The Anti-protease and Vitronectin-binding Functions of PAI-1 in Lung Fibrosis

PAI-1在肺纤维化中的抗蛋白酶和玻连蛋白结合功能

• 批准号: 7409660
• 负责人: THOMAS H SISSON
• 金额: $ 35.86万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7409660
• 关键词: Abbreviations; Adherence; Alteplase; Alveolar; Animal Disease Models; Animals; Binding; Binding Sites; Bleomycin; Cell-Matrix Junction; Cells; Characteristics; Cicatrix; Collagen; Data; Development; Disease; Endopeptidases; Epithelial Cells; Epithelium; Extracellular Matrix; Fibroblasts; Fibrosis; Generations; Goals; Hamman-Rich syndrome; Human; In Vitro; Integrins; Localized; Lung; Lung diseases; Mediating; Modeling; Molecular Weight; Mus; Myofibroblast; Pathogenesis; Patients; Peptide Hydrolases; Phenotype; Plasmin; Plasminogen; Plasminogen Activator; Plasminogen Activator Inhibitor 1; Property; Protease Inhibitor; Proteins; Proteolysis; Publishing; Pulmonary Fibrosis; Rate; Relative (related person); Reporting; Research Personnel; Role; Series; Serine Protease; Severities; Specificity; Testing; Therapeutic; Time; Tissues; Urokinase; Urokinase Plasminogen Activator Receptor; Vitronectin; base; fibrogenesis; inhibitor/antagonist; lung injury; migration; mortality; novel therapeutics; programs; receptor binding; therapeutic target

DESCRIPTION (provided by applicant): Idiopathic Pulmonary Fibrosis is a scarring disorder of the lung for which there is no established therapy. Animal models for this disease have implicated plasminogen activator inhibitor-1 (PAI-1) in the pathogenesis. A deficiency of PAI-1, for example, dramatically protects mice from lung collagen accumulation and mortality following a fibrotic insult while the constitutive over-expression of PAI-1 significantly worsens scarring. The tight correlation between the level of PAI-1 and the severity of scarring suggests that PAI-1 inhibition may be a viable therapeutic strategy. To optimally target this molecule, however, it is important to define its mechanism of action in fibrogenesis. PAI-1 is known to have two important functional properties which could influence pulmonary fibrosis. First, it acts as a protease inhibitor with specificity for the plasminogen activators. Through this mechanism, PAI-1 limits plasmin-mediated proteolysis. Second, PAI-1 is capable of binding to vitronectin, a provisional matrix protein. This interaction significantly stabilizes PAI-1's antiprotease activity. In addition, when bound to vitronectin, PAI-1 disrupts cell attachment to and migration across this matrix molecule by sterically inhibiting both integrin and urokinase plasminogen activator receptor binding sites. Our preliminary data, in conjunction with several published reports, suggest that both PAI-1 functions contribute to its influence on fibrogenesis, and these observations have led us to formulate the following hypothesis: The pro-fibrotic effect of PAI-1 following lung injury requires both its anti-protease and vitronectin-binding activity. To test this hypothesis, we propose a series of studies using the bleomycin model of pulmonary fibrosis and primary cultures of mouse alveolar epithelial cells and fibroblasts. Our specific aims are to: 1) determine the requirements of PAI-1's anti-protease and vitronectin-binding functions in the development of bleomycin-induced pulmonary fibrosis, 2) determine the contribution of vitronectin to PAI-1 localization, PAI-1 activity, and pulmonary fibrosis following bleomycin-induced lung injury, and 3) determine the influence of PAI-1 and vitronectin on the in vitro phenotypes of fibroblasts and alveolar epithelial cells. Completion of these specific aims will provide important mechanistic information that will help clarify how PAI-1 facilitates the development of pulmonary fibrosis and whether vitronectin is required for PAI-1 to fully manifest its influence. Ultimately, it is our goal with these studies to help guide the development of new inhibitory agents and/or novel therapeutic strategies for this difficult to treat disease.

描述（由申请人提供）：特发性肺纤维化是一种肺部的疤痕疾病，没有建立的治疗。该疾病的动物模型已暗示纤溶酶原激活剂抑制剂1（PAI-1）在发病机理中。例如，PAI-1的不足会显着保护小鼠免受纤维化损伤后的肺胶原蛋白积累和死亡率，而PAI-1的本构过表达显着恶化了疤痕。 PAI-1水平与疤痕严重程度之间的紧密相关性表明PAI-1抑制作用可能是一种可行的治疗策略。但是，要最佳地靶向该分子，重要的是要定义其在纤维发生中的作用机理。已知PAI-1具有两个重要的功能特性，可能会影响肺纤维化。首先，它充当具有特异性的蛋白酶抑制剂。通过这种机制，PAI-1限制了纤溶酶介导的蛋白水解。其次，PAI-1能够与临时基质蛋白的玻璃体蛋白结合。这种相互作用显着稳定了PAI-1的抗蛋白酶活性。另外，当与玻璃体蛋白结合时，PAI-1通过在空间抑制整合素和尿激酶质激活剂受体受体结合位点，破坏细胞的附着并迁移到该基质分子上。我们的初步数据以及几份已发表的报告都表明，这两种PAI-1功能都有助于其对纤维化的影响，这些观察结果使我们提出了以下假设：肺损伤后PAI-1的促纤维化效应都需要其抗蛋白酶抗蛋白酶抗蛋白酶抗蛋白酶和尿素结合活性。为了检验这一假设，我们提出了一系列研究，使用肺纤维化的博来霉素模型以及小鼠肺泡上皮细胞和成纤维细胞的原发性培养物。我们的具体目的是：1）确定PAI-1的抗蛋白酶和玻霉素结合功能在博霉素诱导的肺纤维化的发展中的需求，2）确定玻璃纤维对PAI-1定位，PAI-1活性，PAI-1活性以及肺部诱导的肺部造成的杀伤和3）的贡献，并确定了PAI造成的静脉结构。成纤维细胞和肺泡上皮细胞的含量。这些特定目的的完成将提供重要的机械信息，这将有助于阐明PAI-1如何促进肺纤维化的发展以及PAI-1是否需要玻璃体素才能充分体现其影响。最终，我们的目标是我们的目标是帮助指导新的抑制剂和/或新型治疗策略的发展，以解决这种难以治疗的疾病。