Placental trophoblast cell-derived exosomal microRNA-1290 promotes the interaction between endometrium and embryo by targeting LHX6

Communication between the maternal uterus and the embryo is vital for a successful pregnancy. Exosomes, subtypes of extracellular vesicles comprising many bioactive factors, regulate the early stages of pregnancy, specifically during embryo implantation. Nevertheless, the mechanism by which exosomal microRNAs (miRNAs) derived from placental trophoblasts regulate embryo implantation remains elusive. We isolated and identified exosomes derived from placental trophoblast cells (HTR8/SVneo). Subsequently, we evaluated the loading miRNA in exosomes by small RNA sequencing. Consequently, we showed that trophoblast cell-derived exosomes could transfer to endometrial epithelial cells. Besides, these exosomes promoted the epithelial-mesenchymal transition (EMT) as well as migration of endometrial cells and were implicated in the regulation of inflammation. Further, the specific miRNAs were screened in exosomes, and as a result, miRNA (miR)-1290 was enriched specifically in exosomes. miR-1290 promoted the expression of inflammatory factors (interleukin [IL]-6 and IL-8) and migration of endometrial epithelial cells. In addition, exosomal miR-1290 promoted angiogenesis in vitro. More importantly, by targeting LHX6, trophoblast HTR8/SVneo cell-derived exosomal miR-1290 promoted the EMT process of endometrial epithelial cell HEC-1-A. Altogether, our findings provide novel insights into the mechanism of trophoblast cell-derived exosomes during embryo implantation.