Importance of oxidative stress in the pathogenesis and treatment of asthma

The role of selenium in inflammation and immunity: from molecular mechanisms to therapeutic opportunities

Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in some cases. In this comprehensive article, the roles of Se and individual selenoproteins in regulating immune cell signaling and function are discussed. Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells. Data obtained from cell culture and animal models are reviewed and compared with those involving human physiology and pathophysiology, including the effects of Se levels on inflammatory or immune-related diseases including anti-viral immunity, autoimmunity, sepsis, allergic asthma, and chronic inflammatory disorders. Finally, the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders are discussed.

Fat-soluble vitamins and atopic disease: what is the evidence?

The prevalence of asthma and other atopic disorders continues to increase worldwide. Examination of the epidemiologic patterns has revealed that this rise has occurred primarily in western, industrialised countries and countries transitioning to this lifestyle. While many changes have occurred in human populations over the years, it has been hypothesised that some of the relevant changes that have led to the rise in asthma and atopic disorders have been the changes from a traditional diet to a more western diet consisting of decreased intake of fruits and vegetables (sources of antioxidant vitamins and carotenoids) leading to decreased intakes of vitamins E and A, and a decrease in sun exposure (e.g. greater time spent indoors and heavy use of sunscreen) leading to decreased circulating levels of vitamin D. This review will examine the evidence for an effect of fat-soluble vitamins (vitamins A, D and K) on the development and severity of asthma and allergies. While observational studies suggest that these vitamins may play a salutary role in asthma and allergies, large, well-designed clinical trials are lacking. Of the fat-soluble vitamins, vitamin D holds great promise as an agent for primary and secondary prevention of disease. Ongoing clinical trials will help determine whether results of observational studies can be applied to the clinical setting.

Modulatory effects of low-dose hydrogen peroxide on the function of human plasmacytoid dendritic cells

Under normal conditions, plasmacytoid dendritic cells (pDCs) are located in peripheral lymphoid organs or circulate in the blood, from where they can migrate to sites of infection or inflammation. In inflamed tissues, pDCs can be exposed to elevated levels of reactive oxygen species produced by inflammatory cells and we presume that oxidative stress could affect the cellular responses of pDCs to microenvironmental stimuli. To explore this possibility, human pDCs isolated from peripheral blood of healthy donors were treated with H(2)O(2) and R837 (a Toll-like receptor 7 ligand), separately and in combination. Our results demonstrate that treatment with a low concentration (0.01 μM) of H(2)O(2) resulted in only slight changes in the expression of CD40, CD80, CD86, and CD83; however, low-dose H(2)O(2) markedly decreased the expression of HLA-DQ on pDCs. Exposure to H(2)O(2) did not trigger the release of IL-6, TNF-α, IL-8, or IFN-α from pDCs. Although addition of H(2)O(2) did not modify the capacity of pDCs to activate allogeneic IL-17- or IFN-γ-producing T cells, it significantly increased the ability of pDCs to stimulate IL-4-secreting T cells. Exposure of pDCs to H(2)O(2) before cocultivation with naïve autologous T cells significantly lowered IL-10 production by T cells, but did not affect IL-17 release. It was also observed that H(2)O(2)-exposed pDCs provided stronger stimuli for Th2 than for Th1 differentiation upon autologous activation, compared to untreated pDCs, possibly because of elevated surface expression of OX40-L. Most importantly, when pDCs were stimulated with R837 in the presence of H(2)O(2), decreased phenotypic activation, decreased chemokine and cytokine release, and impaired allo- and autostimulatory functions of pDCs were detected, indicating that pDCs exposed to oxidative stress in vivo may have an anti-inflammatory or tolerogenic role in regulating adaptive immune responses.

Pathogenesis and disease mechanisms of occupational asthma

Occupational asthma (OA) is one of the most common forms of work-related lung disease in all industrialized nations. The clinical management of patients with OA depends on an understanding of the multifactorial pathogenetic mechanisms that can contribute to this disease. This article discusses the various immunologic and nonimmunologic mechanisms and genetic susceptibility factors that drive the inflammatory processes of OA.

Role of thioredoxin in lung disease

Thioredoxin system is a ubiquitous thiol oxidoreductase system that regulates cellular reduction/oxidation (redox) status. It includes thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Trx plays an essential role in cell function by limiting oxidative stress directly via antioxidant effects and indirectly by proteins interaction with key signal transduction molecules. A variety of signaling molecules have been implicated in the cytoprotection conferred by Trx, such as autophagic proteins, p38 mitogen-activated protein kinase, nuclear factor-κB, phosphatidylinositol 3-kinase. Recent studies indicated that Trx may contribute to the pathogenesis of COPD, asthma and lung injury. Enhanced Trx expression or application of recombinant Trx afforded protection in preclinical models of pulmonary tissue injury, which suggested Trx may be used in future therapeutic applications. The focus of this review is on the significance of Trx in various pulmonary diseases, which as a potential therapeutic strategy to protect against oxidative stress and inflammation.

Hyperoxidized peroxiredoxins in peripheral blood mononuclear cells of asthma patients is associated with asthma severity

AIMS

Oxidative stress is involved in the pathogenesis of asthma, and peroxiredoxins (PRDX) may be critical in controlling intracellular oxidative stress. The aim of this study was to evaluate expressions of PRDX and their hyperoxidized forms in asthmatic individuals.

MAIN METHODS

The levels of expression of PRDX1, PRDX2, PRDX3, and PRDX6 and their hyperoxidized forms (PRDX-SO(3)) were measured in PBMCs from asthma patients and control subjects. In addition, cells from these subjects were treated with hydrogen peroxide (H(2)O(2)) and their intracellular concentrations of reactive oxygen species (ROS) were measured.

KEY FINDINGS

The ratios of hyperoxidized to total PRDX (PRDX-SO(3/)PRDX) in PBMCs were significantly higher in asthma patients than in normal subjects and were correlated with disease severity, with the highest ratio seen in patients with severe asthma. Furthermore, H(2)O(2) treatment of PBMCs, particularly lymphocytes, increased intracellular ROS concentrations with greater and more persistent increases observed in cells from asthmatic than from control subjects.

SIGNIFICANCE

Hyperoxidation of PRDX may serve as a biomarker of asthma severity and may predict enhanced susceptibility to oxidative stress load in PBMCs of asthmatics.

Pediatric asthma: natural history, assessment, and treatment

Wheezing and childhood asthma are not synonymous but rather comprise a heterogeneous group of conditions that have different outcomes over the course of childhood. Most infants who wheeze have a transient condition associated with diminished airway function at birth and have no increased risk of asthma later in life. However, children with persistent wheezing throughout childhood and frequent exacerbations represent the main challenge today. Studying the natural history of asthma is important for the understanding and accurate prediction of the clinical course of different phenotypes. To date, a great improvement has been achieved in reducing the frequency of asthma symptoms. However, neither decreased environmental exposure nor controller treatment, as recommended by the recent National Asthma Education And Prevention Program, can halt the progression of asthma in childhood or the development of persistent wheezing phenotype. This review focuses on the recent studies that led to the current understanding of asthma phenotypes in childhood and the recommended treatments.

