Ex vivo gene therapy using human muscle stem cells and bacterial nanocellulose as a new culture strategy

Abstract

Muscular dystrophies (MD) are a group of untreatable degenerative disorders of inherited origin, characterized by progressive muscle wasting and short life expectancy. Cell-based therapy holds the promise to repopulated and restore the dystrophic muscle after allogeneic or autologous transplantation. Muscle satellite cells (MuSC) are responsible of muscle regeneration and represent an optimal candidate for cell-therapies, although there are limitations as the loss of their stemness during in vitro amplification. Cell-based strategies can be combined with gene editing technologies, such us CRISPR/Cas9, for autologous transplantation of corrected cells. The establishment of optimal gene correction strategies, as well as new culture conditions that preserve the regenerative potential of MuSC have been extensively investigated to improving cell-based treatments. Here, I first developed a CRISPR/Cas9-based ex vivo gene editing method in patient-derived MuSC to repair a mutation in the dysferlin gene (DYSF) that is known to cause limb girdle muscular dystrophy type 2B. Then, I characterized bacterial nanocellulose (BNC) as an alternative substrate for control human MuSC. Results show that BNC induces a slow-dividing state of the cells, avoiding extensive propagation and preserving them for weeks without undergoing terminal differentiation or senescence. Lastly, I proved that CRISPR/Cas9-based gene editing is also functional in control human MuSC on BNC using NCAM1 knockout as readout strategy. Therefore, BNC is a suitable in vitro method for testing genetic manipulation in slowly-dividing primary cells.