Transforming Growth Factor β1 Function in Airway Remodeling and Hyperresponsiveness. The Missing Link?

Functional analysis of airway remodeling is related with fibrotic mediators in asthmatic children

BACKGROUND

Asthmatic children present variable degrees of airway inflammation, remodeling, and resistance, which correlate with disease control and severity. The chronic inflammatory process of the airway triggers airway remodeling, which reflects the degree of airway resistance. Pro-inflammatory and pro-fibrotic mediators are centrally involved in this process.

OBJECTIVE

To investigate whether the levels of pulmonary and systemic pro-inflammatory and pro-fibrotic mediators present a correlation with the resistance of the respiratory system and of the proximal and distal airways.

METHODS

39 Asthmatic children (persistent mild and moderate) and 39 non-asthmatic children (both between 6 and 13 years old) were evaluated for anthropometric characteristics, lung function and mechanics, and pulmonary and systemic immune responses.

RESULTS

Asthmatic children showed an increased number of blood eosinophils (p < 0.04), basophils (p < 0.04), monocytes (p < 0.002) and lymphocytes (p < 0.03). In addition, asthmatic children showed impaired lung function, as demonstrated by FEV1 (p < 0.0005) and FEV1/FVC (p < 0.004), decreased total resistance of the respiratory system (R5Hz; p < 0.009), increased resistance of the proximal airways (R20Hz; p < 0.02), increased elastance (Z5Hz; p < 0.02) and increased reactance (X5Hz; p < 0.002) compared to non-asthmatic children. Moreover, the following inflammatory factors were significantly higher in asthmatic than non-asthmatic children: GM-CSF in the breath condensate (BC) (p < 0.0001) and in the serum (p < 0.0001); TGF-beta in the BC (p < 0.0001) and in the serum (p < 0.004); IL-5 in the BC (p < 0.02) and in the serum (p < 0.01); IL-4 in the serum (p < 0.0002).

CONCLUSIONS

Impulse oscillometry is a sensitive method to detect airway resistance in persistent mild and moderate asthmatic children, an event followed by increased levels of pro-inflammatory and pro-fibrotic mediators.

Effect of curcumin nanoparticles on proliferation and migration of mouse airway smooth muscle cells and airway inflammatory infiltration

Curcumin (CUR) possesses the capability to inhibit various inflammatory factors, exert anti-inflammatory effects, and alleviate asthma attacks; however, its hydrophobicity and instability significantly impede its clinical application. In this study, we synthesized CUR-loaded nanoparticles (CUR-NPs) and evaluated their impact on the proliferation, migration, and inflammatory infiltration of mouse airway smooth muscle cells (ASMCs), while investigating their underlying mechanisms. To achieve this objective, ASMCs were isolated from BALB/c mice and subjected to TGF-β1-induced cell proliferation and migration. Our findings demonstrate that CUR-NPs effectively regulate the release of CUR within cells with superior intracellular uptake compared to free CUR. The CCK-8 assay results indicate that the blank carrier does not exhibit any cytotoxic effects on cells, thus rendering the impact of the carrier itself negligible. The TGF-β1 group exhibited a significant increase in cell proliferation, whereas treatment with CUR-NPs significantly suppressed TGF-β1-induced cell proliferation. The findings from both the cell scratch assay and transwell assay demonstrated that TGF-β1 substantially enhanced cell migration, while CUR-NPs treatment effectively attenuated TGF-β1-induced cell migration. The Western blot analysis demonstrated a substantial increase in the expression levels of TGF-β1, p-STAT3, and CTGF in ASMCs following treatment with TGF-β1 when compared to the control group. Nevertheless, this effect was effectively counteracted upon administration of CUR-NPs. Furthermore, an asthma mouse model was successfully established and CUR-NPs were administered through tail vein injection. The serum levels of TGF-β1 and the expression levels of TGF-β1, p-STAT3, and CTGF proteins in the lung tissue of mice in the model group exhibited significant increases compared to those in the control group. However, CUR-NPs treatment effectively attenuated this change. Our research findings suggest that CUR-NPs possess inhibitory effects on ASMC proliferation, migration, and inflammatory infiltration by suppressing activation of the TGF-β1/p-STAT3/CTGF signaling pathway, thereby facilitating inhibition of airway remodeling.

Role of mechanoregulation in mast cell-mediated immune inflammation of the smooth muscle in the pathophysiology of esophageal motility disorders

Major esophageal disorders involve obstructive transport of bolus to the stomach, causing symptoms of dysphagia and impaired clearing of the refluxed gastric contents. These may occur due to mechanical constriction of the esophageal lumen or loss of relaxation associated with deglutitive inhibition, as in achalasia-like disorders. Recently, immune inflammation has been identified as an important cause of esophageal strictures and the loss of inhibitory neurotransmission. These disorders are also associated with smooth muscle hypertrophy and hypercontractility, whose cause is unknown. This review investigated immune inflammation in the causation of smooth muscle changes in obstructive esophageal bolus transport. Findings suggest that smooth muscle hypertrophy occurs above the obstruction and is due to mechanical stress on the smooth muscles. The mechanostressed smooth muscles release cytokines and other molecules that may recruit and microlocalize mast cells to smooth muscle bundles, so that their products may have a close bidirectional effect on each other. Acting in a paracrine fashion, the inflammatory cytokines induce genetic and epigenetic changes in the smooth muscles, leading to smooth muscle hypercontractility, hypertrophy, and impaired relaxation. These changes may worsen difficulty in the esophageal transport. Immune processes differ in the first phase of obstructive bolus transport, and the second phase of muscle hypertrophy and hypercontractility. Moreover, changes in the type of mechanical stress may change immune response and effect on smooth muscles. Understanding immune signaling in causes of obstructive bolus transport, type of mechanical stress, and associated smooth muscle changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.NEW & NOTEWORTHY Esophageal disorders such as esophageal stricture or achalasia, and diffuse esophageal spasm are associated with smooth muscle hypertrophy and hypercontractility, above the obstruction, yet the cause of such changes is unknown. This review suggests that smooth muscle obstructive disorders may cause mechanical stress on smooth muscle, which then secretes chemicals that recruit, microlocalize, and activate mast cells to initiate immune inflammation, producing functional and structural changes in smooth muscles. Understanding the immune signaling in these changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.

Mast Cells in Aspirin-Exacerbated Respiratory Disease

PURPOSE OF REVIEW

Aspirin-exacerbated respiratory disease (AERD) is a syndrome of high type 2 inflammation and is known to critically involve mast cell activation. The mast cell is an important cell in the baseline inflammatory processes in the upper and lower airway by maintaining and amplifying type 2 inflammation. But it also is prominent in the hypersensitivity reaction to COX-1 inhibition which defines this condition.

RECENT FINDINGS

Recent work highlights the mast cell as a focal point in AERD pathogenesis. Using AERD as a specific model of both high type 2 asthma and chronic sinusitis, the role of mast cell activity can be better understood in other aspects of airway inflammation. Further dissecting out the mechanism of COX-1-mediated mast cell activation in AERD will be an important next phase in our understanding of NSAID-induced hypersensitivity as well as AERD pathophysiology.

Obesity and Insulin Resistance in Asthma Pathogenesis and Clinical Outcomes

Common inflammatory ground links obesity, insulin resistance, and asthma. As recognition of their interplay, one worsening the natural course of the other, is recognised, questions remain about how to adequately address them altogether to improve clinical outcomes. The present manuscript sheds light on the problem, describing possible pathophysiological links, clinical views, and therapeutic challenges, raising questions about what remains to be done, and calling for multidisciplinary treatment of these patients to detect diseases early and adequately address them before they become full-blown and deteriorate their health and quality of life.

Airways Type-2 Related Disorders: Multiorgan, Systemic or Syndemic Disease?

