Urokinase, Defensin and Acute Lung Injury

尿激酶、防御素和急性肺损伤

• 批准号: 7029470
• 负责人: Douglas Brock Cines
• 金额: $ 40.19万
• 依托单位: UNIVERSITY OF TEXAS HLTH CTR AT TYLER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7029470
• 关键词: CHO cells; acute disease /disorder; biological signal transduction; defensins; enzyme activity; enzyme linked immunosorbent assay; genetically modified animals; immunoprecipitation; integrins; laboratory mouse; lung disorder; muscle contraction; oxygen tension; phosphorylation; plasminogen activator; protein binding; protein protein interaction; radiotracer; urokinase; vascular endothelium permeability; vascular smooth muscle; western blottings

Acute lung injury (ALI) is characterized by an exudative phase of alveolar-capillary leak and leukocyte extravasation followed by pulmonary vasoconstruction and intrapulmonary shunting in response to hypoxia. Although alterations in vasoreactivity contribute to the morbidity of ALI, the signal-transducing mechanism underlying the sequential changes in vascular permeability is incompletely defined. Our studies suggest that urokinase plasminogen activator (uPA) and a-defensins secreted by activated neutrophils exert opposing effects on vascular tone through low-density lipoprotein-related receptor (LRP) and the integrin alpha-v-beta3, and that system is regulated by oxygen tension. Based on these findings, we will explore the hypothesis that uPA regulates vascular contractility and influences downstream permeability by forming a signal-transducing complex with LRP and alpha-v-beta3 that is dysregulated by hypoxia and disrupted by a-defensin. In Specific Aim 1 we will study the molecular determinants required to form ternary complexes between uPA, Ovfo and LRP, its role in pulmonary vascular contraction, and the effect of defensin. In Specific expression and signal transduction will be elucidated. In Specific Aim 3 the role of LRP/alpha-v-beta3 in the development of ALI will be examined in wildtype, uPA -/- and defensin-transgenic mice. Proteolytic and the non-proteolytic effects of uPA on the vasculature will be distinguished through a novel uPA and d-kringle uPA transgenic mouse delivery system using platelet-specific promoters. Taken together these studies will provide insight into the regulation of vascular tone and permeability by uPA in ALI and identify novel agonists (uPA and defensin) and a novel signal-transducing pathway (LRP/ alpha-v-beta3) as potential sites to ameliorate disease severity.

急性肺损伤（ALI）的特征是肺泡毛细血管泄漏和白细胞渗出的渗出阶段，然后是肺血管结构和肺内分流，响应缺氧。尽管血管反应性的改变有助于ALI的发病率，但未完全定义了血管通透性的顺序变化的信号传递机制。我们的研究表明，激活的中性粒细胞分泌的尿激酶纤溶酶原激活剂（UPA）和A-防御素通过低密度脂蛋白相关受体（LRP）和整联蛋白α-V-Beta对血管张力产生相反的影响，并且该系统受氧气张力调节。基于这些发现，我们将探讨以下假设：UPA通过与LRP和Alpha-V-Beta3形成信号传递复合物来调节血管收缩性并影响下游渗透率，而LRP和Alpha-V-Beta3被缺氧失调并被A-脱蛋白扰动。在特定目标1中，我们将研究分子决定因素 需要在UPA，OVFO和LRP之间形成三元复合物，该复合物在肺血管中的作用 收缩和防御素的作用。在特定的表达和信号转导中将被阐明。在特定的目标3中，LRP/Alpha-V-Beta3在ALI开发中的作用将在WildType，UPA - / - 和Defensin-Transgenic小鼠中进行检查。 UPA对脉管系统的蛋白水解和非蛋白水解作用将通过使用血小板特异性启动子进行新颖的UPA和D-Kringle UPA转基因小鼠递送系统来区分。结合这些 研究将洞悉UPA在ALI中调节血管张力和渗透性，并鉴定新型激动剂（UPA和防御素）以及一种新型的信号转移途径（LRP/ Alpha-V-Beta3）作为减轻疾病严重程度的潜在部位。