UROKINASE KRINGLE-MEDIATED VASCULAR REMODELING

尿激酶纤溶酶原激活物（uPA）与纤维蛋白溶解有关， 涉及细胞迁移的不同过程如动脉粥样硬化， 血管生成、伤口修复和肿瘤转移。在小鼠中进行的靶向 uPA和uPAR基因的缺失表明uPA诱导跨膜 通过与其结合相关的途径进行信号传导 糖脂锚定受体（uPAR），但到目前为止，这一机制的细节 还没有被阐明。uPA由受体结合生长因子组成 结构域、Kringle结构域（其功能未知）和蛋白酶 域我们实验室最近的研究表明， uPA与血管平滑肌细胞（VSMC）结合并传递信号， 增强uPA介导的VSMC收缩和细胞迁移。此外，本发明还 Kringle的识别介导uPA从细胞表面的清除， 这表明Kringle结构域代表了VSMC中的重要控制点 功能我们现在建议扩大这些研究，并重新审查这些研究。 通过五个更详细地描述了uPA Kringle的性质 相互关联的具体目标。1)我们将描述uPA与 Kringle与低密度脂蛋白受体/α 2巨球蛋白受体 其介导uPA降解。2)我们会分离并鉴定uPA-克林果 VSMC结合蛋白。3)我们将检查克林格介导的信号 VSMC的信号转导通路。4)我们将研究克林格和 VSMC中结合蛋白依赖性和uPAR依赖性信号转导事件 使用能够激活一种或两种途径的uPA变体。5)我们将 研究uPA kringle和kringle结合蛋白在血管内皮细胞中的作用， 血管内创伤大鼠模型的血管壁重塑。这些研究将 提供了一个新描述的uPA介导的信号转导途径的见解 参与平滑肌细胞迁移和血管修复。鉴定 kringle结合蛋白可以提供调节 血管平滑肌细胞增殖和迁移对 动脉粥样硬化和再狭窄。

Urokinase plasminogen activator (uPA) has been implicated in fibrinolysis and diverse processes that involve cell migration such as atherosclerosis, angiogenesis, wound repair, and tumor metastases. Studies in mice with targeted deletion of the genes for uPA and uPAR indicate that uPA induces transmembrane signaling through pathways discrete from those involved in binding to its glycolipid-anchored receptor (uPAR), but to date the details of this mechanism have not been elucidated. uPA is composed of a receptor-binding growth factor domain, a kringle domain, the function of which is unknown, and a protease domain. Recent studies from our laboratories demonstrate that the kringle of uPA binds to vascular smooth muscle cells (VSMC) and delivers a signal that potentiates uPA-mediated VSMC contraction and cell migration. Further, recognition of the kringle mediates clearance of uPA from cell surfaces, suggesting the kringle domain represents an important control point in VSMC function. We now propose to extend these studies and to examine these newly described properties of the uPA kringle in greater detail through five inter-related specific aims. 1) We will characterize the interaction of the uPA kringle with the low-density lipoprotein receptor/alpha2 macroglobulin receptor which mediates uPA degradation. 2) We will isolate and identify the uPA-kringle binding protein on VSMC. 3) We will examine the kringle-mediated signal transduction pathway in VSMC. 4) We will study the interaction between kringle binding protein-dependent and uPAR-dependent signal transduction events in VSMC using uPA variants capable of activation either or both pathways. 5) We will examine the role of the uPA kringle and kringle binding protein in vascular wall remodeling in a rat model of intravascular trauma. These studies will provide insight into a newly described uPA-mediated signal transduction pathway involved in smooth muscle cell migration and vascular repair. Identification of the kringle binding protein may provide an opportunity to modulate the contribution of vascular smooth muscle cell proliferation and migration to atherosclerosis and restenosis.