L7.      The expression of early markers of adipocyte differentiation in sebaceous gland cells.
Wesley Harrison, JJ Bull, CC Zoubolis*, MP Philpott; Centre for Cutaneous Research, Barts and The London Queen Mary’s School of Medicine and Dentistry, University of London, London, UK, *Department of Dermatology, University Medical Centre Benjamin Franklin, The Free University of Berlin, Berlin, Germany.

The transcription factors CCAAT enhancer binding protein (C/EBP) alpha, beta and delta, and peroxisome proliferator-activated receptor (PPAR) gamma are known to have a crucial role in the differentiation of adipocytes and are expressed in sebaceous gland cells(1, 2). This has led us to believe that sebocytes may follow a similar program of differentiation to adipocytes, with lipid synthesis and accumulation common to both cell types. As our understanding of adipocyte differentiation is more advanced than that of sebocytes, common pathways between the two cell types could be of significant advantage to understanding of sebocyte biology. Using RT-PCR, immunohistochemisty and western blotting we have looked for the expression of known early markers of adipocyte differentiation including resistin, galectin-12, SREBP-1 and stearoyl-CoA desaturase in the immortalised sebocyte cell line SZ95, keratinocytes and whole skin. The expression of resistin, galectin-12, SREBP-1 and stearoyl-CoA desaturase has been detected as both mRNA and protein in cultured sebocyte cell line SZ95, keratinocytes and whole skin. Distinct immunoreactivity for resistin, galectin-12 and SCD is found throughout the cytoplasm of both sebocytes and to a lesser extent keratinocytes. Whilst for SREBP-1 the immunoreactivity is predominantly in the nucleus of sebocytes. This study shows that ex-vivo and in-vitro cultured sebocytes express factors associated with early differentiation of adipocytes, adding to the evidence that sebaceous gland cells undergo a process of differentiation similar to adipocytes. We therefore, propose that further characterisation of sebocyte differentiation based on published adipocyte research may rapidly advance our understanding of sebocyte biology.

1. Chen W.J Invest Dermatol 2003;121(3):441-7.
2. Bull JJ. J Invest Dermatol 2002;118(1):17-24.