Inhibition of TNF-α-induced MUC5AC mucin gene expression and production by wogonin through the inactivation of NF-κB signaling in airway epithelial cells

Inhibition of transient receptor potential vanilloid 1 reduces shedding and transmission during Streptococcus pneumoniae co-infection with influenza

Transmission is the first step for a microorganism to establish colonization in the respiratory tract and subsequent development of infectious disease. Streptococcus pneumoniae is a leading pathogen that colonizes the mucosal surfaces of the human upper respiratory tract and causes subsequent transmission and invasive infections especially in co-infection with influenza A virus. Host factors contributing to respiratory contagion are poorly understood. Transient receptor potential vanilloid (TRPV) channels have various roles in response to microoorganism. Inhibition of TRPV exacerbates invasive infection by Streptococcus pneumoniae, but it is unclear how TRPV channels influence pneumococcal transmission. Here, we describe the effect of inhibition of TRPV1 on pneumococcal transmission. We adopted a TRPV1-deficient infant mouse model of pneumococcal transmission during co-infection with influenza A virus. We also analyzed the expression of nasal mucin or pro-inflammatory cytokines. TRPV1 deficiency attenuated pneumococcal transmission and shedding during co-infection with influenza A virus. TRPV1 deficiency suppressed the expression of nasal mucin. In addition, there were increases in the expression of tumor necrosis factor-α and type I interferon, followed by the suppressed replication of influenza A virus in TRPV1-deficient mice. Inhibition of TRPV1 was shown to attenuate pneumococcal transmission by reducing shedding through the suppression of nasal mucin during co-infection with influenza A virus. Inhibition of TRPV1 suppressed nasal mucin by modulation of pro-inflammatory responses and regulation of replication of influenza A virus. TRPV1 could be a new target in preventive strategy against pneumococcal transmission.

Characteristics of mucin hypersecretion in different inflammatory patterns based on endotypes of chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is usually accompanied by mucin hypersecretion that can lead to mucus accumulation and impair nasal mucociliary clearance, thus exacerbating airway inflammation. Abnormal mucin hypersecretion is regulated by different T helper (Th) cytokines, which are associated with different endotype-driven inflammatory responses. Therefore, it is of great significance to understand how these factors regulate mucin hypersecretion to provide precise treatment strategies for different endotypes of CRS. BODY: Thus far, the most common endotypes of CRS are classified as type 1, type 2, or type 3 immune responses based on innate and adaptive cell-mediated effector immunity, and the representative Th cytokines in these immune responses, such as IFN-γ, TNF-α, IL-4, IL-5, IL-13, IL-10, IL-17, and IL-22, play an important regulatory role in mucin secretion. We reviewed all the related literature in the PubMed database to determine the expression of these Th cytokines in CRS and the role they play in the regulation of mucin secretion.

CONCLUSION

We believe that the main Th cytokines involved in specific endotypes of CRS play a key role in regulating abnormal mucin secretion, which contributes to better understanding of the pathogenesis of CRS and provides therapeutic targets for airway inflammatory diseases associated with mucin hypersecretion.

Role of the cAMP-PKA-NF-κB pathway in Mucin1 over-expression in A549 cells during Respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the most common pathogen associated with acute lower respiratory tract infections in infants and young children worldwide. RSV commonly presents as bronchiolitis in young children; however, it can sometimes progress to pneumonia, respiratory failure, apnoea and even death. Although mucin1 (MUC1), a type of transmembrane glycoprotein present on airway epithelial surfaces, plays a crucial anti-inflammatory role in airway infections; however, its roles in RSV-associated acute lower respiratory tract infections have rarely been explored. In this study, we first revealed very high MUC1 protein levels in the exacerbation phase in sputum samples from children with RSV bronchiolitis. Because MUC1 is the downstream target of tumour necrosis factor-alpha (TNF-α) in RSV-infected A549 cells, we observed the inhibition of NF-κB activity, main downstream signalling of TNF-α and remarkably reduced levels of MUC1 in RSV-infected and TNF-α treated A549 cells. Furthermore, the cyclic adenosine monophosphate (cAMP) analogue (dbcAMP) downregulated the protein levels of p-IκBα and MUC1 in TNF-α-treated A549 cells. By contrast, a protein kinase A inhibitor (KT5720) up-regulated the levels of those proteins. dbcAMP and KT5720 had the same effects on MUC1 protein levels in RSV-infected A549 cells. In conclusion, we found that the cAMP-PKA-NF-κB pathway may play a role in the regulation of MUC-1 over-expression during RSV infection.

