Balance between proinflammatory cytokines and their inhibitors in bronchial lavage from patients with status asthmaticus

Clinical features of omicron SARS-CoV-2 variants infection associated with co-infection and ICU-acquired infection in ICU patients

Background

Although the decreasing rate of hospital admission in the omicron wave has led countries to loosen control, still the patients requires ICU admission. It is common for viral respiratory infections to be co-infected with bacteria. However, the difference between co-infection and ICU-acquired infection on their clinical characteristics and outcomes during the Omicron wave was little reported.

Methods

Clinical and microbiological data were collected from ICU patients with omicron infection between April 1st, 2022, and May 31th, 2022 and a comprehensive comparative study of the clinical characteristics and endpoint were conducted.

Results

The Omicron SARS-CoV-2 variants-infected patients requiring intensive care had high rates of co-infection (42.55%). Additionally, the ICU COVID-19 patients with co-infection showed more severe clinical features compared to those with ICU-acquired infection. Furthermore, Multivariate Cox analysis demonstrated that co-infection (hazard ratio: 4.670, p = 0.018) was a significant risk factor for poor outcomes in ICU patients with COVID-19. Besides, Kaplan-Meier survival curve analysis revealed that COVID-19 patients with co-infection had a significantly shorter 28-Day survival time compared to those with ICU-acquired infection (p < 0.001). Finally, our investigation identified a significant association between the presence of Candida app. in the broncho-alveolar lavage and an elevated risk of mortality (OR: 13.80, p = 0.002) and invasive ventilation (OR: 5.63, p = 0.01).

Conclusion

Co-infection is prevalent among patients requiring intensive care and is linked to unfavorable outcomes in the Omicron wave. Consequently, more attention may be needed for the empirical antibacterial treatment in ICU patients within the COVID-19 Omicron variant, especially anti-fungi.

Ivy Leaf Dry Extract EA 575® Has an Inhibitory Effect on the Signalling Cascade of Adenosine Receptor A2B

Ivy leaf dry extract EA 575® is used to improve complaints of chronic inflammatory bronchial diseases and acute inflammation of the respiratory tract accompanied by coughing. Its mechanism of action has so far been explained by influencing β2-adrenergic signal transduction. In the present study, we investigated a possible influence on adenosine receptor A2B (A2BAR) signalling, as it has been described to play a significant and detrimental role in chronic inflammatory airway diseases. The influence of EA 575® on A2BAR signalling was assessed with measurements of dynamic mass redistribution. Subsequently, the effects on A2BAR-mediated second messenger cAMP levels, β-arrestin 2 recruitment, and cAMP response element (CRE) activation were examined using luciferase-based HEK293 reporter cell lines. Lastly, the impact on A2BAR-mediated IL-6 release in Calu-3 epithelial lung cells was investigated via the Lumit™ Immunoassay. Additionally, the adenosine receptor subtype mediating these effects was specified, and A2BAR was found to be responsible. The present study demonstrates an inhibitory influence of EA 575® on A2BAR-mediated general cellular response, cAMP levels, β-arrestin 2 recruitment, CRE activation, and IL-6 release. Since these EA 575®-mediated effects occur within a time frame of several hours of incubation, its mode of action can be described as indirect. The present data are the first to describe an inhibitory effect of EA 575® on A2BAR signalling. This may offer an explanation for the beneficial clinical effects of the extract in adjuvant asthma therapy.

Norisoboldine exerts antiallergic effects on IgE/ovalbumin-induced allergic asthma and attenuates FcεRI-mediated mast cell activation

Allergic asthma is an inflammatory lung disorder, and mast cells play crucial roles in the development of this allergic disease. Norisoboldine (NOR), the major isoquinoline alkaloid present in Radix Linderae, has received considerable attention because it has anti-inflammatory effects. Herein, the aim of this study was to explore the antiallergic effects of NOR on allergic asthma in mice and mast cell activation. In a murine model of ovalbumin (OVA)-induced allergic asthma, oral administration at 5 mg/kg body weight (BW) of NOR produced strong reductions in serum OVA-specific immunoglobulin E (IgE) levels, airway hyperresponsiveness, and bronchoalveolar lavage fluid (BALF) eosinophilia, while an increase in CD4+Foxp3+ T cells of the spleen was detected. Histological studies demonstrated that NOR treatment significantly ameliorated the progression of airway inflammation including the recruitment of inflammatory cells and mucus production by decreasing levels of histamine, prostaglandin D2 (PGD2), interleukin (IL)-4, IL-5, IL-6, and IL-13 in BALF. Furthermore, our results revealed that NOR (3 ∼ 30 μM) dose-dependently reduced expression of the high-affinity receptor for IgE (FcεRI) and the production of PGD2 and inflammatory cytokines (IL-4, IL-6, IL-13, and TNF-α), and also decreased degranulation of bone marrow-derived mast cells (BMMCs) activated by IgE/OVA. In addition, a similar suppressive effect on BMMC activation was observed by inhibition of the FcεRI-mediated c-Jun N-terminal kinase (JNK) signaling pathway using SP600125, a selective JNK inhibitor. Collectively, these results suggest that NOR may have therapeutic potential for allergic asthma at least in part through regulating the degranulation and the release of mediators by mast cells.

Specific IgE against the house dust mite allergens Der p 5, 20 and 21 influences the phenotype and severity of atopic diseases

BACKGROUND

House dust mites (HDM) are among the most important sources for airborne allergens with high relevance for atopic diseases. Routine tests contain only 4 of 32 registered allergens of Dermatophagoides pteronyssinus. Clinical relevance and pathomechanistic properties of many allergens are not well understood.

OBJECTIVE

The association of several HDM allergens with allergic rhinitis, allergic asthma, and atopic dermatitis was investigated to identify allergens with biomarker potential and to transfer them into diagnostics.

METHODS

Eight out of nine D. pteronyssinus allergens (nDer p 1, rDer p 2, rDer p 5, rDer p 7, rDer p 10, rDer p 13, rDer p 20, rDer p 21, rDer p 23) were recombinantly expressed and purified. Sensitization patterns of 384 HDM-allergic individuals exhibiting different clinical phenotypes were analyzed with a serum-saving multiplex array.

RESULTS

Sensitization to more than three mite allergens (sensitization count) was associated with allergic asthma and/or atopic dermatitis. Reactions to Der p 5 and Der p 21 were more frequent in allergic asthma compared to allergic rhinitis. Atopic dermatitis patients were more often sensitized to Der p 5, Der p 20, and Der p 21 among others. Der p 20-IgE > 80 kU/L was associated with severe atopic dermatitis in 75% of patients.

CONCLUSION

This study demonstrates the clinical importance of the sensitization count and of certain allergens (Der p 5, Der p 20, and Der p 21) not available for routine diagnostics yet. Implementing them as well as the sensitization count in diagnostic measures will improve diagnosis and risk assessment of HDM-allergic patients.

A spatially resolved atlas of the human lung characterizes a gland-associated immune niche

Single-cell transcriptomics has allowed unprecedented resolution of cell types/states in the human lung, but their spatial context is less well defined. To (re)define tissue architecture of lung and airways, we profiled five proximal-to-distal locations of healthy human lungs in depth using multi-omic single cell/nuclei and spatial transcriptomics (queryable at lungcellatlas.org ). Using computational data integration and analysis, we extend beyond the suspension cell paradigm and discover macro and micro-anatomical tissue compartments including previously unannotated cell types in the epithelial, vascular, stromal and nerve bundle micro-environments. We identify and implicate peribronchial fibroblasts in lung disease. Importantly, we discover and validate a survival niche for IgA plasma cells in the airway submucosal glands (SMG). We show that gland epithelial cells recruit B cells and IgA plasma cells, and promote longevity and antibody secretion locally through expression of CCL28, APRIL and IL-6. This new 'gland-associated immune niche' has implications for respiratory health.

Association of Interleukin 6 and Interleukin 8 genes polymorphisms with house dust mite-induced nasal-bronchial allergy in a sample of Indian patients

Background

Genetic background of nasal-bronchial allergy (NBA) is well documented. House Dust Mites (HDMs) are reported to elicit NBA symptoms. Susceptibility to HDM sensitization varies considerably from person to person. Interleukin 6 (IL 6) and Interleukin 8 (IL 8) are studied previously for genetic association with several diseases. To the best of our knowledge, the genetic association of HDM-induced NBA has not been largely reported from India. The aim of our present study was to evaluate any possible association of IL 6 and IL 8 gene polymorphisms with HDM-induced NBA in an Indian population.

Methods

IL 6 (− 572G/C, − 597G/A) and IL 8 polymorphisms (− 251A/T, + 781C/T) were analyzed in a HDM-sensitized group (N = 372) and a control group (N = 110). Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR–RFLP) based genotyping was done. Chi-square test and Fisher’s exact tests were applied for statistical analysis.

