Remodeling in asthma

Role of IL-5 in asthma and airway remodelling

Asthma is a common and burdensome chronic inflammatory airway disease that affects both children and adults. One of the main concerns with asthma is the manifestation of irreversible tissue remodelling of the airways due to the chronic inflammatory environment that eventually disrupts the whole structure of the airways. Most people with troublesome asthma are treated with inhaled corticosteroids. However, the development of steroid resistance is a commonly encountered issue, necessitating other treatment options for these patients. Biological therapies are a promising therapeutic approach for people with steroid-resistant asthma. Interleukin 5 is recently gaining a lot of attention as a biological target relevant to the tissue remodelling process. Since IL-5-neutralizing monoclonal antibodies (mepolizumab, reslizumab and benralizumab) are currently available for clinical use, this review aims to revisit the role of IL-5 in asthma pathogenesis at large and airway remodelling in particular, in addition to exploring its role as a target for biological treatments.

Clarithromycin attenuates airway epithelial-mesenchymal transition in ovalbumin-induced asthmatic mice through modulation of Kv1.3 channels and PI3K/Akt signaling

Airway epithelial-mesenchymal transition (EMT) is the important pathological feature of airway remodeling in asthma. While macrolides are not commonly used to treat asthma, they have been shown to have protective effects on the airways, in which mechanisms are not yet fully understood. This study aims to investigate the impact of clarithromycin on airway EMT in asthma and its potential mechanism. The results revealed an increase in Kv1.3 expression in the airways of ovalbumin (OVA)-induced asthmatic mice, with symptoms and pathological changes being alleviated after treatment with the Kv1.3 inhibitor 5-(4-phenoxybutoxy)psoralen (PAP-1). Clarithromycin was found to attenuate airway epithelial-mesenchymal transition through the inhibition of Kv1.3 and PI3K/Akt signaling. Further experiments in vitro confirmed that PAP-1 could mitigate EMT by modulating the PI3K/Akt signaling in airway epithelial cells undergoing transformation into mesenchymal cells. These findings confirmed that clarithromycin might have a certain protective effect on asthma-related airway remodeling and represent a promising treatment strategy.

Radical S-adenosyl methionine domain-containing 2, a potential target of D-tryptophan in asthma treatment, regulates T helper cell type 1/2 balance

Asthma is a common chronic respiratory disease. D-tryptophan (D-TRP) can inhibit allergic airway inflammation and T helper cell type 2 (Th2) immune response. RNA-sequencing results have indicated that radical S-adenosyl methionine domain-containing 2 (RSAD2) might be a potential molecular target of D-TRP in asthma treatment. Herein, we established a mouse model of asthma using ovalbumin (OVA) via intraperitoneal injection and inhalational challenge. Gain- and loss-of-function studies of RSAD2 were performed in mice following the intratracheal delivery of lentiviral vectors (3 × 106 TU/mL). Naïve CD-4+ T cells were isolated from the spleen and used to explore the effects of RSAD2 on Th2 cell differentiation. RSAD2 expression was higher in the asthma group than in the control group. RSAD2 knockdown alleviated inflammatory cell infiltration and reduced the number of goblet cells. Low RSAD2 expression decreased the levels of IgE, IL-25, IL-33, and TSLP, and it reduced the number of inflammatory cells in the bronchoalveolar lavage fluid. RSAD2 silencing suppressed Th2-related cytokine levels (such as IL-4, IL-5, and IL-13) and increased Th1-related cytokine levels (such as IFN-γ). Additionally, RSAD2 knockdown inhibited the phosphorylation of JAK1, JAK3, and STAT6, and downregulated GATA-3 expression. RSAD2 overexpression increased inflammatory cell infiltration and mucus secretion in the lung tissues of mice pretreated with D-TRP. D-TRP pretreatment reduced OVA-specific IgE content and IL-4 and IL-5 levels, and it increased the IFN-γ levels; however, RSAD2 overexpression reversed these effects. In conclusion, RSAD2 knockdown can mitigate OVA-induced asthma by regulating the Th2 immune response via JAK/STAT6 pathway inhibition.

Myeloid Bmal1 deletion suppresses the house dust mite-induced chronic lung allergy

Asthma is the chronic pulmonary inflammatory response that could lead to respiratory failure when allergic reactions exacerbate. It is featured by type 2 immunity with eosinophilic inflammation, mucus, and IgE production, and Th2 cytokine secretion upon repeated challenge of allergens. The symptom severity of asthma displays an apparent circadian rhythm with aggravated airway resistance in the early morning in patients. Bmal1 is the core regulator of the circadian clock, while the regulatory role of Bmal1 in asthma remains unclear. Here, we investigate whether the myeloid Bmal1 is involved in the pathogenesis of house dust mite (HDM)-induced lung allergy. We found that knockdown of Bmal1 in macrophages suppressed the time-of-day variance of the eosinophil infiltration in the alveolar spaces in chronic asthmatic mice. This was accompanied by decreased bronchial mucus production, collagen deposition, and HDM-specific IgE production. However, the suppression effects of myeloid Bmal1 deletion did not alter the allergic responses in short-term exposure to HDM. The transcriptome profile of alveolar macrophages (AMs) showed that Bmal1-deficient AMs have enhanced phagocytosis and reduced production of allergy-mediating prostanoids thromboxane A2 and prostaglandin F2α synthesis. The attenuated thromboxane A2 and prostaglandin F2α may lead to less induction of the eosinophil chemokine Ccl11 expression in bronchial epithelial cells. In summary, our study demonstrates that Bmal1 ablation in macrophages attenuates eosinophilic inflammation in HDM-induced chronic lung allergy, which involves enhanced phagocytosis and reduced prostanoid secretion.

Functional role of glial-derived neurotrophic factor in a mixed allergen murine model of asthma

Our previous study showed that glial-derived neurotrophic factor (GDNF) expression is upregulated in asthmatic human lungs, and GDNF regulates calcium responses through its receptor GDNF family receptor α1 (GFRα1) and RET receptor in human airway smooth muscle (ASM) cells. In this study, we tested the hypothesis that airway GDNF contributes to airway hyperreactivity (AHR) and remodeling using a mixed allergen mouse model. Adult C57BL/6J mice were intranasally exposed to mixed allergens (ovalbumin, Aspergillus, Alternaria, house dust mite) over 4 wk with concurrent exposure to recombinant GDNF, or extracellular GDNF chelator GFRα1-Fc. Airway resistance and compliance to methacholine were assessed using FlexiVent. Lung expression of GDNF, GFRα1, RET, collagen, and fibronectin was examined by RT-PCR and histology staining. Allergen exposure increased GDNF expression in bronchial airways including ASM and epithelium. Laser capture microdissection of the ASM layer showed increased mRNA for GDNF, GFRα1, and RET in allergen-treated mice. Allergen exposure increased protein expression of GDNF and RET, but not GFRα1, in ASM. Intranasal administration of GDNF enhanced baseline responses to methacholine but did not consistently potentiate allergen effects. GDNF also induced airway thickening, and collagen deposition in bronchial airways. Chelation of GDNF by GFRα1-Fc attenuated allergen-induced AHR and particularly remodeling. These data suggest that locally produced GDNF, potentially derived from epithelium and/or ASM, contributes to AHR and remodeling relevant to asthma.NEW & NOTEWORTHY Local production of growth factors within the airway with autocrine/paracrine effects can promote features of asthma. Here, we show that glial-derived neurotrophic factor (GDNF) is a procontractile and proremodeling factor that contributes to allergen-induced airway hyperreactivity and tissue remodeling in a mouse model of asthma. Blocking GDNF signaling attenuates allergen-induced airway hyperreactivity and remodeling, suggesting a novel approach to alleviating structural and functional changes in the asthmatic airway.

Increased Risk of New-Onset Asthma After COVID-19: A Nationwide Population-Based Cohort Study

BACKGROUND

Previous studies have suggested that respiratory virus infections may be associated with new-onset asthma. However, whether coronavirus disease 2019 (COVID-19) is associated with an increased risk of new-onset asthma remains unclear.

OBJECTIVE

We aimed to evaluate whether recent COVID-19 increases the risk of new-onset asthma and whether COVID-19 vaccination could mitigate this risk.

METHODS

We constructed 3 different study designs using the Korean National Health Insurance claim-based database: study 1: COVID-19-diagnosed subjects (COVID-19 cohort) and their matched controls; study 2: COVID-19-vaccinated subjects (vaccination cohort) and their matched controls; and study 3: vaccination cohort and their matched controls, excluding subjects diagnosed with COVID-19.

