Báo cáo khoa học: b-Amyloid protein oligomers induced by metal ions and acid pH are distinct from those generated by slow spontaneous ageing at neutral pH

B-Amyloid Protein Oligomers Induced by Metal Ions and Acid pH Are Distinct from Those Generated by Slow Spontaneous Ageing at Neutral pH

Authors: Genevieve M. J. A. Klug, Dusan Losic, Supundi S. Subasinghe, Marie-Isabel Aguilar, Lisandra L. Martin, and David H. Small

Field: Biochemistry and Molecular Biology

Document Content:
This research investigates the aggregation and conformation of β-amyloid protein (Aβ1-40) under various conditions, including the influence of metal ions and pH. The study employed multiple analytical techniques such as SDS/PAGE, native PAGE, atomic force microscopy, Congo red binding, sedimentation, and turbidity assays. Findings indicate that Aβ aggregation can occur via at least two distinct mechanisms, leading to the formation of different types of aggregates with varying cytotoxic properties. Aggregation induced by low pH or metal ions (Fe2+, Cu2+, Zn2+) results in rapid, unstable aggregates, while spontaneous ageing at neutral pH leads to slow formation of stable, high molecular mass species. The study highlights that different methods of analysis can yield discrepant results regarding Aβ aggregation, suggesting that the observed aggregates may differ in their stability and properties. Furthermore, Aβ aged under neutral pH conditions demonstrated greater cytotoxicity compared to that aged at acidic pH.

Detailed Table of Contents:

• Introduction
• Materials and methods
• Materials
• Synthesis and solubilization of Aβ1-40
• Electrophoresis and Western blotting
• SDS and non-SDS/PAGE in two dimensions
• Congo red binding assay
• Sedimentation assay of Aβ aggregation
• Atomic force microscopy
• Turbidity assay of Aβ aggregation
• Cell viability (MTS) assay
• Results
• Analysis of Aβ by PAGE
• Effect of pH and metal ions – PAGE analysis
• Effect of pH and metal ions – CR binding and sedimentation analysis
• Analysis of Aβ oligomerization by AFM
• Reversibility of Aβ aggregation – turbidity assay
• Cytotoxicity of oligomeric Aβ
• Discussion
• Acknowledgements
• References