title: Cardioprotection and mitochondrial S-nitrosation: effects of S-nitroso-2-mercaptopropionyl glycine (SNO-MPG) in cardiac ischemia-reperfusion injury.
abstract: Mitochondrial dysfunction is a key pathologic event in cardiac ischemia-reperfusion (IR) injury, and protection of mitochondrial function is a potential mechanism underlying ischemic preconditioning (IPC). Acknowledging the role of nitric oxide (NO()) in IPC, it was hypothesized that mitochondrial protein S-nitrosation may be a cardioprotective mechanism. The reagent S-nitroso-2-mercaptopropionyl-glycine (SNO-MPG) was therefore developed to enhance mitochondrial S-nitrosation and elicit cardioprotection. Within cardiomyocytes, mitochondrial proteins were effectively S-nitrosated by SNO-MPG. Consistent with the recent discovery of mitochondrial complex I as an S-nitrosation target, SNO-MPG inhibited complex I activity and cardiomyocyte respiration. The latter effect was insensitive to the NO() scavenger c-PTIO, indicating no role for NO()-mediated complex IV inhibition. A cardioprotective role for reversible complex I inhibition has been proposed, and consistent with this SNO-MPG protected cardiomyocytes from simulated IR injury. Further supporting a cardioprotective role for endogenous mitochondrial S-nitrosothiols, patterns of protein S-nitrosation were similar in mitochondria isolated from Langendorff perfused hearts subjected to IPC, and mitochondria or cells treated with SNO-MPG. The functional recovery of perfused hearts from IR injury was also improved under conditions which stabilized endogenous S-nitrosothiols (i.e. dark), or by pre-ischemic administration of SNO-MPG. Mitochondria isolated from SNO-MPG-treated hearts at the end of ischemia exhibited improved Ca(2+) handling and lower ROS generation. Overall these data suggest that mitochondrial S-nitrosation and complex I inhibition constitute a protective signaling pathway that is amenable to pharmacologic augmentation.
authors.affiliation: Department of Anesthesiology, PO Box 604, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
authors.forename: Sergiy M
authors.initials: SM
authors.lastname: Nadtochiy
authors.forename: Lindsay S
authors.initials: LS
authors.lastname: Burwell
authors.forename: Paul S
authors.initials: PS
authors.lastname: Brookes
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000502:physiology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism; D015538:Nitrosation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D008625:Tiopronin / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D002316:Cardiotonic Agents; D017382:Reactive Oxygen Species; D008625:Tiopronin; D002118:Calcium