Role In Airway Inflammation Research Articles

Applying a polysaccharide lyase from Stenotrophomonas maltophilia to disrupt alginate exopolysaccharide produced by Pseudomonas aeruginosa clinical isolates.

Pseudomonas aeruginosa is a major opportunistic human pathogen in part due to its ability to synthesize biofilms that confer antibiotic resistance. Biofilm is a mixture of polysaccharides, DNA, and proteins that encapsulate cells, protecting them from antibiotics, disinfectants, and other cleaning agents. Due to its ability to increase antibiotic and immune resistance, the exopolysaccharide alginate plays a large role in airway inflammation and chronic P. aeruginosa infection. As a result, colonization with P. aeruginosa is the leading cause of morbidity and mortality in CF patients. Thus, it is an obvious target to improve the treatment regimen for P. aeruginosa infection. In this study, we demonstrate that polysaccharide lyase, Smlt1473, inhibits alginate secretion and degrades established alginate from a variety of mucoid P. aeruginosa clinical isolates. Additionally, Smlt1473 differs from other alginate lyases in that it is active against acetylated alginate, which is secreted during chronic lung infection. These results suggest that Smlt1473 may be useful in treating infections associated with alginate-producing P. aeruginosa, as well as have the potential to reduce P. aeruginosa EPS in non-clinical settings.

Emotion regulation among adults with asthma: Links with short-acting inhaler medication overuse and utilization of acute medical care

Objective Existing research suggests that emotion plays an important role in airway inflammation and asthma symptom control. The objective of this study was to determine whether difficulties regulating emotion were associated with overuse of short-acting inhaled medications and acute medical care usage in adults with asthma. Methods The sample included 401 adults with asthma recruited from an online panel of adults with chronic respiratory disease. Sequential binary logistic regression models were used to examine the associations of emotion regulation with short-acting inhaled medication use and acute medical care use, controlling for patient characteristics and comorbid mental health conditions. Results Greater difficulties with emotion regulation were significantly associated with greater odds of short-acting inhaler medication overuse (p < 0.001), emergency department visits (p < 0.001), and hospitalizations (p = 0.001). Conclusions Emotion dysregulation may play an important role in asthma management. Evidence-based interventions to reduce difficulties in emotion regulation may help improve problematic patterns of short-acting medication overuse and acute service use. The current findings should be interpreted in the context of several limitations, including the use of self-report measures. Future research should use electronic medical records or metered dose inhalers to objectively assess short-acting inhaler overuse and acute medical care use.

PIP-seq identifies novel heterogeneous lung innate lymphocyte population activation after combustion product exposure

Innate lymphoid cells (ILCs) are a heterogeneous population that play diverse roles in airway inflammation after exposure to allergens and infections. However, how ILCs respond after exposure to environmental toxins is not well understood. Here we show a novel method for studying the heterogeneity of rare lung ILC populations by magnetic enrichment for lung ILCs followed by particle-templated instant partition sequencing (PIP-seq). Using this method, we were able to identify novel group 1 and group 2 ILC subsets that exist after exposure to both fungal allergen and burn pit-related constituents (BPC) that include dioxin, aromatic hydrocarbon, and particulate matter. Toxin exposure in combination with fungal allergen induced activation of specific ILC1/NK and ILC2 populations as well as promoted neutrophilic lung inflammation. Oxidative stress pathways and downregulation of specific ribosomal protein genes (Rpl41 and Rps19) implicated in anti-inflammatory responses were present after BPC exposure. Increased IFNγ expression and other pro-neutrophilic mediator transcripts were increased in BPC-stimulated lung innate lymphoid cells. Further, the addition of BPC induced Hspa8 (encodes HSC70) and aryl hydrocarbon transcription factor activity across multiple lung ILC subsets. Overall, using an airway disease model that develops after occupational and environmental exposures, we demonstrate an effective method to better understand heterogenous ILC subset activation.

Extracellular Vesicles Induce Nuclear Factor-κB Activation and Interleukin-8 Synthesis through miRNA-191-5p Contributing to Inflammatory Processes: Potential Implications in the Pathogenesis of Chronic Obstructive Pulmonary Disease.

