Nasal lavage VEGF and TNF-α levels during a natural cold predict asthma exacerbations

The Efficacy & Molecular Mechanisms of a Terpenoid Compound Ganoderic Acid C1 on Corticosteroid-Resistant Neutrophilic Airway Inflammation: In vivo and in vitro Validation

Introduction

Neutrophil predominant airway inflammation is associated with severe and steroid-resistant asthma clusters. Previously, we reported efficacy of ASHMI, a three-herb TCM asthma formula in a steroid-resistant neutrophil-dominant murine asthma model and further identified Ganoderic Acid C1 (GAC1) as a key ASHMI active compound in vitro. The objective of this study is to investigate GAC1 effect on neutrophil-dominant, steroid-resistant asthma in a murine model.

Methods

In this study, Balb/c mice were systematically sensitized with ragweed (RW) and alum and intranasally challenged with ragweed. Unsensitized/PBS challenged mice served as normal controls. Post sensitization, mice were given 4 weeks of oral treatment with GAC1 or acute dexamethasone (Dex) treatment at 48 hours prior to challenge. Pulmonary cytokines were measured by ELISA, and lung sections were processed for histology by H&E staining. Furthermore, GAC1 effect on MUC5AC expression and on reactive oxygen species (ROS) production in human lung epithelial cell line (NCI-H292) was determined by qRT-PCR and ROS assay kit, respectively. Computational analysis was applied to select potential targets of GAC1 in steroid-resistant neutrophil-dominant asthma. Molecular docking was performed to predict binding modes between GAC1 and Dex with TNF-α.

Results

The result of the study showed that chronic GAC1 treatment, significantly reduced pulmonary inflammation (P < 0.01-0.001 vs Sham) and airway neutrophilia (P < 0.01 vs Sham), inhibited TNF-α, IL-4 and IL-5 levels (P < 0.05-0.001 vs Sham). Acute Dex treatment reduced eosinophilic inflammation and IL-4, IL-5 levels, but had no effect on neutrophilia and TNF-α production. GAC1 treated H292 cells showed decreased MUC5AC gene expression and production of ROS (P < 0.001 vs stimulated/untreated cells). Molecular docking results showed binding energy of complex GAC1-TNF was -10.8 kcal/mol.

Discussion

GAC1 may be a promising anti-asthma botanical drug for treatment of steroid-resistant asthma.

Rhinovirus induces airway remodeling: what are the physiological consequences?

BACKGROUND

Rhinovirus infections commonly evoke asthma exacerbations in children and adults. Recurrent asthma exacerbations are associated with injury-repair responses in the airways that collectively contribute to airway remodeling. The physiological consequences of airway remodeling can manifest as irreversible airway obstruction and diminished responsiveness to bronchodilators. Structural cells of the airway, including epithelial cells, smooth muscle, fibroblasts, myofibroblasts, and adjacent lung vascular endothelial cells represent an understudied and emerging source of cellular and extracellular soluble mediators and matrix components that contribute to airway remodeling in a rhinovirus-evoked inflammatory environment.

MAIN BODY

While mechanistic pathways associated with rhinovirus-induced airway remodeling are still not fully characterized, infected airway epithelial cells robustly produce type 2 cytokines and chemokines, as well as pro-angiogenic and fibroblast activating factors that act in a paracrine manner on neighboring airway cells to stimulate remodeling responses. Morphological transformation of structural cells in response to rhinovirus promotes remodeling phenotypes including induction of mucus hypersecretion, epithelial-to-mesenchymal transition, and fibroblast-to-myofibroblast transdifferentiation. Rhinovirus exposure elicits airway hyperresponsiveness contributing to irreversible airway obstruction. This obstruction can occur as a consequence of sub-epithelial thickening mediated by smooth muscle migration and myofibroblast activity, or through independent mechanisms mediated by modulation of the β2 agonist receptor activation and its responsiveness to bronchodilators. Differential cellular responses emerge in response to rhinovirus infection that predispose asthmatic individuals to persistent signatures of airway remodeling, including exaggerated type 2 inflammation, enhanced extracellular matrix deposition, and robust production of pro-angiogenic mediators.

