SARS-CoV-2 infection as a model to study the effect of cinnamaldehyde as adjuvant therapy for viral pneumonia.

BACKGROUND: The recent pandemic outbursts, due to SARS-CoV-2, have highlighted once more the central role of the inflammatory process in the propagation of viral infection. The main consequence of COVID-19 is the induction of a diffuse pro-inflammatory state, also defined as a cytokine storm, which affects different organs, but mostly the lungs. We aimed to prove the efficacy of cinnamaldehyde, the active compound of cinnamon, as an anti-inflammatory compound, able to reduce SARS-CoV-2 induced cytokine storm. RESULTS: We enrolled 53 COVID-19 patients hospitalized for respiratory failure. The cohort was composed by 39 males and 13 females, aged 65.0 ± 9.8 years. We reported that COVID-19 patients have significantly higher IL-1ß and IL-6 plasma levels compared to non-COVID-19 pneumonia patients. In addition, human mononuclear cells (PBMCs) isolated from SARS-CoV-2 infected patients are significantly more prone to release pro-inflammatory cytokines upon stimuli. We demonstrated, using in vitro cell models, that macrophages are responsible for mediating the pro-inflammatory cytokine storm while lung cells support SARS-CoV-2 replication upon viral infection. In this context, cinnamaldehyde administration significantly reduces SARS-CoV-2-related inflammation by inhibiting NLRP3 mediated IL-1ß release in both PBMCs and THP-1 macrophages, as well as viral replication in CaLu-3 epithelial cells. Lastly, aerosol-administered cinnamaldehyde was able to significantly reduce IL-1ß release in an in vivo lung-inflammatory model. CONCLUSION: The obtained results suggest the possible use of cinnamaldehyde as a co-adjuvant preventive treatment for COVID-19 disease together with vaccination, but also as a promising dietary supplement to reduce, more broadly, viral induced inflammation.

Differential responses of pulmonary vascular cells from PAH patients and controls to TNFα and the effect of the BET inhibitor JQ1.

BACKGROUND: Pulmonary arterial hypertension (PAH) encompasses a group of diseases characterized by raised pulmonary vascular resistance, resulting from vascular remodelling and inflammation. Bromodomain and extra-terminal (BET) proteins are required for the expression of a subset of NF-κB-induced inflammatory genes which can be inhibited by the BET mimic JQ1+. We hypothesised that JQ+ would supress TNFα-driven inflammatory responses in human pulmonary vascular cells from PAH patients. METHODS: Immunohistochemical staining of human peripheral lung tissue (N = 14 PAH and N = 12 non-PAH) was performed for the BET proteins BRD2 and 4. Human pulmonary microvascular endothelial cells (HPMEC) and pulmonary artery smooth muscle cells (HPASMC) from PAH patients (N = 4) and non-PAH controls (N = 4) were stimulated with TNFα in presence or absence of JQ1+ or its inactive isomer JQ1-. IL-6 and -8 mRNA was measured by RT-qPCR and protein levels by ELISA. Chromatin immunoprecipitation analysis was performed using EZ-ChIP™ and NF-κB p65 activation determined using a TransAm kit. MTT assay was used to measure cell viability. RESULTS: Nuclear staining of BRD2 and BRD4 was significantly (p < 0.0001) increased in the lung vascular endothelial and smooth muscle cells from PAH patients compared to controls with normal lung function. TNFα-driven IL-6 release from both HPMECs and HPASMCs was greater in PAH cells than control cells. Levels of CXCL8/IL-8 protein release was higher in PAH HPASMCs than in control cells with similar release observed in HPMECs. TNFα-induced recruitment of activated NF-κB p65 to the IL-6 and CXCL8/IL-8 promoters were similar in both cell types and between subject groups. JQ1+ suppressed TNFα-induced IL-6 and CXCL8/IL-8 release and mRNA expression to a comparable extent in control and PAH HPMECs and HPASMCs. JQ1 had a greater efficacy on IL-6 release in HPMEC and on CXCL8/IL-8 release in HPASMC. CONCLUSION: BET inhibition decreases TNFα driven inflammation in primary pulmonary vascular cells. The anti-inflammatory actions of JQ1 suggests distinct cell-specific regulatory control of these genes. BET proteins could be a target for future therapies for PAH.

