Alpha-Synuclein, PUFA and Membrane Vesicles in Health and Parkinson's Disease

α-突触核蛋白、PUFA 和膜囊泡在健康和帕金森病中的作用

• 批准号: 7345401
• 负责人: DENNIS J SELKOE
• 金额: $ 30.83万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-01-15 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7345401
• 关键词: Affect; Anabolism; Apolipoproteins; Binding; Biochemical; Biological Assay; Biological Models; Brain; Brain region; Cells; Corpus striatum structure; Cytoplasm; Dopaminergic Cell; Drosophila genus; Dyes; Enzymes; Exposure to; FM1 43; Family; Fatty Acids; Functional disorder; Genetic Screening; Goals; Grant; Health; Hereditary Disease; Human; Knockout Mice; Lewy Bodies; Life; Light; Lipid Binding; Lipids; Membrane; Membrane Fluidity; Membrane Protein Traffic; Membrane Structure and Function; Molecular; Mus; Neurites; Neurodegenerative Disorders; Neurons; Parkinson Disease; Phospholipase D; Phospholipids; Physiology; Population; Principal Investigator; Process; Property; Protein Overexpression; Proteins; Rate; Regulation; Role; Series; Solubility; Structure; Synaptosomes; Therapeutic; Vesicle; Yeasts; Zellweger Syndrome; alpha synuclein; aqueous; base; brain cell; dimer; dopaminergic neuron; fatty acid binding protein; fatty acid oxidation; fatty acid-binding proteins; in vivo; inhibitor/antagonist; insight; lipid metabolism; monomer; mouse model; novel; synuclein

DESCRIPTION (provided by applicant): Parkinson's disease, the second most common neurodegenerative disorder, is marked by progressive dysfunction and loss of nigral dopaminergic neurons. This cardinal feature is accompanied by the accumulation of protein inclusions in dopaminergic neurons and their processes (Lewy bodies and neurites), the major constituent of which is a-synuclein (aS). aS has 7 repeats resembling the lipid-binding a-helical domains of apolipoproteins, and its binding to phospholipid membranes markedly alters its secondary structure. We have recently: a) discovered homologies of aS with the fatty acid (FA) binding protein (FABP) family; b) found that pure aS binds free FAs reversibly; c) detected a pool of highly soluble, lipid-associated aS oligomers in dopaminergic cells, normal mouse and human brains and, at elevated levels, in PD and DLB brains; d) shown that exposure of living mesencephalic neurons to polyunsaturated FAs enhances ~ and to saturated FAs retards ~ the formation of soluble aS oligomers; and e) documented increased endogenous PUFA levels and membrane fluidity in aS-overexpressing neurons, and the opposite in aS knock-out mice. Based on these findings, we hypothesize that aS normally interacts with FAs in both the aqueous and membrane-phospholipid compartments of the cytoplasm and helps regulate aspects of lipid composition (particularly PUFA content) and thus membrane properties, and that aS-FA interactions help regulate the oligomerization of aS and can thus initiate aS assembly into first soluble and then insoluble oligomers. To pursue this molecular hypothesis about aS function and dysfunction, we now propose a series of interrelated goals. 1) To attempt to prove that altering endogenous PUFA levels (e.g., lowered in cells treated with a A6 desaturase inhibitor or elevated in mice modeling Zellweger's syndrome) induces corresponding decreases or increases in endogenous aS oligomers in brain cells. 2). To examine the effects of aS-FA interactions on the formation, ultrastructure and biophysical properties of membrane vesicles in living cells. 3) To ascertain whether and how PUFA-ctS interactions affect the one discrete biochemical function of aS documented to date: inhibiting Phospholipase D. Our focus on a key role for aS in lipid metabolism and membrane vesicle formation/stability derives from a novel set of observations made by the two principal investigators. Moreover, it is strongly supported by recent unbiased genetic screens in aS-expressing yeast or Drosophila that implicated a function of aS in lipid regulation and membrane trafficking. New findings emanating from this grant should simultaneously shed light on the physiology of aS and the earliest steps in its pathological oligomerization, with attendant therapeutic insights.

描述（由申请人提供）：帕金森氏病是第二个最常见的神经退行性疾病，其标志性是进行性功能障碍和非洲多巴胺能神经元的丧失。这种基本特征伴随着蛋白质夹杂物在多巴胺能神经元及其过程（Lewy身体和神经突）中的积累，其主要成分是A-突触核蛋白（AS）。 AS 7重复类似于载脂蛋白的脂质结合A螺旋结构域，并且与磷脂膜的结合显着改变了其二级结构。我们最近有：a）与脂肪酸（FA）结合蛋白（FABP）家族的AS发现的同源性； b）发现纯净的自由fas可逆地绑定； c）检测到多巴胺能细胞，正常小鼠和人脑中的高度可溶的，脂质相关的池，在PD和DLB大脑中升高； d）表明，活着的脑脑神经元暴露于多不饱和FAS增强〜和饱和的Fas降低〜溶解性的寡聚物的形成； E）记录了过表达神经元中内源性PUFA水平和膜流动性的提高，而AS敲除小鼠相反。基于这些发现，我们假设，随着通常与FAS在细胞质的水性和膜 - 磷脂室中相互作用，有助于调节脂质组成的各个方面（尤其是PUFA含量）（尤其是PUFA含量），从而有助于AS-FA相互作用，并有助于调节AS-FA的相互作用。因此，AS的寡聚化可以作为组装启动到第一个可溶性，然后将其启动到不溶性的低聚物中。为了追求有关功能和功能障碍的分子假设，我们现在提出了一系列相互关联的目标。 1）试图证明改变内源性PUFA水平（例如，在用A6去饱和酶抑制剂治疗的细胞中降低或在对Zellweger综合征建模的小鼠中升高）会诱导相应的降低或增加的内源性降低或增加为脑细胞的内源性。 2）。检查AS-FA相互作用对活细胞中膜囊泡的形成，超微结构和生物物理特性的影响。 3）确定pufa-cts相互作用是否以及如何影响迄今为止记录的一种离散的生化功能：抑制磷脂酶D.我们对脂质代谢和膜囊泡形成/稳定性的关注关注的重点来自一组新颖两位主要研究人员的观察结果。此外，在表达酵母或果蝇表达的近期无偏基因筛选中，这表明了AS在脂质调节和膜运输中的功能。从这笔赠款中提出的新发现应该同时阐明其病理性寡聚化的AS生理和最早的步骤，并具有随之而来的治疗见解。