Regulation of Lung Epithelial Fibrinolysis by Urokinase

描述（由申请方提供）：纤维蛋白转换障碍和血管外纤维蛋白沉积与肺损伤和修复以及肺癌的发病机制有关。 肺上皮细胞通过合成尿激酶（uPA）、尿激酶受体（uPAR）和纤溶酶原激活物抑制剂-1（PA 1 -1）参与血管外纤维蛋白的重塑。 这些分子在肺损伤和瘤形成中的异常表达破坏了局部纤维蛋白周转，增强了局部炎症，并促进了过渡性纤维蛋白的组织化，最终导致纤维化。 我们最近发现uPA诱导肺上皮细胞表达uPAR。 我们现在证明，外源性uPA也诱导uPA和派-1表达这些细胞。 这些研究清楚地表明，肺上皮细胞通过新的途径调节uPA-uPAR-派-1系统，目前对此了解甚少。 我们的初步数据表明，转录后调节有助于uPA介导的自诱导以及uPAR和派-1。 我们的中心假设是，新的途径，uPA调节其自身的表达，以及uPAR和派-1的肺上皮细胞是至关重要的急性肺损伤，其修复和肺癌的发病机制。 我们的目标是阐明uPA诱导这些分子表达的调控机制。 我们将在四个具体目标中实现这一目标。在目的1中，我们将确定是否uPA诱导上皮细胞uPAR在转录或转录后水平，并确定负责的机制。 在目标2中，我们将确定α-凝血酶阻断uPA介导的uPAR诱导的机制。 在目的3和4中，我们将确定uPA分别诱导其自身表达以及PAI-1在肺上皮细胞中表达的机制。 我们将使用广泛的分子，免疫组织化学，蛋白质纯化和细胞培养技术，我们有经验来完成拟议的工作。 这些研究将增加我们对肺上皮调节uPA-uPAR-派-1系统的新机制的理解。 这些信息可能会加速针对肺部疾病（包括急性肺损伤或肺肿瘤）的新的、基于机制的干预措施的开发。

DESCRIPTION (provided by applicant): Disordered fibrin turnover and extravascular fibrin deposition have been implicated in the pathogenesis of lung injury and repair and lung cancer. Lung epithelial cells contribute to remodeling of extravascular fibrin by elaboration of urokinase (uPA), the urokinase receptor (uPAR) and plasminogen activator inhibitor-1 (PAl-1). Abnormal expression of these molecules in lung injury and neoplasia disrupts local fibrin turnover, potentiates local inflammation, and promotes organization of transitional fibrin with eventual fibrosis. We recently found that uPA induces expression of uPAR by lung epithelial cells. We now demonstrate that exogenous uPA also induces uPA and PAI-1 expression by these cells. These studies clearly show that lung epithelial cells regulate the uPA-uPAR-PAI-1 system by novel pathways about which little is currently understood. Our preliminary data show that posttranscriptional regulation contributes to uPA-mediated autoinduction as well as that of uPAR and PAI-1. Our central hypothesis is that novel pathways by which uPA regulates its own expression as well as that of uPAR and PAI-1 by lung epithelial cells are crucial in the pathogenesis of acute lung injury, its repair and lung cancer. Our objective is to elucidate the regulatory mechanisms by which uPA induces expression of these molecules. We will accomplish the objective in four specific aims. In Aim 1, we will determine if uPA induces epithelial cell uPAR at both transcriptional or posttranscriptional levels and define the responsible mechanisms. In Aim 2, we will determine the mechanism by which a-thrombin blocks uPA-mediated uPAR induction. In Aims 3 and 4, we will determine the mechanisms by which uPA induces its own expression as well as that of PAl-1, respectively, in lung epithelial cells. We will use a wide range of molecular, immunohistochemical, protein purification, and cell culture techniques with which we are experienced to complete the proposed work. These studies will increase our understanding of novel mechanisms by which the lung epithelium regulates the uPA-uPAR-PAI-1 system. This information could hasten the development of new, mechanism-based interventions for lung disorders, including acute lung injury or lung neoplasia.