FOXO1 Targets LHX8 to Promote Granulosa Cell Apoptosis

Abstract

Women with diminished ovarian reserve (DOR) have reduced fertility, but the mechanisms regulating ovarian function remain unclear. This study aims to explore the mechanism by which FOXO1 regulates ovarian granulosa cell function. The ovarian granulosa cell line KGN was cultured and transfected with FOXO1 and LHX8 vectors. Cell proliferation and apoptosis were assessed using CCK-8 and flow cytometry, respectively. mtROS content was determined by immunofluorescence. ATP was detected using an assay kit. E2 was detected by ELISA. ChIP was used to detect the binding of FOXO1 to the LHX8 promoter. Luciferase reporter genes were used to analyze the regulation of FOXO1 on LHX8 promoter activity. RT-qPCR was performed to measure the expression of FOXO1 mRNA, LHX8 mRNA, ND1, and β-globin. Western blotting was used to detect FOXO1, LHX8, and aromatase proteins.FOXO1 knockdown or LHX8 overexpression promoted proliferation, inhibited apoptosis, reduced mitochondrial ROS, and increased ATP, mtDNA, E2, and aromatase levels in KGN cells. FOXO1 overexpression or LHX8 knockdown produced the opposite regulatory effects. FOXO1 bound to the LHX8 promoter and reduced its activity. LHX8 overexpression eliminated FOXO1-induced KGN cell damage. In conclusion, FOXO1 reduces viability and promotes apoptosis in granulosa cells by inhibiting LHX8 transcription to induce mitochondrial dysfunction, which may contribute to DOR.