Human iPS Cells Derived Skeletal Muscle Progenitor Cells Promote Myoangiogenesis and Restore Dystrophin in Duchenne Muscular Dystrophic Mice

Background and ObjectiveDuchenne muscular dystrophy (DMD) is caused by mutations of the gene that encodes the protein dystrophin. Loss of dystrophin leads to severe and progressive muscle-wasting in both skeletal and heart muscles. Human induced pluripotent stem cells (hiPSCs) and their derivatives offer important opportunities to treat a number of diseases. Here, we investigated whether givinostat, a histone deacetylase inhibitor (HDACi), could reprogram hiPSCs into muscle progenitor cells (MPC) for DMD treatment. Methods and ResultsMPC generated by CHIR99021 and givinostat (Givi) small molecules from multiple hiPSCs expressed myogenic makers (Pax7, desmin) and were differentiated into myotubes expressing MF20 upon culture in specific differentiation medium. These MPC exhibited superior proliferation and migration capacity determined by CCK-8, colony and migration assays compared to control-MPC generated by CHIR99021 and fibroblast growth factor (FGF). Upon transplantation in hind limb of Mdx/SCID mice with cardiotoxin (CTX) induced injury, these MPC showed higher engraftment and restoration of dystrophin than treatment with control-MPC and human myoblasts. In addition, treated muscle with these MPC showed significantly limited infiltration of inflammatory cells and reduced muscle necrosis and fibrosis. A number of these cells were engrafted under basal lamina expressing Pax7, which were capable of generating new muscle fibers after additional injury. Extracellular vesicles released from these cells promoted angiogenesis after reinjury. ConclusionWe successfully generated integration free MPC from multiple hiPS cell lines using CHIR99021 and Givi. Givinostat induced MPC showed marked and impressive regenerative capabilities and restored dystrophin in injured tibialis muscle compared to control MPC. Additionally, MPC generated by Givi also seeded the stem cell pool in the treated muscle. It is concluded that hiPSCs pharmacologically reprogrammed into MPC with a small molecule, Givi with anti-oxidative, anti-inflammatory and muscle gene promoting properties might be an effective cellular source for treatment of muscle injury and restoration of dystrophin in DMD.