Biochemical and morphological classification of disease-associated alpha-synuclein mutants aggregates.
Biochemical and morphological classification of disease-associated alpha-synuclein mutants aggregates.
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DOI：
10.1016/j.bbrc.2018.11.200
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发表时间：
2019-01
影响因子：
3.1
通讯作者：
G. Tanaka;T. Yamanaka;Y. Furukawa;N. Kajimura;K. Mitsuoka;N. Nukina
中科院分区：
文献类型：
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作者：
G. Tanaka;T. Yamanaka;Y. Furukawa;N. Kajimura;K. Mitsuoka;N. Nukina
脑内α-突触核蛋白(a-syn)聚集与多种突触核病有关，包括帕金森病(PD)、路易体痴呆(DLB)和多系统萎缩(MSA)。到目前为止，已知至少有六种与a-syn相关的疾病突变(即A30P、E46K、H50Q、G51D、A53T和A53E)会导致以遗传性为主的家族性突触核病。以前使用重组蛋白的研究已经报道，与野生型(WT)相比，与疾病相关的突变体的子集显示出更高的聚集倾向，并形成光谱上可区分的聚集体。然而，尚未对所有与疾病相关的a-syn突变体的聚集体进行形态和生化比较。在本研究中，我们进行了电子显微镜检查、盐酸胍(GdnHCl)变性和蛋白酶消化，以从各自的点突变中对聚集体进行分类。在电子显微镜下，我们观察到α-syn突变体聚集体中淀粉样纤维形态的变化，主要分为两类：WT和E46K突变体中观察到的扭曲纤维，而其他突变体中观察到的直纤维。GdnHCl变性实验表明，除E46K外，a-syn突变体的抗变性能力均强于WT。经酶处理的聚集体的质谱分析显示，有多种抗酶核心，这可能与它们的形态特征相对应。它们的不同性质可能与具有这些突变的并核病的临床病理差异有关。
Alpha-synuclein (a-syn) aggregation in brain is implicated in several synucleinopathies, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Until date, at least six disease-associated mutations in a-syn (namely A30P, E46K, H50Q, G51D, A53T, and A53E) are known to cause dominantly inherited familial forms of synucleinopathies. Previous studies using recombinant proteins have reported that a subset of disease-associated mutants show higher aggregation propensities and form spectroscopically distinguishable aggregates compared to wild-type (WT). However, morphological and biochemical comparison of the aggregates for all disease-associated a-syn mutants have not yet been performed. In this study, we performed electron microscopic examination, guanidinium hydrochloride (GdnHCl) denaturation, and protease digestion to classify the aggregates from their respective point mutations. Using electron microscopy we observed variations of amyloid fibrillar morphologies among the aggregates of a-syn mutants, mainly categorized into two groups: twisted fibrils observed for both WT and E46K while straight fibrils for the other mutants. GdnHCl denaturation experiments revealed the a-syn mutants except for E46K were more resistant than WT against the denaturation. Mass spectrometry analysis of protease-treated aggregates showed a variety of protease-resistant cores, which may correspond to their morphological properties. The difference of their properties could be implicated in the clinicopathological difference of synucleinopathies with those mutations.