Human Trophectoderm Spheroid Derived from Human Embryonic Stem Cells.

The use of human embryos for studying the early implantation processes and trophoblast is restricted by ethical concerns. The development of models mimicking the peri-implantation embryos is critical for understanding the physiology of human embryos and many pathophysiological disorders including recurrent implantation failure and miscarriage. Three-dimensional (3D) models of trophoblastic spheroids have been successfully derived from human embryonic stem cells (hESC). Simultaneous activation of the BMP pathway and blockage of the Activin/Nodal pathway favor the differentiation of hESC into trophoblast. Here we describe a 3D trophectoderm differentiation protocol with the use of BAP (BMP4, A83-01, and PD173074) to generate hESC-derived trophectoderm spheroids (BAP-EB). BAP-EB is highly reproducible and exhibits morphological and transcriptomic similarities to human early blastocysts.