Regulation of the Gene Expression of Airway MUC5AC Mucin through NF-κB Signaling Pathway by Artesunate, an Antimalarial Agent

In this study, artesunate, an antimalarial agent, was investigated for its potential effect on the gene expression of airway MUC5AC mucin. The human pulmonary epithelial NCI-H292 cells were pretreated with artesunate for 30 min and then stimulated with phorbol 12-myristate 13-acetate (PMA), for the following 24 h. The effect of artesunate on PMA-induced nuclear factor kappa B (NF-kB) signaling pathway was also examined. Artesunate inhibited the glycoprotein production and mRNA expression of MUC5AC mucins, induced by PMA through the inhibition of degradation of inhibitory kappa Bα (IkBα) and NF-kB p65 nuclear translocation. These results suggest artesunate suppresses the gene expression of mucin through regulation of NF-kB signaling pathway, in human pulmonary epithelial cells.

Integrative Approach to Identifying System-Level Mechanisms of Chung-Sang-Bo-Ha-Hwan's Influence on Respiratory Tract Diseases: A Network Pharmacological Analysis with Experimental Validation

Chung-Sang-Bo-Ha-Hwan (CSBHH) is an herbal prescription widely used to treat various chronic respiratory diseases. To investigate the system-level treatment mechanisms of CSBHH in respiratory tract diseases, we identified 56 active ingredients of CSBHH and evaluated the degree of overlap between their targets and respiratory tract disease-associated proteins. We then investigated the respiratory tract disease-related signaling pathways associated with CSBHH targets. Enrichment analysis showed that the CSBHH targets were significantly associated with various signaling pathways related to inflammation, alveolar structure, and tissue fibrosis. Experimental validation was conducted using phorbol-12-myristate-13-acetate (PMA)-stimulated NCI-H292 cells by analyzing the mRNA expression levels of biomarkers (IL-1β and TNF-α for inflammation; GSTP1, GSTM1, and PTEN for apoptosis) derived from network pharmacological analysis, in addition to the mucin genes MUC5AC and MUC2, to investigate the phlegm-expelling effect of CSBHH. The mRNA expression levels of these genes were consistent with network pharmacological predictions in a concentration-dependent manner. These results suggest that the therapeutic mechanisms of CSBHH in respiratory tract diseases could be attributed to the simultaneous action of multiple active ingredients in the herbal prescription.

Effect of Paeoniae Radix Rubra (Paeonia lactiflora Pall.) extract on mucin secretion, gene expression in human airway epithelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniae Radix Rubra (PRR), the root of Paeonia lactiflora Pall., is a traditional Chinese medicine which has the effects of regulating various inflammatory diseases, treating blood stasis, and enhancing blood circulation.

AIM OF THE STUDY

This study examined whether Paeoniae Radix rubra extract (PRRE) and Paeoniflorin (PF) affect mucin production, gene expression including MUC5AC, and protein expression related to the ERK pathway induced by TNF-α from human airway epithelial cells.

MATERIALS AND METHODS

NCI-H292 cells induced by TNF-α were treated with each agent. MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription polymerase chain reaction, staining, and enzyme-linked immunosorbent assay. Western blot was used to investigate the cell signaling pathways.

RESULTS

PRRE and PF inhibited the production of MUC5AC mucin protein and gene expression in TNF-α-induced H292 cells. In Western blot, PRRE was involved in protein expression related to the ERK pathway.

CONCLUSIONS

Overall, PRRE effectively inhibited the MUC5AC, and inflammatory cytokines expression caused by TNF-α, which was closely involved in the ERK pathway. PRRE may have the potential for treating mucus producing respiratory inflammation.

Network Pharmacological Analysis on the Herbal Combinations for Mitigating Inflammation in Respiratory Tracts and Experimental Evaluation

The regulation of inflammatory mediators, such as TNF-α, IL-6, IL-1β, and leukotriene B4, could play a crucial role in suppressing inflammatory diseases such as COVID-19. In this study, we investigated the potential mechanisms of drug combinations comprising Ephedrae Herba, Schisandra Fructus, Platycodonis Radix, and Ginseng Radix; validated the anti-inflammatory effects of these drugs; and determined the optimal dose of the drug combinations. By constructing a herb-compound-target network, associations were identified between the herbs and tissues (such as bronchial epithelial cells and lung) and pathways (such as the TNF, NF-κB, and calcium signaling pathways). The drug combinations exerted anti-inflammatory effects in the RAW264.7 cell line treated with lipopolysaccharide by inhibiting the production of nitric oxide and inflammatory mediators, including TNF-α, IL-6, IL-1β, and leukotriene B4. Notably, the drug combinations inhibited PMA-induced MUC5AC mRNA expression in NCI-H292 cells. A design space analysis was carried out to determine the optimal herbal medicine combinations using the design of experiments and synergy score calculation. Consequently, a combination study of the herbal preparations confirmed their mitigating effect on inflammation in COVID-19.

