Why do follicles age
Biologists have blamed stem cells for the age-related baldness of men
The reason for baldness of men and some women in middle and old age was that the stem cells that "produce" hair on our head gradually turn into skin cells as a result of damage to their DNA, according to an article published in the journal Science (Matsumura et al., Hair follicle aging is driven by transepidermal elimination of stem cells via COL17A1 proteolysis).
"We all know very well that hair gradually thin out as our body ages. No one doubted this, but we had no idea how this process goes on at the molecular and cellular level," commented on the discovery of Cheng–Ming Chuong from the University of Southern California in Los Angeles (USA), whose words are quoted by the press service of the journal Science (One reason your hair is thinning? Some of it turns into skin – VM).
Yi Rui from the University of Colorado at Boulder (USA) and his colleagues have uncovered the cause of late baldness in men and found a mechanism explaining the thinning of hair in old age by experimenting with hair follicle cells on the skin of mice.
The hair follicles of all mammals, as scientists explain, contain special stem cells that are responsible for the growth of new hair and that are able to switch between two modes – periods of calm when the hair has reached the "right" length, and periods of growth when the body needs to grow a new coat or hair cover.
Scientists have tried to force cells to "switch" between these modes by removing and turning on various genes. During these experiments, they found that a similar switch is the Foxc1 gene, which is active during hair growth, and is completely turned off during the calm phase due to the appearance of special epigenetic marks on its surface.
Geneticists have tested what happens if the work of this gene is blocked by damaging it or neutralizing it in other ways. This technique led to unusual results – initially, scientists expected that the stem cells in the hair follicles would die as a result of the inclusion of apoptosis, a genetic program of cell suicide, but this did not happen.
Instead, the cells decided to "repurpose" and turned into ordinary skin cells, thereby depriving the hair bulb of the ability to produce new hair. This was due to the fact that disabling Foxc1 caused malfunctions in the gene and protein COL17A1 (collagen type XVII alpha 1 – VM), attaching stem cells to the bulb wall, which forced them to change the "sphere of employment" after COL17A1 stopped holding them.
This process, according to the authors of the article, is the reason why people gradually lose their hair in old age and why many men go bald in middle and old age, when the regenerative abilities of their stem cells begin to decline. Accordingly, supporting the work of COL17A1 can, in principle, help doctors stop baldness and help people keep their hair thick.
Portal "Eternal youth" http://vechnayamolodost.ru
05.02.2015