Embryo in a test tube
Kristina and Bernard Tisset from the University of Virginia School of Medicine initiated the development of stem cells into embryo-like formations that sequentially repeat the stages of embryogenesis. Surprisingly, the researchers were able to obtain in vitro a variety of tissues that are present in a real mouse embryo.
Stem cells have a unique ability to transform into other types of cells with their diverse functions. Scientists sought to use the potential of stem cells to make them work and advance medical research. But creating complex models with multiple cell types turned out to be an incredibly difficult task. It is much easier to control the formation of one type of cell in a test tube than to conduct an orchestra necessary for the organism to develop as in nature.
The new mouse embryo model is distinguished by its subtlety and complexity of structure. A large number of tissues that are built from stem cells are organized the way they are built during natural embryogenesis – around the notochord (the precursor of the spinal column). In situ hybridization, immunolabeling, cell tracking and transcriptomic analysis show that embryoids form three germ sheets during gastrulation and demonstrate a wide range of developmental structures very similar to mouse embryos at the neurula stage. The result is the laying of a mouse embryo with properly organized cells and tissues: the digestive tract begins to develop, the heart is already beating and for the first time in vitro the nervous system develops with the formation of a neural tube.
The new Tisset model is not yet a full-fledged mouse. Important parts of the embryo, such as the forebrain, are still missing. At the moment, the development of embryoids stops at the moment corresponding to the average period of embryonic development of mice. The researchers emphasize that they will continue to improve the developed techniques in order to someday learn how to subtly manipulate the molecular signals that control the formation of embryos, which will lead to the creation of embryo-like formations containing all tissues and organs, including the forebrain.
The embryoid is the most complex mammalian model ever created in vitro. This is a new milestone in the work of scientists to simulate the natural development of mammals using stem cells. It will help to study the development of mammals more deeply, create new medicines and, ultimately, prepare a platform for growing tissues and organs for people in need of transplantation.
Article by P.-F.Xu et al. Construction of a mammalian embryo model from stem cells organized by a morphogen signaling center is published in the journal Nature Communications.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the University of Virginia: In a Dish, a Mouse, Crafted From Stem Cells, Begins to Form.