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Marina Miller,
Arvin B Tam,
Jae Youn Cho,
Taylor A Doherty,
Alexa Pham,
Naseem Khorram,
Peter Rosenthal,
James L Mueller,
Hal M Hoffman,
Maho Suzukawa,
Maho Niwa,
David H Broide
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ABSTRACT: Orosomucoid like 3 (ORMDL3) has been strongly linked with asthma in genetic association studies, but its function in asthma is unknown. We demonstrate that in mice ORMDL3 is an allergen and cytokine (IL-4 or IL-13) inducible endoplasmic reticulum (ER) gene expressed predominantly in airway epithelial cells. Allergen challenge induces a 127-fold increase in ORMDL3 mRNA in bronchial epithelium in WT mice, with lesser 15-fold increases in ORMDL-2 and no changes in ORMDL-1. Studies of STAT-6-deficient mice demonstrated that ORMDL3 mRNA induction highly depends on STAT-6. Transfection of ORMDL3 in human bronchial epithelial cells in vitro induced expression of metalloproteases (MMP-9, ADAM-8), CC chemokines (CCL-20), CXC chemokines (IL-8, CXCL-10, CXCL-11), oligoadenylate synthetases (OAS) genes, and selectively activated activating transcription factor 6 (ATF6), an unfolded protein response (UPR) pathway transcription factor. siRNA knockdown of ATF-6α in lung epithelial cells inhibited expression of SERCA2b, which has been implicated in airway remodeling in asthma. In addition, transfection of ORMDL3 in lung epithelial cells activated ATF6α and induced SERCA2b. These studies provide evidence of the inducible nature of ORMDL3 ER expression in particular in bronchial epithelial cells and suggest an ER UPR pathway through which ORMDL3 may be linked to asthma.
Proceedings of the National Academy of Sciences 09/2012; 109(41):16648-53. · 9.68 Impact Factor
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ABSTRACT: The fungal allergen, Alternaria, is specifically associated with severe asthma, including life-threatening exacerbations. To better understand the acute innate airway response to Alternaria, naive wild-type (WT) mice were challenged once intranasally with Alternaria. Naive WT mice developed significant bronchoalveolar lavage eosinophilia following Alternaria challenge when analyzed 24 h later. In contrast to Alternaria, neither Aspergillus nor Candida induced bronchoalveolar lavage eosinophilia. Gene microarray analysis of airway epithelial cell brushings demonstrated that Alternaria-challenged naive WT mice had a >20-fold increase in the level of expression of found in inflammatory zone 1 (FIZZ1/Retnla), a resistin-like molecule. Lung immunostaining confirmed strong airway epithelial FIZZ1 expression as early as 3 h after a single Alternaria challenge that persisted for ≥5 d and was significantly reduced in STAT6-deficient, but not protease-activated receptor 2-deficient mice. Bone marrow chimera studies revealed that STAT6 expressed in lung cells was required for epithelial FIZZ1 expression, whereas STAT6 present in bone marrow-derived cells contributed to airway eosinophilia. Studies investigating which cells in the nonchallenged lung bind FIZZ1 demonstrated that CD45(+)CD11c(+) cells (macrophages and dendritic cells), as well as collagen-1-producing CD45(-) cells (fibroblasts), can bind to FIZZ1. Importantly, direct administration of recombinant FIZZ1 to naive WT mice led to airway eosinophilia, peribronchial fibrosis, and increased thickness of the airway epithelium. Thus, Alternaria induces STAT6-dependent acute airway eosinophilia and epithelial FIZZ1 expression that promotes airway fibrosis and epithelial thickness. This may provide some insight into the uniquely pathogenic aspects of Alternaria-associated asthma.
The Journal of Immunology 03/2012; 188(6):2622-9. · 5.79 Impact Factor
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ABSTRACT: Eosinophilic esophagitis (EoE) is a disorder characterized histologically by tissue eosinophilia. Sialic acid-binding immunoglobulin-like lectin (Siglec-F) is a receptor highly expressed on mouse eosinophils and mediates eosinophilic apoptosis. We investigated whether administration of an anti-Siglec-F Ab would reduce esophageal eosinophilic inflammation and remodeling in a mouse model of egg ovalbumin (OVA)-induced EoE.
Three groups of mice were studied (no OVA, OVA + anti-Siglec-F Ab, and OVA + isotype control Ab). Mice were sensitized intraperitoneally and then challenged chronically with intraesophageal OVA. Levels of esophageal eosinophils and features of remodeling (angiogenesis, vascular endothelial growth factor expression, deposition of fibronectin, basal zone hyperplasia, and fibrosis) were quantitated by immunohistochemistry and image analysis.
