Oxidant and antioxidant balance in the airways and airway diseases

Sputum neutrophil count after bronchial allergen challenge is related to peripheral blood neutrophil chemotaxis in asthma patients

OBJECTIVE

The aim of this study was to estimate relations between sputum neutrophilia and the chemotactic activity of peripheral blood neutrophils after the bronchial allergen challenge in asthma patients.

MATERIALS AND METHODS

Fifteen patients with allergic asthma (AA), 13 patients with allergic rhinitis (AR), all sensitized to Dermatophagoides pteronyssinus, and 8 healthy subjects (HS) underwent bronchial challenge with D. pteronyssinus. Sputum and peripheral blood collection were performed 24 h before, 7 and 24 h after the bronchial challenge. Cell counts were determined by the May-Grünwald-Giemsa method. Neutrophil chemotaxis was analyzed by a flow cytometer; IL-8 levels were measured by ELISA.

RESULTS

Sputum neutrophil count and peripheral blood neutrophil chemotaxis of patients with AA were greater 7 and 24 h after the challenge compared with the baseline values and patients with AR and HS (P < 0.05). Moreover, a significant correlation was found between the neutrophil count in sputum and IL-8 levels, and the chemotactic activity of peripheral blood neutrophils 24 h after the bronchial challenge only the patients with AA (P < 0.05).

CONCLUSIONS

Increased sputum neutrophil count was found to be associated with an enhanced chemotactic activity of peripheral blood neutrophils during allergen-induced late-phase airway inflammation in patients with allergic asthma.

Cellular stress response and pulmonary inflammation

Innate immunity as the first line of the immune system, provides initial protection against various pathogens and infections. Recent studies suggest a link between cell stress response and immune response upon exogenous insults in the lung. The key proteins in cellular stress responses were demonstrated to be involved in the activation and regulation of the immune signaling pathways. Further research on the function of these stress proteins in innate immunity defenses, particularly in pulmonary diseases and inflammation may help to clarify the disease pathogenesis and provide potential therapeutic treatments for various infectious and inflammatory lung diseases.

Detection of cellular damage by hydrogen peroxide using SV40-T2 cells on shear horizontal surface acoustic wave (SH-SAW) sensor

The rat lung epithelial cell line SV40-T2 was used to develop a cellular biosensing system to assay for environmental toxicants. The novel approach on which this system is based involves direct attachment of cultured rat or human cells onto a cell-adhesive matrix on the device through which shear horizontal surface acoustic waves (SH-SAW) are transmitted using 50 MHz SAW resonator. This novel design enables sensitive monitoring of changes of the electrophysical characteristics of cells, such as their conductivity and relative permittivity. A time-dependent change of phase of SAW and change of insertion loss (change of amplitude) were observed when the cells were treated with 0.5 or 1.0 mM H2O2. The change of insertion loss was biphasic, with an early phase (1-3 h) and a late phase (3-6 h). The late phase coincided with the destruction of cell-cell tight junctions detected by measurement of the transepithelial electrical resistance and paracellular permeability; in contrast, the early phase coincided with the destruction of intracellular actin filaments by H2O2. The early-phase effect of H2O2 on phase shift may be attributable to the change of intracellular permittivity by a change of cellular polarity. Immunofluorescence microscopy showed the disappearance of zonula occludens protein 1 from the region of cell-cell contact. These results suggest the correlation between the change of insertion loss as an SAW parameter and the destruction of tight junctions of the cells on the SH-SAW device in the late phase.

Inhibiting lung lining fluid glutathione metabolism with GGsTop as a novel treatment for asthma

Asthma is characterized by airway inflammation. Inflammation is associated with oxidant stress. Airway epithelial cells are shielded from this stress by a thin layer of lung lining fluid (LLF) which contains an abundance of the antioxidant glutathione. LLF glutathione metabolism is regulated by γ-glutamyl transferase (GGT). Loss of LLF GGT activity in the mutant GGT^enu1 mouse causes an increase in baseline LLF glutathione content which is magnified in an IL-13 model of allergic airway inflammation and protective against asthma. Normal mice are susceptible to asthma in this model but can be protected with acivicin, a GGT inhibitor. GGT is a target to treat asthma but acivicin toxicity limits clinical use. GGsTop is a novel GGT inhibitor. GGsTop inhibits LLF GGT activity only when delivered through the airway. In the IL-13 model, mice treated with IL-13 and GGsTop exhibit a lung inflammatory response similar to that of mice treated with IL-13 alone. But mice treated with IL-13 and GGsTop show attenuation of methacholine-stimulated airway hyper-reactivity, inhibition of Muc5ac and Muc5b gene induction, decreased airway epithelial cell mucous accumulation and a fourfold increase in LLF glutathione content compared to mice treated with IL-13 alone. Mice treated with GGsTop alone are no different from that of mice treated with saline alone, and show no signs of toxicity. GGsTop could represent a valuable pharmacological tool to inhibit LLF GGT activity in pulmonary disease models. The associated increase in LLF glutathione can protect lung airway epithelial cells against oxidant injury associated with inflammation in asthma.

Molecular characterization of redox mechanisms in allergic asthma

OBJECTIVE

To investigate the molecular redox mechanisms in allergic asthma and to examine current studies of the disease to provide a basis for further investigation of oxidative stress in allergic asthma and the signaling cascades involved in its pathogenesis.

DATA SOURCES

Through the use of PubMed, a broad biomedical literature review was conducted in the following areas related to the physiology and pathobiology of asthma: redox therapy, reactive oxygen species (ROS), oxidative stress, allergic asthma, and antioxidants.

STUDY SELECTIONS

Studies pertaining to oxidative stress and redox signaling in the molecular pathways of inflammation and hypersensitivity in the pathogenesis of allergic asthma were reviewed.

RESULTS

Allergic asthma is associated with an increase in endogenous ROS formation, leading to oxidative stress-induced damage to the respiratory system and mitigated antioxidant defenses. Exposure to environmental antigens has been shown to stimulate overproduction of ROS, resulting in abnormal physiologic function of DNA, proteins, and lipids that clinically can augment bronchial hyperresponsiveness and inflammation. Through the use of animal and human studies, oxidative stress has been determined to be important in the pathogenesis of allergic asthma. Thus, recent research suggests that the assessment of oxidative stress byproducts represents a novel method by which disease severity can be monitored. In addition, the use of redox-based therapy to attenuate levels of ROS presents a potential strategy to alleviate oxidative stress-induced airway inflammation in patients with asthma.

CONCLUSION

Redox mechanisms of oxidative stress in allergic asthma appear to play a key role in the pathogenesis of the disease and represent a promising therapeutic target.

