Mouse embryo models from chemically reprogrammed stem cells reach early organogenesis without transgenes

Two studies published in Cell and Cell Stem Cell describe mouse embryo models built from stem cells by chemical reprogramming, without transgenes. The work is summarized in a research highlight by Xiu Yu and Jichang Wang in the journal «Cell Regeneration». According to the highlight, the models replicate development up to early organogenesis, equivalent to embryonic day 8.5–8.75 biomedcentral.comCell Regenerationbiomedcentral.comOpen source ↗.

Embryo models derived from pluripotent stem cells (PSCs) are used to study mammalian embryonic development and to advance regenerative medicine. Earlier systems had limitations that the authors say these two studies overcome: complete embryo models are formed solely from stem cell types, with no exogenous genetic intervention.

Two chemical routes to an embryo model

In the first study, Li and colleagues used a purely chemical strategy to reprogram mouse embryonic stem cells (mESCs) into induced embryo founder cells (iEFCs). These cells are capable of forming complete embryo models, designated iEFC-EMs.

In the second study, Yilmaz and colleagues generated transgene-free post-gastrulation models, designated TF-SEMs. The starting material was naive mESCs and induced pluripotent stem cells (iPSCs), and the authors used a similar chemical cocktail biomedcentral.comCell Regenerationbiomedcentral.comOpen source ↗.

What the models reproduce, and where they stop

According to the authors, both systems faithfully recapitulate key developmental events of this post-gastrulation window: gastrulation, neural tube formation, cardiogenesis and somitogenesis. The highlight presents this as evidence that stem cell populations can self-organize into complete embryo models under chemical induction alone.

Yu and Wang describe the models as platforms for studying early mammalian development, modeling congenital defects and assessing embryotoxicity in laboratory studies. They also say the advances open the way to future applications in disease modeling and regenerative medicine.

The authors state the limits of current capabilities. Extending the developmental window beyond early organogenesis and establishing functional completeness remain technical requirements before these transgene-free systems can be used more broadly in basic and biomedical research biomedcentral.comCell Regenerationbiomedcentral.comOpen source ↗. All results described concern mouse cells and mouse embryo models grown in the laboratory.