Long-term restoration of cardiac dystrophin expression in golden retriever muscular dystrophy following rAAV6-mediated exon skipping.

Abstract

Although restoration of dystrophin expression via exon skipping in both cardiac and skeletal muscle has been successfully demonstrated in the mdx mouse, restoration of cardiac dystrophin expression in large animal models of Duchenne muscular dystrophy (DMD) has proven to be a challenge. In large animals, investigators have focused on using intravenous injection of antisense oligonucleotides (AO) to mediate exon skipping. In this study, we sought to optimize restoration of cardiac dystrophin expression in the golden retriever muscular dystrophy (GRMD) model using percutaneous transendocardial delivery of recombinant AAV6 (rAAV6) to deliver a modified U7 small nuclear RNA (snRNA) carrying antisense sequence to target the exon splicing enhancers of exons 6 and 8 and correct the disrupted reading frame. We demonstrate restoration of cardiac dystrophin expression at 13 months confirmed by reverse transcription-PCR (RT-PCR) and immunoblot as well as membrane localization by immunohistochemistry. This was accompanied by improved cardiac function as assessed by cardiac magnetic resonance imaging (MRI). Percutaneous transendocardial delivery of rAAV6 expressing a modified U7 exon skipping construct is a safe, effective method for restoration of dystrophin expression and improvement of cardiac function in the GRMD canine and may be easily translatable to human DMD patients.

• Authors: Lawrence T Bish, Meg M Sleeper, Sean C Forbes, Bingjing Wang, Caryn Reynolds, Gretchen E Singletary, Dennis Trafny, Kevin J Morine, Julio Sanmiguel, Sylvain Cecchini, Tamas Virag, Adeline Vulin, Cyriaque Beley, Janet Bogan, James M Wilson, Krista Vandenborne, Joe N Kornegay, Glenn A Walter, Robert M Kotin, Luis Garcia, H Lee Sweeney
• Journal: Molecular therapy : the journal of the American Society of Gene Therapy (Mol Ther) Vol. 20 Issue 3 Pg. 580-9 (Mar 2012) ISSN: 1525-0024 [Electronic] United States
• PMID: 22146342 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural, Research Support, Non-U.S. Gov't)

Chemical References

• Dystrophin
• RNA, Messenger

Topics

• Alternative Splicing
• Animals
• Cell Line
• Dependovirus (genetics)
• Disease Models, Animal
• Dogs
• Dystrophin (genetics, metabolism)
• Echocardiography
• Exons
• Fibrosis
• Gene Expression
• Gene Order
• Gene Transfer Techniques
• Genetic Vectors (genetics, pharmacokinetics)
• Genome, Viral
• Humans
• Magnetic Resonance Imaging
• Muscular Dystrophy, Duchenne (diagnosis, genetics, therapy)
• Myocardium (pathology)
• RNA, Messenger (metabolism)