Skeletal muscle differentiation on a chip shows human donor mesoangioblasts efficiency in restoring dystrophin in a DMD model

Restoration of the protein dystrophin on muscle membrane is the goal of many research lines aimed at curing Duchenne muscular dystrophy (DMD). Ongoing pre-clinical and clinical trials suggest that partial restoration of dystrophin might be sufficient to significantly reduce muscle damage. Different myogenic progenitors are candidates for the cell therapy of muscular dystrophies but only satellite cells and pericytes have already entered clinical experimentation. Our study aims at providing in vitro quantitative evidence of the ability of mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from DMD patients using a micro-engineered model. We designed an ad hoc experimental strategy, seeking to miniaturizing on chip the standard process of muscle regeneration, independently from variables such as inflammation and fibrosis. It is based on the co-culture, at different ratios, of human dystrophin positive myogenic progenitors and dystrophin negative myoblasts in a substrate with muscle-like physiological stiffness and cell micropatterns. Results showed that both healthy myoblasts and mesoangioblasts restore dystrophin expression in DMD myotubes. However, mesoangioblasts showed unexpected efficiency with respect to myoblasts in dystrophin production in terms of amount of protein produced (40% vs 15%) and length of the dystrophin membrane domain (210-240μm vs 40-70μm). These results show that our microscaled in vitro model of human DMD skeletal muscle validate previous in vivo pre-clinical work and may be used to predict efficacy of new methods aimed at