Mfn2 regulates mitochondria-associated ER membranes to affect PCOS oocyte development

This study aimed to investigate the role of mitochondrial-related protein Mfn2 in polycystic ovary syndrome (PCOS) and its impact on oocyte development. The pathological features of PCOS model mice were confirmed by hematoxylin-eosin staining and immunohistochemistry. The expression of Mfn2 and mitochondrial-related proteins in PCOS oocytes and granulosa cells was detected by qRT-PCR and Western blot. Mitochondrial quantity was measured by Mito-Tracker staining, and the structure of mitochondria-associated ER membranes (MAMs) was observed by transmission electron microscopy. The results showed that Mfn2 was significantly downregulated in PCOS oocytes and granulosa cells, and its expression was inhibited in oocytes at different developmental stages. Moreover, the structure of MAMs was also disrupted. Downregulation of Mfn2 expression led to a reduction in mitochondrial quantity in oocytes and granulosa cells, as well as disruption of MAM structure, while overexpression of Mfn2 had the opposite effect. In conclusion, this study indicates that Mfn2 affects the development of PCOS oocytes by regulating MAMs and may be involved in maintaining the stability of MAM structure and function, thereby affecting mitochondrial quantity and function. These findings provide new insights into the pathogenesis and treatment of PCOS.