Effect of LPS on secretase activities and amyloidogenic proteins expression. The activities of α-, β-secretase (A, B) and γ-secretase (C) were assessed by using commercially available assay kits. Data represent mean ± S.E. (n = 5). *Significant different from control group (p < 0.05). The expression of APP, BACE and C99 (D) were detected by Western blotting using specific antibodies. Each blot is representative for five experiments. β-actin protein was used here as an internal control.