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RICTOR dependent microglial polarization in aging

衰老过程中 RICTOR 依赖性小胶质细胞极化

基本信息

批准号：
9914199
负责人：
Amadu Jalloh
金额：
$ 6.78万
依托单位：
UNIVERSITY OF SOUTH FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-15 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9914199
关键词：
Age Aging Alleles Alzheimer&apos s Disease Anti-Inflammatory Agents Back Behavior Behavioral Bioinformatics Biological Biological Assay Biology Brain Breeding Cells Cessation of life Chemotaxis Chronic Cognition Cognitive Cognitive deficits Computer software Cues Data Set Disease Exons Functional disorder Genes Goals Homeostasis Immune Immune System Diseases Immunohistochemistry Impaired cognition Impairment Inflammation Inflammation Mediators Inflammatory Knock-out Knockout Mice Knowledge Learning LoxP-flanked allele Mass Spectrum Analysis Measures Mediating Memory Metabolism Microglia Molecular Motor Activity Mus Nerve Degeneration Neurodegenerative Disorders Neuroimmune system Neurologic Neuronal Plasticity Organism Parkinson Disease Pathogenesis Pathology Pathway Analysis Pathway interactions Performance Phagocytosis Phenotype Physiological Play Predisposition Prevention Process Proteins Proteomics Publishing Radial Regulation Risk Factors Rodent Role Rotarod Performance Test Signal Pathway Signal Transduction Site Stimulus Tamoxifen Western Blotting age related age related neurodegeneration aged aging brain aging population arm base brain tissue cognitive ability conditioned fear cytotoxic differential expression effective therapy experience experimental study field study functional mimics in vivo knock-down knockout animal macrophage neurogenesis neuroinflammation neuropathology neurotoxic novel object recognition offspring prevent promoter resilience response targeted treatment therapy development tissue repair water maze

项目摘要

Aging is the primary risk factor for most neurodegenerative disorders including Alzheimer's disease (AD). The dysfunction seen in organisms because of aging has a multifaceted origin at the molecular level. Understanding how altered molecular signaling in key cellular pathways generates age-related decline is essential to develop better, more targeted therapies that ameliorate dysfunction. AD and related diseases are the most crippling cognitive threat to our aging population. There is no cure for AD, and this is partly due to a poor understanding of how aging and inflammation impact pathogenesis and neural plasticity. It is imperative that we gain a more comprehensive understanding of the biological basis for brain aging. We hypothesize that the neuroimmune system plays a critical role in aging pathology. Microglia are the brain's resident macrophage and the major immune effector in the CNS. “Activated” microglia assume a pro-inflammatory phenotype, secreting cytotoxic factors. An additional process mediated by anti-inflammatory molecules, inhibits the pro- inflammatory phenotype and shifts microglial toward a restorative phenotype that promotes debris clearance and tissue repair. Aging perturbs microglial biology such that aging microglia become hyper-responsive to pro- inflammatory stimuli, generate excess cytotoxic factors, and become insensitive to anti-inflammatory molecules. Aged microglia are also increasingly unable to assume an anti-inflammatory phenotype. In this way, dysfunctional microglia become neurotoxic and increase CNS vulnerability. We have previously described age- related changes in rodent microglia using mass-spectrometry-based proteomics. We identified RICTOR, a subunit of mTORC2, as an upstream regulator predicted to be inhibited with age. This prediction coincided with upregulated pro-inflammatory signaling, downregulated anti-inflammatory signaling, and impaired cellular metabolism and energy regulation. We validated this finding by demonstrating reduced RICTOR expression in aged primary mouse microglia when compared with their younger counterparts. We also conducted targeted knockdown of RICTOR in BV2 cells and observed a phenotype resembling aged microglia, validating a primary role for RICTOR in the aging phenotype. The present study will determine the consequences of RICTOR knockdown in vivo on microglial phenotype and cognitive behavior in young mice. We hypothesize that in vivo microglial RICTOR deletion will induce an aging microglial phenotype that will decrease brain resilience and have widespread impact on cognition and neural plasticity. We predict that knockout animals will manifest a phenotype characterized by dysregulated neuroinflammation, impaired cognitive and behavioral performance, and reduced brain plasticity. Our goal is to identify the molecular substrates of in vivo microglial dysfunction via mTORC2 signaling with the experiments detailed in the proposal.

衰老是包括阿尔茨海默病（AD）在内的大多数神经退行性疾病的主要风险因素。的由于衰老而在生物体中看到的功能障碍在分子水平上具有多方面的起源。了解关键细胞通路中改变的分子信号传导如何产生与年龄相关的衰退，开发更好、更有针对性的治疗方法来改善功能障碍至关重要。AD及相关疾病对我们老龄化人口最严重的认知威胁。没有治愈AD，这部分是由于对衰老和炎症如何影响发病机制和神经可塑性的理解不足。势在必行我们对大脑衰老的生物学基础有了更全面的了解。我们假设神经免疫系统在衰老病理学中发挥着关键作用。小胶质细胞是大脑的常驻巨噬细胞也是中枢神经系统中的主要免疫效应子。"活化的"小胶质细胞呈现促炎表型，分泌细胞毒因子。另外一个由抗炎分子介导的过程，抑制了促炎性细胞因子，炎症表型，并将小胶质细胞转变为促进碎片清除的恢复表型和组织修复。衰老扰乱了小胶质细胞生物学，使得衰老的小胶质细胞变得对前体细胞过度敏感。炎症刺激，产生过量的细胞毒性因子，并变得对抗炎不敏感分子。老化的小胶质细胞也越来越不能呈现抗炎表型。通过这种方式，功能障碍的小胶质细胞变得神经毒性并增加CNS脆弱性。我们以前描述过年龄- 使用基于质谱的蛋白质组学研究啮齿动物小胶质细胞的相关变化。我们确定了RICTOR，亚基mTORC2，作为上游调节预测被抑制随着年龄的增长。这一预测与上调促炎信号传导，下调抗炎信号传导，以及受损的细胞凋亡。代谢和能量调节。我们证实了这一发现，证明减少RICTOR表达，老年小鼠初级小胶质细胞与年轻小鼠相比。我们还针对在BV2细胞中敲低RICTOR，并观察到类似于老年小胶质细胞的表型，验证了一个主要的 RICTOR在衰老表型中的作用。本研究将确定RICTOR的后果体内敲低对幼龄小鼠小胶质细胞表型和认知行为的影响。我们假设在体内小胶质细胞RICTOR缺失将诱导老化的小胶质细胞表型，这将降低脑弹性，对认知和神经可塑性有着广泛的影响。我们预测，敲除动物将表现出以神经炎症失调、认知和行为表现受损为特征的表型，大脑可塑性降低我们的目标是确定体内小胶质细胞功能障碍的分子底物通过mTORC2信号与实验中详细的建议。