Glutathione S-transferase M1 (GSTM1) is a phase II enzyme and regulator of inflammatory signaling... more Glutathione S-transferase M1 (GSTM1) is a phase II enzyme and regulator of inflammatory signaling in airway epithelial cells. We have found upregulation of neutrophilic airway inflammation in atopic asthmatics expressing GSTM1 gene (GSTM1+) compared to GSTM1null asthmatics. We hypothesized that GSTM1 modulates NF-κB activation in bronchial epithelium in atopic asthmatics. We determined regulation of allergen-induced NF-κB activation in bronchial epithelium by GSTM1 in human atopic asthmatics in vivo. Endobronchial biopsies and bronchoalveolar lavage fluid samples were collected from 13 GSTM1+ and 12 GSTM1null human atopic asthmatics at baseline and 24 h after segmental allergen challenge. A quantitative analysis of NF-κB activation in airway epithelium was accomplished using a polyclonal antibody against the phosphorylated p65 component of NF-κB. Elastase-positive neutrophils in the bronchial wall were quantified. Postallergen neutrophilia in airway subepithelium and epithelial lini...
American Journal of Respiratory and Critical Care Medicine, 2013
Asthma is a heterogeneous lung disorder characterized by airway inflammation and airway dysfuncti... more Asthma is a heterogeneous lung disorder characterized by airway inflammation and airway dysfunction, manifesting as hyperresponsiveness and obstruction. Glutathione S-transferase M1 (GSTM1) is a multifunctional phase II enzyme and regulator of stress-activated cellular signaling relevant to asthma pathobiology. A common homozygous deletion polymorphism of the GSTM1 gene eliminates enzyme activity. To determine the effect of GSTM1 on airway inflammation and reactivity in adults with established atopic asthma in vivo. Nineteen GSTM1 wild-type and eighteen GSTM1-null individuals with mild atopic asthma underwent methacholine and inhaled allergen challenges, and endobronchial allergen provocations through a bronchoscope. The influx of inflammatory cells, panels of cytokines and chemokines linked to asthmatic inflammation, F(2)-isoprostanes (markers of oxidative stress), and IgE were measured in bronchoalveolar lavage fluid at baseline and 24 hours after allergen instillation. Individuals with asthma with the GSTM1 wild-type genotype had greater baseline and allergen-provoked airway neutrophilia and concentrations of myeloperoxidase than GSTM1-null patients. In contrast, the eosinophilic inflammation was unaffected by GSTM1. The allergen-stimulated generation of acute-stress and proneutrophilic mediators, tumor necrosis factor-α, CXCL-8, IL-1β, and IL-6, was also greater in the GSTM1 wild-type patients. Moreover, post-allergen airway concentrations of IgE and neutrophil-generated mediators, matrix metalloproteinase-9, B-cell activating factor, transforming growth factor-β1, and elastase were higher in GSTM1 wild-type individuals with asthma. Total airway IgE correlated with B-cell activating factor concentrations. In contrast, levels of F(2)-isoprostane were comparable in both groups. Finally, GSTM1 wild-type individuals with asthma required lower threshold concentrations of allergen to produce bronchoconstriction. The functional GSTM1 genotype promotes neutrophilic airway inflammation in humans with atopic asthma in vivo.
Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response ... more Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response to infection or allergen. Controversy surrounds their role in exacerbations of human atopic asthma. To determine the effect of allergen challenge on iNKT cells' mobilization to the airways and blood and to establish the relationship between airway iNKT cells and bronchial sensitivity to methacholine and allergen in patients with atopic asthma. We performed flow cytometry analysis for the iNKT cell receptor Va24 and V311 on bronchoalveolar lavage (BAL) cells at baseline and 24 hours after segmental antigen challenge (SAC) (n = 8) and on peripheral blood mononuclear cells (PBMCs) at baseline and 6 to 7 hours after inhaled allergen (n = 10). Challenges were performed using standardized protein allergens to which the participants were sensitive. The number of BAL eosinophils increased 24 hours after SAC. The low mean (SEM) baseline percentage of iNKT cells in the population of BAL CD4' T cells remained unchanged 24 hours after SAC (0.035% [0.01%] vs 0.049% [0.02%]; n = 8; P = .50). Likewise, the mean (SEM) percentage of iNKT cells in PBMCs was unchanged after inhaled allergen provocation (0.068% [0.033%] vs 0.057% [0.026%]; n = 10; P = .10). No correlation was found between iNKT cells in BAL and the sensitivity to inhaled methacholine or allergen. The percentages of both BAL and peripheral blood iNKT cells did not increase during allergen provoked asthmatic responses. Determination of iNKT cells in airway biopsy specimens would allow conclusively ruling against mobilization of iNKT cells in allergen-induced asthma exacerbation in humans.
