A Novel Exosomal Inflammatory Pathway

项目摘要 该计划定义了一些人所谓的嗜中性炎症的范式转移途径 与IL-8相关的“经典”模式不同，其在慢性炎症中可以自我繁殖。 疾病如COPD。具体地，IL-8启动中性粒细胞（PMN）内流，PMN反过来释放基质 金属蛋白酶（MMPs）和脯氨酰内肽酶（PE），其降解胶原并产生PMN特异性的 matrikine，脯氨酸-甘氨酸-脯氨酸（PGP）。在更常见的急性炎症情况下， 被破坏PGP的白三烯A4水解酶（LTA 4 H）的氨肽酶活性终止。香烟 吸烟（CS）可以化学修饰和抑制LTA 4 H的氨肽酶活性，但不能改变水解酶活性 乙酰化PGP使其对LTA 4 H免疫。这导致PGP水平持续升高， COPD中的嗜酸性炎症。在本计划了解PGP系统的过程中， COPD、CF和ARDS的一种新的潜在预后生物标志物，将基质降解与血管渗漏联系起来， 并发现了一种促炎酶LTA 4 H的抗炎作用。PGP最近也被 显示细胞外基质降解与急性肺损伤、炎症性肠病、缺血性脑损伤 中风和急性肺部感染的调节。因此，PGP系统的发现 特别重要的是作为一个基本的调解人的病理生理学在一些疾病和器官。一 我们的研究的一个神秘的方面是无法在体外用胶原蛋白和适当的药物产生PGP。 蛋白酶溶液这个R35应用程序的论点是，这个谜是由于PGP的要求， 产生酶，如PE，是外泌体相关的。这一观点得到了许多观察的支持，大多数 值得注意的是，来自COPD患者而非对照的气道外泌体是PMN衍生的，并引起COPD样的 当转移到小鼠时的表型。总的来说，这些发现导致我们的假设， 构成炎症过程的一个新方面，并可能参与慢性炎症性疾病， 通过PGP途径治疗COPD。如果成功，该项目的结果将定义一个新的实体，即蛋白水解酶。 外泌体，其通过PGP生成驱动嗜酸性炎症，PGP生成受LTA 4 H调节， 导致小鼠患上类似COPD的疾病。在人类研究中，我们将对蛋白水解外泌体进行表型分析， 它们是否是COPD的生物标志物，与疾病参数相关，并且可以将病理学从 人类到老鼠在COPD的吸烟小鼠模型中，我们将表征这种外泌体的进化， 它们是否能将疾病从烟熏动物身上传染给未感染的动物。虽然，新致病性的定义 实体是令人生畏的，该计划的跟踪记录和PI和团队的专业知识表明， 奋进。如果是这样的话，对蛋白水解外泌体的完全理解可能会导致新的诊断方法， 用于慢性炎性疾病如COPD的治疗剂。

PROJECT SUMMARY This Program has defined what some have called a paradigm shifting pathway of neutrophilic inflammation which, unlike the “classic” mode associated with IL-8, can become self-propagating in chronic inflammatory diseases such as COPD. Specifically, IL-8 initiates neutrophil (PMN) influx, the PMNs in turn release matrix metalloproteases (MMPs) and prolyl endopeptidase (PE) which degrade collagen and generate the PMN-specific matrikine, proline-glycine-proline (PGP). In more common acute inflammatory circumstances, the PGP pathway is terminated by the aminopeptidase activity of leukotriene A4 hydrolase (LTA4H) which destroys PGP. Cigarette smoking (CS) can chemically modify and inactivate LTA4H’s aminopeptidase but not hydrolase activity as well as acetylate PGP rendering it immune to LTA4H. This drives persistently elevated PGP levels and chronic neutrophilic inflammation in COPD. In the Program’s journey to understand the PGP system, we have identified a novel potential prognostic biomarker for COPD, CF, and ARDS, linked matrix degradation to vascular leak, and discovered an anti-inflammatory role for a pro-inflammatory enzyme, LTA4H. PGP has also recently been shown to link extracellular matrix degradation to: acute lung injury, inflammatory bowel disease, ischemic brain stroke, and modulation of acute pulmonary infection. Consequently, the discovery of the PGP system has particular significance as a fundamental mediator of pathophysiology in a number of disorders and organs. One enigmatic aspect of our studies has been an inability to generate PGP in vitro with collagen and the appropriate proteases in solution. The thesis of this R35 application is that this enigma is due to the requirement that PGP generating enzymes, such as PE, be exosome associated. This idea is supported by many observations, most notably, that airway exosomes from COPD patients, but not controls, are PMN-derived and cause a COPD-like phenotype when transferred to mice. Collectively, the findings led to our hypothesis that proteolytic exosomes constitute a new aspect of the inflammatory process and may participate in chronic inflammatory disorders such as COPD via the PGP pathway. If successful, the results of this project will define a novel entity, i.e. proteolytic exosome, which drives neutrophilic inflammation via PGP generation which is regulated by LTA4H and can cause a COPD-like disease in mice. In human studies, we will phenotype proteolytic exosomes and delineate whether they are biomarkers of COPD that correlate with disease parameters and can transfer pathology from humans to mice. In a smoking mouse model of COPD we will characterize the evolution of such exosomes and whether they can transfer disease from smoked to naïve animals. Although, the definition of a new pathogenic entity is daunting, the track record of this Program and the expertise of the PI and team suggest a successful endeavor. If so, a complete understanding of the proteolytic exosome may lead to new diagnostics and therapeutics for chronic inflammatory diseases such as COPD.