TH2 cytokine expression in bronchoalveolar lavage fluid T lymphocytes and bronchial submucosa is a feature of asthma and eosinophilic bronchitis

Sputum Transcriptomics Reveals FCN1+ Macrophage Activation in Mild Eosinophilic Asthma Compared to Non-Asthmatic Eosinophilic Bronchitis

PURPOSE

Eosinophilic asthma (EA) and non-asthmatic eosinophilic bronchitis (EB) share similar eosinophilic airway inflammation. Unlike EA, EB did not present airway hyperresponsiveness or airflow obstruction. We aimed to compare the mechanism underlying the different manifestations between EA and EB via sputum transcriptomics analysis.

METHODS

Induced-sputum cells from newly physician-diagnosed EA, EB patients, and healthy controls (HCs) were collected for RNA sequencing.

RESULTS

Bulk RNA sequencing was performed using sputum cells from patients with EA (n = 18), EB (n = 15) and HCs (n = 28). Principal component analysis revealed similar gene expression patterns in EA and EB. The most differentially expressed genes in EB compared with HC were also shared by EA, including IL4, IL5 IL13, CLC, CPA3, and DNASE1L3. However, gene set enrichment analysis showed that the signatures regulating macrophage activation were enriched in EA compared to EB. Sputum cells were profiled using single-cell RNA sequencing. FABP4+ macrophages, SPP1+ macrophages, FCN1+ macrophages, dendritic cells, T cells, B cells, mast cells, and epithelial cells were identified based on gene expression profiling. Analysis of cell-cell communication revealed that interactions between FCN1+ macrophages and other cells were higher in EA than in EB. A wealth of transforming growth factor beta (TGF-β) and vascular endothelial growth factor (VEGF) interactions between FCN1+ macrophages and other cells have been shown in EA. The gene expression levels of EREG, TGFBI, and VEGFA in FCN1+ macrophages of EA were significantly higher than those of EB. Furthermore, signatures associated with the response to TGF-β, cellular response to VEGF stimulus and developmental cell growth were enriched in FCN1+ macrophages of EA compared to those of EB.

CONCLUSIONS

FCN1+ macrophage activation associated with airway remodeling processes was upregulated in EA compared to that in EB, which may contribute to airway hyperresponsiveness and airflow obstruction.

T helper 2 cells in asthma

Allergic asthma is among the most common immune-mediated diseases across the world, and type 2 immune responses are thought to be central to pathogenesis. The importance of T helper 2 (Th2) cells as central regulators of type 2 responses in asthma has, however, become less clear with the discovery of other potent innate sources of type 2 cytokines and innate mediators of inflammation such as the alarmins. This review provides an update of our current understanding of Th2 cells in human asthma, highlighting their many guises and functions in asthma, both pathogenic and regulatory, and how these are influenced by the tissue location and disease stage and severity. It also explores how biologics targeting type 2 immune pathways are impacting asthma, and how these have the potential to reveal hitherto underappreciated roles for Th2 cell in lung inflammation.

Integrated Network Pharmacology and Gut Microbiota Analysis to Explore the Mechanism of Sijunzi Decoction Involved in Alleviating Airway Inflammation in a Mouse Model of Asthma

Background

Asthma is a chronic inflammatory disease of the airways with recurrent attacks, which seriously affects the patients' quality of life and even threatens their lives. The disease can even threaten the lives of patients. Sijunzi decoction (SJZD), a classical Chinese medicine formula with a long history of administration, is a basic formula used for the treatment of asthma and demonstrates remarkable efficacy. However, the underlying mechanism has not been elucidated.

Materials and Methods

We aimed to integrate network pharmacology and intestinal flora sequencing analysis to study the mechanism of SJZD in the treatment of allergic asthmatic mice. The active compounds of SJZD and their asthma-related targets were predicted by various databases. We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to identify potentially relevant pathways for target genes. Furthermore, the active compound-target and target-signaling pathway network maps were constructed by using Cytoscape 3.8.2. These results were combined with those of the intestinal flora sequencing analysis to study the influence of SJZD on airway inflammation in allergic asthmatic mice.

Result

We obtained 137 active compounds from SJZD and associated them with 1445 asthma-related targets acquired from the databases. A total of 109 common targets were identified. We visualized active compound-target and target-signaling pathway network maps. The pathological analysis and inflammation score results suggested that SJZD could alleviate airway inflammation in asthmatic mice. Sequencing analysis of intestinal flora showed that SJZD could increase the relevant abundance of beneficial bacterial genus and maintain the balance of the intestinal flora. The core toll-like receptor (TLR) signaling pathway was identified based on network pharmacology analysis, and the important role TLRs play in intestinal flora and organismal immunity was also recognized. The analysis of the correlation between environmental factors and intestinal flora revealed that beneficial bacterial genera were negatively correlated with TLR2 and positively correlated with the TLR7 expression. Furthermore, they were positively correlated with IFN-γ and IL-10 levels and negatively correlated with IL-4 and IL-17 levels.

Conclusion

SJZD alleviated the airway inflammation state in asthmatic mice. The findings suggest that increasing the relevant abundance of beneficial intestinal bacteria in mice with asthma, regulating intestinal flora, interfering with the level of TLR2 and TLR7 expression to adjust the secretion of inflammatory factors, and alleviating asthmatic airway inflammation may be the possible mechanism involved in the treatment of asthma by SJZD, providing a basis for further studies on SJZD.

Eosinophil Progenitors in Patients With Non-Asthmatic Eosinophilic Bronchitis, Eosinophilic Asthma, and Normal Controls

Objective

This study aims to explore the potential of in situ airway differentiation of eosinophil progenitors (EoPs) and hematopoietic progenitor cells (HPCs) in sputum and peripheral blood from patients with non-asthmatic eosinophilic bronchitis (NAEB), eosinophilic asthma (EA), and healthy controls (HC).

Methods

Using flow cytometry, we enumerated sputum and blood HPCs and EoPs in patients with NAEB (n=15), EA (n=15), and HC (n=14) at baseline. Patients with NAEB and EA were then treated for 1 month with budesonide (200 μg, bid) or budesonide and formoterol (200/6 μg, bid), respectively. HPCs and EoPs in both compartments were re-evaluated.

Results

At baseline, NAEB and EA both had significantly greater numbers of sputum but not blood HPCs and EoPs (p<0.05) compared to HC. There were no differences between NAEB and EA. After 1 month of inhaled corticosteroid (ICS) treatment, NAEB patients showed a significant improvement in cough symptoms, but the attenuation of sputum HPC and EoP levels was not significant.

Conclusions

NAEB patients have increased airway levels of HPCs and EoPs. One-month treatment with ICS did not fully suppress the level of EoPs in NAEB. Controlling in situ airway differentiation of EoPs may control airway eosinophilia and provide long-term resolution of symptoms in NAEB.

Melatonin antagonizes ozone-exacerbated asthma by inhibiting the TRPV1 channel and stabilizing the Nrf2 pathway

Over the past few years, ozone has been identified as a potential risk factor for exacerbating asthma. However, few attempts have been made to prevent the progression of ozone-exacerbated asthma. This study investigated the attenuating effects of melatonin on ozone-aggravated allergic asthma, and explored the changes to the transient receptor potential vanilloid 1 (TRPV1)-nuclear factor erythroid-derived 2-related factor 2 (Nrf2) pathway associated with melatonin treatment. The levels of TRPV1 and calcitonin gene-related peptides (CGRP) in lung tissue were detected by immunohistochemistry, western blot, and enzyme-linked immunosorbent assay (ELISA). The Nrf2 signaling involved proteins and mRNA were evaluated by western blot and RT-qPCR. The change of Immunoglobulin E (IgE) and T helper (Th) 2 and Th17 cytokines in serum and bronchoalveolar lavage fluid (BALF) was determined by ELISA. Recruitment of inflammatory cells in BALF, histopathological changes, and airway hyperresponsiveness (AHR) were also determined in lung tissues. Our results indicated that melatonin treatment significantly reduced oxidative stress, as indicated by levels of glutathione (GSH), malonaldehyde (MDA), and 8-hydroxy-2-deoxyguanosine (8-OH-dG). Moreover, ozone-exacerbated asthma symptoms, such as inflammatory cell infiltration, levels of serum immunoglobulin, Th2 and Th17 cytokines in BALF, obvious changes in lung histology, and AHR, were all ameliorated by melatonin treatment. Interestingly, melatonin not only markedly decreased the protein levels of TRPV1 and CGRP, but also enhanced the expression of Nrf2, quinone oxidoreductase-1 (NQO-1), and heme oxygenase-1 (HO-1). Taken together, our results demonstrate that melatonin administration could antagonize ozone-exacerbated asthma by inhibiting the TRPV1 channel and stabilizing the Nrf2 pathway.

