Expression of oestrogen‐related receptor alpha in human epidermis

Skin is a non-classical target for oestrogens. Despite evidence showing that oestrogen receptors (ER) are expressed in skin, there are still extensive gaps in our understanding of how oestrogens exert their action in non-reproductive tissues. Oestrogen-related receptor-alpha (ERRalpha), orphan member of the nuclear receptor superfamily, shows a strong sequence homology with ERalpha but it does not bind oestradiol. Here, for the first time, we demonstrate ERRalpha expression in the epidermis of adult human skin. ERRalpha mRNA was detected in the epidermis of eight female donors using reverse transcriptase polymerase chain reaction. The presence of the protein was confirmed using western blotting and immunohistochemistry on 5 and 11 adult human skins, respectively. This study shows that ERRalpha is expressed in human epidermis and could intervene in a potentially new oestrogen signalling pathway in the skin.