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)，这一数字预计将在2010年翻一番 ~30年。AD的特征是失语症、精细运动和粗大运动功能的丧失以及认知能力的快速下降。 广为推崇的阿尔茨海默病“淀粉样假说”认为，阿尔茨海默病患者体内纤维淀粉样β蛋白(Aβ)斑块的积聚 脑实质推动了AD的发病。然而，淀粉样蛋白途径已被证明是无效的 在众多临床试验中的治疗目标和AD在临床上仍然难以解决，突出了迫切需要 以更深入地了解疾病的潜在机制。我们的实验室此前报告说 线粒体钙超载促进AD发病。细胞内钙动态平衡是通过 线粒体钙单转运体通道(MTCU)对mCa~(2+)摄取的调节 线粒体Na+/Ca~(2+)交换器(NCLX)。散发性阿尔茨海默病患者的大脑皮质显示-gt；70% NCLX表达下调。海马神经元特异性表达对线粒体钙外流的遗传挽救作用 Nclx对AD突变型患者线粒体钙超载、ROS应激、Aβ和tau沉积以及认知功能减退的保护作用 老鼠。我们将线粒体钙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)，以提高三磷酸腺苷的生物利用度。随着时间的推移，这种反应会转向 不适应，并促进病理性的线粒体钙超载。钙离子超载导致活性物质过量产生 氧物种(ROS)、代谢紊乱和细胞死亡，这些都是AD的特征。虽然是一个健壮的 神经元钙超载与阿尔茨海默病发病机制之间的联系已经建立，如何改变调节 MCa~(2+)摄取促进或预防AD病理的机制仍完全不清楚。我们的预赛 数据显示，在样本的多个皮质区域，MICU3的表达显著减少了~50% 从散发性AD患者中分离出。此外，MICU3在1岁龄的大脑皮层中的表达减少了90%。 3xTg-AD突变小鼠。这一建议假设神经元Micu3的丢失导致了异常 MTCU介导的线粒体钙摄取，导致线粒体钙超载，代谢紊乱，神经元功能障碍， AD时认知功能下降。为了解决这一假设，我们将利用新产生的神经元特异性MICU3 检测MICU3基因敲除是否足以导致神经退行性变。 随后，我们将使用我们新开发的可诱导Cre诱导的MICU3过表达小鼠系来观察 APPNL-G-F小鼠AD模型认知功能下降后恢复MICU3水平就足够了 减轻或逆转AD的病理改变。这些研究将通过一系列体外机制研究来跟进。 探讨MICU3介导的AD神经元功能障碍的分子机制。MICU3在人类免疫系统中的作用 生理和疾病状态，包括阿尔茨海默病，是未知的；再加上我们的发现改变了mCa2+的处理 是AD的病理特征和有希望的治疗靶点，为这一提议提供了强有力的理由。