Wogonoside Ameliorates Airway Inflammation and Mucus Hypersecretion via NF-κB/STAT6 Signaling in Ovalbumin-Induced Murine Acute Asthma

Asthma is recognized as a chronic respiratory illness characterized by airway inflammation and airway hyperresponsiveness. Wogonoside, a flavonoid glycoside, is reported to significantly alleviate the inflammation response and oxidative stress. Herein, this study aimed to investigate the therapeutic effect and underlying mechanism of wogonoside on airway inflammation and mucus hypersecretion in a murine asthma model and in human bronchial epithelial cells (16HBE). BALB/c mice were sensitized and challenged with ovalbumin (OVA). Pulmonary function and the number of cells in the bronchoalveolar lavage fluid (BALF) were examined. Pathological changes in lung tissue in each group were evaluated via hematoxylin and eosin and periodic acid-Schiff staining, and changes in levels of cytokines in BALF and of immunoglobulin E in serum were determined via an enzyme-linked immunosorbent assay. The expression of relevant genes in lung tissue was analyzed via real-time PCR. Western blotting and immunofluorescence were employed to detect the expression of relevant proteins in lung tissue and 16HBE cells. Treatment with 10 and 20 mg/kg wogonoside significantly attenuated the OVA-induced increase of inflammatory cell infiltration, mucus secretion, and goblet cell percentage and improved pulmonary function. Wogonoside treatment reduced the level of T-helper 2 cytokines including interleukin (IL)-4, IL-5, and IL-13 in BALF and of IgE in serum and decreased the mRNA levels of cytokines (IL-4, IL-5, IL-6, IL-13, and IL-1β and tumor necrosis factor-α), chemokines (CCL-2, CCL-11, and CCL-24), and mucoproteins (MUC5AC, MUC5B, and GOB5) in lung tissues. The expression of MUC5AC and the phosphorylation of STAT6 and NF-κB p65 in lung tissues and 16HBE cells were significantly downregulated after wogonoside treatment. Thus, wogonoside treatment may effectively decrease airway inflammation, airway remodeling, and mucus hypersecretion via blocking NF-κB/STAT6 activation.

Lactiplantibacillusplantarum APsulloc331261 (GTB1™) promotes butyrate production to suppress mucin hypersecretion in a murine allergic airway inflammation model

Introduction

Allergic airway diseases are one of the serious health problems in worldwide and allergic airway inflammation is a prerequisite led to the exacerbated situation such as mucus hypersecretion, epithelial barrier damage and microbiota dysbiosis. Because of side effects and low efficiencies of current therapeutics, the need for novel alternatives has been urged. Probiotics in which have diverse and beneficial modulatory effects have been applied to the airway inflammation model and the underlying mechanism needs to be investigated.

Methods

We aimed to evaluate whether our target strain, Lactiplantibacillus plantarum APsulloc331261 (GTB1TM) isolated from green tea, can ameliorate allergic airway inflammation in mice and to figure out the mechanism. We induced allergic airway inflammation to mice by ovalbumin (OVA) and administered GTB1 orally and the immune and epithelial barrier markers were assessed. The gut metabolite and microbiota were also analysed, and the in vitro cell-line experiment was introduced to confirm the hypothesis of the study.

Results

GTB1 ameliorated type 2 inflammation and suppressed mucin hypersecretion with the inhibition of MUC5AC in inflamed mice. Moreover, GTB1 increased the butyrate production and the relative abundance of butyrate producer, Clostridium cluster IV. We assumed that butyrate may have a potential role and investigated the effect of butyrate in mucin regulation via human airway epithelial cell line, A549. Butyrate significantly reduced the gene expression of MUC5AC in A549 cells suggesting its regulatory role in mucus production.

Conclusion

Therefore, our study demonstrates that the oral administration of GTB1 can ameliorate allergic airway inflammation and mucin hypersecretion by butyrate production.

Stigmasterol alleviates allergic airway inflammation and airway hyperresponsiveness in asthma mice through inhibiting substance-P receptor

CONTEXT

Stigmasterol has significant anti-arthritis and anti-inflammatory effects, but its role in immune and inflammatory diseases is still unclear.

OBJECTIVE

The potential advantages of stigmasterol in asthma were explored in IL-13-induced BEAS-2B cells and asthmatic mice.

MATERIALS AND METHODS

The optimal target of stigmasterol was confirmed in asthma. After detecting the cytotoxicity of stigmasterol in BEAS-2B cells, 10 μg/mL and 20 μg/mL stigmasterol were incubated with the BEAS-2B cell model for 48 h, and anti-inflammation and antioxidative stress were verified. Asthmatic mice were induced by OVA and received 100 mg/kg stigmasterol for 7 consecutive days. After 28 days, lung tissues and BAL fluid were collected for the following study. To further verify the role of NK1-R, 0.1 μM WIN62577 (NK1-R specific antagonist), and 1 μM recombinant human NK1-R protein were applied.

RESULTS

NK1-R was the potential target of stigmasterol. When the concentration of stigmasterol is 20 μg/mL, the survival rate of BEAS-2B cells is about 98.4%, which is non-toxic. Stigmasterol exerted anti-inflammation and antioxidant stress in a dose-dependent manner and decreased NK1-R expression in IL-13-induced BEAS-2B. Meanwhile, in vivo assay also indicated the anti-inflammation and antioxidant stress of stigmasterol after OVA challenge. Stigmasterol inhibited inflammation infiltration and mucus hypersecretion, and NK1-R expression.

