CD40 and OX40 ligand are increased on stimulated asthmatic airway smooth muscle

T cell and airway smooth muscle interaction: a key driver of asthmatic airway inflammation and remodeling

Cross talk between T cells and airway smooth muscle (ASM) may play a role in modulating asthmatic airway inflammation and remodeling. Infiltrating T cells have been observed within the ASM bundles of asthmatics, and a wide range of direct and indirect interactions between T cells and ASM has been demonstrated using various in vitro and in vivo model systems. Contact-dependent mechanisms such as ligation and activation of cellular adhesion and costimulatory molecules, as well as the formation of lymphocyte-derived membrane conduits, facilitate the adhesion, bidirectional communication, and transfer of materials between T and ASM cells. T cell-derived cytokines, particularly of the Th1, Th2, and Th17 subsets, modulate the secretome, proliferation, and contractility of ASM cells. This review summarizes the mechanisms governing T cell-ASM cross talk in the context of asthma. Understanding the underlying mechanistic basis is important for directing future research and developing therapeutic interventions targeted toward this complex interaction.

Engaging stimulatory immune checkpoint interactions in the tumour immune microenvironment of primary liver cancers - how to push the gas after having released the brake

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the first and second most common primary liver cancer (PLC). For decades, systemic therapies consisting of tyrosine kinase inhibitors (TKIs) or chemotherapy have formed the cornerstone of treating advanced-stage HCC and CCA, respectively. More recently, immunotherapy using immune checkpoint inhibition (ICI) has shown anti-tumour reactivity in some patients. The combination regimen of anti-PD-L1 and anti-VEGF antibodies has been approved as new first-line treatment of advanced-stage HCC. Furthermore, gemcibatine plus cisplatin (GEMCIS) with an anti-PD-L1 antibody is awaiting global approval for the treatment of advanced-stage CCA. As effective anti-tumour reactivity using ICI is achieved in a minor subset of both HCC and CCA patients only, alternative immune strategies to sensitise the tumour microenvironment of PLC are waited for. Here we discuss immune checkpoint stimulation (ICS) as additional tool to enhance anti-tumour reactivity. Up-to-date information on the clinical application of ICS in onco-immunology is provided. This review provides a rationale of the application of next-generation ICS either alone or in combination regimen to potentially enhance anti-tumour reactivity in PLC patients.

Bronchial epithelial transcriptomics and experimental validation reveal asthma severity-related neutrophilc signatures and potential treatments

Airway epithelial transcriptome analysis of asthma patients with different severity was used to disentangle the immune infiltration mechanisms affecting asthma exacerbation, which may be advantageous to asthma treatment. Here we introduce various bioinformatics methods and develop two models: an OVA/CFA-induced neutrophil asthma mouse model and an LPS-induced human bronchial epithelial cell damage model. Our objective is to investigate the molecular mechanisms, potential targets, and therapeutic strategies associated with asthma severity. Multiple bioinformatics methods identify meaningful differences in the degree of neutrophil infiltration in asthma patients with different severity. Then, PTPRC, TLR2, MMP9, FCGR3B, TYROBP, CXCR1, S100A12, FPR1, CCR1 and CXCR2 are identified as the hub genes. Furthermore, the mRNA expression of 10 hub genes is determined in vivo and in vitro models. Reperixin is identified as a pivotal drug targeting CXCR1, CXCR2 and MMP9. We further test the potential efficiency of Reperixin in 16HBE cells, and conclude that Reperixin can attenuate LPS-induced cellular damage and inhibit the expression of them. In this study, we successfully identify and validate several neutrophilic signatures and targets associated with asthma severity. Notably, Reperixin displays the ability to target CXCR1, CXCR2, and MMP9, suggesting its potential therapeutic value for managing deteriorating asthma.

Loss of alcohol dehydrogenase 1B in cancer-associated fibroblasts: contribution to the increase of tumor-promoting IL-6 in colon cancer

BACKGROUND

Increases in IL-6 by cancer-associated fibroblasts (CAFs) contribute to colon cancer progression, but the mechanisms involved in the increase of this tumor-promoting cytokine are unknown. The aim of this study was to identify novel targets involved in the dysregulation of IL-6 expression by CAFs in colon cancer.

METHODS

Colonic normal (N), hyperplastic, tubular adenoma, adenocarcinoma tissues, and tissue-derived myo-/fibroblasts (MFs) were used in these studies.

RESULTS

Transcriptomic analysis demonstrated a striking decrease in alcohol dehydrogenase 1B (ADH1B) expression, a gene potentially involved in IL-6 dysregulation in CAFs. ADH1B expression was downregulated in approximately 50% of studied tubular adenomas and all T1-4 colon tumors, but not in hyperplastic polyps. ADH1B metabolizes alcohols, including retinol (RO), and is involved in the generation of all-trans retinoic acid (atRA). LPS-induced IL-6 production was inhibited by either RO or its byproduct atRA in N-MFs, but only atRA was effective in CAFs. Silencing ADH1B in N-MFs significantly upregulated LPS-induced IL-6 similar to those observed in CAFs and lead to the loss of RO inhibitory effect on inducible IL-6 expression.

CONCLUSION

Our data identify ADH1B as a novel potential mesenchymal tumor suppressor, which plays a critical role in ADH1B/retinoid-mediated regulation of tumor-promoting IL-6.

TNFSF4 (OX40L) expression and survival in locally advanced and metastatic melanoma

Immunotherapy with checkpoint inhibitors revolutionized melanoma treatment in both the adjuvant and metastatic setting, yet not all metastatic patients respond, and metastatic disease still often recurs among immunotherapy-treated patients with locally advanced disease. TNFSF4 is a co-stimulatory checkpoint protein expressed by several types of immune and non-immune cells, and was shown in the past to enhance the anti-neoplastic activity of T cells. Here, we assessed its expression in melanoma and its association with outcome in locally advanced and metastatic disease. We used publicly available data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE), and RNA sequencing data from anti-PD1-treated patients at Sheba medical center. TNFSF4 mRNA is expressed in melanoma cell lines and melanoma samples, including those with low lymphocytic infiltrates, and is not associated with the ulceration status of the primary tumor. Low expression of TNFSF4 mRNA is associated with worse prognosis in all melanoma patients and in the cohorts of stage III and stage IIIc-IV patients. Low expression of TNFSF4 mRNAs is also associated with worse prognosis in the subgroup of patients with low lymphocytic infiltrates, suggesting that tumoral TNFSF4 is associated with outcome. TNFSF4 expression was not correlated with the expression of other known checkpoint mRNAs. Last, metastatic patients with TNFSF4 mRNA expression within the lowest quartile have significantly worse outcome on anti-PD1 treatment, and a significantly lower response rate to these agents. Our current work points to TNFSF4 expression in melanoma as a potential determinant of prognosis, and warrants further translational and clinical research.

