A microliter-scale high-throughput screening system with quantum-dot nanoprobes for amyloid-β aggregation inhibitors

PLoS One. 2013 Aug 26;8(8):e72992. doi: 10.1371/journal.pone.0072992. eCollection 2013.

Abstract

The aggregation of amyloid β protein (Aβ) is a key step in the pathogenesis of Alzheimer's disease (AD), and therefore inhibitory substances for Aβ aggregation may have preventive and/or therapeutic potential for AD. Here we report a novel microliter-scale high-throughput screening system for Aβ aggregation inhibitors based on fluorescence microscopy-imaging technology with quantum-dot Nanoprobes. This screening system could be analyzed with a 5-µl sample volume when a 1536-well plate was used, and the inhibitory activity could be estimated as half-maximal effective concentrations (EC50). We attempted to comprehensively screen Aβ aggregation inhibitors from 52 spices using this system to assess whether this novel screening system is actually useful for screening inhibitors. Screening results indicate that approximately 90% of the ethanolic extracts from the spices showed inhibitory activity for Aβ aggregation. Interestingly, spices belonging to the Lamiaceae, the mint family, showed significantly higher activity than the average of tested spices. Furthermore, we tried to isolate the main inhibitory compound from Saturejahortensis, summer savory, a member of the Lamiaceae, using this system, and revealed that the main active compound was rosmarinic acid. These results demonstrate that this novel microliter-scale high-throughput screening system could be applied to the actual screening of Aβ aggregation inhibitors. Since this system can analyze at a microscopic scale, it is likely that further minimization of the system would easily be possible such as protein microarray technology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / analysis*
  • High-Throughput Screening Assays*
  • Molecular Probes*
  • Nanostructures*
  • Quantum Dots*

Substances

  • Amyloid beta-Peptides
  • Molecular Probes

Grants and funding

This work is supported by the Yamazaki Spice Promotion Foundation (K.T.), MuIT Grant for Selective Research (K.T.), and JSPS KAKENHI Grant Numbers 25350974 (K.T.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.