DISCUSSION AND CONCLUSIONS

The protective effect of stigmaterol on asthma and its underlying mechanism have been discussed in depth, providing a theoretical basis and more possibilities for its treatment of asthma.

Camellia sinensis (L.) Kuntze Extract Attenuates Ovalbumin-Induced Allergic Asthma by Regulating Airway Inflammation and Mucus Hypersecretion

Asthma is a pulmonary disease induced by the inhalation of aeroallergens and subsequent inappropriate immune responses. Camellia sinensis (L.) Kuntze has been evaluated as an effective antioxidant supplement produced from bioactive compounds, including flavonoids. In this study, we aimed to determine the effects of Camellia sinensis (L.) Kuntze extract (CE) on ovalbumin-induced allergic asthma. The components of CE were analyzed using high-performance liquid chromatography (HPLC) chromatogram patterns, and asthmatic animal models were induced via ovalbumin treatment. The antioxidant and anti-inflammatory effects of CE were evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), and nitric oxide (NO) assays. Seven compounds were detected in the CE chromatogram. In the ovalbumin-induced mouse model, CE treatment significantly decreased the inflammation index in the lung tissue. CE also significantly decreased eosinophilia and the production of inflammatory cytokines and OVA-specific IgE in animals with asthma. Collectively, our results indicate that CE has anti-inflammatory and antioxidant activities, and that CE treatment suppresses asthmatic progression, including mucin accumulation, inflammation, and OVA-specific IgE production.

Inhibition of TRPA1, Endoplasmic Reticulum Stress, Human Airway Epithelial Cell Damage, and Ectopic MUC5AC Expression by Vasaka (Adhatoda vasica; Malabar Nut) Tea

This study tested whether a medicinal plant, Vasaka, typically consumed as a tea to treat respiratory malaise, could protect airway epithelial cells (AECs) from wood smoke particle-induced damage and prevent pathological mucus production. Wood/biomass smoke is a pneumotoxic air pollutant. Mucus normally protects the airways, but excessive production can obstruct airflow and cause respiratory distress. Vasaka tea pre- and co-treatment dose-dependently inhibited mucin 5AC (MUC5AC) mRNA induction by AECs treated with wood smoke particles. This correlated with transient receptor potential ankyrin-1 (TRPA1) inhibition, an attenuation of endoplasmic reticulum (ER) stress, and AEC damage/death. Induction of mRNA for anterior gradient 2, an ER chaperone/disulfide isomerase required for MUC5AC production, and TRP vanilloid-3, a gene that suppresses ER stress and wood smoke particle-induced cell death, was also attenuated. Variable inhibition of TRPA1, ER stress, and MUC5AC mRNA induction was observed using selected chemicals identified in Vasaka tea including vasicine, vasicinone, apigenin, vitexin, isovitexin, isoorientin, 9-oxoODE, and 9,10-EpOME. Apigenin and 9,10-EpOME were the most cytoprotective and mucosuppressive. Cytochrome P450 1A1 (CYP1A1) mRNA was also induced by Vasaka tea and wood smoke particles. Inhibition of CYP1A1 enhanced ER stress and MUC5AC mRNA expression, suggesting a possible role in producing protective oxylipins in stressed cells. The results provide mechanistic insights and support for the purported benefits of Vasaka tea in treating lung inflammatory conditions, raising the possibility of further development as a preventative and/or restorative therapy.

[Yifei Jianpi recipe improves cigarette smoke-induced inflammatory injury and mucus hypersecretion in human bronchial epithelial cells by inhibiting the TLR4/NF-κB signaling pathway]

OBJECTIVE

To explore the mechanism of Yifei Jianpi recipe for improving cigarette smoke- induced inflammatory injury and mucus hypersecretion in cultured human bronchial epithelial cells.

METHODS

Serum samples were collected from 40 SD rats treated with Yifei Jianpi recipe (n=20) or normal saline (n=20) by gavage. Cultured human bronchial epithelial 16HBE cells were stimulated with an aqueous cigarette smoke extract (CSE), followed by treatment with the collected serum at different dilutions. The optimal concentration and treatment time of CSE and the medicated serum for cell treatment were determined with CCK-8 assay. The expressions of TLR4, NF-κB, MUC5AC, MUC7, and muc8 at both the mRNA and protein levels in the treated cells were examined with RT- qPCR and Western blotting, and the effects of TLR4 gene silencing and overexpression on their expressions were assessed. The expressions of TNF-α, IL-1 β, IL-6 and IL-8 in the cells were detected using ELISA.

RESULTS

At the optimal concentration of 20%, treatment with the medicated serum for 24 h significantly lowered the mRNA and protein expressions of TLR4, NF- κB, MUC5AC, MUC7, and MUC8 in CSE- exposed 16HBE cells, and these effects were further enhanced by TLR4 silencing in the cells. In 16HBE cells with TLR4 overexpression, the expressions of TLR4, NF-κB, MUC5AC, MUC7, and MUC8 were significantly increased after CSE exposure and were lowered following treatment with the medicated serum (P < 0.05). The medicated serum also significantly lowered the levels of TNF-α, IL-1β, IL-6 and IL-8 in CSE-exposed 16HBE cells (P < 0.05).

CONCLUSIONS

In the 16HBE cell model of chronic obstructive pulmonary disease (COPD), treatment with Yifei Jianpi recipe-medicated serum improves inflammation and mucus hypersecretion possibly by reducing MUC secretion and inhibiting the TLR4/NF-κB signaling pathway.

