Genetic Manipulation of Dysferlin Expression in Skeletal Muscle

Abstract

Mutations in the gene DYSF, which codes for the protein dysferlin, underlie Miyoshi myopathy and limb-girdle muscular dystrophy 2B in humans and produce a slowly progressing skeletal muscle degenerative disease in mice. Dysferlin is a Ca 2؉ -sensing, regulatory protein that is involved in membrane repair after injury. To assess the function of dysferlin in healthy and dystrophic skeletal muscle, we generated skeletal muscle-specific transgenic mice with threefold overexpression of this protein. These mice were phenotypically indistinguishable from wild-type, and more importantly, the transgene completely rescued the muscular dystrophy (MD) disease in Dysf-null A/J mice. The dysferlin transgene rescued all histopathology and macrophage infiltration in skeletal muscle of Dysf ؊/؊ A/J mice, as well as promoted the rapid recovery of muscle function after forced lengthening contractions. These results indicate that MD in A/J mice is autonomous to skeletal muscle and not initiated by any other cell type. However, overexpression of dysferlin did not improve dystrophic symptoms or membrane instability in the dystrophin-glycoprotein complex-lacking Scgd (␦-sarcoglycan) null mouse, indicating that dysferlin functionality is not a limiting factor underlying membrane repair in other models of MD. In summary, the restoration of dysferlin in skeletal muscle fibers is sufficient to rescue the MD in Dysfdeficient mice, although its mild overexpression does not appear to functionally enhance membrane repair in other models

Genetic ablation of complement C3 attenuates muscle pathology in dysferlin-deficient mice

“…Serum CK levels of the dysferlinnull/Tg4 mice were normal before or after exercise, but those of the dysferlin-null were elevated as reported before ( Figure 3D). Consistent with a recent report (42), these data suggest that the presence of dysferlin in skeletal muscle protects muscle from damage even in the presence of a dysferlin-deficient immune system. Furthermore, quantitative RT-PCR examination of the quadriceps muscles from the dysferlin-null/Tg4 mice suggests that transgenic expression of dysferlin normalized the expression of the complement factors C1qA and CFB ( Figure 3E).…”

Full‐length dysferlin expression driven by engineered human dystrophic blood derived CD133+ stem cells

“…Millay et al showed that replacement of the dysferlin gene in AJ mice completely rescued muscle pathology and fully restored muscular force [48]. The AAV vector is the most commonly used viral vector in muscle gene therapy; however, there are major technical issues associated with using AAV in therapeutic approaches, including the limited packaging size of AAV vectors, which is below the size of dysferlin mRNA.…”

Delineating the role of alterations in lipid metabolism to the pathogenesis of inherited skeletal and cardiac muscle disorders

“…A decrease in the content of PC in rmd/rmd mice skeletal muscle or alterations in the lipid composition, represented by changes in the PC/PE ratio, may lead to muscular dystrophy in this mouse model ( 10 ). This spontaneous recessive mutation in Chkb in rmd/rmd mice shares several phenotypic characteristics with the dysferlin null mouse, which is a model for limb-girdle dystrophy type 2B myopathy ( 177 ). Dysferlin is a sarcolemma-associated protein that is important in skeletal membrane repair using a Ca 2+ -dependent resealing mechanism ( 178 ).…”