Effects of physical exercise on lung injury and oxidant stress in children with asthma

BACKGROUND

The aim of this study was to investigate the influence of exercise training on oxidative stress and markers of lung inflammation in children with asthma.

METHODS

Thirty children aged 8-13 years diagnosed with asthma were enrolled in the study as well as 13 healthy children. One group received only pharmacological treatment and the other group was also enrolled in an exercise programme. Venous blood and 24-hour urine samples were obtained from the children enrolled in the study at the beginning and end of the study. Leukotriene E4 and creatinine levels were measured in the urine and matrix metallopeptidase (MMP-9), endothelin-1(ET-1), malnodialdehyde (MDA), IgE and specific IgE levels were measured in blood samples.

RESULTS

Leukotriene E4, MDA and MMP9 levels decreased significantly with treatment in both groups (p < 0.001). However, ET-1 levels decreased significant only in the exercise group (26.5 ± 3.6 vs 21.3 ± 2.4 pg/ml respectively, p = 0.001). Moreover, ET-1 levels were found to be significantly lower in the exercise group compared to the only pharmacotherapy group (24.2 ± 3.1 vs 21.3 ± 2.4 pg/ml, p=0.007).

CONCLUSIONS

Positive influences of exercise training in children with asthma may be mediated by decrease in ET-1 levels.

Unbalanced oxidant-antioxidant status and its effects in pediatric diseases

Oxidative stress results from a disparity between the generation of reactive oxygen species and the antioxidant ability of the organism. The alteration of the oxidant-antioxidant system brings in adults an effective state of imbalance, which may influence the pathogenesis of many diseases. Oxidative stress also plays a pivotal role in the progression of various pathologies in childhood, through a manipulation of regulatory proteins. In fact, several studies have demonstrated that an unbalanced oxidant-antioxidant status is able to determine toxic effects even during infancy. Therefore, the aim of this review was to summarize current knowledge about the dynamic relationship between oxidative stress and systemic diseases during childhood. In order to better understand these complex mechanisms, a comprehensive review of the literature was done, focusing mainly on pre-pubertal children. In fact, this age-group offers a unique opportunity to exclude confounding factors, especially those related to the metabolic effects induced by puberty. Early identification of these very young patients should be aimed at minimizing the degree of oxidative damage. Only by achieving early diagnosis, will it be possible to identify those children who could benefit from specific therapeutic approaches targeting oxidative stress.

Interaction and localization of synthetic nanoparticles in healthy and cystic fibrosis airway epithelial cells: effect of ozone exposure

BACKGROUND

Nanoparticles (NPs) produced by nanotechnology processes have taken the field of medicine by storm. Concerns about safety of these NPs in humans, however, have recently been raised. Although studies of NP toxicity have focused on lung disease the mechanistic link between NP exposure and lung injury remained unclear. This is primarily due to a lack of availability of appropriate airway disease models and sophisticated microscopic techniques to study nano-sized particulate delivery and resulting responses.

METHODS

Air-liquid interface (ALI) cultures of non-cystic fibrosis (CF) and CF airway epithelial cells were exposed to the FITC-labeled NPs using a PennCentury microsprayer™. Uptake of NPs was assessed by FACS. Laser scanning microscopy (LSM) was performed and the images were analyzed by an advanced imaging software to study particle deposition and uptake.

RESULTS

Flow cytometry data revealed that CF cells accumulated increased amounts of NPs. The increased NP uptake could be attributed to the reduced CF transmembrane conductance regulator (CFTR) function as a similar increased retention/uptake was observed in cells whose CFTR expression was downregulated by antisense oligonucleotide. NPs alone did not induce pro-inflammatory cytokine release or cell death. The cell culture system was sensitive to ozone but exposure to the uncoated synthetic NPs used in this study, did not cause any synergistic or suppressive effects. LSM imaging and subsequent image restoration further indicated particle uptake and intracellular localization. Exposure to ozone increased nuclear uptake in both non-CF and CF cells.

CONCLUSION

Our findings demonstrate the uptake of NPs using ALI cultures of non-CF and CF airway epithelial cells. The NPs used here were useful in demonstrating uptake by airway epithelial cells without causing adverse effects in presence or absence of ozone. However, to totally exclude toxic effects, chronic studies under in vivo conditions using coated particulates are required.

Selenium and asthma

Se is a potent nutritional antioxidant important for various aspects of human health. Because asthma has been demonstrated to involve increased oxidative stress, levels of Se intake have been hypothesized to play an important role in the pathogenesis of asthma. However, significant associations between Se status and prevalence or severity of asthma have not been consistently demonstrated in human studies. This highlights both the complex etiology of human asthma and the inherent problems with correlative nutritional studies. In this review, the different findings in human studies are discussed along with results from limited intervention studies. Mouse models of asthma have provided more definitive results suggesting that the benefits of Se supplementation may depend on an individual's initial Se status. This likely involves T helper cell differentiation and the mechanistic studies that have provided important insight into the effects of Se levels on immune cell function are summarized. Importantly, the benefits and adverse effects of Se supplementation must both be considered in using this nutritional supplement for treating asthma. With this in mind new approaches are discussed that may provide more safe and effective means for using Se supplementation for asthma or other disorders involving inflammation or immunity.

Transforming growth factor-β and nuclear factor E2–related factor 2 regulate antioxidant responses in airway smooth muscle cells: role in asthma

RATIONALE

Aberrant airway smooth muscle cell (ASMC) function and overexpression of transforming growth factor (TGF)-β, which modulates ASMC proliferative and inflammatory function and induces oxidant release, are features of asthma. Nuclear factor E2-related factor 2 (Nrf2) activates antioxidant genes conferring protection against oxidative stress.

OBJECTIVES

To determine the role of Nrf2 in ASMCs and its modulation by TGF-β, and compare Nrf2 activity in ASMCs from subjects with severe and nonsevere asthma and healthy subjects.

METHODS

ASMCs were cultured from airways of subjects without asthma, and from airway biopsies from patients with severe and nonsevere asthma. We studied Nrf2 activation on antioxidant gene expression and proliferation, the effect of TGF-β on Nrf2 transcriptional activity, and the impact of Nrf2 activation on TGF-β–mediated proliferation and IL-6 release. Nrf2–antioxidant response elements binding and Nrf2-dependent antioxidant gene expression was determined in asthmatic ASMCs.

MEASUREMENTS AND MAIN RESULTS

Activation of Nrf2 led to up-regulation of the antioxidant genes heme oxygenase (HO)-1, NAD(P)H:quinone oxidoreductase, and manganese superoxide dismutase, and a reduction in proliferation. TGF-β reduced Nrf2-mediated antioxidant gene transcription through induction of activating transcription factor-3 expression. Nrf2 activation attenuated TGF-β–mediated reduction in HO-1,ASMC proliferation, and IL-6 release. Nrf2–antioxidant response elements binding was reduced in ASMCs from patients with severe asthma compared with ASMCs from patients with nonsevere asthma and normal subjects. HO-1 expression was reduced in ASMCs from patients with both nonsevere and severe asthma compared with healthy subjects.

CONCLUSIONS

Nrf2 regulates antioxidant responses and proliferation in ASMCs and is inactivated by TGF-β. Nrf2 reduction may underlie compromised antioxidant protection and aberrant ASM function in asthma.

Oxidative stress in asthma

Asthma is a chronic inflammatory lung disease that results in airflow limitation, hyperreactivity, and airway remodeling. There is strong evidence that an imbalance between the reducing and oxidizing systems favoring a more oxidative state is present in asthma. Endogenous and exogenous reactive oxygen species, such as superoxide anion, hydroxyl radical, hypohalite radical, and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide, peroxynitrite, and nitrite, play a major role in the airway inflammation and are determinants of asthma severity. Asthma is also associated with decreased antioxidant defenses, such as superoxide dismutase, catalase, and glutathione. In this review, we will summarize the current knowledge and discuss the current and future strategies for the modulation of oxidative stress in asthma.

Vitamin E prevents NRF2 suppression by allergens in asthmatic alveolar macrophages in vivo

Asthma is a chronic inflammatory airway disease associated with increased generation of reactive oxidant species and disturbed antioxidant defenses. NRF2 is the master transcription factor that regulates the expression of Phase II antioxidant and detoxifying enzymes. Disruption of NRF2 augments oxidative stress and inflammation in a mouse model of asthma, suggesting a protective role for NRF2 in the lungs in vivo. Yet, little is known about the regulation and function of NRF2 in human asthmatics. Using segmental allergen challenge, a well-established experimental model of IgE-mediated asthma exacerbation in human atopic asthmatics, we investigated the effects of a specific allergen and the modulatory role of vitamin E on NRF2 and a NRF2-target gene, superoxide dismutase, in alveolar macrophages recovered from the airways at 24h after allergen instillation in vivo. Allergen-provoked airway inflammation in sensitive asthmatics caused a profound inhibition of macrophage NRF2 activity and superoxide dismutase, rendering them incapable of responding to the NRF2 inducers. Prolonged treatment with high doses of the antioxidant vitamin E lessened this allergen-induced drop in alveolar macrophage NRF2. These results are the first to demonstrate that NRF2 expression in human asthmatics is compromised upon allergen challenge but can be rescued by vitamin E in vivo.

The indoor environment and its effects on childhood asthma

PURPOSE OF REVIEW

Indoor pollutants and allergens cause asthma symptoms and exacerbations and influence the risk of developing asthma. We review recent studies regarding the effects of the indoor environment on childhood asthma.

RECENT FINDINGS

Exposure to some indoor allergens and second hand smoke are causally related to the development of asthma in children. Many recent studies have demonstrated an association between exposure to indoor pollutants and allergens and airways inflammation, asthma symptoms, and increased healthcare utilization among individuals with established asthma. Genetic polymorphisms conferring susceptibility to some indoor exposures have also been identified, and recent findings support the notion that environmental exposures may influence gene expression through epigenetic modification. Recent studies also support the efficacy of multifaceted environmental interventions in childhood asthma.

SUMMARY

Studies have provided significant evidence of the association between many indoor pollutants and allergens and asthma morbidity, and have also demonstrated the efficacy of multifaceted indoor environmental interventions in childhood asthma. There is also a growing body of evidence suggesting that some indoor pollutants and allergens may increase the risk of developing asthma. Future studies should examine mechanisms whereby environmental exposures may influence asthma pathogenesis and expand the current knowledge of susceptibility factors for indoor exposures.

Pulmonary biocompatibility assessment of inhaled single-wall and multiwall carbon nanotubes in BALB/c mice

With the widespread application of carbon nanotubes (CNTs) in diverse commercial processes, scientists are now concerned about the potential health risk of occupational exposures. In this study, CNT-induced pulmonary toxicity was investigated by exposing BALB/c mice to aerosolized single-wall (SW) CNT and multiwall (MW) CNT (5 μg/g of mice) for 7 consecutive days in a nose-only exposure system. Microscopic studies showed that inhaled CNTs were homogeneously distributed in the mouse lung. The total number of bronchoalveolar lavage polymorphonuclear leukocytes recovered from the mice exposed to SWCNT and MWCNT (1.2 × 10(6) ± 0.52 and 9.87 × 10(5) ± 1.45; respectively) was significantly greater than control mice (5.46 × 10(5) ± 0.78). Rapid development of pulmonary fibrosis in mice that inhaled CNT was also confirmed by significant increases in the collagen level. The lactate dehydrogenase levels were increased nearly 2- and 2.4-fold in mice that inhaled SWCNT and MWCNT, respectively, as compared with control mice. In addition, exposure of CNTs to mice showed a significant (p < 0.05) reduction of antioxidants (glutathione, superoxide dismutase, and catalase) and induction of oxidants (myloperoxidase, oxidative stress, and lipid peroxidation) compared with control. Apoptosis-related proteins such as caspase-3 and -8 activities were also significantly increased in mice that inhaled CNT than in control mice. Together, this study shows that inhaled CNTs induce inflammation, fibrosis, alteration of oxidant and antioxidant levels, and induction of apoptosis-related proteins in the lung tissues to trigger cell death.

Micronutrient levels in children exposed to secondhand tobacco smoke

INTRODUCTION

Antioxidant micronutrients are the body's primary defense against the oxidative stress of secondhand smoke (SHS). Micronutrient levels have been associated with lung function; decreased levels of vitamin C and β-carotene have been associated with SHS exposure in children. We sought to determine the association between SHS exposure and micronutrient levels in children.

METHODS

Data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES) were analyzed. Serum cotinine levels were categorized into no (<0.015 ng/mL), moderate (0.015 to <2.0 ng/mL), and high (2.0-15.0 ng/mL) smoke exposure; t-tests determined associations between exposure and levels of micronutrients. Significant bivariate associations were tested further using linear regression.

RESULTS

In all, 2,218 children, aged 6-18 years, were included (response rate of 82%); 17% had no, 76% moderate, and 7% high exposure. Children with no exposure had higher levels of vitamin A, C, and E, cis- and trans-β-carotene, and folate, while levels of vitamins B(6), B(12), and D did not differ. In regression analysis, higher cotinine levels were negatively associated with levels of vitamin C (β = -.03; p < .01), cis-β-carotene (β = -.04; p < .01), trans-β-carotene (β = -.7; p < .01), folate (β = -.5; p < .001) and vitamin A (β = -.6; p < .01).

CONCLUSIONS

Children exposed to SHS have lower levels of antioxidants controlling for dietary and supplement intake. This antioxidant depletion may increase systemic inflammation and sensitivity to other oxidant stresses. Parents should be counseled on these specific risks from SHS exposure for their children, and the importance of smoking cessation and eliminating children's exposure to tobacco smoke.

Epithelial, dendritic, and CD4(+) T cell regulation of and by reactive oxygen and nitrogen species in allergic sensitization

BACKGROUND

While many of the contributing cell types and mediators of allergic asthma are known, less well understood are the factors that induce allergy in the first place. Amongst the mediators speculated to affect initial allergen sensitization and the development of pathogenic allergic responses to innocuous inhaled antigens and allergens are exogenously or endogenously generated reactive oxygen species (ROS) and reactive nitrogen species (RNS).

