EXPRESSION OF GASTRIN-RELEASING PEPTIDE RECEPTOR IN HUMAN SKIN

Bombesin-related peptides are expressed in the skin of batrachians and mammals, As gastrin-releasing peptide belongs to this family, we sear ched for the presence and distribution of gastrin-releasing peptide re ceptors (GRPr) in the skin of healthy human adults by immunohistochemi stry, flow cytometry and electron microscopy. The results indicated th at GRPr are expressed on nerves and vessels in the dermis, on eccrine sweat glands, sebaceous glands and erector pill muscle, Within epiderm is, staining was localized only on basal and suprabasal layer cells, o r in the whole epidermis, according to the samples studied, Interestin gly, suprabasal epidermal dendritic cells occasionally showed a strong labelling. Some of these epidermal dendritic cells were identified as Langerhans' cells by immunoelectron microscopy studies, Flow cytometr y analysis of crude epidermal cell suspensions resulted in the express ion of GRPr on about 43% of the cells. Therefore, we investigated whet her human GRPr could modulate Langerhans' cells antigen-presenting fun ctions, For this purpose, we added increasing concentrations of GRP (1 0(-12) to 10(-5) M) to mixed epidermal cell lymphocyte reactions, Allo geneic T-cell proliferation was not significantly modified when added to GRP-pretreated epidermal cells. In conclusion, we demonstrated the presence of GRPr in human skin, suggesting that GRP may modulate epide rmal cell functions but does not modify antigenic presentation.