MicroRNA-135a Regulates VEGFC Expression and Promotes Luteinized Granulosa Cell Apoptosis in Polycystic Ovary Syndrome

Androgen is known to regulate microRNA-135a (miR-135a) and can be regulated by androgen, suggesting that it may contribute to polycystic ovary syndrome (PCOS) with hyperandrogenism. However, its roles and mechanisms of action in PCOS are unknown. In this study, the role and molecular mechanisms underlying miR-135a in granulosa cells (GCs) in PCOS were evaluated. miR-135a expression was upregulated in patients with PCOS and in GCs isolated from patients compared with that in the respective controls (P < 0.01), as determined by RT-qPCR. The overexpression of miR-135a inhibited GC proliferation and induced GC apoptosis, as observed by CCK-8 assay and apoptosis assay. Furthermore, miR-135a overexpression increased the expression of double-strand break maker, gamma H2AX, as confirmed by western blotting. Our results further suggest that these effects were mediated via downregulation of vascular endothelial growth factor C (VEGFC), which was identified as a direct target of miR-135a. Moreover, levels of VEGFC and miR-135a expression showed a negative correlation. These findings indicate that miR-135a promotes apoptosis and the DNA damage response in GCs in PCOS, likely via VEGFC signaling. This study provides novel insights into GC dysregulation in PCOS and suggests that miR-135a is a promising therapeutic target for PCOS treatment.