miR-24-3p promotes proliferation and inhibits apoptosis of porcine granulosa cells by targeting P27

Ovarian follicle development is associated with the physiological functions of granulosa cells (GCs), including proliferation and apoptosis. The level of miR-24-3p in ovarian tissue of high-yielding Yorkshire×Landrace sows was significantly higher than that of low-yielding sows. However, the functions of miR-24-3p on GCs are unclear. In this study, using flow cytometry, 5-ethynyl-2´-de-oxyuridine (EdU) staining, and cell count, we showed that miR-24-3p promoted the proliferation of GCs increasing the proportion of cells in the S phase and upregulating the expression of cell cycle genes, moreover, miR-24-3p inhibited GC apoptosis. Mechanistically, on-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target gene of miR-24-3p in proliferation and apoptosis is cyclin-dependent kinase inhibitor 1B (P27/CDKN1B). Furthermore, the effect of miR-24-3p on GC proliferation and apoptosis was attenuated by P27 overexpression. These findings suggest that miR-24-3p regulates the physiological functions of GCs.