Exosomal miR-203a-3p Enhances Endometrial Receptivity by Upregulating E-Cadherin Expression Through the Direct Targeting of SNAI1 in Endometrial Epithelial Cells.

Purpose: Endometrial receptivity is a critical determinant of successful embryo implantation and is intricately linked to the pathophysiology of infertility. This study aimed to elucidate the role of exosomal miR-203a-3p in regulating endometrial receptivity, thereby providing insights into potential therapeutic strategies for infertility treatment.

Methods: Transcriptomic profiling of exosomes was performed to identify factors associated with endometrial receptivity. miR-203a-3p, exhibiting high expression levels in exosomes, was selected for further investigation. Human endometrial tissues from different menstrual phases and patient groups were analyzed for miR-203a-3p expression. Functional studies using miR-203a-3p mimics and engineered exosomes were conducted in non-receptive AN3-CA cells.

Results: During the secretory phase, miR-203a-3p expression was markedly higher in the endometria of fertile women than in those of infertile women. Overexpression of miR-203a-3p, which directly targeted Snail family transcriptional repressor (SNAI1), resulted in increased E-cadherin expression and enhanced spheroid attachment in non-receptive AN3-CA cells. Consistently, delivery of miR-203a-3p mimics via engineered exosomes increased E-cadherin expression by suppressing SNAI1 and enhanced spheroid adhesion in AN3-CA cells.

Conclusions: Our data highlight the importance of the miR-203a-3p/SNAI1/E-cadherin axis in governing endometrial receptivity. Exosome-mediated delivery of miR-203a-3p mimics may represent a promising therapeutic strategy for improving embryo implantation and treating infertility.