Dexamethasone, a Synthetic Glucocorticoid, Induces the Activity of Androgen Receptor in Human Dermal Papilla Cells

Psychosocial stress stimulates the secretion of glucocorticoids (GCs), which are stress-related neurohormones. GCs are secreted from hair follicles and promote hair follicle regression by inducing cellular apoptosis. Moreover, the androgen receptor (AR) is abundant in the balding scalp, and androgens suppress hair growth by binding to AR in androgenetic alopecia. First, by using immunofluorescence, we investigated whether the treatment of dermal papilla (DP) cells with dexamethasone (DEX), a synthetic GC, causes the translocation of the glucocorticoid receptor (GR) into the nucleus. DEX treatment causes the translocation of the GR into the nucleus. Next, we investigated whether stress-induced GCs affect the AR, a key factor in male pattern baldness. In this study, we first assessed that DEX increases the expression of AR mRNA in non-balding DP cells, which rarely express AR without androgen. RU486, a GR antagonist, attenuated DEX-inducible AR mRNA expression and AR activation in human non-balding DP cells. In addition, AR translocated into the nucleus after DEX treatment. Furthermore, we indeed showed that the expression of AR was induced in the nucleus by DEX in DP cells of human and mouse hair follicles. Our results first suggest that stress-associated hair loss may be due to increased AR expression and activity induced by DEX. These results demonstrate that hair loss occurs in non-balding scalps with low AR expression.