The Role of MICU3 in Alzheimer's Disease Pathogenesis

MICU3 在阿尔茨海默病发病机制中的作用

• 批准号: 10677454
• 负责人: Henry Cohen
• 金额: $ 3.34万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10677454
• 关键词: 1 year old; 3xTg-AD mouse; Ablation; Address; Affect; Aging; Agonist; Alzheimer' s Disease; Alzheimer' s disease model; Alzheimer' s disease pathology; Alzheimer' s disease patient; American; Amyloid; Amyloid beta-Protein; Aphasia; Biological Assay; Biological Availability; Brain; Calcium; Cell Death; Cell Line; Central Nervous System; Clinical; Clinical Trials; Cognitive deficits; Conceptions; Coupled; Cues; Data; Deposition; Development; Disease; Enterobacteria phage P1 Cre recombinase; Failure; Genes; Genetic; Genetic Predisposition to Disease; Glycolysis; Hippocampus; Histopathology; Homeostasis; Human; Impaired cognition; In Vitro; Intervention; Knock-out; Knockout Mice; Learning; Measures; Mediating; Membrane; Membrane Potentials; Memory; Metabolic; Mitochondria; Mitochondrial Swelling; Modeling; Molecular; Motor; Motor Activity; Mus; Mutant Strains Mice; Nerve Degeneration; Neurocognitive; Neurocognitive Deficit; Neuronal Dysfunction; Neurons; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Pathologic; Pathology; Pathway interactions; Phenotype; Physiology; Probability; Production; Prosencephalon; Protein Family; Reactive Oxygen Species; Regulation; Reporter; Reporting; Respiration; Role; Rotarod Performance Test; Rupture; Sampling; Series; Stress; Superoxides; Tamoxifen; Testing; Therapeutic; Time; aged; brain parenchyma; calcium uniporter; conditioned fear; constitutive expression; extracellular; follow-up; human old age (65+); inducible Cre; mitochondrial membrane; mitochondrial metabolism; mouse model; mutant; neuromuscular; neuron loss; overexpression; ratiometric; response; targeted treatment; tau Proteins; therapeutic target; therapeutically effective; uptake

PROJECT ABSTRACT 6.2M Americans over the age of 65 suffer from Alzheimer’s disease (AD) and this number expected to double in ~30 years. AD is characterized by aphasia, loss of fine and gross motor function, and rapid cognitive decline. The widely favored “amyloid hypothesis” of AD posits that accumulation of fibrillar amyloid beta (Aβ) plaques in the brain parenchyma drives AD pathogenesis. However, the amyloid pathway has proven to be an ineffective therapeutic target in numerous clinical trials and AD remains clinically intractable, highlighting the urgent need for deeper understanding of the underlying mechanisms of disease. Our lab previously reported that mitochondrial calcium (mCa2+) overload promotes AD pathogenesis. mCa2+ homeostasis is maintained through regulation of mCa2+ uptake through the mitochondrial calcium uniporter channel (mtCU) and mCa2+ efflux through the mitochondrial Na+/Ca2+ exchanger (NCLX). Human cortex from sporadic AD patients demonstrates >70% reduction in NCLX expression. Genetic rescue of mCa2+ efflux via hippocampal neuron-specific expression of NCLX protects against mCa2+ overload, ROS-stress, Aβ and tau deposition, and cognitive decline in AD mutant mice. We interpret remodeling of mCa2+ transport as a compensatory response to an early pathologic stress (e.g., energetic crisis, aging, genetic predisposition) to increase ATP bioavailability. Over time, this response turns maladaptive and promotes pathologic mCa2+ overload. mCa2+ overload causes excessive production of reactive oxygen species (ROS), metabolic derangement, and cell death, all hallmarks of AD. Although a robust connection between neuronal mCa2+ overload and AD pathogenesis has been established, how altered regulation of mCa2+ uptake promotes or protects against AD pathology remains completely unexplored. Our preliminary data demonstrates MICU3 expression is significantly reduced by ~50% in multiple cortical regions of samples isolated from sporadic AD patients. Further, MICU3 expression is reduced >90% in the cortex of 1 year-old. 3xTg-AD mutant mice. This proposal hypothesizes that loss of neuronal Micu3 contributes to aberrant mtCU-mediated mCa2+ uptake, resulting in mCa2+ overload, metabolic derangement, neuronal dysfunction, and cognitive decline in AD. To address this hypothesis we will utilize newly generated neuron-specific MICU3 knockout mouse lines to measure if knockout of MICU3 alone is sufficient to cause neurodegeneration. Subsequently, we will use our newly developed cre-inducible MICU3 overexpression mouse line to see if rescuing MICU3 levels shortly after onset of cognitive decline in the APPNL-G-F mouse model of AD is sufficient to mitigate or reverse AD pathology. These studies will be followed up with a series of mechanistic in vitro studies to determine the molecular mechanism of MICU3-mediated neuronal dysfunction in AD. The role of MICU3 in physiology and disease states, including AD, is unknown; coupled with our findings that altered mCa2+ handling is a pathologic feature of and promising therapeutic target for AD provides strong rationale for this proposal.

