epidermal-growth-factor and Asthma

Amphiregulin is a member of epidermal growth factor family, and is also one of the ligand of epidermal growth factor receptor, it participates in many physiological and pathological process by combining with EGFR. Researches have proved that AREG participates in asthma and airway inflammatory diseases caused by smoking and PM 2.5, and AREG plays an important role in the process of airway remodeling and inflammation. This paper mainly reviews the expression and function of AREG, and focus on it's research status in airway inflammatory disease.

Topics: Airway Remodeling; Amphiregulin; Asthma; Epidermal Growth Factor; ErbB Receptors; Glycoproteins; Humans; Inflammation; Intercellular Signaling Peptides and Proteins; Smoking

Acute and chronic lung inflammation is driven and controlled by several endogenous mediators that undergo proteolytic conversion from surface-expressed proteins to soluble variants by a disintegrin and metalloproteinase (ADAM)-family members. TNF and epidermal growth factor receptor ligands are just some of the many substrates by which these proteases regulate inflammatory or regenerative processes in the lung. ADAM10 and ADAM17 are the most prominent members of this protease family. They are constitutively expressed in most lung cells and, as recent research has shown, are the pivotal shedding enzymes mediating acute lung inflammation in a cell-specific manner. ADAM17 promotes endothelial and epithelial permeability, transendothelial leukocyte migration, and inflammatory mediator production by smooth muscle and epithelial cells. ADAM10 is critical for leukocyte migration and alveolar leukocyte recruitment. ADAM10 also promotes allergic asthma by driving B cell responses. Additionally, ADAM10 acts as a receptor for Staphylococcus aureus (S. aureus) α-toxin and is crucial for bacterial virulence. ADAM8, ADAM9, ADAM15, and ADAM33 are upregulated during acute or chronic lung inflammation, and recent functional or genetic analyses have linked them to disease development. Pharmacological inhibitors that allow us to locally or systemically target and differentiate ADAM-family members in the lung suppress acute and asthmatic inflammatory responses and S. aureus virulence. These promising results encourage further research to develop therapeutic strategies based on selected ADAMs. These studies need also to address the role of the ADAMs in repair and regeneration in the lung to identify further therapeutic opportunities and possible side effects.

Topics: ADAM Proteins; Animals; Asthma; B-Lymphocytes; Bacterial Toxins; Epidermal Growth Factor; Gene Expression Regulation, Enzymologic; Hemolysin Proteins; Humans; Pneumonia, Staphylococcal; Proteolysis; Staphylococcal Infections; Staphylococcus aureus; Transendothelial and Transepithelial Migration; Tumor Necrosis Factor-alpha; Virulence Factors

Asthma remains a severe health problem since current therapies are directed to suppressing, rather than preventing or reversing, the primary disease process. Clearly, a greater understanding of the pathogenesis of asthma is critical to the development of better therapeutic modalities. In this review, we discuss the recent advancements in research targeting the role of airway remodeling in asthma.. Epithelial fragility and abnormalities are being recognized as important facets of asthma, as are other features of remodeling such as angiogenesis, goblet cell hyperplasia and thickened lamina reticularis. Significantly, these anomalies occur early in disease pathogenesis. However, their impact on disease severity remains unclear.. Although an altered immune response is undoubtedly important to the pathogenesis of asthma, there is increasing evidence that the tissue-specific manifestations occur independently of inflammation and significantly impact on disease development and severity.

Topics: ADAM Proteins; alpha Catenin; Animals; Asthma; Epidermal Growth Factor; GABA Modulators; Genetic Therapy; Glucocorticoids; Goblet Cells; Humans; Hyperplasia; Mice; Mucous Membrane; Myocytes, Smooth Muscle; Neovascularization, Pathologic; Respiratory System

Asthma is increasing in prevalence in the developing world, affecting approximately 10% of the world's population. It is characterised by chronic lung inflammation and airway remodelling associated with wheezing, shortness of breath, acute bronchial hyperresponsiveness to a variety of innocuous stimuli and a more rapid decline in lung function over time. Airway remodelling, involving proliferation and differentiation of mesenchymal cells, particularly myofibroblasts and smooth muscle cells, is generally refractory to corticosteroids and makes a major contribution to disease chronicity. Transforming growth factor-beta is a potent profibrogenic factor whose expression is increased in the asthmatic airways and is a prime candidate for the initiation and persistence of airway remodelling in asthma. This review highlights the role of transforming growth factor-beta in the asthmatic lung, incorporating biosynthesis, signalling pathways and functional outcome. In vivo, however, it is the balance between transforming growth factor-beta and other growth factors, such as epidermal growth factor, which will determine the extent of fibrosis in the airways. A fuller comprehension of the actions of transforming growth factor-beta, and its interaction with other signalling pathways, such as the epidermal growth factor receptor signalling cascade, may enable development of therapies that control airway remodelling where there is an unmet clinical need.

Topics: Asthma; Chronic Disease; Epidermal Growth Factor; Epithelial Cells; Extracellular Matrix; Humans; Microscopy, Electron; Signal Transduction; Transforming Growth Factor beta

Lysophosphatidic acid (LPA) is a bioactive lipid mediator and important component of serum. Studies over the past several years which have documented diverse effects of LPA on multiple types of airway cells and which suggest possible involvement of LPA in lung disease are reviewed here. LPA enhances contractility of airway smooth muscle. It also stimulates proliferation of cultured airway smooth muscle cells and exhibits a striking synergism with epidermal growth factor (EGF) for stimulating mitogenesis. Recent studies of the molecular components and signaling pathways mediating synergism are described, including LPA-induced upregulation of EGF receptors and activation of multiple transcription factors by both LPA and EGF. A model for the effects of LPA and EGF on mitogenesis that includes EGF receptor upregulation and synergism between Ras and Rho for activation of the transcription factor AP-1 is presented. LPA stimulates fibronectin secretion and filopodia extension in airway epithelial cells as well as proliferation and collagen gel contraction by lung fibroblasts. A hypothesis for LPA involvement in the airway repair and remodeling, which contribute to the pathology of asthma and other airway diseases, is presented, and future directions for research into the roles of LPA in airway function and disease are suggested.

Topics: Animals; Asthma; Cell Division; Epidermal Growth Factor; Humans; Lysophospholipids; MAP Kinase Signaling System; Respiratory Mucosa; Respiratory Physiological Phenomena; Respiratory Tract Diseases; Signal Transduction

Topics: Asthma; Bronchi; Chronic Disease; Epidermal Growth Factor; Epithelium; Fibrosis; Humans; Models, Immunological; Signal Transduction

Infection with rhinovirus (RV) is a major risk factor for disease exacerbations in patients with allergic asthma. This study analysed a broad set of cytokines in the noses of children and adults with asthma during RV infection in order to identify immunophenotypes that may link to virus-induced episodes.. Nasal wash specimens were analysed in children (n = 279 [healthy, n = 125; stable asthma, n = 64; wheeze, n = 90], ages 2-12) who presented to a hospital emergency department, and in adults (n = 44 [healthy, n = 13; asthma, n = 31], ages 18-38) who were experimentally infected with RV, including a subset who received anti-IgE. Cytokines were measured by multiplex bead assay and data analysed by univariate and multivariate methods to test relationships to viral load, allergic status, airway inflammation, and clinical outcomes.. Analysis of a core set of 7 cytokines (IL-6, CXCL8/IL-8, IL-15, EGF, G-CSF, CXCL10/IP-10 and CCL22/MDC) revealed higher levels in children with acute wheeze versus those with stable asthma or controls. Multivariate analysis identified two clusters that were enriched for acutely wheezing children; one displaying high viral load ("RV-high") with robust secretion of CXCL10, and the other displaying high IgE with elevated EGF, CXCL8 and both eosinophil- and neutrophil-derived mediators. Broader assessment of 39 cytokines confirmed that children with acute wheeze were not deficient in type 1 anti-viral responses. Analysis of 18 nasal cytokines in adults with asthma who received RV challenge identified two clusters; one that was "RV-high" and linked to robust induction of anti-viral cytokines and anti-IgE; and the other associated with more severe symptoms and a higher inflammatory state featuring eosinophil and neutrophil factors.. The results confirm the presence of different immunophenotypes linked to parameters of airway disease in both children and adults with asthma who are infected with RV. Such discrepancies may reflect the ability to regulate anti-viral responses.