SCOPE OF REVIEW

The interactions between ROS/RNS, dendritic cells (DCs), and CD4(+) T cells, as well as their modulation by lung epithelium, are of critical importance for the genesis of allergies that later manifest in allergic asthma. Therefore, this review will primarily focus on the initiation of pulmonary allergies and the role that ROS/RNS may play in the steps therein, using examples from our own work on the roles of NO(2) exposure and airway epithelial NF-κB activation.

MAJOR CONCLUSIONS

Endogenously generated ROS/RNS and those encountered from environmental sources interact with epithelium, DCs, and CD4(+) T cells to orchestrate allergic sensitization through modulation of the activities of each of these cell types, which quantitiatively and qualitatively dictate the degree and type of the allergic asthma phenotype.

GENERAL SIGNIFICANCE

Knowledge of the effects of ROS/RNS at the molecular and cellular levels has the potential to provide powerful insight into the balance between inhalational tolerance (the typical immunologic response to an innocuous inhaled antigen) and allergy, as well as to potentially provide mechanistic targets for the prevention and treatment of asthma.

Does adherence to the Mediterranean diet have a protective effect against active and passive smoking?

OBJECTIVE

To investigate the existing evidence about whether adherence to the Mediterranean diet may have a role as an effect modifier of active and passive smoking on human health.

STUDY DESIGN

Review.

METHODS

An overview of emerging evidence and published studies that cover the interaction between the Mediterranean diet and smoking.

RESULTS

Both epidemiological and laboratory studies have shown that the Mediterranean diet has a protective effect against biochemical and molecular processes that lead to cancer, cardiovascular disease and respiratory illness. Based on the high daily intake of vitamins and antioxidants, the Mediterranean diet is comprised of a number of compounds that could alter certain outcomes related to smoking. Studies have indicated that certain diseases attributable to smoking, such as lung cancer, asthma and cardiovascular disease, are inversely associated with certain antioxidants and lipids.

CONCLUSIONS

The literature indicates that the existence of a partial interaction between adherence to the Mediterranean diet and the health effects of smoking is possible. Further research is needed to lead to a conclusive statement on this hypothesis.

Leukocyte nicotinamide adenine dinucleotide phosphate-reduced oxidase is required for isocyanate-induced lung inflammation

BACKGROUND

Isocyanates are low-molecular-weight compounds noted for inducing occupational and environmental asthma. Isocyanate-induced lung disease, an oxidant stress-dependent pulmonary inflammation, is the leading cause of occupational asthma.

OBJECTIVES

To address the role of leukocyte-produced oxidants in airway inflammation induced by toluene diisocyanate (TDI), and to elucidate the role of leukocyte nicotinamide adenine dinucleotide phosphate-reduced (NADPH) oxidase in pathogenesis by TDI.

METHODS

Wild-type mice and NADPH oxidase-deficient mice (neutrophil cytosolic factor 1 mutant, Ncf1(-/-)) were intranasally injected, challenged with inhalatory TDI, and then investigated for lung inflammation.

RESULTS

Cell infiltration in lung tissue and leukocytes in bronchoalveolar lavage, airway reactivity to a methacholine challenge, and TDI-induced inflammatory cytokine expression and nuclear factor activation in the lung tissue were all markedly lower in Ncf1(-/-) mice. Wild-type mice treated with blocking antibodies against CD4 and IL-17 showed markedly lower TDI-induced airway hyperresponsiveness.

CONCLUSION

Leukocyte NADPH oxidase is an essential regulator in TDI-induced airway inflammation through redox modification of immune responses.

D-4F, an apoA-1 mimetic, decreases airway hyperresponsiveness, inflammation, and oxidative stress in a murine model of asthma

Asthma is characterized by oxidative stress and inflammation of the airways. Although proinflammatory lipids are involved in asthma, therapies targeting them remain lacking. Ac-DWFKAFYDKVAEKFKEAFNH(2) (4F) is an apolipoprotein (apo)A-I mimetic that has been shown to preferentially bind oxidized lipids and improve HDL function. The objective of the present study was to determine the effects of 4F on oxidative stress, inflammation, and airway resistance in an established murine model of asthma. We show here that ovalbumin (OVA)-sensitization increased airway hyperresponsiveness, eosinophil recruitment, and collagen deposition in lungs of C57BL/6J mice by a mechanism that could be reduced by 4F. OVA sensitization induced marked increases in transforming growth factor (TGF)β-1, fibroblast specific protein (FSP)-1, anti-T15 autoantibody staining, and modest increases in 4-hydroxynonenal (4-HNE) Michael's adducts in lungs of OVA-sensitized mice. 4F decreased TGFβ-1, FSP-1, anti-T15 autoantibody, and 4-HNE adducts in the lungs of the OVA-sensitized mice. Eosinophil peroxidase (EPO) activity in bronchial alveolar lavage fluid (BALF), peripheral eosinophil counts, total IgE, and proinflammatory HDL (p-HDL) were all increased in OVA-sensitized mice. 4F decreased BALF EPO activity, eosinophil counts, total IgE, and p-HDL in these mice. These data indicate that 4F reduces pulmonary inflammation and airway resistance in an experimental murine model of asthma by decreasing oxidative stress.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Pulmonary remodeling in asthma

The inflammatory and immunologic processes responsible for asthma can produce permanently fixed obstructive lung disease unresponsive to medical therapy. This can be manifested clinically by the failure of a childhood asthmatic to reach full expected lung capacity at adulthood and by an accelerated decline in pulmonary capacity in adults. Recent studies have furthered our insight into the pathologic processes underlying these changes and the potential effects of therapy to prevent them.

The role of oxidative stress in the pathogenesis and treatment of asthma

The role of oxidative stress in asthma is gaining increasing scientific attention. The hallmark of asthma is airway inflammation. Oxidative stress may initiate and augment inflammation, and may also result from inflammation. Exposure to tobacco smoke, ozone, diesel exhaust, and a variety of other pollutants generates reactive oxygen species and other oxidative stressors. Some studies suggest that asthmatics have a decreased ability to respond to oxidative stress, while others find upregulated antioxidative function. Oxidative stress may alter the Th(1)/Th(2) immune response and result in activation of NF-kbeta, a powerful inducer of pro-inflammatory genes. Genetic polymorphisms may play an important role in determining susceptibility to oxidative stress. Many therapeutic strategies to decrease oxidative stress in asthma have been suggested. Dietary changes, antioxidant vitamins, other antioxidant drugs, Ayurvedic supplements, and even radon exposure in a hot bathroom have been studied. Minimizing exposure of young children to environmental tobacco smoke remains paramount.

Programming dendritic cells to induce T(H)2 and tolerogenic responses

A fundamental puzzle in immunology is how the immune system decides what types of immune responses to launch against different stimuli. Although much is known about control of T helper type 1 (T(H)1) and T(H)17 responses, the mechanisms that initiate T(H)2 and T regulatory (T(reg)) responses remain obscure. Emerging studies suggest a fundamental role for the innate immune system, particularly dendritic cells (DCs), in this process. We review these studies, and suggest that the innate control of T(H)2 and T(reg) responses can be viewed as different hierarchies of organization, in which DCs, their innate receptors and signaling networks, and their interactions with other cells and local microenvironments represent different levels of the hierarchy.

Novel antioxidant approaches to the treatment of upper airway inflammation

PURPOSE OF REVIEW

Current understanding of the role of oxidative stress in airway inflammation suggests that antioxidant therapy may be important to optimize the treatment. This review summarizes recent investigations of novel antioxidant agents for upper airway inflammation, with selected studies focused on lower airway disease as additional candidate therapeutics.

RECENT FINDINGS

Recently investigated antioxidant therapies for airway inflammation may be broadly grouped into three categories: endogenous metabolic agents, vitamins/nutrients, and botanical extracts. Studies examining effects in upper airway inflammation are limited and primarily consist of in-vitro human and in-vivo animal models. More extensive studies have investigated the benefits of antioxidants in lower airway conditions such as allergic asthma. Existing evidence identifies antioxidant agents with potential therapeutic value, although human studies suggest that subpopulations affected by specific genetic, environmental, dietary factors, or all are most likely to benefit from antioxidant therapy.

SUMMARY

Oxidative stress plays a causative role in upper airway inflammation, and novel strategies to mitigate cellular injury with antioxidant therapy may ameliorate disease in target populations. Preclinical studies demonstrate evidence of anti-inflammatory effects for a number of promising antioxidant agents. Well designed interventional human studies of the upper airway, which account for complex gene-environment-diet interactions, will be necessary to adequately examine the potential clinical benefit of antioxidant therapies for rhinosinusitis.

The T helper type 2 response to cysteine proteases requires dendritic cell-basophil cooperation via ROS-mediated signaling

The mechanisms that initiate T helper type 2 (T(H)2) responses are poorly understood. Here we demonstrate that cysteine protease-induced T(H)2 responses occur via 'cooperation' between migratory dermal dendritic cells (DCs) and basophils positive for interleukin 4 (IL-4). Subcutaneous immunization with papain plus antigen induced reactive oxygen species (ROS) in lymph node DCs and in dermal DCs and epithelial cells of the skin. ROS orchestrated T(H)2 responses by inducing oxidized lipids that triggered the induction of thymic stromal lymphopoietin (TSLP) by epithelial cells mediated by Toll-like receptor 4 (TLR4) and the adaptor protein TRIF; by suppressing production of the T(H)1-inducing molecules IL-12 and CD70 in lymph node DCs; and by inducing the DC-derived chemokine CCL7, which mediated recruitment of IL-4(+) basophils to the lymph node. Thus, the T(H)2 response to cysteine proteases requires DC-basophil cooperation via ROS-mediated signaling.

The role of oxidative stress in the pathogenesis of asthma

Oxidative stress plays a critical role in the pathogenesis of asthma. To effectively control oxidative stress in asthmatics, it is important to investigate the precise intracellular mechanism by which the development of immunity, rather than immune tolerance and progression of airway inflammation, is induced. In this article, we suggest that protein tyrosine phosphatases, as intracellular negative regulators, and intracellular antioxidant enzymes such as peroxiredoxins can be regulated by oxidative stress during intracellular signaling.

A novel dithiol amide CB3 attenuates allergic airway disease through negative regulation of p38 mitogen-activated protein kinase

RATIONALE

Cellular redox homeostasis altered by excessive production of reactive oxygen species (ROS) and weakening of the antioxidant defense leads to oxidative stress. Oxidative stress is characterized as a decrease in glutathione/glutathione disulfide (GSH/GSSG) and the triggering of a number of the redox-sensitive signaling cascades. Recent studies have demonstrated that ROS play an important role in the pathogenesis of airway inflammation and hyperresponsiveness.

OBJECTIVES

Here we characterized for the first time the protective properties of a new hydrophobic thiol compound, N-acetyl cysteine proline cysteine amide (CB3), in allergic airway diseases.

METHODS

We used ovalbumin (OVA)-inhaled mice to evaluate the role of CB3 as an antiinflammatory reagent and to determine its molecular signaling activity in allergic airways.

MEASUREMENTS AND MAIN RESULTS

The administration of CB3 (1-50 mg/kg) to OVA-inhaled mice restored the decreased GSH levels, enhanced IL-10 expression, and significantly reduced the increase of Th2 cytokines and OVA-specific IgE. CB3 decreased the number of inflammatory cells and airway hyperresponsiveness in the lungs. We also found that the administration of CB3 dramatically decreased the nuclear translocation of the nuclear factor-κB (NF-κB) and the phosphorylation of p38 mitogen-activated protein kinases (MAPKs) in lungs after OVA inhalation. In addition, allergen-induced airway inflammation and hyperresponsiveness were substantially reduced by the administration of inhibitors of NF-κB and p38 MAPK, BAY 11-7085, and SB 239063, respectively.

CONCLUSIONS

These results suggest that CB3 attenuates allergic airway disease by up-regulation of GSH levels as well as inhibition of NF-κB and p38 MAPK activity.

Thioredoxin suppresses airway inflammation independently of systemic Th1/Th2 immune modulation

Oxidative stress plays an important role in the pathogenesis of asthma via the upregulation of local inflammatory mediators and/or promoting Th2-skewing during Ag sensitization. Thioredoxin (TRX), a 12 kDa redox-active protein with antioxidative property, has been recently shown to play a protective role in various inflammatory diseases. Using a mouse model of asthma, we show here that IL-13 and eotaxin production are decreased in TRX-Tg mice leading to reduced eosinophils recruitment and mucus metaplasia. The reduction in airway inflammation occurs without the attenuation of systemic Th2 immunity in that comparable levels of Th2-type cytokines and Ig were detected in LN and serum, respectively, from TRX-Tg and WT mice. Likewise, CD4(+) T cells from both strains of mice developed similar Th1 and Th2 responses in vitro. Asthmatic lungs of TRX-Tg and WT mice contained similar amounts of GATA-3(+) and Foxp3(+) T cells. Finally, production of MIF, an upstream modulator of airway inflammation, was significantly reduced in the lungs of TRX-Tg mice. Our data suggest that TRX suppresses airway inflammation by inhibiting MIF production thereby limiting the downstream recruitment of eosinophils to the lung independently of modulating systemic Th1/Th2 immunity.

Nrf2 protects against pulmonary fibrosis by regulating the lung oxidant level and Th1/Th2 balance

Background

Pulmonary fibrosis is a progressive and lethal disorder. Although the precise mechanisms of pulmonary fibrosis are not fully understood, oxidant/antioxidant and Th1/Th2 balances may play an important role in many of the processes of inflammation and fibrosis. The transcription factor Nrf2 acts as a critical regulator for various inflammatory and immune responses by controlling oxidative stress. We therefore investigated the protective role of Nrf2 against the development of pulmonary fibrosis.

Methods

To generate pulmonary fibrosis, both wild-type C57BL/6 mice and Nrf2-deficient mice of the same background were administered bleomycin intratracheally.

