title: Nitric oxide inhibits ultraviolet B-induced murine keratinocyte apoptosis by regulating apoptotic signaling cascades.
abstract: Cytotoxic effects of nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) are considered to be one of the major causes of inflammatory diseases. On the other hand, protective effects of NO on toxic insults-induced cellular damage/apoptosis have been demonstrated recently. Ultraviolet B (UVB)-induced apoptosis of epidermal keratinocytes leads to skin inflammation and photoageing. However, it has not been elucidated what kind of effects NO has on UVB-induced keratinocyte apoptosis. Thus, in the present study, we investigated the problem and demonstrated that NO from NO donor suppressed UVB-induced apoptosis of murine keratinocytes. In addition, NO significantly suppressed activities of caspase 3, caspase 8 and caspase 9 that had been upregulated by UVB radiation. NO also suppressed p53 expression that had been upregulated by UVB radiation and upregulated Bcl-2 expression that had been down-regulated by UVB radiation. These findings suggested that NO might suppress UVB-induced keratinocyte apoptosis by regulating apoptotic signaling cascades in p53, Bcl-2, caspase3, caspase 8 and caspase 9.
authors.affiliation: Department of Dermatology, Nippon Medical School, Sendagi, Bunkyo-ku, Tokyo 113-8607, Japan. yamaokaj@nms.ac.jp
authors.forename: Junichi
authors.initials: J
authors.lastname: Yamaoka
authors.forename: Seiji
authors.initials: S
authors.lastname: Kawana
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Miyachi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D015603:Keratinocytes / Q000187:drug effects* / Q000528:radiation effects*; D051379:Mice; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: C093285:NOC 18; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; C052617:Bcl2 protein, mouse; D009569:Nitric Oxide; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases