Impact of Air Pollution in Airway Diseases: Role of the Epithelial Cells (Cell Models and Biomarkers).

Biomedical research is multidisciplinary and often uses integrated approaches performing different experimental models with complementary functions. This approach is important to understand the pathogenetic mechanisms concerning the effects of environmental pollution on human health. The biological activity of the substances is investigated at least to three levels using molecular, cellular, and human tissue models. Each of these is able to give specific answers to experimental problems. A scientific approach, using biological methods (wet lab), cell cultures (cell lines or primary), isolated organs (three-dimensional cell cultures of primary epithelial cells), and animal organisms, including the human body, aimed to understand the effects of air pollution on the onset of diseases of the respiratory system. Biological methods are divided into three complementary models: in vitro, ex vivo, and in vivo. In vitro experiments do not require the use of whole organisms (in vivo study), while ex vivo experiments use isolated organs or parts of organs. The concept of complementarity and the informatic support are useful tools to organize, analyze, and interpret experimental data, with the aim of discussing scientific notions with objectivity and rationality in biology and medicine. In this scenario, the integrated and complementary use of different experimental models is important to obtain useful and global information that allows us to identify the effect of inhaled pollutants on the incidence of respiratory diseases in the exposed population. In this review, we focused our attention on the impact of air pollution in airway diseases with a rapid and descriptive analysis on the role of epithelium and on the experimental cell models useful to study the effect of toxicants on epithelial cells.

Shotgun Proteomics of Isolated Urinary Extracellular Vesicles for Investigating Respiratory Impedance in Healthy Preschoolers.

Urine proteomic applications in children suggested their potential in discriminating between healthy subjects from those with respiratory diseases. The aim of the current study was to combine protein fractionation, by urinary extracellular vesicle isolation, and proteomics analysis in order to establish whether different patterns of respiratory impedance in healthy preschoolers can be characterized from a protein fingerprint. Twenty-one 3-5-yr-old healthy children, representative of 66 recruited subjects, were selected: 12 late preterm (LP) and 9 full-term (T) born. Children underwent measurement of respiratory impedance through Forced Oscillation Technique (FOT) and no significant differences between LP and T were found. Unbiased clustering, based on proteomic signatures, stratified three groups of children (A, B, C) with significantly different patterns of respiratory impedance, which was slightly worse in group A than in groups B and C. Six proteins (Tripeptidyl peptidase I (TPP1), Cubilin (CUBN), SerpinA4, SerpinF1, Thy-1 membrane glycoprotein (THY1) and Angiopoietin-related protein 2 (ANGPTL2)) were identified in order to type the membership of subjects to the three groups. The differential levels of the six proteins in groups A, B and C suggest that proteomic-based profiles of urinary fractionated exosomes could represent a link between respiratory impedance and underlying biological profiles in healthy preschool children.

Corrigendum to "Effect of High, Medium, and Low Molecular Weight Hyaluronan on Inflammation and Oxidative Stress in an In Vitro Model of Human Nasal Epithelial Cells".

[This corrects the article DOI: 10.1155/2016/8727289.].

Cigarette smoke and non-neuronal cholinergic system in the airway epithelium of COPD patients.

Acetylcholine (ACh), synthesized by Choline Acetyl-Transferase (ChAT), exerts its physiological effects via mAChRM3 in epithelial cells. We hypothesized that cigarette smoke affects ChAT, ACh, and mAChRM3 expression in the airways from COPD patients promoting airway disease. ChAT, ACh, and mAChRM3 were assessed: "ex vivo" in the epithelium from central and distal airways of COPD patients, Healthy Smoker (S) and Healthy Subjects (C), and "in vitro" in bronchial epithelial cells stimulated with cigarette smoke extract (CSE). In central airways, mAChRM3, ChAT, and ACh immunoreactivity was significantly higher in the epithelium from S and COPD than in C subjects. mAChRM3, ChAT, and ACh score of immunoreactivity was high in the metaplastia area of COPD patients. mAChRM3/ChAT and ACh/ChAT co-localization of immunoreactivity was observed in the bronchial epithelium from COPD. In vitro, CSE stimulation significantly increased mAChRM3, ChAT, and ACh expression and mAChRM3/ChAT and ACh/ChAT co-localization in 16HBE and NHBE, and increased 16HBE proliferation. Cigarette smoke modifies the levels of mAChMR3, ChAT expression, and ACh production in bronchial epithelial cells from COPD patients. Non-neuronal components of cholinergic system may have a role in the mechanism of bronchial epithelial cell proliferation, promoting alteration of normal tissue, and of related pulmonary functions.

