Abstract
The aim of this study was to investigate potential biomarkers of Alzheimer's disease (AD). Changes in protein expression in brain tissues from AβPP/PS1 transgenic mice were evaluated using two-dimensional gel electrophoresis combined with LC-MS/MS. A total of 23 differentially expressed proteins were successfully identified in brain tissues of which 11 were validated by western blot. Then, the levels of these differentially expressed proteins in serum from AD patients and healthy controls were examined. Of these 11 proteins, levels of 5 changed in the same direction in the serum of AD patients as they did in mouse brain: cathepsin B, VDAC1, and cofilin-2 increased, and Alix and ACAP1 decreased. Alix, cofilin-2, and ACAP1 have not been previously associated with AD. More importantly, the serum levels of Alix, cofilin-2, and ACAP1 were significantly different between AD patients and healthy controls. Furthermore, the expressions of cathepsin B, cofilin-2, VDAC1, and ACAP1 strongly correlated with the Mini-Mental State Examination scores of the AD patients. The results indicate that these proteins are putative biomarkers of AD which may be useful in its diagnosis and in the evaluation of new anti-AD drugs both in pre-clinical and clinical studies.