title: Reversible redox modifications of ryanodine receptor ameliorate ventricular arrhythmias in the ischemic-reperfused heart.
abstract: Previous results from our laboratory showed that phosphorylation of ryanodine receptor 2 (RyR2) by Ca(2+) calmodulin-dependent kinase II (CaMKII) was a critical but not the unique event responsible for the production of reperfusion-induced arrhythmogenesis, suggesting the existence of other mechanisms cooperating in an additive way to produce these rhythm alterations. Oxidative stress is a prominent feature of ischemia/reperfusion injury. Both CaMKII and RyR2 are proteins susceptible to alteration by redox modifications. This study was designed to elucidate whether CaMKII and RyR2 redox changes occur during reperfusion and whether these changes are involved in the genesis of arrhythmias. Langendorff-perfused hearts from rats or transgenic mice with genetic ablation of CaMKII phosphorylation site on RyR2 (S2814A) were subjected to ischemia-reperfusion in the presence or absence of a free radical scavenger (mercaptopropionylglycine, MPG) or inhibitors of NADPH oxidase and nitric oxide synthase. Left ventricular contractile parameters and monophasic action potentials were recorded. Oxidation and phosphorylation of CaMKII and RyR2 were assessed. Increased oxidation of CaMKII during reperfusion had no consequences on the level of RyR2 phosphorylation. Avoiding the reperfusion-induced thiol oxidation of RyR2 with MPG produced a reduction in the number of arrhythmias and did not modify the contractile recovery. Conversely, selective prevention of S-nitrosylation and S-glutathionylation of RyR2 was associated with higher numbers of arrhythmias and impaired contractility. In S2814A mice, treatment with MPG further reduced the incidence of arrhythmias. Taken together, the results suggest that redox modification of RyR2 synergistically with CaMKII phosphorylation modulates reperfusion arrhythmias.
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Romina
authors.initials: R
authors.lastname: Becerra
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Bárbara
authors.initials: B
authors.lastname: Román
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Mariano N
authors.initials: MN
authors.lastname: Di Carlo
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Juan Ignacio
authors.initials: JI
authors.lastname: Mariangelo
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Margarita
authors.initials: M
authors.lastname: Salas
authors.affiliation: Programa de Fisiopatología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile;
authors.forename: Gina
authors.initials: G
authors.lastname: Sanchez
authors.affiliation: Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile;
authors.forename: Paulina
authors.initials: P
authors.lastname: Donoso
authors.affiliation: Facultad de Ciencias Médicas, Universidad Nacional de La Plata, CIC-PBA, La Plata, Argentina;
authors.forename: Guillermo R
authors.initials: GR
authors.lastname: Schinella
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Leticia
authors.initials: L
authors.lastname: Vittone
authors.affiliation: Cardiovascular Research Institute, Department of Molecular Physiology and Biophysics, Department of Medicine (in Cardiology), Pediatrics, Baylor College of Medicine, Houston, Texas.
authors.forename: Xander H
authors.initials: XH
authors.lastname: Wehrens
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina;
authors.forename: Cecilia
authors.initials: C
authors.lastname: Mundiña-Weilenmann
authors.affiliation: Centro de Investigaciones Cardiovasculares, CCT-CONICET La Plata, Facultad de Medicina, Universidad Nacional de La Plata, La Plata, Argentina; matildesaid@gmail.com.
authors.forename: Matilde
authors.initials: M
authors.lastname: Said
mesh_terms: D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000187:drug effects / Q000378:metabolism*; D004586:Electrophoresis; D016166:Free Radical Scavengers / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D000067268:Isolated Heart Preparation; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009200:Myocardial Contraction / Q000187:drug effects / Q000235:genetics*; D015428:Myocardial Reperfusion Injury / Q000235:genetics* / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D008625:Tiopronin / Q000494:pharmacology
chemical_list: D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; C000612605:RyR2 protein, rat; D019837:Ryanodine Receptor Calcium Release Channel; C000592748:ryanodine receptor 2. mouse; D008625:Tiopronin; D019001:Nitric Oxide Synthase; D019255:NADPH Oxidases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D005978:Glutathione; D002118:Calcium
keywords: arrhythmias; ischemia/reperfusion; redox modifications; ryanodine receptor type 2