28 July 2022

Revitalize the follicles

Most cells in the human body have a certain shape and function, which are laid during embryonic development and do not change. For example, a blood cell cannot turn into a nerve cell or vice versa. Stem cells, on the contrary, can turn into other types of cells. Understanding the behavior of stem cells will allow them to be managed for organ repair and wound healing.

There are organs in the human body (liver, stomach) that can regenerate in response to damage. However, a group from the University of California at Riverside devoted a study to hair follicles, because this is the only structure that is periodically restored even in the absence of damage.

Researchers have determined that transforming growth factor beta (TGF-β) controls the process by which cells in hair follicles, including stem cells, divide and form new cells or organize their own death, which ultimately leads to the death of the entire hair follicle.

The TGF-β protein plays two opposite roles. It activates some hair follicle cells to produce new tissue, and later triggers apoptosis, the process of planned cell death. As with many chemicals, the difference is in quantity. If a cell produces a limited amount of TGF-β, this activates cell division, and excess causes apoptosis.

It is currently unknown why the follicles kill themselves through apoptosis. Some hypotheses suggest that this is an evolutionarily inherited trait from animals shedding winter fur to survive the hot summer months or disguise themselves. But even when the hair follicle kills itself, it retains a supply of stem cells. When the surviving stem cells receive a signal to regenerate, they divide, create other cells and develop into a new follicle.

If scientists can more accurately determine how TGF-β activates cell division and interacts with important genes, it may be possible to "wake up" follicle stem cells in order to one day cure not only baldness, which worries millions of people around the world, but also accelerate wound healing, since follicles are the source of stem cells.

Article K.Dinh et al. A probabilistic Boolean model on hair follicle cell fate regulation by TGF-β is published in the Biophysical Journal.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of UC Riverside: The chemical controlling life and death in hair follicles.

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