Oocyte-derived growth differentiation factor 9 suppresses the expression of CYP17A1 and androgen production in human theca cells

Abstract

ObjectiveTo investigate the direct effect of growth differentiation factor 9 (GDF9) on androgen production in human theca cells. DesignExperimental study SettingTertiary hospital-based research laboratory Patient(s)Women underwent IVF/intracytoplasmic sperm injection (ICSI) at our clinic were included in this study. Intervention(s)Primary cultured human theca cells from women undergoing IVF/ICSI treatment were treated with GDF9, Activin receptor-like kinase 5 (ALK5) inhibitor, and SMAD4 agonist. Main Outcome Measure(s)The expression of androgen synthesis-related gene StAR, CYP17A1, and LHCGR, levels of androstenedione and testosterone, phosphorylation of SMAD2/3 and the interaction between bone morphogenetic protein receptor II (BMPRII) and ALK5 were evaluated by RT-qPCR, Western blot, enzyme-linked immunosorbent assays, and co-immunoprecipitation assays respectively. ResultsGDF9 decreased StAR, CYP17A1, and LHCGR expression levels in human theca cells, which was prevented by the treatment with the ALK5 inhibitor, and suppressed production of androgen in human theca cells. GDF9 increased SMAD2/3 phosphorylation, and the ALK5 inhibitor also suppressed this effect. BMPRII and ALK5 bound to each other following GDF9 stimulation. The SMAD4 agonist kartogenin also decreased mRNA levels of StAR and CYP17A1, and protein levels of StAR in human theca cells. ConclusionGDF9 can activate the BMPRII-ALK5-SMAD2/3 signaling pathway, suppress CYP17A1 expression and androgen production in human theca cells.