Oxidative stress mediates cell surface expression of SS-A/Ro antigen on keratinocytes.
Exposure to ultraviolet radiation exacerbates the skin lesions of autoimmune diseases, and is known to induce cell surface expression of SS-A/Ro antigen on keratinocytes in vitro. Following up on recent reports on ultraviolet-B (UVB)-induced oxidative stress, we examined the role of oxidative stress in the surface expression of SS-A/Ro antigen on human keratinocytes. First, the exclusive induction by UVB irradiation of the 52-kDa protein (Ro52) but not of the 60-kDa protein (Ro60) of SS-A/Ro antigen was demonstrated by means of indirect immunofluorescence. The surface expression of Ro52 induced by UVB irradiation was concentration-dependently inhibited by N-acetyl-L-cysteine, an antioxidant. Furthermore, surface expression of Ro52 was similarly induced by diamide, a chemical oxidant. We next used Hoechst 33342 staining and the TUNEL assay to demonstrate that a low dose (20 mJ/cm(2)) of UVB did not induce apoptosis but induced the surface expression of Ro52. Moreover, zVAD-fmk, a pan-caspase inhibitor, did not inhibit UVB-induced surface expression of Ro52 even at a high dose (200 mJ/cm(2)) of UVB, which was sufficient to induce apoptosis in keratinocytes in the absence of zVAD-fmk. Taken together, we concluded that UVB-induced surface expression of Ro52 on keratinocytes is mediated by oxidative stress through a pathway other than apoptosis.
Saegusa
Jun
J
Department of Clinical Pathology and Immunology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Kawano
Seiji
S
Koshiba
Masahiro
M
Hayashi
Nobuhide
N
Kosaka
Hidekazu
H
Funasaka
Yoko
Y
Kumagai
Shunichi
S
D000111:Acetylcysteine / Q000494:pharmacology; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000954:Antigens, Surface / Q000378:metabolism*; D017209:Apoptosis; D001324:Autoantigens / Q000378:metabolism*; D001327:Autoimmune Diseases / Q000209:etiology*; D001562:Benzimidazoles; D015153:Blotting, Western; D061945:Caspase Inhibitors; D002478:Cells, Cultured; D003958:Diamide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers; D006801:Humans; D020287:In Situ Nick-End Labeling; D007231:Infant, Newborn; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D018384:Oxidative Stress; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014466:Ultraviolet Rays; D000099207:SS-A Antigen
D000111:Acetylcysteine; D000590:Amino Acid Chloromethyl Ketones; D000954:Antigens, Surface; D001324:Autoantigens; D001562:Benzimidazoles; D061945:Caspase Inhibitors; D003958:Diamide; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D000099207:SS-A Antigen; C116006:RO60 protein, human; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C017807:bisbenzimide ethoxide trihydrochloride