Fig. 2: Highly efficient and specific microglial targeting by AAV9.Iba1.miR-9.T.miR-129-2-3p.T.

a Schema of the AAV construct comprising Iba1 promoter, GFP, and two different quadruplex sequences complementary to miR-9 and miR-129-2-3p. Mice received different doses of AAV (3.9 × 10¹² vg/mL) to the cerebral cortex (0.5 μL), striatum (1 μL) and cerebellum (10 μL). One week after the viral injection, the mouse brains were examined by immunohistochemistry. (b-d)Immunohistochemistry of the cerebral cortex. Square regions in b were enlarged. Note the strong and efficient GFP expression in microglia with weak and rare transduction of Iba1-negative non-microglial cells (arrows). e–j Highly specific transduction of microglia in the striatum (e–g) and cerebellum (h–j). Square regions in (e, h) were enlarged. Scale bars; 100 μm (b, e, h) and 20 μm (c, d, f, g, i, j). GL granule cell layer, ML molecular layer.