Rhinovirus-induced CCL17 and CCL22 in Asthma Exacerbations and Differential Regulation by STAT6.

The interplay of type-2 inflammation and antiviral immunity underpins asthma exacerbation pathogenesis. Virus infection induces type-2 inflammation-promoting chemokines CCL17 and CCL22 in asthma; however, mechanisms regulating induction are poorly understood. By using a human rhinovirus (RV) challenge model in human airway epithelial cells in vitro and mice in vivo, we assessed mechanisms regulating CCL17 and CCL22 expression. Subjects with mild to moderate asthma and healthy volunteers were experimentally infected with RV and airway CCL17 and CCL22 protein quantified. In vitro airway epithelial cell- and mouse-RV infection models were then used to define STAT6- and NF-κB-mediated regulation of CCL17 and CCL22 expression. Following RV infection, CCL17 and CCL22 expression was higher in asthma, which differentially correlated with clinical and immunological parameters. Air-liquid interface-differentiated primary epithelial cells from donors with asthma also expressed higher levels of RV-induced CCL22. RV infection boosted type-2 cytokine-induced STAT6 activation. In epithelial cells, type-2 cytokines and STAT6 activation had differential effects on chemokine expression, increasing CCL17 and suppressing CCL22, whereas NF-κB promoted expression of both chemokines. In mice, RV infection activated pulmonary STAT6, which was required for CCL17 but not CCL22 expression. STAT6-knockout mice infected with RV expressed increased levels of NF-κB-regulated chemokines, which was associated with rapid viral clearance. Therefore, RV-induced upregulation of CCL17 and CCL22 was mediated by NF-κB activation, whereas expression was differentially regulated by STAT6. Together, these findings suggest that therapeutic targeting of type-2 STAT6 activation alone will not block all inflammatory pathways during RV infection in asthma.

Glucocorticoids impair type I IFN signalling and enhance rhinovirus replication.

Inhaled corticosteroids (ICS) are recommended treatments for all degrees of asthma severity and in combination with bronchodilators are indicated for COPD patients with a history of frequent exacerbations. However, the long-term side effects of glucocorticoids (GCs) may include increased risk of respiratory infections, including viral triggered exacerbations. Rhinovirus (RV) infection is the main trigger of asthma and COPD exacerbations. Thus, we sought to explore the influence of GCs on viral replication. We demonstrate the ICS fluticasone propionate (FP) and two selective non-steroidal (GRT7) and steroidal (GRT10) glucocorticoid receptor (GR) agonists significantly suppress pro-inflammatory (IL-6 and IL-8) and antiviral (IFN-λ1) cytokine production and the expression of the interferon-stimulated genes (ISGs) OAS and viperin in RV-infected bronchial epithelial cells, with a consequent increase of viral replication. We also show that FP, GRT7 and GRT10 inhibit STAT1 Y701 and/or STAT2 Y690 phosphorylation and ISG mRNA induction following cell stimulation with recombinant IFN-ß. In addition, we investigated the effects of the ICS budesonide (BD) and the long-acting ß2 agonist (LABA) formoterol, alone or as an ICS/LABA combination, on RV-induced ISG expression and viral replication. Combination of BD/formoterol increases the suppression of OAS and viperin mRNA observed with both BD and formoterol alone, but an increase in viral RNA was only observed with BD treatment and not with formoterol. Overall, we provide evidence of an impairment of the innate antiviral immune response by GC therapy and the potential for GCs to enhance viral replication. These findings could have important clinical implications.

Airway inflammatory profile is correlated with symptoms in stable COPD: A longitudinal proof-of-concept cohort study.

