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

Tyndallized bacteria prime bronchial epithelial cells to mount an effective innate immune response against infections

Airway epithelium represents a physical barrier against toxic substances and pathogens but also presents pattern recognition receptors on the epithelial cells that detect pathogens leading to molecule release and sending signals that activate both the innate and adaptive immune responses. Thus, impaired airway epithelial function and poor integrity may increase the recurrence of infections. Probiotic use in respiratory diseases as adjuvant of traditional therapy is increasingly widespread. There is growing interest in the use of non-viable heat-killed bacteria, such as tyndallized bacteria (TB), due to safety concerns and to their immunomodulatory properties. This study explores in vitro the effects of a TB blend on the immune activation of airway epithelium. 16HBE bronchial epithelial cells were exposed to different concentrations of TB. Cell viability, TB internalization, TLR2 expression, IL-6, IL-8 and TGF-βl expression/release, E-cadherin expression and wound healing were assessed. We found that TB were tolerated, internalized, increased TLR2, E-cadherin expression, IL-6 release and wound healing but decreased both IL-8 and TGF-βl release. In conclusion, TB activate TLR2 pathway without inducing a relevant pro-inflammatory response and improve barrier function, leading to the concept that TB preserve epithelial homeostasis and could be used as strategy to prevent and to manage respiratory infection, exacerbations included.

Precision medicine for asthma treatment: Unlocking the potential of the epigenome and microbiome

Asthma is a leading worldwide biomedical concern. Patients can experience life-threatening worsening episodes (exacerbations) usually controlled by anti-inflammatory and bronchodilator drugs. However, substantial heterogeneity in treatment response exists, and a subset of patients with unresolved asthma carry the major burden of this disease. The study of the epigenome and microbiome might bridge the gap between human genetics and environmental exposure to partially explain the heterogeneity in drug response. This review aims to provide a critical examination of the existing literature on the microbiome and epigenetic studies examining associations with asthma treatments and drug response, highlight convergent pathways, address current challenges, and offer future perspectives. Current epigenetic and microbiome studies have shown the bilateral relationship between asthma pharmacologic interventions and the human epigenome and microbiome. These studies, focusing on corticosteroids and to a lesser extent on bronchodilators, azithromycin, immunotherapy, and mepolizumab, have improved the understanding of the molecular basis of treatment response and identified promising biomarkers for drug response prediction. Immune and inflammatory pathways (eg, IL-2, TNF-α, NF-κB, and C/EBPs) underlie microbiome-epigenetic associations with asthma treatment, representing potential therapeutic pathways to be targeted. A comprehensive evaluation of these omics biomarkers could significantly contribute to precision medicine and new therapeutic target discovery.

Expression of glucocorticoid receptor and HDACs in airway smooth muscle cells is associated with response to steroids in COPD

BACKGROUND

Steroid insensitivity in Chronic Obstructive Pulmonary Disease (COPD) presents a problem for controlling the chronic inflammation of the airways. The glucocorticoid receptor (GR) mediates the intracellular signaling of inhaled corticosteroids (ICS) by interacting with transcription factors and histone deacetylases (HDACs). The aim of this study was to assess if COPD patients' response to ICS in vivo, may be associated with the expression of GR, the complex of GR with transcription factors, and the expression of various HDACs in vitro.

METHODS

Primary airway smooth muscle cells (ASMC) were established from endobronchial biopsies obtained from patients with asthma (n = 10), patients with COPD (n = 10) and subjects that underwent diagnostic bronchoscopy without pathological findings and served as controls (n = 6). ASMC were also established from 18 COPD patients, 10 responders and 8 non-responders to ICS, who participated in the HISTORIC study, an investigator-initiated and driven clinical trial that proved the hypothesis that COPD patients with high ASMC in their endobronchial biopsies respond better to ICS than patients with low ASMC. Expression of GR and its isoforms GRα and GRβ and HDACs was investigated in primary ASMC in the absence or in the presence of dexamethasone (10- 8M) by western blotting. The complex formation of GR with transcription factors was assessed by co-immunoprecipitation.

