Mechanisms of Prostacyclin-Mediated Lung Endothelial Barrier Protection

前列环素介导的肺内皮屏障保护机制

• 批准号: 8371434
• 负责人: Konstantin Birukov
• 金额: $ 39.5万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8371434
• 关键词: Acceleration; Actins; Acute; Acute Lung Injury; Address; Adhesions; Adhesives; Adult Respiratory Distress Syndrome; Affect; Aftercare; Air; Animal Model; Automobile Driving; Bacteria; Blood Vessels; Blood gas; CCM1 gene; Cell Adhesion; Cell Adhesion Molecules; Cell Culture Techniques; Cell physiology; Cell-Matrix Junction; Cells; Complex; Cyclic AMP; Cytoskeleton; Development; Down-Regulation; Drug Design; Endothelial Cells; Experimental Models; FDA approved; Functional disorder; Future; Genetic Models; Guanosine Triphosphate Phosphohydrolases; Heating; IL8 gene; Iloprost; In Vitro; Inflammation; Inflammatory; Injury; Intercellular Junctions; Intercellular adhesion molecule 1; Intervention; Knowledge; Liquid substance; Lung; Lung Inflammation; Mediating; Modeling; Molecular; Molecular Target; Morbidity - disease rate; Mus; Neutrophil Infiltration; Pathway interactions; Peripheral; Permeability; Pharmaceutical Preparations; Pharmacotherapy; Phase; Phenotype; Play; Pre-Clinical Model; Prevention; Preventive; Process; Production; Prostaglandins I; Protective Agents; Proteins; Pulmonary Edema; Recovery; Regulation; Resolution; Respiratory physiology; Role; Scheme; Signal Transduction; Staphylococcus aureus; Structure; Testing; Time; Vascular Endothelial Cell; Vascular Permeabilities; Ventilator-induced lung injury; analog; attenuation; clinically relevant; cytokine; drug testing; effective therapy; gain of function; in vivo; loss of function; lung injury; monolayer; mortality; neutrophil; novel; protective effect; repaired; research study; restoration; rho; rho GTP-Binding Proteins; septic; vascular endothelial dysfunction; vascular inflammation

DESCRIPTION (provided by applicant): Development of effective therapies for treatment of acute lung injury (ALI) and adult respiratory distress syndrome (ARDS) remains a challenging task. Many experimental models for testing of novel protective agents utilize preventive or concurrent treatment during ALI induction, while post-treatment represents more clinically relevant intervention. Such differences in the timing of drug administration may have dramatic impact on the efficiency of treatment and activation of specific molecular mechanisms directing resolution of ongoing injury in contrast to blocking onset of ALI by drug pretreatment. This proposal will fill this void and explore effects of post-treatment with FDA-approved prostacyclin (PC) analog iloprost in the in vitro and in vivo septic ALI models. Inflammation and increased endothelial cell (EC) permeability play a major role in the pathophysiology of ALI. During the previous cycle of this proposal, we characterized for the first time the molecular mechanisms of PC-mediated protection in aseptic model of ventilator induced lung injury. Our preliminary studies suggest potent protective effects of PC pretreatment against LPS-induced lung inflammation and vascular leak. This proposal will investigate effects of PC post-treatment in cell culture and animal models of septic ALI caused by Gram-positive heat-inactivated Staphylococcus Aureus bacteria (HKSA). We hypothesize that signaling by Rap1 GTPase plays a dual role in PC-induced acceleration of ALI resolution via promotion of EC barrier repair and suppression of inflammatory endothelial activation. Aim-1 will evaluate effects of PC post-treatment and define a role of Rap1 in acceleration of barrier recovery in HKSA challenged EC. Aim-2 will define molecular mechanisms downstream of Rap1 involved in EC barrier recovery. We will study a role of Rap1 effectors KRIT1 and RIAM in enhancement of EC adhesive structures and peripheral cytoskeleton essential for re-establishment of EC barrier. Aim-3 will study a role of Rap1, KRIT1 and RIAM stimulation by PC post-treatment in downregulation of HKSA-induced pulmonary EC activation. Aim-4 will elucidate specific role of Rap1, KRIT1 and Riam in PC-facilitated ALI recovery in vivo using "loss of function" and "gain of function" molecular approaches and mouse genetic models. These studies will characterize novel protective mechanisms and identify new protein targets for future therapies aimed at prevention of the pulmonary vascular barrier dysfunction associated with acute lung injury. PUBLIC HEALTH RELEVANCE: Adult respiratory distress syndrome (ARDS) remains a major cause of morbidity and mortality with an overall mortality rate of 30-40%. The acute phase of lung injury is characterized by increased endothelial permeability and compromise of the blood-gas barrier, which allows an influx of protein-rich fluid into the air spaces, causing pulmonary edema. Development of effective therapies for ALI/ARDS treatment currently represents major a challenge. This study will investigate molecular mechanisms underlying protective effects of prostacyclin against pulmonary vascular endothelial dysfunction and characterize for the first time novel mechanisms of recovery in the model of Gram-positive septic ALI. These studies will expand our knowledge about molecular mechanisms leading to ALI resolution and may identify new targets for drug therapies.