Airway lipoxin A4/formyl peptide receptor 2-lipoxin receptor levels in pediatric patients with severe asthma.

BACKGROUND: Lipoxins are biologically active eicosanoids with anti-inflammatory properties. Lipoxin A4 (LXA4) signaling blocks asthmatic responses in human and experimental model systems. There is evidence that patients with respiratory diseases, including severe asthma (SA), display defective generation of lipoxin signals despite glucocorticoid therapy. OBJECTIVE: We investigated airway levels of formyl peptide receptor 2-lipoxin receptor (FPR2/ALXR), LXA4, and its counterregulatory compound, leukotriene B4 (LTB4), in patients with childhood asthma. We addressed the potential interplay of the LXA4-FPR2/ALXR axis and glucocorticoids in the resolution of inflammation. METHODS: We examined LXA4 and LTB4 concentrations in induced sputum supernatants from children with intermittent asthma (IA), children with SA, and healthy control (HC) children. In addition, we investigated FPR2/ALXR expression in induced sputum cells obtained from the study groups. Finally, we evaluated in vitro the molecular interaction between LXA4 and glucocorticoid receptor-based mechanisms. RESULTS: We found that children with SA have decreased LXA4 concentrations in induced sputum supernatants in comparison with children with IA. In contrast to decreases in LXA4 concentrations, LTB4 concentrations were increased in children with asthma independent of severity. LXA4 concentrations negatively correlated with LTB4 concentrations and with exacerbation numbers in children with SA. FPR2/ALXR expression was reduced in induced sputum cells of children with SA compared with that seen in HC subjects and children with IA. Finally, we describe in vitro the existence of crosstalk between LXA4 and glucocorticoid receptor at the cytosolic level mediated by G protein-coupled FPR2/ALXR in peripheral blood granulocytes isolated from HC subjects, children with IA, and children with SA. CONCLUSION: Our findings provide evidence for defective LXA4 generation and FPR2/ALXR expression that, associated with increased LTB4, might be involved in a reduction in the ability of inhaled corticosteroids to impair control of airway inflammation in children with SA.

Effect of High, Medium, and Low Molecular Weight Hyaluronan on Inflammation and Oxidative Stress in an In Vitro Model of Human Nasal Epithelial Cells.

IL-17A is involved in the activation of oxidative stress and inflammation in nasal epithelial cells. Hyaluronan (HA) in its high molecular weight form (HMW-HA) shows anti-inflammatory responses in contrast to low and medium molecular weight HA (LMW-HA and MMW-HA). The aim of this study was to investigate the pro- or anti-inflammatory biologic function of HA at different molecular weight in an in vitro model of nasal inflammation IL-17A mediated. We evaluated the ERK1/2 and IκBα phosphorylation, NF-κB signal pathway activation, ROS production, IL-8 and NOX-4 protein, and mRNA levels, in nasal epithelial cells RPMI 2650 stimulated with recombinant human (rh) IL-17A. Furthermore, the cells were treated with HMW-HA, MMW-HA, LMW-HA, and U0126. Our results showed that rhIL-17A increased the ERK1/2, IκBα phosphorylation and NF-κB signal pathway activation, ROS production, IL-8 and NOX-4 proteins, and mRNA levels. The addiction of HMW-HA or U0126 showed a significant downregulatory effect on inflammation due to the rhIL-17A stimulation in nasal epithelial cells. IL-17A is able to generate oxidative stress and inflammation via the activation of ERK1/2/NF-κB pathway in nasal epithelial cells. The HMW-HA might represent a coadjuvant of the classic anti-inflammatory/antioxidative treatment of nasal epithelial cells during IL-17A nasal inflammation.

Autocrine Acetylcholine, Induced by IL-17A via NFκB and ERK1/2 Pathway Activation, Promotes MUC5AC and IL-8 Synthesis in Bronchial Epithelial Cells.

