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渗漏和白细胞渗出，随后是肺血管构筑和肺内分流，以应对缺氧。尽管血管反应性改变导致ALI的发病，但血管通透性连续变化背后的信号转导机制尚不完全清楚。我们的研究表明，激活的中性粒细胞分泌的尿激酶型纤溶酶原激活物(UPA)和α-防御素通过低密度脂蛋白相关受体(LRP)和整合素α-v-β3对血管张力产生相反的作用，该系统受氧分压的调节。基于这些发现，我们将探索uPA通过与LRP和α-v-beta3形成信号转导复合体来调节血管收缩和影响下游通透性的假设，该复合体受低氧调节，并被α-防御素破坏。在具体目标1中，我们将研究分子决定因素。 UPA、Ovfo和LRP形成三元复合体的必要性及其在肺血管中的作用 收缩，以及防御素的作用。在具体的表达和信号转导方面将被阐明。在具体目标3中，将在野生型、uPA-/-和防御素转基因小鼠中检测LRP/α-v-beta3在ALI发生发展中的作用。通过一种新型的uPA和d-kringle uPA转基因小鼠递送系统，利用血小板特异性启动子，将区分uPA对血管系统的蛋白分解和非蛋白分解作用。把这些放在一起 研究将深入了解uPA对ALI血管张力和通透性的调节，并确定新的激动剂(uPA和防御素)和新的信号转导途径(LRP/α-v-beta3)是缓解疾病严重程度的潜在部位。