Transforming growth factor β and severe asthma: a perfect storm

Identification of candidate genes and molecular mechanisms related to asthma progression using bioinformatics

BACKGROUND

Asthma is a heterogeneous disorder. This study aimed to identify changes in gene expression and molecular mechanisms associated with moderate to severe asthma.

METHODS

Differentially expressed genes (DEGs) were analyzed in GSE69683 dataset among moderate asthma and its controls as well as between severe asthma and moderate asthma. Key module genes were identified via co-expression analysis, and the molecular mechanism of the module genes was explored through enrichment analysis and gene set enrichment analysis (GSEA). GSE89809 was used to verify the characteristic genes related to moderate and severe asthma.

RESULTS

Accordingly, 2540 DEGs were present between moderate asthma and the control group, while 6781 DEGs existed between severe asthma and moderate asthma. These genes were identified into 14 co-expression modules. Module 7 had the highest positive correlation with severe asthma and was recognized to be a key module by STEM. Enrichment analysis demonstrated that the module genes were mainly involved in oxidative stress-related signaling pathways. The expression of HSPA1A, PIK3CG and PIK3R6 was associated with moderate asthma, while MAPK13 and MMP9 were associated with severe asthma. The AUC values were verified by GSE89809. Additionally, 322 drugs were predicted to target five genes.

CONCLUSION

These results identified characteristic genes related to moderate and severe asthma and their corresponding molecular mechanisms, providing a basis for future research.

The Role of Transforming Growth Factor-β (TGF-β) in Asthma and Chronic Obstructive Pulmonary Disease (COPD)

Asthma and chronic obstructive pulmonary disease (COPD) represent chronic inflammatory respiratory disorders that, despite having distinct pathophysiological underpinnings, both feature airflow obstruction and respiratory symptoms. A critical component in the pathogenesis of each condition is the transforming growth factor-β (TGF-β), a multifunctional cytokine that exerts varying influences across these diseases. In asthma, TGF-β is significantly involved in airway remodeling, a key aspect marked by subepithelial fibrosis, hypertrophy of the smooth muscle, enhanced mucus production, and suppression of emphysema development. The cytokine facilitates collagen deposition and the proliferation of fibroblasts, which are crucial in the structural modifications within the airways. In contrast, the role of TGF-β in COPD is more ambiguous. It initially acts as a protective agent, fostering tissue repair and curbing inflammation. However, prolonged exposure to environmental factors such as cigarette smoke causes TGF-β signaling malfunction. Such dysregulation leads to abnormal tissue remodeling, marked by excessive collagen deposition, enlargement of airspaces, and, thus, accelerated development of emphysema. Additionally, TGF-β facilitates the epithelial-to-mesenchymal transition (EMT), a process contributing to the phenotypic alterations observed in COPD. A thorough comprehension of the multifaceted role of TGF-β in asthma and COPD is imperative for elaborating precise therapeutic interventions. We review several promising approaches that alter TGF-β signaling. Nevertheless, additional studies are essential to delineate further the specific mechanisms of TGF-β dysregulation and its potential therapeutic impacts in these chronic respiratory diseases.

Association of Obesity and Severe Asthma in Adults

The incidence of obesity and asthma continues to enhance, significantly impacting global public health. Adipose tissue is an organ that secretes hormones and cytokines, causes meta-inflammation, and contributes to the intensification of bronchial hyperreactivity, oxidative stress, and consequently affects the different phenotypes of asthma in obese people. As body weight increases, the risk of severe asthma increases, as well as more frequent exacerbations requiring the use of glucocorticoids and hospitalization, which consequently leads to a deterioration of the quality of life. This review discusses the relationship between obesity and severe asthma, the underlying molecular mechanisms, changes in respiratory function tests in obese people, its impact on the occurrence of comorbidities, and consequently, a different response to conventional asthma treatment. The article also reviews research on possible future therapies for severe asthma. The manuscript is a narrative review of clinical trials in severe asthma and comorbid obesity. The articles were found in the PubMed database using the keywords asthma and obesity. Studies on severe asthma were then selected for inclusion in the article. The sections: 'The classification connected with asthma and obesity', 'Obesity-related changes in pulmonary functional tests', and 'Obesity and inflammation', include studies on subjects without asthma or non-severe asthma, which, according to the authors, familiarize the reader with the pathophysiology of obesity-related asthma.

Scutellarin Alleviates Ovalbumin-Induced Airway Remodeling in Mice and TGF-β-Induced Pro-fibrotic Phenotype in Human Bronchial Epithelial Cells via MAPK and Smad2/3 Signaling Pathways

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness (AHR), inflammation, and remodeling. Epithelial-mesenchymal transition (EMT) is an essential player in these alterations. Scutellarin is isolated from Erigeron breviscapus. Its vascular relaxative, myocardial protective, and anti-inflammatory effects have been well established. This study was designed to detect the biological roles of scutellarin in asthma and its related mechanisms. The asthma-like conditions were induced by ovalbumin challenges. The airway resistance and dynamic compliance were recorded as the results of AHR. Bronchoalveolar lavage fluid (BALF) was collected and processed for differential cell counting. Hematoxylin and eosin staining, periodic acid-Schiff staining, and Masson staining were conducted to examine histopathological changes. The levels of asthma-related cytokines were measured by enzyme-linked immunosorbent assay. For in vitro analysis, the 16HBE cells were stimulated with 10 ng/mL transforming growth beta-1 (TGF-β1). Cell migration was estimated by Transwell assays and wound healing assays. E-cadherin, N-cadherin, and α-smooth muscle actin (α-SMA) were analyzed by western blotting, real-time quantitative polymerase chain reaction, immunofluorescence staining, and immunohistochemistry staining. The underlying mechanisms of the mitogen-activated protein kinase (MAPK) and Smad pathways were investigated by western blotting. In an ovalbumin-induced asthmatic mouse model, scutellarin suppressed inflammation and inflammatory cell infiltration into the lungs and attenuated AHR and airway remodeling. Additionally, scutellarin inhibited airway EMT (upregulated E-cadherin level and downregulated N-cadherin and α-SMA) in ovalbumin-challenged asthmatic mice. For in vitro analysis, scutellarin prevented the TGF-β1-induced migration and EMT in 16HBE cells. Mechanistically, scutellarin inhibits the phosphorylation of Smad2, Smad3, ERK, JNK, and p38 in vitro and in vivo. In conclusion, scutellarin can inactivate the Smad/MAPK pathways to suppress the TGF-β1-stimulated epithelial fibrosis and EMT and relieve airway inflammation and remodeling in asthma. This study provides a potential therapeutic strategy for asthma.

Eosinophil peroxidase promotes bronchial epithelial cells to secrete asthma-related factors and induces the early stage of airway remodeling

Asthma is a heterogeneous disease characterized by chronic airway inflammation, reversible airflow limitation, and airway remodeling. Eosinophil peroxidase (EPX) is the most abundant secondary granule protein unique to activated eosinophils. In this study, we aimed to illustrate the effect of EPX on the epithelial-mesenchymal transition (EMT) in BEAS-2B cells. Our research found that both EPX and ADAM33 were negatively correlated with FEV1/FVC and FEV1%pred, and positively correlated with IL-5 levels. Asthma patients had relatively higher levels of ADAM33 and EPX compared to the healthy control group. The expression of TSLP, TGF-β1 and ADAM33 in the EPX intervention group was significantly higher. Moreover, EPX could promote the proliferation, migration and EMT of BEAS-2B cells, and the effect of EPX on various factors was significantly improved by the PI3K inhibitor LY294002. The findings from this study could potentially offer a novel therapeutic target for addressing airway remodeling in bronchial asthma, particularly focusing on EMT.

Bakuchicin alleviates ovalbumin-induced allergic asthma by regulating M2 macrophage polarization

OBJECTIVE

Asthma is an airway inflammatory disease caused by activation of numerous immune cells including macrophages. Bakuchicin (BKC) is known to exhibit anti-inflammatory effects and type 2 T helper (Th2) regulation, but has not been investigated for airway inflammation. This study aimed to evaluate the effects of BKC on airway inflammation and demonstrate the mechanisms of macrophage polarization.

METHODS

The anti-inflammatory effects were determined using lipopolysaccharide (LPS)-stimulated macrophages. The ovalbumin (OVA)-induced asthma mouse model was used to evaluate the effects of BKC on airway inflammation and Th2 responses. Moreover, the effect of BKC on macrophage polarization was confirmed in bone marrow-derived macrophages (BMDMs) differentiation.

RESULTS

BKC suppressed nitric oxide production and expression of pro-inflammatory cytokines by inhibiting signaling pathway in LPS-stimulated macrophages. In an OVA-induced asthma model, BKC treatment alleviated histological changes and mast cell infiltration and reduced the levels of eosinophil peroxidase, β-hexosaminidase, and immunoglobulin levels. In addition, BKC alleviated Th2 responses and M2 macrophage populations in bronchoalveolar fluid. In BMDMs, BKC suppressed IL-4-induced M2 macrophage polarization and the expression of M2 markers such as arginase-1 and Fizz-1 through inhibiting sirtuin 2 levels.

CONCLUSION

BKC could be a drug candidate for the treatment of allergic asthma.