RESULTS

In study 1, 1.6% of the COVID-19 cohort and 0.7% of the matched cohort developed new-onset asthma, with incidences of 31.28 and 14.55 per 1,000 person-years, respectively (P < .001). The COVID-19 cohort had a higher risk of new-onset asthma (adjusted hazard ratio [aHR] 2.14; 95% CI 1.88-2.45) than matched controls. In study 2, the vaccination cohort had a lower risk of new-onset asthma than the matched controls (aHR 0.82; 95% CI 0.76-0.89). However, among subjects without a COVID-19 diagnosis, COVID-19 vaccination was not associated with a reduced risk of new-onset asthma in study 3 (aHR 0.95; 95% CI 0.87-1.04). In subgroup analysis, the risk of new-onset asthma was significantly lower in fully vaccinated subjects and higher in older subjects and in those with diabetes mellitus than in their counterparts.

CONCLUSIONS

The COVID-19 was associated with a higher incidence of new-onset asthma, which might be preventable by COVID-19 vaccination.

Bronchial Asthma, Airway Remodeling and Lung Fibrosis as Successive Steps of One Process

Bronchial asthma is a heterogeneous disease characterized by persistent respiratory system inflammation, airway hyperreactivity, and airflow obstruction. Airway remodeling, defined as changes in airway wall structure such as extensive epithelial damage, airway smooth muscle hypertrophy, collagen deposition, and subepithelial fibrosis, is a key feature of asthma. Lung fibrosis is a common occurrence in the pathogenesis of fatal and long-term asthma, and it is associated with disease severity and resistance to therapy. It can thus be regarded as an irreversible consequence of asthma-induced airway inflammation and remodeling. Asthma heterogeneity presents several diagnostic challenges, particularly in distinguishing between chronic asthma and other pulmonary diseases characterized by disruption of normal lung architecture and functions, such as chronic obstructive pulmonary disease. The search for instruments that can predict the development of irreversible structural changes in the lungs, such as chronic components of airway remodeling and fibrosis, is particularly difficult. To overcome these challenges, significant efforts are being directed toward the discovery and investigation of molecular characteristics and biomarkers capable of distinguishing between different types of asthma as well as between asthma and other pulmonary disorders with similar structural characteristics. The main features of bronchial asthma etiology, pathogenesis, and morphological characteristics as well as asthma-associated airway remodeling and lung fibrosis as successive stages of one process will be discussed in this review. The most common murine models and biomarkers of asthma progression and post-asthmatic fibrosis will also be covered. The molecular mechanisms and key cellular players of the asthmatic process described and systematized in this review are intended to help in the search for new molecular markers and promising therapeutic targets for asthma prediction and therapy.

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.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

TMT-based quantitative proteomics revealed protective efficacy of Icariside II against airway inflammation and remodeling via inhibiting LAMP2, CTSD and CTSS expression in OVA-induced chronic asthma mice

BACKGROUND

Asthma is a chronic inflammatory disorder in airways with typical pathologic features of airflow limitation, airway inflammation and remodeling. Icariside II (IS), derived from herbal medicine Herba Epimedii, exerts an anti-inflammatory property. However, underlying mechanisms with specifically targeted molecular expression by IS in asthma have not been fully understood, and whether IS could inhibit remodeling and EMT still remains unclear.

PURPOSE

The study aimed to clarify therapeutic efficacy of IS for attenuating airway inflammation and remodeling in asthma, and illustrate IS-regulated specific pathway and target proteins through TMT-based quantitative proteomics.

STUDY DESIGN AND METHODS

Murine model of chronic asthma was constructed with ovalbumin (OVA) sensitization and then challenge for 8 weeks. Pulmonary function, leukocyte count in bronchoalveolar lavage fluid (BALF), lung histopathology, inflammatory and fibrotic cytokines, and markers of epithelial-mesenchymal transition (EMT) were evaluated. TMT-based quantitative proteomics were performed on lung tissues to explore IS-regulated proteins.

RESULTS

IS contributed to alleviative airway hyperresponsiveness (AHR) evidenced by declined R_L and increased Cdyn. After IS treatment, we observed a remarked down-regulation of leukocyte count, inflammatory cytokines in BALF, and peribronchial inflammation infiltration. Goblet cell hyperplasia, mucus secretion and peribronchial collagen deposition were attenuated, with the level of TGF-β and MMP-9 in BALF declined. Furthermore, IS induced a rise of Occludin and E-cadherin and a decline of N-cadherin and α-SMA in lung tissues. These results proved the protective property of IS against airway inflammation, remodeling and EMT. To further investigate underlying mechanisms of IS in asthma treatment, TMT-based quantitative proteomics were performed and 102 overlapped DEPs regulated by IS were identified. KEGG enrichment exhibited these DEPs were enriched in lysosome, phagosome and autophagy, in which LAMP2, CTSD and CTSS were common DEPs. WB, q-PCR and IHC results proofed expressional alteration of these proteins. Besides, IS could decrease Beclin-1 and LC3B expression with increasing p62 expression thus inhibiting autophagy.

CONCLUSIONS

The study demonstrated IS could ameliorate AHR, airway inflammation, remodeling and EMT in OVA-induced chronic asthma mice. Our research was the first to reveal that inhibition of LAMP2, CTSD and CTSS expression in autophagy contributed to the therapeutic efficacy of IS to asthma.

Mast Cells in Upper and Lower Airway Diseases: Sentinels in the Front Line

Mast cells (MCs) are fascinating cells of the innate immune system involved not only in allergic reaction but also in tissue homeostasis, response to infection, wound healing, protection against kidney injury, the effects of pollution and, in some circumstances, cancer. Indeed, exploring their role in respiratory allergic diseases would give us, perhaps, novel therapy targets. Based on this, there is currently a great demand for therapeutic regimens to enfeeble the damaging impact of MCs in these pathological conditions. Several strategies can accomplish this at different levels in response to MC activation, including targeting individual mediators released by MCs, blockade of receptors for MC-released compounds, inhibition of MC activation, limiting mast cell growth, or inducing mast cell apoptosis. The current work focuses on and summarizes the mast cells' role in pathogenesis and as a personalized treatment target in allergic rhinitis and asthma; even these supposed treatments are still at the preclinical stage.

Relief of ovalbumin-induced airway remodeling by the glycyl-l-histidyl-l-lysine-Cu2+ tripeptide complex via activation of SIRT1 in airway epithelial cells

Fixed airflow limitation (FAO), prevalent in patients with severe or difficult-to-treat asthma, is mainly caused by airway remodeling. Airway remodeling is initiated by inflammation and involves subsequent pathological changes. Glycyl-l-histidyl-l-lysine (GHK) is a matrikine with anti-inflammatory and antioxidant effects, naturally existing in human tissue. At present, the GHK level in human plasma and whether it is related to airway remodeling of asthma remain unclear. This study was conducted to determine how GHK is involved in airway remodeling in asthma. Our result showed that the plasma GHK levels of patients with asthma were significantly lower than those of age-matched healthy controls. In asthma patients, plasma GHK levels display a moderate correlation with FEF_25-75%, and patients with FAO had significantly lower GHK levels. Ovalbumin-induced mice of asthma model treated with PBS or GHK-Cu (a form of GHK with higher bioavailability) were used to evaluate the effect of exogenous GHK supplement on airway remodeling. GHK-Cu administration alleviated airway remodeling, as reflected by decreased peribronchial collagen deposition and airway mucus secretion, and suppressed epithelial-mesenchymal transition. The therapeutical effect related to decreased TGF-β1 level. Successively, network pharmacology and the validation data of experiments in vivo and vitro demonstrated that GHK-Cu decreased TGF-β1 level by increasing SIRT1 expression and activating SIRT1 deacetylation in airway epithelial cells, thereby alleviating airway remodeling. Collectively, decreased plasma GHK levels were related to FAO in asthma patients. Through the direct binding and activation of SIRT1, exogenous GHK-Cu administration alleviated airway remodeling in asthmatic mice.

The Identification and Clinical Value Evaluation of CYCS Related to Asthma through Bioinformatics Analysis and Functional Experiments

Background

Asthma is one of the most common respiratory diseases and one of the largest burdens of health care resources across the world. This study is aimed at using bioinformatics methods to find effective clinical indicators for asthma and conducting experimental validation.

Methods

We downloaded GSE64913 data and performed differentially expressed gene (DEG) screening. Weighted gene coexpression network analysis (WGCNA) on DEGs was applied to identify key module most associated with asthma for protein-protein interaction (PPI) analysis. According to the degree value, ten genes were obtained and subjected to expression analysis and receiver operating characteristic (ROC) analysis. Next, key genes were screened for expression analysis and immunological analysis. Finally, cell counting kit-8 (CCK-8) and qRT-PCR were also conducted to observe the influence of hub gene on cell proliferation and inflammatory cytokines.

Results

From the GSE64913 dataset, 711 upregulated and 684 downregulated DEGs were found. In WGCNA, the top 10 genes in the key module were examined by expression analysis in asthma, and CYCS was determined as an asthma-related oncogene with a good predictive ability for the prognosis of asthmatic patients. CYCS is significantly associated with immune cells, such as HHLA2, IDO1, TGFBR1, and CCL18 and promoted the proliferation of asthmatic cells in vitro.