Chronic rhinosinusitis (CRS) has recently undergone a significant paradigm shift, moving from a phenotypical classification towards an "endotype-based" definition that places more emphasis on clinical and therapeutic aspects. Similar to other airway diseases, like asthma, most cases of CRS in developed countries exhibit a dysregulated type-2 immune response and related cytokines. Consequently, the traditional distinction between upper and lower airways has been replaced by a "united airway" perspective. Additionally, type-2 related disorders extend beyond respiratory boundaries, encompassing conditions beyond the airways, such as atopic dermatitis. This necessitates a multidisciplinary approach. Moreover, consideration of possible systemic implications is crucial, particularly in relation to sleep-related breathing diseases like Obstructive Sleep Apnoea Syndrome (OSAS) and the alteration of systemic inflammatory mediators such as nitric oxide. The trends in epidemiological, economic, and social burden are progressively increasing worldwide, indicating syndemic characteristics. In light of these insights, this narrative review aims to present the latest evidence on respiratory type-2 related disorders, with a specific focus on CRS while promoting a comprehensive perspective on the "united airways". It also introduces a novel concept: viewing these conditions as a multiorgan, systemic, and syndemic disease.

Sputum Transcriptomics Reveals FCN1+ Macrophage Activation in Mild Eosinophilic Asthma Compared to Non-Asthmatic Eosinophilic Bronchitis

PURPOSE

Eosinophilic asthma (EA) and non-asthmatic eosinophilic bronchitis (EB) share similar eosinophilic airway inflammation. Unlike EA, EB did not present airway hyperresponsiveness or airflow obstruction. We aimed to compare the mechanism underlying the different manifestations between EA and EB via sputum transcriptomics analysis.

METHODS

Induced-sputum cells from newly physician-diagnosed EA, EB patients, and healthy controls (HCs) were collected for RNA sequencing.

RESULTS

Bulk RNA sequencing was performed using sputum cells from patients with EA (n = 18), EB (n = 15) and HCs (n = 28). Principal component analysis revealed similar gene expression patterns in EA and EB. The most differentially expressed genes in EB compared with HC were also shared by EA, including IL4, IL5 IL13, CLC, CPA3, and DNASE1L3. However, gene set enrichment analysis showed that the signatures regulating macrophage activation were enriched in EA compared to EB. Sputum cells were profiled using single-cell RNA sequencing. FABP4+ macrophages, SPP1+ macrophages, FCN1+ macrophages, dendritic cells, T cells, B cells, mast cells, and epithelial cells were identified based on gene expression profiling. Analysis of cell-cell communication revealed that interactions between FCN1+ macrophages and other cells were higher in EA than in EB. A wealth of transforming growth factor beta (TGF-β) and vascular endothelial growth factor (VEGF) interactions between FCN1+ macrophages and other cells have been shown in EA. The gene expression levels of EREG, TGFBI, and VEGFA in FCN1+ macrophages of EA were significantly higher than those of EB. Furthermore, signatures associated with the response to TGF-β, cellular response to VEGF stimulus and developmental cell growth were enriched in FCN1+ macrophages of EA compared to those of EB.

CONCLUSIONS

FCN1+ macrophage activation associated with airway remodeling processes was upregulated in EA compared to that in EB, which may contribute to airway hyperresponsiveness and airflow obstruction.

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.

Role of SYVN1 in the control of airway remodeling in asthma protection by promoting SIRT2 ubiquitination and degradation

BACKGROUND

Asthma is a heterogenous disease that characterized by airway remodeling. SYVN1 (Synoviolin 1) acts as an E3 ligase to mediate the suppression of endoplasmic reticulum (ER) stress through ubiquitination and degradation. However, the role of SYVN1 in the pathogenesis of asthma is unclear.

RESULTS

In the present study, an ovalbumin (OVA)-induced murine model was used to evaluate the effect of SYVN1 on asthma. An increase in SYVN1 expression was observed in the lungs of mice after OVA induction. Overexpression of SYVN1 attenuated airway inflammation, goblet cell hyperplasia and collagen deposition induced by OVA. The increased ER stress-related proteins and altered epithelial-mesenchymal transition (EMT) markers were also inhibited by SYVN1 in vivo. Next, TGF-β1-induced bronchial epithelial cells (BEAS-2B) were used to induce EMT process in vitro. Results showed that TGF-β1 stimulation downregulated the expression of SYVN1, and SYVN1 overexpression prevented ER stress response and EMT process in TGF-β1-induced cells. In addition, we identified that SYVN1 bound to SIRT2 and promoted its ubiquitination and degradation. SIRT2 overexpression abrogated the protection of SYVN1 on ER stress and EMT in vitro.

CONCLUSIONS

These data suggest that SYVN1 suppresses ER stress through the ubiquitination and degradation of SIRT2 to block EMT process, thereby protecting against airway remodeling in asthma.

m6A-modified miR-143-3p inhibits epithelial mesenchymal transition in bronchial epithelial cells and extracellular matrix production in lung fibroblasts by targeting Smad3

BACKGROUND

Airway epithelial cells epithelial mesenchymal transition (EMT) and lung fibroblasts extracellular matrix (ECM) production are the key steps in airway remodeling. Our previous study demonstrated that miR-143-3p has the ability to impede airway smooth muscle cell proliferation and ECM deposition. However, the function of miR-143-3p in airway epithelial cells and lung fibroblasts remains unclear.

METHODS

Cell viability was determined using MTT method, while cell migration was evaluated through scratch assay. EMT and ECM proteins were detected by western blot, RT-qPCR, and ELISA. To determine the level of miR-143-3p m6A methylation, we employed the meRIP-qPCR assay. Additionally, the binding of miR-143-3p with Smad3 were projected by bioinformatics and validated by dual luciferase reporter assays.

RESULTS

It was discovered that the expression of miR-143-3p were lower in both asthma patients and TGF-β1-treated human bronchial epithelial 16HBE cells and human lung fibroblast HPF cells. Upregulation of miR-143-3p restrained 16HBE cell migration, and decreased EMT mesenchymal markers and increased epithelial markers. And upregulation of miR-143-3p impaired cell viability and ECM protein production in HPF cells. Mechanistically, interfering with METTL3 resulted in decreased m6A modification of miR-143-3p and led to lower levels of miR-143-3p. Moreover, miR-143-3p were verified to directly target and downregulate Smad3. Upregulation of Smad3 attenuated the effects of miR-143-3p on cell EMT and ECM production.

CONCLUSION

MiR-143-3p inhibits airway epithelial cell EMT as well as lung fibroblast ECM production by downregulating Smad3. Therefore, miR-143-3p may be a promising target to reduce airway remodeling in asthma.

Role of transforming growth factor-β in airway remodelling in bronchiolitis obliterans

Airway remodelling is the main pathological mechanism of bronchiolitis obliterans (BO). Several studies have found that transforming growth factor-β (TGF-β) expression is increased in BO during airway remodelling, where it plays an important role in various biological processes by binding to its receptor complex to activate multiple signalling proteins and pathways. This review examines the role of TGF-β in airway remodelling in BO and its potential as a therapeutic target, highlighting the mechanisms of TGF-β activation and signalling, cellular targets of TGF-β actions, and research progress in TGF-β signalling and TGF-β-mediated processes.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Proline is increased in allergic asthma and promotes airway remodeling

Proline and its synthesis enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) are implicated in epithelial-mesenchymal transition (EMT), yet how proline and PYCR1 function in allergic asthmatic airway remodeling via EMT has not yet been addressed to our knowledge. In the present study, increased levels of plasma proline and PYCR1 were observed in patients with asthma. Similarly, proline and PYCR1 in lung tissues were high in a murine allergic asthma model induced by house dust mites (HDMs). Pycr1 knockout decreased proline in lung tissues, with reduced airway remodeling and EMT. Mechanistically, loss of Pycr1 restrained HDM-induced EMT by modulating mitochondrial fission, metabolic reprogramming, and the AKT/mTORC1 and WNT3a/β-catenin signaling pathways in airway epithelial cells. Therapeutic inhibition of PYCR1 in wild-type mice disrupted HDM-induced airway inflammation and remodeling. Deprivation of exogenous proline relieved HDM-induced airway remodeling to some extent. Collectively, this study illuminates that proline and PYCR1 involved with airway remodeling in allergic asthma could be viable targets for asthma treatment.