Bronchoscopic Management of COPD and Advances in Therapy

Chronic Obstructive Pulmonary Disease (COPD) is a highly prevalent and morbid disease marked by irreversible structural changes in the lungs. Bronchoscopic therapies have significantly expanded the treatment armamentarium for patients with persistent symptoms by reducing the physiologic detriments of hyperinflation in a less invasive fashion than surgical lung volume reduction. The spectrum of bronchoscopic techniques to reduce hyperinflation includes endobronchial valves, coils, thermal ablation, and biologic sealants. Other therapies focus on reducing parasympathetic tone and mucus hypersecretion and include targeted lung denervation, bronchial rheoplasty, and cryospray techniques. In this article, we will review the variety of techniques for bronchoscopic lung volume reduction, both established and investigational, along with their respective benefits and complications and will briefly review other investigational therapies for COPD.

[Effects of Butylphthalide on airway mucus hypersecretion, IL-13 and TNF-α in asthmatic mice]

Objective: To investigate the effects of Butylphthalide (NBP) on airway mucus hypersecretion, interleukin-13 (IL-13) and tumor necrosis factor-α (TNF-α) in asthmatic mice. Methods: The mice were randomly divided into control group, asthma group, DEX group and high, medium and low doses of NBP (100, 50, 25 mg/kg) groups (n=12). Ovalbumin (OVA) injection was sensitized on the 1st, 8th, and 15th day of the experiment, and OVA was inhaled on the 22nd day to stimulate for 5 weeks to replicate the asthma model, and 20 mg/kg of NBP was given for intervention before the challenge. Finally, the asthma behavior, the secretion of goblet cells and Mucin 5ac (Muc5ac)were observed, and meanwhile the viscosity of bronchoalveolar lavage fluid (BALF) and the levels of Muc5ac, IL-13 and TNF-α in BALF were measured by ELISA. Results: Compared with the control group, the degree of sneezing, nose scratching and asthma, the proliferation of airway epithelial goblet cells and secretion of Muc5ac in the asthma group were increased significantly (P＜0.01), meanwhile, the viscosity of BALF and the contents of Muc5ac, IL-13 and TNF-α were also increased significantly (P＜0.01). Compared with the asthma group, the above behavioral scores of asthma were decreased significantly (P＜0.01) after the intervention of 25, 50 and 100 mg/kg NBP, as well as the proliferation of airway epithelial goblet cells, secretion of Muc5ac, the viscosity of BALF and the contents of Muc5ac, IL-13 and TNF-α were significantly lower than those of the asthma group (P＜0.05, 0.01). Conclusion: NBP has the effect of anti-asthma by inhibiting mucus hypersecretion, and one of its mechanisms is to alleviate the abnormal expressions of IL-13 and TNF-α.

Autophagy Modulators From Chinese Herbal Medicines: Mechanisms and Therapeutic Potentials for Asthma

Asthma has become a global health issue, suffering more than 300 million people in the world, which is a heterogeneous disease, usually characterized by chronic airway inflammation and airway hyperreactivity. Combination of inhaled corticosteroids (ICS) and long acting β-agonists (LABA) can relieve asthma symptoms and reduce the frequency of exacerbations, especially for patients with refractory asthma, but there are limited treatment options for people who do not gain control on combination ICS/LABA. The increase in ICS dose generally provides little additional benefit, and there is an increased risk of side effects. Therefore, therapeutic interventions integrating the use of different agents that focus on different targets are needed to overcome this set of diseases. Some findings suggest autophagy is closely correlated with the severity of asthma through eosinophilic inflammation, and its modulation may provide novel therapeutic approaches for severe allergic asthma. The chinese herbal medicine (CHM) have been demonstrated clinically as potent therapeutic interventions for asthma. Moreover some reports have found that the bioactive components isolated from CHM could modulate autophagy, and exhibit potent Anti-inflammatory activity. These findings have implied the potential for CHMs in asthma or allergic inflammation therapy via the modulation of autophagy. In this review, we discuss the basic pathomechanisms underpinning asthma, and the potential role of CHMs in treating asthma with modulating autophagy.

sRAGE Inhibits the Mucus Hypersecretion in a Mouse Model with Neutrophilic Asthma

Background: Neutrophilic asthma (NA) may result in irreversible airflow limitations. Soluble advanced glycosylation receptor (sRAGE) has been shown to be associated with neutrophilic airway inflammation. However, the association between sRAGE and mucus hypersecretion in NA remains unknown. This study aims to assess the function of sRAGE on mucus hypersecretion.Methods: A NA mouse model was established and treated with adeno-associated virus 9 (AAV9)-sRAGE and inhibitors. Collagen deposition and goblet cell hyperplasia in the lungs were evaluated by periodic acid-Schiff (PAS) and Masson staining. sRAGE and mucin levels in bronchoalveolar lavage fluid were measured by ELISA. Pathway molecule expression levels were determined by RT-qPCR and western blotting.Results: The results showed that the NA mouse model exhibited airway mucus hypersecretion. Mice can be effectively transfected by AAV9-sRAGE via tail-vein injection and intranasal drip. AAV9-sRAGE increased the sRAGE levels but it inhibited the collagen deposition, the PAS score, as well as the expression of MUC5AC and MUC5B. Inhibitors of high-mobility group protein 1 (HMGB1), receptor for advanced glycation end product (RAGE) and phosphatidylinositol 3-kinase (PI3K) suppressed the MUC5AC levels in NA mice as well as in cultured HMGB1-induced human bronchial epithelial cells. Furthermore, the phospho- extracellular signal-regulated kinase (ERK) protein in NA was increased while the sRAGE intervention inhibited this elevation.Conclusions: These results suggest that sRAGE may be a potential target for the treatment of mucus hypersecretion in NA.