Conclusion

CYCS plays an oncogenic role in the pathophysiology of asthma, indicating that this gene may become a novel diagnostic biomarker and promising target of asthma treatment.

LXA4 inhibits TGF-β1-induced airway smooth muscle cells proliferation and migration by suppressing the Smad/YAP pathway

The aims of the present study were to examine the signaling mechanisms for transforming growth factor-β1 (TGF-β1)-induced rat airway smooth muscle cells (ASMCs) proliferation and migration and to determine the effect of lipoxin A4 (LXA4) on TGF-β1-induced rat ASMCs proliferation and migration and its underlying mechanisms. TGF-β1 upregulated transcriptional coactivator Yes-associated protein (YAP) expression by activating Smad2/3 and then upregulated cyclin D1, leading to rat ASMCs proliferation and migration. This effect was reversed after treatment with the TGF-β1 receptor inhibitor SB431542. YAP is a critical mediator of TGF-β1-induced ASMCs proliferation and migration. Knockdown of YAP disrupted the pro-airway remodeling function of TGF-β1. Preincubation of rat ASMCs with LXA4 blocked TGF-β1-induced activation of Smad2/3 and changed its downstream targets, YAP and cyclin D1, resulting in the inhibition of rat ASMCs proliferation and migration. Our study suggests that LXA4 suppresses Smad/YAP signaling to inhibit rat ASMCs proliferation and migration and therefore has potential value in the prevention and treatment of asthma by negatively modulating airway remodeling.

IRAK-M Regulates Proliferative and Invasive Phenotypes of Lung Fibroblasts

Lung fibroblasts play an important role in subepithelial fibrosis, one feature for airway remodeling. IL-1 receptor-associated kinase (IRAK)-M was shown to involve fibrosis formation in airways and lung through regulation of inflammatory responses. IRAK-M is expressed by lung fibroblasts, whether IRAK-M has direct impact on lung fibroblasts remains unclear. In this investigation, we evaluated in vitro effect of IRAK-M on phenotypes of lung fibroblasts by silencing or overexpressing IRAK-M. Murine lung fibroblasts (MLg) were stimulated with house dust mite (HDM), IL-33, and transforming growth factor (TGF) β1. Techniques of small interfering RNA or expression plasmid were employed to silence or overexpress IRAK-M in MLg fibroblast cells. Proliferation, migration, invasiveness, and fibrosis-related events were evaluated. Significant upregulation of IRAK-M expression in MLg cells was caused by these stimuli. Silencing IRAK-M significantly increased proliferation, migration, and invasiveness of lung fibroblasts regardless of stimulating conditions. By contrast, IRAK-M overexpression significantly inhibited proliferation and motility of MLg lung fibroblasts. IRAK-M overexpression also significantly decreased the expression of fibronectin, collagen I, and α-SMA in MLg cells. Under stimulation with TGFβ1 or IL-33, IRAK-M silencing reduced MMP9 production, while IRAK-M overexpression increased MMP9 production. Modulation of IRAK-M expression affected cytokines production, either decreased or increased expression of TNFα and CXCL10 by the cells regardless of stimulation. Our in vitro data reveal that IRAK-M directly impacts on lung fibroblasts through modulation of cellular motility, release of inflammatory, and fibrotic cytokines of lung fibroblasts. These might suggest a new target by regulation of IRAK-M in slowing airway remodeling.

In vitro human cell-based models to study airway remodeling in asthma

Airway remodeling, as a predominant characteristic of asthma, refers to the structural changes that occurred both in the large and small airways. These pathological changes not only contribute to airway hyperresponsiveness and airway obstruction, but also predict poor outcomes of patients. In vitro models are the alternatives to animal models that facilitate airway remodeling research. Current approaches to mimic airway remodeling in vitro include mono cultures of cell lines and primary cells that are derived from the respiratory tract, and co-culture systems that consist of different cell subpopulations. Moreover, recent advances in microfluid chips and organoids show promise in simulating the complex architecture and functionality of native organs. According, they enable highly physiological-relevant investigations of human diseases in vitro. Here we aim to detail the current human cell-based models regarding their key pros and cons, and to discuss how they may be used to facilitate our understanding of airway remodeling in asthma.

Therapeutic potential of recombinant human basic fibroblast growth factor on postoperative patients with chronic rhinosinusitis with nasal polyps

OBJECTIVES

To explore the effect of intranasal administration of recombinant human basic fibroblast growth factor (rh-bFGF) on postoperative chronic rhinosinusitis with nasal polyps (CRSwNP) patients.

DESIGN

A prospective, randomised, controlled, single-blinded trial.

SETTING AND PARTICIPANTS

Seventy-five hospitalised patients who met the criteria of primary bilateral CRSwNP were enrolled from March 2020 to January 2021.

MAIN OUTCOME MEASURES

Visual analogue scale, 22-item Sino-Nasal Outcome Test, Lund-Kennedy (L-K) system and scanning electron microscopy and quantitative real-time polymerase chain reaction.

RESULTS

Seventy-five patients with CRSwNP were randomly assigned to three groups, and 72 patients completed the 1-month medication regimen and 1-year follow-up. Rh-bFGF nasal-spray and drop application reduced general nasal VAS scores within 2 weeks after endoscopic sinus surgery (ESS) compared to the control group. In contrast, only rh-bFGF nasal-drops reduced SNOT-22 scores at 2 weeks and 1 year compared with the control group. A significant reduction in the endoscopic L-K score was observed in the rh-bFGF nasal-spray and drop group compared with the control group. This is primarily because rh-bFGF promotes cilia growth in the nasal mucosal epithelium after the operation, as illustrated by scanning electron microscopy and expression of CP110, Tap73 and Foxj1 mRNA. For eosinophilic CRSwNP, the general VAS score of rh-bFGF nasal-drops was more obviously reduced compared to the control group after ESS. A similar trend was observed for L-K score.

CONCLUSIONS

Rh-bFGF nasal-drops and sprays can quickly and effectively relieve postoperative symptoms and improve long-term prognosis of patients with CRSwNP. Moreover, rh-bFGF nasal-drops is also an effective method for postoperative patients with eosinophilic CRSwNP.

Apolipoprotein E negatively regulates allergic airway inflammation and remodeling in mice with OVA-induced chronic asthma

Apolipoprotein E (ApoE) is a corticosteroid-unresponsive gene that negatively regulates ovalbumin (OVA) -induced allergic airway inflammation in mice with acute asthma. However, whether ApoE negatively regulates airway remodeling in mice with OVA-induced chronic asthma remains unknown. This study aimed to investigate the effects of ApoE on OVA-induced chronic asthma in a murine model. ApoE knockout (ApoE^-/-) and wild-type (WT) mice were sensitized and challenged with OVA for 10 weeks to establish the chronic asthma model. Compared with WT mice, the results demonstrated that ApoE deficiency exacerbated OVA-induced airway inflammation, including elevated numbers of inflammatory cells in the blood and bronchoalveolar lavage fluid (BALF), as well as increased T helper type 2 (Th2) cells in lung tissue, Th2 cytokines in BALF, and total IgE levels in plasma. Importantly, ApoE deficiency aggravated OVA-induced airway remodeling, as evidenced by higher plasma transforming growth factor (TGF)-β1 levels, airway goblet cell hyperplasia, and collagen deposition compared with WT mice. These results revealed that ApoE deficiency aggravates airway remodeling and inflammation in mice with OVA-induced chronic allergic asthma.

The molecular mechanisms of remodeling in asthma, COPD and IPF with a special emphasis on the complex role of Wnt5A

INTRODUCTION

Chronic inflammatory lung diseases are a common cause of suffering and death. Chronic obstructive pulmonary disease (COPD) is the reason for 6% of all deaths worldwide. A total of 262 million people are affected by asthma and 461,000 people died in 2019. Idiopathic pulmonary fibrosis (IPF) is diagnosed in 3 million people worldwide, with an onset over the age of 50 with a mean survival of only 24-30 months. These three diseases have in common that remodeling of the lung tissue takes place, which is responsible for an irreversible decline of lung function. Pathological lung remodeling is mediated by a complex interaction of different, often misguided, repair processes regulated by a variety of mediators. One group of these, as has recently become known, are the Wnt ligands. In addition to their well-characterized role in embryogenesis, this group of glycoproteins is also involved in immunological and structural repair processes. Depending on the combination of the Wnt ligand with its receptors and co-receptors, canonical and noncanonical signaling cascades can be induced. Wnt5A is a mediator that is described mainly in noncanonical Wnt signaling and has been shown to play an important role in different inflammatory diseases and malignancies.

