Mucin overproduction in chronic inflammatory lung disease

A comparative study on the protective effects of cuminaldehyde, thymoquinone, and gallic acid against carbon tetrachloride-induced pulmonary and renal toxicity in rats by affecting ROS and NF-κB signaling

CCl4 toxicity is a fatal condition that can cause numerous organ dysfunctions. We evaluated and compared the protective effects of cuminaldehyde (CuA), thymoquinone (TQ), and gallic acid (GA) on CCl4-induced pulmonary and renal toxicity in rats. The impacts of these compounds on CCl4-induced oxidative stress, inflammation, and morphological alterations were examined. The results showed that the compounds under investigation prevented CCl4 from significantly increasing pulmonary and renal lipid peroxidation and NO levels, as well as massively depleting GSH levels and GPX and SOD activities. Moreover, they suppressed the CCl4-induced increase in mucus secretion in the lung and upregulated the gene expression of pulmonary and renal NF-ҡB, iNOS, TNF-α, and COX-2. The heatmap cluster plots showed that GA and TQ had better protective potencies than CuA. The external organ morphology, histopathological results, and chest X-ray analysis confirmed the toxicity of CCl4 and the protective influences of the tested compounds in both the lungs and kidneys of rats. These compounds displayed predicted competitive inhibitory effects on iNOS activity and may block the IL-13α2 receptor, as revealed by molecular docking analysis. Thus, CuA, TQ, and GA, particularly the latter two, are prospective protective compounds against the pulmonary and renal toxicity caused by CCl4.

A Novel Combined Dry Powder Inhaler Comprising Nanosized Ketoprofen-Embedded Mannitol-Coated Microparticles for Pulmonary Inflammations: Development, In Vitro-In Silico Characterization, and Cell Line Evaluation

Pulmonary inflammations such as chronic obstructive pulmonary disease and cystic fibrosis are widespread and can be fatal, especially when they are characterized by abnormal mucus accumulation. Inhaled corticosteroids are commonly used for lung inflammations despite their considerable side effects. By utilizing particle engineering techniques, a combined dry powder inhaler (DPI) comprising nanosized ketoprofen-embedded mannitol-coated microparticles was developed. A nanoembedded microparticle system means a novel advance in pulmonary delivery by enhancing local pulmonary deposition while avoiding clearance mechanisms. Ketoprofen, a poorly water-soluble anti-inflammatory drug, was dispersed in the stabilizer solution and then homogenized by ultraturrax. Following this, a ketoprofen-containing nanosuspension was produced by wet-media milling. Furthermore, co-spray drying was conducted with L-leucine (dispersity enhancer) and mannitol (coating and mucuactive agent). Particle size, morphology, dissolution, permeation, viscosity, in vitro and in silico deposition, cytotoxicity, and anti-inflammatory effect were investigated. The particle size of the ketoprofen-containing nanosuspension was ~230 nm. SEM images of the spray-dried powder displayed wrinkled, coated, and nearly spherical particles with a final size of ~2 µm (nano-in-micro), which is optimal for pulmonary delivery. The mannitol-containing samples decreased the viscosity of 10% mucin solution. The results of the mass median aerodynamic diameter (2.4-4.5 µm), fine particle fraction (56-71%), permeation (five-fold enhancement), and dissolution (80% release in 5 min) confirmed that the system is ideal for local inhalation. All samples showed a significant anti-inflammatory effect and decreased IL-6 on the LPS-treated U937 cell line with low cytotoxicity. Hence, developing an innovative combined DPI comprising ketoprofen and mannitol by employing a nano-in-micro approach is a potential treatment for lung inflammations.

PDZ Peptide of the ZO-1 Protein Significantly Increases UTP-Induced MUC8 Anti-Inflammatory Mucin Overproduction in Human Airway Epithelial Cells

Mucus hyperproduction and hypersecretion are observed often in respiratory diseases. MUC8 is a glycoprotein synthesized by epithelial cells and generally expressed in the respiratory track. However, the physiological mechanism by which extracellular nucleotides induce MUC8 gene expression in human airway epithelial cells is unclear. Here, we show that UTP could induce MUC8 gene expression through P2Y2-PLCβ3-Ca2+ activation. Because the full-length cDNA sequence of MUC8 has not been identified, a specific siRNA-MUC8 was designed based on the partial cDNA sequence of MUC8. siRNA-MUC8 significantly increased TNF-α production and decreased IL-1Ra production, suggesting that MUC8 may downregulate UTP/P2Y2-induced airway inflammation. Interestingly, the PDZ peptide of ZO-1 protein strongly abolished UTP-induced TNF-α production and increased IL-1Ra production and MUC8 gene expression. In addition, the PDZ peptide dramatically increased the levels of UTP-induced ZO proteins and TEER (trans-epithelial electrical resistance). These results show that the anti-inflammatory mucin MUC8 may contribute to homeostasis, and the PDZ peptide can be a novel therapeutic candidate for UTP-induced airway inflammation.

Design and initial testing of a novel disposable oscillating positive expiratory pressure device

BACKGROUND

Oscillating positive expiratory pressure (OPEP) devices play a key role in airway clearance, particularly in patients with cystic fibrosis. These devices, however, have the potential to become reservoirs for pathogenic organisms and require daily, or even more frequent, cleaning. This places a large burden on patients and their carers.

AIMS

The objective of this work was to develop a disposable OPEP device, with comparable mechanical performance to commercial devices, that negates the need for cleaning after use thus reducing microbiological risks.

METHODS

3D printing was used to iterate and develop a prototype disposable device (The University of Limerick OPEP, abbreviated to the UL-OPEP) that was compared with a selection of commercially available devices for mean pressure and oscillation amplitude (cmH2O), as well as oscillation frequency (Hz). All devices were tested using a healthy volunteer at a target expiratory flow of ~ 20 L/min. The target therapeutic range was 10-20 cmH2O at a flow rate of 10-20 L/min as is reported widely in the literature.

RESULTS

The prototype disposable device achieved a mean pressure of 14.82 cmH2O at a mean flow rate of 18.82 L/min, and generated an oscillation frequency of 26 Hz with an amplitude of 1.28 cmH2O. These characteristics compare favourably with existing, more complex, reusable OPEP devices.

CONCLUSIONS

The UL-OPEP device is a small, disposable OPEP device, that generates pressure and oscillation amplitudes for clinically effective airway clearance. The device negates the need for cleaning and disinfecting, removing the risk of devices acting as a potential reservoir for pathogenic organisms while maintaining mucus-clearing benefits.

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.

Exogenous Lipoxin A4 attenuates IL4-induced Mucin Expression in Human Airway Epithelial Cells

Introduction: The proinflammatory cytokine interleukin-4 (IL-4) induces mucus hypersecretion by human airway epithelial cells and the MAP kinase signalling pathway may be important in terms of IL-4-induced MUC5AC gene expression. Lipoxin A₄ (LXA₄) is an arachidonic acid-derived mediator that promotes inflammation by binding to the anti-inflammatory receptors (ALXs) or the formyl-peptide receptor like-1 (FPRL1) protein expressed by airway epithelial cells. Here, we explore the effects of LXA4 on IL-4-induced mucin gene expression in, and secretion from, human airway epithelial cells. Methods: We co-treated cells with IL-4 (20 ng/mL) and LXA₄ (1 nM) and measured the expression levels of mRNAs encoding MUC5AC and 5B via real-time polymerase chain reaction; protein expression levels were determined by Western blotting and immunocytofluorescence. The ability of IL-4 and LXA₄ to suppress protein expression was determined by Western blotting. Results: IL-4 increased MUC5AC and 5B gene and protein expression. LXA₄ suppressed IL-4-induced MUC5AC and 5B gene and protein expression by interacting with the IL4 receptor and mitogen-activated protein kinase (MAPK) pathway, including both phospho-p38 MAPK and phospho-extracellular signal-regulated kinase (phospho-ERK). IL-4 and LXA₄ increased and decreased, respectively, the number of cells that stained with anti-MUC5AC and 5B antibodies. Conclusions: LXA₄ may regulate mucus hypersecretion induced by IL4 in human airway epithelial cells.

