Figure 5.

TUDCA modulates cleavage of tau by caspase-3 in primary cortical neurons incubated with fibrillar Aβ _1–42. Cells were incubated with 20μM fibrillar Aβ_1–42, or no addition (control), ± 100 μM TUDCA for 24 h. In coincubation experiments, TUDCA was added 12 h prior to incubation with Aβ_1–42. Colocalization of active caspase-3 and cleaved tau was evaluated by confocal immunofluorescence microscopy. Apoptotic nuclei were visualized with Hoechst staining. Total proteins were extracted and subjected to Western blot analysis. A: Confocal microscopy and colocalization of apoptotic nuclei, active caspase-3, and cleaved tau in cells exposed to β_1–42. B: Confocal microscopy and colocalization of apoptotic nuclei and cleaved tau in cells exposed to Aβ (a) and Aβ + TUDCA (b) (top); representative immunoblot of caspase-cleaved tau in cells after treatment with Aβ ± TUDCA (bottom). The blot was normalized to total tau protein levels. Scale bar: 20 μm.