IL-17A is overexpressed in the lung during acute neutrophilic inflammation. Acetylcholine (ACh) increases IL-8 and Muc5AC production in airway epithelial cells. We aimed to characterize the involvement of nonneuronal components of cholinergic system on IL-8 and Muc5AC production in bronchial epithelial cells stimulated with IL-17A. Bronchial epithelial cells were stimulated with recombinant human IL-17A (rhIL-17A) to evaluate the ChAT expression, the ACh binding and production, the IL-8 release, and the Muc5AC production. Furthermore, the effectiveness of PD098,059 (inhibitor of MAPKK activation), Bay11-7082 (inhibitor of IkBα phosphorylation), Hemicholinium-3 (HCh-3) (choline uptake blocker), and Tiotropium bromide (Spiriva®) (anticholinergic drug) was tested in our in vitro model. We showed that rhIL-17A increased the expression of ChAT, the levels of ACh binding and production, and the IL-8 and Muc5AC production in stimulated bronchial epithelial cells compared with untreated cells. The pretreatment of the cells with PD098,059 and Bay11-7082 decreased the ChAT expression and the ACh production/binding, while HCh-3 and Tiotropium decreased the IL-8 and Muc5AC synthesis in bronchial epithelial cells stimulated with rhIL-17A. IL-17A is involved in the IL-8 and Muc5AC production promoting, via NFκB and ERK1/2 pathway activation, the synthesis of ChAT, and the related activity of autocrine ACh in bronchial epithelial cells.

Cigarette smoke affects IL-17A, IL-17F and IL-17 receptor expression in the lung tissue: Ex vivo and in vitro studies.

Cigarette smoke is a risk factor for Chronic Obstructive Pulmonary Disease (COPD). Th-17 cytokines are involved in the pathogenesis of COPD. We aimed to evaluate the role of cigarette smoke on the expression of IL-17A, IL-17F and IL-17R in airways of COPD patients. Epithelial and subepithelial immunoreactivity for IL-17A, IL-17F and IL-17R was assessed in surgical specimens from COPD patients (n=15) and from healthy subjects (HC) (n=10) by immunohistochemistry. In vitro, human epithelial cell line 16HBE and A549 as well as PBMC from normal donors were stimulated with cigarette smoke extract (CSE) (0%, 2.5%, 5%, 10%) to evaluate the IL-17A, IL-17F and IL-17R expression by flow cytometry. Furthermore, rhIL-17A and CSE stimulation was evaluated on proliferation and apoptosis in 16HBE and in A549. In central and distal airways immunoreactivity for IL-17A, IL-17F and IL-17R significantly increased in the epithelium and IL-17A in the subepithelium from COPD than in HC. In distal airway, immunoreactivity for IL-17F increased in the subepithelium of COPD than in HC. IL-17A immunoreactivity positively correlate with IL-17R and total pack years in the epithelium from central and distal airways of COPD patients. In vitro, CSE stimulation significantly increased IL-17F and IL-17R in 16HBE (2.5%) and A549 (5%) while IL-17A and IL-17F in PBMC (10%). IL-17A and CSE stimulation, rather than CSE or rhIL-17A alone, significantly increased proliferation in 16HBE and apoptosis in A549. Cigarette smoke increases Th17 immunity in lung tissue of COPD patients, promoting the mechanism of proliferation and apoptosis in airway epithelial cells.

Acetylcholine leads to signal transducer and activator of transcription 1 (STAT-1) mediated oxidative/nitrosative stress in human bronchial epithelial cell line.

The induction of nitric oxide synthase (iNOS) expression via the signal transducer and activator of transcription 1 (STAT-1) is involved in the mechanism of oxidative/nitrosative stress. We investigated whether acetylcholine (ACh) generates oxidative/nitrosative stress in bronchial epithelial cells during airway inflammation of COPD and evaluated the effects of Tiotropium, a once-daily antimuscarinic drug, and Olodaterol, a long-acting ß2-agonist on these mechanisms. Human bronchial epithelial cells (16-HBE) were stimulated (4h, 37°C) with induced sputum supernatants (ISSs) from healthy controls (HC) (n=10), healthy smokers (HS) (n=10) or COPD patients (n=10), as well as with ACh (from 1µM to 100µM). The activation of STAT-1 pathway (STAT-1Ser727 and STAT-1Tyr701) and iNOS was evaluated in the cell lysates by Western blot analysis as well as nitrotyrosine levels by ELISA, while reactive oxygen species (ROS) were evaluated by flow cytometry. Finally, the effect of Tiotropium (Spiriva®) (100nM), alone or in combination with Olodaterol (1nM), was tested in this model. ISSs from COPD patients significantly increased the phosphorylation of STAT-1Ser727 and STAT-1Tyr701, iNOS and ROS/Nitrotyrosine when compared with ISSs from HC or HS subjects in 16-HBE cells. Furthermore, synthetic ACh increased all these parameters in stimulated 16HBE when compared with untreated cells. Tiotropium and Olodaterol reduced the oxidative/nitrosative stress generated by ACh and ISSs. We concluded that ACh mediated the oxidative/nitrosative stress involving the STAT-1 pathway activation in human bronchial epithelial cells during COPD. ß2-Long acting and antimuscarinic drugs, normally used in the treatment of COPD as bronchodilator, might be able to control these cellular events.