Correlation of OX40 ligand on B cells with serum total IgE and IL-4 levels by CD4+ T cells in allergic rhinitis

INTRODUCTION AND OBJECTIVES

Allergic rhinitis (AR) is a classic Th2-mediated disease, with important contributions to the pathology of interleukins 4, 5, and 13. The co-stimulatory molecule of OX40 and its ligand interaction participate in the immune response by regulation of Th1/Th2 cells balance. Considering the paucity of information on the relation between OX40 ligand (OX40L) and AR, this study aimed to examine its expression on B lymphocytes.

PATIENTS AND METHODS

This case-control study consisted of 20 AR patients and 20 healthy subjects. The serum level of total immunoglobulin E (IgE) was measured using the electro-chemiluminescence (ECL) technology. The percentage of B-lymphocytes expressing OX40L was assessed by flow cytometry. The amounts of IL-4 in CD4+ T cells culture supernatant was also measured by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

OX40L expression on B lymphocytes of patients was significantly higher than the control group (44.32±19.21% vs. 2.79±2.48% respectively, p<0.001). In AR patients, OX40L expression correlated positively with the levels of serum total IgE and IL-4 produced by CD4+ T lymphocytes (p<0.01 - p<0.05) respectively.

CONCLUSIONS

Collectively, the findings of this work suggest that there is a relationship between the OX40L expression level on B lymphocytes and allergic markers such as IgE and IL-4 in patients with allergic rhinitis.

Cyclooxygenase-2 and microRNA-155 expression are elevated in asthmatic airway smooth muscle cells

Cyclooxygenase-2 (COX-2) expression and PGE2 secretion from human airway smooth muscle cells (hASMCs) may contribute to β2-adrenoceptor hyporesponsiveness, a clinical feature observed in some patients with asthma. hASMCs from patients with asthma exhibit elevated expression of cytokine-responsive genes, and in some instances this is attributable to an altered histone code and/or microRNA expression. We hypothesized that COX-2 expression and PGE2 secretion might be elevated in asthmatic hASMCs in response to proinflammatory signals in part due to altered histone acetylation and/or microRNA expression. hASMCs obtained from nonasthmatic and asthmatic human subjects were treated with cytomix (IL-1β, TNF-α, and IFN-γ). A greater elevation of COX-2 mRNA, COX-2 protein, and PGE2 secretion was observed in the asthmatic cells. We investigated histone H3/H4-acetylation, transcription factor binding, mRNA stability, p38 mitogen-activated protein kinase signaling, and microRNA (miR)-155 expression as potential mechanisms responsible for the differential elevation of COX-2 expression. We found that histone H3/H4-acetylation and transcription factor binding to the COX-2 promoter were similar in both groups, and histone H3/H4-acetylation did not increase after cytomix treatment. Cytomix treatment elevated NF-κB and RNA polymerase II binding to similar levels in both groups. COX-2 mRNA stability was increased in asthmatic cells. MiR-155 expression was higher in cytomix-treated asthmatic cells, and we show it enhances COX-2 expression and PGE2 secretion in asthmatic and nonasthmatic hASMCs. Thus, miR-155 expression positively correlates with COX-2 expression in the asthmatic hASMCs and may contribute to the elevated expression observed in these cells. These findings may explain, at least in part, β2-adrenoceptor hyporesponsiveness in patients with asthma.

Pattern recognition pathways leading to a Th2 cytokine bias in allergic bronchopulmonary aspergillosis patients

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) is characterised by an exaggerated Th2 response to Aspergillus fumigatus, but the immunological pathways responsible for this effect are unknown.

OBJECTIVE

The aim of this study was to decipher the pattern recognition receptors (PRRs) and cytokines involved in the Aspergillus-specific Th2 response and to study Aspergillus-induced responses in healthy controls and ABPA patients.

METHODS

Peripheral blood mononuclear cells (PBMCs) were stimulated with heat-killed Aspergillus conidia, various other pathogens, or PRR ligands. PRRs and cytokine pathways were blocked with PRR-blocking reagents, anti-TNF (Etanercept or Adalimumab), IL-1Ra (Anakinra) or IFNγ (IFN-gamma). ELISA and FACS were used to analyse cytokine responses.

RESULTS

Aspergillus was the only pathogen that stimulated the Th2 cytokines IL-5 and IL-13, while Gram-negative bacteria, Gram-positive bacteria, Candida albicans, chitin, β-glucan or Toll-like receptor (TLR) ligands did not. Depletion of CD4(+) cells abolished IL-13 production. Blocking complement receptor 3 (CR3) significantly reduced IL-5 and IL-13, while blocking TLR2, TLR4 or dectin-1 had no effect. ABPA patients displayed increased Aspergillus-induced IL-5 and IL-13 and decreased IFNγ production compared with healthy controls. All biological agents tested showed the capability to inhibit Th2 responses, but also decreased Aspergillus-induced IFNγ.

CONCLUSIONS AND CLINICAL RELEVANCE

Aspergillus conidia are unique in triggering Th2 responses in human PBMCs, through a CR3-dependent pathway. ABPA patients display a significantly increased Aspergillus-induced Th2/Th1 ratio that can be modulated by biologicals. These data provide a rationale to explore IFNγ therapy in ABPA as a corticosteroid-sparing treatment option, by dampening Th2 responses and supplementing the IFNγ deficiency at the same time.

OX40L blockade and allergen-induced airway responses in subjects with mild asthma

Background

The OX40/OX40L interaction contributes to an optimal T cell response following allergic stimuli and plays an important role in the maintenance and reactivation of memory T effector cells.

Objective

We tested whether treatment with an anti-OX40L monoclonal antibody (MAb) would inhibit allergen-induced responses in subjects with asthma.

Methods

Twenty-eight mild, atopic asthmatic subjects were recruited for a double-blind, randomized, placebo-controlled, parallel-group trial (ClinicalTrials.gov identifier NCT00983658) to compare blockade of OX40L using a humanized anti-OX40L MAb to placebo-administered intravenously in 4 doses over 3 months. Allergen inhalation challenges were carried out 56 and 113 days after the first dose of study drug. The primary outcome variable was the late-phase asthmatic response. Other outcomes included the early-phase asthmatic response, airway hyperresponsiveness, serum IgE levels, blood and sputum eosinophils, safety and tolerability.