Aesculetin Inhibits Airway Thickening and Mucus Overproduction Induced by Urban Particulate Matter through Blocking Inflammation and Oxidative Stress Involving TLR4 and EGFR

Particulate matter (PM) is a mixture of solid and liquid air pollutant particles suspended in the air, varying in composition, size, and physical features. PM is the most harmful form of air pollution due to its ability to penetrate deep into the lungs and blood streams, causing diverse respiratory diseases. Aesculetin, a coumarin derivative present in the Sancho tree and chicory, is known to have antioxidant and anti-inflammatory effects in the vascular and immune system. However, its effect on PM-induced airway thickening and mucus hypersecretion is poorly understood. The current study examined whether naturally-occurring aesculetin inhibited airway thickening and mucus hypersecretion caused by urban PM₁₀ (uPM₁₀, particles less than 10 μm). Mice were orally administrated with 10 mg/kg aesculetin and exposed to 6 μg/mL uPM₁₀ for 8 weeks. To further explore the mechanism(s) involved in inhibition of uPM₁₀-induced mucus hypersecretion by aesculetin, bronchial epithelial BEAS-2B cells were treated with 1–20 µM aesculetin in the presence of 2 μg/mL uPM₁₀. Oral administration of aesculetin attenuated collagen accumulation and mucus hypersecretion in the small airways inflamed by uPM₁₀. In addition, aesculetin inhibited uPM₁₀-evoked inflammation and oxidant production in lung tissues. Further, aesculetin accompanied the inhibition of induction of bronchial epithelial toll-like receptor 4 (TLR4) and epidermal growth factor receptor (EFGR) elevated by uPM₁₀. The inhibition of TLR4 and EGFR accompanied bronchial mucus hypersecretion in the presence of uPM₁₀. Oxidative stress was responsible for the epithelial induction of TLR4 and EGFR, which was disrupted by aesculetin. These results demonstrated that aesculetin ameliorated airway thickening and mucus hypersecretion by uPM₁₀ inhalation by inhibiting pulmonary inflammation via oxidative stress-stimulated TLR4 and EGFR. Therefore, aesculetin may be a promising agent for treating airway mucosa-associated disorders elicited by urban coarse particulates.

[Effects of Radix Angelicae Sinensis on airway mucus hypersecretion and the TNF-α/NF-κB signaling pathway in Yin-deficiency asthmatic mice]

Objective: To investigate the therapeutic effects of Radix Angelicae Sinensis (RADA) on airway mucus hypersecretion and the tumor necrosis factor-α/ nuclear factor- κB (TNF-α/NF-κB) signaling pathway in Yin-deficiency asthma mice. Methods: KM mice were randomly divided into control group, model group, ambroxol group and RADA low, medium and high dose (2, 4 and 8 g/kg) group(n=12). Ovalbumin and the thyroid gland were used to replicate the model of Yin-deficiency asthma. Asthma symptoms in mice , immune globulin E (IgE) , TNF-α , and the expressions of Mucin 5ac (Muc5ac) and NF- κB in lung tissue were observed under the intervention of RADA. Results: RADA at the doses of 2,4 and 8 g/kg could alleviate the asthma symptoms of Yin-deficiency asthma mice significantly, reduce the levels of IgE in serum and TNF-α in bronchoalveolar lavage fluid (BALF), and inhibite the overexpressions of Muc5ac and NF- κB in lung tissue. Conclusion: RADA has significant anti-asthmatic effect. One of its mechanisms is to inhibit TNF-α/NF- κB signaling pathway and to alleviate airway mucus hypersecretion.

Pic Protein From Enteroaggregative E. coli Induces Different Mechanisms for Its Dual Activity as a Mucus Secretagogue and a Mucinase

A hallmark of enteroaggregative Escherichia coli (EAEC) infection is the formation of an intestinal biofilm, which comprises a mucus layer with immersed bacteria. Pic is an autotransporter secreted by EAEC, and other E. coli pathotypes, and has been involved in two apparently contradictory phenotypes, as a mucus secretagogue and as a mucinase. Here, we investigated this Pic dual activity, mucus secretagogue capability and mucinolytic activity, in human goblet cells that secrete MUC2 and MUC5AC. Pic induced mucus hypersecretion directly in the goblet cells, without other intestinal cell types involved. At the same time, Pic exhibited strong proteolytic activity on the secreted mucins. These activities were independent since a mutation in the serine protease motif (PicS258I) abolished mucin degradation while maintaining the mucus secretagogue activity intact. Furthermore, deoxycholic acid (DCA)-induced mucins were proteolytically degraded when goblet cells were co-incubated with DCA/Pic, while co-incubation with DCA/PicS258I induced a synergistic effect on mucus hypersecretion. Pic was more efficient degrading MUC5AC than MUC2, but no degradation was detected with Pic inactivated at the active site by mutation or pharmacological inhibition. Remarkably, Pic cleaved MUC2 and MUC5AC in the C-terminal domain, leaving N-terminal subproducts, impacting the feature of gel-forming mucins and allowing mucus layer penetration by EAEC. Astonishingly, Pic stimulated rapid mucin secretion in goblet-like cells by activating the intracellular calcium pathway resulting from the PLC signal transduction pathway, leading to the production of DAG and releasing IP₃, a second messenger of calcium signaling. Therefore, the dual activity of Pic, as a mucus secretagogue and a mucinase, is relevant in the context of carbon source generation and mucus layer penetration, allowing EAEC to live within the layer of mucus but also access epithelial cells.