Administration of an anti-Siglec-F Ab to OVA-challenged mice significantly reduced levels of esophageal eosinophils, down to levels noted in non-OVA-challenged mice. The anti-Siglec-F Ab also reduced features of OVA-induced remodeling, including angiogenesis, basal zone hyperplasia, and fibronectin deposition. The reduced angiogenesis in anti-Siglec-F Ab-treated mice was associated with reduced numbers of vascular endothelial growth factor-positive cells in the esophagus. The anti-Siglec-F antibody did not significantly reduce esophageal fibrosis as assessed by trichrome staining.
Administration of an anti-Siglec-F antibody significantly decreased the number of eosinophils in the esophagus in a mouse model of OVA-induced EoE. The reduction in eosinophilic inflammation was associated with a significant decrease in levels of angiogenesis, deposition of fibronectin, and basal zone hyperplasia. Studies in this pre-clinical model of EoE suggest that Siglec-F (and its human paralog Siglec-8) may be novel therapeutic targets to reduce eosinophilic inflammation in EoE.
Journal of pediatric gastroenterology and nutrition 10/2011; 53(4):409-16. · 2.18 Impact Factor
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ABSTRACT: The role of tumor necrosis factor-α (TNF-α) in contributing to allergen induced airway remodeling in asthma is unknown. In this study we have utilized a mouse model of chronic OVA allergen induced airway remodeling to determine whether TNF p55/p75 receptor deficient mice (abbreviated TNF-R KO) had reduced levels of airway remodeling. Chronic OVA challenged WT mice had significantly increased levels of lung eosinophilic inflammation as well as features of airway remodeling including increased peribronchial fibrosis, thickness of the peribronchial smooth muscle layer, mucus expression, and deposition of extracellular matrix proteins. In contrast, TNF-R KO mice had significantly reduced levels of major basic protein positive peribronchial eosinophils and significantly reduced peribronchial fibrosis assessed by quantitating the area of peribronchial trichrome staining and total lung collagen. In addition, TNF-R KO mice had significantly reduced thickness of the peribronchial smooth muscle layer, area of peribronchial α-smooth muscle actin immunostaining, and levels of the extracellular matrix protein fibronectin. There was a non-significant trend for reduced mucus expression in TNF-R KO mice. Levels of peribronchial cells immunostaining positive for TGF-β1 were significantly reduced in TNF-R KO mice suggesting that reduced levels of TGF-β1 expression in TNF-R KO mice may contribute to reduced airway remodeling. Overall, this study suggests an important role for TNF-α in contributing to many features of allergen induced airway remodeling including changes in levels of peribronchial smooth muscle, subepithelial fibrosis, and deposition of extracellular matrix.
International immunopharmacology 03/2011; 11(8):1038-44. · 2.21 Impact Factor
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ABSTRACT: Basic fibroblast growth factor (bFGF) is a cytokine that is mitogenic for fibroblasts and smooth muscle and may play a role in airway remodeling in asthma. We have used a mouse model of chronic ovalbumin (OVA) allergen-induced airway remodeling to determine whether bFGF and fibroblast growth factor receptor-1 are expressed and regulated by corticosteroids in the airway, as well as to determine whether bFGF mediates expression of another proremodeling cytokine, transforming growth factor (TGF)-β1.
The airway levels and localization of bFGF, FGF receptor-1 and TGF-β1 were determined by ELISA, immunohistology and image analysis in the remodeled airways of chronic OVA-challenged mice treated with either corticosteroids or diluent. In vitro cultures of bone narrow-derived macrophages were used to determine whether bFGF induced TGF-β1 expression.
Mice chronically challenged with OVA developed significant airway remodeling that was associated with significantly increased levels of bFGF and TGF-β1. Immunohistochemistry demonstrated significantly increased bFGF and FGF receptor-1 expression by peri- bronchial F4/80+ cells. Double-label immunofluorescence microscopy studies demonstrated that peribronchial macrophages coexpressed bFGF and TGF-β1. In vitro studies demonstrated that incubation of bone marrow-derived macrophages with bFGF induced expression of TGF-β1. Mice treated with corticosteroids and subjected to chronic OVA challenge had significantly reduced levels of bFGF, FGF receptor-1, peribronchial TGF-β1+ cells and airway remodeling.
Overall, this study demonstrates that allergen challenge stimulates peribronchial macrophages to coexpress bFGF and TGF-β1 and that bFGF may potentiate macrophage release of TGF-β1 through autocrine and/or paracrine pathways.
