Endothelial thrombospondin-1 in matrix proteolysis during Pseudomonal lung injury

项目概要/摘要： 急性呼吸窘迫综合征（ARDS）是一种以快速进行性呼吸道感染为特征的综合征， 衰竭和难治性低氧血症，并且是全世界危重患者发病和死亡的主要原因。 ARDS最常见的危险因素是严重的细菌性肺炎， 经常受到医院感染的困扰，包括下呼吸道感染（LRTI）。假单 铜绿假单胞菌（PA）是ICU常见的病原体，PA肺炎与ICU患者死亡率增加相关。 与其他革兰氏阴性病原体相比，呼吸机相关性肺炎。PA已被证明会导致 广泛的蛋白水解损伤导致动物组织损伤和肺泡-毛细血管屏障的降解 模型，部分通过分泌的外切蛋白酶如LasB。金属蛋白酶LasB也已被证明 降解在屏障完整性中重要的连接蛋白。虽然病原体衍生的毒力因子已被 广泛的特点，有有限的知识，关于主机机制，防止 肺中的蛋白水解损伤和血管渗透性。血小板反应蛋白-1（TSP-1）是一种基质糖蛋白， 包括炎症调节在内的多种功能。TSP-1以前已被证明可以抑制宿主- 来源的丝氨酸蛋白酶和病原体来源的外切蛋白酶LasB。肺内皮细胞表达TSP-1， 细胞，但其在病原体诱导的损伤中的作用是未知的。本提案的主要目的是确定 内皮细胞TSP-1对PA诱导的基质蛋白水解和屏障功能障碍的保护作用 肺损伤目的1将确定TSP-1是否对细胞间连接复合物的破坏具有保护作用 和体外屏障功能。目的2将确定内皮TSP-1是否促进体内血管完整性。通过 提高我们对病原体引发肺损伤过程中宿主保护机制的理解，该项目 可能为ARDS患者的潜在治疗靶点提供理论依据。拟议的培训计划将 促进先进的实验室技能的发展，包括细胞和组织成像，小鼠遗传学和体内 感染性肺损伤模型。此外，该项目为申请人提供了机会， 在专门赞助商的密切指导和参与下，发展作为医生科学家的专业知识， 匹兹堡大学强大的研究环境。

Project Summary/Abstract: Acute Respiratory Distress Syndrome (ARDS) is a syndrome characterized by rapidly progressive respiratory failure and refractory hypoxemia and is a major cause of morbidity and mortality in critically ill patients worldwide. The most common risk factor for ARDS is severe bacterial pneumonia and patients with ARDS are also frequently plagued by nosocomial infections including lower respiratory tract infections (LRTIs). Pseudomonas aeruginosa (PA) is a common ICU pathogen and PA pneumonia is associated with increased mortality in ventilator associated pneumonia compared to other gram-negative pathogens. PA has been shown to cause extensive proteolytic injury leading to tissue damage and degradation of the alveolar-capillary barrier in animal models, in part through secreted exoproteases such as LasB. The metalloprotease LasB has also been shown to degrade junctional proteins important in barrier integrity. While pathogen derived virulence factors have been extensively characterized, there is limited knowledge regarding the host mechanisms that protect against proteolytic injury and vascular permeability in the lungs. Thrombospondin-1 (TSP-1) is a matrix glycoprotein with a variety of functions including regulation of inflammation. TSP-1 has been previously shown to inhibit host- derived serine proteases and the pathogen-derived exoprotease, LasB. TSP-1 is expressed by lung endothelial cells but its role in pathogen-induced injury is unknown. The main objective of this proposal is to determine the role of endothelial TSP-1 in protection against matrix proteolysis and barrier dysfunction following PA induced lung injury. Aim 1 will determine if TSP-1 is protective against the disruption of intercellular junctional complexes and barrier function in vitro. Aim 2 will determine if endothelial TSP-1 promotes vascular integrity in vivo. By improving our understanding of host protective mechanisms during pathogen triggered lung injury, this project may provide rationale for potential therapeutic targets in patients with ARDS. The proposed training plan will promote development of advanced laboratory skills including cell and tissue imaging, mouse genetics and in vivo models of infection-induced lung injury. Moreover, this project with provide the applicant with the opportunity to develop expertise as a physician-scientist under the close mentoring and involvement of dedicated sponsors in a robust research environment at the University of Pittsburgh.