Integrative Single-Cell Analysis Reveals Iron Overload-Induced Senescence and Metabolic Reprogramming in Ovarian Endometriosis-Associated Infertility

Endometriosis, particularly ovarian endometriosis (OE), significantly impacts fertility by often leading to decreased oocyte quality and impaired ovarian function. Iron overload has been identified as a critical factor driving disease progression in endometriosis lesions. This study aims to investigate the effects of iron overload on follicular function in OE-associated infertility (OEI). Using single-cell sequencing technologies, we first identified oocyte dysfunction in OEI patients and established a single-cell atlas of iron overload in follicular fluid prior to ovulation in OEI patients. This atlas revealed dynamic changes in iron metabolism and identified iron-induced senescence phenotypes. We also examined the differentiation trajectories of granulosa cells and the relationship between macrophage M1/M2 phenotypes and iron metabolism. Additionally, we utilized Stereo-seq (spatiotemporal enhanced resolution omics-sequencing) to construct a spatial transcriptomic map of iron-overloaded mouse ovaries, uncovering various enriched senescence phenotypes. Finally, we extended our findings by exploring the dynamics of iron metabolism imbalance in aging human ovaries. Overall, these findings enhance our understanding of iron overload-related cellular interactions and molecular characteristics in ovarian pathology, providing new therapeutic targets for improving oocyte quality in OEI patients.