CONCLUSIONS

Few therapies address symptoms of rhinovirus-induced airway remodeling, though understanding the contribution of structural cells to these processes may elucidate future translational targets to alleviate symptoms of rhinovirus-induced exacerbations.

Bergapten ameliorates combined allergic rhinitis and asthma syndrome after PM2.5 exposure by balancing Treg/Th17 expression and suppressing STAT3 and MAPK activation in a mouse model

Combined allergic rhinitis and asthma syndrome (CARAS) causes chronic respiratory inflammation in allergic individuals. Long-term exposure to particulate matter 2.5 (PM2.5; particles 2.5 µm or less in diameter) can aggravate respiratory damage. Bergapten (5-methoxysporalen) is a furocoumarin mostly found in bergamot essential oil and has significant antioxidant, anticancer, and anti-inflammatory activity. This study created a model in which CARAS was exacerbated by PM2.5 exposure, in BALB/c mice and explored the potential of bergapten as a therapeutic agent. The bergapten medication increased ovalbumin (OVA)-specific immunoglobulin (Ig) G2a level in serum and decreased OVA-specific IgE and IgG1 expression. Clinical nasal symptoms diminished significantly, with weakened inflammatory reaction in both the nasal mucosa and lungs. Furthermore, bergapten controlled the T helper (Th)1 to Th2 ratio by increasing cytokines associated with Th1-like interleukin (IL)-12 and interferon gamma and decreasing the Th2 cytokines IL-4, IL-5, and IL-13. Factors closely related to the balance between regulatory T cells and Th17 (such as IL-10, IL-17, Forkhead box protein P3, and retinoic-related orphan receptor gamma) were also regulated. Notably, pro-inflammatory cytokines IL-6, IL-1β, and tumor necrosis factor-alpha were reduced by bergapten, which suppressed the activation of both the signal transducer and activator of transcription 3 signaling pathway and the mitogen-activated protein kinase signaling pathway. Therefore, bergapten might have potential as a therapeutic agent for CARAS.

Self-Reported Insufficient Sleep Is Associated With Clinical and Inflammatory Features of Asthma: A Prospective Cohort Study

BACKGROUND

A few studies have explored the association between short sleep duration and worse asthma outcomes in patients with self-reported asthma; however, all of them were cross-sectional.

OBJECTIVES

To investigate the association between self-reported sleep duration and asthma-related clinical and inflammatory characteristics and whether sleep duration is associated with asthma exacerbations (AEs) in the following year.

METHODS

A prospective cohort study consecutively recruited participants with asthma, who were classified into short (n = 58), normal (n = 380), and long (n = 84) sleep duration groups. We investigated the clinical and inflammatory characteristics and exacerbations within a 1-year follow-up.

RESULTS

Patients with short sleep duration were older and had significantly lower total IgE and FeNO levels and higher airway inflammation, characterized by increased levels of IL-6 and TNF-α in sputum than those of patients with normal sleep duration. Furthermore, they had a significantly increased risk for poorly controlled asthma (adjusted odds ratio = 2.741; 95% CI, 1.379-5.447; P = .004) and moderate to severe AEs (adjusted incidence rate ratio = 1.798; 95% CI, 1.098-2.942; P = .020).

CONCLUSIONS

Short sleep duration was associated with non-type 2 inflammation and is an independent risk factor for future AEs. Therefore, as a potentially treatable trait, sleep duration may have clinical implications for asthma management.

COVID-19 Pandemic: What Considerations Should Be Taken during the Assessment and Management of COPD Exacerbation?