Topics: Adolescent; Adult; Asthma; Chemokine CXCL10; Child; Child, Preschool; Cluster Analysis; Cytokines; Enterovirus Infections; Epidermal Growth Factor; Granulocyte Colony-Stimulating Factor; Humans; Interleukin-15; Interleukin-6; Interleukin-8; Picornaviridae Infections; Respiratory Sounds; Rhinovirus; Young Adult

Decreased exposure to microbial agents in industrialized countries and urban living areas is considered as a risk factor of developing immune-mediated diseases, such as allergies and asthma. Epithelial surfaces in the gastrointestinal and respiratory tracts and in the skin constitute the primary areas in contact with the environmental microbial load.. We analyzed the levels of 30 cytokines and growth factors in serum or plasma as markers of the immune maturation in the participants in the DIABIMMUNE study from Russian Karelia (n = 60), Estonia (n = 83) and Finland (n = 89), three neighboring countries with remarkable differences in the incidences of allergies, asthma and autoimmune diseases.. We observed an upregulation of T helper cell signature cytokines during the first 12 months of life, reflecting natural development of adaptive immune responses. During the first years of life, circulating concentrations of epidermal growth factor (EGF) were significantly higher, especially in Russian children compared with Finnish children. The children who developed IgE sensitization showed lower levels of EGF than those without such responses.. Our results suggest that low circulating EGF levels associate with the risk of allergies possibly via the effects on the epithelial integrity and mucosal homeostasis.

Topics: Allergens; Asthma; Child; Child, Preschool; Epidermal Growth Factor; Humans; Hypersensitivity; Immunoglobulin E

Limited in vivo models exist to investigate the lung airway epithelial role in repair, regeneration, and pathology of chronic lung diseases. Herein, we introduce a novel animal model in asthma-a xenograft system integrating a differentiating human asthmatic airway epithelium with an actively remodeling rodent mesenchyme in an immunocompromised murine host. Human asthmatic and nonasthmatic airway epithelial cells were seeded into decellularized rat tracheas. Tracheas were ligated to a sterile cassette and implanted subcutaneously in the flanks of nude mice. Grafts were harvested at 2, 4, or 6 weeks for tissue histology, fibrillar collagen, and transforming growth factor-β activation analysis. We compared immunostaining in these xenografts to human lungs. Grafted epithelial cells generated a differentiated epithelium containing basal, ciliated, and mucus-expressing cells. By 4 weeks postengraftment, asthmatic epithelia showed decreased numbers of ciliated cells and decreased E-cadherin expression compared with nonasthmatic grafts, similar to human lungs. Grafts seeded with asthmatic epithelial cells had three times more fibrillar collagen and induction of transforming growth factor-β isoforms at 6 weeks postengraftment compared with nonasthmatic grafts. Asthmatic epithelium alone is sufficient to drive aberrant mesenchymal remodeling with fibrillar collagen deposition in asthmatic xenografts. Moreover, this xenograft system represents an advance over current asthma models in that it permits direct assessment of the epithelial-mesenchymal trophic unit.

Topics: Adult; Airway Remodeling; Animals; Asthma; Demography; Disease Models, Animal; Epidermal Growth Factor; Extracellular Matrix; Female; Heterografts; Humans; Lung; Male; Middle Aged; Pulmonary Fibrosis; Rats, Inbred F344; Signal Transduction; Tissue Donors; Transforming Growth Factor beta1; Young Adult

The T-helper cell type 2-promoting cytokine interleukin-33 (IL-33) has been implicated in asthma pathogenesis. Angiogenesis is a feature of airways remodelling in asthma. We hypothesized that IL-33 induces airways angiogenesis and expression of angiogenic factors in an established murine surrogate of asthma. In the present study, BALB/c mice were subjected to serial intranasal challenge with IL-33 alone for up to 70 days. In parallel, ovalbumin (OVA) -sensitized mice were subjected to serial intranasal challenge with OVA or normal saline to serve as positive and negative controls, respectively. Immunohistochemical analysis of expression of von Willebrand factor and erythroblast transformation-specific-related gene, both blood vessel markers, and angiogenic factors angiogenin, insulin-like growth factor-1, endothelin-1, epidermal growth factor and amphiregulin was performed in lung sections ex vivo. An established in-house assay was used to test whether IL-33 was able to induce microvessel formation by human vascular endothelial cells. Results showed that serial intranasal challenge of mice with IL-33 or OVA resulted in proliferation of peribronchial von Willebrand factor-positive blood vessels to a degree closely related to the total expression of the angiogenic factors amphiregulin, angiogenin, endothelin-1, epidermal growth factor and insulin-like growth factor-1. IL-33 also induced microvessel formation by human endothelial cells in a concentration-dependent fashion in vitro. Our data are consistent with the hypothesis that IL-33 has the capacity to induce angiogenesis at least partly by increasing local expression of multiple angiogenic factors in an allergen-independent murine asthma surrogate, and consequently that IL-33 or its receptor is a potential novel molecular target for asthma therapy.

Topics: Administration, Intranasal; Angiogenesis Inducing Agents; Animals; Asthma; Epidermal Growth Factor; Female; Interleukin-33; Lung; Mice; Mice, Inbred BALB C; Neovascularization, Physiologic

Airway remodeling is known to be a consequence of repeated injury and thought to be involved in early stage of asthma. We aimed to investigate the mediators associated with airway remodeling in recurrent early wheezers. Thirty-three infants, aged 2 years or less, admitted with exacerbation of wheezing were enrolled. All of them had experienced three or more episodes of wheezing before admission. They were categorized into two groups: those who had been hospitalized two or more times for severe wheezing (N = 19) and those who had only once or never been hospitalized (N = 14). Epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-β1 levels in nasopharyngeal aspirates (NPA) collected on admission were measured. The difference between two patients groups divided based on their hospitalization history was assessed. We also examined these mediators in older asthmatic children (N = 15) admitted with exacerbation and their relationship with lung function parameters measured after stabilization. NPA EGF levels were significantly increased in recurrent early wheezers compared to controls. EGF, VEGF, and TGF-β1 levels were significantly higher in those with a previous history of multiple hospitalizations than in those without. In older asthmatic children, EGF levels were related with age and duration of asthma, but showed an inverse correlation with forced expiratory volume in 1 sec and forced expiratory flow between 25% and 75% of vital capacity. Our study shows that there might be significant damage during exacerbation in wheezy infants as levels of the mediators, EGF, VEGF, and TGF-β1 were higher in those who had been frequently hospitalized. It seems to suggest that those infants with severe recurrent wheezing might have chronic airway obstruction.

Topics: Age Factors; Asthma; Case-Control Studies; Child, Preschool; Epidermal Growth Factor; Female; Forced Expiratory Flow Rates; Forced Expiratory Volume; Hospitalization; Humans; Infant; Male; Nasal Cavity; Pharynx; Recurrence; Respiratory Sounds; Transforming Growth Factor beta1; Vascular Endothelial Growth Factor A

Epithelial remodelling in asthma is characterised by goblet cell hyperplasia and mucus hypersecretion for which no therapies exist. Differentiated bronchial air-liquid interface cultures from asthmatic children display high goblet cell numbers. Epidermal growth factor and its receptor have been implicated in goblet cell hyperplasia.. We hypothesised that EGF removal or tyrphostin AG1478 treatment of differentiating air-liquid interface cultures from asthmatic children would result in a reduction of epithelial goblet cells and mucus secretion.. In Aim 1 primary bronchial epithelial cells from non-asthmatic (n = 5) and asthmatic (n = 5) children were differentiated under EGF-positive (10 ng/ml EGF) and EGF-negative culture conditions for 28 days. In Aim 2, cultures from a further group of asthmatic children (n = 5) were grown under tyrphostin AG1478, a tyrosine kinase inhibitor, conditions. All cultures were analysed for epithelial resistance, markers of differentiation using immunocytochemistry, ELISA for MUC5AC mucin secretion and qPCR for MUC5AC mRNA.. In cultures from asthmatic children the goblet cell number was reduced in the EGF negative group (p = 0.01). Tyrphostin AG1478 treatment of cultures from asthmatic children had significant reductions in goblet cells at 0.2 μg/ml (p = 0.03) and 2 μg/ml (p = 0.003) as well as mucus secretion at 2 μg/ml (p = 0.04).. We have shown in this preliminary study that through EGF removal and tyrphostin AG1478 treatment the goblet cell number and mucus hypersecretion in differentiating air-liquid interface cultures from asthmatic children is significantly reduced. This further highlights the epidermal growth factor receptor as a potential therapeutic target to inhibit goblet cell hyperplasia and mucus hypersecretion in asthma.

