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Principal Investigator: RONALD G GREGG
Organization: UNIVERSITY OF LOUISVILLE
Fiscal Year: 2024
Award: $568,819
Funding agency: National Eye Institute
Autosomal dominant Retinitis pigmentosa (adRP) is a blinding eye disease that results in loss of rods and
eventually cone photoreceptors. A large fraction of adRP is caused by mutations in the rhodopsin (Rho) gene,
and the most common mutation in North America causes a P23H mutation in rhodopsin. Patients typically
present with mid- to late-stage disease when many rod photoreceptors already have degenerated.
We will evaluate genome editing using a meganuclease genome editing tool (Rho1-2) that is specific for the
sequence causing the P23H mutation in several preclinical animal models of P23H adRP. We will deliver AAV5-
GRK1-Rho1-2 via subretinal injection to infect photoreceptors. We will measure efficacy, the ability of Rho1-2 to
alter rod degeneration and functional decline. We will quantitatively determine Rho1-2 efficiency, the proportion
of P23H alleles with insertions/delections (indels), specificity the proportion of P23H to WT alleles with indels,
and its safety, the absence of indels in other genes throughout the human genome (off target editing).
In Pig P23H adRP models we will evaluate Rho1-2 editing efficacy because of the similarities between pigs and
humans in eye size and retinal structure and because the pig has a cone rich visual streak. We will use the same
non-invasive tools used in the clinic to measure retinal function (full field electroretinograms) and structure,
(spectral domain OCT). We will use two existing transgenic pig lines that harbor the entire P23H hRHO gene,
but differ in their time course, resulting in a fast or slow loss of rods and rod function. We will match treatment
time with the natural history of rod structural and functional decline, compare Rho1-2 editing efficacy in early-,
mid- and late-stage P23H adRP and define its temporal treatment window. In Humanized adRP mouse models
we will evaluate Rho1-2 editing efficiency and specificity because they contain WT and P23H human alleles in
the appropriate genomic context. In human retinal organoids we will evaluate Rho1-2 editing safety (off-target
cutting throughout the genome) because they contain human photoreceptors as well as the rest of the human
genome in a relevant context..
Taken together the results of our experiments will determine if Rho1-2 should move forward for eventual use in
human clinical trials and will define endpoints for those trials.
Terms: <Accounting><Affect><Alleles><Allelomorphs><Animal Euthanasia><Animal Mercy Killing><Animal Model><Animal Models and Related Studies><Animals><Behavior><Biologic Models><Biological Models><Blindness><CRISPR><CRISPR/Cas system><Canine Species><Canis familiaris><Cell Body><Cells><Clinic><Clinical><Clinical Trials><Clustered Regularly Interspaced Short Palindromic Repeats><Cone><Cone Photoreceptors><DNA Therapy><Development><Disease><Disorder><Dogs><Dogs Mammals><Double Strand Break Repair><Electroretinography><Engineering><Eye><Eye diseases><Eyeball><Family suidae><Frequencies><GRK1><GRK1 gene><GUIDE-seq><Gene Alteration><Gene Expression><Gene Mutation><Gene Transfer Clinical><Genes><Genetic Alteration><Genetic Change><Genetic Intervention><Genetic defect><Genome><Genome-wide Unbiased Identification of DSBs Enabled by sequencing><Genomics><Goals><Homing><Human><Human Genome><Intervention><Intervention Strategies><Investigators><Measures><Methodology><Mice><Mice Mammals><Modality><Model System><Modeling><Modern Man><Morphology><Murine><Mus><Mutate><Mutation><NHEJ><Natural History><Night Blindness><Non-Homologous End Joining><Non-homologous DNA End Joining><Nonhomologous DNA End Joining><Nonhomologous End Joining><North America><Nyctalopia><Organoids><Orphan Disease><Outcome><Patient Selection><Patients><Photoreceptor Cell><Photoreceptors><Photosensitive Cell><Pigmentary Retinopathy><Pigs><Pre-Clinical Model><Preclinical Models><Proteins><RHOK><Rare Diseases><Rare Disorder><Research Personnel><Researchers><Rest><Retina><Retinal Cone><Retinal Degeneration><Retinal Diseases><Retinal Disorder><Retinitis Pigmentosa><Rhodopsin><Rod><Rod Photoreceptors><Rods and Cones><Safety><Selection Criteria><Site><Specificity><Structure><Suidae><Swine><Tapetoretinal Degeneration><Technology><Therapeutic><Time><Transgenic Organisms><Vertebrate Photoreceptors><Viral Packaging><Virus Packagings><Visual><Visual Purple><Visual Receptor><ZNFs><Zn-finger nuclease><alternative treatment><autosome><canine><cone cell><customized therapy><customized treatment><decline in function><decline in functional status><deep sequencing><degenerative retina diseases><determine efficacy><developmental><domestic dog><efficacy analysis><efficacy assessment><efficacy determination><efficacy evaluation><efficacy examination><efficacy testing><electroretinogram><endonuclease><evaluate efficacy><examine efficacy><experiment><experimental research><experimental study><experiments><eye disorder><functional decline><functional status decline><gene editing platform><gene editing system><gene editing technology><gene editing tools><gene repair therapy><gene therapy><gene-based therapy><gene-editing toolkit><genetic therapy><genome editing><genome mutation><genomic editing><genomic therapy><human model><human whole genome><humanized mice><humanized mouse><in silico><indel><individualized medicine><individualized patient treatment><individualized therapeutic strategy><individualized therapy><individualized treatment><insertion-deletion><insertion-deletion mutation><insertion/deletion><insertion/deletion mutation><interest><interventional strategy><model of animal><model of human><mouse model><murine model><mutant><neglect><non-human primate><nonhuman primate><nuclease><ocular disease><ocular disorder><off-target site><ophthalmopathy><optimal therapies><optimal treatments><orphan disorder><patient specific therapies><patient specific treatment><pig model><piglet model><porcine><porcine model><pre-clinical><pre-clinical evaluation><preclinical><preclinical evaluation><retina degeneration><retina disease><retina disorder><retinal degenerative><retinal degenerative diseases><retinal rods><retinopathy><rhodopsin kinase><rod and cone dystrophy><rod cell><rod-cone dystrophy><safety assessment><subretinal injection><suid><swine model><tailored medical treatment><tailored therapy><tailored treatment><timeline><tool><transgenic><unique treatment><vision loss><visual loss><zinc finger nuclease><zinc finger nucleases>