UC Irvine

Inherited retinal degenerations (IRDs), leading to vision loss, are caused by mutations in genes or regulatory elements critical for retinal structure and function. Despite extensive research, effective IRD therapy is still lacking due to the large pool of genes involved and the fact that multiple mutations in a single gene can cause different phenotypes, requiring distinct treatments. Recent genome-editing advances, like CRISPR-Cas9, base editors (BE), and prime editors (PE), have shown feasibility by correcting mutated genes in vitro, but significant obstacles remain for translating these approaches to clinical applications. A key challenge is efficient delivery of these editors due to their large size and negatively charged guide RNA. Thus, advancement of BE and PE into the eye and for other genetic diseases requires novel delivery mechanisms. In this work, we demonstrated the correction of blindness-causing mutations in the mouse equivalents of RHO, MFRP, and RPE65 following subretinal injection. Efficient editing was observed, which restored protein expression and physiological function within the eye. This was achieved through the development of new in vivo delivery modalities of BE and PE, including split adeno-associated viruses, two types of virus-like particles, and lipid nanoparticles. The transient, safe, and efficient delivery of BE and PE is thus poised to create new solutions for the treatment of IRDs and other genetic disorders.