The on-going coronavirus disease 2019 (COVID-19) pandemic could contribute to higher mortality in population with underlying respiratory diseases, including chronic obstructive pulmonary disease (COPD). The aim of this review was to inform readers pertaining to the correlation of COPD exacerbation and severe acute respiratory syndrome-2 (SARS-CoV-2) infection along with considerations that could be taken in the clinical diagnosis and management. The literature search was conducted on Google Scholar, Scopus, and PubMed databases using related terms (such as, but not limited to, “COVID-19,” “SARS-CoV-2,” “COPD management,” “N-acetylcysteine,” and “corticosteroids”) on November 1–9, 2021. Recent studies suggest that COVID-19 and COPD are correlated through three pathways, namely, angiotensin-converting enzyme 2 expression, dysregulation of biological parameters, and occurrence of pneumonia. Early detection of COVID-19 in patients with underlying COPD is difficult because they share similar symptoms, attributed to advanced progression of the infection and subsequently deteriorates lung function. During COPD management, clinicians are expected to take consideration on the effect of systemic corticosteroids if patients develop COVID-19. In conclusion, COVID-19 and COPD and its management are potentially correlated, contributing to the worsening of the disease. There is a need of immediate research to reveal the true correlation between COVID-19 and COPD to improve the management.

Are Patients with Asthma and Chronic Obstructive Pulmonary Disease Preferred Targets of COVID-19?

The coronavirus pandemic, known as coronavirus disease 2019 (COVID-19), is an infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus first identified in patients from Wuhan, China. Since December 2019, SARS-CoV-2 has spread swiftly around the world, infected more than 25 million people, and caused more than 800,000 deaths in 188 countries. Chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD) appear to be risk factors for COVID-19, however, their prevalence remains controversial. In fact, studies in China reported lower rates of chronic respiratory conditions in patients with COVID-19 than in the general population, while the trend is reversed in the United States and Europe. Although the underlying molecular mechanisms of a possible interaction between COVID-19 and chronic respiratory diseases remain unknown, some observations can help to elucidate them. Indeed, physiological changes, immune response, or medications used against SARS-CoV-2 may have a greater impact on patients with chronic respiratory conditions already debilitated by chronic inflammation, dyspnea, and the use of immunosuppressant drugs like corticosteroids. In this review, we discuss importance and the impact of COVID-19 on asthma and COPD patients, the possible available treatments, and patient management during the pandemic.

Lipopolysaccharide induces steroid-resistant exacerbations in a mouse model of allergic airway disease collectively through IL-13 and pulmonary macrophage activation

BACKGROUND

Acute exacerbations of asthma represent a major burden of disease and are often caused by respiratory infections. Viral infections are recognized as significant triggers of exacerbations; however, less is understood about the how microbial bioproducts such as the endotoxin (lipopolysaccharide (LPS)) trigger episodes. Indeed, increased levels of LPS have been linked to asthma onset, severity and steroid resistance.

OBJECTIVE

The goal of this study was to identify mechanisms underlying bacterial-induced exacerbations by employing LPS as a surrogate for infection.

METHODS

We developed a mouse model of LPS-induced exacerbation on the background of pre-existing type-2 allergic airway disease (AAD).

RESULTS

LPS-induced exacerbation was characterized by steroid-resistant airway hyperresponsiveness (AHR) and an exaggerated inflammatory response distinguished by increased numbers of infiltrating neutrophils/macrophages and elevated production of lung inflammatory cytokines, including TNFα, IFNγ, IL-27 and MCP-1. Expression of the type-2 associated inflammatory factors such as IL-5 and IL-13 were elevated in AAD but not altered by LPS exposure. Furthermore, AHR and airway inflammation were no longer suppressed by corticosteroid (dexamethasone) treatment after LPS exposure. Depletion of pulmonary macrophages by administration of 2-chloroadenosine into the lungs suppressed AHR and reduced IL-13, TNFα and IFNγ expression. Blocking IL-13 function, through either IL-13-deficiency or administration of specific blocking antibodies, also suppressed AHR and airway inflammation.

