title: Autologous nitric oxide protects mouse and human keratinocytes from ultraviolet B radiation-induced apoptosis.
abstract: Nitric oxide (NO) can either prevent or promote apoptosis, depending on cell type. In the present study, we tested the hypothesis that NO suppresses ultraviolet B radiation (UVB)-induced keratinocyte apoptosis both in vitro and in vivo. Irradiation with UVB or addition of the NO synthase (NOS) inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME) increased apoptosis in the human keratinocyte cell line CCD 1106 KERTr, and apoptosis was greater when the two agents were given in combination. Addition of the chemical NO donor S-nitroso-N-acetyl-penicillamine (SNAP) immediately after UVB completely abrogated the rise in apoptosis induced by l-NAME. An adenoviral vector expressing human inducible NOS (AdiNOS) also reduced keratinocyte death after UVB. Caspase-3 activity, an indicator of apoptosis, doubled in keratinocytes incubated with l-NAME compared with the inactive isomer, d-NAME, and was reduced by SNAP. Apoptosis was also increased on addition of 1,H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase. Mice null for endothelial NOS (eNOS) exhibited significantly higher apoptosis than wild-type mice both in the dermis and epidermis, whereas mice null for inducible NOS (iNOS) exhibited more apoptosis than wild-type mice only in the dermis. These results demonstrate an antiapoptotic role for NO in keratinocytes, mediated by cGMP, and indicate an antiapoptotic role for both eNOS and iNOS in skin damage induced by UVB.
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Weller
authors.forename: Ann
authors.initials: A
authors.lastname: Schwentker
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Billiar
authors.forename: Yoram
authors.initials: Y
authors.lastname: Vodovotz
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D006152:Cyclic GMP / Q000378:metabolism; D019610:Cytoprotection; D020405:Dermis / Q000502:physiology; D004817:Epidermis / Q000502:physiology; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology / Q000528:radiation effects*; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D014018:Tissue Distribution; D014466:Ultraviolet Rays
chemical_list: D009569:Nitric Oxide; C496319:NOS2 protein, human; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496317:Nos2 protein, mouse; C496315:Nos3 protein, mouse; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D006152:Cyclic GMP