OBJECTIVES

In this review, we summarize the literature available regarding the role of Wnt5A as an immune modulator and its role in the development of asthma, COPD and IPF. We will focus specifically on what is known about Wnt5A concerning its role in the remodeling processes involved in the chronification of the diseases.

CONCLUSION

Wnt5A has been shown to be involved in all three inflammatory lung diseases. Since the ligand affects both structural and immunological processes, it is an interesting target for the treatment of lung diseases whose pathology involves a restructuring of the lung tissue triggered in part by an inflammatory immune response.

Blood Inflammatory-like and Lung Resident-like Eosinophils Affect Migration of Airway Smooth Muscle Cells and Their ECM-Related Proliferation in Asthma

Airway remodeling is a hallmark feature of asthma, and one of its key structural changes is increased airway smooth muscle (ASM) mass and disturbed extracellular matrix (ECM) homeostasis. Eosinophil functions in asthma are broadly defined; however, we lack knowledge about eosinophil subtypes' interaction with lung structural cells and their effect on the airway's local microenvironment. Therefore, we investigated the effect of blood inflammatory-like eosinophils (iEOS-like) and lung resident-like eosinophils (rEOS-like) on ASM cells via impact on their migration and ECM-related proliferation in asthma. A total of 17 non-severe steroid-free allergic asthma (AA), 15 severe eosinophilic asthma (SEA) patients, and 12 healthy control subjects (HS) were involved in this study. Peripheral blood eosinophils were enriched using Ficoll gradient centrifugation and magnetic separation, subtyped by using magnetic separation against CD62L. ASM cell proliferation was assessed by AlamarBlue assay, migration by wound healing assay, and gene expression by qRT-PCR analysis. We found that blood iEOS-like and rEOS-like cells from AA and SEA patients' upregulated genes expression of contractile apparatus proteins, COL1A1, FN, TGF-β1 in ASM cells (p < 0.05), and SEA eosinophil subtypes demonstrated the highest effect on sm-MHC, SM22, and COL1A1 gene expression. Moreover, AA and SEA patients' blood eosinophil subtypes promoted migration of ASM cells and their ECM-related proliferation, compared with HS (p < 0.05) with the higher effect of rEOS-like cells. In conclusion, blood eosinophil subtypes may contribute to airway remodeling by upregulating contractile apparatus and ECM component production in ASM cells, further promoting their migration and ECM-related proliferation, with a stronger effect of rEOS-like cells and in SEA.

Collagen Triple Helix Repeat Containing 1 Deficiency Protects Against Airway Remodeling and Inflammation in Asthma Models In Vivo and In Vitro

Asthma is a chronic inflammatory disease characterized by airway remodeling and lung inflammation. Collagen triple helix repeat containing 1 (CTHRC1), a glycoprotein, is involved in multiple pathological processes, including inflammation and fibrosis. However, the function of CTHRC1 in asthma remains unclear. In the present study, the mouse asthma model was successfully generated by sensitizing and challenging mice with ovalbumin (OVA). CTHRC1 expression at both RNA and protein levels was significantly upregulated in lung tissues of asthmatic mice. Asthmatic mice exhibited significant airway remodeling as evidenced by increased bronchial wall and smooth muscle cell layer thickness, goblet cell hyperplasia and collagen deposition, and epithelial-mesenchymal transition (EMT), but those characteristics were reversed by CTHRC1 silencing. The cell model with transforming growth factor-β1 (TGF-β1) induction in bronchial epithelial cells (BEAS-2B) was conducted to verify the effects of CTHRC1 on EMT, a classic mechanism that mediates airway remodeling. The results showed that TGF-β1 stimulation increased CTHRC1 expression, and CTHRC1 knockdown inhibited TGF-β1-induced EMT. OVA-treated mice also showed increased inflammatory cell infiltration and the production of OVA-specific immunoglobulin E (IgE), interleukin (IL)-4, IL-5, and IL-13, which were decreased by CTHRC1 downregulation. The effects of CTHRC1 on OVA-induced airway inflammation were further determined by treating BEAS-2B cells with IL-13, in which CTHRC1 knockdown reduced the IL-13-induced secretion of pro-inflammatory factors, including IL-4 and IL-5. In conclusion, these results indicate that CTHRC1 silencing attenuates asthmatic airway remodeling and inflammation in vivo and in vitro, suggesting that CTHRC1 may be a potential target for asthma treatment.

Vanadium exposure exacerbates allergic airway inflammation and remodeling through triggering reactive oxidative stress

Background

Metal components of environmental PM2.5 are associated with the exacerbation of allergic diseases like asthma. In our recent hospital-based population study, exposure to vanadium is shown to pose a significant risk for current asthma, but the causal relationship and its underlying molecular mechanisms remain unclear.

Objective

We sought to determine whether vanadium co-exposure can aggravate house dust mite (HDM)-induced allergic airway inflammation and remodeling, as well as investigate its related mechanisms.

Methods

Asthma mouse model was generated by using either vanadium pentoxide (V₂O₅) or HDM alone or in combination, in which the airway inflammation and remodeling was investigated. The effect of V₂O₅ co-exposure on HDM-induced epithelial-derived cytokine release and oxidative stress (ROS) generation was also examined by in vitro analyses. The role of ROS in V₂O₅ co-exposure-induced cytokine release and airway inflammation and remodeling was examined by using inhibitors or antioxidant.

Results

Compared to HDM alone, V₂O₅ co-exposure exacerbated HDM-induced airway inflammation with increased infiltration of inflammatory cells and elevated levels of Th1/Th2/Th17 and epithelial-derived (IL-25, TSLP) cytokines in the bronchoalveolar lavage fluids (BALFs). Intriguingly, V₂O₅ co-exposure also potentiated HDM-induced airway remodeling. Increased cytokine release was further supported by in vitro analysis in human bronchial epithelial cells (HBECs). Mechanistically, ROS, particularly mitochondrial-derived ROS, was significantly enhanced in HBECs after V₂O₅ co-exposure as compared to HDM challenge alone. Inhibition of ROS with its inhibitor N-acetyl-L-cysteine (NAC) and mitochondrial-targeted antioxidant MitoTEMPO blocked the increased epithelial release caused by V₂O₅ co-exposure. Furthermore, vitamin D₃ as an antioxidant was found to inhibit V₂O₅ co-exposure-induced increased airway epithelial cytokine release and airway remodeling.

Conclusions

Our findings suggest that vanadium co-exposure exacerbates epithelial ROS generation that contribute to increased allergic airway inflammation and remodeling.

Vanadium exposure exacerbates allergic airway inflammation and remodeling through triggering reactive oxidative stress

Background

Metal components of environmental PM2.5 are associated with the exacerbation of allergic diseases like asthma. In our recent hospital-based population study, exposure to vanadium is shown to pose a significant risk for current asthma, but the causal relationship and its underlying molecular mechanisms remain unclear.

Objective

We sought to determine whether vanadium co-exposure can aggravate house dust mite (HDM)-induced allergic airway inflammation and remodeling, as well as investigate its related mechanisms.

Methods

Asthma mouse model was generated by using either vanadium pentoxide (V2O5) or HDM alone or in combination, in which the airway inflammation and remodeling was investigated. The effect of V2O5 co-exposure on HDM-induced epithelial-derived cytokine release and oxidative stress (ROS) generation was also examined by in vitro analyses. The role of ROS in V2O5 co-exposure-induced cytokine release and airway inflammation and remodeling was examined by using inhibitors or antioxidant.

Results

Compared to HDM alone, V2O5 co-exposure exacerbated HDM-induced airway inflammation with increased infiltration of inflammatory cells and elevated levels of Th1/Th2/Th17 and epithelial-derived (IL-25, TSLP) cytokines in the bronchoalveolar lavage fluids (BALFs). Intriguingly, V2O5 co-exposure also potentiated HDM-induced airway remodeling. Increased cytokine release was further supported by in vitro analysis in human bronchial epithelial cells (HBECs). Mechanistically, ROS, particularly mitochondrial-derived ROS, was significantly enhanced in HBECs after V2O5 co-exposure as compared to HDM challenge alone. Inhibition of ROS with its inhibitor N-acetyl-L-cysteine (NAC) and mitochondrial-targeted antioxidant MitoTEMPO blocked the increased epithelial release caused by V2O5 co-exposure. Furthermore, vitamin D3 as an antioxidant was found to inhibit V2O5 co-exposure-induced increased airway epithelial cytokine release and airway remodeling.

Conclusions

Our findings suggest that vanadium co-exposure exacerbates epithelial ROS generation that contribute to increased allergic airway inflammation and remodeling.

The anti-asthmatic potential of Rho-kinase inhibitor hydroxyfasudil in the model of experimentally induced allergic airway inflammation

OBJECTIVE

This experimental study evaluated the anti-asthmatic potential of the Rho-kinase inhibitor hydroxyfasudil in the settings of allergen-induced allergen-induced experimental asthma.