RESULTS

Expression of GR and its isoform GRα but not GRβ was significantly reduced in ASMC from COPD patients as compared to controls. There were no significant differences in the expression of GR, GRα and GRβ between responders and non-responders to ICS. However, treatment with dexamethasone upregulated the expression of total GR (p = 0.004) and GRα (p = 0.005) after 30 min in responders but not in non-responders. Τhe formation of the complex GR-c-Jun was increased 60 min after treatment with dexamethasone only in responders who exhibited significantly lower expression of HDAC3 (p = 0.005) and HDAC5 (p < 0.0001) as compared to non-responders.

CONCLUSIONS

These data suggest that ASMC from COPD patients who do not respond to treatment with ICS, are characterized by reduced GR-c-Jun complex formation and increased expression of HDAC3 and HDAC5.

TRIAL REGISTRATION

ISRCTN11017699 (Registration date: 15/11/2016).

Recent Developments in the Role of Histone Acetylation in Asthma

BACKGROUND

Epigenetic modifications are known to mediate both beneficial and unfavorable effects of environmental exposures on the development and clinical course of asthma. On the molecular level, epigenetic mechanisms participate in multiple aspects of the emerging and ongoing asthma pathology.

SUMMARY

Studies performed in the last several years expand our knowledge on the role of histone acetylation, a classical epigenetic mark, in the regulation of (patho)physiological processes of diverse cells playing a central role in asthma, including those belonging to the immune system (e.g., CD4+ T cells, macrophages) and lung structure (e.g., airway epithelial cells, pulmonary fibroblasts). Those studies demonstrate a number of specific histone acetylation-associated mechanisms and pathways underlying pathological processes characteristic for asthma, as well as report their modification modalities.

KEY MESSAGES

Dietary modulation of histone acetylation levels in the immune system might protect against the development of asthma and other allergies. Interfering with the enzymes controlling the histone acetylation status of structural lung and (local) immune cells might provide future therapeutic options for asthmatics. Despite some methodological obstacles, analysis of the histone acetylation levels might improve asthma diagnostics.

Comparison of the effects of active and passive smoking of tobacco cigarettes, electronic nicotine delivery systems and tobacco heating products on the expression and secretion of oxidative stress and inflammatory response markers. A systematic review

OBJECTIVES

This work attempts to summarize current knowledge on the effects of active and passive smoking of cigarettes, electronic nicotine delivery systems and tobacco heating products on the expression and secretion of oxidative stress and inflammatory response mediators, and on their possible impact on chronic obstructive pulmonary disease development.

MATERIALS AND METHODS

The literature was searched by the terms: 'smoking', 'active smoking', 'passive smoking', 'main-stream smoke', 'side-stream smoke', 'secondhand smoke', 'cigarette' 'THP', 'tobacco heating product', 'ENDS', 'electronic nicotine delivery system', 'e-cigarette', 'electronic cigarette', oxidative stress', inflammatory response' and 'gene expression'.

RESULTS

Cigarette smoking (active and passive) induces oxidative stress and inflammatory response in the airways. We present the effect of active smoking of e-cigarettes (EC) and heat-not-burn (HnB) products on the increased expression and secretion of oxidative stress and inflammatory response markers. However, there is only a limited number of studies on the effect of their second-hand smoking, and those available mainly describe aerosol composition.

DISCUSSION

The literature provides data which confirm that active and passive cigarette smoking induces oxidative stress and inflammatory response in the airways and is a key risk factor of COPD development. Currently, there is a limited number of data about ENDS and THP active and passive smoking effects on the health of smokers and never-smokers. It is particularly important to assess the effect of such products during long-term use by never-smokers who choose them as the first type of cigarettes, and for never-smokers who are passively exposed to their aerosol.

Formoterol Exerts Anti-Cancer Effects Modulating Oxidative Stress and Epithelial-Mesenchymal Transition Processes in Cigarette Smoke Extract Exposed Lung Adenocarcinoma Cells

