Blastocyst Injection of Wild Type Embryonic Stem Cells Induces Global Corrections in Mdx Mice.. Mus musculus

Duchenne muscular dystrophy (DMD) is an incurable neuromuscular degenerative disease, caused by a mutation in the dystrophin gene. Mdx mice recapitulate DMD features. Here we show that injection of wild-type (WT) embryonic stem cells (ESCs) into mdx blastocysts produces mice with improved pathology. A small fraction of WT ESCs incorporates into the mdx mouse nonuniformly to upregulate protein levels of dystrophin in the skeletal muscle. The chimeric muscle shows reduced regeneration and restores dystrobrevin, a dystrophin-related protein, in areas with high and with low dystrophin content. WT ESC injection also normalizes the amount of fat, a tissue that does not express dystrophin. ESC injection without dystrophin does not prevent the appearance of phenotypes in the skeletal muscle or in the fat. Thus, dystrophin supplied by the ESCs reverses disease in mdx mice globally. Overall design: 3-week old mdx (C57BL/10ScSn-Dmdmdx/J, Jax labs) females were superovulated and mated with mdx males (Jax labs). Blastocysts were collected at 3.5 days afer mating, injected with 15 WT or mdx R26 ES cells. Injected blastocysts were then transferred into the uteri of pseudopregnant females and allowed to develop to term. Skeletal muscle from 4 month old chimeric male mice was collected, RNA was isolated and microarray analysis were performed.