International Archives of Allergy and Immunology 11/2010; 155(1):12-22. · 2.40 Impact Factor
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ABSTRACT: In this study we examined the role of Siglec-F, a receptor highly expressed on eosinophils, in contributing to mucus expression, airway remodeling, and Siglec-F ligand expression utilizing Siglec-F deficient mice exposed to chronic allergen challenge.
Wild type (WT) and Siglec-F deficient mice were sensitized and challenged chronically with OVA for one month. Levels of airway inflammation (eosinophils), Siglec-F ligand expresion and remodeling (mucus, fibrosis, smooth muscle thickness, extracellular matrix protein deposition) were assessed in lung sections by image analysis and immunohistology. Airway hyperreactivity to methacholine was assessed in intubated and ventilated mice.
Siglec-F deficient mice challenged with OVA for one month had significantly increased numbers of BAL and peribronchial eosinophils compared to WT mice which was associated with a significant increase in mucus expression as assessed by the number of periodic acid Schiff positive airway epithelial cells. In addition, OVA challenged Siglec-F deficient mice had significantly increased levels of peribronchial fibrosis (total lung collagen, area of peribronchial trichrome staining), as well as increased numbers of peribronchial TGF-β1+ cells, and increased levels of expression of the extracellular matrix protein fibronectin compared to OVA challenged WT mice. Lung sections immunostained with a Siglec-Fc to detect Siglec-F ligand expression demonstrated higher levels of expression of the Siglec-F ligand in the peribronchial region in OVA challenged Siglec-F deficient mice compared to WT mice. WT and Siglec-F deficient mice challenged intranasally with IL-4 or IL-13 had significantly increased levels of airway epithelial Siglec-F ligand expression, whereas this was not observed in WT or Siglec-F deficient mice challenged with TNF-α. There was a significant increase in the thickness of the peribronchial smooth muscle layer in OVA challenged Siglec-F deficient mice, but this was not associated with significant increased airway hyperreactivity compared to WT mice.
Overall, this study demonstrates an important role for Siglec-F in modulating levels of chronic eosinophilic airway inflammation, peribronchial fibrosis, thickness of the smooth muscle layer, mucus expression, fibronectin, and levels of peribronchial Siglec-F ligands suggesting that Siglec-F may normally function to limit levels of chronic eosinophilic inflammation and remodeling. In addition, IL-4 and IL-13 are important regulators of Siglec-F ligand expression by airway epithelium.
Respiratory research 11/2010; 11:154. · 3.36 Impact Factor
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ABSTRACT: Adiponectin is a cytokine with both proinflammatory and anti-inflammatory properties that is expressed in epithelial cells in the airway in chronic obstructive pulmonary disease-emphysema (COPD-E). To determine whether adiponectin modulates levels of lung inflammation in tobacco smoke-induced COPD-E, we used a mouse model of COPD-E in which either adiponectin-deficient or wild-type (WT) mice were exposed to tobacco smoke for 6 mo. Outcomes associated with tobacco smoke-induced COPD-E were quantitated including lung inflammation [bronchoalveolar lavage (BAL) and total and differential cell count], lung mediators of inflammation (cytokines and chemokines), air space enlargement (i.e., linear intercept), and lung function (tissue elastance) in the different groups of mice. Whereas exposure of WT mice to tobacco smoke for 6 mo induced significant lung inflammation (increased total BAL cells, neutrophils, and macrophages), adiponectin-deficient mice had minimal BAL inflammation when exposed to tobacco smoke for 6 mo. In addition, whereas chronic tobacco-exposed WT mice had significantly increased levels of lung mediators of inflammation [i.e., TNF-α, keratinocyte-derived chemokine (KC), and adiponectin] as well as significantly increased air space enlargement (increased linear intercept) and decreased tissue elastance, exposure of adiponectin-deficient mice to chronic tobacco smoke resulted in no further increase in lung mediators, air space enlargement, or tissue elastance. In vitro studies demonstrated that BAL macrophages derived from adiponectin-deficient mice incubated in media containing tobacco smoke expressed minimal TNF-α or KC compared with BAL macrophages from WT mice. These studies suggest that adiponectin plays an important proinflammatory role in tobacco smoke-induced COPD-E.