Topics: Adolescent; Air; Asthma; Bronchi; Cell Count; Cell Differentiation; Cell Proliferation; Cells, Cultured; Child; Child, Preschool; Electric Impedance; Epidermal Growth Factor; Female; Goblet Cells; Humans; Infant; Male; Models, Biological; Mucin 5AC; Quinazolines; RNA, Messenger; Tyrphostins

Topics: Adrenal Cortex Hormones; Adrenergic alpha-2 Receptor Agonists; Adult; Aged; Aged, 80 and over; Airway Obstruction; Airway Remodeling; Asthma; Chronic Disease; Elasticity; Epidermal Growth Factor; Female; Follow-Up Studies; Humans; Leukotriene Antagonists; Lung; Male; Middle Aged; Muscarinic Antagonists; Prospective Studies; Pulmonary Emphysema; Radiography

Epidemiologic studies suggest that increased concentrations of airborne spores of Aspergillus fumigatus closely relate to asthma aggravation. Chronic exposure to A. fumigatus aggravates airway inflammation, remodeling, and airway hyperresponsiveness in asthmatic rats. The effects of chronic exposure to A. fumigatus on epidermal growth factor receptor (EGFR) expression in the airway epithelial cells of asthmatic rats remain unclear. This study aimed to investigate the effects of chronic exposure to A. fumigatus on injury and shedding of airway epithelium, goblet cell metaplasia, and EGFR expression in the airway epithelial cells of asthmatic rats. A rat model of chronic asthma was established using ovalbumin (OVA) sensitization and challenge. Rats with chronic asthma were then exposed to long-term inhalation of spores of A. fumigatus, and the dynamic changes in injury and shedding of airway epithelium, goblet cell metaplasia, and EGFR expression were observed and analyzed. Chronic exposure to A. fumigatus could aggravate airway epithelial cell damage, upregulate the expression of EGFR and its ligands EGF and TGF-α, promote goblet cell metaplasia, and increase airway responsiveness in rats with asthma. Chronic exposure to A. fumigatus upregulates the expression of EGFR and its ligands in asthmatic rats. The EGFR pathway may play a role in asthma aggravation induced by exposure to A. fumigatus.

Topics: Animals; Aspergillosis; Aspergillus fumigatus; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Epidermal Growth Factor; Epithelial Cells; ErbB Receptors; Goblet Cells; Male; Metaplasia; Ovalbumin; Pneumonia; Rats; Rats, Wistar

The molecular basis for airway epithelial fragility in asthma has remained unclear. We investigated whether the loss of caveolin-1, the major component of caveolae and a known stabilizer of adherens junctions, contributes to epithelial barrier dysfunction in asthma. We studied the expression of caveolin-1 and adhesion molecules E-cadherin and β-catenin in airway sections, and we cultured bronchial epithelial cells from patients with asthma and from healthy control subjects. To determine the functional role of caveolin-1, we investigated the effects of caveolin-1 up-regulation and down-regulation on E-cadherin expression, barrier function, and proallergic activity in the human bronchial epithelial cell lines 16HBE and BEAS-2B. The membrane expression of caveolin-1 was significantly lower in airway epithelia from patients with asthma than from subjects without asthma, and this lower expression was maintained in vitro upon air-liquid interface and submerged culturing. Importantly, reduced caveolin-1 expression was accompanied by a loss of junctional E-cadherin and β-catenin expression, disrupted epithelial barrier function, and increased levels of the proallergic cytokine thymic stromal lymphopoietin (TSLP). Furthermore, E-cadherin redistribution upon exposure to epidermal growth factor or house dust mite was paralleled by the internalization of caveolin-1 in 16HBE cells. These effects appear to be causally related, because the short, interfering RNA down-regulation of caveolin-1 resulted in the delocalization of E-cadherin and barrier dysfunction in 16HBE cells. Moreover, caveolin-1 overexpression improved barrier function and reduced TSLP expression in BEAS-2B cells. Together, our data demonstrate a crucial role for caveolin-1 in epithelial cell-cell adhesion, with important consequences for epithelial barrier function and the promotion of Th2 responses in asthma.

Topics: Adherens Junctions; Adolescent; Adult; Animals; Asthma; beta Catenin; Bronchi; Cadherins; Caveolin 1; Cell Adhesion; Cell Adhesion Molecules; Child; Down-Regulation; Epidermal Growth Factor; Epithelial Cells; Female; Humans; Male; Pyroglyphidae; Respiratory Mucosa; Th2 Cells; Up-Regulation

Chronic damage and repair of the bronchial epithelium are features of asthma. We have previously reported that ex vivo stimulation of normal bronchial epithelial cells with epidermal growth factor (EGF), a key factor of epithelial repair, enhances the mechanisms of neutrophil accumulation, thereby promoting neutrophil defences during acute injury but potentially enhancing inflammation in chronic airway diseases. We have now sought to (i) determine whether this EGF-dependent pro-neutrophil activity is increased in asthma, where EGF and its epithelial receptor are over-expressed, and (ii) elucidate some of the mechanisms underlying this asthmatic epithelial-neutrophil interaction. Primary bronchial epithelial cells (PBEC) from healthy subjects, mild asthmatics and moderate-to-severe asthmatics (Mod/Sev) were stimulated with EGF, a model that mimics a repairing epithelium. Conditioned culture media (EGF-CM) were assessed for neutrophil chemotactic and anti-apoptotic activities and inflammatory mediator production. EGF induced the epithelium to produce soluble mediators with neutrophil chemotactic (p<0.001) and pro-survival (p = 0.021) activities which were related to the clinical severity of asthma (trend p = 0.010 and p = 0.009, respectively). This was associated with enhanced IL-6, IL-8, GM-CSF and TNF-α release, and cytokine-neutralising experiments using EGF-CM from Mod/Sev asthmatics demonstrated a role for GM-CSF in neutrophil survival (p<0.001). Pre-treatment of neutrophils with specific inhibitors of the myeloid-restricted class I phosphatidylinositol-3-OH kinase (PI(3)K) isoforms showed that the EGF-CM from Mod/Sev asthmatics depended on the γ (p<0.021) but not δ isoforms, while neutrophil survival required multiple class I PI(3)Ks. The EGF-induced chemotactic, but not pro-survival activity, involved RhoA signaling in neutrophils (p = 0.012). EGF whose activity is upregulated in asthma induces ex vivo the epithelium from asthmatic patients to produce pro-neutrophil activities; these are related to asthma severity and, in moderate-to-severe asthmatics, involves class IB PI(3)Kγ signaling, providing a potential therapeutic target for neutrophilic forms of asthma.

Topics: Adult; Apoptosis; Asthma; Bronchi; Case-Control Studies; Cell Proliferation; Cells, Cultured; Chemokines; Chemotaxis, Leukocyte; Culture Media, Conditioned; Epidermal Growth Factor; Epithelial Cells; Female; Humans; Male; Middle Aged; Neutrophils; Phosphatidylinositol 3-Kinases; Respiratory Mucosa; rhoA GTP-Binding Protein

Though implicated in vascular remodelling, a role for the resistin-like molecule (RELM)-β in human airway remodelling remains unexplored. We hypothesised that RELM-β expression is increased in the airways of asthmatics and regulates airways epithelial cell function. Expression of RELM-β in the bronchial mucosa and its concentrations in bronchoalveolar lavage (BAL) fluid from asthmatics and controls were measured by immunohistochemistry and ELISA, respectively. Proliferation assays, Western blotting, ELISA and real-time PCR were employed to detect effects of RELM-β on airways epithelial cells. RELM-β expression was increased in the bronchial mucosa and BAL fluid of asthmatics compared with controls. In the asthmatics, the numbers of mucosal RELM-β+ cells correlated inversely with forced expiratory volume in 1 s (r=-0.531, p=0.016), while the numbers of epithelial RELM-β+ cells correlated positively with those of mucin (MUC)5AC+ cells. In vitro, interleukin-13 enhanced RELM-β expression by primary human airways epithelial cells, while RELM-β itself acted on these cells to induce proliferation, expression of MUC5AC, extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-phosphatidylinositol 3-kinase (PI3K)/Akt phosphorylation and elevated expression of transforming growth factor-β2, epidermal growth factor and vascular endothelial growth factor. RELM-β has the potential to contribute to airway remodelling in diseases such as asthma by acting on epithelial cells to increase proliferation, mucin and growth factor production, at least partly via ERK/MAPK-PI3K/Akt signalling pathways.