Results

IL 6 − 597G/A and IL 8 + 781C/T were not associated with HDM-sensitization, while IL 6 − 72G/C and IL 8 − 51A/T showed significant associations in terms of both genotype and allele frequencies. For both the SNPs, minor allele frequencies were significantly higher in the patients compared to the control. Moreover, IL 6 -572G/C and IL 8 -251A/T were found to be strongly linked with HDM sensitization and severity.

Conclusion

This is probably the pioneer study to describe the association of IL 6 and IL 8 polymorphisms with HDM sensitization in any Indian population. The results suggested that IL 6 -572G/C and IL 8 -251A/T may exert a risk of HDM sensitization leading to NBA.

In utero exposures to mint-flavored JUUL aerosol impair lung development and aggravate house dust mite-induced asthma in adult offspring mice

There are few reports concerning electronic nicotine delivery system (ENDS) use during pregnancy and no studies on asthma in prenatally JUUL-exposed offspring. Here, we tested the hypothesis that in utero JUUL exposure causes unfavorable birth outcomes and lasting pulmonary health effects in adult offspring. BALB/c dams were exposed to either air or mint-flavored JUUL aerosol, 1-hr/d, 20 consecutive days during gestation. Offspring were sacrificed on post-natal day (PND) 0 or at 11-week of age, following house dust mite (HDM) challenge. Gene expression was assessed in the uterine/placental tissue of the dams and lung responses were assessed in offspring at PND0 and at 11 weeks of age. JUUL-exposed offspring exhibited decreased body weights and lengths at PND0. These birth outcomes were accompanied by dysregulation of 54 genes associated with hypoxia and oxidative stress in the uterine/placental tissues of JUUL-exposed dams, as well as 24 genes in the lungs of the offspring related to Wnt signaling, plus 9 genes related to epigenetics, and 7 genes related to inflammation. At 11 weeks of age, JUUL + HDM exposed mice exhibited pulmonary inflammation when compared to their respective air + HDM controls. Additionally, the JUUL + HDM exposure dysregulated several genes associated with allergies and asthma. Further, the JUUL + HDM females showed decreased methylation of the promoter region of the Il10ra gene. Taken together, our mouse model shows that inhalation of JUUL aerosols during pregnancy affects the intrauterine environment, impairs lung development, and heightens the effects of allergic airway responses later in life.

Investigational approaches for unmet need in severe asthma

INTRODUCTION

Molecular antibodies (mAb) targeting inflammatory mediators are effective in T2-high asthma. The recent approval of Tezepelumab presents a novel mAb therapeutic option to those with T2-low asthma.

AREAS COVERED

We discuss a number of clinical problems pertinent to severe asthma which are less responsive to current therapies, such as persistent airflow obstruction and airway hyperresponsiveness. We discuss selected investigational approaches, including a number of candidate therapies under investigation in two adaptive platform trials currently in progress, with particular reference to this unmet need, as well as their potential in phenotypes such as neutrophilic asthma and obese asthma, which may or may not overlap with a T2-high phenotype.

EXPERT OPINION

The application of discrete targeting approaches to T2-low molecular phenotypes, including those phenotypes in which inflammation may not arise within the airway, has yielded variable results to date. Endotypes associated with T2-low asthma are likely to be diverse but await validation. Investigational therapeutic approaches must, likewise, be diverse if the goal of remission is to become attainable for all those living with asthma.

STAT3 inhibition decreases ATP-induced MUC8 gene expression in human airway epithelial cells

Background: Contact between the human pulmonary system and bacteria, viruses, or other pathogens can induce airway diseases. Although pathogen-induced mucus oversecretion and hyperproduction are frequently observed in the human respiratory tract, the molecular mechanisms of pathogen-induced mucus hypersecretion and overproduction remain unclear. The objective of this study was to investigate the physiological signaling mechanism of ATP-induced MUC8 gene expression in human airway epithelial cells. Methods: Real-time reverse transcription polymerase chain reaction, a cytokine array, and a Ca2+ concentration assay were performed to investigate the ATP/P2Y2-induced MUC8 gene expression levels in human airway epithelial cells. Results: The ATP/P2Y2 complex robustly secreted interleukin (IL)-6 in a time-dependent manner, whereas siRNA-P2Y2 did not. Moreover, ATP/P2Y2 induced MUC8 gene expression. IL-6 secreted by ATP strongly elevated ATP/P2Y2-induced MUC8 gene expression compared to ATP/P2Y2. Interestingly, a specific STAT3 inhibitor, 5,15-DPP, dramatically inhibited ATP/P2Y2/IL-6-induced STAT3 phosphorylation and resulted in an approximately 5-fold decrease in MUC8 gene expression. Conclusions: We showed that IL-6-activated STAT6 is essential for ATP/P2Y2-induced MUC8 gene expression as part of inflammatory signaling by cytokines during airway inflammation. Our results provide a new molecular understanding of the signaling mechanism of MUC8 gene expression during airway inflammation.

The Potential Use of Saliva as a Biofluid for Systemic Inflammatory Response Monitoring in Children with Pneumonia

OBJECTIVE

To investigate the levels of C-reactive protein, procalcitonin, calprotectin, interleukin 1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) in both saliva and serum in children with community-acquired pneumonia and to compare the saliva response with the systemic response.

METHODS

Forty hospitalized children with community-acquired pneumonia aged between 1 mo and 15 y; and 40 healthy controls were included. Both serum and saliva samples were collected on admission and at the time of discharge.

RESULTS

Calculated differences between values for each serum and salivary parameter on admission and before discharge named delta (Δ) values were used for correlation analysis. Salivary Δ values of each parameter were moderately/strongly correlated with their corresponding serum Δ levels [IL-1β ÷ (r = 0.554, p < 0.001); IL-6 ÷ (r = 0.484, p = 0.002); PCT ÷ (r = 0.737, p < 0.001); TNF-α ÷ (r = 0.587, p < 0.001); CRP ÷ (r = 0.703, p < 0.001); and calprotectin ÷ (r = 0.774, p < 0.001)].

CONCLUSIONS

This study will evaluate the reflection of systemic changes in saliva and the efficacy of saliva in pediatric patients with pneumonia. Results will highlight saliva potential use as a biofluid for systemic monitoring in this patient group.

Oral cavity response to air pollutant exposure and association with pulmonary inflammation and symptoms in asthmatic children

Exposure to fine particulate matter (PM_2.5) and ozone (O₃) may lead to inflammation and oxidative damage in the oral cavity, which is hypothesized to contribute to the worsening of airway inflammation and asthma symptoms. In this panel study of 43 asthmatic children aged 5-13 years old, each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, saliva samples were collected and subsequently analyzed for interleukin 6 (IL-6) and eosinophil cationic protein (ECP) as biomarkers of inflammation and malondialdehyde (MDA) as a biomarker of oxidative stress in the oral cavity. At each visit, children were measured for fractional exhaled nitric oxide (FeNO) as a marker of pulmonary inflammation. Asthma symptoms of these children were measured using the Childhood Asthma Control Test (C-ACT). We found that an interquartile range (IQR) increase in 24-h average personal exposure to PM_2.5 measured 1 and 2 days prior was associated with increased salivary IL-6 concentration by 3.0% (95%CI: 0.2%-6.0%) and 4.2% (0.7%-8.0%), respectively. However, we did not find a clear association between personal O₃ exposure and any of the salivary biomarkers, except for a negative association between salivary MDA and O₃ exposure measured 1 day prior. An IQR increase in salivary IL-6 concentration was associated with significantly increased FeNO by 28.8% (4.3%-53.4%). In addition, we found that increasing salivary IL-6 concentrations were associated with decreased individual and total C-ACT scores, indicating the worsening of asthma symptoms. We estimated that 13.2%-22.2% of the associations of PM_2.5 exposure measured 1 day prior with FeNO and C-ACT scores were mediated by salivary IL-6. These findings suggest that the induction of inflammation in the oral cavity may have played a role in linking air pollution exposure with the worsening of airway inflammation and asthma symptoms.

IL-37 regulates allergic inflammation by counterbalancing pro-inflammatory IL-1 and IL-33

BACKGROUND

Children with asthma have impaired production of interleukin (IL) 37; in mice, IL-37 reduces hallmarks of experimental allergic asthma (EAA). However, it remains unclear how IL-37 exerts its inhibitory properties in asthma. This study aimed to identify the mechanism(s) by which IL-37 controls allergic inflammation.

