Restoration of the normal Clara cell phenotype after chronic allergic inflammation

Cyp2e1 protects against OVA-induced allergic rhinitis through the inhibition of Th2 cell activation and differentiation: Mediated by MAFB

Allergic rhinitis (AR) is a common allergic disease. Cytochrome P450, family 2, subfamily e, polypeptide 1 (Cyp2e1) is a member of the cytochrome P450 family of enzymes, while its role in AR is still unveiled. In AR mice, T cell-specific overexpression of Cyp2e1 relieved the AR symptoms. Overexpressed-Cyp2e1 restrained the infiltration of eosinophils and mast cells in the nasal mucosa of mice, and the inflammatory cells in nasal lavage fluid (NALF). Cyp2e1 overexpressed mice exhibited decreased goblet cell hyperplasia and mucus secretion as well as decreased MUC5AC expression in nasal mucosa. The epithelial permeability and integrity of nasal mucosa were improved upon Cyp2e1 overexpression in AR mice, as evidenced by decreased fluorescein isothiocyanate-dextran 4 content in serum, increased expression of IL-25, IL-33, and TSLP in NALF, and increased expression of ZO-1 and occluding in nasal mucosa. Cyp2e1 inhibited Th2 immune response by decreasing the expression and secretion of IL-4, IL-5, and IL-13 as well as the expression of GATA-3 in NALF or nasal mucosa. We proved that Cyp2e1 inhibited the differentiation of naïve CD4+ T cells toward the Th2 subtype, which was regulated by MAFB by binding to Cyp2e1 promoter to activate its transcription. Overall, these results show the potential role of Cyp2e1 in alleviating AR symptoms by restraining CD4+ T cells to Th2 cell differentiation. Our findings provide further insight into the AR mechanism.

Association of serum CC16 levels with eosinophilic inflammation and respiratory dysfunction in severe asthma

BACKGROUND

There are knowledge gaps in the potential role of Club cell 16-kDa secretory protein (CC16) in severe asthma phenotypes and type 2 inflammation, as well as the longitudinal effect of CC16 on pulmonary function tests and exacerbation risk in epidemiological studies.

OBJECTIVE AND METHODS

To assess whether serum CC16 is associated with eosinophilic inflammation in patients with severe asthma. We also examined the effect of this protein on the annual decline in forced expiratory volume in the first second (FEV₁) and the risk of exacerbation using a longitudinal approach. We recruited 127 patients with severe asthma from 30 hospitals/pulmonary clinics in Hokkaido, Japan. The least square means and standard error were calculated for T-helper 2 (Th2) biomarkers and pulmonary function test across CC16 tertiles at baseline. We did the same for asthma exacerbation and annual decline in FEV₁ with 3 and 5 years' follow-up, respectively.

RESULTS

We found that serum CC16 was inversely associated with sputum eosinophils and blood periostin in a dose-response manner. Baseline CC16 and FEV₁/forced vital capacity ratio were positively associated in adjusted models (p for trend = 0.008). Patients with the lowest tertile of serum CC16 levels at baseline had a -14.3 mL decline in FEV₁ than those with the highest tertile over 5 years of follow-up (p for trend = 0.031, fully adjusted model). We did not find any association of CC16 with exacerbation risk.

CONCLUSION

Patients with severe asthma with lower circulatory CC16 had enhanced eosinophilic inflammation with rapid FEV₁ decline over time.

Radiation-activated secretory proteins of Scgb1a1+ club cells increase the efficacy of immune checkpoint blockade in lung cancer

Radiation therapy (RT) in combination with immune checkpoint inhibitor (ICI) represents a promising regimen for non-small cell lung cancer (NSCLC), however, the underlying mechanisms are poorly characterized. We identified a specific dose of RT that conferred tumor regression and improved survival in NSCLC models when combined with ICI. The immune-modulating functions of RT was ascribed to activated lung-resident Scgb1a1+ club cells. Importantly, mice with club cell-specific knockout of synaptosome-associated protein 23 failed to benefit from the combination treatment, indicating a pivotal role of club cell secretome. We identified 8 club cells secretory proteins, which inhibited immunosuppressive myeloid cells, reduced pro-tumor inflammation, and enhanced anti-tumor immunity. Notably, CC10, a member of club cell secretome was increased in plasma of NSCLC patients responding to the combination therapy. By revealing an immune-regulatory role of club cells, our studies have the potential to guide future clinical trials of ICI in NSCLC.

Single and joint effects of chronic exposure to chlorpyrifos and glyphosate based pesticides on structural biomarkers in Cnesterodon decemmaculatus

Worldwide freshwater bodies that cross agricultural or urban areas are exposed to mixtures of xenobiotics. In particular, pesticides are usually part of these mixtures and could come into direct or indirect contact with biota and therefore, organisms have to cope with this altered scenario and the detrimental effects of these substances. Commercial formulations of chlorpyrifos and glyphosate, and their mixtures were evaluated using a set of biomarkers in the native fish C. decemmaculatus exposed to relevant environmentally pesticides concentrations. The biomarkers measured were: histopathological indices and tissue ultrastructure in liver and nuclear abnormalities and micronuclei in erythrocytes. During 42 days adult females were exposed to the following concentrations of Clorfox and Roundup Max (chlorpyrifos and glyphosate, respectively): 0.84 nl/l and 8.4 nl/l of Clorfox (CF), 0.2 and 2 mg/l of Roundup Max (RM) and all the combinations of these concentrations. Being the low concentrations of both pesticides environmentally relevant. Nuclear abnormalities of erythrocytes were registered under CF, RM and only one mixture. Histological inflammatory alterations increased in individuals exposed to CF and two mixtures. Finally, some pesticide combinations increased the circulatory alterations in liver. Ultrastructural changes in hepatocytes were registered at all the pesticide treatments. The different biomarker responses showed in the mixtures treatments reflected complex interactions, showing the mixture of the low concentrations of both pesticides (the environmentally relevant), potentiated effects. According to our results the presence of these substances in freshwaters could impose important risks for natural populations by causing deleterious effects on the native fish species C. decemmaculatus.