Qingfei Jiedu decoction inhibits PD-L1 expression in lung adenocarcinoma based on network pharmacology analysis, molecular docking and experimental verification

Objective: We aim at investigating the molecular mechanisms through which the Qingfei Jiedu decoction (QFJDD) regulates PD-L1 expression in lung adenocarcinoma (LUAD).

Methods: Bioactive compounds and targets of QFJDD were screened from TCMSP, BATMAN-TCM, and literature. Then, GeneCard, OMIM, PharmGKB, Therapeutic Target, and DrugBank databases were used to identify LUAD-related genes. The protein-protein interaction (PPI) network was constructed using overlapping targets of bioactive compounds in LUAD with the Cytoscape software and STRING database. The potential functions and pathways in which the hub genes were enriched by GO, KEGG, and DAVID pathway analyses. Molecular docking of bioactive compounds and key genes was executed via AutoDock Vina. Qualitative and quantitative analyses of QFJDD were performed using UPLC-Q-TOF-MS and UPLC. Expressions of key genes were determined by qRT-PCR, immunoreactivity score (IRS) of PD-L1 was assessed by immunohistochemistry (IHC), while the CD8⁺PD-1⁺T% derived from spleen tissues of Lewis lung cancer (LLC) bearing-mice was calculated using flow cytometry (FCM).

Results: A total of 53 bioactive compounds and 288 targets of QFJDD as well as 8151 LUAD associated genes were obtained. Further, six bioactive compounds, including quercetin, luteolin, kaempferol, wogonin, baicalein, and acacetin, and 22 hub genes were identified. The GO analysis showed that the hub genes were mainly enriched in DNA or RNA transcription. KEGG and DAVID pathway analyses revealed that 20 hub genes were primarily enriched in virus, cancer, immune, endocrine, and cardiovascular pathways. The EGFR, JUN, RELA, HIF1A, NFKBIA, AKT1, MAPK1, and MAPK14 hub genes were identified as key genes in PD-L1 expression and PD-1 checkpoint pathway. Moreover, ideal affinity and regions were identified between core compounds and key genes. Notably, QFJDD downregulated EGFR, JUN, RELA, HIF1A, NFKBIA, and CD274 expressions (p < 0.05), while it upregulated AKT1 and MAPK1 (p < 0.05) levels in A549 cells. The PD-L1 IRS of LLC tissue in the QFJDD high dose (H_d) group was lower than model group (p < 0.01). CD8⁺PD-1⁺T% was higher in the QFJDD H_d group than in normal and model groups (p < 0.05).

Conclusion: QFJDD downregulates PD-L1 expression and increases CD8⁺PD-1⁺T% via regulating HIF-1, EGFR, JUN and NFκB signaling pathways. Therefore, QFJDD is a potential treatment option for LUAD.

Black Ginseng Extract Suppresses Airway Inflammation Induced by Cigarette Smoke and Lipopolysaccharides In Vivo

Cigarette smoke (CS) is a risk factor that can induce airway enlargement, airway obstruction, and airway mucus hypersecretion. Although studies have shown that Korean black ginseng extract (BGE) has potent anti-inflammatory and antioxidant activities, the CS-induced inflammatory responses and molecular mechanisms are yet to be examined. The aim of this study was to examine the effect of BGE on the airway inflammatory response and its molecular mechanisms, using CS/lipopolysaccharides (LPS)-exposed animals and PMA-stimulated human airway epithelial NCI-H292 cells. The results show that BGE inhibited the recruitment of immune cells and the release of inflammatory mediators, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, elastase, and reactive oxygen species (ROS) in the airways of CS/LPS-exposed animals. BGE inhibited mucus secretion and the expression of Mucin 5AC (MUC5AC). Furthermore, BGE exhibited an anti-inflammatory effect by downregulating a signaling pathway mediated by transforming growth factor-β-activated kinase (TAK) 1, an important protein that accelerates inflammation by cigarette smoke (CS). Overall, the findings show that BGE inhibits lung inflammation and mucus secretion by decreasing the activation of TAK1 both in human epithelial cells and in CS/LPS-exposed animals, and could be a potential adjuvant in the treatment and prevention of airway inflammatory diseases caused by airway irritants such as CS.

