Single-cell RNA sequencing reveals the effects of high-fat diet on oocyte and early embryo development in female mice.

BACKGROUND: Obesity is a global health issue with detrimental effects on various human organs, including the reproductive system. Observational human data and several lines of animal experimental data suggest that maternal obesity impairs ovarian function and early embryo development, but the precise pathogenesis remains unclear. METHODS: We established a high-fat diet (HFD)-induced obese female mouse model to assess systemic metabolism, ovarian morphology, and oocyte function in mice. For the first time, this study employed single-cell RNA sequencing to explore the altered transcriptomic landscape of preimplantation embryos at different stages in HFD-induced obese mice. Differential gene expression analysis, enrichment analysis and protein-protein interactions network analysis were performed. RESULTS: HFD-induced obese female mice exhibited impaired glucolipid metabolism and insulin resistance. The ovaries of HFD mice had a reduced total follicle number, an increased proportion of atretic follicles, and irregular granulosa cell arrangement. Furthermore, the maturation rate of embryonic development by in vitro fertilization of oocytes was significantly decreased in HFD mice. Additionally, the transcriptional landscapes of preimplantation embryos at different stages in mice induced by different diets were significantly distinguished. The maternal-to-zygotic transition was also affected by the failure to remove maternal RNAs and to turn off zygotic genome expression. CONCLUSIONS: HFD-induced obesity impaired ovarian morphology and oocyte function in female mice and further led to alterations in the transcriptional landscape of preimplantation embryos at different stages of HFD mice.

CISD2 regulates oxidative stress and mitophagy to maintain the balance of the follicular microenvironment in PCOS.

OBJECTIVES: To observe the CISD2 expression among PCOS patients and to explore its profound impact on the follicular microenvironment. Moreover, we want to elucidate the intricate mechanistic contribution of CISD2 to the onset and progression of PCOS. METHODS: Oxidase NOX2, mitophagy-related proteins, and CISD2 were detected by WB. The changes in mitochondrial structure and quantity were observed by transmission electron microscopy. Mitochondrial and lysosome colocalization was used to detect the changes of mitophagy. MDA kit, GSH and GSSG Assay kit and ROS probe were used to detect oxidative stress damage. RESULTS: We found that CISD2, mitophagy and oxidase in the GCs of PCOS patients were significantly increased. Testosterone stimulation leads to the increase of oxidase, mitophagy, and CISD2 in KGN cells. CISD2 inhibition promoted the increase of mitophagy, and the activation of mitochondria-lysosome binding, while alleviating the oxidative stress. CONCLUSIONS: Inhibition of CISD2 can improve the occurrence of oxidative stress by increasing the level of mitophagy, thus affecting the occurrence and development of PCOS diseases.

Correlation between ovarian follicular development and Hippo pathway in polycystic ovary syndrome.

BACKGROUND: For women of childbearing age, the biggest problem caused by polycystic ovary syndrome (PCOS) is infertility, which is mainly caused by anovulation, abnormal follicular development, proliferation of small antral follicles, and cystic follicles. The mechanism underlying its occurrence is not clear. The abnormal proliferation and development of follicles in PCOS patients is a complex process, which is affected by many factors. The objective of this study was to investigate the relationship between the Hippo pathway and follicular development in PCOS, and to further explore this relationship by using the YAP inhibitor verteporfin (VP). METHOD: 30 3-week-old BALB/C female rats were randomly divided into control group (n = 10), DHEA group (n = 10) and DHEA + VP group (n = 10). The morphology of ovary and the degree of follicular development were observed by HE staining, and the expression and location of AMH in ovarian follicles were observed by immunofluorescence. The ovarian reserve function index AMH, cell proliferation index PCNA and the ratio of Hippo pathway related proteins MST, LATS, YAP, P-YAP and P-YAP/YAP were detected by Western blot. RESULTS: After dividing 30 3-week-old female mice into control, dehydroepiandrosterone (DHEA; model of PCOS), and DHEA + VP groups, we found that the number of small follicles increased in the DHEA group compared to the control group. Additionally, in the DHEA group compared to the control group, anti-müllerian hormone (AMH; ovarian reserve index) increased, proliferating cell nuclear antigen (PCNA; cell proliferation index) decreased, and upstream (MST and LATS) and downstream (YAP and p-YAP) proteins in the Hippo pathway increased, though the p-YAP/YAP ratio decreased. VP ameliorated the increases in AMH, MST, LATS, YAP and p-YAP, but did not ameliorate the decrease in the p-YAP/YAP ratio. CONCLUSIONS: This study indicates that the increased small follicles in the ovaries and changes in ovarian reserve and cell proliferation may be closely related to Hippo pathway activation. This suggests that the Hippo pathway may be an important pathway affecting the proliferation and development of follicles and the occurrence of PCOS.