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1-Cys peroxiredoxin (1-cysPrx) is a novel antioxidant enzyme that has been shown to reduce a broad spectrum of peroxides including phospholipid hydroperoxides. We tested the hypothesis that adenovirus-mediated transfer of the 1-cysPrx gene can protect lungs of mice from oxidant injury. Mice infected with AdLacZ/AdNull were used as a control (AdCon). X-galactosidase staining revealed widespread expression of the LacZ gene in airways and lung alveoli. Compared with AdCon, 1-cysPrx expression was increased about twofold at 3 days after adenovirus infection. Mice with increased Prx expression showed less loss of body weight and longer survival during exposure to 100% O2 or to 85% O2 for 4 days followed by 100% O2. At 72 h of 100% O2 exposure, AdPrx infection protected mouse lungs from injury as indicated by less pleural effusion, lower lung wet/dry weight, less protein and fewer nucleated cells in bronchoalveolar lavage fluid, and lower content of thiobarbituric acid-reactive substances and protein carbonyls in lung homogenate. These findings show that increased expression of 1-cysPrx through adenovirus-mediated gene transfer protects mouse lungs from hyperoxic injury and delays death. [ABSTRACT FROM AUTHOR]

1-Cys peroxiredoxin (1-cysPrx), a member of the peroxiredoxin family that contains a single conserved cysteine residue, reduces a broad spectrum of hydroperoxides. We studied changes in 1-cysPrx expression in rat lungs and lung cell lines in response to oxidative stress due to hyperoxia, H[sub 2]O[sub 2], or paraquat. After 60 h of hyperoxia (>95% O[sub 2]), mRNA and protein levels of 1-cysPrx and peroxidase activity were significantly elevated in rat lungs by ∼1.5- to 2-fold compared with the control (P < 0.05). A similar induction of 1-cysPrx was observed in mouse lungs following exposure to O[sub 2] for 63 or 72 h; enzyme induction in mouse lungs was similar for wild-type and glutathione peroxidase 1 genetargeted mice. H[sub 2]O[sub 2] and paraquat treatment induced 1-cysPrx gene expression in L2 cells. Enzyme induction was attenuated by pretreatment with Trolox or N-acetylcysteine. Actinomycin D treatment showed that stability of 1-cysPrx mRNA was not altered in the presence of H[sub 2]O[sub 2] or paraquat, indicating that increased expression with oxidative stress is regulated at the transcriptional level. These data indicate that the antioxidant enzyme 1-cysPrx is induced in lung cells by oxidative stress. [ABSTRACT FROM AUTHOR]

In this work, stable overexpression of peroxiredoxin VI was generated in WI-38 human diploid fibroblasts using a retrovirus-mediated transfection system. Estimation of cell survival showed that peroxiredoxin VI provides a significant protection against tert-butylhydroperoxide- or UVB-caused cytotoxicity. No protection was found against ethanol- or H2O2-caused cytotoxicity. These effects are correlated with the known functions of Prx VI. [ABSTRACT FROM AUTHOR]

Investigates the signaling pathway for nitric oxide generation with oxygenated ischemia in bovine pulmonary artery endothelial cells that were flow adapted in vitro. Assessment of extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylation reactive oxygen species/nitric oxide (NO) generation; Effect of ischemia on ERK1/2 phosphorylation; Result of ischemia in NO generation.

Identifies the temporal relationships among the observed endothelial cell changes with ischemia. Technique used to image the temporal changes occurring in individual endothelial cells; Method used to image the generation of reactive oxygen species (ROS); Fluorescence in subpleural microvasculature in the intact rat lung used in the study; Illustration of the temporal relationships among the changes in membrane potential, ROS and Calcium[sup 2+] with ischemia.

Evaluates the role of a lysosomal-type phospholipase A[sub 2] (aiPLA[sub 2] in the degradation of internalized dipalmitoylphosphatidylcholine (DPPC) and in phospholipid synthesis by the rat lung. DPPC uptake; Effect of MJ33, a specific inhibitor of lung aiPLA[sub 2] on lung synthesis of DPPC; Effect of MJ33 on palmitate incorporated into disaturated phosphatidycholine of lamellar bodies.

The use of agents to inhibit the production of reactive oxygen species (ROS) has been proposed for the treatment of Acute Lung Injury (ALI). However, this approach also inhibits the bactericidal activity of polymorphonuclear leucocytes (PMN) and other cells, raising the possibility of aggravating lung injury in ALI associated with bacterial infection. We used the cecal ligation and puncture (CLP) model of ALI associated with sepsis to investigate the effect of inhibiting NADPH oxidase 2 (NOX2)-derived ROS production, the main source of ROS in lungs. A phospholipase A2 inhibitor called peroxiredoxin 6 inhibitory peptide-2 (PIP-2) was used to inhibit NOX2 activation; the peptide prevents liberation of Rac, a necessary NOX2 co-factor. At 18 h after intravenous treatment with 2 µg PIP-2 /gram body weight (wt), the number of colony-forming bacteria in lungs and peritoneal fluid of mice with CLP was approximately doubled as compared to untreated mice. Treatment with 10 µg PIP-2/g body wt resulted in 100% mortality within 18 h. Antibiotic treatment abolished both the increase in lung bacteria with low dose PIP-2 and the increased mortality with high dose PIP-2. Treatment with PIP-2 plus antibiotics resulted in significantly improved lung histology, decreased PMN infiltration, decreased lung fluid accumulation, and decreased oxidative lung injury compared to antibiotics alone. We conclude that the administration of PIP-2 provides partial protection against lung injury in a model of ALI due to bacterial infection, while concurrent antibiotic treatment abolishes the deleterious effects of PIP-2 on lung bacterial clearance. These results suggest that addition of PIP-2 to the antibiotic regimen is beneficial for treatment of ALI associated with bacterial infection. [ABSTRACT FROM AUTHOR]

Evaluates the role of acidic Ca2+-independent phospholipase A2 (aiPLA2) in phosphatidylcholine choline synthesis by lung epithelium. Transition-state analog enzyme inhibitor 1-hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33); Disaturated phosphatidylcholine (DSPC) synthesis by granular pneumocytes.

Studies the degradation of surfactant protein by alveolar macrophages. Human alveolar proteinosis; Microporous membrane; Ineffectivity of macrophage-conditioned medium.

Examines the inhibition of lung calcium-independent phospholipase A2 by surfactant protein A (SP-A). Inhibition of lamellar body lung phospholipase A2; Alkylation of SP-A; Inactivation of endogenous SP-A in isolated lamellar bodies.

Evaluates morphological localization of a fluorescent analogue of phosphatidylcholine (PC) identified as C12-NBD-PC. Liposomes; Fluorometric analysis; Fluorescent imaging; Colocalization of C12-NBD-PC and various markers; Isolated type II cells, macrophages and lamellar bodies.

Examines the degradation of surfactant protein B by alveolar type II cells. Metabolism of surfactant protein B (SP-B); Cellular degradation of SP-B; Role of alveolar macrophages; Specificity of the metabolism.