Tumor necrosis factor-α promotes airway mucus hypersecretion by repressing miR-146a-5p and miR-134-5p levels in human airway epithelial cells

Background

Airway mucus acts as an indispensable protective component of innate immune response against invading pathogens. However, airway mucus hypersecretion, largely consisting of mucin 5AC (MUC5AC), is the leading cause of airflow obstruction and airway hyperresponsiveness that contributes to chronic obstructive pulmonary disease (COPD). MicroRNAs (miRNAs) are frequently dysregulated in the pathogenesis of COPD, but the definite role of miRNAs in airway mucus hypersecretion is not well understood.

Methods

A cell model of mucus hypersecretion was established in 16HBE cells by treatment with TNF-α. Cell viability and apoptosis were assessed using cell counting kit-8 (CCK-8) and flow cytometry, respectively. The aberrant expression of miR-146a-5p and miR-134-5p was assayed in TNF-α-treated 16HBE cells, and the effect of miR-146a-5p and miR-134-5p on regulating MUC5AC expression was evaluated using quantitative real-time PCR (qPCR) and Western blot analysis.

Results

TNF-α treatment resulted in a significant decrease of cell viability, and increase of cell apoptosis and MUC5AC expression in 16HBE cells. Additionally, the expression of miR-134-5p and miR-146a-5p was markedly decreased in the cell model. Importantly, forced expression of miR-134-5p and miR-146a-5p significantly repressed TNF-α-induced upregulation of MUC5AC. Mechanistically, although miR-134-5p did not affect 16HBE cells viability and apoptosis, miR-134-5p partially blocked TNF-α-induced MUC5AC expression by inhibiting the activation of NF-κB signaling. On the other hand, miR-146a-5p enhanced cell viability and reduced cell apoptosis. miR-146a-5p also repressed TNF-α-induced MUC5AC expression by inhibiting p38 MAPK (mitogen-activated protein kinase) signaling activation.

Conclusions

The current data demonstrated that both miR-134-5p and miR-146a-5p conferred protection against TNF-α-induced mucus hypersecretion through repressing NF-κB and p38 MAPK signaling, indicating that miR-134-5p and miR-146a-5p may serve as the biomarker for COPD.

Kaempferol Regulates the Expression of Airway MUC5AC Mucin Gene via IκBα-NF-κB p65 and p38-p44/42-Sp1 Signaling Pathways

In the present study, kaempferol, a flavonoidal natural compound found in Polygonati Rhizoma, was investigated for its potential effect on the gene expression and production of airway MUC5AC mucin. A human respiratory epithelial NCI-H292 cells was pretreated with kaempferol for 30 min and stimulated with epidermal growth factor (EGF) or phorbol 12-myristate 13-acetate (PMA), for the following 24 h. The effect on PMA-induced nuclear factor kappa B (NF-κB) signaling pathway or EGF-induced mitogen-activated protein kinase (MAPK) signaling pathway was investigated. Kaempferol suppressed the production and gene expression of MUC5AC mucins, induced by PMA through the inhibition of degradation of inhibitory kappa Bα (IκBα), and NF-κB p65 nuclear translocation. Also, kaempferol inhibited EGF-induced gene expression and production of MUC5AC mucin through regulating the phosphorylation of EGFR, phosphorylation of p38 MAPK and extracellular signal-regulated kinase (ERK) 1/2 (p44/42), and the nuclear expression of specificity protein-1 (Sp1). These results suggest kaempferol regulates the gene expression and production of mucin through regulation of NF-κB and MAPK signaling pathways, in human airway epithelial cells.