Rhinovirus infection induces secretion of endothelin-1 from airway epithelial cells in both in vitro and in vivo models

BACKGROUND

Rhinovirus (RV) infection of airway epithelial cells triggers asthma exacerbations, during which airway smooth muscle (ASM) excessively contracts. Due to ASM contraction, airway epithelial cells become mechanically compressed. We previously reported that compressed human bronchial epithelial (HBE) cells are a source of endothelin-1 (ET-1) that causes ASM contraction. Here, we hypothesized that epithelial sensing of RV by TLR3 and epithelial compression induce ET-1 secretion through a TGF-β receptor (TGFβR)-dependent mechanism.

METHODS

To test this, we used primary HBE cells well-differentiated in air-liquid interface culture and two mouse models (ovalbumin and house dust mite) of allergic airway disease (AAD). HBE cells were infected with RV-A16, treated with a TLR3 agonist (poly(I:C)), or exposed to compression. Thereafter, EDN1 (ET-1 protein-encoding gene) mRNA expression and secreted ET-1 protein were measured. We examined the role of TGFβR in ET-1 secretion using either a pharmacologic inhibitor of TGFβR or recombinant TGF-β1 protein. In the AAD mouse models, allergen-sensitized and allergen-challenged mice were subsequently infected with RV. We then measured ET-1 in bronchoalveolar lavage fluid (BALF) and airway hyperresponsiveness (AHR) following methacholine challenge.

RESULTS

Our data reveal that RV infection induced EDN1 expression and ET-1 secretion in HBE cells, potentially mediated by TLR3. TGFβR activation was partially required for ET-1 secretion, which was induced by RV, poly(I:C), or compression. TGFβR activation alone was sufficient to increase ET-1 secretion. In AAD mouse models, RV induced ET-1 secretion in BALF, which positively correlated with AHR.

CONCLUSIONS

Our data provide evidence that RV infection increased epithelial-cell ET-1 secretion through a TGFβR-dependent mechanism, which contributes to bronchoconstriction during RV-induced asthma exacerbations.

Mechanisms of airway epithelial injury and abnormal repair in asthma and COPD

The airway epithelium comprises of different cell types and acts as a physical barrier preventing pathogens, including inhaled particles and microbes, from entering the lungs. Goblet cells and submucosal glands produce mucus that traps pathogens, which are expelled from the respiratory tract by ciliated cells. Basal cells act as progenitor cells, differentiating into different epithelial cell types, to maintain homeostasis following injury. Adherens and tight junctions between cells maintain the epithelial barrier function and regulate the movement of molecules across it. In this review we discuss how abnormal epithelial structure and function, caused by chronic injury and abnormal repair, drives airway disease and specifically asthma and chronic obstructive pulmonary disease (COPD). In both diseases, inhaled allergens, pollutants and microbes disrupt junctional complexes and promote cell death, impairing the barrier function and leading to increased penetration of pathogens and a constant airway immune response. In asthma, the inflammatory response precipitates the epithelial injury and drives abnormal basal cell differentiation. This leads to reduced ciliated cells, goblet cell hyperplasia and increased epithelial mesenchymal transition, which contribute to impaired mucociliary clearance and airway remodelling. In COPD, chronic oxidative stress and inflammation trigger premature epithelial cell senescence, which contributes to loss of epithelial integrity and airway inflammation and remodelling. Increased numbers of basal cells showing deregulated differentiation, contributes to ciliary dysfunction and mucous hyperproduction in COPD airways. Defective antioxidant, antiviral and damage repair mechanisms, possibly due to genetic or epigenetic factors, may confer susceptibility to airway epithelial dysfunction in these diseases. The current evidence suggests that a constant cycle of injury and abnormal repair of the epithelium drives chronic airway inflammation and remodelling in asthma and COPD. Mechanistic understanding of injury susceptibility and damage response may lead to improved therapies for these diseases.

Quercetin Alleviates Asthma-Induced Airway Inflammation and Remodeling through Downregulating Periostin via Blocking TGF-β1/Smad Pathway

INTRODUCTION

The aim of the study was to discuss whether the anti-asthmatic effect of quercetin is related to periostin and the downstream molecular pathway of quercetin's anti-asthmatic effect.

METHODS

We constructed asthmatic mice, sensitized by ovalbumin, and administrated different treatments into mice according to the experimental design. In this study, we mainly observed the inflammatory response, airway fibrosis, and airway hyperresponsiveness in asthmatic mice. Pathological stains (H&E, PAS, and Masson) were performed. We also detected the inflammation factors and fibrosis-related cytokines by enzyme-linked immunosorbent serologic assay. In addition, we also explored the level of periostin by enzyme-linked immunosorbent serologic assay and Western blot. At the same time, TGF-β1/Smad pathway was also determined by Western blot.

RESULTS

A high expression of periostin was found in asthmatic mice, and quercetin decreases periostin content in bronchoalveolar lavage fluid. Quercetin and OC-20 inhibit airway inflammation response, airway fibrosis, and airway hyperreactivity. Quercetin downregulated TGF-β1/Smad pathway in the lung tissues of asthmatic mice. Anti-asthma role of quercetin is related to periostin. Then deeper mechanical study revealed that inhibiting TGF-β1 could improve asthmatic symptoms, and quercetin exerted the protective effect on asthmatic mice through inhibition of TGF-β1/Smad pathway.

CONCLUSION

Quercetin provided a protective role against asthma via periostin, manifested by mild inflammatory infiltration, reduced goblet cell proliferation, and reduced airway fibrosis. TGF-β1/Smad pathway is an important transduction system, participating in the protective effect of quercetin on asthma.

Targeting ATP12A, a Nongastric Proton Pump α Subunit, for Idiopathic Pulmonary Fibrosis Treatment

Idiopathic pulmonary fibrosis (IPF) is a pathological condition of unknown etiology that results from injury to the lung and an ensuing fibrotic response that leads to the thickening of the alveolar walls and obliteration of the alveolar space. The pathogenesis is not clear, and there are currently no effective therapies for IPF. Small airway disease and mucus accumulation are prominent features in IPF lungs, similar to cystic fibrosis lung disease. The ATP12A gene encodes the α-subunit of the nongastric H+, K+-ATPase, which functions to acidify the airway surface fluid and impairs mucociliary transport function in patients with cystic fibrosis. It is hypothesized that the ATP12A protein may play a role in the pathogenesis of IPF. The authors' studies demonstrate that ATP12A protein is overexpressed in distal small airways from the lungs of patients with IPF compared with normal human lungs. In addition, overexpression of the ATP12A protein in mouse lungs worsened bleomycin induced experimental pulmonary fibrosis. This was prevented by a potassium competitive proton pump blocker, vonoprazan. These data support the concept that the ATP12A protein plays an important role in the pathogenesis of lung fibrosis. Inhibition of the ATP12A protein has potential as a novel therapeutic strategy in IPF treatment.

Prophylactic and therapeutic potential of magnolol-loaded PLGA-PEG nanoparticles in a chronic murine model of allergic asthma

Magnolol is a chemically defined and active polyphenol extracted from magnolia plants possessing anti-allergic activity, but its low solubility and rapid metabolism dramatically hinder its clinical application. To improve the therapeutic effects, magnolol-encapsulated polymeric poly (DL-lactide-co-glycolide)-poly (ethylene glycol) (PLGA-PEG) nanoparticles were constructed and characterized. The prophylactic and therapeutic efficacy in a chronic murine model of OVA-induced asthma and the mechanisms were investigated. The results showed that administration of magnolol-loaded PLGA-PEG nanoparticles significantly reduced airway hyperresponsiveness, lung tissue eosinophil infiltration, and levels of IL-4, IL-13, TGF-β₁, IL-17A, and allergen-specific IgE and IgG₁ in OVA-exposed mice compared to their empty nanoparticles-treated mouse counterparts. Magnolol-loaded PLGA-PEG nanoparticles also significantly prevented mouse chronic allergic airway mucus overproduction and collagen deposition. Moreover, magnolol-encapsulated PLGA-PEG nanoparticles showed better therapeutic effects on suppressing allergen-induced airway hyperactivity, airway eosinophilic inflammation, airway collagen deposition, and airway mucus hypersecretion, as compared with magnolol-encapsulated poly (lactic-co-glycolic acid) (PLGA) nanoparticles or magnolol alone. These data demonstrate the protective effect of magnolol-loaded PLGA-PEG nanoparticles against the development of allergic phenotypes, implicating its potential usefulness for the asthma treatment.