Extracellular vesicles (EVs) play a pivotal role in a variety of physiologically relevant processes, including lung inflammation. Recent attention has been directed toward EV-derived microRNAs (miRNAs), such as miR-191-5p, particularly in the context of inflammation. Here, we investigated the impact of miR-191-5p-enriched EVs on the activation of NF-κB and the expression of molecules associated with inflammation such as interleukin-8 (IL-8). To this aim, cells of bronchial epithelial origin, 16HBE, were transfected with miR-191-5p mimic and inhibitor and subsequently subjected to stimulations to generate EVs. Then, bronchial epithelial cells were exposed to the obtained EVs to evaluate the activation of NF-κB and IL-8 levels. Additionally, we conducted a preliminary investigation to analyze the expression profiles of miR-191-5p in EVs isolated from the plasma of patients diagnosed with chronic obstructive pulmonary disease (COPD). Our initial findings revealed two significant observations. First, the exposure of bronchial epithelial cells to miR-191-5p-enriched EVs activated the NF-kB signaling and increased the synthesis of IL-8. Second, we discovered the presence of miR-191-5p in peripheral blood-derived EVs from COPD patients and noted a correlation between miR-191-5p levels and inflammatory and functional parameters. Collectively, these data corroborate and further expand the proinflammatory role of EVs, with a specific emphasis on miR-191-5p as a key cargo involved in this process. Consequently, we propose a model in which miR-191-5p, carried by EVs, plays a role in airway inflammation and may contribute to the pathogenesis of COPD.

PIP-Seq identifies novel heterogeneous lung innate lymphocyte population activation after combustion product exposure.

Innate lymphoid cells (ILCs) are a heterogeneous population that play diverse roles in airway inflammation after exposure to allergens and infections. However, how ILCs respond after exposure to environmental toxins is not well understood. Here we show a novel method for studying the heterogeneity of rare lung ILC populations by magnetic enrichment for lung ILCs followed by particle-templated instant partition sequencing (PIP-seq). Using this method, we were able to identify novel group 1 and group 2 ILC subsets that exist after exposure to both fungal allergen and burn pit-related constituents (BPC) that include dioxin, aromatic hydrocarbon, and particulate matter. Toxin exposure in combination with fungal allergen induced activation of specific ILC1/NK and ILC2 populations as well as promoted neutrophilic lung inflammation. Oxidative stress pathways and downregulation of specific ribosomal protein genes ( Rpl41 and Rps19 ) implicated in anti-inflammatory responses were present after BPC exposure. Increased IFNγ expression and other pro-neutrophilic mediator transcripts were increased in BPC-stimulated lung innate lymphoid cells. Further, the addition of BPC induced Hspa8 (encodes HSC70) and aryl hydrocarbon transcription factor activity across multiple lung ILC subsets. Overall, using an airway disease model that develops after occupational and environmental exposures, we demonstrate an effective method to better understand heterogenous ILC subset activation.

IL-37 protects against house dust mite-induced airway inflammation and airway epithelial barrier dysfunction via inhibiting store-operated calcium entry

BackgroundAirway epithelial barrier dysfunction has been proved to contribute to the development of type 2 inflammation of asthma. Interleukin (IL)-37 is a negative regulator of immune responses and allergic airway inflammation. However, whether IL-37 has any effect on airway epithelial barrier has been unknown. MethodsWe evaluated the role of IL-37 in both mouse model and cultured 16HBE cells. Histology and ELISA assays were used to evaluate airway inflammation. FITC-dextran permeability assay was used to evaluate the airway epithelial barrier function. Immunofluorescence, western blot and quantitative Real-Time PCR (RT-PCR) were used to evaluate the distribution and expression of tight junction proteins. RT-PCR and Ca2+ fluorescence measurement were used to evaluate the mRNA expression and activity of store-operated calcium entry (SOCE). ResultsIL-37 inhibited house dust mite (HDM)-induced airway inflammation and decreased the levels of IgE in serum and type 2 cytokines in bronchoalveolar lavage fluid (BALF) compared to asthmatic mice. IL-37 protected against HDM-induced airway epithelial barrier dysfunction, including reduced leakage of FITC-dextran, enhanced expression of TJ proteins, and restored the membrane distribution of TJ proteins. Moreover, IL-37 decreased the level of IL-33 in the BALF of asthmatic mice and the supernatants of HDM-treated 16HBE cells. IL-37 decreased the peak level of Ca2+ fluorescence induced by thapsigargin and HDM, and inhibited the mRNA expression of Orai1, suggesting an inhibiting effect of IL-37 on SOCE in airway epithelial cells. ConclusionIL-37 plays a protective role in airway inflammation and HDM-induced airway epithelial barrier dysfunction by inhibiting SOCE.

