Inflammatory Mechanisms Underlie Lysosome Failure in the Aging Brain

炎症机制是衰老大脑中溶酶体衰竭的基础

• 批准号: 10159817
• 负责人: Laura L Dugan
• 金额: $ 35.99万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-15 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10159817
• 关键词: Acids; Address; Adult; Age; Aging; Alkalinization; Alzheimer' s Disease; Alzheimer' s disease risk; American; Animals; Astrocytes; Autophagolysosome; Autophagosome; Brain; Cathepsins; Cell physiology; Cells; Cellular Structures; Centers for Disease Control and Prevention (U.S.); Chemicals; Chronic; Confocal Microscopy; Data; Dementia; Development; Disease; Elderly; Enzymes; Etiology; Event; Failure; Fiber; Genes; Glial Fibrillary Acidic Protein; Grant; Healthcare; Human; Image; Immune; Impairment; Induced pluripotent stem cell derived neurons; Inflammation; Inflammatory; Injury; Interleukin-6; Intervention; Laboratories; Lead; Link; Literature; Lysosomes; Mediating; Modification; Morphology; Mus; NADPH Oxidase; Natural Immunity; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Injury; Neurons; Organelles; Organism; Oxidation-Reduction; Parkinson Disease; Pathologic Processes; Peptide Hydrolases; Pharmacology; Process; Proteins; Proteolysis; Publishing; Recycling; Regulation; Reporting; Resolution; Risk; Risk Factors; Role; STAT3 gene; Scheme; Signal Transduction; Site; Synapses; Techniques; Testing; age related; age related neurodegeneration; aged; aging brain; alkalinity; base; brain health; cell injury; cytokine; effective intervention; effective therapy; fly; genetic approach; genome wide association study; human old age (65+); improved; in vivo; induced pluripotent stem cell; inhibitor/antagonist; insight; lysosomal proteins; mouse model; nervous system disorder; normal aging; novel; risk variant; vacuolar H+-ATPase

According to the Centers for Disease Control (CDC), 5 million Americans are living with Alzheimer's disease (AD), and another 2 million with Parkinson's disease (PD) and other late-onset neurodegenerative conditions (LO-NDs), yet to date, disease-modifying treatments for these diseases have remained elusive. While aging is the single greatest risk factor for LO-NDs, genome wide association studies (GWAS) have identified genes involved in regulation of lysosomes (vesicular organelles responsible for degrading and recycling damaged cellular material), and activation of inflammation and innate immunity, as LO-ND risk genes. However, to date, it is unclear how these two processes may interact in aging brain to promote the development of LO-NDs. Our data suggests that lysosomes may progressively fail during normal aging – even in the absence of a specific disease process or gene – and further suggest that low-grade induction of the innate immune enzyme, NADPH oxidase (Nox), by IL-6, may specifically result in lysosome failure in the aging brain. Exciting new data, below, shows that lysosomal failure in aging brain can be rescued by inhibition of Nox. Therefore based on recent literature, and our published and new observations, we propose that age-related lysosome failure is due to IL-6-mediated activation of NADPH oxidase, and propose mechanistic studies to test each component of this hypothesis. The premise behind this application, that inflammation in aging brain causes progressive failure of lysosomes, is supported by existing literature, our published studies, and new preliminary data, but has not been systematically studied. Aim 1 will test the hypothesis that lysosome failure during aging is due to inflammatory activation of Nox, and the corollary that Nox induction is mediated by Il-6 and STAT3 signaling. Our data showing that lysosomal function can be rescued by a Nox inhibitor in aging animals supports the first step in this hypothesis, and is to our knowledge the first to show that Nox inhibition can improve brain lysosome function. Unique mouse models, including PV-tdTomato, IL-6-/- and inducible neuronal Stat3-/- mice with high-resolution confocal microscopy will be used. Aim 2 will determine mechanistically how inflammation produces lysosome failure and impaired degradation of cargo in aging brain. Induced pluripotent stem cell (iPSC)-derived human neurons (iPSC-huNs), and aged mice treated with Nox-modifying agents will determine mechanisms impairing lysosome function. Aim 3 tests the hypotheses that extruded lysosomal cargo contains active proteases which then damage nearby cells including neurons, and that extruded lysosomal material (cargo) is pro-inflammatory. Imaging of cathepsin activity, neuronal injury and markers of microglial and astrocyte activation will be employed. IMPACT: Age-related diseases of the nervous system are an ever-increasing health care issue, but no disease-modifying treatments have emerged for these diseases. This proposal will advance our understanding of how inflammation impairs the ability of lysosomes to clear and recycle damaged cellular material to provide new treatment targets for neurodegenerative disorders.