Cell-contact-mediated assembly of contractile airway smooth muscle rings

Microtissues in the shape of toroidal rings provide an ideal geometry to better represent the structure and function of the airway smooth muscle present in the small airways, and to better understand diseases such as asthma. Here, polydimethylsiloxane devices consisting of a series of circular channels surrounding central mandrels are used to form microtissues in the shape of toroidal rings by way of the self-aggregation and -assembly of airway smooth muscle cell (ASMC) suspensions. Over time, the ASMCs present in the rings become spindle-shaped and axially align along the ring circumference. Ring strength and elastic modulus increase over 14 d in culture, without significant changes in ring size. Gene expression analysis indicates stable expression of mRNA for extracellular matrix-associated proteins, including collagen I and lamininsα1 andα4 over 21 d in culture. Cells within the rings respond to TGF-β1 treatment, leading to dramatic decreases in ring circumference, with increases in mRNA and protein levels for extracellular matrix and contraction-associated markers. These data demonstrate the utility of ASMC rings as a platform for modeling diseases of the small airways such as asthma.

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.

Current Perspective on the Role of the Circadian Clock and Extracellular Matrix in Chronic Lung Diseases

The circadian clock is a biochemical oscillator that rhythmically regulates physiological and behavioral processes such as inflammation, immunity, and metabolism in mammals. Circadian clock disruption is a key driver for chronic inflammatory as well as fibrotic lung diseases. While the mechanism of circadian clock regulation in the lung has been minimally explored, some evidence suggests that the transforming growth factor β (TGFβ) signaling pathway and subsequent extracellular matrix (ECM) accumulation in the lung may be controlled via a clock-dependent mechanism. Recent advancements in this area led us to believe that pharmacologically targeting the circadian clock molecules may be a novel therapeutic approach for treating chronic inflammatory lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). Here, we update the current perspective on the circadian clock role in TGFβ1 signaling and extracellular matrix production during chronic lung diseases.

MUC7 VNTR polymorphism and association with bronchial asthma in Egyptian children

Overproduction of mucins in the airways donates largely to airway blockage in asthma patients. Glycoprotein MUC7 plays a role in the clearance of bacteria and has anti-candidacidal criteria. Our goal was to investigate the association between the MUC7 variable number of tandem repeats (VNTR) polymorphism and bronchial asthma among Egyptian children. The MUC7 VNTR polymorphism was investigated among 100 children with bronchial asthma and 100 healthy controls using polymerase chain reaction (PCR) method. Serum levels of immunoglobulin E (IgE), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta1 (TGF-β1) were assessed by enzyme-linked immunosorbent assay (ELISA) technique. The frequencies of 6*5 genotype, 5*5 genotype, (6*5 + 5*5) genotypes, and MUC7*5 allele of the MUC7 VNTR variant were significantly lower among asthmatic patients than controls (p < 0.015, OR = 0.39, 95% CI = 0.19-0.81; p = 0.03, OR = 0.18, 95% CI = 0.04-0.86; p < 0.001, OR = 0.29, 95% CI = 0.15-0.58; p < 0.001, OR = 0.3, 95% CI = 0.17-0.55, respectively). The (6*5 + 5*5) genotypes of the MUC7 VNTR variant were not associated with the clinical manifestations and serum levels of IgE, TNF-α, and TGF-β1 among asthmatic patients (p ˃ 0.05). In conclusion, the (6*5 + 5*5) genotypes of the MUC7 VNTR variant may have a protective role for bronchial asthma in Egyptian children.

GARP Polymorphisms Associated with Susceptibility to House Dust Mite-Sensitized Persistent Allergic Rhinitis in a Chinese Population

Background

Genetic variants in GARP (also known as LRRC32) have been reported to have significant associations with asthma and eczema in special populations, but little is known about allergic rhinitis. This study purposes to evaluate the association of single nucleotide polymorphisms (SNPs) in GARP with house dust mite (HDM)-sensitized persistent allergic rhinitis (PER) in a population of Han Chinese.

Methods

In this hospital-based case–control study, 534 HDM-sensitized PER patients and 451 healthy controls were recruited from East China. In this population, six SNPs in GARP were identified. Serum total and specific IgE levels were measured with ImmunoCAP. Secondary structure and minimum free energy were predicted by RNAfold.

Results

rs79525962 was associated with the risk of HDM-sensitized PER (P < 0.05). The individuals with CT+TT genotype demonstrated a higher risk of HDM-sensitized PER than those with CC genotype (adjusted OR = 1.393, 95% CI = 1.019–1.904). The homozygous genotype CC of rs3781699 rendered a lower risk of HDM-sensitized PER than the wild-type genotype AA (adjusted OR = 0.646, 95% CI = 0.427–0.976); however, the genotype and allele frequencies of rs3781699 demonstrated no associations with HDM-sensitized PER (P > 0.05). rs79525962 increased the risk of HDM-sensitized PER in the subgroup aged ≥16 years (adjusted OR = 1.745, 95% CI = 1.103–2.760), and this high risk was also found in the females (adjusted OR = 1.708, 95% CI = 1.021–2.856). The G-C haplotype of rs1320646-rs3781699 rendered a lower risk of HDM-sensitized PER than the common haplotype G-A (adjusted OR = 0.819, 95% CI = 0.676–0.993). The secondary structure of GARP altered in response to different genotypes of rs79525962 and rs3781699.

Conclusion

SNP rs79525962 in the GARP gene marks a risk locus of HDM-sensitized PER in Chinese Hans.

BRD7 restrains TNF-α-induced proliferation and migration of airway smooth muscle cells by inhibiting notch signaling

Objective: Bromodomain-containing protein 7 (BRD7) is a key component of the switch/sucrose non-fermentable complex that participates in chromatin remodeling and transcriptional regulation. Although the emerging role of BRD7 in the pathophysiology of various diseases has been observed, its role in asthma remains unknown. Here, we assessed the function of BRD7 as a mediator of airway remodeling in asthma using an in vitro model. Methods: Airway smooth muscle cells (ASMCs) were challenged with tumor necrosis factor-α (TNF-α) to establish an in vitro airway remodeling model. Protein levels were examined using western blotting. Cell proliferation was measured using the cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell migration was assessed using a transwell migration assay. Results: Exposure to TNF-α dramatically decreased BRD7 levels in ASMCs. BRD7 remarkably decreased TNF-α-induced proliferation and migration of ASMCs. In contrast, ASMCs with BRD7 deficiency were more sensitive to TNF-α-induced pro-proliferative and pro-migratory effects. Mechanistically, BRD7 could repress the expression of Notch1 and block the Notch pathway in TNF-α-challenged cells. Notably, reactivation of Notch signaling substantially reversed the BRD7 overexpression-mediated effects, whereas restraining Notch signaling abolished BRD7-depletion-mediated effects on TNF-α-challenged cells. Conclusions: BRD7 inhibits the proliferation and migration of ASMCs elicited by TNF-α by downregulating the Notch pathway. This study indicates that BRD7 may exert a suppressive effect on airway remodeling during asthma.

Shenqihuatan formula reduces inflammation by inhibiting transforming growth factor-beta-stimulated signaling pathway in airway smooth muscle cells

OBJECTIVE

To study the effects and mechanism of Shenqihuatan formula (, SQHT) of the transforming growth factor-beta (TGF-β)-stimulated cell processes in airway remodeling.

METHODS

The current study examined cell viability using a Cell Counting Kit-8 assay. Furthermore, a Transwell assay was conducted to detect the ability of cell migration, and apoptosis was detected via flowcytometry. Western Blot and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the expression levels of apoptosis or inflammation-related factors, such as TGF-β, Interleukin-1β (IL-1β), B cell lymphoma 2 (Bcl-2), Bcl-2-Associated X (Bax), Ras homolog gene family, member A (RhoA), recombinant rho associated coiled coil containing protein kinase 1/2 (ROCK1/2), extracellular regulated protein kinases 1/2 (ERK1/2), Snail, and Slug. Finally, the expression levels of matrix metalloproteinase-9 (MMP-9) and Tissue inhibitor of metalloproteinase (TIMP-1) were admeasured by enzyme-linked immuno sorbent assay.

