title: Do β-cells generate peroxynitrite in response to cytokine treatment?
abstract: The purpose of this study was to determine the reactive species that is responsible for cytokine-mediated β-cell death. Inhibitors of inducible nitric oxide synthase prevent this death, and addition of exogenous nitric oxide using donors induces β-cell death. The reaction of nitric oxide with superoxide results in the generation of peroxynitrite, and this powerful oxidant has been suggested to be the mediator of β-cell death in response to cytokine treatment. Recently, coumarin-7-boronate has been developed as a probe for the selective detection of peroxynitrite. Using this reagent, we show that addition of the NADPH oxidase activator phorbol 12-myristate 13-acetate to nitric oxide-producing macrophages results in peroxynitrite generation. Using a similar approach, we demonstrate that cytokines fail to stimulate peroxynitrite generation by rat islets and insulinoma cells, either with or without phorbol 12-myristate 13-acetate treatment. When forced to produce superoxide using redox cyclers, this generation is associated with protection from nitric oxide toxicity. These findings indicate that: (i) nitric oxide is the likely mediator of the toxic effects of cytokines, (ii) β-cells do not produce peroxynitrite in response to cytokines, and (iii) when forced to produce superoxide, the scavenging of nitric oxide by superoxide is associated with protection of β-cells from nitric oxide-mediated toxicity.
authors.affiliation: From the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Broniowska
authors.forename: Clayton E
authors.initials: CE
authors.lastname: Mathews
authors.forename: John A
authors.initials: JA
authors.lastname: Corbett
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D007372:Interferons / Q000494:pharmacology* / Q000633:toxicity; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D013481:Superoxides; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D007372:Interferons; D019001:Nitric Oxide Synthase; D013755:Tetradecanoylphorbol Acetate
keywords: Cytokine; Diabetes; Islet; Nitric Oxide; Nitric-oxide Synthase; Peroxynitrite; Reactive Oxygen Species (ROS)