Novel PGK1 determines SKP2-dependent AR stability and reprograms granular cell glucose metabolism facilitating ovulation dysfunction.

BACKGROUND: Disordered folliculogenesis is a core characteristic of polycystic ovary syndrome (PCOS) and androgen receptors (ARs) are closely associated with hyperandrogenism and abnormalities in folliculogenesis in PCOS. However, whether the new AR binding partner phosphoglycerate kinase 1 (PGK1) in granulosa cells (GCs) plays a key role in the pathogenesis of PCOS remains unclear.
METHODS: We identified the new AR binding partner PGK1 by co-IP (co-immunoprecipitation) in luteinized GCs, and reconfirmed by co-IP, co-localization and GST pull down assay, and checked PGK1 expression levels with qRT-PCR and western blotting. Pharmaceuticals rescue assays in mice, and metabolism assay, AR protein stability and RNA-seq of PGK1 targets in cells proved the function in PCOS.
FINDINGS: PGK1 and AR are highly expressed in PCOS luteinized GCs and PCOS-like mouse ovarian tissues. PGK1 regulated glucose metabolism and deteriorated PCOS-like mouse metabolic disorder, and paclitaxel rescued the phenotype of PCOS-like mice and reduced ovarian PGK1 and AR protein levels. PGK1 inhibited AR ubiquitination levels and increased AR stability in an E3 ligase SKP2-dependent manner. Additionally, PGK1 promoted AR nuclear translocation, and RNA-seq data showed that critical ovulation-related genes were regulated by the PGK1-AR axis.
INTERPRETATION: PGK1 regulated GCs metabolism and interacted with AR to regulate the expression of key ovulation genes, and also mediated cell proliferation and apoptosis, which resulted in the etiology of PCOS. This work highlights the pathogenic mechanism and represents a novel therapeutic target for PCOS. FUNDING: National Key Research and Development Program of China; National Natural Science Foundation of China grant.