Onecut2, negatively regulated by methyltransferase METTL3, inhibits polycystic ovary syndrome by transcriptionally modulating SIRT3 expression.

Polycystic ovary syndrome (PCOS) is characterized by a constellation of symptoms, including menstrual cycle irregularities, hyperandrogenism, and polycystic ovarian morphology. Despite extensive research efforts, a thorough understanding of the underlying pathophysiology and effective treatment options for PCOS remain elusive. In this study, ovarian tissues from dehydroepiandrosterone (DHEA)-induced PCOS mice and control mice underwent mRNA sequencing. Through a comprehensive bioinformatics analysis, we systematically examined the sequencing data, and one cut homeobox 2 (Onecut2), a significantly downregulated gene in PCOS mice, was identified and selected as the primary research target. Our findings determined that the overexpression of Onecut2 efficiently alleviated pathological changes and reduced mitochondrial dysfunction in DHEA-induced PCOS mice. Additionally, Onecut2 was found to be expressed at a low level in human ovarian granulosa KGN cells treated with dihydrotestosterone (DHT). Gain-of-function and loss-of-function experiments uncovered that Onecut2 played a role in inhibiting apoptosis and mitochondrial damage in DHT-treated KGN cells. Dual-luciferase reporter assays demonstrated that Onecut2 overexpression activated the transcriptional activity of the sirtuin 3 (SIRT3) promoter, thereby controlling the function of granulosa cells. Mechanistic investigation revealed that the mRNA stability of Onecut2 was regulated by methyltransferase-like 3 (METTL3) via m6A modification. Collectively, this study demonstrates that Onecut2 exerts an inhibitory role in PCOS progression by transcriptionally regulating SIRT3 expression and that this regulation is influenced by METTL3-mediated m6A methylation.