BACKGROUND AND OBJECTIVE: Symptoms negatively impact the quality of life and long-term prognosis of patients with chronic obstructive pulmonary disease (COPD). Little is known about the relationship linking airway inflammation and symptoms in stable COPD. In this study, we evaluated whether respiratory symptoms in COPD are related to sputum inflammatory cellular profile and whether symptom changes are associated with changes in airway inflammation. METHODS: A total of 40 patients with stable COPD with moderate-to-severe airflow obstruction were enrolled. Patients were visited weekly over 4 weeks. At each visit, patients underwent clinical assessments, lung function tests and sputum induction. Patients recorded daily dyspnoea, sputum and cough scores. RESULTS: The changes between two consecutive visits in the percent of sputum neutrophils and eosinophils were related to the changes in the cough (P < 0.001; r = 0.63) and dyspnoea scores (P < 0.001; r = 0.58) of the prior week. Furthermore, using regression analyses, we were able to demonstrate that changes in the cough score were specifically associated to the change in neutrophils, while changes in the dyspnoea score and use of rescue medications were associated with changes in eosinophils numbers. CONCLUSION: Our study showed an association between symptoms and the sputum inflammatory profile. In particular, changes in symptoms (cough and dyspnoea) were correlated with changes in the specific sputum inflammatory cell components of airway inflammation (neutrophils and eosinophils, respectively), providing novel information on the mechanisms of disease manifestation.

IL-22 and its receptors are increased in human and experimental COPD and contribute to pathogenesis.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of morbidity and death globally. The lack of effective treatments results from an incomplete understanding of the underlying mechanisms driving COPD pathogenesis.Interleukin (IL)-22 has been implicated in airway inflammation and is increased in COPD patients. However, its roles in the pathogenesis of COPD is poorly understood. Here, we investigated the role of IL-22 in human COPD and in cigarette smoke (CS)-induced experimental COPD.IL-22 and IL-22 receptor mRNA expression and protein levels were increased in COPD patients compared to healthy smoking or non-smoking controls. IL-22 and IL-22 receptor levels were increased in the lungs of mice with experimental COPD compared to controls and the cellular source of IL-22 included CD4+ T-helper cells, γδ T-cells, natural killer T-cells and group 3 innate lymphoid cells. CS-induced pulmonary neutrophils were reduced in IL-22-deficient (Il22 -/-) mice. CS-induced airway remodelling and emphysema-like alveolar enlargement did not occur in Il22 -/- mice. Il22 -/- mice had improved lung function in terms of airway resistance, total lung capacity, inspiratory capacity, forced vital capacity and compliance.These data highlight important roles for IL-22 and its receptors in human COPD and CS-induced experimental COPD.

Differential expression of RNA-binding proteins in bronchial epithelium of stable COPD patients.

PURPOSE: Inflammatory gene expression is modulated by posttranscriptional regulation via RNA-binding proteins (RBPs), which regulate mRNA turnover and translation by binding to conserved mRNA sequences. Their role in COPD is only partially defined. This study evaluated RBPs tristetraprolin (TTP), human antigen R (HuR), and AU-rich element-binding factor 1 (AUF-1) expression using lung tissue from COPD patients and control subjects and probed their function in epithelial responses in vitro. PATIENTS AND METHODS: RBPs were detected by immunohistochemistry in bronchial and peripheral lung samples from mild-to-moderate stable COPD patients and age/smoking history-matched controls; RBPs and RBP-regulated genes were evaluated by Western blot, ELISA, protein array, and real-time PCR in human airway epithelial BEAS-2B cell line stimulated with hydrogen peroxide, cytokine combination (cytomix), cigarette smoke extract (CSE), and following siRNA-mediated silencing. Results were verified in a microarray database from bronchial brushings of COPD patients and controls. RBP transcripts were measured in peripheral blood mononuclear cell samples from additional stable COPD patients and controls. RESULTS: Specific, primarily nuclear immunostaining for the RBPs was detected in structural and inflammatory cells in bronchial and lung tissues. Immunostaining for AUF-1, but not TTP or HuR, was significantly decreased in bronchial epithelium of COPD samples vs controls. In BEAS-2B cells, cytomix and CSE stimulation reproduced the RBP pattern while increasing expression of AUF-1-regulated genes, interleukin-6, CCL2, CXCL1, and CXCL8. Silencing expression of AUF-1 reproduced, but not enhanced, target upregulation induced by cytomix compared to controls. Analysis of bronchial brushing-derived transcriptomic confirmed the selective decrease of AUF-1 in COPD vs controls and revealed significant changes in AUF-1-regulated genes by genome ontology. CONCLUSION: Downregulated AUF-1 may be pathogenic in stable COPD by altering posttranscriptional control of epithelial gene expression.

