By manipulating a specific gene in a mouse blastocyst — the structure that develops from a fertilized egg but is not yet an actual embryo — scientists with the University of Florida's McKnight Brain Institute and the Harvard Stem Cell Institute caused cells destined to build an embryo to instead change direction and build the cell mass that leads to the placenta.
Writing in today's (Monday, June 9) online edition of Nature Genetics, the scientists reveal a cellular signaling mechanism in place at the earliest developmental stage.
Understanding the conditions that cause these cells to go off to different fates may have a bearing on health problems such as ectopic pregnancy, which occurs when the embryo develops outside of the womb in about 1 of 60 pregnancies, or molar pregnancy, which is abnormal tissue growth within the uterus that affects about 1 in every 1,000 pregnancies.
"We originally were exploring factors that might cause embryonic stem cells to become malignant — there is a concern that these cells may cause tumors," said Chi-Wei Lu, Ph.D., an associate neuroscientist at the UF College of Medicine and lead author of the study. "Our experiments led us to discover the signal that initiates the process of embryonic tissue differentiation."
By activating a gene called Ras in cells bathed in a very specific culture medium, scientists were able to cause embryonic stem cells — which originate from the inner cell mass of the blastocyst — to become more like the trophoblastic stem cells that give rise to the placenta from the outer portion of the blastocyst.
Researchers marked these newly minted cells, which they called ES-TS cells, and injected them into mouse embryos. Instead of joining the stem cells that build the embryo, ES-TS cells joined the stem cells that build the placenta. Furthermore, when scientists transferred the engineered mouse embryos to foster mothers, the ES-TS cells went to work exclusively laying the foundation for the placenta.
"This paper highlights the value of embryonic stem cells for understanding early development," said senior author George Q. Daley, M.D., Ph.D., an associate professor of biological chemistry and molecular pharmacology at Harvard Medical School and an associate professor of pediatrics at Children's Hospital Boston. "Embryonic stem cells are more plastic than we had thought. By simply activating the Ras gene, we changed the fate of embryonic stem cells to an entirely unexpected tissue — the placenta. This surprising result has given us an unanticipated insight into early embryo development."
The technique of genetically modifying the cells and growing them in a special medium could be valuable for additional research.
"This is exciting because events that only occur in the early stages of embryonic development are very difficult to study," Lu said. "Just a few models exist, and even in mice, only a limited amount of embryos can be harvested. Now we can culture these cells and have unlimited material to study."
Researchers are only beginning to understand the natural chemical environments that allow for production of different tissues.
"What is nice is that what she has observed in cultures appears to be quite similar to what goes on in early development in animals," said R. Michael Roberts, D.Phil., a professor of molecular biology at the C.S. Bond Life Sciences Center at the University of Missouri-Columbia who did not participate in the research. "Normally, mouse embryonic stem cells aren't easily converted along the pathway to form placental cells, while human embryonic stem cells undergo this transition quite easily. This has always been a puzzle. What she has shown is you can make mouse embryonic stem cells convert unidirectionally to trophoblasts by activating a single gene. This is very helpful for understanding how the placenta develops."
John Pastor | EurekAlert!
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine