Vitreal delivery of AAV vectored Cnga3 restores cone function in CNGA3−/−/Nrl−/− mice, an all-cone model of CNGA3 achromatopsia
Human Molecular Genetics, Vol. 24, No.13, 3699–3707, doi: 10.1093/hmg/ddv114
The CNGA3−/−/Nrl−/− mouse is a cone-dominant model with Cnga3 channel deficiency, which partially mimics the all cone foveal structure of human achromatopsia 2 with CNGA3 mutations. Although subretinal (SR) AAV vector administration can transfect retinal cells efficiently, the injection-induced retinal detachment can cause retinal damage, particularly when SR vector bleb includes the fovea. We therefore explored whether cone function–structure could be rescued in CNGA3−/−/Nrl−/− mice by intravitreal (IVit) delivery of tyrosine to phenylalanine (Y-F) capsid mutant AAV8. We find that AAV-mediated CNGA3 expression can restore cone function and rescue structure following IVit delivery of AAV8 (Y447, 733F) vector. Rescue was assessed by restoration of the cone-mediated electroretinogram (ERG), optomotor responses, and cone opsin immunohistochemistry. Demonstration of gene therapy in a cone-dominant mouse model by IVit delivery provides a potential alternative vector delivery mode for safely transducing foveal cones in achromatopsia patients and in other human retinal diseases affecting foveal function.