1. Disease modeling and pharmacological rescue of autosomal dominant retinitis pigmentosa associated with RHO copy number variation.
- Author
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Kandoi S, Martinez C, Chen KX, Mehine M, Reddy LVK, Mansfield BC, Duncan JL, and Lamba DA
- Subjects
- Aged, Humans, Male, Organoids metabolism, Organoids drug effects, DNA Copy Number Variations, Retinitis Pigmentosa genetics, Retinitis Pigmentosa metabolism, Rhodopsin genetics, Rhodopsin metabolism
- Abstract
Retinitis pigmentosa (RP), a heterogenous group of inherited retinal disorder, causes slow progressive vision loss with no effective treatments available. Mutations in the rhodopsin gene ( RHO ) account for ~25% cases of autosomal dominant RP (adRP). In this study, we describe the disease characteristics of the first-ever reported mono-allelic copy number variation (CNV) in RHO as a novel cause of adRP. We (a) show advanced retinal degeneration in a male patient (68 years of age) harboring four transcriptionally active intact copies of rhodopsin, (b) recapitulated the clinical phenotypes using retinal organoids, and (c) assessed the utilization of a small molecule, Photoregulin3 (PR3), as a clinically viable strategy to target and modify disease progression in RP patients associated with RHO -CNV. Patient retinal organoids showed photoreceptors dysgenesis, with rod photoreceptors displaying stunted outer segments with occasional elongated cilia-like projections (microscopy); increased RHO mRNA expression (quantitative real-time PCR [qRT-PCR] and bulk RNA sequencing); and elevated levels and mislocalization of rhodopsin protein (RHO) within the cell body of rod photoreceptors (western blotting and immunohistochemistry) over the extended (300 days) culture time period when compared against control organoids. Lastly, we utilized PR3 to target NR2E3 , an upstream regulator of RHO , to alter RHO expression and observed a partial rescue of RHO protein localization from the cell body to the inner/outer segments of rod photoreceptors in patient organoids. These results provide a proof-of-principle for personalized medicine and suggest that RHO expression requires precise control. Taken together, this study supports the clinical data indicating that RHO-CNV associated adRPdevelops as a result of protein overexpression, thereby overloading the photoreceptor post-translational modification machinery., Competing Interests: SK, CM, KC, MM, LR, BM No competing interests declared, JD Dr. Duncan was a consultant for ConeSight, DTx Therapeutics, Editas,Eloxx, Eyevensys, Gyroscope, Helios,Nacuity, ProQR, PYC Therapeutics,Replay Therapeutics, Spark,SparingVision, Vedere Bio until 01/2022. These were unrelated to the manuscript, DL is affiliated with Genentech. The author has no financial interests to declare, (© 2023, Kandoi et al.)
- Published
- 2024
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