Biologics and airway remodeling in severe asthma

Asthma is a chronic inflammatory airway disease resulting in airflow obstruction, which in part can become irreversible to conventional therapies, defining the concept of airway remodeling. The introduction of biologics in severe asthma has led in some patients to the complete normalization of previously considered irreversible airflow obstruction. This highlights the need to distinguish a "fixed" airflow obstruction due to structural changes unresponsive to current therapies, from a "reversible" one as demonstrated by lung function normalization during biological therapies not previously obtained even with high-dose systemic glucocorticoids. The mechanisms by which exposure to environmental factors initiates the inflammatory responses that trigger airway remodeling are still incompletely understood. Alarmins represent epithelial-derived cytokines that initiate immunologic events leading to inflammatory airway remodeling. Biological therapies can improve airflow obstruction by addressing these airway inflammatory changes. In addition, biologics might prevent and possibly even revert "fixed" remodeling due to structural changes. Hence, it appears clinically important to separate the therapeutic effects (early and late) of biologics as a new paradigm to evaluate the effects of these drugs and future treatments on airway remodeling in severe asthma.

Comparative Investigation of Gene Regulatory Processes Underlying Avian Influenza Viruses in Chicken and Duck

Simple Summary

Avian influenza poses a great risk to gallinaceous poultry, while mallard ducks can withstand most virus strains. To date, the mechanisms underlying the susceptibility of chicken and the effective immune response of duck have not been completely understood. In this study, our aim is to investigate the transcriptional gene regulation governing the expression of important avian-influenza-induced genes and to reveal the master regulators stimulating an effective immune response after virus infection in ducks while dysfunctioning in chicken.

Abstract

The avian influenza virus (AIV) mainly affects birds and not only causes animals’ deaths, but also poses a great risk of zoonotically infecting humans. While ducks and wild waterfowl are seen as a natural reservoir for AIVs and can withstand most virus strains, chicken mostly succumb to infection with high pathogenic avian influenza (HPAI). To date, the mechanisms underlying the susceptibility of chicken and the effective immune response of duck have not been completely unraveled. In this study, we investigate the transcriptional gene regulation underlying disease progression in chicken and duck after AIV infection. For this purpose, we use a publicly available RNA-sequencing dataset from chicken and ducks infected with low-pathogenic avian influenza (LPAI) H5N2 and HPAI H5N1 (lung and ileum tissues, 1 and 3 days post-infection). Unlike previous studies, we performed a promoter analysis based on orthologous genes to detect important transcription factors (TFs) and their cooperation, based on which we apply a systems biology approach to identify common and species-specific master regulators. We found master regulators such as EGR1, FOS, and SP1, specifically for chicken and ETS1 and SMAD3/4, specifically for duck, which could be responsible for the duck’s effective and the chicken’s ineffective immune response.

Protective and Anti-Inflammatory Effects of Protegrin-1 on Citrobacter rodentium Intestinal Infection in Mice

Infectious intestinal colitis, manifesting as intestinal inflammation, diarrhea, and epithelial barrier disruption, affects millions of humans worldwide and, without effective treatment, can result in death. In addition to this, the significant rise in antibiotic-resistant bacteria poses an urgent need for alternative anti-infection therapies for the treatment of intestinal disorders. Antimicrobial peptides (AMPs) are potential therapies that have broad-spectrum antimicrobial activity due to their (1) unique mode of action, (2) broad-spectrum antimicrobial activity, and (3) protective role in GI tract maintenance. Protegrin-1 (PG-1) is an AMP of pig origin that was previously shown to reduce the pathological effects of chemically induced digestive tract inflammation (colitis) and to modulate immune responses and tissue repair. This study aimed to extend these findings by investigating the protective effects of PG-1 on pathogen-induced colitis in an infection study over a 10-day experimental period. The oral administration of PG-1 reduced Citrobacter rodentium intestinal infection in mice as evidenced by reduced histopathologic change in the colon, prevention of body weight loss, milder clinical signs of disease, and more effective clearance of bacterial infection relative to challenged phosphate-buffered saline (PBS)-treated mice. Additionally, PG-1 treatment altered the expression of various inflammatory mediators during infection, which may act to resolve inflammation and re-establish intestinal homeostasis. PG-1 administered in its mature form was more effective relative to the pro-form (ProPG-1). To our knowledge, this is the first study demonstrating the protective effects of PG-1 on infectious colitis.

Airway Fibroblast Secretory Products Enhance Cell Migration

Background:

The nasal fibroblast secretome, which includes various cytokines, chemokines, and growth factors, promotes cell migration. Currently, the proteomics of airway fibroblast (AF) conditioned medium (AFCM) are being actively studied.

Objective:

This study was aimed at profiling and identifying the AF secreted proteins that can enhance wound healing of the airway epithelium and predict the potential pathway involved.

Methods:

Airway epithelial cells (AECs) and AFs were isolated from redundant human nasal turbinate and cultured. AFCM was collected by culturing the AFs either with serum-free airway epithelium basal medium (AECM) or with serum-free F12:DMEM (FDCM). For evaluating cell migration, the AECs were supplemented with airway epithelium medium and defined keratinocyte medium (1:1; AEDK; control), or with AEDK supplemented with 20% AECM or 20% FDCM. The mass spectrometry sample was prepared by protein precipitation, followed by gel electrophoresis and in-gel digestion.

Results :

AECM promoted better cell migration compared to the FDCM and the control medium. Bioinformatics analysis identified a total of 121, and 92 proteins from AECM and FDCM, respectively: 109 and 82 were identified as secreted proteins, respectively. STRING® analysis predicted that 23 proteins from the AECM and 16 proteins from the FDCM are involved in wound healing.

Conclusion:

Conditioned medium promotes wound healing by enhancing cell migration, and we successfully identified various secretory proteins in a conditioned medium that play important roles in wound healing.

Targeting TL1A/DR3 Signaling Offers a Therapeutic Advantage to Neutralizing IL13/IL4Rα in Muco-Secretory Fibrotic Disorders

Mucus secretion is an important feature of asthma that highly correlates with morbidity. Current therapies, including administration of mucolytics and anti-inflammatory drugs, show limited effectiveness and durability, underscoring the need for novel effective and longer lasting therapeutic approaches. Here we show that mucus production in the lungs is regulated by the TNF superfamily member 15 (TL1A) acting through the mucus-inducing cytokine IL-13. TL1A induces IL13 expression by innate lymphoid cells leading to mucus production, in addition to promoting airway inflammation and fibrosis. Reciprocally, neutralization of IL13 signaling through its receptor (IL4Rα), completely reverses TL1A-induced mucus secretion, while maintaining airway inflammation and fibrosis. Importance of TL1A is further demonstrated using a preclinical asthma model induced by chronic house dust mite exposure where TL1A neutralization by genetic deletion or antagonistic blockade of its receptor DR3 protected against mucus production and fibrosis. Thus, TL1A presents a promising therapeutic target that out benefits IL13 in reversing mucus production, airway inflammation and fibrosis, cardinal features of severe asthma in humans.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Susceptibility of primary human airway epithelial cells to Bordetella pertussis adenylate cyclase toxin in two- and three-dimensional culture conditions

The human pathogen Bordetella pertussis targets the respiratory epithelium and causes whooping cough. Its virulence factor adenylate cyclase toxin (CyaA) plays an important role in the course of infection. Previous studies on the impact of CyaA on human epithelial cells have been carried out using cell lines derived from the airways or the intestinal tract. Here, we investigated the interaction of CyaA and its enzymatically inactive but fully pore-forming toxoid CyaA-AC^– with primary human airway epithelial cells (hAEC) derived from different anatomical sites (nose and tracheo-bronchial region) in two-dimensional culture conditions. To assess possible differences between the response of primary hAEC and respiratory cell lines directly, we included HBEC3-KT in our studies. In comparative analyses, we studied the impact of both the toxin and the toxoid on cell viability, intracellular cAMP concentration and IL-6 secretion. We found that the selected hAEC, which lack CD11b, were differentially susceptible to both CyaA and CyaA-AC^–. HBEC3-KT appeared not to be suitable for subsequent analyses. Since the nasal epithelium first gets in contact with airborne pathogens, we further studied the effect of CyaA and its toxoid on the innate immunity of three-dimensional tissue models of the human nasal mucosa. The present study reveals first insights in toxin–cell interaction using primary hAEC.