描述(由申请人提供)：开发治疗急性肺损伤(ALI)和成人呼吸窘迫综合征(ARDS)的有效疗法仍然是一项具有挑战性的任务。许多用于测试新型保护剂的实验模型在ALI诱导期间采用预防性或同时治疗，而后期治疗代表更多临床相关的干预措施。这种给药时机的差异可能会对治疗的效率和特定分子机制的激活产生巨大影响，这些分子机制指导着持续损伤的解决，而不是通过药物预处理来阻止ALI的发生。这项建议将填补这一空白，并探索FDA批准的前列环素(PC)类似物iloprost在体外和体内感染性ALI模型中的后处理效果。炎症反应和内皮细胞(EC)通透性增加在ALI的病理生理过程中起重要作用。在这项提案的前一个周期中，我们首次描述了无菌呼吸机诱导的肺损伤模型中PC介导的保护的分子机制。我们的初步研究表明，PC预处理对内毒素诱导的肺部炎症和血管渗漏具有有效的保护作用。这项建议将研究PC后处理在细胞培养和由革兰氏阳性热灭活金黄色葡萄球菌(HKSA)引起的败血症ALI动物模型中的作用。我们推测，RAP1 GTP酶信号在PC诱导的ALI分解中起双重作用，即通过促进EC屏障修复和抑制炎性内皮细胞激活来加速ALI的分解。AIM-1将评估PC后处理的效果，并确定RAP1在HKSA挑战EC中加速屏障恢复的作用。AIM-2将定义RAP1下游参与EC屏障恢复的分子机制。我们将研究RAP1效应器KRIT1和RIAM在增强EC黏附结构和外周细胞骨架方面的作用，这是重建EC屏障所必需的。AIM-3将研究PC后处理对RAP1、KRIT1和RIAM刺激在下调HKSA诱导的肺内皮细胞激活中的作用。AIM-4将利用“功能丧失”和“功能获得”分子方法和小鼠遗传模型，阐明Rap1、KRIT1和Riam在PC促进的ALI体内恢复中的特定作用。这些研究将表征新的保护机制，并为未来旨在预防与急性肺损伤相关的肺血管屏障功能障碍的治疗确定新的蛋白质靶点。 公共卫生相关性：成人呼吸窘迫综合征(ARDS)仍然是发病率和死亡率的主要原因，总死亡率为30%-40%。肺损伤的急性期以内皮通透性增加和血气屏障受损为特征，这允许富含蛋白质的液体进入空气空间，导致肺水肿。开发治疗ALI/ARDS的有效疗法目前是一个重大挑战。本研究将探讨前列环素对肺血管内皮细胞功能障碍的保护作用的分子机制，并首次在革兰氏阳性败血症ALI模型中描述新的恢复机制。这些研究将扩大我们对导致ALI解决的分子机制的了解，并可能确定药物治疗的新靶点。