Cytokine release and adhesion molecule expression by stimulated human bronchial epithelial cells are downregulated by salmeterol

Maoto, a traditional Japanese medicine, controls acute systemic inflammation induced by polyI:C administration through noradrenergic function

Maoto, a traditional Japanese medicine (Kampo), is widely used to treat upper respiratory tract infections, including influenza virus infection. Although maoto is known to inhibit pro-inflammatory responses in a rodent model of acute inflammation, its underlying mechanism remains to be determined. In this study, we investigated the involvement of immune responses and noradrenergic function in the inhibitory action of maoto. In a mouse model of polyI:C-induced acute inflammation, maoto was administered orally in conjunction with intraperitoneal injection of PolyI:C (6 mg/kg), and blood was collected after 2 h for measurement of plasma cytokines by ELISA. Maoto significantly decreased PolyI:C-induced TNF-α levels and increased IL-10 production. Neither pretreatment with IL-10 neutralizing antibodies nor T-cell deficiency using nude mice modified the inhibitory effect of maoto, indicating that the anti-inflammatory effects of maoto are independent of IL-10 and T cells. Furthermore, the inhibitory effects of maoto on PolyI:C-induced TNF-α production were not observed in ex vivo splenocytes, suggesting that maoto does not act directly on inflammatory cells. Lastly, pretreatment with a β-adrenergic receptor antagonist partially cancelled the anti-inflammatory effects of maoto. Collectively, these results suggest that maoto mediates its anti-inflammatory effects via β-adrenergic receptors in vivo.

Inhaled β2 Adrenergic Agonists and Other cAMP-Elevating Agents: Therapeutics for Alveolar Injury and Acute Respiratory Disease Syndrome?

Inhaled long-acting β-adrenergic agonists (LABAs) and short-acting β-adrenergic agonists are approved for the treatment of obstructive lung disease via actions mediated by β2 adrenergic receptors (β2-ARs) that increase cellular cAMP synthesis. This review discusses the potential of β2-AR agonists, in particular LABAs, for the treatment of acute respiratory distress syndrome (ARDS). We emphasize ARDS induced by pneumonia and focus on the pathobiology of ARDS and actions of LABAs and cAMP on pulmonary and immune cell types. β2-AR agonists/cAMP have beneficial actions that include protection of epithelial and endothelial cells from injury, restoration of alveolar fluid clearance, and reduction of fibrotic remodeling. β2-AR agonists/cAMP also exert anti-inflammatory effects on the immune system by actions on several types of immune cells. Early administration is likely critical for optimizing efficacy of LABAs or other cAMP-elevating agents, such as agonists of other Gs-coupled G protein-coupled receptors or cyclic nucleotide phosphodiesterase inhibitors. Clinical studies that target lung injury early, prior to development of ARDS, are thus needed to further assess the use of inhaled LABAs, perhaps combined with inhaled corticosteroids and/or long-acting muscarinic cholinergic antagonists. Such agents may provide a multipronged, repurposing, and efficacious therapeutic approach while minimizing systemic toxicity. SIGNIFICANCE STATEMENT: Acute respiratory distress syndrome (ARDS) after pulmonary alveolar injury (e.g., certain viral infections) is associated with ∼40% mortality and in need of new therapeutic approaches. This review summarizes the pathobiology of ARDS, focusing on contributions of pulmonary and immune cell types and potentially beneficial actions of β2 adrenergic receptors and cAMP. Early administration of inhaled β2 adrenergic agonists and perhaps other cAMP-elevating agents after alveolar injury may be a prophylactic approach to prevent development of ARDS.

