Human embryonic stem cell-derived immunity-and-matrix-regulatory cells promote endometrial repair and fertility restoration in IUA rats.

BACKGROUND: Intrauterine adhesion (IUA) refers to endometrial fibrosis resulting from endometrial injury and infection. In promoting the repair of the endometrium, mesenchymal stem cells therapy has shown great potential. However, adult-derived mesenchymal stem cells (MSCs) are associated with several challenges, including invasive manipulation, susceptibility to contamination, and low proliferative capacity. Immunity-and-matrix-regulatory cells (IMRCs) derived from human embryonic stem cells exhibit enhanced immunomodulatory and anti-fibrotic capabilities. Despite their success in treating lung injury and fibrosis, membranous nephropathy, and acute liver failure, their therapeutic potential in IUA remains undetermined. METHODS: TGF-β1-induced human endometrial stromal cells (HESCs) were utilized to construct the IUA cell model and were treated with IMRCs conditioned medium. Morphological changes in the cells were observed, and RT-qPCR and Western blot analyses were employed to detect the expression of relevant markers during the process of epithelial-mesenchymal transition (EMT) in vitro. The IUA rat model was established using the dual injury method and subsequently treated with intrauterine infusion of IMRCs. HE and Masson staining were used to assess endometrial damage, repair and the extent of fibrosis. Fertility assays were performed to compare the effectiveness of IMRCs and umbilical cord mesenchymal stem cells (UCMSCs) in improving endometrial function in IUA rats. Sequencing analysis of IMRCs-derived exosomes (Exos) was conducted to identify specific miRNAs and the pathways they target. RESULTS: TGF-β1 treatment induced HESCs to undergo fibrotic transformation and express fibrosis-related markers, while treatment with IMRCs conditioned medium inhibited TGF-β1-induced fibrosis. IUA rats were treated with intrauterine infusion of IMRCs. IMRCs facilitated the repair of damaged endometrium, restored the structure of the uterine cavity, and reduced collagen deposition. IMRCs reversed the process of endometrial EMT in rats with IUA, upregulated the expression of epithelial markers, and downregulated the expression of mesenchymal markers. IMRCs further exerted antifibrotic effects by reducing inflammatory responses. Fertility recovery in rats receiving intrauterine infusion of IMRCs was superior to that in rats receiving intrauterine infusion of UCMSCs. Specific miRNAs in Exos, including miR-27b-3p, miR-145-5p, and miR-16-5p, directly target Smad2, inhibit Smad2 phosphorylation, and modulate the TGF-β/Smad pathway. CONCLUSIONS: Our study demonstrated that IMRCs inhibited TGF-β1-induced fibrosis in HESCs, suppressed the EMT process ex vivo, reduced the inflammatory response, and reversed endometrial damage and fibrosis in IUA rats. IMRCs exerted their effects through the paracrine pathway, with specific miRNAs in Exos downregulating the TGF-β/Smad signaling pathway to inhibit uterine endometrial fibrosis. IMRCs provide a new direction for the treatment of IUA.