miR-199a-5p stimulates ovarian granulosa cell apoptosis in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder and one of the most common causes of infertility in women. PCOS patients have been found with dysregulated miRNA, which is indicative of their roles as noninvasive biomarkers and novel therapeutic targets in PCOS. Herein, this study sets out to explore the mechanism of action of miR-199a-5p in PCOS in relation to the janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway via Wilms' tumor 1 (WT1) regulation in a rat model of PCOS. The expression of miR-199a-5p was highly expressed in ovarian cortical tissues and serum of PCOS patients, as examined by RT-qPCR. Ovarian granulosa cells (GCs) were harvested from PCOS rat model, followed by subsequent purification. Gain- and loss-of-function experiments of miR-199a-5p were performed to determine its functions in PCOS. Cell viability, cell apoptosis and serum hormone levels were assessed, the results of which showed that downregulation of miR-199a-5p contributed to the promotion of GC viability and inhibition of apoptosis, while simultaneously inducing the elevation of serum E2 level and reduction of serum AMH, PG, LH and FSH levels in the PCOS rat model. WT1 was identified as a target gene of miR-199a-5p by dual-luciferase reporter gene assay, and inhibition of miR-199a-5p resulted in the activation of WT1-mediated JAK/STAT3 pathway. The activated JAK/STAT3 pathway suppressed the development of PCOS by miR-199a-5p, indicating a mechanism by which miR-199a-5p could potentially prevent PCOS through the WT1-mediated JAK/STAT3 pathway.