RESULTS

The results demonstrated that SQHT inhibited the viability and migration, as well as the the F-actin formation and cytoskeletal reorganization of airway smooth muscle cells (ASMCs) stimulated by TGF-β. By monitoring the changes of critical regulators in the presence of the formula, it was observed that the expression levels of TGF-β, IL-1β, Bcl-2, RhoA, ROCK1/2, ERK1/2, Snail, and Slug were markedly suppressed, whereas Bax expression exhibited the opposite effect. Compared with a well-characterized RhoA pathway inhibitor, Fasudil, SQHT generated equivalent or even higher inhibitory effects on these processes in ASMCs.

CONCLUSIONS

Collectively, these suggested that SQHT can reduce airway inflammation by inhibiting TGF-β-stimulated signaling pathways in ASMCs. These findings may provide a novel remedy for treating ASMC inflammation, which causes thickening and obstruction of the airway in chronic obstructive pulmonary disease.

Role of Respiratory Epithelial Cells in Allergic Diseases

The airway epithelium provides the first line of defense to the surrounding environment. However, dysfunctions of this physical barrier are frequently observed in allergic diseases, which are tightly connected with pro- or anti-inflammatory processes. When the epithelial cells are confronted with allergens or pathogens, specific response mechanisms are set in motion, which in homeostasis, lead to the elimination of the invaders and leave permanent traces on the respiratory epithelium. However, allergens can also cause damage in the sensitized organism, which can be ascribed to the excessive immune reactions. The tight interaction of epithelial cells of the upper and lower airways with local and systemic immune cells can leave an imprint that may mirror the pathophysiology. The interaction with effector T cells, along with the macrophages, play an important role in this response, as reflected in the gene expression profiles (transcriptomes) of the epithelial cells, as well as in the secretory pattern (secretomes). Further, the storage of information from past exposures as memories within discrete cell types may allow a tissue to inform and fundamentally alter its future responses. Recently, several lines of evidence have highlighted the contributions from myeloid cells, lymphoid cells, stromal cells, mast cells, and epithelial cells to the emerging concepts of inflammatory memory and trained immunity.

The Role of Osthole on TGF-β-Induced Lung Epithelium Apoptosis Injury and Epithelial-Mesenchymal Transition-Mediated Airway Remodeling in Pediatric Asthma

Osthole, a coumarin compound derived from Fructus Cnidii, exerts anti-inflammatory effects in an asthma model. But the effect of osthole on epithelial injury and epithelial-mesenchymal transition (EMT) in asthma remains unclear. 16HBE cells were incubated with TGF-β1 with or without osthole in vitro. Ovalbumin (OVA)-induced asthmatic mouse model was established in vivo. Cell counting kit-8 was carried out to evaluate the viability of 16HBE cells. The impact of osthole on TGF-β1-evoked cell apoptosis and EMT process was measured by flow cytometry based on Annexin V-FITC/PI staining, transwell assay, immunofluorescence, and Western blot. The regulatory role of osthole in TGF-β1/Smad and p38, ERK1/2, and JNK MAPK signaling was detected via Western blot. Osthole treatment significantly suppressed TGF-β1-induced 16HBE cell apoptosis, verified by a reduced percentage of apoptotic cells, decreased expression of proapoptotic proteins (cleaved-caspase3 and Bax), and enhanced antiapoptotic factor (Bcl-2) expression. In addition, the promotive impact of TGF-β1 on the migration of 16HBE cells was reversed by osthole, accompanied by elevated E-cadherin expression and reduced Snail and N-cadherin expression. The activation of the Smad2/3 and MAPKs pathway evoked by TGF-β1 was inhibited by osthole in 16HBE cells. We also found that osthole mitigated airway epithelium injury and subepithelial fibrosis in OVA-challenged asthmatic mice in vivo. Osthole could mitigate TGF-β1-induced epithelial cell injury and EMT process by suppressing the activation of MAPK and Smad2/3 pathways separately. Our present study showed a new insight into understanding the underlying mechanism of osthole injury on epithelium injury and subepithelial fibrosis in airway remodeling. Asthma, epithelial injury, epithelial-mesenchymal transition, and airway remodeling are the effects of osthole on airway remodeling.

Aspergillus fumigatus-Host Interactions Mediating Airway Wall Remodelling in Asthma

Asthma is a chronic heterogeneous respiratory condition that is mainly associated with sensitivity to airborne agents such as pollen, dust mite products and fungi. Key pathological features include increased airway inflammation and airway wall remodelling. In particular, goblet cell hyperplasia, combined with excess mucus secretion, impairs clearance of the inhaled foreign material. Furthermore, structural changes such as subepithelial fibrosis and increased smooth muscle hypertrophy collectively contribute to deteriorating airway function and possibility of exacerbations. Current pharmacological therapies focused on airway wall remodelling are limited, and as such, are an area of unmet clinical need. Sensitisation to the fungus, Aspergillus fumigatus, is associated with enhanced asthma severity, bronchiectasis, and hospitalisation. How Aspergillus fumigatus may drive airway structural changes is unclear, although recent evidence points to a central role of the airway epithelium. This review provides an overview of the airway pathology in patients with asthma and fungal sensitisation, summarises proposed airway epithelial cell-fungal interactions and discusses the initiation of a tissue remodelling response. Related findings from in vivo animal models are included given the limited analysis of airway pathology in patients. Lastly, an important role for Aspergillus fumigatus-derived proteases in triggering a cascade of damage-repair events through upregulation of airway epithelial-derived factors is proposed.

Asthma Phenotype with Metabolic Dysfunction

Asthma is chronic eosinophilic bronchitis with the dominancy of T helper 2 (Th2) inflammation. However, patients with asthma and metabolic dysfunction have pathogenic and pathological differences from those with Th2 inflammation. Metabolic dysfunction, typically presented as metabolic syndrome, has several important clinical components including central obesity, insulin resistance or glucose intolerance, dyslipidemia, and vitamin D deficiency. Data from large epidemiological studies support the significance of these components in the control of asthma and their contribution to airway remodeling, suggesting the presence of an asthma phenotype with metabolic dysfunction. These components are quite interactive with each other, so it is difficult to reveal the individual role of each. It is well known that asthma is difficult to treat in patients with obesity, due in part to inadequate response to inhaled corticosteroids. Additionally, vitamin D deficiency and insulin resistance have been regarded as aggravating factors of asthma control and airway remodeling. Recent clinical and in vivo studies have revealed the specific mechanisms of these components, which may aggravate asthma control and airway remodeling. In this review article, I summarize the recent studies and unmet needs for patients with asthma and metabolic dysfunction.

Role of Eosinophils in Intestinal Inflammation and Fibrosis in Inflammatory Bowel Disease: An Overlooked Villain?

Eosinophils are leukocytes which reside in the gastrointestinal tract under homeostatic conditions, except for the esophagus which is normally devoid of eosinophils. Research on eosinophils has primarily focused on anti-helminth responses and type 2 immune disorders. In contrast, the search for a role of eosinophils in chronic intestinal inflammation and fibrosis has been limited. With a shift in research focus from adaptive to innate immunity and the fact that the eosinophilic granules are filled with inflammatory mediators, eosinophils are becoming a point of interest in inflammatory bowel diseases. In the current review we summarize eosinophil characteristics and recruitment as well as the current knowledge on presence, inflammatory and pro-fibrotic functions of eosinophils in inflammatory bowel disease and other chronic inflammatory conditions, and we identify research gaps which should be covered in the future.

Nerve Growth Factor: A Potential Therapeutic Target for Lung Diseases

The lungs play a very important role in the human respiratory system. However, many factors can destroy the structure of the lung, causing several lung diseases and, often, serious damage to people's health. Nerve growth factor (NGF) is a polypeptide which is widely expressed in lung tissues. Under different microenvironments, NGF participates in the occurrence and development of lung diseases by changing protein expression levels and mediating cell function. In this review, we summarize the functions of NGF as well as some potential underlying mechanisms in pulmonary fibrosis (PF), coronavirus disease 2019 (COVID-19), pulmonary hypertension (PH), asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. Furthermore, we highlight that anti-NGF may be used in future therapeutic strategies.

