Endometriosis (EMs) occurs in approximately 50% of women with infertility. The main causes of EMs-related infertility are follicle dysplasia and reduced oocyte quality. Iron overload occurs in ovarian follicular fluid (FF) of patients with EMs, and this condition is associated with oocyte maturation disorder. However, the underlying molecular mechanism remains largely unknown. In the present study, we identified the mechanism underlying ferroptosis in ovarian granulosa cells and oocyte maturation failure in EMs based on a retrospective review of in vitro fertilization/intracytoplasmic sperm injection-frozen embryo transfer outcomes in infertile patients with EMs. Mouse granulosa cells were treated with EMs-related infertile patients' follicular fluid (EMFF) in vitro. Western blot analysis, quantitative polymerase chain reaction, fluorescence staining, and transmission electron microscopy were used to assess granulosa cells ferroptosis. The effects of exosomes were examined by nanoparticle tracking analysis, RNA-seq, and Western blot analysis. Finally, the therapeutic values of vitamin E and iron chelator (deferoxamine mesylate) in vivo were evaluated in an EMs-related infertility model. Patients with ovarian EMs experienced poorer oocyte fertility than patients with non-ovarian EMs. We observed that EMFF with iron overload-induced granulosa cell ferroptosis in vitro and in vivo. Mechanically, nuclear receptor coactivator four-dependent ferritinophagy was involved in this process. Notably, granulosa cells undergoing ferroptosis further suppressed oocyte maturation by releasing exosomes from granulosa cells. In therapeutic studies, vitamin E and iron chelators effectively alleviated EMs-related infertility models. Our study indicates a novel mechanism through which EMFF with iron overload induces ferroptosis of granulosa cells and oocyte dysmaturity in EMs-related infertility, providing a potential therapeutic strategy for EMs-related infertility.

Objective: This study aimed to explore the relationship between the fecal metabolites and gut microbiota in obese patients with PCOS and provide a new strategy to elucidate the pathological mechanism of obesity and PCOS. Methods: The fecal samples of obese patients with PCOS (n = 18) and obese women without PCOS (n = 15) were analyzed by 16S rRNA gene sequencing and untargeted metabolomics. The peripheral venous blood of all subjects was collected to detect serum sex hormones. The association among fecal metabolites, gut microbiota, and serum sex hormones was analyzed with the R language. Results: A total of 122 named differential fecal metabolites and 18 enrichment KEGG pathways were obtained between the groups. Seven fecal metabolites can be used as characteristic metabolites, including DHEA sulfate. The richness and diversity of gut microbiota in the obese PCOS group were lower than those in the control group. Lachnoclostridium, Fusobacterium, Coprococcus_2, and Tyzzerela 4 were the characteristic genera of the obese patients with PCOS. Serum T level significantly and positively correlated with the abundance of fecal DHEA sulfate (p < 0.05), and serum DHEAS level significantly and negatively correlated with the abundance of fecal teasterone (p < 0.05). Conclusion: Specific fecal metabolites may be used as characteristic metabolites for obese patients with PCOS. The closely relationship among gut microbiota, fecal metabolites, and serum sex hormones may play a role in the related changes caused by hyperandrogenemia.

Polycystic ovary syndrome (PCOS) is a chronic endocrine and metabolic disease. Gut microbiota is closely related to many chronic diseases. In this study, we conducted a cross-sectional study and recruited 30 obese (OG) and 30 non-obese (NG) women with PCOS, 30 healthy women (NC) and 11 healthy but obese women (OC) as controls to investigate the characteristic gut microbiota and its metabolic functions in obese and non-obese patients with PCOS. The blood and non-menstrual faecal samples of all the participants were collected and analysed. As a result, the Hirsutism score, LH/FSH and serum T level in NG and OG both increased significantly compared with their controls (P < 0.05). High-throughput 16S rRNA gene sequencing revealed that the abundance and diversity of the gut microbiota changed in patients with PCOS. The linear discriminant analysis (LDA) indicated that Lactococcus was the characteristic gut microbiota in NG, while Coprococcus_2 in OG. Correlation heatmap analysis revealed that the sex hormones and insulin levels in human serum were closely related to the changes in the gut microbiota of NG and OG. Functional prediction analysis demonstrated that the citrate cycle pathway enriched both in NG and OG, and other 12 gut bacterial metabolic pathways enriched in NG. This study highlighted significant differences in the gut microbiota and predictive functions of obese and non-obese women with PCOS, thereby providing insights into the role and function of the gut microbiota that may contribute to the occurrence and development of PCOS in obese and non-obese women.