AAV-Mediated EPO Gene Reduction Inhibits Choroidal Neovascularization

Abstract

Objective: To probe the role of Erythropoietin (EPO) in the progress of choroidal neovascularization (CNV). AAV-mediated EPO shRNA was used to target retinal pigment epithelium (RPE) in order to find a potential therapeutic approach to neovascular age-related macular degeneration (nAMD). Methods: This study was based on a controlled comparison experimental design. The in vitro efficiency of the EPO shRNA plasmid was tested in HEK293T cell culture. Two-month-old C57/B6J mice were used in this study. The right eyes were the experimental group and were injected with AAV1-sCBA-GFP-EPO-shRNA subretinally. The left eyes were the control group and were injected with AAV1-sCBA-GFP subretinally. Laser burns were performed to induce choroidal neovascularization in each eye 3 weeks after injection. Fundus images were taken immediately after that to make sure RPE was infected by the virus and the animal model was constructed successfully. The mice were sacrificed 15 days after laser photocoagulation, RPE flat-mounts were used to quantify the area of the CNV lesions. Statistical comparisons between groups were analyzed with a student's t test. Results: EPO shRNA had a statistically significantly efficiency (t=6.080, P=0.022) in HEK293T cell culture. The gene reduction rate of EPO shRNA was 69.6%. Successful virus transfection and model construction could be seen on fundus images. The average area of CNV lesions in the experimental eyes was 44.7% less than that in the control eyes. This reduction was also statistically significant (t=4.279, P=0.001). Conclusions: AAV-mediated EPO shRNA significantly reduces the progress of CNV lesions. This suggests that knocking down the EPO gene with AAV-mediated EPO shRNA can be a potential treatment for nAMD in the future. Key words: adeno-associated virus; choroidal neovascularization; erythropoietin; neovascular age-related macular degeneration