An initial assessment of the involvement of transglutaminase2 in eosinophilic bronchitis using a disease model developed in C57BL/6 mice

The detailed pathogenesis of eosinophilic bronchitis (EB) remains unclear. Transglutaminase 2 (TG2) has been implicated in many respiratory diseases including asthma. Herein, we aim to assess preliminarily the relationship of TG2 with EB in the context of the development of an appropriate EB model through ovalbumin (OVA) sensitization and challenge in the C57BL/6 mouse strain. Our data lead us to propose a 50 μg dose of OVA challenge as appropriate to establish an EB model in C57BL/6 mice, whereas a challenge with a 400 μg dose of OVA significantly induced asthma. Compared to controls, TG2 is up-regulated in the airway epithelium of EB mice and EB patients. When TG2 activity was inhibited by cystamine treatment, there were no effects on airway responsiveness; in contrast, the lung pathology score and eosinophil counts in bronchoalveolar lavage fluid were significantly increased whereas the cough frequency was significantly decreased. The expression levels of interleukin (IL)-4, IL-13, IL-6, mast cell protease7 and the transient receptor potential (TRP) ankyrin 1 (TRPA1), TRP vanilloid 1 (TRPV1) were significantly decreased. These data open the possibility of an involvement of TG2 in mediating the increased cough frequency in EB through the regulation of TRPA1 and TRPV1 expression. The establishment of an EB model in C57BL/6 mice opens the way for a genetic investigation of the involvement of TG2 and other molecules in this disease using KO mice, which are often generated in the C57BL/6 genetic background.

Narrative Review: how long should patients with cough variant asthma or non-asthmatic eosinophilic bronchitis be treated?

The causes of chronic cough can be categorized into eosinophilic and noneosinophilic disorders, and approximately 30% to 50% of people with chronic cough have eosinophilic airway inflammation, the presence of which can be confirmed by sputum eosinophilia or elevated exhaled nitric-oxide levels. Cough variant asthma (CVA) is a phenotype of asthma which lacks wheezing or dyspnea, and consistently one of the most common causes of chronic cough worldwide. CVA and non-asthmatic eosinophilic bronchitis (NAEB) shares common feature such as chronic dry cough, eosinophilic inflammation, and development of chronic airflow obstruction (CAO) and asthma in a subset of patients. The distinctive characteristic of these conditions is the presence of airway hyperresponsiveness in CVA but not in NAEB. Coughing is responsive to bronchodilators such as beta-agonists in CVA, but such feature has not been clarified in NAEB. Inhaled corticosteroids (ICSs) are the first-line treatment, and leukotriene receptor antagonists are also effective, in patients with both CVA and NAEB. This review will give an outline of clinical and physiological features, and prognosis and its determinants of CVA and EBNA. Further, the rationale and evidence, despite limited, for the need of long-term treatment will be discussed. The development of airway remodeling due to mechanical stress to the airways exerted by long-standing coughing will also be discussed.

IL-4Rα blockade reduces influenza-associated morbidity in a murine model of allergic asthma

Background

Asthma was identified as the most common comorbidity in hospitalized patients during the 2009 H1N1 influenza pandemic. We determined using a murine model of allergic asthma whether these mice experienced increased morbidity from pandemic H1N1 (pH1N1) viral infection and whether blockade of interleukin-4 receptor α (IL-4Rα), a critical mediator of T_h2 signalling, improved their outcomes.

Methods

Male BALB/c mice were intranasally sensitized with house dust mite antigen (Der p 1) for 2 weeks; the mice were then inoculated intranasally with a single dose of pandemic H1N1 (pH1N1). The mice were administered intraperitoneally anti-IL-4Rα through either a prophylactic or a therapeutic treatment strategy.

Results

Infection with pH1N1 of mice sensitized to house dust mite (HDM) led to a 24% loss in weight by day 7 of infection (versus 14% in non-sensitized mice; p < .05). This was accompanied by increased viral load in the airways and a dampened anti-viral host responses to the infection. Treatment of HDM sensitized mice with a monoclonal antibody against IL-4Rα prior to or following pH1N1 infection prevented the excess weight loss, reduced the viral load in the lungs and ameliorated airway eosinophilia and systemic inflammation related to the pH1N1 infection.

Conclusion

Together, these data implicate allergic asthma as a significant risk factor for H1N1-related morbidity and reveal a potential therapeutic role for IL-4Rα signalling blockade in reducing the severity of influenza infection in those with allergic airway disease.

Dendritic cell-CD4+ T cell interaction: The differential role of IL-4/IL-13 in serum IgE levels in house dust mite allergic patients

Allergic asthma is a chronic airway inflammatory disorder triggered by inhalant allergens. Interleukin (IL)-4 and IL-13 play a main role in the generation of T helper cell type 2 (Th2) immune response, induction of immunoglobulin E (IgE) synthesis and persistence of airway inflammation. The aim of the present study was to investigate the influence of Dermatophagoides pteronyssinus allergen Der p 1, the major allergen of house dust mite, on the synthesis of IL-4 and IL-13 by monocyte-derived dendritic cells (DCs) and naive CD4+ T cells cocultured with DCs, as well as their role in the production of serum IgE, in house dust mite (HDM) allergic patients. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood of patients allergic to HDM and healthy donors and incubated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 to generate immature DCs. The obtained cells were stimulated for 24 h with Der p 1 to induce DC maturation, washed, and afterwards cocultured for 24 h with autologous naive CD4+ T cells. Culture supernatants were harvested for IL-4, IL-13 and IFN-γ level measurements. DCs stimulation with Der p 1 induced higher synthesis of IL-4 and IL-13 in HDM allergic patients, compared to healthy donors. The allergic group showed significant correlation between IL-13 production by Der p 1-pulsed DCs, and total serum IgE and IL-4 production of the same cells and Der p-specific IgE. To conclude, IL-4 and IL-13 are critically related to the regulation of serum IgE production in patients with allergic asthma. The relevance of these two cytokines in the pathophysiology of Th2 asthma endotype makes them an appropriate target in its management.

Mesenchymal Stem Cells in Asthma

Asthma is one of the worldwide respiratory health problem that affect children and adult. Current treatment strategies such as conventional and allergen immunotherapy still fall behind. Mesenchymal stem cells (MSCs) have wide regenerative capacity and immunoregulatory activity with their wide range of secretions and contact dependent manner. In this review, we focus on the current treatment strategies for asthma and MSCs as a new therapeutic tool.

Duration of treatment with inhaled corticosteroids in nonasthmatic eosinophilic bronchitis: a randomized open label trial

BACKGROUND

Nonasthmatic eosinophilic bronchitis (NAEB) responds well to inhaled corticosteroids (ICS), while recurrence is common after discontinuing treatment. There are no data available to show whether treatment duration of ICS in patients with NAEB is related to recurrence. We aim to evaluate the effect of different duration of treatment with ICS on relapse of NAEB.

METHODS

A total of 101 patients with NAEB were recruited to the open label, randomized, parallel-group trial. Patients were randomized to receive 1-month, 2-month, or 4-month treatment with inhaled budesonide (200 μg, twice daily). Sputum induction, cough visual analogue scale (VAS), and cough symptom score (CSS) were conducted at baseline and after completion of treatment. The patients were followed up for 1 year after treatment. The primary outcome was the relapse rate of NAEB in 1 year.

RESULTS

ICS significantly decreased cough VAS, CSS, and sputum eosinophilia among these groups. There were no statistically significant between-group differences in cough VAS, CSS scores, and sputum eosinophil counts at the end of treatment, and no significant between-group differences in those changes from baseline to post-treatment. Significantly, more participants in the 1-month treatment group experienced a recurring episode of NAEB than those in the 3-month treatment group (41.9% versus 12.0%, p = 0.0137) at 1-year follow-up. The 2-month treatment group showed a lower tendency, with a relapse rate of 20.0% (p = 0.0644).

CONCLUSIONS

Our results suggest that inhaled corticosteroids should be administrated for at least 2 months to reduce the relapse of NAEB.

CLINICAL TRIAL REGISTRATION

The study was registered on ClinicalTrials.gov (NCT02002715). The reviews of this paper are available via the supplemental material section.

Outside-in hypothesis revisited: The role of microbial, epithelial, and immune interactions

OBJECTIVE

Our understanding of the origin of allergic diseases has increased in recent years, highlighting the importance of microbial dysbiosis and epithelial barrier dysfunction in affected tissues. Exploring the microbial-epithelial-immune crosstalk underlying the mechanisms of allergic diseases will allow the development of novel prevention and treatment strategies for allergic diseases.

DATA SOURCES

This review summarizes the recent advances in microbial, epithelial, and immune interactions in atopic dermatitis, allergic rhinitis, chronic rhinosinusitis, and asthma.

STUDY SELECTIONS

We performed a literature search, identifying relevant recent primary articles and review articles.

