Development of gene therapy for Duchenne muscular dystrophy heart disease in the MDX mouse model

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Duchenne muscular dystrophy (DMD) is a fatal genetic muscle disease with no cure. DMD results from mutations in a critical muscle protein called dystrophin. Children born with DMD suffer severe muscle wasting leading to progressive weakness and paralysis. Patients usually die of respiratory or heart failure before the age of thirty. Gene therapy raises the hope of a cure for DMD heart disease. While significant strides have been made towards therapy for skeletal muscle disease, development of heart gene therapy lags behind. The seminal questions for realization of heart gene therapy of DMD include; developing an animal model, determining dosage, finding the correct gene, developing the vehicle for gene therapy and optimizing gene delivery. This dissertation details critical advancements towards gene therapy for DMD heart disease. First, we developed an animal model of DMD heart disease in the mdx mouse. We then determined that 50% mosaic dystrophin expression was sufficient to prevent DMD heart disease in this model. Next, we established that the truncated mini-dystrophin gene was capable of ameliorating DMD heart disease in the mdx mouse through cardiac specific transgenic expression. Then, we established the adeno-associated virus (AAV) as a vehicle for DMD heart gene therapy regardless of mouse age or the route of administration. Finally, we discovered that AAV-mediated truncated dystrophin gene therapy prevented DMD heart disease in neonatal mdx mice and ameliorated heart disease in symptomatic mdx mice. This work represents significant progress towards realization of an effective therapy for DMD heart disease.