Pentoxifylline attenuates nitrogen mustard-induced acute lung injury, oxidative stress and inflammation

Nitrogen mustard (NM) is a toxic alkylating agent that causes damage to the respiratory tract. Evidence suggests that macrophages and inflammatory mediators including tumor necrosis factor (TNF)α contribute to pulmonary injury. Pentoxifylline is a TNFα inhibitor known to suppress inflammation. In these studies, we analyzed the ability of pentoxifylline to mitigate NM-induced lung injury and inflammation. Exposure of male Wistar rats (150-174 g; 8-10 weeks) to NM (0.125 mg/kg, i.t.) resulted in severe histopathological changes in the lung within 3d of exposure, along with increases in bronchoalveolar lavage (BAL) cell number and protein, indicating inflammation and alveolar-epithelial barrier dysfunction. This was associated with increases in oxidative stress proteins including lipocalin (Lcn)2 and heme oxygenase (HO)-1 in the lung, along with pro-inflammatory/cytotoxic (COX-2(+) and MMP-9(+)), and anti-inflammatory/wound repair (CD163+ and Gal-3(+)) macrophages. Treatment of rats with pentoxifylline (46.7 mg/kg, i.p.) daily for 3d beginning 15 min after NM significantly reduced NM-induced lung injury, inflammation, and oxidative stress, as measured histologically and by decreases in BAL cell and protein content, and levels of HO-1 and Lcn2. Macrophages expressing COX-2 and MMP-9 also decreased after pentoxifylline, while CD163+ and Gal-3(+) macrophages increased. This was correlated with persistent upregulation of markers of wound repair including pro-surfactant protein-C and proliferating nuclear cell antigen by Type II cells. NM-induced lung injury and inflammation were associated with alterations in the elastic properties of the lung, however these were largely unaltered by pentoxifylline. These data suggest that pentoxifylline may be useful in treating acute lung injury, inflammation and oxidative stress induced by vesicants.

Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey

Background

Increased bronchial responsiveness is characteristic of asthma. Gas cooking, which is a major indoor source of the highly oxidant nitrogen dioxide, has been associated with respiratory symptoms and reduced lung function. However, little is known about the effect of gas cooking on bronchial responsiveness and on how this relationship may be modified by variants in the genes GSTM1, GSTT1 and GSTP1, which influence antioxidant defences.

Methods

The study was performed in subjects with forced expiratory volume in one second at least 70% of predicted who took part in the multicentre European Community Respiratory Health Survey, had bronchial responsiveness assessed by methacholine challenge and had been genotyped for GSTM1, GSTT1 and GSTP1-rs1695. Information on the use of gas for cooking was obtained from interviewer-led questionnaires. Effect modification by genotype on the association between the use of gas for cooking and bronchial responsiveness was assessed within each participating country, and estimates combined using meta-analysis.

Results

Overall, gas cooking, as compared with cooking with electricity, was not associated with bronchial responsiveness (β=−0.08, 95% CI −0.40 to 0.25, p=0.648). However, GSTM1 significantly modified this effect (β for interaction=−0.75, 95% CI −1.16 to −0.33, p=4×10⁻⁴), with GSTM1 null subjects showing more responsiveness if they cooked with gas. No effect modification by GSTT1 or GSTP1-rs1695 genotypes was observed.

Conclusions

Increased bronchial responsiveness was associated with gas cooking among subjects with the GSTM1 null genotype. This may reflect the oxidant effects on the bronchi of exposure to nitrogen dioxide.

Fish oil supplementation decreases oxidative stress but does not affect platelet-activating factor bioactivity in lungs of asthmatic rats

Dietary fish oil supplementation increases the content of n-3 polyunsaturated fatty acids (PUFA) in cellular membranes. The highly unsaturated nature of n-3 PUFA could result in an enhanced lipid peroxidation in the oxidative environment characteristic of asthma. The oxidative reaction cascade culminates in an increased production of components associated to oxidative stress and of an important proinflammatory mediator platelet-activating factor (PAF)-like lipid. We evaluated the effect of fish oil supplementation in asthmatic rats upon the PAF bioactivity and parameters related to oxidative stress in the lung. Fish oil supplementation of asthmatic rats resulted in lower concentrations of nitrite (1.719 ± 0.137 vs. 2.454 ± 0.163 nmol/mL) and lipid hydroperoxide (72.190 ± 7.327 vs. 120.200 ± 11.270 nmol/mg protein). In asthmatic animals, fish oil increased the activities of superoxide dismutase (EC 1.15.1.1) (33.910 ± 2.325 vs. 24.110 ± 0.618 U/mg protein) and glutathione peroxidase (EC 1.11.1.9) (164.100 ± 31.250 vs. 12.590 ± 5.234 U/mg protein). However, fish oil did not affect PAF bioactivity in lung tissue of asthmatic rats (0.545 ± 0.098 340/380 vs. 0.669 ± 0.101 340/380 nm ratio). Considering the two-step process--oxidative stress and PAF bioactivity--fish oil exhibited a divergent action on these aspects of asthmatic inflammation, since the supplement lowered oxidative stress in the lungs of asthmatic rats, presenting an antioxidant effect, but did not affect PAF bioactivity. This suggests a dual effect of fish oil on oxidative stress and inflammation in asthma.

Proteomic identification of novel differentiation plasma protein markers in hypobaric hypoxia-induced rat model

Background

Hypobaric hypoxia causes complex changes in the expression of genes, including stress related genes and corresponding proteins that are necessary to maintain homeostasis. Whereas most prior studies focused on single proteins, newer methods allowing the simultaneous study of many proteins could lead to a better understanding of complex and dynamic changes that occur during the hypobaric hypoxia.

Methods

In this study we investigated the temporal plasma protein alterations of rat induced by hypobaric hypoxia at a simulated altitude of 7620 m (25,000 ft, 282 mm Hg) in a hypobaric chamber. Total plasma proteins collected at different time points (0, 6, 12 and 24 h), separated by two-dimensional electrophoresis (2-DE) and identified using matrix assisted laser desorption ionization time of flight (MALDI-TOF/TOF). Biological processes that were enriched in the plasma proteins during hypobaric hypoxia were identified using Gene Ontology (GO) analysis. According to their properties and obvious alterations during hypobaric hypoxia, changes of plasma concentrations of Ttr, Prdx-2, Gpx -3, Apo A-I, Hp, Apo-E, Fetub and Nme were selected to be validated by Western blot analysis.

Results

Bioinformatics analysis of 25 differentially expressed proteins showed that 23 had corresponding candidates in the database. The expression patterns of the eight selected proteins observed by Western blot were in agreement with 2-DE results, thus confirming the reliability of the proteomic analysis. Most of the proteins identified are related to cellular defense mechanisms involving anti-inflammatory and antioxidant activity. Their presence reflects the consequence of serial cascades initiated by hypobaric hypoxia.

Conclusion/Significance

This study provides information about the plasma proteome changes induced in response to hypobaric hypoxia and thus identification of the candidate proteins which can act as novel biomarkers.

Association of the CAT-262C>T polymorphism with asthma in smokers and the nonemphysematous phenotype of chronic obstructive pulmonary disease

BACKGROUND

Catalase (CAT) is a part of the active antioxidant defense system and has been studied with regard to its association with asthma and chronic obstructive pulmonary disease (COPD), which are heterogeneous obstructive pulmonary diseases characterized by chronic airway inflammation. We hypothesized that the CAT gene might be involved in the common pathogenesis underlying asthma and COPD.

OBJECTIVE

To evaluate the association of CAT polymorphisms with specific phenotypes of asthma and COPD to identify the common underlying pathophysiologic mechanisms of these 2 diseases.