TGF-β, IL-1β, IL-6 levels and TGF-β/Smad pathway reactivity regulate the link between allergic diseases, cancer risk, and metabolic dysregulations

The risk of cancer is higher in patients with asthma compared to those with allergic rhinitis for many types of cancer, except for certain cancers where a contrasting pattern is observed. This study offers a potential explanation for these observations, proposing that the premalignant levels of circulating transforming growth factor-β (TGF-β), IL-1β, and IL-6 as well as the reactivity of the TGF-β/Smad signaling pathway at the specific cancer site, are crucial factors contributing to the observed disparities. Circulating TGF-β, IL- β and IL-6 levels also help clarify why asthma is positively associated with obesity, Type 2 diabetes, hypertension, and insulin resistance, whereas allergic rhinitis is negatively linked to these conditions. Furthermore, TGF-β/Smad pathway reactivity explains the dual impact of obesity, increasing the risk of certain types of cancer while offering protection against other types of cancer. It is suggested that the association of asthma with cancer and metabolic dysregulations is primarily linked to the subtype of neutrophilic asthma. A binary classification of TGF-β activity as either high (in the presence of IL-1β and IL-6) or low (in the presence or absence of IL-1β and IL-6) is proposed to differentiate between allergy patients prone to cancer and metabolic dysregulations and those less prone. Glycolysis and oxidative phosphorylation, the two major metabolic pathways utilized by cells for energy exploitation, potentially underlie this dichotomous classification by reprogramming metabolic pathways in immune cells.

LINC00158 modulates the function of BEAS-2B cells via targeting BCL11B and ameliorates OVA-LPS-induced severe asthma in mice models

Persistent type (T) 2 airway inflammation plays an important role in the development of severe asthma. However, the molecular mechanisms leading to T2 severe asthma have yet to be fully clarified. Human normal lung epithelial cells (BEAS-2B cells) were transfected with LINC00158/BCL11B plasmid/small interfering RNA (siRNA). Levels of epithelial-mesenchymal transition (EMT)-related markers were measured using real-time qPCR (RT-qPCR) and western blot. A dual luciferase reporter assay was used to validate the targeting relationship between LINC00158 and BCL11B. The effects of LINC00158-lentivirus vector-mediated overexpression and dexamethasone on ovalbumin (OVA)/lipopolysaccharide (LPS)-induced severe asthma were investigated in mice in vivo. Our study showed that overexpression of LINC00158/BCL11B inhibited the levels of EMT-related proteins, apoptosis, and promoted the proliferation of BEAS-2B cells. BCL11B was a direct target of LINC00158. And LINC00158 targeted BCL11B to regulate EMT, apoptosis, and cell proliferation of BEAS-2B cells. Compared with severe asthma mice, LINC00158 overexpression alleviated OVA/LPS-induced airway hyperresponsiveness and airway inflammation, including reductions in T helper 2 cells factors in lung tissue and BALF, serum total- and OVA-specific IgE, inflammatory cell infiltration, and goblet cells hyperplasia. In addition, LINC00158 overexpression alleviated airway remodeling, including reduced plasma TGF-β1 and collagen fiber deposition, as well as suppression of EMT. Additionally, overexpression of LINC00158 enhanced the therapeutic effect of dexamethasone in severe asthmatic mice models. LINC00158 regulates BEAS-2B cell biological function by targeting BCL11B. LINC00158 ameliorates T2 severe asthma in vivo and provides new insights into the clinical treatment of severe asthma.

The epithelium takes the stage in asthma and inflammatory bowel diseases

The epithelium is a dynamic barrier and the damage to this epithelial layer governs a variety of complex mechanisms involving not only epithelial cells but all resident tissue constituents, including immune and stroma cells. Traditionally, diseases characterized by a damaged epithelium have been considered "immunological diseases," and research efforts aimed at preventing and treating these diseases have primarily focused on immuno-centric therapeutic strategies, that often fail to halt or reverse the natural progression of the disease. In this review, we intend to focus on specific mechanisms driven by the epithelium that ensure barrier function. We will bring asthma and Inflammatory Bowel Diseases into the spotlight, as we believe that these two diseases serve as pertinent examples of epithelium derived pathologies. Finally, we will argue how targeting the epithelium is emerging as a novel therapeutic strategy that holds promise for addressing these chronic diseases.

Endotypic heterogeneity and pathogenesis in chronic rhinosinusitis

PURPOSE OF REVIEW

This review aims to provide updates in realms of endotypic heterogeneity, pathogenesis at the molecular level, potential of biomarkers, and cutting-edge scope of biologics in CRS.

RECENT FINDINGS

High-dimensional analyses, such as transcriptomes, and machine learning, have significantly enhanced CRS endotyping, uncovering diverse pathogenetic mechanisms contributing to its heterogeneity. The dynamic process of epithelial remodeling in CRS pathogenesis has gained more clarity and support as exemplified by IL-13 and oncostatin M (OSM) that are shown intricately linked to epithelial barrier dysfunction. Moreover, anti-dsDNA autoantibody, BAFF, periostin, and cystatin SN show promise as potentials biomarkers, offering diagnostic and prognostic value for CRS.

SUMMARY

The identification of inflammatory molecules involved in endotype specific signaling pathways provides insights into the underlying mechanisms and verifiable biomarkers for diagnosis and prediction of disease severity. More comprehensive clinical studies should be conducted to facilitate biologics from bench to bedside in treating CRS.

Expression of constitutively active TβRI leads to attenuation of ovalbumin-induced allergic airway inflammation associated with augmented M2 polarization of alveolar macrophage

BACKGROUND

Transforming growth factor-β (Tgf-β) plays an important role in the pathogenesis of asthma through the regulation of T cells and airway epithelium. Its functions in alveolar macrophage (AM) during allergic airway inflammation remain unknown.

METHODS

A murine asthma model was induced with ovalbumin (ova) in TβRICA/Fsp1-Cre transgenic mice expressing constitutively active Tgf-β receptor type I (TβRICA) under the control of Fsp1-Cre transgene. Cells in the bronchoalveolar lavage (BAL) were collected to study immune cell infiltration in the lungs. Cytokine levels in BAL fluid were measured by enzyme-linked immunoassay (ELISA). Lungs were sectioned and stained with hematoxylin and eosin, periodic acid-Schiff, and trichrome for histopathologic evaluation. AMs were assessed by flow cytometry and were sorted for quantitative polymerase chain reaction analysis.

RESULTS

Our data indicated that TβRICA transcripts were induced in AMs of TβRICA/Fsp1-Cre mice. Following the ova challenges, TβRICA/Fsp1-Cre mice exhibited reduced cellular infiltration of the airway, reduced pulmonary fibrosis, and reduced bronchial mucus secretion as compared to ova-challenged wild-type mice. An alternatively activated macrophage (M2) polarization was significantly elevated in the lungs of ova-challenged TβRICA/Fsp1-Cre mice as reflected by increased numbers of AMs expressing M2 subtype marker, CD163, in the lungs and enhanced expression of CCR2 and CD206 in AMs. Moreover, TβRICA/Fsp1-Cre AMs showed augmented expression of transcription factors, Foxo1, and IRF4, which are known to be positive regulators for M2 polarization.

CONCLUSIONS

Expression of TβRICA in AMs promoted M2 polarization and ameliorated allergic airway inflammation in an ova-induced asthma mouse model.

Research progress on the mechanism of astragaloside IV in the treatment of asthma

Asthma is a common chronic respiratory disease, and its treatment is a core problem and challenge in clinical practice. Glucocorticoids (GCs) are the first-line therapy for the treatment of asthma. Local and systemic adverse reactions caused by GCs create obstacles to the treatment of asthma. Therefore, the research target is to find a new, safe, and effective therapeutic medicine at present. Natural products are an important source for treating asthma with low cost and low toxicity. Astragaloside IV (AS-IV) is an active ingredient of traditional Chinese medicine Astragalus mongholicus Bunge. Previous studies have indicated that AS-IV plays a therapeutic role in the treatment of asthma by inhibiting airway inflammation and remodeling the airway, and by regulating immunity and neuroendocrine function (Fig. 1) . It has a variety of biological characteristics such as multi-target intervention, high safety, and good curative effect. This article reviews the specific mechanism of AS-IV for the treatment of asthma to provide references for subsequent research.

Lignosus rhinocerotis extract ameliorates airway inflammation and remodelling via attenuation of TGF-β1 and Activin A in a prolonged induced allergic asthma model

Allergic asthma is associated with chronic airway inflammation and progressive airway remodelling. The sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden (Tiger Milk mushroom) is used traditionally to treat various illnesses, including asthma in Southeast Asia. This study was carried out to evaluate the effect of L. rhinocerotis extract (LRE) on airway inflammation and remodelling in a chronic model of asthma. The present study investigated the therapeutic effects of LRE on airway inflammation and remodelling in prolonged allergen challenged model in allergic asthma. Female Balb/C mice were sensitised using ovalbumin (OVA) on day 0 and 7, followed by OVA-challenged (3 times/week) for 2, 6 and 10 weeks. LRE (125, 250, 500 mg/kg) were administered by oral gavage one hour after every challenge. One group of mice were left untreated after the final challenge for two weeks. LRE suppressed inflammatory cells and Th2 cytokines (IL-4, IL-5 and IL-13) in BALF and reduced IgE level in the serum. LRE also attenuated eosinophils infiltration and goblet cell hyperplasia in the lung tissues; as well as ameliorated airway remodelling by reducing smooth muscle thickness and reducing the expressions of TGF-β1 and Activin A positive cell in the lung tissues. LRE attenuated airway inflammation and remodelling in the prolonged allergen challenge of allergic asthma model. These findings suggest the therapeutic potential of LRE as an alternative for the management of allergic asthma.

