Stem cells are unspecialized cells that can be manipulated to become mature cells with specialized functions.
“Our mouse embryonic model develops not only a brain, but a beating heart, and all the components that make up the body,” said Magdalena Zernicka-Goetz, lead author of the study and professor of mammalian development and stem cell biology at the university. . in Cambridge, England.
“It’s unbelievable that we’ve come this far. It’s been a dream of our community for years and the main focus of our work for a decade, and we’ve finally done it.”
Marianne Bronner, professor of biology at the California Institute of Technology (Caltech) in Pasadena, said the paper is an exciting advance and addresses the challenges scientists face when studying mammalian embryos in utero. challenge. Bronner was not involved in the study.
“These develop outside of the mother and thus can be easily visualized through key developmental stages that were previously inaccessible,” Bronner added.
Zernicka-Goetz said the researchers hope to move from mouse embryos to creating models of natural human pregnancy — many of which fail at an early stage.
She added that by looking at embryos in the lab rather than in the womb, scientists can better understand the process to understand why some pregnancies may fail and how to prevent it.
Study author Gianluca Amadei, a postdoctoral researcher at the University of Cambridge, said that currently, researchers can only track the development of synthetic mouse embryos for about eight days, but the process is improving and they have learned a lot.
“It reveals basic requirements that must be met in order for the embryo and its organs to have the correct structure,” Zernicka-Goetz said.
Benoit Bruneau, director of the Gladstone Institute of Cardiovascular Diseases and a senior fellow at Gladstone, said the current study doesn’t apply to humans and “requires a high degree of refinement to really work”. graduate School. Bruno was not involved in the study.
But the researchers see important uses for the future. Zernicka-Goetz said the process could be immediately used to test new drugs. But in the long run, as scientists move from mouse synthetic embryos to human embryo models, it could also help build synthetic organs for those in need of a transplant, Zernicka-Goetz added.
“I think this work is the first example of this kind of work,” said study author David Glover, Caltech research professor of biology and bioengineering.
How did they do that
In the womb, an embryo needs three types of stem cells to form: one that becomes the body tissue, another is the sac in which the embryo develops, and the third is the placenta that connects the parent and fetus, according to the study.
In Zernicka-Goetz’s lab, the researchers isolated three types of stem cells from embryos and cultured them in a slanted vessel to bring the cells together and facilitate crosstalk between them.
Day by day, they were able to see this group of cells form more and more complex structures, she said.
There are ethical and legal issues to consider before turning to human synthetic embryos, Zernicka-Goetz said. Because of the differences in complexity between mouse and human embryos, it could be decades before researchers can do something similar with human models, Bronner said.
But at the same time, the information from the mouse model could help “correct failing tissues and organs,” Zernicka-Goetz said.
The mystery of human life
The first few weeks after fertilization consist of these three different stem cells, which communicate with each other chemically and mechanically to allow the embryo to grow normally, the study said.
“A lot of pregnancies fail during this time period before most women[realize]they’re pregnant,” said Zenica-Goetz, who is also a professor of biology and bioengineering at Caltech. “This period of time is the foundation of everything after the pregnancy. If something goes wrong, the pregnancy will fail.”
But by this stage, the embryos produced by in vitro fertilization have already implanted in the parents, so scientists have limited visibility into what they are going through, Zernicka-Goetz said.
Glover said they were able to develop the basis of the brain — a first of its kind and “the holy grail of the field.”
“This period of human life is so mysterious, so being able to see how it happens in a petri dish – being able to get access to these individual stem cells, to understand why so many pregnancies fail and how we can prevent it from happening Happened – very special,” Zernicka-Goetz said in a press release. “We looked at the conversation that had to take place between the different types of stem cells at the time – we’ve shown how it happens and how it can go wrong.”