荧光相关光谱技术（FCS）检测阿尔茨海默病患者脑脊液中单个淀粉样β蛋白聚集物
发布时间：
2023-05-06
分类：
阿尔兹海默症与实质内生长的板块淀粉样沉积物相关，淀粉样蛋白斑是由可溶性淀粉样β-蛋白单体逐步沉积并转化为非溶性及纤维性聚集体，这一过程被描述为具有慢成核和快速生长动力学单体的“种子聚合”。至今，阿尔兹海默症的发生发展以及治疗方法的开发仍为学界难题。1998年, Nature Medicine 发表了德国生物物理研究所的M.Pitschke 团队应用FCS技术研究β-amyloid聚合的工作。这一研究时至今日仍为后续研究的良好范本。在本研究中，作者应用FCS检测到单个淀粉样β肽在阿尔兹海默症病人的脑脊液中的聚集。可溶性淀粉样β-蛋白单体一般存在于细胞外间隙和脑脊液中，而非溶性聚合物目前只能通过活检及尸检检查脑组织。实验对Aβ1-40，Aβ1-42多肽主氨基使用Cy2(Amersham) 进行荧光标记，将标记荧光的多肽作为探针加入患者脑脊液样本中观察淀粉样β肽中的聚集现象。实验结果表明，15位阿尔兹海默症患者的脑脊液样品中呈现“种子聚合”状态，而19位年龄相仿的对照组中并未呈现“种子聚合”状态。文章中使用的方法可以很容易地在体内检测阿尔茨海默病的大脑淀粉样蛋白β蛋白病理，并可能对常规诊断具有潜在价值。
Abstract
Alzheimer's disease is associated with the intraparenchymal growth of plaque-like amyloid deposits1–3. Amyloid plaques are formed by the progressive deposition and transformation of soluble amyloid β-protein monomers into insoluble and fibrillar aggregates that contain amyloid β-protein in a β-pleated sheet conformation. This process is described as ‘seeded polymerization’ of the monomers with slow-nucleation and fast-growth kinetics4. Soluble amyloid β-protein monomers are present in the cortical extracellular space and in the cerebrospinal fluid5,6, whereas insoluble aggregates so far can be found only by the examination of brain tissue by biopsy or autopsy. Here we present a biophysical method that uses the principle of seeded polymerization in combination with fluorescence correlation spectroscopy, which allowed us to detect single amyloid β-peptide aggregates in the cerebrospinal fluid samples from Alzheimer's patients. All of 15 Alzheimer's samples but none of the 19 age-matched control samples produced large peaks with fluorescence correlation spectroscopy indicating the rapid aggregation of the fluorescent labelled synthetic amyloid β-protein probe onto the amyloid β-protein ‘seeds’ present in the cerebrospinal fluid. Our method could enable easy in vivo detection of the cerebral amyloid β-protein pathology of Alzheimer's disease and might be of potential value to facilitate its routine diagnosis.
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