O#29   Human non-balding scalp dermal papilla cells express estrogen receptor b (ERb) protein in vivo and in vitro

Julie Thornton1, Louisa Nelson1, Anthony Taylor2, Kellie Mulligan2, Farook Al-Azzawi2, Andrew Messenger3. 1 Dept of Biomedical Sciences, University of Bradford; 2 Dept of Obstetrics & Gynaecology, Leicester Royal Infirmary; 3 Dept of Dermatology, Royal Hallamshire Hospital, Sheffield

It has been known for some time that estrogens inhibit hair growth and that the dermal papilla is probably the target for estrogen action. However, it is not known whether estrogens mediate their actions in human skin via the classical estrogen receptor (ERa) or the structurally related ERb. Therefore, we have compared the expression of ERa and ERb in sections of human non-balding scalp skin from both sexes and in cultured scalp dermal papilla cells using immunohistochemistry and RT-PCR. Paraffin-embedded sections or acetone fixed cultured cells were incubated with either mouse anti-human ERa (1:50) or rabbit anti-human ERb (1:50) antibodies, amplified with specific secondary antibodies and avidin-biotin complexes and immunoreactive sites visualised with diaminobenzadine (DAB). For RT-PCR cultured cells were incubated in serum-free, phenol red-free medium prior to RNA extraction. Endometrium, ovary and prostate, or human breast cancer MCF-7 and human colon cancer HCT116 cells were used as positive controls. In contrast to ERa, ERb was widely expressed in situ. Strong nuclear expression of ERb was seen in the epidermis, blood vessels, sebaceous and eccrine glands in both sexes. In the hair follicle ERb was localised to the cells of the dermal papilla, epithelial matrix and outer root sheath. Immunohistochemistry demonstrated that cultured dermal papilla cells retained expression of ERb in culture over several passages. Interestingly, cultured dermal papilla cells expressed mRNA transcripts for ERa. These results demonstrate that ERb is the predominant estrogen receptor protein in human skin and the hair follicle, although ERa may also have a role. In addition since dermal papilla cells retain estrogen receptor expression in vitro, they will provide a useful model for investigating the mechanism of estrogen action in the hair follicle.