CONCLUSIONS & CLINICAL RELEVANCE

We present evidence that IL-13 and innate immune pathways (in particular pulmonary macrophages) contribute to LPS-induced exacerbation of pre-existing AAD and provide insight into the complex molecular processes potentially underlying microbial-induced exacerbations.

Influence of viral infection on the relationships between airway cytokines and lung function in asthmatic children

BACKGROUND

Few longitudinal studies examine inflammation and lung function in asthma. We sought to determine the cytokines that reduce airflow, and the influence of respiratory viral infections on these relationships.

METHODS

Children underwent home collections of nasal lavage during scheduled surveillance periods and self-reported respiratory illnesses. We studied 53 children for one year, analyzing 392 surveillance samples and 203 samples from 85 respiratory illnesses. Generalized estimated equations were used to evaluate associations between nasal lavage biomarkers (7 mRNAs, 10 proteins), lung function and viral infection.

RESULTS

As anticipated, viral infection was associated with increased cytokines and reduced FVC and FEV1. However, we found frequent and strong interactions between biomarkers and virus on lung function. For example, in the absence of viral infection, CXCL10 mRNA, MDA5 mRNA, CXCL10, IL-4, IL-13, CCL4, CCL5, CCL20 and CCL24 were negatively associated with FVC. In contrast, during infection, the opposite relationship was frequently found, with IL-4, IL-13, CCL5, CCL20 and CCL24 levels associated with less severe reductions in both FVC and FEV1.

CONCLUSIONS

In asthmatic children, airflow obstruction is driven by specific pro-inflammatory cytokines. In the absence of viral infection, higher cytokine levels are associated with decreasing lung function. However, with infection, there is a reversal in this relationship, with cytokine abundance associated with reduced lung function decline. While nasal samples may not reflect lower airway responses, these data suggest that some aspects of the inflammatory response may be protective against viral infection. This study may have ramifications for the treatment of viral-induced asthma exacerbations.

Predictive effect of exhaled NO and VEGF expression levels on the severity of bronchial asthma and airway inflammation

OBJECTIVE

To investigate the relationship between exhaled NO and vascular endothelial growth factor (VEGF) expression in bronchial asthma patients with asthma severity and airway inflammation.

METHODS

From January 2015 to December 2017, 260 patients with bronchial asthma diagnosed in our hospital were enrolled. The expression of VEGF in the induced sputum was measured by enzyme-linked immunosorbent assay (ELISA) in the control (n=260) and asthma groups (n=260) in the same period. The NO concentration was measured on the same day.

RESULTS

Intercellular adhesion molecule-1 (ICAM-1), VEGF, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were significantly elevated in sputum of patients with acute asthma, and the concentration in exhaled NO of all patients was also significantly higher than the control group and the stable phase of asthma. The expression of ICAM-1, VEGF, TNF-α and IL-6 was significantly elevated in patients with severe asthma. There were significant differences in patients with mild to moderate asthma (P<0.05). Correlation analysis showed that VEGF, IL-6 and TNF-α were positively correlated with the degree of asthma (P<0.05), but negatively correlated with FEV1.0, FEV1.0/FVC% and PEF (P<0.05).

CONCLUSION

The expression of VEGF in sputum in patients with bronchial asthma is closely related to the severity of asthma and airway inflammation.

