Allele-specific gene editing to rescue dominant CRX-associated LCA7 phenotypes in a retinal organoid model

Summary Cases of Leber congenital amaurosis caused by mutations in CRX (LCA7) exhibit an early form of the disease and show signs of significant photoreceptor dysfunction and eventual loss. To establish a translational in vitro model system to study gene-editing-based therapies, we generated LCA7 retinal organoids harboring a dominant disease-causing mutation in CRX. Our LCA7 retinal organoids develop signs of immature and dysfunctional photoreceptor cells, providing us with a reliable in vitro model to recapitulate LCA7. Furthermore, we performed a proof-of-concept study in which we utilize allele-specific CRISPR/Cas9-based gene editing to knock out mutant CRX and saw moderate rescue of photoreceptor phenotypes in our organoids. This work provides early evidence for an effective approach to treat LCA7, which can be applied more broadly to other dominant genetic diseases.
Graphical abstract
Highlights • A retinal organoid model of CRX-associated Leber congenital amaurosis was generated • LCA7 retinal organoids show impaired photoreceptor maturation and gene expression • scRNA-seq profiling revealed both rod and cone photoreceptor dysfunction • Allele-specific editing of mutant CRX promotes disease rescue in retinal organoids
LCA7 currently has no effective treatments; therefore, Dr. Lamba and colleagues generated LCA7 retinal organoids from patient-derived stem cells. The retinal organoids recapitulated LCA7 disease phenotypes, allowing for testing of an allele-specific gene editing approach. Early signs of disease rescue were achieved, providing evidence for a promising new strategy to treat LCA7 and other dominant retinal diseases.