Repair of Retinal Degeneration following ExVivo Minicircle DNA Gene Therapy and Transplantation of Corrected Photoreceptor Progenitors.

Abstract

The authors describe retinal reconstruction and restoration of visual function in heritably blind mice missing the rhodopsin gene using a novel method of exvivo gene therapy and cell transplantation. Photoreceptor precursors with the same chromosomal genetic mutation were treated exvivo using minicircle DNA, a non-viral technique that does not present the packaging limitations of adeno-associated virus (AAV) vectors. Following transplantation, genetically modified cells reconstructed a functional retina and supported vision in blind mice harboring the same founder gene mutation. Gene delivery by minicircles showed comparable long-term efficiency to AAV in delivering the missing gene, representing the first non-viral system for robust treatment of photoreceptors. This important proof-of-concept finding provides an innovative convergence of cell and gene therapies for the treatment of hereditary neurodegenerative disease and may be applied in future studies toward exvivo correction of patient-specific cells to provide an autologous source of tissue to replace lost photoreceptors in inherited retinal blindness. This is the first report using minicircles in photoreceptor progenitors and the first to transplant corrected photoreceptor precursors to restore vision in blind animals.