Upregulation of adhesion molecules in the bronchial mucosa of subjects with chronic obstructive bronchitis

Exploration of the Shared Gene Signatures and Molecular Mechanisms between Chronic Bronchitis and Antineutrophil Cytoplasmic Antibody-associated Glomerulonephritis: Evidence from Transcriptome Data

BACKGROUND

Chronic Bronchitis (CB) is a recurrent and persistent pulmonary inflammation disease. Growing evidence suggests an association between CB and Anti-neutrophil Cytoplasmic Antibody-associated Glomerulonephritis (ANCA-GN). However, the precise mechanisms underlying their association remain unclear.

AIMS

The purpose of this study was to further explore the molecular mechanism of the occurrence of chronic bronchitis (CB) associated with anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA- GN).

OBJECTIVE

Our study aimed to investigate the potential shared pathogenesis of CB-associated ANCA-GN.

METHODS

Datasets of ANCA (GSE108113 and GSE104948) and CB (GSE151052 and GSE162635) were obtained from the Gene Expression Omnibus (GEO) datasets. Firstly, GSE108113 and GSE151052 were analyzed to identify common differentially expressed genes (DEGs) by Limma package. Based on common DEGs, protein-protein interaction (PPI) network and functional enrichment analyses, including GO, KEGG, and GSEA, were performed. Then, hub genes were identified by degree algorithm and validated in GSE104948 and GSE162635. Further PPI network and functional enrichment analyses were performed on hub genes. Additionally, a competitive ceRNA network was constructed through miRanda and spongeScan. Transcription factors (TFs) were predicted and verified using the TRRUST database. Furthermore, the CIBERSORT algorithm was employed to explore immune cell infiltration. The Drug Gene Interaction Database (DGIDB) was utilized to predict small-molecular compounds of CB and ANCA-GN.

RESULTS

A total of 963 DEGs were identified in the integrated CB dataset, and 610 DEGs were identified in the integrated ANCA-GN dataset. Totally, we identified 22 common DEGs, of which 10 hub genes (LYZ, IRF1, PIK3CG, IL2RG, NT5E, ARG2, HBEGF, NFATC2, ALPL, and FKBP5) were primarily involved in inflammation and immune responses. Focusing on hub genes, we constructed a ceRNA network composed of 323 miRNAs and 348 lncRNAs. Additionally, five TFs (SP1, RELA, NFKB1, HIF1A, and SP3) were identified to regulate the hub genes. Furthermore, immune cell infiltration results revealed immunoregulation in CB and ANCA-GN. Finally, some small-molecular compounds (Daclizumab, Aldesleukin, and NT5E) were predicted to predominantly regulate inflammation and immunity, especially IL-2.

CONCLUSION

Our study explores the inflammatory-immune pathways underlying CB-associated ANCA-GN and emphasizes the importance of NETs and lymphocyte differentiation, providing novel insights into the shared pathogenesis and therapeutic targets.

Serum IgA augments adhesiveness of cultured lung microvascular endothelial cells and suppresses angiogenesis

Immunoglobulin A (IgA) is important in local immunity and is also abundant in the blood. This study aimed to evaluate the effects of serum IgA on cultured lung microvascular endothelial cells (HMVEC-Ls), which are involved in the pathogenesis of inflammatory lung diseases. Serum IgA induced adhesion molecules and inflammatory cytokine production from HMVEC-Ls, and enhanced adhesion of peripheral blood mononuclear cells to HMVEC-Ls. In contrast, migration, proliferation, and tube formation of HMVEC-Ls were significantly suppressed by serum IgA. Experiments with siRNAs and western blotting revealed that two known IgA receptors, β1,4-galactosyltransferase 1 (b4GALT1) and asialoglycoprotein receptor 1 (ASGR1), and mitogen-activated protein kinase and nuclear factor-kappa B pathways were partly involved in serum IgA-induced cytokine production by HMVEC-Ls. Collectively, serum IgA enhanced cytokine production and adhesiveness of HMVEC-L, with b4GALT1 and ASGR1 partially being involved, and suppressed angiogenesis. Thus, serum IgA may be targeted to treat inflammatory lung diseases.

Novel Anti-Inflammatory Approaches to COPD

Airway inflammation, driven by different types of inflammatory cells and mediators, plays a fundamental role in COPD and its progression. Neutrophils, eosinophils, macrophages, and CD4+ and CD8+ T lymphocytes are key players in this process, although the extent of their participation varies according to the patient's endotype. Anti-inflammatory medications may modify the natural history and progression of COPD. However, since airway inflammation in COPD is relatively resistant to corticosteroid therapy, innovative pharmacological anti-inflammatory approaches are required. The heterogeneity of inflammatory cells and mediators in annethe different COPD endo-phenotypes requires the development of specific pharmacologic agents. Indeed, over the past two decades, several mechanisms that influence the influx and/or activity of inflammatory cells in the airways and lung parenchyma have been identified. Several of these molecules have been tested in vitro models and in vivo in laboratory animals, but only a few have been studied in humans. Although early studies have not been encouraging, useful information emerged suggesting that some of these agents may need to be further tested in specific subgroups of patients, hopefully leading to a more personalized approach to treating COPD.

Iron and mitochondria in the susceptibility, pathogenesis and progression of COPD

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease characterised by airflow limitation, chronic bronchitis, emphysema and airway remodelling. Cigarette smoke is considered the primary risk factor for the development of COPD; however, genetic factors, host responses and infection also play an important role. Accumulating evidence highlights a role for iron dyshomeostasis and cellular iron accumulation in the lung as a key contributing factor in the development and pathogenesis of COPD. Recent studies have also shown that mitochondria, the central players in cellular iron utilisation, are dysfunctional in respiratory cells in individuals with COPD, with alterations in mitochondrial bioenergetics and dynamics driving disease progression. Understanding the molecular mechanisms underlying the dysfunction of mitochondria and cellular iron metabolism in the lung may unveil potential novel investigational avenues and therapeutic targets to aid in the treatment of COPD.