Results

The survival of Nrf2-deficient mice after bleomycin administration was significantly lower than that of wild-type mice. The degree of bleomycin-induced initial pulmonary inflammation and pulmonary fibrosis was much more severe in Nrf2-deficient mice than in wild-type mice. The expression of antioxidant enzymes and phase II detoxifying enzymes was significantly reduced in the lungs of Nrf2-deficient mice, concomitant with an elevation of lung 8-isoprostane level, compared with wild-type mice. The expression of Th2 cytokines, such as interleukin-4 and interleukin-13, was significantly elevated in the lungs of Nrf2-deficient mice with an increase in the number of Th2 cells that express GATA-binding protein 3.

Conclusions

The results indicated that Nrf2 protects against the development of pulmonary fibrosis by regulating the cellular redox level and lung Th1/Th2 balance. Thus, Nrf2 might be an important genetic factor in the determination of susceptibility to pulmonary fibrosis.

Toluene diisocyanate (TDI) regulates haem oxygenase-1/ferritin expression: implications for toluene diisocyanate-induced asthma

Diisocyanate is a leading cause of occupational asthma (OA). Diisocyanate-induced OA is an inflammatory disease of the airways that is associated with airway remodelling. Although the pathogenic mechanisms are unclear, oxidative stress may be related to the pathogenesis of diisocyanate-induced OA. In our previous report, we observed that the expression of ferritin light chain (FTL) was decreased in both of bronchoalveolar lavage fluid and serum of patients with diphenyl-methane diisocyanate (MDI)-induced OA compared to those of asymptomatic exposed controls and unexposed healthy controls. In this study of toluene diisocyanate (TDI)-OA, we found identical findings with increased transferrin and decreased ferritin levels in the serum of patients with TDI-OA. To elucidate whether diisocyanate suppresses FTL synthesis directly, we tested the effect of TDI on the FTL synthesis in A549 cells, a human airway epithelial cell line. We found that haem oxygenase-1 as well as FTL was suppressed by treatment with TDI in dose- and time-dependent manners. We also found that the synthesis of other anti-oxidant proteins such as thioredoxin-1, glutathione peroxidase, peroxiredoxin 1 and catalase were suppressed by TDI. Furthermore, TDI suppressed nuclear translocation of Nrf2 through suppressing the phosphorylation of mitogen-activated protein kinases (MAPKs); extracellular-regulated kinase 1/2 (ERK1/2); p38; and c-Jun N-terminal kinase (JNK). Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists, 15-deoxy-Delta(12,14)-PGJ2 and rosiglitazone rescued the effect of TDI on HO-1/FTL expression. Collectively, our findings suggest that TDI suppressed HO-1/FTL expression through the MAPK-Nrf2 signalling pathway, which may be involved in the pathogenesis of TDI-induced OA. Therefore, elucidating these observations further should help to develop the therapeutic strategies of diisocyanate-induced OA.

Pollen-induced oxidative stress influences both innate and adaptive immune responses via altering dendritic cell functions

It has been demonstrated that pollen grains contain NAD(P)H oxidases that induce oxidative stress in the airways, and this oxidative insult is critical for the development of allergic inflammation in sensitized mice. On the basis of this observation, we have examined whether pollen grain exposure triggers oxidative stress in dendritic cells (DCs), altering their functions. To test this hypothesis, human monocyte-derived DCs were treated with ragweed pollen grains. Our findings show that exposure to pollen grains induces an increase in the intracellular levels of reactive oxygen species in DCs. Our data also indicate that besides the NAD(P)H oxidases, other component(s) of pollen grains contributes to this phenomenon. Elevated levels of intracellular reactive oxygen species triggered the production of IL-8 as well as proinflammatory cytokines, such as TNF-alpha and IL-6. Treatment with pollen grains initiated the maturation of DCs, strongly upregulated the membrane expression of CD80, CD86, CD83, and HLA-DR, and caused only a slight increase in the expression of CD40. The pollen-treated DCs induced the development of naive T lymphocytes toward effector T cells with a mixed profile of cytokine production. Antioxidant inhibited both the phenotypic and functional changes of DCs, underlining the importance of oxidative stress in these processes. Collectively, these data show that pollen exposure-induced oxidative stress may contribute to local innate immunity and participate in the initiation of adaptive immune responses to pollen Ags.

Endogenous antioxidants and radical scavengers

All living organisms are constantly exposed to oxidant agents deriving from both endogenous and exogenous sources capable to modify biomolecules and induce damages. Free radicals generated by oxidative stress exert an important role in the development of tissue damage and aging. Reactive species (RS) derived from oxygen (ROS) and nitrogen (RNS) pertain to free radicals family and are constituted by various forms of activated oxygen or nitrogen. RS are continuosly produced during normal physiological events but can be removed by antioxidant defence mechanism: the imbalance between RS and antioxidant defence mechanism leads to modifications in cellular membrane or intracellular molecules. In this chapter only endogenous antioxidant molecules will be critically discussed, such as Glutathione, Alpha-lipoic acid, Coenzyme Q, Ferritin, Uric acid, Bilirubin, Metallothioneine, L-carnitine and Melatonin.

Use of multivitamin supplements in relation to allergic disease in 8-y-old children

BACKGROUND

Multivitamins are frequently consumed by children, but it is unclear whether this affects the risk of allergic disease.

OBJECTIVE

We sought to study the association between multivitamin supplementation and allergic disease in 8-y-old children.

DESIGN

Data were obtained from a Swedish birth cohort study. Information on lifestyle factors, including use of vitamin supplements, environmental exposures, and symptoms and diagnoses of allergic diseases, was obtained by parental questionnaires. In addition, allergen-specific IgE concentrations of food and airborne allergens were measured in blood samples collected at age 8 y. A total of 2423 children were included in the study. The association between use of vitamin supplements and the selected health outcomes was analyzed with logistic regression.

RESULTS

Overall, no strong and consistent associations were observed between current multivitamin use and asthma, allergic rhinitis, eczema, or atopic sensitization at age 8 y. However, children who reported that they started taking multivitamins before or at age 4 y had a decreased risk of sensitization to food allergens (odds ratio: 0.61; 95% CI: 0.39, 0.97) and tendencies toward inverse associations with allergic rhinitis. In contrast, there was no consistent association among children who started to use multivitamins at or after age 5 y.

CONCLUSION

Our results show no association between current use of multivitamins and risk of allergic disease but suggest that supplementation with multivitamins during the first years of life may reduce the risk of allergic disease at school age.

Cough: The Emerging Role of the TRPA1 Channel

Sneezing, cough, mucus secretion, and bronchoconstriction represent the main components of a coordinated and efficient reaction direct to expel or neutralize irritant agents from the respiratory system. A dense network of sensory nerves localized from the nose to the lower airways beneath the epithelium subserves this function. A variety of receptors and channels present in sensory nerve terminals by sensing irritant stimuli activate the system in emergence and initiate protective reflex responses, including cough. Previous and recent literature highlights the prominent role of some transient receptor potential (TRP) ion channels, and specifically the vanilloid 1 (TRPV1) and the ankyrin 1 (TRPA1) as sensors of airway irritation and initiators of the cough reflex.

Increased oxidative stress in the airway and development of allergic inflammation in a mouse model of asthma

BACKGROUND

The exact pathogenic role of oxidative stress in the development of allergic airway inflammation is still largely unknown.

OBJECTIVE

To investigate a possible link between increased pulmonary oxidative stress and the pivotal features of asthma during the mounting of an allergic inflammatory response.

METHODS

To determine the relationship between oxidative stress and allergic inflammatory responses, we evaluated the sequential kinetics of oxidative stress in the lung, the development of airway inflammation, mucin hypersecretion, and airway hyperresponsiveness (AHR) in an ovalbumin (OVA)-sensitized and challenged mouse with and without antioxidant. Parameters were measured at 9 points for more than 28 days, starting from the first day of OVA challenge with or without antioxidant treatment. The ratio of reduced to oxidized glutathione in the lungs and levels of intracellular reactive oxygen species (ROS) in the bronchial epithelium were serially measured. Bronchoalveolar lavage fluid cells, histopathologic features, and AHR were analyzed at the same time points.

RESULTS

The reduced to oxidized glutathione ratio was reduced from immediately after OVA challenge to day 1, remained at this level until day 1, and rapidly recovered to the normal level after more than 2 days. Intracellular ROS levels in the bronchial epithelium followed similar kinetics. The inflammatory cells in bronchoalveolar lavage fluid reached a maximum of 3 days and decreased progressively thereafter. Histopathologic examination revealed that substantial airway inflammation persisted through day 28. The proportion of mucin-producing epithelial cells significantly increased after day 1, reached a maximum at day 3, and remained at this level until day 5. The AHR peaked on day 1 and normalized within 5 days. The pretreatment of antioxidant significantly reduced not only the increased ROS levels but also development of other phenotypes of asthma.

CONCLUSION

These results indicate that increased oxidative stress in the lung precedes other pivotal phenotypes of allergic airway disease, suggesting a critical role for increased oxidative stress in the induction of allergic airway inflammation.

Mitochondrial dysfunction increases allergic airway inflammation

The prevalence of allergies and asthma among the world's population has been steadily increasing due to environmental factors. It has been described that exposure to ozone, diesel exhaust particles, or tobacco smoke exacerbates allergic inflammation in the lungs. These environmental oxidants increase the levels of cellular reactive oxygen species (ROS) and induce mitochondrial dysfunction in the airway epithelium. In this study, we investigated the involvement of preexisting mitochondrial dysfunction in the exacerbation of allergic airway inflammation. After cellular oxidative insult induced by ragweed pollen extract (RWE) exposure, we have identified nine oxidatively damaged mitochondrial respiratory chain-complex and associated proteins. Out of these, the ubiquinol-cytochrome c reductase core II protein (UQCRC2) was found to be implicated in mitochondrial ROS generation from respiratory complex III. Mitochondrial dysfunction induced by deficiency of UQCRC2 in airway epithelium of sensitized BALB/c mice prior the RWE challenge increased the Ag-induced accumulation of eosinophils, mucin levels in the airways, and bronchial hyperresponsiveness. Deficiency of UQCRC1, another oxidative damage-sensitive complex III protein, did not significantly alter cellular ROS levels or the intensity of RWE-induced airway inflammation. These observations suggest that preexisting mitochondrial dysfunction induced by oxidant environmental pollutants is responsible for the severe symptoms in allergic airway inflammation. These data also imply that mitochondrial defects could be risk factors and may be responsible for severe allergic disorders in atopic individuals.

Breakdown in epithelial barrier function in patients with asthma: identification of novel therapeutic approaches

The bronchial epithelium is pivotally involved in the provision of chemical, physical, and immunologic barriers to the inhaled environment. These barriers serve to maintain normal homeostasis, but when compromised, the immunologic barrier becomes activated to protect the internal milieu of the lung. We discuss what is currently understood about abnormalities in these barrier functions in patients with asthma and consider novel therapeutic opportunities that target this key structure.

Gene expression profiling of experimental asthma reveals a possible role of paraoxonase-1 in the disease

In this study, we aimed to identify novel genes involved in experimental and human asthma, importance of which has not yet been recognized. In an ovalbumin-induced murine model of asthma, we applied microarray gene expression analysis at different time points after allergen challenges. Advanced statistical methods were used to relate gene expression changes to cellular processes and to integrate our results into multiple levels of information available in public databases. At 4 h after the first allergen challenge, gene expression pattern reflected mainly an acute, but non-atopic, inflammatory response and strong chemotactic activity. At 24 h after the third allergen challenge, gene set enrichment analysis revealed significant over-representation of gene sets corresponding to T(h)2-type inflammation models. Among the top down-regulated transcripts, an anti-oxidant enzyme, paraoxonase-1 (PON1), was identified. In human asthmatic patients, we found that serum PON1 activity was reduced at exacerbation, but increased parallel with improving asthma symptoms. PON1 gene polymorphisms did not influence the susceptibility to the disease. Our observations suggest that an altered PON1 activity might be involved in the pathogenesis of asthma, and serum PON1 level might be used for following up the effect of therapy.

Between a cough and a wheeze: dendritic cells at the nexus of tobacco smoke-induced allergic airway sensitization

Exposure to cigarette smoke represents a major risk factor for the development of asthma. Enhanced sensitization toward allergens has been observed in humans and laboratory animals exposed to cigarette smoke. Pulmonary dendritic cells (DCs) are crucially involved in sensitization toward allergens and play an important role in the development of T helper (Th)2-mediated allergic airway inflammation. We propose the concept that aberrant DC activation forms the basis for the deviation of the lung's default tolerogenic response toward allergic inflammation when harmless antigens are concomittantly inhaled with tobacco smoke. This review will summarize evidence suggesting that tobacco smoke can achieve this effect by providing numerous triggers of innate immunity, which can profoundly modulate airway DC biology. Tobacco smoke can affect the airway DC network either directly or indirectly by causing the release of DC-targeted mediators from the pulmonary tissue environment, resulting in the induction of a Th2-oriented pathological immune response. A thorough knowledge of the molecular pathways involved may open the door to novel approaches in the treatment of asthma.

Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway

BACKGROUND

Cellular oxidative stress is an important factor in asthma and is thought to be the principle mechanism by which oxidant pollutants such as ozone and particulates mediate their pro-inflammatory effects. Endogenous Phase II enzymes abrogate oxidative stress through the scavenging of reactive oxygen species and metabolism of reactive chemicals.

OBJECTIVE

We conducted a placebo-controlled dose escalation trial to investigate the in vivo effects of sulforaphane, a naturally occurring potent inducer of Phase II enzymes, on the expression of glutathione-s-transferase M1 (GSTM1), glutathione-s-transferase P1 (GSTP1), NADPH quinone oxidoreductase (NQO1), and hemoxygenase-1 (HO-1) in the upper airway of human subjects.

METHODS

Study subjects consumed oral sulforaphane doses contained in a standardized broccoli sprout homogenate (BSH). RNA expression for selected Phase II enzymes was measured in nasal lavage cells by RT-PCR before and after sulforaphane dosing.

