The "aging gene" of stem cells
Biologists have identified a gene that controls the aging of "adult" stem cells
Scientists hope that with the help of their discovery it will be possible to better treat damaged organs
Molecular biologists have found out that a decrease in the activity and a decrease in the number of "adult" stem cells in the body of elderly people was associated with the work of the GATA6 gene. If it is "turned on", then they begin to age much faster. The results of the study were published by the scientific journal Stem Cells (Jiao et al., GATA6 regulates aging of human mesenchymal stem/stromal cells).
Over the past 20 years, molecular biologists have discovered several mechanisms by which stem cell cultures can be transformed into "adult" tissues of bones, muscles, skin and the nervous system. In the future, they can be used as a kind of spare parts for the treatment of serious injuries or various degenerative diseases.
For example, scientists have been suggesting for a long time that such problems can be solved with the help of so-called mesenchymal stem cells (MSC). These are "adult" stem cells, small amounts of which are present in all human organs. At the same time, MSC cells retain the ability to transform into many types of tissues.
In the elderly, their number and activity level are gradually falling. Scientists did not know the reasons for this phenomenon. In a new study, molecular biologist Wan-Ju Li from the University of Wisconsin-Madison (USA) and his colleagues found it.
The "old age" gene of stem cells
Nobel laureate Shinya Yamanaka in the middle of the XX century found out that the culture of almost any "adult" cells of the human body and other living beings can be turned into stem cells if four key genes are activated in them: MYC, OCT4, SOX2 and KLF4. Subsequently, these genes were called "Yamanaki factors". As a result of such a procedure, the cells are rejuvenated and lose their original functions. Thanks to this, they can be turned into blanks of any fabrics.
As American biologists have recently found out, using the same procedure, it is possible to rejuvenate "adult" stem cells without changing their characteristics. Thanks to this, Lee and his colleagues studied in detail how the activation of "Yamanaki factors" changes the work of genes and proteins of MSC cells.
For the experiments, biologists extracted MSC cells from synovial fluid - a thick mass that fills the joint cavity – of several elderly volunteers. Then the scientists activated Yamanaki factors in them.
It turned out that this procedure really restored youth to "adult" stem cells. As a result, they began to divide more actively, produced fewer pro-inflammatory molecules and performed other functions that gradually fade as they age. All these positive changes, in turn, were due to the fact that the "reprogramming" of cells suppressed the work of the GATA6 gene, which is associated with the development of some internal organs of the human body.
In favor of this, in particular, says that when scientists suppressed this gene with the help of short RNA molecules, the cells "rejuvenated" in a similar way. Scientists have achieved similar results in experiments on mice using only two Yamanaki factors, OCT4 and KLF4.
In the future, such a discovery will make it possible to rejuvenate MSC cells of elderly people, without the risk that they will turn into full-fledged reprogrammed stem cells that can divide uncontrollably. This will significantly expand their therapeutic use and the ability to repair damage in the organs in which they live, the biologists summed up.
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