METHODS

IL-37 target cells were identified by single-cell RNA-seq of IL-1R5 and IL-1R8. Airway tissues were isolated by laser-capture microdissection and examined by microarray-based gene expression analysis. Mononuclear cells (MNC) and airway epithelial cells (AECs) were isolated and stimulated with allergen, IL-1β, or IL-33 together with recombinant human (rh) IL-37. Wild-type, IL-1R1- and IL-33-deficient mice with EAA were treated with rhIL-37. IL-1β, IL-33, and IL-37 levels were determined in sputum and nasal secretions from adult asthma patients without glucocorticoid therapy.

RESULTS

IL-37 target cells included AECs, T cells, and dendritic cells. In mice with EAA, rhIL-37 led to differential expression of >90 genes induced by IL-1β and IL-33. rhIL-37 reduced production of Th2 cytokines in allergen-activated MNCs from wild-type but not from IL-1R1-deficient mice and inhibited IL-33-induced Th2 cytokine release. Furthermore, rhIL-37 attenuated IL-1β- and IL-33-induced pro-inflammatory mediator expression in murine AEC cultures. In contrast to wild-type mice, hIL-37 had no effect on EAA in IL-1R1- or IL-33-deficient mice. We also observed that expression/production ratios of both IL-1β and IL-33 to IL-37 were dramatically increased in asthma patients compared to healthy controls.

CONCLUSION

IL-37 downregulates allergic airway inflammation by counterbalancing the disease-amplifying effects of IL-1β and IL-33.

Metal-Stimulated Interleukin-6 Production Through a Proton-Sensing Receptor, Ovarian Cancer G Protein-Coupled Receptor 1, in Human Bronchial Smooth Muscle Cells: A Response Inhibited by Dexamethasone

Purpose

Human bronchial smooth muscle cells (BSMCs) contribute to airway obstruction and hyperresponsiveness in patients with bronchial asthma. BSMCs also generate cytokines and matricellular proteins in response to extracellular acidification through the ovarian cancer G protein-coupled receptor 1 (OGR1). Cobalt (Co) and nickel (Ni) are occupational agents, which cause occupational asthma. We examined the effects of Co and Ni on interleukin-6 (IL-6) secretion by human BSMCs because these metals may act as ligands of OGR1.

Methods

Human BSMCs were incubated in Dulbecco's Modified Eagle Medium (DMEM) containing 0.1% bovine serum albumin (BSA) (0.1% BSA-DMEM) for 16 hours and stimulated for the indicated time by exchanging the medium with 0.1% BSA-DMEM containing any of the metals or pH-adjusted 0.1% BSA-DMEM. IL-6 mRNA expression was quantified via reverse transcription polymerase chain reaction (RT-PCR) using the real-time TaqMan technology. IL-6 was measured using an enzyme-linked immunosorbent assay. Dexamethasone (DEX) was added 30 minutes before each stimulation. To knock down the expression of OGR1 in BSMCs, small interfering RNA (siRNA) targeting OGR1 (OGR1-siRNA) was transfected to the cells and non-targeting siRNA (NT-siRNA) was used as a control.

Results

Co and Ni both significantly increased IL-6 secretion in human BSMCs at 300 μM. This significant increase in IL-6 mRNA expression was observed 5 hours after stimulation. BSMCs transfected with OGR1-siRNA produced less IL-6 than BSMCs transfected with NT-siRNA in response to either Co or Ni stimulation. DEX inhibited Co- and Ni-stimulated IL-6 secretion by human BSMCs as well as pH 6.3-stimulated IL-6 secretion in a dose-dependent manner. DEX did not decrease phosphorylation of ERK1/2, p38 MAP kinase, and NF-κB p65 induced by either Co or Ni stimulation.

Conclusion

Co and Ni induce secretion of IL-6 in human BSMCs through activation of OGR1. Co- and Ni-stimulated IL-6 secretion is inhibited by DEX.

Correlation study of cytokine levels in alveolar lavage fluid with exhaled nitric oxide and lung function in children with bronchial asthma

BACKGROUND

The associations between cytokines in the bronchoalveolar lavage fluid (BALF), lung cytokine expression, fractional exhaled nitric oxide (FeNO) and pulmonary function test results in pediatric asthmatics have not been extensively characterized. This study sought to explore correlations between cytokines BALF, FeNO, and pulmonary function test results.

METHODS

From October 2018 to October 2020, a prospective study was conducted on 42 children with asthma and 17 children with pulmonary foreign bodies that required bronchoscopy. Pulmonary function tests and FeNO tests were performed on all patients. Patients were divided into a high FeNO group or low FeNO group based on their FeNO results. Interleukin (IL)-4, IL-5, IL-6, IL-8, IL-13, and IL-17 in the BALF were measured by enzyme-linked immunosorbent assays. Pearson correlations were used to assess the correlations between the cytokines in BALF, the pulmonary function test results, and the FeNO results. Pearson correlation was used to calculate the correlation coefficient "r" among alveolar lavage fluid cytokines, lung function, and FeNO. Receiver operating characteristic (ROC) curves were used to determine the area under the curve (AUC), sensitivity, and specificity of BALF cytokines for the high and low FeNO groups.

RESULTS

IL-4, IL-5, IL-6, IL-8, IL-13, and IL-17 in BALF were significantly correlated with FeNO, but were not significantly correlated with the pulmonary function test results. Cytokine IL-4, IL-5, IL-6, IL-8, IL-13, and IL-17 in BALF were significantly different in the high FeNO, low FeNO, and control groups (all P<0.05). The AUCs for differentiating between low and high FeNO based on BALF cytokines ranged from 0.72 to 0.95. The sensitivity and specificity for discriminating between low and high FeNO based on IL-5 and IL-13 reached 95.7% and 100%, respectively.

CONCLUSIONS

The cytokine levels of the BALF of children with asthma were significantly elevated, correlated with FeNO, and can be used evaluate airway inflammation in children with asthma.

Mechanisms and biomarkers of airway epithelial cell damage in asthma: A review

Bronchial asthma is a heterogeneous disease with complex pathological mechanisms representing different phenotypes, including severe asthma. The airway epithelium is a major site of complex pathological changes in severe asthma due, in part, to activation of inflammatory and immune mechanisms in response to noxious agents. Current imaging procedures are unable to accurately measure epithelial and airway remodeling. Damage of airway epithelial cells occurs is linked to specific phenotypes and endotypes which provides an opportunity for the identification of biomarkers reflecting epithelial, and airway, remodeling. Identification of patients with more severe epithelial disruption using biomarkers may also provide personalised therapeutic opportunities and/or markers of successful therapeutic intervention. Here, we review the evidence for ongoing epithelial cell dysregulation in the pathogenesis of asthma, the sentinel role of the airway epithelium and how understanding these molecular mechanisms provides the basis for the identification of candidate biomarkers for asthma prediction, prevention, diagnosis, treatment and monitoring.

Increased IL-6 and Potential IL-6 trans-signalling in the airways after an allergen challenge

BACKGROUND

In asthma, IL-6 is a potential cause of enhanced inflammation, tissue damage and airway dysfunction. IL-6 signalling is regulated by its receptor, which is composed of two proteins, IL-6R and GP130. In addition to their membrane form, these two proteins may be found as extracellular soluble forms. The interaction of IL-6 with soluble IL-6R (sIL-6R) can trigger IL-6 trans-signalling in cells lacking IL-6R. Conversely, the soluble form of GP130 (sGP130) competes with its membrane form to inhibit IL-6 trans-signalling.

OBJECTIVES

We aimed to analyse IL-6 trans-signalling proteins in the airways of subjects after an allergen challenge.

METHODS

We used a model of segmental bronchoprovocation with an allergen (SBP-Ag) in human subjects with allergy. Before and 48 h after SBP-Ag, bronchoalveolar lavages (BALs) allowed for the analysis of proteins in BAL fluids (BALFs) by ELISA, and membrane proteins on the surface of BAL cells by flow cytometry. In addition, we performed RNA sequencing (RNA-seq) and used proteomic data to further inform on the expression of the IL-6R subunits by eosinophils, bronchial epithelial cells and lung fibroblasts. Finally, we measured the effect of IL-6 trans-signalling on bronchial fibroblasts, in vitro.

RESULTS

IL-6, sIL-6R, sGP130 and the molar ratio of sIL-6R/sGP130 increased in the airways after SBP-Ag, suggesting the potential for enhanced IL-6 trans-signalling activity. BAL lymphocytes, monocytes and eosinophils displayed IL-6R on their surface and were all possible providers of sIL-6R, whereas GP130 was highly expressed in bronchial epithelial cells and lung fibroblasts. Finally, bronchial fibroblasts activated by IL-6 trans-signalling produced enhanced amounts of the chemokine, MCP-1 (CCL2).

CONCLUSION AND CLINICAL RELEVANCE

After a bronchial allergen challenge, we found augmentation of the elements of IL-6 trans-signalling. Allergen-induced IL-6 trans-signalling activity can activate fibroblasts to produce chemokines that can further enhance inflammation and lung dysfunction.

