Abstracts

Skeletal muscle function can be severely compromised by injury and disease, leading to decreased quality of life. Progressive muscle wasting due to genetic disorders results in myofiber necrosis and ultimate loss of muscle function. In case of muscular dystrophies, lack of functional regenerative machinery results in replacement of muscle fibers with connective and adipose tissue. Despite extensive efforts to develop cell-based therapies, several major limitations, such as limited expansion capacity of cells, immune rejection, and lack of cell viability hinders the therapeutic potential of transplanted cells. Previous studies and clinical trials have studied the efficacy of cell therapy for muscle regeneration and have faced disappointing results, including low levels of engraftment within host tissue and insignificant improvements in muscle function. These outcomes can be attributed to the intrinsic limitation of muscle tissue to engraftment of transplanted cells. This doctorate dissertation worked towards developing a cell-based therapy with a focus on induced pluripotent stem cells (iPSCs) to address muscular injuries. Specifically, we developed an approach for matrix-mediated myogenic differentiation of hiPSC-derived muscle progenitor cells (MPCs) using a synthetic mimic of heparin incorporated in a gelatin-based hydrogel. We show that using this approach large quantity of progenitor cells can be derived in vitro and used for in vivo applications. The engraftment potential of such progenitor cells is tested in immunocompromised mdx mice. Furthermore, we investigate the various stages of myogenic differentiation and identified different sub-populations present in culture. We were able to show that transplantation of a specific stage of myogenic differentiation is best suited for treatment of Duchenne Muscular Dystrophy modeled in mdx mice. The results described in this thesis provide a proof-of-principle that derivation of myogenic progenitor cells without genetic modifications can be achieved using a simple monolayer culture system by taking advantage of biomaterials. We further demonstrate the significance of the extent of in vitro myogenic maturation for successful cell transplantation.