Application of microRNAs in the prevention and control of porcine reproductive and respiratory syndrome: From mechanisms to clinical translation potential.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen that threatens the global swine industry. Although it was first identified in 1987, no highly effective vaccines or antiviral drugs are currently available. MicroRNAs (miRNAs) are a major class of post-transcriptional regulators that modulate PRRSV replication. In this review, we summarize recent advances in miRNA-mediated regulation of PRRSV replication. About 30 inhibitory miRNAs and 12 proviral miRNAs have been reported to regulate PRRSV infection, of which six have been validated in vivo. We further discuss the potential of miRNAs as antiviral strategies, including both the direct delivery of antiviral miRNAs and the antagonism of proviral miRNAs. For prevention, we highlight miRNA-mediated attenuation of live PRRSV vaccines and modulation of host susceptibility. In addition, we examine the potential of miRNAs as biomarkers for PRRSV infection. We also discuss the major challenges facing clinical translation and the potential research directions. Taken together, this review aims to facilitate the early application of miRNA-based approaches for PRRSV prevention and control.