Self-organization of stem cells into embryos: A window on early mammalian development

TLDR

Embryonic development is orchestrated by complex regulatory mechanisms across scales, yet in vivo mammalian studies after implantation are hampered by the embryo’s small size and inaccessibility. The authors review how stem‑cell embryo models can dissect developmental complexity and illustrate the principles of self‑organization that drive embryogenesis. They manipulate geometry, physical cues, and chemical priming to induce patterning, and by adding extraembryonic lineage cells they create autonomous 3‑D models that recapitulate pre‑ and post‑implantation mouse embryo features, including gastrulation. The resulting 3‑D models autonomously recapitulate pre‑ and post‑implantation mouse embryo features, including gastrulation.

Abstract

Embryonic development is orchestrated by robust and complex regulatory mechanisms acting at different scales of organization. In vivo studies are particularly challenging for mammals after implantation, owing to the small size and inaccessibility of the embryo. The generation of stem cell models of the embryo represents a powerful system with which to dissect this complexity. Control of geometry, modulation of the physical environment, and priming with chemical signals reveal the intrinsic capacity of embryonic stem cells to make patterns. Adding the stem cells for the extraembryonic lineages generates three-dimensional models that are more autonomous from the environment and recapitulate many features of the pre- and postimplantation mouse embryo, including gastrulation. Here, we review the principles of self-organization and how they set cells in motion to create an embryo.