Transforming Growth Factor β Inhibits MUC5AC Expression by Smad3/HDAC2 Complex Formation and NF-κB Deacetylation at K310 in NCI-H292 Cells

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of the gel- forming MUC5AC protein, are significant risk factors for patients with asthma and chronic obstructive pulmonary disease (COPD). The transforming growth factor β (TGFβ) signaling pathway negatively regulates MUC5AC expression; however, the underlying molecular mechanism is not fully understood. Here, we showed that TGFβ significantly reduces the expression of MUC5AC mRNA and its protein in NCI-H292 cells, a human mucoepidermoid carcinoma cell line. This reduced MUC5AC expression was restored by a TGFβ receptor inhibitor (SB431542), but not by the inhibition of NF-κB (BAY11-7082 or Triptolide) or PI3K (LY294002) activities. TGFβ-activated Smad3 dose-dependently bound to MUC5AC promoter. Notably, TGFβ-activated Smad3 recruited HDAC2 and facilitated nuclear translocation of HDAC2, thereby inducing the deacetylation of NF-κB at K310, which is essential for a reduction in NF-κB transcriptional activity. Both TGFβ-induced nuclear translocation of Smad3/HDAC2 and deacetylation of NF-κB at K310 were suppressed by a Smad3 inhibitor (SIS3). These results suggest that the TGFβ-activated Smad3/HDAC2 complex is an essential negative regulator for MUC5AC expression and an epigenetic regulator for NF-κB acetylation. Therefore, these results collectively suggest that modulation of the TGFβ1/Smad3/HDAC2/NF-κB pathway axis can be a promising way to improve lung function as a treatment strategy for asthma and COPD.

Diclofenac Inhibits Phorbol Ester-Induced Gene Expression and Production of MUC5AC Mucin via Affecting Degradation of IkBα and Translocation of NF-kB p65 in NCI-H292 Cells

In this study, diclofenac, a non-steroidal anti-inflammatory drug, was investigated for its potential effect on the gene expression and production of airway MUC5AC mucin. The human respiratory epithelial NCI-H292 cells were pretreated with diclofenac for 30 min and stimulated with phorbol 12-myristate 13-acetate (PMA), for the following 24 h. The effect of diclofenac on PMA-induced nuclear factor kappa B (NF-kB) signaling pathway was also investigated. Diclofenac suppressed the production and gene expression of MUC5AC mucins, induced by PMA through the inhibition of degradation of inhibitory kappa Bα (IkBα) and NF-kB p65 nuclear translocation. These results suggest diclofenac regulates the gene expression and production of mucin through regulation of NF-kB signaling pathway, in human airway epithelial cells.

Recent Advances in the Development of Novel Drug Candidates for Regulating the Secretion of Pulmonary Mucus

Hypersecretion of pulmonary mucus is a major pathophysiological feature in allergic and inflammatory respiratory diseases including asthma and chronic obstructive pulmonary disease (COPD). Overproduction and/or oversecretion of mucus cause the airway obstruction and the colonization of pathogenic microbes. Developing a novel pharmacological agent to regulate the production and/or secretion of pulmonary mucus can be a useful strategy for the effective management of pathologic hypersecretion of mucus observed in COPD and asthma. Thus, in the present review, we tried to give an overview of the conventional pharmacotherapy for mucus-hypersecretory diseases and recent research results on searching for the novel candidate agents for controlling of pulmonary mucus hypersecretion, aiming to shed light on the potential efficacious pharmacotherapy of mucus-hypersecretory diseases.

Genomic Variants Among Threatened Acropora Corals

Genomic sequence data for non-model organisms are increasingly available requiring the development of efficient and reproducible workflows. Here, we develop the first genomic resources and reproducible workflows for two threatened members of the reef-building coral genus Acropora We generated genomic sequence data from multiple samples of the Caribbean A. cervicornis (staghorn coral) and A. palmata (elkhorn coral), and predicted millions of nucleotide variants among these two species and the Pacific A. digitifera A subset of predicted nucleotide variants were verified using restriction length polymorphism assays and proved useful in distinguishing the two Caribbean acroporids and the hybrid they form ("A. prolifera"). Nucleotide variants are freely available from the Galaxy server (usegalaxy.org), and can be analyzed there with computational tools and stored workflows that require only an internet browser. We describe these data and some of the analysis tools, concentrating on fixed differences between A. cervicornis and A. palmata In particular, we found that fixed amino acid differences between these two species were enriched in proteins associated with development, cellular stress response, and the host's interactions with associated microbes, for instance in the ABC transporters and superoxide dismutase. Identified candidate genes may underlie functional differences in how these threatened species respond to changing environments. Users can expand the presented analyses easily by adding genomic data from additional species, as they become available.

