Alpha-Synuclein-Metal Complexes and Oxidative Stress in Parkinson's Disease

描述（由申请人提供）：帕金森病（PD）是一种进行性神经退行性疾病，其特征在于疾病造成的大脑中多巴胺能神经元的逐渐丧失。退化多巴胺能细胞（路易体）中的主要内含物含有α-突触核蛋白（α-syn）蛋白的聚集体。PD患者多巴胺能细胞胞浆中Fe（III）浓度和脑脊液中Cu（II）含量均升高。氧化应激假说认为α-syn与氧化还原活性金属离子形成的络合物可以对神经细胞施加氧化应激，引起了广泛的关注。该提议的广泛的长期目标是使涉及α-顺式金属络合物和胞质物质（例如，多巴胺、谷胱甘肽和抗坏血酸）在氧化应激和损伤的发展中的作用。提出的研究背后的动机是，目前氧化应激假说的不一致主要源于缺乏对α-syn-金属络合物的氧化还原电位的了解以及对产生活性氧（ROS）的反应的详细了解。具体目的包括（1）研究Fe（III）和Cu（II）与野生型和突变体α-syn分子的结合以及所得络合物的氧化还原性质，（2）探测涉及这些α-syn-金属络合物的ROS产生反应的动力学，以及（3）在Fe（III）或Cu（II）存在下检查α-syn的聚集行为并评价所得聚集体的神经毒性。α-syn-金属络合物或含金属的α-syn聚集体在外源物质（例如，抗氧化剂如类黄酮或PD危险因素如除草剂）。各种分析技术（例如，NMR，EPR，伏安法，荧光和吸附光谱）将被用来研究结合和氧化还原反应，而原子力显微镜，圆二色性，和动态光散射将被用来跟踪聚集过程。 公共卫生相关性：该研究将提供深入了解Fe（III），Cu（II）和α-突触核蛋白在帕金森病（PD）病因学中可能发挥的作用。这些结果有望导致更好地了解相关的分子机制，其修改可能会预防或减轻PD的神经病理学效应。此外，鉴于所提出的技术多种多样，而且这一影响巨大的研究具有跨学科性质，这项工作将在为少数群体服务的机构培训下一代研究人员方面发挥重要作用。

DESCRIPTION (provided by applicant): Parkinson's disease (PD) is a progressive neurodegenerative disorder underscored by the gradual loss of dopaminergic neurons in disease-inflicted brains. The major inclusion in degenerating dopaminergic cells (Lewy bodies) contains aggregates of the a-synuclein (a-syn) protein. The Fe(III) concentration in the cytoplasm of dopaminergic cells and Cu(II) content in cerebral spinal fluid of PD patients are both elevated. The oxidative stress hypothesis, which contends that complexes formed between a-syn and redox active metal ions could impose oxidative stress on neuronal cells, has gained widespread attention. The broad, long-term objective of this proposal is to rationalize the various redox reactions involving a-syn-metal complexes and cytosolic species (e.g., dopamine, glutathione, and ascorbic acid) in the development of oxidative stress and damage. The motivation behind the proposed study is that the inconsistencies in the current oxidative stress hypothesis stem largely from the lack of knowledge of the redox potentials of the a-syn-metal complexes and a detailed understanding of the reactions that produce reactive oxygen species (ROS). The specific aims include (1) studying the binding of Fe(III) and Cu(II) to wild-type and mutant a-syn molecules and the redox properties of the resultant complexes, (2) probing the kinetics of the ROS-producing reactions that involve these a-syn-metal complexes, and (3) examining the aggregation behaviors of a-syn in the presence of Fe(III) or Cu(II) and evaluating the neurotoxicity of the resultant aggregates. The kinetic studies of the a-syn-metal complexes or metal-containing a-syn aggregates in the presence of exogenous species (e.g., antioxidants such as flavonoids or PD risk factors such as herbicides) will also be conducted. A variety of analytical techniques (e.g., NMR, EPR, voltammetry, fluorescence, and adsorption spectroscopy) will be used to investigate the binding and redox reactions, whereas atomic force microscopy, circular dichroism, and dynamic light scattering will be employed to follow the aggregation processes. PUBLIC HEALTH RELEVANCE: The study will provide insight into the possible roles played by Fe(III), Cu(II), and a-synuclein in the etiology of Parkinson's disease (PD). The results are expected to lead to a better understanding of the associated molecular mechanisms, the modification of which might prevent or alleviate the neuropathological effects of PD. Furthermore, given the variety of techniques proposed and the interdisciplinary nature of this high-impact research, the work will play a significant part in training the next generation of researchers at a minority-serving institution.