Mediation of endoplasmic reticulum stress and NF-κB signaling pathway in DINP-exacerbated allergic asthma: A toxicological study with Balb/c mice

Epidemiological evidence indicates a significant relationship between exposure to diisononyl phthalate and allergic asthma. Despite this, the mechanism underlying this association remains unclear. Previous toxicological researches have suggested that the development of allergic asthma may involve the activation of endoplasmic reticulum stress (ERS) and the nuclear factor κ-B (NF-κB) pathways. Nevertheless, it is currently unknown whether these specific signaling pathways are implicated in diisononyl phthalate (DINP)-induced allergic asthma. The objective of this research was to understand how DINP exacerbates allergic asthma in Balb/c mice through ERS and NF-κB pathways. To systematically examine the aggravated effects of DINP in Balb/c mice, we measured airway hyperresponsiveness (AHR), lung tissue pathology, cytokines, and ERS and NF-κB pathway biomarkers. Additionally, we applied the ERS antagonist phenylbutyric acid (4-PBA) or the NF-κB antagonist pyrrolidine dithiocarbamate (PDTC) to verify the mediating effects of ERS and NF-κB on DINP-exacerbated allergic asthma. The results of our experiment show that oral DINP exposure may exacerbate airway hyperresponsiveness and airway remodeling. This deterioration is accompanied by an imbalance in immunoglobulin levels, Th17/Treg cells, ERS, and NF-κB biomarkers, leading to the activation of pro-inflammatory pathways. Furthermore, our study found that the blocking effect of 4-PBA or PDTC can inhibit the Th17/Treg imbalance and effectively alleviate symptoms resembling allergic asthma. In conclusion, ERS and NF-κB signaling pathways play an important role in regulating DINP-induced allergic asthma exacerbations.

A dynamical model of TGF-β activation in asthmatic airways

Excessive activation of the regulatory cytokine transforming growth factor $\beta $ (TGF-$\beta $) via contraction of airway smooth muscle (ASM) is associated with the development of asthma. In this study, we develop an ordinary differential equation model that describes the change in density of the key airway wall constituents, ASM and extracellular matrix (ECM), and their interplay with subcellular signalling pathways leading to the activation of TGF-$\beta $. We identify bistable parameter regimes where there are two positive steady states, corresponding to either reduced or elevated TGF-$\beta $ concentration, with the latter leading additionally to increased ASM and ECM density. We associate the former with a healthy homeostatic state and the latter with a diseased (asthmatic) state. We demonstrate that external stimuli, inducing TGF-$\beta $ activation via ASM contraction (mimicking an asthmatic exacerbation), can perturb the system irreversibly from the healthy state to the diseased one. We show that the properties of the stimuli, such as their frequency or strength, and the clearance of surplus active TGF-$\beta $, are important in determining the long-term dynamics and the development of disease. Finally, we demonstrate the utility of this model in investigating temporal responses to bronchial thermoplasty, a therapeutic intervention in which ASM is ablated by applying thermal energy to the airway wall. The model predicts the parameter-dependent threshold damage required to obtain irreversible reduction in ASM content, suggesting that certain asthma phenotypes are more likely to benefit from this intervention.

Broncho-Vaxom bacterial lysate prevents asthma via acetate enhancement in mouse model

PURPOSE

Broncho-Vaxom (BV) is known to attenuate allergic airway inflammation and chronic bronchitis in humans, but the underlying mechanism of this gut-mediated immunity remains unclear. This study investigated the effects of an oral BV on gut and systemic short-chain fatty acids (SCFAs) and immune responses.

METHODS

Oral BV was administered daily for 15 days prior to commencing the study in an asthma mouse model. Asthma was induced by ovalbumin (OVA) sensitization followed by a challenge with 1% OVA by inhalation. Asthmatic phenotypes, gut- and systemic- immune responses, and SCFAs in the cecum and blood were then investigated.

RESULTS

Airway hyperresponsiveness, total immunoglobulin E production, and pulmonary inflammation were all significantly suppressed by BV. The interleukin-13 level was also suppressed, whereas TGF-β expression was increased, in the lungs of the BV-treated mice. The regulatory T (Treg) cell numbers were increased in the small intestine, and the acetate level was increased in the cecum and serum after BV treatment. The levels of acetate in the cecum and serum were negatively correlated with airway hyperresponsiveness and with the eosinophil numbers in the BAL fluid of the OVA-induced mice. There was a positive correlation between the acetate levels in the feces and serum and the lung expression of TGF-β in the asthma mice.

CONCLUSIONS

Oral BV administration appears to prevent allergic inflammation by enhancing Treg cell proliferation and acetate production in an asthmatic mouse model.

Oropharyngeal Microbiota Clusters in Children with Asthma or Wheeze Associate with Allergy, Blood Transcriptomic Immune Pathways, and Exacerbation Risk

Rationale: Children with preschool wheezing or school-age asthma are reported to have airway microbial imbalances. Objectives: To identify clusters in children with asthma or wheezing using oropharyngeal microbiota profiles. Methods: Oropharyngeal swabs from the U-BIOPRED (Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes) pediatric asthma or wheezing cohort were characterized using 16S ribosomal RNA gene sequencing, and unsupervised hierarchical clustering was performed on the Bray-Curtis β-diversity. Enrichment scores of the Molecular Signatures Database hallmark gene sets were computed from the blood transcriptome using gene set variation analysis. Children with severe asthma or severe wheezing were followed up for 12-18 months, with assessment of the frequency of exacerbations. Measurements and Main Results: Oropharyngeal samples from 241 children (age range, 1-17 years; 40% female) revealed four taxa-driven clusters dominated by Streptococcus, Veillonella, Rothia, and Haemophilus. The clusters showed significant differences in atopic dermatitis, grass pollen sensitization, FEV1% predicted after salbutamol, and annual asthma exacerbation frequency during follow-up. The Veillonella cluster was the most allergic and included the highest percentage of children with two or more exacerbations per year during follow-up. The oropharyngeal clusters were different in the enrichment scores of TGF-β (transforming growth factor-β) (highest in the Veillonella cluster) and Wnt/β-catenin signaling (highest in the Haemophilus cluster) transcriptomic pathways in blood (all q values <0.05). Conclusions: Analysis of the oropharyngeal microbiota of children with asthma or wheezing identified four clusters with distinct clinical characteristics (phenotypes) that associate with risk for exacerbation and transcriptomic pathways involved in airway remodeling. This suggests that further exploration of the oropharyngeal microbiota may lead to novel pathophysiologic insights and potentially new treatment approaches.

Genetic Variants Associated with Bronchial Asthma Specific to the Population of the Russian Federation

Bronchial asthma (BA) is a disease that still lacks an exhaustive treatment protocol. In this regard, the global medical community pays special attention to the genetic prerequisites for the occurrence of this disease. Therefore, the search for the genetic polymorphisms underlying bronchial asthma has expanded considerably. As the present study progressed, a significant amount of scientific medical literature was analyzed and 167 genes reported to be associated with the development of bronchial asthma were identified. A group of participants (n = 7,303) who had voluntarily provided their biomaterial (venous blood) to be used in the research conducted by the Federal Medical Biological Agency of Russia was formed to subsequently perform a bioinformatic verification of known associations and search for new ones. This group of participants was divided into four cohorts, including two sex-distinct cohorts of individuals with a history of asthma and two sex-distinct cohorts of apparently healthy individuals. A search for polymorphisms was made in each cohort among the selected genes, and genetic variants were identified whose difference in occurrence in the different cohorts was statistically significant (significance level less than 0.0001). The study revealed 11 polymorphisms that affect the development of asthma: four genetic variants (rs869106717, rs1461555098, rs189649077, and rs1199362453), which are more common in men with bronchial asthma compared to apparently healthy men; five genetic variants (rs1923038536, rs181066119, rs143247175, rs140597386, and rs762042586), which are more common in women with bronchial asthma compared to apparently healthy women; and two genetic variants (rs1219244986 and rs2291651) that are rare in women with a history of asthma.

Nrf2 regulates downstream genes by targeting miR-29b in severe asthma and the role of grape seed proanthocyanidin extract in a murine model of steroid-insensitive asthma

CONTEXT

Grape seed proanthocyanidin extract (GSPE) is effective in treating severe asthma (SA).

OBJECTIVE

To examine the relationship between Nrf2-miR-29b axis and SA, and to detect whether preventive use of GSPE relieves SA via it.

MATERIALS AND METHODS

We recruited 10 healthy controls, 10 patients with non-severe asthma (nSA), and 9 patients with SA from February 2017 to December 2017. Peripheral blood mononuclear cells from these volunteers were extracted. A murine model of steroid-insensitive asthma was established in six-week-old female BALB/c mice that were sensitised and challenged with OVA, Al(OH)₃ and LPS for 31 days. Mice in the treated groups were injected with DXM (5 mg/kg/d), with or without GSPE (100 mg/kg/d). Control group received PBS. We performed quantitative real-time PCR, western blot and luciferase reporter assay in animal and cell models.

RESULTS

SA group demonstrated significantly lower concentrations of Nrf2 protein, Nrf2 mRNA, and miR-29b than nSA group and control group. Conversely, higher levels of platelet derived growth factor C (PDGFC), phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), and collagen type III alpha 1 (COL3A1) were measured in SA than in the other two groups. PDGFC, PIK3R1, and COL3A1 were the target genes of miR-29b. GSPE + DXM significantly elevated the expression of Nrf2 (+188%), Nrf2 mRNA (+506%), and miR-29b (+201%), and significantly reduced the expression of PDGFC (-72%), PIK3R1 (-40%), and COL3A1 (-65%) compared with OVA + LPS.

CONCLUSIONS

Nrf2-miR-29b axis is involved in the pathogenesis of SA. GSPE, as an adjuvant drug, maybe a potential therapeutic agent for SA.

