Mouse embryo models built from stem cells take shape in a dish

Abstract

Two groups have grown self-organizing models of mouse embryos from stem cells in vitro. The models mimic mid-gestation embryos, providing an unparalleled opportunity to study early embryonic development.

Keywords: Developmental biology; Stem cells.

Figure 1 ∣. Recapitulating mouse embryo development from stem cells in vitro.

a, Early in development, a mammalian embryo forms a structure, called a blastocyst, that contains three cell types: trophectoderm and primitive endoderm, which provide support for the developing embryo, and epiblast cells, which will give rise to the embryo. b, Two groups^, have now cultured trophectoderm-like and primitive-endoderm-like cells in vitro, in addition to mouse embryonic stem cells (mESCs), which have the capacity to give rise to embryonic cell types. The researchers then aggregated and mixed the cells in a culture well. The cells have innate principles of self-organization, which, together with an optimized culture medium, leads them to form a structure called an egg cylinder after three days. After five more days of culture and use of a rotating culture chamber, ‘embryoids’ develop, growing to resemble mid-gestation mouse embryos. (The embryoid shown is not an exact match for those described in ref. , but is adapted from Fig. 2 of ref. .)