The anti-proliferative and anti-inflammatory response of COPD airway smooth muscle cells to hydrogen sulfide.

BACKBROUND: COPD is a common, highly debilitating disease of the airways, primarily caused by smoking. Chronic inflammation and structural remodelling are key pathological features of this disease caused, in part, by the aberrant function of airway smooth muscle (ASM). We have previously demonstrated that hydrogen sulfide (H2S) can inhibit ASM cell proliferation and CXCL8 release, from cells isolated from non-smokers. METHODS: We examined the effect of H2S upon ASM cells from COPD patients. ASM cells were isolated from non-smokers, smokers and patients with COPD (n = 9). Proliferation and cytokine release (IL-6 and CXCL8) of ASM was induced by FCS, and measured by bromodeoxyuridine incorporation and ELISA, respectively. RESULTS: Exposure of ASM to H2S donors inhibited FCS-induced proliferation and cytokine release, but was less effective upon COPD ASM cells compared to the non-smokers and smokers. The mRNA and protein expression of the enzymes responsible for endogenous H2S production (cystathionine-ß-synthase [CBS] and 3-mercaptopyruvate sulphur transferase [MPST]) were inhibited by H2S donors. Finally, we report that exogenous H2S inhibited FCS-stimulated phosphorylation of ERK-1/2 and p38 mitogen activated protein kinases (MAPKs), in the non-smoker and smoker ASM cells, with little effect in COPD cells. CONCLUSIONS: H2S production provides a novel mechanism for the repression of ASM proliferation and cytokine release. The ability of COPD ASM cells to respond to H2S is attenuated in COPD ASM cells despite the presence of the enzymes responsible for H2S production.

TGF-ß Signaling Pathways in Different Compartments of the Lower Airways of Patients With Stable COPD.

BACKGROUND: The expression and localization of transforming growth factor-ß (TGF-ß) pathway proteins in different compartments of the lower airways of patients with stable COPD is unclear. We aimed to determine TGF-ß pathway protein expression in patients with stable COPD. METHODS: The expression and localization of TGF-ß pathway components was measured in the bronchial mucosa and peripheral lungs of patients with stable COPD (n = 44), control smokers with normal lung function (n = 24), and control nonsmoking subjects (n = 11) using immunohistochemical analysis. RESULTS: TGF-ß1, TGF-ß3, and connective tissue growth factor expression were significantly decreased in the bronchiolar epithelium, with TGF-ß1 also decreased in alveolar macrophages, in patients with stable COPD compared with control smokers with normal lung function. TGF-ß3 expression was increased in the bronchial lamina propria of both control smokers with normal lung function and smokers with mild/moderate stable COPD compared with control nonsmokers and correlated significantly with pack-years of smoking. However, TGF-ß3+ cells decreased in patients with severe/very severe COPD compared with control smokers. Latent TGF-ß binding protein 1 expression was increased in the bronchial lamina propria in subjects with stable COPD of all severities compared with control smokers with normal lung function. Bone morphogenetic protein and activin membrane-bound inhibitor expression (BAMBI) in the bronchial mucosa was significantly increased in patients with stable COPD of all severities compared with control subjects. No other significant differences were observed between groups for all the other molecules studied in the bronchial mucosa and peripheral lung. CONCLUSIONS: Expression of TGF-ßs and their regulatory proteins is distinct within different lower airway compartments in stable COPD. Selective reduction in TGF-ß1 and enhanced BAMBI expression may be associated with the increase in autoimmunity in COPD.

Lower airways inflammation in patients with ARDS measured using endotracheal aspirates: a pilot study.

