title: β-Sarcoglycan gene transfer decreases fibrosis and restores force in LGMD2E mice.
abstract: Limb-girdle muscular dystrophy type 2E (LGMD2E) results from mutations in the β-sarcoglycan (SGCB) gene causing loss of functional protein and concomitant loss of dystrophin-associated proteins. The disease phenotype is characterized by muscle weakness and wasting, and dystrophic features including muscle fiber necrosis, inflammation and fibrosis. The Sgcb-null mouse recapitulates the clinical phenotype with significant endomysial fibrosis providing a relevant model to test whether gene replacement will be efficacious. We directly addressed this question using a codon optimized human β-sarcoglycan gene (hSGCB) driven by a muscle-specific tMCK promoter (scAAVrh74.tMCK.hSGCB). Following isolated limb delivery (5 × 10(11) vector genome (vg)), 91.2% of muscle fibers in the lower limb expressed β-sarcoglycan, restoring assembly of the sarcoglycan complex and protecting the membrane from Evans blue dye leakage. Histological outcomes were significantly improved including decreased central nucleation, normalization of muscle fiber size, decreased macrophages and inflammatory mononuclear cells, and an average of a 43% reduction in collagen deposition in treated muscle compared with untreated muscle at end point. These measures correlated with improvement of tetanic force and resistance to eccentric contraction. In 6-month-old mice, as indicated by collagen staining, scAAVrh74.tMCK.hSGCB treatment reduced fibrosis by 42%. This study demonstrates the potential for gene replacement to reverse debilitating fibrosis, typical of muscular dystrophy, thereby providing compelling evidence for movement to clinical gene replacement for LGMD2E.
authors.affiliation: Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.|Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Pozsgai
authors.affiliation: Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Griffin
authors.affiliation: Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.|Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: Heller
authors.affiliation: Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.|Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.|Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA.|Department of Pediatrics and Neurology, The Ohio State University, Columbus, OH, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Mendell
authors.affiliation: Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.|Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.|Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA.|Department of Pediatrics and Neurology, The Ohio State University, Columbus, OH, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Rodino-Klapac
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005355:Fibrosis / Q000235:genetics / Q000628:therapy; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000503:physiopathology; D009136:Muscular Dystrophies / Q000235:genetics / Q000628:therapy; D009154:Mutation; D058088:Sarcoglycanopathies / Q000235:genetics / Q000628:therapy*; D049031:Sarcoglycans / Q000235:genetics* / Q000378:metabolism
chemical_list: C483098:SGCB protein, human; D049031:Sarcoglycans