Understanding the Molecular Origins of the Toxicity of Alpha-synuclein in Parkinson's Disease

帕金森病（PD）是一种进行性神经退行性疾病，困扰着全球65岁以上人口的2%。通常认为PD的标志是人α-突触核蛋白（一种突触前140个残基的蛋白质）的不溶性原纤维在路易体中的沉积。也有重要的遗传学证据表明，α-突触核蛋白在PD的发病机制，与点突变（A30 P，E46 K，H50 Q，G51 D和A53 T）和已知导致显性遗传早发性PD的基因三重化。该提案将对前原纤维α-突触核蛋白寡聚体毒性的结构基础获得结论性理解，它们通常被认为是PD病因学中毒性最大的物种。由于这些蛋白质状态的瞬时性质，这是一个与重大实验和理论挑战相关的最高目标。事实上，目前对α-突触核蛋白寡聚体的性质，包括其毒性的结构和分子基础的了解很少，我们认为我们的研究提案来得正是时候，因为我们现在拥有进行此类研究的所有工具。我们的目标是通过表征和比较具有相似形态但显著不同毒性水平的两种类型的前原纤维寡聚体的结构性质来揭示α-突触核蛋白寡聚体的细胞毒性的分子基础（Cremades等人Cell，2012，149：1048-59）。通过使用溶液和固态核磁共振（NMR）光谱与计算生物学相结合，我们将确定这些低聚物的结构特性，并研究它们与生物脂质膜选择性相互作用的起源。我们的分析将扩展到病理突变体的α-突触核蛋白，并将补充生物物理和细胞实验。α-突触核蛋白寡聚体/膜相互作用的分子基础的目标跨学科表征将对研究淀粉样蛋白疾病（包括帕金森氏症、阿尔茨海默氏症和II型糖尿病）的分子基础的更广泛的学术界和更广泛的学科（例如蛋白质科学、生物化学、NMR光谱学、分子模拟、细胞和分子生物物理学）产生重大影响。预计这项研究的结果可能直接转化为知识，导致帕金森病和其他淀粉样蛋白相关疾病的新治疗方法。

Parkinson's disease (PD) is a progressive neurodegenerative disorder afflicting 2% of the global population over 65 years of age. It is generally recognised that the hallmark of PD is the deposition of insoluble fibrils of human alpha-synuclein, a pre-synaptic 140-residue protein, in Lewy bodies. There is also significant genetic evidence implicating alpha-synuclein in the pathogenesis of PD, with point mutations (A30P, E46K, H50Q, G51D and A53T) and gene triplication known to cause dominantly inherited early onset PD.The proposal will achieve a conclusive understanding of the structural bases of the toxicity of prefibrilar alpha-synuclein oligomers, which are generally acknowledged to be the most toxic species in the aetiology of PD. This is a top goal that is associated with significant experimental and theoretical challenges owing to the transient nature of these protein states. Indeed, there is currently a poor understanding of the nature of alpha-synuclein oligomers, including the structural and molecular bases of their toxicity.We believe that our research proposal comes at a most opportune time, since we now have all the tools to perform such a study. Our goal is to unveil the molecular bases of the cellular toxicity of alpha-synuclein oligomers by characterising and comparing the structural properties of two types of pre-fibrilar oligomers having similar morphologies but significantly different levels of toxicity (Cremades et al Cell, 2012, 149:1048-59). By using solution and solid-state nuclear magnetic resonance (NMR) spectroscopy in combination with computational biology, we will determine the structural properties of these oligomers and investigate the origins of their selective interaction with biological lipid membranes. Our analysis will be extended to pathological mutants of alpha-synuclein and will be complemented by biophysical and cellular experiments. The aimed interdisciplinary characterisation of the molecular bases of alpha-synuclein oligomers/membrane interactions will have significant impact on the wider academic community studying the molecular bases of amyloid diseases (including Parkinson's, Alzheimer's and Diabetes type II) and wider disciplines such as protein science, biochemistry, NMR spectroscopy, molecular simulations, cellular and molecular biophysics. It is anticipated that the outcomes of this research may directly translate into knowledge leading to new therapeutic approaches in Parkinson's disease and other amyloid-associated disorders.