AJP Lung Cellular and Molecular Physiology 10/2010; 299(6):L834-42. · 3.66 Impact Factor
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ABSTRACT: Tobacco smoking is a principal cause of COPD-emphysema (COPD-E). Whether discontinuing smoking for at least 4 years halts airway inflammation and progression of COPD-E in prior smokers is unknown. In this study we investigated whether discontinuing smoking for approximately 4 years in ex-smokers with GOLD (Global Initiative for Chronic Lung Disease) stage IIb (moderately severe) COPD-E stopped airway inflammation (ie, sputum biomarkers) and halted the progression of COPD-E on chest CT scan.
Ten ex-smokers with COPD-E who had quit smoking underwent chest CT scans to document the extent of COPD-E, assessment of lung function (FEV(1) and diffusing capacity of lung for carbon monoxide), sputum induction for biomarkers of inflammation (measured by enzyme-linked immunosorbent assay), and blood cotinine levels at baseline and approximately 4 years later. Normal healthy subjects (n = 7) and normal current smokers with no CT scan evidence of COPD-E (n = 8) served as sputum biomarker comparison groups.
After approximately 4 years of not smoking (documented by cotinine levels), ex-smokers with COPD-E had persistent increased levels of mediators of inflammation in sputum (myeloperoxidase, leukotriene B4, IL-8, monocyte chemoattractant protein-1, matrix metalloprotease-9), which was associated with significant progression of COPD-E on chest CT scan.
Cessation of tobacco smoking in heavy smokers with moderately severe COPD-E is associated with evidence of persistent airway inflammation and progression of COPD-E on CT scan 4 years later. Discontinuing smoking may slow the rate of progression of moderate severity COPD-E, but it does not prevent persistent airway inflammation and significant progression of COPD-E on CT scan.
Chest 10/2010; 139(6):1380-7. · 5.25 Impact Factor
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ABSTRACT: As genetically engineered mutant mice deficient in single genes are usually generated on a C57BL/6 background, to study mast cell trafficking in mutant mice, we initially investigated whether mast cells accumulated in bronchi in C57BL/6 mice challenged with OVA allergen acutely or chronically for 1 to 3 months. The total number of bronchial mast cells were quantitated using toluidine blue staining in airways of different sizes, i.e. , small (<90 microm), medium (90-155 microm), or large (>150 microm) airways. Non-OVA challenged and acute OVA challenged mice (C57BL/6 and BALB/c) had no detectable bronchial mast cells. Chronic OVA challenge in BALB/c mice for 1 or 3 months induced a significant increase in the number of bronchial mast cells in small-, medium-, and large-sized airways but minimal change in the number of bronchial mast cells in C57BL/6 mice. Both BALB/c and C57BL/6 mice developed significant lung eosinophilia following acute or chronic OVA challenge. Studies of IL-9-deficient mice on a BALB/c background demonstrated a significant increase in the number of bronchial mast cells in IL-9-deficient mice suggesting that IL-9 was not required for the bronchial accumulation of mast cells. Overall, these studies demonstrate that the chronic OVA challenge protocol we have utilized in BALB/c mice provides a model to study the mechanism of bronchial mast cell accumulation and that bronchial mast cell accumulation in chronic OVA challenged mice is independent of IL-9 in this model.
Immunogenetics 08/2010; 62(8):499-506. · 2.93 Impact Factor
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ABSTRACT: We have examined the role of NF-kappaB regulated genes in airway epithelium in mediating tobacco smoke induced airway inflammation in studies of CC10-Cre(tg)/Ikk beta(Delta/Delta) mice in which NF-kappaB signaling through I kappaB-kinase-beta (IKK-beta) is selectively ablated in epithelial cells in the airway. CC10-Cre(tg)/Ikk beta(Delta/Delta) mice exposed to tobacco smoke for seven days had a significant decrease in the number of BAL cells (total cells, neutrophils, and macrophages) as well as significantly reduced numbers of peribronchial cells (F4/80+ and myeloperoxidase+) compared to tobacco exposed WT mice. In addition to the reduction in peribronchial cells, CC10-Cre(tg)/Ikk beta(Delta/Delta) mice exposed to tobacco smoke had a significant decrease in the number of macrophages and neutrophils in the alveolar space suggesting that inactivation of NF-kappaB in the airway epithelium influenced the number of neutrophils and macrophages recruited to the alveolus. Levels of the NF-kappaB regulated chemokines KC and MCP-1 were significantly reduced in lungs of tobacco smoke exposed CC10-Cre(tg)/Ikk beta(Delta/Delta) mice compared to tobacco exposed WT mice. In contrast, there was no significant difference in levels of NF-kappaB regulated MIP-1 alpha between CC10-Cre(tg)/Ikk beta(Delta/Delta) and WT mice. Lung sections of tobacco smoke exposed CC10-Cre(tg)/Ikk beta(Delta/Delta) mice immunostained with KC or MCP-1 antibodies demonstrated reduced expression of these chemokines in the airway epithelium, but not in alveolar epithelium. Overall, these studies demonstrate an important role for NF-kappaB regulated genes in airway epithelium in contributing to acute tobacco smoke induced airway inflammation not only in the peribronchial space but also in the alveolar space.