Results

Treatment with anti-OX40L MAb did not attenuate the early- or late-phase asthmatic responses at days 56 or 113 compared with placebo. In the anti-OX40L MAb treatment group, total IgE was reduced 17% from pre-dosing levels, and sputum eosinophils decreased 75% by day 113 (both P = 0.04). There was no effect of anti-OX40L MAb on airway hyperresponsiveness or blood eosinophils. The frequency of AEs was similar in both groups.

Conclusion and Clinical Relevance

Pharmacological activity of anti-OX40L MAb was observed by decreases in serum total IgE and airway eosinophils at 16 weeks post-dosing, but there was no effect on allergen-induced airway responses. It is possible that the treatment duration or dose of antibody was insufficient to impact the airway responses.

CD4+ T cells enhance the unloaded shortening velocity of airway smooth muscle by altering the contractile protein expression

Abundant data indicate that pathogenesis in allergic airways disease is orchestrated by an aberrant T-helper 2 (Th2) inflammatory response. CD4(+) T cells have been localized to airway smooth muscle (ASM) in both human asthmatics and in rodent models of allergic airways disease, where they have been implicated in proliferative responses of ASM. Whether CD4(+) T cells also alter ASM contractility has not been addressed. We established an in vitro system to assess the ability of antigen-stimulated CD4(+) T cells to modify contractile responses of the Brown Norway rat trachealis muscle. Our data demonstrated that the unloaded velocity of shortening (Vmax) of ASM was significantly increased upon 24 h co-incubation with antigen-stimulated CD4(+) T cells, while stress did not change. Enhanced Vmax was dependent upon contact between the CD4(+) T cells and the ASM and correlated with increased levels of the fast (+)insert smooth muscle myosin heavy chain isoform. The levels of myosin light chain kinase and myosin light chain phosphorylation were also increased within the muscle. The alterations in mechanics and in the levels of contractile proteins were transient, both declining to control levels after 48 h of co-incubation. More permanent alterations in muscle phenotype might be attainable when several inflammatory cells and mediators interact together or after repeated antigenic challenges. Further studies will await new tissue culture methodologies that preserve the muscle properties over longer periods of time. In conclusion, our data suggest that inflammatory cells promote ASM hypercontractility in airway hyper-responsiveness and asthma.

Regulation of pulmonary inflammation by mesenchymal cells

Pulmonary inflammation and tissue remodelling are common elements of chronic respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and pulmonary hypertension (PH). In disease, pulmonary mesenchymal cells not only contribute to tissue remodelling, but also have an important role in pulmonary inflammation. This review will describe the immunomodulatory functions of pulmonary mesenchymal cells, such as airway smooth muscle (ASM) cells and lung fibroblasts, in chronic respiratory disease. An important theme of the review is that pulmonary mesenchymal cells not only respond to inflammatory mediators, but also produce their own mediators, whether pro-inflammatory or pro-resolving, which influence the quantity and quality of the lung immune response. The notion that defective pro-inflammatory or pro-resolving signalling in these cells potentially contributes to disease progression is also discussed. Finally, the concept of specifically targeting pulmonary mesenchymal cell immunomodulatory function to improve therapeutic control of chronic respiratory disease is considered.

Cross-roads in the lung: immune cells and tissue interactions as determinants of allergic asthma

Allergic asthma is a chronic disease of the lung characterized by underlying Th2- and IgE-mediated inflammation, structural alterations of the bronchial wall, and airway hyperresponsiveness. Initial allergic sensitization and later development of chronic disease are determined by close interactions between lung structural cells and the resident and migratory immune cells in the lung. Epithelial cells play a crucial role in allergic sensitization by directly influencing dendritic cells induction of tolerant or effector T cells and production of type 2 cytokines by innate immune cells. During chronic disease, the bronchial epithelium, stroma, and smooth muscle become structurally and functionally altered, contributing to the perpetuation of tissue remodeling. Thus, targeting tissue-driven pathology in addition to inflammation may increase the effectiveness of asthma treatment.

Airway smooth muscle in asthma: just a target for bronchodilation?

Airway smooth muscle (ASM) has long been recognized as the main cell type responsible for bronchial hyperresponsiveness. It has, thus, been considered as a target for bronchodilation. In asthma, however, there is a complex relationship between ASM and inflammatory cells, such as mast cells and T lymphocytes. Moreover, the increased ASM mass in asthmatic airways is one of the key features of airway remodeling. This article aims to review the main concepts about the 3 possible roles of ASM in asthma: (1) contractile tone, (2) inflammatory response, and (3) remodeling.

OX40/OX40 ligand interactions in T-cell regulation and asthma

The OX40 receptor is preferentially expressed by T cells, and its cognate ligand OX40L is primarily expressed by antigen-presenting cells such as dendritic cells following activation by thymic stromal lymphopoietin (TSLP). TSLP is released by the bronchial epithelium, airway smooth muscle, and some inflammatory cells in response to numerous insults such as allergens, viruses, and physical damage. OX40L is a costimulatory molecule that plays a sentinel role in the adaptive immune response by promoting T helper (Th) 2 polarization of naive T cells within the lymph node. These polarized T cells produce Th2 cytokines such as IL-4, IL-5, and IL-13, which have been implicated particularly in allergic eosinophilic asthma. Animal models have positioned both TSLP and OX40/OX40L as critical in the development of airway inflammation and hyperreactivity. In human disease, there is good evidence that TSLP is upregulated in asthma, but there are limited data to demonstrate overexpression of OX40 or OX40L in disease. Targeting the OX40/OX40L axis or TSLP presents a novel therapeutic strategy that has the potential of modifying the disease process and, therefore, impacting on its natural history. Whether this approach can demonstrate efficacy in established disease rather than at disease onset is unknown. Biologic therapies directed toward OX40/OX40L are in early phases of development, and results from these studies are eagerly awaited.

The pivotal role of airway smooth muscle in asthma pathophysiology

Asthma is characterized by the association of airway hyperresponsiveness (AHR), inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM) in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/load coupling. Beyond its contractile function, ASM is also involved in bronchial inflammation and remodelling. Whereas ASM is a target of the inflammatory process, it can also display proinflammatory and immunomodulatory functions, through its synthetic properties and the expression of a wide range of cell surface molecules. ASM remodelling represents a key feature of asthmatic bronchial remodelling. ASM also plays a role in promoting complementary airway structural alterations, in particular by its synthetic function.

Panax ginseng ameliorates airway inflammation in an ovalbumin-sensitized mouse allergic asthma model

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng (PG) is a medicinal herb that has been used to treat various immune diseases including asthma and COPD. In this study, we investigated the inhibitory mechanism of PG on asthma parameters in mice.