DZNep attenuates allergic airway inflammation in an ovalbumin-induced murine model

BACKGROUND

Growing evidence shows that enhancer of zeste homolog 2 (EZH2) plays a role in various physiological functions and cancer pathogenesis. However, its contribution to allergic diseases remains controversial. We sought to investigate the role of EZH2 in the pathogenesis of allergic airway inflammation.

METHODS

3-Deazaneplanocin A (DZNep), an indirect inhibitor of EZH2, was administered via intraperitoneal injection in an ovalbumin (OVA)-induced murine model of allergic airway inflammation. The expression of EZH2 in the allergic airway tissues was examined by immunohistochemistry (IHC) and western blot. The inflammatory cell infiltration and the goblet cell hyperplasia in the murine nose and lung were detected by hematoxylin and eosin (H&E) staining and periodic acid-Schiff (PAS) staining. Levels of cytokines, including IL-4, IFN-γ, IL-6, and IL-10, were evaluated in the bronchoalveolar lavage fluid (BALF) using Enzyme-linked immune sorbent assay (ELISA).

RESULTS

EZH2 expression was inhibited by DZNep treatment (P < 0.05). The administration of DZNep significantly inhibited the inflammatory cell infiltration (P < 0.0001) and goblet cell hyperplasia (P < 0.001). Moreover, it suppressed the secretion of IL-4 (P < 0.0001) and IL-6 (P < 0.01) in the BALF.

CONCLUSIONS

Our findings demonstrate that DZNep attenuates allergic airway inflammation and could be a new therapeutic option for allergic rhinitis and asthma.

The association of asthma and its subgroups with osteoporosis: a cross-sectional study using KoGES HEXA data

Background

A few studies have reported the association between asthma and osteoporosis. We aimed to analyze the association of asthma and its subgroups with osteoporosis in the Korean adult population.

Methods

We used the health examinee (HEXA) data from the Korean Genome and Epidemiology Study (KoGES) obtained between 2004 and 2016. We included 162,579 participants (n = 3,160 with asthma; n = 159,419 controls) who reported their previous histories of asthma and osteoporosis. The participants were categorized into 3 groups based on asthma management: participants who did not need further treatment due to controlled symptoms (well controlled); participants with ongoing treatment (being treated); participants who were not treated even though they had symptoms (not being treated). Multiple logistic regression analyses were used to calculate the adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for osteoporosis. Subgroup analyses for age and sex were conducted.

Results

The prevalence of osteoporosis was higher in patients with asthma (13.6%) than in controls (6.8%). In the full-adjusted model, the aORs for osteoporosis were 1.74 (95% CI 1.55-1.94, P < 0.001) in patients with asthma compared to controls. There were consistent findings across the age and sex subgroups. The aORs for osteoporosis were 1.43 (95% CI 1.10-1.86, P = 0.008) in the well-controlled asthma group; 1.55 (95% CI 1.28-1.89, P < 0.001) in the being treated asthma group; and 1.96 (95% CI 1.66-2.31, P < 0.001) in the not being treated asthma group compared to the control group.

Conclusion

Asthma was associated with osteoporosis in the Korean adult population. Patients with asthma not being treated showed the highest ORs for osteoporosis.

New Targeted Therapies for Uncontrolled Asthma

Mechanistic studies have improved our understanding of molecular and cellular components involved in asthma and our ability to treat severe patients. An mAb directed against IgE (omalizumab) has become an established add-on therapy for patients with uncontrolled allergic asthma and mAbs specific for IL-5 (reslizumab, mepolizumab), IL-5R (benralizumab), and IL-4R (dupilumab) have been approved as add-on treatments for uncontrolled eosinophilic (type 2) asthma. While these medications have proven highly effective, some patients with severe allergic and/or eosinophilic asthma, as well as most patients with severe non-type-2 disease, have poorly controlled disease. Agents that have recently been evaluated in clinical trials include an antibody directed against thymic stromal lymphopoietin, small molecule antagonists to the chemoattractant receptor-homologous molecule expressed on T_H2 cells (CRTH2) and the receptor for stem cell factor on mast cells (KIT), and a DNA enzyme directed at GATA3. Antibodies to IL-33 and its receptor, ST2, are being evaluated in ongoing clinical studies. In addition, a number of antagonists directed against other potential targets are under consideration for future trials, including IL-25, IL-6, TNF-like ligand 1A, CD6, and activated cell adhesion molecule (ALCAM). Clinical data from ongoing and future trials will be important in determining whether these new medications will offer benefits in place of or in addition to existing therapies for asthma.

Gene-Environment Interaction between the IL1RN Variants and Childhood Environmental Tobacco Smoke Exposure in Asthma Risk

(1) Background: Variants of the interleukin-1 receptor antagonist (IL1RN) gene, encoding an anti-inflammatory cytokine, are associated with asthma. Asthma is a chronic inflammatory disease of the airway influenced by interactions between genetic variants and environmental factors. We discovered a gene-environment interaction (GEI) of IL1RN polymorphisms with childhood environmental tobacco smoke (ETS) exposure on asthma susceptibility in an urban adult population. (2) Methods: DNA samples from the NYU/Bellevue Asthma Registry were genotyped for tag SNPs in IL1RN in asthma cases and unrelated healthy controls. Logistic regressions were used to study the GEI between IL1RN variants and childhood ETS exposures on asthma and early onset asthma, respectively, adjusting for population admixture and other covariates. (3) Results: Whereas the rare genotypes of IL1RN SNPs (e.g., GG in SNP rs2234678) were associated with decreased risk for asthma among those without ETS exposure (odds ratio OR = 0.215, p = 0.021), they are associated with increased risk for early onset asthma among those with childhood ETS (OR = 4.467, p = 0.021). (4) Conclusions: We identified a GEI between polymorphisms of IL1RN and childhood ETS exposure in asthma. Analysis of GEI indicated that childhood ETS exposure disrupted the protective effect of some haplotypes/genotypes of IL1RN for asthma and turned them into high-risk polymorphisms for early onset asthma.

Mechanisms and therapeutic strategies for non-T2 asthma

Non-T2 asthma is traditionally defined as asthma without features of T2 asthma. The definition is arbitrary and is generally based on the presence of neutrophils in sputum, or the absence (or normal levels) of eosinophils or other T2 markers in sputum (paucigranulocytic), airway biopsies or in blood. This definition may be imprecise as we gain more knowledge from applying transcriptomics and proteomics to blood and airway samples. The prevalence of non-T2 asthma is also difficult to estimate as most studies are cross-sectional and influenced by concomitant treatment with glucocorticosteroids, and by the presence of recognized or unrecognized airway infections. No specific therapies have shown any clinical benefits in patients with asthma that is associated with a non-T2 inflammatory process. It remains to be seen if such an endotype truly exists and to identify treatments to target that endotype. Meanwhile, identifying intense airway neutrophilia as an indicator of airway infection and airway hyperresponsiveness as an indicator of smooth muscle dysfunction, and treating them appropriately, and not increasing glucocorticosteroids in patients who do not have obvious T2 inflammation, seem reasonable.

Apolipoprotein A-IV acts as an endogenous anti-inflammatory protein and is reduced in treatment-naïve allergic patients and allergen-challenged mice

Background

Recent studies pointed to a crucial role for apolipoproteins in the pathogenesis of inflammatory diseases. However, the role of apolipoprotein‐IV (ApoA‐IV) in allergic inflammation has not been addressed thoroughly thus far.

Objective

Here, we explored the anti‐inflammatory effects and underlying signaling pathways of ApoA‐IV on eosinophil effector function in vitro and in vivo.

Methods

Migratory responsiveness, Ca²⁺‐flux and apoptosis of human peripheral blood eosinophils were assessed in vitro. Allergen‐driven airway inflammation was assessed in a mouse model of acute house dust mite‐induced asthma. ApoA‐IV serum levels were determined by ELISA.

Results

Recombinant ApoA‐IV potently inhibited eosinophil responsiveness in vitro as measured by Ca²⁺‐flux, shape change, integrin (CD11b) expression, and chemotaxis. The underlying molecular mechanism involved the activation of Rev‐ErbA‐α and induced a PI3K/PDK1/PKA‐dependent signaling cascade. Systemic application of ApoA‐IV prevented airway hyperresponsiveness (AHR) and airway eosinophilia in mice following allergen challenge. ApoA‐IV levels were decreased in serum from allergic patients compared to healthy controls.

Conclusion

Our data suggest that ApoA‐IV is an endogenous anti‐inflammatory protein that potently suppresses effector cell functions in eosinophils. Thus, exogenously applied ApoA‐IV may represent a novel pharmacological approach for the treatment of allergic inflammation and other eosinophil‐driven disorders.

