Oxidized CaMKII (Ca2+/Calmodulin-Dependent Protein Kinase II) Is Essential for Ventricular Arrhythmia in a Mouse Model of Duchenne Muscular Dystrophy

Qiongling Wang; Ann P Quick; Shuyi Cao; Julia Reynolds; David Y Chiang; David Beavers; Na Li; Guoliang Wang; George G Rodney; Mark E Anderson; Xander H T Wehrens

doi:10.1161/CIRCEP.117.005682

Oxidized CaMKII (Ca²⁺/Calmodulin-Dependent Protein Kinase II) Is Essential for Ventricular Arrhythmia in a Mouse Model of Duchenne Muscular Dystrophy

Circ Arrhythm Electrophysiol. 2018 Apr;11(4):e005682. doi: 10.1161/CIRCEP.117.005682.

Authors

Affiliations

¹ Department of Molecular Physiology and Biophysics (Q.W., A.P.Q., S.C., J.R., D.Y.C., D.B., N.L., G.W., G.G.R., X.H.T.W.), Department of Medicine (Cardiology) (N.L., X.H.T.W.), Department of Pediatrics (Cardiology) (X.H.T.W.), and Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX. Brigham and Women's Hospital, Harvard Medical School, Boston, MA (D.Y.C.). Duke University School of Medicine, Durham, NC (D.B.). Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD (M.E.A.).
² Department of Molecular Physiology and Biophysics (Q.W., A.P.Q., S.C., J.R., D.Y.C., D.B., N.L., G.W., G.G.R., X.H.T.W.), Department of Medicine (Cardiology) (N.L., X.H.T.W.), Department of Pediatrics (Cardiology) (X.H.T.W.), and Center for Space Medicine (X.H.T.W.), Baylor College of Medicine, Houston, TX. Brigham and Women's Hospital, Harvard Medical School, Boston, MA (D.Y.C.). Duke University School of Medicine, Durham, NC (D.B.). Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD (M.E.A.). wehrens@bcm.edu.

Abstract

Background: Duchenne muscular dystrophy patients are prone to ventricular arrhythmias, which may be caused by abnormal calcium (Ca²⁺) homeostasis and elevated reactive oxygen species. CaMKII (Ca²⁺/calmodulin-dependent protein kinase II) is vital for normal Ca²⁺ homeostasis, but excessive CaMKII activity contributes to abnormal Ca²⁺ homeostasis and arrhythmias in cardiomyocytes. Reactive oxygen species induce CaMKII to become autonomously active. We hypothesized that genetic inhibition of CaMKII oxidation (ox-CaMKII) in a mouse model of Duchenne muscular dystrophy can alleviate abnormal Ca²⁺ homeostasis, thus, preventing ventricular arrhythmia. The objective of this study was to test if selective loss of ox-CaMKII affects ventricular arrhythmias in the mdx mouse model of Duchenne muscular dystrophy.

Methods and results: 5-(6)-Chloromethyl-2,7-dichlorodihydrofluorescein diacetate staining revealed increased reactive oxygen species production in ventricular myocytes isolated from mdx mice, which coincides with elevated ventricular ox-CaMKII demonstrated by Western blotting. Genetic inhibition of ox-CaMKII by knockin replacement of the regulatory domain methionines with valines (MM-VV [CaMKII M281/282V]) prevented ventricular tachycardia in mdx mice. Confocal calcium imaging of ventricular myocytes isolated from mdx:MM-VV mice revealed normalization of intracellular Ca²⁺ release events compared with cardiomyocytes from mdx mice. Abnormal action potentials assessed by optical mapping in mdx mice were also alleviated by genetic inhibition of ox-CaMKII. Knockout of the NADPH oxidase regulatory subunit p47 ^phox normalized elevated ox-CaMKII, repaired intracellular Ca²⁺ homeostasis, and rescued inducible ventricular arrhythmias in mdx mice.

Conclusions: Inhibition of reactive oxygen species or ox-CaMKII protects against proarrhythmic intracellular Ca²⁺ handling and prevents ventricular arrhythmia in a mouse model of Duchenne muscular dystrophy.

Keywords: Duchenne muscular dystrophy; action potential; arrhythmia; calcium/calmodulin-dependent protein kinase II; reactive oxygen species.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Action Potentials
Animals
Arrhythmias, Cardiac / enzymology
Arrhythmias, Cardiac / etiology*
Arrhythmias, Cardiac / physiopathology
Arrhythmias, Cardiac / prevention & control
Calcium / metabolism
Calcium Signaling
Calcium-Calmodulin-Dependent Protein Kinase Type 2 / genetics
Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism*
Disease Models, Animal
Heart Rate
Heart Ventricles / enzymology*
Heart Ventricles / physiopathology
Mice, Inbred mdx
Mice, Transgenic
Muscular Dystrophy, Duchenne / complications*
Muscular Dystrophy, Duchenne / enzymology
Muscular Dystrophy, Duchenne / physiopathology
NADPH Oxidase 2 / metabolism
Oxidation-Reduction
Oxidative Stress
Reactive Oxygen Species / metabolism

Substances

Reactive Oxygen Species
Cybb protein, mouse
NADPH Oxidase 2
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Calcium

Abstract

Publication types

MeSH terms

Substances

Grants and funding