Table 1. Design of different AAV constructs.

The single-stranded (ss) pAAV2 that contained chicken β-actin promoter (CBAp), cytomegalovirus enhancer (CMVe), CBA intron (CBAi), woodchuck hepatitis virus post-transcriptional regulatory element (WPRE), and enhanced green fluorescent protein (EGFP) transgene was packaged in different AAV capsids-1–9 and rh10 (a). The self-complementary (sc) double-stranded vector expressing humanized GFP (GFP) and containing SV40-derived intron (SV40i) was constructed by mutating one inverted terminal repeat (mut ITR), such that the viral Rep protein cannot generate the ss DNA nick (b). Microglia-specific promoters (F4/80p or CD68p) containing a minute virus of mice intron (MVMi) was used to replace the hybrid CBA (hCBA) promoter and the SV40i (c, d). The length of different plasmid elements is depicted in nucleotides (nt) atop the corresponding elements. All constructs contain polyA element derived from bovine growth hormone (bGHpA). These constructs containing GFP or IL-6 transgenes were packaged in wild-type (WT) AAV6 and/or capsid-modified AAV6 (b–d). TM6 refers to the triple-mutant AAV6 capsid (Y731F/Y705F/T492V) (c, d). AAV, adeno-associated viruses; IL-6, interleukin-6.