Severe exacerbations in moderate-to-severe asthmatics are associated with increased pro-inflammatory and type 1 mediators in sputum and serum

BACKGROUND

Asthma is a heterogeneous disease and understanding this heterogeneity will enable the realisation of precision medicine. We sought to compare the sputum and serum inflammatory profiles in moderate-to-severe asthma during stable disease and exacerbation events.

METHODS

We recruited 102 adults and 34 children with asthma. The adults were assessed at baseline, 3, 6, and 12-month follow-up visits. Thirty-seven subjects were assessed at onset of severe exacerbation. Forty sputum mediators and 43 serum mediators were measured. Receiver-operator characteristic (ROC) curves were constructed to identify mediators that distinguish between stable disease and exacerbation events. The strongest discriminating sputum mediators in the adults were validated in the children.

RESULTS

The mediators that were significantly increased at exacerbations versus stable disease and by ≥1.5-fold were sputum IL-1β, IL-6, IL-6R, IL-18, CXCL9, CXCL10, CCL5, TNFα, TNF-R1, TNF-R2, and CHTR and serum CXCL11. No mediators decreased ≥1.5-fold at exacerbation. The strongest discriminators of an exacerbation in adults (ROC area under the curve [AUC]) were sputum TNF-R2 0.69 (95% CI: 0.60 to 0.78) and IL-6R 0.68 (95% CI: 0.58 to 0.78). Sputum TNF-R2 and IL-6R were also discriminatory in children (ROC AUC 0.85 [95% CI: 0.71 to 0.99] and 0.80 [0.64 to 0.96] respectively).

CONCLUSIONS

Severe asthma exacerbations are associated with increased pro-inflammatory and Type 1 (T1) immune mediators. In adults, sputum TNF-R2 and IL-6R were the strongest discriminators of an exacerbation, which were verified in children.

Molecular changes during TGFβ-mediated lung fibroblast-myofibroblast differentiation: implication for glucocorticoid resistance

Airway remodeling is an important process in response to repetitive inflammatory-mediated airway wall injuries. This is characterized by profound changes and reorganizations at the cellular and molecular levels of the lung tissue. It is of particular importance to understand the mechanisms involved in airway remodeling, as this is strongly associated with severe asthma leading to devastating airway dysfunction. In this study, we have investigated the transforming growth factor-β (TGFβ, a proinflammatory mediator)-activated fibroblast to myofibroblast transdifferentiation pathway, which plays a key role in asthma-related airway remodeling. We show that TGFβ induces fibroblast to myofibroblast transdifferentiation by the expression of αSMA, a specific myofibroblast marker. Furthermore, Smad2/Smad3 gene and protein expression patterns are different between fibroblasts and myofibroblasts. Such a change in expression patterns reveals an important role of these proteins in the cellular phenotype as well as their regulation by TGFβ during cellular transdifferentiation. Interestingly, our data show a myofibroblastic TGFβ-mediated increase in glucocorticoid receptor (GR) expression and a preferential localization of GR in the nucleus, compared to in fibroblasts. Furthermore, the GRβ (nonfunctional GR isoform) is increased relative to GRα (functional isoform) in myofibroblasts. These results are interesting as they support the idea of a GRβ-mediated glucocorticoid resistance observed in the severe asthmatic population. All together, we provide evidence that key players are involved in the TGFβ-mediated fibroblast to myofibroblast transdifferentiation pathway in a human lung fibroblast cell line. These players could be the targets of new treatments to limit airway remodeling and reverse glucocorticoid resistance in severe asthma.

Targeting Cytokines as Evolving Treatment Strategies in Chronic Inflammatory Airway Diseases

Cytokines are key players in the initiation and propagation of inflammation in chronic inflammatory airway diseases such as chronic obstructive pulmonary disease (COPD), bronchiectasis and allergic asthma. This makes them attractive targets for specific novel anti-inflammatory treatment strategies. Recently, both interleukin-1 (IL-1) and IL-6 have been associated with negative health outcomes, mortality and a pro-inflammatory phenotype in COPD. IL-6 in COPD was shown to correlate negatively with lung function, and IL-1beta was induced by cigarette smoke in the bronchial epithelium, causing airway inflammation. Furthermore, IL-8 has been shown to be a pro-inflammatory marker in bronchiectasis, COPD and allergic asthma. Clinical trials using specific cytokine blockade therapies are currently emerging and have contributed to reduce exacerbations and steroid use in COPD. Here, we present a review of the current understanding of the roles of cytokines in the pathophysiology of chronic inflammatory airway diseases. Furthermore, outcomes of clinical trials in cytokine blockade as novel treatment strategies for selected patient populations with those diseases will be discussed.

Influence of weight loss on pulmonary function and levels of adipokines among asthmatic individuals with obesity: One-year follow-up

BACKGROUND

Individuals with obesity are more likely to develop asthma, but the exact mechanism is still uncertain and several hypotheses have been raised, such as the release of inflammatory mediators secreted by adipose tissue.

OBJECTIVE

To assess the effects of weight loss in patients submitted to bariatric surgery on pulmonary and systemic inflammation.

METHOD

The study evaluated patients undergoing bariatric surgery (Roux-en-Y gastric bypass) with the diagnosis of asthma, except smokers. The patients were evaluated at the time of entry into a preoperative weight loss group (T1), just before bariatric surgery (T2), six months after surgery (T3), and 12 months after surgery (T4). The following were measured: anthropometric data, dosage of systemic inflammatory markers by means of blood collection, pulmonary inflammatory markers obtained by induced sputum collection, pulmonary function parameters, and asthma activity assessed by a Asthma Control Test (ACT) questionnaire.

RESULTS

Nineteen patients participated in the study. There were significant reductions in the systemic levels of interleukin (IL)-8 (p = 0.002), C-reactive protein (CRP) (p = 0.003), leptin (p = 0.001) and tumor necrosis factor (TNF)-α (p = 0.007), and significant increase in the systemic levels of IL-6 (p = 0.004) over time and adiponectin in T2 (p = 0.025). In regards to pulmonary inflammation, there were significant reductions in the sputum levels of TNF-α (p < 0.001). There was no significant improvement of the pulmonary function parameters (p > 0.05) and significant improvement in asthma activity scores (p < 0.0001).

CONCLUSION

Weight loss was associated with significant changes in the systemic and pulmonary inflammatory profiles of individuals with asthma, leading to a better asthma control as a result of an increase in some anti-inflammatory mediators and a reduction of pro-inflammatory mediators.

Comparative Immunomodulatory Activity of Nigella sativa L. Preparations on Proinflammatory Mediators: A Focus on Asthma

Introduction: A range of traditional and commercial preparations of NS is frequently used in the treatment of several inflammatory diseases. Often, these preparations have poor preclinical characterization that may lead to variable pharmacological effects. Objective: To assess the in vitro effects of different chemically defined preparations of NS on some asthma-related mediators of inflammation. Methods: Different NS preparations were obtained by either seed extraction with a spectrum of solvents ranging from lipophilic to hydrophilic, or commercial products were collected. The TQ concentration of NS was analyzed by HPLC. Immunomodulatory activity was assessed by the release of mediators (IL-2, IL-6, PGE2) in primary human T-lymphocytes, monocytes, and A549 human lung epithelial cells. Results: Ten distinct NS preparations showed variability in TQ concentration, being highest in the oily preparations extract-7 (2.4% w/w), followed by extract-10 (0.7%w/w). Similarly, the release of mediators was varied, being greatest in extract-7 and 10 via significantly (<0.05) suppressing IL-2, IL-6, and PGE2 in T-lymphocytes as well as IL-6 and PGE2 in monocytes. Also, PGE2 release in A549 cells was significantly enhanced by both extracts. Conclusion: The TQ concentration and in vitro activity were variable among the different NS preparations. TQ-rich oily NS preparations produced potent favorable immunomodulation in asthma inflammation and can be used in future studies.

Nebivolol attenuates oxidative stress and inflammation in a guinea pig model of ovalbumin-induced asthma: a possible mechanism for its favorable respiratory effects

An experimental model of ovalbumin (OVA) induced asthma was used to assess the effects of nebivolol, the third-generation selective β₁-adrenergic receptor blocker, on airway reactivity, lung inflammation, and oxidative stress markers. The asthma induction protocol was done by OVA sensitization and challenge. Guinea pigs were classified into control, asthmatic, or asthmatic receiving nebivolol either 7.5 or 15 mg·kg^-1·day^-1 orally. At the end of the study respiratory, the anti-inflammatory and antioxidative effects of nebivolol were assessed. The asthmatic group exhibited a significant increase in early and late airway resistance, airway hyperreactivity to histamine, total and absolute leucocytic count, tumor necrosis factor-α, and interleukin-6 in bronchoalveolar lavage fluid and lung lipid peroxidation and a significant decrease in superoxide dismutase and glutathione compared to the control group. Additionally, there was a significant decrease in lung endothelial nitric oxide synthase (eNOS) and a significant increase in inducible nitric oxide synthase (iNOS) mRNA expression compared to the control group. The high dose of nebivolol counteracted the increased airway resistance induced by OVA, whereas it had no effect on airway hyperresponsiveness. Moreover, nebivolol exhibited significant anti-inflammatory and antioxidant effects and restored the altered levels of eNOS and iNOS compared to the asthmatic group. Collectively, these results suggest a beneficial effect of nebivolol in asthma.

