Fig. 3

The effect of transient induction of APOE ε4 during the amyloid-seeding stage. a Schematic of the doxycycline-inducible system to partially express APOE ε4 in AD-patient-derived iNs. Doxycycline was added at the time-point of amyloid-seeding stage (day 7) and was removed on day 14. b Immunostaining of EEA1 and Aβ (6E10) in AD patient fibroblasts harboring PSEN1 (left) or PSEN2 (right) mutation. Scale bar, 10 µm. c, d Immunostaining of EEA1- and  Aβ (6E10) in APOE ε4-expressing AD patient iNs harboring PSEN1 (c) or PSEN2 (d) mutation. Doxycycline was withdrawn from the culture 7 days after the initial APOE ε4 induction. Scale bar, 10 µm. e Quantification of EEA1- and  Aβ-positive puncta in AD patient iNs harboring PSEN1 mutation. Data represent mean ± SEM. ANOVA-test, **P < 0.01; n = 5 per sample. f Quantification of EEA1 and  Aβ-positive puncta in AD patient iNs harboring PSEN2 mutation. Data represent mean ± SEM. ANOVA-test, **P < 0.01; n = 5 per sample. g, h, i Western blot analysis of Aβ (6E10) oligomers in APOE ε4-expressing AD patient iNs on day 25. Data represent mean ± SEM. ANOVA-test, *P < 0.05; n = 4 per sample. + APOE4 (day 7): AD patient iNs expressing APOE ε4 from day 7; + APOE4 (day 7–14): AD patient iNs expressing APOE ε4 during days 7–14; + APOE4 (day 14): AD patient iNs expressing APOE ε4 from day 14; -APOE4: AD patient iNs with no APOE ε4 expression