Cardiac-Specific Expression of ?H2-R15 Mini-Dystrophin Normalized All Electrocardiogram Abnormalities and the End-Diastolic Volume in a 23-Month-Old Mouse Model of Duchenne Dilated Cardiomyopathy.
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ABSTRACT: Heart disease is a major health threat for Duchenne/Becker muscular dystrophy patients and carriers. Expression of a 6-8?kb mini-dystrophin gene in the heart holds promise to change the disease course dramatically. However, the mini-dystrophin gene cannot be easily studied with adeno-associated virus (AAV) gene delivery because the size of the minigene exceeds AAV packaging capacity. Cardiac protection of the ?H2-R19 minigene was previously studied using the cardiac-specific transgenic approach. Although this minigene fully normalized skeletal muscle force, it only partially corrected electrocardiogram and heart hemodynamics in dystrophin-null mdx mice that had moderate cardiomyopathy. This study evaluated the ?H2-R15 minigene using the same transgenic approach in mdx mice that had more severe cardiomyopathy. In contrast to the ?H2-R19 minigene, the ?H2-R15 minigene carries dystrophin spectrin-like repeats 16 to 19 (R16-19), a region that has been suggested to protect the heart in clinical studies. Cardiac expression of the ?H2-R15 minigene normalized all aberrant electrocardiogram changes and improved hemodynamics. Importantly, it corrected the end-diastolic volume, an important diastolic parameter not rescued by ?H2-R19 mini-dystrophin. It is concluded that that ?H2-R15 mini-dystrophin is a superior candidate gene for heart protection. This finding has important implications in the design of the mini/micro-dystrophin gene for Duchenne cardiomyopathy therapy.
SUBMITTER: Wasala NB
PROVIDER: S-EPMC6066193 | biostudies-literature | 2018 Jul
REPOSITORIES: biostudies-literature
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