Identification of IFN-γ and IL-27 as Critical Regulators of Respiratory Syncytial Virus-Induced Exacerbation of Allergic Airways Disease in a Mouse Model

Respiratory syncytial virus (RSV) infection induces asthma exacerbations, which leads to worsening of clinical symptoms and may result in a sustained decline in lung function. Exacerbations are the main cause of morbidity and mortality associated with asthma, and significantly contribute to asthma-associated healthcare costs. Although glucocorticoids are used to manage exacerbations, some patients respond to them poorly. The underlying mechanisms associated with steroid-resistant exacerbations remain largely unknown. We have previously established a mouse model of RSV-induced exacerbation of allergic airways disease, which mimics hallmark clinical features of asthma. In this study, we have identified key roles for macrophage IFN-γ and IL-27 in the regulation of RSV-induced exacerbation of allergic airways disease. Production of IFN-γ and IL-27 was steroid-resistant, and neutralization of IFN-γ or IL-27 significantly suppressed RSV-induced steroid-resistant airway hyperresponsiveness and airway inflammation. We have previously implicated activation of pulmonary macrophage by TNF-α and/or MCP-1 in the mechanisms of RSV-induced exacerbation. Stimulation of pulmonary macrophages with TNF-α and/or MCP-1 induced expression of both IFN-γ and IL-27. Our findings highlight critical roles for IFN-γ and IL-27, downstream of TNF-α and MCP-1, in the mechanism of RSV-induced exacerbation. Thus, targeting the pathways that these factors activate may be a potential therapeutic approach for virus-induced asthma exacerbations.

The Influence of Asthma and/or Hay Fever on Pregnancy: Data from the 1995 National Survey of Family Growth

BACKGROUND

Asthma is associated with adverse pregnancy outcomes. At the same time there is a worldwide increase in asthma and hay fever.

OBJECTIVE

This study addresses whether asthma and/or hay fever adversely influence pregnancy outcomes.

METHODS

Data from the 1995 National Survey of Family Growth that include a history of diagnosed asthma, hay fever, and adverse pregnancy outcomes in 10,847 women representative of the US population aged 15 to 44 years were analyzed.

RESULTS

Women with the allergic phenotypes asthma and hay fever and hay fever only had no significant increase in adverse pregnancy outcomes (spontaneous pregnancy loss, preterm birth, infant low birth weight), whereas women with the nonatopic phenotype asthma only (without hay fever) did. The study did not evaluate endotypes.

CONCLUSIONS

This study provides new data that the allergic phenotypes, asthma and hay fever and hay fever only, are compatible with healthy pregnancy, whereas the nonatopic asthma phenotype, asthma only, adversely impacts pregnancy.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Serum IFN-γ-induced protein 10 (IP-10) as a biomarker for severity of acute respiratory infection in healthy adults

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Serum IP-10 concentrations from 225 ARI episodes correlated with ARI severity for the episode.

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IP-10 concentrations varied with the viral pathogen that was identified.

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IP-10 may be a biomarker for ARI severity and for presence of a viral pathogen.

Background

The inflammatory chemokine, interferon-gamma inducible protein of 10 kDa (IP-10), is a biomarker associated with several conditions.

Objectives

This study investigated serum concentrations of IP-10 in healthy individuals who developed acute respiratory infection (ARI). The hypothesis is that serum IP-10 concentrations correlate with ARI severity and detection of viral pathogens.

Study design

Data come from a randomized controlled trial measuring the effects of mindfulness meditation or exercise on ARI (Clinical Trials ID: NCT01654289). Healthy adults ages 30–69 were followed for a single season for ARI incidence and severity. This trial is ongoing, and the investigators are still blinded. When a participant reported ARI symptoms, nasal swab and lavage for PCR-based viral identification and blood samples were collected within the first 72 h of ARI symptoms. Serum IP-10 concentrations were measured by ELISA (R&D Systems, Inc., Quantikine ELISA, Minneapolis, MN). ARI severity was measured using the validated Wisconsin Upper Respiratory Symptom Survey (WURSS-24) until the ARI episode resolved.

Results

Serum IP-10 concentrations from 225 ARI episodes correlated with ARI global severity (rho 0.28 [95% CI: 0.15–0.39]; p < 0.001). IP-10 concentrations were higher with an ARI in which a viral pathogen was detected compared to no viral pathogen detected (median 366 pg/ml [IQR: 227–486] vs 163 pg/ml [IQR: 127–295], p < 0.0001). Influenza infections had higher IP-10 concentrations than coronavirus, enterovirus or rhinovirus, and paramyxovirus.