Curcumin suppresses MUC5AC production via interfering with the EGFR signaling pathway

Excessive mucin production in the airway may contribute to airway inflammatory diseases. Curcumin has been reported to prevent mucin 5AC (MUC5AC) production in human airway epithelial cells; however, the molecular targets of curcumin involved in regulating MUC5AC expression have remained elusive. The present study aimed to elucidate the molecular mechanisms by which curcumin regulates MUC5AC production, utilizing the NCI‑H292 human airway epithelial cell line featuring MUC5AC hypersecretion. Curcumin was able to counteract the endothelial growth factor (EGF)‑stimulated mRNA and protein expression of MUC5AC. In addition, curcumin treatment prevented EGF‑induced phosphorylation of EGF receptor (EGFR) as well as the downstream AKT and signal transducer and activator of transcription 3 (STAT3), while inhibition of PI3K and STAT3 signaling significantly attenuated the expression of MUC5AC that was induced by EGF. Furthermore, EGF‑induced increases in the levels of phosphorylated STAT3 in the nuclear fraction were inhibited by curcumin and PI3K inhibitors. In addition, treatment with curcumin significantly decreased MUC5AC and EGFR expression in a time‑dependent manner under basal conditions. These results demonstrated that curcumin inhibited MUC5AC protein expression in NCI‑H292 cells under basal conditions as well under EGF stimulation. This inhibition was accompanied by decreased activation of the EGFR/AKT/STAT3 pathway and reduced EGFR expression, which indicated that curcumin may have a dual role in interfering with the EGFR signaling pathway and inhibiting mucin expression in human airway epithelial cells.

Piscroside C inhibits TNF-α/NF-κB pathway by the suppression of PKCδ activity for TNF-RSC formation in human airway epithelial cells

BACKGROUND

Piscroside C, isolated from Pseudolysimachion rotundum var. subintegrum, is a novel iridoid glycoside with therapeutic efficacy in a mouse model of chronic obstructive pulmonary disease (COPD). Piscroside C has been reported as a constituent of YPL-001 (under Phase 2a study, ClinicalTrials.gov identifier NCT02272634).

PURPOSE

To investigate the mechanisms behind piscroside C therapeutic effects on COPD in human airway epithelial NCI-H292 cells.

METHODS

We tested if piscroside C effectively suppresses MUC5AC gene expression and TNF-RSC/IKK/NF-κB cascades in TNF-α-stimulated NCI-H292 cells by employing, reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, luciferase reporter assays, chromatin immunoprecipitation assays and immunoprecipitation.

RESULTS

Piscroside C markedly suppressed the expression of TNF-α-induced MUC5AC mucus protein by inhibiting the transcriptional activity of NF-κB in NCI-H292 cells. Indeed, piscroside C negatively regulated the function of TNF receptor 1 signaling complex (TNF-RSC, an upstream regulator of the NF-κB pathway) without affecting its extracellular interaction with the TNF-α ligand. This inhibitory effect by piscroside C is mediated by the inactivation of protein kinase C (PKC), an essential regulator of TNF-RSC. PKC inactivation by piscroside C results in decreased PKCδ binding to a TRAF2 subunit of TNF-RSC and subsequent reduced IKK phosphorylation, resulting in NF-κB inactivation.

CONCLUSION

We propose that piscroside C is a promising therapeutic constituent of YPL-001 through its inhibition of PKCδ activity in the TNF-RSC/IKK/NF-κB/MUC5AC signaling cascade.

Plant flavones enhance antimicrobial activity of respiratory epithelial cell secretions against Pseudomonas aeruginosa

Flavones are a class of natural plant secondary metabolites that have anti-inflammatory and anti-bacterial effects. Some flavones also activate the T2R14 bitter taste receptor, which is expressed in motile cilia of the sinonasal epithelium and activates innate immune nitric oxide (NO) production. Flavones may thus be potential therapeutics for respiratory infections. Our objective was to examine the anti-microbial effects of flavones on the common sinonasal pathogens Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa, evaluating both planktonic and biofilm growth. Flavones had only very low-level antibacterial activity alone. They did not reduce biofilm formation, but did reduce production of the important P. aeruginosa inflammatory mediator and ciliotoxin pyocyanin. However, flavones exhibited synergy against P. aeruginosa in the presence of antibiotics or recombinant human lysozyme. They also enhanced the efficacy of antimicrobials secreted by cultured and primary human airway cells grown at air-liquid interface. This suggests that flavones may have anti-gram-negative potential as topical therapeutics when combined with antibiotics or in the context of innate antimicrobials secreted by the respiratory or other epithelia. This may have an additive effect when combined with T2R14-activated NO production. Additional studies are necessary to understand which flavone compounds or mixtures are the most efficacious.

