SCGB2A1 deficiency impairs endometrial stromal cell decidualization by decreasing CDK3-mediated proliferation in patients with recurrent implantation failure

Recurrent implantation failure (RIF) presents a significant challenge in the field of assisted reproductive technology, primarily stemming from compromised decidualization that impacts endometrial receptivity. Despite ongoing research efforts, the comprehensive molecular regulatory mechanisms involved in RIF remain incompletely understood. This study revealed significantly reduced levels of secretoglobin, family 2A, member 1 (SCGB2A1) in both the mid-secretory endometrium and uterine fluid of RIF patients compared to control subjects. Besides, combined with RNA sequencing results, we demonstrated that the suppression of SCGB2A1 results in reduced cell proliferation and impaired decidualization by modulating CDK3 signaling during cell cycle transition in immortalized human endometrial stromal cells (T-HESCs) and primary HESCs. Furthermore, our findings indicated that inhibition of endometrial SCGB2A1 in a rat model hinders embryo implantation and disrupts decidualization. In conclusion, this study provides evidence that SCGB2A1 serves as a novel biomarker for endometrial receptivity and plays a crucial role in the regulation of human endometrial decidualization. The findings offer valuable insights into the pathogenesis of decidualization-related RIF and have the potential to enhance strategies for improving pregnancy outcomes.