Label-Free High-Throughput Screening Assay for Inhibitors of Alzheimer’s Amyloid-β Peptide Aggregation Based on MALDI MS

Aggregation of amyloid-β (Aβ) peptides is causatively linked to Alzheimer's disease (AD); thus, suppression of this process by small molecule inhibitors is a widely accepted therapeutic and preventive strategy for AD. Screening of the inhibitors of Aβ aggregation deserves much attention; however, despite intensive efforts, there are only a few high-throughput screening methods available, all of them having drawbacks related to the application of external fluorescent probes or artificial Aβ derivatives. We have developed a label-free MALDI MS-based screening test for inhibitors of Aβ₄₂ fibrillization that exhibits high sensitivity, speed, and automation possibilities suitable for high-throughput screening. The test was evaluated by transmission electron microscopy and compared with a fluorimetric thioflavin-based assay, where interference of a number of tested compounds with thioflavin T binding and/or fluorescence caused false-positive results. The MALDI MS-based method can significantly speed up in vitro screening of compound libraries for inhibitors of Aβ₄₂ fibrillization.