Glutathione S-transferase M1 (GSTM1) is a phase II enzyme and regulator of inflammatory signaling... more Glutathione S-transferase M1 (GSTM1) is a phase II enzyme and regulator of inflammatory signaling in airway epithelial cells. We have found upregulation of neutrophilic airway inflammation in atopic asthmatics expressing GSTM1 gene (GSTM1+) compared to GSTM1null asthmatics. We hypothesized that GSTM1 modulates NF-κB activation in bronchial epithelium in atopic asthmatics. We determined regulation of allergen-induced NF-κB activation in bronchial epithelium by GSTM1 in human atopic asthmatics in vivo. Endobronchial biopsies and bronchoalveolar lavage fluid samples were collected from 13 GSTM1+ and 12 GSTM1null human atopic asthmatics at baseline and 24 h after segmental allergen challenge. A quantitative analysis of NF-κB activation in airway epithelium was accomplished using a polyclonal antibody against the phosphorylated p65 component of NF-κB. Elastase-positive neutrophils in the bronchial wall were quantified. Postallergen neutrophilia in airway subepithelium and epithelial lini...
American Journal of Respiratory and Critical Care Medicine, 2013
Asthma is a heterogeneous lung disorder characterized by airway inflammation and airway dysfuncti... more Asthma is a heterogeneous lung disorder characterized by airway inflammation and airway dysfunction, manifesting as hyperresponsiveness and obstruction. Glutathione S-transferase M1 (GSTM1) is a multifunctional phase II enzyme and regulator of stress-activated cellular signaling relevant to asthma pathobiology. A common homozygous deletion polymorphism of the GSTM1 gene eliminates enzyme activity. To determine the effect of GSTM1 on airway inflammation and reactivity in adults with established atopic asthma in vivo. Nineteen GSTM1 wild-type and eighteen GSTM1-null individuals with mild atopic asthma underwent methacholine and inhaled allergen challenges, and endobronchial allergen provocations through a bronchoscope. The influx of inflammatory cells, panels of cytokines and chemokines linked to asthmatic inflammation, F(2)-isoprostanes (markers of oxidative stress), and IgE were measured in bronchoalveolar lavage fluid at baseline and 24 hours after allergen instillation. Individuals with asthma with the GSTM1 wild-type genotype had greater baseline and allergen-provoked airway neutrophilia and concentrations of myeloperoxidase than GSTM1-null patients. In contrast, the eosinophilic inflammation was unaffected by GSTM1. The allergen-stimulated generation of acute-stress and proneutrophilic mediators, tumor necrosis factor-α, CXCL-8, IL-1β, and IL-6, was also greater in the GSTM1 wild-type patients. Moreover, post-allergen airway concentrations of IgE and neutrophil-generated mediators, matrix metalloproteinase-9, B-cell activating factor, transforming growth factor-β1, and elastase were higher in GSTM1 wild-type individuals with asthma. Total airway IgE correlated with B-cell activating factor concentrations. In contrast, levels of F(2)-isoprostane were comparable in both groups. Finally, GSTM1 wild-type individuals with asthma required lower threshold concentrations of allergen to produce bronchoconstriction. The functional GSTM1 genotype promotes neutrophilic airway inflammation in humans with atopic asthma in vivo.
Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response ... more Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response to infection or allergen. Controversy surrounds their role in exacerbations of human atopic asthma. To determine the effect of allergen challenge on iNKT cells' mobilization to the airways and blood and to establish the relationship between airway iNKT cells and bronchial sensitivity to methacholine and allergen in patients with atopic asthma. We performed flow cytometry analysis for the iNKT cell receptor Va24 and V311 on bronchoalveolar lavage (BAL) cells at baseline and 24 hours after segmental antigen challenge (SAC) (n = 8) and on peripheral blood mononuclear cells (PBMCs) at baseline and 6 to 7 hours after inhaled allergen (n = 10). Challenges were performed using standardized protein allergens to which the participants were sensitive. The number of BAL eosinophils increased 24 hours after SAC. The low mean (SEM) baseline percentage of iNKT cells in the population of BAL CD4' T cells remained unchanged 24 hours after SAC (0.035% [0.01%] vs 0.049% [0.02%]; n = 8; P = .50). Likewise, the mean (SEM) percentage of iNKT cells in PBMCs was unchanged after inhaled allergen provocation (0.068% [0.033%] vs 0.057% [0.026%]; n = 10; P = .10). No correlation was found between iNKT cells in BAL and the sensitivity to inhaled methacholine or allergen. The percentages of both BAL and peripheral blood iNKT cells did not increase during allergen provoked asthmatic responses. Determination of iNKT cells in airway biopsy specimens would allow conclusively ruling against mobilization of iNKT cells in allergen-induced asthma exacerbation in humans.
Uploads
Papers by Aimee Hoskins