Human stem cells self-pattern into post-implantation lineages.

Researchers have developed a system using human pluripotent stem cells that can self-organize into three-dimensional structures that mimic key events of early human post-implantation embryonic development. The system captures spontaneous differentiation and co-development of embryonic epiblast and extra-embryonic hypoblast-like lineages, establishes key signaling hubs with secreted modulators, and can undergo symmetry breaking-like events. Single-cell transcriptomics confirms differentiation into diverse cell states of the peri-gastrulating human embryo without establishing placental cell types, offering a reproducible, tractable, and scalable experimental platform to understand the basic cellular and molecular mechanisms that underlie human development.