Translational Studies of GALGT2 Gene Therapy for Duchenne Muscular Dystrophy.

摘要

The purpose of this proposal is to perform translational studies in support of developing GALGT2 gene therapy for use in Duchenne Muscular dystrophy patients. In year 1, we have completed the tasks of dosing almost all cohorts of experimental animals to be used in Years 1 and 2 (Wild type or WT, Cmah-/-, mdx and Cmah-/-mdx) via intramuscular injection with the two therapeutic gene therapy vectors to be tested (AAVrh74.MCK.GALGT2 and AAVrh74.MHCK7.GALGT2). We have several major findings from this work, and several experimental problems that need to be resolved. By analyzing functional gene expression in AAV dose response curves, we find that Cmah-/- animals have more expression from rAAVrh74.(MCK or MHCK7).GALGT2 injection at the same dose compared to WT. Likewise, Cmah-/-mdx show higher expression than mdx. These data demonstrate that the human GALGT2 gene may show greater potency in DMD patients than its does in mdx mice due to the altered sialic acid repertoire that exists in humans. Similarly, we find that use of the MHCK7 promoter yielded higher GALGT2 expression at the same AAV dose compared to the MCK promoter. This data suggests that use of the MHCK7 promoter in gene therapy vectors will be more potent in DMD patients. Experimental issues yet to be resolved include understanding the timing of gene overexpression needed to maximize changes in functional measures.