Mechanisms underlying glutamate dyshomeostasis in Alzheimer's disease

阿尔茨海默病谷氨酸稳态失调的机制

• 批准号: 10303751
• 负责人: PAUL ALLEN ROSENBERG
• 金额: $ 17.7万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10303751
• 关键词: Address; Aducanumab; Affect; Aging; Alzheimer' s Disease; Amyloid beta-Protein; Astrocytes; Biochemical; Biological Assay; Brain; Cell membrane; Clinical; Cytotoxin; Data; Defect; Dendritic Spines; Disadvantaged; Disease; Elements; Foundations; Functional disorder; GLAST Protein; Gene Expression Profile; Glutamate Transporter; Glutamates; Goals; Homeostasis; Homologous Gene; Human; Hyperactivity; Impaired cognition; Impairment; Intervention; Knock-out; Knockout Mice; Knowledge; Lead; Light; Long-Term Depression; Long-Term Potentiation; Mediating; Mitochondria; Modeling; Molecular; Monoclonal Antibodies; Neurons; Pathogenesis; Patients; Peptides; Play; Preparation; Presynaptic Terminals; Process; Production; Prosencephalon; Proteins; Publishing; Reporting; Rodent; Role; Slice; Synapses; Synaptosomes; Vesicle; Work; abeta oligomer; base; cell type; conditional knockout; experimental study; extracellular; insight; mitochondrial metabolism; mouse model; neuropathology; novel strategies; oAβ; prevent; proteoliposomes; reuptake; uptake

The critical neuropathology underlying the cognitive decline in Alzheimer's disease is the loss of synapses. A leading view of the pathogenesis of Alzheimer's disease is that synaptic abnormalities are produced that lead to enhanced synapse elimination. The synaptopathy in AD is thought to be due largely to the production of toxic soluble oligomers of the Aβ1-42 peptide (oAβ). Soluble Aβ oligomers, but not monomers, have been shown to cause synaptic dysfunction, manifest by inhibition of LTP, enhancement of LTD, loss of dendritic spines, biochemical abnormalities, and hyperactivity. The enhanced LTD and hyperactivity appear to be due to elevation of extracellular glutamate as a consequence of impaired glutamate reuptake. Although substantial evidence has accumulated to support this hypothesis, there are significant gaps in our understanding of how oAβ perturbs glutamate homeostasis. Specifically, the identity of the glutamate transporter or transporters targeted by oAβ to produce the defect in glutamate homeostasis is unknown, as are the molecular mechanisms by which glutamate transport function is compromised by oAβ. These gaps loom greater in light of recent evidence that monoclonal antibodies (aducanumab; BAN2401) targeting soluble Aβ oligomers in AD patients may slow cognitive decline. The major glutamate transporter in the forebrain is GLT- 1 (human homolog EAAT2), which represents 1% of brain protein. GLT-1 is expressed in both astrocytes and glutamatergic axon terminals. Recent work by the applicant using a conditional GLT-1 knockout (KO) has shown that GLT-1 expressed in axon terminals is the dominant transporter mediating glutamate uptake into crude synaptosome preparations, also known as plasma membrane vesicles (PMVs). GLT-1 expressed in presynaptic terminals has also been shown to play an important role in synaptic mitochondrial metabolism. Several studies suggest that in the human and in mouse models deficits in glutamate transporter expression and/or function occur in AD. In critical experiments, glutamate uptake into PMVs derived from brain slices was decreased when the slices were treated with oAβ, implicating neuronal GLT-1. The central hypothesis motivating this project is that GLT-1 is the primary mechanistic target of oAβ causing glutamate dyshomeostasis. Given these findings it is important to ascertain whether GLT-1 is the specific glutamate transporter targeted by oAβ, whether oAβ affects GLT-1 function in astrocytes or neurons, or both, and the molecular basis for the interaction of oAβ with GLT-1. The specific goals of this project are to: Aim 1: Identify the glutamate transporter whose function is impaired by oAβ. Aim 2: Determine the cellular localization of effects of oAβ on GLT-1 using a conditional GLT-1 KO. The pursuit of these goals will lead to a molecular understanding of how oAβ, the salient AD cytotoxins, perturb glutamate homeostasis in AD and ultimately lead to novel approaches to prevent and treat AD.

阿尔茨海默氏病认知能力下降的关键神经病理学是丧失 突触。阿尔茨海默氏病发病机理的主要视野是合成异常是 产生导致突触消除的增强。广告中的突触病被认为很大程度上是由于 Aβ1-42肽（OAβ）的有毒固体低聚物的产生。可溶性Aβ低聚物，但不是单体， 已证明会引起突触功能障碍，通过抑制LTP，LTD的抑制，损失 树突状刺，生化异常和多动症。增强的Ltd和多动症外观 尽管这是由于谷氨酸再摄取受损而升高细胞外谷氨酸。 积累了大量证据以支持这一假设，我们的差距很大 了解OAβ如何使谷氨酸稳态稳态。具体而言，谷氨酸的身份 OAβ靶向产生谷氨酸稳态缺陷的转运蛋白或转运蛋白尚不清楚， OAβ损害了谷氨酸转运功能的分子机制。这些差距迫在眉睫 据最近证明单克隆抗体（Aducanumab; BAN2401）的证据更大 AD患者的低聚物可能会减慢认知能力下降。前脑中的主要谷氨酸转运蛋白是GLT- 1（人类同源性EAAT2），代表脑蛋白的1％。 GLT-1在星形胶质细胞和 谷氨酸能轴突末端。申请人使用条件GLT-1敲除（KO）的最新工作已有 表明在轴突末端表达的GLT-1是介导谷氨酸摄取的主要转运蛋白 进入粗突触体制剂，也称为质膜蔬菜（PMV）。 GLT-1 在突触前末端表达的也已显示在突触线粒体中起重要作用 代谢。几项研究表明，在人类和小鼠模型中，定义了谷氨酸转运蛋白 AD中出现表达和/或功能。在关键实验中，谷氨酸摄取来自 当切片用OAβ，隐式神经元GLT-1处理时，脑切片会减少。中央 促使该项目的假设是GLT-1是OAβ引起谷氨酸的主要机械靶标 Dyshomeostasis。鉴于这些发现很重要，确定GLT-1是否是特定的谷氨酸 OAβ靶向的转运蛋白，无论OAβ是否影响星形胶质细胞或神经元中的GLT-1功能，或两者兼而有之 OAβ与GLT-1相互作用的分子基础。该项目的具体目标是： 目标1：确定其功能受到OAβ损害的谷氨酸转运蛋白。 AIM 2：使用条件GLT-1 KO确定OAβ对GLT-1的影响的细胞定位。 对这些目标的追求将导致对OAβ的分子理解，即显着的AD细胞毒素， AD中的捕获谷氨酸稳态，最终导致了预防和治疗AD的新方法。