METHODS

The -262C>T and -21A>T polymorphisms in the CAT gene were genotyped in 493 individuals with asthma, 265 with COPD, and 1,076 healthy controls. Asthmatic patients were categorized according to smoking status (smokers and nonsmokers) and age at onset (early onset and adult onset) as part of a case-control study. In patients with COPD, visual scoring (computed tomographic score) was assessed to determine emphysema severity, which was used to evaluate associations with CAT gene polymorphisms.

RESULTS

Overall, the -262C>T and -21A>T polymorphisms were not associated with asthma. However, the -262CT+TT genotype was significantly associated with adult-onset asthma in smokers (P = .005), and a significant interaction between smoking status and the effect of -262C>T genotype on asthma were observed (P = .01). In patients with COPD, this genotype was significantly associated with a low computed tomographic score (P = .03), which indicates a nonemphysematous type of COPD.

CONCLUSION

The present study indicates that the CAT gene is involved in the common pathogenesis underlying adult-onset asthma in smokers and the nonemphysematous type of COPD.

Antioxidant defense enzyme genes and asthma susceptibility: gender-specific effects and heterogeneity in gene-gene interactions between pathogenetic variants of the disease

Oxidative stress resulting from an increased amount of reactive oxygen species and an imbalance between oxidants and antioxidants plays an important role in the pathogenesis of asthma. The present study tested the hypothesis that genetic susceptibility to allergic and nonallergic variants of asthma is determined by complex interactions between genes encoding antioxidant defense enzymes (ADE). We carried out a comprehensive analysis of the associations between adult asthma and 46 single nucleotide polymorphisms of 34 ADE genes and 12 other candidate genes of asthma in Russian population using set association analysis and multifactor dimensionality reduction approaches. We found for the first time epistatic interactions between ADE genes underlying asthma susceptibility and the genetic heterogeneity between allergic and nonallergic variants of the disease. We identified GSR (glutathione reductase) and PON2 (paraoxonase 2) as novel candidate genes for asthma susceptibility. We observed gender-specific effects of ADE genes on the risk of asthma. The results of the study demonstrate complexity and diversity of interactions between genes involved in oxidative stress underlying susceptibility to allergic and nonallergic asthma.

The Physiology and Genetics of Oxidative Stress in Mycobacteria

During infection, Mycobacterium tuberculosis is exposed to a diverse array of microenvironments in the human host, each with its own unique set of redox conditions. Imbalances in the redox environment of the bacillus or the host environment serve as stimuli, which could regulate virulence. The ability of M. tuberculosis to evade the host immune response and cause disease is largely owing to the capacity of the mycobacterium to sense changes in its environment, such as host-generated gases, carbon sources, and pathological conditions, and alter its metabolism and redox balance accordingly for survival. In this article we discuss the redox sensors that are, to date, known to be present in M. tuberculosis , such as the Dos dormancy regulon, WhiB family, anti-σ factors, and MosR, in addition to the strategies present in the bacillus to neutralize free radicals, such as superoxide dismutases, catalase-peroxidase, thioredoxins, and methionine sulfoxide reductases, among others. M. tuberculosis is peculiar in that it appears to have a hierarchy of redox buffers, namely, mycothiol and ergothioneine. We discuss the current knowledge of their biosynthesis, function, and regulation. Ergothioneine is still an enigma, although it appears to have distinct and overlapping functions with mycothiol, which enable it to protect against a wide range of toxic metabolites and free radicals generated by the host. Developing approaches to quantify the intracellular redox status of the mycobacterium will enable us to determine how the redox balance is altered in response to signals and environments that mimic those encountered in the host.

H2O2 stimulates cystic fibrosis transmembrane conductance regulator through an autocrine prostaglandin pathway, using multidrug-resistant protein-4

Cystic fibrosis transmembrane conductance regulator (CFTR) activity is essential for the maintenance of airway surface liquid depth, and therefore mucociliary clearance. Reactive oxygen species, increased during inflammatory airway diseases, alter CFTR activity. Here, H2O2 levels in the surface liquid of normal human bronchial epithelial cultures differentiated at the air-liquid interface were estimated, and H2O2-mediated changes in CFTR activity were examined. In Ussing chambers, H2O2-induced anion currents were sensitive to the CFTR inhibitors CFTRinh172 and GlyH-101. These currents were absent in cells from patients with cystic fibrosis. Responses to greater than 500 μM H2O2 were transient. Cyclooxygenase inhibitors blocked the H2O2 response, as did EP1 and EP4 receptor antagonists. A multidrug-resistant protein (MRP) inhibitor and short hairpin RNA directed against MRP4 blocked H2O2 responses. EP1 and EP4 agonists mimicked H2O2 in both control and MRP4 knockdown cells. Thus, H2O2 activates the synthesis, export, and binding of prostanoids via EP4 and, interestingly, EP1 receptors in normal, differentiated human airway epithelial cells to activate cyclic adenosine monophosphate pathways that in turn activate CFTR channels in the apical membrane.

Reactive oxygen species in inflammation and tissue injury

Abstract Reactive oxygen species (ROS) are key signaling molecules that play an important role in the progression of inflammatory disorders. An enhanced ROS generation by polymorphonuclear neutrophils (PMNs) at the site of inflammation causes endothelial dysfunction and tissue injury. The vascular endothelium plays an important role in passage of macromolecules and inflammatory cells from the blood to tissue. Under the inflammatory conditions, oxidative stress produced by PMNs leads to the opening of inter-endothelial junctions and promotes the migration of inflammatory cells across the endothelial barrier. The migrated inflammatory cells not only help in the clearance of pathogens and foreign particles but also lead to tissue injury. The current review compiles the past and current research in the area of inflammation with particular emphasis on oxidative stress-mediated signaling mechanisms that are involved in inflammation and tissue injury.

Inhalation of glycopyrronium inhibits cigarette smoke-induced acute lung inflammation in a murine model of COPD

Glycopyrronium bromide (GB) is a muscarinic receptor antagonist that has been used as a long-acting bronchodilator in chronic obstructive pulmonary disease (COPD) patients. The aim of this study was to investigate the anti-inflammatory activity of inhaled GB in a cigarette smoke-induced acute lung inflammation mouse model. We found that aerosol pre-treatment with GB suppresses the accumulation of neutrophils and macrophages in the bronchoalveolar lavage fluid (BALF) in cigarette smoke (CS)-exposed mice. GB at doses of 300 and 600 μg/ml significantly inhibited the CS-induced increases in the mRNA and protein expression levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1 and transforming growth factor (TGF)-β1 in lung tissues and the BALF. Moreover, GB at a dose of 600 μg/ml significantly inhibited the CS-induced changes in glutathione (GSH) and myeloperoxidase (MPO) activities in the BALF, decreased the CS-induced expression of matrix metalloproteinases (MMP)-9, and increased the CS-induced expression of tissue inhibitor of metalloproteinases (TIMP)-1, as determined through the immunohistochemical staining of lung tissue. Our results demonstrate the beneficial effects of inhaled GB on the inflammatory reaction in COPD.