Spleen tyrosine kinase inhibitor R406 has both antiviral and anti-inflammatory effects on severe influenza A infection.

Death due to severe influenza is usually a fatal complication of a dysregulated immune response more than the acute virulence of an infectious agent. Although spleen tyrosine kinase (SYK) as a critical immune signaling molecule and therapeutic target plays roles in airway inflammation and acute lung injury, the role of SYK in influenza virus infection is not clear. Here, we investigated the antiviral and anti-inflammatory effects of SYK inhibitor R406 on influenza infection through a coculture model of human alveolar epithelial (A549) and macrophage (THP-1) cell lines and mouse model. The results showed that R406 treatment increased the viability of A549 and decreased the pathogenicity and mortality of lethal influenza virus in mice with influenza A infection, decreased levels of intracellular signaling molecules under the condition of inflammation during influenza virus infection. Combination therapy with oseltamivir further ameliorated histopathological damage in the lungs of mice and further delayed the initial time to death compared with R406 treatment alone. This study demonstrated that phosphorylation of SYK is involved in the pathogenesis of influenza, and R406 has antiviral and anti-inflammatory effects on the treatment of the disease, which may be realized through multiple pathways, including the already reported SYK/STAT/IFNs-mediated antiviral pathway, as well as TNF-α/SYK- and SYK/Akt-based immunomodulation pathway.

The role of Neutrophil counts, infections and Smoking in mediating the Effect of Bronchiectasis on Chronic Obstructive Pulmonary Disease: a mendelian randomization study.

The causality of the relationship between bronchiectasis and chronic obstructive pulmonary disease (COPD) remains unclear. This study aims to investigate the potential causal relationship between them, with a specific focus on the role of airway inflammation, infections, smoking as the mediators in the development of COPD. We conducted a two-sample Mendelian randomization (MR) analysis to assess: (1) the causal impact of bronchiectasis on COPD, sex, smoking status, infections, eosinophil and neutrophil counts, as well as the causal impact of COPD on bronchiectasis; (2) the causal effect of smoking status, infections and neutrophil counts on COPD; and (3) the extent to which the smoking status, infections and neutrophil counts might mediate any influence of bronchiectasis on the development of COPD. COPD was associated with a higher risk of bronchiectasis (OR 1.28 [95% CI 1.05, 1.56]). Bronchiectasis was associated with a higher risk of COPD (OR 1.08 [95% CI 1.04, 1.13]), higher levels of neutrophil (OR 1.01 [95% CI 1.00, 1.01]), higher risk of respiratory infections (OR 1.04 [95% CI 1.02, 1.06]) and lower risk of smoking. The causal associations of higher neutrophil cells, respiratory infections and smoking with higher COPD risk remained after performing sensitivity analyses that considered different models of horizontal pleiotropy, with OR 1.17, 1.69 and 95.13, respectively. The bronchiectasis-COPD effect was 0.99, 0.85 and 122.79 with genetic adjustment for neutrophils, respiratory infections and smoking. COPD and bronchiectasis are mutually causal. And increased neutrophil cell count and respiratory infections appears to mediate much of the effect of bronchiectasis on COPD.

TSLP is localized in and released from human lung macrophages activated by T2-high and T2-low stimuli: relevance in asthma and COPD

BackgroundMacrophages are the predominant immune cells in the human lung and play a central role in airway inflammation, including asthma and chronic obstructive pulmonary disease (COPD). Thymic stromal lymphopoietin (TSLP), a pleiotropic cytokine mainly expressed by bronchial epithelial cells, plays a key role in asthma and COPD pathobiology. TSLP exists in two variants: the long form (lfTSLP) and a shorter TSLP isoform (sfTSLP). We aimed to localize TSLP in human lung macrophages (HLMs) and investigate the mechanisms of its release from these cells. We also evaluated the effects of the two variants of TSLP on the release of angiogenic factor from HLMs. MethodsWe employed immunofluorescence and Western blot to localize intracellular TSLP in HLMs purified from human lung parenchyma. HLMs were activated by T2-high (IL-4, IL-13) and T2-low (lipopolysaccharide: LPS) immunological stimuli. ResultsTSLP was detected in HLMs and subcellularly localized in the cytoplasm. IL-4 and LPS induced TSLP release from HLMs. Preincubation of macrophages with brefeldin A, known to disrupt the Golgi apparatus, inhibited TSLP release induced by LPS and IL-4. lfTSLP concentration-dependently induced the release of vascular endothelial growth factor-A (VEGF-A), the most potent angiogenic factor, from HLMs. sfTSLP neither activated nor interfered with the activating property of lfTSLP on macrophages. ConclusionsOur results highlight a novel immunologic circuit between HLMs and TSLP. Given the central role of macrophages in airway inflammation, this autocrine loop holds potential translational relevance in understanding innovative aspects of the pathobiology of asthma and chronic inflammatory lung disorders.

