title: Peroxynitrate-mediated DNA strand breakage activates poly(ADP-ribose) synthetase and causes cellular energy depletion in a nonseptic shock model induced by zymosan in the rat.
abstract: The aim of the present study was to investigate the role of poly(ADP-ribose) synthetase in a nonseptic shock model, wherein oxyradicals, nitric oxide, and peroxynitrite are known to play a crucial role in the inflammatory process. DNA single-strand breakage and activation of the nuclear enzyme poly(ADP-ribose) synthetase (PARS) triggers an energy-consuming, inefficient repair cycle, which contributes to peroxynitrite-induced cellular injury. Here we investigated whether peroxynitrite production and PARS activation are involved in cytotoxicity in macrophages collected from rats subjected to zymosan-induced shock. Macrophages harvested from the peritoneal cavity exhibited a significant production of peroxynitrite, as measured by the oxidation of the fluorescent dye dihydrorhodamine 123. Furthermore, zymosan-induced shock caused a suppression of macrophage mitochondrial respiration, DNA strand breakage, activation of PARS, and reduction of NAD+ cellular levels. In vivo treatment with 3-aminobenzamide (10 mg/kg intraperitoneally, 1 and 6 h after zymosan injection) or nicotinamide (50 mg/kg intraperitoneally, 1 and 6 h after zymosan injection) significantly inhibited the decrease in mitochondrial respiration and the activation of PARS, and partially restored the cellular level of NAD+. In a separate group of experiments, in vivo pretreatment with NG-nitro-L-arginine methyl ester, a nonselective inhibitor of nitric oxide synthesis (10 mg/kg intraperitoneally, 15 min before zymosan administration), reduced peroxynitrite formation and prevented the appearance of DNA damage, the decrease in mitochondrial respiration, and the loss of cellular levels of NAD+. Our study suggests that formation of peroxynitrite and subsequent activation of PARS may alter macrophage function in inflammatory processes and inhibition of nitric oxide, and that PARS may be a novel pharmacological approach to prevent cell injury in inflammation.
authors.affiliation: Institute of Pharmacology, School of Medicine, University of Messina, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Cuzzocrea
authors.forename: B
authors.initials: B
authors.lastname: Zingarelli
authors.forename: A P
authors.initials: AP
authors.lastname: Caputi
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D004249:DNA Damage; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000187:drug effects*; D004789:Enzyme Activation; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009536:Niacinamide / Q000494:pharmacology; D009566:Nitrates / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D016877:Oxidants / Q000502:physiology; D010101:Oxygen Consumption; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012769:Shock / Q000503:physiopathology*; D015054:Zymosan
chemical_list: D001549:Benzamides; D009566:Nitrates; D016877:Oxidants; D009243:NAD; D009536:Niacinamide; C039642:peroxynitric acid; C025160:3-aminobenzamide; D015054:Zymosan; D019001:Nitric Oxide Synthase; D011065:Poly(ADP-ribose) Polymerases; D019331:NG-Nitroarginine Methyl Ester