Hedgehog Signaling as a Therapeutic Target for Airway Remodeling and Inflammation in Allergic Asthma

Genome-wide association studies (GWAS) have shown that variants of patched homolog 1 (PTCH1) are associated with lung function abnormalities in the general population. It has also been shown that sonic hedgehog (SHH), an important ligand for PTCH1, is upregulated in the airway epithelium of patients with asthma and is suggested to be involved in airway remodeling. The contribution of hedgehog signaling to airway remodeling and inflammation in asthma is poorly described. To determine the biological role of hedgehog signaling-associated genes in asthma, gene silencing, over-expression, and pharmacologic inhibition studies were conducted after stimulating human airway epithelial cells or not with transforming growth factor β1 (TGFβ1), an important fibrotic mediator in asthmatic airway remodeling that also interacts with SHH pathway. TGFβ1 increased hedgehog-signaling-related gene expression including SHH, GLI1 and GLI2. Knockdown of PTCH1 or SMO with siRNA, or use of hedgehog signaling inhibitors, consistently attenuated COL1A1 expression induced by TGFβ1 stimulation. In contrast, Ptch1 over-expression augmented TGFβ1-induced an increase in COL1A1 and MMP2 gene expression. We also showed an increase in hedgehog-signaling-related gene expression in primary airway epithelial cells from controls and asthmatics at different stages of cellular differentiation. GANT61, an inhibitor of GLI1/2, attenuated TGFβ1-induced increase in COL1A1 protein expression in primary airway epithelial cells differentiated in air–liquid interface. Finally, to model airway tissue remodeling in vivo, C57BL/6 wildtype (WT) and Ptch1^+/− mice were intranasally challenged with house dust mite (HDM) or phosphate-buffered saline (PBS) control. Ptch1^+/− mice showed reduced sub-epithelial collagen expression and serum inflammatory proteins compared to WT mice in response to HDM challenge. In conclusion, TGFβ1-induced airway remodeling is partially mediated through the hedgehog signaling pathway via the PTCH1-SMO-GLI axis. The Hedgehog signaling pathway is a promising new potential therapeutic target to alleviate airway tissue remodeling in patients with allergic airways disease.

Cytokines Profile and Lung Function in Children with Obesity and Asthma: A Case Control Study

The existence of common inflammatory biomarkers linking obesity and asthma in children has been hypothesized. Nevertheless, laboratory and clinical characteristics of children with obesity and asthma are still poorly defined. The primary aim of the present study is to investigate the lung function and the cytokine profile, in children with obesity and asthma. In this prospective, cross-sectional pilot study, pulmonary function tests, biochemical parameters, and serum cytokines levels were compared in three groups of 28 children each, matched for age and sex. Obese children showed normal forced spirometry values except an increased distal airway resistance in subjects with obesity and no asthma. Both groups including obese children showed higher leptin and IL-10 levels and lower adiponectin and TNF-alpha levels compared to children with no obesity and asthma. IL-33 and TGF-beta1 levels were higher in children with obesity and asthma vs. children with normal weight and asthma. Finally, IL-6 was undetectable in approximately 70% of obese children with no asthma, in 57% obese asthmatic children and in 100% of children with normal-weight and asthma. Children with obesity and asthma show the most striking cytokine profile, suggesting a pro-inflammatory role of fat mass in asthma development.

House dust mite-induced Akt-ERK1/2-C/EBP beta pathway triggers CCL20-mediated inflammation and epithelial-mesenchymal transition for airway remodeling

House dust mite (HDM) allergens cause inflammatory responses and chronic allergic diseases such as bronchial asthma and atopic dermatitis. Here, we investigate the mechanism by which HDM induces C-C chemokine ligand 20 (CCL20) expression to promote chronic inflammation and airway remodeling in an HDM-induced bronchial asthma mouse model. We showed that HDM increased CCL20 levels via the Akt-ERK1/2-C/EBPβ pathway. To investigate the role of CCL20 in chronic airway inflammation and remodeling, we made a mouse model of CCL20-induced bronchial asthma. Treatment of anti-CCL20Ab in this mouse model showed the reduced airway hyper-responsiveness and inflammatory cell infiltration into peribronchial region by neutralizing CCL20. In addition, CCL20 induced the Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation through NLRP3 deubiquitination and transcriptional upregulation in BEAS-2B cells. As expected, anti-CCL20Ab markedly suppressed NLRP3 activation induced by CCL20. Moreover, HDM-induced CCL20 leads to epithelial-mesenchymal transition in the lung epithelium which appears to be an important regulator of airway remodeling in allergic asthma. We also found that anti-CCL20Ab attenuates airway inflammation and remodeling in an HDM-induced mouse model of bronchial asthma. Taken together, our results suggest that HDM-induced CCL20 is required for chronic inflammation that contributes airway remodeling in a mouse model of asthma.

HumanMine: advanced data searching, analysis and cross-species comparison

HumanMine (www.humanmine.org) is an integrated database of human genomics and proteomics data that provides a powerful interface to support sophisticated exploration and analysis of data compiled from experimental, computational and curated data sources. Built using the InterMine data integration platform, HumanMine includes genes, proteins, pathways, expression levels, Single nucleotide polymorphism (SNP), diseases and more, integrated into a single searchable database. HumanMine promotes integrative analysis, a powerful approach in modern biology that allows many sources of evidence to be analysed together. The data can be accessed through a user-friendly web interface as well as a powerful, scriptable web service Application programming interface (API) to allow programmatic access to data. The web interface includes a useful identifier resolution system, sophisticated query options and interactive results tables that enable powerful exploration of data, including data summaries, filtering, browsing and export. A set of graphical analysis tools provide a rich environment for data exploration including statistical enrichment of sets of genes or other biological entities. HumanMine can be used for integrative multistaged analysis that can lead to new insights and uncover previously unknown relationships.

Database URL: https://www.humanmine.org

Evaluation of IGF-1, TNF-α, and TGF-β Gene Expression after Oral Vitamin D Supplementation in School-Aged Children with Chronic Bronchial Asthma

BACKGROUND: Airway remodeling in children with bronchial asthma is due to the effect of inflammatory mediators and growth factors on the bronchial epithelium. Vitamin D (VitD) has immunomodulatory effect in many inflammatory diseases as bronchial asthma. The ant-inflammatory and anti-fibrotic role of VitD could prevent or improve air way remodeling in asthmatic patients. AIM: The study investigated the effect of VitD supplementation on the expression of transforming growth factor-beta (TGF-β), tumor necrosis factor-alpha (TNF-α), and insulin growth factor 1(IGF-1) and to correlate them with asthma severity and level of control. METHODS: The serum level of VitD and the mRNA expression of IGF-1, TGF-β, and TNF-α were estimated in 50 patients and 20 healthy controls control subjects using quantitative PCR in real-time. Asthmatic patients with VitD deficiency received VitD supplementation for 2 months followed by remeasurement of serum VitD and the genes expression TGF-β, TNF-α, and IGF-1. RESULT: Pre-intake of VitD and serum level of VitD were lower in all patients than control subjects (p = 0.005). VitD level was directly correlated with IGF-1 mRNA expression, which was indirectly correlated with TGF-β, r = 0.5 and −0.57; p = 0.0001 and 0.002, respectively. After VitD supplementation, the expression of the TGF-β mRNA gene was the only gene that decreased significantly (p = 0.04) together with improved asthma control and spirometric parameters. CONCLUSIONS: VitD supplementation down regulated the gene expression of TGF-β and improved asthma control level, but it did not significantly affect the gene expression of TNF-α and IGF-1.

Dioscin exhibits protective effects on in vivo and in vitro asthma models via suppressing TGF-β1/Smad2/3 and AKT pathways

Dioscin is a natural product that possesses protective effects on multiple chronic injuries, but its effects on asthma are not fully understood. Herein, we evaluated its effects on asthmatic mice established by ovalbumin (OVA) sensitization and challenges and further explored the mechanism. Inflammatory cells in bronchoalveolar lavage fluids (BALFs) were analyzed using Diff-Quik staining. OVA-specific immunoglobulin E (IgE)/IgG1 in serum and inflammatory cytokines (interleukin 4[IL-4], IL-5, IL-13, and tumor necrosis factor-α) in BALFs and lung tissues were measured using Enzyme-Linked Immunosorbent Assay Kits. Hematoxylin and eosin, periodic acid-Schiff, and immunohistochemistry staining showed histopathological changes in lung tissues. Epithelial-mesenchymal transition (EMT) in human bronchial epithelial (16HBE) cells was assessed by immunofluorescence staining. Hydroxyproline content was used to evaluate collagen deposition. Polymerase chain reaction and Western blot were performed to measure messenger RNA and protein expression. We found that dioscin treatment (particularly at the dose of 80 mg/kg) significantly inhibited pulmonary inflammation in asthmatic mice, as evidenced by the decreased serum OVA-specific IgE/IgG1 and the reduced inflammatory cells and cytokines in BALFs and lung tissues. Moreover, dioscin effectively ameliorated the goblet cell hyperplasia, mucus hypersecretion, collagen deposition, and smooth muscle hyperplasia in the airways of asthmatic mice. Mechanistically, dioscin restrained the activated TGF-β1/Smad2/3 and protein kinase B (AKT) signal pathways in lung tissues and potently reversed the TGF-β1-induced EMT and phosphorylation of Smad2/3 and AKT in 16HBE cells. Collectively, dioscin displayed protective effects on OVA-induced asthmatic mice via adjusting TGF-β1/Smad2/3 and AKT signal pathways, supporting the fact that dioscin could be a candidate for chronic asthma prevention in the future.