Imbalance in redox status is associated with tumor aggressiveness and poor outcome in lung adenocarcinoma patients

PURPOSE

The expression levels of human antioxidant genes (HAGs) and oxidative markers were investigated in light of lung adenocarcinoma aggressiveness and patient outcome.

METHODS

We assayed in vitro the tumoral invasiveness and multidrug resistance in human lung adenocarcinoma (AdC) cell lines (EKVX and A549). Data were associated with several redox parameters and differential expression levels of HAG network. The clinicopathological significance of these findings was investigated using microarray analysis of tumor tissue and by immunohistochemistry in archival collection of biopsies.

RESULTS

An overall increased activity (expression) of selected HAG components in the most aggressive cell line (EKVX cells) was observed by bootstrap and gene set enrichment analysis (GSEA). In vitro validation of oxidative markers revealed that EKVX cells had high levels of oxidative stress markers. In AdC cohorts, GSEA of microarray datasets showed significantly high levels of HAG components in lung AdC samples in comparison with normal tissue, in advanced stage compared with early stage and in patients with poor outcome. Cox multivariate regression analysis in a cohort of early pathologic (p)-stage of AdC cases showed that patients with moderate levels of 4-hydroxynonenal, a specific and stable end product of lipid peroxidation, had a significantly less survival rate (hazard ratio of 8.87) (P < 0.05).

CONCLUSIONS

High levels of oxidative markers are related to tumor aggressiveness and can predict poor outcome of early-stage lung adenocarcinoma patients.

Epistatic effects of multiple receptor genes on pathophysiology of asthma - its limits and potential for clinical application

To date, genome-wide association studies (GWAS) permit a comprehensive scan of the genome in an unbiased manner, with high sensitivity, and thereby have the potential to identify candidate genes for the prevalence or development of multifactorial diseases such as bronchial asthma. However, most studies have only managed to explain a small additional percentage of hereditability estimates, and often fail to show consistent results among studies despite large sample sizes. Epistasis is defined as the interaction between multiple different genes affecting phenotypes. By applying epistatic analysis to clinical genetic research, we can analyze interactions among more than 2 molecules (genes) considering the whole system of the human body, illuminating dynamic molecular mechanisms. An increasing number of genetic studies have investigated epistatic effects on the risk for development of asthma. The present review highlights a concept of epistasis to overcome traditional genetic studies in humans and provides an update of evidence on epistatic effects on asthma. Furthermore, we review concerns regarding recent trends in epistatic analyses from the perspective of clinical physicians. These concerns include biological plausibility of genes identified by computational statistics, and definition of the diagnostic label of 'physician-diagnosed asthma'. In terms of these issues, further application of epistatic analysis will prompt identification of susceptibility of diseases and lead to the development of a new generation of pharmacological strategies to treat asthma.

The role of neutrophils in the immune system: an overview

Neutrophils, also known as polymorphonuclear leukocytes (PMNs), have long been considered as the short-lived, nonspecific white cells that form pus-and also happen to kill invading microbes. Indeed, neutrophils were often neglected (and largely not considered) as immune cells. This historic view of neutrophils has changed considerably over the past several decades, and we know now that, in addition to playing the predominant role in the clearance of bacteria and fungi, they play a major role in shaping the host response to infection and immune system homeostasis. The change in our view of the role of neutrophils in the immune system has been due in large part to the study of these cells in vitro. Such work has been made possible by new and/or improved methods and approaches used to investigate neutrophils. These methods are the focus of this volume.

Nitration of protein without allergenic potential triggers modulation of antioxidant response in type II pneumocytes

Inhalation of nitrogen and reactive oxygen species (ROS) is known to induce lung inflammation, which is prevented by enzymatic and nonenzymatic antioxidant systems. These agents form nitrated allergens that were shown to enhance allergenicity. The aim of this study was to examine the influence of nitrated proteins on inflammation and antioxidant status of the lung. Ovalbumin (OVA) in nitrated form (nOVA) was intraperitoneally (ip) injected in mice for sensitization and in nitrated or unmodified form for challenge to induce allergic bronchial inflammation. To study the allergen potential of unrelated protein and verify cross-reactivity, nitrated and unmodified keyhole limpet hemocyanin (nKLH, KLH) was used for challenge. Challenge with OVA or nOVA reduced lung function and increased eosinophilia and protein content in bronchoalveolar lavage fluid (BALF). Challenge with nitrated or native OVA or KLH elevated glutathione (GSH) ratio in type II pneumocytes. Reduced mRNA expression of glutathione peroxidase (GPX) 3, glutathione reductase (GR), superoxide dismutase (SOD) 2, and catalase (CAT) was most prominent after challenge with nitrated OVA and nitrated KLH, respectively. Challenge with nOVA enhanced SOD1 mRNA reduction. Immunostaining of GPX 3 and SOD2 increased after challenge with OVA or nOVA, while reactivity of GR and reactivity of SOD2 were reduced after challenge with KLH or nKLH. SOD1 immunostaining was diminished after challenge with nonnitrated OVA or KLH. CAT immunoreaction was similar in all groups. Nitrated proteins without allergenic potential triggered mRNA reduction of antioxidants in type II cells after sensitization with a nitrated allergen but did not induce bronchial inflammation.

Oxidants and redox signaling in acute lung injury

Acute lung injury (ALI) and its more severe form of clinical manifestation, the acute respiratory distress syndrome is associated with significant dysfunction in air exchange due to inflammation of the lung parenchyma. Several factors contribute to the inflammatory process, including hypoxia (inadequate oxygen), hyperoxia (higher than normal partial pressure of oxygen), inflammatory mediators (such as cytokines), infections (viral and bacterial), and environmental conditions (such as cigarette smoke or noxious gases). However, studies over the past several decades suggest that oxidants formed in the various cells of the lung including endothelial, alveolar, and epithelial cells as well as lung macrophages and neutrophils in response to the factors mentioned above mediate the pathogenesis of ALI. Oxidants modify cellular proteins, lipids, carbohydrates, and DNA to cause their aberrant function. For example, oxidation of lipids changes membrane permeability. Interestingly, recent studies also suggest that spatially and temporally regulated production of oxidants plays an important role antimicrobial defense and immunomodulatory function (such as transcription factor activation). To counteract the oxidants an arsenal of antioxidants exists in the lung to maintain the redox status, but when overwhelmed tissue injury and exacerbation of inflammation occurs. We present below the current understanding of the pathogenesis of oxidant-mediated ALI.

