Effect of plant sterols and cholesterol on Aβ secretion. A, Human neuroblastoma SH-SY5Y cells stably transfected with APP695 were incubated with stigmasterol, β-sitosterol, campesterol, brassicasterol, or cholesterol (final concentration, 10 μm) and solvent control. Immunoprecipitation of secreted Aβ and WB analysis was performed with antibody W02. Representative WBs are shown. Error bars represent SD of the mean. B, Determination of Aβ40 and Aβ42 peptides in stigmasterol-treated APP695 transfected SH-SY5Y cells using ELISA technique. C, Determination of SEAP activity in presence of sterols (10 μm) in SH-SY5Y cells transiently transfected with SEAP. D, Lactate dehydrogenase assay in cells incubated with cholesterol, stigmasterol, β-sitosterol, campesterol, and brassicasterol in a final concentration of 10 μm compared with solvent control. No signs for increased cytotoxicity were observed in cells treated with sterols. Asterisks show the statistical significance compared with control (*p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001). Quantified data represent an average of at least three independent experiments (n ≥ 3). E, Representative WB analysis of actin protein level in SH-SY5Y cells incubated with plant sterols and cholesterol (final concentration of 10 μm).