Topics: Adult; Asthma; Bronchoalveolar Lavage Fluid; Cell Division; Cells, Cultured; Epidermal Growth Factor; Extracellular Signal-Regulated MAP Kinases; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Mucin 5AC; Phosphatidylinositol 3-Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Respiratory Mucosa; RNA, Messenger; Transforming Growth Factor beta1; Transforming Growth Factor beta2; Vascular Endothelial Growth Factor A

Exposure to particulate matter (PM) is associated with adverse pulmonary effects, including induction and exacerbation of asthma. Recently arginase was shown to play an important role in the pathogenesis of asthma. In this study, it was postulated that PM exposure might induce arginase. Human bronchial epithelial cells (HBEC) obtained from normal individuals by endobronchial brushings cultured on an air-liquid interface were incubated with fine Chapel Hill particles (PM₂.₅, 100 μg/ml) for up to 72 h. Arginase activity, protein expression, and mRNA of arginase I and arginase II were measured. PM₂.₅ increased arginase activity in a time-dependent manner. The rise was primarily due to upregulation of arginase II. PD153035 (10 μM), an epidermal growth factor (EGF) receptor antagonist, attenuated the PM₂.₅-induced elevation in arginase activity and arginase II expression. Treatment of HBEC with human EGF increased arginase activity and arginase II expression. Pretreatment with catalase (200 U/ml), superoxide dismutase (100 U/ml), or apocynin (5 μg/ml), an NAD(P)H oxidase inhibitor, did not markedly affect arginase II expression. Treatment of HBEC with arginase II siRNA inhibited the expression of arginase II by 60% and increased IL-8 release induced by PM₂.₅. These results indicate that PM exposure upregulates arginase II activity and expression in human bronchial epithelial cells, in part via EGF-dependent mechanisms independent of oxidative stress. The elevated arginase II activity and expression may be a mechanism underlying adverse effects induced by PM exposure in asthma patients.

Topics: Air Pollutants; Arginase; Asthma; Bronchi; Cells, Cultured; Enzyme Induction; Epidermal Growth Factor; ErbB Receptors; Humans; Interleukin-8; Isoenzymes; North Carolina; Particulate Matter; Recombinant Proteins; Respiratory Mucosa; RNA Interference; RNA, Messenger; RNA, Small Interfering; Time Factors

Phosphoinositide 3-kinase (PI3K)/Akt pathway is linked to the development of asthma. Anti-malarial drug artesunate is a semi-synthetic derivative of artemisinin, the principal active component of a medicinal plant Artemisia annua, and has been shown to inhibit PI3K/Akt activity. We hypothesized that artesunate may attenuate allergic asthma via inhibition of the PI3K/Akt signaling pathway.. Female BALB/c mice sensitized and challenged with ovalbumin (OVA) developed airway inflammation. Bronchoalveolar lavage fluid was assessed for total and differential cell counts, and cytokine and chemokine levels. Lung tissues were examined for cell infiltration and mucus hypersecretion, and the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Artesunate dose-dependently inhibited OVA-induced increases in total and eosinophil counts, IL-4, IL-5, IL-13 and eotaxin levels in bronchoalveolar lavage fluid. It attenuated OVA-induced lung tissue eosinophilia and airway mucus production, mRNA expression of E-selectin, IL-17, IL-33 and Muc5ac in lung tissues, and airway hyperresponsiveness to methacholine. In normal human bronchial epithelial cells, artesunate blocked epidermal growth factor-induced phosphorylation of Akt and its downstream substrates tuberin, p70S6 kinase and 4E-binding protein 1, and transactivation of NF-κB. Similarly, artesunate blocked the phosphorylation of Akt and its downstream substrates in lung tissues from OVA-challenged mice. Anti-inflammatory effect of artesunate was further confirmed in a house dust mite mouse asthma model.. Artesunate ameliorates experimental allergic airway inflammation probably via negative regulation of PI3K/Akt pathway and the downstream NF-κB activity. These findings provide a novel therapeutic value for artesunate in the treatment of allergic asthma.

Topics: Animals; Anti-Inflammatory Agents; Antimalarials; Artemisinins; Artesunate; Asthma; Bronchi; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Enzyme Activation; Epidermal Growth Factor; Epithelial Cells; Female; Gene Expression Regulation; Humans; Hypersensitivity; Mice; Mice, Inbred BALB C; Mucus; Ovalbumin; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Pyroglyphidae; Signal Transduction; Th2 Cells

Asthma is a complex disease involving gene and environment interactions. Although atopy is a strong predisposing risk factor for asthma, local tissue susceptibilities are required for disease expression. The bronchial epithelium forms the interface with the external environment and is pivotally involved in controlling tissue homeostasis through provision of a physical barrier controlled by tight junction (TJ) complexes.. To explain the link between environment exposures and airway vulnerability, we hypothesized that epithelial TJs are abnormal in asthma, leading to increased susceptibility to environmental agents.. Localization of TJs in bronchial biopsies and differentiated epithelial cultures was assessed by electron microscopy or immunostaining. Baseline permeability and the effect of cigarette smoke and growth factor were assessed by measurement of transepithelial electrical resistance and passage of fluorescently labeled dextrans.. By using immunostaining, we found that bronchial biopsies from asthmatic subjects displayed patchy disruption of TJs. In differentiated bronchial epithelial cultures, TJ formation and transepithelial electrical resistance were significantly lower (P < .05) in cultures from asthmatic donors (n = 43) than from normal controls (n = 40) and inversely correlated with macromolecular permeability. Cultures from asthmatic donors were also more sensitive to disruption by cigarette smoke extract. Epidermal growth factor enhanced basal TJ formation in cultures from asthmatic subjects (P < .01) and protected against cigarette smoke-induced barrier disruption (P < .01).. Our results show that the bronchial epithelial barrier in asthma is compromised. This defect may facilitate the passage of allergens and other agents into the airway tissue, leading to immune activation and may thus contribute to the end organ expression of asthma.

Topics: Animals; Asthma; Biopsy; Bronchi; Cell Membrane Permeability; Cells, Cultured; Dextrans; Epidermal Growth Factor; Epithelial Cells; Humans; Mice; Microscopy, Electron; Nicotiana; Smoking; Tight Junctions

Severe asthma is characterized by increased airway smooth muscle (ASM) mass due, in part, to ASM cell growth and contractile protein expression associated with increased protein synthesis. Little is known regarding the combined effects of mitogens and interferons on ASM cytosolic protein synthesis. We demonstrate that human ASM mitogens including PDGF, EGF, and thrombin stimulate protein synthesis. Surprisingly, pleiotropic cytokines IFN-beta and IFN-gamma, which inhibit ASM proliferation, also increased cytosolic protein content in ASM cells. Thus IFN-beta alone significantly increased protein synthesis by 1.62 +/- 0.09-fold that was further enhanced by EGF to 2.52 +/- 0.17-fold. IFN-gamma alone also stimulated protein synthesis by 1.91 +/- 0.15-fold; treatment of cells with PDGF, EGF, and thrombin in the presence of IFN-gamma stimulated protein synthesis by 2.24 +/- 0.3-, 1.25 +/- 0.17-, and 2.67 +/- 0.34-fold, respectively, compared with growth factors alone. The mammalian target of rapamycin (mTOR)/S6 kinase 1 (S6K1) inhibition with rapamycin inhibited IFN- and EGF-induced protein synthesis, suggesting that IFN-induced protein synthesis is modulated by mTOR/S6K1 activation. Furthermore, overexpression of tumor suppressor protein tuberous sclerosis complex 2 (TSC2), which is an upstream negative regulator of mTOR/S6K1 signaling, also inhibited mitogen-induced protein synthesis in ASM cells. IFN-beta and IFN-gamma stimulated miR143/145 microRNA expression and increased SM alpha-actin accumulation but had little effect on ASM cell size. In contrast, EGF increased ASM cell size but had little effect on miR143/145 expression. Our data demonstrate that both IFNs and mitogens stimulate protein synthesis but have differential effects on cell size and contractile protein expression and suggest that combined effects of IFNs and mitogens may contribute to ASM cell growth, contractile protein expression, and ASM remodeling in asthma.

