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步治疗，而治疗后则代表更具临床相关性的干预。与通过药物预处理阻断 ALI 的发作相比，药物给药时间的这种差异可能会对治疗效率和指导解决持续损伤的特定分子机制的激活产生巨大影响。该提案将填补这一空白，并探索 FDA 批准的前列环素 (PC) 类似物伊洛前列素在体外和体内脓毒症 ALI 模型中后治疗的效果。炎症和内皮细胞 (EC) 通透性增加在 ALI 的病理生理学中发挥着重要作用。在该提案的前一个周期中，我们首次描述了呼吸机引起的肺损伤无菌模型中 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 LPS 诱导的肺部炎症和血管渗漏具有有效的保护作用。该提案将研究 PC 后处理对由革兰氏阳性热灭活金黄色葡萄球菌 (HKSA) 引起的脓毒症 ALI 的细胞培养和动物模型的影响。我们假设 Rap1 GTPase 信号传导通过促进 EC 屏障修复和抑制炎症内皮激活，在 PC 诱导的 ALI 加速缓解中发挥双重作用。 Aim-1 将评估 PC 后处理的效果，并确定 Rap1 在加速 HKSA 挑战的 EC 屏障恢复中的作用。 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 效应子 KRIT1 和 RIAM 在增强 EC 粘附结构和外周细胞骨架中的作用，这对于重建 EC 屏障至关重要。 Aim-3 将研究 PC 后处理刺激 Rap1、KRIT1 和 RIAM 在下调 HKSA 诱导的肺 EC 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 体内恢复中的具体作用。这些研究将表征新的保护机制，并确定未来治疗的新蛋白质靶点，旨在预防与急性肺损伤相关的肺血管屏障功能障碍。 公共卫生相关性：成人呼吸窘迫综合征 (ARDS) 仍然是发病和死亡的主要原因，总死亡率为 30-40%。肺损伤急性期的特点是内皮通透性增加和血气屏障受损，导致富含蛋白质的液体流入空气空间，引起肺水肿。目前，开发治疗 ALI/ARDS 的有效疗法是一项重大挑战。本研究将探讨前列环素对肺血管内皮功能障碍的保护作用的分子机制，并首次表征革兰氏阳性脓毒症 ALI 模型中的新恢复机制。这些研究将扩展我们对导致 ALI 缓解的分子机制的了解，并可能确定药物治疗的新靶点。