A genome editing approach to prevent retinal degeneration has been demonstrated in mice. This approach, published in Nature Communications this week, makes use of the CRISPR/Cas9 gene therapy system, and may be suitable for a wide range of underlying genetic defects in retinitis pigmentosa, a leading cause of blindness.
Retinitis pigmentosa is characterised by degeneration of the retina, which includes both rod cells and cone cells. It can be caused by mutations in more than 60 genes, making it difficult to develop targeted treatments to correct each specific gene. The mutations that cause retinitis pigmentosa lead to death of rods and this in turn causes the death of cones, leading to loss of vision.
Rather than fixing the disease causing mutations, Zhijian Wu and colleagues test an approach to preserve cone cells. They use CRISPR/Cas9 to disrupt a gene that determines rod cell identity, inducing rod cells to adopt cone features, making them tolerate deleterious effects of disease-causing mutations. The treatment was shown to prevent retinal degeneration and improve vision in three mouse models (a total of 30 mice) of retinal degeneration. These results suggest that this approach may be suitable as a treatment of retinal degenerative diseases, and may be applicable independently of the underlying mutations.