Comparative cytoprotective effects of carbocysteine and fluticasone propionate in cigarette smoke extract-stimulated bronchial epithelial cells

Role of airway epithelium in viral respiratory infections: Can carbocysteine prevent or mitigate them?

Alterations in airway epithelial homeostasis increase viral respiratory infections risk. Viral infections frequently are associated with chronic obstructive pulmonary disease (COPD) exacerbations, events that dramatically promote disease progression. Mechanism promoting the main respiratory viruses entry and virus-evocated innate and adaptive immune responses have now been elucidated, and an oxidative stress central role in these pathogenic processes has been recognized. Presence of reactive oxygen species in macrophages and other cells allows them to eliminate virus, but its excess alters the balance between innate and adaptive immune responses and proteases/anti-proteases and leads to uncontrolled inflammation, tissue damage, and hypercoagulability. Different upper and lower airway cell types also play a role in viral entry and infection. Carbocysteine is a muco-active drug with anti-oxidant and anti-inflammatory properties used for the management of several chronic respiratory diseases. Although the use of anti-oxidants has been proposed as an effective strategy in COPD exacerbations management, the molecular mechanisms that explain carbocysteine efficacy have not yet been fully clarified. The present review describes the most relevant features of the common respiratory virus pathophysiology with a focus on epithelial cells and oxidative stress role and reports data supporting a putative role of carbocysteine in viral respiratory infections.

An insight into role of amino acids as antioxidants via NRF2 activation

Oxidative stress can affect the protein, lipids, and DNA of the cells and thus, play a crucial role in several pathophysiological conditions. It has already been established that oxidative stress has a close association with inflammation via nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. Amino acids are notably the building block of proteins and constitute the major class of nitrogen-containing natural products of medicinal importance. They exhibit a broad spectrum of biological activities, including the ability to activate NRF2, a transcription factor that regulates endogenous antioxidant responses. Moreover, amino acids may act as synergistic antioxidants as part of our dietary supplementations. This has aroused research interest in the NRF2-inducing activity of amino acids. Interestingly, amino acids' activation of NRF2-Kelch-like ECH-associated protein 1 (KEAP1) signaling pathway exerts therapeutic effects in several diseases. Therefore, the present review will discuss the relationship between different amino acids and activation of NRF2-KEAP1 signaling pathway pinning their anti-inflammatory and antioxidant properties. We also discussed amino acids formulations and their applications as therapeutics. This will broaden the prospect of the therapeutic applications of amino acids in a myriad of inflammation and oxidative stress-related diseases. This will provide an insight for designing and developing new chemical entities as NRF2 activators.

Effects of condensates from volcanic fumaroles and cigarette smoke extracts on airway epithelial cells

The impact of volcanic airborne products on airway epithelium homeostasis is largely unknown. This study assessed the effects of volcanic Fumarole Condensates (FC) alone or combined with Cigarette Smoke Extracts (CSE) on airway epithelial cells (16HBE and A549). Chemical composition of FC was analyzed by gas chromatography and HPLC. Cells were exposed to FC and IL-33 and IL-8 were assessed. The effects of FC and CSE on cell injury were evaluated assessing cell metabolism/cell viability, mitochondrial stress, cell apoptosis/cell necrosis, and cell proliferation. FC contained: water vapor (70-97%), CO2 (3-30%), acid gases (H2S, SO2, HCl, HF) around 1%. FC increased the intracellular IL-33 but differently modulated IL-33 and IL-8 gene expression and IL-8 release in the tested cell lines. FC without/with CSE: (a) increased cell metabolism/cell viability in 16HBE, while decreased it in A549; (b) increased mitochondrial stress in both cell types. FC with CSE increased cell necrosis in A549 in comparison to CSE alone. CSE reduced cell proliferation in 16HB,E while increased it in A549 and FC counteracted these effects in both cell types. Overall, FC induce a pro-inflammatory profile associated to a metabolic reprogramming without a relevant toxicity also in presence of CSE in airway epithelial cells.

Use of thiols and implications for the use of inhaled corticosteroids in the presence of oxidative stress in COPD

BACKGROUND

Oxidative stress and persistent airway inflammation are thought to be important contributors to the development of chronic obstructive pulmonary disease (COPD). This review summarizes the evidence for targeting oxidative stress and inflammation in patients with COPD with mucolytic/antioxidant thiols and inhaled corticosteroids (ICS), either alone or in combination.

MAIN BODY

Oxidative stress is increased in COPD, particularly during acute exacerbations. It can be triggered by oxidant air pollutants and cigarette smoke and/or by endogenous reactive oxygen species (ROS) released from mitochondria and activated inflammatory, immune and epithelial cells in the airways, together with a reduction in endogenous antioxidants such as glutathione (GSH). Oxidative stress also drives chronic inflammation and disease progression in the airways by activating intracellular signalling pathways and the release of further inflammatory mediators. ICS are anti-inflammatory agents currently recommended for use with long-acting bronchodilators to prevent exacerbations in patients with moderate-to-severe COPD, especially those with eosinophilic airway inflammation. However, corticosteroids can also increase oxidative stress, which may in turn reduce corticosteroid sensitivity in patients by several mechanisms. Thiol-based agents such as erdosteine, N-acetyl L-cysteine (NAC) and S-carboxymethylcysteine (S-CMC) are mucolytic agents that also act as antioxidants. These agents may reduce oxidative stress directly through the free sulfhydryl groups, serving as a source of reducing equivalents and indirectly though intracellular GSH replenishment. Few studies have compared the effects of corticosteroids and thiol agents on oxidative stress, but there is some evidence for greater antioxidant effects when they are administered together. The current Global Initiative for Chronic Obstructive Lung Disease (GOLD) report supports treatment with antioxidants (erdosteine, NAC, S-CMC) in addition to standard-of-care therapy as they have been demonstrated to reduce COPD exacerbations. However, such studies have demonstrated that NAC and S-CMC reduced the exacerbation risk only in patients not treated with ICS, whereas erdosteine reduced COPD exacerbations irrespective of concomitant ICS use suggesting that erdosteine has additional pharmacological actions to ICS.

CONCLUSIONS

Further clinical trials of antioxidant agents with and without ICS are needed to better understand the place of thiol-based drugs in the treatment of patients with COPD.

Oxidative Stress, Environmental Pollution, and Lifestyle as Determinants of Asthma in Children

Exposure to cigarette smoke, allergens, viruses, and other environmental contaminants, as well as a detrimental lifestyle, are the main factors supporting elevated levels of airway oxidative stress. Elevated oxidative stress results from an imbalance in reactive oxygen species (ROS) production and efficiency in antioxidant defense systems. Uncontrolled increased oxidative stress amplifies inflammatory processes and tissue damage and alters innate and adaptive immunity, thus compromising airway homeostasis. Oxidative stress events reduce responsiveness to corticosteroids. These events can increase risk of asthma into adolescence and prompt evolution of asthma toward its most severe forms. Development of new therapies aimed to restore oxidant/antioxidant balance and active interventions aimed to improve physical activity and quality/quantity of food are all necessary strategies to prevent asthma onset and avoid in asthmatics evolution toward severe forms of the disease.

