Discovery of a chemical controlling life and death in hair follicles

Discovery of a chemical controlling life and death in hair follicles

Head of a bald man

New research into the factors that control the life and death of hair follicle cells could help people with baldness, as well as wound healing.

Discovery could help end baldness and speed healing

Scientists have discovered that a single chemical is essential for controlling when hair follicle cells divide and when they die. This breakthrough could not only lead to an effective treatment for baldness, but also accelerate wound healing, as follicles are a source of stem cells.

In the human body, most cells have a specific form and function determined during embryonic development that does not change. A blood cell, for example, cannot turn into a nerve cell, or vice versa. However, stem cells are like the blank tiles in a Scrabble game; they can transform into other types of cells.

The adaptability of stem cells makes them valuable for repairing damaged tissues or organs.

Hair follicle cross section

Cross section of a hair follicle. Credit: UCR

“In science fiction, when characters quickly heal from wounds, the idea is that stem cells made it possible,” said Qixuan Wang, a mathematical biologist from Riverside and co-author of the study at the University. from California.

“In real life, our new research brings us closer to understanding stem cell behavior, so we can control it and promote wound healing,” Wang said. This research is detailed in an article recently published in the Biophysical Journal.

In response to injury, the liver and stomach regenerate. However, Wang’s team of researchers studied hair follicles because they are the only organ in humans that automatically and periodically regenerates, even without injury.

Scientists have discovered how TGF-beta, a type of protein, controls the process by which hair follicle cells, including stem cells, divide and form new cells, or orchestrate their own death, ultimately leading to death of the entire hair follicle.

“TGF-beta has two opposing roles. It helps activate certain hair follicle cells to produce new life, and later it helps orchestrate apoptosis, the process of cell death,” Wang said.

As with many chemicals, it is the quantity that makes the difference in the result. If the cell produces a certain amount of TGF-beta, it activates cell division. However, too much of it causes apoptosis.

No one knows exactly why hair follicles kill themselves. It is hypothesized to be an inherited trait of animals that shed their fur to survive hot summer temperatures or attempt to camouflage themselves.

“Even when a hair follicle kills itself, it never kills its reservoir of stem cells. When the surviving stem cells receive the signal to regenerate, they divide, make new cells and grow into a new follicle,” Wang said.

If researchers can determine more precisely how TGF-beta activates cell division and how the chemical communicates with other important genes, it might be possible to activate follicle stem cells and stimulate hair growth.

Since many animals, including humans, have hair-covered skin, perfect wound healing would require the regeneration of hair follicles. Being able to more precisely control TGF-beta levels could also cure baldness, which troubles millions of people around the world, in a day.

“Potentially our work could offer something to help people with various issues,” Wang said.

Reference: “A probabilistic Boolean model on the regulation of hair follicle cell fate by TGF-ß” by Katherine Dinh and Qixuan Wang, June 16, 2022, Biophysical Journal.
DOI: 10.1016/j.bpj.2022.05.035

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