Flavones modulate respiratory epithelial innate immunity: Anti-inflammatory effects and activation of the T2R14 receptor

Chronic rhinosinusitis has a significant impact on patient quality of life, creates billions of dollars of annual healthcare costs, and accounts for ∼20% of adult antibiotic prescriptions in the United States. Because of the rise of resistant microorganisms, there is a critical need to better understand how to stimulate and/or enhance innate immune responses as a therapeutic modality to treat respiratory infections. We recently identified bitter taste receptors (taste family type 2 receptors, or T2Rs) as important regulators of sinonasal immune responses and potentially important therapeutic targets. Here, we examined the immunomodulatory potential of flavones, a class of flavonoids previously demonstrated to have antibacterial and anti-inflammatory effects. Some flavones are also T2R agonists. We found that several flavones inhibit Muc5AC and inducible NOS up-regulation as well as cytokine release in primary and cultured airway cells in response to several inflammatory stimuli. This occurs at least partly through inhibition of protein kinase C and receptor tyrosine kinase activity. We also demonstrate that sinonasal ciliated epithelial cells express T2R14, which closely co-localizes (<7 nm) with the T2R38 isoform. Heterologously expressed T2R14 responds to multiple flavones. These flavones also activate T2R14-driven calcium signals in primary cells that activate nitric oxide production to increase ciliary beating and mucociliary clearance. TAS2R38 polymorphisms encode functional (PAV: proline, alanine, and valine at positions 49, 262, and 296, respectively) or non-functional (AVI: alanine, valine, isoleucine at positions 49, 262, and 296, respectively) T2R38. Our data demonstrate that T2R14 in sinonasal cilia is a potential therapeutic target for upper respiratory infections and that flavones may have clinical potential as topical therapeutics, particularly in T2R38 AVI/AVI individuals.

Verproside inhibits TNF-α-induced MUC5AC expression through suppression of the TNF-α/NF-κB pathway in human airway epithelial cells

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of MUC5AC, are significant risk factors in asthma and chronic obstructive pulmonary disease (COPD) patients. Previously, we reported that verproside, a catalpol derivative iridoid glycoside isolated from Pseudolysimachion rotundum var. subintegrum, is a potent anti-asthmatic candidate drug in vivo. However, the molecular mechanisms underlying the pharmacological actions of verproside remain unknown. Here, we found that verproside significantly reduces the expression levels of tumor necrosis factor alpha (TNF-α)-induced MUC5AC mRNA and protein by inhibiting both nuclear factor kappa B (NF-κB) transcriptional activity and the phosphorylation of its upstream effectors such as IκB kinase (IKK)β, IκBα, and TGF-β-activated kinase 1 (TAK1) in NCI-H292 cells. Moreover, verproside attenuated TNF-α-induced MUC5AC transcription more effectively when combined with an IKK (BAY11-7082) or a TAK1 (5z-7-oxozeaenol) inhibitor than when administered alone. Importantly, we demonstrated that verproside negatively modulates the formation of the TNF-α-receptor (TNFR) 1 signaling complex [TNF-RSC; TNFR1-recruited TNFR1-associated death domain protein (TRADD), TNFR-associated factor 2 (TRAF2), receptor-interacting protein kinase 1 (RIP1), and TAK1], the most upstream signaling factor of NF-κB signaling. In silico molecular docking studies show that verproside binds between TRADD and TRAF2 subunits. Altogether, these results suggest that verproside could be a good therapeutic candidate for treatment of inflammatory airway diseases such as asthma and COPD by blocking the TNF-α/NF-κB signaling pathway.

Apigenin Inhibits Tumor Necrosis Factor-α-Induced Production and Gene Expression of Mucin through Regulating Nuclear Factor-Kappa B Signaling Pathway in Airway Epithelial Cells

In the present study, we investigated whether apigenin significantly affects tumor necrosis factor-α (TNF-α)-induced production and gene expression of MUC5AC mucin in airway epithelial cells. Confluent NCI-H292 cells were pretreated with apigenin for 30 min and then stimulated with TNF-α for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription - polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Apigenin significantly inhibited MUC5AC mucin production and down-regulated MUC5AC gene expression induced by TNF-α in NCI-H292 cells. To elucidate the action mechanism of apigenin, effect of apigenin on TNF-α-induced nuclear factor kappa B (NF-κB) signaling pathway was also investigated by western blot analysis. Apigenin inhibited NF-κB activation induced by TNF-α. Inhibition of inhibitory kappa B kinase (IKK) by apigenin led to the suppression of inhibitory kappa B alpha (IκBα) phosphorylation and degradation, p65 nuclear translocation. This, in turn, led to the down-regulation of MUC5AC protein production in NCI-H292 cells. Apigenin also has an influence on upstream signaling of IKK because it inhibited the expression of adaptor protein, receptor interacting protein 1 (RIP1). These results suggest that apigenin can regulate the production and gene expression of mucin through regulating NF-κB signaling pathway in airway epithelial cells.