INTRODUCTION: Our knowledge of acute respiratory distress syndrome (ARDS) pathogenesis is incomplete. The goal of this pilot study is to investigate the feasibility of measuring lower airways inflammation in patients with ARDS using repeated endotracheal aspirates (ETAs). METHODS: ETAs were obtained within 24 hours by intensive care unit admission from 25 mechanically ventilated patients with ARDS and 10 of them underwent a second ETA within 96 hours after the first sampling. In each sample, cell viability was assessed using trypan blue exclusion method and the total and differential cell counts were measured using Neubauer-improved cell counting chamber and cytospins stained with Diff-Quik. RESULTS: The median cell viability was 89 (IQR 80-93)%, with a median total cell count of 305 (IQR 130-1270)×103/mL and a median macrophage, neutrophil, lymphocyte and eosinophil count, respectively, of 19.8 (IQR 5.4-71.6)×103/mL; 279 (IQR 109-1213)×103/mL; 0 (IQR 0-0.188)×103/mL; 0 (IQR 0-1.050)×103/mL. Eosinophil count in the ETA correlated with the number of blood eosinophils (r=0.4840, p=0.0142). Cell viability and total and differential cell counts were neither significantly different in the second ETA compared with the first ETA nor were unaffected by the presence or absence of bacteria in the blood and/or ETA, or by the ARDS aetiology, apart from the macrophage count which was significantly increased in patients with ARDS associated with acute pancreatitis compared with those associated with pneumonia (p=0.0143). CONCLUSIONS: ETA can be used to investigate the cellularity of the lower airways in patients with ARDS and it is an easy-to-perform and non-invasive procedure. Eosinophil counts in ETA and blood are significantly correlated. The number of macrophages in ETA may be affected by the aetiology of the ARDS.

Long-term effects of inhaled corticosteroids on sputum bacterial and viral loads in COPD.

Inhaled corticosteroid-containing medications reduce the frequency of COPD exacerbations (mainly infectious in origin) while paradoxically increasing the risk of other respiratory infections. The aim was to determine the effects of inhaled corticosteroids on airway microbial load in COPD patients and evaluate the influence of the underlying inflammatory profile on airway colonisation and microbiome.This is a proof-of-concept prospective, randomised, open-label, blinded endpoint study. Sixty patients with stable moderate COPD were randomised to receive one inhalation twice daily of either a combination of salmeterol 50 µg plus fluticasone propionate 500 µg or salmeterol 50 µg for 12 months. The primary outcome was the change of sputum bacterial loads over the course of treatment.Compared with salmeterol, 1-year treatment with salmeterol plus fluticasone was associated with a significant increase in sputum bacterial load (p=0.005), modification of sputum microbial composition and increased airway load of potentially pathogenic bacteria. The increased bacterial load was observed only in inhaled corticosteroid-treated patients with lower baseline sputum or blood eosinophil (≤2%) levels but not in patients with higher baseline eosinophils.Long-term inhaled corticosteroid treatment affects bacterial load in stable COPD. Lower eosinophil counts are associated with increased airway bacterial load.

Fluticasone furoate and vilanterol for the treatment of chronic obstructive pulmonary disease.

INTRODUCTION: Current national and international guidelines for the management of patients with stable chronic obstructive pulmonary disease (COPD) recommend the use of inhaled long-acting bronchodilators, inhaled glucocorticoids and their combinations for maintenance treatment of moderate to severe stable COPD. Areas covered: The role of fluticasone furoate (FF) and vilanterol (VI) once daily combination therapy for the regular treatment of patients with stable COPD is discussed in this review. Expert commentary: The regular treatment of moderate to severe stable COPD with once daily FF/VI combination therapy is effective, as seen in in several large placebo-controlled clinical trials involving many thousands of patients. FF/VI improved lung function, decreased respiratory symptoms and decreased the number of COPD exacerbations, including COPD-related hospitalizations. FF/VI combination therapy has also been approved for this indication in most countries. The use of this combination therapy may significantly decrease the economic costs for some National Health Services.

Nasal inflammation and its response to local glucocorticoid regular treatment in patients with persistent non-allergic rhinitis: a pilot study.