Asthma and hypertension: the role of airway inflammation.

Asthma is a chronic inflammatory respiratory disease often associated with comorbidities. Among cardiovascular comorbidities, arterial hypertension seems to create an additional health burden in asthmatics. However, evidence on this relationship is lacking. Our study aims to evaluate the characteristics of hypertensive asthmatics, focusing on the role of inflammation as a possible link between these diseases. We conducted a monocentric retrospective analysis consecutively including asthmatics who underwent induced sputum (IS) at our asthma referral center. Patients were divided in two groups according to presence or absence of history of hypertension. Clinical, functional, and inflammatory (airway and systemic) data were collected. Data on two hundred and sixty asthmatic patients were analyzed. Seventy-nine (30.4%) of them had a diagnosis of hypertension requiring a specific pharmacological treatment. Asthmatics with hypertension were more frequently male (p = 0.047), older (p < 0.001), and with higher body max index (BMI) (p < 0.001) when compared to normotensive patients. No difference concerning asthma control, severity and pharmacological treatment was observed between the two groups (all p > 0.05); distribution of comorbidities and lung function impairment (forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC); all p < 0.05) were statistically different between groups. Mixed granulocytic airway inflammation was prevalent in the hypertensive asthmatics (p = 0.014). Interestingly, a multivariable analysis revealed that age ≥ 65 years and an increased percentage of sputum neutrophils (≥61%) were independent predictors of hypertensive status (p < 0.001). Our data suggest that neutrophilic airway inflammation (as evaluated by induced sputum) is strictly associated with hypertension. In clinical practice, phenotyping asthmatic patients with comorbidities like hypertension could be useful also from a therapeutic point of view. Additional studies are mandatory to further elucidate the role of neutrophilic airway inflammation in asthma with cardiovascular diseases.

The effect of benralizumab on inflammation in severe asthma: a real-life analysis.

Benralizumab is a monoclonal antibody treatment for severe eosinophilic asthma (SEA). Few studies investigated its role in airway inflammation and its correlation with lung function. The aim of the present study is to assess its effect after 1 year of treatment, focusing on airway inflammation. This is a retrospective observational study, in an Italian tertiary reference centre specialised in diagnosis and management of severe asthma patients. We conducted a monocentric retrospective study including SEA patients treated with benralizumab for 1 year. Clinical, functional and inflammatory data were collected at baseline, 6 (T6) and 12 (T12) months. Twenty-two SEA patients on benralizumab were included. We observed a reduction in exacerbations rate and systemic steroid treatment (p < 0.0001) as well as an improvement in asthma control (p < 0.0001), health-related quality of life (p = 0.017) and lung function pre-BD FEV1 (L) (p = 0.02) and percentage (p = 0.004) and post-BD FEV1 (L) (p = 0.01) and percentage (p = 0.003) from baseline to T6 and T12. A reduction in sputum eosinophil percentage was observed at T6 and T12 (p < 0.005). We found a positive correlation between the variation of sputum eosinophils percentage and FEV1 (L) at T12 (rho = -0.79, p = 0.04). Moreover, the improvement of FEF25%-75% from baseline to 6 (rho = -0.53, p = 0.03) and 12 (rho = -0.62, p = 0.01) months negatively correlated with the duration of asthma disease.In our cohort 12/22 patients were super-responders at T6 and 15/22 at T12. Furthermore, clinical remission was reached by 12/22, and all of them obtained blood and sputum eosinophils counts normalisation. Our data confirm that it is a rapid and effective treatment for SEA acting on clinical, functional, systemic and airway inflammatory outcomes. Our results highlight the role of induced sputum as a promising non-invasive technique to investigate pathophysiologic mechanisms in severe asthma treated with biologics. Finally, a negative correlation between small airway improvement and the duration of asthma may suggest that a prompt referral to asthma centres may delay lung function worsening. Additional studies are needed to investigate more in-depth the role of induced sputum in the management of asthma, response to treatment and remission.

