FIGURE 1.

Effect of PA on extracellular and intracellular Aβ accumulation. 48-h treatment of SH-SY5Y-APP cells with 100 μm PA produced significant elevations in eAβ40 (A) and eAβ42 (B), as measured by ELISA in conditioned medium (p < 0.0001 and p = 0.0003, n = 5). eAβ40 and eAβ42 production were blocked by treatment with the γ-secretase inhibitor DAPT. PA also produced a significant accumulation of iAβ40 (C) and iAβ42 (D) in these cells (p = 0.0004 and p = 0.0225, n = 3). In cell extracts, ELISA measurements remained unchanged upon treatment with DAPT or DAPT+PA, indicating that signal measured in non-treated groups is attributable to background and that the increase in iAβ signal with PA treatment is a true increase in Aβ peptide levels. Similar to results obtained with SH-SY5Y-APP cells, treatment of H4-APP cells with PA produced significant accumulations of eAβ40 (E) (p = 0.0028, n = 3) and iAβ40 (F) (p = 0.0058, n = 3).