miR-130a-5p regulates steroid hormone synthesis in porcine ovarian granulosa cells by targeting APOE and modulating cholesterol metabolism.

The function of ovarian granulosa cells is central to follicular development and hormone production. To identify miRNAs associated with estrous status, we performed miRNA sequencing on ovaries from gilts that displayed estrus (ES) or remained non‑estrus (NES). miR‑130a‑5p was significantly upregulated in NES ovarian follicular tissues. In primary porcine granulosa cells, miR-130a-5p overexpression reduced estradiol(E2) secretion and decreased the abundance of key steroidogenic proteins, whereas miR-130a-5p inhibition increased E2 and progesterone(P4) secretion. miR-130a-5p also altered lipid droplet accumulation and the abundance of cholesterol metabolism-related proteins, including HMGCR and LDLR. Integrative target prediction combined with transcriptomic filtering identified apolipoprotein E (APOE) as a candidate target. A dual‑luciferase reporter assay confirmed direct binding of miR‑130a‑5p to the APOE 3'UTR. Functionally, APOE overexpression enhanced E₂ and P₄ secretion and increased lipid accumulation and HMGCR/LDLR expression, whereas APOE knockdown exerted opposite effects. Moreover, APOE overexpression attenuated the inhibitory effects of miR-130a-5p on steroid hormone production and steroidogenesis-related gene expression. Together, these findings identify a miR-130a-5p/APOE axis that links cholesterol metabolism-related processes to steroid hormone synthesis in porcine granulosa cells and provides a candidate pathway for further investigation of endocrine regulation in gilts.