Inflammasome in the Pathogenesis of Pulmonary Diseases

Lung diseases are common and significant causes of illness and death around the world. Inflammasomes have emerged as an important regulator of lung diseases. The important role of IL-1 beta and IL-18 in the inflammatory response of many lung diseases has been elucidated. The cleavage to turn IL-1 beta and IL-18 from their precursors into the active forms is tightly regulated by inflammasomes. In this chapter, we structurally review current evidence of inflammasome-related components in the pathogenesis of acute and chronic lung diseases, focusing on the "inflammasome-caspase-1-IL-1 beta/IL-18" axis.

Induction of Human Lung Mast Cell Apoptosis by Granule Permeabilization: A Novel Approach for Targeting Mast Cells

Mast cells are implicated as detrimental players in inflammatory lung diseases, particularly asthma. Mast cells respond to activating stimuli by releasing a wide panel of pro-inflammatory compounds that can contribute profoundly to the pathology, and there is currently an unmet need for strategies that efficiently ameliorate harmful effects of mast cells under such conditions. Here, we sought to evaluate a novel concept for targeting human lung mast cells, by assessing the possibility of selectively depleting the lung mast cells by induction of apoptosis. For this purpose, we used lysosomotropic agents, i.e., compounds that are known to permeabilize the secretory granules of mast cells, thereby releasing the contents of the granules into the cytosol. Either intact human lung tissue, purified human lung mast cells or mixed populations of human lung cells were incubated with the lysosomotropic agents mefloquine or siramesine, followed by measurement of apoptosis, reactive oxygen species (ROS) production, and release of cytokines. We show that human lung mast cells were highly susceptible to apoptosis induced by this strategy, whereas other cell populations of the lung were largely refractory. Moreover, we demonstrate that apoptosis induced by this mode is dependent on the production of ROS and that the treatment of lung tissue with lysosomotropic agents causes a decrease in the release of pathogenic cytokines. We conclude that selective apoptosis of human lung mast cells can be accomplished by administration of lysosomotropic agents, thus introducing the possibility of using such drugs as novel therapeutics in the treatment of inflammatory lung disorders such as asthma.

Intranasal administration of recombinant progranulin inhibits bronchial smooth muscle hyperresponsiveness in mouse allergic asthma

Progranulin (PGRN) is a growth factor with multiple biological functions and has been suggested as an endogenous inhibitor of Tumor necrosis factor-α (TNF-α)-mediated signaling. TNF-α is believed to be one of the important mediators of the pathogenesis of asthma, including airway hyperresponsiveness (AHR). In the present study, effects of recombinant PGRN on TNF-α-mediated signaling and antigen-induced hypercontractility were examined in bronchial smooth muscles (BSMs) both in vitro and in vivo. Cultured human BSM cells (hBSMCs) and male BALB/c mice were used. The mice were sensitized and repeatedly challenged with ovalbumin antigen. Animals also received intranasal administrations of recombinant PGRN into the airways 1 h before each antigen inhalation. In hBSMCs, PGRN inhibited both the degradation of IκB-α (an index of NF-κB activation) and the upregulation of RhoA (a contractile machinery-associated protein that contributes to the BSM hyperresponsiveness) induced by TNF-α, indicating that PGRN has an ability to inhibit TNF-α-mediated signaling also in the BSM cells. In BSMs of the repeatedly antigen-challenged mice, an augmented contractile responsiveness to acetylcholine with an upregulation of RhoA was observed: both the events were ameliorated by pretreatments with PGRN intranasally. Interestingly, a significant decrease in PGRN expression was found in the airways of the repeatedly antigen-challenged mice rather than those of control animals. In conclusion, exogenously applied PGRN into the airways ameliorated the antigen-induced BSM hyperresponsiveness, probably by blocking TNF-α-mediated response. Increasing PGRN levels might be a promising therapeutic for AHR in allergic asthma.

Self-reported racial/ethnic discrimination and bronchodilator response in African American youth with asthma

IMPORTANCE

Asthma is a multifactorial disease composed of endotypes with varying risk profiles and outcomes. African Americans experience a high burden of asthma and of psychosocial stress, including racial discrimination. It is unknown which endotypes of asthma are vulnerable to racial/ethnic discrimination.

OBJECTIVE

We examined the association between self-reported racial/ethnic discrimination and bronchodilator response (BDR) among African American youth with asthma ages 8 to 21 years (n = 576) and whether this association varies with tumor necrosis factor alpha (TNF-α) level.

MATERIALS AND METHODS

Self-reported racial/ethnic discrimination was assessed by a modified Experiences of Discrimination questionnaire as none or any. Using spirometry, BDR was specified as the mean percentage change in forced expiratory volume in one second before and after albuterol administration. TNF-α was specified as high/low levels based on our study population mean. Linear regression was used to examine the association between self-reported racial/ethnic discrimination and BDR adjusted for selected characteristics. An interaction term between TNF-α levels and self-reported racial/ethnic discrimination was tested in the final model.

RESULTS

Almost half of participants (48.8%) reported racial/ethnic discrimination. The mean percent BDR was higher among participants reporting racial/ethnic discrimination than among those who did not (10.8 versus 8.9, p = 0.006). After adjustment, participants reporting racial/ethnic discrimination had a 1.7 (95% CI: 0.36-3.03) higher BDR mean than those not reporting racial/ethnic discrimination. However, we found heterogeneity of this association according to TNF-α levels (p-interaction = 0.040): Among individuals with TNF-α high level only, we observed a 2.78 higher BDR mean among those reporting racial/ethnic discrimination compared with those not reporting racial/ethnic discrimination (95%CI: 0.79-4.77).

CONCLUSIONS

We found BDR to be increased in participants reporting racial/ethnic discrimination and this association was limited to African American youth with TNF-α high asthma, an endotype thought to be resistant to traditional asthma medications. These results support screening for racial/ethnic discrimination in those with asthma as it may reclassify disease pathogenesis.

Interleukin-17A directly acts on bronchial smooth muscle cells and augments the contractility

BACKGROUND

Although interleukin-17 (IL-17) contributes to the induction of airway hyperresponsiveness in asthma, its effect on bronchial smooth muscle (BSM) remains largely unknown. Evidence support an involvement of RhoA/Rho-kinase in BSM contraction, and the pathway has now been proposed as a novel target for asthma therapy. To clarify the role of IL-17 on the development of BSM hyperresponsiveness, effects of IL-17A on BSM contractility and RhoA expression were investigated.

METHODS

Male BALB/c mice and cultured human BSM cells (hBSMCs) were used.

RESULTS

In the murine model of allergic asthma, BSM hyperresponsiveness with an IL-17A up-regulation in bronchoalveolar lavage fluids were observed. RT-PCR analyses revealed the expression of receptors for IL-17A in mouse BSMs and hBSMCs. In the hBSMCs, incubation with IL-17A caused an up-regulation of RhoA protein. Western blot analyses also revealed phosphorylations of JNKs/ERKs and a down-regulation of IκB-α in the IL-17A-treated hBSMCs, indicating that IL-17A could act on BSM cells directly. However, IL-17A did not activate STAT6, which is also known as a signaling molecule that causes an up-regulation of RhoA when activated by IL-13. On the other hand, IL-17A caused a down-regulation of miR-133a-3p, a microRNA that negatively regulates RhoA translation. In the naive mice, in vivo IL-17A treatment to the airways by intranasal instillation induced a BSM hyperresponsiveness with RhoA protein up-regulation.

CONCLUSIONS

These findings indicate that IL-17 directly acts on BSM cells and up-regulates RhoA protein probably via a down-regulation of miR-133a-3p, resulting in an induction of the BSM hyperresponsiveness.

Cytotoxic effects of composite dust on human bronchial epithelial cells

INTRODUCTION

Previous research revealed that during routine abrasive procedures like polishing, shaping or removing of composites, high amounts of respirable dust particles (<5μm) including nano-sized particles (<100nm) may be released.

OBJECTIVE

To determine the cytotoxic potential of composite dust particles on bronchial epithelium cells.

