FIGURE 5.

Acceleration of Aβ uptake into microglia by exosome. A and B, N2a-derived exosomes were incubated with 25 μm Aβ42 at 37 °C for 5 h. The preincubated mixtures were then added to BV-2 cells or primary microglia (final concentration of Aβ, 0.5 μm) and further incubated for the indicated times. Levels of Aβ42 in BV-2 cells (A) and in conditioned media (B) were quantified by ELISA. Values are means ± S.E. *, p < 0.05; **, p < 0.01; ***, p < 0.001; t test. C, 50 μm Aβ42 was incubated at 37 °C for 5 days to form amyloid fibrils. The fibrils were incubated with or without N2a-derived exosomes at 37 °C for 5 h. The incubation mixtures were added to BV-2 cells (final concentration of Aβ, 0.5 μm) and incubated for the additional times. The levels of intracellular Aβ in BV-2 cells were measured by ELISA. Values are means ± S.E. D, N2a-derived exosomes (Exo) were incubated with 25 μm Aβ42 at 37 °C for 5 h, then with AV or CTB for an additional 15 min at 37 °C. The mixtures were applied to BV-2 cells or primary microglia and incubated for 3 h. The intracellular levels of Aβ were measured using ELISA. Values represent as the mean ± S.E. **, p < 0.01; t test.