MATERIALS AND METHODS

BALB/c mice were sensitized with 20 μg/200 μl OVA adsorbed on 1.0mg/50 μl aluminum hydroxide gel adjuvant by i.p. injection on days 0 and 14. Mice were then challenged with 5% OVA in PBS to the nose for 30 min once a day for 3 days, from day 20 until day 22, using a nebulizer. PG (20mg/kg) or vehicle was administrated by i.p. injection once a day 10 min before every OVA challenge for 3 days. The recruitment of inflammatory cells into bronchoalveolar lavage fluid or lung tissues was measured. The expression of EMBP, Muc5ac, CD40, and CD40 ligand (CD40L) in lung tissues was investigated. In addition, the cytokines and mitogen activated protein (MAP) kinases were measured by RT-PCR and Western blot.

RESULTS AND CONCLUSIONS

PG restored the expression of EMBP, Muc5ac, CD40, and CD40L, as well as the mRNA and protein levels of interleukin (IL)-1β, IL-4, IL-5, and tumor necrosis factor (TNF)-α. In addition, PG inhibited the numbers of goblet cells and further small G proteins and MAP kinases in bronchoalveolar lavage cells and lung tissues increased in ovalbumin-induced allergic asthma in mice. These results suggest that PG may be used as a therapeutic agent in asthma, based on reductions of various allergic responses.

Rhinovirus infection induces extracellular matrix protein deposition in asthmatic and nonasthmatic airway smooth muscle cells

Airway remodeling, which includes increases in the extracellular matrix (ECM), is a characteristic feature of asthma and is correlated to disease severity. Rhinovirus (RV) infections are associated with increased risk of asthma development in young children and are the most common cause of asthma exacerbations. We examined whether viral infections can increase ECM deposition and whether this increased ECM modulates cell proliferation and migration. RV infection of nonasthmatic airway smooth muscle (ASM) cells significantly increased the deposition of fibronectin (40% increase, n = 12) and perlecan (80% increase, n = 14), while infection of asthmatic ASM cells significantly increased fibronectin (75% increase, n = 9) and collagen IV (15% increase, n = 9). We then treated the ASM cells with the Toll-like receptor (TLR) agonists polyinosinic:polycytidylic acid, imiquimod, and pure RV RNA and were able to show that the mechanism through which RV induced ECM deposition was via the activation of TLR3 and TLR7/8. Finally, we assessed whether the virus-induced ECM was bioactive by measuring the amount of migration and proliferation of virus-naive cells that seeded onto the ECM. Basically, ECM from asthmatic ASM cells induced twofold greater migration of virus-naive ASM cells than ECM from nonasthmatic ASM cells, and these rates of migration were further increased on RV-modulated ECM. Increased migration on the RV-modulated ECM was not due to increased cell proliferation, as RV-modulated ECM decreased the proliferation of virus-naive cells. Our results suggest that viruses may contribute to airway remodeling through increased ECM deposition, which in turn may contribute to increased ASM mass via increased cell migration.

Airway remodeling in asthma: new mechanisms and potential for pharmacological intervention

The chronic inflammatory response within the airways of asthmatics is associated with structural changes termed airway remodeling. This remodeling process is a key feature of severe asthma. The 5-10% of patients with a severe form of the disease account for the higher morbidity and health costs related to asthma. Among the histopathological characteristics of airway remodeling, recent reports indicate that the increased mass of airway smooth muscle (ASM) plays a critical role. ASM cell proliferation in severe asthma implicates a gallopamil-sensitive calcium influx and the activation of calcium-calmodulin kinase IV leading to enhanced mitochondrial biogenesis through the activation of various transcription factors (PGC-1α, NRF-1 and mt-TFA). The altered expression and function of sarco/endoplasmic reticulum Ca(2+) pump could play a role in ASM remodeling in moderate to severe asthma. Additionally, aberrant communication between an injured airway epithelium and ASM could also contribute to disease severity. Airway remodeling is insensitive to corticosteroids and anti-leukotrienes whereas the effect of monoclonal antibodies (the anti-IgE omalizumab, the anti-interleukin-5 mepolizumab or anti-tumor necrosis factor-alpha) remains to be investigated. This review focuses on potential new therapeutic strategies targeting ASM cells, especially Ca(2+) and mitochondria-dependent pathways.

Airway smooth muscle modulation and airway hyper-responsiveness in asthma: new cellular and molecular paradigms

There is growing evidence indicating the existence of a causal relationship between abnormal airway smooth muscle (ASM) function and airway hyper-responsiveness, a poorly understood feature of asthma that can be defined as an excessive bronchospastic response. In recent years, there has been a veritable explosion of articles suggesting that ASM exposed to proasthmatic cytokines can elicit a hyper-responsive state to contractile G-protein-coupled receptor (GPCR) agonists. Aberrant airway responsiveness could result from abnormal calcium signaling, with changes occurring at various levels of GPCR-associated signal transduction. This review presents the latest observations describing novel mechanistic models that could explain the involvement of ASM in airway hyper-responsiveness. This review will discuss the role of ASM in beta(2)-agonist-mediated bronchial hyper-responsiveness and the clinical significance of cell-cell contact between ASM and mast cells recently described to be intimately infiltrated within the ASM tissues in asthmatic patients. The possibility that allergens could trigger airway hyper-responsiveness by directly acting on ASM via activation of immunoglobulin E receptors, FcepsilonRI and FCepsilonRII will also be discussed. These important findings further support the notion that targeting ASM could offer new treatment for many features of asthma, including airway hyper-responsiveness. Future therapeutic intervention includes: the prevention of ASM-inflammatory cell physical and/or functional interaction, the inhibition of Immunoglobulin E receptor-dependent signal transduction, and the abrogation of cytokine-dependent pathways that modulate receptor-associated calcium metabolism.

Airway wall expression of OX40/OX40L and interleukin-4 in asthma

Background:

The costimulatory molecule OX40 and its ligand, OX40L, mediate key aspects of allergic airway inflammation in animal models of asthma, including eosinophilic airway inflammation, airway hyperresponsiveness, and T helper 2 polarization. We sought to examine OX40/OX40L and interleukin (IL)-4 expression in asthma across severities.

Methods:

Bronchial biopsies were obtained from 27 subjects with asthma (mild Global Initiative for Asthma [GINA] 1 [n = 10], moderate GINA 2-3 [n = 7], and severe GINA 4-5 [n = 10]) and 13 healthy controls. The number of OX40⁺, OX40L⁺, IL-4⁺, and IL-4 receptor α (IL-4Rα)⁺ cells in the lamina propria and airway smooth muscle (ASM) bundle and the intensity of IL-4Rα⁺ expression by the ASM were assessed.