International immunopharmacology 08/2010; 10(8):906-12. · 2.21 Impact Factor
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ABSTRACT: Abstract Background In this study we examined the role of Siglec-F, a receptor highly expressed on eosinophils, in contributing to mucus expression, airway remodeling, and Siglec-F ligand expression utilizing Siglec-F deficient mice exposed to chronic allergen challenge. Methods Wild type (WT) and Siglec-F deficient mice were sensitized and challenged chronically with OVA for one month. Levels of airway inflammation (eosinophils), Siglec-F ligand expresion and remodeling (mucus, fibrosis, smooth muscle thickness, extracellular matrix protein deposition) were assessed in lung sections by image analysis and immunohistology. Airway hyperreactivity to methacholine was assessed in intubated and ventilated mice. Results Siglec-F deficient mice challenged with OVA for one month had significantly increased numbers of BAL and peribronchial eosinophils compared to WT mice which was associated with a significant increase in mucus expression as assessed by the number of periodic acid Schiff positive airway epithelial cells. In addition, OVA challenged Siglec-F deficient mice had significantly increased levels of peribronchial fibrosis (total lung collagen, area of peribronchial trichrome staining), as well as increased numbers of peribronchial TGF-β1+ cells, and increased levels of expression of the extracellular matrix protein fibronectin compared to OVA challenged WT mice. Lung sections immunostained with a Siglec-Fc to detect Siglec-F ligand expression demonstrated higher levels of expression of the Siglec-F ligand in the peribronchial region in OVA challenged Siglec-F deficient mice compared to WT mice. WT and Siglec-F deficient mice challenged intranasally with IL-4 or IL-13 had significantly increased levels of airway epithelial Siglec-F ligand expression, whereas this was not observed in WT or Siglec-F deficient mice challenged with TNF-α. There was a significant increase in the thickness of the peribronchial smooth muscle layer in OVA challenged Siglec-F deficient mice, but this was not associated with significant increased airway hyperreactivity compared to WT mice. Conclusions Overall, this study demonstrates an important role for Siglec-F in modulating levels of chronic eosinophilic airway inflammation, peribronchial fibrosis, thickness of the smooth muscle layer, mucus expression, fibronectin, and levels of peribronchial Siglec-F ligands suggesting that Siglec-F may normally function to limit levels of chronic eosinophilic inflammation and remodeling. In addition, IL-4 and IL-13 are important regulators of Siglec-F ligand expression by airway epithelium.
Respiratory Research. 01/2010;
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ABSTRACT: As passive environmental tobacco smoke (ETS) exposure in nonsmokers can increase both asthma symptoms and the frequency of asthma exacerbations, we utilized a mouse model, in which ovalbumin (OVA) + ETS induce significantly increased levels of eosinophilic airway inflammation and remodeling compared to either stimulus alone, to determine whether a Toll-like receptor-9 (TLR-9) agonist could reduce levels of airway inflammation, airway remodeling and airway hyperreactivity (AHR).
Mice treated with or without a TLR-9 agonist were sensitized to OVA and challenged with OVA + ETS for 1 month. AHR to methacholine was assessed in intubated and ventilated mice. Lung Th2 cytokines and TGF-beta(1) were measured by ELISA. Lungs were processed for histology and immunohistology to quantify eosinophils, mucus, peribronchial fibrosis and smooth muscle changes using image analysis.
Administration of a TLR-9 agonist to mice coexposed to chronic ETS and chronic OVA allergen significantly reduced levels of eosinophilic airway inflammation, mucus production, peribronchial fibrosis, the thickness of the peribronchial smooth muscle layer, and AHR. The reduced airway remodeling in mice treated with the TLR-9 agonist was associated with significantly reduced numbers of peribronchial MBP+ and peribronchial TGF-beta(1)+ cells, and with significantly reduced levels of lung Th2 cytokines [interleukin-5 and interleukin-13] and TGF-beta(1).
These studies demonstrate that TLR-9-based therapies inhibit airway inflammation, remodeling and AHR in mice coexposed to ETS and allergen who exhibit enhanced airway inflammation and remodeling.
