miRNA-29-3p targets PTEN to regulate follicular development through the PI3K/Akt/mTOR signaling pathway

Granulosa cells play a pivotal role in growth, development and ovulation of ovarian follicle. Simultaneously, autophagy and apoptosis processes are crucial determinants in the destiny of granulosa cells. Within this context, miR-29-3p, known to regulate a broad spectrum of biological processes and critical for tumor detection, prognosis, and treatment, is poised to clarify its roles in both autophagy and apoptosis. To enhance the understanding of the influence of miR-29-3p on follicular development, our study primarily delved into the realms autophagy and apoptosis. We employed a well-established chicken follicular atrophy model achieved through subcutaneous injection of tamoxifen (TMX) into hens. qPCR analysis revealed a significant decrease in the expression of miR-29-3p within the atrophic follicles. In our in vitro experiments with cultured chicken primary granulosa cells, miR-29-3p emerged as a novel microRNA capable of impeding autophagy and apoptosis when transfected with miR-29-3p mimics and inhibitors. Results from luciferase reporter assays corroborated that PTEN is a legitimate target of miR-29-3p. Unlike miR-29-3p, PTEN appeared to foster autophagy and apoptosis in chicken granulosa cells. Moreover, our findings uncovered that miR-29-3p facilitates the phosphorylation of Akt and mTOR proteins by targeting PTEN in chicken granulosa cells. In conclusion, the findings of this study suggest that miR-29-3p, through its targeting of PTEN via the Akt/mTOR signaling pathway, exerts inhibitory effects on autophagy and apoptosis. These effects may hold significant importance in the context of follicular development.