BACKGROUND: The pathogenesis of non-allergic rhinitis (NAR) is still largely unknown. Furthermore, it is unclear whether there is a correlation between the effect of nasal glucocorticoids on nasal inflammation and on nasal symptoms and quality of life. METHODS: In this pilot study we recruited 12 healthy subjects and 24 patients with recently diagnosed persistent NAR [12 untreated and 12 under regular treatment with nasal fluticasone furoate (two sprays of 27.5 µg each in each nostril once daily, total daily dose = 110 µg) for at least 20 days]. Each subject filled a mini rhinoconjunctivitis quality of life questionnaire (mini RQLQ). Nasal scrapings were obtained from each subject and used to prepare slides for Diff-Quik and immunocytochemical staining for inflammatory and epithelial cells count, MUC5AC expression and the general pro-inflammatory transcription factor nuclear factor kB (NF-kB) activation. RESULTS: The nasal score of the mini RQLQ, the number of nasal inflammatory cells (neutrophils, eosinophils) and the number of goblet cells are significantly higher in untreated patients with persistent NAR compared with control subjects and treated NAR patients. The percentage of MUC5AC+ nasal epithelial cells is significantly increased in untreated patients with persistent NAR compared with the control subjects (41.8 ± 6.4 vs 22.3 ± 4.8, respectively; p = 0.0403) without significant differences between control subjects and patients with persistent NAR on regular fluticasone furoate treatment (33.9 ± 5.0 %; p = 0.0604) nor between the 2 groups of persistent NAR subjects (p = 0.3260). The number of cytosolic and/or nuclear p65+ nasal epithelial and inflammatory cells was not significantly different between the three groups. CONCLUSIONS: Patients with persistent untreated NAR, compared with normal control subjects and patients with persistent NAR under regular treatment with nasal fluticasone furoate by at least 20 days, have more nasal symptoms, worst quality of life and an increased number of nasal inflammatory cells (neutrophils, eosinophils), goblet cells and MUC5AC+ nasal epithelial cells. This nasal inflammation seems unrelated to NF-kB activation.

COPD immunopathology.

The immunopathology of chronic obstructive pulmonary disease (COPD) is based on the innate and adaptive inflammatory immune responses to the chronic inhalation of cigarette smoking. In the last quarter of the century, the analysis of specimens obtained from the lower airways of COPD patients compared with those from a control group of age-matched smokers with normal lung function has provided novel insights on the potential pathogenetic role of the different cells of the innate and acquired immune responses and their pro/anti-inflammatory mediators and intracellular signalling pathways, contributing to a better knowledge of the immunopathology of COPD both during its stable phase and during its exacerbations. This also has provided a scientific rationale for new drugs discovery and targeting to the lower airways. This review summarises and discusses the immunopathology of COPD patients, of different severity, compared with control smokers with normal lung function.

Glycogen synthase kinase-3ß modulation of glucocorticoid responsiveness in COPD.

In chronic obstructive pulmonary disease (COPD), oxidative stress regulates the inflammatory response of bronchial epithelium and monocytes/macrophages through kinase modulation and has been linked to glucocorticoid unresponsiveness. Glycogen synthase-3ß (GSK3ß) inactivation plays a key role in mediating signaling processes upon reactive oxygen species (ROS) exposure. We hypothesized that GSK3ß is involved in oxidative stress-induced glucocorticoid insensitivity in COPD. We studied levels of phospho-GSK3ß-Ser9, a marker of GSK3ß inactivation, in lung sections and cultured monocytes and bronchial epithelial cells of COPD patients, control smokers, and nonsmokers. We observed increased levels of phospho-GSK3ß-Ser9 in monocytes, alveolar macrophages, and bronchial epithelial cells from COPD patients and control smokers compared with nonsmokers. Pharmacological inactivation of GSK3ß did not affect CXCL8 or granulocyte-macrophage colony-stimulating factor (GM-CSF) expression but resulted in glucocorticoid insensitivity in vitro in both inflammatory and structural cells. Further mechanistic studies in monocyte and bronchial epithelial cell lines showed that GSK3ß inactivation is a common effector of oxidative stress-induced activation of the MEK/ERK-1/2 and phosphatidylinositol 3-kinase/Akt signaling pathways leading to glucocorticoid unresponsiveness. In primary monocytes, the mechanism involved modulation of histone deacetylase 2 (HDAC2) activity in response to GSK3ß inactivation. In conclusion, we demonstrate for the first time that ROS-induced glucocorticoid unresponsiveness in COPD is mediated through GSK3ß, acting as a ROS-sensitive hub.

