FIGURE 5.
Exosomes isolated from medium of amyloid peptide-treated astrocytes induce apoptosis. Wild type astrocytes were loaded with Vybrant CM-DiI and then incubated with fresh medium supplemented with 20 μm Aβ25–35. A, red fluorescence is visible in a perinuclear compartment and vesicles along processes and at the cell membrane (arrows). Bar = 5 μm. B, exosomes were resuspended and added to wild type astrocytes. Only astrocytes taking up exosomes (red fluorescent, arrows) round up and show condensed nuclei (Hoechst dye, blue). Bar = 10 μm. C, confocal laser scanning immunofluorescence microcopy of exosome-treated astrocytes using TUNEL staining and anti-ceramide rabbit IgG (Cy5, pseudo-colored in blue). Bar = 20 μm. D, quantification of apoptosis induced by exosomes from Aβ25–35-treated wild type astrocytes. n = 3, p < 0.01. E, quantification of apoptosis induced by Aβ25–35 in the presence of anti-ceramide (Anti-Cer) or PAR-4 IgG (1 μg/ml). n = 5; p < 0.01. Con, control. *, comparison control IgG with amyloid-treated control IgG; **, comparison anti ceramide IgG with amyloid-treated anti ceramide IgG; ***, comparison anti PAR-4 IgG with amyloid-treated anti PAR-4 lgG.