Functional human iPSC-derived alveolar-like cells cultured in a miniaturized 96‑Transwell air-liquid interface model

In order to circumvent the limited access and donor variability of human primary alveolar cells, directed differentiation of human pluripotent stem cells (hiPSCs) into alveolar-like cells, provides a promising tool for respiratory disease modeling and drug discovery assays. In this work, a unique, miniaturized 96-Transwell microplate system is described where hiPSC-derived alveolar-like cells were cultured at an air-liquid interface (ALI). To this end, hiPSCs were differentiated into lung epithelial progenitor cells (LPCs) and subsequently matured into a functional alveolar type 2 (AT2)-like epithelium with monolayer-like morphology. AT2-like cells cultured at the physiological ALI conditions displayed characteristics of AT2 cells with classical alveolar surfactant protein expressions and lamellar-body like structures. The integrity of the epithelial barriers between the AT2-like cells was confirmed by applying a custom-made device for 96-parallelized transepithelial electric resistance (TEER) measurements. In order to generate an IPF disease-like phenotype in vitro, the functional AT2-like cells were stimulated with cytokines and growth factors present in the alveolar tissue of IPF patients. The cytokines stimulated the secretion of pro-fibrotic biomarker proteins both on the mRNA (messenger ribonucleic acid) and protein level. Thus, the hiPSC-derived and cellular model system enables the recapitulation of certain IPF hallmarks, while paving the route towards a miniaturized medium throughput approach of pharmaceutical drug discovery.

iTRAQ-Based Proteomics Reveals Gu-Ben-Fang-Xiao Decoction Alleviates Airway Remodeling via Reducing Extracellular Matrix Deposition in a Murine Model of Chronic Remission Asthma

Airway remodeling is a primary pathological feature of asthma. The current therapy for asthma mainly targets reducing inflammation but not particularly airway remodeling. Therefore, it is worthwhile to develop alternative and more effective therapies to attenuate remodeling. Gu-Ben-Fang-Xiao Decoction (GBFXD) has been used to effectively and safely treat asthma for decades. In this study, GBFXD regulated airway inflammation, collagen deposition, and the molecules relevant to airway remodeling such as Vimentin, α-SMA, hydroxyproline, and E-cadherin in chronic remission asthma (CRA) murine model. Proteomic analysis indicated that the overlapping differentially expressed proteins (DEPs) (Model/Control and GBFXD/Model) were mainly collagens and laminins, which were extracellular matrix (ECM) proteins. In addition, the KEGG analysis showed that GBFXD could regulate pathways related to airway remodeling including ECM-receptor interactions, focal adhesion, and the PI3K/AKT signaling pathway, which were the top three significantly enriched pathways containing the most DEPs for both Model/Control and GBFXD/Model. Further validation research showed that GBFXD regulated reticulon-4 (RTN4) and suppressed the activation of the PI3K/AKT pathway to alleviate ECM proteins deposition. In conclusion, our findings indicate that GBFXD possibly regulate the PI3K/AKT pathway via RTN4 to improve airway remodeling, which provides a new insight into the molecular mechanism of GBFXD for the treatment of CRA.

Ginsenoside Rh1 attenuates ovalbumin-induced asthma by regulating Th1/Th2 cytokines balance

Ginsenoside Rh1 (Rh1) has anti-inflammatory effects in asthma mice, but the underlying mechanism remains unclear. BALB/c mice were sensitized and challenged with ovalbumin (OVA) to construct asthma model. Mice received Rh1 or tiotropium bromide 0.5 h before OVA challenge. Airway morphology and airway remodeling were assessed by HE staining and Masson's trichrome staining, respectively. Th1/Th2 cytokines in serum or broncho alveolar lavage fluid (BALF) were measured by ELISA kits. Rh1 significantly alleviated the lung resistance and airway resistance, and reduced the number of total inflammation cells, eosinophils, neutrophils, and lymphocytes in BALF of the asthmatic mice. The morphological changes and collagen deposition of airway were also reduced by Rh1 in asthmatic mice. The increase of Eotaxin, IL-4, IL-5, IL-13, and IL-33 and the decrease of IL-12 and IFN-γ in both BALF and serum of OVA exposed mice were reversed by Rh1. Rh1 attenuates OVA-induced asthma in the mice model by regulating Th1/Th2 cytokines balance.

MicroRNA-21 inhibition attenuates airway inflammation and remodelling by modulating the transforming growth factor β-Smad7 pathway

BACKGROUND/AIMS

Current asthma therapies remain unsatisfactory for controlling airway remodelling in asthma. MicroRNA-21 is a key player in asthma pathogenesis, but the molecular mechanisms underlying its effects on airway remodelling are not completely understood. We investigated the effects of inhibition of microRNA-21 on allergic airway inflammation and remodelling.

METHODS

Female BALB/c mice were divided into four groups: control, ovalbumin-sensitized and -challenged for 3 months, microRNA-negative control-treated ovalbumin-treated, and microRNA-21 inhibitor-treated ovalbumin-treated groups. Parameters related to airway remodelling, cytokine production, airway inflammation, and airway hyperresponsiveness were compared between groups. Human bronchial smooth muscle cells were used in a mechanism study.

RESULTS

In this asthma model, ovalbumin-sensitized and -challenged mice exhibited allergic airway inf lammation and airway remodelling. MicroRNA-21 inhibitor-treated mice had fewer inflammatory cells, lower TH2 cytokine production, and suppressed parameters related to remodelling such as goblet cell hyperplasia, collagen deposition, hydroxyproline content, and expression of smooth muscle actin. Inhibition of microRNA-21 decreased transforming growth factor β1 expression and induced Smad7 expression in lung tissue. In human bronchial smooth muscle cells stimulated with transforming growth factor β1, microRNA-21 inhibition upregulated Smad7 expression and decreased markers of airway remodelling.

CONCLUSION

Inhibition of microRNA-21 had both anti-inflammatory and anti-remodelling effects in this model of ovalbumin-induced chronic asthma. Our data suggest that the microRNA-21-transforming growth factor β1-Smad7 axis modulates the pathogenesis of ovalbumin-induced chronic asthma and in human bronchial smooth muscle cells. MicroRNA-21 inhibitors may be a novel therapeutic target in patients with allergic asthma, especially those with airway remodelling.

Glycyrrhizic acid restrains airway inflammation and remodeling in asthma via the TGF-β1/Smad signaling pathway

The anti-inflammatory effects of glycyrrhizic acid (GA) against asthma have previously been reported; however, the underlying molecular mechanism of GA in asthma has not yet been elucidated. Thus, the present study aimed to determine the function and potential molecular mechanism of GA for modulating the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway in asthma-associated airway inflammation and remodeling. In order to study the mechanism of GA on airway inflammation and airway remodeling in asthmatic mice, a mouse model of chronic asthma was constructed. A total of 50 female mice were randomly assigned into five groups (10 mice/group), as follows: Blank group, asthma group, GA group, dexamethasone group and GA + TGF-β1 group. Hematoxylin and eosin, and Masson staining were performed to assess the airway inflammation and remodeling in mice with ovalbumin (OVA)-induced asthma. The serum levels of interleukin (IL)-4, IL-5, IL-13 and IL-17 in mice were assessed via the enzyme-linked immunosorbent assay. Reverse transcription-quantitative PCR and western blot analyses were performed to detect the levels of TGF-β1 and Smads in lung tissues of each group of mice. The results demonstrated that GA and dexamethasone treatment mitigated airway inflammation, inflammatory cell infiltration and airway remolding, with a concomitant decrease in the expression levels of IL-4, IL-5, IL-13 and IL-17, in mice with OVA-induced asthma. In addition, the levels of TGF-β1 and Smad2 notably decreased, while Smad7 expression increased in the GA and dexamethasone groups compared with the asthma group. Furthermore, histopathological morphometry exhibited significantly elevated inflammatory cell infiltration, airway wall and smooth muscle, collagen secretion and inflammatory cytokines in the serum of mice in the GA + TGF-β1 group compared with the GA group. Taken together, the results of the present study suggest that GA ameliorates airway inflammation and remodeling via the TGF-β1/Smad signaling pathway in mice with asthma.