RESULTS

Dynamic crosstalk between the environmental factors and microbial, epithelial, and immune cells in the development of atopic dermatitis, allergic rhinitis, chronic rhinosinusitis, and asthma underlies the pathogenesis of these diseases. There is substantial evidence in the literature suggesting that environmental factors directly affect barrier function of the epithelium. In addition, T-helper 2 (T_H2) cells, type 2 innate lymphoid cells, and their cytokine interleukin 13 (IL-13) damage skin and lung barriers. The effects of environmental factors may at least in part be mediated by epigenetic mechanisms. Histone deacetylase activation by type 2 immune response has a major effect on leaky barriers and blocking of histone deacetylase activity corrects the defective barrier in human air-liquid interface cultures and mouse models of allergic asthma with rhinitis. We also present and discuss a novel device to detect and monitor skin barrier dysfunction, which provides an opportunity to rapidly and robustly assess disease severity.

CONCLUSION

A complex interplay between environmental factors, epithelium, and the immune system is involved in the development of systemic allergic diseases.

CD8+ Tc2 cells: underappreciated contributors to severe asthma

The complexity of asthma is underscored by the number of cell types and mediators implicated in the pathogenesis of this heterogeneous syndrome. Type 2 CD4⁺ T-cells (Th2) and more recently, type 2 innate lymphoid cells dominate current descriptions of asthma pathogenesis. However, another important source of these type 2 cytokines, especially interleukin (IL)-5 and IL-13, are CD8⁺ T-cells, which are increasingly proposed to play an important role in asthma pathogenesis, because they are abundant and are comparatively insensitive to corticosteroids. Many common triggers of asthma exacerbations are mediated via corticosteroid-resistant pathways involving neutrophils and CD8⁺ T-cells. Extensive murine data reveal the plasticity of CD8⁺ T-cells and their capacity to enhance airway inflammation and airway dysfunction. In humans, Tc2 cells are predominant in fatal asthma, while in stable state, severe eosinophilic asthma is associated with greater numbers of Tc2 than Th2 cells in blood, bronchoalveolar lavage fluid and bronchial biopsies. Tc2 cells strongly express CRTH2, the receptor for prostaglandin D2, the cysteinyl leukotriene receptor 1 and the leukotriene B4 receptor. When activated, these elicit Tc2 cell chemotaxis and production of chemokines and type 2 and other cytokines, resulting directly or indirectly in eosinophil recruitment and survival. These factors position CD8⁺ Tc2 cells as important and underappreciated effector cells contributing to asthma pathogenesis. Here, we review recent advances and new insights in understanding the pro-asthmatic functions of CD8⁺ T-cells in eosinophilic asthma, especially corticosteroid-resistant asthma, and the molecular mechanisms underlying their pathologic effector function.

Alongside Th2 and ILC2 cells, CD8⁺ T-cells are a cellular source of type 2 cytokines. We review recent findings and insights into the pathologic effector functions of type 2 CD8⁺ T-cells in eosinophilic asthma, especially steroid-resistant disease.http://bit.ly/2KbVGL2

Therapeutic Potential of Morin in Ovalbumin-induced Allergic Asthma Via Modulation of SUMF2/IL-13 and BLT2/NF-kB Signaling Pathway

BACKGROUND

Allergic asthma is a chronic immune-inflammatory disorder, characterized by airway inflammation and airway hyperresponsiveness (AHR). Morin is a natural flavonoid reported to exhibit inhibitory action against IgE-mediated allergic response.

AIM

To determine the efficacy of murine model of ovalbumin (OVA)-induced AHR inhibition by morin and decipher the molecular mechanism involved.

MATERIALS AND METHODS

Sprague-Dawley rats were sensitized and challenged with OVA to induce AHR. Rats received treatment with morin (10, 30 and 100 mg/kg, p.o.) for the next 28 days.

RESULTS

Morin (30 and 100 mg/kg) significantly and dose-dependently attenuated (p < 0.01 and p < 0.001) OVA-induced alterations in pulse oxy and lung function test, increased bronchoalveolar lavage fluid cell counts, elevated total protein and albumin levels in serum, BALF, and lungs, increased serum total and OVA-specific IgE levels and, elevated oxidative stress levels in the lung. RT-PCR analysis revealed that morin treatment (30 and 100 mg/kg) significantly (p < 0.001) up-regulated SUMF2 mRNA expression in lungs whereas mRNA expressions of BLT2, NF-κB, and Th2-cytokine (TNF-α, IL-1β, IL-4, IL-6, and IL-13) were down-regulated significantly and dose-dependently (p < 0.01 and p < 0.001). Also, histologic and ultrastructural studies showed that morin significantly inhibited (p < 0.001) OVAinduced perivascular and peribranchial inflammatory infiltration and interstitial fibrosis.

CONCLUSION

Morin exhibited inhibitory effect against OVA-induced allergic asthma by activation of SUMF2 which impeded IL-13 expression and in turn attenuated Th2-cytokines, BLT2, NF-κB, and IgE levels to ameliorate AHR. Thus, our findings suggested that morin could be considered as a potential alternative therapeutic agent for the management of allergic asthma.

Relationship between various cytokines implicated in asthma

Asthma is a complex disorder involving immunologic, environmental, genetic and other factors. Today, asthma is the most common disease encountered in clinical medicine in both children and adults worldwide. Asthma is characterized by increased responsiveness of the tracheobronchial tree resulting in chronic swelling and inflammation of the airways recognized to be controlled by the T-helper 2 (Th2) lymphocytes, which secrete cytokines to increase the production of IgE by B cells. There are many cytokines implicated in the development of the chronic inflammatory processes that are often observed in asthma. Ultimately, these cytokines cause the release of mediators such as histamine and leukotrienes (LT), which in turn promote airway remodeling, bronchial hyperresponsiveness and bronchoconstriction. The CD4⁺ T-lymphocytes from the airways of asthmatics express a panel of cytokines that represent the Th2 cells. The knowledge derived from numerous experimental and clinical studies have allowed physicians and scientists to understand the normal functions of these cytokines and their roles in the pathogenesis of asthma. The main focus of this review is to accentuate the relationship between various cytokines implicated in human asthma. However, some key findings from animal models will be highlighted to support the discoveries from clinical studies.

Increased Sputum IL-17A Level in Non-asthmatic Eosinophilic Bronchitis

BACKGROUND

Non-asthmatic eosinophilic bronchitis (NAEB) is one common cause of chronic cough which is characterized as airway eosinophilic inflammation like asthma but lack of airway hyper-responsiveness. Previous studies showed that Th2-pathway plays a role in NAEB, but the role of non-Th2 pathway in mechanism of NAEB remains unknown. Recently, IL-17A, a Th17-pathway cytokine, has been demonstrated to be involved in asthma development. However, the relationship between Th17-pathway and NAEB is unknown.

METHODS

We aim to assess the airway level of IL-17A in the subjects with NAEB. Relationships between the IL-17A level and airway function in NAEB or asthma are also observed. We measured IL-17A concentrations in the sputum supernatant from 12 subjects with EB, 16 subjects with asthma [9 eosinophilic asthmatic (EA) and 7 non-eosinophilic asthmatic (NEA) according to the sputum eosinophil ≥ 3%], and 9 healthy control subjects.

RESULTS

Increasing IL-17A level was found in NAEB group (29.65 ± 8.13 pg/ml), EA group (32.45 ± 3.22 pg/ml), and NEA group (29.62 ± 6.91 pg/ml) compared with the healthy control group (17.05 ± 10.30 pg/ml) (P < 0.05, P < 0.01, P < 0.05, respectively). The sputum IL-17A level was correlated with FENO (r = 0.44, P < 0.01), FEV1/FVC% (r = - 0.38, P < 0.05), MMEF%pred (r = - 0.34, P < 0.05), and sputum neutrophil% (r = 0.33, P < 0.05) in total.

CONCLUSION

Th17-pathway may play a role not only in asthmatics, but also in subjects with NAEB, as reflected by increasing IL-17A concentrations in sputum supernatant.

Fra2 Overexpression in Mice Leads to Non-allergic Asthma Development in an IL-13 Dependent Manner

Background: Asthma is a complex chronic inflammatory disease characterised by airway inflammation, remodelling and hyperresponsiveness (AHR). Members of the AP-1 transcription factor family play important roles in the activation of the immune system and the control of cellular responses; however, their role in the development of asthma has not been well studied. We aimed to investigate the role of the lesser known AP-1 family member, Fra2 in experimental asthma.

Methods: Phenotypic characterisation and gene expression profiling was performed on Fra2 (TG) overexpressing and wild-type mice. The efficacy of therapeutic interventions in regulating the Fra2 phenotype was determined.

