Inflammatory Mechanisms Underlie Lysosome Failure in the Aging Brain

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)，另外200万人患有帕金森氏病(PD)和其他迟发性神经退行性疾病 (LO-NDS)，到目前为止，针对这些疾病的疾病修正治疗仍然难以捉摸。而衰老则是 LO-NDS的单一最大风险因素，全基因组关联研究(GWAS)已经确定了基因 参与调节溶酶体(负责降解和回收受损的囊泡细胞器 细胞材料)，以及炎症和先天免疫的激活，如LO-ND风险基因。然而，到目前为止，它 目前尚不清楚这两个过程在衰老的大脑中如何相互作用来促进LO-NDS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--即使在缺乏特定的 疾病过程或基因--并进一步表明，先天免疫酶NADPH的低水平诱导 由IL-6引起的氧化物酶(NOX)可能会特异性地导致老化大脑中的溶酶体失效。下面是令人兴奋的新数据， 提示抑制NOx可挽救衰老脑内溶酶体功能衰竭。因此，基于最近的 文献，以及我们已发表的和新的观察结果，我们提出与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，并提出检测各组分的机理研究 这一假说。这项应用背后的前提是，老化的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 没有得到系统的研究。目标1将检验这一假设，即在衰老过程中溶酶体失败是由于 NO_x的炎症活化及其由IL-6和STAT3介导的必然结果 发信号。我们的数据显示，在衰老的动物中，NOX抑制剂可以挽救溶酶体功能 这一假设的第一步，也是我们所知的第一步，表明抑制NOx可以改善大脑 溶酶体功能。独特的小鼠模型，包括PV-tdTomato、IL-6-/-和可诱导的神经元STAT3-/-小鼠 将使用高分辨率共聚焦显微镜。目标2将从机械上决定如何 在老化的大脑中，炎症会导致溶酶体衰竭和货物降解受损。诱导式 多能干细胞(IPSC)来源的人类神经元(IPSC-HUN)和NOx修饰的老龄小鼠 试剂将确定损害溶酶体功能的机制。Aim 3测试了突出的假设 溶酶体货物含有活性的蛋白水解酶，会损害附近的细胞，包括神经元。 挤压出的溶酶体材料(货物)是促炎物质。组织蛋白酶活性、神经元损伤和神经功能损害的成像 小胶质细胞和星形胶质细胞激活的标志物将被使用。影响：与年龄相关的神经性疾病 医疗系统是一个日益严重的卫生保健问题，但目前还没有出现针对这些疾病的治疗方法 疾病。这一建议将增进我们对炎症如何损害溶酶体能力的理解 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.