title: MRI roadmap-guided transendocardial delivery of exon-skipping recombinant adeno-associated virus restores dystrophin expression in a canine model of Duchenne muscular dystrophy.
abstract: Duchenne muscular dystrophy (DMD) cardiomyopathy patients currently have no therapeutic options. We evaluated catheter-based transendocardial delivery of a recombinant adeno-associated virus (rAAV) expressing a small nuclear U7 RNA (U7smOPT) complementary to specific cis-acting splicing signals. Eliminating specific exons restores the open reading frame resulting in translation of truncated dystrophin protein. To test this approach in a clinically relevant DMD model, golden retriever muscular dystrophy (GRMD) dogs received serotype 6 rAAV-U7smOPT via the intracoronary or transendocardial route. Transendocardial injections were administered with an injection-tipped catheter and fluoroscopic guidance using X-ray fused with magnetic resonance imaging (XFM) roadmaps. Three months after treatment, tissues were analyzed for DNA, RNA, dystrophin protein, and histology. Whereas intracoronary delivery did not result in effective transduction, transendocardial injections, XFM guidance, enabled 30±10 non-overlapping injections per animal. Vector DNA was detectable in all samples tested and ranged from <1 to >3000 vector genome copies per cell. RNA analysis, western blot analysis, and immunohistology demonstrated extensive expression of skipped RNA and dystrophin protein in the treated myocardium. Left ventricular function remained unchanged over a 3-month follow-up. These results demonstrated that effective transendocardial delivery of rAAV-U7smOPT was achieved using XFM. This approach restores an open reading frame for dystrophin in affected dogs and has potential clinical utility.
authors.affiliation: Cardiovascular and Pulmonary Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Barbash
authors.forename: S
authors.initials: S
authors.lastname: Cecchini
authors.forename: A Z
authors.initials: AZ
authors.lastname: Faranesh
authors.forename: T
authors.initials: T
authors.lastname: Virag
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.forename: R F
authors.initials: RF
authors.lastname: Hoyt
authors.forename: J N
authors.initials: JN
authors.lastname: Kornegay
authors.forename: J R
authors.initials: JR
authors.lastname: Bogan
authors.forename: L
authors.initials: L
authors.lastname: Garcia
authors.forename: R J
authors.initials: RJ
authors.lastname: Lederman
authors.forename: R M
authors.initials: RM
authors.lastname: Kotin
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D000229:Dependovirus / Q000235:genetics*; D004195:Disease Models, Animal; D004285:Dogs; D016189:Dystrophin / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics; D005260:Female; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008969:Molecular Sequence Data; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D009206:Myocardium / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D061987:Sf9 Cells; D014161:Transduction, Genetic / Q000379:methods*
chemical_list: D016189:Dystrophin; D012342:RNA, Small Nuclear; C405487:U7 small nuclear RNA