Lung cancer frequently affects patients with Chronic Obstructive Pulmonary Disease (COPD). Cigarette smoke (CS) fosters cancer progression by increasing oxidative stress and by modulating epithelial-mesenchymal transition (EMT) processes in cancer cells. Formoterol (FO), a long-acting β2-agonist widely used for the treatment of COPD, exerts antioxidant activities. This study explored in a lung adenocarcinoma cell line (A549) whether FO counteracted the effects of cigarette smoke extract (CSE) relative to oxidative stress, inflammation, EMT processes, and cell migration and proliferation. A549 was stimulated with CSE and FO, ROS were evaluated by flow-cytometry and by nanostructured electrochemical sensor, EMT markers were evaluated by flow-cytometry and Real-Time PCR, IL-8 was evaluated by ELISA, cell migration was assessed by scratch and phalloidin test, and cell proliferation was assessed by clonogenic assay. CSE significantly increased the production of ROS, IL-8 release, cell migration and proliferation, and SNAIL1 expression but significantly decreased E-cadherin expression. FO reverted all these phenomena in CSE-stimulated A549 cells. The present study provides intriguing evidence that FO may exert anti-cancer effects by reverting oxidative stress, inflammation, and EMT markers induced by CS. These findings must be validated in future clinical studies to support FO as a valuable add-on treatment for lung cancer management.

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.

Tyndallized Bacteria Preferentially Induce Human Macrophage M1 Polarization: An Effect Useful to Balance Allergic Immune Responses and to Control Infections

Macrophage polarization is a dynamic process through which macrophages acquire specific features whose extremes are represented by M1 and M2 polarization. Interleukin (IL)-6, IL-1β, IL-12 and IL-8 belong to M1 macrophages while transforming growth factor-beta (TGF-β belongs to M2 cytokines. M2 polarization prevalence is observed in allergic diseases. Tyndallization is a thermal process able to inactivate microorganisms and to allow their use for chronic respiratory disease treatment via immune response modulation. The present study explores the effects of a blend of tyndallized bacteria (TB) on macrophage polarization. THP-1-derived macrophages were exposed to different concentrations of TB (106, 5 × 106, 107, 5 × 107, 108 CFU/mL) and then cell viability and TB phagocytosis, and IL-8, IL-1β, IL-6, IL-12 and TGF-β1 gene expression and release were assessed. TB were tolerated, phagocyted and able to increase IL-8, IL-1β and IL-6 gene expression and release IL-12 gene expression, as well as decrease TGF-β1 gene expression and release. The effects on IL-8, IL-6 and TGF-β1 release were confirmed in human monocyte-derived macrophages (hMDMs) exposed to TB. In conclusion, TB promote M1 polarization, and this mechanism might have valuable potential in controlling allergic diseases and infections, possibly preventing disease exacerbations.

Bruton's tyrosine kinase inhibition suppresses neutrophilic inflammation and restores histone deacetylase 2 expression in myeloid and structural cells in a mixed granulocytic mouse model of asthma

Asthmatic inflammation is not a single homogenous inflammation but may be categorized into several phenotypes/endotypes. Severe asthma is characterized by mixed granulocytic inflammation in which there is increased presence of neutrophilic numbers and unresponsiveness to corticosteroids. Neutrophilic oxidative stress and histone deacetylase 2 (HDAC2) dysregulation in the pulmonary compartment are thought to lead to corticosteroid insensitivity in severe asthma with mixed granulocytic inflammation. Bruton's tyrosine kinase (BTK) is a no-receptor tyrosine kinase which is expressed in innate immune cells such as neutrophils and dendritic cells (DCs) where it is incriminated in balancing of inflammatory signaling. We hypothesized in this study that BTK inhibition strategy could be utilized to restore corticosteroid responsiveness in mixed granulocytic asthma. Therefore, combined therapy of BTK inhibitor (ibrutinib) and corticosteroid, dexamethasone was administered in cockroach allergen extract (CE)-induced mixed granulocyte airway inflammation model in mice. Our data show that CE-induced neutrophilic inflammation was concomitant with HDAC2 expression and upregulation of p-NFkB expression in airway epithelial cells (AECs), myeloid cells and pulmonary tissue. Further, there were increased expression/release of inflammatory and oxidative mediators such as MUC5AC, TNF-α, GM-CSF, MCP-1, iNOS, nitrotyrosine, MPO, lipid peroxides in AECs/myeloid cells/pulmonary tissue. Dexamethasone alone significantly attenuated eosinophilic inflammation and inflammatory cytokines but was not able to control oxidative inflammation. Ibrutinib alone markedly reduced neutrophilic infiltration and oxidative inflammation, and restored HDAC2 without having any significant effect on eosinophilic inflammation. These data suggest that BTK inhibition strategy may be used in conjunction with dexamethasone to treat both neutrophilic and eosinophilic inflammation, i.e. mixed granulocytic asthma.