METHODS

Chronic allergic airway inflammation was caused by 28 days-sensitisation of guinea pigs with ovalbumin (OVA). Hydroxyfasudil was administered intraperitoneally in two doses for the last two weeks (1 mg/kg b.w.; 10 mg/kg b.w.). The degree of allergic inflammation was determined based on concentrations of inflammatory Th2 cytokines (IL-4, IL-13), Th1 cytokines (TNF-α and IFN-γ) in the lung homogenate and leukocyte count in the bronchoalveolar lavage fluid (BALF). The markers of remodelling and fibrosis, the growth factors (TGF-β1, EGF), EGF receptor, collagen type III and V were estimated in lung homogenate. The changes in specific airway resistance (sRaw) were used as an in vivo bronchial hyperreactivity parameter.

RESULTS

Hydroxyfasudil administration at both doses significantly reduced sRaw after a week of therapy. We observed a decline of IL-13, TNF-α and IFN-γ in lung homogenate and a lower presence of lymphocytes in BALF after 14 days of hydroxyfasudil administration at both tested doses. Hydroxyfasudil 14 days-treatment at both doses effectively reduced the concentrations of TGF-β1, EGF receptors, collagen type III and V in BALF and modulated EGF levels.

CONCLUSIONS

These findings indicate that RhoA/Rho-kinase is involved in the pathophysiology of allergic airway inflammation and suggest that Rho-kinase inhibitor hydroxyfasudil has therapeutic potential for asthma management.

Symptom-driven inhaled corticosteroid/long-acting beta-agonist therapy for adult patients with asthma who are non-adherent to daily maintenance inhalers: a study protocol for a pragmatic randomized controlled trial

BACKGROUND

While inhaled corticosteroids (ICS) are considered the essential foundation of most asthma therapy, ICS inhaler nonadherence is a notoriously common problem and a significant cause of asthma-related morbidity. Partially acknowledging the problem of nonadherence, international organizations recently made paradigm-shifting recommendations that all patients with mild-to-moderate persistent asthma be considered for symptom-driven ICS-containing inhalers rather than relying on adherence to traditional maintenance ICS inhalers and symptom-driven short-acting beta-agonists (SABA). With this new approach, asthma patients are at least exposed to the important anti-inflammatory effects of ICS-containing inhalers when their symptom reliever inhaler is deployed due to acute symptoms.

METHODS

This study will (Part 1) complete a pragmatic randomized controlled trial to evaluate if an inhaler strategy that utilizes symptom-driven ICS inhalers is particularly beneficial in maintenance ICS inhaler non-adherent asthma patients, and (Part 2) use a dissemination and implementation (D&I) science conceptual framework to better understand patients' and providers' views of inhaler nonadherence. This study, which will have an option of taking place entirely remotely, will use a Food and Drug Administration (FDA)-approved electronic sensor (Hailie® sensor) to monitor inhaler adherence and includes semi-structured interviews guided by the Consolidated Framework for Implementation Research (CFIR).

DISCUSSION

This study is assessing the problem of nonadherence using a D&I implementation science research lens while testing a new inhaler approach to potentially ameliorate the detrimental consequences of maintenance inhaler nonadherence. We hypothesize that the use of a symptom-driven ICS/LABA management strategy, as compared to traditional maintenance ICS treatment and symptom-driven SABA, will lead to improved adherence to an asthma treatment strategy, decreased asthma-related morbidity, less cumulative ICS exposure, and greater patient satisfaction with an inhaler approach.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05111262. Registered on November 8, 2021.

Rhinovirus Infection and Virus-Induced Asthma

While the aetiology of asthma is unclear, the onset and/or exacerbation of asthma may be associated with respiratory infections. Virus-induced asthma is also known as virus-associated/triggered asthma, and the reported main causative agent is rhinovirus (RV). Understanding the relationship between viral infections and asthma may overcome the gaps in deferential immunity between viral infections and allergies. Moreover, understanding the complicated cytokine networks involved in RV infection may be necessary. Therefore, the complexity of RV-induced asthma is not only owing to the response of airway and immune cells against viral infection, but also to allergic immune responses caused by the wide variety of cytokines produced by these cells. To better understand RV-induced asthma, it is necessary to elucidate the nature RV infections and the corresponding host defence mechanisms. In this review, we attempt to organise the complexity of RV-induced asthma to make it easily understandable for readers.

In Silico Evaluation of Nonsynonymous SNPs in Human ADAM33: The Most Common Form of Genetic Association to Asthma Susceptibility

ADAM33 is a zinc-dependent metalloprotease of the ADAM family, which plays a vital biological role as an activator of Th2 cytokines and growth factors. Moreover, this protein is crucial for the normal development of the lung in the fetus two months after gestation leading to determining lung functions all over life. In this regard, mutations in ADAM33 have been linked with asthma risk factors. Consequently, identifying ADAM33 pathogenic nonsynonymous single-nucleotide polymorphisms (nsSNPs) can be very important in asthma treatment. In the present study, 1055 nsSNPs of human ADAM33 were analyzed using biocomputational software, 31 of which were found to be detrimental mutations. Precise structural and stability analysis revealed D219V, C669G, and C606S as the most destabilizing SNPs. Furthermore, MD simulations disclosed higher overall fluctuation and alteration in intramolecular interactions compared with the wild-type structure. Overall, the results suggest D219V, C669G, and C606S detrimental mutations as a starting point for further case-control studies on the ADAM33 protein as well as an essential source for future targeted mechanisms.

A novel iridoid glycoside leonuride (ajugol) attenuates airway inflammation and remodeling through inhibiting type-2 high cytokine/chemokine activity in OVA-induced asthmatic mice

BACKGROUND

Asthma is a chronic airway disorder with a hallmark feature of airflow obstruction that associated with the remodeling and inflammation in the airway wall. Effective therapy for controlling both remodeling and inflammation is still urgently needed. Leonuride is the main pharmacological component identified from Bu-Shen-Yi-Qi-Tang (BSYQT) which has been traditionally used in treatment of lung diseases. However, no pharmacological effects of leonuride in asthma were reported.

PURPOSE

Here we aimed to investigated whether leonuride provided a therapeutic efficacy in reversing asthma airway remodeling and inflammation and uncover the underlying mechanisms.

STUDY DESIGN AND METHODS

Mouse models of chronic asthma were developed with ovalbumin (OVA) exposure for 8 weeks. Respiratory mechanics, lung histopathology and asthma-related cytokines were examined. Lung tissues were analyzed using RNA sequencing to reveal the transcriptional profiling changes.

RESULTS

After oral administration with leonuride (15 mg/kg or 30 mg/kg), mice exhibited a lower airway hyperresponsiveness in comparison to asthmatic mice. Leonuride suppressed airway inflammation evidenced by the significant reductions in accumulation of inflammatory cells around bronchi and vessels, leukocyte population counts and the abundance of type 2 inflammatory mediators (OVA specific IgE, IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF). On the other hand, leonuride slowed down the process of active remodeling as demonstrated by weaker goblet cell metaplasia and subepithelial fibrosis in lung histopathology and lower transforming growth factor (TGF)-β1 levels in serum and BALF in comparison to mice treated with OVA only. Furthermore, we uncovered transcriptional profiling alternations in lung tissue of mice after OVA exposure and leonuride treatment. Gene sets belonging to type-2 cytokine/chemokine activity stood out in leonuride target transcripts. Those upregulated (Bmp10, Ccl12, Ccl22, Ccl8, Ccl9, Cxcl15, Il13, Il33, Tnfrsf9, Il31ra, Il5ra, Il13ra2 and Ccl24) or downregulated (Acvr1c and Il18) genes in asthmatic mice, were all reversely regulated by leonuride treatment.

CONCLUSIONS

Our results revealed the therapeutic efficacy of leonuride in experimental chronic asthma for the first time, and implied that its anti-inflammatory and antifibrotic properties might be mediated by regulation of type-2 high cytokine/chemokines responses.

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.