Effect of nebulized beclomethasone on airway inflammation and clinical status of children with allergic asthma and rhinitis: a randomized, double-blind, placebo-controlled study.

We aimed to evaluate the therapeutic effect of nebulized beclomethasone dipropionate (nBDP) on both allergic asthma and rhinitis. In a randomized, double-blind, placebo-controlled study, 40 children (mean age 10.7 ± 2.1 years) with allergic asthma and rhinitis received either nBDP (daily dose of 800 µg, administered twice daily) or placebo for 4 weeks (with a face mask), after a 2-week run-in period of clinical assessment. Nasal and oral fractional exhaled nitric oxide (FeNO) measurements together with pulmonary function tests, nasal and oral exhaled breath condensate (EBC) collection for pH and interleukin-5 (IL-5) measurements as well as nasal and bronchial symptom scores were obtained at baseline and after 4-week treatment. A significant improvement in oral FeNO, oral and nasal EBC IL-5 and nasal EBC pH was observed in the nBDP group when comparing the values with baseline, together with an improvement in symptom score of the visual analogue scale, nasal obstruction, sneezing, rhinorrhea, breathing difficulty, cough, wheezing and sleep disturbance (nBDP end treatment vs. baseline, Wilcoxon signed-rank test). nBDP was more effective than placebo (ANCOVA test) in improving [difference Δ = response after treatment at the last visit (active or placebo) - value at baseline] nasal pH, oral IL-5, oral FeNO, forced expiratory volume in 1 s, forced expiratory volume in 1 s/forced vital capacity, peek expiratory flow, visual analogue scale, breathing difficulty, cough, wheezing and sleep disturbance scores. No differences were observed between the nBDP and the placebo group for symptom score of rhinitis. nBDP is a useful treatment for airway inflammation and clinical status in children with concomitant allergic asthma and rhinitis.

Autophagy/Mitophagy in Airway Diseases: Impact of Oxidative Stress on Epithelial Cells.

Autophagy is the key process by which the cell degrades parts of itself within the lysosomes. It maintains cell survival and homeostasis by removing molecules (particularly proteins), subcellular organelles, damaged cytoplasmic macromolecules, and by recycling the degradation products. The selective removal or degradation of mitochondria is a particular type of autophagy called mitophagy. Various forms of cellular stress (oxidative stress (OS), hypoxia, pathogen infections) affect autophagy by inducing free radicals and reactive oxygen species (ROS) formation to promote the antioxidant response. Dysfunctional mechanisms of autophagy have been found in different respiratory diseases such as chronic obstructive lung disease (COPD) and asthma, involving epithelial cells. Several existing clinically approved drugs may modulate autophagy to varying extents. However, these drugs are nonspecific and not currently utilized to manipulate autophagy in airway diseases. In this review, we provide an overview of different autophagic pathways with particular attention on the dysfunctional mechanisms of autophagy in the epithelial cells during asthma and COPD. Our aim is to further deepen and disclose the research in this direction to stimulate the develop of new and selective drugs to regulate autophagy for asthma and COPD treatment.

IκB kinase-driven nuclear factor-κB activation in patients with asthma and chronic obstructive pulmonary disease.

