667. Lentiviral Gene Transfer of RPE65 cDNA in Knock-Out Mouse Models of Leber Congenital Amaurosis

Abstract

Gene transfer is a promising approach for single gene defect in several retinal degeneration disorders. Among them, 10-15% of Leber congenital amaurosis (LCA) cases, a severe retinal degeneration of early childhood, bear a mutation in the RPE65 gene, the function of which is essential for the visual cycle. AAV-mediated gene therapy was already described in dog and mouse models of LCA using CMV or composite promoters. These studies have shown that RPE65 gene transfer is able to restore vision, at least partially. We evaluated the efficiency of gene transfer in rodent models of LCA using a lentiviral vector containing a RPE65 promoter fragment driving the expression of the therapeutic RPE65 cDNA. In addition, to explore the effect of RPE65 restoration on the different photoreceptor subtypes, we studied its effect in two models of LCA, the RPE65 and the RPE65/GNAT1 knock-out mice. In the latter, invalidation of the rod transducin |[aacute]|-subunit (GNAT1) gene prevent the functioning of rod photoreceptors thus allowing to better distinguish the potential cone response.