Modulation of Arginase-2 mRNA Levels by ω-3 PUFAs and Aspirin in Asthmatic Human Lung Fibroblasts

Airway remodeling (AR) increases disease severity, and morbidity of asthmatic patients by contributing to irreversible airflow obstruction and progressive declines in lung function. Arginase isoenzymes and the downstream enzymes ornithine decarboxylase (ODC) and ornithine aminotransferase (OAT) have been implicated in the hyperplastic and fibrotic changes of AR, respectively. Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and resolvin metabolites have anti-AR effects, but whether they are mediated through the arginase pathway is unclear. Our study intended to determine the effects of the ω-3 PUFAs eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), resolvin D1 (RvD1), TH1 cytokines, acetylsalicylic acid (ASA), cAMP, and dexamethasone (DEX) on the expression of arginase isoenzymes arginase 1 (ARG1) and arginase 2 (ARG2), ODC, and OAT in human lung fibroblasts (HLF) from normal (NHLF) and diseased (DHLF) asthmatic donors using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). Our data showed that EPA and EPA+DHA downregulated ARG2 mRNA 2-fold in both types of HLF. DHA, RvD1, and DEX did not alter mRNA levels for any of the genes studied. EPA lowered the ARG2 protein levels in DHLF, but did not affect those levels in NHLF. ASA upregulated ARG2 mRNA 5-fold and 7-fold in NHLF and DHLF, respectively, TH1 cytokines downregulated ARG2, ODC, and OAT mRNA in DHLF 10-fold, 2-fold, and 2.5-fold, respectively, and cAMP downregulated ARG2 mRNA 2-fold in DHLF. These results are the first to show a direct effect of ω-3 PUFAs on ARG2 mRNA levels and provide further evidence for a role of ω-3 PUFAs in AR.

Exposure to Sodium Hypochlorite or Cigarette Smoke Induces Lung Injury and Mechanical Impairment in Wistar Rats

Pulmonary irritants, such as cigarette smoke (CS) and sodium hypochlorite (NaClO), are associated to pulmonary diseases in cleaning workers. We examined whether their association affects lung mechanics and inflammation in Wistar rats. Exposure to these irritants alone induced alterations in the lung mechanics, inflammation, and remodeling. The CS increased airway cell infiltration, acid mucus production, MMP-12 expression, and alveolar enlargement. NaClO increased the number of eosinophils and macrophages in the bronchoalveolar lavage fluid, with cells expressing IL-13, MMP-12, MMP-9, TIMP-1, and iNOS in addition to increased IL-1β and TNF-α levels. Co-exposure to both irritants increased epithelial and smooth muscle cell area, acid mucus production, and IL-13 expression in the airways, while it reduced the lung inflammation. In conclusion, the co-exposure of CS with NaClO reduced the pulmonary inflammation, but increased the acidity of mucus, which may protect lungs from more injury. A cross-resistance in people exposed to multiple lung irritants should also be considered.

Chemokine CXCL12 drives pericyte accumulation and airway remodeling in allergic airway disease

Background

Airway remodeling is a significant contributor to impaired lung function in chronic allergic airway disease. Currently, no therapy exists that is capable of targeting these structural changes and the consequent loss of function. In the context of chronic allergic inflammation, pericytes have been shown to uncouple from the pulmonary microvasculature, migrate to areas of inflammation, and significantly contribute to airway wall remodeling and lung dysfunction. This study aimed to elucidate the mechanism by which pulmonary pericytes accumulate in the airway wall in a model of chronic allergic airway inflammation.

Methods

Mice were subjected to a protocol of chronic airway inflammation driven by the common environmental aeroallergen house dust mite. Phenotypic changes to lung pericytes were assessed by flow cytometry and immunostaining, and the functional capacity of these cells was evaluated using in vitro migration assays. The molecular mechanisms driving these processes were targeted pharmacologically in vivo and in vitro.

Results

Pericytes demonstrated increased CXCR4 expression in response to chronic allergic inflammation and migrated more readily to its cognate chemokine, CXCL12. This increase in migratory capacity was accompanied by pericyte accumulation in the airway wall, increased smooth muscle thickness, and symptoms of respiratory distress. Pericyte uncoupling from pulmonary vessels and subsequent migration to the airway wall were abrogated following topical treatment with the CXCL12 neutraligand LIT-927.

Conclusion

These results provide new insight into the role of the CXCL12/CXCR4 signaling axis in promoting pulmonary pericyte accumulation and airway remodeling and validate a novel target to address tissue remodeling associated with chronic inflammation.

Chloroquine Attenuates Asthma Development by Restoring Airway Smooth Muscle Cell Phenotype Via the ROS-AKT Pathway

Switching of airway smooth muscle (ASM) cell phenotype from differentiated-contractile to dedifferentiated-proliferative/synthetic state often occurs in asthmatic subjects with airway dysfunction. Evidence has been provided that chloroquine (an agonist of bitter taste receptors) presented benefits to ASM cell function implicated in asthma. However, the underlying mechanism is unclear. House dust mite (HDM)-sensitized mice were administered with chloroquine or dexamethasone before challenge. BALF and lung tissue were obtained for cell counting, histological analysis or ELISA. Primary cultured ASM cells were stimulated with transforming growth factor (TGF)-β1 or H₂O₂. Cells and supernatant were collected for the detection of ASM phenotype, ROS level, and proinflammatory cytokine production. In HDM-sensitized mice, chloroquine attenuated airway hyperresponsiveness (AHR), inflammation and remodeling with an inhibition of immunoglobulin E, IL-4/-13, and TGF-β1 in BALF. ASM cell proliferation (PCNA), hypertrophy (α-SMA), and parasecretion (MMP-9 and MMP-13) were strongly suppressed by chloroquine, hinting the rebalance of the heterogeneous ASM populations in asthmatic airway. Our data in vitro indicated that chloroquine markedly restrained maladaptive alteration in ASM phenotype in concert with a remission of ROS. Using H₂O₂ and PI3K inhibitor (LY294002), we found that the inhibition of oxidative stress level and ROS-AKT signal by chloroquine may serve as a potential mechanism that dedicates to the restoration of the phenotypic imbalance in ASM cells. Overall, the present findings suggested that chloroquine improves asthmatic airway function by controlling ASM cell phenotype shift, sketching a novel profile of chloroquine as a new therapeutic candidate for airway remodeling.

Airway fibrin formation cascade in allergic asthma exacerbation: implications for inflammation and remodeling

BACKGROUND

Airway remodeling in patients with asthma, which leads to a decline in pulmonary function, is likely the result of repeated exacerbations often provoked by aeroallergen exposures. Aeroallegen exposure triggers a stereotypic response orchestrated by growth factor cytokines and other protein mediators. This results in a late-phase allergic reaction characterized by vascular permeability, recruitment of activated leukocytes, and activation of structural cells of the airway. The spectrum of protein mediators and their functions are incompletely understood.

METHODS

Bronchoalveolar lavage fluid (BALF) samples were obtained from 12 volunteers who exhibited robust eosinophilic recruitment following segmental bronchial provocation with allergen (SBP-Ag). We systematically identified and quantified proteins in BALF using high-performance liquid chromatography-high-resolution mass spectrometry (LC-MS/MS) followed by pathway analysis and correlations with airway physiology.

RESULTS

Pairwise analysis of protein abundance in BALF pre- vs post-SBP-Ag revealed that 55 proteins were upregulated and 103 proteins were downregulated. We observed enrichment of groups of proteins mapping to hemostasis/fibrin clot, platelet activation, lipoprotein assembly, neutrophil degranulation proteins, and acute-phase inflammation-airway remodeling pathways. The abundances of F2 and Fibrinogen γ (FGG) correlated with eosinophil numbers, whereas SERPINA3 negatively correlated with change in FeNO. The coagulation proteins F2 and KNG negatively correlated with FN1 an index of airway remodeling. Interestingly, patients with lower FEV1 showed distinct allergen-induced patterns of 8 BALF proteins, including MUC1, alarmins (HSPB1), and actin polymerization factors.

CONCLUSIONS

Protein abundance of the fibrin formation cascade, platelet activation and remodeling are associated with late-phase leukocyte numbers and markers of remodeling. Patients with lower FEV1 have distinct dynamic responses to allergen.

PM2.5 Exposure and Asthma Development: The Key Role of Oxidative Stress

Oxidative stress is defined as the imbalance between reactive oxygen species (ROS) production and the endogenous antioxidant defense system, leading to cellular damage. Asthma is a common chronic inflammatory airway disease. The presence of asthma tends to increase the production of reactive oxygen species (ROS), and the antioxidant system in the lungs is insufficient to mitigate it. Therefore, asthma can lead to an exacerbation of airway hyperresponsiveness and airway inflammation. PM2.5 exposure increases ROS levels. Meanwhile, the accumulation of ROS will further enhance the oxidative stress response, resulting in DNA, protein, lipid, and other cellular and molecular damage, leading to respiratory diseases. An in-depth study on the relationship between oxidative stress and PM2.5-related asthma is helpful to understand the pathogenesis and progression of the disease and provides a new direction for the treatment of the disease. This paper reviews the research progress of oxidative stress in PM2.5-induced asthma as well as highlights the therapeutic potentials of antioxidant approaches in treatment of asthma.

Role of IL-18-transformed CD274-expressing eosinophils in promoting airway obstruction in experimental asthma

BACKGROUND

IL-5-dependent residential and IL-18-transformed pathogenic eosinophils have been reported; however, the role of IL-18-transformed CD274-expressing pathogenic eosinophils compared to IL-5-generated eosinophils in promoting airway obstruction in asthma has not yet been examined.

