The goal of this project is to develop a genetic therapy for autosomal dominant retinitis pigmentosa (ADRP). Retinitis pigmentosa is a type of inherited retinal degeneration caused by the death of rod photoreceptor cells. It affects about 1 person in 3500 and leads to a progressive loss of vision and ultimately blindness, usually over a period of decades. Mutations in over 30 genes lead to retinitis pigmentosa, but defects in the gene for rhodopsin, the major light-harvesting pigment of the rod cell, are the predominant cause of ADRP. These dominant mutations lead to a malfunctioning, mis-sorted, or poorly folded molecule that eventually kills the rod cell that makes it. Our underlying hypothesis is that reducing the expression of these mutated forms of rhodopsin can rescue rod photoreceptors and preserve vision. The genetic tool we will employ for this purpose is a catalytic RNA molecule or ribozyme. Small ribozymes can be engineered to sever almost any RNA in a sequence-specific manner. The instrument we use to introduce the ribozymes into retinal cells is recombinant Adeno-Associated Virus or AAV. During the current funding period, we have designed ribozymes specific for mutant rhodopsin mRNA present in transgenic rat models of ADRP. When delivered to animals bearing the P23H rhodopsin mutation, these hammerhead and hairpin ribozymes protected photoreceptors structurally and functionally for up to 8 months. In this proposal, we describe plans to extend these promising results by improving the ribozymes and the AAV vectors that deliver them; by testing the therapy in a large animal model of ADRP (transgenic pigs); by developing allele-independent ribozymes to treat a variety of rhodopsin mutations; by employing novel RNA catalysts to increase the number of potential target sites in rhodopsin mRNA; and by evaluating gene therapy in outbred mice carrying the P23H mutation. This work will be aided by non-invasive analytical techniques that permit us to monitor retinal degeneration and the efficacy of therapy in living animals. We hope that the successful completion of this project will bring us close to employing AAV-vectored ribozymes as therapy for autosomal dominant retinitis pigmentosa in human patients.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY011596-09
Application #
6899204
Study Section
Visual Sciences C Study Section (VISC)
Program Officer
Dudley, Peter A
Project Start
1997-07-01
Project End
2006-06-30
Budget Start
2005-07-01
Budget End
2006-06-30
Support Year
9
Fiscal Year
2005
Total Cost
$325,383
Indirect Cost
Name
University of Florida
Department
Genetics
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
White, D Alan; Hauswirth, William W; Kaushal, Shalesh et al. (2007) Increased sensitivity to light-induced damage in a mouse model of autosomal dominant retinal disease. Invest Ophthalmol Vis Sci 48:1942-51
Gorbatyuk, M; Justilien, V; Liu, J et al. (2007) Suppression of mouse rhodopsin expression in vivo by AAV mediated siRNA delivery. Vision Res 47:1202-8
Gorbatyuk, M; Justilien, V; Liu, J et al. (2007) Preservation of photoreceptor morphology and function in P23H rats using an allele independent ribozyme. Exp Eye Res 84:44-52
Glushakova, Lyudmyla G; Timmers, Adrian M; Issa, Tawfik M et al. (2006) Does recombinant adeno-associated virus-vectored proximal region of mouse rhodopsin promoter support only rod-type specific expression in vivo? Mol Vis 12:298-309
Nusinowitz, S; Ridder 3rd, W H; Pang, J J et al. (2006) Cortical visual function in the rd12 mouse model of Leber Congenital Amarousis (LCA) after gene replacement therapy to restore retinal function. Vision Res 46:3926-34
Glushakova, Lyudmyla G; Timmers, Adrian M; Pang, Jijing et al. (2006) Human blue-opsin promoter preferentially targets reporter gene expression to rat s-cone photoreceptors. Invest Ophthalmol Vis Sci 47:3505-13
Gorbatyuk, M S; Pang, J J; Thomas Jr, J et al. (2005) Knockdown of wild-type mouse rhodopsin using an AAV vectored ribozyme as part of an RNA replacement approach. Mol Vis 11:648-56
Liu, Jianwen; Timmers, Adrian M; Lewin, Alfred S et al. (2005) Ribozyme knockdown of the gamma-subunit of rod cGMP phosphodiesterase alters the ERG and retinal morphology in wild-type mice. Invest Ophthalmol Vis Sci 46:3836-44
Hauswirth, William W; Li, Quihong; Raisler, Brian et al. (2004) Range of retinal diseases potentially treatable by AAV-vectored gene therapy. Novartis Found Symp 255:179-88; discussion 188-94
Qi, Xiaoping; Lewin, Alfred S; Hauswirth, William W et al. (2003) Optic neuropathy induced by reductions in mitochondrial superoxide dismutase. Invest Ophthalmol Vis Sci 44:1088-96

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