Exon Skipping in CD133+ Cells from Blood and Muscle
Deficiency of dysferlin at the sarcolemma causes two main phenotypes of autosomal recessive muscular dystrophies: Miyoshi myopathy (MM) and Limb-Girdle Muscular Dystrophy type 2B (LGMD2B). We will combine the exon skipping approach with an autologous cell therapy approach to circumvent some crucial problems with in vivo delivery of oligonucleotides, including high viral titres and the immune response against AAV vectors needed to spread specific antisense oligonucleotides in dystrophic muscles (Chirmule et al, 2000; Gregorevic et al, 2004; Manning et al, 1998; Riviere et al, 2006). We previously investigated a combined stem cell and exon skipping approach in Duchenne muscular dystrophy (DMD), an X-linked inherited pathology caused by mutations in the gene for dystrophin. We isolated DMD myogenic progenitors from the blood and muscle of mdx mice based on their expression of CD133 antigen and evaluated their muscle regeneration potentiality after in vitro exon skipping treatment. The skipped DMD cells were able to fuse with scid/mdx mice muscle fibers and largely expressed human dystrophin (Benchaouir et al, submitted). These data open the possibility that transplantation of autologous engineered blood or muscle CD133+ stem cells could represent a future treatment for other muscular dystrophies, like LGMD2B and MM.