Cigarette Smoke Impairs Airway Epithelial Wound Repair: Role of Modulation of Epithelial-Mesenchymal Transition Processes and Notch-1 Signaling

Cigarette smoke (CS) induces oxidative stress and chronic inflammation in airway epithelium. It is a major risk factor for respiratory diseases, characterized by epithelial injury. The impact of CS on airway epithelial repair, which involves epithelial-mesenchymal transition (EMT) and the Notch-1 pathway, is incompletely understood. In this study, we used primary bronchial epithelial cells (PBECs) to evaluate the effect of CS on epithelial repair and these mechanisms. The effect of CS and/or TGF-beta1 on wound repair, various EMT and Notch-1 pathway markers and epithelial cell markers (TP63, SCGB1A) was assessed in PBECs cultured submerged, at the air–liquid interface (ALI) alone and in co-culture with fibroblasts. TGF-beta1 increased epithelial wound repair, activated EMT (shown by decrease in E-cadherin, and increases in vimentin, SNAIL1/SNAIL2/ZEB1), and increased Notch-1 pathway markers (NOTCH1/JAGGED1/HES1), MMP9, TP63, SCGB1A1. In contrast, CS decreased wound repair and vimentin, NOTCH1/JAGGED1/HES1, MMP9, TP63, SCGB1A1, whereas it activated the initial steps of the EMT (decrease in E-cadherin and increases in SNAIL1/SNAIL2/ZEB1). Using combined exposures, we observed that CS counteracted the effects of TGF-beta1. Furthermore, Notch signaling inhibition decreased wound repair. These data suggest that CS inhibits the physiological epithelial wound repair by interfering with the normal EMT process and the Notch-1 pathway.

The Role of Organosulfur Compounds as Nrf2 Activators and Their Antioxidant Effects

Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling has become a key pathway for cellular regulation against oxidative stress and inflammation, and therefore an attractive therapeutic target. Several organosulfur compounds are reportedly activators of the Nrf2 pathway. Organosulfur compounds constitute an important class of therapeutic agents in medicinal chemistry due to their ability to participate in biosynthesis, metabolism, cellular functions, and protection of cells from oxidative damage. Sulfur has distinctive chemical properties such as a large number of oxidation states and versatility of reactions that promote fundamental biological reactions and redox biochemistry. The presence of sulfur is responsible for the peculiar features of organosulfur compounds which have been utilized against oxidative stress-mediated diseases. Nrf2 activation being a key therapeutic strategy for oxidative stress is closely tied to sulfur-based chemistry since the ability of compounds to react with sulfhydryl (-SH) groups is a common property of Nrf2 inducers. Although some individual organosulfur compounds have been reported as Nrf2 activators, there are no papers with a collective analysis of these Nrf2-activating organosulfur compounds which may help to broaden the knowledge of their therapeutic potentials and motivate further research. In line with this fact, for the first time, this review article provides collective and comprehensive information on Nrf2-activating organosulfur compounds and their therapeutic effects against oxidative stress, thereby enriching the chemical and pharmacological diversity of Nrf2 activators.

Clinical Efficacy of Carbocysteine in COPD: Beyond the Mucolytic Action

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease with a versatile and complicated profile, being the fourth most common single cause of death worldwide. Several research groups have been trying to identify possible therapeutic approaches to treat COPD, such as the use of mucoactive drugs, which include carbocysteine. However, their role in the treatment of patients suffering from COPD remains controversial due to COPD's multifaceted profile. In the present review, 72 articles, published in peer-reviewed journals with high impact factors, are analyzed in order to provide significant insight and increase the knowledge about COPD considering the important contribution of carbocysteine in reducing exacerbations via multiple mechanisms. Carbocysteine is in fact able to modulate mucins and ciliary functions, and to counteract viral and bacterial infections as well as oxidative stress, offering cytoprotective effects. Furthermore, carbocysteine improves steroid responsiveness and exerts anti-inflammatory activity. This analysis demonstrates that the use of carbocysteine in COPD patients represents a well-tolerated treatment with a favorable safety profile, and might contribute to a better quality of life for patients suffering from this serious illness.

High Mobility Group Box 1: Biological Functions and Relevance in Oxidative Stress Related Chronic Diseases

In the early 1970s, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and named high-mobility group (HMG) proteins. High-mobility group box 1 (HMGB1) is the most studied HMG protein that detects and coordinates cellular stress response. The biological function of HMGB1 depends on its subcellular localization and expression. It plays a critical role in the nucleus and cytoplasm as DNA chaperone, chromosome gatekeeper, autophagy maintainer, and protector from apoptotic cell death. HMGB1 also functions as an extracellular alarmin acting as a damage-associated molecular pattern molecule (DAMP). Recent findings describe HMGB1 as a sophisticated signal of danger, with a pleiotropic function, which is useful as a clinical biomarker for several disorders. HMGB1 has emerged as a mediator in acute and chronic inflammation. Furthermore, HMGB1 targeting can induce beneficial effects on oxidative stress related diseases. This review focus on HMGB1 redox status, localization, mechanisms of release, binding with receptors, and its activities in different oxidative stress-related chronic diseases. Since a growing number of reports show the key role of HMGB1 in socially relevant pathological conditions, to our knowledge, for the first time, here we analyze the scientific literature, evaluating the number of publications focusing on HMGB1 in humans and animal models, per year, from 2006 to 2021 and the number of records published, yearly, per disease and category (studies on humans and animal models).

Metformin alleviates chronic obstructive pulmonary disease and cigarette smoke extract-induced glucocorticoid resistance by activating the nuclear factor E2-related factor 2/heme oxygenase-1 signaling pathway

Chronic obstructive pulmonary disease (COPD) is an important healthcare problem worldwide. Often, glucocorticoid (GC) resistance develops during COPD treatment. As a classic hypoglycemic drug, metformin (MET) can be used as a treatment strategy for COPD due to its anti-inflammatory and antioxidant effects, but its specific mechanism of action is not known. We aimed to clarify the role of MET on COPD and cigarette smoke extract (CSE)-induced GC resistance. Through establishment of a COPD model in rats, we found that MET could improve lung function, reduce pathological injury, as well as reduce the level of inflammation and oxidative stress in COPD, and upregulate expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), multidrug resistance protein 1 (MRP1), and histone deacetylase 2 (HDAC2). By establishing a model of GC resistance in human bronchial epithelial cells stimulated by CSE, we found that MET reduced secretion of interleukin-8, and could upregulate expression of Nrf2, HO-1, MRP1, and HDAC2. MET could also increase the inhibition of MRP1 efflux by MK571 significantly, and increase expression of HDAC2 mRNA and protein. In conclusion, MET may upregulate MRP1 expression by activating the Nrf2/HO-1 signaling pathway, and then regulate expression of HDAC2 protein to reduce GC resistance.

