Exploration of muscle from GRMD dogs tranplanted with MuStem cells using “omics” approaches

Duchenne Muscular Dystrophy (DMD), the most common form of inherited neuromuscular disorder, is caused by mutations in the dystrophin gene leading to the protein lack. Membrane disorganization and subsequent alterations in signaling pathways and energy metabolism play important roles in muscle fibre necrosis. Systemic delivery of MuStem cells, skeletal muscle-resident stem cells isolated in healthy dog, generate a remodeling of muscle tissue and gives rise to striking clinical benefits in Golden Retriever Muscular Dystrophy (GRMD) dog. To pursue investigation of the consequences on the skeletal muscle tissue 6 months after cell transplantation with undedicated approach, we used here a combined analysis of transcriptomics (gene expression microarrays) and quantitative proteomics (ICPL/LC-MS/MS) (Robriquet et al., 2015). At molecular level, we determined that MuStem cell administration enhances muscle regeneration, promotes ubiquitin-mediated protein degradation in parallel with a decrease expression of genes associated with lipid homeostasis and energy metabolism. Furthermore, the proteomic approach confirmed a main impact of MuStem cell delivery on muscle regeneration, metabolism as well as homeostasis pathways. In addition, we establish that the analysis of a limited set of miRNAs in skeletal muscle clearly discriminates between immunosuppression context and MuStem cell therapyrelated effects on GRMD dogs. Overall, the combination of transcriptomics, proteomics and miRNA approaches allowed to pave the way to the understanding of MuStem cell action modalities as stimulation of muscle fibre formation. This strategy has a great potential to considerably contribute to the identification of therapeutic biomarkers of MuStem cell transplantation and thus represents an interesting tool to monitor therapeutic effects during DMD-dedicated preclinical studies