Researchers publish how-to guide for mouse-human chimeric embryo

9 Jul 2021

Human stem cells are injected into a mouse embryo. Image: Aimee Stablewski and Dawn Barnas/Gene Targeting and Transgenic Resource, Roswell Park Comprehensive Cancer Center

In a bid to ‘fundamentally change how we treat many human diseases’, a new paper details how to grow human cells in a mouse embryo.

In a research paper published last week (2 July), researchers from the University of Buffalo gave a step-by-step guide to their biomedical research techniques involving mouse-human chimeras.

“This paper will enable many scientists to use this new platform to study the human disease of their interest,” said Dr Jian Feng, professor in the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo and senior author of the paper.

“These mice contain critical human cells, tissues or even organs so that they more accurately reflect the human condition.”

This isn’t the first time Feng has made headlines for his work. Published in Science Advances back in May 2020, Feng and colleagues caused a splash when they described their biomedical research concerning mouse-human chimeras.

This time, however, the researchers aren’t showing what they did, but describing how to do it.

In Greek mythology, a chimera was a fearsome, fire-breathing creature with aspects of a lion, goat and snake. Modern medical chimeras give a nod to antiquity and chimera now refers to organisms with cells from two or more sets of DNA.

In this case, the researcher chose that of a mouse and a human. The process involves human primed stem cells co-developing with the inner cell mass inside of a mouse embryo.

Creating chimeras containing 4pc human cells, they have taken a step forward for medical research that has struggled to keep these cells alive because of compatibility issues.

The ability to mass-make mature human cells in a living organism is a central part of the predicted therapeutic potentials of stem cells.

This could involve creating human-like models using chimeras for research, or the generation of human tissue in animals.

So impressed was the scientific community after the publication of this research, the authors were invited to share their methods in Nature Protocols and facilitate the research of others.

“With our method, the human cells are made along with the mouse during the development of the mouse embryo. There would be better matching and no rejections, because there are ways for the human cells to be made where there is no competition from their mouse counterparts,” Feng explained.

“If naive human pluripotent stem cells are able to generate significant amounts of mature human cells in other larger species, it could be possible to make human tissues or even human organs in chimeric animals.”

Research on chimeras has faced criticism in the past, arising from bioethical concerns. Many researchers fall on either side of the debate.

Feng highlighted the critical problem of organ shortages, however, and argued: “Ultimately, a better understanding of how human cells develop and grow in chimeras may enable the generation of human cells, tissues and organs in a completely artificial system and fundamentally change how we treat many human diseases.

“Research using chimeras is a bridge that must be crossed to reach that possibility.”

Sam Cox was a journalist at Silicon Republic covering sci-tech news