Results: Transcriptional profiling of TG mice revealed a high abundance of regulated genes associated with airway remodelling, inflammation and mucus production. A concomitant increase in peribronchial collagen deposition, smooth muscle thickening and mucus production was observed. TG mice possessed increased inflammatory infiltration in the lung, predominantly consisting of eosinophils and T-cells and elevated expression of Th2 cytokines and eotaxin. Furthermore, TG mice possessed severe AHR in response to increasing doses of methacholine. Glucocorticoid treatment led to a partial improvement of the asthma phenotype, whereas blockade of IL-13 via neutralising antibodies ameliorated AHR and mucus production, but had no effect on collagen deposition.

Conclusion: We here describe a novel model for non-allergic asthma that does not require the application of exogenous allergens, which mimics several key features of the disease, such as airway inflammation, remodelling and hyperresponsiveness. Fra2 may represent a key molecule coordinating multiple aspects of asthma pathogenesis.

Microbial Insights into Asthmatic Immunopathology. A Forward-Looking Synthesis and Commentary

Asthma is an aberrant inflammatory condition of the airways affecting approximately 1 in 10 children in affluent countries. An increasing body of evidence suggests that microbial exposures during a "critical window" of development in early life play a central role in determining future asthma susceptibility. However, like the disease itself, considerable heterogeneity exists among studies in which researchers have investigated the associations between particular microbial taxa and asthma immunology. As our understanding of asthmatic pathology evolves to enable clearer definition of asthma endotypes, it will be important to consider the impact of various environmental factors on each endotype. Given the strong evidence in support of the hypothesis that early-life microbial exposures predict later disease states such as asthma, consideration of these endotypes when establishing experimental outcomes in epidemiological studies could allow for increased precision when determining exposure-outcome associations and engaging in more focused follow-up mechanistic investigations.

Low Dose Carbon Black Nanoparticle Exposure Does Not Aggravate Allergic Airway Inflammation in Mice Irrespective of the Presence of Surface Polycyclic Aromatic Hydrocarbons

Exposure to exogenous noxae, such as particulate matter, can trigger acute aggravations of allergic asthma—a chronic inflammatory airway disease. We tested whether Carbon Black nanoparticles (CBNP) with or without surface polycyclic aromatic hydrocarbons (PAH) aggravate an established allergic airway inflammation in mice. In an ovalbumin mouse model, Printex^®90 (P90), P90 coated with benzo[a]pyrene (P90-BaP) or 9-nitroanthracene (P90-9NA), or acetylene soot exhibiting a mixture of surface PAH (AS-PAH) was administered twice (70 µL, 100 µg/mL) during an established allergic airway inflammation. We analyzed the immune cell numbers and chemokine/cytokine profiles in bronchoalveolar lavages, the mRNA expressions of markers for PAH metabolism (Cyp1a1, 1b1), oxidative stress (HO-1, Gr, Gpx-3), inflammation (KC, Mcp-1, IL-6, IL-13, IL-17a), mucin synthesis (Muc5ac, Muc5b), the histology of mucus-producing goblet cells, ciliary beat frequency (CBF), and the particle transport speed. CBNP had a comparable primary particle size, hydrodynamic diameter, and ζ-potential, but differed in the specific surface area (P90 > P90-BaP = P90-9NA = AS-PAH) and surface chemistry. None of the CBNP tested increased any parameter related to inflammation. The unmodified P90, however, decreased the tracheal CBF, decreased the Muc5b in intrapulmonary airways, but increased the tracheal Muc5ac. Our results demonstrated that irrespective of the surface PAH, a low dose of CBNP does not acutely aggravate an established allergic airway inflammation in mice.

Effects of ozone repeated short exposures on the airway/lung inflammation, airway hyperresponsiveness and mucus production in a mouse model of ovalbumin-induced asthma

OBJECTIVE

The purpose of this study is to explore the influence of ozone repeated short exposures on airway/lung inflammation, airway hyperresponsiveness (AHR) and airway hypersecretion in ovalbumin (OVA) sensitized/challenged asthmatic mouse model.

METHODS

OVA sensitization was performing by intraperitoneal injection. Ozone exposures (3ppm for 3hours) were given one hour after aerosolized OVA challenges (once every other day, 4 times totally). Methacholine (MCH) bronchial provocation tests, Liu's staining of BALF cell smears, hematoxylin-eosin (HE) staining and Periodic Acid-Schiff (PAS) staining of lung tissue were performed. Interleukins (ILs; IL-4, IL-13, IL-1β, and IL-18) protein (ELISA) and mRNA expression levels (RT-qPCR) in murine lung, 8-hydroxy-2'-deoxyguanosine (8-OHdG, ELISA), malondialdehyde (MDA, thiobarbituric acid assay), reduced glutathione (GSH, spectrophotometric method) in bronchoalveolar lavage fluid (BALF), and GSH1 mRNA relative expression levels (RT-qPCR) in lung tissue were analyzed.

RESULT

Repeated ozone exposures down-regulated the AHR to MCH in mice undergoing OVA sensitization and challenge, however not all parameters associated with asthma were decreased since obvious mucus hypersecretion was induced and airway inflammation increased slightly, especially around small airways. Following ozone co-exposure, the increase of IL-4 and IL-13 levels in murine lung caused by OVA sensitization/challenge were reversed. Instead, levels of IL-1β in BALF remained, higher than negative control group. Ozone repeated short exposures also induced significant increase of 8-OHdG in BALF in OVA sensitized and challenged mice.

CONCLUSION

For asthmatic mice undergoing ozone exposures, AHR is not an accurate indicator of the severity of asthma. Repeated short ozone exposures increase mucus hypersecretion, possibly via an increase in oxidative stress and immune dysregulation.

Effect of roflumilast on airway remodelling in a murine model of chronic asthma

BACKGROUND

Airway remodelling is associated with irreversible, or partially reversible, airflow obstruction and ultimately unresponsiveness to asthma therapies such as corticosteroids. Roflumilast is a selective phosphodiesterase-4 inhibitor that has an anti-inflammatory effect in chronic obstructive pulmonary disease (COPD).

OBJECTIVE

The objective of this study was to study the effect of roflumilast on airway inflammation and remodelling in a murine model of chronic asthma.

METHODS

BALB/c mice sensitized to ovalbumin (OVA) were chronically exposed to intranasal OVA administration twice a week for additional 3 months. Roflumilast was administered orally during the intranasal OVA challenge. A lung fibroblast cell line was used in the proliferation assay.

RESULTS

Compared with control mice, mice chronically exposed to OVA developed eosinophilic airway inflammation, airway hyper-responsiveness (AHR), and exhibited features of airway remodelling. Administration of roflumilast significantly inhibited airway inflammation and AHR. Roflumilast also significantly decreased goblet cell hyperplasia and pulmonary fibrosis, which are parameters of airway remodelling. The levels of interleukin (IL)-4, IL-5, and IL-13 in the bronchoalveolar lavage (BAL) fluids were significantly lower in the roflumilast group. In vitro, roflumilast significantly inhibited stem cell factor (SCF)-induced cell proliferation of fibroblasts. The SCF concentration and mRNA expression in a murine model also significantly decreased with roflumilast treatment.

CONCLUSIONS

These results suggest that the administration of roflumilast regulates airway inflammation, AHR, and airway remodelling in a model of chronic asthma. The beneficial effects from roflumilast may be related to the SCF/c-kit pathway.

Increased Expression of p22phox Mediates Airway Hyperresponsiveness in an Experimental Model of Asthma

AIM

Chronic airway diseases such as asthma are associated with increased production of reactive oxygen species (ROS) and oxidative stress. Endogenous NADPH oxidases are a major source of superoxide in lung, but their underlying role in asthma pathology is poorly understood. We sought to characterize the involvement of NADPH oxidase in allergic asthma by studying the role of CYBA (p22phox) in human asthma and murine house dust mite (HDM)-induced allergic airway inflammation.

RESULTS

Increased expression and localization of p22-PHOX were observed in biopsies of asthmatic patients. HDM-treated wild-type mice possessed elevated p22phox expression, corresponding with elevated superoxide production. p22phox knockout (KO) mice did not induce superoxide and were protected against HDM-induced goblet cell hyperplasia and mucus production and HDM-induced airway hyperresponsiveness (AHR). IL-13-induced tracheal hyperreactivity and signal transducer and activator of transcription (STAT)6 phosphorylation were attenuated in the absence of p22phox or catalase pretreatment.

INNOVATION

Our study identifies increased expression of p22phox in lungs of asthmatic patients and in experimental model. The induced AHR and mucus hypersecretion are a result of increased ROS from the p22phox-dependent NADPH oxidase, which in turn activates STAT6 for the pathological feature of asthma.

CONCLUSIONS

Together with the increased p22phox expression in lungs of asthmatic patients, these findings demonstrate a crucial role of p22phox-dependent NADPH oxidase for the development of mucus hypersecretion and AHR in HDM-induced model of asthma. This suggests that inhibition of functional NADPH oxidase by selective interference of p22phox might hold a promising therapeutic strategy for the management of asthma. Antioxid. Redox Signal. 27, 1460-1472.