Phospho-p38 MAPK expression in COPD patients and asthmatics and in challenged bronchial epithelium.

BACKGROUND: The role of mitogen-activated protein kinases (MAPK) in regulating the inflammatory response in the airways of patients with chronic obstructive pulmonary disease (COPD) and asthmatic patients is unclear. OBJECTIVES: To investigate the expression of activated MAPK in lungs of COPD patients and in bronchial biopsies of asthmatic patients and to study MAPK expression in bronchial epithelial cells in response to oxidative and inflammatory stimuli. METHODS: Immunohistochemical expression of phospho (p)-p38 MAPK, p-JNK1 and p-ERK1/2 was measured in bronchial mucosa in patients with mild/moderate (n = 17), severe/very severe (n = 16) stable COPD, control smokers (n = 16), control non-smokers (n = 9), in mild asthma (n = 9) and in peripheral airways from COPD patients (n = 15) and control smokers (n = 15). Interleukin (IL)-8 and MAPK mRNA was measured in stimulated 16HBE cells. RESULTS: No significant differences in p-p38 MAPK, p-JNK or p-ERK1/2 expression were seen in bronchial biopsies and peripheral airways between COPD and control subjects. Asthmatics showed increased submucosal p-p38 MAPK expression compared to COPD patients (p < 0.003) and control non-smokers (p < 0.05). Hydrogen peroxide (H2O2), cytomix (tumour necrosis factor-α + IL-1ß + interferon-γ) and lipopolysaccharide (LPS) upregulated IL-8 mRNA at 1 or 2 h. p38 MAPKα mRNA was significantly increased after H2O2 and LPS treatment. JNK1 and ERK1 mRNA were unchanged after H2O2, cytomix or LPS treatments. CONCLUSION: p-p38 MAPK expression is similar in stable COPD and control subjects but increased in the bronchi of mild asthmatics compared to stable COPD patients. p38 MAPK mRNA is increased after bronchial epithelial challenges in vitro. These data together suggest a potential role for this MAPK in Th2 inflammation and possibly during COPD exacerbations.

Nuclear IL-33 regulates soluble ST2 receptor and IL-6 expression in primary human arterial endothelial cells and is decreased in idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is an incurable condition leading to right ventricular failure and death and inflammation is postulated to be associated with vascular remodelling. Interleukin (IL)-33, a member of the "alarmin" family can either act on the membrane ST2 receptor or as a nuclear repressor, to regulate inflammation. We show, using immunohistochemistry, that IL-33 expression is nuclear in the vessels of healthy subjects whereas nuclear IL-33 is markedly diminished in the vessels of IPAH patients. This correlates with reduced IL-33 mRNA expression in their lung. In contrast, serum levels of IL-33 are unchanged in IPAH. However, the expression of the soluble form of ST2, sST2, is enhanced in the serum of IPAH patients. Knock-down of IL-33 in human endothelial cells (ECs) using siRNA is associated with selective modulation of inflammatory genes involved in vascular remodelling including IL-6. Additionally, IL-33 knock-down significantly increased sST2 release from ECs. Chromatin immunoprecipitation demonstrated that IL-33 bound multiple putative homeodomain protein binding motifs in the proximal and distal promoters of ST2 genes. IL-33 formed a complex with the histone methyltransferase SUV39H1, a transcriptional repressor. In conclusion, IL-33 regulates the expression of IL-6 and sST2, an endogenous IL-33 inhibitor, in primary human ECs and may play an important role in the pathogenesis of PAH through recruitment of transcriptional repressor proteins.

Innate immunity but not NLRP3 inflammasome activation correlates with severity of stable COPD.

