Extracellular Matrix Components, Oxidants and Antioxidants in Pulmonary Fibrosis

描述(申请人提供)：石棉肺是一种使人衰弱的尘肺和间质性肺病，由吸入石棉纤维引起。石棉肺导致纤维化病理，导致显著的发病率和死亡率。炎症和氧化应激被认为是这种疾病的发病机制之一。细胞外超氧化物歧化酶(EC-SOD)是一种在肺中高度表达的抗氧化酶，已被证明可以保护肺免受氧化剂介导的损伤、炎症和间质纤维化的影响。然而，EC-SOD抑制肺纤维化和炎症的机制尚不清楚。细胞外基质(ECM)成分，如胶原和糖胺多聚糖，对氧化裂解高度敏感，成为炎症细胞的有效趋化剂。已知EC-SOD能紧密结合和定位于糖胺多聚糖，硫酸乙酰肝素(HS)。这一建议的假设是，EC-SOD保护肺免受氧化剂诱导的损伤、炎症和纤维化的一个机制是通过防止肝素/硫酸肝素(HS)在ECM中的氧化碎裂。建议的研究将利用体外肝素/HS裂解试验来研究EC-SOD的保护作用，以及趋化试验来分析氧化裂解的肝素/HS和EC-SOD的炎症反应。最后，利用野生型小鼠、EC-SOD基因敲除小鼠和EC-SOD过表达转基因小鼠，通过生化和组织学分析，研究EC-SOD和HS在石棉处理小鼠肺组织中的体内作用。

DESCRIPTION (provided by applicant): Asbestosis is a debilitating form of pneumoconiosis and interstitial lung disease caused by the inhalation of asbestos fibers. Asbestosis results in fibrotic pathology, which causes significant morbidity and mortality. Inflammation and oxidative stress are known to contribute to the pathogenesis of this disease. Extracellular superoxide dismutase (EC-SOD) is antioxidant enzyme highly expressed in the lung and has been shown to protect the lung from oxidant-mediated damage, inflammation, and interstitial fibrosis. However, the mechanisms through which EC-SOD inhibits pulmonary fibrosis and inflammation remain unclear. Extracellular matrix (ECM) components, such as collagen and glycosaminoglycans, are highly sensitive to oxidative fragmentation and become potent chemoattractants for inflammatory cells. EC-SOD is known to tightly bind and localize to the glycosoaminoglycan, heparan sulfate (HS). The hypothesis of this proposal is that one mechanism in which EC-SOD protects the lung from oxidant-induced damage, inflammation, and fibrosis is by preventing oxidative fragmentation of Heparin/Heparan Sulfate (HS) in the ECM. The proposed studies will utilize in vitro heparin/HS fragmentation assays to study the protective role of EC-SOD and chemotaxis assays to analyze inflammatory responses to oxidatively fragmented heparin/HS and EC- SOD. Finally, wild type mice, EC-SOD knockout and EC-SOD over-expressing transgenic mice will be used to study the in vivo role of EC-SOD and HS in the lungs of asbestos- versus control-treated mice through biochemical and histological analysis.