Conclusion

Serum IP-10 concentration correlates with ARI global severity. Also, IP-10 concentration measured early in the course of the ARI correlates with the daily severity, duration, and illness symptoms.

Interactions of Respiratory Viruses and the Nasal Microbiota during the First Year of Life in Healthy Infants

Respiratory viral infections are very frequent in infancy and of importance in acute and chronic disease development. Infections with human rhinovirus (HRV) are, e.g., associated with the later development of asthma. We found that only symptomatic HRV infections were associated with acute changes in the nasal microbiota, mainly characterized by a loss of microbial diversity. Infants with more frequent symptomatic HRV infections had a lower bacterial diversity at the end of the first year of life. Whether the interaction between viruses and the microbiota is one pathway contributing to asthma development will be assessed in the follow-ups of these children. Independent of that, measurements of microbial diversity might represent a potential marker for risk of later lung disease or monitoring of early life interventions.

Traditional culture techniques have shown that increased bacterial colonization is associated with viral colonization; however, the influence of viral colonization on the whole microbiota composition is less clear. We thus aimed to understand the interaction of viral infections and the nasal microbiota in early life to appraise their roles in disease development. Thirty-two healthy, unselected infants were included in this prospective longitudinal cohort study within the first year of life. Biweekly nasal swabs (n = 559) were taken, and the microbiota was analyzed by 16S rRNA pyrosequencing, and 10 different viruses and 2 atypical bacteria were characterized by real-time PCR (combination of seven duplex samples). In contrast to asymptomatic human rhinovirus (HRV) colonization, symptomatic HRV infections were associated with lower alpha diversity (Shannon diversity index [SDI]), higher bacterial density (PCR concentration), and a difference in beta diversities (Jaccard and Bray-Curtis index) of the microbiota. In addition, infants with more frequent HRV infections had a lower SDI at the end of the study period. Overall, changes in the microbiota associated with symptomatic HRV infections were characterized by a loss of microbial diversity. The interaction between HRV infections and the nasal microbiota in early life might be of importance for later disease development and indicate a potential approach for future interventions.

IMPORTANCE Respiratory viral infections are very frequent in infancy and of importance in acute and chronic disease development. Infections with human rhinovirus (HRV) are, e.g., associated with the later development of asthma. We found that only symptomatic HRV infections were associated with acute changes in the nasal microbiota, mainly characterized by a loss of microbial diversity. Infants with more frequent symptomatic HRV infections had a lower bacterial diversity at the end of the first year of life. Whether the interaction between viruses and the microbiota is one pathway contributing to asthma development will be assessed in the follow-ups of these children. Independent of that, measurements of microbial diversity might represent a potential marker for risk of later lung disease or monitoring of early life interventions.

1,25-Dihydroxyvitamin D3 targeting VEGF pathway alleviates house dust mite (HDM)-induced airway epithelial barrier dysfunction

BACKGROUND

In our previous studies, we have indentified that 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) can alleviate toluene diisocyanate-induced airway epithelial barrier disruption and we also found that vascular endothelial growth factor (VEGF) derived from airway epithelials cells could disrupt epithelial barrier.

OBJECTIVE

The study aimed to investigate whether 1,25(OH)₂D₃ can inhibit house dust mite (HDM) induced airway epithelial barrier dysfunction by regulating the VEGF pathway.

METHOD

The 16HBE and BEAS-2B cells were cultured and treated according to the experiment requirement. Trans Epithelial Electric Resistance (TEER), permeability of epithelial layer, and distribution and expression of junction proteins were used to evaluate the cell layer barrier function, Western Blot was used to evaluate the expression of junction proteins and phosphorylated Akt in the cells, RT-PCR and ELISA were used to evaluate the VEGF gene expression and protein release in the cells. Recombinant VEGF165 was used to determine the role of the VEGF pathway in the epithelial barrier function.

