Fig. 4: Inhibition of blood-derived pathogenic Th17 cells protects microglia phagocytic function defects and reduces BBB disruption in the cortex of young APP/PS1 mice in parabiosis with Smpd1^ox/ox mice.

a mRNA levels of inflammatory markers in BV2 microglial cells (n = 4/group). b Left, immunofluorescence images (Iba-1, Scale bars, 50 μm) and imaris-based three-dimensional images (Scale bars, 10 μm) of BV2 microglial cells. Right, imaris-based automated quantification of microglial morphology (n = 6/group). c Top, immunofluorescence images of microglia with Fluor 555-labeled Aβ. Scale bars = 50 μm. Bottom, quantification of the Fluor 555-labeled Aβ uptake (n = 6/group). d mRNA levels of inflammatory markers in the cortex (n = 4/group). e Immunostaining images and quantification of Aβ (ThioS, green) positive cells and microglia (Iba1, red) (n = 5/group). Scale bars = 10 μm. f Imaris-based automated quantification of microglial morphology (n = 5/group). g Left, immunofluorescence images of ThioS (Aβ plaques, green) encapsulated within Lamp1⁺ structures (phagolysosomes, blue) in microglia (Iba1, red) present in the cortex. Scale bars, 20 μm; 3D reconstruction from confocal image stacks scale bars, 10 μm. Right, quantification of microglia volume occupied by Lamp1⁺ phagolysosomes, percent of microglia containing Aβ-loaded phagolysosomes and Aβ encapsulated in phagolysosomes (n = 5/group). h Western blot analysis and quantification of tight junction proteins (Zo1, Claudin5, Occludin) in the cortex (n = 4/group). i mRNA levels of tight junction (AD from WT-AD pair, AD from OX-AD pair/IL17 ab, n = 4; AD from OX-AD pair/con ab, n = 5). j Western blot analysis and quantification of fibrin and thrombin (n = 4/group). a–c, h–j One-way analysis of variance, Tukey’s post hoc test. d–g Two-tailed student’s t test. All error bars indicate s.e.m. All data analysis was done at 4.5-mo-old mice. Source data are provided as a Source Data file.