Carbocysteine Modifies Circulating miR-21, IL-8, sRAGE, and fAGEs Levels in Mild Acute Exacerbated COPD Patients: A Pilot Study

Patients with Chronic Obstructive Pulmonary Disease (COPD) periodically experience acute exacerbation (AECOPD). Carbocysteine represents a valid add on therapy in COPD by exerting antioxidant and anti-inflammatory activities. The in vivo effects of carbocysteine on inflammatory markers are not yet fully understood. The aims of this study were to assess: (i) miR-21, IL-8, soluble Receptor for Advanced Glycation End Products (sRAGE), and fluorescent Advanced Glycation End Products (fAGEs) in control subjects (n = 9), stable (n = 9), and AECOPD patients (n = 24); and (ii) whether carbocysteine modifies these markers and the functional parameters in mild AECOPD patients. Mild AECOPD patients received or not carbocysteine along with background inhalation therapy for 20 days. At the onset and at the end of the observation period, the following parameters were evaluated: FEV1, FEF25–75%, CAT questionnaire; miR-21 by Real Time PCR; IL-8 and sRAGE by ELISA; and fAGEs by spectro-fluorescence method. COPD patients showed higher levels of miR-21, IL-8, fAGEs and lower levels of sRAGE compared to that of controls. miR-21 inversely correlated with FEV1. IL-8 and fAGEs were significantly different in stable and exacerbated COPD patients. Carbocysteine improved symptoms, FEV1 and FEF25–75%, increased sRAGE, and reduced miR-21, IL-8, and fAGEs in mild AECOPD patients. The present study provides compelling evidence that carbocysteine may help to manage mild AECOPD by downregulating some parameters of systemic inflammation.

Cellular and Molecular Signatures of Oxidative Stress in Bronchial Epithelial Cell Models Injured by Cigarette Smoke Extract

Exposure of the airways epithelium to environmental insults, including cigarette smoke, results in increased oxidative stress due to unbalance between oxidants and antioxidants in favor of oxidants. Oxidative stress is a feature of inflammation and promotes the progression of chronic lung diseases, including Chronic Obstructive Pulmonary Disease (COPD). Increased oxidative stress leads to exhaustion of antioxidant defenses, alterations in autophagy/mitophagy and cell survival regulatory mechanisms, thus promoting cell senescence. All these events are amplified by the increase of inflammation driven by oxidative stress. Several models of bronchial epithelial cells are used to study the molecular mechanisms and the cellular functions altered by cigarette smoke extract (CSE) exposure, and to test the efficacy of molecules with antioxidant properties. This review offers a comprehensive synthesis of human in-vitro and ex-vivo studies published from 2011 to 2021 describing the molecular and cellular mechanisms evoked by CSE exposure in bronchial epithelial cells, the most used experimental models and the mechanisms of action of cellular antioxidants systems as well as natural and synthetic antioxidant compounds.

Oxidative Stress Promotes Corticosteroid Insensitivity in Asthma and COPD

Corticosteroid insensitivity is a key characteristic of patients with severe asthma and COPD. These individuals experience greater pulmonary oxidative stress and inflammation, which contribute to diminished lung function and frequent exacerbations despite the often and prolonged use of systemic, high dose corticosteroids. Reactive oxygen and nitrogen species (RONS) promote corticosteroid insensitivity by disrupting glucocorticoid receptor (GR) signaling, leading to the sustained activation of pro-inflammatory pathways in immune and airway structural cells. Studies in asthma and COPD models suggest that corticosteroids need a balanced redox environment to be effective and to reduce airway inflammation. In this review, we discuss how oxidative stress contributes to corticosteroid insensitivity and the importance of optimizing endogenous antioxidant responses to enhance corticosteroid sensitivity. Future studies should aim to identify how antioxidant-based therapies can complement corticosteroids to reduce the need for prolonged high dose regimens in patients with severe asthma and COPD.

S-Carboxymethyl-l-cysteine: a multiple dosing study using pharmacokinetic modelling

S-Carboxymethyl-l-cysteine is a mucolytic agent used as adjunctive therapy in the treatment of respiratory disorders. Various mechanisms of action have been proposed but few studies have attempted to link the required in vitro concentrations with those achieved actually in vivo during clinical therapy.The data from several published studies has been re-analysed by WinNonlin using non-compartmental analysis modelling, Phoenix modelling and Classic PK compartmental modelling for both single (500-1500 mg) and multiple oral administration of the drug.Multiple dose modelling indicated maximum peak concentrations (C_max) ranging from 1.29 to 11.22 μg/ml and those at steady state (C_ss(av)) from 1.30 to 8.40 μg/ml. For the standard therapeutic regimen of 3 × 750 mg (2250 mg/day) these values were 1.29-5.22 μg/ml (C_max) and 1.30-3.50 μg/ml (C_ss(av)). No accumulation was observed.Hence, only the pharmacodynamic studies reporting significant effects below c.10 μg/ml were likely to occur in vivo and these were mainly gene-related mechanisms. The majority of events, although demonstrable in vitro, required levels much greater than possible to achieve in the clinical situation.Such unappreciated disregard for in vitro-in vivo 'concentration matching' may lead to erroneous conclusions regarding mechanisms of action for many drugs as well as for S-carboxymethyl-l-cysteine.

Loading of Beclomethasone in Liposomes and Hyalurosomes Improved with Mucin as Effective Approach to Counteract the Oxidative Stress Generated by Cigarette Smoke Extract

In this work beclomethasone dipropionate was loaded into liposomes and hyalurosomes modified with mucin to improve the ability of the payload to counteract the oxidative stress and involved damages caused by cigarette smoke in the airway. The vesicles were prepared by dispersing all components in the appropriate vehicle and sonicating them, thus avoiding the use of organic solvents. Unilamellar and bilamellar vesicles small in size (~117 nm), homogeneously dispersed (polydispersity index lower than 0.22) and negatively charged (~−11 mV), were obtained. Moreover, these vesicle dispersions were stable for five months at room temperature (~25 °C). In vitro studies performed using the Next Generation Impactor confirmed the suitability of the formulations to be nebulized as they were capable of reaching the last stages of the impactor that mimic the deeper airways, thus improving the deposition of beclomethasone in the target site. Further, biocompatibility studies performed by using 16HBE bronchial epithelial cells confirmed the high biocompatibility and safety of all the vesicles. Among the tested formulations, only mucin-hyalurosomes were capable of effectively counteracting the production of reactive oxygen species (ROS) induced by cigarette smoke extract, suggesting that this formulation may represent a promising tool to reduce the damaging effects of cigarette smoke in the lung tissues, thus reducing the pathogenesis of cigarette smoke-associated diseases such as chronic obstructive pulmonary disease, emphysema, and cancer.