根据疾病控制中心 (CDC) 的数据，500 万美国人患有阿尔茨海默病 (AD)，另有 200 万人患有帕金森病 (PD) 和其他迟发性神经退行性疾病 (LO-ND)，迄今为止，针对这些疾病的疾病缓解疗法仍然难以捉摸。虽然衰老是 全基因组关联研究 (GWAS) 已确定了 LO-ND 的单一最大风险因素 参与溶酶体（负责降解和回收受损细胞的囊泡细胞器）的调节 细胞物质），以及炎症和先天免疫的激活，作为 LO-ND 风险基因。然而，迄今为止，它 目前尚不清楚这两个过程如何在衰老的大脑中相互作用以促进 LO-ND 的发展。我们的 数据表明，在正常衰老过程中，溶酶体可能会逐渐衰竭——即使没有特定的 疾病过程或基因 - 并进一步表明先天免疫酶 NADPH 的低级诱导 IL-6 产生的氧化酶 (Nox) 可能会导致衰老大脑中的溶酶体衰竭。令人兴奋的新数据如下， 表明衰老大脑中的溶酶体衰竭可以通过抑制 Nox 来挽救。因此根据近期 文献以及我们发表的和新的观察结果，我们认为与年龄相关的溶酶体衰竭是由于 IL-6 介导的 NADPH 氧化酶激活，并提出机制研究来测试每个组件 这个假设。该应用背后的前提是，衰老大脑中的炎症会导致进行性 溶酶体的失败得到了现有文献、我们发表的研究和新的初步数据的支持，但 没有被系统地研究过。目标 1 将检验衰老过程中溶酶体失效的假设 Nox 的炎症激活，以及 Nox 诱导由 Il-6 和 STAT3 介导的推论 发信号。我们的数据表明，Nox 抑制剂可以挽救衰老动物的溶酶体功能 这个假设的第一步，据我们所知，是第一个证明 Nox 抑制可以改善大脑的步骤 溶酶体功能。独特的小鼠模型，包括 PV-tdTomato、IL-6-/- 和诱导型神经元 Stat3-/- 小鼠 将使用高分辨率共聚焦显微镜。目标 2 将机械地决定如何 炎症会导致溶酶体衰竭并导致衰老大脑中的物质降解受损。诱发 多能干细胞 (iPSC) 衍生的人类神经元 (iPSC-huNs) 和接受 Nox 修饰处理的老年小鼠 试剂将确定损害溶酶体功能的机制。目标 3 检验挤出的假设 溶酶体货物含有活性蛋白酶，然后会损害包括神经元在内的附近细胞，并且 挤出的溶酶体物质（货物）具有促炎性。组织蛋白酶活性、神经元损伤和 将使用小胶质细胞和星形胶质细胞激活的标记物。影响：与年龄相关的神经疾病 系统是一个日益严重的医疗保健问题，但尚未出现针对这些问题的疾病缓解疗法 疾病。该提议将增进我们对炎症如何损害溶酶体能力的理解 清除并回收受损的细胞物质，为神经退行性疾病提供新的治疗靶点。