Fig. 3

Mt3 deletion decreases Aβ endocytosis. a, b Confocal fluorescence micrographs of WT and Mt3 ^−/− astrocytes. Cells were incubated with 200 nM FITC-Aβ_1–42 (A) or FITC-Aβ_1–40 (B) (green dots, arrowheads) for 15 min at 37 °C. The plasma membrane was stained with Alexa Fluor 594-WGA (red). Both the FITC-Aβ_1–42 and FITC-Aβ₁₋40 uptake were noticeably reduced in Mt3 ^−/− cells compared with WT control cells. Again, addition of 10 μg/ml of the Mt3 peptide partly restored the endocytosis of FITC-Aβ_1–42 and FITC-Aβ_1–40. Scale bar, 20 μm. c, d Bars depict the percentage of FITC(+) cells in the above experiments. The values were normalized to the percentage of FITC-Aβ_1–42 ⁺ (C) or FITC-Aβ_1–40 ⁺ (D) cells in the WT controls, defined as 100 % (**P < 0.01 vs. WT CTL; n = 4 cultures). e Western blots for Aβ monomer and oligomers. Astrocytes from WT and Mt3 ^−/− mice were incubated with 1 μM Aβ monomers. After 24 h, the cells were lysed and immunoblotted with an anti-6E10 antibody. f, g Bars indicate changes in the density ratio of Aβ oligomers (F) and Aβ monomers (G) relative to tubulin. All ratio values were normalized to the ratio in WT controls, which was defined as 1 (**P < 0.01 vs. WT CTL; *P < 0.05 vs. Mt3 ^−/− CTL or WT Aβ groups; n = 4 experiments)