Trophectoderm-like cells from EPS cells enable generating EPS cell-derived post-implantation embryoids that complete gastrulation.

Mouse extended pluripotent stem (EPS) cells have demonstrated significant potential for generating embryo models in vitro. However, their limited capacity for extraembryonic trophoblast development has hindered their use in constructing whole embryo models, particularly post-implantation embryoids. Here, we establish a stepwise induction protocol to generate trophectoderm-like cells from mouse EPS cells. These cells retain trophectoderm-specific transcriptomic features and can differentiate into trophoblast lineages in vivo. Moreover, combining these trophectoderm-like cells with EPS cell-derived primitive endoderm/epiblast bilineage structures enabled the robust generation of post-implantation embryoids in a transgene-free manner. EPS-derived embryoids recapitulate key developmental events of post-implantation mouse embryos, including the formation of the pro-amniotic cavity, anterior-posterior axis, primitive streak, gastrulation, and complex extraembryonic tissues. Notably, single-cell transcriptomic analysis revealed a high degree of transcriptional similarity between EPS-derived embryoids at day 6 and natural E7.5 mouse embryos. Our study presents a novel platform for modeling post-implantation mouse embryogenesis in vitro.