Modeling PRPF31 retinitis pigmentosa using iPSC-derived retinal organoids and retinal pigmented epithelium and rescue by gene augmentation strategy

Mutations in the ubiquitously expressed pre-mRNA processing factor (PRPF) 31, one of the most common cause of dominant form of Retinitis Pigmentosa (RP), lead to retina-specific phenotype. It is uncertain which retinal cell types are affected and animal models do not clearly present the RP phenotype observed in PRPF31 patients. Retinal organoids and retinal pigmented epithelial (RPE) cells derived from human induced pluripotent stem cells (iPSCs) provide potential opportunities for studying human PRPF31-related RP. We demonstrated that RPE cells carrying PRPF31 mutations present important morphological and functional changes and that PRPF31-mutated retinal organoids recapitulate the human RP phenotype, with a rod photoreceptor cell death followed by a loss of cones. The low level of PRPF31 expression may explain the defective phenotypes of PRPF31-mutated RPE and photoreceptor cells, which were not observed in cells derived from asymptomatic patients or after correction of the pathogenic mutation by CRISPR/Cas9. Transcriptome profiles revealed differentially expressed and mis-spliced genes belonging to pathways in line with the observed defective phenotypes. The rescue of RPE and photoreceptor defective phenotypes by PRPF31 gene augmentation, provide the proof of concept for future therapeutic strategies. Overall design: Comparative gene expression profiling analysis of RNA-seq data from retinal organoids and retinal pigmented epithelial (RPE) cells derived from patient induced pluripotent stem cells (iPSCs). Human iPSCs were derived from control and familly members carrying PRPF31 mutations who are asymptomatic or symprtomatic with photoreceptor degeneration.