The overall goal of this application is to understand the role of glutathione (GSH) transport in the subcellular mechanisms of oxidative lung damage. (CF) is a genetic disorder that results in persistent lung inflammation and chronic infection that is implicated in progressive lung injury. Exciting preliminary studies indicate that the genetic defect in the cystic fibrosis transmembrane conductance regulator (CFTR) produces an antioxidant imbalance by decreasing GSH transport into the pulmonary epithelial lining fluid (ELF) and possibly altering GSH transport into the mitochondria. Modulation of GSH transport by the CFTR gene may render the CF patient vulnerable both exogenous and endogenous oxidative stress and thus contribute to the CF pulmonary phenotype. Although evidence exists supporting the role of oxidative stress in the lungs of CF patients, the etiologic and pathogenic relationship between the CFTR gene deficits to oxidative stress has yet to be established. Proposed experiments will delineate the relationship between altered GSH transport and oxidative stress in pulmonary injury associated with CF. The CFTR KO mouse provides a unique way to study pathophysiological mechanisms by which defective GSH transport contributes to antioxidant imbalance and oxidative stress responses in the lung. The CFTR KO recapitulates pulmonary GSH imbalance and oxidative stress of CF patients. It is hypothesized that altered lung GSH transport and metabolism contributes to exaggerated pulmonary oxidative injury and altered host defense. The hypothesis is addressed by the AIMS: (1) To characterize the altered GSH transport, metabolism, utilization, and associated oxidative stress in the lungs of the CFTR KO; (2) Determine whether modulation of GSH transporters can correct the GSH imbalance, oxidative stress, and host defense responses in the CFTR KO; (3) Determine if CFTR KO mice with altered GSH transport are more sensitive to acute lung injury. To accomplish the above aims, the steady-state levels of GSH, GSSG, and GSNO and associated enzyme activities are determined in the lungs of CFTR KO and wild type mice. In addition, markers of oxidative damage to protein, lipid, and DNA are quantitated. GSH transport through ABC cassette proteins will be characterized, modulated, and correlated with changes in oxidative stress and host defense. Lung injury models of infection and oxidative stress are utilized to assess the role of altered GSH transport in lung injury responses. Catalytic antioxidant metalloporphyrins and inhaled GSH are employed to reduce oxidant burden and correct the exaggerated pulmonary oxidative injury response in CF. These studies may emphasize the potential adverse effects of oxidative stress from oxidant air pollutants in sensitive populations with pre-existing lung disease, since a large number of pulmonary diseases (including COPD, ARDS, asthma and pulmonary fibrosis) also have deficits pulmonary ELF GSH ? ?
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