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，有500万美国人生活在阿尔茨海默氏病 （AD），另外200万帕金森氏病（PD）和其他晚发神经退行性疾病 （LO-NDS），但迄今为止，这些疾病的疾病改良治疗仍然难以捉摸。而衰老是 LO-ND的最大危险因素，基因组广泛的关联研究（GWAS）已经鉴定了基因 参与调节溶酶体（囊泡细胞器，导致降解和回收损坏 细胞材料），以及炎症和先天免疫的激活，作为LO-ND风险基因。但是，到目前为止 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，即使在没有特定的情况下，溶酶体也可能在正常衰老时逐渐失败 疾病过程或基因 - 进一步表明先天免疫酶的低度诱导NADPH IL-6的氧化酶（NOX）可能会特别导致大脑衰老的溶酶体衰竭。令人兴奋的新数据，下面 表明衰老大脑中的溶酶体衰竭可以通过抑制NOx做出反应。因此基于最近的 文学以及我们已发表的新观察，我们建议与年龄有关的溶酶体失败到期 为IL-6介导的NADPH氧化物的激活，并提出机械研究以测试每个成分 这个假设。该应用程序背后的前提，衰老大脑的炎症会导致进步 溶酶体的失败得到了现有文献，我们已发表的研究和新的初步数据的支持，但已有 没有系统地研究。 AIM 1将检验以下假设：衰老过程中的溶酶体衰竭是由于 NOX的炎症激活，以及NOX诱导是由IL-6和STAT3介导的推论 信号。我们的数据表明，NOX抑制剂可以在衰老的动物支持中挽救溶酶体功能 据我们所知，该假设的第一步是第一个表明NOX抑制可以改善大脑的 溶酶体功能。独特的鼠标模型，包括PV-TDTOMATO，IL-6 - / - 和诱导的神经元STAT3 - / - 小鼠 将使用高分辨率共聚焦显微镜。 AIM 2将从机械上确定如何 炎症会产生溶酶体衰竭并在衰老大脑中的货物降解受损。诱导 多能干细胞（IPSC）衍生的人神经元（IPSC-huns），并用NOX修饰治疗的老年小鼠 代理将确定损害溶酶体功能的机制。 AIM 3测试了挤出的假设 溶酶体货物中含有活性蛋白酶，然后损坏附近包括神经元的细胞，并且 挤出的溶酶体材料（货物）是促炎性的。组织蛋白酶活性，神经元损伤和 将采用小胶质细胞和星形胶质细胞激活的标记。影响：神经与年龄有关的疾病 系统是一个不断增加的医疗保健问题，但没有针对这些疾病的治疗方法 疾病。该建议将促进我们对炎症如何损害溶酶体的能力的理解 清除和回收损坏的细胞材料为神经退行性疾病提供新的治疗靶标。