RESULTS

All subjects tolerated oral sulforaphane dosing without significant adverse events. Increased Phase II enzyme expression in nasal lavage cells occurred in a dose-dependent manner with maximal enzyme induction observed at the highest dose of 200 g broccoli sprouts prepared as BSH. Significant increases were seen in all sentinel Phase II enzymes RNA expression compared to baseline. Phase II enzyme induction was not seen with ingestion of non-sulforaphane containing alfalfa sprouts.

CONCLUSION

Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects. This study demonstrates the potential of antioxidant Phase II enzymes induction in the human airway as a strategy to reduce the inflammatory effects of oxidative stress.

CLINICAL IMPLICATIONS

This study demonstrates the potential of enhancement of Phase II enzyme expression as a novel therapeutic strategy for oxidant induced airway disease.

CAPSULE SUMMARY

A placebo-controlled dose escalation trial demonstrated that naturally occurring sulforaphane from broccoli sprouts can induce a potent increase in antioxidant Phase II enzymes in airway cells.

Oral sulforaphane increases Phase II antioxidant enzymes in the human upper airway

BACKGROUND

Cellular oxidative stress is an important factor in asthma and is thought to be the principle mechanism by which oxidant pollutants such as ozone and particulates mediate their pro-inflammatory effects. Endogenous Phase II enzymes abrogate oxidative stress through the scavenging of reactive oxygen species and metabolism of reactive chemicals.

OBJECTIVE

We conducted a placebo-controlled dose escalation trial to investigate the in vivo effects of sulforaphane, a naturally occurring potent inducer of Phase II enzymes, on the expression of glutathione-s-transferase M1 (GSTM1), glutathione-s-transferase P1 (GSTP1), NADPH quinone oxidoreductase (NQO1), and hemoxygenase-1 (HO-1) in the upper airway of human subjects.

METHODS

Study subjects consumed oral sulforaphane doses contained in a standardized broccoli sprout homogenate (BSH). RNA expression for selected Phase II enzymes was measured in nasal lavage cells by RT-PCR before and after sulforaphane dosing.

RESULTS

All subjects tolerated oral sulforaphane dosing without significant adverse events. Increased Phase II enzyme expression in nasal lavage cells occurred in a dose-dependent manner with maximal enzyme induction observed at the highest dose of 200 g broccoli sprouts prepared as BSH. Significant increases were seen in all sentinel Phase II enzymes RNA expression compared to baseline. Phase II enzyme induction was not seen with ingestion of non-sulforaphane containing alfalfa sprouts.

CONCLUSION

Oral sulforaphane safely and effectively induces mucosal Phase II enzyme expression in the upper airway of human subjects. This study demonstrates the potential of antioxidant Phase II enzymes induction in the human airway as a strategy to reduce the inflammatory effects of oxidative stress.

CLINICAL IMPLICATIONS

This study demonstrates the potential of enhancement of Phase II enzyme expression as a novel therapeutic strategy for oxidant induced airway disease.

CAPSULE SUMMARY

A placebo-controlled dose escalation trial demonstrated that naturally occurring sulforaphane from broccoli sprouts can induce a potent increase in antioxidant Phase II enzymes in airway cells.

Impact of innate immunity in a subset of children with autism spectrum disorders: a case control study

Background

Among patients with autism spectrum disorders (ASD) evaluated in our clinic, there appears to be a subset that can be clinically distinguished from other ASD children because of frequent infections (usually viral) accompanied by worsening behavioural symptoms and/or loss/decrease in acquired skills. This study assessed whether these clinical features of this ASD subset are associated with atopy, asthma, food allergy (FA), primary immunodeficiency (PID), or innate immune responses important in viral infections.

Methods

This study included the ASD children described above (ASD test, N = 26) and the following controls: ASD controls (N = 107), non-ASD controls with FA (N = 24), non-ASD controls with chronic rhinosinusitis/recurrent otitis media (CRS/ROM; N = 38), and normal controls (N = 43). We assessed prevalence of atopy, asthma, FA, CRS/ROM, and PID. Innate immune responses were assessed by measuring production of proinflammatory and counter-regulatory cytokines by peripheral blood mononuclear cells (PBMCs) in response to agonists of Toll-like receptors (TLRs), with or without pre-treatment of lipopolysaccharide (LPS), a TLR4 agonist.

Results

Non-IgE mediated FA was equally prevalent in both ASD test and ASD control groups, occurring at higher frequency than in the non-ASD controls. Allergic rhinitis, atopic/non-atopic asthma, and atopic dermatitis were equally prevalent among the study groups except for the CRS/ROM group in which non-atopic asthma was more prevalent (52.6%). CRS/ROM and specific polysaccharide antibody deficiency (SPAD) were more prevalent in the ASD test group than in the ASD control, FA, and normal control groups: 23.1% vs. < 5% for CRS/ROS and 19.2% vs. < 1% for SPAD. However, CRS/ROM patients had the highest prevalence of SPAD (34.2%). When compared to ASD and normal case controls, PBMCs from 19 non-SPAD, ASD test group children produced: 1) less IL-1β with a TLR7/8 agonist, less IL-10 with a TLR2/6 agonist, and more IL-23 with a TLR4 agonist without LPS pre-treatment, and 2) less IL-1β with TLR4/7/8 agonists with LPS pre-treatment. These are cytokines associated with the neuro-immune network.

Conclusion

Clinical features of the ASD test group were not associated with atopy, asthma, FA, or PID in our study but may be associated with altered TLR responses mediating neuro-immune interactions.

Molecular mechanisms and clinical implications of reversible protein S-glutathionylation

Sulfhydryl chemistry plays a vital role in normal biology and in defense of cells against oxidants, free radicals, and electrophiles. Modification of critical cysteine residues is an important mechanism of signal transduction, and perturbation of thiol-disulfide homeostasis is an important consequence of many diseases. A prevalent form of cysteine modification is reversible formation of protein mixed disulfides (protein-SSG) with glutathione (GSH). The abundance of GSH in cells and the ready conversion of sulfenic acids and S-nitroso derivatives to S-glutathione mixed disulfides suggests that reversible S-glutathionylation may be a common feature of redox signal transduction and regulation of the activities of redox sensitive thiol-proteins. The glutaredoxin enzyme has served as a focal point and important tool for evolution of this regulatory mechanism, because it is a specific and efficient catalyst of protein-SSG deglutathionylation. However, mechanisms of control of intracellular Grx activity in response to various stimuli are not well understood, and delineation of specific mechanisms and enzyme(s) involved in formation of protein-SSG intermediates requires further attention. A large number of proteins have been identified as potentially regulated by reversible S-glutathionylation, but only a few studies have documented glutathionylation-dependent changes in activity of specific proteins in a physiological context. Oxidative stress is a hallmark of many diseases which may interrupt or divert normal redox signaling and perturb protein-thiol homeostasis. Examples involving changes in S-glutathionylation of specific proteins are discussed in the context of diabetes, cardiovascular and lung diseases, cancer, and neurodegenerative diseases.