RESULTS

HDM resulted in a decline in TEER and increase of cell permeability, following abnormal distribution and expression of junction proteins (E-Cadherin and zona occludens (ZO)-1), accompanied by a significant upregulation of VEGF and phosphorylated Akt, which were all partly recovered by treatment with either 1,25(OH)₂D₃ or PI3K inhibitor LY294002. VEGF165-induced barrier dysfunction was accompanied by disruption of the epithelial E-cadherin and β-catenin, pretreatment of 1,25(OH)₂D₃ and LY294002 markedly attenuated VEGF-induced airway barrier disruption in 16HBE cells.

CONCLUSION

1,25(OH)₂D₃ can alleviate HDM-induced airway epithelial barrier dysfunction by inhibiting PI3K pathway-dependent VEGF release.

Bromodomain and Extra Terminal (BET) Inhibitor Suppresses Macrophage-Driven Steroid-Resistant Exacerbations of Airway Hyper-Responsiveness and Inflammation

BACKGROUND

Exacerbations of asthma are linked to significant decline in lung function and are often poorly controlled by corticosteroid treatment. Clinical investigations indicate that viral and bacterial infections play crucial roles in the onset of steroid-resistant inflammation and airways hyperresponsiveness (AHR) that are hallmark features of exacerbations. We have previously shown that interferon γ (IFNγ) and lipopolysaccharide (LPS) cooperatively activate pulmonary macrophages and induce steroid-resistant airway inflammation and AHR in mouse models. Furthermore, we have established a mouse model of respiratory syncytial virus (RSV)-induced exacerbation of asthma, which exhibits macrophage-dependent, steroid-resistant lung disease. Emerging evidence has demonstrated a key role for bromo- and extra-terminal (BET) proteins in the regulation of inflammatory gene expression in macrophages. We hypothesised that BET proteins may be involved in the regulation of AHR and airway inflammation in our steroid-resistant exacerbation models.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the effects of a BET inhibitor (I-BET-762) on the development of steroid-resistant AHR and airway inflammation in two mouse models. I-BET-762 administration decreased macrophage and neutrophil infiltration into the airways, and suppressed key inflammatory cytokines in both models. I-BET treatment also suppressed key inflammatory cytokines linked to the development of steroid-resistant inflammation such as monocyte chemoattractant protein 1 (MCP-1), keratinocyte-derived protein chemokine (KC), IFNγ, and interleukin 27 (IL-27). Attenuation of inflammation was associated with suppression of AHR.

CONCLUSIONS/SIGNIFICANCE

Our results suggest that BET proteins play an important role in the regulation of steroid-resistant exacerbations of airway inflammation and AHR. BET proteins may be potential targets for the development of future therapies to treat steroid-resistant inflammatory components of asthma.

Developments in the field of allergy in 2014 through the eyes of Clinical and Experimental Allergy

The pathogenesis of asthma continues to be a major topic of interest to our authors with reviews and original papers on the role of viruses, mechanisms of inflammation, biomarkers, and phenotypes of asthma being major topics. A number of papers described new treatments for asthma focusing on blocking the Th2 response reflecting the fact that two decades of work in this area is finally bearing fruit. The pathogenesis of chronic rhinosinusitis is a growing area of interest, but there has been less on the genetics of airways disease than in previous years possibly reflecting the degree of rigour (and therefore a smaller body of work), with which these sorts of studies are now being undertaken. There continues to be a wide range of papers dealing with mechanisms of allergic disease ranging from clinical-based studies to basic research and the use of in vivo animal models especially mice. As before, mechanisms and new approaches to immunotherapy are common themes. Several were published in the allergens section investigating modification of allergens to increase their effectiveness and reduce the risk of adverse events. Risk factors for allergic disease was a common theme in the epidemiology section and food allergy a common theme in clinical allergy with papers on the development of protocols to induce tolerance and attempts to find biomarkers to distinguish sensitization from allergic disease. This was another exciting year for the editors, and we hope the readers of the journal.

