Binocular Benefit Following Monocular Subretinal AAV Injection in a Mouse Model of Autosomal Dominant Retinitis Pigmentosa (adRP)

Autosomal dominant retinitis pigmentosa (adRP) is frequently caused by mutations in RHO , the gene for rhodopsin. In previous experiments in dogs with the T4R mutation in RHO , an AAV2/5 vector expressing both an shRNA directed to human and dog RHO mRNA and an shRNA-resistant human RHO cDNA (AAV- RHO820-shRNA820 ) prevented retinal degeneration for more than 8 months following injection. To confirm that this same vector could protect the retinas of a different species and bearing a different RHO mutation, we injected mice transgenic for human P23H RHO at postnatal day 30 in one eye. For nine months, we monitored their retinal structure using spectral- domain optical coherence tomography (SD-OCT) and retinal function using electroretinography (ERG). We compared these to P23H RHO transgenic mice injected with AAV-GFP. Though retinas continued to thin over time, compared to control injected eyes, AAV-RHO820-shRNA820 slowed the loss of photoreceptor cells and decreased ERG amplitudes in AAV- RHO820-shRNA820 eyes during the nine-month study period. Unexpectedly, we also observed preservation of retinal structure and function in the untreated contralateral eyes of AAV- RHO820-shRNA820 treated mice. PCR analysis and western blots provided evidence that a low amount of vector from injected eyes was present in uninjected eyes.