Figure 6.

Aβ-Th1 T Cells Upregulate MHCII Expression in Brain Endogenous Microglia of 5XFAD Mice

5XFAD and littermate (litt.) control mice were ICV-injected with either Aβ-Th1 T cells or PBS, killed at 14 or 21 dpi, and their brains excised and analyzed by using RNAscope (14 dpi) or flow cytometry (21 dpi).

(A) Flow cytometry plots demonstrating the gating strategy from single cells (left) to myeloid cells (CD45+ CD11b+; right).

(B) Flow cytometry plots demonstrating MHCII+ cells (out of CD11b+ CD45+ cells) in PBS→litt mice (left), PBS→5XFAD mice (middle), and Th1→5XFAD mice (right). The frequency of MHCII+ cells was quantified for all groups (right graph). Each symbol represents an individual mouse (n = 5 mice per group), and the bars represent means ± SEM of one experiment out of four performed.

(C) Flow cytometry plots demonstrating Ly6C+ cells (out of MHCII+ CD11b+ CD45+ cells) in the above-mentioned groups. The frequency of Ly6C+ cells was quantified for all groups (right graph). Each symbol represents an individual mouse (n = 5 per group), and the bars represent means ± SEM.

(D) Representative RNAscope fluorescence in situ hybridization images showing the co-expression of CD74 (red), P2ry12 (green) mRNA, and a DAPI nucleus counterstain (blue) in brain sections derived from Aβ-Th1→5XFAD mice (n = 5). Representative images of positive Ppib (green) and negative controls. Each puncta indicates a single mRNA molecule. The rectangular box demonstrates higher magnification of the framed area.

(E) A representative image showing P2ry12- (green) and CD74- (red) expressing cells. A higher magnification merge image of the framed area (top right panel) and the single-channel images (lower panels) show P2ry12+ (white arrows), P2ry12− (pink arrows), and CD74+ (yellow arrows) cells. Scale bars, 50 and 10 μm. *p < 0.05, ***p < 0.001 (one-way ANOVA).