| Skeletal muscle is a complex and highly organized tissue that is necessary for locomotion, metabolism and breathing. Myogenesis, the formation of skeletal muscle, occurs during muscle development, remodeling and regeneration in the adult. Many processes are required for proper myofiber formation, including migration and adhesion. In this dissertation, we demonstrated that many chemokines and chemokine receptors are expressed by muscle cells in vitro. The large number of migratory factors expressed by muscle cells suggests a complex temporal and spatial control of muscle cell migration during myogenesis. These data also determine a specific role for CXCR4 and SDF1alpha during myogenesis. The migration of both proliferating and terminally differentiated muscle cells is regulated by CXCR4 and SDF1alpha. Also, in this dissertation, we determined that at least 13 olfactory receptors (ORs) are expressed during myogenesis. Furthermore, one specific OR, MOR23 regulates both migration and adhesion, affecting proper myogenesis. MOR23 also affects a phenomenon known as myofiber branching, where a myofiber is contiguous with several smaller myofibers. Myofiber branching is increased with multiple injuries, aging and muscular dystrophies and decreases the contractile force of the myofiber. Over-expression of MOR23 decreases the incidence of myofiber branching in regenerating muscle, suggesting potential options for treating various muscle diseases. Therefore, manipulation of either chemokines or ORs may allow for an increased efficiency of cell transplantation therapies for various muscle disorders. |
