Keep Quiet—How Stress Regulates Hair Follicle Stem Cells

The study by Choi et al. published in Nature demonstrated that corticosterone, a stress hormone in mice equivalent to human cortisol, regulates the activity of hair follicle stem cells (HFSCs) by controlling the gene expression of Gas6. The researchers found that chronic stress keeps HFSCs in a quiescent state, leading to prolonged resting phases of hair follicles and potential hair loss. This was observed in various mouse models, where increased levels of corticosterone resulted in longer resting phases, which could be reversed by removing the adrenal glands. The study also identified the Growth Arrest Specific Protein 6 (Gas6) as a stress-sensitive regulator of hair growth. High levels of corticosterone were found to inhibit Gas6 expression in dermal papilla cells, suggesting that stress regulates HFSC activity by suppressing Gas6. This research provides new insights into the impact of stress on hair growth and loss, highlighting the role of corticosterone and Gas6 in the regulation of HFSCs.