Shrimp miR-12 Suppresses White Spot Syndrome Virus Infection by Synchrously Tiggering Antiviral Phagocytosis and Apoptosis Pathways

Growing evidence has indicated that the innate immune system can be regulated by microRNAs (miRNAs). However, the mechanism underlying miRNA-mediated simultaneous activation of multiple immune pathways remains unknown. To address this issue, the role of host miR-12 in shrimp (Marsupenaeus japonicus) antiviral immune responses was characterized in the present study. The results indicated that miR-12 participated in virus infection, host phagocytosis, and apoptosis in defense against white spot syndrome virus invasion. miR-12 could simultaneously trigger phagocytosis, apoptosis, and antiviral immunity through the synchronous downregulation of the expression of shrimp genes [ PTEN (phosphatase and tensin homolog) and BI-1(transmembrane BAX inhibitor motif containing 6)] and the viral gene (wsv024). Further analysis showed that miR-12 could synchronously mediate the 5'-3' exonucleolytic degradation of its target mRNAs, and this degradation terminated in the vicinity of the 3' untranslated region sequence complementary to the seed sequence of miR-12. Therefore, the present study showed novel aspects of the miRNA-mediated simultaneous regulation of multiple immune pathways.