Proteome reprogramming of endometrial epithelial cells by human trophectodermal small extracellular vesicles reveals key insights into embryo implantation.

Embryo implantation into the receptive endometrium is critical in pregnancy establishment, initially requiring reciprocal signalling between outer layer of the blastocyst (trophectoderm cells) and endometrial epithelium; however, factors regulating this crosstalk remain poorly understood. Although endometrial extracellular vesicles (EVs) are known to signal to the embryo during implantation, the role of embryo-derived EVs remains largely unknown. Here, we provide a comprehensive proteomic characterisation of a major class of EVs, termed small EVs (sEVs), released by human trophectoderm cells (Tsc-sEVs) and their capacity to reprogram protein landscape of endometrial epithelium in vitro.