Fig. 3.

β-Amyloid-induced TNFα and IL1-β gene expression require Syk activity. THP-1 cells were transiently transfected with a TNFα reporter construct and assayed for promoter activity 48 hr later. The cells were cotransfected with a β-galactosidase reporter construct to control for transfection efficiency. A, During the last 8 hr, cells were incubated in serum-free RPMI alone (black bars) or stimulated for increasing times (0–8 hr) with fibrillar Aβ25–35 (60 μm) (gray bars). B, To determine whether proximal tyrosine kinase and NFκB activities were required for TNFα promoter activity, the cells were incubated with drug/vehicle only (black bars) or with fibrillar Aβ25–35 (60 μm) (light gray bars) or Aβ1–40 (60 μm) (dark gray bars) for the last 5 hr in the presence or absence of PP1 (5 μm), piceatannol (10 μm), or 100 μg/ml SN-50 peptide. The data shown represent the average (±SEM) of three independent experiments. Unpaired ANOVA was performed with Tukey-Kramer post-comparison to evaluate statistical significance (**p < 0.001). C, To determine whether proximal tyrosine activities were required for β-amyloid-dependent IL1-β expression, the cells were incubated with drug/vehicle only or fibrillar Aβ25–35 (60 μm) for 5 hr in the presence or absence of PP1 (5 μm) or piceatannol (10 μm). Cell lyates were resolved by 9% SDS-PAGE and Western-blotted using anti-IL-1β antibody.