The vitamin D endocrine system of human sebocytes



Locally produced vitamin D metabolites are of high importance for growth regulation in various tissues. Using real-time PCR, we have characterized expression of key components of the vitamin D system vitamin D receptor (VDR), vitamin D-25-hydroxylase (25OHase), 25-hydroxyvitamin D−1 α-hydroxylase (1αOHase), and 1,25-dihydroxyvitamin D-24-hydroxylase (24OHase) in the SZ95 human sebaceous gland cell line. Incubation of SZ95 cells with 1,25-dihydroxyvitamin D resulted in a dose-dependent suppression of cell proliferation. RNA levels for VDR, 25OHase, 1αOHase, and 24OHase were characterized in SZ95 cells treated with various vitamin D analogs. In conclusion, our findings demonstrate that key components of the vitamin D system are strongly expressed in the SZ95 human sebaceous gland cell line and that local synthesis or metabolism of vitamin D metabolites may be of importance for growth regulation and various other cellular functions in sebaceous glands. Moreover, we conclude that sebaceous glands represent promising targets for therapy with vitamin D analogs or for pharmacological modulation of calcitriol synthesis/metabolism.