Figure 1.

High-titer AAVs activate a strong anti-viral response in the adult mouse brain

(A) Low-magnification confocal images of GFP (green) at 30 dpi of low-titer (middle) and high-titer AAVs (right) intracranial injection. Scale bar, 200 μm. The left panel is the high-magnification confocal image of GFP co-stained with astrocytic marker S100β (red). Arrowheads indicate GFP-expressing astrocytes. Scale bar, 20 μm. (B) Quantified data of GFP covered area of AAV-infected mouse cortex. (C) Immunostaining of GFAP, Iba1, and CD68 in the AAV injected areas (30 dpi). Scale bar, 20 μm. (D) Quantification of GFAP, Iba1, and CD68 covered area within the injected sites. (E) Experimental schedule. PBS or low- or high-titer AAV9 were injected in the adult mouse cortex and the samples were collected at 10 dpi for further analysis. (F) Bar graph showing DEGs in PBS, 10⁸ GC, and 10¹⁰ GC groups. There are more than 1,000 DEGs between the high-titer group and the PBS or 10⁸ GC group. (G) Heatmap showing the top 30 DEGs in the 9 individuals. (H) The DEGs between high- and low-titer AAVs are plotted in the volcano map. Example genes are labeled in black corresponding to blue dots. Note, many DEGs are involved in antiviral, chemokine, BBB, and inflammatory cytokine biological activities. (I and J) qRT-PCR further demonstrated that two of the selected DEGs, TNF-α (I) and Cxcl10 (J), were dramatically upregulated in high-titer AAV treated mice (n = 3 mice per group, p < 0.01). (K) The KEGG-enriched bar graph showing the pathways by which high-titer virus elicited an immune response. Statistics were performed using one-way ANOVA analysis with Tukey test (post-hoc).