EXTRACELLULAR SUPEROXIDE DISMUTASE IN PULMONARY FIBROSIS

肺纤维化中的细胞外超氧化物歧化酶

• 批准号: 6390549
• 负责人: TIM D OURY
• 金额: $ 28.49万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-20 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6390549
• 关键词: collagen; collagenase; enzyme activity; extracellular matrix; genetically modified animals; human tissue; idiopathic pulmonary fibrosis; laboratory mouse; oxidative stress; pathologic process; protein degradation; protein localization; superoxide dismutase

Idiopathic pulmonary fibrosis is a lethal, chronic lung disease with no effective therapy other than lung transplantation. The biochemical mechanisms involved in the pathogenesis of idiopathic pulmonary fibrosis are poorly characterized; however, reactive oxygen species are believed to be involved. Notably, the superoxide anion can activate collagenases as well as directly initiate collagen degradation. Collagen degradation products can stimulate inflammatory responses by neutrophils, resulting in further destruction of the extracellular matrix in the lung. If the inflammatory response is prolonged and/or severe the process may culminate in irreversible pulmonary fibrosis. The antioxidant enzyme extracellular superoxide dismutase (EC-SOD) is found in high concentrations in association with type I collagen in the lung. Thus, it is ideally situated to inhibit superoxide- mediated degradation of type I collagen. This proposal is designed to test the hypothesis that EC-SOD plays a central role in the pathogenesis of pulmonary fibrosis using both a mouse model and diseased human lungs. Transgenic mice that express elevated levels of EC-SOD, and knockout mice that do not express any EC-SOD will be utilized in a bleomycin model of pulmonary fibrosis. Experiments with these mice will allow us to directly determine the importance of EC-SOD in the pathogenesis of pulmonary fibrosis. To test our hypothesis that endogenous alterations in EC-SOD expression and/or biodistribution occur early in fibrotic injuries, de novo synthesis and proteolytic clearance of EC-SOD will be also be monitored in wild type animals treated with bleomycin. Studies will be conducted to delineate specific modifications of collagen in this model of pulmonary fibrosis, which we believe play a central role in the propagation of the injury. The effects of altered EC-SOD levels on this collagen damage will also be investigated to determine the role of EC-SOD in modulating collagen modification/degradation. Finally, immunochemical and biochemical analyses of EC-SOD activity and oxidatively modified collagen in human lungs with idiopathic pulmonary fibrosis will be performed to confirm and extend pathogenic mechanisms derived from the mouse model. When complete these studies will determine the importance of EC-SOD in pulmonary fibrosis. These studies are likely to elucidate novel biochemical mechanisms involved in pulmonary inflammation and fibrosis, and lead to the development of pharmacological agents that regulate these responses.

特发性肺纤维化是一种致命的慢性肺部疾病，除了肺移植以外，没有有效的治疗。 特发性肺纤维化发病机理所涉及的生化机制的特征很差。但是，据信活性氧涉及。 值得注意的是，超氧化阴离子可以激活胶原酶，并直接引发胶原蛋白降解。 胶原蛋白降解产物可以通过中性粒细胞刺激炎症反应，从而进一步破坏肺部细胞外基质。 如果炎症反应延长和/或重度，则该过程可能在不可逆的肺纤维化中达到顶点。 抗氧化酶外细胞超氧化物歧化酶（EC-SOD）的高浓度与肺中的I型胶原蛋白相关。 因此，理想情况下，它可以抑制I型胶原蛋白的超氧化物介导的降解。 该建议旨在检验以下假设：EC-SOD使用小鼠模型和患病的人肺在肺纤维化的发病机理中起着核心作用。 表达EC-SOD水平升高的转基因小鼠和未表达EC-SOD的敲除小鼠将在肺纤维化的博来霉素模型中使用。 这些小鼠的实验将使我们能够直接确定EC-SOD在肺纤维化发病机理中的重要性。 为了检验我们的假设，即在纤维化损伤的早期发生EC-SOD表达和/或生物分布的内源性改变，在用博霉素治疗的野生型动物中也将监测从头合成和EC-SOD的蛋白水解清除率。 在这种肺纤维化模型中，将进行研究以描绘胶原蛋白的特定修饰，我们认为这在损伤的传播中起着核心作用。 还将研究改变EC-SOD水平对这种胶原蛋白损伤的影响，以确定EC-SOD在调节胶原蛋白修饰/降解中的作用。 最后，将对具有特发性肺纤维化的人肺中EC-SOD活性和氧化修饰的胶原蛋白的免疫化学和生化分析进行确认和扩展源自小鼠模型的致病机制。 完成后，这些研究将确定EC-SOD在肺纤维化中的重要性。 这些研究可能会阐明参与肺部炎症和纤维化的新型生化机制，并导致调节这些反应的药理剂的发展。