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.

Electrochemical Quantification of H2O2 Released by Airway Cells Growing in Different Culture Media

Quantification of oxidative stress is a challenging task that can help in monitoring chronic inflammatory respiratory airway diseases. Different studies can be found in the literature regarding the development of electrochemical sensors for H2O2 in cell culture medium to quantify oxidative stress. However, there are very limited data regarding the impact of the cell culture medium on the electrochemical quantification of H2O2. In this work, we studied the effect of different media (RPMI, MEM, DMEM, Ham's F12 and BEGM/DMEM) on the electrochemical quantification of H2O2. The used electrode is based on reduced graphene oxide (rGO) and gold nanoparticles (AuNPs) and was obtained by co-electrodeposition. To reduce the electrode fouling by the medium, the effect of dilution was investigated using diluted (50% v/v in PBS) and undiluted media. With the same aim, two electrochemical techniques were employed, chronoamperometry (CH) and linear scan voltammetry (LSV). The influence of different interfering species and the effect of the operating temperature of 37 °C were also studied in order to simulate the operation of the sensor in the culture plate. The LSV technique made the sensor adaptable to undiluted media because the test time is short, compared with the CH technique, reducing the electrode fouling. The long-term stability of the sensors was also evaluated by testing different storage conditions. By storing the electrode at 4 °C, the sensor performance was not reduced for up to 21 days. The sensors were validated measuring H2O2 released by two different human bronchial epithelial cell lines (A549, 16HBE) and human primary bronchial epithelial cells (PBEC) grown in RPMI, MEM and BEGM/DMEM media. To confirm the results obtained with the sensor, the release of reactive oxygen species was also evaluated with a standard flow cytometry technique. The results obtained with the two techniques were very similar. Thus, the LSV technique permits using the proposed sensor for an effective oxidative stress quantification in different culture media and without dilution.

The Protective Anticancer Effect of Natural Lycopene Supercritical CO2 Watermelon Extracts in Adenocarcinoma Lung Cancer Cells

Carotenoids may have different effects on cancer and its progression. The safety of carotenoid supplements was evaluated in vitro on human non-small cell lung cancer (NSCLC) adenocarcinoma A549 cells by the administration of three different oleoresins containing lycopene and other lipophilic phytochemicals, such as tocochromanols. The oleoresins, obtained by the supercritical CO₂ green extraction technology from watermelon (Lyc W), gấc(Lyc G) and tomato (Lyc T) and chlatrated in α-cyclodextrins, were tested in comparison to synthetic lycopene (Lyc S), by cell cycle, Annexin V-FITC/PI, clonogenic test, Mytosox, intracellular ROS, Western Blot for NF-kB and RT-PCR and ELISA for IL-8. The extracts administered at the same lycopene concentration (10 µM) showed conflicting behaviors: Lyc W, with the highest lycopene/tocochromanols ratio, significantly increased cell apoptosis, mitochondrial stress, intracellular ROS, NF-kB and IL-8 expression and significantly decreased cell proliferation, whereas Lyc G and Lyc T significantly increased only cell proliferation. Lyc S treatment was ineffective. The highest amount of lycopene in Lyc W was able to counteract and revert the cell survival effect of tocochromanols supporting the importance of evaluating the lycopene bio-availability and the real effect of antioxidant tocochromanols' supplementation which may not only have no anticancer benefits but may even increase cancer aggressivity.

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.

Eosinophilic Chronic Obstructive Pulmonary Disease

Recent therapeutic advances in the management of asthma have underscored the importance of eosinophilia and the role of pro-eosinophilic mediators such as IL-5 in asthma. Given that a subset of patients with COPD may display peripheral eosinophilia similar to what is observed in asthma, a number of recent studies have implied that eosinophilic COPD is a distinct entity. This review will seek to contrast the mechanisms of eosinophilia in asthma and COPD, the implications of eosinophilia for disease outcome, and review current data regarding the utility of peripheral blood eosinophilia in the management of COPD patients.