Illicium verum Extract and Trans-Anethole Attenuate Ovalbumin-Induced Airway Inflammation via Enhancement of Foxp3+ Regulatory T Cells and Inhibition of Th2 Cytokines in Mice

Illicium verum is used in traditional medicine to treat inflammation. The study investigates the effects of IVE and its component, trans-anethole (AET), on airway inflammation in ovalbumin- (OVA-) induced asthmatic mice. Asthma was induced in BALB/c mice by systemic sensitization to OVA, followed by intratracheal, intraperitoneal, and aerosol allergen challenges. IVE and AET were orally administered for four weeks. We investigated the effects of treatment on airway hyperresponsiveness, IgE production, pulmonary eosinophilic infiltration, immune cell phenotypes, Th2 cytokine production in bronchoalveolar lavage, Th1/Th2 cytokine production in splenocytes, forkhead box protein 3 (Foxp3) expression, and lung histology. IVE and AET ameliorated OVA-driven airway hyperresponsiveness (p < 0.01), pulmonary eosinophilic infiltration (p < 0.05), mucus hypersecretion (p < 0.01), and IL-4, IL-5, IL-13, and CCR3 production (p < 0.05), as well as IgE levels (p < 0.01). IVE and AET increased Foxp3 expression in lungs (p < 0.05). IVE and AET reduced IL-4 and increased IFN-γ production in the supernatant of splenocyte cultures (p < 0.05). Histological studies showed that IVE and AET inhibited eosinophilia and lymphocyte infiltration in lungs (p < 0.01). These results indicate that IVE and AET exert antiasthmatic effects through upregulation of Foxp3⁺ regulatory T cells and inhibition of Th2 cytokines, suggesting that IVE may be a potential therapeutic agent for allergic lung inflammation.

Novel Biologicals for the Treatment of Allergic Diseases and Asthma

PURPOSE OF REVIEW

The development of biological therapies has rapidly progressed during the last few years, and major advances were reported for the treatment of allergic diseases, such as atopic dermatitis, allergic rhinitis, urticaria, food allergy, and asthma. Here, we review biologicals targeting the type 2 immune response involving Th2 cells, type 2 innate lymphoid cells, natural killer T cells, mast cells, basophils, and epithelial cells, such as IL-4, IL-5, IL-13, IL-31, tumor necrosis factor alpha (TNF-α), and thymic stromal lymphopoietin (TSLP).

RECENT FINDINGS

The biologicals that have been currently approved for asthma are omalizumab targeting IgE and reslizumab and mepolizumab targeting interleukin (IL)-5. Many other monoclonal antibodies are currently in various phases of clinical development. The new biological therapies for allergic diseases will eventually be tailored to the endotypes of these diseases and the identification of novel biomarkers. Further development of novel biologicals for the treatment of allergic diseases and asthma will be possible upon improved understanding of mechanisms of allergic diseases. Accordingly, further refinement of endotypes of allergen-specific and non-specific type 2 immune response and related inflammatory mediators is needed for optimal treatment of allergic diseases.

Precision medicine in patients with allergic diseases: Airway diseases and atopic dermatitis-PRACTALL document of the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma & Immunology

In this consensus document we summarize the current knowledge on major asthma, rhinitis, and atopic dermatitis endotypes under the auspices of the PRACTALL collaboration platform. PRACTALL is an initiative of the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma & Immunology aiming to harmonize the European and American approaches to best allergy practice and science. Precision medicine is of broad relevance for the management of asthma, rhinitis, and atopic dermatitis in the context of a better selection of treatment responders, risk prediction, and design of disease-modifying strategies. Progress has been made in profiling the type 2 immune response-driven asthma. The endotype driven approach for non-type 2 immune response asthma, rhinitis, and atopic dermatitis is lagging behind. Validation and qualification of biomarkers are needed to facilitate their translation into pathway-specific diagnostic tests. Wide consensus between academia, governmental regulators, and industry for further development and application of precision medicine in management of allergic diseases is of utmost importance. Improved knowledge of disease pathogenesis together with defining validated and qualified biomarkers are key approaches to precision medicine.

Airways antiallergic effect and pharmacokinetics of alkaloids from Alstonia scholaris

BACKGROUND

Alstonia scholaris (L.) R. Br. (Apocynaceae), an important herbal medicine, has been widely used to treat respiratory tract diseases, such as cough, asthma, phlegm, and chronic obstructive pulmonary disease.

PURPOSE

To evaluate pharmacological effect of alkaloids from A. scholaris on ovalbumin induced airways allergic inflammatory model, and explore whether the dosing frequency is related to pharmacokinetics.

STUDY DESIGN

After oral administration of total alkaloids, the pharmacokinetic study of it was investigated. In addition, anti-allergic studies were carried out on ovalbumin-sensitized airways allergic inflammatory model of mice.

METHODS

The pharmacokinetics of total alkaloids (TA) was investigated in SD rat plasma by a fully-validated LC-MS/MS method. Then, an ovalbumin (OVA)-sensitized airways allergic inflammatory model was established, in which mice were intra-gastrically administrated by 3 times a day (8.3 and 16.7mg/kg) based on the pharmacokinetic behavior of TA) and single (25, 50mg/kg) treatment regimen. Dexamethasone was used as a positive control for corticosteroid drugs. Cellular infiltration was assessed in the broncho-alveolar lavage fluid (BALF). Expressions of interleukin-4 (IL-4) and interleukin-10 (IL-10) in the BALF were determined, levels of immunoglobulin E (IgE) and eotaxin in serum were measured, and superoxide dismutase (SOD) activities as well as malondialdehyde (MDA) content in the serum and BALF were examined. Finally, histopathological examination in the lung was assessed by H. E. staining.

RESULTS

The time course of plasma concentration of 4 bioactive indole alkaloids fitted an open two-compartment model after oral administration of total alkaloids at doses of 10, 25, and 50mg/kg. The area under the curve and the maximum concentration values of four major alkaloids increased dose-dependently, and half-life suggested a short-lasting pharmacological effect. Then, an ovalbumin-provoked airways allergic inflammatory model indicated that the pharmacological effect of administration of total alkaloids 3 times a day was a little better than that of single dose daily. The percentage of eosinophils in BALF was reduced obviously and the pathological damage of lung was also attenuated. There was also a significant reduction in IL-4 and promotion in IL-10 in the BALF. Serum IgE and eotaxin expression also significantly decreased in treated animals. Furthermore, the activity of SOD elevated remarkably and lipid peroxidation product (MDA) decreased in the administrated mice.

CONCLUSION

The pharmacological effects administrated for 3 times a day had precedence over single dose daily, which was related to the prolonged retention time and the maintained plasma concentration. Moreover, scholaricine and vallesamine might be responsible for the treatment of allergic asthma, mainly in total alkaloids.

Eotaxin and IL-4 levels are increased in induced sputum and correlate with sputum eosinophils in patients with nonasthmatic eosinophilic bronchitis

Nonasthmatic eosinophilic bronchitis (NAEB) is characterized by chronic cough and airway eosinophilic inflammation. Airway and systemic inflammation cytokine profile have not been comprehensively described in patients with NAEB.The aim of the study was to identify the cytokine profile in sputum and serum of NAEB patients. Furthermore, the relationship between cytokines and clinical features would be evaluated.Induced sputum and serum were collected from untreated NAEB patients and healthy subjects. The cytokine profile in sputum and serum was analyzed by a bead-based multiplex cytokine assay including 21 cytokines.The levels of EGF, eotaxin, GM-CSF, GRO, IFN-γ, IL-1β, IL-4, IL-6, IL-17A, IP-10, MIP-1α, and TNF-α in sputum were significantly higher in NAEB patients than that in healthy subjects (all P < 0.05). Values of area under the receiver operating characteristic curve (AUROC) of these cytokines were all above 0.750. The concentrations of eotaxin and IL-4 were positively correlated with sputum eosinophil percentage (r = 0.726, P = 0.002; r = 0.511, P = 0.043; respectively). No significant correlations between other cytokines (EGF, GM-CSF, GRO, IFN-γ, IL-1β, IL-6, IL-17A, IP-10, MIP-1α, and TNF-α) in sputum and sputum eosinophil percentage were found. The level of IL-4 in serum was slightly higher in NAEB patients than in healthy subjects. However, there was no correlation between serum IL-4 levels and sputum eosinophil percentage.We identified the cytokine profile in sputum and serum from NAEB patients. Sputum eotaxin and IL-4 could have the potential to become the biomarkers for NAEB and might be useful to assist in the diagnosis of NAEB.

