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Mitochondrial-dependent Mechanisms of Apolipoprotein E Gene Expression in the Mammalian Brain

哺乳动物脑中载脂蛋白 E 基因表达的线粒体依赖性机制

基本信息

批准号：
10555222
负责人：
Meghan Elyse Wynne
金额：
$ 4.77万
依托单位：
EMORY UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-02-28 至 2024-02-27
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10555222
关键词：
Acceleration Acetyl Coenzyme A Address Alleles Alzheimer&apos s Disease Alzheimer&apos s disease model Alzheimer&apos s disease pathology Amyloid Amyloid beta-Protein Amyloid beta-Protein Precursor Apolipoprotein E Apolipoproteins Astrocytes Biochemical Bioenergetics Bioinformatics Brain Caregivers Categories Cause of Death Cell Separation Cells Cholesterol Cholesterol Homeostasis Citrates Cytoplasm DNA Sequence Alteration Data Dementia Disease Disease Progression Drosophila genus Enzymes Functional disorder Future Gene Dosage Gene Expression Genes Genetic Hippocampus Human Immunoassay Impaired cognition Knowledge Link Lipids Maintenance Measures Membrane Transport Proteins Memory Microglia Mitochondria Mitochondrial Proteins Modeling Modification Morphology Mus Mutant Strains Mice Mutation Neurofibrillary Tangles Neuroglia Neurons Oxidative Stress Pathogenesis Pathogenicity Pathologic Pathology Phenotype Play Polymerase Chain Reaction Prefrontal Cortex Production Protein Precursors Proteins Proteome Public Health Research Role SLC25A4 gene Source Sterols Synapses Testing Therapeutic Transgenic Mice United States Up-Regulation Visualization Western Blotting abeta accumulation alpha secretase apolipoprotein E-4 cell type citrate carrier cognitive function combat extracellular genetic risk factor hyperphosphorylated tau immunocytochemistry improved lipid metabolism lipidomics mitochondrial dysfunction mitochondrial membrane mitochondrial metabolism mouse model mutant neuron loss neurotoxic neurotransmission new therapeutic target protein expression response secretase tau Proteins therapeutic target therapeutically effective

项目摘要

PROJECT SUMMARY Alzheimer’s disease (AD) is a debilitating and common form of dementia, and a leading cause of death in the United States. Testing of the amyloid hypothesis has overwhelmingly been the focus of research on AD. According to this hypothesis, pathogenic processing of the Alzheimer’s precursor protein (APP) leads to accumulation of plaques containing amyloid beta that are a hallmark, and apparent cause, of AD. Despite much effort, research based on this hypothesis has yet to provide effective therapeutic targets for AD. Thus, alternative hypotheses invoking causal roles for mitochondria and metabolism of lipids and cholesterol in AD pathogenesis have also been proposed. While these hypotheses have been tested in relation to the amyloid hypothesis, a critical mechanistic gap remains in determining whether causal roles for mitochondria and cholesterol/lipid metabolism in AD pathogenesis may be linked with one another. A role for lipid and cholesterol metabolism in AD is supported by the fact that an allele of the ApolipoproteinE (ApoE) gene, encoding the primary carrier of lipids and cholesterol in the brain, is the strongest genetic risk factor for sporadic AD. In contrast, research examining causal roles for mitochondria in AD has focused on bioenergetics and oxidative stress, although mitochondria also play known roles in cholesterol and lipid metabolism. Whether mitochondria influence ApoE expression and/or cholesterol homeostasis in the context of AD remains unexplored and will be the focus of this proposal. Our preliminary data indicates that reduced expression of the mitochondrial membrane transporter SLC25A1 increases levels of ApoE and APP. SLC25A1 shuttles the metabolite citrate from mitochondria to the cytoplasm, where it gets converted to acetyl-CoA that is required for lipid and cholesterol synthesis. The central hypothesis that will be tested in this proposal is that genetic disruption of the SLC25A1 interactome (SLC25A1 and the network of proteins with which it physically interacts) drives increased ApoE expression and changes in cholesterol homeostasis, consequently impacting downstream APP production and processing. In Aim 1, the trainee will determine whether increased ApoE expression is a specific readout indicating dysfunction of components of the SLC25A1 interactome, or is instead a general response to mitochondrial dysfunction, using immunoblots, quantitative polymerase chain reaction (RT-qPCR), and lipidomics profiling in primary neurons and glia. In Aim 2, the trainee will determine whether Slc25a1 gene dosage modulates AD pathology in a mouse model of AD, using plate-based immunoassays and immunocytochemistry. Completion of these aims will reveal whether mitochondria contribute to AD pathogenesis through ApoE and/or cholesterol-dependent mechanisms, as well as whether this influence is specific to a certain hub of mitochondrial proteins involved in lipid/cholesterol metabolism. These findings will improve our understanding of mechanisms contributing to AD and suggest novel drug targets for this devastating disease.

项目摘要阿尔茨海默病（AD）是一种使人衰弱的常见痴呆形式，并且是老年人死亡的主要原因。美国的淀粉样蛋白假说的验证一直是AD研究的重点。根据这一假说，阿尔茨海默氏症前体蛋白（APP）的致病过程导致含有淀粉样蛋白β的斑块的积累是AD的标志和明显原因。尽管有许多然而，基于这一假设的研究尚未提供有效的AD治疗靶点。因此，替代线粒体和脂质及胆固醇代谢在AD发病机制中因果作用的假说也被提议。虽然这些假设已经与淀粉样蛋白假设进行了测试，在确定线粒体和胆固醇/脂质的因果作用是否代谢在AD发病机制中可能相互联系。脂质和胆固醇代谢在 AD由以下事实支持，即编码载脂蛋白E（ApoE）基因的主要载体的等位基因大脑中的脂质和胆固醇是散发性AD最强的遗传风险因素。相反，研究研究线粒体在AD中的因果作用主要集中在生物能量学和氧化应激，尽管线粒体还在胆固醇和脂质代谢中起已知的作用。线粒体是否影响ApoE 在AD的背景下，胆固醇表达和/或胆固醇稳态仍然未被探索，并且将是本发明的重点。提议我们的初步数据表明，线粒体膜转运蛋白的表达减少， SLC 25 A1增加ApoE和APP的水平。SLC 25 A1将代谢物柠檬酸盐从线粒体穿梭到线粒体。在细胞质中，它被转化为脂质和胆固醇合成所需的乙酰辅酶A。中央在该提议中将检验假设是SLC 25 A1相互作用组（SLC 25 A1）的遗传破坏以及与之发生物理相互作用的蛋白质网络）驱动ApoE表达增加，胆固醇稳态，从而影响下游APP生产和加工。在目标1中，受训者将确定增加的ApoE表达是否是指示以下功能障碍的特定读数： SLC 25 A1相互作用体的组成部分，或者是对线粒体功能障碍的一般反应，使用免疫印迹、定量聚合酶链反应（RT-qPCR）和原代神经元中的脂质组学分析，神经胶质。在目标2中，受训者将确定Slc 25 a1基因剂量是否调节小鼠中的AD病理学 AD模型，使用基于板的免疫测定和免疫细胞化学。这些目标的实现将揭示线粒体是否通过ApoE和/或胆固醇依赖性机制参与AD发病，以及这种影响是否是特定于涉及脂质/胆固醇的线粒体蛋白质的某个中心新陈代谢.这些发现将提高我们对AD机制的理解，并提出新的建议。针对这种毁灭性疾病的药物靶点。