DNA-Mediated Gene Therapy for Dysferlinopathy
During the first year of the project, we completed gene therapy studies involving vascular delivery of plasmids encoding dysferlin or dysferlin plus follistatin in an immune-deficient BlAJ/NRG mouse model. We observed strong dysferlin expression that was distributed throughout the hind limb muscles, as judged by western blots and immunohistochemistry. Furthermore, a statistically significant decline in Evan’s blue dye permeability was seen in the hamstring muscle when dysferlin was co-delivered with follistatin in a 12-week study in older mice. To build on these successful results, in the second year of the project, we will create new expression plasmids in which dysferlin or dysferlin + follistatin are driven by the muscle-specific CK6 promoter, to compare with the CAG-driven expression used in the previous studies. Immune competent BlA/J mice will be used, and we will also examine the effects of genomic integration of the therapeutic plasmids mediated by phiC31 integrase. Longer studies starting with younger mice will be performed, evaluating dysferlin levels and distribution in hind limb muscles and seeking improvements in muscle histology, including reduced permeability to Evan’s blue dye.