Therapeutic potential of plant-derived tannins in non-malignant respiratory diseases

Respiratory diseases are the major cause of human illness and death around the world. Despite advances in detection and treatment, very few classes of safe and effective therapy have been introduced to date. At present, phytochemicals are getting more attention because of their diverse beneficial activities and minimal toxicity. Tannins are polyphenolic secondary metabolites with high molecular weights, which are naturally present in a wide variety of fruits, vegetables, cereals, and leguminous seeds. Many tannins are endowed with well-recognized protective properties, such as anti-cancer, anti-microbial, anti-oxidant, anti-hyperglycemic, and many others. This review summarizes a large body of experimental evidence implicating that tannins are helpful in tackling a wide range of non-malignant respiratory diseases including acute lung injury (ALI), pulmonary fibrosis, asthma, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). Mechanistic pathways by which various classes of tannins execute their beneficial effects are discussed. In addition, clinical trials and our perspective on future research with tannins are also reviewed.

NOX4-Derived ROS Promotes Collagen I Deposition in Bronchial Smooth Muscle Cells by Activating Noncanonical p38MAPK/Akt-Mediated TGF-β Signaling

Background

Airway smooth muscle (ASM) remodeling is a hallmark in chronic obstructive pulmonary disease (COPD). NADPH oxidase 4- (NOX4-) mediated reactive oxygen species (ROS) production plays a crucial role in cell differentiation and extracellular matrix (ECM) synthesis in ASM remodeling. However, the precise mechanisms underpinning its pathogenic roles remain elusive.

Methods

The expression of NOX4 and TGF-β₁ in the airway of the lung was measured in COPD patients and the control group. Cigarette smoke- (CS-) induced emphysema mice were generated, and the alteration of α-SMA, NOX4, TGF-β₁, and collagen I was accessed. The changes of the expression of ECM markers, NOX4, components of TGF-β/Smad, and MAPK/Akt signaling in human bronchial smooth muscle cells (HBSMCs) were ascertained for delineating mechanisms of NOX4-mediated ROS production on cell differentiation and remodeling in human ASM cells.

Results

An increased abundance of NOX4 and TGF-β₁ proteins in the epithelial cells and ASM of lung was observed in COPD patients compared with the control group. Additionally, an increased abundance expression of NOX4 and α-SMA was observed in the lungs of the CS-induced emphysema mouse model. TGF-β₁ displayed abilities to increase the oxidative burden and collagen I production, along with enhanced phosphorylation of ERK, p38MAPK, and p-Akt473 in HBSMCs. These effects of TGF-β₁ could be inhibited by the ROS scavenger N-acetylcysteine (NAC), siRNA-mediated knockdown of Smad3 and NOX4, and pharmacological inhibitors SB203580 (p38MAPK inhibitor) and LY294002 (Akt inhibitor).

Conclusions

NOX4-mediated ROS production alters TGF-β₁-induced cell differentiation and collagen I protein synthesis in HBSMCs in part through the p38MAPK/Akt signaling pathway in a Smad-dependent manner.

Acrylamide Induces Mitophagy and Alters Macrophage Phenotype via Reactive Oxygen Species Generation

Acrylamide is a readily exposed toxic organic compound due to its formation in many carbohydrate rich foods that are cooked at high temperatures. Excessive production of reactive oxygen species (ROS), which is an important factor for mitophagy, has been reported to lead to airway inflammation, hyper-responsiveness, and remodeling. Epigenetic regulation is an important modification affecting gene transcription. In this study, the effects of acrylamide on ROS productions and mitophagy were investigated. The human monocytic cell line THP-1 was treated with acrylamide, and ROS productions were investigated by flow cytometry. The mitochondrial and epigenetic involvement was evaluated by quantitative real-time PCR. Histone modifications were examined by chromatin immunoprecipitation assays. Mitophagy was detected by Western blotting and confocal laser microscopy. Acrylamide promoted mitochondria-specific ROS generation in macrophages. The gene expression of mitochondrial respiratory chain complex II SDHA was increased under acrylamide treatment. Acrylamide induced histone H3K4 and H3K36 tri-methylation in an SDHA promoter and increased mitophagy-related PINK1 expression, which promoted a M2-like phenotypic switch with increase TGF-β and CCL2 levels in THP-1 cells. In conclusion, acrylamide induced ROS production through histone tri-methylation in an SDHA promoter and further increased the expression of mitophagy-related PINK-1, which was associated with a macrophage M2 polarization shift.

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.

Riparin II potentials the effect of ephedrine on inflammation and remodelling in the airway of rats suffering from asthma by regulating transforming growth factor-β/Smad3 signalling pathway

Asthma is a chronic obstructive lung disorder involving hyperresponsive lung tissue. This study evaluated the protective effects of riparin II against asthma and determined the synergistic effects of riparin II with ephedrine in treatment of asthma. Asthma was induced by intraperitoneal injection of Al(OH)3 (100 mg) with ovalbumin 1 mg/kg and subsequent exposure to 2% ovalbumin aerosol for 1 week. All animals were treated with riparin II 50 mg/kg and ephedrine 25 mg/kg alone and in combination for the duration of the study. Interleukin levels were assessed in the serum and bronchoalveolar lavage fluid (BALF) of asthmatic rats, while inflammatory cell infiltration was determined in the lungs. Airway remodelling was determined by assessing the lung tissue expression levels of transforming growth factor beta 1 (TGF-β1), Smad, and collagen I in asthmatic rats. There were lower levels of cytokines in the serum and BALF in riparin II-treated rats than in negative control rats. Moreover, inflammatory cell and IgE levels were reduced while interferon level was enhanced in the lungs of riparin II-treated rats, compared to negative control rats. These data reveal that treatment with riparin II ameliorates the altered expression of TGF-β1, Smad, and collagen I in lung tissue of asthmatic rats. In conclusion, riparin II treatment alone and in combination with ephedrine ameliorated the hyperresponsiveness of lung tissue due to reductions in airway remodelling and inflammation in asthmatic rats.

Effects of Inhalation of STIM-Orai Antagonist SKF 96365 on Ovalbumin-Induced Airway Remodeling in Guinea Pigs

Airway remodeling (AR) consists of wall thickening and hyperreactivity. STIM (stromal interaction molecule) and Orai protein pathways mediate extracellular Ca²⁺ signals involved in AR. This study aims to define the effects on AR of the STIM-Orai antagonist SKF 96365 given by inhalation in three increasing doses in ovalbumin-induced AR. In the control group, the antiasthmatic budesonide and salbutamol were given in the same model. The airway structure was evaluated by histological and immunohistochemistry and reactivity by specific airway resistance, contraction strength of isolated airway smooth muscles, and mucociliary clearance expressed by ciliary beating frequency. The immuno-biochemical markers of chronic inflammation were evaluated by BioPlex and ELISA assays. The AR was mediated by inflammatory cytokines and growth factors. The findings show significant anti-remodeling effects of SKF 96365, which were associated with a decrease in airway hyperreactivity. The anti-remodeling effect of SKF 96365 was mediated via the suppression of IL-4, IL-5, and IL-13 synthesis, and IL-12-INF-γ-TGF-β pathway. The budesonide-related AR suppression had to do with a decrease in proinflammatory cytokines and an increase in the anti-inflammatory IL-10, with negligible influence on growth factors synthesis and mucous glands activity.

Effect of anti-IL17 and/or Rho-kinase inhibitor treatments on vascular remodeling induced by chronic allergic pulmonary inflammation

Background and aims:

Expansion and morphological dysregulation of the bronchial vascular network occurs in asthmatic airways. Interleukin (IL) -17 and Rho-kinase (ROCK) are known to act in inflammation control and remodeling. Modulation of Rho-kinase proteins and IL-17 may be a promising approach for the treatment of asthma through the control of angiogenesis. Our objective was to analyze the effects of treatment with anti-IL17 and/or Rho-kinase inhibitor on vascular changes in mice with chronic allergic pulmonary inflammation.

Methods:

Sixty-four BALB/c mice, with pulmonary inflammation induced by ovalbumin were treated with anti-IL17A (7.5/µg per dose, intraperitoneal) and/or Rho-kinase inhibitor (Y-27632-10 mg/kg, intranasal), 1 h before each ovalbumin challenge (22, 24, 26, and 28/days). Control animals were made to inhale saline. At the end of the protocol, lungs were removed, and morphometric analysis was performed to quantify vascular inflammatory, remodeling, and oxidative stress responses.

