PDF(Pubmed)
Abstract：
Human neurodegenerative diseases associated with the misfolding of the alpha-synuclein (aS) protein (synucleinopathies) are similar to prion diseases to the extent that lesions are spread by similar molecular mechanisms. In a transgenic mouse model (M83) overexpressing a mutated (A53T) form of human aS, we had previously found that Protein Misfolding Cyclic Amplification (PMCA) triggered the aggregation of aS, which is associated with a high resistance to the proteinase K (PK) digestion of both human and murine aS, a major hallmark of the disease-associated prion protein. In addition, PMCA was also able to trigger the aggregation of murine aS in C57Bl/6 mouse brains after seeding with sick M83 mouse brains. Here, we show that intracerebral inoculations of M83 mice with C57Bl/6-PMCA samples strikingly shortens the incubation period before the typical paralysis that develops in this transgenic model, demonstrating the pathogenicity of PMCA-aggregated murine aS. In the hind brain regions of these sick M83 mice containing lesions with an accumulation of aS phosphorylated at serine 129, aS also showed a high PK resistance in the N-terminal part of the protein. In contrast to M83 mice, old APPxM83 mice co-expressing human mutated amyloid precursor and presenilin 1 proteins were seen to have an aggregation of aS, especially in the cerebral cortex, hippocampus and striatum, which also contained the highest load of aS phosphorylated at serine 129. This was proven by three techniques: a Western blot analysis of PK-resistant aS; an ELISA detection of aS aggregates; or the identification of aggregates of aS using immunohistochemical analyses of cytoplasmic/neuritic aS deposits. The results obtained with the D37A6 antibody suggest a higher involvement of murine aS in APPxM83 mice than in M83 mice. Our study used novel tools for the molecular study of synucleinopathies, which highlight similarities with the molecular mechanisms involved in prion diseases.
摘要：
与α-突触核蛋白（aS）蛋白的错误折叠相关的人类神经退行性疾病（突触核蛋白病）与朊病毒疾病相似，其程度是病变通过相似的分子机制传播。在过表达人aS的突变（A53T）形式的转基因小鼠模型（M83）中，我们以前发现，蛋白质错误折叠循环扩增（PMCA）触发了aS的聚集，这与对人和鼠aS的蛋白酶K（PK）消化的高抗性有关，与疾病相关的朊病毒蛋白的主要标志。此外,在接种病态M83小鼠脑后,PMCA还能够在C57Bl/6小鼠脑中触发鼠aS的聚集。这里,我们表明，脑内接种M83小鼠C57Bl/6-PMCA样品显着缩短了典型瘫痪之前的潜伏期，在这个转基因模型中发展，证明了PMCA聚集的鼠aS的致病性。在这些患病的M83小鼠的后脑区域中，病变在丝氨酸129处磷酸化了aS的积累，aS在蛋白质的N末端部分也显示出高PK抗性。与M83小鼠相反，发现共表达人类突变淀粉样蛋白前体和早老素1蛋白的年老APPxM83小鼠具有aS的聚集，尤其是大脑皮层,海马和纹状体,其中还包含在丝氨酸129处磷酸化的aS的最高负荷。这通过三种技术得到了证明：PK抗性aS的Western印迹分析；aS聚集体的ELISA检测；或使用细胞质/神经质aS沉积物的免疫组织化学分析鉴定aS的聚集体。用D37A6抗体获得的结果表明鼠aS在APPxM83小鼠中比在M83小鼠中更高的参与。我们的研究使用新的工具进行突触核蛋白病的分子研究，这突出了与朊病毒疾病涉及的分子机制的相似性。
