A New Pathway for Neutrophil-induced Airway Inflammation

描述（由申请方提供）：在某些情况下，多形白细胞（PMN）募集至气道炎症部位可通过产生蛋白酶、活性氧、促炎细胞因子和趋化因子导致组织损伤。PMN被认为在急性肺疾病以及慢性阻塞性肺疾病中起作用，并且在囊性纤维化中促成炎症和肺损伤。我们在此描述了一种新的途径，中性粒细胞流入和损害的气道，可能代表一个新的治疗目标，某些肺部疾病。特别是，当胶原蛋白被化学或酶促降解时，产生三肽PGP，其在体外对PMN具有趋化性。在体内，气道暴露于PGP elevened一个显着的流入的中性粒细胞，但不是单核细胞。气道长期暴露于PGP会导致肺泡扩大和右心室肥大。使用电喷雾电离-液相色谱-质谱（ESI-LC-MS/MS），在暴露于内毒素（LPS）的动物的气道中检测到PGP。此外，该肽实质上有助于PMN流入发炎的气道。PGP的趋化活性显然是由于与CXC趋化因子的受体结合基序的非凡结构相关性，如含有该序列或类似物的IL-8。我们已经设计了一种新的肽序列精氨酸-苏氨酸-精氨酸（RTR）结合PGP和有效地阻止肽的体外趋化活性和体内病理生理效应。RTR还抑制CXC趋化因子活性，这显然是由于PGP和趋化因子之间的共享结构。因此，RTR代表了一种潜在的治疗剂，可以阻断炎症的趋化因子和PGP途径。这些结果导致了该应用的以下目标。1.确定PGP是否结合CXC趋化因子受体（R）并激活CXCR偶联效应通路。2.评估气道炎症过程中产生的含PGP肽的谱，以及PGP是否在急性炎症过程中招募PMN到气道。3.确定PMN是否是PGP介导的肺泡扩大和右心室肥大所必需的。4.评价PGP与CXC趋化因子在持续性LPS介导的肺部疾病模型中的相对病理生理作用。5.在LPS介导的肺部疾病模型中测试RTR作为PGP和CXC趋化因子途径的拮抗剂。

DESCRIPTION (provided by applicant): Under certain circumstances, polymorphonuclear leukocyte (PMN) recruitment to sites of airway inflammation can lead to tissue damage via the production of proteases, reactive oxygen species, proinflammatory cytokines and chemokines. PMN are thought to play a role in acute lung diseases as well as chronic obstructive pulmonary diseases and contribute to inflammation and lung damage in cystic fibrosis. We herein describe a novel pathway of PMN influx and damage to the airways that may represent a new therapeutic target for certain pulmonary diseases. In particular, when collagen is chemically or enzymatically degraded a tripeptide, PGP, is generated that is chemotactic for PMN in vitro. In vivo, airway exposure to PGP elicits a marked influx of PMN, but not monocytes. More chronic airway exposure to PGP causes alveolar enlargement and right ventricular hypertrophy. Using electrospray ionization-liquid chromatography- mass spectrometry (ESI-LC-MS/MS), PGP is detected in the airways of animals exposed to endotoxin (LPS). In addition, the peptide substantially contributes to PMN influx into inflamed airways. The chemotactic activity of PGP apparently results from an extraordinary structural relatedness to a receptor binding motif of CXC chemokines, like IL-8 that contain this sequence or a close analog. We have designed a novel peptide with the sequence arginine-threonine-arginine (RTR) that binds PGP and potently blocks the peptide's in vitro chemotactic activity and in vivo pathophysiologic effects. RTR also inhibits CXC chemokine activity apparently as a result of the shared structure between PGP and the chemokines. Thus, RTR represents a potential therapeutic agent that can block both the chemokine and PGP pathways of inflammation. These results have led to the following goals for this application. 1. Determine whether PGP binds CXC chemokine receptors (R) and activates CXCR coupled effector pathways. 2. Evaluate the spectrum of PGP-containing peptides that are produced during airway inflammation and whether PGP recruits PMN to the airways during acute inflammation. 3. Determine whether PMN are necessary for PGP-mediated alveolar enlargement and right ventricular hypertrophy. 4. Evaluate the relative pathophysiologic roles of PGP as compared to CXC chemokines in a model of persistent LPS-mediated pulmonary disease. 5. Test RTR as an antagonist of the PGP and CXC chemokine pathways in the LPS-mediated pulmonary disease model.