Cigarette smoke upregulates Notch-1 signaling pathway and promotes lung adenocarcinoma progression

Notch-1 pathway plays an important role in lung carcinoma, stem cell regulation, cellular communication, growth and differentiation. Cigarette smoke is involved in the regulation of Notch signaling. However, current data regarding the impact of cigarette smoke on the Notch pathway in lung cancer progression are limited. The present study aimed to explore whether cigarette smoke exposure altered Notch-1 pathway in ex-vivo (surgical samples of lung parenchyma from non-smoker and smoker patients with lung adenocarcinoma) and in vitro (adenocarcinoma A549 cell line) approaches. The expression of Notch-1, Jagged-1 and CD133 in surgical samples was evaluated by immunohistochemistry. A549 were exposed to cigarette smoke extracts (2.5% and 5% CSE for 6, 24 and 48 h) and the expression of Notch-1, Jagged-1 and Hes-1 was evaluated by Real-Time PCR and Western Blot (nuclear fractions). Expression and localization of Notch-1, Hes-1, CD133 and ABCG2 were assessed by immunofluorescence. The expression of survivin and Ki-67 was assessed by flow cytometry following CSE exposure and inhibition of Notch-1 signaling. Smokers lung parenchyma exhibited higher expression of Notch-1. CSE exposure increased Notch-1 and Hes-1 gene and nuclear protein expression in A549. Immunofluorescence confirmed higher expression of nuclear Hes-1 in CSE-stimulated A549 cells. CSE increased both survivin and Ki-67 expression and this effect was reverted by inhibition of the Notch-1 pathway. In conclusion, these data show that cigarette smoke may promote adenocarcinoma progression by activating the Notch-1 pathway thus supporting its role as hallmark of lung cancer progression and as a new target for lung cancer treatment.

GSK-3β Inhibitors Attenuate the PM2.5-Induced Inflammatory Response in Bronchial Epithelial Cells

Background and Purpose

PM2.5-associated airway inflammation has recently been recognized as pivotal to the development of COPD. Aberrant glycogen synthase kinase (GSK)-3β signaling is linked to the inflammatory response. Therefore, we investigated the effects of GSK-3β inhibitors on the PM2.5-induced inflammatory response in bronchial epithelial cells.

Methods

The production of phosphorylated GSK-3β (p-GSK-3β) was analyzed by immunohistochemistry with PM2.5-induced mice. HBECs were treated with various inhibitors targeting GSK-3β or JNK before PM2.5 stimulation. The production of GSK-3β signaling was analyzed by Western blotting. Inflammatory cytokine production was detected by qRT–PCR and ELISA.

Results

PM2.5 exposure caused lung inflammation, upregulated serum concentrations of HMGB1 and IL-6, decreased IL-10 expression, and significantly attenuated p-GSK-3β production in mice. HBECs exposed to PM2.5 showed significantly reduced p-GSK-3β production, an increased ratio of p-JNK/JNK, increased NF-κB activation and IκB degradation, and upregulated the inflammatory cytokines HMGB1 and IL-6. Intervention with GSK-3β inhibitors TDZD-8 and SB216763 significantly suppressed PM2.5-induced outcomes. Moreover, the JNK inhibitor SP600125 also reduced the level of NF-κB phosphorylation induced by PM2.5. The differences in the levels of inflammation-related cytokines in the TDZD-8 groups were greater than those in the SB216763 groups.

Conclusion

Inhibition of GSK-3β weakens the PM2.5-induced inflammatory response by regulating the JNK/NF-κB signaling pathway in bronchial epithelial cells.

Validation of in vitro models for smoke exposure of primary human bronchial epithelial cells

RATIONALE

The bronchial epithelium is constantly challenged by inhalative insults including cigarette smoke (CS), a key risk factor for lung disease. In vitro exposure of bronchial epithelial cells using CS extract (CSE) is a widespread alternative to whole CS (wCS) exposure. However, CSE exposure protocols vary considerably between studies, precluding direct comparison of applied doses. Moreover, they are rarely validated in terms of physiological response in vivo and the relevance of the findings is often unclear.

METHODS

We tested six different exposure settings in primary human bronchial epithelial cells (phBECs), including five CSE protocols in comparison with wCS exposure. We quantified cell-delivered dose and directly compared all exposures using expression analysis of 10 well-established smoke-induced genes in bronchial epithelial cells. CSE exposure of phBECs was varied in terms of differentiation state, exposure route, duration of exposure, and dose. Gene expression was assessed by quantitative Real-Time PCR (qPCR) and Western Blot analysis. Cell type-specific expression of smoke-induced genes was analyzed by immunofluorescent analysis.