International Archives of Allergy and Immunology 10/2009; 151(4):285-96. · 2.40 Impact Factor
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ABSTRACT: Siglec-F is a sialic acid-binding Ig superfamily receptor that is highly expressed on eosinophils. We have investigated whether administration of an anti-Siglec-F Ab to OVA-challenged wild-type mice would reduce levels of eosinophilic inflammation and levels of airway remodeling. Mice sensitized to OVA and challenged repetitively with OVA for 1 mo who were administered an anti-Siglec-F Ab had significantly reduced levels of peribronchial eosinophilic inflammation and significantly reduced levels of subepithelial fibrosis as assessed by either trichrome staining or lung collagen levels. The anti-Siglec-F Ab reduced the number of bone marrow, blood, and tissue eosinophils, suggesting that the anti-Siglec-F Ab was reducing the production of eosinophils. Administration of a F(ab')(2) fragment of an anti-Siglec-F Ab also significantly reduced levels of eosinophilic inflammation in the lung and blood. FACS analysis demonstrated increased numbers of apoptotic cells (annexin V(+)/CCR3(+) bronchoalveolar lavage and bone marrow cells) in anti-Siglec-F Ab-treated mice challenged with OVA. The anti-Siglec-F Ab significantly reduced the number of peribronchial major basic protein(+)/TGF-beta(+) cells, suggesting that reduced levels of eosinophil-derived TGF-beta in anti-Siglec-F Ab-treated mice contributed to reduced levels of peribronchial fibrosis. Administration of the anti-Siglec-F Ab modestly reduced levels of periodic acid-Schiff-positive mucus cells and the thickness of the smooth muscle layer. Overall, these studies suggest that administration of an anti-Siglec-F Ab can significantly reduce levels of allergen-induced eosinophilic airway inflammation and features of airway remodeling, in particular subepithelial fibrosis, by reducing the production of eosinophils and increasing the number of apoptotic eosinophils in lung and bone marrow.
The Journal of Immunology 09/2009; 183(8):5333-41. · 5.79 Impact Factor
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ABSTRACT: The ability of corticosteroids to reduce airway inflammation and improve lung function is significantly reduced in asthmatics who are tobacco smokers compared with asthmatics who are nonsmokers. As not only high levels of tobacco smoke exposure in active smokers, but also significantly lower levels of tobacco smoke exposure from passive environmental tobacco smoke (ETS) exposure in nonsmokers can increase both asthma symptoms and the frequency of asthma exacerbations, we utilized a mouse model to determine whether corticosteroids can reduce levels of airway inflammation, airway remodeling, and airway hyperreactivity in mice exposed to the combination of chronic ETS and ovalbumin (OVA) allergen. Chronic ETS exposure alone did not induce increases in eosinophilic airway inflammation, airway remodeling, or airway hyperreactivity. Mice exposed to chronic OVA allergen had significantly increased levels of peribronchial fibrosis, increased thickening of the smooth muscle layer, increased mucus, and increased airway hyperreactivity, which was significantly enhanced by coexposure to the combination of chronic ETS and chronic OVA allergen. Administration of corticosteroids to mice exposed to chronic ETS and OVA allergen significantly reduced levels of eosinophilic airway inflammation, mucus production, peribronchial smooth muscle thickness, airway hyperreactivity, and the number of peribronchial TGF-beta1+ cells. Overall, this study demonstrates that corticosteroids can significantly reduce levels of eosinophilic inflammation, mucus expression, airway remodeling, and airway hyperreactivity in chronic ETS-exposed mice challenged with allergen.
AJP Lung Cellular and Molecular Physiology 07/2009; 297(2):L380-7. · 3.66 Impact Factor
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ABSTRACT: We screened bronchoalveolar lavage (BAL) fluids from COPD-E (chronic obstructive pulmonary disease-Emphysema) and control subjects using a 120 Ab cytokine array and demonstrated that adiponectin was highly expressed in BAL in COPD-E. An adiponectin ELISA confirmed that adiponectin was highly expressed in BAL in COPD-E compared with smokers and healthy control subjects. Immunohistochemistry studies of lung sections from subjects with COPD-E demonstrated that airway epithelial cells expressed significant levels of adiponectin and adiponectin receptor (AdipoR) 1 but not AdipoR2. In vitro studies with purified populations of human lung A549 epithelial cells demonstrated that they expressed both adiponectin and AdipoR1 (but not AdipoR2) as assessed by RT-PCR, Western blot, and immunohistochemistry. Lung A549 epithelial AdipoR1were functional as incubation with adiponectin induced release of IL-8, which was inhibited by small interfering RNA to AdipoR1. Using a mouse model of COPD, tobacco smoke exposure induced both evidence of COPD as well as increased levels of adiponectin in BAL fluid and increased adiponectin expression by airway epithelial cells. As adiponectin expression in adipocytes is dependent upon NF-kappaB we determined levels of adiponectin in tobacco smoke exposed CC10-Cre(tg)/Ikkbeta(Delta/Delta) mice (deficient in the ability to activate NF-kappaB in airway epithelium). These studies demonstrated that CC10-Cre(tg)/Ikkbeta(Delta/Delta) and wild-type mice had similar levels of BAL adiponectin and airway epithelial adiponectin immunostaining. Overall, these studies demonstrate the novel observation that adiponectin and functional AdipoR1are expressed by lung epithelial cells, suggesting a potential autocrine and/or paracrine pathway for adiponectin to activate epithelial cells in COPD-E.
