title: Increased expression of transglutaminase-1 and PPARgamma after vitamin E treatment in human keratinocytes.
abstract: In skin, vitamin E acts as the predominant lipophilic antioxidant with a protective function against irradiation and oxidative stress. In addition to that, vitamin E can also modulate signal transduction and gene expression. To study whether the four natural tocopherol analogues (alpha-, beta-, gamma-, delta-tocopherol) can influence transcriptional activity by modulating the activity of nuclear receptors, a human keratinocytes cell line (NCTC 2544) was transfected with plasmids containing the luciferase reporter gene under control by direct repeat elements (DR1-DR4), representing binding sites for four different classes of nuclear receptors. In this model, the tocopherols positively modulated only the reporter construct containing a consensus element for peroxisome proliferator-activated receptors (PPARs). The induction was strongest with gamma-tocopherol and was most likely the direct consequence of stimulation of PPARgamma protein expression in keratinocytes. Vitamin E treatment also led to increased expression of a known PPARgamma target gene involved in terminal keratinocytes differentiation, the transglutaminase-1.
authors.affiliation: Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
authors.forename: M Clara
authors.initials: MC
authors.lastname: De Pascale
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Bassi
authors.forename: Vania
authors.initials: V
authors.lastname: Patrone
authors.forename: Luis
authors.initials: L
authors.lastname: Villacorta
authors.forename: Angelo
authors.initials: A
authors.lastname: Azzi
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Zingg
mesh_terms: D000369:Aged, 80 and over; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D047495:PPAR gamma / Q000378:metabolism*; D024505:Tocopherols / Q000008:administration & dosage*; D011503:Transglutaminases / Q000378:metabolism*; D014810:Vitamin E / Q000008:administration & dosage
chemical_list: D047495:PPAR gamma; D014810:Vitamin E; D011503:Transglutaminases; C105804:transglutaminase 1; D024505:Tocopherols