Massive atelectasis by mucoid impaction in an asthma patient during treatment with anti-interleukin-5 receptor antibody

Benralizumab is an interleukin-5 (IL-5) receptor α-directed cytolytic monoclonal antibody that reduces rapid and nearly complete depletion of eosinophils by enhancing antibody-dependent cell-mediated cytotoxicity. The depletion of eosinophilic inflammation is expected to reduce mucus hypersecretion and mucoid impaction. A 75-year-old non-smoking female had been treated for uncontrolled bronchial asthma with multiple drugs. Treatment with benralizumab was initiated after the asthma attack; however, four months later, she developed massive atelectasis in the left lung leading to the tracheal deviation, to the extent that nasal high-flow therapy was required. The laboratory data showed elevated neutrophil count, whereas blood eosinophils were almost completely depleted. The thick mucus was removed by bronchofiberscopy and the atelectasis was completely resolved. No exacerbation has been observed for nine months after discontinuation of benralizumab and initiation of erythromycin. This is the first documented case that developed atelectasis by mucoid impaction during treatment with anti-IL-5 receptor antibody.

A Functional Respiratory Imaging Approach to the Effect of an Oscillating Positive Expiratory Pressure Device in Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) patients are prone to suffer from chronic bronchitis, which ultimately affects their quality of life and overall prognosis. Oscillating positive expiratory pressure (oPEP) devices are designed to aid in the mucus clearance by generating positive pressure pulses in the airways. The main aim of this study was to analyze the impact of a specific oPEP device - Aerobika^® - on top of standard of care medication in COPD patients' lung dynamics and drug deposition.

Patients and Methods

In this single-arm pilot study, patients were assessed using standard spirometry tests and functional respiratory imaging (FRI) before and after a period of 15±3 days of using the oPEP device twice daily (before their standard medication).

Results

The utilization of the oPEP device led to a significant increase of 2.88% in specific airway volume after two weeks (1.44 (SE: 0.18) vs 1.48 (SE: 0.19); 95% CI = [0.03%,5.81%]; p=0.048). Moreover, the internal airflow distribution (IAD) was affected by the treatment: patients' changes ranged from -6.74% to 4.51%. Furthermore, IAD changes at the lower lobes were also directly correlated with variations in forced expiratory volume in one second and peak expiratory flow; conversely, IAD changes at the upper lobes were inversely correlated with these clinical parameters. Interestingly, this change in IAD was significantly correlated with changes in lobar drug deposition (r ²=0.30, p<0.001).

Conclusion

Our results support that the Aerobika device utilization leads to an improved airflow, which in turn causes a shift in IAD and impacts the drug deposition patterns of the concomitant medication in patients with COPD.

The Role of Fucoidans Isolated from the Sporophylls of Undaria pinnatifida against Particulate-Matter-Induced Allergic Airway Inflammation: Evidence of the Attenuation of Oxidative Stress and Inflammatory Responses

Ambient particulate matter (PM) is a critical environment pollutant that promotes the onset and aggravation of respiratory diseases such as asthma through airway inflammation and hypersecretion of mucus. In this study, we aimed to identify the effects of fucoidans isolated from sporophylls of Undaria pinnatifida on asthma symptoms such as the inflammatory response and mucus secretion using a mouse model. Balb/c mice, intraperitoneally sensitized with ovalbumin (OVA, 10 μg) dissolved in 200 µL saline and 2 mg Al(OH)3, were exposed to PM (5 mg/m3) for 7 consecutive days. In parallel, along with PM exposure, we orally administrated fucoidans (100, 400 mg/Kg) or prednisone (5 mg/Kg), an anti-inflammatory drug. We found that oral administration of fucoidans significantly attenuated PM-induced lipid peroxidation and infiltration of inflammatory cells like F4/80+ macrophages, Gr-1+ granulocytes, and CD4+ T lymphocytes. Fucoidans also attenuated the level of PM-exacerbated IL-4, a primitive cytokine released in Th2 mediated eosinophilic asthma. This further suppressed mast cell activation, degranulation and IgE synthesis of PM exposed mice. Interestingly, fucoidans attenuated PM-exacerbated mucus hypersecretion and goblet cell hyperplasia. Therefore, our results suggest that fucoidans are effective at alleviating PM-exacerbated allergic asthma symptoms by attenuating the airway inflammatory response and mucus hypersecretion.

MUC1 contributes to goblet cell metaplasia and MUC5AC expression in response to cigarette smoke in vivo

Goblet cell metaplasia (GCM) and mucin overproduction are a hallmark of chronic rhinosinusitis (CRS) and chronic obstructive pulmonary disease (COPD). In the airways, cigarette smoke (CS) induces activation of the epidermal growth factor receptor (EGFR) leading to GCM and overexpression of the gel-forming mucin MUC5AC. Although previous studies have demonstrated that a membrane-bound mucin, MUC1, modulates the activation of CS-induced EGFR, the role of MUC1 in CS-induced GCM and mucin overproduction has not been explored. In response to CS exposure, wild-type (WT) rats displayed Muc1 translocation from the apical surface of airway epithelium to the intracellular compartment of hyperplastic intermediate cells, EGFR phosphorylation, GCM, and Muc5ac overproduction. Similarly, human CRS sinonasal tissues demonstrated hyperplasia of intermediate cells enriched with MUC1 in the intracellular compartment, which was accompanied by GCM and increased MUC5AC expression. To further evaluate the role of Muc1 in vivo, a Muc1 knockout (KO) rat (MUC in humans and Muc in animals) was developed. In contrast to WT littermates, Muc1-KO rats exhibited no activation of EGFR, and were protected from GCM and Muc5ac overproduction. Genetic knockdown of MUC1 in human lung or Muc1 knockout in primary rat airway epithelial cells led to significantly diminished EGF-induced MUC5AC production. Together, these findings suggest that MUC1-dependent EGFR activation mediates CS-induced GCM and mucin overproduction. Strategies designed to suppress MUC1-dependent EGFR activation may provide a novel therapeutic approach for treating mucin hypersecretion in CRS and COPD.