LasR-deficient Pseudomonas aeruginosa variants increase airway epithelial mICAM-1 expression and enhance neutrophilic lung inflammation

Pseudomonas aeruginosa causes chronic airway infections, a major determinant of lung inflammation and damage in cystic fibrosis (CF). Loss-of-function lasR mutants commonly arise during chronic CF infections, are associated with accelerated lung function decline in CF patients and induce exaggerated neutrophilic inflammation in model systems. In this study, we investigated how lasR mutants modulate airway epithelial membrane bound ICAM-1 (mICAM-1), a surface adhesion molecule, and determined its impact on neutrophilic inflammation in vitro and in vivo. We demonstrated that LasR-deficient strains induce increased mICAM-1 levels in airway epithelial cells compared to wild-type strains, an effect attributable to the loss of mICAM-1 degradation by LasR-regulated proteases and associated with enhanced neutrophil adhesion. In a subacute airway infection model, we also observed that lasR mutant-infected mice displayed greater airway epithelial ICAM-1 expression and increased neutrophilic pulmonary inflammation. Our findings provide new insights into the intricate interplay between lasR mutants, LasR-regulated proteases and airway epithelial ICAM-1 expression, and reveal a new mechanism involved in the exaggerated inflammatory response induced by lasR mutants.

Adrenergic Signaling at the Interface of Allergic Asthma and Viral Infections

Upper respiratory viral infections are a major etiologic instigator of allergic asthma, and they drive severe exacerbations of allergic inflammation in the lower airways of asthma sufferers. Rhinovirus (RV), in particular, is the main viral instigator of these pathologies. Asthma exacerbations due to RV infections are the most frequent reasons for hospitalization and account for the majority of morbidity and mortality in asthma patients. In both critical care and disease control, long- and short-acting β2-agonists are the first line of therapeutic intervention, which are used to restore airway function by promoting smooth muscle cell relaxation in bronchioles. While prophylactic use of β2-agonists reduces the frequency and pathology of exacerbations, their role in modulating the inflammatory response is only now being appreciated. Adrenergic signaling is a component of the sympathetic nervous system, and the natural ligands, epinephrine and norepinephrine (NE), regulate a multitude of autonomic functions including regulation of both the innate and adaptive immune response. NE is the primary neurotransmitter released by post-ganglionic sympathetic neurons that innervate most all peripheral tissues including lung and secondary lymphoid organs. Thus, the adrenergic signaling pathways are in direct contact with both the central and peripheral immune compartments. We present a perspective on how the adrenergic signaling pathway controls immune function and how β2-agonists may influence inflammation in the context of virus-induced asthma exacerbations.

Chronic inflammatory airway diseases: the central role of the epithelium revisited

The respiratory epithelium plays a critical role for the maintenance of airway integrity and defense against inhaled particles. Physical barrier provided by apical junctions and mucociliary clearance clears inhaled pathogens, allergens or toxics, to prevent continuous stimulation of adaptive immune responses. The "chemical barrier", consisting of several anti-microbial factors such as lysozyme and lactoferrin, constitutes another protective mechanism of the mucosae against external aggressions before adaptive immune response starts. The reconstruction of damaged respiratory epithelium is crucial to restore this barrier. This review examines the role of the airway epithelium through recent advances in health and chronic inflammatory diseases in the lower conducting airways (in asthma and chronic obstructive pulmonary disease). Better understanding of normal and altered epithelial functions continuously provides new insights into the physiopathology of chronic airway diseases and should help to identify new epithelial-targeted therapies.

Asthma is not only an airway disease, but also a vascular disease

Multiple studies have identified an expansion and morphological dysregulation of the bronchial vascular network in the airways of asthmatics. Increased number, size and density of blood vessels, as well as vascular leakage and plasma engorgement, have been reported in the airways of patients with all grades of asthma from mild to fatal. This neovascularisation is an increasingly commonly reported feature of airway remodelling; however, the pathophysiological impact of the increased vasculature in the bronchial wall and its significance to pulmonary function in asthma are unrecognised at this time. Multiple factors capable of influencing the development and persistence of the vascular network exist within asthmatic airway tissue. These include structural components of the altered extracellular matrix (ECM), imbalance of proteases and their endogenous inhibitors, release of active matrikines and the dysregulated levels of both soluble and matrix sequestered growth factors. This review will explore the features of the asthmatic airway which influence the development and persistence of the increased vascular network, as well as the effect of enhanced tissue perfusion on chronic inflammation and airway dynamics. The response of cells of the airways to the altered vascular profile and the subsequent influence on the features of airway remodelling will also be highlighted. We will explore the failure of current asthma therapeutics in "normalising" this vascular remodelling. Finally, we will summarize the outcomes of recent clinical trials which provide hope that anti-angiogenic therapies may be a potent asthma-resolving class of drugs and provide a new approach to asthma management in the future.

