Notch2 improves granulosa cell functions in premature ovarian failure by activating the Wnt2/β-catenin pathway.

BACKGROUND: Notch2 and Wnt2/β-catenin pathway improve granulosa cell (GC) functions, and there are interactions between Notch and Wnt/β-catenin in some cells. We aimed to investigate whether Notch2 improves GC functions in premature ovarian failure (POF) by activating the Wnt2/β-catenin pathway. METHODS: Notch2 expression was interfered in mice or KGN cells, then, mice were treated with cyclophosphamide and busulfan intraperitoneally, and KGN cells were exposed to cyclophosphamide to establish POF models. In vivo, the number of follicles at different stages was counted, and interactions between Notch2 and Wnt2 were detected. In vitro, cell viability and cycle were measured. Additionally, hormone levels, oxidative stress (OS) degrees, cell apoptosis, Notch2 and Wnt2/β-catenin pathway-related genes were detected in vivo and in vitro. Finally, Wnt/β-catenin pathway inhibitor (IWR-1), agonist (SKL2001) and β-catenin knockdown were used. RESULTS: Notch2 overexpression not only improved hormone levels, follicular development, OS degree and ovarian cell apoptosis, but also activated Wnt2/β-catenin pathway for POF mice. Moreover, Notch2 interacted with Wnt2 in POF mice. In vitro, Notch2 knockdown decreased cell viability, disrupted cell cycle, increased cell apoptosis, worsened hormone levels, promoted OS degree and inhibited Wnt2/β-catenin pathway for POF. Importantly, the protective effects of Notch2 overexpression and the worsening impacts of Notch2 knockdown on POF were reversed by IWR-1 and SKL2001. β-Catenin knockdown further impaired GC functions in POF models that underwent Notch2 and β-catenin knockdown. CONCLUSION: Notch2 may improve GC functions in POF by activating the Wnt2/β-catenin pathway, suggesting that the Notch2-mediated Wnt2/β-catenin pathway is a novel therapeutic target for POF.