A Comprehensive Systematic Review of the Association Between Airway Mucins and Chronic Rhinosinusitis

Objective

Airway mucins are the major constituents of mucus and one of the first lines of host defense against inhaled pathogens. However, aberrant expression of mucins is associated with mucus hypersecretion resulting in chronic nasal drainage, a common complaint from patients with chronic rhinosinusitis (CRS). Our goal in this systematic review was to determine (1) expression profiles, (2) regulatory mechanisms, and (3) the pathologic roles of mucins associated with CRS.

Methods

MEDLINE, Cochrane Library, Embase, Scopus, Web of Science, and ClinicalTrials.gov were searched for studies focused on the role of mucins in CRS. Quality was assessed using the Cochrane Risk of Bias tool. The full text articles selected were then categorized into 3 study groups: (1) clinical, (2) animal, and (3) in vitro cultures. Data regarding study design, population/setting, methods, and bias were extracted and synthesized.

Results

Our initial search generated 392 titles/abstracts. After the primary review, 111 articles underwent secondary review. The final review included 53 articles, including 34 articles (64%) in the clinical study group, 3 articles (6%) in the animal study group, and 16 articles (30%) in the in vitro study group. In total, aberrant expression of 8 mucins—6 secreted-mucins (MUC2, -5AC, -5B, -6, -7, and -8) and 2 membrane-bound mucins (MUC1 and -4)—were identified in CRS tissues compared to healthy controls. Mucin expression was associated with bacterial sinusitis, inflammatory markers, and the response to steroid therapy in patients with CRS with nasal polyposis.

Conclusion

There is a strong correlation between alterations in mucin expression profiles and CRS. This systematic review highlights the most recent literature on the role of mucins in CRS. The analysis of these studies is limited by the heterogeneity in study designs, relatively few numbers of clinical samples, and lack of mechanistic studies in animal models and in vitro cultures.

Fra2 Overexpression in Mice Leads to Non-allergic Asthma Development in an IL-13 Dependent Manner

Background: Asthma is a complex chronic inflammatory disease characterised by airway inflammation, remodelling and hyperresponsiveness (AHR). Members of the AP-1 transcription factor family play important roles in the activation of the immune system and the control of cellular responses; however, their role in the development of asthma has not been well studied. We aimed to investigate the role of the lesser known AP-1 family member, Fra2 in experimental asthma.

Methods: Phenotypic characterisation and gene expression profiling was performed on Fra2 (TG) overexpressing and wild-type mice. The efficacy of therapeutic interventions in regulating the Fra2 phenotype was determined.

Results: Transcriptional profiling of TG mice revealed a high abundance of regulated genes associated with airway remodelling, inflammation and mucus production. A concomitant increase in peribronchial collagen deposition, smooth muscle thickening and mucus production was observed. TG mice possessed increased inflammatory infiltration in the lung, predominantly consisting of eosinophils and T-cells and elevated expression of Th2 cytokines and eotaxin. Furthermore, TG mice possessed severe AHR in response to increasing doses of methacholine. Glucocorticoid treatment led to a partial improvement of the asthma phenotype, whereas blockade of IL-13 via neutralising antibodies ameliorated AHR and mucus production, but had no effect on collagen deposition.

Conclusion: We here describe a novel model for non-allergic asthma that does not require the application of exogenous allergens, which mimics several key features of the disease, such as airway inflammation, remodelling and hyperresponsiveness. Fra2 may represent a key molecule coordinating multiple aspects of asthma pathogenesis.

Lobeglitazone Attenuates Airway Inflammation and Mucus Hypersecretion in a Murine Model of Ovalbumin-Induced Asthma

Lobeglitazone (LB) is a novel agonist of peroxisome proliferator-activated receptor (PPAR)-α and γ that was developed as a drug to treat diabetes mellitus. We explored the ameliorative effects of LB on allergic asthma using a murine model of ovalbumin (OVA)-induced asthma. To boost the immune response of animals, OVA sensitization was performed on days 0 and 14. LB (250 or 500 μg/kg) was administered by oral gavage on days 18 to 23, and the OVA challenge was performed using an ultrasonic nebulizer on days 21 to 23. Plethysmography showed airway hyperresponsiveness (AHR) on day 24. LB treatment effectively decreased inflammatory cell recruitment, T-helper type 2 cytokines in the bronchoalveolar lavage fluid, and immunoglobulin (Ig) E in the serum of the animals with OVA-induced asthma, which was accompanied by a marked reduction in AHR. It also decreased airway inflammation, mucus hypersecretion, phosphorylation of nuclear transcription factor-kappa-B (NF-κB), and expression of activating protein (AP)-1 and mucin 5AC (MUC5AC). Overall, LB effectively attenuated the pathophysiological changes of asthma and its effects appear related to a reduction in the phosphorylation of NF-κB and the expression of AP-1. Thus, our results suggest that LB has a potential to treat allergic asthma.