Association of size-fractionated particulate matters and their chemical constituents with airway inflammation and lung function among healthy children: A panel study

BackgroundEvidence is limited regarding size-fractionated particulate matters and their constituents responsible for children's respiratory health. ObjectiveTo investigate the short-term effects of size-fractionated particle number counts (PNCs) and their chemical constituents on airway inflammation and lung function in healthy children. MethodsWe conducted a longitudinal panel study involving 3 repeated surveys among 144 children aged 4–12 years in Guangzhou, China. Lung function and the fractional exhaled nitric oxide (FeNO) were measured during each visit. The real-time multi-size PNCs and their 23 constituent counts were obtained from the environmental monitoring station. We applied linear mixed-effects (LME) models, least absolute shrinkage and selection operator (LASSO) regression, and Bayesian kernel machine regression (BKMR) to evaluate the associations. ResultsEach interquartile range (IQR) increase in PNC0.5 was dose-responsive associated with 10.46% (95% CI: 2.54%, 18.98%) increase in FeNO at lag 0 day and 1.12% (95% CI: -1.90%, −0.33%) decrease in the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) at lag 1 day. But results for PNC1.0 and PNC2.5 were not significant. In LASSO regression models, K+, NH4+, and HSO4− were important predictors for FeNO, while Mg+, NH4+, and Mn+ were significant predictors for FEV1/FVC. Additionally, the overall effects of constituent mixture on higher FeNO or lower FEV1/FVC were robust when the mixture was above the 55th or 65th percentiles in PNC0.5 compared to the median. And a significant association between exposure to NH4+ and FeNO increment was identified, when setting all other constituents at the 25th, 50th and 75th percentiles. ConclusionShort-term exposure to PNC0.5 was dose-responsive related to increased FeNO and decreased FEV1/FVC among healthy children, and NH4+ in PNC0.5 might play a more dominant role in airway inflammation.

Myeloid-Specific SIRT6 Deletion Protects Against Particulate Matter (PM2.5)-Induced Airway Inflammation.

Particulate matter (PM2.5) is a common risk factor for airway inflammation. Alveolar macrophages play a critical role in airway inflammation. Sirtuin 6 (SIRT6) is a class Ill histone deacetylase that exerts an anti-inflammatory effect in airway diseases. However, the role of SIRT6 on PM2.5-induced airway inflammation in macrophages remains unclear. We aimed to determine whether SIRT6 protects against PM2.5-induced airway inflammation in macrophages. The effect of SIRT6 on PM2.5-induced airway inflammation was assessed by using THP1 cells or bone marrow-derived macrophages (BMDMs) exposed to PM2.5 in vitro and myeloid cell-specific SIRT6 conditional knockout mice (Sirt6fl/fl-LysMCre) in vivo. PM2.5 increased SIRT6 expression in THP1 cells, but SIRT6 gene silencing decreased PM2.5 induced inflammatory cytokines in THP1 cells. Moreover, the expression of SIRT6 and inflammatory cytokines was also decreased in BMDMs with myeloid-specific deletion of SIRT6 after stimulation of PM2.5. In vivo, Sirt6fl/fl-LysMCre mice substantially decreased airway inflammation in response to PM2.5 exposure. Our results revealed that SIRT6 promotes the PM2.5-induced airway inflammation in macrophages and indicated that inhibition of SIRT6 in macrophages may represent therapeutic strategy for airway disorders induced by airborne particulate pollution.

Eosinophilic Airway Diseases: From Pathophysiological Mechanisms to Clinical Practice.

Eosinophils play a key role in airway inflammation in many diseases, such as allergic and non-allergic asthma, chronic rhinosinusitis with nasal polyps, and chronic obstructive pulmonary disease. In these chronic disabling conditions, eosinophils contribute to tissue damage, repair, remodeling, and disease persistence through the production a variety of mediators. With the introduction of biological drugs for the treatment of these respiratory diseases, the classification of patients based on clinical characteristics (phenotype) and pathobiological mechanisms (endotype) has become mandatory. This need is particularly evident in severe asthma, where, despite the great scientific efforts to understand the immunological pathways underlying clinical phenotypes, the identification of specific biomarkers defining endotypes or predicting pharmacological response remains unsatisfied. In addition, a significant heterogeneity also exists among patients with other airway diseases. In this review, we describe some of the immunological differences in eosinophilic airway inflammation associated with severe asthma and other airway diseases and how these factors might influence the clinical presentation, with the aim of clarifying when eosinophils play a key pathogenic role and, therefore, represent the preferred therapeutic target.

