Dickkopf-1 is involved in dexamethasone-mediated hair follicle regression

The stress-related neurohormones including glucocorticoids (GCs) are secreted by hair follicles (HFs), and GCs suppress murine hair growth in vivo. In this study, we found that dexamethasone (Dex), a synthetic GC, increased the expression of dickkopf-1 (DKK1), a known catagen inducer, in dermal papilla (DP) cells, but not in follicular keratinocytes. The neutralizing DKK1 antibody significantly attenuated the Dex-induced inhibition of human hair shaft elongation. In addition, the neutralizing Dkk1 antibody delayed Dex-induced catagen in mice. Collectively, our data strongly suggest that stress-related neurohormones cause DP cells to secrete DKK1, thereby leading to stress-associated disturbances in hair growth.