The Journal of Immunology 02/2009; 182(1):684-91. · 5.79 Impact Factor
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ABSTRACT: Siglec-F is a sialic acid binding immunoglobulin-superfamily receptor that is highly expressed on eosinophils. We have used a mouse model of oral egg ovalbumin (OVA)-induced eosinophilic inflammation of the gastro-intestinal mucosa associated with diarrhea and weight loss to determine whether administering an anti-Siglec-F antibody would reduce levels of intestinal mucosal eosinophilic inflammation. Mice administered the anti-Siglec-F antibody had significantly lower levels of intestinal eosinophilic inflammation, and this was associated with reduced intestinal permeability changes, normalization of intestinal villous crypt height, and restoration of weight gain. The reduced numbers of intestinal eosinophils in anti-Siglec-F antibody treated mice was associated with significantly reduced numbers of bone marrow and peripheral blood eosinophils, but was not associated with significant changes in the numbers of proliferating or apoptotic jejunal eosinophils. In addition, the anti-Siglec-F Ab reduced Th2 cytokines and IgE levels. Overall, these studies demonstrate that administration of an anti-Siglec-F antibody significantly reduces levels of eosinophilic inflammation in the intestinal mucosa and that this was associated with reduced intestinal permeability changes, normalization of intestinal villous crypt height, and restoration of weight gain.
Clinical Immunology 02/2009; 131(1):157-69. · 4.05 Impact Factor
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ABSTRACT: In this study, we have examined the role of phosphoinositide 3 kinase gamma (PI3Kgamma), a class Ib PI3K, in contributing to airway remodeling utilizing PI3Kgamma-deficient mice exposed to chronic allergen challenge. Wild-type (WT) mice sensitized to ovalbumin (OVA) and chronically challenged with OVA for 1 mo developed significantly increased levels of eosinophilic inflammation and airway remodeling. In contrast, PI3Kgamma-deficient mice challenged with OVA had significantly reduced numbers of bronchoalveolar lavage and peribronchial eosinophils compared with WT mice. There was no significant difference in the number of bone marrow or circulating peripheral blood eosinophils when comparing WT mice and PI3Kgamma-deficient mice, suggesting that trafficking of eosinophils into the lung was reduced in PI3Kgamma-deficient mice. PI3Kgamma-deficient and WT mice had similar levels of IL-5 and eotaxin-1. The reduced eosinophil recruitment to the airway in PI3Kgamma-deficient mice challenged with OVA was associated with significantly reduced numbers of TGF-beta1+ peribronchial cells, reduced numbers of pSmad 2/3+ airway epithelial cells, and pSmad 2/3+ peribronchial cells, as well as significantly reduced levels of peribronchial fibrosis (quantitated by trichrome staining and image analysis as well as by lung collagen levels). In addition, the area of peribronchial alpha-smooth muscle staining was significantly reduced in PI3Kgamma-deficient compared with WT mice. Overall, this study demonstrates an important role for PI3Kgamma in mediating allergen-induced eosinophilic airway inflammation and airway remodeling, suggesting that PI3Kgamma may be a novel therapeutic target in asthma.
AJP Lung Cellular and Molecular Physiology 12/2008; 296(2):L210-9. · 3.66 Impact Factor
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ABSTRACT: Bronchodilator responses are a hallmark of asthma and a subset of chronic obstructive pulmonary disease (COPD). We evaluated subjects with COPD and computed tomographic (CT) scan evidence of emphysema to determine the biomarker profile associated with a bronchodilator response.
We investigated whether subjects with COPD and a bronchodilator response had increased levels of bronchoalveolar lavage (BAL) fluid eosinophil biomarkers, T(H)2 cytokines, CC chemokines, and serum allergen-specific IgE.