Reduced allergic lung inflammation by root extracts from two species of Peucedanum through inhibition of Th2 cell activation

ETHNOPHARMACOLOGICAL EVIDENCE

Peucedani Radix (PR), the root of Peucedanum praeruptorum Dunn (PPD) or Peucedanum decursivum (Miq.) Maxim. (PDM), has long been used in Korea to eliminate sputum, relieve cough, and reduce bronchus contraction. Furthermore, these therapeutic strategies are recognized as general and effective methods in western medicine as well as traditional Korean medicine.

AIM OF THE STUDY

To determine and compare the anti-inflammatory effects of PPD extracts (PPDE) and PDM extracts (PDME) on allergic lung inflammation, using in vivo OVA-induced airway inflammation in mice and in vitro primary cell culture systems.

MATERIALS AND METHODS

Eight-week-old female C57BL/6 mice were placed into four groups (n=4 per group): saline control, OVA-induced allergic lung inflammation with vehicle, or PPDE (200mg/kg) or PDME (200mg/kg) treatment. PR extracts (PRE) were administered from 1 week before 1st OVA sensitization to the day before sacrifice. Mice were sacrificed 18h after last OVA intra-nasal challenge followed by histological and biochemical analyses.

RESULTS

Inflammatory phenotypes were alleviated with oral administration of PRE. PRE treatment decreased mucus production in airway epithelium, inflammatory cell number, eosinophilia, type 2 cytokines, and histamine in bronchoalveolar lavage fluid (BALF). Mice with PRE administration showed diminished activated CD4 T cell (CD4⁺CD25⁺ cell) and GATA-3 level in the lung. In addition, PRE treatment reduced Th2 cell activation in vitro, using Th2 polarization system.

CONCLUSION

Our findings indicate that the anti-inflammatory effects of PRE arise from reduced Th2 cell activation and validate the clinical use of PR in traditional Korean medicine.

Bradykinin B2 receptor expression in the bronchial mucosa of allergic asthmatics: the role of NF-kB

BACKGROUND

Bradykinin (BK) mediates acute allergic asthma and airway remodelling. Nuclear factor-kappa B (NF-kB) is potentially involved in BK B2 receptor (B2R) regulation.

OBJECTIVE

In this observational cross-sectional study, B2R and NF-kB expression was evaluated in bronchial biopsies from mild asthmatics (after diluent/allergen challenge) and healthy controls, examining the role of NF-kB in B2R expression in primary human fibroblasts from normal and asthmatic subjects (HNBFb and HABFb).

METHODS

B2R and NF-kB (total and nuclear) expression was analysed by immunohistochemistry in biopsies from 10 mild intermittent asthmatics (48 h after diluent/allergen challenge) and 10 controls undergoing bronchoscopy. B2R co-localization in 5B5(+) and αSMA(+) mesenchymal cells was studied by immunofluorescence/confocal microscopy, and B2R expression in HABFb/HNBFb incubated with interleukin (IL)-4/IL-13 with/without BK, and after NF-kB inhibitor, by Western blotting.

RESULTS

Bronchial mucosa B2R and nuclear NF-kB expression was higher in asthmatics after diluent (B2R only) and allergen challenge than in controls (P < 0.05), while B2R and NF-kB (total and nuclear) increased after allergen compared with after diluent (P < 0.05). Allergen exposure increased B2R expression in 5B5(+) and αSMA(+) cells. Constitutive B2R protein expression was higher in HABFb than in HNBFb (P < 0.05) and increased in both cell types after IL-13 or IL-4/IL-13 and BK treatment. This increase was suppressed by a NF-kB inhibitor (P < 0.05).

CONCLUSIONS & CLINICAL RELEVANCE

Bronchial B2R expression is constitutively elevated in allergic asthma and is further increased after allergen exposure together with NF-kB expression. NF-kB inhibitor blocked IL-4/IL-13-induced increase in B2R expression in cultured fibroblasts, suggesting a role as potential anti-asthma drug.

Inhibitory effects of l-theanine on airway inflammation in ovalbumin-induced allergic asthma

l-theanine, a water-soluble amino acid isolated from green tea (Camellia sinensis), has anti-inflammatory activity, antioxidative properties, and hepatoprotective effects. However, the anti-allergic effect of l-theanine and its underlying molecular mechanisms have not been elucidated. In this study, we investigated the protective effects of l-theanine on asthmatic responses, particularly airway inflammation and oxidative stress modulation in an ovalbumin (OVA)-induced murine model of asthma. Treatment with l-theanine dramatically attenuated the extensive trafficking of inflammatory cells into bronchoalveolar lavage fluid (BALF). Histological studies revealed that l-theanine significantly inhibited OVA-induced mucus production and inflammatory cell infiltration in the respiratory tract and blood vessels. l-theanine administration also significantly decreased the production of IgE, monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-4, IL-5, IL-13, tumor necrosis factor-alpha (TNF-α), and interferon-gamma in BALF. The lung weight decreased with l-theanine administration. l-theanine also markedly attenuated the OVA-induced generation of reactive oxygen species and the activation of nuclear factor kappa B (NF-κB) and matrix metalloprotease-9 in BALF. Moreover, l-theanine reduced the TNF-α-induced NF-κB activation in A549 cells. Together, these results suggest that l-theanine alleviates airway inflammation in asthma, which likely occurs via the oxidative stress-responsive NF-κB pathway, highlighting its potential as a useful therapeutic agent for asthma management.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

DNA methylation mediates the effect of exposure to prenatal maternal stress on cytokine production in children at age 13½ years: Project Ice Storm

BACKGROUND

Prenatal maternal stress (PNMS) is an important programming factor of postnatal immunity. We tested here the hypothesis that DNA methylation of genes in the NF-κB signaling pathway in T cells mediates the effect of objective PNMS on Th1 and Th2 cytokine production in blood from 13½ year olds who were exposed in utero to the 1998 Quebec ice storm.

RESULTS

Bootstrapping analyses were performed with 47 CpGs across a selection of 20 genes for Th1-type cytokines (IFN-γ and IL-2) and Th2-type cytokines (IL-4 and IL-13). Six CpGs in six different NF-κB signaling genes (PIK3CD, PIK3R2, NFKBIA, TRAF5, TNFRSF1B, and LTBR) remained as significant negative mediators of objective PNMS on IFN-γ secretion after correcting for multiple comparisons. However, no mediation effects on IL-2, IL-4 and IL-13 survived Bonferroni correction.

CONCLUSIONS

The present study provides preliminary evidence supporting the mediating role of DNA methylation in the association between objective aspects of PNMS and child immune states, favoring a Th2 shift.

Antiasthmatic Effects of Eugenol in a Mouse Model of Allergic Asthma by Regulation of Vitamin D3 Upregulated Protein 1/NF-κB Pathway

The aim of the study was to investigate the antiasthmatic effects of eugenol (EUG) and the possible mechanisms. Asthma model was established by ovalbumin induction. A total of 50 mice were randomly assigned to five experimental groups: control, OVA, OVA + dexamethasone (2 mg/kg), OVA + EUG (10 mg/kg), and OVA + EUG (20 mg/kg). Airway resistance (Raw) were measured, histological studies were evaluated by the hematoxylin and eosin (HE) staining, interleukin-4 (IL-4) and interleukin-5 (IL-5) were evaluated by enzyme-linked immunosorbent assay (ELISA), Vitamin D3 upregulated protein 1 (VDUP1), IκBα, P-IκBα, NF-κBP65, and p-NF-κBP65 were measured by Western blotting. Our study demonstrated that EUG inhibited OVA-induced increases in Raw and eosinophil count; IL-4 and IL-5 were recovered. Histological studies demonstrated that EUG substantially inhibited OVA-induced eosinophilia in the lung tissue. Western blotting studies demonstrated that EUG substantially inhibited P-IκBα, NF-κBP65, and p-NF-κBP65 protein levels and increased VDUP1 and IκBα protein levels. These findings suggest that EUG may effectively ameliorate the progression of asthma and could be used as a therapy for patients with allergic asthma.

Nociceptin/orphanin FQ (N/OFQ) modulates immunopathology and airway hyperresponsiveness representing a novel target for the treatment of asthma

BACKGROUND AND PURPOSE

There is evidence supporting a role for the nociceptin/orphanin FQ (N/OFQ; NOP) receptor and its endogenous ligand N/OFQ in the modulation of neurogenic inflammation, airway tone and calibre. We hypothesized that NOP receptor activation has beneficial effects upon asthma immunopathology and airway hyperresponsiveness. Therefore, the expression and function of N/OFQ and the NOP receptor were examined in healthy and asthmatic human airway tissues. The concept was further addressed in an animal model of allergic asthma.

EXPERIMENTAL APPROACH

NOP receptor expression was investigated by quantitative real-time PCR. Sputum N/OFQ was determined by RIA. N/OFQ function was tested using several assays including proliferation, migration, collagen gel contraction and wound healing. The effects of N/OFQ administration in vivo were studied in ovalbumin (OVA)-sensitized and challenged mice.