METHODS

Composite dust of five commercial composites (one nano-composite, two nano-hybrid and two hybrid composites) was generated following a clinically relevant protocol. Polymerized composite samples were cut with a rough diamond bur (grain size 100μm, speed 200,000rpm) and all composite dust was collected in a sterile chamber. Human bronchial epithelial cells (16HBE14o-) were exposed to serially diluted suspensions of composite dust in cell culture medium at concentrations between 1.1 and 3.3mg/ml. After 24h-exposure, cell viability and membrane integrity were assessed by the WST-1 and the LDH leakage assay, respectively. The release of IL-1β and IL-6 was evaluated. The composite dust particles were characterized by transmission electron microscopy and by dynamic and electrophoretic light scattering.

RESULTS

Neither membrane damage nor release of IL-1β was detected over the complete concentration range. However, metabolic activity gradually declined for concentrations higher than 660μg/ml and the release of IL-6 was reduced when cells were exposed to the highest concentrations of dust.

SIGNIFICANCE

Composite dust prepared by conventional dental abrasion methods only affected human bronchial epithelial cells in very high concentrations.

Patient stratification and the unmet need in asthma

Asthma is often described as an inflammatory disease of the lungs and in most patients symptomatic treatment with bronchodilators or inhaled corticosteroids is sufficient to control disease. Unfortunately there are a proportion of patients who fail to achieve control despite treatment with the best current treatment. These severe asthma patients have been considered a homogeneous group of patients that represent the unmet therapeutic need in asthma. Many novel therapies have been tested in unselected asthma patients and the effects have often been disappointing, particularly for the highly specific monoclonal antibody-based drugs such as anti-IL-13 and anti-IL-5. More recently, it has become clear that asthma is a syndrome with many different disease drivers. Clinical trials of anti-IL-13 and anti-IL-5 have focused on biomarker-defined patient groups and these trials have driven the clinical progression of these drugs. Work on asthma phenotyping indicates that there is a group of asthma patients where T helper cell type 2 (Th2) cytokines and inflammation predominate and these type 2 high (T2-high) patients can be defined by biomarkers and response to therapies targeting this type of immunity, including anti-IL-5 and anti-IL-13. However, there is still a subset of T2-low patients that do not respond to these new therapies. This T2-low group will represent the new unmet medical need now that the T2-high-targeting therapies have made it to the market. This review will examine the current thinking on patient stratification in asthma and the identification of the T2-high subset. It will also look at the T2-low patients and examine what may be the drivers of disease in these patients.

Pulmonary surfactant mitigates silver nanoparticle toxicity in human alveolar type-I-like epithelial cells

Accompanying increased commercial applications and production of silver nanomaterials is an increased probability of human exposure, with inhalation a key route. Nanomaterials that deposit in the pulmonary alveolar region following inhalation will interact firstly with pulmonary surfactant before they interact with the alveolar epithelium. It is therefore critical to understand the effects of human pulmonary surfactant when evaluating the inhalation toxicity of silver nanoparticles. In this study, we evaluated the toxicity of AgNPs on human alveolar type-I-like epithelial (TT1) cells in the absence and presence of Curosurf(®) (a natural pulmonary surfactant substitute), hypothesising that the pulmonary surfactant would act to modify toxicity. We demonstrated that 20nm citrate-capped AgNPs induce toxicity in human alveolar type I-like epithelial cells and, in agreement with our hypothesis, that pulmonary surfactant acts to mitigate this toxicity, possibly through reducing AgNP dissolution into cytotoxic Ag(+) ions. For example, IL-6 and IL-8 release by TT1 cells significantly increased 10.7- and 35-fold, respectively (P<0.01), 24h after treatment with 25μg/ml AgNPs. In contrast, following pre-incubation of AgNPs with Curosurf(®), this effect was almost completely abolished. We further determined that the mechanism of this toxicity is likely associated with Ag(+) ion release and lysosomal disruption, but not with increased reactive oxygen species generation. This study provides a critical understanding of the toxicity of AgNPs in target human alveolar type-I-like epithelial cells and the role of pulmonary surfactant in mitigating this toxicity. The observations reported have important implications for the manufacture and application of AgNPs, in particular for applications involving use of aerosolised AgNPs.

Interleukin 6 SNP rs1800797 associates with the risk of adult-onset asthma

Interleukin 6 (IL6) is an inflammatory cytokine that has been suggested to have an important role in the pathogenesis of asthma. IL6 single-nucleotide polymorphisms (SNPs) have been associated with levels of IL6, and with childhood and prevalent adult asthma. A recent study also suggested that IL6 SNPs associate especially with atopic asthma. However, association of IL6 SNPs with adult-onset asthma has not been studied. In a population-based study of 467 incident adult-onset asthma cases and 613 disease-free controls from South Finland, we analyzed association of 6 tagging SNPs of the IL6 locus with the risk of adult-onset asthma and with atopy. Asthma was clinically diagnosed, and atopy was defined based on Phadiatop test. IL6 SNP rs1800797 associated with the risk of adult-onset asthma in a log additive model, with adjusted odds ratio (aOR) 1.31 (95% confidence interval 1.09-1.57), and especially with the risk of atopic adult-onset asthma when compared with non-atopic controls, aOR 1.46 (95% CI 1.12-1.90). This is the first study to show an association of IL6 with adult-onset asthma, and especially with atopic adult-onset asthma.

Thrombin-induced IL-8/CXCL8 release is mediated by CK2, MSK1, and NF-κB pathways in human lung epithelial cells

Airway inflammation plays a major role in the pathophysiology of lung inflammatory diseases such as asthma. Thrombin, a serine protease, is known to mediate central functions in thrombosis and hemostasis and also plays a critical role in lung inflammation via producing chemokine release including interleukin (IL)-8/CXCL8. Our previous studies showed that c-Src- and Rac-dependent nuclear factor (NF)-κB signaling pathways participate in thrombin-induced IL-8/CXCL8 release in human lung epithelial cells. In this study, we further investigated the role of casein kinase 2 (CK2)/mitogen stress-activated protein kinase 1 (MSK1)-dependent p65 phosphorylation in thrombin-induced NF-κB activation and IL-8/CXCL8 release. Thrombin-induced IL-8/CXCL8 release was inhibited by CK2 inhibitors (apigenin and tetrabromobenzotriazole, TBB), small interfering RNA of CK2β (CK2β siRNA), and MSK1 siRNA. Treatment of cells with thrombin caused increases in CK2β phosphorylation at Ser209, which was inhibited by a protein kinase C α (PKCα) inhibitor (Ro-32-0432). Thrombin-induced MSK1 phosphorylation at Ser581 and Akt phosphorylation at Ser473 were inhibited by apigenin. Moreover, the thrombin-induced increase in IL-8/CXCL8 release was attenuated by p65 siRNA. Stimulation of cells with thrombin resulted in an increase in p65 phosphorylation at Ser276, which was inhibited by apigenin and MSK1 siRNA. Thrombin-induced κB-luciferase activity was also inhibited by apigenin and MSK1 siRNA. Taken together, these results show that thrombin activates the PKCα/CK2/MSK1 signaling pathways, which in turn initiates p65 phosphorylation and NF-κB activation, and ultimately induces IL-8/CXCL8 release in human lung epithelial cells.

Prevention of Influenza Virus-Induced Immunopathology by TGF-β Produced during Allergic Asthma

Asthma is believed to be a risk factor for influenza infection, however little experimental evidence exists to directly demonstrate the impact of asthma on susceptibility to influenza infection. Using a mouse model, we now report that asthmatic mice are actually significantly more resistant to a lethal influenza virus challenge. Notably, the observed increased resistance was not attributable to enhanced viral clearance, but instead, was due to reduced lung inflammation. Asthmatic mice exhibited a significantly reduced cytokine storm, as well as reduced total protein levels and cytotoxicity in the airways, indicators of decreased tissue injury. Further, asthmatic mice had significantly increased levels of TGF-β1 and the heightened resistance of asthmatic mice was abrogated in the absence of TGF-β receptor II. We conclude that a transient increase in TGF-β expression following acute asthma can induce protection against influenza-induced immunopathology.

Influenza and asthma represent the two major lung diseases in humans. While most studies have focused on exacerbation of asthma symptoms by influenza virus infection, the effects of asthma on susceptibility to influenza virus infections has been far less studied. Using a novel mouse model of asthma and influenza infection, we show that asthmatic mice are highly resistant to primary challenge with the 2009 influenza pandemic strain (CA04) compared to non-asthmatic mice. The increased resistance of asthmatic mice is not due to the enhanced T or B cell immunity but rather, to a strong anti-inflammatory TGF-beta response triggered by asthma. This study is the first to provide a mechanistic explanation for asthma-mediated protection during the 2009 influenza pandemic.

Obesity and bronchodilator response in black and Hispanic children and adolescents with asthma

BACKGROUND

Obesity is associated with poor asthma control, increased asthma morbidity, and decreased response to inhaled corticosteroids. We hypothesized that obesity would be associated with decreased bronchodilator responsiveness in children and adolescents with asthma. In addition, we hypothesized that subjects who were obese and unresponsive to bronchodilator would have worse asthma control and would require more asthma controller medications.

