Abstract
Purpose :
Non-viral gene therapy could provide a safer alternative approach to conventional viral therapy for the delivery of large cDNAs in patients affected by inherited retinal diseases. We assessed the use of non-viral S/MAR vectors to produce functional protein in patient cellular and zebrafish models of choroideremia, an X-linked chorioretinal dystrophy caused by mutations in the CHM gene encoding Rab escort protein 1 (REP1), a protein involved in prenylation and intracellular trafficking.
Methods :
S/MAR vectors were generated with human CHM coding sequence, the GFP reporter gene and ubiquitous promoters (CMV or CAG). The nanovector versions with minimal bacterial backbones were produced by Nature Technology.
Results :
GFP expression was assessed in transfected patient fibroblasts and chmru848 zebrafish micro-injected with the vector at the one-cell stage. CHM-S/MAR vectors restored REP-1 expression with a partial rescue of prenylation function in CHM patient fibroblasts. Human REP-1 expression was detected in micro-injected zebrafish at 6 days post-fertilisation. A mild but significant improvement in survival of 7.1 ±0.7 days (n=21) was observed in injected chmru848 zebrafish compared to 5.9 ±1.2 days (n=43) in un-injected (p<0.0001). GFP expression was detected in the retinal photoreceptors.
Conclusions :
S/MAR vectors have shown promise as a novel non-viral retinal gene therapy, warranting further development.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.