Human RPE cell line ARPE-19 cells were cultured in Dulbecco's modified Eagle's medium:F12 (DMEM:F12, ATCC, Manassas, VA, USA) supplemented with 10% fetal bovine serum (Atlanta Biologicals, Norcross, GA, USA), 0.45% glucose, and penicillin/streptomycin 100 units/mL; 100 μg/mL (Life Technologies, Benicia, CA, USA), in a humidified incubator with 5% CO2 at 37°C. Cells were grown to 70% confluence and infected with lentiviral vectors at a multiplicity of infection (MOI) of 2 to 3. The media was changed 1 day after viral transduction and incubated for 3 days before selection with 1.5 μg/mL puromycin (EMD Millipore, Hayward, CA, USA) for 4 days. Genomic DNA, total mRNA, and conditioned media were collected at 14 days after viral transduction.