Acceleration of oligomerization, not fibrillization, is a shared property of both α-synuclein mutations linked to early-onset Parkinson's disease:: Implications for pathogenesis and therapy
Acceleration of oligomerization, not fibrillization, is a shared property of both α-synuclein mutations linked to early-onset Parkinson's disease:: Implications for pathogenesis and therapy
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DOI：
10.1073/pnas.97.2.571
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发表时间：
2000-01-18
影响因子：
11.1
通讯作者：
Lansbury, PT
中科院分区：
文献类型：
--
作者：
Conway, KA;Lee, SJ;Lansbury, PT
帕金森病(PD)黑质的特征是含有纤维样α-突触核蛋白的路易小体的存在。早发性骨质疏松症与编码α-突触核蛋白的基因的两个点突变有关，这表明疾病可能是由于加速纤维化而引起的。然而，致病物种的同一性及其与α-突触核蛋白原纤维的关系尚未阐明。在这项体外研究中，比较了野生型(WT)蛋白和两种突变蛋白以及可能模拟杂合型PD患者的等摩尔混合物的单体α-突触核蛋白的消失率和纤维状α-突触核蛋白的出现速度。而其中一个突变蛋白(A53T)和A53T和WT的等摩尔混合物的纤化速度比WTα-突触核蛋白快，而另一个(A30P)和相应的与WT的等摩尔混合物的纤化速度慢。然而，在最终产生纤维的条件下，A30P单体的消耗速度与WT单体相当或略快，而A53T的消耗速度甚至更快。这些趋势之间的差异表明存在非纤维α-突触核蛋白低聚物，其中一些是通过沉淀和凝胶过滤层析从纤维和单体α-突触核蛋白中分离出来的。原子力显微镜可将球体(高度范围2-6 nm)、球链(原纤维)和环状原纤维(高度约4 nm)与原纤维(高度约8 nm)区分开来。重要的是，抑制α-突触核蛋白纤化但不阻止其寡聚的候选药物可以模仿A30P突变，从而可能加速疾病进展。
The Parkinson's disease (PD) substantia nigra is characterized by the presence of Lewy bodies containing fibrillar alpha-synuclein. Early-onset Po has been linked to two point mutations in the gene that encodes alpha-synuclein, suggesting that disease may arise from accelerated fibrillization. However, the identity of the pathogenic species and its relationship to the alpha-synuclein fibril has not been elucidated. In this in vitro study, the rates of disappearance of monomeric alpha-synuclein and appearance of fibrillar alpha-synuclein were compared for the wild-type (WT) and two mutant proteins, as well as equimolar mixtures that may model the heterozygous PD patients. Whereas one of the mutant proteins (A53T) and an equimolar mixture of A53T and WT fibrillized more rapidly than WT alpha-synuclein, the other (A30P) and the corresponding equimolar mixture with WT fibrillized more slowly. However, under conditions that ultimately produced fibrils, the A30P monomer was consumed at a comparable rate or slightly more rapidly than the WT monomer, whereas A53T was consumed even more rapidly. The difference between these trends suggested the existence of nonfibrillar alpha-synuclein oligomers, some of which were separated from fibrillar and monomeric alpha-synuclein by sedimentation followed by gel-filtration chromatography. Spheres (range of heights: 2-6 nm), chains of spheres (protofibrils), and rings resembling circularized protofibrils (height: ca. 4 nm) were distinguished from fibrils (height: ca. 8 nm) by atomic force microscopy. Importantly, drug candidates that inhibit alpha-synuclein fibrillization but do not block its oligomerization could mimic the A30P mutation and thus may accelerate disease progression.