Topics: Animals; Asthma; Cells, Cultured; Epidermal Growth Factor; Humans; Interferons; Intracellular Signaling Peptides and Proteins; Mitogens; Muscle, Smooth; Platelet-Derived Growth Factor; Protein Biosynthesis; Protein Serine-Threonine Kinases; Respiratory System; Ribosomal Protein S6 Kinases; Signal Transduction; Thrombin; TOR Serine-Threonine Kinases

Epidermal growth factor receptor ligands, such as epidermal growth factor (EGF) and amphiregulin, may play key roles in tissue remodeling in asthma. However, the kinetics of EGF and amphiregulin secretion in the airway after an acute asthma attack and the effect of prolonged airway exposure to these ligands on airway remodeling are unknown.. To measure the EGF and amphiregulin concentrations in sputa obtained from patients with asthma under various conditions, and to examine the effects of EGF and amphiregulin on the proliferation or differentiation of airway structural cells.. Epidermal growth factor and amphiregulin levels were measured by ELISA in sputum specimens collected from 14 hospitalized children with asthma during an acute asthma attack, 13 stable outpatients with asthma, 8 healthy control children, and 7 children with respiratory tract infections. The effects of EGF and amphiregulin on the proliferation and/or differentiation of normal human bronchial epithelial cells (NHBE), bronchial smooth muscle cells (BSMC), and normal human lung fibroblasts (NHLF) were examined.. The sputum levels of EGF were significantly higher for about a week after an acute asthma attack compared with the levels in stable subjects with asthma and control subjects. In contrast, upregulation of amphiregulin in the sputa of patients with asthma was observed only during the acute attack. EGF caused proliferation of NHBE, BSMC, and NHLF, whereas amphiregulin induced proliferation of only NHBE. Prolonged exposure of NHBE to EGF and amphiregulin induced mucous cell metaplasia in an IL-13-independent manner.. Acute asthma attacks are associated with hypersecretion of EGF and amphiregulin in the airway. Recurrent acute attacks may aggravate airway remodeling.

Topics: Acute Disease; Adolescent; Amphiregulin; Asthma; Cell Line; Cell Proliferation; Cells, Cultured; Child; Child, Preschool; EGF Family of Proteins; Epidermal Growth Factor; Epithelial Cells; Extracellular Signal-Regulated MAP Kinases; Female; Fibroblasts; Glycoproteins; Humans; Infant; Infant, Newborn; Intercellular Signaling Peptides and Proteins; Male; Mucin 5AC; Myocytes, Smooth Muscle; Phosphorylation; Proto-Oncogene Proteins c-fos; Recombinant Proteins; Respiratory Mucosa; Signal Transduction; Sputum

Epithelial damage is an important pathophysiologic feature of asthma. Bronchial epithelium damage results in release of growth factors such as transforming growth factor (TGF)-beta(1) that may affect epithelial cell proliferation. The objective of our study is to evaluate the importance of TGF-beta(1) in regulating epithelial cell repair in asthma. We evaluated the effect of TGF-beta(1) on epidermal growth factor (EGF)-induced proliferation and downstream signaling in epithelial cells obtained from subjects with asthma compared with cells from healthy subjects. Cell proliferation was evaluated by bromodeoxyuridine incorporation. EGF receptor (EGFR), mitogen-activated protein kinase, TGF-beta receptors, Smads, Smad anchor for receptor activation (SARA), and cyclin-dependant kinase inhibitors were evaluated by Western blot. TGF-beta(1) and receptor expression were measured by RT-PCR and by enzyme-linked immunosorbent assay. Proliferation of epithelial cells at baseline and after EGF stimulation was significantly reduced in cells derived from subjects with asthma compared with cells obtained from healthy control subjects. EGF-induced ERK1/2 phosphorylation was reduced in epithelial cells from subjects with asthma compared with cells from healthy control subjects. This was paralleled with a reduced EGFR phosphorylation. Addition of TGF-beta(1) significantly decreased EGF-induced cell proliferation. TGF-beta(1) production was higher in asthmatic epithelial cells compared with normal cells. This was supported by a high expression of pSmad 3 and SARA in cells derived from individuals with asthma compared with normal subjects. Cycline-dependent kinase inhibitors were highly expressed in asthmatic compared with normal cells. Inhibition of TGF-beta(1) signaling in asthmatic epithelial cells restored EGFR, ERK1/2 phosphorylation, and cell proliferation induced by EGF. Our results suggest that TGF-beta restrains EGFR phosphorylation and downstream signaling in bronchial epithelial cells.

Topics: Asthma; Base Sequence; Blotting, Western; Case-Control Studies; Cell Proliferation; DNA Primers; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Epithelial Cells; Humans; MAP Kinase Signaling System; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta

The pathogenesis of asthma involves a combination of genetic and environmental factors. The epidemiology studies have shown that SO(2)might play an important role in the initiation or exacerbation of the asthma disease. To investigate the asthmatic molecular mechanisms exposed to SO(2), male Wistar rats were divided randomly into four equal groups of six animals each: (1) SO(2) group, (2) ovalbumin (OVA) group (asthma group), (3) SO(2)plus OVA group, and (4) control group. The rats were challenged by ovalbumin (OVA) or SO(2) (5.6 mg/m(3)) inhalation alone or together. The mRNA and protein levels of asthma-related genes (EGF, EGFR, and COX-2) were analyzed in lungs and tracheas using real-time reverse transcription-polymerase chain reaction assay, radioimmunoassay method, and Western blot analysis, respectively. The results showed that inhaled SO(2) alone increased the mRNA and protein expressions of three tested genes in lung and trachea tissues, but only the mRNA levels of EGFR and COX-2 in tracheas were significantly increased compared with the control. However, OVA exposure significantly induced the mRNA and protein expressions of EGF, EGFR, and COX-2 compared with the control. Meanwhile, OVA plus SO(2) inhalation enhanced the mRNA and protein levels of these genes in rat airways, versus exposure to OVA alone. These results suggested that SO(2) could increase the expressions of EGF, EGFR, and COX-2 on the transcription and translation levels in the lungs and tracheas from asthmatic rats, which might be one of the possible mechanisms by which SO(2) pollution aggravates asthma disease.

Topics: Air Pollutants; Animals; Asthma; Cyclooxygenase 2; Disease Models, Animal; Drug Synergism; Epidermal Growth Factor; ErbB Receptors; Gene Expression Regulation; Inhalation Exposure; Lung; Male; Ovalbumin; Rats; Rats, Wistar; RNA, Messenger; Sulfur Dioxide; Trachea

Interleukin-31 (IL-31) is a novel T-helper-lymphocyte-derived cytokine that plays an important role in allergic skin inflammation and atopic dermatitis. It has recently been implicated in bronchial inflammation. We investigated the functions and mechanisms of IL-31-induced activation of human bronchial epithelial cells. The gene and protein expressions of candidate cytokines/chemokines from IL-31-stimulated human bronchial epithelial BEAS-2B cells were first quantified by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The activity of different mitogen-activated protein kinases (MAPKs) in IL-31-stimulated BEAS-2B cells was assessed by Western blot. The IL-31 could significantly elevate the gene and protein expressions of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein-1 (MCP-1/CCL2) of BEAS-2B cells in both time-dependently and dose-dependently. Combination of IL-31 with either IL-4 or IL-13 further enhanced VEGF and CCL2 production while IL-31 could synergistically augment the release of EGF, VEGF, CCL2, IL-6 and IL-8 in cocultures of BEAS-2B cells and eosinophils. In addition, IL-31 could activate p38 MAPK, extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) of BEAS-2B cells. Selective inhibitors of p38 MAPK (SB203580), ERK (PD98059), and JNK (SP600125) could differentially inhibit the production of EGF, VEGF and CCL2, thereby suggesting a role for MAPKs in IL-31 functions. In conclusion, the activation of MAPKs can be crucial for IL-31-mediated activation of bronchial epithelial cells, thereby providing an immunological role for IL-31 in bronchial inflammation, at least partly, via epithelial EGF, VEGF and CCL2 production.

Topics: Asthma; Bronchi; Cells, Cultured; Chemokine CCL2; Chemokines; Cytokines; Epidermal Growth Factor; Epithelial Cells; Humans; Interleukin-13; Interleukin-4; Interleukins; MAP Kinase Signaling System; Mitogen-Activated Protein Kinases; Receptors, Interleukin; Vascular Endothelial Growth Factor A

Sulfur dioxide (SO(2)) is a common air pollutant, and inhaled SO(2) in airway epithelium easily forms its soluble derivatives in vivo (bisulfite and sulfite), which are toxic to the respiratory system and related to the exacerbation of asthma. In order to study the possible asthmatic molecular mechanism of SO(2) and its derivatives, the dose-response and time-response relationships of SO(2) derivatives on gene expressions of some asthma-related genes in human bronchial epithelial cells (BEP2D) were investigated. The mRNA and protein levels of EGF, EGFR, ICAM-1 and COX-2 were analyzed in BEP2D cells using real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) assay, radio-immunoassay (RIA) method and Western blot analysis, respectively. The results showed that SO(2) derivatives caused the dose-dependent inductive expressions of four gene mRNA and protein in BEP2D cells. Moreover, SO(2) derivatives significantly increased the mRNA and protein levels at 0, 0.5, 1, 4 and 24h post-exposure, along with the highest inductions at 0.5h post-exposure for EGFR and COX-2 and at 4h post-exposure for EGF and ICAM-1. It was suggested that SO(2) derivatives could increase the expressions of EGF, EGFR, ICAM-1 and COX-2 on the transcription and translation levels in BEP2D cells, and result in mucus over-production and inflammation responses. This might be one of the possible mechanisms that SO(2) aggravates asthma disease.

