According to the researchers, the findings, described in a paper published in Nature today, could help scientists learn more about how human embryos develop and provide insights into disease, as well as providing an alternative to animals for testing.
“I think it’s a big breakthrough,” says Leonardo Beccari of the Severo Ochoa Molecular Biology Center in Madrid, who was not involved in the research.
Studying how mouse stem cells interact at this point in development could also provide valuable insight into why human pregnancies fail during the early stages and how to prevent this from happening.
“This is really the first demonstration of the forebrain in any model of embryonic development, and this has been a holy grail for the field,” says David Glover, research professor of biology and biological engineering at Caltech, who co-authored the report. .
Stem cells can become specialized cells, such as muscle, brain, or blood cells. The synthetic embryos were made up of three types of mouse cells: embryonic stem cells, which form the body; trophoblast stem cells, which develop in the placenta; and the extraembryonic endoderm stem cells, which help form the egg sac.
The embryos were developed in an artificial incubator created by Jacob Hanna of Israel’s Weizmann Institute, who recently kept realistic-looking mouse embryos growing in a mechanical womb for several days until they developed beating hearts, blood flowing and cranial folds. Hanna is also a co-author of the new study.
By mimicking the natural processes of how a mouse embryo would form inside a womb, the researchers were able to guide the cells to interact with each other, causing them to self-organize into structures that progressed through the stages of development to the point where they beat. hearts and foundations for the whole brain.
The team also deleted a gene called Pax6, which is essential for the formation of the central nervous system and the development of the brain and eyes, to test how the model embryos would react. The synthetic models showed the same known defects in brain development as a natural animal carrying the mutation. Next, researchers are interested in knocking out genes with unknown roles in brain development, which could shed light on the cause of some defects.