Hypoblast from human pluripotent stem cells regulates epiblast development

TLDR

Human embryology differs from mice, and ethical constraints limit post‑implantation studies, prompting the development of in‑vitro self‑organizing models using human stem cells. The study aims to generate authentic hypoblast cells from naive human pluripotent stem cells. The authors employ both genetic and non‑genetic strategies to derive naive hPSC‑derived hypoblast‑like cells (nHyCs). nHyCs spontaneously co‑assemble with naive hPSCs into bilaminar structures that, when combined with trophectoderm analogues, double formation efficiency and support epiblast development driven by IL‑6, recapitulating anterior‑posterior patterning and pregastrula‑stage cell emergence that can be modulated by DKK1/OTX2 manipulation.

Abstract

Abstract Recently, several studies using cultures of human embryos together with single-cell RNA-seq analyses have revealed differences between humans and mice, necessitating the study of human embryos 1–8 . Despite the importance of human embryology, ethical and legal restrictions have limited post-implantation-stage studies. Thus, recent efforts have focused on developing in vitro self-organizing models using human stem cells 9–17 . Here, we report genetic and non-genetic approaches to generate authentic hypoblast cells (naive hPSC-derived hypoblast-like cells (nHyCs))—known to give rise to one of the two extraembryonic tissues essential for embryonic development—from naive human pluripotent stem cells (hPSCs). Our nHyCs spontaneously assemble with naive hPSCs to form a three-dimensional bilaminar structure (bilaminoids) with a pro-amniotic-like cavity. In the presence of additional naive hPSC-derived analogues of the second extraembryonic tissue, the trophectoderm, the efficiency of bilaminoid formation increases from 20% to 40%, and the epiblast within the bilaminoids continues to develop in response to trophectoderm-secreted IL-6. Furthermore, we show that bilaminoids robustly recapitulate the patterning of the anterior–posterior axis and the formation of cells reflecting the pregastrula stage, the emergence of which can be shaped by genetically manipulating the DKK1/OTX2 hypoblast-like domain. We have therefore successfully modelled and identified the mechanisms by which the two extraembryonic tissues efficiently guide the stage-specific growth and progression of the epiblast as it establishes the post-implantation landmarks of human embryogenesis.