Topics: Air Pollutants; Asthma; Bronchi; Cell Line; Cyclooxygenase 2; Epidermal Growth Factor; Epithelial Cells; ErbB Receptors; Gene Expression; Humans; Intercellular Adhesion Molecule-1; RNA, Messenger; Sulfur Dioxide

Airway remodeling in asthma is the result of increased expression of connective tissue proteins, airway smooth muscle cell (ASMC) hyperplasia and hypertrophy. TGF-beta1 has been found to increase ASMC proliferation. The activation of mitogen-activated protein kinases (MAPKs), p38, ERK, and JNK, is critical to the signal transduction associated with cell proliferation. In the present study, we determined the role of phosphorylated MAPKs in TGF-beta1 induced ASMC proliferation.. Confluent and growth-arrested bovine ASMCs were treated with TGF-beta1. Proliferation was measured by [3H]-thymidine incorporation and cell counting. Expressions of phosphorylated p38, ERK1/2, and JNK were determined by Western analysis.. In a concentration-dependent manner, TGF-beta1 increased [3H]-thymidine incorporation and cell number of ASMCs. TGF-beta1 also enhanced serum-induced ASMC proliferation. Although ASMCs cultured with TGF-beta1 had a significant increase in phosphorylated p38, ERK1/2, and JNK, the maximal phosphorylation of each MAPK had a varied onset after incubation with TGF-beta1. TGF-beta1 induced DNA synthesis was inhibited by SB 203580 or PD 98059, selective inhibitors of p38 and MAP kinase kinase (MEK), respectively. Antibodies against EGF, FGF-2, IGF-I, and PDGF did not inhibit the TGF-beta1 induced DNA synthesis.. Our data indicate that ASMCs proliferate in response to TGF-beta1, which is mediated by phosphorylation of p38 and ERK1/2. These findings suggest that TGF-beta1 which is expressed in airways of asthmatics may contribute to irreversible airway remodeling by enhancing ASMC proliferation.

Topics: Animals; Antibodies; Asthma; Blood Proteins; Cattle; Cell Division; Cells, Cultured; Drug Synergism; Epidermal Growth Factor; Extracellular Signal-Regulated MAP Kinases; Fibroblast Growth Factor 2; Insulin-Like Growth Factor I; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Myocytes, Smooth Muscle; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Platelet-Derived Growth Factor; Trachea; Transforming Growth Factor beta; Transforming Growth Factor beta1

Convincing evidence of epithelial damage and aberrant repair exists in adult asthmatic airways, even in the absence of inflammation. However, comparable studies in children have been limited by access and availability of clinical samples.. To determine whether bronchial epithelial cells from children with asthma are inherently distinct from those obtained from children without asthma.. Epithelial cells were obtained by nonbronchoscopic bronchial brushing of children with mild asthma (n = 7), atopic children without asthma (n = 9), and healthy children (n = 12). Cells were subject to morphologic, biochemical, molecular, and functional assessment. Responses were also compared with commercially available epithelial cultures and the transformed cell line 16HBE140.. All epithelial cells exhibited a "cobblestone" morphology, which was maintained throughout culture and repeated passage. Expression of cytokeratin 19 varied, with disease phenotype being greatest in healthy nonatopics and lowest in asthmatics. In contrast, expression of cytokeratin 5/14 was greatest in asthmatic samples and least in healthy nonatopic samples. Asthmatic epithelial cells also spontaneously produced significantly greater amounts of interleukin (IL)-6, prostaglandin E2, and epidermal growth factor, and equivalent amounts of IL-1beta and soluble intracellular adhesion molecule-1, but significantly lower amounts of transforming growth factor beta1. This profile was maintained through successive passages. Asthmatic epithelial cells also exhibited greater rates of proliferation than nonasthmatic cells.. This study has shown that epithelial cells from children with mild asthma are intrinsically different both biochemically and functionally compared with epithelial cells from children without asthma. Importantly, these differences are maintained over successive passages, suggesting that they are not dependent on an in vivo environment.

Topics: Adolescent; Asthma; Blotting, Western; Bronchi; Child; Child, Preschool; Cytokines; Epidermal Growth Factor; Epithelial Cells; Female; Humans; Immunohistochemistry; Interleukin-6; Phenotype

Topics: Asthma; Cell Proliferation; Child; Epidermal Growth Factor; Epithelial Cells; Humans; Immunohistochemistry

Airway smooth muscle (ASM) hypertrophy and hyperplasia, important pathological features in chronic severe asthma, likely contribute to irreversible airflow obstruction. Despite considerable research effort, the precise cellular mechanisms that modulate ASM growth remain unknown. Src, a nonreceptor tyrosine kinase proto-oncogene, reportedly modulates cell proliferative responses to growth factors, contractile agonists, and inflammatory mediators. Here, we show that Src activation is required for human ASM mitogenesis and motility. Platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and thrombin induce rapid activation of Src, and inhibition of Src induces a concentration-dependent abrogation of PDGF-, EGF-, and thrombin-induced ASM cell proliferation. Src immunoprecipitates had associated phosphatidylinositol 3-kinase, or PI3K, activation in response to PDGF and thrombin but not EGF. Further, Src activation is both necessary and sufficient for the stimulation of DNA synthesis as demonstrated by dominant negative Src inhibition of PDGF-, EGF-, and thrombin-induced DNA synthesis. Human ASM cell migration was also attenuated by transfection of cells with dominant negative Src. Further, expression of constitutively active Src promoted cell migration. Collectively, these data demonstrate that Src modulates human ASM cell proliferation and migration, suggesting that Src may play an important role in promoting ASM cell growth and migration that occur in airway remodeling found in asthma and chronic obstructive pulmonary disease, or COPD.

Topics: Asthma; Cell Division; Cell Movement; Cells, Cultured; DNA; Enzyme Activation; Enzyme Inhibitors; Epidermal Growth Factor; Gene Expression; Humans; Immunoblotting; Muscle, Smooth; Mutation; Phosphatidylinositol 3-Kinases; Platelet-Derived Growth Factor; Proto-Oncogene Mas; Pulmonary Disease, Chronic Obstructive; Recombinant Fusion Proteins; src-Family Kinases; Thrombin; Trachea; Transfection

Vascular endothelial growth factor (VEGF), AA isoform of platelet-derived growth factor (PDGF-AA), and epidermal growth factor (EGF) are involved in the pathogenesis of airway inflammation in asthma. These molecules are closely associated with cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-4. This study investigates the relation between childhood asthma and levels of these mediators in exhaled breath condensate (EBC).. EBC was collected from asthmatic children and controls using a disposable collection kit, and the concentrations of VEGF, PDGF-AA, EGF, TNF-alpha and IL-4 in EBC were measured using sandwich enzyme immunoassays. Exhaled nitric oxide concentration was measured by a chemiluminescence analyzer.. Thirty-five asthmatic patients aged between 7 and 18 years and 11 controls were recruited. Sixteen patients had intermittent asthma (IA) whereas 19 of them suffered from persistent asthma (PA). A significant correlation was found between IL-4 and TNF-alpha in EBC (rho = 0.374, p = 0.010). PDGF-AA levels in EBC were higher in subjects with diminished FEV1 (p = 0.023) whereas IL-4 concentrations were increased in asthmatics (p = 0.007) as well as subjects with increased plasma total IgE (p = 0.033). Patients with PA receiving high-dose inhaled corticosteroid (ICS) had higher EBC IL-4 concentration than those on low-dose ICS (p = 0.007). Linear regression revealed that PDGF-AA levels in EBC were negatively associated with FEV1 percentage (beta = -0.459, p = 0.006) among the asthmatic patients.. IL-4 in EBC is increased in childhood asthma, and growth factors are detectable in a significant proportion of these children. Increased PDGF-AA is found in asthmatics with more severe airflow limitation.

