Induction of MFG-E8 by soluble factors released from degenerated neurons. (A) The levels of MFG-E8 secreted from microglia (Mi) and cortical neurons (Neu) treated with 20 μM glutamate (Glu) or 5 μM oligomeric amyloid β (oAβ) were measured by ELISA. In addition, MFG-E8 released from microglia exposed to neuronal conditioned medium (Neu CM) that had been treated with Glu or oAβ was also measured. Results are presented as the means with S.E.M. (n = 3). Glu- or oAβ-treated neuronal conditioned medium significantly induced MFG-E8 expression from microglia compared with the untreated control samples. ***: P <0.001 (one-way ANOVA with Dunnett’s post-hoc test). (B) The Western blot data of oAβ used in the present study. The blot was incubated in mouse anti-Aβ monoclonal antibody (6E10) (1:1,000, Chemicon). (C) The levels of the soluble secreted form of fractalkine (sFKN) released from cortical neurons treated with 20 μM glutamate (Glu) or 5 μM oligomeric amyloid β (oAβ) were measured. The results are presented as the means with S.E.M. (n = 3). Glu and oAβ treatment significantly induced sFKN release from neurons compared to the untreated control samples. **: P <0.01 (one-way ANOVA with Dunnett’s post-hoc test).