Deficiency of gp91phox inhibits allergic airway inflammation

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a multienzyme complex, is the major source for production of reactive oxygen species (ROS). ROS are increased in allergic diseases, such as asthma, but the role of ROS in disease pathogenesis remains uncertain. We hypothesized that mice unable to generate ROS via the NADPH oxidase pathway would have decreased allergic airway inflammation. To test this hypothesis, we studied gp91phox(-/-) mice in a model of allergic airway inflammation after sensitization and challenge with ovalbumin. Serum, bronchoalveolar lavage fluid, and lungs were then examined for evidence of allergic inflammation. We found that mice lacking a functional NADPH oxidase complex had significantly decreased ROS production and allergic airway inflammation, compared with wild-type (WT) control animals. To determine the mechanism by which allergic inflammation was inhibited by gp91phox deficiency, we cultured bone marrow-derived dendritic cells from WT and gp91phox(-/-) mice and activated them with LPS. IL-12 expression was significantly increased in the gp91phox(-/-) bone marrow-derived dendritic cells, suggesting that the cytokine profile produced in the absence of gp91phox enhanced the conditions leading to T helper (Th) type 1 differentiation, while inhibiting Th2 polarization. Splenocytes from sensitized gp91phox(-/-) animals produced significantly less IL-13 in response to ovalbumin challenge in vitro compared with splenocytes from sensitized WT mice, suggesting that NADPH oxidase promotes allergic sensitization. In contrast, inflammatory cytokines produced by T cells cultured from WT and gp91phox(-/-) mice under Th0, Th1, Th2, and Th17 conditions were not significantly different. This study demonstrates the importance of NADPH oxidase activity and ROS production in a murine model of asthma.

Genetic variation in antioxidant enzymes, cigarette smoking, and longitudinal change in lung function

Antioxidant enzymes play an important role in the defense against oxidative stress in the lung and in the pathogenesis of chronic obstructive pulmonary disease (COPD). Sequence variation in genes encoding antioxidant enzymes may alter susceptibility to COPD by affecting longitudinal change in lung function in adults. We genotyped 384 sequence variants in 56 candidate genes in 1281 African American and 1794 European American elderly adults in the Health, Aging, and Body Composition study. Single-marker associations and gene-by-smoking interactions with rate of change in FEV₁ and FEV₁/FVC were evaluated using linear mixed-effects models, stratified by race/ethnicity. In European Americans, rs17883901 in GCLC was statistically significantly associated with rate of change in FEV₁/FVC; the recessive genotype (TT) was associated with a 0.9% per year steeper decline (P = 4.50 × 10(-5)). Statistically significant gene-by-smoking interactions were observed for variants in two genes in European Americans: the minor allele of rs2297765 in mGST3 attenuated the accelerated decline in FEV₁/FVC in smokers by 0.45% per year (P = 1.13 × 10(-4)); for participants with greater baseline smoking pack-years, the minor allele of rs2073192 in IDH3B was associated with an accelerated decline in FEV₁/FVC (P = 2.10 × 10(-4)). For both genes, nominally significant interactions (P < 0.01) were observed at the gene level in African Americans (P = 0.007 and 4.60 × 10(-4), respectively). Nominally significant evidence of association was observed for variants in SOD3 and GLRX2 in multiple analyses. This study identifies two novel genes associated with longitudinal lung function phenotypes in both African and European Americans and confirms a prior finding for GCLC. These findings suggest novel mechanisms and molecular targets for future research and advance the understanding of genetic determinants of lung function and COPD risk.

Renal injury and Nrf2 modulation in mouse kidney following chronic exposure to TiO₂ nanoparticles

TiO₂ nanoparticles (NPs) are used in the food industry but have potential toxic effects in humans and animals. TiO₂ NPs impair renal function and cause oxidative stress and renal inflammation in mice, associated with inhibition of nuclear factor erythroid-2-related factor 2 (Nrf2), which regulates genes encoding many antioxidants and detoxifying enzymes. This study determined whether TiO₂ NPs activated the Nrf2 signaling pathway. Mice exhibited accumulation of reactive oxygen species and peroxidation of lipid, protein, and DNA in the kidney, coupled with renal dysfunction, glutathione depletion, inflammatory cell infiltration, fatty degeneration, and apoptosis. These were associated with increased expression of NOX4, cyclooxygenase-2, and nuclear factor-κB. Oxidative stress and inflammation were accompanied by decreased expression of Nrf2 and down-regulation of its target gene products including heme oxygenase 1, glutamate-cysteine ligase catalytic subunit, and glutathione S-transferase. Chronic TiO₂ NP exposure is associated with suppression of Nrf2, which contributes to the pathogenesis of oxidative stress and inflammation.

Endocrine disruptors found in food contaminants enhance allergic sensitization through an oxidative stress that promotes the development of allergic airway inflammation

In the past few decades, there has been a significant increase in incidence of allergic diseases. The hygiene hypothesis may provide some clues to explain this rising trend, but it may also be attributable to other environmental factors that exert a proallergic adjuvant effects. However, there is limited information on the risks of developing allergic asthma and related diseases through the ingestion of environmental chemicals found in food contaminants. In the present study, we have shown that oral administration of tributyltin, used as a model environmental chemical, induced oxidative-stress status in the bronchial lymph node, mesenteric lymph node and spleen, but not in the lung, where the initial step of allergic asthma pathogenesis takes place. Mice exposed to tributyltin exhibited heightened Th2 immunity to the allergen with more severe airway inflammation. Tributyltin also induced Treg cells apoptosis preferentially over non-Treg cells. All these effects of tributyltin exposure were canceled by the administration of glutathione monoethyl ester. Meanwhile, tributyltin did not affect airway inflammation of mice transferred with allergen-specific Th2 cells. Collectively, these results suggest that tributyltin exerts its pathological effect during the sensitization phase through oxidative stress that enhances the development of allergic diseases. The current study dissects the pathogenic role of oxidative stress induced by oral exposure to an environmental chemical during the sensitization phase of allergic airway inflammation and would be important for developing therapeutics for prevention of allergic diseases.

Biomarkers in Exhaled Breath Condensate and Serum of Chronic Obstructive Pulmonary Disease and Non-Small-Cell Lung Cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer are leading causes of deaths worldwide which are associated with chronic inflammation and oxidative stress. Lung cancer, in particular, has a very high mortality rate due to the characteristically late diagnosis. As such, identification of novel biomarkers which allow for early diagnosis of these diseases could improve outcome and survival rate. Markers of oxidative stress in exhaled breath condensate (EBC) are examples of potential diagnostic markers for both COPD and non-small-cell lung cancer (NSCLC). They may even be useful in monitoring treatment response. In the serum, S100A8, S100A9, and S100A12 of the S100 proteins are proinflammatory markers. They have been indicated in several inflammatory diseases and cancers including secondary metastasis into the lung. It is highly likely that they not only have the potential to be diagnostic biomarkers for NSCLC but also prognostic indicators and therapeutic targets.

Reactive Oxygen Species in Chronic Rhinosinusitis and Secondhand Smoke Exposure

Objective

Reactive oxygen species (ROS) can potentiate cellular injury and inflammation. This study aimed to (1) assess the presence of reactive oxygen species in the sinus tissue of patients with chronic rhinosinusitis (CRS) and (2) assess the impact of secondhand smoke (SHS) exposure on reactive oxygen species (ROS) production.

Study Design

Retrospective cohort study.

Setting

Academic medical center.

Subjects and Methods

Sinus tissue samples from patients undergoing sinus surgery were analyzed using diaminobenzidine (DAB) staining to assess for ROS. Stained specimens were photographed at random by a blinded photographer and then quantified by 3 blinded graders. The patient’s SHS exposure was determined by hair nicotine levels. Results were compared between non–smoke exposed cohorts and those exposed to secondhand smoke and by diagnosis.

