Gene Therapy of Dominant CRX-Leber Congenital Amaurosis using Patient Stem Cell-Derived Retinal Organoids

Mutations in the photoreceptor transcription factor gene cone-rod homeobox (CRX) lead to distinct retinopathy phenotypes, including early-onset vision impairment in dominant Leber congenital amaurosis (LCA). Using induced pluripotent stem cells (iPSCs) from a patient with CRX-I138fs48 mutation, we established an in vitro model of CRX-LCA in retinal organoids that showed defective photoreceptor maturation by histology and gene profiling, with diminished expression of visual opsins. Adeno-associated virus (AAV)-mediated CRX gene augmentation therapy partially restored photoreceptor phenotype and expression of phototransduction-related genes as determined by single-cell RNA-sequencing. Retinal organoids derived from iPSCs of a second dominant CRX-LCA patient carrying K88N mutation revealed the loss of opsin expression as a common phenotype, which was alleviated by AAV-mediated augmentation of CRX. Our studies provide a proof-of-concept for developing gene therapy of dominant CRX-LCA and other CRX retinopathies. [Display omitted] •Leber congenital amaurosis caused by CRX mutations is modeled in retinal organoids•Patient iPSCs-derived organoids show impaired expression of visual opsins•AAV-mediated CRX delivery partially restores expression of phototransduction genes•Gene therapy is applicable to mutations in DNA-binding and transactivation domains In this article, Swaroop and colleagues show impaired expression of opsin visual pigments in retinal organoids derived from iPSC lines of patients with Leber congenital amaurosis, caused by dominant mutations in the photoreceptor transcription factor gene CRX. AAV-mediated CRX gene augmentation partially restores the expression of phototransduction genes, suggesting a potential therapeutic strategy.