title: Tryptophan hydroxylase expression in human skin cells.
abstract: We attempted to further characterize cutaneous serotoninergic and melatoninergic pathways evaluating the key biosynthetic enzyme tryptophan hydroxylase (TPH). There was wide expression of TPH mRNA in whole human skin, cultured melanocytes and melanoma cells, dermal fibroblasts, squamous cell carcinoma cells and keratinocytes. Gene expression was associated with detection of TPH immunoreactive species by Western blotting. Characterization of the TPH immunoreactive species performed with two different antibodies showed expression of the expected protein (55-60 kDa), and of forms with higher and lower molecular weights. This pattern of broad spectrum of TPH expression including presumed degradation products suggests rapid turnover of the enzyme, as previously reported in mastocytoma cells. RP-HPLC of skin extracts showed fluorescent species with the retention time of serotonin and N-acetylserotonin. Immunocytochemistry performed in skin biopsies localized TPH immunoreactivity to normal and malignant melanocytes. We conclude that while the TPH mRNA and protein are widely expressed in cultured normal and pathological epidermal and dermal skin cells, in vivo TPH expression is predominantly restricted to cells of melanocytic origin.
authors.affiliation: Department of Pathology, University of Tennessee Health Science Center, 930 Madison Ave., #519 Memphis, TN 38163, USA. aslominski@utmem.edu
authors.forename: Andrzej
authors.initials: A
authors.lastname: Slominski
authors.forename: Alexander
authors.initials: A
authors.lastname: Pisarchik
authors.forename: Olle
authors.initials: O
authors.lastname: Johansson
authors.forename: Chen
authors.initials: C
authors.lastname: Jing
authors.forename: Igor
authors.initials: I
authors.lastname: Semak
authors.forename: George
authors.initials: G
authors.lastname: Slugocki
authors.forename: Jacobo
authors.initials: J
authors.lastname: Wortsman
mesh_terms: D001706:Biopsy; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000201:enzymology / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000201:enzymology* / Q000473:pathology; D012878:Skin Neoplasms / Q000201:enzymology / Q000473:pathology; D014365:Tryptophan Hydroxylase / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D014365:Tryptophan Hydroxylase