Topics: Adolescent; Asthma; Breath Tests; Child; Cytokines; Epidermal Growth Factor; Female; Forced Expiratory Volume; Growth Substances; Humans; Immunoglobulin E; Interleukin-4; Male; Nitric Oxide; Platelet-Derived Growth Factor; Statistics, Nonparametric; Tumor Necrosis Factor-alpha; Vascular Endothelial Growth Factor A; Vital Capacity

Growth factors produced by airway epithelial cells may be important in the pathogenesis of subepithelial fibrosis, a distinctive lesion of chronic human asthma.. To examine the relationship between the development of subepithelial fibrosis and the expression of transforming growth factor-beta 1 (TGF-beta 1) and ligands for the epidermal growth factor receptor.. BALB/c mice sensitized to ovalbumin were chronically challenged by inhalation of low levels of antigen, leading to development of subepithelial fibrosis and other changes of airway wall remodelling. Growth factor expression was assessed by immunohistochemistry and enzyme immunoassay.. Allergic sensitization directly correlated with airway epithelial expression of both the cleaved, potentially biologically active form of TGF-beta 1 and of amphiregulin in response to allergen challenge. Accumulation of TGF-beta 1 was related to remodelling of the airway wall in chronic asthma, whereas expression of amphiregulin did not exhibit a similar relationship. Production of epithelial cell-derived TGF-beta 1 appeared to be regulated by IL-13, while both IL-13 and CD4(+) T cells regulated accumulation of TGF-beta 1. In contrast to results reported in high-level exposure models of airway fibrosis, eosinophils did not appear to be a significant source of TGF-beta 1.. Airway epithelial cell-derived TGF-beta 1 has a potentially crucial role in the development of airway wall remodelling in asthma. Immunological mechanisms may regulate the release and accumulation of TGF-beta 1.

Topics: Allergens; Amphiregulin; Animals; Asthma; Bronchoalveolar Lavage Fluid; CD4-Positive T-Lymphocytes; Chronic Disease; Disease Models, Animal; EGF Family of Proteins; Epidermal Growth Factor; Epithelial Cells; Female; Fibrosis; Glycoproteins; Immunoenzyme Techniques; Intercellular Signaling Peptides and Proteins; Interleukin-13; Ligands; Mice; Mice, Inbred BALB C; Ovalbumin; Respiratory Mucosa; Trachea; Transforming Growth Factor beta; Transforming Growth Factor beta1

Because the asthmatic bronchial epithelium is characterized by widespread damage, we postulated that this is associated with expression of cell cycle inhibitors that control proliferation. Using bronchial biopsies, the epithelium was the major site of expression of the cyclin-dependent kinase inhibitor, p21(waf). Immunostaining usually occurred in the cytoplasm of columnar cells; however, in severe asthma, nuclear staining was also evident in the proliferative, basal cell compartment. p21(waf) expression was significantly higher in asthmatic versus nonasthmatic epithelium and was unaffected by corticosteroid treatment; proliferating cell nuclear antigen was not significantly different in any group. p21(waf), but not p27(kip1), mRNA and protein were induced by treatment of bronchial epithelial cells in vitro with transforming growth factor (TGF)-beta or H2O2, but not by dexamethasone, which induced p57(kip2). TGF-beta and dexamethasone inhibited epidermal growth factor (EGF)-induced DNA synthesis, whereas low concentrations of H2O2 synergized with EGF; at higher doses, growth inhibition and induction of apoptosis occurred. TGF-beta caused p21(waf) to become nuclear, suggesting interaction with the replicative machinery; however, in oxidant-stressed cells, p21(waf) was predominantly cytoplasmic, where it has been linked to cell survival. We conclude that p21(waf) overexpression in asthma influences cell proliferation and survival. This may cause abnormal repair responses that contribute to airway inflammation and remodeling.

Topics: Asthma; Blotting, Western; Bronchi; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Dexamethasone; DNA Replication; Epidermal Growth Factor; Epithelial Cells; Flow Cytometry; Humans; Hydrogen Peroxide; Immunohistochemistry; Proliferating Cell Nuclear Antigen; RNA, Messenger; Transforming Growth Factor beta

The c-erbB family of receptor tyrosine kinases act in a combinatorial fashion to regulate cell behavior. Disturbances in this system have been associated with neoplastic and inflammatory diseases.. Although expression of the epidermal growth factor receptor (EGFR; c-erbB1) is increased in the bronchial epithelium in asthma, there is no information on expression of other members of the c-erbB receptor and ligand family that can modulate EGFR function.. Immunohistochemistry was used to compare expression of EGFR, c-erbB2, c-erbB3, epidermal growth factor, heparin-binding epidermal growth factor-like growth factor, and transforming growth factor alpha in bronchial biopsy specimens from normal and asthmatic subjects. Scrape-wounded monolayers of 16HBE 14o(-) cells were used as an in vitro model of damage and repair. Changes in EGFR, c-erbB2, and c-erbB3 distribution were measured by means of immunocytochemistry, whereas tyrosine phosphorylation was measured by means of immunoprecipitation and Western blotting.. Although epithelial staining for the EGFR was significantly increased in asthmatic epithelium (P <.001), there was no difference in staining for the other receptors and ligands studied. In scrape-wounded epithelial monolayers, tyrosine phosphorylation of EGFR, c-erbB2, and c-erbB3 occurred immediately after damage; however, only EGFR showed a change in expression in response to damage.. Even though EGFR levels are increased in asthma, this is not linked to changes in expression of its activating ligands or other c-erbB receptors. Because bronchial epithelial cells respond to physical damage through activation of several c-erbB family members, the shift in favor of increased EGFR levels in asthma may lead to altered epithelial function by influencing the number and type of heterodimeric signaling complexes, assuming sufficient ligand availability.

Topics: Adult; Asthma; Bronchi; Epidermal Growth Factor; Epithelium; ErbB Receptors; Female; Heparin-binding EGF-like Growth Factor; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Male; Receptor, ErbB-2; Receptor, ErbB-3; Transforming Growth Factor alpha

Adhesion molecules are involved in inflammatory and repair processes of the bronchial epithelium. ICAM-1 is mainly involved in inflammatory reactions, whereas integrins, such as alpha3beta1, are mainly involved in repair processes.. Using bronchial biopsies from 10 asthmatics and eight controls, we first evaluated by immunohistochemistry expression of alpha3beta1 and ICAM-1 in intact and damaged epithelium. Then, using the human pulmonary epithelial cell line WI-26 VA, we studied, by flow-cytometry, the modulation of ICAM-1 and alpha3beta1 expression, and, by ELISA, the release of fibronectin by proinflammatory cytokines, such as IL-5, and anti-inflammatory cytokines, such as IL-4, TGF-beta, and EGF.. alpha3beta1 expression was slightly higher in asthma than in controls, as well as in damaged epithelium than in undamaged epithelium. ICAM-1 expression was higher in asthma than in controls, and similarly distributed in intact or damaged epithelium. In vitro, alpha3beta1 was significantly increased by TGF-beta, EGF, and IL-4, and significantly decreased by IL-5. Fibronectin release was significantly increased by TGF-beta and IL-4, unchanged by EGF, and slightly but significantly decreased by IL-5. ICAM-1 expression was significantly decreased by TGF-beta and IL-4, unchanged by EGF, and significantly increased by IL-5.. These differences in adhesion molecule expression and fibronectin release may be important in epithelial cell inflammation and repair.

Topics: Adolescent; Adult; Aged; Asthma; Biopsy; Bronchi; Cell Line; Cytokines; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Epithelial Cells; Fibronectins; Flow Cytometry; Humans; Inflammation; Integrin alpha3beta1; Integrins; Intercellular Adhesion Molecule-1; Interleukin-4; Middle Aged; Respiratory Mucosa; Transforming Growth Factor beta

Chronic airway inflammation, one of the pathophysiologic features of bronchial asthma, is suspected to be responsible for irreversible pathological changes of airways, called airway remodeling. To examine the mechanisms of airway remodeling in asthma, we investigated the expression of epidermal growth factor (EGF) and its receptor immunohistochemically in asthmatic human airways. Airway specimens from seven patients with asthma were obtained from autopsied and surgically resected lungs. Control specimens were obtained from lungs of eight subjects without asthma and other pulmonary complications at autopsy. We stained those specimens by the avidin-biotin-peroxidase complex (ABC) method with anti-human polyclonal EGF antibody and monoclonal EGF receptor antibodies. Three different portions of airways-large bronchi (about 1 cm in diameter), small bronchi (about 3 mm in diameter), and peripheral airways (less than 2 mm in diameter)-were examined. The thickness of the bronchial smooth muscle and basement membrane was significantly greater in the asthmatic airways than in controls. Clear immunoreactivities of EGF were widely observed on bronchial epithelium, glands, and smooth muscle in asthmatic airways. In the controls, the bronchial epithelium and the bronchial glands partially expressed faint EGF immunoreactivity. For the EGF receptor, clear immunoreactivities were also observed on bronchial epithelium, glands, smooth muscle, and basement membrane in asthmatic airways. In control airways, only part of the bronchial epithelium and smooth muscle weakly expressed EGF receptor immunoreactivity. These results suggest a possible contribution of EGF to the pathophysiology of bronchial asthma, including airway remodeling.