Results:

The number of OX40⁺, OX40L⁺, and IL-4⁺ cells in the lamina propria and OX40⁺ and IL-4⁺ cells in the ASM bundle was significantly increased in subjects with mild asthma, but not in those with moderate or severe asthma, compared with healthy controls. In the subjects with asthma, OX40/OX40L expression was positively correlated with the number of eosinophils and IL-4⁺ cells in the lamina propria. The number of IL-4Rα⁺ cells in the lamina propria was significantly increased in moderate-to-severe disease, but not in mild asthma, compared with controls. IL-4Rα expression by the ASM bundle was not different among groups.

Conclusions:

OX40/OX40L expression is increased in the bronchial submucosa in mild asthma, but not in moderate-to-severe disease, and is related to the degree of tissue eosinophilia and IL-4 expression. Whether these costimulatory molecules have a role as targets for asthma requires further investigation.

Expression and function of the inducible costimulator ligand B7-H2 in human airway smooth muscle cells

BACKGROUND

B7-H2 is a ligand for the inducible costimulator (ICOS). The aim of this study was to examine the expression and function of B7-H2 in human airway smooth muscle (ASM) cells and compare them with those of CD40 or OX40 ligand (OX40L).

METHODS

Expression of B7-H2, CD40 and OX40L in ASM cells and their respective counterparts in T cells was analyzed by RT-PCR or flow cytometry. The modulating effect of polyinosinic-polycytidylic acid (poly I:C) on expression of B7-H2, CD40 and OX40L was also examined. The function of these three molecules was evaluated by virtue of adhesion of anti-CD3-activated T cells, IL-6 and IL-8 production and DNA synthesis.

RESULTS

ASM cells constitutively expressed B7-H2, CD40 and OX40L that mediated adhesion of activated T cells expressing ICOS, CD40L and OX40. ASM cells responded to poly I:C with upregulated expression of B7-H2, CD40 and OX40L and displayed enhanced adhesion of activated T cells. Functional analysis performed on untreated ASM cells showed that engagement of B7-H2 with ICOS-Ig clearly induced DNA synthesis, whereas that of CD40 or OX40L with trimeric CD40L or OX40-Ig greatly increased IL-6 and IL-8 production. These responses were enhanced in poly I:C-treated ASM cells.

CONCLUSIONS

The data demonstrate that ASM cells express functionally active B7-H2, CD40 and OX40L and suggest that B7-H2-dependent signaling may play an active role in a proliferative response rather than in cytokine and chemokine production. In addition, the modulation of B7-H2, CD40 and OX40L expression and function by poly I:C may have important implications for the function of virus-infected ASM cells.

Immunopathogenesis of bronchial asthma

Bronchial asthma is a common immune-mediated disorder characterized by reversible airway inflammation, mucus production, and variable airflow obstruction with airway hyperresponsiveness. Allergen exposure results in the activation of numerous cells of the immune system, of which dendritic cells (DCs) and Th2 lymphocytes are of paramount importance. Although the epithelium was initially considered to function solely as a physical barrier, it is now evident that it plays a central role in the Th2-cell sensitization process due to its ability to activate DCs. Cytokines are inevitable factors in driving immune responses. To the list of numerous cytokines already known to be involved in the regulation of allergic reactions, new cytokines were added, such as TSLP, IL-25, and IL-33. IgE is also a central player in the allergic response. The activity of IgE is associated with a network of proteins, especially with its high- and low-affinity Fc receptors. Understanding the cellular and molecular mechanisms of allergic reactions helps us not only to understand the mechanisms of current treatments, but is also important for the identification of new targets for biological intervention. An IgE-specific monoclonal antibody, omalizumab, has already reached the clinic and similar biological agents will surely follow.

CD40 and OX40 ligand are differentially regulated on asthmatic airway smooth muscle

BACKGROUND

CD40 and OX40 Ligand (OX40L) are cell-surface molecules expressed on airway smooth muscle (ASM) that can enhance inflammatory cell activation and survival. The aim of this study was to examine the effect of tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on ASM CD40 and OX40L expression.

METHODS

CD40 and OX40L expression on human ASM cells from asthmatic and nonasthmatic donors following stimulation with TNF-alpha and/or IFN-gamma was measured using cell-surface enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Involvement of signalling pathway was investigated with pharmacological inhibitors. Soluble TNF receptor levels were quantified by ELISA.

RESULTS

Interferon-gamma and TNF-alpha synergistically increased CD40 expression to a greater extent on asthmatic than on nonasthmatic ASM. In contrast, IFN-gamma reduced TNF-alpha-induced OX40L expression to a similar extent in both cell types. TNF-alpha and IFN-gamma induced CD40 via nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription-3 in both cell types and modulated OX40L via NF-kappaB and c-Jun N terminal kinase in nonasthmatic cells. Similar effects on the induction of OX40L in asthmatic cells were seen with NF-kappaB, but these were not statistically significant. The reduced OX40L expression with TNF-alpha and IFN-gamma involved extracellular regulated kinase 1/2 activation.

CONCLUSION

Asthmatic ASM may modulate airway inflammation locally by increasing CD40 and OX40L expression in response to cytokines. IFN-gamma may regulate ASM pro-inflammatory actions by differentially modulating ASM CD40 and OX40L expression.

Pulmonary suppressor of cytokine signaling-1 induced by IL-13 regulates allergic asthma phenotype

RATIONALE

Th2 cytokines play an important role in allergic diseases. These cytokines activate signal transduction pathways, including Janus kinase/signal transducer and activator of transcription (STAT) signaling. Although the suppressor of cytokine signaling (SOCS) family protein, a negative regulator of the Janus kinase/STAT signaling pathway, contributes to helper T cell differentiation during immune responses, the role of SOCS proteins within the structural cells of a target organ has not been clarified in allergy.

OBJECTIVES

To study the local function of SOCS in the development of asthma.

METHODS

We used mouse models of IL-13- and ovalbumin (OVA)-induced allergic airway disease. Airway smooth muscle cells were cultured from patients with asthma.

MEASUREMENTS AND MAIN RESULTS

The administration of IL-13 induced not only airway responses but also SOCS1 expression at the local inflammatory site. The up-regulated SOCS1 markedly suppressed IL-13-dependent STAT6 activation and eotaxin expression and subsequently down-regulated IL-13-induced airway inflammatory responses. The inactivation of SOCS1 induced airway hyperresponsiveness after IL-13 treatment even in hyporesponsive C57BL/6 background mice. In an OVA-induced model of allergic airway disease, allergen exposure up-regulated local SOCS1 expression, and the induction of SOCS1 in the airways attenuated allergen-induced airway responses. Inactivation of IL-13 inhibited SOCS1 induction in a model of allergic airway disease. Interestingly, airway smooth muscle cells from individuals with asthma had impaired up-regulation of SOCS1 after IL-13 stimulation.

