If this is true, what about rapamycin could be counteracting it?
The observation that melanocyte stem cells migrate up and down the hair follicle, differentiating into melanocytes and then returning to a stem-cell identity, calls into question long-held assumptions about adult stem cells.
The issue afaics is the failure to differentiate. Rapa in making cells more efficient results in more cytosolic acetyl-coa so the histone can be acetylated by the KAT as part of the RNA polymerase II complex.
To be clear, the McSCs aren’t the sole factor in determining when your gray grows in. Dr. Jenna Lester, a dermatologist and professor at the University of California, San Francisco, told NPR’s Short Wave podcast that there’s a multitude of factors beyond aging that play a role.
“Some people think sun exposure can damage their melanocytes more or less,” she said. “And hormones also play into it as well.” Then there’s stress, genetics and certain medical conditions, which can all strip hair of its richer hues.
Overall, 74% of people between the ages of 45 and 65 years of age have at least a few silver strands, according to research from the National Institutes of Health.
If you’re in that camp and resenting it, this new study could be a reason to rejoice: The researchers say that moving the McSCs to their proper location could prevent graying.