Vigilin interacts with ER-β to protect against palmitic acid-induced granulosa cells apoptosis via inhibiting calcineurin-mediated Drp1 signaling pathway

Background: Hypercholesterolemia is one of the causes of female infertility, and as a common fatty acid in follicular fluid, palmitic acid (PA) level plays a vital role in granule cell which is closely related to the developmental potential of follicle. Methods: The ovarian granulosa cell-like human granulosa (KGN) cell line and the immortalized normal ovarian surface epithelial cell line (IOSE80) were used to verify the effect of PA on cell viability and apoptosis by MTT and flow cytometry assay, respectively. Then mitochondria damage was confirmed by mitochondrial membrane potential, mitochondrial ROS detection assay and western blot in KGN cells. Thorough luciferase reporter assay and RIP-qPCR, the relationship between vigilin and ER-5 was investigated. Results: In our study, PA induced mitochondrial damage-mediated cell apoptosis of KGN cells was dose-dependently, while PA shown no effects on in IOSE80 cells. Then the role of calcineurin (CnA)-mediated Drp1 signaling pathway on KGN cells was confirmed by treating with Mdivi-1 or FK506T. In addition, the changed level of vigilin and ER-beta was observed in cell apoptosis of KGN cells induced by PA. By transfecting vigilin vector or ER-beta vector into KGN cells, respectively, vigilin and ER-beta were demonstrated to regulate the apoptosis of KGN cells. And vigilin was a binding protein of ER-beta mRNA. Conclusion: Vigilin could interact with ER-beta mRNA to promote ER-beta expression. And Vigilin/ ER-beta relieve the mitochondrial damage and cell apoptosis induced by PA through regulating CnA-mediated Drp1 signaling pathway, which revealed the mechanism and strategy of hypercholesterolemia in female infertility.