APOE4 disrupts the PC transcriptome. (A) Volcano plot showing DEGs in PCs of 2–3-mo-old (red) and 9–12-mo-old (cyan) E4F compared with E3F mice. (B and C) Bar charts reporting the number of DEGs in PCs encoding proteins with known function in each functional class of 2–3-mo-old (B) and 9–12-mo-old (C) E4F compared with E3F mice. (D) Plot comparing the average log₂ fold-change of DEGs in PCs of 2–3-mo-old (y axis) and 9–12-mo-old (x axis) E4F compared with E3F mice (n = 25 DEGs). All data in A–D are from four mice per group. (E and F) CD13⁺ PC coverage (magenta) of lectin⁺ endothelial profiles (blue) in the cortex (E; bar = 25 µm), and quantification of PC coverage in 2–3-, 4–6-, and 9–12-mo-old E3F and E4F mice (F). (G) Correlation between PC vascular coverage and extravascular fibrinogen deposits in cortex. n = 30 mice. In F, mean ± SEM; significance by one-way ANOVA with Bonferroni post hoc test; n = 5 mice per group. In G, significance by Pearson correlation. *, P < 0.05; ***, P < 0.001; ****, P < 0.0001. ECM, extracellular matrix.