Inflammatory Mechanisms Underlie Lysosome Failure in the Aging Brain

根据疾病控制中心（CDC）的数据，有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 尽管这些疾病是LO-ND，但迄今为止，用于这些疾病的疾病修饰治疗仍然难以捉摸。虽然衰老是 作为LO-ND的最大风险因素，全基因组关联研究（GWAS）已经确定了 参与调节溶酶体（负责降解和回收受损的泡状细胞器 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 数据表明，在正常衰老过程中，溶酶体可能会逐渐衰竭，即使在缺乏特定的 疾病过程或基因-并进一步表明，低级别诱导的先天免疫酶，NADPH IL-6诱导的Nox可能特异性地导致衰老大脑中的溶酶体衰竭。令人兴奋的新数据，下面， 显示老化脑中的溶酶体衰竭可以通过抑制Nox来挽救。根据最近 结合文献，以及我们发表的和新的观察，我们提出年龄相关的溶酶体衰竭是由于 IL-6介导的NADPH氧化酶的激活，并提出机制研究，以测试每个组件 这一假设。这个应用背后的前提是，老化大脑中的炎症会导致渐进性的 现有文献、我们已发表的研究和新的初步数据都支持溶酶体的失败，但 没有被系统地研究过。目的1将检验老化过程中溶酶体失效是由于 Nox的炎性激活，以及Nox诱导由IL-6和STAT 3介导的推论 信号我们的数据显示，在衰老动物中，溶酶体功能可以通过Nox抑制剂来拯救，这支持了 这是这一假设的第一步，据我们所知，这是第一个表明Nox抑制可以改善大脑 溶酶体功能独特的小鼠模型，包括PV-tdTomato、IL-6-/-和可诱导神经元Stat 3-/-小鼠 将使用高分辨率共焦显微镜。目标2将机械地确定如何 炎症在老化的大脑中产生溶酶体失效和受损的货物降解。诱导 多能干细胞（iPSC）衍生的人神经元（iPSC-huN）和用Nox修饰的人神经元处理的老年小鼠。 试剂将确定损害溶酶体功能的机制。目标3测试突出的假设 溶酶体货物含有活性蛋白酶，其然后损伤附近的细胞，包括神经元，并且 挤出的溶酶体物质（货物）是促炎性的。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活化的标记物。影响：与神经系统相关的疾病 系统是一个不断增长的卫生保健问题，但还没有出现针对这些系统的疾病改善治疗方法 疾病这一提议将促进我们对炎症如何损害溶酶体的能力的理解， 清除和回收受损的细胞物质，为神经退行性疾病提供新的治疗靶点。

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.