Cigarette smoke and glutathione: Focus on in vitro cell models

Cigarette smoke (CS) is one of the most important preventable risk factors for the development of respiratory diseases, cardiovascular diseases, stroke, and various types of cancer. Due to its high intracellular concentration and central role in maintaining the cellular redox state, glutathione (GSH) is one of the key players in several enzymatic and non-enzymatic reactions necessary for protecting cells against CS-induced oxidative stress. A plethora of in vitro cell models have been used over the years to assess the effects of CS on intracellular GSH and its disulphide forms, i.e. glutathione disulphide (GSSG) and S-glutathionylated proteins. In this review, we described the effects of cell exposure to CS on cellular GSH and formation of its oxidized forms and adducts (GSH-conjugates). We also discussed the limitations and relevance of in vitro cell models of exposure to CS and critically assessed the congruence between smokers and in vitro cell models. What emerges clearly is that results obtained in vitro should be interpreted with extreme caution, bearing in mind the limitations of the specific cell model used. Despite this, in vitro cell models remain important tools in the assessment of CS-induced oxidative damage.

Alantolactone suppresses inflammation, apoptosis and oxidative stress in cigarette smoke-induced human bronchial epithelial cells through activation of Nrf2/HO-1 and inhibition of the NF-κB pathways

BACKGROUND

It is well established that airway remodeling and inflammation are characteristics for chronic obstructive pulmonary disease (COPD). Moreover, cigarette smoke extract (CSE) promots inflammation, apoptosis and oxidative stress in COPD. And, there is evidence suggested that alantolactone (ALT), a sesquiterpene lactone isolated from Inula helenium, plays an adverse role in inflammation, apoptosis and oxidative stress. However, few studies have investigated the function and mechanism of ALT treatment on the COPD pathological process.

METHODS

The levels of IL-1 β, TNF-α, IL-6 and IFN-γ were examined by ELISA. Cells' apoptosis and caspase-3 activity were detected by Cell Death Detection PLUS enzyme-linked immunosorbent assay and caspase-Glo 3/7 Assay, respectively. The content of malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by using MDA and SOD assay kits. Reactive oxygen species (ROS) generation was measured by DCFH-DA assay. Protein expression was assayed by Western blot.

RESULTS

In the present study, we aimed to observe the protective effects of ALT against inflammation, apoptosis and oxidative stress in human bronchial epithelial Beas-2B and NHBE cells. Our results showed that different doses of CSE exposure induced Beas-2B and NHBE cell inflammatory cytokines IL-1 β, TNF-α, IL-6 and IFN-γ expression, cell apoptosis, caspase-3 activity and mediated oxidative stress markers MDA, ROS and SOD levels, while ALT treatment counteracted the effects of CSE. Further studies suggested that ALT attenuated NF-κB pathway activation. ALT also activated the Nrf2/HO-1 signal pathway through promoting Nrf2 nuclear aggregation and downstream HO-1 protein expression. HO-1 inhibitor tin protoporphyrin IX (SnPP IX) reversed the effects of ALT on Beas-2B and NHBE cell inflammation, apoptosis and oxidative stress.

CONCLUSIONS

The above results collectively suggested that ALT suppressed CSE-induced inflammation, apoptosis and oxidative stress by modulating the NF-ĸB and Nrf2/ HO-1 axis.

Cigarette smoke extract modulates E-Cadherin, Claudin-1 and miR-21 and promotes cancer invasiveness in human colorectal adenocarcinoma cells

BACKGROUND

Cigarette smoke is considered a risk factor for lung and colorectal cancer. A convincing link between epithelial-to-mesenchymal transition (EMT) with colorectal cancer progression and therapeutic resistance has emerged. Deregulated expression of E-Cadherin and Claudin-1 and increased miR-21 expression and invasiveness represent hallmarks of EMT. The effects of cigarette smoke exposure on EMT in colorectal adenocarcinoma cells are largely unknown.

AIM

The aim of the study is to evaluate the effect of cigarette smoke extract (CSE) on miR-21, Claudin-1 and E-Cadherin, molecules associated to EMT in colorectal cancer cells.

METHODS

A human colorectal adenocarcinoma cell line (Caco-2) was treated with CSE at different concentration (5% and 10%) and for different time points (3 h and 24 h). Metabolic activity (by MTS assay), cell necrosis/cell apoptosis (evaluating Propidium Iodide/Annexin V expression by flow cytometry), miR-21, Claudin-1 and E-Cadherin gene expression were evaluated by Real time PCR. Cell permeability, actin polymerization and cancer cell migration was assessed by Trans-Epitelial Electrical Resistance (TEER), Phalloidin expression and matrigel system, respectively.

RESULTS

CSE at all the tested concentrations and at all time points reduced cell necrosis. CSE at 10% increased miR-21 and reduced the metabolic activity, cell necrosis, Claudin-1 and E-cadherin mRNA at 3 h. Cell permeability, actin polymerization and cancer cell migration were all increased upon CSE exposure.

CONCLUSION

These results showed that CSE increasing miR-21, Claudin-1 and E-Cadherin and enhancing the aggressiveness of cancer cells, may concur to colorectal cancer progression.

Protein carbonylation in human bronchial epithelial cells exposed to cigarette smoke extract

Cigarette smoke is a well-established exogenous risk factor containing toxic reactive molecules able to induce oxidative stress, which in turn contributes to smoking-related diseases, including cardiovascular, pulmonary, and oral cavity diseases. We investigated the effects of cigarette smoke extract on human bronchial epithelial cells. Cells were exposed to various concentrations (2.5-5-10-20%) of cigarette smoke extract for 1, 3, and 24 h. Carbonylation was assessed by 2,4-dinitrophenylhydrazine using both immunocytochemical and Western immunoblotting assays. Cigarette smoke induced increasing protein carbonylation in a concentration-dependent manner. The main carbonylated proteins were identified by means of two-dimensional electrophoresis coupled to MALDI-TOF mass spectrometry analysis and database search (redox proteomics). We demonstrated that exposure of bronchial cells to cigarette smoke extract induces carbonylation of a large number of proteins distributed throughout the cell. Proteins undergoing carbonylation are involved in primary metabolic processes, such as protein and lipid metabolism and metabolite and energy production as well as in fundamental cellular processes, such as cell cycle and chromosome segregation, thus confirming that reactive carbonyl species contained in cigarette smoke markedly alter cell homeostasis and functions.

MiR-21 upregulation increases IL-8 expression and tumorigenesis program in airway epithelial cells exposed to cigarette smoke

BACKGROUND

Cigarette smoke exposure, increasing Toll-like receptor 4 (TLR4) and reactive oxygen species (ROS), promotes inflammatory responses in airway epithelial cells. Chronic inflammation, microRNA (miRNA), and oxidative stress are associated with cancer development.

AIMS

The present study was aimed to explore whether cigarette smoke exposure, altering miR-21 expression, promoted inflammatory responses and tumorigenesis processes in airway epithelial cells.

