndrome virus (PRRSV) is known to cause reproductive disorders, such as abortion, in pregnant sows as well as immunosuppressive respiratory complications, leading to severe respiratory tract infections in young pigs. In this study, an in-depth analysis of the miRNomes in mock- and virus-infected pig lungs was carried out. We found that highly expressed ssc-miR-30d-R_1 was decreased in infected lungs, and reduced levels were significantly correlated with infection by PRRSV. Moreover, ssc-miR-30d-R_1 was shown to target Toll-like receptor 4 (TLR4) and to suppress the production of immune cytokines through inhibition of the TLR4/MyD88/NF-κB pathway. ssc-miR-30d-R_1 significantly reduced viral infections and pathological changes in pig lungs in vivo. Our current study reveals the miRNomes of PRRSV-infected pig lungs and indicates that ssc-miR-30d-R_1 is potential therapeutic agent for controlling PRRSV infection.