CONCLUSIONS

SOCS1 induction by IL-13 in airway structural cells is critical to negatively control allergic airway disease.

STAT2*C related genotypes and allele but not TLR4 and CD40 gene polymorphisms are associated with higher susceptibility for asthma

Objective: Asthma is caused by a complex interaction between multiple genes and environmental factors. Herein we aimed to investigate whether signal transducer and activator of transcription (STAT2), toll-like receptors 4 (TLRs4) and CD40-related polymorphisms are associated with asthma susceptibility.

Design: Children were divided: (1) asthma (n=117); (2) normal controls (n=60). The polymorphisms of STAT2, TLR4 and CD40 polymorphism were analyzed by PCR-RFLP genotyping. Genotypes, allelic frequencies and association of haplotypes in both groups were compared.

Results: STAT2*C related genotypes, but not TLR4 and CD40 polymorphism, are associated with higher susceptibility for asthma. Distributions of STAT2*CC/CG/GG and C/G allele in both groups are: (1) 0/11.1/88.9 % and 5.6/94.4%; (2) 0/1.7/98.3% and 0.8/99.2% (p<0.05). Proportions of TLR4*rs10983755 AA/AG/GG and rs1927914 CC/CT/TT homozygote are: (1) 35.1/8.5/56.4% and 9.4/56.4/34.2%; (2) 35/8.3/56.7% and 16.7/48.3/35% (non-difference). Proportions of CD40*rs1883832 CC/CT/TT, rs3765459 AA/AG/GG, and rs4810485 TT/GT/GG are: (1) 29.9/53/17.1%, 6.8/47.9/45.3 and 18.8/62.4/18.8%; (2) 36.7/41.7/21.6%, 1.6/46.7/ 51.7 and 15/51.7/33.3% (non-difference). Haplotype analyses for TLR4 and CD40 genes revealed their non-association and non-additional effect upon asthma susceptibilities.

Conclusion: STAT2*C related genotypes and alleles are associated with asthma susceptibilities and pathogenesis. There were non-association and non-additional effects of TLR4/CD40 gene polymorphisms and haplotypes upon asthma risk.

The influence of CD4 T-cell subsets on control of CD4 T-cell-mediated graft-versus-host disease

In this study, we tested the effect of different T-cell subpopulations on antigen driven effector cell expansion in lymphopenic hosts, making use of an experimental model of graft-versus-host disease (GVHD). Fluorescence-activated cell sorted (FACS) naïve CD4 T cells from C57BL/6 mice, transferred into lymphopenic F1 (C57BL/6 x BALB/c) Rag-deficient hosts, proliferated extensively and migrated systemically causing acute GVHD within 4 weeks after transfer. Adoptive hosts of CD4 memory T cells on the other hand developed milder symptoms of GVHD with later onset. T-cell expansion and migration to peripheral sites as well as development of GVHD were prevented when naïve T cells were transferred together with CD4(+) CD25(+) T cells, but co-transfer of memory T cells with naïve T cells could not prevent GVHD, although its onset was delayed. OX40, a costimulatory marker that is upregulated at an early time point after T-cell activation and enhances T-cell proliferation, cytokine secretion and survival, was strongly upregulated during GVH responses. Naïve T cells deficient in OX40 expression caused markedly reduced GVH in onset and severity despite some level of expansion in the adoptive host, suggesting an important role of this molecule in the immune pathology of GVHD.

Constitutive and inducible thymic stromal lymphopoietin expression in human airway smooth muscle cells: role in chronic obstructive pulmonary disease

Thymic stromal lymphopoietin (TSLP) is a novel cytokine that triggers dendritic cell-mediated T helper (Th)-2 inflammatory responses. Previous studies have demonstrated that human airway smooth muscle cells (HASMC) play a critical role in initiating or perpetuating airway inflammation by producing chemokines and cytokines. In this study, we first evaluated the expression of TSLP in primary HASMC and investigated how proinflammatory cytokines (TNF-alpha and IL-1beta) and Th-2 cytokines (IL-4, IL-9) regulate TSLP production from HASMC. TSLP mRNA and protein were assessed by real-time RT-PCR, ELISA, and immunofluorescence from primary HASMC cultures. Primary HASMC express constitutive level of TSLP. Incubation of HASMC with IL-1 or TNF-alpha resulted in a significant increase of TSLP mRNA and protein release from HASMC. Furthermore, combination of IL-1beta and TNF-alpha has an additive effect on TSLP release by HASMC. Primary HASMC pretreated with inhibitors of p38 or p42/p44 ERK MAPK, but not phosphatidylinositol 3-kinase, showed a significant decrease in TSLP release on IL-1beta and TNF-alpha treatment. Furthermore, TSLP immunoreactivity was present in ASM bundle from chronic obstructive pulmonary disease (COPD) and to lesser degree in normal subjects. Taken together, our data provide the first evidence of IL-1beta- and TNF-alpha-induced TSLP expression in HASMC via (p38, p42/p44) MAPK signaling pathways. Our results raise the possibility that HASMC may play a role in COPD airway inflammation via TSLP-dependent pathway.

Inflammation of bronchial smooth muscle in allergic asthma

BACKGROUND

Recent observations in asthma suggest that bronchial smooth muscle is infiltrated by inflammatory cells including mast cells. Such an infiltration may contribute to airway remodelling that is partly due to an increase in smooth muscle mass. Whether muscle increase is the result of smooth muscle cell hypertrophy remains controversial and has not been studied by ultrastructural analysis. A morphometric analysis of airway smooth muscle (ASM) was undertaken in asthmatic patients using electron microscopy to examine the interactions between ASM cells and inflammatory cells.

METHODS

ASM specimens were obtained from 14 asthmatic subjects and nine non-asthmatic controls undergoing fibreoptic endoscopy. Inflammatory cell counts were assessed by immunohistochemistry, and ultrastructural parameters were measured using electron microscopy in a blinded fashion on smooth muscle cells and inflammatory cells.

RESULTS

ASM from asthmatic patients was infiltrated by an increased number of mast cells and lymphocytes. Smooth muscle cells and their basal lamina were thicker in asthmatic patients (9.5 (0.8) and 1.4 (0.2) microm) than in controls (6.7 (0.4) and 0.7 (0.1) microm). In asthmatics the extracellular matrix was frequently organised in large amounts between ASM cells. Myofibroblasts within smooth muscle bundles were only observed in asthmatics, some of them displaying a close contact with ASM cells.

