Figure 6. apoE isoform–specific inhibition (apoE4>apoE3 and apoE2) of Aβ internalization at the abluminal surface of mouse brain capillaries in vitro is mediated by VLDLR.

(A) Specific binding of ¹²⁵I-labeled Aβ40 and Aβ42 complexes with apoE2 and apoE4 at 4°C in the absence and presence of receptor-specific blocking antibodies to VLDLR, LDLR, or LRP1 and excess unlabeled ligand at 0.5 μM. (B) Internalization of ¹²⁵I-Aβ40 in the absence and presence of receptor-specific blocking antibodies against LRP1 and of ¹²⁵I-labeled Aβ40–lipo-apoE2, Aβ40–lipo-apoE3, and Aβ40–lipo-apoE4 complexes for a period of 30 minutes. (C) Internalization of ¹²⁵I-labeled Aβ40, Aβ40–lipo-apoE2, Aβ40–lipo-apoE3, and Aβ40–lipo-apoE4 in the absence and presence of receptor-specific blocking antibodies against LRP1 and VLDLR. Means ± SEM; n = 3–5 experiments per group.