Triptolide suppresses airway goblet cell hyperplasia and Muc5ac expression via NF-κB in a murine model of asthma

BACKGROUND

We have reported that triptolide inhibited pulmonary inflammation in patients with steroid-resistant asthma. In the present study, we investigated whether suppresses airway remodeling and goblet cell hyperplasia, studied the mechanism of triptolide on mucin5ac (Muc5ac) expression in a murine model of asthma.

METHODS

BALB/c mice were sensitized to intraperitoneal ovalbumin (OVA) followed by repetitive ovalbumin challenge for 6 weeks. Treatments included triptolide (40 μg/kg) and dexamethasone (2mg/kg). The area of bronchial airway (WAt/Pbm), smooth muscle (WAm/Pbm) and mucus index were assessed 24h after the final OVA challenge. Levels of Muc5ac were assessed by ELISA, immunohistology and real-time PCR. Western blot was performed to analyze the phosphorylation of NF-κB p65.

RESULTS

Triptolide and dexamethasone significantly reduced allergen-induced increases in the thickness of bronchial airway, smooth muscle and goblet cell hyperplasia. Levels of lung Muc5ac and Muc5ac mRNA were significantly reduced in mice treated with triptolide and dexamethasone. Phosphorylation of NF-κB p65 was significantly reduced in mice treated with triptolide and dexamethasone.

CONCLUSION

Triptolide may inhibit airway goblet cell hyperplasia and Muc5ac expression in asthmatic mice via NF-κB. It may be a potential drug for the treatment of patients with severe asthma.

Adalimumab Treatment in Biologically Naïve Crohn's Disease: Relationship with Ectopic MUC5AC Expression and Endoscopic Improvement

Background. Adalimumab (ADA) is effective for patients with Crohn's disease (CD). However, there have been few reports on ADA therapy with respect to its relationship with pathologic findings and drug efficacy in biologically naïve CD cases. Methods. Fifteen patients with active biologically naïve CD were treated with ADA. We examined them clinically and pathologically with ectopic MUC5AC expression in the lesions before and after 12 and 52 weeks of ADA therapy, retrospectively. Results. Both mean CD activity index scores and serum C-reactive protein values were significantly lower after ADA therapy (P < 0.001). In the MUC5AC negative group, all cases exhibited clinical remission (CR) and endoscopic improvement at 52 weeks. In MUC5AC positive groups, loss of MUC5AC expression was detected in cases having CR and endoscopic improvement at 52 weeks, while remnant ectopic MUC5AC expression was observed in those exhibiting no endoscopic improvement and flare up after 52 weeks. Conclusions. ADA leads to CR and endoscopic improvement in biologically naïve CD cases. In addition, ectopic MUC5AC expression may be a predictive marker of flare up and endoscopic improvement in the intestines of CD patients.

Apigenin and Wogonin Regulate Epidermal Growth Factor Receptor Signaling Pathway Involved in MUC5AC Mucin Gene Expression and Production from Cultured Airway Epithelial Cells

Background

We investigated whether wogonin and apigenin significantly affect the epidermal growth factor receptor (EGFR) signaling pathway involved in MUC5AC mucin gene expression, and production from cultured airway epithelial cells; this was based on our previous report that apigenin and wogonin suppressed MUC5AC mucin gene expression and production from human airway epithelial cells.

Methods

Confluent NCI-H292 cells were pretreated with wogonin or apigenin for 15 minutes or 24 hours and then stimulated with epidermal growth factor (EGF) for 24 hours or the indicated periods.

Results

We found that incubation of NCI-H292 cells with wogonin or apigenin inhibited the phosphorylation of EGFR. The downstream signals of EGFR such as phosphorylation of MEK1/2 and ERK1/2 were also inhibited by wogonin or apigenin.

Conclusion

The results suggest that wogonin and apigenin inhibits EGFR signaling pathway, which may explain how they inhibit MUC5AC mucin gene expression and production induced by EGF.