title: UVA-mediated downregulation of MMP-2 and MMP-9 in human epidermal keratinocytes.
abstract: While human dermal fibroblasts increase the expression and secretion of distinct matrix metalloproteinases (MMPs) in response to ultraviolet (UV) irradiation, much less is known about regulation of MMPs with regard to normal human epidermal keratinocytes (NHEK). In this in vitro study, the effect of ultraviolet A (UVA) irradiation on gelatinase expression and secretion by NHEK was investigated. Irradiation of NHEK with non-toxic doses of UVA resulted in a dose-dependent downregulation of MMP-2 (gelatinase A) and MMP-9 (gelatinase B). A single dose of 30JUVA/cm(2) lowered MMP-2 activity to 26% and MMP-9 activity to 33% compared with mock-irradiated cells at 24h after irradiation. Downregulation of MMP-2 and MMP-9 steady-state mRNA levels was observed at 4h after UVA irradiation. The inhibitory effect of UVA on gelatinases was mediated by UVA-generated singlet oxygen (1O(2)). These findings suggest an inverse response to UVA irradiation in NHEK than in fibroblasts.
authors.affiliation: Institute for Biochemistry and Molecular Biology I, Heinrich-Heine-University Duesseldorf, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Steinbrenner
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Ramos
authors.forename: Dominik
authors.initials: D
authors.lastname: Stuhlmann
authors.forename: Helmut
authors.initials: H
authors.lastname: Sies
authors.forename: Peter
authors.initials: P
authors.lastname: Brenneisen
mesh_terms: D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D015536:Down-Regulation; D000078404:Epidermal Cells; D005786:Gene Expression Regulation; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology* / Q000528:radiation effects; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D026082:Singlet Oxygen / Q000502:physiology; D014466:Ultraviolet Rays
chemical_list: D012333:RNA, Messenger; D026082:Singlet Oxygen; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9