Ectopic endometrial stromal cell-derived extracellular vesicles encapsulating PKM2 inhibit autophagy inducing endometrial collagen I deposition in endometriosis

Endometriosis (EMs) is a common infertility-related disease in women of reproductive age. Impaired endometrial decidualization is one of the most important factors contributing to the embryo implantation failure EMs patients. However, the exact mechanism remains unclear. Previous studies have shown collagen I deposition in the eutopic endometrium of EMs patients, which may lead to impaired endometrial decidualization. The level of collagen I in eutopic endometrium of EMs was analyzed. We performed a proteomic analysis of ectopic endometrial stromal cell-derived extracellular vesicles (EMs-EVs) and extracellular vesicles derived from endometrial stromal cells in the endometrium of control patients (CTL-EVs). An endometrial transcriptional profiles of EMs patients and normal controls in the mid-secretory phase of menstrual cycle was compared. Endometrial stromal cells (ESCs) were stimulated with chloroquine or rapamycin to evaluate the association between autophagy and collagen I. The expression of PKM2 in EMs-EVs and serum extracellular vesicles from EMs patients were examined by western blotting. PKM2 was overexpressed or knockdown in ESCs to investigate the level of autophagy and collagen I. ESCs were treated with ectopic ESC-derived extracellular vesicles with highly expressed PKM2 protein, and the potential molecular mechanisms were further confirmed through western blotting and immunohistochemical analysis. We found that endometrial collagen I expression during the mid-secretory phase was increased in the EMs group. We demonstrated that autophagy is defective in eutopic endometrial stromal cells (ESCs) of EMs patients. In ESCs, pharmacological inhibition of autophagy by chloroquine (CQ) promoted collagen I deposition. Ectopic endometrial stromal cell-derived extracellular vesicles (EMs-EVs) inhibited autophagy of ESCs and promoted collagen I deposition in vivo and in vitro. Mechanistically, EMs-EVs encapsulating PKM2 impair eutopic endometrial autophagy via Akt/mTOR signaling pathway. Together, we demonstrated that EMs-EVs encapsulating PKM2 impaired endometrial autophagy inducing collagen I deposition in EMs, which provided a potential target for therapeutic implications.