Promoter specificity and volume of GFP-expression after AAV injection at different postnatal stages.

A, For each promoter and time point used, the proportion of neurons, oligodendrocytes, and astrocytes was calculated as a percentage of the total number of cells expressing GFP (n = 3). B, Summary of the percentage of GFP-expressing cells relative to the three different neural populations in the target area. Contrary to neonatal AAV-delivery, the MBP promoter robustly targeted the oligodendrocyte population following injection at P10 and P90 (MBP-P0: 3.0±0.2%, MBP-P10: 68.3±9.2%, MBP-P90: 53.3±12.5%). The GFAP promoter resulted in robust transgene expression in the astrocyte population regardless of the time point of AAV-injection (GFAP-P0: 52.0±5.6%, GFAP-P90: 65.4±3.1%). C, Volume showing GFP expression after AAV-MBP-GFP or AAV-GFAP-GFP delivery. Vector delivery at early time points result in higher efficacy compared to the adult stage (MBP-P0: 23.5±1.7 mm³, MBP-P10: 23.1±1.8 mm³, MBP-P90: 8.3±1.2 mm³, GFAP-P0: 26.7±5.8 mm³, GFAP-P90: 5.8±1.2 mm³). D, Vector spread relative to the whole brain volume (MBP-P0: 5.9±0.4%, MBP-P10: 4.6±0.4%, MBP-P90: 1.7±0.2%, GFAP-P0: 6.7±50.7%, GFAP-P90: 1.2±0.2%). p<0.001, 2-way ANOVA and Bonferroni post-test.