Retinitis Pigmentosa (RP) is one of the most frequent causes of hereditary blindness in the United States, affecting approximately 1 in every 3000 individuals. There is currently no treatment available for this disease. The broad, long term objectives of this study are to develop a therapy for RP. Some forms of RP in humans, dogs and mice (rd) are caused by mutations in the beta subunit of cGMP phosphodiesterase (bPDE). In order to deliver a normal cDNA encoding bPDE to the rd retina, we have developed a novel class of safer and less-toxic adenovirus vectors termed Encapsidated Adenovirus Minichromosomes - (EAMs or 'gutted' vectors). EAMs have a 36Kb cloning capacity, allowing insertion of large upstream regulatory elements for regulated transgene expression and/or inclusion of multiple therapeutic transgene cassettes. We have used EAMs to temporarily rescue retinal degeneration in rd1 mice by approximately 10 weeks, which would otherwise be complete by 3 weeks postnatal. Our objectives are now focused on extending this short period of rescue to one that might be more therapeutically relevant to humans. EAMs bind to their target cells by attachment of the antenna-like fiber protein to the Coxsackievirus B-adenovirus Receptor (CAR). We have determined that CAR is not significantly expressed on murine and human photoreceptors which could explain the low levels of infection by EAMs and adenovirus vectors. In order to overcome this problem, we propose to modify the structure of EAMs such that they now bind cell surface sialic acid instead of CAR. Sialic acid is abundantly present on the rod cell membrane. We also propose to test adenovirus fibers recently shown to have significantly enhanced tropism for neurons. We will use these improved EAMs to deliver bPDE to the rd10 retina. We will measure therapeutic effects on photoreceptors by PDE assays, histology, electroretinograms and western analysis. Upon completion of this study, we will have constructed and tested a vector which will have potential use in a Phase 1 clinical trial for treatment of RP in humans.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY013837-03
Application #
6864415
Study Section
Special Emphasis Panel (ZRG1-VISC (01))
Program Officer
Dudley, Peter A
Project Start
2003-05-01
Project End
2006-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
3
Fiscal Year
2005
Total Cost
$261,625
Indirect Cost
Name
University of Utah
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
009095365
City
Salt Lake City
State
UT
Country
United States
Zip Code
84112
Dasari, Bhanu Chandar; Cashman, Siobhan M; Kumar-Singh, Rajendra (2017) Reducible PEG-POD/DNA Nanoparticles for Gene Transfer In Vitro and In Vivo: Application in a Mouse Model of Age-Related Macular Degeneration. Mol Ther Nucleic Acids 8:77-89
Leaderer, Derek; Cashman, Siobhan M; Kumar-Singh, Rajendra (2016) G-quartet oligonucleotide mediated delivery of proteins into photoreceptors and retinal pigment epithelium via intravitreal injection. Exp Eye Res 145:380-392
Leaderer, Derek; Cashman, Siobhan M; Kumar-Singh, Rajendra (2015) Topical application of a G-Quartet aptamer targeting nucleolin attenuates choroidal neovascularization in a model of age-related macular degeneration. Exp Eye Res 140:171-178
Leaderer, Derek; Cashman, Siobhan M; Kumar-Singh, Rajendra (2015) Adeno-associated virus mediated delivery of an engineered protein that combines the complement inhibitory properties of CD46, CD55 and CD59. J Gene Med 17:101-15
Cashman, Siobhan M; Gracias, Jessica; Adhi, Mehreen et al. (2015) Adenovirus-mediated delivery of Factor H attenuates complement C3 induced pathology in the murine retina: a potential gene therapy for age-related macular degeneration. J Gene Med 17:229-43
Birke, M T; Lipo, E; Adhi, M et al. (2014) AAV-mediated expression of human PRELP inhibits complement activation, choroidal neovascularization and deposition of membrane attack complex in mice. Gene Ther 21:507-13
Lipo, Erion; Cashman, Siobhan M; Kumar-Singh, Rajendra (2013) Aurintricarboxylic acid inhibits complement activation, membrane attack complex, and choroidal neovascularization in a model of macular degeneration. Invest Ophthalmol Vis Sci 54:7107-14
Birke, Kerstin; Lipo, Erion; Birke, Marco T et al. (2013) Topical application of PPADS inhibits complement activation and choroidal neovascularization in a model of age-related macular degeneration. PLoS One 8:e76766
Binder, Christina; Cashman, Siobhan M; Kumar-Singh, Rajendra (2013) Extended duration of transgene expression from pegylated POD nanoparticles enables attenuation of photoreceptor degeneration. PLoS One 8:e82295
Greenwald, D L; Cashman, S M; Kumar-Singh, R (2013) Mutation-independent rescue of a novel mouse model of Retinitis Pigmentosa. Gene Ther 20:425-34

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