Deficient ryanodine receptor S-nitrosylation increases sarcoplasmic reticulum calcium leak and arrhythmogenesis in cardiomyocytes.
Altered Ca(2+) homeostasis is a salient feature of heart disease, where the calcium release channel ryanodine receptor (RyR) plays a major role. Accumulating data support the notion that neuronal nitric oxide synthase (NOS1) regulates the cardiac RyR via S-nitrosylation. We tested the hypothesis that NOS1 deficiency impairs RyR S-nitrosylation, leading to altered Ca(2+) homeostasis. Diastolic Ca(2+) levels are elevated in NOS1(-/-) and NOS1/NOS3(-/-) but not NOS3(-/-) myocytes compared with wild-type (WT), suggesting diastolic Ca(2+) leakage. Measured leak was increased in NOS1(-/-) and NOS1/NOS3(-/-) but not in NOS3(-/-) myocytes compared with WT. Importantly, NOS1(-/-) and NOS1/NOS3(-/-) myocytes also exhibited spontaneous calcium waves. Whereas the stoichiometry and binding of FK-binding protein 12.6 to RyR and the degree of RyR phosphorylation were not altered in NOS1(-/-) hearts, RyR2 S-nitrosylation was substantially decreased, and the level of thiol oxidation increased. Together, these findings demonstrate that NOS1 deficiency causes RyR2 hyponitrosylation, leading to diastolic Ca(2+) leak and a proarrhythmic phenotype. NOS1 dysregulation may be a proximate cause of key phenotypes associated with heart disease.
Gonzalez
Daniel R
DR
Department of Medicine, Cardiovascular Division, and Interdisciplinary Stem Cell Institute, Miller School of Medicine, University of Miami, 1120 Northwest 14th Street, Suite 1124, Miami, FL 33136, USA.
Beigi
Farideh
F
Treuer
Adriana V
AV
Hare
Joshua M
JM
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000201:enzymology / Q000209:etiology* / Q000235:genetics; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D003971:Diastole; D051379:Mice; D008822:Mice, Transgenic; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D010084:Oxidation-Reduction; D010766:Phosphorylation; D019837:Ryanodine Receptor Calcium Release Channel / Q000172:deficiency* / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism
D002118:Calcium; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D019837:Ryanodine Receptor Calcium Release Channel; D013438:Sulfhydryl Compounds; D022021:Tacrolimus Binding Proteins; C509259:FKBP1B protein, mouse; C496315:Nos3 protein, mouse