Cigarette smoke preparations, not electronic nicotine delivery system preparations, induce features of lung disease in a 3D lung repeat-dose model

Cigarette smoking is a risk factor for several lung diseases, including chronic obstructive pulmonary disease, cardiovascular disease, and lung cancer. The potential health effects of chronic use of electronic nicotine delivery systems (ENDS) is unclear. This study utilized fully differentiated primary normal human bronchial epithelial (NHBE) cultures in a repeat-dose exposure to evaluate and compare the effect of combustible cigarette and ENDS preparations. We show that 1-h daily exposure of NHBE cultures over a 10-day period to combustible cigarette whole smoke-conditioned media (WS-CM) increased expression of oxidative stress markers, cell proliferation, airway remodeling, and cellular transformation markers and decreased mucociliary function including ion channel function and airway surface liquid. Conversely, aerosol conditioned media (ACM) from ENDS with similar nicotine concentration (equivalent-nicotine units) as WS-CM and nicotine alone had no effect on those parameters. In conclusion, primary NHBE cultures in a repeat-dose exposure system represent a good model to assess the features of lung disease. This study also reveals that cigarette and ENDS preparations differentially elicit several key endpoints, some of which are potential biomarkers for lung cancer or chronic obstructive pulmonary disease (COPD).

Invited review: human air-liquid-interface organotypic airway tissue models derived from primary tracheobronchial epithelial cells-overview and perspectives

The lung is an organ that is directly exposed to the external environment. Given the large surface area and extensive ventilation of the lung, it is prone to exposure to airborne substances, such as pathogens, allergens, chemicals, and particulate matter. Highly elaborate and effective mechanisms have evolved to protect and maintain homeostasis in the lung. Despite these sophisticated defense mechanisms, the respiratory system remains highly susceptible to environmental challenges. Because of the impact of respiratory exposure on human health and disease, there has been considerable interest in developing reliable and predictive in vitro model systems for respiratory toxicology and basic research. Human air-liquid-interface (ALI) organotypic airway tissue models derived from primary tracheobronchial epithelial cells have in vivo–like structure and functions when they are fully differentiated. The presence of the air-facing surface allows conducting in vitro exposures that mimic human respiratory exposures. Exposures can be conducted using particulates, aerosols, gases, vapors generated from volatile and semi-volatile substances, and respiratory pathogens. Toxicity data have been generated using nanomaterials, cigarette smoke, e-cigarette vapors, environmental airborne chemicals, drugs given by inhalation, and respiratory viruses and bacteria. Although toxicity evaluations using human airway ALI models require further standardization and validation, this approach shows promise in supplementing or replacing in vivo animal models for conducting research on respiratory toxicants and pathogens.

The Potential Role and Regulatory Mechanisms of MUC5AC in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is associated with high morbidity and mortality globally. Studies show that airway mucus hypersecretion strongly compromises lung function, leading to frequent hospitalization and mortality, highlighting an urgent need for effective COPD treatments. MUC5AC is known to contribute to severe muco-obstructive lung diseases, worsening COPD pathogenesis. Various pathways are implicated in the aberrant MUC5AC production and secretion MUC5AC. These include signaling pathways associated with mucus-secreting cell differentiation [nuclear factor-κB (NF-κB)and IL-13-STAT6- SAM pointed domain containing E26 transformation-specific transcription factor (SPDEF), as well as epithelial sodium channel (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR)], and signaling pathways related to mucus transport and excretion-ciliary beat frequency (CBF). Various inhibitors of mucus hypersecretion are in clinical use but have had limited benefits against COPD. Thus, novel therapies targeting airway mucus hypersecretion should be developed for effective management of muco-obstructive lung disease. Here, we systematically review the mechanisms and pathogenesis of airway mucus hypersecretion, with emphasis on multi-target and multi-link intervention strategies for the elucidation of novel inhibitors of airway mucus hypersecretion.

In vitro and ex vivo expression of serum amyloid A3 in mouse lung epithelia

BACKGROUND AND PURPOSE

Serum amyloid A (SAA), an acute-phase protein whose level tracks infection and inflammation, is the precursor protein of amyloid A (AA) fibrils that is thought to cause AA amyloidosis in human and animals. SAA protein has several isoforms based on the difference of amino acid sequence, such as SAA1 to SAA4 in mice. AA fibrils are associated with chronic inflammation and are mainly originated from SAA1 produced in the liver. SAA3 reportedly contributes to the innate immune response in epithelia; however, little is known about its role at the lung epithelia. Therefore, we investigated SAA3 expression in the lung epithelium activated by bacterial antigens.

MATERIALS AND METHODS

The expressions of SAA3 and SAA1 mRNA were investigated using quantitative real-time PCR, in vitro using mouse Clara (Club) cells and ex vivo using surgically removed mouse lungs, after their stimulation by using either lipopolysaccharide (LPS), the major outer membranous antigen of gram-negative bacteria, or lipoteichoic acid (LTA), the major outer membranous antigen of gram-positive bacteria. In addition, SAA3 and SAA1/2 proteins in treated lung samples were detected by immunohistochemistry (IHC).

RESULTS

SAA3 mRNA expression increased in cells and lungs treated with either LPS or LTA. SAA3 mRNA was more sensitively expressed in LPS than LTA treatment. In contrast, SAA1 mRNA expression did not increase by either LPS or LTA treatment. Furthermore, SAA3 mRNA expression increased in a dose-dependent manner in cells treated with tumor necrosis factor-alpha. By IHC, SAA3 protein was highly expressed in the luminal side of the bronchial epithelium, while SAA1/2 was not expressed.

CONCLUSION

These results obtained from in vitro and ex vivo experiments suggest that SAA3 plays an important role in the innate immune response to bacterial infection in the lung epithelia.

Effect of Tobacco-specific Nitrosamines on MUC5AC Expression in Human Airway Epithelial Cells

Background and Objectives: Nicotine is oxidized into tobacco-specific nitrosamines (TSNAs; NAB, NAT, NNN, NNAL, NNK) at high temperature and high pressure. TSNAs are associated with airway diseases characterized by mucus hypersecretion as a major pathophysiologic phenomenon. The aim of study is to investigate the effect of TSNAs on mucin overexpression and its molecular mechanism in human airway epithelial cells.Materials and Method: The cytotoxicity of TSNAs was evaluated using EX-Cytox and inverted microscopy. The mRNA and protein levels of MUC5AC and MUC5B were measured using real-time PCR and ELISA.Results: NAB, NNN, NNAL, and NNK did not affect cell viability. NAT did not affect cell viability up to a concentration of 100 μM in human airway epithelial cells. NAT, NNN, NNAL, and NNK significantly induced MUC5AC expression, but not MUC5B expression. NAB did not affect the expression of MUC5AC and MUC5B. Propranolol (a β-adrenergic receptor antagonist) inhibited NAT, NNN, NNAL, and NNK-induced MUC5AC expression, whereas α-bungarotoxin (an α7-nicotinic acetylcholine receptor antagonist) only inhibited NNN- and NNK-induced MUC5AC expression.Conclusion: These results suggested that NAT, NNN, NNAL, and NNK induce MUC5AC expression through β-adrenergic receptor and/or α7-nicotinic acetylcholine receptor in human airway epithelial cells, which may be involved in mucus hypersecretion in inflammatory airway diseases.

