title: Targeting the activin type IIB receptor to improve muscle mass and function in the mdx mouse model of Duchenne muscular dystrophy.
abstract: The activin receptor type IIB (ActRIIB) is a transmembrane receptor for transforming growth factor-β superfamily members, including myostatin, that are involved in the negative regulation of skeletal muscle mass. We tested the translational hypothesis that blocking ligand binding to ActRIIB for 12 weeks would stimulate skeletal muscle growth and improve muscle function in the mdx mouse. ActRIIB was targeted using a novel inhibitor comprised of the extracellular portion of the ActRIIB fused to the Fc portion of murine IgG (sActRIIB), at concentrations of 1.0 and 10.0 mg/kg(-1) body weight. After 12 weeks of treatment, the 10.0 mg/kg(-1) dose caused a 27% increase in body weight with a concomitant 33% increase in lean muscle mass. Absolute force production of the extensor digitorum longus muscle ex vivo was higher in mice after treatment with either dose of sActRIIB, and the specific force was significantly higher after the lower dose (1.0 mg/kg(-1)), indicating functional improvement in the muscle. Circulating creatine kinase levels were significantly lower in mice treated with sActRIIB, compared with control mice. These data show that targeting the ActRIIB improves skeletal muscle mass and functional strength in the mdx mouse model of DMD, providing a therapeutic rationale for use of this molecule in treating skeletal myopathies.
authors.affiliation: Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Emidio E
authors.initials: EE
authors.lastname: Pistilli
authors.forename: Sasha
authors.initials: S
authors.lastname: Bogdanovich
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Goncalves
authors.forename: Rexford S
authors.initials: RS
authors.lastname: Ahima
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lachey
authors.forename: Jasbir
authors.initials: J
authors.lastname: Seehra
authors.forename: Tejvir
authors.initials: T
authors.lastname: Khurana
mesh_terms: D030301:Activin Receptors, Type II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D001835:Body Weight; D003402:Creatine Kinase / Q000097:blood; D006909:Hydroxyproline / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology*; D009137:Muscular Dystrophy, Animal / Q000097:blood / Q000473:pathology / Q000503:physiopathology*; D009929:Organ Size; D020127:Recovery of Function / Q000502:physiology*
chemical_list: D030301:Activin Receptors, Type II; C425584:activin receptor type II-B; D003402:Creatine Kinase; D006909:Hydroxyproline