ENTPD3 as a novel regulator of endometrial receptivity: suppressing EMT via the ATP-P2Y2 axis in patients with recurrent implantation failure.
BACKGROUND: Recurrent implantation failure (RIF) remains a major challenge in assisted reproductive technology and is primarily attributed to impaired endometrial receptivity. Despite its clinical significance, the precise mechanisms underlying RIF remain inadequately understood. METHODS: Single-cell RNA sequencing (scRNA-seq) was performed on endometrial samples from patients with RIF and healthy controls during the secretory phase using the 10X Genomics Chromium platform. The expression and localization of ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3) in the window of implantation (WOI) in the endometrium were examined using real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, and immunohistochemistry (IHC). A mouse model with ENTPD3 overexpression was utilized to assess embryo implantation in vivo, and an in vitro blastocyst adhesion assay was performed to evaluate endometrial receptivity. Additionally, Ishikawa cells were transduced with an ENTPD3 recombinant adenovirus to explore the underlying molecular mechanisms. RESULTS: ENTPD3 expression was significantly upregulated in the endometria of patients with RIF during the WOI, and its apical surface localization in endometrial epithelial cells was confirmed by single-cell data and IHC. Functional studies demonstrated that ENTPD3 overexpression impaired endometrial receptivity by suppressing epithelial-mesenchymal transition (EMT). In vivo, ENTPD3 overexpression markedly reduced endometrial receptivity and inhibited embryo implantation in mice. Consistently, in vitro assays revealed that ENTPD3 overexpression diminished blastocyst adhesion to endometrial epithelial cells. Mechanistically, ENTPD3 hydrolyzes ATP, thereby suppressing EMT via the P2Y2 signaling pathway and ultimately disrupting endometrial receptivity. CONCLUSIONS: Dysregulated ENTPD3 expression contributes to RIF pathogenesis by impairing endometrial receptivity through ATP hydrolysis-mediated suppression of EMT via P2Y2 signaling. These findings highlight ENTPD3 as a potential therapeutic target for improving implantation success in affected patients.