Semantic characterization of adverse outcome pathways

This study was undertaken to systematically assess the utilities and performance of ontology-based semantic analysis in adverse outcome pathway (AOP) research. With an increasing number of AOPs developed by scientific domain experts to organize toxicity information and facilitate chemical risk assessment, there is a pressing need for objective approaches to evaluate the biological coherence and quality of these AOPs. Powered by ontologies covering a wide range of biological domains, abundant phenotypic data annotated ontologically, and some sophisticated knowledge computing tools, semantic analysis has great potential in this area of application. With the events in the AOP-Wiki first annotated into logical definitions and then grouped into phenotypic profiles by individual AOPs, the coherence and quality of AOPs were assessed at several levels: paired key event relationships (KER), all possible event pair combinations within AOPs, and the phenotypic profiles of AOPs, genes, biological pathways, human diseases, and selected chemicals. The semantic similarities were assessed at all these levels based on a unified cross-species vertebrate phenotype ontology encompassing the logical definitions of AOP events as well as many other domain ontologies. A substantial number of KERs and AOPs in the AOP-Wiki were found to be semantically coherent. These same coherent AOPs also mapped to many more genes, pathways, and diseases biologically aligned with the intended chain of events therein leading to their respective adverse outcomes. Significantly, these findings imply that semantic analysis should also have utilities in developing future AOPs by selecting candidate events from either the existing AOP-Wiki events or a broader collection of ontology terms semantically similar to the molecular initiating events or adverse outcomes of interest. In addition, semantic analysis enabled AOP networks to be constructed at the level of phenotypic profiles based on similarities, complementing those based on event sharing by bringing genes, pathways, diseases, and chemicals into the networks too-thus greatly expanding the biological scope and our understanding of AOPs.

Exposure to mold proteases stimulates mucin production in airway epithelial cells through Ras/Raf1/ERK signal pathway

Environmental mold (fungus) exposure poses a significant threat to public health by causing illnesses ranging from invasive fungal diseases in immune compromised individuals to allergic hypertensive diseases such as asthma and asthma exacerbation in otherwise healthy people. However, the molecular pathogenesis has not been completely understood, and treatment options are limited. Due to its thermo-tolerance to the normal human body temperature, Aspergillus. fumigatus (A.fumigatus) is one of the most important human pathogens to cause different lung fungal diseases including fungal asthma. Airway obstruction and hyperresponsiveness caused by mucus overproduction are the hallmarks of many A.fumigatus induced lung diseases. To understand the underlying molecular mechanism, we have utilized a well-established A.fumigatus extracts (AFE) model to elucidate downstream signal pathways that mediate A.fumigatus induced mucin production in airway epithelial cells. AFE was found to stimulate time- and dose-dependent increase of major airway mucin gene expression (MUC5AC and MUC5B) partly via the elevation of their promoter activities. We also demonstrated that EGFR was required but not sufficient for AFE-induced mucin expression, filling the paradoxical gap from a previous study using the same model. Furthermore, we showed that fungal proteases in AFE were responsible for mucin induction by activating a Ras/Raf1/ERK signaling pathway. Ca2+ signaling, but ROS, both of which were stimulated by fungal proteases, was an indispensable determinant for ERK activation and mucin induction. The discovery of this novel pathway likely contributes to our understanding of the pathogenesis of fungal sensitization in allergic diseases such as fungal asthma.

Development of a Chemical Toolset for Studying the Paralog-Specific Function of IRE1

The dual kinase endoribonuclease IRE1 is a master regulator of cell fate decisions in cells experiencing endoplasmic reticulum (ER) stress. In mammalian cells, there are two paralogs of IRE1: IRE1α and IRE1β. While IRE1α has been extensively studied, much less is understood about IRE1β and its role in signaling. In addition, whether the regulation of IRE1β's enzymatic activities varies compared to IRE1α is not known. Here, we show that the RNase domain of IRE1β is enzymatically active and capable of cleaving an XBP1 RNA mini-substrate in vitro. Using ATP-competitive inhibitors, we find that, like IRE1α, there is an allosteric relationship between the kinase and RNase domains of IRE1β. This allowed us to develop a novel toolset of both paralog specific and dual-IRE1α/β kinase inhibitors that attenuate RNase activity (KIRAs). Using sequence alignments of IRE1α and IRE1β, we propose a model for paralog-selective inhibition through interactions with nonconserved residues that differentiate the ATP-binding pockets of IRE1α and IRE1β.

Glycosylation changes in inflammatory diseases

Glycosylation is one of the most important modifications of proteins and lipids, and cell surface glycoconjugates are thought to play important roles in a variety of biological functions including cell-cell and cell-substrate interactions, bacterial adhesion, cell immunogenicity and cell signaling. Alterations of glycosylation are observed in a number of inflammatory diseases. Pro-inflammatory cytokines have been shown to modulate cell surface glycosylation by regulating the expression of glycosyltransferases and sulfotransferases involved in the biosynthesis of glycan chains, inducing the expression of specific carbohydrate antigens at the cell surface that can be recognized by different types of lectins or by bacterial adhesins, contributing to the development of diseases. Glycosylation can also regulate biological functions of immune cells by recruiting leukocytes to inflammation sites with pro- or anti-inflammatory effects. Cell surface proteoglycans provide a large panel of binding sites for many mediators of inflammation, and regulate their bio-availability and functions. In this review, we summarize the current knowledge of the glycosylation changes occurring in mucin type O-linked glycans, glycosaminoglycans, as well as in glycosphingolipids, with a particular focus on cystic fibrosis and neurodegenerative diseases, and their consequences on cell interactions and disease progression.

Nanoparticle diffusion in spontaneously expectorated sputum as a biophysical tool to probe disease severity in COPD

Perturbations in airway mucus properties contribute to lung function decline in patients with chronic obstructive pulmonary disease (COPD). While alterations in bulk mucus rheology have been widely explored, microscopic mucus properties that directly impact on the dynamics of microorganisms and immune cells in the COPD lungs are yet to be investigated.We hypothesised that a tightened mesh structure of spontaneously expectorated mucus (i.e. sputum) would contribute to increased COPD disease severity. Here, we investigated whether the mesh size of COPD sputum, quantified by muco-inert nanoparticle (MIP) diffusion, correlated with sputum composition and lung function measurements.The microstructure of COPD sputum was assessed based on the mean squared displacement (MSD) of variously sized MIPs measured by multiple particle tracking. MSD values were correlated with sputum composition and spirometry. In total, 33 samples collected from COPD or non-COPD individuals were analysed.We found that 100 nm MIPs differentiated microstructural features of COPD sputum. The mobility of MIPs was more hindered in sputum samples from patients with severe COPD, suggesting a tighter mucus mesh size. Specifically, MSD values inversely correlated with lung function.These findings suggest that sputum microstructure may serve as a novel risk factor for COPD progression and severity.

Assessing the respiratory toxicity of dihydroxyacetone using an in vitro human airway epithelial tissue model

Dihydroxyacetone (DHA) is an approved color additive used in sunless tanning lotions. Recently, there has been an increased use of DHA in sunless tanning booths in a manner that could result in its inhalation during application. In the present study, we have evaluated the potential for DHA causing toxicity via inhalation using a human air-liquid-interface (ALI) in vitro airway epithelial tissue model. ALI airway models have a close structural and functional resemblance to the in vivo airway epithelium, and thus data generated in these models may have relevance for predicting human responses. To simulate in vivo exposure conditions, we employed a method for liquid aerosol generation that mimics the physical form of inhaled chemicals and used doses of DHA and an exposure frequency reflecting human respiratory exposures during tanning sessions. Compared to the vehicle control, cilia beating frequency (CBF) and MUC5AC secretion were significantly decreased after each exposure. However, time-course studies indicated that both CBF and MUC5AC secretion returned to normal levels within 3 days after the treatment. Matrix metalloproteinase (MMP) release, on the other hand, was decreased 24 h after the first exposure and its level returned to baseline after 5 exposures. No significant morphological changes occurred in the DHA-treated cultures after 5 weekly exposures. Our findings indicate that DHA, at concentrations likely to be experienced by humans, has transient toxic effects on human airway ALI cultures.

