Pathological Consequences of the Plasminogen System

该提案的长期目标是利用基于细胞的体内模型在生理和病理过程中鉴定纤维蛋白溶解系统及其抑制剂的功能并确定其机制。纤维蛋白溶解系统基因缺陷小鼠的可用性导致了对这些蛋白在许多生物事件中的作用的直接分析。研究表明，派-1缺陷减少肿瘤模型中的血管生成。此外，我们的实验室已经表明，内皮细胞（EC）的信号和功能的派-1/LRP相互作用的调节。本申请将进一步阐明派-1对细胞信号传导途径的影响，并确定派-1/LRP相互作用在细胞和生理事件中的重要性。根据这些意见，建议进行以下研究： （1.）确定派-1缺乏对鼠EC JAK/STAT信号传导和细胞周期进程的影响。这些研究将评估STAT和JAK表达谱和增殖野生型（WT）和派-1-/- EC中的激活状态以及STAT核转位的程度。rPAI-1和突变体的加入将决定派-1的哪些功能结构域调节该途径的活化状态。其他研究将确定对细胞迁移的影响。还将研究对细胞周期进程的下游影响。假设派-1缺陷将影响JAK/STAT信号传导和下游细胞周期进程，并且这些作用由派-1/LRP相互作用介导。 （二）表征派-1-/-和uPA-/-/派-1-/-小鼠中心脏纤维化的早期和晚期事件。最近的研究表明，派-1-/-小鼠发生心脏纤维化，这可能是由uPA失调或Akt通路的慢性激活介导的，这是派-1/LRP相互作用改变的结果。拟议的研究将首先表征派-1-/-和uPA-/-/派-1-/-小鼠中的心脏纤维化，以区分心脏纤维化表型中与uPA活性和派-1功能无关的uPA抑制作用。假设心脏纤维化将受到尿激酶活性和PAI-1的其他功能的调节，这将在未来表达派-1功能突变的小鼠的研究中进一步进行。

The long-term goal of this proposal is to identify functions and determine mechanisms of the fibrinolytic system, and its inhibitors, in physiological and pathological processes utilizing cell-based and in vivo models. The availability of mice with deficiencies of genes of the fibrinolytic system has resulted in direct analyses of the role of these proteins in a number of biological events. Studies have indicated that a PAI-1 deficiency diminishes angiogenesis in tumor models. Further, our laboratory has shown that endothelial cell (EC) signaling and function are regulated by PAI-1/LRP interactions. The current application will further elucidate effects of PAI-1 on cell signaling pathways and determine the importance of PAI-1/LRP interactions in both cellular and physiological events. As a result of these observations, the following studies are proposed: (1.) Determine the effects of a PAI-1 deficiency on murine EC JAK/STAT signaling and cell cycle progression. These studies will assess STAT and JAK expression profiles and activation status in proliferating wild-type (WT) and PAI-1-/- EC as well as the extent of nuclear translocation of STAT. The addition of rPAI-1 and mutants will determine which functional domains of PAI-1 regulate the activation status of this pathway. Additional studies will determine effects on cell migration. Downstream effects on cell cycle progression will also be investigated. The hypothesis is that a PAI-1 deficiency will affect JAK/STAT signaling and downstream cell cycle progression, and that these effects are mediated by PAI-1/LRP interactions. (2.) Characterize early and late stage events of cardiac fibrosis in PAI-1-/- and uPA-/-/PAI-1-/- mice. Recent studies have shown that PAI-1-/- mice develop cardiac fibrosis, which may be mediated by dysregulated uPA or chronic activation of the Akt pathway, the result of altered PAI-1/LRP interactions. The studies proposed will initially characterize cardiac fibrosis in PAI-1-/- and uPA-/-/PAI-1-/- mice in order to differentiate effects from uPA activity and PAI-1 functions independent of uPA inhibition in cardiac fibrosis phenotypes. The hypothesis is that cardiac fibrosis will be regulated by urokinase activity and other functions of PAI-I which will be further pursued in future studies of mice expressing functional mutations of PAI-1.