In other words, the team was able to reconstitute the three major tissues of the developing mouse embryo (heart, brain, and the basis for other organs) by starting with only ESCs (Cell Stem Cell, September 8, 2022). They did so by coaxing the ESCs with two extraembryonic lineages of the post-implantation embryo by transcription-factor-mediated induction.

The model captures developmental events from embryonic days 5.5 to 8.5, including gastrulation; formation of the anterior-posterior axis, brain, and a beating heart structure; and the development of extraembryonic tissues, including the yolk sac and chorion. When the researchers compared single-cell RNA sequencing from individual structures with time-matched natural embryos, they found "remarkably similar" transcriptional programs across the lineages. However, they also spotted when and where the model diverges from the natural embryo.

The research opens up avenues for generating organs in a cell culture that will eventually find application in transplant surgery or in regenerative medicine, according to the scientists.