Evaluating Mode of Action of Acrolein Toxicity in an In Vitro Human Airway Tissue Model

Acrolein is a reactive unsaturated aldehyde and is found at high concentrations in both mainstream and side-stream tobacco smoke. Exposure to acrolein via cigarette smoking has been associated with acute lung injury, chronic obstructive pulmonary diseases (COPDs), and asthma. In this study, we developed an in vitro treatment strategy that resembles the inhalation exposure to acrolein experienced by smokers and systematically examined the adverse respiratory effects induced by the noncytotoxic doses of acrolein in a human airway epithelial tissue model. A single 10-min exposure to buffered saline containing acrolein significantly induced oxidative stress and inflammatory responses, with changes in protein oxidation and GSH depletion occurring immediately after the treatment whereas responses in inflammation requiring a manifestation time of at least 24 h. Repeated exposure to acrolein for 10 consecutive days resulted in structural and functional changes that recapitulate the pathological lesions of COPD, including alterations in the beating frequency and structures of ciliated cells, inhibition of mucin expression and secretion apparatus, and development of squamous differentiation. Although some of the early responses caused by acrolein exposure were reversible after a 10-day recovery, perturbations in the functions and structures of the air-liquid-interface (ALI) cultures, such as mucin production, cilia structures, and morphological changes, failed to fully recover over the observation period. Taken together, these findings are consistent with its mode of action that oxidative stress and inflammation have fundamental roles in acrolein-induced tissue remodeling. Furthermore, these data demonstrate the usefulness of analytical methods and testing strategy for recapitulating the key events in acrolein toxicity using an in vitro model.

Goblet cells: multifaceted players in immunity at mucosal surfaces

Goblet cells (GCs) are specialized epithelial cells that line multiple mucosal surfaces and have a well-appreciated role in barrier maintenance through the secretion of mucus. Moreover, GCs secrete anti-microbial proteins, chemokines, and cytokines demonstrating functions in innate immunity beyond barrier maintenance. Recently it was appreciated that GCs can form goblet cell-associated antigen passages (GAPs) and deliver luminal substances to underlying lamina propria (LP) antigen-presenting cells (APCs) in a manner capable of inducing adaptive immune responses. GCs at other mucosal surfaces share characteristics with the GAP forming intestinal GCs, suggesting that GAP formation may not be restricted to the gut, and that GCs may perform this gatekeeper function at other mucosal surfaces. Here we review observations of how GCs contribute to immunity at mucosal surfaces through barrier maintenance, the delivery of luminal substances to APCs, interactions with APCs, and secretion of factors modulating immune responses.

Inhibition of mucin secretion via glucocorticoid-induced regulation of calcium-related proteins in mouse lung

Calcium is important for physiological functioning in many tissues and is essential in mucus secretion and muscle contraction. Intracellular concentrations of calcium are regulated by calcium-related proteins, such as transient receptor potential cation channel subfamily V member 4 (TRPV 4), TRPV6, Calbindin-D9k (CaBP-9k), sodium-calcium exchanger (NCX1), and plasma membrane Ca2+ ATPase 1 (PMCA1). In this study, the relationship between secretion of pulmonary mucus and calcium regulation was investigated. To confirm the effect of steroid hormones, immature mice were injected with estrogen (E2) or progesterone (P4), and mature mice were injected with dexamethasone (DEX). Subsequently, the location and expression of TRPV4, TRPV6, CaBP-9k, NCX1, and PMCA1 in lung tissue were examined. Periodic acid-Schiff staining was performed to investigate functional aspects of the protein expression. There were no significant differences in calcium-related gene expression in E2- and P4-treated mice, but TRPV4, NCX1, and PMCA1 were increased in DEX-treated mice and were recovered by RU486 treatment. DEX induces the expression of calcium-related proteins through the glucocorticoid receptor-mediated pathway and may involve decreased mucin secretion in the bronchiole. TRPV4, TRPV6, CaBP-9k, NCX1, and PMCA1 were specifically expressed in Clara and alveolar type 2 cells of mouse lung. CC10, a marker of Clara cells, was decreased by DEX. In addition, mucin secretion, which is a functional aspect of this cell, was also decreased by DEX treatment. Control of calcium-related gene expression may affect the control of mucus secretion in the lung. Such a control mechanism can form the basis of studies into diseases such as inflammation attributable to mucus secretion abnormalities, coughing, and respiratory disorders and distress.

Targeting the 15-keto-PGE2-PTGR2 axis modulates systemic inflammation and survival in experimental sepsis

Sepsis is a systemic inflammation accompanied by multi-organ dysfunction due to microbial infection. Prostaglandins and their metabolites have long been studied for their importance in regulating the innate immune response. 15-keto-PGE2 (15k-PGE₂) is a prostaglandin E2 (PGE₂) metabolite, whose further processing is catalyzed by prostaglandin reductase 2 (PTGR2). We showed disruption of the Ptgr2 gene in mice improves the survival rate under both LPS- and cecum ligation/puncture (CLP)-induced experimental sepsis. Knockdown of PTGR2 showed significant accumulation of intracellular 15k-PGE₂ in activated macrophages. Both PTGR2 knockdown and exogenous treatment with 15k-PGE₂ resulted in reduced pro-inflammatory cytokines production in LPS-stimulated RAW264.7 cells or bone marrow-derived macrophages (BMDM). The same treatment in RAW264.7 and BMDM also led to increased levels of the anti-oxidative transcription factor, Nuclear factor (erythroid-2) related factor-2 (NRF2), augmented anti-oxidant response element (ARE)-mediated reporter activity and upregulated expression of the corresponding anti-oxidant genes. 15k-PGE₂ further demonstrated modification to Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of Nrf2, at cysteine 288 (Cys288) site post-translationally. Finally, 15k-PGE₂-treated mice were found to be more resistant to experimental sepsis. Taken together, our study affirms the significance of PTGR2 and 15k-PGE₂ in mitigating inflammatory responses and suggests a novel anti-oxidative and anti-inflammatory therapy for sepsis through targeting PTGR2 and administering15k-PGE₂.

Polymorphisms of TGFB1, TLE4 and MUC22 are associated with childhood asthma in Chinese population

OBJECTIVE

To investigate whether the genetic variants of TGFB1, TLE4, MUC22 and IKZF3 are associated with the development of asthma in Chinese children.

METHODS

572 adolescent asthma patients and 590 age-matched healthy controls were included in this study. A total of four SNPs were genotyped, including rs2241715 of TGFB1, rs2378383 of TLE4, rs2523924 of MUC22, and rs907092 of IKZF3. Allele frequencies of the patients and the control group were compared by the Chi-square test. The Student t test was used to analyse the relationship between genotypes and clinical feature of the patients.

RESULTS

Patients were found to have significantly different frequencies of allele A of rs2241715, allele G of rs2378383 and allele A of rs2523924 as compared with the controls (40.4% vs. 45.9%, p=0.01 for rs2241715; 17.2% vs. 13.4%, p=0.01 for rs2378383; 15.3% vs. 11.9%, p=0.02 for rs2523924). For patients with severe asthma, those with genotype AA/AG of rs2241715 had remarkably higher FEV1% as compared with those with genotype GG (59.1±4.3% vs. 55.4±3.7%, p<0.001). Moreover, those with genotype GG/GA of rs2378383 had remarkably lower FEV1% as compared with those with genotype AA (54.6±2.9% vs. 58.6±4.1%, p<0.001).

CONCLUSIONS

Genes TGFB1, TLE4 and MUC22 are associated with the risk of childhood asthma in Chinese population. Our results associating TGFB1 and TLE4 with clinical features of asthma suggest potential application of these parameters in the management of asthma children.