All patients with COPD and control subjects (n = 31) had chest CT scans to detect emphysema and subsequent pulmonary function studies, BAL for biomarkers, and serum IgE measurements.
CT scan score, FEV(1), carbon monoxide single-breath diffusion capacity, and BAL fluid neutrophil biomarker levels were similar in subjects with COPD who had or did not have a bronchodilator response of greater than 12%. In contrast, levels of BAL fluid eosinophil biomarkers (eosinophil cationic protein [ECP] and eotaxin-1) were greater in patients with COPD with a bronchodilator response, whereas T(H)2 cytokines were not detectable in any patients with COPD. BAL fluid ECP and eotaxin-1 levels correlated with CT scan extent of emphysema. Immunostaining of COPD lung sections from a separate cohort of subjects with COPD and healthy subjects demonstrated epithelial expression of eotaxin-1 but no lung expression of IL-4 or IL-5.
Subjects with COPD diagnosed on the basis of the presence of emphysema on CT scan who have a bronchodilator response have increased levels of BAL ECP and eotaxin-1 but not T(H)2 cytokines.
Eosinophil biomarkers (ECP-1 and eotaxin-1) might identify a subset of subjects with COPD with emphysema on CT scans who have a bronchodilator response and an increased extent of emphysema on CT scanning.
The Journal of allergy and clinical immunology 12/2007; 120(5):1118-25. · 9.17 Impact Factor
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ABSTRACT: Intracellular signaling pathways that converge on Smad 3 are used by both TGF-beta and activin A, key cytokines implicated in the process of fibrogenesis. To determine the role of Smad 3 in allergen-induced airway remodeling, Smad 3-deficient and wild-type (WT) mice were sensitized to OVA and challenged by repetitive administration of OVA for 1 mo. Increased levels of activin A and increased numbers of peribronchial TGF-beta1(+) cells were detected in WT and Smad 3-deficient mice following repetitive OVA challenge. Smad 3-deficient mice challenged with OVA had significantly less peribronchial fibrosis (total lung collagen content and trichrome staining), reduced thickness of the peribronchial smooth muscle layer, and reduced epithelial mucus production compared with WT mice. As TGF-beta and Smad 3 signaling are hypothesized to mediate differentiation of fibroblasts to myofibroblasts in vivo, we determined the number of peribronchial myofibroblasts (Col-1(+) and alpha-smooth muscle actin(+)) as assessed by double-label immunofluorescence microscopy. Although the number of peribronchial myofibroblasts increased significantly in WT mice following OVA challenge, there was a significant reduction in the number of peribronchial myofibroblasts in OVA-challenged Smad 3-deficient mice. There was no difference in levels of eosinophilic airway inflammation or airway responsiveness in Smad 3-deficient compared with WT mice. These results suggest that Smad 3 signaling is required for allergen-induced airway remodeling, as well as allergen-induced accumulation of myofibroblasts in the airway. However, Smad 3 signaling does not contribute significantly to airway responsiveness.
The Journal of Immunology 07/2007; 178(11):7310-6. · 5.79 Impact Factor
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ABSTRACT: CD33-related Siglecs (CD33rSiglecs) are a family of sialic acid-recognizing lectins on immune cells whose biologic functions are unknown. We studied in vivo functions of Siglec-F, the CD33rSiglec expressed on mouse eosinophils, which are prominent in allergic processes. Induction of allergic lung inflammation in mice caused up-regulation of Siglec-F on blood and bone marrow eosinophils, accompanied by newly induced expression on some CD4(+) cells, as well as quantitative up-regulation of endogenous Siglec-F ligands in the lung tissue and airways. Taken together with the tyrosine-based inhibitory motif in the cytosolic tail of Siglec-F, the data suggested a negative feedback loop, controlling allergic responses of eosinophils and helper T cells, via Siglec-F and Siglec-F ligands. To pursue this hypothesis, we created Siglec-F-null mice. Allergen-challenged null mice showed increased lung eosinophil infiltration, enhanced bone marrow and blood eosinophilia, delayed resolution of lung eosinophilia, and reduced peribronchial-cell apoptosis. Anti-Siglec-F antibody cross-linking also enhanced eosinophil apoptosis in vitro. These data support the proposed negative feedback role for Siglec-F, represent the first in vivo demonstration of biologic functions for any CD33rSiglec, and predict a role for human Siglec-8 (the isofunctional paralog of mouse Siglec-F) in regulating the pathogenesis of human eosinophil-mediated disorders.
Blood 06/2007; 109(10):4280-7. · 9.90 Impact Factor