Epigenetics of Mucus Hypersecretion in Chronic Respiratory Diseases

Asthma, chronic obstructive pulmonary disease, and cystic fibrosis are three chronic pulmonary diseases that affect an estimated 420 million individuals across the globe. A key factor contributing to each of these conditions is mucus hypersecretion. Although management of these diseases is vastly studied, researchers have only begun to scratch the surface of the mechanisms contributing to mucus hypersecretion. Epigenetic regulation of mucus hypersecretion, other than microRNA post-translational modification, is even more scarcely researched. Detailed study of epigenetic mechanisms, such as DNA methylation and histone modification, could not only help to better the understanding of these respiratory conditions but also reveal new treatments for them. Because mucus hypersecretion is such a complex event, there are innumerable genes involved in the process, which are beyond the scope of a single review. Therefore, the purpose of this review is to narrow the focus and summarize specific epigenetic research that has been conducted on a few aspects of mucus hypersecretion in asthma, chronic obstructive pulmonary disease, cystic fibrosis, and some cancers. Specifically, this review emphasizes the contribution of DNA methylation and histone modification of particular genes involved in mucus hypersecretion to identify possible targets for the development of future therapies for these conditions. Elucidating the role of epigenetics in these respiratory diseases may provide a breath of fresh air to millions of affected individuals around the world.

Neutrophil extracellular traps promote lipopolysaccharide-induced airway inflammation and mucus hypersecretion in mice

Bacterial lipopolysaccharide (LPS) contributes to airway inflammation and mucus hypersecretion in chronic airway inflammatory diseases, such as chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). Neutrophil extracellular traps (NETs) are extracellular meshworks composed of DNA fibers and antimicrobial proteins. Although NET formation has been detected in COPD and CF patients, how NETs contribute to these diseases is poorly understood. This study was performed to clarify the effects and mechanisms of action of NETs in airway inflammation and mucus hypersecretion. We created a murine model of LPS-induced airway inflammation and mucus hypersecretion, and found that LPS-induced NET formation was degraded by aerosolized DNase I treatment in mice. Degradation of NETs by aerosolized DNase I reduced LPS-induced airway inflammation and mucus hypersecretion in mice, this reduction correlated with suppression of TLR4/NF-κB signaling pathway. More importantly, NETs promoted LPS-induced production of IL-1β, IL-6 and TNF-α in macrophages. These results suggest NET degradation using aerosolized DNase I is a potential new therapeutic strategy for treating COPD and CF.

Preferential Generation of 15-HETE-PE Induced by IL-13 Regulates Goblet Cell Differentiation in Human Airway Epithelial Cells

Type 2-associated goblet cell hyperplasia and mucus hypersecretion are well known features of asthma. 15-Lipoxygenase-1 (15LO1) is induced by the type 2 cytokine IL-13 in human airway epithelial cells (HAECs) in vitro and is increased in fresh asthmatic HAECs ex vivo. 15LO1 generates a variety of products, including 15-hydroxyeicosatetraenoic acid (15-HETE), 15-HETE-phosphatidylethanolamine (15-HETE-PE), and 13-hydroxyoctadecadienoic acid (13-HODE). In this study, we investigated the 15LO1 metabolite profile at baseline and after IL-13 treatment, as well as its influence on goblet cell differentiation in HAECs. Primary HAECs obtained from bronchial brushings of asthmatic and healthy subjects were cultured under air-liquid interface culture supplemented with arachidonic acid and linoleic acid (10 μM each) and exposed to IL-13 for 7 days. Short interfering RNA transfection and 15LO1 inhibition were applied to suppress 15LO1 expression and activity. IL-13 stimulation induced expression of 15LO1 and preferentially generated 15-HETE-PE in vitro, both of which persisted after removal of IL-13. 15LO1 inhibition (by short interfering RNA and chemical inhibitor) decreased IL-13-induced forkhead box protein A3 (FOXA3) expression and enhanced FOXA2 expression. These changes were associated with reductions in both mucin 5AC and periostin. Exogenous 15-HETE-PE stimulation (alone) recapitulated IL-13-induced FOXA3, mucin 5AC, and periostin expression. The results of this study confirm the central importance of 15LO1 and its primary product, 15-HETE-PE, for epithelial cell remodeling in HAECs.

Hydrogen-rich saline inhibits tobacco smoke-induced chronic obstructive pulmonary disease by alleviating airway inflammation and mucus hypersecretion in rats