Attenuation of MUC4 potentiates the anticancer activity of auranofin via regulation of the Her2/Akt/FOXO3 pathway in ovarian cancer cells

Previously, we reported that auranofin induces apoptosis in SKOV3 cells via regulation of the IKKβ/FOXO3 pathway. In the present study, we reveal that the anticancer activity of auranofin in SKOV3 cells could be enhanced by the attenuation of MUC4 through the regulation of the Her2/Akt/FOXO3 pathway. Compared to the control-siRNA, siRNA transfection against MUC4 into SKOV3 cells accelerated the protein degradation of Her2. Under the same conditions, the expression level of phosphorylated Akt was also downregulated leading to an increase of FOXO3 in the nucleus. Notably, auranofin treatment in SKOV3 cells also resulted in the downregulation of the expression levels of both Her2 and phosphorylated Akt. Thus, Her2 was identified as the common molecular target protein by siRNA transfection against MUC4. Western blot analysis of total and nuclear fraction lysates from SKOV3 cells revealed that attenuation of MUC4 combined with auranofin treatment in SKOV3 cells synergistically activated FOXO3 translocation from the cytoplasm to the nucleus through the regulation of the Her2/Akt/FOXO3 pathway. Attenuation of MUC4 by siRNA transfection potentiated the antitumor effect of auranofin which was examined by performing in vitro assays such as WST-1, cell counting, colony formation, TUNEL and Annexin V staining. In addition, western blot analysis of the apoptosis‑related proteins such as PARP1, caspase-3, Bim extra large (EL), Bax and Bcl2 revealed that the attenuation of MUC4 by siRNA transfection potentiates the pro-apoptotic activity of auranofin in SKOV3 cells. Collectively, auranofin could regulate the Her2/Akt/FOXO3 signaling pathway in SKOV3 cells and be used as a potential antitumor agent considering the expression of MUC4 in ovarian cancer patients.

Enrichment of in vivo transcription data from dietary intervention studies with in vitro data provides improved insight into gene regulation mechanisms in the intestinal mucosa

Background

Gene expression profiles of intestinal mucosa of chickens and pigs fed over long-term periods (days/weeks) with a diet rich in rye and a diet supplemented with zinc, respectively, or of chickens after a one-day amoxicillin treatment of chickens, were recorded recently. Such dietary interventions are frequently used to modulate animal performance or therapeutically for monogastric livestock. In this study, changes in gene expression induced by these three interventions in cultured “Intestinal Porcine Epithelial Cells” (IPEC-J2) recorded after a short-term period of 2 and 6 hours, were compared to the in vivo gene expression profiles in order to evaluate the capability of this in vitro bioassay in predicting in vivo responses.

Methods

Lists of response genes were analysed with bioinformatics programs to identify common biological pathways induced in vivo as well as in vitro. Furthermore, overlapping genes and pathways were evaluated for possible involvement in the biological processes induced in vivo by datamining and consulting literature.

Results

For all three interventions, only a limited number of identical genes and a few common biological processes/pathways were found to be affected by the respective interventions. However, several enterocyte-specific regulatory and secreted effector proteins that responded in vitro could be related to processes regulated in vivo, i.e. processes related to mineral absorption, (epithelial) cell adherence and tight junction formation for zinc, microtubule and cytoskeleton integrity for amoxicillin, and cell-cycle progression and mucus production for rye.

Conclusions

Short-term gene expression responses to dietary interventions as measured in the in vitro bioassay have a low predictability for long-term responses as measured in the intestinal mucosa in vivo. The short-term responses of a set regulatory and effector genes, as measured in this bioassay, however, provided additional insight into how specific processes in piglets and broilers may be modulated by “early” signalling molecules produced by enterocytes. The relevance of this set of regulatory/effector genes and cognate biological processes for zinc deficiency and supplementation, gluten allergy (rye), and amoxicillin administration in humans is discussed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12263-017-0559-1) contains supplementary material, which is available to authorized users.

Lyn regulates mucus secretion and MUC5AC via the STAT6 signaling pathway during allergic airway inflammation

Hypersecretion of mucus is an important component of airway remodeling and contributes to the mucus plugs and airflow obstruction associated with severe asthma phenotypes. Lyn has been shown to down-regulate allergen-induced airway inflammation. However, the role of Lyn in mucin gene expression remains unresolved. In this study, we first demonstrate that Lyn overexpression decreased the mucus hypersecretion and levels of the muc5ac transcript in mice exposed to ovalbumin (OVA). Lyn overexpression also decreased the infiltration of inflammatory cells and the levels of IL-13 and IL-4 in OVA-challenged airways. Whereas Lyn knockdown increased the IL-4 or IL-13-induced MUC5AC transcript and protein levels in the human bronchial epithelial cell line, 16HBE, Lyn overexpression decreased IL-4- or IL-13-induced MUC5AC transcript and protein levels. Overexpression of Lyn also decreased the expression and phosphorylation of STAT6 in OVA-exposed mice, whereas Lyn knockdown increased STAT6 and MUC5AC levels in 16HBE cells. Finally, chromatin immunoprecipitation analysis confirmed that Lyn overexpression decreased the binding of STAT6 to the promoter region of Muc5ac in mice exposed to OVA. Collectively, these findings demonstrated that Lyn overexpression ameliorated airway mucus hypersecretion by down-regulating STAT6 and its binding to the MUC5AC promoter.

Role of Cytokine-Induced Glycosylation Changes in Regulating Cell Interactions and Cell Signaling in Inflammatory Diseases and Cancer

Glycosylation is one of the most important modifications of proteins and lipids, and cell surface glycoconjugates are thought to play important roles in a variety of biological functions including cell-cell and cell-substrate interactions, bacterial adhesion, cell immunogenicity and cell signaling. Alterations of glycosylation are observed in number of diseases such as cancer and chronic inflammation. In that context, pro-inflammatory cytokines have been shown to modulate cell surface glycosylation by regulating the expression of glycosyltransferases involved in the biosynthesis of carbohydrate chains. These changes in cell surface glycosylation are also known to regulate cell signaling and could contribute to disease pathogenesis. This review summarizes our current knowledge of the glycosylation changes induced by pro-inflammatory cytokines, with a particular focus on cancer and cystic fibrosis, and their consequences on cell interactions and signaling.

Advances and Challenges in Recapitulating Human Pulmonary Systems: At the Cusp of Biology and Materials

The aim of this review is to provide an overview of physiologically relevant microengineered lung-on-a-chip (LoC) platforms for a variety of different biomedical applications with emphasis on drug screening. First, a brief outline of lung anatomy and physiology is presented followed by discussion of the lung parenchyma and its extracellular matrix. Next, we point out the technical challenges in recapitulating the complexity of lung in conventional static two-dimensional microenvironments and the need for alternate lung platforms. The importance of scaling laws is also emphasized in designing these in vitro microengineered lung platforms. The review then discusses current LoC platforms that have been used for testing the efficacy of drugs or as model systems for investigating disorders of the lung parenchyma. Finally, the design parameters in developing an ideal physiologically relevant LoC platform are presented. As this emerging field of organ-on-a-chip can serve an alternative platform for animal testing of drugs or modeling human diseases in vitro, it has significant potential to impact the future of pharmaceutical research.

Human Respiratory Syncytial Virus: Role of Innate Immunity in Clearance and Disease Progression

Human respiratory syncytial virus (HRSV) infections have worldwide records. The virus is responsible for bronchiolitis, pneumonia, and asthma in humans of different age groups. Premature infants, young children, and immunocompromised individuals are prone to severe HRSV infection that may lead to death. Based on worldwide estimations, millions of cases were reported in both developed and developing countries. In fact, HRSV symptoms develop mainly as a result of host immune response. Due to inability to establish long lasting adaptive immunity, HRSV infection is recurrent and hence impairs vaccine development. Once HRSV attached to the airway epithelia, interaction with the host innate immune components starts. HRSV interaction with pulmonary innate defenses is crucial in determining the disease outcome. Infection of alveolar epithelial cells triggers a cascade of events that lead to recruitment and activation of leukocyte populations. HRSV clearance is mediated by a number of innate leukocytes, including macrophages, natural killer cells, eosinophils, dendritic cells, and neutrophils. Regulation of these cells is mediated by cytokines, chemokines, and other immune mediators. Although the innate immune system helps to clear HRSV infection, it participates in disease progression such as bronchiolitis and asthma. Resolving the mechanisms by which HRSV induces pathogenesis, different possible interactions between the virus and immune components, and immune cells interplay are essential for developing new effective vaccines. Therefore, the current review focuses on how the pulmonary innate defenses mediate HRSV clearance and to what extent they participate in disease progression. In addition, immune responses associated with HRSV vaccines will be discussed.