An open microfluidic coculture model of fibroblasts and eosinophils to investigate mechanisms of airway inflammation.

Interactions between fibroblasts and immune cells play an important role in tissue inflammation. Previous studies have found that eosinophils activated with interleukin-3 (IL-3) degranulate on aggregated immunoglobulin G (IgG) and release mediators that activate fibroblasts in the lung. However, these studies were done with eosinophil-conditioned media that have the capacity to investigate only one-way signaling from eosinophils to fibroblasts. Here, we demonstrate a coculture model of primary normal human lung fibroblasts (HLFs) and human blood eosinophils from patients with allergy and asthma using an open microfluidic coculture device. In our device, the two types of cells can communicate via two-way soluble factor signaling in the shared media while being physically separated by a half wall. Initially, we assessed the level of eosinophil degranulation by their release of eosinophil-derived neurotoxin (EDN). Next, we analyzed the inflammation-associated genes and soluble factors using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and multiplex immunoassays, respectively. Our results suggest an induction of a proinflammatory fibroblast phenotype of HLFs following the coculture with degranulating eosinophils, validating our previous findings. Additionally, we present a new result that indicate potential impacts of activated HLFs back on eosinophils. This open microfluidic coculture platform provides unique opportunities to investigate the intercellular signaling between the two cell types and their roles in airway inflammation and remodeling.

Immunoglobulin A promotes IL-6 and IL-8 production, proliferation, and migration by the human bronchial smooth muscle cells

Immunoglobulin A (IgA) is important in biological defense, mainly in the mucosal area, and plays pathogenic roles in various diseases by activating both inflammatory and structural cells. The current study aimed to validate the effects of IgA on the human bronchial smooth muscle cell (BSMC), which plays a major role in airway inflammation and remodeling. Serum IgA induced interleukin (IL)-6 and IL-8 production at both mRNA and protein levels, and enhanced cell proliferation and migration by the BSMCs. The synthetic phenotype markers were regulated and the contractile phenotype markers were downregulated by serum IgA. Mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt, and nuclear factor-κB pathways were involved in IgA-induced IL-6 and IL-8 production. The BSMCs expressed transferrin receptor (TfR), and TfR siRNA transfection inhibited IL-6 and IL-8 production by serum IgA. In summary, serum IgA is a potent activator of the BSMCs at least partially via TfR.

A critical role for the RNA binding protein HuR in CD4+ T cell-mediated airway inflammation in mouse and human

Abstract The RNA-binding protein HuR (elavl1) positively regulates the expression of its targets by increasing mRNA stability and translation. Th2 and Th17 related genes play critical roles in airway inflammation in both mouse and human. Using in vitro and in vivo studies, we have previously shown that these proinflammatory genes are regulated by HuR. Here, we generated a conditional ablation of HuR in T cells (distal Lck-cre HuRfl/fl). We found significant decreases in Th2 differentiation, cytokine production, and lung inflammation in an alum-emulsified ovalbumin (ova-alum) model of allergic airway inflammation using this novel mouse model. We hypothesized that HuR might similarly regulate lung inflammation in human asthma. Using peripheral CD4+ T cells from 45 asthmatic patients, we found the inhibitory effect of the HuR-specific inhibitor CMLD-2, as well as an AMPK activator (acadesine aka AICAR), on both Th2/Th17 signature cytokines in both protein and mRNA levels. Our asthmatics were classified into type 2 high or non-type 2 high based on their blood eosinophil and FeNO levels. Interestingly, there were significant positive correlations between Th2 cytokine levels in CD4+ cells with levels of eosinophils and FeNO from asthmatics. Surprisingly, IFNγ (protein and mRNA) were also markedly decreased by HuR inhibition. Our bioinformatic studies also revealed proteins with high interaction with HuR including MAPK14/p38α and PTEN, common in the pathways with IFNγ, are affected by HuR inhibitor. Taken together, our mouse and human data suggest that HuR plays a crucial permissive role in both allergen- and nonallergen-driven airway inflammation by regulating key genes and that interfering with its function may be a novel way to treat asthma. Supported by R01: AI080870, R21: AI079341

Silencing of FSTL1 Alleviated LPS-Induced Inflammatory Damage and Oxidative Damage in Human Bronchial Epithelial Cells via BMP4/KLF4 Axis