A Network Pharmacology Approach to Reveal the Underlying Mechanisms of Rhizoma Dioscoreae Nipponicae in the Treatment of Asthma

Background

In this study, network pharmacological methods were used to analyze the targets of Rhizoma Dioscoreae Nipponicae (RDN) and investigate the potential underlying mechanism of RDN in the treatment of asthma.

Methods

Asthma-related targets were obtained from the GeneCards and DisGeNET databases. The bioactive components of RDN were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database, and the targets of these compounds were predicted using the BATMAN-TCM database. The network of RDN component targets was constructed using Cytoscape. A protein-protein interaction (PPI) network was constructed in Cytoscape to determine the potential targets of RDN for the treatment of asthma. The hub genes of RDN in the treatment of asthma were screened using network topological parameters. Gene ontology (GO) and the KEGG pathways were analyzed. Molecular docking and in vivo experiments were performed to validate the network pharmacology results.

Results

A total of four bioactive components and 55 targets were identified. The results of the enrichment analysis suggested that the treatment of asthma with RDN involved signaling pathways, such as those related to systemic lupus erythematosus, alcoholism, viral carcinogenesis, the cell cycle, prostate cancer, transcriptional misregulation in cancer, hepatitis B, thyroid hormone signaling, and PI3K-AKT signaling, as well as other signaling pathways. Molecular docking showed that the active components of RDN could stably bind to the predicted target. In vivo experiments showed that RDN could regulate the expression of target genes and inhibit the activation of the PI3K-AKT signaling pathway.

Conclusion

To a certain extent, this study reveals the potential bioactive components and molecular mechanisms of RDN in the treatment of asthma and provides new insights for the development of new drugs for asthma.

Obesity and the Development of Lung Fibrosis

Obesity is an epidemic worldwide and the obese people suffer from a range of respiratory complications including fibrotic changes in the lung. The influence of obesity on the lung is multi-factorial, which is related to both mechanical injury and various inflammatory mediators produced by excessive adipose tissues, and infiltrated immune cells. Adiposity causes increased production of inflammatory mediators, for example, cytokines, chemokines, and adipokines, both locally and in the systemic circulation, thereby rendering susceptibility to respiratory diseases, and altered responses. Lung fibrosis is closely related to chronic inflammation in the lung. Current data suggest a link between lung fibrosis and diet-induced obesity, although the mechanism remains incomplete understood. This review summarizes findings on the association of lung fibrosis with obesity, highlights the role of several critical inflammatory mediators (e.g., TNF-α, TGF-β, and MCP-1) in obesity related lung fibrosis and the implication of obesity in the outcomes of idiopathic pulmonary fibrosis patients.

Beyond TGFβ1 - novel treatment strategies targeting lung fibrosis

Fibrosis is a key feature of chronic lung diseases and occurs as a consequence of aberrant wound healing. TGFβ1 plays a major role in promoting fibrosis and is the primary target of current treatments that slow, but do not halt or reverse the progression of disease. Accumulating evidence suggests that additional mechanisms, including excessive airway contraction, inflammation and infections including COVID-19, can contribute to fibrosis. This review summarises experimental and clinical studies assessing the potential beneficial effects of novel drugs that possess a unique suite of complementary actions to oppose contraction, inflammation and remodelling, along with evidence that they also limit fibrosis. Translation of these promising findings is critical for the repurposing and development of improved therapeutics for fibrotic lung diseases.

The nitroxide/antioxidant 3-carbamoyl proxyl attenuates disease severity in murine models of severe asthma

Asthma is characterized by airway inflammation, hyper-responsiveness, symptoms of dyspnea, wheezing and coughing. In most patients, asthma is well controlled using inhaled corticosteroids and bronchodilators. A minority of patients with asthma develop severe disease, which is frequently only partially responsive or even resistant to treatment with corticosteroids. Severe refractory asthma is associated with structural changes in the airways, termed "airway remodeling", and/or with neutrophilic rather than eosinophilic airway inflammation. While oxidative stress plays an important role in the pathophysiology of asthma, cyclic nitroxide stable radicals, which are unique and efficient catalytic antioxidants, effectively protect against oxidative injury. We have demonstrated that the nitroxide 3-carbamoyl proxyl (3-CP) attenuates airway inflammation and hyperresponsiveness in allergic asthma as well as bleomycin-induced fibrosis both using murine models, most probably through modulation of oxidative stress. The present study evaluates the effect of 3-CP on airway inflammation and remodeling using two murine models of severe asthma where mice are sensitized and challenged either by ovalbumin (OVA) or by house dust mite (HDM). 3-CP was orally administered during the entire period of the experiment or during the challenge period alone where its effect was compared to that of dexamethasone. The induced increase by OVA and by HDM of BALf cell counts, airway hyperresponsiveness, fibrosis, transforming growth factor-beta (TGF-β) levels in BALf and protein nitration levels of the lung tissue was significantly reduced by 3-CP. The effect of 3-CP, using two different murine models of severe asthma, is associated at least partially with attenuation of oxidative stress and with TGF-β expression in the lungs. The results of this study suggest a potential use of 3-CP as a novel therapeutic agent in different forms of severe asthma.

Urinary caffeine and caffeine metabolites, asthma, and lung function in a nationwide study of U.S. adults

OBJECTIVE

Coffee intake has been inversely associated with asthma in adults. We examined the relation between urinary levels of caffeine or caffeine metabolites and asthma, lung function, and fractional exhaled nitric oxide (FeNO) in adults.

METHODS

Cross-sectional study of 2,832 adults aged 18-79 years in the US National Health and Nutrition Examination Survey (NHANES). Multivariable logistic or linear regression was used for the analysis of urinary levels of caffeine or each of its three major metabolites (paraxanthine, theobromine, and theophylline) and current asthma, lung function, and FeNO.

RESULTS

Subjects with urinary paraxanthine levels in the fourth quartile (Q4) had 53% lower odds of current asthma than those whose urinary paraxanthine levels were in the first quartile (Q1; 95% confidence = 0.22 to 1.00). Among never and former smokers, subjects with urinary theophylline levels above Q1 had 49% lower odds of current asthma than those whose urinary theophylline level was in Q1 (95% CI = 0.31 to 0.85). Among subjects without current asthma, each log₁₀-unit increment in paraxanthine level was associated with a 0.83% increment in percent predicted (%pred) FEV₁ and a 1.27% increment in %pred FVC, while each log₁₀-unit in theophylline was associated with a 1.24% increment in %pred FVC. Neither urinary caffeine nor any urinary caffeine metabolite was associated with bronchodilator response or FeNO.

CONCLUSIONS

Our findings suggest that two caffeine metabolites (theophylline and paraxanthine) may contribute to the previously reported inverse association between coffee intake and asthma in adults.

Synthesis and in vitro evaluation of anti-inflammatory, antioxidant, and anti-fibrotic effects of new 8-aminopurine-2,6-dione-based phosphodiesterase inhibitors as promising anti-asthmatic agents

Phosphodiesterase (PDE) inhibitors are currently an extensively studied group of compounds that can bring many benefits in the treatment of various inflammatory and fibrotic diseases, including asthma. Herein, we describe a series of novel N'-phenyl- or N'-benzylbutanamide and N'-arylidenebutanehydrazide derivatives of 8-aminopurine-2,6-dione (27-43) and characterized them as prominent pan-PDE inhibitors. Most of the compounds exhibited antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)-induced murine macrophages RAW264.7. The most active compounds (32-35 and 38) were evaluated in human bronchial epithelial cells (HBECs) derived from asthmatics. To better map the bronchial microenvironment in asthma, HBECs after exposure to selected 8-aminopurine-2,6-dione derivatives were incubated in the presence of two proinflammatory and/or profibrotic factors: transforming growth factor type β (TGF-β) and interleukin 13 (IL-13). Compounds 32-35 and 38 significantly reduced both IL-13- and TGF-β-induced expression of proinflammatory and profibrotic mediators, respectively. Detailed analysis of their inhibition preferences for selected PDEs showed high affinity for isoenzymes important in the pathogenesis of asthma, including PDE1, PDE3, PDE4, PDE7, and PDE8. The presented data confirm that structural modifications within the 7 and 8 positions of the purine-2,6-dione core result in obtaining preferable pan-PDE inhibitors which in turn exert an excellent anti-inflammatory and anti-fibrotic effect in the bronchial epithelial cells derived from asthmatic patients. This dual-acting pan-PDE inhibitors constitute interesting and promising lead structures for further anti-asthmatic agent discovery.

Effect of TGF-β1 on eosinophils to induce cysteinyl leukotriene E4 production in aspirin-exacerbated respiratory disease

Cysteinyl leukotriene (cysLT) overproduction and eosinophil activation are hallmarks of aspirin-exacerbated respiratory disease (AERD). However, pathogenic mechanisms of AERD remain to be clarified. Here, we aimed to find the significance of transforming growth factor beta 1 (TGF-β1) in association with cysteinyl leukotriene E4 (LTE4) production, leading to eosinophil degranulation. To evaluate levels of serum TGF-β1, first cohort enrolled AERD (n = 336), ATA (n = 442) patients and healthy control subjects (HCs, n = 253). In addition, second cohort recruited AERD (n = 34) and ATA (n = 25) patients to investigate a relation between levels of serum TGF-β1 and urinary LTE4. The function of TGF-β1 in LTE4 production was further demonstrated by ex vivo (human peripheral eosinophils) or in vivo (BALB/c mice) experiment. As a result, the levels of serum TGF-β1 were significantly higher in AERD patients than in ATA patients or HCs (P = .001; respectively). Moreover, levels of serum TGF-β1 and urinary LTE4 had a positive correlation (r = 0.273, P = .037). In the presence of TGF-β1, leukotriene C4 synthase (LTC4S) expression was enhanced in peripheral eosinophils to produce LTE4, which sequentially induced eosinophil degranulation via the p38 pathway. When mice were treated with TGF-β1, significantly induced eosinophilia with increased LTE4 production in the lung tissues were noted. These findings suggest that higher levels of TGF-β1 in AERD patients may contribute to LTE4 production via enhancing LTC4S expression which induces eosinophil degranulation, accelerating airway inflammation.

