J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
J Neurochem. 2011 May;117(3):538-53. doi: 10.1111/j.1471-4159.2011.07225.x. Epub 2011 Mar 23.
In Alzheimer's disease, the amyloid-β peptide (Aβ) interacts with distinct proteins at the cell surface to interfere with synaptic communication. Recent data have implicated the prion protein (PrP(C)) as a putative receptor for Aβ. We show here that Aβ oligomers signal in cells in a PrP(C)-dependent manner, as might be expected if Aβ oligomers use PrP(C) as a receptor. Immunofluorescence, flow cytometry and cell surface protein biotinylation experiments indicated that treatment with Aβ oligomers, but not monomers, increased the localization of PrP(C) at the cell surface in cell lines. These results were reproduced in hippocampal neuronal cultures by labeling cell surface PrP(C). In order to understand possible mechanisms involved with this effect of Aβ oligomers, we used live cell confocal and total internal reflection microscopy in cell lines. Aβ oligomers inhibited the constitutive endocytosis of PrP(C), but we also found that after Aβ oligomer-treatment PrP(C) formed more clusters at the cell surface, suggesting the possibility of multiple effects of Aβ oligomers. Our experiments show for the first time that Aβ oligomers signal in a PrP(C)-dependent way and that they can affect PrP(C) trafficking, increasing its localization at the cell surface.
在阿尔茨海默病中，淀粉样β肽（Aβ）与细胞表面的不同蛋白质相互作用，干扰突触通讯。最近的数据表明朊病毒蛋白（PrP(C)）可能是 Aβ 的受体。我们在这里表明，Aβ 低聚物以 PrP(C)依赖的方式在细胞中发出信号，如果 Aβ 低聚物将 PrP(C)用作受体，这可能是意料之中的。免疫荧光、流式细胞术和细胞表面蛋白生物素化实验表明，用 Aβ 低聚物处理而非单体处理会增加细胞系中 PrP(C)在细胞表面的定位。在海马神经元培养物中，通过标记细胞表面 PrP(C)重现了这些结果。为了了解 Aβ 低聚物这种作用可能涉及的机制，我们在细胞系中使用了活细胞共聚焦和全内反射显微镜。Aβ 低聚物抑制了 PrP(C)的组成性内吞作用，但我们还发现，在用 Aβ 低聚物处理后，PrP(C)在细胞表面形成更多的簇，这表明 Aβ 低聚物可能具有多种作用。我们的实验首次表明，Aβ 低聚物以 PrP(C)依赖的方式发出信号，并且它们可以影响 PrP(C)的运输，增加其在细胞表面的定位。