METHODS

Airway normal and cancer epithelial cells (16HBE and A549) were exposed to cigarette smoke extracts (CSE) or with/without agomiR-21, and then it was assessed: a) miR-21 expression; b) signal transducer and activator of transcription 3 (STAT3) nuclear protein expression and ERK1/2 activation; c) IL-8 gene expression and protein release. An antagonist of TLR4 (CLI-095) and the antioxidant flavonoid, apigenin, were also included to evaluate miR-21 expression in CSE exposed cells.

RESULTS

It was demonstrated that: a) A549 cells constitutively expressed higher levels of miR-21 and IL-8; b) CSE increased STAT3 nuclear expression in 16HBE; c) in both cell lines, CSE and agomiR-21 increased: miR-21 expression; ERK1/2 activation and IL-8 gene expression and protein release; d) TLR4 inhibition counteracted the effects of CSE on miR-21 in A549; e) apigenin reduced miR-21 and IL-8 gene expression in both cell lines.

CONCLUSIONS

Data herein provided identified for the first time new mechanisms supporting the crucial role of cigarette smoke-induced miR-21 expression in the amplification of inflammatory responses and in tumorigenesis processes within the airways.

Budesonide, Aclidinium and Formoterol in combination limit inflammaging processes in bronchial epithelial cells exposed to cigarette smoke

Inflammation and cellular senescence (also called inflammaging) are involved in the pathogenesis of premature lung aging, a key driver of chronic obstructive pulmonary disease (COPD). Downregulation of histone deacetylases and FoxO3 expression, activation of the ERK 1/2 pathway and IL-8 increase are hallmarks of lung inflammaging. The effects of Budesonide (BUD), Aclidinium (ACL) and Formoterol (FO) on lung inflammaging are unknown. This study was aimed to assess the effects of BUD, ACL and FO in bronchial epithelial cells exposed to cigarette smoke extract (CSE) by evaluating: a) Expression of TLR4 and survivin and LPS binding by flow cytometry; b) expression of HDAC2, HDAC3, SIRT1 and FoxO3 and activation of the ERK 1/2 pathway by western blot; c) IL-8 mRNA levels and release by Real Time-PCR and ELISA, respectively. Reported results show that CSE increased TLR4 and survivin, LPS binding, ERK 1/2 activation, IL-8 release and mRNA levels but decreased SIRT1, HDAC2, HDAC3 and FoxO3 nuclear expression. Combined therapy with BUD, ACL and FO counteracted the effects of CSE on LPS binding, FoxO3 nuclear expression, ERK 1/2 activation, survivin and IL-8 release and mRNA levels. These findings suggest a new role of combination therapy with BUD, ACL and FO in counteracting inflammaging processes induced by cigarette smoke exposure.

HDAC2 attenuates airway inflammation by suppressing IL-17A production in HDM-challenged mice

Histone deacetylase (HDAC)2 is expressed in airway epithelium and plays a pivotal role in inflammatory cells. However, the role of HDAC2 in allergic airway inflammation remains poorly understood. In the present study, we determined the role of HDAC2 in airway inflammation using in vivo models of house dust mite (HDM)-induced allergic inflammation and in vitro cultures of human bronchial epithelial (HBE) cells exposed to HDM, IL-17A, or both. We observed that HDM-challenged Hdac2^+/- mice exhibited substantially enhanced infiltration of inflammatory cells. Higher levels of T helper 2 cytokines and IL-17A expression were found in lung tissues of HDM-challenged Hdac2^+/- mice. Interestingly, IL-17A deletion or anti-IL-17A treatment reversed the enhanced airway inflammation induced by HDAC2 impairment. In vitro, HDM and IL-17A synergistically decreased HDAC2 expression in HBE cells. HDAC2 gene silencing further enhanced HDM- and/or IL-17A-induced inflammatory cytokines in HBE cells. HDAC2 overexpresion or blocking IL-17A gene expression restored the enhanced inflammatory cytokines. Collectively, these results support a protective role of HDAC2 in HDM-induced airway inflammation by suppressing IL-17A production and might suggest that activation of HDAC2 and/or inhibition of IL-17A production could prevent the development of allergic airway inflammation.

Cigarette smoke promotes HIV infection of primary bronchial epithelium and additively suppresses CFTR function

Recurrent lung infections are a common cause of morbidity and mortality in people living with HIV and this is exacerbated in smokers even when administered combination antiretroviral therapy (cART). The incidence of pneumonia is increased with smoking and treatment interruption and is directly dependent on viral load in patients when adjusted for CD4 counts. CFTR dysfunction plays an important role in aberrant airway innate immunity as it is pivotal in regulating mucociliary clearance (MCC) rates and other antibacterial mechanisms of the airway. In our earlier work, we have demonstrated that bronchial epithelium expresses canonical HIV receptors CD4, CCR5 and CXCR4 and can be infected with HIV. HIV Tat suppresses CFTR mRNA and function via TGF-β signaling. In the present study, we demonstrate that cigarette smoke (CS) potentiates HIV infection of bronchial epithelial cells by upregulating CD4 and CCR5 expression. HIV and CS individually and additively suppress CFTR biogenesis and function, possibly explaining the increased incidence of lung infections in HIV patients and its exacerbation in HIV smokers.

SIRT1/FoxO3 axis alteration leads to aberrant immune responses in bronchial epithelial cells

Inflammation and ageing are intertwined in chronic obstructive pulmonary disease (COPD). The histone deacetylase SIRT1 and the related activation of FoxO3 protect from ageing and regulate inflammation. The role of SIRT1/FoxO3 in COPD is largely unknown. This study evaluated whether cigarette smoke, by modulating the SIRT1/FoxO3 axis, affects airway epithelial pro-inflammatory responses. Human bronchial epithelial cells (16HBE) and primary bronchial epithelial cells (PBECs) from COPD patients and controls were treated with/without cigarette smoke extract (CSE), Sirtinol or FoxO3 siRNA. SIRT1, FoxO3 and NF-κB nuclear accumulation, SIRT1 deacetylase activity, IL-8 and CCL20 expression/release and the release of 12 cytokines, neutrophil and lymphocyte chemotaxis were assessed. In PBECs, the constitutive FoxO3 expression was lower in patients with COPD than in controls. Furthermore, CSE reduced FoxO3 expression only in PBECs from controls. In 16HBE, CSE decreased SIRT1 activity and nuclear expression, enhanced NF-κB binding to the IL-8 gene promoter thus increasing IL-8 expression, decreased CCL20 expression, increased the neutrophil chemotaxis and decreased lymphocyte chemotaxis. Similarly, SIRT1 inhibition reduced FoxO3 expression and increased nuclear NF-κB. FoxO3 siRNA treatment increased IL-8 and decreased CCL20 expression in 16HBE. In conclusion, CSE impairs the function of SIRT1/FoxO3 axis in bronchial epithelium, dysregulating NF-κB activity and inducing pro-inflammatory responses.

