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Nitroxyl-mediated disulfide bond formation between cardiac myofilament cysteines enhances contractile function.

Abstract：

RATIONALE:In the myocardium, redox/cysteine modification of proteins regulating Ca(2+) cycling can affect contraction and may have therapeutic value. Nitroxyl (HNO), the one-electron-reduced form of nitric oxide, enhances cardiac function in a manner that suggests reversible cysteine modifications of the contractile machinery. OBJECTIVE:To determine the effects of HNO modification in cardiac myofilament proteins. METHODS AND RESULTS:The HNO-donor, 1-nitrosocyclohexyl acetate, was found to act directly on the myofilament proteins, increasing maximum force (F(max)) and reducing the concentration of Ca(2+) for 50% activation (Ca(50)) in intact and skinned cardiac muscles. The effects of 1-nitrosocyclohexyl acetate are reversible by reducing agents and distinct from those of another HNO donor, Angeli salt, which was previously reported to increase F(max) without affecting Ca50. Using a new mass spectrometry capture technique based on the biotin switch assay, we identified and characterized the formation by HNO of a disulfide-linked actin-tropomyosin and myosin heavy chain-myosin light chain 1. Comparison of the 1-nitrosocyclohexyl acetate and Angeli salt effects with the modifications induced by each donor indicated the actin-tropomyosin and myosin heavy chain-myosin light chain 1 interactions independently correlated with increased Ca(2+) sensitivity and force generation, respectively. CONCLUSIONS:HNO exerts a direct effect on cardiac myofilament proteins increasing myofilament Ca(2+) responsiveness by promoting disulfide bond formation between critical cysteine residues. These findings indicate a novel, redox-based modulation of the contractile apparatus, which positively impacts myocardial function, providing further mechanistic insight for HNO as a therapeutic agent.

journal_name

Circ Res

journal_title

Circulation research

authors

Gao WD,Murray CI,Tian Y,Zhong X,DuMond JF,Shen X,Stanley BA,Foster DB,Wink DA,King SB,Van Eyk JE,Paolocci N

doi

10.1161/CIRCRESAHA.112.270827

subject

Has Abstract

pub_date

2012-09-28 00:00:00

pages

1002-11

issue

eissn

0009-7330

issn

1524-4571

pii

CIRCRESAHA.112.270827

journal_volume

111

pub_type

杂志文章

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Nitroxyl-mediated disulfide bond formation between cardiac myofilament cysteines enhances contractile function.