Contribution of dipeptidyl peptidase 10 to airway dysfunction in patients with NSAID-exacerbated respiratory disease

BACKGROUND

Genetic variants of dipeptidyl peptidase 10 (DPP10) have been suggested to contribute to the development of NSAID-exacerbated respiratory disease (NERD). However, the mechanisms of how DPP10 contributes to NERD phenotypes remain unclear.

OBJECTIVE

To demonstrate the exact role of DPP10 in the pathogenesis of NERD.

METHODS

Patients with NERD (n = 110), those with aspirin-tolerant asthma (ATA, n = 130) and healthy control subjects (HCs, n = 80) were enrolled. Clinical characteristics were analysed according to the serum DPP10 levels in both NERD and ATA groups. The function of DPP10 in airway inflammation and remodelling was investigated with in vitro, ex vivo and in vivo experiments.

RESULTS

NERD patients had higher levels of serum DPP10 and TGF-β1 with lower FEV₁ than ATA patients or HCs (p < .05 for each). NERD patients with higher DPP10 levels had higher TGF-β1, but lower FEV₁ (p < .05 for all), whilst no differences were noted in ATA patients. Moreover, the seum DPP10 levels had a positive correlation with TGF-β1 (r = 0.384, p < .001), but a negative correlation with FEV₁ (r = -0.230, p = .016) in NERD patients. In in vitro studies, expression of DPP10 in airway epithelial cells was enhanced by TGF-β1 treatments. Furthermore, DPP10 was found to be produced from immune cells and this molecule induced the ERK phosphorylation in airway epithelial cells, which was suppressed by anti-DPP10 treatment. In asthmatic mouse models, increased levels of DPP10 in the serum and TGF-β1 in the bronchoalveolar lavage fluid were noted, which were suppressed by anti-DPP10 treatment. Moreover, anti-DPP10 treatment inhibited the ERK phosphorylation and extracellular matrix deposition in the lungs.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings suggest that increased production of DPP10 may contribute to TGF-β1-mediated airway dysfunction in NERD patients, where blockade of DPP10 may have potential benefits.

Epigenetic programming underpins B-cell dysfunction in peanut and multi-food allergy

OBJECTIVE

Rates of IgE-mediated food allergy (FA) have increased over the last few decades, and mounting evidence implicates disruption of epigenetic profiles in various immune cell types in FA development. Recent data implicate B-cell dysfunction in FA; however, few studies have examined epigenetic changes within these cells.

METHODS

We assessed epigenetic and transcriptomic profiles in purified B cells from adolescents with FA, comparing single-food-allergic (peanut only), multi-food-allergic (peanut and ≥1 other food) and non-allergic (control) individuals. Adolescents represent a phenotype of persistent and severe FA indicative of a common immune deviation.

RESULTS

We identified 144 differentially methylated probes (DMPs) and 116 differentially expressed genes (DEGs) that distinguish B cells of individuals with FA from controls, including differential methylation of the PM20D1 promoter previously associated with allergic disorders. Subgroup comparisons found 729 DMPs specific to either single-food- or multi-food-allergic individuals, suggesting epigenetic distinctions between allergy groups. This included two regions with increased methylation near three S100 genes in multi-food-allergic individuals. Ontology results of DEGs specific to multi-food-allergic individuals revealed enrichment of terms associated with myeloid cell activation. Motif enrichment analysis of promoters associated with DMPs and DEGs showed differential enrichment for motifs recognised by transcription factors regulating B- and T-cell development, B-cell lineage determination and TGF-β signalling pathway between the multi-food-allergic and single-food-allergic groups.

CONCLUSION

Our data highlight epigenetic changes in B cells associated with peanut allergy, distinguishing features of the epigenome between single-food- and multi-food-allergic individuals and revealing differential developmental pathways potentially underpinning these distinct phenotypes.

Asthmatic Eosinophils Promote Contractility and Migration of Airway Smooth Muscle Cells and Pulmonary Fibroblasts In Vitro

Enhanced contractility and migration of airway smooth muscle cells (ASMC) and pulmonary fibroblasts (PF) are part of airway remodeling in asthma. Eosinophils are the central inflammatory cells that participate in airway inflammation. However, the role of asthmatic eosinophils in ASMC and PF contractility, migration, and differentiation to contractile phenotype has not yet been precisely described. A total of 38 individuals were included in this study: 13 steroid-free non-severe allergic asthma (AA) patients, 11 severe non-allergic eosinophilic asthma (SNEA) patients, and 14 healthy subjects (HS). For AA patients and HS groups, a bronchial allergen challenge with D. pteronyssinus was performed. Individual combined cell cultures were prepared from isolated peripheral blood eosinophils and immortalized ASMC or commercial PF cell lines separately. The migration of ASMC and PF was evaluated using wound healing assay and contractility using collagen gel assay. Gene expression of contractile apparatus proteins, COL1A1, COL5A1, and FN, in ASMC and PF was evaluated using qRT-PCR. We found that contractility and migration of ASMC and PF significantly increased after incubation with asthmatic eosinophils compared to HS eosinophils, p < 0.05, and SNEA eosinophils demonstrated the highest effect on contractility of ASMC and migration of both cell lines, p < 0.05. AA and SNEA eosinophils significantly increased gene expression of contractile apparatus proteins, COL1A1 and FN, in both cell lines, p < 0.05. Furthermore, the allergen-activated AA eosinophils significantly increased the contractility of ASMC, and migration and gene expression in ASMC and PF, p < 0.05. Thus, asthmatic eosinophils change ASMC and PF behavior by increasing their contractility and migration, contributing to airway remodeling.

Biomarkers for Severe Asthma: Lessons From Longitudinal Cohort Studies

Severe asthma (SA) is a heterogeneous disease characterized by uncontrolled symptoms, frequent exacerbations, and lung function decline. The discovery of phenotypes and endotypes of SA significantly improves our understanding of its pathophysiology and allows the advent of biologics blocking multiple molecular targets. The advances have mainly been made in type 2-high asthma associated with elevated type 2 inflammatory biomarkers such as immunoglobulin E (IgE), interleukins (IL)-4, IL-5, and IL-13. Previous clinical trials have demonstrated that type 2 biomarkers, including blood/sputum eosinophils and the fraction of exhaled nitric oxide (FeNO), were correlated to severe airway inflammation, persistent symptoms, frequent exacerbations, and the clinical efficacy of these biomarkers in predicting treatment outcomes of type 2-targeting biologics. However, it is well known that type 2 inflammation is partially attributable to the pathogenesis of SA. Although some recent studies have suggested that type 2-low and mixed phenotypes of asthma are important contributors to the heterogeneity of SA, many questions about these non-type 2 asthma phenotypes remain to be solved. Consequently, many efforts to investigate and find novel biomarkers for SA have also made in their methods. Many cross-sectional experimental studies in large-scale cohorts and randomized clinical trials have proved their value in understanding SA. More recently, real-world cohort studies have been in the limelight for SA research, which is unbiased and expected to give us an answer to the unmet needs of the heterogeneity of SA.

Reduced biomechanical models for precision-cut lung-slice stretching experiments

Precision-cut lung-slices (PCLS), in which viable airways embedded within lung parenchyma are stretched or induced to contract, are a widely used ex vivo assay to investigate bronchoconstriction and, more recently, mechanical activation of pro-remodelling cytokines in asthmatic airways. We develop a nonlinear fibre-reinforced biomechanical model accounting for smooth muscle contraction and extracellular matrix strain-stiffening. Through numerical simulation, we describe the stresses and contractile responses of an airway within a PCLS of finite thickness, exposing the importance of smooth muscle contraction on the local stress state within the airway. We then consider two simplifying limits of the model (a membrane representation and an asymptotic reduction in the thin-PCLS-limit), that permit analytical progress. Comparison against numerical solution of the full problem shows that the asymptotic reduction successfully captures the key elements of the full model behaviour. The more tractable reduced model that we develop is suitable to be employed in investigations to elucidate the time-dependent feedback mechanisms linking airway mechanics and cytokine activation in asthma.

Pilot study investigating diagnostic utility of serum MMP-1 and TGF-β1 in asthma in 'real world' clinical practice in India

AIMS

At a tissue level, matrix metalloproteinase-1 (MMP-1) and transforming growth factor-beta 1 (TGF-β1) contribute to allergic airway inflammation, tissue remodelling and disease severity in asthma via different pathways. Their peripheral blood levels and role in diagnosis and therapeutic monitoring has not been adequately explored. We investigated the association between MMP-1 and TGF-β in moderate and severe persistent asthma and evaluated their performance characteristics by constructing receiver operating characteristic curves.

METHODS

Serum MMP-1 and TGF-β1 were measured using ELISA in 75 adults; moderate persistent asthma (n=25), severe persistent asthma (n=25) and healthy community controls (n=25). Severity of asthma was determined as per Global Initiative for Asthma guidelines. Subjects were followed up for 3 months and treatment responsiveness was assessed by spirometry and symptom response.

RESULTS

Serum MMP-1 and TGF-β1 were significantly elevated in asthmatics compared with controls (p<0.0001 and p<0.01). While serum MMP-1 was elevated in severe asthma compared with moderate asthma (p<0.05), TGF-β1 was lower in severe asthma compared with moderate asthma (p<0.05). The performance characteristics of serum MMP-1 and TGF-β1 were promising in this cohort with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 82%, 100%, 100% and 99% and 62%, 100%, 100% and 97.8%, respectively; sensitivity of MMP-1 being superior.