Introduction: Childhood asthma is a common chronic inflammatory lung disease in children, among which airway inflammation is the main driving factor of asthma symptoms. Follistatin-like protein 1 (FSTL1) is involved in multiple inflammatory processes, but its role in airway inflammation has not been fully elucidated. Methods: We used lipopolysaccharide (LPS) to stimulate human primary bronchial epithelial (BEAS-2B) cells to establish an in vitro airway inflammation model. The expression of FSTL1 was detected by qPCR. Cell Counting Kit-8 and Annexin V-PI double staining was used to analyze the viability and apoptosis of BEAS-2B. The content of IL-6, IL-8 and TNF-α was determined by ELISA kit. Western blot was used to detect the protein expression level of the bone morphogenetic protein 4 (BMP4) and KLF4. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde were measured to assess oxidative stress. Results: The mRNA expression of FSTL1 was significantly increased in LPS-treated BEAS-2B cells. Silencing of FSTL1 inhibited the release of IL-6, IL-8, TNF-α, and cell apoptosis as well as enhanced the activities of SOD, CAT, and GSH-Px. Silencing of FSTL1 reversed the inflammatory state of cells by upregulating BMP4 and increasing the expression level of KLF4. Conclusion: Silencing of FSTL1 reduced LPS-induced BEAS-2B cell damage by regulating the BMP4/KLF4 axis. FSTL1 may be a potential target for the treatment of asthma.

Sigma-1 Receptor Alleviates Airway Inflammation and Airway Remodeling Through AMPK/CXCR4 Signal Pathway.

Sigma non-opioid intracellular receptor 1 (Sigma-1R) has been proven to play a major role in inflammation and structural remodeling. However, its role in airway inflammation and airway remodeling remains unclear. The purpose of this study aimed to explore the role and mechanism of Sigma-1R in airway remodeling and epithelial-mesenchymal transition (EMT) process in vivo and in vitro. We observed the decrease of Sigma-1R in lung tissue of asthma model. In the mouse model of allergic airway inflammation (AAI), Sigma-1R agonist RPE-084 significantly relieved airway inflammation and airway remodeling, while Sigma-1R antagonist BD1047 (B8562) had opposite effects. Further research showed that RPE-084 treatment increased the expression of pAMPK and inhibited the expression of CXCR4. Furthermore, RPE-084 treatment suppressed the levels of IL-4, IL-5, and IL-13 in BALF. We found that RPE-084 or Sigma-1R overexpression vector treatment regulated cell cycle and inhibited cell proliferation, migration, and EMT process in TGF-β1-induced 16HBE cells. Finally, we confirmed that AMP-activated protein kinase (AMPK) inhibitor compound C or CXCR4 agonist ATI-2341 both reversed the effects of Sigma-1R on TGF-β1-induced 16 HBE cells. In a word, our research shows that Sigma-1R is helpful to improve airway remodeling of asthma, and emphasizes a new candidate molecular for asthma treatment.

Follistatin-Like 1 Induces the Activation of Type 2 Innate Lymphoid Cells to Promote Airway Inflammation in Asthma.

Asthma is a chronic disease closely related to airway inflammation. It has been proven that type 2 innate lymphoid cells (ILC2s) play an essential role in airway inflammation in asthma. Furthermore, there is growing evidence that Follistatin-like 1 (FSTL1) can participate in various inflammatory reactions mediated by the JAK/STAT signaling pathway, among others. Therefore, we put forward a new hypothesis: FSTL1 promotes asthmatic airway inflammation by activating ILC2. This study generated an ovalbumin-sensitized asthma model in C57BL/6 and Fstl1+/- mice. The results showed that the absolute number and the proportion of ILC2 in the ovalbumin-challenged Fstl1+/- group were lower than in the ovalbumin-challenged wild-type group. We also measured the levels of Th2-type cytokines in the serum and bronchoalveolar lavage fluid (BALF) of mice and found that the corresponding cytokines in the Fstl1+/- were lower than in the wild-type groups. Finally, we tested whether MEK-JAK-STAT-GATA3 is the specific pathway for FSTL1 to activate ILC2, and further tested our working hypothesis by adding various inhibitors of proteins from this pathway. Overall, these findings reveal that FSTL1 can activate ILC2 through MEK-JAK-STAT-GATA3 to promote airway inflammation and participate in the pathogenesis of asthma.