method (Polysciences, Inc.; Warrington, PA). For each 15-cm plate, a total of 100 μg of DNA (33.3 μg of each plasmid) was added to a 150 mM NaCl solution, in a final volume of 2 mL; 12.5 μL of PEI (16 mg/ml) was then added while mixing constantly to favor the formation of DNA/PEI complexes. After 10 min of incubation, the complexes were added drop wise to AAV293 cells maintained in DMEM supplemented with 10% FBS, 4 mM L-glutamine, 1 mM sodium pyruvate at 37 °C and 5% CO2. After 72 h, cells were collected for viral particle extraction and purification. Viral titering was performed by qPCR with specific primers for the WPRE region of the AAV vectors: 5′-CCGTTGTCAGGCAACGTG-3′ (forward) and 5′-AGCTGACAGGTGGTGGCAAT-3′ (reverse). Control viruses (AAV8-CaMKII-EGFP, AAV8-hSyn-EGFP, and AAV8-hSyn-DIO-mCherry) were obtained from the UNC Viral Vector Core (Chapel Hill, NC).
