It is worth recalling that a stem cell is a special type of cells capable of asymmetric division, during which not two identical “daughters” are formed from one “mother cell”, but one copy of the mother and one cell somewhat updated for a specific purpose. In addition, under certain conditions, this cell type can transform into other cell types.
If we are talking about the cells of an adult organism, then stem cells are predominantly multipotent, as well as having less “potency”.
Hematopoietic and mesenchymal cells
In the adult body, stem cells of interest are hematopoietic – those that give rise to blood cells, and mesenchymal – those that maintain our connective tissues, including bones, cartilage, fat deposits, and also an important part of the skin – the dermis. An interesting feature of these cells is that they are located both in the so-called depots – places where a special population of these cells remains “for future use”, and in some tissues locally. The main depots of mesenchymal multipotent cells include bone marrow, adipose tissue, but they are also present in the skin dermis and in some other places.
There are also special populations of multipotent cells in hair follicles, as well as in the intestines (intestinal stem cells, which are actively researched). One of the problems that arise when studying populations of multipotent cells in an adult organism is that their state is very dynamic. Relatively speaking, at one moment this cell is actually a dormant stem cell, at another it is already “running to the rescue” at a signal from the place of damage, and then it works directly at the location.
About the mechanism of cell work
The mechanism of mesenchymal cells is to perform a dual task – the direct replacement of the required type of damaged cells, and the so-called regenerative management: tissue regeneration occurs with the participation of the mesenchymal cell and under its “guidance” by releasing signal molecules to affect other cells in the tissue in need of help. For example, in order to effectively heal a wound, a whole range of cells must be involved in the process – and each of the cell types must do its job perfectly.
Often one of the regulators and controllers of the quality of this work can also be a multipotent cell. It releases special chemical factors that serve as “keys” for the “locks” of receptors on the surfaces of other cells and thus start or stop certain processes in them.
At the same time, the surface of the stem cell itself also has its own receptors that perceive information from the microenvironment, react to it by activating or inhibiting various processes, and orient themselves in space.
For example, along a gradient of certain signals, stem cells move to the sites of damage. This phenomenon is called homing and consists in the fact that in case of serious damage, when the local population of multipotent and oligopotent cells can no longer cope with the work, the cells “sleeping” in the depot (which may be located geographically remote from the site of damage) set out on their way to help .
The mesenchymal cell itself is also very sensitive to the physical characteristics of the tissue in which it is located. According to the degree of hardness, for example, it can “choose” the direction of the required transformation.
TO SEE THE VIDEO – HOW DO STEM CELLS WORK IN THE BODY!