Polyaspartamide-Based Nanoparticles Loaded with Fluticasone Propionate and the In Vitro Evaluation towards Cigarette Smoke Effects

This paper describes the evaluation of polymeric nanoparticles (NPs) as a potential carrier for lung administration of fluticasone propionate (FP). The chosen polymeric material to produce NPs was a copolymer based on α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) whose backbone was derivatised with different molecules, such as poly(lactic acid) (PLA) and polyethylenglycol (PEG). The chosen method to produce NPs from PHEA-PLA-PEG₂₀₀₀ was the method based on high-pressure homogenization and subsequent solvent evaporation by adding Pluronic F68 during the process and trehalose before lyophilisation. Obtained colloidal FP-loaded NPs showed a slightly negative surface charge and nanometric dimensions that are maintained after storage for one year at −20 °C and 5 °C. The FP loading was about 2.9 wt % and the drug was slowly released in simulated lung fluid. Moreover, the obtained NPs, containing the drug or not, were biocompatible and did not induce cell necrosis and cell apoptosis on bronchial epithelial cells (16-HBE). Further in vitro testing on cigarette smoke extract (CSE)-stimulated 16-HBE revealed that FP-loaded NPs were able to reduce the survivin expression, while either free FP or empty NPs were not able to significantly reduce this effect.

Response of turkey muscle satellite cells to thermal challenge. I. transcriptome effects in proliferating cells

BACKGROUND

Climate change poses a multi-dimensional threat to food and agricultural systems as a result of increased risk to animal growth, development, health, and food product quality. This study was designed to characterize transcriptional changes induced in turkey muscle satellite cells cultured under cold or hot thermal challenge to better define molecular mechanisms by which thermal stress alters breast muscle ultrastructure.

RESULTS

Satellite cells isolated from the pectoralis major muscle of 7-weeks-old male turkeys from two breeding lines (16 weeks body weight-selected and it's randombred control) were proliferated in culture at 33 °C, 38 °C or 43 °C for 72 h. Total RNA was isolated and 12 libraries subjected to RNAseq analysis. Statistically significant differences in gene expression were observed among treatments and between turkey lines with a greater number of genes altered by cold treatment than by hot and fewer differences observed between lines than between temperatures. Pathway analysis found that cold treatment resulted in an overrepresentation of genes involved in cell signaling/signal transduction and cell communication/cell signaling as compared to control (38 °C). Heat-treated muscle satellite cells showed greater tendency towards expression of genes related to muscle system development and differentiation.

CONCLUSIONS

This study demonstrates significant transcriptome effects on turkey skeletal muscle satellite cells exposed to thermal challenge. Additional effects on gene expression could be attributed to genetic selection for 16 weeks body weight (muscle mass). New targets are identified for further research on the differential control of satellite cell proliferation in poultry.

Formoterol and fluticasone propionate combination improves histone deacetylation and anti-inflammatory activities in bronchial epithelial cells exposed to cigarette smoke

BACKGROUND

The addition of long-acting beta2-agonists (LABAs) to corticosteroids improves asthma control. Cigarette smoke exposure, increasing oxidative stress, may negatively affect corticosteroid responses. The anti-inflammatory effects of formoterol (FO) and fluticasone propionate (FP) in human bronchial epithelial cells exposed to cigarette smoke extracts (CSE) are unknown.

AIMS

This study explored whether FP, alone and in combination with FO, in human bronchial epithelial cellline (16-HBE) and primary bronchial epithelial cells (NHBE), counteracted some CSE-mediated effects and in particular some of the molecular mechanisms of corticosteroid resistance.

METHODS

16-HBE and NHBE were stimulated with CSE, FP and FO alone or combined. HDAC3 and HDAC2 activity, nuclear translocation of GR and NF-κB, pERK1/2/tERK1/2 ratio, IL-8, TNF-α, IL-1β mRNA expression, and mitochondrial ROS were evaluated. Actin reorganization in neutrophils was assessed by fluorescence microscopy using the phalloidin method.

RESULTS

In 16-HBE, CSE decreased expression/activity of HDAC3, activity of HDAC2, nuclear translocation of GR and increased nuclear NF-κB expression, pERK 1/2/tERK1/2 ratio, and mRNA expression of inflammatory cytokines. In NHBE, CSE increased mRNA expression of inflammatory cytokines and supernatants from CSE exposed NHBE increased actin reorganization in neutrophils. FP combined with FO reverted all these phenomena in CSE stimulated 16-HBE cells as well as in NHBE cells.

CONCLUSIONS

The present study provides compelling evidences that FP combined with FO may contribute to revert some processes related to steroid resistance induced by oxidative stress due to cigarette smoke exposure increasing the anti-inflammatory effects of FP.

Carbocysteine counteracts the effects of cigarette smoke on cell growth and on the SIRT1/FoxO3 axis in bronchial epithelial cells

BACKGROUND

Cigarette smoke may accelerate cellular senescence by increasing oxidative stress. Altered proliferation and altered expression of anti-aging factors, including SIRT1 and FoxO3, characterise cellular senescence. The effects of carbocysteine on the SIRT1/FoxO3 axis and on downstream molecular mechanisms in human bronchial epithelial cells exposed to cigarette smoke are largely unknown.

AIMS

Aim of this study was to explore whether carbocysteine modulated SIRT1/FoxO3 axis, and downstream molecular mechanisms associated to cellular senescence, in a bronchial epithelial cell line (16-HBE) exposed to cigarette smoke.

METHODS

16HBE cells were stimulated with/without cigarette smoke extracts (CSE) and carbocysteine. Flow cytometry and clonogenic assay were used to assess cell proliferation; western blot analysis was used for assessing nuclear expression of SIRT1 and FoxO3. The nuclear co-localization of SIRT1 and FoxO3 was assessed by fluorescence microscopy. Beta galactosidase (a senescence marker) and SIRT1 activity were assessed by specific staining and colorimetric assays, respectively. ChiP Assay and flow cytometry were used for assessing survivin gene regulation and protein expression, respectively.

RESULTS

CSE decreased cell proliferation, the nuclear expression of SIRT1 and FoxO3 and increased beta galactosidase staining. CSE, reduced SIRT1 activity and FoxO3 localization on survivin promoter thus increasing survivin expression. In CSE stimulated bronchial epithelial cells carbocysteine reverted these phenomena by increasing cell proliferation, and SIRT1 and FoxO3 nuclear expression, and by reducing beta galactosidase staining and survivin expression.

CONCLUSIONS

The study shows for the first time that carbocysteine may revert some senescence processes induced by oxidative stress due to cigarette smoke exposure.

Carbocisteine attenuates TNF-α-induced inflammation in human alveolar epithelial cells in vitro through suppressing NF-κB and ERK1/2 MAPK signaling pathways

AIM

We previously proven that carbocisteine, a conventional mucolytic drug, remarkably reduced the rate of acute exacerbations and improved the quality of life in the patients with chronic obstructive pulmonary disease. In this study we investigated the mechanisms underlying the anti-inflammatory effects of carbocisteine in human alveolar epithelial cells in vitro.

