MicroRNA-30a-3p regulates epithelial-mesenchymal transition to affect embryo implantation by targeting Snai2

Objective: To study the potential role of miR-30a-3p in embryo implantation and explore underlying mechanisms. Methods: We first established normal pregnancy, pseudopregnancy, delayed implantation, and artificial decidualization mouse models. Next, we detected miR-30a-3p expression profiles of these models with real-time reverse transcription PCR(qRT-PCR), then predicted potential target genes through a dual-luciferase assay. Immunofluorescence-fluorescence in situ hybridization co-located miR-30a-3p and target genes. We then examined the effect of miR-30a-3p on embryo implantation in vivo and in vitro. Wound healing and transwell assays were employed to explore possible miR30a-3p effects on epithelial-mesenchymal transition (EMT), before molecules related to the latter process were examined with qRT-PCR. Results: MiR-30a-3p expression decreased significantly on embryo implantation day, compared with the peri-implantation period (P < 0.05). Identified target gene Snai2 expression increased significantly during implantation (P < 0.05). In vivo and in vitro analysis showed that up-regulation of miR-30a-3p by agomir and mimics resulted in decreased implantation sites and embryo implantation rate. Transfection of miR-30a-3p mimics to HEC-1-b cells decreased expression of Snai2 and mesenchymal markers (Vimentin and N-cadherin). Furthermore, wound healing area decreased, as did migration and invasion capacity. Conclusion: MiR-30a-3p is down-regulated in the embryo implantation period and might have some effect on embryo implantation by acting as a suppressor of EMT through targeting Snai2. Summary Sentence MiR-30a-3p is down-regulated on the embryo implantation day and suppresses the EMT through targeting Snai2, and up-regulation of miR-30a-3p weakens the capacity of migration and invasion.