CONCLUSION

In asthma, airway myositis is characterised by a direct interaction between ASM cells and mast cells and lymphocytes. Smooth muscle remodelling was present, including cell hypertrophy and abnormal extracellular matrix deposition moulding ASM cells.

Association analysis of CD40 polymorphisms with asthma and the level of serum total IgE

RATIONALE

The CD40 protein plays important roles in cell-mediated and humoral immune responses, especially in immunoglobulin class-switching to IgE.

OBJECTIVES

We tested the association of CD40 polymorphisms with the risk of asthma and the level of serum IgE and investigated the functional effect of associated polymorphisms on the expression of CD40.

METHODS

We identified 17 CD40 single-nucleotide polymorphisms (SNPs) in the Korean population by direct sequencing, and we genotyped 7 of these in 487 subjects with asthma and in 161 normal subjects. Cell-surface expression of CD40 for B-cell lines of various SNP genotypes was measured using flow cytometry. The effects of SNPs in the promoter and 5'-untranslated regions (UTRs) of CD40 were assessed using pGL3 luciferase and enhanced green fluorescent protein (EGFP) reporter systems, respectively.

MEASUREMENTS AND RESULTS

None of the SNPs was associated with asthma risk, but total serum IgE levels were associated with the -580G>A and -1C>T polymorphisms in subjects with asthma (p = 0.007 and 0.005, respectively). The total amount of IgE was highest in the -580A or -1C homozygotes. More CD40 was expressed in B cells with the -1C allele than in those with the -1T allele (p < 0.001). EGFP expression from the CD40 5'-UTR-EGFP construct was higher for the -1C allele than the -1T allele. The -580G>A SNP did not affect promoter activity, even after IFN-gamma stimulation.

CONCLUSIONS

CD40 gene polymorphisms exert a genetic effect on IgE production in patients with asthma through translational regulation of CD40 expression on B cells.

Anti-inflammatory mechanism of simvastatin in mouse allergic asthma model

Statins have anti-inflammatory property and immunomodulatory activity. In this study we aimed to investigate the inhibitory mechanism of simvastatin in allergic asthmatic symptoms in mice. BALB/c mice were sensitized and challenged by ovalbumin to induce asthma. Ovalbumin-specific serum IgE levels were measured by enzyme-linked immunosorbent assay (ELISA), and the recruitment of inflammatory cells into bronchoalveolar lavage fluid or lung tissues was measured by Diff-Quik staining and hematoxylin and eosin (H&E) staining, respectively, the expressions of CD40, CD40 ligand (CD40L), and vascular cell adhesion molecule-1 (VCAM-1) by immunohistochemistry, the mRNA and protein expressions of cytokines in lung tissues by reverse transcriptase-polymerase chain reaction (RT-PCR) or ELISA, epithelial hyperplasia by periodic acid-Schiff (PAS) staining, activities of matrix metalloproteinases (MMPs) by zymography, the activities of small G proteins, mitogen-activated protein (MAP) kinases and nuclear factor-kappa B (NF-kappaB) in bronchoalveolar lavage cells and lung tissues by western blot and EMSA, respectively. Simvastatin reduced ovalbumin-specific IgE level, the number of total inflammatory cells, macrophages, neutrophils, and eosinophils into bronchoalveolar lavage fluid, the expressions of CD40, CD40L or VCAM-1, the mRNA and protein levels of interleukin (IL)-4, IL-13 and tumor necrosis factor (TNF)-alpha, the numbers of goblet cells, activities of MMPs, and further small G proteins, MAP kinases and NF-kappaB activities in bronchoalveolar lavage cells and lung tissues increased in ovalbumin-induced allergic asthma in mice. Our data suggest that simvastatin may be used as a therapeutic agent in asthma, based on reductions of various allergic responses via regulating small G proteins/MAP kinases/NF-kappaB in mouse allergic asthma.

Role of TNFalpha in pulmonary pathophysiology

Tumor necrosis factor alpha (TNFα) is the most widely studied pleiotropic cytokine of the TNF superfamily. In pathophysiological conditions, generation of TNFα at high levels leads to the development of inflammatory responses that are hallmarks of many diseases. Of the various pulmonary diseases, TNFα is implicated in asthma, chronic bronchitis (CB), chronic obstructive pulmonary disease (COPD), acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In addition to its underlying role in the inflammatory events, there is increasing evidence for involvement of TNFα in the cytotoxicity. Thus, pharmacological agents that can either suppress the production of TNFα or block its biological actions may have potential therapeutic value against a wide variety of diseases. Despite some immunological side effects, anti-TNFα therapeutic strategies represent an important breakthrough in the treatment of inflammatory diseases and may have a role in pulmonary diseases characterized by inflammation and cell death.

Functional analysis of the chemokine receptor CCR3 on airway epithelial cells

The function of chemokine receptors on structural cells is only partially known. We previously reported the expression of a functional CCR3 receptor on airway epithelial cells (EC). We speculated that CCR3 might drive wound repair and expression of inflammatory genes in epithelium. The human airway EC lines BEAS-2B, 16-HBE, and primary bronchial EC were used to test the effect of in vitro challenge with the CCR3 ligands CCL11/eotaxin, CCL24/eotaxin-2, or CCL26/eotaxin-3 on 1) wound repair, using an established wound model; 2) cell proliferation and chemotaxis, using specific fluorometric assays; and 3) gene expression, using pathway-specific arrays for inflammatory and profibrotic cytokines, chemokines, and chemokine receptor genes. Agonist specificity was tested by cell pretreatment with an AstraZeneca CCR3 antagonist (10(-8) - 10(-6) M). CCL24 challenge significantly accelerated epithelial wound closure, with similar effects exerted by CCL11 and CCL26. This effect was time dependent, submaximal at 1 nM, and comparable in potency to epidermal growth factor. CCL24 induced a concentration-dependent increase in EC proliferation and chemotaxis, with significant effects observed at 10 nM. The AstraZeneca compound selectively inhibited these CCL24-mediated responses. CCL11 induced the up-regulation of several profibrogenic molecules such as fibroblast growth factor 1 and 5 and of several CC and CXC chemokines. Epithelial immunostaining for CCR3 was stronger in bronchial biopsies of asthmatics displaying marked inflammatory changes than in nondiseased samples. Epithelial CCR3 participates in key functions for wound repair, amplifies the expression of profibrogenic and chemokine transcripts, and appears up-regulated in inflamed asthmatic airways.