METHODS

Eosinophils are detected by tissue anti-MBP and anti-EPX immunostaining, CD274 expression by flow cytometry, and airway resistance using the Buxco FinePointe RC system.

RESULTS

We show that A. fumigatus-challenged wild-type mice, and different gene-deficient mice including naïve CC10-IL-18-transgenic mice, accumulate mostly peribronchial and perivascular CD274-expressing eosinophils except naïve CD2-IL-5-transgenic mice. Additionally, we show that CD2-IL-5 transgenic mice following rIL-18 treatment accumulate high number of CD274-expressing perivascular and peribronchial eosinophils with induced collagen, goblet cell hyperplasia and airway resistance compared to saline-challenged CD2-IL5 transgenic mice. Furthermore, we also show that even A. fumigatus-challenged IL-5 ^-/- mice and rIL-18 given ΔdblGATA mice accumulate CD274-expressing eosinophil-associated asthma pathogenesis including airway obstruction. Most importantly, we provide evidence that neutralization of CD274 and IL-18 in A. fumigatus-challenged mice ameliorate experimental asthma. Taken together, the data presented are clinically significant in establishing that anti-IL-18 neutralization is a novel immunotherapy to restrict asthma pathogenesis.

CONCLUSIONS

We demonstrate that IL-18 is critical for inducing asthma pathogenesis, and neutralization of CD274 is a potential immunotherapeutic strategy for asthma.

Sphingosine-1-phosphate/TGF-β axis drives epithelial mesenchymal transition in asthma-like disease

BACKGROUND AND PURPOSE

Airway remodelling is a critical feature of chronic lung diseases. Epithelial-mesenchymal transition (EMT) represents an important source of myofibroblasts, contributing to airway remodelling. Here, we investigated the sphingosine-1-phosphate (S1P) role in EMT and its involvement in asthma-related airway dysfunction.

EXPERIMENTAL APPROACH

A549 cells were used to assess the S1P effect on EMT and its interaction with TGF-β signalling. To assess the S1P role in vivo and its impact on lung function, two experimental models of asthma were used by exposing BALB/c mice to subcutaneous administration of either S1P or ovalbumin (OVA).

KEY RESULTS

Following incubation with TGF-β or S1P, A549 acquire a fibroblast-like morphology associated with an increase of mesenchymal markers and down-regulation of the epithelial. These effects are reversed by treatment with the TGF-β receptor antagonist LY2109761. Systemic administration of S1P to BALB/c mice induces asthma-like disease characterized by mucous cell metaplasia and increased levels of TGF-β, IL-33 and FGF-2 within the lung. The bronchi harvested from S1P-treated mice display bronchial hyperresponsiveness associated with overexpression of the mesenchymal and fibrosis markers and reduction of the epithelial.The S1P-induced switch from the epithelial toward the mesenchymal pattern correlates to a significant increase of lung resistance and fibroblast activation. TGF-β blockade, in S1P-treated mice, abrogates these effects. Finally, inhibition of sphingosine kinases by SK1-II in OVA-sensitized mice, abrogates EMT, pulmonary TGF-β up-regulation, fibroblasts recruitment and airway hyperresponsiveness.

CONCLUSION AND IMPLICATIONS

Targeting S1P/TGF-β axis may hold promise as a feasible therapeutic target to control airway dysfunction in asthma.

Photobiomodulation Therapy Restores IL-10 Secretion in a Murine Model of Chronic Asthma: Relevance to the Population of CD4+CD25+Foxp3+ Cells in Lung

It is largely known that photobiomodulation (PBM) has beneficial effects on allergic pulmonary inflammation. Our previous study showed an anti-inflammatory effect of the PBM in an acute experimental model of asthma, and we see that this mechanism is partly dependent on IL-10. However, it remains unclear whether the activation of regulatory T cells is mediated by PBM in a chronic experimental model of asthma. In this sense, the objective of this study was to verify the anti-inflammatory role of the PBM in the pulmonary inflammatory response in a chronic experimental asthma model. The protocol used for asthma induction was the administration of OVA subcutaneously (days 0 and 14) and intranasally (3 times/week, for 5 weeks). On day 50, the animals were sacrificed for the evaluation of the different parameters. The PBM used was the diode, with a wavelength of 660 nm, a power of 100 mW, and 5 J for 50 s/point, in three different application points. Our results showed that PBM decreases macrophages, neutrophils, and lymphocytes in the bronchoalveolar lavage fluid (BALF). Moreover, PBM decreased the release of cytokines by the lung, mucus, and collagen in the airways and pulmonary mechanics. When we analyzed the percentage of Treg cells in the group irradiated with laser, we verified an increase in these cells, as well as the release of IL-10 in the BALF. Therefore, we conclude that the use of PBM therapy in chronic airway inflammation attenuated the inflammatory process, as well as the pulmonary functional and structural parameters, probably due to an increase in Treg cells.

Role of amygdala in stress-induced upregulation of airway IL-1 signaling in asthma

Psychological stress, an important contributor to asthma morbidity, potentiates the immune response to allergen, but the brain mechanisms mediating this response are not fully understood. The amygdala is likely to play an important role, given its sensitivity to threat and connectivity with descending immune modulatory pathways. In this study, we recruited thirty asthmatic participants and examined glucose metabolism in the amygdala, using [F-18]fluorodeoxyglucose positron emission tomography, during a laboratory stressor. Stress hormone and airway inflammatory measurements were also acquired. Results showed that activity in the amygdala was significantly increased during the stressor, compared to a matched control task (p < .05 corrected). Moreover, the increase in amygdala activity was associated with a greater increase in sputum IL-1R1 mRNA and alpha amylase response (p < .05 corrected), which were also positively correlated (p = .01). These findings suggest that heightened amygdala reactivity may contribute to asthma morbidity via descending proinflammatory sympathetic signaling pathways.

Long-term modulation of airway remodelling in severe asthma following bronchial thermoplasty

Rationale

Bronchial thermoplasty is a mechanical therapeutic intervention that has been advocated as an effective treatment option for severe asthma. The mechanism is promoted as being related to the attenuation of airway smooth muscle which has been shown to occur in the short-term. However, long-term studies of the effects of bronchial thermoplasty on airway remodelling are few, with only limited assessment of airway remodelling indices.

Objectives

To evaluate the effect of bronchial thermoplasty on 1) airway epithelial and smooth muscle cells in culture and 2) airway remodelling in patients with severe asthma who have been prescribed bronchial thermoplasty up to 12 months post-treatment.

Methods

The distribution of heat within the airway by bronchial thermoplasty was assessed in a porcine model. Culture of human airway smooth muscle cells and bronchial epithelial cells evaluated the impact of thermal injury. Histological evaluation and morphometric assessment were performed on bronchial biopsies obtained from severe asthma patients at baseline, 6 weeks and 12 months following bronchial thermoplasty.

Results

Bronchial thermoplasty resulted in heterogeneous heating of the airway wall. Airway smooth muscle cell cultures sustained thermal injury, whilst bronchial epithelial cells were relatively resistant to heat. Airway smooth muscle and neural bundles were significantly reduced at 6 weeks and 12 months post-treatment. At 6 weeks post-treatment, submucosal collagen was reduced and vessel density increased, with both indices returning to baseline at 12 months. Goblet cell numbers, submucosal gland area and sub-basement membrane thickness were not significantly altered at any time point examined.

Conclusions

Bronchial thermoplasty primarily affects airway smooth muscle and nerves with the effects still present at 12 months post-treatment.

Role of Secretoglobin+ (club cell) NFκB/RelA-TGFβ signaling in aero-allergen-induced epithelial plasticity and subepithelial myofibroblast transdifferentiation

Repetitive aeroallergen exposure is linked to sensitization and airway remodeling through incompletely understood mechanisms. In this study, we examine the dynamic mucosal response to cat dander extract (CDE), a ubiquitous aero-allergen linked to remodeling, sensitization and asthma. We find that daily exposure of CDE in naïve C57BL/6 mice activates innate neutrophilic inflammation followed by transition to a lymphocytic response associated with waves of mucosal transforming growth factor (TGF) isoform expression. In parallel, enhanced bronchiolar Smad3 expression and accumulation of phospho-SMAD3 was observed, indicating paracrine activation of canonical TGFβR signaling. CDE exposure similarly triggered epithelial cell plasticity, associated with expression of mesenchymal regulatory factors (Snai1 and Zeb1), reduction of epithelial markers (Cdh1) and activation of the NFκB/RelA transcriptional activator. To determine whether NFκB functionally mediates CDE-induced growth factor response, mice were stimulated with CDE in the absence or presence of a selective IKK inhibitor. IKK inhibition substantially reduced the level of CDE-induced TGFβ1 expression, pSMAD3 accumulation, Snai1 and Zeb1 expression. Activation of epithelial plasticity was demonstrated by flow cytometry in whole lung homogenates, where CDE induces accumulation of SMA⁺Epcam⁺ population. Club cells are important sources of cytokine and growth factor production. To determine whether Club cell innate signaling through NFκB/RelA mediated CDE induced TGFβ signaling, we depleted RelA in Secretoglobin (Scgb1a1)-expressing bronchiolar cells. Immunofluorescence-optical clearing light sheet microscopy showed a punctate distribution of Scgb1a1 progenitors throughout the small airway. We found that RelA depletion in Secretoglobin⁺ cells results in inhibition of the mucosal TGFβ response, blockade of EMT and reduced subepithelial myofibroblast expansion. We conclude that the Secretoglobin—derived bronchiolar cell is central to coordinating the innate response required for mucosal TGFβ1 response, EMT and myofibroblast expansion. These data have important mechanistic implications for how aero-allergens trigger mucosal injury response and remodeling in the small airway.