Anti-inflammatory effects of β2 adrenergic receptor agonists in experimental acute lung injury

These studies were undertaken to extend emerging evidence that β(2) adrenergic receptor (β(2)AR) agonists, in addition to their bronchorelaxing effects, may have broad anti-inflammatory effects in the lung following onset of experimental acute lung injury (ALI). Young male C57BL/6 mice (25 g) developed ALI following airway deposition of bacterial LPS or IgG immune complexes in the absence or presence of appropriate stereoisomers (enantiomers) of β(2)AR agonists, albuterol or formoterol. Endpoints included albumin leak into lung and buildup of polymorphonuclear neutrophils and cytokines/chemokines in bronchoalveolar fluids. Both β(2)AR agonists suppressed lung inflammatory parameters (IC(50)=10(-7) M). Similar effects of β(2)AR agonists on mediator release were found when mouse macrophages were stimulated in vitro with LPS. The protective effects were associated with reduced activation (phosphorylation) of JNK but not of other signaling proteins. Collectively, these data suggest that β(2)AR agonists have broad anti-inflammatory effects in the setting of ALI. While β(2)AR agonists suppress JNK activation, the extent to which this can explain the blunted lung inflammatory responses in the ALI models remains to be determined.

Modulation by flunisolide of tumor necrosis factor-alpha-induced stimulation of airway epithelial cell activities related to eosinophil inflammation

BACKGROUND

Tumor necrosis factor (TNF)-alpha, a proinflammatory cytokine involved in the pathogenesis of asthma, displays multiple functions on a variety of cells, including bronchial epithelial cells (BECs).

OBJECTIVE

To characterize in vitro changes induced by TNF-alpha on the function of BECs that may be related to eosinophilic inflammation and to evaluate their modulation by an inhaled corticosteroid, flunisolide.

METHODS

A normal human bronchial epithelial cell line (BEAS-2B) was incubated with TNF-alpha (10 ng/ml) to evaluate (a) intercellular adhesion molecule (ICAM)-1 expression and granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-5 release by BEAS-2B; (b) eosinophil adhesion to BEAS-2B; and (c) the modulation of these activities by flunisolide (0.1 to 10 microM).

RESULTS

Stimulation of BEAS-2 with TNF-alpha generated an increase in ICAM-1 expression (p = .0012), in GM-CSF and IL-5 release (p < .01), and in eosinophil adhesion to BEAS-2B, but this latter effect did not reach statistical significance. Flunisolide at all the tested concentrations effectively inhibited ICAM-1 expression and GM-CSF and IL-5 release (p < .05). The percent inhibition induced by the highest flunisolide concentration (10 muM) for the various BEAS-2B functions was 30%, 60%, and 70%, respectively. The effect of flunisolide appeared to be related to an inhibition of "TNF-alpha-induced" ICAM-1 expression and cytokine release with little or no involvement of the "constitutive" expression and release.

CONCLUSION

An increase in ICAM-1 expression in BECs was found to be induced by TNF-alpha and associated with enhancement of the constitutive secretion of GM-CSF and IL-5, cytokines related to eosinophilic inflammation. The ability of flunisolide to modulate these BECs activities appears to be mostly related to the inhibition of the "TNF-alpha-induced" responses.

Angiogenesis in asthma

Asthma is a chronic inflammatory disease of the airways characterized by infiltration and activation of inflammatory cells and by structural changes, including subepithelial fibrosis, smooth muscle cells hypertrophy/hyperplasia, epithelial cell metaplasia and angiogenesis. These structural changes are thought to correlate with asthma severity and to account for the development of progressive lung function deterioration. The mechanism underlying airway angiogenesis in asthma and its precise clinical relevance have not yet been completely elucidated. This review provides recent data showing the contribution of allergic inflammation in increased airway vascularity and potential therapeutical approaches in asthma treatment by acting on bronchial microvascular changes.