CONCLUSION

This pilot study showed that serum MMP-1 and TGF-β1 levels are elevated in chronic asthma and may serve as a useful adjunct in differentiating moderate from severe asthma. A large multicentre study in well characterised cohort of asthmatics is warranted to investigate their role in diagnosis and therapeutic monitoring.

AITC inhibits fibroblast-myofibroblast transition via TRPA1-independent MAPK and NRF2/HO-1 pathways and reverses corticosteroids insensitivity in human lung fibroblasts

Background

Little is known on the role of transient receptor potential ankyrin 1 (TRPA1) in fibroblast—myofibroblast transition (FMT) that can lead to airway remodeling which is a major problem for severe asthma and fibrosis. Thus, this study investigated the effect of TRPA1 modulators on transforming growth factor beta 1(TGF-β1) -treated lung fibroblasts.

Methods

MRC-5 cells were preincubated with TGF-β1 for 24 h. TRPA1 agonist or antagonist were added and further incubated for 24 h. The changes in TRPA1 and alpha-smooth muscle actin (α-SMA) expressions by stimuli were evaluated using qRT-PCR, western blot and immunohistochemical analyses. Statistical significance was determined by using one- or two-way ANOVA, followed by Bonferroni’s post hoc analysis for comparison of multiple groups and paired 2-tailed Student’s t-test between 2 groups.

Results

MRC-5 cells treated by TGF-β1 significantly upregulated α-SMA mRNA expressions (P < 0.01), but downregulated TRPA1 gene expression (P < 0.001). Post-treatment of TRPA1 activator, allyl isothiocyanate (AITC), after TGF-β1 significantly downregulated the α-SMA gene induction (P < 0.01 at 24 h), protein expression (P < 0.05) and immunoreactivity with stress fibers (P < 0.05). On the other hand, TRPA1 antagonist HC-030031 did not prevent this effect, and instead tended to facilitate the suppressive effect of AITC when co-stimulated. AITC significantly increased phosphorylated- extracellular signal-regulated kinase (ERK) 1/2 and heme oxygenase (HO)-1 protein expressions (P < 0.05) in TGF-β1-treated cells. Combined inhibition with ERK1/2 mitogen-activated protein kinase (MAPK) and nuclear factor erythroid 2-related factor (NRF2) almost completely reversed AITC-induced α-SMA suppression (P < 0.05). Dexamethasone was not able to inhibit the upregulated α-SMA induction by TGF-β1. However, AITC improved dexamethasone-insensitive myodifferentiation in the presence of the corticosteroid (P < 0.01).

Conclusion

We found that AITC exerts protective effect on TGF-β1-induced α-SMA induction by activating ERK1/2 MAPK and NRF2/HO-1 pathways in lung fibroblasts. It also overcomes corticosteroids insensitivity in TGF-β1-induced α-SMA induction. TRPA1 antagonist modulates the suppressive effect, but not prevent it. AITC and TRPA1 antagonist may be therapeutic agents in treating chronic respiratory diseases.

TGF-β: The missing link in obesity-associated airway diseases?

Obesity is emerging as a global public health epidemic. The co-morbidities associated with obesity significantly contribute to reduced quality of life, mortality, and global healthcare burden. Compared to other asthma comorbidities, obesity prominently engenders susceptibility to inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), contributes to greater disease severity and evokes insensitivity to current therapies. Unlike in other metabolic diseases associated with obesity, the mechanistic link between obesity and airway diseases is only poorly defined. Transforming growth factor-β (TGF-β) is a pleiotropic inflammatory cytokine belonging to a family of growth factors with pivotal roles in asthma. In this review, we summarize the role of TGF-β in major obesity-associated co-morbidities to shed light on mechanisms of the diseases. Literature evidence shows that TGF-β mechanistically links many co-morbidities with obesity through its profibrotic, remodeling, and proinflammatory functions. We posit that TGF-β plays a similar mechanistic role in obesity-associated inflammatory airway diseases such as asthma and COPD. Concerning the role of TGF-β on metabolic effects of obesity, we posit that TGF-β has a similar mechanistic role in obesity-associated inflammatory airway diseases in interplay with different comorbidities such as hypertension, metabolic diseases like type 2 diabetes, and cardiomyopathies. Future studies in TGF-β-dependent mechanisms in obesity-associated inflammatory airway diseases will advance our understanding of obesity-induced asthma and help find novel therapeutic targets for prevention and treatment.

Targeted inhibition of β-catenin alleviates airway inflammation and remodeling in asthma via modulating the profibrotic and anti-inflammatory actions of transforming growth factor-β1

Background:

TGF-β₁ is a key cytokine involved in both airway inflammation and airway remodeling in asthma because of its anti-inflammatory and profibrotic effect. In our previous study, we found that knockdown of cytosolic β-catenin alleviated the profibrogenic effect of TGF-β₁ without influencing its anti-inflammatory effect. However, the exact role of targeting β-catenin in asthma is not yet fully demonstrated. In the present study, we investigated the effect and mechanism of targeting β-catenin in OVA-challenged asthmatic rats with airway inflammation and remodeling features.

Methods:

We integrated experimental asthma model and asthma related cell model to explore the effect of targeting β-catenin on airway inflammation and remodeling of asthma.

Results:

Blocking β-catenin with ICG001, a small molecule inhibitor of β-catenin/TCF via binding to cAMP-response elementbinding protein, attenuated airway inflammation by increasing levels of anti-inflammation cytokines IL-10, IL-35 and decreasing levels of T helper (Th)2 cells and Th17 cytokine. Suppressing β-catenin by ICG001 inhibited airway remodeling via reducing the level of TGF-β₁ and the expressions of Snail, MMP-7, MMP-9 and, up-regulating expression of E-cadherin, down-regulating expressions of α-SMA and Fn. Inhibition of β-catenin with ICG001 suppressed TGF-β₁ induced proliferation and activation of CCC-REPF-1, blocked TGF-β₁ induced epithelial–mesenchymal transition (EMT) of RLE-6TN.

Conclusion:

Blockade of β-catenin/TCF not only prevents TGF-β₁ induced EMT and profibrogenic effects involved in pathological remodeling of airway, but also alleviates airway inflammation in asthma by balancing pro-inflammatory and anti-inflammatory cytokine. In conclusion, targeting β-catenin specifically via inhibition of β-catenin/TCF might be a new therapeutic strategy for asthma.

The reviews of this paper are available via the supplemental material section.

Structure and function of small airways in asthma patients revisited

Small airways (<2 mm in diameter) are probably involved across almost all asthma severities and they show proportionally more structural and functional abnormalities with increasing asthma severity. The structural and functional alterations of the epithelium, extracellular matrix and airway smooth muscle in small airways of people with asthma have been described over many years using in vitro studies, animal models or imaging and modelling methods. The purpose of this review was to provide an overview of these observations and to outline several potential pathophysiological mechanisms regarding the role of small airways in asthma.

Hypoxic hUCMSC-derived extracellular vesicles attenuate allergic airway inflammation and airway remodeling in chronic asthma mice

BACKGROUND

As one of the main functional forms of mesenchymal stem cells (MSCs), MSC-derived extracellular vesicles (MSC-EVs) have shown an alternative therapeutic option in experimental models of allergic asthma. Oxygen concentration plays an important role in the self-renewal, proliferation, and EV release of MSCs and a recent study found that the anti-asthma effect of MSCs was enhanced by culture in hypoxic conditions. However, the potential of hypoxic MSC-derived EVs (Hypo-EVs) in asthma is still unknown.

METHODS

BALB/c female mice were sensitized and challenged with ovalbumin (OVA), and each group received PBS, normoxic human umbilical cord MSC-EVs (Nor-EVs), or Hypo-EVs weekly. After treatment, the animals were euthanized, and their lungs and bronchoalveolar lavage fluid (BALF) were collected. With the use of hematoxylin and eosin (HE), periodic acid-Schiff (PAS) and Masson's trichrome staining, enzyme-linked immune sorbent assay (ELISA), Western blot analysis, and real-time PCR, the inflammation and collagen fiber content of airways and lung parenchyma were investigated.

RESULTS

Hypoxic environment can promote human umbilical cord MSCs (hUCMSCs) to release more EVs. In OVA animals, the administration of Nor-EVs or Hypo-EVs significantly ameliorated the BALF total cells, eosinophils, and pro-inflammatory mediators (IL-4 and IL-13) in asthmatic mice. Moreover, Hypo-EVs were generally more potent than Nor-EVs in suppressing airway inflammation in asthmatic mice. Compared with Nor-EVs, Hypo-EVs further prevented mouse chronic allergic airway remodeling, concomitant with the decreased expression of pro-fibrogenic markers α-smooth muscle actin (α-SMA), collagen-1, and TGF-β1-p-smad2/3 signaling pathway. In vitro, Hypo-EVs decreased the expression of p-smad2/3, α-SMA, and collagen-1 in HLF-1 cells (human lung fibroblasts) stimulated by TGF-β1. In addition, we showed that miR-146a-5p was enriched in Hypo-EVs compared with that in Nor-EVs, and Hypo-EV administration unregulated the miR-146a-5p expression both in asthma mice lung tissues and in TGF-β1-treated HLF-1. More importantly, decreased miR-146a-5p expression in Hypo-EVs impaired Hypo-EV-mediated lung protection in OVA mice.