METHODS

Human lung adenocarcinoma cell line A549 was treated with TNF-α (10 ng/mL). Carbocisteine was administered either 24 h prior to or after TNF-α exposure. The cytokine release and expression were measured using ELISA and qRT-PCR. Activation of NF-κB was analyzed with Western blotting, immunofluorescence assay and luciferase reporter gene assay. The expression of ERK1/2 MAPK signaling proteins was assessed with Western blotting.

RESULTS

Carbocisteine (10, 100, 1000 μmol/L), administered either before or after TNF-α exposure, dose-dependently suppressed TNF-α-induced inflammation in A549 cells, as evidenced by diminished release of IL-6 and IL-8, and diminished mRNA expression of IL-6, IL-8, TNF-α, MCP-1 and MIP-1β. Furthermore, pretreatment with carbocisteine significantly decreased TNF-α-induced phosphorylation of NF-κB p65 and ERK1/2 MAPK, and inhibited the nuclear translocation of p65 subunit in A549 cells. In an NF-κB luciferase reporter system, pretreatment with carbocisteine dose-dependently inhibited TNF-α-induced transcriptional activity of NF-κB.

CONCLUSION

Carbocisteine effectively suppresses TNF-α-induced inflammation in A549 cells via suppressing NF-κB and ERK1/2 MAPK signaling pathways.

Carbocysteine restores steroid sensitivity by targeting histone deacetylase 2 in a thiol/GSH-dependent manner

Steroid insensitivity is commonly observed in patients with chronic obstructive pulmonary disease. Here, we report the effects and mechanisms of carbocysteine (S-CMC), a mucolytic agent, in cellular and animal models of oxidative stress-mediated steroid insensitivity. The following results were obtained: oxidative stress induced higher levels of interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α), which are insensitive to dexamethasone (DEX). The failure of DEX was improved by the addition of S-CMC by increasing histone deacetylase 2 (HDAC2) expression/activity. S-CMC also counteracted the oxidative stress-induced increase in reactive oxygen species (ROS) levels and decreases in glutathione (GSH) levels and superoxide dismutase (SOD) activity. Moreover, oxidative stress-induced events were decreased by the thiol-reducing agent dithiothreitol (DTT), enhanced by the thiol-oxidizing agent diamide, and the ability of DEX was strengthened by DTT. In addition, the oxidative stress-induced decrease in HDAC2 activity was counteracted by S-CMC by increasing thiol/GSH levels, which exhibited a direct interaction with HDAC2. S-CMC treatment increased HDAC2 recruitment and suppressed H4 acetylation of the IL-8 promoter, and this effect was further ablated by addition of buthionine sulfoximine, a specific inhibitor of GSH synthesis. Our results indicate that S-CMC restored steroid sensitivity by increasing HDAC2 expression/activity in a thiol/GSH-dependent manner and suggest that S-CMC may be useful in a combination therapy with glucocorticoids for treatment of steroid-insensitive pulmonary diseases.

Carbocisteine attenuates hydrogen peroxide-induced inflammatory injury in A549 cells via NF-κB and ERK1/2 MAPK pathways

Carbocisteine is a mucolytic drug with anti-oxidative effect, we had previously proved that carbocisteine remarkably reduced the rate of acute exacerbations and improved the quality of life in patients with chronic obstructive pulmonary disease (COPD), however, very little is known about its mechanisms. In this study, we aimed to investigate the anti-inflammatory effects of carbocisteine against hydrogen peroxide (H2O2). A549 cells were cultured in vitro and treated with H2O2 as damaged cell models, carbocisteine was administered 24h prior to or after H2O2 exposure, and the protective effects of carbocisteine were determined by MTT, qRT-PCR, ELISA, western blot and immunofluorescence assays. The results showed that carbocisteine could increase cell viability and decrease LDH, IL-6 and IL-8 levels in the supernatant. Additionally, carbocisteine decreased IL-6, IL-8, TNF-α, IP-10 and MIP-1β mRNA in a dose-dependent manner. Moreover, carbocisteine could attenuate phosphorylation of NF-κB p65 and ERK1/2 and inhibit the nuclear translocation of pNF-κB p65 induced by H2O2. In conclusion, carbocisteine inhibited H2O2-induced inflammatory injury in A549 cells, NF-κB and ERK1/2 MAPK were the target pathways.

Effects in cigarette smoke stimulated bronchial epithelial cells of a corticosteroid entrapped into nanostructured lipid carriers

BACKGROUND

Nanomedicine studies have showed a great potential for drug delivery into the lung. In this manuscript nanostructured lipid carriers (NLC) containing Fluticasone propionate (FP) were prepared and their biocompatibility and effects in a human bronchial epithelial cell line (16-HBE) stimulated with cigarette smoke extracts (CSE) were tested.

RESULTS

Biocompatibility studies showed that the NLC did not induce cell necrosis or apoptosis. Moreover, it was confirmed that CSE increased intracellular ROS production and TLR4 expression in bronchial epithelial cells and that FP-loaded NLC were more effective than free drug in modulating these processes. Finally, the nanoparticles increased GSH levels improving cell protection against oxidative stress.

CONCLUSIONS

The present study shows that NLC may be considered a promising strategy to improve corticosteroid mediated effects in cellular models associated to corticosteroid resistance. The NLC containing FP can be considered good systems for dosage forms useful for increasing the effectiveness of fluticasone decreasing its side effects.

Alterations of bronchial epithelial metabolome by cigarette smoke are reversible by an antioxidant, O-methyl-L-tyrosinyl-γ-L-glutamyl-L-cysteinylglycine

Human bronchial epithelial cells (HBECs) have first-line contact with harmful substances during smoking, and changes in their metabolism most likely represent a defining factor in coping with the stress and development of airway diseases. This study was designed to determine the dynamics of metabolome changes in HBECs treated with cigarette smoke condensate (CSC), and to test whether normal metabolism can be restored by synthetic antioxidants. Principal component analysis, based on untargeted mass spectra, indicated that treatment of CSC-exposed HBECs with O-methyl-L-tyrosinyl-γ-L-glutamyl-L-cysteinylglycine (UPF1) acted faster than did N-acetylcysteine to revert the effect of CSC. The maximum effect of 10 μg/ml CSC itself on HBEC cell line, BEAS-2B, metabolism was seen at 2 hours after treatment, with return to the baseline level by 7 hours. In primary HBECs, the initial maximum effect was seen at 1 hour after CSC exposure. Certain metabolites associated with redox pathways and energy production were affected by CSC. Subsequent restoration of their content by UPF1 supports the hypothetical protective capacity of UPF1 against the oxidative stress and increased energy demand, respectively. Furthermore, UPF1 up-regulated the contents of phospholipid species identified as phosphatidylcholines and phosphatidylethanolamines in the CSC-exposed HBECs, indicating possible suppression of inflammatory processes along with an increase in spermidine as an endogenous cytoprotector. In conclusion, with this dynamic metabolomics study, we characterize the durability of the CSC-induced metabolic changes in BEAS-2B line cells and primary HBECs, and demonstrate the ability of UPF1 to significantly accelerate the recovery of HBECs from CSC insult.