Clara cell protein 16 release from the nasal mucosa in allergic rhinitis, chronic rhinosinusitis, and exposure to air pollutants

Clara cell protein 16 (CC16) is a small protein mainly produced by non-ciliated Clara cells in the respiratory epithelium. It has an anti-inflammatory role in chronic upper and lower airway eosinophilic inflammations. Decreased levels of CC16 are found in the nasal secretions and plasma of patients with chronic eosinophilic inflammatory disorders, such as asthma, allergic rhinitis, and chronic rhinosinusitis with or without nasal polyps, as well as in people exposed to high levels of air pollutants. Intranasal corticosteroid administration suppresses chronic inflammation of the nasal mucosa driven by eosinophils and stimulates local CC16 production. CC16 can be a reliable biomarker of the beneficial effects of perennial allergic rhinitis and chronic rhinosinusitis therapy and of the functional recovery of the nasal mucosa after treatment with topical glucocorticoids.

Roles of Bronchopulmonary C-fibers in airway Hyperresponsiveness and airway remodeling induced by house dust mite

Background

Asthma is characterized by chronic airway inflammation, airway hyperresponsiveness (AHR), and airway remodeling. While exposure of house dust mites (HDM) is a common cause of asthma, the pathogenesis of the HDM-induced asthma is not fully understood. Bronchopulmonary C-fibers (PCFs) contribute to the neurogenic inflammation, viral infection induced-persistent AHR, and ovalbumin induced collagen deposition largely via releasing neuropeptides, such as substance P (SP). However, PCF roles in the pathogenesis of the HDM-induced asthma remain unexplored. The goal of this study was to determine what role PCFs played in generating these characteristics.

Methods

We compared the following variables among the PCF-intact and -degenerated BALB/c mice with and without chronic HDM exposure (four groups): 1) AHR and pulmonary SP; 2) airway smooth muscle (ASM) mass; 3) pulmonary inflammatory cells; and 4) epithelium thickening and mucus secretion.

Results

We found that HDM evoked AHR associated with upregulation of pulmonary SP and inflammation, ASM mass increase, epithelium thickenings, and mucus hypersecretion. PCF degeneration decreased the HDM-induced changes in AHR, pulmonary SP and inflammation, and ASM mass, but failed to significantly affect the epithelium thickening and mucus hypersecretion.

Conclusion

Our data suggest an involvement of PCFs in the mechanisms by which HDM induces allergic asthma via airway inflammation, AHR, and airway remodeling.

Montelukast, current indications and prospective future applications

INTRODUCTION

Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions.

AREAS COVERED

Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

The role and importance of club cells (Clara cells) in the pathogenesis of some respiratory diseases

The report presents the cellular structure of the respiratory system as well as the history of club cells (Clara cells), their ultrastructure, and location in the airways and human organs. The authors discuss the biochemical structure of proteins secreted by these cells and their importance for the integrity and regeneration of the airway epithelium. Their role as progenitor cells for the airway epithelium and their involvement in the biotransformation of toxic xenobiotics introduced into the lungs during breathing is emphasized. This is followed by a discussion of the clinical aspects associated with club cells, demonstrating that tracking the serum concentration of club cell-secreted proteins is helpful in the diagnosis of a number of lung tissue diseases. Finally, suggestions are provided regarding the possible use of proteins secreted by club cells in the treatment of serious respiratory conditions.

Protective phenotypes of club cells and alveolar macrophages are favored as part of endotoxin-mediated prevention of asthma

Atopic asthma is a chronic allergic disease that involves T-helper type 2 (Th2)-inflammation and airway remodeling. Bronchiolar club cells (CC) and alveolar macrophages (AM) are sentinel cells of airway barrier against inhaled injuries, where allergy induces mucous metaplasia of CC and the alternative activation of AM, which compromise host defense mechanisms and amplify Th2-inflammation. As there is evidence that high levels of environmental endotoxin modulates asthma, the goal of this study was to evaluate if the activation of local host defenses by Lipopolysaccharide (LPS) previous to allergy development can contribute to preserving CC and AM protective phenotypes. Endotoxin stimulus before allergen exposition reduced hallmarks of allergic inflammation including eosinophil influx, Interleukin-4 and airway hyperreactivity, while the T-helper type 1 related cytokines IL-12 and Interferon-γ were enhanced. This response was accompanied by the preservation of the normal CC phenotype and the anti-allergic proteins Club Cell Secretory Protein (CCSP) and Surfactant-D, thereby leading to lower levels of CC metaplasia and preventing the increase of the pro-Th2 cytokine Thymic stromal lymphopoietin. In addition, classically activated alveolar macrophages expressing nitric oxide were promoted over the alternatively activated ones that expressed arginase-1. We verified that LPS induced a long-term overexpression of CCSP and the innate immune markers Toll-like receptor 4, and Tumor Necrosis Factor-α, changes that were preserved in spite of the allergen challenge. These results demonstrate that LPS pre-exposition modifies the local bronchioalveolar microenvironment by inducing natural anti-allergic mechanisms while reducing local factors that drive Th2 type responses, thus modulating allergic inflammation.