BACKGROUND: Nuclear factor-κB (NF-κB) is a transcriptional factor of different inflammatory patterns involved in asthma and chronic obstructive pulmonary disease (COPD) that is tightly controlled by IκB kinase (IKK) complex. OBJECTIVE: We investigated the dysregulation of IKK-driven NF-κB activation in patients with asthma and COPD. METHODS: We assessed IKKα and IKKß expression and activation, their regulation by glucocorticosteroids, and their involvement in IL-8 synthesis in PBMCs isolated from asthmatic patients, healthy smokers (HSs), patients with COPD, and control subjects. PBMCs from control subjects were stimulated with TNF-α and cigarette smoke extract in the presence or absence of fluticasone propionate (FP), L-glutathione reduced, or both, and IKK activation and IL-8 release were evaluated. RESULTS: IKKα activity was higher in patients with COPD and HSs than in asthmatic patients and control subjects. IKKß activity was higher in asthmatic patients, HSs, and patients with COPD than in control subjects. In vitro FP treatment induced inhibition of both IKKα and IKKß activity in PBMCs from asthmatic patients, patients with COPD, and HSs, although IKKß activity was more sensitive to FP than that of IKKα. FP reduced the IL-8 released from PBMCs of asthmatic patients, patients with COPD, and HSs, although IL-8 inhibition was higher in asthmatic patients than in patients with COPD and HSs. FP reduced IKKα and IKKß activities in TNF-α and cigarette smoke extract-treated PBMCs, with higher levels of inhibition for IKKß than IKKα activity. L-glutathione reduced improved the downregulatory effects of FP on IKKα and IL-8 levels. CONCLUSION: Based on differential activation of IKKα and IKKß, our findings suggest a different profile in the upstream regulation of the IKK-driven NF-κB system in asthmatic patients and patients with COPD. These differences in the regulation of the inflammatory process may explain, at least in part, the different pharmacologic responses in these patients.

Overview of the Mechanisms of Oxidative Stress: Impact in Inflammation of the Airway Diseases.

Inflammation of the human lung is mediated in response to different stimuli (e.g., physical, radioactive, infective, pro-allergenic or toxic) such as cigarette smoke and environmental pollutants. They often promote an increase in inflammatory activities in the airways that manifest themselves as chronic diseases (e.g., allergic airway diseases, asthma, chronic bronchitis/chronic obstructive pulmonary disease (COPD) or even lung cancer). Increased levels of oxidative stress (OS) reduce the antioxidant defenses, affect the autophagy/mitophagy processes, and the regulatory mechanisms of cell survival, promoting inflammation in the lung. In fact, OS potentiate the inflammatory activities in the lung, favoring the progression of chronic airway diseases. OS increases the production of reactive oxygen species (ROS), including superoxide anions (O2-), hydroxyl radicals (OH) and hydrogen peroxide (H2O2), by the transformation of oxygen through enzymatic and non-enzymatic reactions. In this manner, OS reduces endogenous antioxidant defenses in both nucleated and non-nucleated cells. The production of ROS in the lung can derive from both exogenous insults (cigarette smoke or environmental pollution) and endogenous sources such as cell injury and/or activated inflammatory and structural cells. In this review, we describe the most relevant knowledge concerning the functional interrelation between the mechanisms of OS and inflammation in airway diseases.

Non-Coding RNAs in Airway Diseases: A Brief Overview of Recent Data.

Inflammation of the human lung is mediated in response to different stimuli (e.g., physical, radioactive, infective, pro-allergenic, or toxic) such as cigarette smoke and environmental pollutants. These stimuli often promote an increase in different inflammatory activities in the airways, manifesting themselves as chronic diseases (e.g., allergic airway diseases, asthma chronic bronchitis/chronic obstructive pulmonary disease, or even lung cancer). Non-coding RNA (ncRNAs) are single-stranded RNA molecules of few nucleotides that regulate the gene expression involved in many cellular processes. ncRNA are molecules typically involved in the reduction of translation and stability of the genes of mRNAs s. They regulate many biological aspects such as cellular growth, proliferation, differentiation, regulation of cell cycle, aging, apoptosis, metabolism, and neuronal patterning, and influence a wide range of biologic processes essential for the maintenance of cellular homeostasis. The relevance of ncRNAs in the pathogenetic mechanisms of respiratory diseases has been widely established and in the last decade many papers were published. However, once their importance is established in pathogenetic mechanisms, it becomes important to further deepen the research in this direction. In this review we describe several of most recent knowledge concerning ncRNA (overall miRNAs) expression and activities in the lung.

Airway epithelial dysfunction and mesenchymal transition in chronic obstructive pulmonary disease: Role of Oct-4.

