The miR-424-3p/PIP5K1C axis regulates AKT phosphorylation and granulosa cell proliferation.

Abstract

MicroRNAs are important post-transcriptional regulators of intracellular signaling pathways that govern cell proliferation, apoptosis, and cell-cycle progression. However, whether miR-424-3p regulates PIP5K1C-associated AKT signaling in granulosa cells remains unclear. In this study, we investigated the molecular mechanism of miR-424-3p in goat granulosa cells (GCs). RT-qPCR analysis showed that miR-424-3p was more highly expressed in large follicles than in small follicles. Gain- and loss-of-function assays revealed that miR-424-3p inhibited GC proliferation, reduced the proportion of cells in S phase, and promoted apoptosis. Western blot analysis showed that miR-424-3p decreased the protein levels of CDK6 and CCND1. Dual-luciferase reporter assays and Western blotting identified BCL2 and PIP5K1C as direct targets of miR-424-3p. Functional rescue experiments further demonstrated that PIP5K1C overexpression promoted GC proliferation, increased CCND1 expression, and partially counteracted the inhibitory effects of miR-424-3p. Mechanistically, miR-424-3p suppressed AKT phosphorylation, whereas PIP5K1C enhanced AKT phosphorylation, suggesting that the miR-424-3p/PIP5K1C axis regulates GC fate through AKT signaling. These findings identify a previously unrecognized miR-424-3p/PIP5K1C/AKT regulatory axis that links post-transcriptional gene regulation to AKT-dependent granulosa cell proliferation and apoptosis.