Topics: Adult; Aged; Aged, 80 and over; Asthma; Basement Membrane; Bronchi; Epidermal Growth Factor; Epithelium; ErbB Receptors; Female; Humans; Immunohistochemistry; Male; Middle Aged; Muscle, Smooth

The cysteinyl leukotrienes (CysLTs) mimic many of the features of asthma and are implicated in its pathophysiology. Little, however, is known about the effects of the CysLTs on airways remodeling. In this study the effects of leukotriene D4 (LTD4) on human airway smooth muscle (HASM) cell proliferation and expression of extracellular matrix proteins were investigated. LTD4 (0.1-10 microM) alone had no effect on DNA synthesis in HASM. LTD4, however, markedly augmented proliferation induced by the mitogen, epidermal growth factor (EGF, 1 ng/ml). The potentiating effect of LTD4 (1 microM) on EGF-induced DNA synthesis was abolished by pranlukast (1 microM) or pobilukast (30 microM), but unaffected by zafirlukast (1 microM). In contrast, pranlukast (pKB = 6.9), pobilukast (pKB = 7.0), and zafirlukast (pKB = 6.5) had equivalent potencies for inhibition of LTD4-induced contraction in human bronchus. LTD4 (0.1 or 10 microM) did not increase the total messenger RNA expression of the extracellular matrix proteins (pro-alpha[I] type I or alpha1[IV] type IV collagen), elastin, biglycan, decorin, and fibronectin, and did not influence tumor growth factor-beta (10 ng/ml)-induced effects on the expression of these proteins in HASM cells. These data indicate that LTD4 augments growth factor-induced HASM proliferation but does not alter the expression of various extracellular matrix components. The observed differences in sensitivity to the antagonists suggests that the former phenomenon may be mediated by a CysLT receptor distinct from that which mediates LTD4-induced HASM contraction. Collectively, these results provide preliminary evidence that CysLTs may play a role in airways remodeling in asthma.

Topics: Asthma; Carbachol; Cells, Cultured; Chromones; Dicarboxylic Acids; DNA Replication; Epidermal Growth Factor; Extracellular Matrix Proteins; Gene Expression Regulation; Humans; Indoles; Leukotriene Antagonists; Leukotriene D4; Membrane Proteins; Muscle Contraction; Muscle, Smooth, Vascular; Phenylcarbamates; Receptors, Leukotriene; RNA, Messenger; Sulfonamides; Tosyl Compounds; Trachea; Transforming Growth Factor beta

1. Airway remodelling occurs in asthma and involves an increase in airway smooth muscle mass through cell proliferation and hypertrophy. Increased eosinophil density in the airways is a feature of asthma. Eosinophils exhibiting activation in the airways of asthmatics also exhibit increased expression of transforming growth factor beta (TGF-beta1). We have examined the capacity of TGF-beta1 and epidermal growth factor (EGF) to influence airway smooth muscle division and the effect of heparin on TGF-beta1. EGF and serum-induced smooth muscle DNA synthesis in confluent airway smooth muscle cells (ASMC) as an indication of entry into S phase preceding mitogenesis. 2. ASMC were obtained from cell populations growing out from explanted bovine trachealis muscle sections. Cell division was monitored in sparse plated cells by direct cell counting following nuclear staining. Cell DNA synthesis in confluent cells was monitored by uptake of [3H]-thymidine. 3. TGF-beta1 (100 microM) inhibited FBS (10%)-induced smooth muscle division in sparsely plated cells (40%). TGF-beta1 (100 pM) increased cell DNA synthesis (200%) in confluent cells in the presence of bovine serum albumin (BSA, 0.25%). EGF (0.7 nM) also increased airway smooth muscle DNA synthesis (69%) in the presence of BSA (0.25%). The facilitatory effect of TGF-beta1 was observed between 1-100 pM, while that of EGF was observed between 20 200 pM. 4. Heparin inhibited serum and TGF-beta1-induced DNA synthesis in confluent ASMC (55%), consistent with our previous observation of inhibition of division in sparsely populated ASMC (Kilfeather et al., 1995a). This action of heparin was observed between concentrations of 1-100 microg ml(-1). Heparin did not inhibit DNA synthesis in response to EGF. An anti-mitogenic effect of heparin was also observed against responses to combined exposure to TGF-beta1 and EGF. 5. There was a clear inhibitory effect of heparin in absolute terms against serum-induced division in cells plated at 10, 20 and 45 x 10(3) cells cm(-2). The inhibitory effect of heparin was also observed at a plating density of 45,000 cells cm(-2) when responses to serum were expressed as fold-stimulation of basal DNA synthesis. 6. These findings demonstrate a potential role of TGF-beta1, EGF and heparin-related molecules in regulation of airway smooth muscle division.

Topics: Animals; Asthma; Blood Physiological Phenomena; Cattle; Cell Division; Cells, Cultured; Dose-Response Relationship, Drug; Epidermal Growth Factor; Heparin; Muscle, Smooth; Nucleic Acid Synthesis Inhibitors; Trachea; Transforming Growth Factor beta

We assessed whether transforming growth factor-beta (TGF-beta), a fibrogenic growth factor, may be involved in remodeling of asthma and chronic bronchitis; its expression was compared with that of epidermal growth factor (EGF) and granulocyte macrophage colony-stimulating factor (GM-CSF) in bronchial mucosal biopsies from 13 normal subjects, 24 asthmatics, and 19 patients with chronic bronchitis. TGF-beta immunoreactivity was highly increased in epithelium and submucosa of those with bronchitis and to a lesser extent in asthmatics. By comparison, with normal subjects, EGF immunoreactivity was significantly increased in the epithelium of bronchitic subjects and submucosa of asthmatics, and, GM-CSF immunoreactivity was increased in both epithelial and submucosal cells of asthmatics and to a lesser extent in submucosa of bronchitics. A significant correlation was found between the number of epithelial or submucosal cells expressing TGF-beta in both asthma and chronic bronchitis and basement membrane thickness and fibroblast number. No such correlation was found for EGF or GM-CSF. in situ hybridization for TGF-beta 1 mRNA confirmed the results obtained by immunohistochemistry. By combining in situ hybridization and immunohistochemistry, it was found that eosinophils and fibroblasts were synthetizing TGF-beta in asthma and bronchitis. These data suggest that TGF-beta, but not EGF or GM-CSF, is involved in airways remodeling in asthma and chronic bronchitis.

Topics: Adolescent; Adult; Aged; Asthma; Biopsy; Bronchi; Bronchitis; Chronic Disease; Epidermal Growth Factor; Epithelium; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Immunohistochemistry; In Situ Hybridization; Middle Aged; Mucous Membrane; Transforming Growth Factor beta

We studied the effects of amoxanox (AA-673) on allergic asthma and spasmogen-induced bronchoconstriction in guinea pigs and rats. Amoxanox given orally or parenterally inhibited allergic asthma mediated by IgE, IgG1, or heterologous IgG in guinea pigs and by IgE in rats. This compound also reduced leukotriene D4- and platelet-activating factor-induced bronchoconstriction in guinea pigs, strongly suggesting an antagonistic activity against slow reacting substance of anaphylaxis (SRS-A). Histamine- or acetylcholine-induced bronchoconstriction was not significantly affected by amoxanox. These antiasthmatic effects of amoxanox seem to be associated with an inhibition of the release of chemical mediators such as histamine and SRS-A and with an antagonism against SRS-A.

Topics: Aminopyridines; Animals; Asthma; Bronchi; Cromolyn Sodium; Epidermal Growth Factor; Female; Guinea Pigs; Histamine Release; Immunoglobulin E; In Vitro Techniques; Male; Rats; Rats, Inbred Strains; SRS-A