Hair loss might be prevented by regulating stem cell metabolism

Date:
October 13, 2020
Source:
University of Helsinki
Summary:
Medical researchers have identified a mechanism that is likely to
prevent hair loss.



FULL STORY ==========================================================================
Hair follicle stem cells, which promote hair growth, can prolong their
life by switching their metabolic state. In experiments conducted with
mice, a research group active in Helsinki and Cologne, Germany, has demonstrated that a protein called Rictor holds a key role in the process.


==========================================================================
The study was published in the Cell Metabolism journal.

Mechanisms that regulate stem cells Ultraviolet radiation and other environmental factors damage our skin and other tissues every day,
with the body continuously removing and renewing the damaged tissue. On average, humans shed daily 500 million cells and a quantity of hairs
weighing a total of 1.5 grams.

The dead material is replaced by specialised stem cells that promote
tissue growth. Tissue function is dependent on the activity and health
of these stem cells, as impaired activity results in the ageing of
the tissues.

"Although the critical role of stem cells in ageing is established, little
is known about the mechanisms that regulate the long-term maintenance
of these important cells. The hair follicle with its well understood
functions and clearly identifiable stem cells was a perfect model system
to study this important question," says Sara Wickstrom.

Reduced metabolic flexibility in stem cells underlying hair loss
At the end of hair follicles' regenerative cycle, the moment a new
hair is created, stem cells return to their specific location and
resume a quiescent state. The key finding in the new study is that
this return to the stem cell state requires a change in the cells'
metabolic state. They switch from glutamine-based metabolism and cellular respiration to glycolysis, a shift triggered by signalling induced by a
protein called Rictor, in response to the low oxygen concentration in
the tissue. Correspondingly, the present study demonstrated that the
absence of the Rictor protein impaired the reversibility of the stem
cells, initiating a slow exhaustion of the stem cells and hair loss
caused by ageing.

The research group created a genetic mouse model to study the function
of the Rictor protein, observing that hair follicle regeneration and
cycle were significantly delayed in mice lacking the protein. Ageing mice suffering from Rictor deficiency showed a gradual decrease in their stem
cell, resulting in loss of hair.

Precursors for developing hair loss drug therapies Further research will
now be conducted to investigate how these preclinical findings could
be utilised in human stem cell biology and potentially also in drug
therapies that would protect hair follicles from ageing. In other words,
the mechanisms identified in the study could possibly be utilised in
preventing hair loss.

"We are particularly excited about the observation that the application
of a glutaminase inhibitor was able to restore stem cell function in the Rictor- deficient mice, proving the principle that modifying metabolic
pathways could be a powerful way to boost the regenerative capacity of
our tissues," Wickstrom explains.


========================================================================== Story Source: Materials provided by University_of_Helsinki. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Christine S. Kim, Xiaolei Ding, Kira Allmeroth, Leah C. Biggs,
Olivia I.

Kolenc, Nina L'Hoest, Carlos Andre's Chaco'n-Marti'nez, Christian
Edlich- Muth, Patrick Giavalisco, Kyle P. Quinn, Martin S. Denzel,
Sabine A.

Eming, Sara A. Wickstro"m. Glutamine Metabolism Controls
Stem Cell Fate Reversibility and Long-Term Maintenance in
the Hair Follicle. Cell Metabolism, 2020; 32 (4): 629 DOI:
10.1016/j.cmet.2020.08.011 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201013124127.htm

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