Longevity Briefs: ‘Stuck’ Stem Cells May Be The Cause Of Your Grey Hairs

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Grey hairs are one of the most well known signs of ageing. The cells responsible for hair pigmentation are called melanocytes. A population of self-renewing melanocyte stem cells resides within each hair follicle. Each time a hair is shed and a new hair begins to grow, some melanocyte stem cells migrate to the base of the hair, becoming fully developed melanocytes that produce pigment. Depletion of self-renewing stem cells is considered to be an important contributor to the ageing process, but for unknown reasons, this seems to happen much earlier in hair follicles than in most other tissues in the body.

What did the researchers do: In this study, researchers wanted to investigate how the renewal and migration of melanocytes took place in more detail. Using a combination of imaging and genetic sequencing techniques, they studied how melanocyte stem cells developed over time and how this related to their location within the hair follicles of live mice.

Key takeaway(s) from this research: When migrating and developing into pigment-producing melanocytes, melanocyte stem cells go through an intermediate, partly developed state. The researchers found that unlike most other stem cells, melanocytes in this transition state could revert back to being more primitive stem cells. Stem cells could repeatedly transition between these two states, and doing so depended on signals from the surrounding cells as the melanocytes moved back and forwards between different compartments within the hair follicle.

The researchers found that with advancing age, an increasing number of stem cells became ‘stuck’ in a compartment called the hair follicle bulge. Here, they were unable to develop into the transition state, but were also unable to move back into their original compartment, meaning they were cut off from the signals necessary for self renewal.

If this also occurs in humans, it could provide a new means to reverse hair greying by helping these melanocytes become ‘unstuck’.