Results

Sixty-nine adults undergoing sinus surgery were included in the study. For the non-SHS-exposed cohorts, chronic rhinosinusitis with nasal polyps (CRSwNP) had the highest number of DAB+ cells/high-powered field (hpf) followed by chronic rhinosinusitis without nasal polyps (CRSsNP) and controls. When comparing the control patients to their SHS-exposed counterparts, SHS exposure yielded statistically significantly higher levels of DAB-positive cells/hpf. SHS exposure did not affect DAB staining in CRSsNP or CRSwNP patients.

Conclusion

ROS are differentially expressed in various subtypes of CRS. SHS exposure increases ROS in sinus tissue of control patients, but the clinical significance of this is unclear.

Molecular mechanisms of reactive oxygen species-related pulmonary inflammation and asthma

Asthma is a highly relevant disorder that can be induced by many environmental factors such as allergens and pollutants. One of the most critical pathological symptoms of asthma is airway inflammation. In order to identify a cause of respiratory inflammation, we thoroughly examine the unique role of reactive oxygen species (ROS). Evidence supports that the inhalation of aggravating compounds such as allergens can promote the increased generation of ROS. Accordingly, ROS have a proven role in the cellular signaling cascades of many respiratory diseases that cause respiratory inflammation, including asthma. Although there is no known cure for asthma, current treatments effectively lessen the inflammation symptom. Based on the investigations of asthma pathogenesis and the mechanism of ROS formation, we have identified several novel anti-inflammatory therapeutic treatments, shedding light on a fundamental understanding for the cure of this disorder. In this review, we will outline the pathogenesis of asthma and its relationship to ROS, oxidative stress, and pulmonary inflammation.

TRPM2 channels are not required for acute airway inflammation in OVA-induced severe allergic asthma in mice

Background

Airway inflammation and asthma have been linked to oxidative stress and the melastatin-related transient receptor potential cation channel, member 2 (TRPM2), which can be activated by reactive oxygen species (ROS), has emerged as a potential therapeutic target for inflammatory diseases.

Objective

Using TRPM2 deficient (TRPM2^-/-) mice, we investigated whether the TRPM2 ion channel, which mediates calcium (Ca²⁺) influx and lysosomal Ca²⁺ release, plays a role in the pathophysiology of severe allergic asthma in mouse.

Methods

Severe allergic asthma was initiated in wild type (WT) and TRPM2^-/- mice by repeated sensitization with ovalbumin (OVA)/aluminum hydroxide on Days 0, 7 and 14, followed by intranasal challenge on Days 21, 22 and 23. Mice were investigated for the presence of airway responsiveness, airway inflammation, production of allergen-specific antibodies, cytokine response and lung pathology.

Results

The absence of TRPM2 channels has no obvious effect on major etiologic markers of severe allergic asthma in this mouse model. Neither airway resistance nor mucus production are affected in TRPM2^-/- mice. TRPM2 channel ablation also does not alter airway inflammation or immunocyte infiltration and does not affect antibody response or cytokine levels.

Conclusions

TRPM2 is not required for airway inflammation in OVA-induced severe allergic asthma in mice. Accordingly, TRPM2 might not be a suitable therapeutic target for airway inflammation caused by allergens in humans.

Inflammatory signalings involved in airway and pulmonary diseases

In respiratory diseases, there is an increased expression of multiple inflammatory proteins in the respiratory tract, including cytokines, chemokines, and adhesion molecules. Chemokines have been shown to regulate inflammation and immune cell differentiation. Moreover, many of the known inflammatory target proteins, such as matrix metalloproteinase-9 (MMP-9), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase-2 (COX-2), and cytosolic phospholipase A₂ (cPLA₂), are associated with airway and lung inflammation in response to various stimuli. Injuriously environmental stimuli can access the lung through either the airways or the pulmonary and systemic circulations. The time course and intensity of responses by resident and circulating cells may be regulated by various inflammatory signalings, including Src family kinases (SFKs), protein kinase C (PKC), growth factor tyrosine kinase receptors, nicotinamide adenine dinucleotide phosphate (NADPH)/reactive oxygen species (ROS), PI3K/Akt, MAPKs, nuclear factor-kappa B (NF-κB), activator protein-1 (AP-1), and other signaling molecules. These signaling molecules regulate both key inflammatory signaling transduction pathways and target proteins involved in airway and lung inflammation. Here, we discuss the mechanisms involved in the expression of inflammatory target proteins associated with the respiratory diseases. Knowledge of the mechanisms of inflammation regulation could lead to the pharmacological manipulation of anti-inflammatory drugs in the respiratory diseases.

The effect of lead acetate on oxidative stress and antioxidant status in rat bronchoalveolar lavage fluid and lung tissue

Despite the wide spread of lead environmental pollution, the effect of this heavy metal on respiratory disease was not shown yet. In respect to increased oxidative stress is an important mechanism in the pathogenesis of respiratory disease, the present study was designed to examine the association between lead toxicity and lung disease via measuring oxidative stress biomarkers in bronchoalveolar lavage fluid (BALF) and lung tissue of rat. For this aim, 32 rats were divided into the following groups of eight animals each: control, three lead tested (received lead acetate in the drinking water for a period of 14 d at concentrations of 250, 500 and 1000 ppm) groups. At the end of the 2 week period, malondialdehyde (MDA), nitric oxide (NO) and reduced glutathione (GSH) contents were measured to assess free radical activity in the BALF and lung tissue. Superoxide dismutase (SOD) was also determined. A significant dose-dependent increase in the BALF supernatant and lung homogenate levels of MDA and NO with decrease GSH level and SOD activity were observed in the lead-treated groups compared with the control group (p < 0.05). Thus, lead acetate may be contributed to respiratory disorders via increased oxidative stress.

Pulmonary hypertension and vascular oxidative damage in cigarette smoke exposed eNOS(-/-) mice and human smokers

CONTEXT

Cigarette smoke is known to be associated with pulmonary hypertension in humans and in animal models. Although the etiology of pulmonary hypertension in smokers is not understood, recent work has suggested a role for inducible nitric oxide synthase (iNOS) in inducing oxidative stress.

OBJECTIVE AND METHODS

To further evaluate this question, we assessed eNOS-/- mice exposed to air or cigarette smoke for the presence of pulmonary hypertension and examined vascular remodeling and expression of nitrotyrosine, a marker of reactive nitrogen species-induced oxidative damage, using immunohistochemistry. To ascertain whether oxidants may play a role in humans, we also examined lung tissue from nonsmokers, and patients with chronic obstructive pulmonary disease (COPD) with and without pulmonary hypertension.

RESULTS

We found that eNOS(-/-) mice developed increased pulmonary arterial pressure after six months cigarette smoke exposure, and this was associated with vascular remodeling and increased vascular nitrotyrosine staining. iNOS gene expression was decreased in the pulmonary arteries of the smoke exposed animals, and no protein was detectable by immunohistochemistry. In humans, vascular nitrotyrosine staining intensity was increased in smokers with COPD compared to nonsmokers, and further increased in smokers with combined COPD and pulmonary hypertension.