Secretory leukocyte protease inhibitor (SLPI), a multifunctional protein in the host defense response

Secretory leukocyte protease inhibitor (SLPI), a ∼12kDa nonglycosylated cationic protein, is emerging as an important regulator of innate and adaptive immunity and as a component of tissue regenerative programs. First described as an inhibitor of serine proteases such as neutrophil elastase, this protein is increasingly recognized as a molecule that benefits the host via its anti-proteolytic, anti-microbial and immunomodulatory activities. Here, we discuss the diverse functions of SLPI. Moreover, we review several novel layers of SLPI-mediated control that protect the host from excessive/dysregulated inflammation typical of infectious, allergic and autoinflammatory diseases and that support healing responses through affecting cell proliferation, differentiation and apoptosis.

Cryptococcus neoformans Infection in Mice Lacking Type I Interferon Signaling Leads to Increased Fungal Clearance and IL-4-Dependent Mucin Production in the Lungs

Type I interferons (IFNs) are secreted by many cell types upon stimulation via pattern recognition receptors and bind to IFN-α/β receptor (IFNAR), which is composed of IFNAR1 and IFNAR2. Although type I IFNs are well known as anti-viral cytokines, limited information is available on their role during fungal infection. In the present study, we addressed this issue by examining the effect of IFNAR1 defects on the host defense response to Cryptococcus neoformans. In IFNAR1KO mice, the number of live colonies was lower and the host immune response mediated not only by Th1 but also by Th2 and Th17-related cytokines was more accelerated in the infected lungs than in WT mice. In addition, mucin production by bronchoepithelial cells and expression of MUC5AC, a major core protein of mucin in the lungs, were significantly higher in IFNAR1KO mice than in WT mice. This increase in mucin and MUC5AC production was significantly inhibited by treatment with neutralizing anti-IL-4 mAb. In contrast, administration of recombinant IFN-αA/D significantly suppressed the production of IL-4, but not of IFN-γ and IL-17A, in the lungs of WT mice after cryptococcal infection. These results indicate that defects of IFNAR1 led to improved clearance of infection with C. neoformans and enhanced synthesis of IFN-γ and the IL-4-dependent production of mucin. They also suggest that type I IFNs may be involved in the negative regulation of early host defense to this infection.

Lawsonia intracellularis infection of intestinal crypt cells is associated with specific depletion of secreted MUC2 in goblet cells

The expression patterns of secreted (MUC2 and MUC5AC) and membrane-tethered (MUC1, MUC4, MUC12 and MUC13) mucins were monitored in healthy pigs and pigs challenged orally with Lawsonia intracellularis. These results showed that the regulation of mucin gene expression is distinctive along the GI tract of the healthy pig, and may reflect an association between the function of the mucin subtypes and different physiological demands at various sites. We identified a specific depletion of secreted MUC2 from goblet cells in infected pigs that correlated with the increased level of intracellular bacteria in crypt cells. We concluded that L. intracellularis may influence MUC2 production, thereby altering the mucus barrier and enabling cellular invasion.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

Mucins are major glycoprotein components of the mucus that coats the surfaces of cells lining the respiratory, digestive, gastrointestinal and urogenital tracts. They function to protect epithelial cells from infection, dehydration and physical or chemical injury, as well as to aid the passage of materials through a tract i.e., lubrication. They are also implicated in the pathogenesis of benign and malignant diseases of secretory epithelial cells. In Human there are two types of mucins, membrane-bound and secreted that are originated from mucous producing goblet cells localized in the epithelial cell layer or in mucous producing glands and encoded by MUC gene. Mucins belong to a heterogeneous family of high molecular weight proteins composed of a long peptidic chain with a large number of tandem repeats that form the so-called mucin domain. The molecular weight is generally high, ranging between 0.2 and 10 million Dalton and all mucins contain one or more domains which are highly glycosylated. The size and number of repeats vary between mucins and the genetic polymorphism represents number of repeats (VNTR polymorphisms), which means the size of individual mucins can differ substantially between individuals which can be used as markers. In human it is only MUC1 and MUC7 that have mucin domains with less than 40% serine and threonine which in turn could reduce number of PTS domains. Mucins can be considered as powerful two-edged sword, as its normal function protects from unwanted substances and organisms at an arm's length while, malfunction of mucus may be an important factor in human diseases. In this review we have unearthed the current status of different mucin proteins in understanding its role and function in various non-communicable diseases in human with special reference to its organ specific locations. The findings described in this review may be of direct relevance to the major research area in biomedicine with reference to mucin and mucin associated diseases.

Differential mucin expression by respiratory syncytial virus and human metapneumovirus infection in human epithelial cells

Mucins (MUC) constitute an important component of the inflammatory and innate immune response. However, the expression of these molecules by respiratory viral infections is still largely unknown. Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are two close-related paramyxoviruses that can cause severe low respiratory tract disease in infants and young children worldwide. Currently, there is not vaccine available for neither virus. In this work, we explored the differential expression of MUC by RSV and hMPV in human epithelial cells. Our data indicate that the MUC expression by RSV and hMPV differs significantly, as we observed a stronger induction of MUC8, MUC15, MUC20, MUC21, and MUC22 by RSV infection while the expression of MUC1, MUC2, and MUC5B was dominated by the infection with hMPV. These results may contribute to the different immune response induced by these two respiratory viruses.

Anti-asthmatic activities of an ethanol extract of Aster yomena in an ovalbumin-induced murine asthma model

Aster yomena is used in traditional remedies to treat cough, asthma and insect bites; however, its therapeutic mechanism is not completely understood. To elucidate the anti-asthmatic effect of A. yomena, we investigated the anti-asthmatic characteristics of an alcohol extract of A. yomena in an ovalbumin (OVA)-induced murine asthma model. In this study, we showed that A. yomena extract inhibited the overall pathophysiological features of asthma by suppressing Th2 responses and enzymes associated with the production of inflammatory mediators. This suppression resulted in decreased Th2 type cytokines and eosinophils in the bronchoalveolar lavage fluid and OVA-specific IgE in serum. Additionally, A. yomena extract significantly decreased airway hyperresponsiveness and abrogated the histopathological changes in the lungs, which reached normal levels in the OVA-challenged mice treated with A. yomena extract. These findings suggest that A. yomena could be a promising natural agent for treating bronchial asthma in humans.

Altered expression of transmembrane mucins, MUC1 and MUC4, in bladder cancer: pathological implications in diagnosis

PURPOSE

Radical changes in both expression and glycosylation pattern of transmembrane mucins have been observed in various malignancies. We and others have shown that MUC1 and MUC4, two transmembrane mucins, play a sentinel role in cell signaling events that drive several epithelial malignancies. In the present study, we investigated the expression profile of MUC1 and MUC4 in the non-neoplastic bladder urothelium, in various malignant neoplasms of bladder and in bladder carcinoma cell lines.

MATERIAL AND METHODS

Immunohistochemistry was performed on tissue sections from the urinary bladder biopsies, resection samples and tissue microarrays (TMAs) with monoclonal antibodies specific for MUC1 and MUC4. We also investigated their expression in bladder carcinoma cell lines by RT-PCR and immunoblotting.

RESULTS

MUC1 is expressed on the apical surface or in umbrella cells of the normal non-neoplastic bladder urothelium. Strong expression of MUC1 was also observed in urothelial carcinoma (UC). MUC1 staining increased from normal urothelium (n = 27, 0.35±0.12) to urothelial carcinoma (UC, n = 323, H-score, 2.4±0.22, p≤0.0001). In contrast to MUC1, MUC4 was expressed in all the layers of non-neoplastic bladder urothelium (n = 14, 2.5±0.28), both in the cell membrane and cytoplasm. In comparison to non-neoplastic urothelium, the loss of MUC4 expression was observed during urothelial carcinoma (n = 211, 0.56±0.06). However, re-expression of MUC4 was observed in a subset of metastatic cases of urothelial carcinoma (mean H-score 0.734±0.9).