IFN-gamma regulation of ICAM-1 receptors in bronchial epithelial cells: soluble ICAM-1 release inhibits human rhinovirus infection

Background

Intercellular adhesion molecule-1 (ICAM-1) is a critical target-docking molecule on epithelial cells for 90% of human rhinovirus (HRV) serotypes. Two forms of ICAM-1 exist, membranous (mICAM-1) and soluble (sICAM-1), both expressed by bronchial epithelial cells. Interferon-gamma (IFN-γ), a crucial Th-1 immuno-regulatory mediator, can modulate mICAM-1 expression; however its simultaneous effects on mICAM-1: sICAM-1 levels and their consequent outcome on cell infectivity have not been previously explored.

Methods

Primary normal human bronchial epithelial cells were pre-stimulated with IFN-γ (1 ng/ml for 24 h) and subsequently inoculated with HRV-14 or HRV-1b (TCID₅₀ 10 ^2.5). Epithelial surface ICAM-1 expression and soluble ICAM-1 release were measured at the protein and gene level by immunofluorescence and ELISA respectively; mRNA levels were semi-quantified using RT-PCR. Molecular mechanisms regulating ICAM-1 isoform expression and effects on epithelial cell infectivity were explored.

Results

In IFN-γ-biased cells infected with HRV-14, but not HRV-1b, mICAM-1 expression is down-regulated, with simultaneous induction of sICAM-1 release. This differential effect on HRV-14 receptor isoforms appears to be related to a combination of decreased IFN-γ-induced JAK-STAT signalling and proteolytic receptor cleavage of the membranous form in IFN-γ-biased HRV-14 infected cells. The observed changes in relative mICAM-1: sICAM-1 expression levels are associated with reduced HRV-14 viral titres.

Conclusion

These findings support the hypothesis that in epithelial cells conditioned to IFN-γ and subsequently exposed to HRV-14 infection, differential modulation in the ratio of ICAM-1 receptors prevails in favour of an anti-viral milieu, appearing to limit further target cell viral attachment and propagation.

Enhanced Ca2+ sensitivity in hyperresponsive cultured bronchi is mediated by TNFalpha and NF-kappaB

The mechanical properties and Ca2+ sensitivity of an organ-culture model derived from guinea pig airways have been examined. The cultured explants develop airway hyperresponsiveness to pharmacological agonists after 3-day culture, when compared with fresh and ovalbumin-sensitized tissues. The reactivity of cultured explants is dependent on the presence of the epithelium. They are also sensitive to glucocorticosteroid pretreatments, which neutralize the TNFalpha antibody and NF-kappaB inhibitor. Hence, specific immunostaining of NF-kappaB subunits (p65 and p50) was increased in the nuclear extract of cultured explants. In beta-escin-permeabilized preparations, step-increases in pCa revealed enhanced Ca2+ sensitivity of the contractile apparatus in cultured explants, which was prevented by epithelium removal. Pretreatments of cultured explants with neutralizing TNFalpha antibody and NF-kappaB inhibitor consistently reduced their Ca2+ sensitivity. These findings suggest that AHR developed in this organ culture model may be triggered by an inflammatory process mediated by the TNFalpha and NF-kappaB transcription factor, which results in an increased sensitivity to [Ca2+]i.

Role of interleukin-8 and growth-regulated oncogene-α in the chemotactic migration of all-trans retinoic acid-treated promyelocytic leukemic cells toward alveolar epithelial cells*

OBJECTIVE

Although all-trans retinoic acid (ATRA) can treat acute promyelocytic leukemia (APL), it also causes retinoic acid syndrome with presentations similar to acute respiratory distress syndrome. We investigated the role of interleukin (IL)-8 and growth-regulated oncogene (GRO)-alpha in the chemotactic transmigration of ATRA-treated NB4 (ATRA-NB4) APL cells toward A549 alveolar epithelial cells.

