MiR-338* suppresses fibrotic pathogenesis in pulmonary fibrosis through targeting LPA1.

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease involving pulmonary injury associated with tissue repair, dysfunction and fibrosis. MicroRNAs (miRNAs), as gene regulators, are assumed to regulate about one third of genes and thus play important roles in cellular functions including proliferation, growth, differentiation and apoptosis. Recent studies have indicated that some miRNAs may play critical roles in the pathogenesis of pulmonary fibrosis. In this study, we found that miR-338*(miR-338-5p), which has been found to be associated with tumor progression, was down-regulated in fibroblasts and TGF-β-induced lung fibrotic tissues. Over-expression of miR-338* can partly prevent the fibrotic process induced by TGF-β. Moreover, LPA1 was proven to be a downstream target of miR-338*. Lentivirus-mediated over-expression of miR-338* can alleviate lung fibrosis induced by bleomycin in mice. Taken together, our results suggest that miR-338* attenuates the pathogenesis of pulmonary fibrosis through targeting LPA1. Thus, miR-338* can be a potential therapeutic target for the treatment of IPF.