KEY RESULTS

NOP receptors were expressed on a wide range of human and mouse immune and airway cells. Eosinophils expressed N/OFQ-precursor mRNA and their number correlated with N/OFQ concentration. N/OFQ was found in human sputum and increased in asthma. Additionally, in asthmatic human lungs N/OFQ immunoreactivity was elevated. NOP receptor activation inhibited migration of immunocytes and increased wound healing in airway structural cells. Furthermore, N/OFQ relaxed spasmogen-stimulated gel contraction. Remarkably, these findings were mirrored in OVA-mice where N/OFQ treatment before or during sensitization substantially reduced airway constriction and immunocyte trafficking to the lung, in particular eosinophils. N/OFQ also reduced inflammatory mediators and mucin production.

CONCLUSIONS AND IMPLICATIONS

We demonstrated a novel dual airway immunomodulator/bronchodilator role for N/OFQ and suggest targeting this system as an innovative treatment for asthma.

Erythronium japonicum attenuates histopathological lung abnormalities in a mouse model of ovalbumin-induced asthma

Asthma is a chronic lung condition that can induce mucus hypersecretion and pulmonary obstruction and may even cause death, particularly in children and older individuals. Erythronium japonicum (E. japonicum) is a traditional herb used in Korea and East Asian countries that has been found to exert free radical scavenging activity and anti-proliferative effects in human colorectal carcinoma cells. In the present study, we evaluated the anti-asthmatic effects of an extract of E. japonicum in a mouse model of ovalbumin (OVA)-induced asthma. Female BALB/c mice were sensitized with an intraperitoneal injection of OVA and aluminum hydroxide hydrate on days 1 and 8 and then received the following treatments on days 21 to 25: i) control (no treatment), ii) sterilized tap water (given orally), iii) 1 mg/kg/day dexamethasone (administered orally), iv) 60 mg/kg/day E. japonicum extract, and v) 600 mg/kg/day E. japonicum extract. On the same days, all the mice except those in the control group were challenged 1 h later with nebulized 5% OVA for 30 min. We found that treatment with E. japonicum extract suppressed the OVA-induced increase in the number of white blood cells and decreased the IgE level in the bronchoalveolar lavage fluid samples obtained from the mice. Histopathological analysis of the lung tissues revealed that E. japonicum attenuated the asthma-related morphological changes in the mouse lung tissue, including the increased secretion of mucus in the bronchioles, eosinophil infiltration around the bronchioles and vessels, and goblet cell and epithelial cell hyperplasia. Immunohistochemical analysis revealed that treatment with E. japonicum extract suppressed the OVA-induced proliferation of T helper cells (CD4⁺) and B cells (CD19⁺) in the mouse lung tissue. Furthermore, treatment with E. japonicum extract modulated the expression of both T helper 2 cell-related factors [GATA binding protein 3 (GATA-3), tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-5, IL-6 and IL-13], as well as that of T helper 1 cell-related factors [(interferon-γ (IFN-γ), IL-12p35 and IL-12p40]. These findings suggest that E. japonicum may potentially be used as an anti-asthmatic treatment.

Platycodin D Attenuates Airway Inflammation in a Mouse Model of Allergic Asthma by Regulation NF-κB Pathway

In this work, the anti-asthma potential of platycodin D (PLD) was studied by investigation of its effect to suppress airway inflammation, a murine model of asthma and the possible mechanisms. A total of 50 mice were randomly assigned to five experimental groups: control, ovalbumin (OVA), OVA+dexamethasone (2 mg/kg) and OVA+PLD (40, 80 mg/kg). Airway resistance (Raw) were measured; airway histological studies were evaluated by the hematoxylin and eosin (HE) staining; interleukin-4 (IL-4), interleukin-5(IL-5), and interleukin-13 in bronchoalveolar lavage fluid (BALF) were evaluated by enzyme-linked immunosorbent assay (ELISA); NF-κBp65, p-NF-κBp65, p-IKKα, IKKα, p-IKKβ, p-IкBα, and IкBα of airway were measured by Western blotting. Our study demonstrated that PLD inhibited OVA-induced increases in Raw and eosinophil count in airway; IL-4, IL-5, and IL-13 were recovered in BALF. Histological studies demonstrated that PLD substantially inhibited OVA-induced eosinophilia in airway tissue. Western blotting studies demonstrated that PLD substantially inhibited NF-κB pathway. These findings suggest that PLD may effectively ameliorate the progression of asthma and could be used as a therapy for patients with allergic asthma.

Anti-asthmatic effects of oxymatrine in a mouse model of allergic asthma through regulating CD40 signaling

The aim of the study was to investigate the anti-asthmatic effects of oxymatrine (OXY) and the possible underlying mechanisms. The mouse asthma model was established by ovalbumin (OVA) intraperitoneal injection. A total of fifty mice were randomly assigned to five groups: control, OVA, OVA + dexamethasone (Dex, 2 mg · kg(-1)), and OVA + OXY (40 mg · kg(-1)), and OVA + OXY (80 mg · kg(-1)), respectively. Histological studies were conducted by the hematoxylin and eosin (HE) staining, the levels of interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-13, and IgE were evaluated by enzyme-linked immunosorbent assay (ELISA), and the protein level of CD40 was analyzed by Western blotting. OXY inhibited OVA-induced increases in eosinophil count; the levels of IL-4, IL-5, IgE, and IL-13 were recovered. It also substantially inhibited OVA-induced eosinophilia in lung tissues and the expression of CD40 protein. These findings suggest that OXY may effectively ameliorate the progression of asthma and could be explored as a possible therapy for patients with allergic asthma.

Will nonasthmatic eosinophilic bronchitis develop into chronic airway obstruction?: a prospective, observational study

OBJECTIVE

The long-term prognosis of nonasthmatic eosinophilic bronchitis (NAEB) is still unclear. The aim of this study was to observe the frequency of relapse among patients with NAEB and the likelihood of NAEB developing into chronic airflow obstruction over time.

METHODS

Patients with NAEB were followed for at least 1 year between 2003 and 2013. During this period, we evaluated clinical symptoms, sputum eosinophil count, spirometry, and bronchial hyperresponsiveness. A linear mixed model was adopted to determine the relationship between time and lung function.

RESULTS

A total of 234 patients with NAEB were identified, of whom 141 were followed for > 1 year (median, 4.1 years). Up to 59.6% of patients had a relapse after treatment. Both allergic rhinitis (OR, 4.37; 95% CI, 1.049-18.203; P = .043) and sputum eosinophilia after 4 weeks of treatment with inhaled corticosteroids (OR, 9.493; 95% CI, 2.381-37.850; P = .001) were risk factors for relapse. Among the 141 patients, mild asthma developed in eight (5.7%). During the follow-up period, no progressive decline in FVC, FEV1, and FEV1/FVC were observed (P > .05). Although the proportion of small airway dysfunction (maximum midexpiratory flow [MMEF] < 65%) significantly increased at the last visit in all groups (all P < .05), only the relapse group showed an MMEF decline at the end of follow-up (P < .05) in the linear mixed model.

CONCLUSIONS

More than 50% of patients with NAEB have repeated episodes associated with persistent sputum eosinophilia after treatment and allergic rhinitis. In the current cohort, chronic airway obstruction does not develop despite small airway dysfunction increases over time.

Caerulomycin A inhibits Th2 cell activity: a possible role in the management of asthma

We have recently demonstrated that Caerulomycin A induces regulatory T cells differentiation by suppressing Th1 cells activity. The role of regulatory T cells is well established in suppressing the function of Th2 cells. Th2 cells are known to inflict the induction of the activation of asthma. Consequently, in the present study, we monitored the influence of Caerulomycin A in inhibiting the activity of Th2 cells and its impact in recuperating asthma symptoms. Interestingly, we observed that Caerulomycin A significantly suppressed the differentiation of Th2 cells, as evidenced by downregulation in the GATA-3 expression. Further, decline in the levels of IL-4, IL-5 and IL-13 cytokines and IgE was noted in the animals suffering from asthma. Furthermore, we noticed substantial suppression in the inflammatory response and number of eosinophils in the lungs. In essence, this study signifies an important therapeutic role of Caerulomycin A in asthma.

Increased production of IL-17 in children with autism spectrum disorders and co-morbid asthma

Inflammation and asthma have both been reported in some children with autism spectrum disorder (ASD). To further assess this connection, peripheral immune cells isolated from young children with ASD and typically developing (TD) controls and the production of cytokines IL-17, -13, and -4 assessed following ex vivo mitogen stimulation. Notably, IL-17 production was significantly higher following stimulation in ASD children compared to controls. Moreover, IL-17 was increased in ASD children with co-morbid asthma compared to controls with the same condition. In conclusion, children with ASD exhibited a differential response to T cell stimulation with elevated IL-17 production compared to controls.