DESIGN

An in vitro human cell culture study.

SETTING

University hospital research laboratories.

SUBJECTS

NB4 and A549 cells.

INTERVENTIONS

NB4 and A549 cells were separately cultured with ATRA and/or dexamethasone for 1-3 days. NB4 or ATRA-NB4 cells were then placed in an upper insert and co-incubated with A549 cells or their conditioned medium located in a lower plate.

MEASUREMENTS AND MAIN RESULTS

ATRA stimulated NB4 cells to transmigrate toward the A549 cells in a time- and dose-dependent manner. Replacement of A459 condition medium by its original medium abrogated this transmigration. Only A549 cells constitutively secreted GRO-alpha, and both A549 and NB4 cells constitutively secreted IL-8, which was enhanced by ATRA. Exogenous administration of IL-8 or GRO-alpha also promoted the ATRA-NB4 transmigration. The binding assay demonstrated that ATRA-NB4 cells bound IL-8, but not GRO-alpha, more avidly. Pretreatment with antibodies directed against IL-8 and GRO-alpha receptors reduced ATRA-NB4 transmigration by about 60%. Dexamethasone did not suppress their IL-8 secretion and transmigration in ATRA-NB4 cells, but when applied to A549 cells, IL-8 secretion was suppressed but not GRO-alpha secretion, and there was attenuation of ATRA-NB4 transmigration.

CONCLUSIONS

IL-8 and GRO-alpha secreted from alveolar epithelial cells play an important role in the cell-cell interaction involved in the chemotactic transmigration of ATRA-treated APL cells toward alveolar epithelial cells.

Therapeutic approach to vascular remodelling in asthma

Bronchial asthma can be characterized by some significant changes in airway blood vessels, which may contribute to airway remodelling. Despite the clinical and functional consequences of bronchial microvascular remodelling in asthma, up to now, little data have been published on the therapeutic approach to this phenomenon. Corticosteroids are the only anti-asthma drugs that act positively on the three aspects of bronchial vascular remodelling: angiogenesis, dilatation and permeability. Modest positive effects of treatments with beta2-agonists and leukotrienes receptor antagonists on bronchial microcirculatory changes have been reported. In the future, agents that specifically inhibit angiogenesis could represent a novel approach for positively acting on bronchial microvascular changes in chronic inflammatory airway diseases, such as chronic bronchitis and asthma.

New treatment regimes for virus-induced exacerbations of asthma

This review will focus on the role of viruses as causes of asthma exacerbations. The article will briefly review the current literature supporting this view, with a special focus on human rhinovirus (RV), the main virus associated with exacerbations of asthma. The review will then refer to possible strategies for treatment, and will include discussion on treatment with specific anti-viral therapy and type I interferon as a treatment for RV. The review will also include a discussion on current therapies for asthma, such as glucocorticosteroid and beta(2) agonist therapy alone and in combination and why this may be relevant to virus-induced exacerbations of asthma. Finally, the potential for future anti-inflammatory/immunomodulatory therapies with a focus on NF-kappaB inhibition will be discussed.

Induction of IL-6 in co-culture of bronchial epithelial cells and eosinophils is regulated by p38 MAPK and NF-kappaB

BACKGROUND

Prominent infiltration of eosinophils into the airway mucosa and release of inflammatory mediators upon their adhesion onto airway epithelial cells are the immunopathogical mechanisms of allergic asthma.

OBJECTIVE

We investigated the effect of normal and paraformaldyhyde-fixed human eosinophils on BEAS-2B cells, a human bronchial epithelial cell line, for the release of inflammatory cytokine interleukin (IL)-6.

METHODS

Interleukin-6 in cell culture supernatant, protein amount of p38 mitogen-activated protein kinase (MAPK), and nuclear factor-kappaB (NF-kappaB) activity in BEAS-2B cells were analyzed by Western blot and enzyme-linked immunosorbent assay (ELISA). IL-6 gene expression was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR), and p38 MAPK activity and inhibitor (I)kappaB-alpha induction were evaluated by Western blot.