Chronic obstructive pulmonary disease induced by tobacco smoke has been regarded as a great health problem worldwide. The purpose of this study is to evaluate the protective effect of hydrogen-rich saline, a novel antioxidant, on chronic obstructive pulmonary disease and explore the underlying mechanism. Sprague-Dawley rats were made chronic obstructive pulmonary disease models via tobacco smoke exposure for 12 weeks and the rats were treated with 10 ml/kg hydrogen-rich saline intraperitoneally during the last 4 weeks. Lung function testing indicated hydrogen-rich saline decreased lung airway resistance and increased lung compliance and the ratio of forced expiratory volume in 0.1 s/forced vital capacity in chronic obstructive pulmonary disease rats. Histological analysis revealed that hydrogen-rich saline alleviated morphological impairments of lung in tobacco smoke-induced chronic obstructive pulmonary disease rats. ELISA assay showed hydrogen-rich saline lowered the levels of pro-inflammatory cytokines (IL-8 and IL-6) and anti-inflammatory cytokine IL-10 in bronchoalveolar lavage fluid and serum of chronic obstructive pulmonary disease rats. The content of malondialdehyde in lung tissue and serum was also determined and the data indicated hydrogen-rich saline suppressed oxidative stress reaction. The protein expressions of mucin MUC5C and aquaporin 5 involved in mucus hypersecretion were analyzed by Western blot and ELISA and the data revealed that hydrogen-rich saline down-regulated MUC5AC level in bronchoalveolar lavage fluid and lung tissue and up-regulated aquaporin 5 level in lung tissue of chronic obstructive pulmonary disease rats. In conclusion, these results suggest that administration of hydrogen-rich saline exhibits significant protective effect on chronic obstructive pulmonary disease through alleviating inflammation, reducing oxidative stress and lessening mucus hypersecretion in tobacco smoke-induced chronic obstructive pulmonary disease rats. Impact statement This study was designed to evaluate protective effect of hydrogen-rich saline, a novel antioxidant, on tobacco smoke (TS)-induced chronic obstructive pulmonary disease (COPD) in rats and explore the underlying mechanism. Our results suggest that administration of hydrogen-rich saline improves lung function and alleviates morphological impairments of lung through alleviating inflammation, reducing oxidative stress and lessening mucus hypersecretion in TS-induced COPD rats.

Therapeutic Effects of Resveratrol in a Mouse Model of LPS and Cigarette Smoke-Induced COPD

This study was designed to examine whether resveratrol exerts the protective effects on LPS and cigarette smoke (LC)-induced COPD in a murine model. In lung histopathological studies, H&E, Masson's trichrome, and AB-PAS staining were performed. The cytokines (IL-6, IL-17, TGF-β, and TNF-α) and inflammatory cells in BALF were determined. The Beclin1 level in the lungs of mouse was analyzed. Compared with the LC-induced mouse, the level of inflammatory cytokines (IL-17, IL-6, TNF-α, and TGF-β) of the BALF in the resveratrol + cigarette smoke-treated mouse had obviously decreased. Histological examination of the lung tissue revealed that the resveratrol treatment attenuated the fibrotic response and mucus hypersecretion. In addition, resveratrol inhibited the expression of the Beclin1 protein in mouse lungs. The presented findings collectively suggest that resveratrol has a therapeutic effect on mouse LC-induced COPD, and its mechanism of action might be related to reducing the production of the Beclin1 protein.

Rho-kinase inhibitor fasudil reduces allergic airway inflammation and mucus hypersecretion by regulating STAT6 and NFκB

BACKGROUND

Airway mucus hypersecretion is a key pathophysiological feature in asthma. Fasudil, a selective Rho-A/Rho kinase inhibitor, has been used in clinical trials to treat pulmonary hypertension. However, its function in modulating airway mucus hypersecretion in asthma remains undefined.

OBJECTIVE

We examined whether fasudil, a selective Rho-A/Rho kinase inhibitor, affects the mucus hypersecretion by suppressing MUC5AC via signal transducer and activator of transcription factor 6 (STAT6) and nuclear factor-kappa B (NFκB) in mice and cells.

METHODS

We measured mucus secretion and the expression of Rho-kinase in the airway tissue of patients with asthma. BALB/c mice were sensitized and challenged with ovalbumin (OVA) followed with fasudil treatment. The lung tissues were assessed for airway inflammation and mucus secretion. Cytokine levels and airway responsiveness were determined. STAT6 and NFκB were quantified by Western blot. 16HBE cells were stimulated with house dust mite (HDM) extracts. MUC5AC and muc5ac promoter activities were measured. Using siRNA to knockdown STAT6 in epithelial cells, we determined the impact of STAT6 on muc5ac promoter activity. NFκB nuclear translocation was observed with immunostaining.

RESULTS

Fasudil administration significantly decreased the number of inflammatory cells, inflammation index in the lung and airway responsiveness. Fasudil also reduced mucous secretion and MUC5AC expression in OVA-challenged mice. Fasudil down-regulated the levels of IL-17, IL-4 and IL-13 in the lung tissue of OVA-challenged mice. Fasudil also decreased the expression and phosphorylation of NFκB and STAT6 as well as the nuclear translocation of NFκB. In addition, human airway epithelial cells (16HBE) were challenged with HDM extracts and then treated with fasudil. Fasudil inhibited HDM extract-induced MUC5AC expression, which is associated with a reduction in STAT6 and NFκB in epithelial cells.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings indicate that the Rho-A/Rho kinase inhibitor, fasudil, plays a negative regulatory role in allergen-induced mucus secretion and MUC5AC expression by regulating STAT6 and NFκB.

Clinical significance of airway mucus hypersecretion in chronic obstructive pulmonary disease

Airway mucus hypersecretion is one of the most important features of chronic obstructive pulmonary disease (COPD). Airway mucus hypersecretion in COPD patients results in outcomes such as rapid decline of lung function, poor quality of life, and high rate of acute exacerbation, hospitalization and mortality. Nonpharmacologic treatments for airway mucus hypersecretion in COPD include smoking cessation and physical rehabilitation. Pharmacologic therapies include expectorants, mucolytics, methylxanthines, beta-adrenergic receptor agonists, anticholinergics, glucocorticoids, phosphodiesterase-4 inhibitors, antioxidants, and antibiotics. Novel drugs with promising prospects are currently under clinical trials.