Matricellular Protein Periostin Promotes Pericyte Migration in Fibrotic Airways

Introduction: Periostin is a matricellular protein that is currently used as a biomarker for asthma. However, its contribution to tissue remodeling in allergic asthma is currently unknown. We have previously demonstrated that tissue-resident mesenchymal stem cells known as pericytes are a key cell type involved in airway remodeling. This is thought to be caused the uncoupling of pericytes from the microvasculature supporting the large airways, facilitated by inflammatory growth factors and cytokines. It is hypothesized that periostin may be produced by profibrotic pericytes and contribute to the remodeling observed in allergic asthma. Methods: Lung sections from mice with allergic airway disease driven by exposure to house dust mite (HDM) were stained using an anti-periostin antibody to explore its involvement in fibrotic lung disease. Human pericytes were cultured in vitro and stained for periostin to assess periostin expression. Migration assays were performed using human pericytes that were pretreated with TGF-β or periostin. ELISAs were also carried out to assess periostin expression levels in bronchoalveolar lavage fluid as well as the induction of periostin production by IL-13. Results: Immunostaining indicated that pericytes robustly express periostin, with increased expression following treatment with TGF-β. Migration assays demonstrated that pericytes treated with periostin were more migratory. Periostin production was also increased in HDM exposed mice as well as in cultured pericytes treated with IL-13. Conclusion: Periostin is produced by pericytes in response to TGF-β or IL-13, and periostin plays a key role in inducing pericyte migration. The increase in periostin expression in TGF-β or IL-13 treated pericytes suggests that IL-13 may trigger periostin production in pericytes whilst TGF-β modulates periostin expression to promote pericyte migration in the context of tissue fibrosis.

Schisandrin B Attenuates Airway Inflammation and Airway Remodeling in Asthma by Inhibiting NLRP3 Inflammasome Activation and Reducing Pyroptosis

Asthma is a chronic inflammatory disorder of the airways. Schisandrin B (SB) is the main effective component. This study investigated the effects of SB on airway inflammation and airway remodeling in asthma. The rat model of asthma was established. The rats were treated with SB to evaluate the effects of SB on airway inflammation, airway remodeling, NLRP3 inflammasome activation, and pyroptosis. Alveolar macrophages of rats were isolated, and the macrophage inflammatory model was established by lipopolysaccharide (LPS) induction. The LPS-induced macrophages were treated with SB. The binding relationship between miR-135a-5p and TPRC1 was analyzed. LPS + SB-treated macrophages were transfected with miR-135a-5p inhibitor. The expressions of key factors of the STAT3/NF-κB pathway were detected. SB reduced airway inflammation and airway remodeling in asthmatic rats. SB inhibited NLRP3 inflammasome activation and reduced pyroptosis in asthmatic rats and LPS-induced macrophages. SB reversely regulated the miR-135a-5p/TRPC1 axis. Downregulation of miR-135a-5p attenuated the inhibitory effect of SB on NLRP3 inflammasome activation. SB inhibited the STAT3/NF-κB pathway via the miR-135a-5p/TRPC1 axis. In conclusion, SB inhibited NLRP3 inflammasome activation and reduced pyroptosis via the miR-135a-5p/TRPC1/STAT3/NF-κB axis, thus alleviating airway inflammation and airway remodeling in asthma. This study may confer novel insights for the management of asthma.

Nasal polyp fibroblasts (NPFs)-derived exosomes are important for the release of vascular endothelial growth factor from cocultured eosinophils and NPFs

OBJECTIVE

Significant eosinophil infiltration and tissue remodeling are common characteristics of conditions associated with chronic airway inflammation, such as chronic rhinosinusitis with nasal polyp and bronchial asthma. This study was designed to elucidate the role of eosinophil-fibroblast interactions in tissue remodeling during chronic airway inflammation.

METHODS

Peripheral blood eosinophils or EoL-1 eosinophilic leukemia cells were cocultured with nasal polyp fibroblasts (NPFs). Coculture-induced release of exosomes, major components of extracellular vesicles (EVs), and a profibrotic cytokine, vascular endothelial growth factor (VEGF), were evaluated by enzyme-linked immunosorbent assay.

RESULTS

Eosinophil-NPF interactions stimulated the release of exosomes and VEGF into culture supernatants. Coculture-induced release of exosomes was stimulated earlier than VEGF release, at 3 h of incubation. The average size of the EVs released by NPFs was 133 ± 3.6 nm. NPF-derived EVs (exosome concentration: 25 pg/mL) significantly stimulated VEGF release from EoL-1 cells. Pretreatment of NPFs with exosome inhibitor, GW4869 or DMA attenuated the release of exosomes and VEGF from cocultured EoL-1 cells and NPFs.

CONCLUSION

The results of this study indicate that eosinophil-fibroblast interactions are important in the pathophysiology of tissue remodeling in eosinophil-predominant airway inflammation and that NPF-derived exosomes play a crucial role in the release of VEGF.

Role of miR-185-5p as modulator of periostin synthesis and smooth muscle contraction in asthma

Asthma is a chronic respiratory disease produced by an aberrant immune response that originates with breathing difficulties and cough, through airway remodeling. The above pathophysiological events of asthma emerge the regulators of effectors, like epigenetics, which include microRNAs (miRNAs) who perform post‐transcriptional regulation, controlling diverse pathways in respiratory diseases. The objective of the study was to determine how miR‐185‐5p regulates the secretion of periostin by airway structural cells, and smooth muscle cells contraction, both related to airway remodeling in asthma. We used miR‐185‐5p mimic and inhibitors in bronchial smooth muscle cells (BSMCs) and small airway epithelial cells (SAECs) from healthy subjects. Gene expression and protein levels of periostin (POSTN), CDC42, and RHOA were analyzed by RT‐PCR and ELISA/Western blot, respectively. BSMC contractility was analyzed using cell‐embedded collagen gels and measurement of intracellular calcium was performed using Fura‐2. Additionally, miR‐185‐5p and periostin expression were evaluated in sputum from healthy and asthmatics. From these experiments, we observed that miR‐185‐5p modulation regulates periostin mRNA and protein in BSMCs and SAECs. A tendency for diminished miR‐185‐5p expression and higher periostin levels was seen in sputum cells from asthmatics compared to healthy, with an inverse correlation observed between POSTN and miR‐185‐5p. Inhibition of miR‐185‐5p produced higher BSMCs contraction induced by histamine. Calcium mobilization was not modified by miR‐185‐5p, showing that miR‐185‐5p role in BSMC contractility is performed by regulating CDC42 and RhoA pro‐contractile factors instead. In conclusion, miR‐185‐5p is a modulator of periostin secretion by airway structural cells and of smooth muscle contraction, which can be related to asthma pathophysiology, and thus, might be a promising therapeutic target.

Pathogenesis, clinical features of asthma COPD overlap (ACO), and therapeutic modalities

Both asthma and COPD are heterogeneous diseases identified by characteristic symptoms and functional abnormalities, with airway obstruction common in both diseases. Asthma COPD overlap (ACO) does not define a single disease but is a descriptive term for clinical use that includes several overlapping clinical phenotypes of chronic airways disease with different underlying mechanisms. This literature review was initiated to describe published studies, identify gaps in knowledge, and propose future research goals regarding the disease pathology of ACO, especially the airway remodelling changes and inflammation aspects. Airway remodelling occurs in asthma and COPD, but there are differences in the structures affected and the prime anatomic site at which they occur. Reticular basement membrane thickening and cellular infiltration with eosinophils and T-helper (CD4+) lymphocytes are prominent features of asthma. Epithelial squamous metaplasia, airway wall fibrosis, emphysema, bronchoalveolar lavage (BAL) neutrophilia and (CD8+) T-cytotoxic lymphocyte infiltrations in the airway wall are features of COPD. There is no universally accepted definition of ACO, nor are there clearly defined pathological characteristics to differentiate from asthma and COPD. Understanding etiological concepts within the purview of inflammation and airway remodelling changes in ACO would allow better management of these patients.