Patients with lung diseases are commonly treated with high concentrations of oxygen. Supplemental oxygen, while life sustaining, can cause lung injury. The specific cellular, subcellular, and molecular targets of hyperoxic lung injury have not been elucidated, hampering the rational design of specific interventions. Recent studies in premature infants, a population particularly predisposed to hyperoxic lung injury, and in mice exposed to hyperoxia found decreased expression of Clara cell secretory protein (CCSP) and increased reactivity of CCSP with 2,4-dinitrophenylhydrazine (DNPH), indicating oxidation of CCSP. These data suggest that Clara cell function and CCSP expression are adversely affected in hyperoxia. The working hypotheses of this proposal are that maintaining CCSP expression and Clara cell function in hyperoxic animals is protective against hyperoxic lung inflammation and injury and that products of oxidation of CCSP in hyperoxic animals in vivo will be characteristic of a limited number of biologically feasible mechanisms of oxidation studied in vitro.
Specific Aim 1 is to test the hypothesis that intratracheal administration of recombinant CCSP will maintain CCSP expression in mice in the course of exposure to hyperoxia and will be associated with attenuation of hyperoxic lung injury and inflammation. This is based on the evidence that enhanced glutathione reductase (GR) or manganese superoxide dismutase activity in mitochondria protects cells from oxidant stresses, including hyperoxia.
Specific Aim 2 is to test the hypothesis that enhanced expression of GR in the mitochondria of Clara cells in mice will prevent the hyperoxia-induced decrease in CCSP expression in association with increased resistance to hyperoxic lung injury and inflammation. We will enhance Clara cell expression of GR in the mitochondria and cytosol. We also will enhance expression of MnSOD in Clara cells. In these three separate transgenic lines of mice and wild-type mice, we will determine the effects of the enhancements on responses to hyperoxia. Finally, Specific Aim 3 is to test the hypothesis that the specific molecular modifications of CCSP in lung epithelial lining fluid of animals exposed to hyperoxia will be characteristic of the specific mechanisms responsible for oxidation of CCSP, which, in turn, are responsible for loss of immunoreactivity and loss of function of CCSP. The results of the studies described in this proposal are designed to provide the foundation for the rational design of therapeutic interventions in humans.
|Velten, Markus; Heyob, Kathryn M; Rogers, Lynette K et al. (2010) Deficits in lung alveolarization and function after systemic maternal inflammation and neonatal hyperoxia exposure. J Appl Physiol (1985) 108:1347-56|
|Rogers, Lynette K; Tipple, Trent E; Nelin, Leif D et al. (2009) Differential responses in the lungs of newborn mouse pups exposed to 85% or >95% oxygen. Pediatr Res 65:33-8|
|Tipple, Trent E; Welty, Stephen E; Nelin, Leif D et al. (2009) Alterations of the thioredoxin system by hyperoxia: implications for alveolar development. Am J Respir Cell Mol Biol 41:612-9|
|Heyob, Kathryn M; Rogers, Lynette K; Welty, Stephen E (2008) Glutathione reductase targeted to type II cells does not protect mice from hyperoxic lung injury. Am J Respir Cell Mol Biol 39:683-8|
|Tipple, Trent E; Welty, Stephen E; Rogers, Lynette K et al. (2007) Thioredoxin-related mechanisms in hyperoxic lung injury in mice. Am J Respir Cell Mol Biol 37:405-13|
|Park, Min Soo; Rieger-Fackeldey, Esther; Schanbacher, Brandon L et al. (2007) Altered expressions of fibroblast growth factor receptors and alveolarization in neonatal mice exposed to 85% oxygen. Pediatr Res 62:652-7|
|Rogers, Lynette K; Leinweber, Barbara L; Smith, Charles V (2006) Detection of reversible protein thiol modifications in tissues. Anal Biochem 358:171-84|
|Malleske, Daniel T; Rogers, Lynette K; Velluci, Sean M et al. (2006) Hyperoxia increases hepatic arginase expression and ornithine production in mice. Toxicol Appl Pharmacol 215:109-17|
|Welty, Stephen E (2005) Critical issues with clinical research in children: the example of premature infants. Toxicol Appl Pharmacol 207:673-8|
|Rogers, Lynette K; Tamura, Toshiya; Rogers, Bryan J et al. (2004) Analyses of glutathione reductase hypomorphic mice indicate a genetic knockout. Toxicol Sci 82:367-73|