Results:

Anti-IL17 or Rho-kinase inhibitor reduced the number of CD4⁺, CD8⁺, dendritic cells, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, Rho-kinase 1 and 2, transforming growth factor (TGF-β), vascular endothelial growth factor (VEGF), nuclear factor (NF)-KappaB, iNOS, metalloproteinase (MMP)-9, MMP-12, metalloproteinase inhibitor-1 (TIMP-1), FOXP-3, signal transducer and activator of transcription 1 (STAT1) and phospho-STAT1-positive cells, and actin, endothelin-1, isoprostane, biglycan, decorin, fibronectin and the collagen fibers volume fraction compared with the ovalbumin group (p < 0.05). The combination treatment, when compared with anti-IL17, resulted in potentiation of decrease in the number of IL1β- and dendritic cells-positive cells. When we compared the OVA-RHO inhibitor-anti-IL17 with OVA-RHO inhibitor we found a reduction in the number of CD8⁺ and IL-17, TGF-β, and phospho-STAT1-positive cells and endothelin-1 in the vessels (p < 0.05). There was an attenuation in the number of ROCK 2-positive cells in the group with the combined treatment when compared with anti-IL17 or Rho-kinase inhibitor-treated groups (p < 0.05).

Conclusion:

We observed no difference in angiogenesis after treatment with Rho-kinase inhibitor and anti-IL17. Although the treatments did not show differences in angiogenesis, they showed differences in the markers involved in the angiogenesis process contributing to inflammation control and vascular remodeling.

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

Epithelial-to-mesenchymal transition in neutrophilic chronic rhinosinusitis

PURPOSE OF REVIEW

Barrier dysfunction, tissue fibrosis, and remodeling are essential processes of the pathophysiology of chronic rhinosinusitis (CRS). The role of epithelial-to-mesenchymal transition (EMT) has been assessed in various studies in CRS. In this review, we summarized the pathophysiologic mechanisms of EMT related to CRS, particularly neutrophilic CRS.

RECENT FINDINGS

Loss of epithelial characteristics due to EMT makes leaky epithelium, and transformed mesenchymal cells cause fibrosis and remodeling. Hypoxia, allergens (house dust mites), infections, and air pollutants were related to the pathogenesis of neutrophilic CRS, and these factors are known to induce barrier dysfunction and EMT in sinonasal epithelia. Some molecular pathways related to EMT have been recognized in CRS, including interferon-γ/p38/extracellular signal-regulated kinase, high-mobility group box 1/receptor of advanced glycosylation end-products, TGF-β1/SMAD, and Wnt/β-catenin-signaling pathways. Apart from, several microRNAs (miR-21, miR-761, and miR-30a-5p) have been identified to regulate EMT in CRS.

SUMMARY

EMT is considered to be an important pathogenesis mechanism for CRS. The factors cause EMT in CRS, and the associated molecular mechanisms are related to neutrophilic inflammation. Further studies on CRS endotype and/or phenotype are needed to clarify the implication of EMT on CRS pathogenesis.

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).

Recombinant Pyrin Domain Protein Attenuates Airway Inflammation and Alleviates Epithelial-Mesenchymal Transition by Inhibiting Crosstalk Between TGFβ1 and Notch1 Signaling in Chronic Asthmatic Mice

This article aims to investigate the effects of recombinant pyrin domain (RPYD) on airway inflammation and remodeling in mice with chronic asthma. The chronic asthma BALB/c mouse model was first sensitized by ovalbumin (OVA) and then challenged by OVA nebulization. RPYD or dexamethasone was given before OVA challenge. Our results showed that RPYD significantly inhibited the increase of total cell number, eosinophils, neutrophils and lymphocytes in bronchoalveolar lavage fluid (BALF) induced by OVA, and reduced the infiltration of inflammatory cells, the proliferation of goblet cells and collagen deposition. In addition, RPYD inhibited the mRNA and protein levels of α-smooth muscle actin (α-SMA), transforming growth factor (TGF)-β1, Jagged1, Notch1, Hes1 and Smad3, as well as Smad3 phosphorylation. TGFβ1 down-regulated the level of E-cadherin and promoted the expression of α-SMA, thus inducing epithelial-mesenchymal transition (EMT) in bronchial epithelial cells. We found that RPYD reduced EMT by inhibiting TGFβ1/smad3 and Jagged1/Notch1 signaling pathways. Further overexpression of NICD showed that under the stimulation of TGFβ1, NICD enhanced the phosphorylated Smad3 and nuclear Smad3, accompanied by the increased expression of Notch1 target gene Hes1. In contrast, after treatment with smad3 siRNA, the expression of Hes1 was down regulated as the decrease of Smad3, which indicates that there is crosstalk between smad3 and NICD on Hes1 expression. In conclusion, RPYD reduces airway inflammation, improves airway remodeling and reduces EMT in chronic asthmatic mice by inhibiting the crosstalk between TGFβ1/smad3 and Jagged1/Notch1 signaling pathways.

Effects of Wnt signaling on epithelial to mesenchymal transition in chronic rhinosinusitis with nasal polyp

Background

Epithelial to mesenchymal transition (EMT) is associated with the pathophysiology of chronic rhinosinusitis with nasal polyp (CRSwNP). Wnt signaling is causative for EMT, whereas the mechanism in CRSwNP is not fully understood.

Objective

We sought to evaluate the role of Wnt signaling in EMT of CRSwNP using a murine nasal polyp (NP) model and human tissues.

Methods

Inflammatory markers and EMT-related molecules were evaluated in NP models using adenomatosis polyposis coli (Apc)Min/+ mice with activated Wnt signaling and NP models treated with Wnt signaling inhibitor, indocyanine green-001 (ICG-001). EMT markers and Wnt signaling-associated mediators were analysed using human sinonasal tissues from control subjects and CRSwNP patients.

Results

ApcMin/+ mice-induced NPs exhibited more frequent polypoid lesions and upregulation of Wnt-related molecules, including nuclear β-catenin, WNT3A and cyclin D1. Markers of EMT were significantly overexpressed in the ApcMin/+ NP mice (p<0.001 for E-cadherin and α-smooth muscle actin), and interleukin (IL)-17A+ cells and neutrophilic infiltration were increased in ApcMin/+ NP mice (p<0.001). Inhibition of Wnt signaling via ICG-001 resulted in significantly decreased nasal polypoid lesions (p<0.001), EMT-related markers (p=0.019 for E-cadherin and p=0.002 for vimentin) and the mRNA levels of IL-4 (p<0.001) and IL-17A (p=0.004) compared with the positive control group. Finally, nuclear β-catenin (p=0.042) was significantly increased compared with the control, and the expression levels of Wnt ligands and receptors were upregulated in human NP tissues (p=0.045 for WNT3A and p=0.042 for FZD2), suggesting increased Wnt signaling and EMT in CRSwNP.

Conclusion

Wnt signaling may contribute to the pathogenesis of NPs through EMT. Therefore, inhibition of Wnt signaling may be a potential therapeutic strategy for patients with CRSwNP.

Airway mechanical compression: its role in asthma pathogenesis and progression

The lung is a mechanically active organ, but uncontrolled or excessive mechanical forces disrupt normal lung function and can contribute to the development of disease. In asthma, bronchoconstriction leads to airway narrowing and airway wall buckling. A growing body of evidence suggests that pathological mechanical forces induced by airway buckling alone can perpetuate disease processes in asthma. Here, we review the data obtained from a variety of experimental models, including in vitro, ex vivo and in vivo approaches, which have been used to study the impact of mechanical forces in asthma pathogenesis. We review the evidence showing that mechanical compression alters the biological and biophysical properties of the airway epithelium, including activation of the epidermal growth factor receptor pathway, overproduction of asthma-associated mediators, goblet cell hyperplasia, and a phase transition of epithelium from a static jammed phase to a mobile unjammed phase. We also define questions regarding the impact of mechanical forces on the pathology of asthma, with a focus on known triggers of asthma exacerbations such as viral infection.