TNF-α and Macrophages Are Critical for Respiratory Syncytial Virus-Induced Exacerbations in a Mouse Model of Allergic Airways Disease

Viral respiratory infections trigger severe exacerbations of asthma, worsen disease symptoms, and impair lung function. To investigate the mechanisms underlying viral exacerbation, we established a mouse model of respiratory syncytial virus (RSV)-induced exacerbation after allergen sensitization and challenge. RSV infection of OVA-sensitized/challenged BALB/c mice resulted in significantly increased airway hyperresponsiveness (AHR) and macrophage and neutrophil lung infiltration. Exacerbation was accompanied by increased levels of inflammatory cytokines (including TNF-α, MCP-1, and keratinocyte-derived protein chemokine [KC]) compared with uninfected OVA-treated mice or OVA-treated mice exposed to UV-inactivated RSV. Dexamethasone treatment completely inhibited all features of allergic disease, including AHR and eosinophil infiltration, in uninfected OVA-sensitized/challenged mice. Conversely, dexamethasone treatment following RSV-induced exacerbation only partially suppressed AHR and failed to dampen macrophage and neutrophil infiltration or inflammatory cytokine production (TNF-α, MCP-1, and KC). This mimics clinical observations in patients with exacerbations, which is associated with increased neutrophils and often poorly responds to corticosteroid therapy. Interestingly, we also observed increased TNF-α levels in sputum samples from patients with neutrophilic asthma. Although RSV-induced exacerbation was resistant to steroid treatment, inhibition of TNF-α and MCP-1 function or depletion of macrophages suppressed features of disease, including AHR and macrophage and neutrophil infiltration. Our findings highlight critical roles for macrophages and inflammatory cytokines (including TNF-α and MCP-1) in viral-induced exacerbation of asthma and suggest examination of these pathways as novel therapeutic approaches for disease management.

Challenges and Current Efforts in the Development of Biomarkers for Chronic Inflammatory and Remodeling Conditions of the Lungs

This review discusses biomarkers that are being researched for their usefulness to phenotype chronic inflammatory lung diseases that cause remodeling of the lung's architecture. The review focuses on asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension. Bio-markers of environmental exposure and specific classes of biomarkers (noncoding RNA, metabolism, vitamin, coagulation, and microbiome related) are also discussed. Examples of biomarkers that are in clinical use, biomarkers that are under development, and biomarkers that are still in the research phase are discussed. We chose to present examples of the research in biomarker development by diseases, because asthma, COPD, and pulmonary hypertension are distinct entities, although they clearly share processes of inflammation and remodeling.

Noninvasive effects measurements for air pollution human studies: methods, analysis, and implications

Human exposure studies, compared with cell and animal models, are heavily relied upon to study the associations between health effects in humans and air pollutant inhalation. Human studies vary in exposure methodology, with some work conducted in controlled settings, whereas other studies are conducted in ambient environments. Human studies can also vary in the health metrics explored, as there exists a myriad of health effect end points commonly measured. In this review, we compiled mini reviews of the most commonly used noninvasive health effect end points that are suitable for panel studies of air pollution, broken into cardiovascular end points, respiratory end points, and biomarkers of effect from biological specimens. Pertinent information regarding each health end point and the suggested methods for mobile collection in the field are assessed. In addition, the clinical implications for each health end point are summarized, along with the factors identified that can modify each measurement. Finally, the important research findings regarding each health end point and air pollutant exposures were reviewed. It appeared that most of the adverse health effects end points explored were found to positively correlate with pollutant levels, although differences in study design, pollutants measured, and study population were found to influence the magnitude of these effects. Thus, this review is intended to act as a guide for researchers interested in conducting human exposure studies of air pollutants while in the field, although there can be a wider application for using these end points in many epidemiological study designs.