taurochenodeoxycholic-acid and benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone

Early onset familial Alzheimer's disease (FAD) is linked to autosomal dominant mutations in the amyloid precursor protein (APP) and presenilin 1 and 2 (PS1 and PS2) genes. These are critical mediators of total amyloid beta-peptide (Abeta) production, inducing cell death through uncertain mechanisms. Tauroursodeoxycholic acid (TUDCA) modulates exogenous Abeta-induced apoptosis by interfering with E2F-1/p53/Bax. Here, we used mouse neuroblastoma cells that express either wild-type APP, APP with the Swedish mutation (APPswe), or double-mutated human APP and PS1 (APPswe/DeltaE9), all exhibiting increased Abeta production and aggregation. Cell viability was decreased in APPswe and APPswe/DeltaE9 but was partially reversed by z-VAD.fmk. Nuclear fragmentation and caspase 2, 6 and 8 activation were also readily detected. TUDCA reduced nuclear fragmentation as well as caspase 2 and 6, but not caspase 8 activities. p53 activity, and Bcl-2 and Bax changes, were also modulated by TUDCA. Overexpression of p53, but not mutant p53, in wild-type and mutant neuroblastoma cells was sufficient to induce apoptosis, which, in turn, was reduced by TUDCA. In addition, inhibition of the phosphatidylinositide 3'-OH kinase pathway reduced TUDCA protection against p53-induced apoptosis. In conclusion, FAD mutations are associated with the activation of classical apoptotic pathways. TUDCA reduces p53-induced apoptosis and modulates expression of Bcl-2 family.

Topics: Alzheimer Disease; Amino Acid Chloromethyl Ketones; Amyloid beta-Protein Precursor; Animals; Antiviral Agents; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Caspases; Cell Line, Tumor; Cysteine Proteinase Inhibitors; Enzyme Activation; Humans; In Situ Nick-End Labeling; Membrane Proteins; Mice; Mutation; Neuroblastoma; Presenilin-1; Presenilin-2; Proto-Oncogene Proteins c-bcl-2; Taurochenodeoxycholic Acid; Transfection; Tumor Suppressor Protein p53