CONCLUSIONS

We conclude that cigarette smoke-induced pulmonary hypertension is associated with evidence of oxidative vascular damage by reactive nitrogen species, but that iNOS does not appear to be the major contributor to such damage. Most likely the source of reactive nitrogen species is the cigarette smoke itself.

Selenoprotein N deficiency in mice is associated with abnormal lung development

Mutations in the human SEPN1 gene, encoding selenoprotein N (SepN), cause SEPN1-related myopathy (SEPN1-RM) characterized by muscle weakness, spinal rigidity, and respiratory insufficiency. As with other members of the selenoprotein family, selenoprotein N incorporates selenium in the form of selenocysteine (Sec). Most selenoproteins that have been functionally characterized are involved in oxidation-reduction (redox) reactions, with the Sec residue located at their catalytic site. To model SEPN1-RM, we generated a Sepn1-knockout (Sepn1(-/-)) mouse line. Homozygous Sepn1(-/-) mice are fertile, and their weight and lifespan are comparable to wild-type (WT) animals. Under baseline conditions, the muscle histology of Sepn1(-/-) mice remains normal, but subtle core lesions could be detected in skeletal muscle after inducing oxidative stress. Ryanodine receptor (RyR) calcium release channels showed lower sensitivity to caffeine in SepN deficient myofibers, suggesting a possible role of SepN in RyR regulation. SepN deficiency also leads to abnormal lung development characterized by enlarged alveoli, which is associated with decreased tissue elastance and increased quasi-static compliance of Sepn1(-/-) lungs. This finding raises the possibility that the respiratory syndrome observed in patients with SEPN1 mutations may have a primary pulmonary component in addition to the weakness of respiratory muscles.

The effect of a single dose of acetaminophen on airways response in children with asthma

Accumulating evidence suggests that the use of acetaminophen increases the risk of developing asthma and that its widespread use has contributed to the increasing prevalence of asthma.

STUDY DESIGN

To investigate the immediate effect of a single dose of acetaminophen on airways reactivity and inflammation in asthmatic and controls. A double blind placebo-controlled study was conducted on 42 asthmatic children and 21 healthy age-matched controls. Each participant received one oral dose of acetaminophen (15 mg/kg [160 mg/mL]) and one dose of a volume-matched placebo. Physical examination, spirometry results, and fractional exhaled nitric oxide levels were assessed before and 60 minutes following acetaminophen or placebo ingestion.

RESULTS

None of the studied variables showed any significant change after acetaminophen or placebo ingestion in either the asthmatic or the control groups.

CONCLUSIONS

One single dose of acetaminophen neither evokes a bronchoconstriction response nor an increase in airway inflammation in children with asthma.

Elucidation of allosteric inhibition mechanism of 2-Cys human peroxiredoxin by molecular modeling

We used molecular dynamics (MD) simulations and protein docking to elucidate the mechanism of allosteric inhibition of the human form of peroxiredoxin (Prx), 2-Cys proliferation associated gene (PAG). Beginning by using the rat form of Prx, 2-Cys heme-binding protein as a template, we used homology modeling to find the structure of human 2-Cys PAG, which is in dimeric form. Molecular dynamics simulations showed that the structure of the reduced form of the 2-Cys PAG dimer fluctuates as the two monomers drift away and approach each other. We then used SiteMap to search for binding sites on the surface of this dimer. A binding site between the two monomers was found, and virtual screening with docking was performed to identify a ligand binding to this site. Subsequent MD simulation revealed that with this ligand in the binding site, the dimer structure of 2-Cys PAG becomes stabilized such that two cysteine residues from two monomers, which are partners of a disulfide bond of the oxidized form, remain separated. This mechanism can be used as an allosteric inhibition of Prx as a hydrogen peroxide reducer, the role of which has been studied as an anticancer drug target.

Dietary selenium fails to influence cigarette smoke-induced lung tumorigenesis in A/J mice

The goal of the study was to determine if dietary selenium inhibited the induction of lung tumorigenesis by cigarette smoke in A/J mice. Purified diets containing 0.15, 0.5, or 2.0mg/kg selenium in the form of sodium selenite were fed to female A/J mice. Half of the mice in each dietary group were exposed to cigarette smoke 6h/day, 5days/week for five months followed by a four month recovery period in ambient air, while the other half were used as controls. After the recovery period, the mice were euthanized, and their lungs were removed for further analysis. Mice exposed to smoke had a higher tumor incidence and a higher tumor multiplicity, whereas dietary Se did not affect either the tumor incidence or tumor multiplicity. An increase in dietary selenium led to increased levels of selenium in the lung as well as GPx protein levels, but dietary Se did not affect lung SOD protein levels. In conclusion, these data confirm the carcinogenic activity of cigarette smoke in mice but show that dietary Se provided as sodium selenite does not affect smoke-induced carcinogenesis in this model.

Relation of oxidant-antioxidant imbalance with disease progression in patients with asthma

CONTEXT:

Asthma is a chronic airway disorder which is associated to the inflammatory cells. Inflammatory and immune cells generate more reactive oxygen species in patients suffering from asthma which leads to tissue injury.

AIMS:

To investigate the role of oxidant-antioxidant imbalance in disease progression of asthmatic patients.

SETTINGS AND DESIGN:

In this study, 130 asthmatic patients and 70 healthy controls were documented.

METHODS:

For this malondialdehyde level, total protein carbonyls, sulfhydryls, activity of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), total blood glutathione, and total antioxidant capacity (FRAP) were measured.

STATISTICAL ANALYSIS USED:

Analysis of the data was done using unpaired student t test and one-way ANOVA analysis. P < 0.05 was considered significant.

RESULTS:

The present work showed that the systemic levels of MDA (4.19 ± 0.10 nmol/ml, P < 0.001) and protein carbonyls (1.13 ± 0.02 nmol/mg, P < 0.001) were found to be remarkably higher in asthmatic patients while protein sulfhydryls (0.55 ± 0.01 mmol/l, P < 0.05) decreased as compared to controls (2.84 ± 0.12 nmol/ml, 0.79 ± 0.02 nmol/mg and 0.60 ± 0.02 mmol/l, respectively). We also observed decrease in activities of SOD (2047 ± 50.34 U/g Hb, P < 0.05), catalase (4374 ± 67.98 U/g Hb, P < 0.01), and GPx (40.97 ± 1.05 U/g Hb, P < 0.01) in erythrocytes compared to control (2217 ± 60.11 U/g Hb, 4746 ± 89.94 U/g Hb, and 48.37 ± 2.47 U/g Hb, respectively). FRAP level (750.90 ± 21.22 μmol/l, P < 0.05) in plasma was decreased, whereas total blood glutathione increased (0.94 ± 0.02 mmol/l, P < 0.05) as seen in control (840.40 ± 28.39 μmol/l and 0.84 ± 0.04 mmol/l).

CONCLUSIONS:

This work supports and describes the hypothesis that an imbalance between oxidant-antioxidant is associated to the oxidative stress which plays a significant role in severity of the disease.