RESULTS

Three surprisingly dissimilar exposure types, namely chronic CSE treatment of differentiating phBECs, acute CSE treatment of submerged basal phBECs, and wCS exposure of differentiated phBECs performed best, resulting in significant upregulation of seven (chronic CSE) and six (acute wCS, acute submerged CSE exposure) out of 10 genes. Acute apical or basolateral exposure of differentiated phBECs with CSE was much less effective despite similar doses used.

CONCLUSIONS

Our findings provide guidance for the design of human in vitro CS exposure models in experimental and translational lung research.

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.

Cigarette smoke extract reduces FOXO3a promoting tumor progression and cell migration in lung cancer

Lung cancer is the leading cause of cancer death worldwide, and the carcinogens in tobacco smoke play a role in its progression and metastasis. The related molecular events are largely unknown. FOXO3a is a transcription factor considered a tumor suppressor. Its inhibition leads to cell transformation, tumor progression and metastasis. The aim of this study was to investigate, in different types of lung cancer cell lines (A549, COLO 699 N, SK-MES-1), the effects of cigarette smoke on mitochondrial status and cell metabolism and on key pathways involved in tumor progression and cell migration, looking at the role of FOXO3a in these mechanisms. The different lung cancer cells were exposed to cigarette smoke extract (CSE) and TGF-β1. Reactive oxygen species (ROS), mitochondrial superoxide, intracellular ATP, extracellular lactate, FOXO3a, p21, survivin, epithelial-to-mesenchymal transition (EMT) markers (E-cadherin, SNAIL1), MMP-9 and cellular migration were assessed by flow-cytometry, fluorimetry, western blot analysis, Real-Time PCR and scratch test. Our results showed that exposure to CSE: (i) increased ROS, mitochondrial superoxide, lactate release while reducing intracellular ATP; (ii) decreased FOXO3a and increased survivin and p21 in the cytoplasm; (iii) decreased E-cadherin, increased SNAIL1 and MMP-9 and promoted cell migration like TGF-β1 did. These effects could be partly explained by downregulation of FOXO3a, as demonstrated by silencing experiments. These data suggest that cigarette smoke induces oxidative stress and mitochondrial damage leading to metabolic reprogramming associated with increased glycolytic flux. This is accompanied with a downregulation of FOXO3a contributing to EMT processes and cell migration therefore promoting tumor progression.

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.

Sulforaphane ameliorates steroid insensitivity through an Nrf2-dependent pathway in cigarette smoke-exposed asthmatic mice

Oxidative stress induced by cigarette smoke and other environmental pollutants contributes to refractory asthma. To better understand the role of smoking in asthma, we investigated the effects of cigarette smoke on allergic airway responses in mice and examined expression of nuclear factor-E2-related factor-2 (Nrf2) and its downstream factors, because Nrf2 is known to play a pivotal role in antioxidant responses. OVA-sensitized and challenged BALB/c mice were exposed to cigarette smoke and then treated with dexamethasone, sulforaphane (an activator of Nrf2), or their combination. Upon exposure to cigarette smoke, Nrf2 and associated transcripts were upregulated in response to oxidative stress, and asthmatic responses were steroid resistant. In OVA-sensitized and challenged mice exposed to cigarette smoke and treated with sulforaphane, Nrf2-mediated antioxidant responses were upregulated to a greater extent, and steroid sensitivity of asthmatic responses was restored. Moreover, the expression and activity of histone deacetylase 2 (HDAC2), a key regulator of steroid responsiveness, was reduced in mice exposed to cigarette smoke, but restored by sulforaphane treatment. No effects of sulforaphane were observed in Nrf2-deficient mice. These findings indicate that cigarette smoke induces steroid unresponsiveness in asthmatic airways, and that sulforaphane restores steroid sensitivity via upregulation of Nrf2 and enhancement of HDAC2 expression and activity. Thus, Nrf2 may serve as a potential molecular target for cigarette smoke-related refractory asthma resistant to steroid therapy.

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.