title: Involvement of UVB-induced reactive oxygen species in TGF-beta biosynthesis and activation in keratinocytes.
abstract: TGF-beta produced by keratinocytes in response to UVB (290-320 nm) is a potential mediator for effects of acute and chronic solar radiation on skin. This study was designed to determine whether reactive oxygen species (ROS) mediate UVB-induced TGF-beta biosynthesis in keratinocytes and the subsequent activation of the latent TGF-beta complex. UVB irradiation elevated both total (latent plus active) and active TGF-beta in the keratinocyte supernatants, with a greater increase in the active form. UVB irradiation induced up to a 30% increase in ROS, and the ROS were detected up to 90 min after irradiation. NAC and Trolox, cytoplasmic ROS scavengers, abolished the UVB-induced TGF-beta and intracellular ROS, suggesting that UVB-induced ROS are involved in TGF-beta regulation. Inhibitors of NADPH oxidase activity, DPI and apocynin, decreased UVB-induced ROS. The increase in NADPH oxidase activity was mediated by EGFR activation. UVB-induced ROS also activated latent TGF-beta complex by stimulating MMP-2 and -9 activities. In summary, physiological doses of UVB increase intracellular ROS, which upregulate TGF-beta biosynthesis and activation of TGF-beta through increased activity of MMPs.
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
authors.forename: Hongjun
authors.initials: H
authors.lastname: Wang
authors.forename: Irene E
authors.initials: IE
authors.lastname: Kochevar
mesh_terms: D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism* / Q000528:radiation effects*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000378:metabolism; D014466:Ultraviolet Rays; D015854:Up-Regulation
chemical_list: D009861:Onium Compounds; D017382:Reactive Oxygen Species; D016212:Transforming Growth Factor beta; C007517:diphenyleneiodonium; D019255:NADPH Oxidases; D066246:ErbB Receptors; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9