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: 9923516
• 负责人: Laura L Dugan
• 金额: $ 40.51万
• 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/9923516
• 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; 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