Downregulation of ribosomal protein S6 inhibits the growth of non-small cell lung cancer by inducing cell cycle arrest, rather than apoptosis

Ribosomal protein S6 (rpS6), a component of the small 40S ribosomal subunit, has been found to be associated with multiple physiological and pathophysiological functions. However, its effects and mechanisms in non-small cell lung cancer (NSCLC) still remain unknown. Here, we showed that expressions of total rpS6 and phosphorylation rpS6 (p-rpS6) were both significantly overexpressed in NSCLC. Further survival analysis revealed the shortened overall survival (OS) and relapse-free survival (RFS) in p-rpS6 overexpressed patients and confirmed it as an independent adverse predictor. Stable downregulation of rpS6 in lung adenocarcinoma A549 and squamous cell carcinoma H520 cell lines was then achieved by two specific small hairpin RNA (shRNA) lentiviruses separately. Subsequent experiments showed that downregulation of rpS6 dramatically inhibited cell proliferation in vitro and tumorigenicity in vivo. Moreover, loss of rpS6 promoted cells arrested in G0-G1 phase and reduced in G2-M phase, along with the expression alterations of relative proteins. However, no notable change in apoptosis was observed. Collectively, these results suggested that rpS6 is overactivated in NSCLC and its downregulation suppresses the growth of NSCLC mainly by inducing G0-G1 cell cycle arrest rather than apoptosis.

Oxidative stress and innate immunity responses in cigarette smoke stimulated nasal epithelial cells

Cigarette smoke extracts (CSE) may play a significant role in diseases of the upper airway including chronic rhinosinusitis. Even short term exposure of cigarette smoke has adverse effects on mitochondrial functions and redox homeostasis in tissues which may progress to further complications associated with chronic smoking. Cigarette smoke alters toll-like receptor 4 (TLR4) expression and activation in bronchial epithelial cells. Carbocysteine is an anti-oxidant and mucolytic agent. The effects of carbocysteine on CSE induced oxidative stress and on associated innate immune and inflammatory responses in nasal epithelial cells are largely unknown. The present study was aimed to assess in CSE stimulated nasal epithelial cells (RPMI 2650) the effects of carbocysteine (10(-4)M) on: cell survival, intracellular reactive oxygen species (ROS) production, TLR4 expression, LPS binding and neutrophil chemotaxis (actin reorganization). We found that CSE increased ROS production, TLR4 expression, LPS binding and neutrophil chemotaxis and all these events were counteracted by pre-incubating CSE stimulated RPMI 2650 cells with carbocysteine. In conclusion, the present study provides compelling evidence that carbocysteine may be considered a promising therapeutic strategy in chronic inflammatory nasal diseases.

Roflumilast N-oxide inhibits bronchial epithelial to mesenchymal transition induced by cigarette smoke in smokers with COPD

BACKGROUND

Epithelial to mesenchymal transition (EMT) is under discussion as a potential mechanism of small airway remodelling in COPD. In bronchial epithelium of COPD and smokers markers of EMT were described. In vitro, EMT may be reproduced by exposing well-differentiated human bronchial epithelial cells (WD-HBEC) to cigarette smoke extract (CSE). EMT may be mitigated by an increase in cellular cAMP.

OBJECTIVE

This study explored the effects of roflumilast N-oxide, a PDE4 inhibitor on CSE-induced EMT in WD-HBEC and in primary bronchial epithelial cells from smokers and COPD in vitro.

METHODS

WD-HBEC from normal donors were stimulated with CSE (2.5%) for 72 h in presence of roflumilast N-oxide (2 nM or 1 μM) or vehicle. mRNA and protein of EMT markers αSMA, vimentin, collagen-1, E-cadherin, ZO-1, KRT5 as well as NOX4 were quantified by real-time quantitative PCR or protein array, respectively. Phosphorylated and total ERK1/2 and Smad3 were assessed by protein array. cAMP and TGFβ1 were measured by ELISA. Reactive oxygen species (ROS) were determined by DCF fluorescence, after 30 min CSE (2.5%). Apoptosis was measured with Annexin V/PI labelling. In some experiments, EMT markers were determined in monolayers of bronchial epithelial cells from smokers, COPD versus controls.

RESULTS

Roflumilast N-oxide protected from CSE-induced EMT in WD-HBEC. The PDE4 inhibitor reversed both the increase in mesenchymal and the loss in epithelial EMT markers. Roflumilast N-oxide restored the loss in cellular cAMP following CSE, reduced ROS, NOX4 expression, the increase in TGFβ1 release, phospho ERK1/2 and Smad3. The PDE4 inhibitor partly protected from the increment in apoptosis with CSE. Finally the PDE4 inhibitor decreased mesenchymal yet increased epithelial phenotype markers in HBEC of COPD and smokers.

CONCLUSIONS

Roflumilast N-oxide may mitigate epithelial-mesenchymal transition in bronchial epithelial cells in vitro.

Carbocysteine regulates innate immune responses and senescence processes in cigarette smoke stimulated bronchial epithelial cells

Cigarette smoke represents the major risk factor for chronic obstructive pulmonary disease (COPD). Cigarette smoke extracts (CSE) alter TLR4 expression and activation in bronchial epithelial cells. Carbocysteine, an anti-oxidant and mucolytic agent, is effective in reducing the severity and the rate of exacerbations in COPD patients. The effects of carbocysteine on TLR4 expression and on the TLR4 activation downstream events are largely unknown. This study was aimed to explore whether carbocysteine, in a human bronchial epithelial cell line (16-HBE), counteracted some pro-inflammatory CSE-mediated effects. In particular, TLR4 expression, LPS binding, p21 (a senescence marker), IL-8 mRNA and release in CSE-stimulated 16-HBE as well as actin reorganization in neutrophils cultured with supernatants from bronchial epithelial cells which were stimulated with CSE and/or carbocysteine were assessed. TLR4 expression, LPS binding, and p21 expression were assessed by flow cytometry, IL-8 mRNA by Real Time PCR and IL-8 release by ELISA. Actin reorganization, a prerequisite for cell migration, was determined using Atto 488 phalloidin in neutrophils by flow cytometry and fluorescence microscopy. CSE increased: (1) TLR4, LPS binding and p21 expression; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil migration. Carbocysteine in CSE stimulated bronchial epithelial cells, reduced: (1) TLR4, LPS binding and p21; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil chemotactic migration. In conclusion, the present study provides compelling evidences that carbocysteine may contribute to control the inflammatory and senescence processes present in smokers.