Mast cells in airway diseases and interstitial lung disease

Mast cells are major effector cells of inflammation and there is strong evidence that mast cells play a significant role in asthma pathophysiology. There is also a growing body of evidence that mast cells contribute to other inflammatory and fibrotic lung diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. This review discusses the role that mast cells play in airway diseases and highlights how mast cell microlocalisation within specific lung compartments and their cellular interactions are likely to be critical for their effector function in disease.

Inhibition of allergic airway inflammation through the blockage of NF-κB activation by ellagic acid in an ovalbumin-induced mouse asthma model

Allergic asthma is a complex inflammatory disease characterized by airway hyperresponsiveness, eosinophilic inflammation and the hypersecretion of mucus by goblet cells. Ellagic acid (EA), a natural polyphenolic compound present as ellagitannins in fruits and fruit juices, has been reported to show potent anti-inflammatory properties in various diseases. We aimed to investigate the effects of EA in an ovalbumin (OVA)-induced mouse asthma model and to explore its potential mechanism of action. Our results showed that EA resulted in a significant reduction in lung eosinophilia, increased Th2 cytokines in bronchoalveolar lavage fluid and increased OVA-induced specific IgE in serum samples. Moreover, histological examination showed that EA markedly inhibited lung eosinophilic inflammation and goblet cell hyperplasia. In addition, EA attenuated the development of airway hyperresponsiveness and blocked NF-κB activation. These results demonstrate that EA shows obvious anti-inflammatory effects in OVA-induced asthma in a mouse model, possibly through inhibiting NF-κB activation. Therefore it may be a potential therapeutic agent for the treatment of allergic asthma.

Anti-asthma effects of synthetic salidroside through regulation of Th1/Th2 balance

AIM

The aim of the study was to investigate the effect and mechanism of action of synthetic salidroside in an ovalbumin (OVA)-induced asthma model in mice.

METHOD

BALB/c mice were sensitized with an intraperitoneal injection of ovalbumin (OVA) to induce a mouse model of asthma in paracmasis. The mice were treated with dexamethasone as the positive control. At the end of the study, respiratory reactivity was detected, the numbers of various kinds of white blood cells in the bronchoalveolar lavage fluid (BALF) were counted, and the levels of IL-4 and INF-γ in BALF were determined. Quantitative PCR was used to detect the mRNA contents of IL-4 and INF-γ in lung tissue. Histologic examination was performed to observe inflammatory cellular infiltration.

RESULTS

Salidroside treatment virtually eliminated airway hyper-reactivity, markedly reduced the eosinophil percent, obviously reduced the levels of IL-4 and raised INF-γ in the bronchoalveolar lavage fluid (BALF) compared with the sham-treated group. Quantitative PCR on the mRNA content of IL-4 and INF-γ provided confirmation. Lung histologic observations showed that salidroside reduced inflammation and edema. These effects were equivalent to the effects of dexamethasone.

CONCLUSION

Synthetic salidroside exhibits an anti-asthma effect which is related to the regulation of Th1/Th2 balance. This provides a new possibility for treatment of allergic asthma.

Bacillus subtilis KCTC 11782BP-produced alginate oligosaccharide effectively suppresses asthma via T-helper cell type 2-related cytokines

According to the World Health Organization in 2013, 235 million people are afflicted with asthma. Asthma is a severe pulmonary disease that can be caused by the imbalance of T-helper (Th) type 1 (Th1) and type 2 (Th2) cells, and it is potentially fatal. In this study, we evaluated the anti-asthmatic effect of alginate oligosaccharide (AO), which was prepared from seaweed and converted by Bacillus subtilis KCTC 11782BP, in the mouse model of ovalbumin (OVA)-induced asthma. BALB/c mice were divided into the vehicle control (sensitized but not challenged), asthma induction, positive control (1 mg/kg dexamethasone), 50 mg/kg/day AO-treated, 200 mg/kg/day AO-treated, and 400 mg/kg/day AO-treated groups. The numbers or levels of inflammatory cells, eosinophils, and immunoglobulin (Ig) E were measured in bronchoalveolar lavage fluid (BALF), and asthma-related morphological and cytokine changes were analyzed in lung tissues. Our results show that AO dramatically reduced inflammatory cell numbers, eosinophil count, and IgE levels in BALF, and it dose-dependently inhibited asthmatic histopathological changes in the lung. In addition, AO dose-dependently suppressed the expression of CD3+ T-cell co-receptors, CD4+ Th cells, CD8+ cytotoxic T-cell-related factors, macrophages, and MHCII class. AO dose-dependently decreased the expression levels of Th1/2 cells-regulatory transcription factors such as GATA-3 which modulates Th2 cell proliferation and T-bet which does Th1 cell proliferation. The mRNA levels of all Th1/2-related cytokines, except IL-12α, were dose-dependently suppressed by AO treatment. In particular, the mRNA levels of IL-5, IL-6, and IL-13 were significantly inhibited by AO treatment. Our findings suggest that AO has the potential to be an anti-asthmatic drug candidate, due to its modulation of Th1/Th2 cytokines, which contribute to the pathogenesis of asthma.

Pathobiology of severe asthma

Severe asthma (SA) afflicts a heterogeneous group of asthma patients who exhibit poor responses to traditional asthma medications. SA patients likely represent 5-10% of all asthma patients; however, they have a higher economic burden when compared with milder asthmatics. Considerable research has been performed on pathological pathways and structural changes associated with SA. Although limitations of the pathological approaches, ranging from sampling, to quantitative assessments, to heterogeneity of disease, have prevented a more definitive understanding of the underlying pathobiology, studies linking pathology to molecular markers to targeted therapies are beginning to solidify the identification of select molecular phenotypes. This review addresses the pathobiology of SA and discusses the current limitations of studies, the inflammatory cells and pathways linked to emerging phenotypes, and the structural and remodeling changes associated with severe disease. In all cases, an effort is made to link pathological findings to specific clinical/molecular phenotypes.

Approach to chronic cough: the neuropathic basis for cough hypersensitivity syndrome

Chronic cough is a common symptom that can be difficult to manage because associated causes may remain elusive and treatment of any associated cause may not provide relief. Current antitussives have limited efficacy and undesirable side-effects. Patients with chronic cough describe sensory symptoms suggestive of upper airway and laryngeal neural dysfunction, and report cough triggered by low-level physical and chemical stimuli supporting the concept of cough reflex hypersensitivity. Mechanisms underlying peripheral and central augmentation of the afferent cough pathways have been identified. Chronic cough is a neuropathic condition that could be secondary to sensory nerve damage caused by inflammatory, infective and allergic factors. Recent success in the treatment of chronic cough with agents used for treating neuropathic pain such as gabapentin and amitryptiline would also support this concept. Research into neuropathic cough may lead to the discovery of more effective antitussives.

Increased frequency of dual-positive TH2/TH17 cells in bronchoalveolar lavage fluid characterizes a population of patients with severe asthma

BACKGROUND

TH2 cells can further differentiate into dual-positive TH2/TH17 cells. The presence of dual-positive TH2/TH17 cells in the airways and their effect on asthma severity are unknown.

OBJECTIVE

We sought to study dual-positive TH2/TH17 cells in bronchoalveolar lavage (BAL) fluid from asthmatic patients, examine their response to glucocorticoids, and define their relevance for disease severity.

METHODS

Bronchoscopy and lavage were performed in 52 asthmatic patients and 25 disease control subjects. TH2 and TH2/TH17 cells were analyzed by using multicolor flow cytometry and confocal immunofluorescence microscopy. Cytokines were assayed by means of ELISA.

RESULTS

Dual-positive TH2/TH17 cells were present at a higher frequency in BAL fluid from asthmatic patients compared with numbers seen in disease control subjects. High-level IL-4 production was typically accompanied by high-level IL-17 production and coexpression of GATA3 and retinoic acid receptor-related orphan receptor γt. Increased presence of TH2/TH17 cells was associated with increased IL-17 production in lavage fluid. TH2/TH17 cell counts and IL-17 production correlated with PC20 for methacholine, eosinophil counts, and FEV1. TH2/TH17 cells, unlike TH2 cells, were resistant to dexamethasone-induced cell death. They expressed higher levels of mitogen-activated protein-extracellular signal-regulated kinase kinase 1, a molecule that induces glucocorticoid resistance. On the basis of the dominance of BAL fluid TH2 or TH2/TH17 cells, we identified 3 subgroups of asthma: TH2(predominant), TH2/TH17(predominant), and TH2/TH17(low). The TH2/TH17(predominant) subgroup manifested the most severe form of asthma, whereas the TH2/TH17(low) subgroup had the mildest asthma.

CONCLUSION

Asthma is associated with a higher frequency of dual-positive TH2/TH17 cells in BAL fluid. The TH2/TH17(predominant) subgroup of asthmatic patients manifested glucocorticoid resistance in vitro. They also had the greatest airway obstruction and hyperreactivity compared with the TH2(predominant) and TH2/TH17(low) subgroups.