Abstract
Aberrant intracellular Ca2+ regulation is believed to contribute to the development of cardiomyopathy in Duchenne muscular dystrophy. Here, we tested whether inhibition of protein kinase A (PKA) phosphorylation of ryanodine receptor type 2 (RyR2) prevents dystrophic cardiomyopathy by reducing SR Ca2+ leak in the mdx mouse model of Duchenne muscular dystrophy. mdx mice were crossed with RyR2-S2808A mice, in which PKA phosphorylation site S2808 on RyR2 is inactivated by alanine substitution. Compared with mdx mice that developed age-dependent heart failure, mdx-S2808A mice exhibited improved fractional shortening and reduced cardiac dilation. Whereas application of isoproterenol severely depressed cardiac contractility and caused 95% mortality in mdx mice, contractility was preserved with only 19% mortality in mdx-S2808A mice. SR Ca2+ leak was greater in ventricular myocytes from mdx than mdx-S2808A mice. Myocytes from mdx mice had a higher incidence of isoproterenol-induced diastolic Ca2+ release events than myocytes from mdx-S2808A mice. Thus, inhibition of PKA phosphorylation of RyR2 reduced SR Ca2+ leak and attenuated cardiomyopathy in mdx mice, suggesting that enhanced PKA phosphorylation of RyR2 at S2808 contributes to abnormal Ca 2+ homeostasis associated with dystrophic cardiomyopathy.
Original language | English (US) |
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Pages (from-to) | 13165-13170 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 107 |
Issue number | 29 |
DOIs | |
State | Published - Jul 20 2010 |
Keywords
- Calcium
- Cardiomyopathy
- Dystrophin
- Ryanodine receptor
- Sarcoplasmic reticulum
ASJC Scopus subject areas
- General