Context: Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder accompanied by chronic low-grade inflammation, but the molecular mechanism remains unclear.
Objective: We investigated the action of WNT5a in the development of chronic inflammation in PCOS and the related molecular signaling pathways.
Design and setting: This was a prospective study conducted at the Division of Reproduction Center, Peking University Third Hospital.
Patients: A total of 35 PCOS patients and 87 control women who reported to the clinic for the in vitro procedure and the cause of marital infertility was male azoospermia were included.
Main outcome measures: Mural granulosa cells (GCs) of 35 PCOS patients and 37 controls were collected during oocyte retrieval and gene expression was analyzed. The human KGN cells and mural GCs from 50 control subjects (six to eight samples were pooled together for each experiment) were cultured in vitro. The regulation of inflammation and oxidative stress was confirmed by quantitative PCR, flow-cytometric assay, and dual-luciferase reporter assay after inflammatory stimuli or WNT5a overexpression. Relevant signaling pathways were identified using specific inhibitors.
Results: Our data demonstrate significantly elevated WNT5a expression in the mural GCs of PCOS patients compared with the controls. Lipopolysaccharide stimulation increased WNT5a expression in KGN cells and mural GCs, and BAY-117082 and pyrrolidinedithiocarbamic acid [nuclear factor-κB (NF-κB) inhibitor] treatments suppressed WNT5a mRNA below the control level. WNT5a overexpression also enhanced the expression of inflammation-related genes and increased intracellular reactive oxygen species, whereas both BAY-117082 and LY-294002 (phosphatidylinositol 3-kinase inhibitor) significantly inhibited WNT5a-induced inflammation and oxidative stress.
Conclusions: WNT5a acts as a proinflammatory factor in human ovarian GCs. The up-regulated expression of WNT5a in PCOS increases inflammation and oxidative stress predominantly via the phosphatidylinositol 3-kinase/AKT/NF-κB signaling pathway. The proinflammatory cytokines induced might further enhance WNT5a expression via NF-κB-dependent regulation, indicating a novel regulatory system for chronic inflammation in PCOS.