Oxidative activity of ammonium persulfate salt on mast cells and basophils: implication in hairdressers' asthma

BACKGROUND

Persulfate salts are components of bleaching powders widely used by hairdressers during hair-bleaching procedures. Hairdressers are at high risk for occupational asthma and rhinitis, and ammonium persulfate is the main etiologic agent.

OBJECTIVE

To explore the effects of ammonium persulfate on human albumin, mast cells, and basophils in order to evaluate a possible effect of ammonium persulfate oxidizing activity in the mechanism of ammonium persulfate-induced occupational asthma.

METHODS

High-performance liquid chromatography/mass spectrometry was performed on ammonium persulfate-incubated human albumin. The activation of LAD2 human mast cell and KU812 human basophil cell lines incubated with ammonium persulfate was evaluated. CD63 expression on persulfate-in-vitro-incubated blood basophils from nonexposed healthy controls (n = 31) and hairdressers with work-related respiratory symptoms (n = 29) was assessed by flow cytometry.

RESULTS

No persulfate-albumin conjugate was found. An oxidative process on tryptophan and methionine was detected. Ammonium persulfate induced reactive oxygen species (ROS) generation and the degranulation of LAD2 and KU812 cells. Human basophils from healthy controls, incubated in vitro with ammonium persulfate, showed increased CD63 expression and ROS production. In hairdressers with ammonium persulfate-caused occupational asthma (positive persulfate challenge), basophil-CD63 expression was higher than in those with a negative challenge and in healthy controls.

CONCLUSIONS

Ammonium persulfate incubated with human albumin did not generate any adduct but oxidized some amino acids. This oxidizing activity induced human mast cell and basophil activation which might be crucial in the mechanism of persulfate-induced occupational asthma and rhinitis.

Gene expression profiling following NRF2 and KEAP1 siRNA knockdown in human lung fibroblasts identifies CCL11/Eotaxin-1 as a novel NRF2 regulated gene

Background

Oxidative Stress contributes to the pathogenesis of many diseases. The NRF2/KEAP1 axis is a key transcriptional regulator of the anti-oxidant response in cells. Nrf2 knockout mice have implicated this pathway in regulating inflammatory airway diseases such as asthma and COPD. To better understand the role the NRF2 pathway has on respiratory disease we have taken a novel approach to define NRF2 dependent gene expression in a relevant lung system.

Methods

Normal human lung fibroblasts were transfected with siRNA specific for NRF2 or KEAP1. Gene expression changes were measured at 30 and 48 hours using a custom Affymetrix Gene array. Changes in Eotaxin-1 gene expression and protein secretion were further measured under various inflammatory conditions with siRNAs and pharmacological tools.

Results

An anti-correlated gene set (inversely regulated by NRF2 and KEAP1 RNAi) that reflects specific NRF2 regulated genes was identified. Gene annotations show that NRF2-mediated oxidative stress response is the most significantly regulated pathway, followed by heme metabolism, metabolism of xenobiotics by Cytochrome P450 and O-glycan biosynthesis. Unexpectedly the key eosinophil chemokine Eotaxin-1/CCL11 was found to be up-regulated when NRF2 was inhibited and down-regulated when KEAP1 was inhibited. This transcriptional regulation leads to modulation of Eotaxin-1 secretion from human lung fibroblasts under basal and inflammatory conditions, and is specific to Eotaxin-1 as NRF2 or KEAP1 knockdown had no effect on the secretion of a set of other chemokines and cytokines. Furthermore, the known NRF2 small molecule activators CDDO and Sulphoraphane can also dose dependently inhibit Eotaxin-1 release from human lung fibroblasts.

Conclusions

These data uncover a previously unknown role for NRF2 in regulating Eotaxin-1 expression and further the mechanistic understanding of this pathway in modulating inflammatory lung disease.

Changes in NADPH oxidase mRNA level can be detected in blood at inhaled corticosteroid treated asthmatic children

AIM

Oxidative stress, observed in the asthmatic airways, is not localized only to the bronchial system. It would be a great advantage to monitor the oxidative stress markers from blood especially in childhood asthma following the inflammation. Our aim was to measure the levels of antioxidants and the oxidatively damaged biomolecules. We were also interested in the gene expression alterations of the free radical source gp91(phox) subunit (CYBB) of the NADPH oxidase system, and the antioxidant heme oxygenase-1 (HMOX-1) isoenzyme in the blood. Our findings were also examined in the context of medical treatment.

MAIN METHODS

Oxidative stress parameters via photometric methods, CYBB and HMOX-1 expressions via real-time PCR were measured in 58 asthmatic and 30 healthy children.

KEY FINDINGS

Higher blood thiobarbituric acid reactive substances (TBARS) (p<0.03) and carbonylated protein (p<0.05) levels were found in the asthmatic children than in the controls. The relative expression of CYBB was significantly lower (p<0.05) in patients treated with a low daily dose of inhaled corticosteroid (ICS), than in asthmatics not receiving ICS therapy. Higher ICS doses alone or combined with long acting β2-receptor agonists did not influence the expression significantly. No similar tendency was found as regards to HMOX-1 expression.

SIGNIFICANCE

Elevated levels of damaged lipid (TBARS) and protein (carbonylated) products corroborate the presence of oxidative stress in the blood during bronchial asthma and suggest the presence of chronic oxidative overload. Our findings also suggest that ICS treatment can influence the relative CYBB mRNA expression in circulating leukocytes in a dose dependent manner.

Attenuation of acute nitrogen mustard-induced lung injury, inflammation and fibrogenesis by a nitric oxide synthase inhibitor

Nitrogen mustard (NM) is a toxic vesicant known to cause damage to the respiratory tract. Injury is associated with increased expression of inducible nitric oxide synthase (iNOS). In these studies we analyzed the effects of transient inhibition of iNOS using aminoguanidine (AG) on NM-induced pulmonary toxicity. Rats were treated intratracheally with 0.125 mg/kg NM or control. Bronchoalveolar lavage fluid (BAL) and lung tissue were collected 1 d-28 d later and lung injury, oxidative stress and fibrosis assessed. NM exposure resulted in progressive histopathological changes in the lung including multifocal lesions, perivascular and peribronchial edema, inflammatory cell accumulation, alveolar fibrin deposition, bronchiolization of alveolar septal walls, and fibrosis. This was correlated with trichrome staining and expression of proliferating cell nuclear antigen (PCNA). Expression of heme oxygenase (HO)-1 and manganese superoxide dismutase (Mn-SOD) was also increased in the lung following NM exposure, along with levels of protein and inflammatory cells in BAL, consistent with oxidative stress and alveolar-epithelial injury. Both classically activated proinflammatory (iNOS⁺ and cyclooxygenase-2⁺) and alternatively activated profibrotic (YM-1⁺ and galectin-3⁺) macrophages appeared in the lung following NM administration; this was evident within 1d, and persisted for 28 d. AG administration (50 mg/kg, 2×/day, 1d-3 d) abrogated NM-induced injury, oxidative stress and inflammation at 1d and 3d post exposure, with no effects at 7 d or 28 d. These findings indicate that nitric oxide generated via iNOS contributes to acute NM-induced lung toxicity, however, transient inhibition of iNOS is not sufficient to protect against pulmonary fibrosis.