A network-based analysis of allergen-challenged CD4+ T cells from patients with allergic rhinitis

We performed a network-based analysis of DNA microarray data from allergen-challenged CD4(+) T cells from patients with seasonal allergic rhinitis. Differentially expressed genes were organized into a functionally annotated network using the Ingenuity Knowledge Database, which is based on manual review of more than 200,000 publications. The main function of this network is the regulation of lymphocyte apoptosis, a role associated with several genes of the tuber necrosis factor superfamily. The expression of TNFRSF4, one of the genes in this family, was found to be 48 times higher in allergen-challenged cells than in diluent-challenged cells. TNFRSF4 is known to inhibit apoptosis and to enhance Th2 proliferation. Examination of a different material of allergen-stimulated peripheral blood mononuclear cells showed a higher number of interleukin-4(+) type 2 CD4(+) T (Th2) cells in patients than in controls (P<0.01), as well as a higher number of non-apoptotic Th2 cells in patients (P<0.01). The number of Th2 cells expressing TNFRSF4, TNFSF7 and TNFRSF1B was also significantly higher in patients. Treatment with anti-TNFSF4 resulted in a significantly decreased number of Th2 cells (P<0.05). A logical inference from all this is that the proliferation of allergen-challenged Th2 cells is associated with a decreased apoptosis of Th2 cells and an increase in TNFRSF4 signalling.

Mast cell migration to Th2 stimulated airway smooth muscle from asthmatics

BACKGROUND

Mast cell microlocalisation within the airway smooth muscle (ASM) bundle is an important determinant of the asthmatic phenotype. We hypothesised that mast cells migrate towards ASM in response to ASM derived chemokines.

METHODS

Primary ASM cultures from subjects with and without asthma were stimulated with interleukin (IL)-1beta, IL-4, and IL-13 alone and in combination. Mast cell chemotaxis towards these ASM supernatants was investigated, and the chemotaxins mediating migration by using specific blocking antibodies for stem cell factor (SCF) and the chemokine receptors CCR3, CXCR1, 3 and 4 as well as the Gi inhibitor pertussis toxin and the tyrosine kinase inhibitor genistein were defined. The concentrations of CCL11, CXCL8, CXCL10, TGF-beta, and SCF in the supernatants were measured and the effect of non-asthmatic ASM supernatants on the mast cell chemotactic activity of asthmatic ASM was examined.

RESULTS

Human lung mast cells and HMC-1 cells migrated towards Th2 stimulated ASM from asthmatics but not non-asthmatics. Mast cell migration was mediated through the combined activation of CCR3 and CXCR1. CCL11 and CXCL8 expression by ASM increased markedly after stimulation, but was similar in those with and without asthma. ASM supernatants from non-asthmatics inhibited mast cell migration towards the asthmatic ASM supernatant.

CONCLUSION

Th2 stimulated ASM from asthmatics is chemotactic for mast cells. Non-asthmatic ASM releases a mediator or mediators that inhibit mast cell migration towards stimulated asthmatic ASM. Specifically targeting mast cell migration into the ASM bundle may provide a novel treatment for asthma.

Increased secretion of leukemia inhibitory factor by immature airway smooth muscle cells enhances intracellular signaling and airway contractility

Airway smooth muscle cells (ASMC) play a major role in airway inflammation, hyperresponsiveness, and obstruction in asthma. However, very little is known regarding the relation between inflammatory mediators and cytokines and immature ASMC. The aim of this study was to evaluate 1) the secretion of leukemia inhibitory factor (LIF) (an IL-6 family neurotrophic cytokine) by ASMC; 2) intracellular calcium concentration ([Ca(2+)](i)) signaling; and 3) the effect of LIF on mast cell chemotaxis and rat airway contractility. Immature and adult human ASMC were cultured. ELISA and real-time PCR were performed to assess LIF protein secretion and mRNA production, [methyl-(3)H]thymidine incorporation to quantify ASMC DNA synthesis, a Boyden chamber to evaluate the effect of LIF on mast cell chemotaxis, microspectroflurimetry using indo-1 (at baseline and after stimulation bradykinin, U-46619, histamine, and acetylcholine, in the presence or absence of LIF or TNF-alpha) for [Ca(2+)](i) signaling, and isolated rat pup tracheae to determine the effect of LIF on airway contractility to ACh. TNF-alpha-stimulated immature ASMC produce more LIF mRNA and protein than adult ASMC, although this cytokine induces a moderate increase in DNA synthesis (+20%) in adult ASMC only. Human recombinant LIF exerts no chemotactic effect on human mast cells. In immature ASMC, ACh-induced [Ca(2+)](i) response was enhanced twofold after incubation with LIF, whereas TNF-alpha increased the [Ca(2+)](i) to U-46619 threefold. In TNF-alpha-exposed adult ASMC, [Ca(2+)](i) responses to ACh were of greater magnitude (sixfold increase) than in immature ASMC. Human recombinant LIF increased contractility to ACh by 50% in immature, isolated rat tracheae. Stimulated immature human ASMC greatly secrete LIF, thus potentially contributing to neuroimmune airway inflammation and subsequent remodeling. Increased LIF secretion enhances airway reactivity and [Ca(2+)](i) signaling.

The costimulatory molecules CD80, CD86 and OX40L are up-regulated in Aspergillus fumigatus sensitized mice

Aspergillus fumigatus (Af) is a fungus associated with allergic bronchopulmonary aspergillosis (ABPA) and other allergic diseases. Immune responses in these diseases are due to T and B cell responses. T cell activation requires both Af-specific engagement of the T-cell-receptor as well as interaction of antigen independent costimulatory molecules including CD28-CD80/CD86 and OX40-OX40L interactions. Since these molecules and their interactions have been suggested to have a potential involvement in the pathogenesis of ABPA, we have investigated their role in a model of experimental allergic aspergillosis. BALB/c mice were primed and sensitized with Af allergens, with or without exogenous IL-4. Results showed up-regulation of both CD86 and CD80 molecules on lung B cells from Af-sensitized mice (79% CD86+ and 24% CD80+) and Af/rIL-4-treated mice (90% CD86+ and 24% CD80+) compared to normal controls (36% and 17%, respectively). Lung macrophages in Af-sensitized mice treated or not with IL-4 showed enhanced expression of these molecules. OX40L expression was also up-regulated on lung B cells and macrophages from both Af-sensitized and Af/rIL-4 exposed mice as compared to normal controls. All Af-sensitized animals showed peripheral blood eosinophilia, enhanced total serum IgE and allergen-specific IgG1 antibodies and characteristic lung inflammation. The up-regulation of CD80, CD86 and OX40L molecules on lung B cells and macrophages from Af-allergen exposed mice suggests a major role for these molecules in the amplification and persistence of immunological and inflammatory responses in ABPA.