Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, United Kingdom CB2 1EW.
J Am Chem Soc. 2013 Jan 30;135(4):1491-8. doi: 10.1021/ja3103567. Epub 2013 Jan 22.
Oligomers of the 40 and 42 residue amyloid-β peptides (Aβ40 and Aβ42) have been implicated in the neuronal damage and impaired cognitive function associated with Alzheimer's disease. However, little is known about the specific mechanisms by which these misfolded species induce such detrimental effects on cells. In this work, we use single-molecule imaging techniques to examine the initial interactions between Aβ monomers and oligomers and the membranes of live cells. This highly sensitive method enables the visualization of individual Aβ species on the cell surface and characterization of their oligomerization state, all at biologically relevant, nanomolar concentrations. The results indicate that oligomers preferentially interact with cell membranes, relative to monomers and that the oligomers become immobilized on the cell surface. Additionally, we observe that the interaction of Aβ species with the cell membrane is inhibited by the presence of ATP-independent molecular chaperones. This study demonstrates the power of this methodology for characterizing the interactions between protein aggregates and the membranes of live neuronal cells at physiologically relevant concentrations and opens the door to quantitative studies of the cellular responses to potentially pathogenic oligomers.
寡聚体的 40 和 42 残基淀粉样蛋白-β 肽（Aβ40 和 Aβ42）已牵连在神经元损伤和认知功能障碍与老年痴呆症。然而，人们对这些错误折叠的物种如何诱导细胞产生这种有害影响的具体机制知之甚少。在这项工作中，我们使用单分子成像技术来研究 Aβ单体和寡聚体与活细胞的膜之间的初始相互作用。这种高灵敏度的方法可以在生物相关的纳摩尔浓度下，可视化细胞表面上的单个 Aβ物种，并对其寡聚状态进行表征。结果表明，寡聚体优先与细胞膜相互作用，相对于单体和寡聚体固定在细胞膜上。此外，我们观察到 Aβ物种与细胞膜的相互作用被 ATP 非依赖性分子伴侣的存在所抑制。这项研究证明了该方法在生理相关浓度下对蛋白质聚集体与活神经元细胞膜之间相互作用进行表征的强大功能，并为定量研究细胞对潜在致病寡聚体的反应开辟了道路。
