PSAPP小鼠中的淀粉样斑块比人类阿尔茨海默病中的斑块结合的金属更少。
Amyloid plaques in PSAPP mice bind less metal than plaques in human Alzheimer's disease.
作者信息
Leskovjan Andreana C, Lanzirotti Antonio, Miller Lisa M
机构信息
Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11790, USA.
出版信息
Neuroimage. 2009 Oct 1;47(4):1215-20. doi: 10.1016/j.neuroimage.2009.05.063. Epub 2009 May 28.
Amyloid beta (Abeta) is the primary component of Alzheimer's disease (AD) plaques, a key pathological feature of the disease. Metal ions of zinc (Zn), copper (Cu), iron (Fe), and calcium (Ca) are elevated in human amyloid plaques and are thought to be involved in neurodegeneration. Transgenic mouse models of AD also exhibit amyloid plaques, but fail to exhibit the high degree of neurodegeneration observed in humans. In this study, we imaged the Zn, Cu, Fe, and Ca ion distribution in the PSAPP transgenic mouse model representing end-stage AD (N=6) using synchrotron X-ray fluorescence (XRF) microprobe. In order to account for differences in density in the plaques, the relative protein content was imaged with synchrotron Fourier transform infrared microspectroscopy (FTIRM) on the same samples. FTIRM results revealed a 61% increase in protein content in the plaques compared to the surrounding tissue. After normalizing to protein density, we found that the PSAPP plaques contained only a 29% increase in Zn and there was actually less Cu, Fe, and Ca in the plaque compared to the surrounding tissue. Since metal binding to Abeta is thought to induce redox chemistry that is toxic to neurons, the reduced metal binding in PSAPP mice is consistent with the lack of neurodegeneration in these animals. These findings were in stark contrast to the high metal ion content observed in human AD plaques, further implicating the role of metal ions in human AD pathology.
β淀粉样蛋白(Aβ)是阿尔茨海默病(AD)斑块的主要成分,是该疾病的一个关键病理特征。人类淀粉样斑块中锌(Zn)、铜(Cu)、铁(Fe)和钙(Ca)等金属离子含量升高,被认为与神经退行性变有关。AD转基因小鼠模型也表现出淀粉样斑块,但未能表现出在人类中观察到的高度神经退行性变。在本研究中,我们使用同步加速器X射线荧光(XRF)微探针,对代表晚期AD的PSAPP转基因小鼠模型(N = 6)中的Zn、Cu、Fe和Ca离子分布进行成像。为了考虑斑块中密度的差异,在相同样本上使用同步加速器傅里叶变换红外显微光谱(FTIRM)对相对蛋白质含量进行成像。FTIRM结果显示,与周围组织相比,斑块中的蛋白质含量增加了61%。在对蛋白质密度进行归一化后,我们发现PSAPP斑块中的Zn仅增加了29%,实际上与周围组织相比,斑块中的Cu、Fe和Ca含量更低。由于金属与Aβ的结合被认为会诱导对神经元有毒性的氧化还原化学反应,PSAPP小鼠中金属结合的减少与这些动物缺乏神经退行性变是一致的。这些发现与在人类AD斑块中观察到的高金属离子含量形成鲜明对比,进一步暗示了金属离子在人类AD病理学中的作用。