The airway epithelium is a dynamic tissue that undergoes slow but constant renewal. Dysregulation of airway epithelial function related to cigarette smoke exposure plays an important role in the pathophysiology of COPD. Oct4 is a transcription factor responsible for maintaining cellular self-renewal and regeneration, and CD146 and CD105/Endoglin are adhesion molecules involved in cell proliferation, differentiation, epithelial-mesenchymal-transition and tissue remodeling. Bronchial biopsy specimens (BBs) were obtained from 7 healthy controls (HC) and 10 COPD and subjected to paraffin embedding; BBs from HC were also used for epithelial cell expansion and pHBEC/ALI (air-liquid interface) culture. pHBEC/ALI were exposed to cigarette smoke extract (CSE) for 7, 14 and 21 days. In BBs, Oct4, CD146 and CD105 were evaluated by immunohistochemistry. In pHBEC/ALI, the expression of Oct4, CD146, CD105 and acetyl-αtubulin was evaluated by Western Blot, MUC5AC and IL-8 measurements by ELISA. The Oct4 epithelial immunoreactivity was lower in COPD than in HC, whilst CD146 and CD105 expression was higher in COPD than in HC. In pHBEC/ALI, Transepithelial Electrical Resistance values, measured over 7 to 21 days of differentiation, decreased by 18% (2.5% CSE) and 29% (5% CSE) compared to untreated samples. Oct4 and acetyl-αtubulin were induced after one-week differentiation and downregulated by CSE in reconstituted epithelium; CD146, CD105, MUC5AC and IL-8 were increased by CSE. Oct4 de-regulation and CD146 and CD105 overexpression, induced by cigarette smoke exposure, might play a role in airway epithelial dysfunction by causing changes in self-renewal and mesenchymal transition mechanisms, leading to alteration of epithelium homeostasis and abnormal tissue remodeling involved in progression of COPD.

Endotyping Seasonal Allergic Rhinitis in Children: A Cluster Analysis.

BACKGROUND: Seasonal Allergic Rhinitis (SAR) is a heterogeneous inflammatory disease. We hypothesized that a cluster analysis based on the evaluation of cytokines in nasal lavage (NL) could characterize distinctive SAR endotypes in children. METHODS: This cross-sectional study enrolled 88 children with SAR. Detailed medical history was obtained by well-trained physicians. Quality of life and sleep quality were assessed through standardized questionnaires [Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ) and Pittsburgh Sleep Quality Index (PSQI) respectively]. Children were grouped through K-means clustering using Interleukin (IL)-5, IL-17, IL-23, and Interferon (INF)-γ in NL. RESULTS: Out of the 88 patients enrolled, 80 were included in the cluster analysis, which revealed three SAR endotypes. Cluster 1 showed lower levels of IL-5 and IL-17 and intermediate levels of IL-23 and IFN-γ; Cluster 2 had higher levels of IL-5 and intermediate levels of IL-17, IL-23, and IFN-γ; Cluster 3 showed higher levels of IL-17, IL-23, and IFN-γ and intermediate levels of IL-5. Cluster 1 showed intermediate values of nasal pH and nasal nitric oxide (nNO), and a lower percentage of neutrophils at nasal cytology than Clusters 2 and 3. Cluster 2 had a lower level of nasal pH, a higher nNO, higher scores in the ocular domain of PRQLQ, and worse sleep quality than Clusters 1 and 3. Cluster 3 showed a higher percentage of neutrophils at nasal cytology than Clusters 1 and 2. CONCLUSIONS: Our study identified three endotypes based on the evaluation of cytokines in NL, highlighting that childhood SAR is characterized by heterogeneous inflammatory cytokines.

PBDEs affect inflammatory and oncosuppressive mechanisms via the EZH2 methyltransferase in airway epithelial cells.