CONCLUSION

The expression of MUC1 is increased while that of MUC4 decreased in UC compared to the normal non-neoplastic urothelium. Expression of both MUC1 and MUC4, however, are significantly higher in urothelial carcinoma metastatic cases compared to localized UC. These results suggest differential expression of MUC1 and MUC4 during development and progression of bladder carcinoma.

The epithelium in idiopathic pulmonary fibrosis: breaking the barrier

Idiopathic pulmonary fibrosis is a progressive disease of unknown etiology characterized by a dysregulated wound healing response that leads to fatal accumulation of fibroblasts and extracellular matrix (ECM) in the lung, which compromises tissue architecture and lung function capacity. Injury to type II alveolar epithelial cells is thought to be the key event for the initiation of the disease, and so far both genetic factors, such as mutations in telomerase and MUC5B genes as well as environmental components, like cigarette smoking, exposure to asbestos and viral infections have been implicated as potential initiating triggers. The injured epithelium then enters a state of senescence-associated secretory phenotype whereby it produces both pro-inflammatory and pro-fibrotic factors that contribute to the wound healing process in the lung. Immune cells, like macrophages and neutrophils as well as activated myofibroblasts then perpetuate this cascade of epithelial cell apoptosis and proliferation by release of pro-fibrotic transforming growth factor beta and continuous deposition of ECM stiffens the basement membrane, altogether having a deleterious impact on epithelial cell function. In this review, we describe the role of the epithelium as both a physical and immunological barrier between environment and self in the homeostatic versus diseased lung and explore the potential mechanisms of epithelial cell injury and the impact of loss of epithelial cell permeability and function on cytokine production, inflammation, and myofibroblast activation in the fibrotic lung.

Bacteria in the vaginal microbiome alter the innate immune response and barrier properties of the human vaginal epithelia in a species-specific manner

BACKGROUND

Bacterial vaginosis increases the susceptibility to sexually transmitted infections and negatively affects women's reproductive health.

METHODS

To investigate host-vaginal microbiota interactions and the impact on immune barrier function, we colonized 3-dimensional (3-D) human vaginal epithelial cells with 2 predominant species of vaginal microbiota (Lactobacillus iners and Lactobacillus crispatus) or 2 prevalent bacteria associated with bacterial vaginosis (Atopobium vaginae and Prevotella bivia).

RESULTS

Colonization of 3-D vaginal epithelial cell aggregates with vaginal microbiota was observed with direct attachment to host cell surface with no cytotoxicity. A. vaginae infection yielded increased expression membrane-associated mucins and evoked a robust proinflammatory, immune response in 3-D vaginal epithelial cells (ie, expression of CCL20, hBD-2, interleukin 1β, interleukin 6, interleukin 8, and tumor necrosis factor α) that can negatively affect barrier function. However, P. bivia and L. crispatus did not significantly upregulate pattern-recognition receptor-signaling, mucin expression, antimicrobial peptides/defensins, or proinflammatory cytokines in 3-D vaginal epithelial cell aggregates. Notably, L. iners induced pattern-recognition receptor-signaling activity, but no change was observed in mucin expression or secretion of interleukin 6 and interleukin 8.

CONCLUSIONS

We identified unique species-specific immune signatures from vaginal epithelial cells elicited by colonization with commensal and bacterial vaginosis-associated bacteria. A. vaginae elicited a signature that is consistent with significant disruption of immune barrier properties, potentially resulting in enhanced susceptibility to sexually transmitted infections during bacterial vaginosis.

A decoy oligonucleotide to NF-κB delivered through inhalable particles prevents LPS-induced rat airway inflammation

The inflammatory process plays a crucial role in the onset and progression of several lung pathologies, including cystic fibrosis (CF), and the involvement of NF-κB is widely recognized. The specific inhibition of NF-κB by decoy oligonucleotides delivered within the lung may be beneficial, although rationally designed systems are needed to optimize their pharmacological response. Prompted by this need, we have developed and tested in vivo an inhalable dry powder for the prolonged delivery of a decoy oligodeoxynucleotide to NF-κB (dec-ODN), consisting of large porous particles (LPPs) based on poly(lactic-co-glycolic) acid. First, LPPs containing dec-ODN (dec-ODN LPPs) were engineered to meet the aerodynamic criteria crucial for pulmonary delivery, to gain an effective loading of dec-ODN, to sustain its release, and to preserve its structural integrity in lung lining fluids. We then investigated the effects of dec-ODN LPPs in a rat model of lung inflammation induced by the intratracheal aerosolization of LPS from Pseudomonas aeruginosa. The results show that a single intratracheal insufflation of dec-ODN LPPs reduced the bronchoalveolar neutrophil infiltration induced by LPS for up to 72 hours, whereas naked dec-ODN was able to inhibit it only at 6 hours. The persistent inhibition of neutrophil infiltrate was associated with reduced NF-κB/DNA binding activity, as well as reduced IL-6, IL-8, and mucin-2 mRNA expression in lung homogenates. We consider it noteworthy that the developed LPPs, preventing the accumulation of neutrophils and NF-κB-related gene expression, may provide a new therapeutic option for the local treatment of inflammation associated with lung disease.

PEI-engineered respirable particles delivering a decoy oligonucleotide to NF-κB: inhibiting MUC2 expression in LPS-stimulated airway epithelial cells

A specific and promising approach to limit inflammation and mucin iperproduction in chronic lung diseases relies on specific inhibition of nuclear Factor-κB (NF-κB) by a decoy oligonucleotide (dec-ODN). To fulfill the requirements dictated by translation of dec-ODN therapy in humans, inhalable dry powders were designed on a rational basis to provide drug protection, sustained release and to optimize pharmacological response. To this end, large porous particles (LPP) for dec-ODN delivery made of a sustained release biomaterial (poly(lactic-co-glycolic) acid, PLGA) and an “adjuvant” hydrophilic polymer (polyethylenimine, PEI) were developed and their effects on LPS-stimulated human airway epithelial cells evaluated. The composite PLGA/PEI particles containing dec-ODN (i.e., LPP_PEI) were successfully engineered for widespread deposition in the lung and prolonged release of intact dec-ODN in vitro. LPP_PEI caused a prolonged inhibition of IL-8 and MUC2 expression in CF human bronchial epithelial cells and human epithelial pulmonary NCI-H292 cells, respectively, as compared to naked dec-ODN. Nonetheless, as compared to previously developed LPP, the presence of PEI was essential to construct a dec-ODN delivery system able to act in mucoepidermoid lung epithelial cells. In perspective, engineering LPP with PEI may become a key factor for tuning carrier properties, controlling lung inflammation and mucin production which, in turn, can foster in vivo translation of dec-ODN therapy.

Smoking and lung cancer-induced changes in N-glycosylation of blood serum proteins

Glycosylation is a key post-translational protein modification which appears important in malignant transformation and tumor metastasis. Abnormal glycosylation of different proteins can often be measured in the blood serum. In this study, we extend our serum-based structural investigations to samples provided by patients diagnosed with lung cancer, paying particular attention to the effects of smoking on the serum glycomic traces. Following a battery of glycomic tests, we find that several fucosylated tetra-antennary structures with varying degrees of sialylation are increased in their abundances in control samples provided by the former smokers, with further elevations in the lung cancer patients who were former smokers. Further detailed investigations demonstrated that the level of outer-arm fucosylation was elevated in the control samples of the former smokers and again in the lung cancer samples provided by the former smokers. This trend was particularly noticeable for the tri- and tetra-antennary structures. Different ratios of sialylation linkages were also observed that could be correlated with the different states of health and smoking status. Decreases in the abundance levels of isomers with two and three α2,3-linked sialic acids and an increased abundance of an isomer with two α2,6-linked sialic acids were noted for a fucosylated tri-sialylated tri-antennary glycan. These results demonstrate the long-term effects of smoking on glycomic profiles and that this factor needs to be considered in these and other serum-based analyses.