METHODS

In the Study of African Americans, Asthma, Genes, and Environments (SAGE II) and the Genes-environments and Admixture in Latino Americans (GALA II) study, two identical, parallel, case-control studies of asthma, we examined the association between obesity and bronchodilator response in 2,963 black and Latino subjects enrolled from 2008 to 2013 using multivariable logistic regression. Using bronchodilator responsiveness, we compared asthma symptoms, controller medication usage, and asthma exacerbations between nonobese (< 95th% BMI) and obese (≥ 95th% BMI) subjects.

RESULTS

The odds of being bronchodilator unresponsive were 24% (OR, 1.24; 95% CI, 1.03-1.49) higher among obese children and adolescents compared with their not obese counterparts after adjustment for age, race/ethnicity, sex, recruitment site, baseline lung function (FEV1/FVC), and controller medication. Bronchodilator-unresponsive obese subjects were more likely to report wheezing (OR, 1.38; 95% CI, 1.13-1.70), being awakened at night (OR, 1.34; 95% CI, 1.09-1.65), using leukotriene receptor inhibitors (OR, 1.33; 95% CI, 1.05-1.70), and using inhaled corticosteroid with long-acting β2-agonist (OR, 1.37; 95% CI, 1.05-1.78) than were their nonobese counterpart. These associations were not seen in the bronchodilator-responsive group.

CONCLUSIONS

Obesity is associated with bronchodilator unresponsiveness among black and Latino children and adolescents with asthma. The findings on obesity and bronchodilator unresponsiveness represent a unique opportunity to identify factors affecting asthma control in blacks and Latinos.

Effect of diosmetin on airway remodeling in a murine model of chronic asthma

Bronchial asthma, one of the most common allergic diseases, is characterized by airway hyperresponsiveness (AHR), inflammation, and remodeling. The anti-oxidant flavone aglycone diosmetin ameliorates the inflammation in pancreatitis, but little is known about its impact on asthma. In this study, the effects of diosmetin on chronic asthma were investigated with an emphasis on the modulation of airway remodeling in BALB/c mice challenged with ovalbumin (OVA). It was found that diosmetin significantly relieved inflammatory cell infiltration, goblet cell hyperplasia, and collagen deposition in the lungs of asthmatic mice and notably reduced AHR in these animals. The OVA-induced increases in total cell and eosinophil counts in bronchoalveolar lavage fluid were reversed, and the level of OVA-specific immunoglobulin E in serum was attenuated by diosmetin administration, implying an anti-Th2 activity of diosmetin. Furthermore, diosmetin remarkably suppressed the expression of smooth muscle actin alpha chain, indicating a potent anti-proliferative effect of diosmetin on airway smooth muscle cells (ASMCs). Matrix metallopeptidase-9, transforming growth factor-β1, and vascular endothelial growth factor levels were also alleviated by diosmetin, suggesting that the remission of airway remodeling might be attributed to the decline of these proteins. Taken together, our findings provided a novel profile of diosmetin with anti-remodeling therapeutic benefits, highlighting a new potential of diosmetin in remitting the ASMC proliferation in chronic asthma.

The development of allergic inflammation in a murine house dust mite asthma model is suppressed by synbiotic mixtures of non-digestible oligosaccharides and Bifidobacterium breve M-16V

Purpose

The incidence and severity of allergic asthma is rising, and novel strategies to prevent or treat this disease are needed. This study investigated the effects of different mixtures of non-digestible oligosaccharides combined with Bifidobacterium breve M-16V (BB) on the development of allergic airway inflammation in an animal model for house dust mite (HDM)-induced allergic asthma.

Methods

BALB/c mice were sensitized intranasally (i.n.) with HDM and subsequently challenged (i.n.) with PBS or HDM while being fed diets containing different oligosaccharide mixtures in combination with BB or an isocaloric identical control diet. Bronchoalveolar lavage fluid (BALF) inflammatory cell influx, chemokine and cytokine concentrations in lung homogenates and supernatants of ex vivo HDM-restimulated lung cells were analyzed.

Results

The HDM-induced influx of eosinophils and lymphocytes was reduced by the diet containing the short-chain and long-chain fructo-oligosaccharides and BB (FFBB). In addition to the HDM-induced cell influx, concentrations of IL-33, CCL17, CCL22, IL-6, IL-13 and IL-5 were increased in supernatants of lung homogenates or BALF and IL-4, IFN-γ and IL-10 were increased in restimulated lung cell suspensions of HDM-allergic mice. The diet containing FFBB reduced IL-6, IFN-γ, IL-4 and IL-10 concentrations, whereas the combination of galacto-oligosaccharides and long-chain fructo-oligosaccharides with BB was less potent in this model.

Conclusion

These findings show that synbiotic dietary supplementation can affect respiratory allergic inflammation induced by HDM. The combination of FFBB was most effective in the prevention of HDM-induced airway inflammation in mice.

Poly(inosinic-cytidylic) acid-triggered exacerbation of experimental asthma depends on IL-17A produced by NK cells

Viral infection of the respiratory tract represents the major cause of acute asthma exacerbations. dsRNA is produced as an intermediate during replication of respiratory viruses and triggers immune responses via TLR3. This study aimed at clarifying the mechanisms underlying TLR3 triggered exacerbation of experimental allergic asthma. The TLR3 ligand poly(inosinic-cytidylic) acid was applied intranasally to mice with already established experimental allergic asthma. Airway inflammation, cytokine expression, mucus production, and airway reactivity was assessed in wild-type, IL-17A, or IL-23p19-deficient, and in NK cell-depleted mice. Local application of poly(inosinic-cytidylic) acid exacerbated experimental allergic asthma in mice as characterized by enhanced release of proinflammatory cytokines, aggravated airway inflammation, and increased mucus production together with pronounced airway hyperresponsiveness. This was further associated with augmented production of IL-17 by Th17 cells and NK cells. Whereas experimental exacerbation could be induced in IL-23p19-deficient mice lacking mature, proinflammatory Th17 cells, this was not possible in mice lacking IL-17A or in NK cell-depleted animals. These experiments indicate a central role for IL-17 derived from NK cells but not from Th17 cells in the pathogenesis of virus-triggered exacerbation of experimental asthma.

Association between polymorphism of interleukin-1 beta and interleukin-1 receptor antagonist gene and asthma risk: a meta-analysis

Background. Asthma is a complex polygenic disease in which gene-environment interactions are important. A number of studies have investigated the polymorphism of IL-1β -511C/T and IL-1RA genes in relation to asthma susceptibility in different populations. However, the results of individual studies have been inconsistent. Accordingly, we conducted a comprehensive meta-analysis to investigate the association between the IL-1β -511C/T and IL-1RA polymorphism and asthma risk. Methods. Data were collected from the following electronic databases: Pub Med, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM), ISI Web of Knowledge, and Google Scholar Search databases with the last report up to July 2013. Finally, 15 studies were included in our meta-analysis. We summarized the data on the association between IL-1β -511C/T and IL-1RA polymorphism and risk of asthma in the overall population and performed subgroup analyses by ethnicity, mean of age, and source of controls. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between IL-1β -511C/T and IL-1RA polymorphism and asthma risk. Statistical analysis was performed with Review Manager 5.1. Results. A total of 15 case-control studies were included in the meta-analysis of IL-1β -511C/T (1,385 cases and 1,964 controls) and IL-1RA (2,800 cases and 6,359 controls) genotypes. No association was found between IL-1β -511C/T polymorphism and asthma risk (dominant model: OR = 1.11, 95% CI: 0.99–1.25, P = 0.07, P_{Heterogeneity} = 0.06; recessive model: OR = 1.04, 95% CI: 0.91–1.20, P = 0.55, P_{Heterogeneity} = 0.11). Subgroup analysis based on ethnicity (Asian and Caucasian), source of controls (population-based controls and hospital-based controls), and mean of age (adulthood and childhood) did not present any significant association. The overall results showed that the IL-1RA polymorphism was related to an increased risk of asthma (homozygote model: OR = 1.32, 95% CI: 1.12–1.56, P = 0.0009, P_{Heterogeneity} = 0.87; recessive model: OR = 1.39, 95% CI: 1.18–1.63, P = 0.0001, P_{Heterogeneity} = 0.82). Similar results were found in the subgroup analyses by ethnicity, mean of age, and source of controls. Sensitivity analysis did not perturb the results. Conclusions. This meta-analysis provided strong evidence that the IL-1RA polymorphism was a risk factor of asthma, especially in Caucasian populations. However, no association was found for IL-1β -511C/T genotype carriers. Larger scale studies are needed for confirmation.