AIMS: We aimed to investigate the effect of PBDEs (47, 99, 209) on cellular events involved in epigenetic modification, inflammation, and epithelial mesenchymal transition (EMT). MATERIALS AND METHODS: We studied: 1) ERK1/2 phosphorylation; 2) Enhancer of Zester Homolog 2 (EZH2); 3) Histone H3 tri-methylated in lysine 27 (H3K27me3); 4) K-RAS; 5) silencing disabled homolog 2-interacting protein gene (DAB2IP), 6) let-7a; 7) Muc5AC/Muc5B, and 8) IL-8 in a 3D in vitro model of epithelium obtained with primary Normal Human Bronchial Epithelial cells (pNHBEs) or A549 cell line, chronically exposed to PBDEs (47, 99, 209). KEY FINDINGS: PBDEs (10 nM, 100 nM and 1 µM) increased ERK1/2 phosphorylation, and EZH2, H3K27me3, and K-RAS protein expression, while decreased DAB2IP and Let-7a transcripts in pNHBEs ALI culture. Furthermore PBDEs (47, 99) (100 nM) increased Muc5AC and Muc5B mRNA, and PBDE 47 (100 nM) IL-8 mRNA via EZH2 in pNHBEs. Finally, PBDEs (100 nM) affected EZH2, H3K27me3, K-RAS protein expression, and DAB2IP, Let-7a transcripts and cell invasion in A549 cells. Gsk343 (methyltransferase EZH2 inhibitor) (1 mM) and U0126 (inhibitor of MEK1/2) (10 µM) were used to show the specific effect of PBDEs. SIGNIFICANCE: PBDE inhalation might promote inflammation/cancer via EZH2 methyltransferase activity and H3K27me3, k-RAS and ERk1/2 involvement, generating adverse health outcomes of the human lung.

Can PBDEs affect the pathophysiologic complex of epithelium in lung diseases?

Brominated flame-retardant (BFRs) exposure promotes multiple adverse health outcomes involved in oxidative stress, inflammation, and tissues damage. We investigated BFR effects, known as polybrominated diphenyl ethers (PBDEs) (47, 99 and 209) in an air-liquid-interface (ALI) airway tissue derived from A549 cell line, and compared with ALI culture of primary human bronchial epithelial cells (pHBEC). The cells, exposed to PBDEs (47, 99 and 209) (0.01-1 µM) for 24 h, were studied for IL-8, Muc5AC and Muc5B (mRNAs and proteins) production, as well as NOX-4 (mRNA) expression. Furthermore, we evaluated tight junction (TJ) integrity by Trans-Epithelial Electrical Resistance (TEER) measurements, and zonula occludens-1 (ZO-1) expression in the cells, and pH variations and rheological properties (elastic G', and viscous G″, moduli) in apical washes of ALI cultures. N-acetylcysteine (NAC) (10 mM) effects were tested in our experimental model of A549 cells. PBDEs (47, 99 and 209) exposure decreased TEER, ZO-1 and pH values, and increased IL-8, Muc5AC, Muc5B (mRNAs and proteins), NOX-4 (mRNA), and rheological parameters (G', G″) in ALI cultures of A549 cell line and pHBEC. NAC inhibited PBDE effects in A549 cells. PBDE inhalation might impairs human health of the lungs inducing oxidative stress, inflammatory response, loss of barrier integrity, unchecked mucus production, as well as altered physicochemical and biological properties of the fluids in airway epithelium. The treatment with anti-oxidants restored the negative effects of PBDEs in epithelial cells.

A 3D "In Vitro" Model to Study Hyaluronan Effect in Nasal Epithelial Cell Line Exposed to Double-Stranded RNA Poly(I:C).

Environmental agents, including viral and bacterial infectious agents, are involved in the alteration of physicochemical and biological parameters in the nasal epithelium. Hyaluronan (HA) has an important role in the regulation of tissue healing properties. High molecular weight HA (HMW-HA) shows greater anti-inflammatory responses than medium molecular weight HA (MMW-HA) and low molecular weight HA (LMW-HA). We investigated the effect of HMW-HA, MMW-HA and LMW-HA on the regulation of physicochemical and biological parameters in an "in vitro" model that might mimic viral infections of the nasal epithelium. Human nasal epithelial cell line RPMI2650 was stimulated with double-stranded RNA (dsRNA) Poly(I:C) for 5 days in air-liquid-interface (ALI) culture (3D model of airway tissue). dsRNA Poly(I:C) treatment significantly decreased transepithelial electrical resistance (TEER) in the stratified nasal epithelium of RPMI2650 and increased pH values, rheological parameters (elastic G' and viscous G"), and Muc5AC and Muc5B production in the apical wash of ALI culture of RPMI2650 in comparison to untreated cells. RPMI2650 treated with dsRNA Poly(I:C) in the presence of HMW-HA showed lower pH values, Muc5AC and Muc5B production, and rheological parameters, as well as increased TEER values in ALI culture, compared to cells treated with Poly(I:C) alone or pretreated with LMW-HA and MMW-HA. Our 3D "in vitro" model of epithelium suggests that HMW-HA might be a coadjuvant in the pharmacological treatment of viral infections, allowing for the control of some physicochemical and biological properties affecting the epithelial barrier of the nose during infection.