项目摘要 620万65岁以上的美国人患有阿尔茨海默病（AD），预计这一数字将在2015年翻一番。 ~30年。AD的特征在于失语、精细和粗大运动功能的丧失以及快速认知下降。 广泛支持的AD“淀粉样蛋白假说”认为，纤维状淀粉样蛋白β（Aβ）斑块的积累与AD的发生有关。 脑实质驱动AD发病。然而，淀粉样蛋白途径已被证明是无效的 众多临床试验中的治疗目标和AD在临床上仍然难以解决，凸显了迫切的需求 更深入地了解疾病的潜在机制。我们的实验室先前报告说， 线粒体钙超载促进AD发病。mCa 2+稳态通过以下方式维持： 通过线粒体钙单向转运体通道（mtCU）调节mCa 2+摄取和通过线粒体膜电位调节mCa 2+流出 线粒体Na+/Ca ~（2+）交换器（NCLX）。来自散发性AD患者的人皮质显示>70% 减少NCLX表达。通过海马神经元特异性表达 NCLX对AD突变体中mCa 2+超载、ROS应激、Aβ和tau沉积以及认知功能下降的保护作用 小鼠我们将mCa 2+转运的重塑解释为对早期病理应激的代偿反应（例如， 能量危机、衰老、遗传易感性）以增加ATP生物利用度。随着时间的推移，这种反应 适应不良并促进病理性mCa 2+过载。mCa 2+超载导致反应性 氧物质（ROS）、代谢紊乱和细胞死亡，所有这些都是AD的标志。虽然一个强大的 神经元mCa 2+超载和AD发病机制之间的联系已经建立，如何改变调节 mCa 2+摄入促进或保护AD病理学的作用仍然完全未被探索。我们的初步 数据表明，在样品的多个皮质区域中，MICU 3表达显著降低~ 50 分离自散发性AD患者。此外，MICU 3表达在1岁的皮质中减少>90%。 3xTg-AD突变小鼠。该提案假设神经元Micu 3的缺失导致了异常的 mtCU介导的mCa 2+摄取，导致mCa 2+过载、代谢紊乱、神经元功能障碍， 和认知能力的下降。为了解决这一假设，我们将利用新产生的神经元特异性MICU 3 敲除小鼠系以测量单独的MICU 3敲除是否足以引起神经变性。 随后，我们将使用我们新开发的cre诱导的MICU 3过表达小鼠系，看看是否 在AD的APPNL-G-F小鼠模型中，在认知下降发作后不久挽救MICU 3水平是足够的 以减轻或逆转AD病理。这些研究将随后进行一系列的体外机制研究 以确定AD中MICU 3介导的神经元功能障碍的分子机制。MICU 3在以下方面的作用： 生理学和疾病状态，包括AD，是未知的;加上我们的发现，改变mCa 2+处理 是AD的一个病理特征和有希望的治疗靶点，这为该建议提供了强有力的理论基础。