BACKGROUND: In models of COPD, environmental stressors induce innate immune responses, inflammasome activation and inflammation. However, the interaction between these responses and their role in driving pulmonary inflammation in stable COPD is unknown. OBJECTIVES: To investigate the activation of innate immunity and inflammasome pathways in the bronchial mucosa and bronchoalveolar lavage (BAL) of patients with stable COPD of different severity and control healthy smokers and non-smokers. METHODS: Innate immune mediators (interleukin (IL)-6, IL-7, IL-10, IL-27, IL-37, thymic stromal lymphopoietin (TSLP), interferon γ and their receptors, STAT1 and pSTAT1) and inflammasome components (NLRP3, NALP7, caspase 1, IL-1ß and its receptors, IL-18, IL-33, ST2) were measured in the bronchial mucosa using immunohistochemistry. IL-6, soluble IL-6R, sgp130, IL-7, IL-27, HMGB1, IL-33, IL-37 and soluble ST2 were measured in BAL using ELISA. RESULTS: In bronchial biopsies IL-27+ and pSTAT1+ cells are increased in patients with severe COPD compared with control healthy smokers. IL-7+ cells are increased in patients with COPD and control smokers compared with control non-smokers. In severe stable COPD IL-7R+, IL-27R+ and TSLPR+ cells are increased in comparison with both control groups. The NALP3 inflammasome is not activated in patients with stable COPD compared with control subjects. The inflammasome inhibitory molecules NALP7 and IL-37 are increased in patients with COPD compared with control smokers. IL-6 levels are increased in BAL from patients with stable COPD compared with control smokers with normal lung function whereas IL-1ß and IL-18 were similar across all groups. CONCLUSIONS: Increased expression of IL-27, IL-37 and NALP7 in the bronchial mucosa may be involved in progression of stable COPD.

Nuclear factor κ-B is activated in the pulmonary vessels of patients with end-stage idiopathic pulmonary arterial hypertension.

OBJECTIVES: To assess activation of the inflammatory transcription factor NF-kappa B (NF-κB) in human idiopathic pulmonary arterial hypertension (PAH). BACKGROUND: Idiopathic PAH is a severe progressive disease characterized by pulmonary vascular remodeling and excessive proliferation of vascular cells. Increasing evidence indicates that inflammation is important in disease pathophysiology. METHODS: NF-κB-p65 and CD68, CD20 and CD45 were measured by immunohistochemistry and confocal microscopy on lung specimens from patients with idiopathic PAH (n = 12) and controls undergoing lung surgery (n = 14). Clinical data were recorded for all patients including invasive pulmonary hemodynamics for the PAH patients. Immunohistochemical images were analyzed by blinded observers to include standard pulmonary vascular morphometry; absolute macrophage counts/mm(2) and p65-positivity (p65+) using composite images and image-analysis software; and cytoplasmic:nuclear p65+ of individual pulmonary arterial endothelial and smooth muscle cells (PASMC) in 10-20 pulmonary arteries or arterioles per subject. The expression of ET-1 and CCL5 (RANTES) in whole lung was determined by RT-qPCR. RESULTS: Macrophage numbers were increased in idiopathic PAH versus controls (49.0±4.5 vs. 7.95±1.9 macrophages/100 mm(2), p<0.0001): these macrophages demonstrated more nuclear p65+ than in macrophages from controls (16.9±2.49 vs. 3.5±1.25%, p<0.001). An increase in p65+ was also seen in perivascular lymphocytes in patients with PAH. Furthermore, NF-κB activation was increased in pulmonary arterial endothelial cells (62.3±2.9 vs. 14.4±3.8, p<0.0001) and PASMC (22.6±2.3 vs. 11.2±2.0, p<0.001) in patients with PAH versus controls, with similar findings in arterioles. Gene expression of both ET-1 mRNA ((0.213±0.069 vs. 1.06±0.23, p<0.01) and CCL5 (RANTES) (0.16±0.045 vs. 0.26±0.039, p<0.05) was increased in whole lung homogenates from patients with PAH. CONCLUSIONS: NF-κB is activated in pulmonary macrophages, lymphocytes, endothelial and PASMC in patients with end-stage idiopathic PAH. Future research should determine whether NF-κB activation is a driver or bystander of pulmonary vascular inflammation and if the former, its potential role as a therapeutic target.