CONCLUSION

Our findings provided the first evidence that hypoxic hUCMSC-derived EVs attenuated allergic airway inflammation and airway remodeling in chronic asthma mice, potentially creating new avenues for the treatment of asthma.

Cysteinyl leukotriene D4 (LTD4) promotes airway epithelial cell inflammation and remodelling

OBJECTIVE

Cysteinyl leukotrienes (CysLTs), a group of inflammatory lipid mediators, are found elevated in obese-asthmatic patients. Leukotriene D4 (LTD4), a representative CysLT, is implicated in promoting lung inflammation and remodelling in allergic asthma, but its role in non-allergic asthma, especially in obese-asthmatic patients, is not known. Here, using primary human small airway epithelial cells (SAECs) we have investigated the mechanism of LTD4-induced inflammation and remodelling and assessed high proneness of obese mice to develop asthma upon challenge with allergen ovalbumin (OVA).

METHODS

Primary human small airway epithelial cells (SAECs) were stimulated with different concentrations of LTD4 for different time intervals and various inflammatory markers were measured through cytokine array, membrane-based ELISA and Western blotting. An air-liquid interface (ALI) model of SAECs was used to study the effects of LTD4-induced remodelling in SAECs using Western blotting, H&E staining and PAS staining. Further, OVA-based murine model was used to examine the propensity of high-fat diet (HFD)-fed obese mice to develop asthma symptoms by studying the infiltration of inflammatory cells (assessed by bronchioalveolar lavage (BAL) cytology) and airway remodelling (assessed by histopathology) upon allergen exposure.

RESULTS

The human primary small airway epithelial cells (SAECs) treated with LTD4 showed significant alterations in the levels of inflammatory markers such as GM-CSF, TNF-α, IL-1β, EGF and eotaxin in dose- and time-dependent manner. Further, LTD4 enhanced the activation of inflammasomes as evidenced by increased levels of NALP3, cleaved caspase-1 and IL-1β. LTD4 also enhanced inflammation by increasing the expression of COX-2 in SAECs. The airway remodelling markers Vimentin and Muc5AC were found elevated in ALI culture of SAECs when stimulated with LTD4, as it also increased TGF-β levels and activation of Smad2/3 phosphorylation in SAECs. Last, sensitization and challenge of HFD-fed obese mice with OVA showed increased infiltration of inflammatory cells in BAL and enhanced levels of remodeling phenotypes like loss of cilia, mucus cell metaplasia and collagen deposition in mice lung tissues.

CONCLUSION

The results suggest that LTD4 could induce inflammatory response in human airway epithelial cell by activating NALP3 inflammasome. LTD4 could further promote airway epithelial cells' remodelling through TGF-β/smad2/3-mediated pathway. Our in vivo results suggested that obesity predisposed the OVA challenged mice to develop lung inflammation and remodelling akin to asthma-like phenotypes during obesity.

Mechanical and Physical Regulation of Fibroblast-Myofibroblast Transition: From Cellular Mechanoresponse to Tissue Pathology

Fibroblasts are cells present throughout the human body that are primarily responsible for the production and maintenance of the extracellular matrix (ECM) within the tissues. They have the capability to modify the mechanical properties of the ECM within the tissue and transition into myofibroblasts, a cell type that is associated with the development of fibrotic tissue through an acute increase of cell density and protein deposition. This transition from fibroblast to myofibroblast-a well-known cellular hallmark of the pathological state of tissues-and the environmental stimuli that can induce this transition have received a lot of attention, for example in the contexts of asthma and cardiac fibrosis. Recent efforts in understanding how cells sense their physical environment at the micro- and nano-scales have ushered in a new appreciation that the substrates on which the cells adhere provide not only passive influence, but also active stimulus that can affect fibroblast activation. These studies suggest that mechanical interactions at the cell-substrate interface play a key role in regulating this phenotype transition by changing the mechanical and morphological properties of the cells. Here, we briefly summarize the reported chemical and physical cues regulating fibroblast phenotype. We then argue that a better understanding of how cells mechanically interact with the substrate (mechanosensing) and how this influences cell behaviors (mechanotransduction) using well-defined platforms that decouple the physical stimuli from the chemical ones can provide a powerful tool to control the balance between physiological tissue regeneration and pathological fibrotic response.

The Utility of Resolving Asthma Molecular Signatures Using Tissue-Specific Transcriptome Data

An integrative analysis focused on multi-tissue transcriptomics has not been done for asthma. Tissue-specific DEGs remain undetected in many multi-tissue analyses, which influences identification of disease-relevant pathways and potential drug candidates. Transcriptome data from 609 cases and 196 controls, generated using airway epithelium, bronchial, nasal, airway macrophages, distal lung fibroblasts, proximal lung fibroblasts, CD4+ lymphocytes, CD8+ lymphocytes from whole blood and induced sputum samples, were retrieved from Gene Expression Omnibus (GEO). Differentially regulated asthma-relevant genes identified from each sample type were used to identify (a) tissue-specific and tissue-shared asthma pathways, (b) their connection to GWAS-identified disease genes to identify candidate tissue for functional studies, (c) to select surrogate sample for invasive tissues, and finally (d) to identify potential drug candidates via connectivity map analysis. We found that inter-tissue similarity in gene expression was more pronounced at pathway/functional level than at gene level with highest similarity between bronchial epithelial cells and lung fibroblasts, and lowest between airway epithelium and whole blood samples. Although public-domain gene expression data are limited by inadequately annotated per-sample demographic and clinical information which limited the analysis, our tissue-resolved analysis clearly demonstrated relative importance of unique and shared asthma pathways, At the pathway level, IL-1b signaling and ERK signaling were significant in many tissue types, while Insulin-like growth factor and TGF-beta signaling were relevant in only airway epithelial tissue. IL-12 (in macrophages) and Immunoglobulin signaling (in lymphocytes) and chemokines (in nasal epithelium) were the highest expressed pathways. Overall, the IL-1 signaling genes (inflammatory) were relevant in the airway compartment, while pro-Th2 genes including IL-13 and STAT6 were more relevant in fibroblasts, lymphocytes, macrophages and bronchial biopsies. These genes were also associated with asthma in the GWAS catalog. Support Vector Machine showed that DEGs based on macrophages and epithelial cells have the highest and lowest discriminatory accuracy, respectively. Drug (entinostat, BMS-345541) and genetic perturbagens (KLF6, BCL10, INFB1 and BAMBI) negatively connected to disease at multi-tissue level could potentially repurposed for treating asthma. Collectively, our study indicates that the DEGs, perturbagens and disease are connected differentially depending on tissue/cell types. While most of the existing literature describes asthma transcriptome data from individual sample types, the present work demonstrates the utility of multi-tissue transcriptome data. Future studies should focus on collecting transcriptomic data from multiple tissues, age and race groups, genetic background, disease subtypes and on the availability of better-annotated data in the public domain.

The anti-asthmatic potential of flavonol kaempferol in an experimental model of allergic airway inflammation

Flavonol kaempferol possesses a broad spectrum of potent pharmacological activities that seem to be effective in the modulation of allergic respiratory diseases. In our study, an experimental animal model of ovalbumin (OVA)-induced allergic airway inflammation in guinea pigs was used to determine the anti-asthmatic potential of kaempferol. The parameters of specific airway resistance (sRaw) and cough reflex response were evaluated in vivo. In vitro, an assessment of tracheal smooth muscle (TSM) contractility and analyses of inflammatory cytokines (IL-4, IL-5, IL-13, GM-CSF, IFN-γ), transforming growth factor (TGF-β1), immune cells count and ciliary beating frequency (CBF) were performed. Both single (6, 20 mg/kg b. w. p. o.) and long-term administered doses of kaempferol (20 mg/kg b. w. p. o., 21 days) suppressed sRaw provoked by histamine in conscious animals. The administration of kaempferol for 21 days attenuated histamine-induced TSM contractility in vitro and ameliorated the progression of chronic airway inflammation by decreasing the levels of IL-5, IL-13, GM-CSF, eosinophil count in bronchoalveolar lavage (BAL) fluid and TGF-β1 protein level in lung tissue. Kaempferol also eliminated the alterations in cough reflex sensitivity invoked by OVA-sensitization, but it did not affect CBF. The results demonstrate that flavonol kaempferol can modulate allergic airway inflammation and associated asthma features (AHR, aberrant stimulation of cough reflex).

An Integrative miRNA-mRNA Expression Analysis Reveals Striking Transcriptomic Similarities between Severe Equine Asthma and Specific Asthma Endotypes in Humans

Severe equine asthma is an incurable obstructive respiratory condition affecting 10–15% of horses in temperate climates. Upon exposure to airborne antigens from hay feeding, affected horses show neutrophilic airway inflammation and bronchoconstriction, leading to increased respiratory effort. The resulting implications range from welfare concerns to economic impacts on equestrian sports and horse breeding. Immunological and pathophysiological characteristics of severe equine asthma show important parallels with allergic and severe neutrophilic human asthma. Our study aimed at investigating regulatory networks underlying the pathophysiology of the disease by profiling miRNA and mRNA expression in lung tissue samples from asthmatic horses compared with healthy controls. We sequenced small RNAs and mRNAs from lungs of seven asthmatic horses in exacerbation, five affected horses in remission, and eight healthy control horses. Our comprehensive differential expression analyses, combined with the miRNA–mRNA negative correlation approach, revealed a strong similarity on the transcriptomic level between severe equine asthma and severe neutrophilic asthma in humans, potentially through affecting Th17 cell differentiation. This study also showed that several dysregulated miRNAs and mRNAs are involved in airway remodeling. These results present a starting point for a better transcriptomic understanding of severe equine asthma and its similarities to asthma in humans.