MicroRNA-182 inhibits rat ovarian granulosa cell apoptosis by targeting Smad7 in polycystic ovarian syndrome

Dysfunction of granulosa cells may contribute to the aberrant folliculogenesis observed in polycystic ovary syndrome (PCOS). MicroRNAs (miRNAs) are highly conserved, small RNA molecules with 19-25 nucleotides in length that post transcriptionally regulate gene expression, involved in many developmental processes, including cell differentiation and apoptosis. Recently, miR-182 was reported to be downregulated in dihydrotestosterone (DHT)-induced rat PCOS model. However, the role of miR-182 in PCOS is still unclear. In this study, we aimed to reveal the role and regulating mechanism of miR-182 in granulosa cell apoptosis. We performed flow cytometry and quantitative Real-Time PCR (qRT-PCR) to detect the effects of DHT on apoptosis and miR-182 expression in granulosa cells, and found that DHT promotes granulosa cell apoptosis and high-concentration DHT inhibits miR-182 expression. We also investigated the role of miR-182, and found that miR-182 inhibits granulosa cell apoptosis. Bioinformatics identified Smad7 as a potential miR-182 target. Luciferase assays, mRNA and protein expression analysis, and flow cytometry assays confirmed that Smad7 is the functional target of miR-182. Taken together, these results suggest that miR-182 inhibits granulosa cell apoptosis by targeting Smad7, which provides a new insight into the mechanism of PCOS in mammals.