PMC

B₁R blockade is not associated with changes in APP processing or in levels of LRP1, APOE, and neprilysin in Tg-SwDI mice. Representative blots (A) and quantitative results (B) of Western blot analysis showing that R715 administration (1 mg/kg, s.c., 8 weeks) causes no changes in the levels of APP, APP C-terminal fragments C99 and C83, or APP-cleaving enzymes BACE1, ADAM10, and ADAM17, compared with vehicle-treated animals. C and D: Effect of R715 treatment on the expression of LRP1, APOE, and neprilysin. GAPDH levels were used as loading controls. The values represent means ± SEM (N = 6 to 8).

B₁R blockade reduces neuroinflammation in Tg-SwDI mice. Representative blots (A) and quantitative results (B) of Western blot analysis demonstrating that s.c. administration of 1 mg/kg R715 for 8 weeks reduces the levels of phosphorylated-p65 NF-κB, but not of liver X receptor, peroxisome proliferator-activated receptor γ, or matrix metalloproteinase (MMP)-9, compared with vehicle-treated mice. GAPDH levels were used as loading controls. C: Cytokine expression determined by a cytokine array. Data were quantified as pixel density and presented as percentage of vehicle-treated controls. The values represent means ± SEM (N = 4 to 8). *P < 0.05, **P < 0.01.

B₁R blockade reduces glial cell activation in Tg-SwDI mice. A and B: Tg-SwDI mouse brains s.c. treated with 1 mg/kg R715 for 8 weeks exhibited a significant decrease in GFAP-positive astrocytes and CD68-, CD11b-, and CD45-positive microglia immunoreactivity versus vehicle-treated animals. Confocal analysis showing the colocalization of 6E10-positive Aβ deposits (red) and GFAP-positive astrocytes (green) (C) or Iba-1–positive microglia (green) (D). Representative photomicrographs were taken from the subiculum. Scale bars: 50 μm (GFAP and CD11b); 10 μm (CD45 and CD68); and 25 μm (C and D). The values represent means ± SEM (N = 5 to 6). **P < 0.01. The graph represents the average of inflammatory cells on the cortex, dentate gyrus, subiculum, and thalamus.

B₁R up-regulation affects Aβ deposition in Tg-SwDI brain. Mice s.c. treated with 1 mg/kg R715 for 8 weeks have no changes in the levels of Aβ₄₀ in the detergent-soluble fraction (A), whereas increased levels of Aβ₄₀ were observed in the detergent-insoluble fraction (B), and both detergent-soluble (C) and detergent-insoluble (D) Aβ₄₂ levels remained unchanged, as measured by ELISA. E and F: Aβ₄₀ immunoreactivity was increased in cortex (Ctx), thalamus (Tha), hippocampus (Hip), dentate gyrus (DG), and subiculum (Sub) of R715-treated mice when compared with the vehicle-treated group. E and G: R715 administration had no effect on Aβ₄₂ immunoreactivity in Tg-SwDI brains. Representative photomicrographs (H) and quantitative results (I) demonstrating increased thioflavin S–positive fibrillar Aβ deposits in R715-treated mice. Representative photomicrographs were taken from subiculum (E) and thalamus (H). Scale bars: 10 μm (E); 15 μm (H). The values represent means ± SEM (N = 5 to 6). *P < 0.05, **P < 0.01.

B₁R is up-regulated in Tg-SwDI brain. Representative blots (A) and quantitative results (B) of Western blot analysis showing the increased expression of B₁R in the brains of 10-month-old Tg-SwDI mice compared with age-matched nTg animals. GAPDH levels were used as loading controls. C: In nTg mice, confocal analysis demonstrated the colocalization of B₁R (red) and NeuN-positive (green) neurons, and elevated immunoreactivities of B₁R (red) colocalized with NeuN-positive neurons, collagen IV–positive vessels, and GFAP-positive astrocytes (all green) were observed in Tg-SwDI mice. Representative photomicrographs were taken from hippocampus (Hip; NeuN/B₁R), dentate gyrus (GFAP/B₁R), and thalamus (collagen IV/B₁R). D: B₁R immunoreactivity was increased in cortex (Ctx), thalamus (Tha), dentate gyrus (DG), and subiculum (Sub) of Tg-SwDI versus nTg mice. E: Confocal laser microscopy of B₁R (red), tomato lectin (green), and 6E10 (blue) demonstrated the colocalization of the B₁R and the vasculature in areas of Aβ deposits (6E10) in the brains of Tg-SwDI mice. Representative photomicrographs were taken from the thalamus. Scale bar = 10 μm. The values represent means ± SEM (N = 5 to 6). *P < 0.05, **P < 0.01.