RESULTS

Co-culture of BEAS-2B cells and eosinophils induced a significant elevation of IL-6 expression in BEAS-2B cells. Interaction of eosinophils and BEAS-2B cells led to a marked induction in phospho-p38 MAPK, phospho-IkappaB-alpha and activity of NF-kappaB in BEAS-2B cells. NF-kappaB inhibitor BAY 11-7082 and p38 MAPK inhibitor SB 203580 significantly decreased IL-6 release in a co-culture of BEAS-2B cells and eosinophils. Fixed human eosinophils were able to maintain their ability to induce IL-6 release in co-culture, activate p38 MAPK and NK-kappaB, and up-regulate IL-6 gene expression in BEAS-2B cells.

CONCLUSIONS

These data indicate that the interaction of eosinophils and bronchial epithelial cells plays an important role in airway inflammation, at least partly, via IL-6 induction.

Inhibition of in vitro neutrophil migration through a bilayer of endothelial and epithelial cells using beta2-agonists: concomitant effects on IL-8 and elastase secretion and impact of glucocorticosteroids

BACKGROUND

Beta2-agonists and glucocorticosteroids are two common treatments for COPD and they are often used in combination. Glucocorticosteroids mediate the anti-inflammatory response through the glucocorticosteroid receptors (GRs). Beta2-agonists are potent bronchodilators but they can have some anti-inflammatory properties by elevating the level of intracellular cAMP. In this study we aimed to investigate the anti-inflammatory effect of combination therapy in vitro.

METHODS

Neutrophils or the bilayer of endothelial and epithelial cells were preincubated with salbutamol, budesonide or budesonide followed by salbutamol. FMLP-induced IL-8, elastase release and neutrophil migration through the bilayer was measured.

RESULTS

Salbutamol at concentrations of 10(-4), 10(-5) and 10(-9) M inhibited IL-8, elastase release and migration of neutrophils in an inverse bell-shaped concentration-response manner. When given after budesonide (10(-9) and 10(-8)M), the inhibitory effect on migration was additive. This additive effect was not observed for elastase and IL-8 release.

CONCLUSIONS

Salbutamol inhibits neutrophil migration and IL-8 and elastase release in a concentration-dependent manner. Preincubation with low concentration of budesonide enhanced the inhibition of migration achieved by low concentrations of salbutamol.

Cytokine-activated bronchial epithelial cell pro-inflammatory functions are effectively downregulated in vitro by ciclesonide

Ciclesonide, a new inhaled corticosteroid, is administered as a parent compound and converted in the airway mucosa into the active metabolite, desisobutyryl-(des-)ciclesonide. A study was designed to evaluate the ability of ciclesonide to modulate pro-inflammatory functions of human bronchial epithelial cell (HBEC) primary cultures being converted into des-ciclesonide. HBECs were stimulated with interleukin (IL)-4 and tumour necrosis factor (TNF)-alpha (20 ng/mL) in the presence of ciclesonide and intercellular adhesion molecule (ICAM)-1 expression, granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-8 release evaluated respectively by FACS and ELISA. Ciclesonide (3 microM) significantly inhibited ICAM-1 expression by stimulated HBECs, already after 3h and still after 48 h culture (p < 0.01). At all the concentrations tested ciclesonide inhibited ICAM-1 expression (p < 0.05). GM-CSF and IL-8 release by stimulated HBECs was also downregulated by ciclesonide (p < 0.05). All the ciclesonide activities tested appeared to be mainly due to a partial inhibition of the 'IL-4 + TNF-alpha-induced' and little or no involvement of the 'constitutive' cell functions. Des-ciclesonide was detected in 24 h culture HBEC supernatants using high-performance liquid chromatography, while no parental compound ciclesonide was present. These results show at cellular level the fast and prolonged activity of ciclesonide on pro-inflammatory functions of HBECs, a selective target of asthma therapy, involved in the activation of this new inhaled corticosteroid.