The E3 Ubiquitin Ligase SYVN1 Plays an Antiapoptotic Role in Polycystic Ovary Syndrome by Regulating Mitochondrial Fission

Polycystic ovary syndrome (PCOS) is one of the most common hormonal disorders among premenopausal women. PCOS is accompanied by many other reproductive, endocrinal, and metabolic disorders thus amassing the difficulties encountered by the women affected. However, there is limited information on its molecular etiology. Synoviolin (SYVN1) is an E3 ubiquitin ligase that is thought to participate in the pathology of PCOS. However, the expression and function of SYVN1 in PCOS are unknown. In this study, we found that downregulation of SYVN1 expression was followed by increased apoptosis in the granulosa cells (GCs) of patients with PCOS. Subsequent in vitro experiments indicated that the overexpression of SYVN1 inhibited apoptosis and mitochondrial fission. Furthermore, using immunoprecipitation and western blotting, we identified that SYVN1 promoted the degradation of Drp1 via the proteasome-dependent pathway. Additionally, we generated a PCOS model in female Sprague Dawley rats and treated them with an SYVN1 inhibitor, LS-102. We observed that the inhibition of SYVN1 increased Drp1 levels and exacerbated the degeneration of GCs in the PCOS rat model. Finally, in vitro and in vivo experiments showed that SYVN1 inhibits apoptosis and mitochondrial fission by promoting Drp1 degradation in GCs. These results highlight the function of SYVN1 in PCOS and provide a potential target for the clinical treatment of PCOS.