Neutrophil Exosomes: New Pathogenic Entities in COPD

COPD是一种慢性炎症性肺部疾病，是美国第三大死亡原因。 对美国退伍军人和现役军人有重大影响。尽管 患病率和可归因的发病率/死亡率增加，没有特定的COPD治疗方法 从而改变疾病的自然发展史。我们的团队和其他人提供了大量证据 蛋白水解损伤作为COPD进展的重要组成部分。然而，在这方面， 我们对蛋白酶如何绕过肺内强大的抗蛋白酶屏障的理解能力很差 明白在这里，我们研究了一种新的致病实体，嗜中性粒细胞衍生的外泌体， 在其表面上表达蛋白酶中性粒细胞弹性蛋白酶（NE）。我们提供初步数据 证明这些外泌体具有活性NE酶活性，能够降解 肺细胞外基质（ECM）。重要的是，我们强调外泌体相关的NE是耐药的， 其天然存在的抗蛋白酶，α-1抗胰蛋白酶（A1 AT），并可导致暴发性 肺气肿。对于这项提案，我们将建立在这些开创性的 观察，首先通过检查烟雾的影响，以诱导这些蛋白水解的释放 来自PMN的外来体（特异性目标1a），然后检查外来体的抗蛋白酶抗性 从COPD和非COPD受试者中分离，重点是诱导NE与这些受试者分离。 外泌体增强内源性抗蛋白酶敏感性（特异性目标1b）。接下来，我们将使用 来自6个月吸烟小鼠模型的支气管肺泡灌洗（BAL）样品，分离PMN来源的 外泌体，并将其气管内递送到幼稚小鼠体内以诱导肺气肿，从而抑制这些外泌体 通过NE解离的作用（具体目标2）。最后，我们将研究一组COPD受试者 （当前或既往吸烟者）和非COPD受试者（吸烟者和从不吸烟者），以确定 这些组群中NE相关外泌体的表达和这些测量值随时间的稳定性 （具体目标3）。这些目标的成功实现将使人们更好地了解 PMN外泌体作为COPD的关键致病实体，随着对PMN外泌体的认识的提高， 其不受约束的蛋白酶活性的下游效应。重要的是，这些研究可能会导致 开发一种新的生物标志物和潜在的新治疗方法，用于治疗 被诊断为COPD的退伍军人。

COPD is a chronic inflammatory pulmonary condition which the 3rd leading cause of death in the United States and has significant impact on the US Veteran and active military population. Despite its prevalence and increased attributable morbidity/mortality, there are no specific COPD therapeutics which alter the natural history of the disorder. Our group and others have provided extensive evidence of the importance of proteolytic damage as a critical component to the progression of COPD. However, our ability to understand how proteases bypass the robust antiprotease shield within the lung is poorly understood. Here, we examine a new pathogenic entity, the neutrophil-derived exosome, which expresses the protease neutrophil elastase (NE) on its surface. We provide preliminary data demonstrating these exosomes have active NE enzymatic activity, capable of degrading components of the lung extracellular matrix (ECM). Importantly, we highlight that exosome-associated NE is resistant to its naturally occurring antiprotease, alpha-1 antitrypsin (A1AT), and can lead to fulminant emphysema when intratracheally administered in vivo. For this proposal, we will build on these seminal observations, first by examining the impact of smoke to induce the release of these proteolytic exosomes from PMNs (Specific Aim 1a) and then examining the antiprotease resistance of exosomes isolated from COPD and non-COPD subjects, with a focus of inducing NE disassociation from these exosomes to enhance endogenous antiprotease sensitivity (Specific Aim 1b). Next, we will use bronchoalveolar lavage (BAL) samples from 6-month smoking mouse model, isolate PMN-derived exosomes, and intratracheally deliver these into naïve mice to induce emphysema, inhibiting these effects via NE disassociation (Specific Aim 2). Finally, we will examine a cohort of COPD subjects (current or former smokers) and non-COPD subjects (smokers and never smokers) to determine the expression of NE-associated exosomes in these cohorts and stability of these measurements over time (Specific Aim 3). The successful completion of these aims will lead to an increased understanding of the PMN exosome as a critical pathogenic entity in COPD, with improved understanding of the downstream effects of its unfettered protease activity. Importantly, these studies will likely result in the development of a new biomarker and potential new therapeutic approaches for the treatment of Veterans who are diagnosed with COPD.