W. Chen¹, C.-C. Yang², H.-M. Sheu², Ch.C. Zouboulis³

¹Department of Dermatology, Chang Gung University, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan; ²Department of Dermatology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Dermatology, Charité University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany

Objectives: The sebaceous gland is a steroidogenic organ similar to gonads and adrenal cortex, possessing all the enzymes required for steroid sex hormone synthesis and metabolism. Steroidogenic acute regulatory protein (StAR) regulates the first committed and rate-limited step of steroid biosynthesis by controlling the delivery of cholesterol from the outer to the inner membrane of mitochondria, where the P450scc complex is located. Steroidogenic factor-1 (SF-1) is a positive regulator stimulating the gene expression of StAR. Dosage sensitive sex reversal adrenal hypoplasia congenita critical region on the X-chromosome gene-1 (DAX-1) negatively regulates StAR gene expression. On the other hand, SRY-related HMG-box-transcription factor (SOX-9) can consistently upregulate SF-1 expression.

Methods: Using immunostaining, RT-PCR and in situ hybridisation, we tried to identify and localize the expression of StAR, SF-1, DAX-1 and SOX-9 in sebaceous glands and immortalized human SZ95 sebocytes.

Results: Immunocytochemistry displayed strong nuclear expression of DAX1 in basal cells of sebaceous glands. In situ hybridization study showed SOX9 mRNA mainly localized in the cytoplasm of the basal cell layer. SZ95 sebocytes expressed mRNA for StAR, SOX9 and DAX1. Treatment of the cultured SZ95 cells with 10^–6 M genistein, one of the major soya isoflavones, enhanced DAX1 protein expression at 6 h and 48 h.

Conclusion: Like sebaceous glands, SZ95 sebocytes express StAR and StAR regulatory proteins. Cultured SZ95 sebocytes may serve as a model to investigate StAR regulation and control of steroidogenesis.