Multifaceted Roles of Chemokine C-X-C Motif Ligand 7 in Inflammatory Diseases and Cancer

Over recent years, C-X-C motif ligand 7 (CXCL7) has received widespread attention as a chemokine involved in inflammatory responses. Abnormal production of the chemokine CXCL7 has been identified in different inflammatory diseases; nevertheless, the exact role of CXCL7 in the pathogenesis of inflammatory diseases is not fully understood. Persistent infection or chronic inflammation can induce tumorigenesis and progression. Previous studies have shown that the pro-inflammatory chemokine CXCL7 is also expressed by malignant tumor cells and that binding of CXCL7 to its cognate receptors C-X-C chemokine receptor 1 (CXCR1) and C-X-C chemokine receptor 2 (CXCR2) can influence tumor biological behavior (proliferation, invasion, metastasis, and tumor angiogenesis) in an autocrine and paracrine manner. CXCL7 and its receptor CXCR1/CXCR2, which are aberrantly expressed in tumors, may represent new targets for clinical tumor immunotherapy.

Emerging role of exosomes in the pathology of chronic obstructive pulmonary diseases; destructive and therapeutic properties

Chronic obstructive pulmonary disease (COPD) is known as the third leading cause of human death globally. Enhanced chronic inflammation and pathological remodeling are the main consequences of COPD, leading to decreased life span. Histological and molecular investigations revealed that prominent immune cell infiltration and release of several cytokines contribute to progressive chronic remodeling. Recent investigations have revealed that exosomes belonging to extracellular vesicles are involved in the pathogenesis of COPD. It has been elucidated that exosomes secreted from immune cells are eligible to carry numerous pro-inflammatory factors exacerbating the pathological conditions. Here, in this review article, we have summarized various and reliable information about the negative role of immune cell-derived exosomes in the remodeling of pulmonary tissue and airways destruction in COPD patients.

Classes of drugs that target the cellular components of inflammation under clinical development for COPD

INTRODUCTION

The persistent inflammation that characterizes COPD and affects its natural course also impacting on symptoms has prompted research to find molecules that can regulate the inflammatory process but still available anti-inflammatory therapies provide little or no benefit in COPD patients. Consequently, numerous anti-inflammatory molecules that are effective in animal models of COPD have been or are being evaluated in humans.

AREAS COVERED

In this article we describe several classes of drugs that target the cellular components of inflammation under clinical development for COPD.

EXPERT OPINION

Although the results of many clinical trials with new molecules have often been disappointing, several studies are underway to investigate whether some of these molecules may be effective in treating specific subgroups of COPD patients. Indeed, the current perspective is to apply a more personalized treatment to the patient. This means being able to better define the patient's inflammatory state and treat it in a targeted manner. Unfortunately, the difficulty in translating encouraging experimental data into human clinical trials, the redundancy in the effects induced by signal-transmitting substances and the nonspecific effects of many classes that are undergoing clinical trials, do not yet allow specific inflammatory cell types to be targeted.

COPD Is Associated with Elevated IFN-β Production by Bronchial Epithelial Cells Infected with RSV or hMPV

IFN treatment may be a viable option for treating COPD exacerbations based on evidence of IFN deficiency in COPD. However, in vitro studies have used primarily influenza and rhinoviruses to investigate IFN responses. This study aims to investigate the susceptibility to infection and IFN response of primary bronchial epithelial cells (BECs) from COPD donors to infection with RSV and hMPV. BECs from five COPD and five healthy donors were used to establish both submerged monolayer and well-differentiated (WD) cultures. Two isolates of both RSV and hMPV were used to infect cells. COPD was not associated with elevated susceptibility to infection and there was no evidence of an intrinsic defect in IFN production in either cell model to either virus. Conversely, COPD was associated with significantly elevated IFN-β production in response to both viruses in both cell models. Only in WD-BECs infected with RSV was elevated IFN-β associated with reduced viral shedding. The role of elevated epithelial cell IFN-β production in the pathogenesis of COPD is not clear and warrants further investigation. Viruses vary in the responses that they induce in BECs, and so conclusions regarding antiviral responses associated with disease cannot be made based on single viral infections.

Non-typeable Haemophilus influenzae chronic colonization in chronic obstructive pulmonary disease (COPD)

Haemophilus influenzae is the most common cause of bacterial infection in the lungs of chronic obstructive pulmonary disease (COPD) patients and contributes to episodes of acute exacerbation which are associated with increased hospitalization and mortality. Due to the ability of H. influenzae to adhere to host epithelial cells, initial colonization of the lower airways can progress to a persistent infection and biofilm formation. This is characterized by changes in bacterial behaviour such as reduced cellular metabolism and the production of an obstructive extracellular matrix (ECM). Herein we discuss the multiple mechanisms by which H. influenzae contributes to the pathogenesis of COPD. In particular, mechanisms that facilitate bacterial adherence to host airway epithelial cells, biofilm formation, and microbial persistence through immune system evasion and antibiotic tolerance will be discussed.

COVID-19 Susceptibility in chronic obstructive pulmonary disease

In barely nine months, the pandemic known as COVID-19 has spread over 200 countries, affecting more than 22 million people and causing over than 786 000 deaths. Elderly people and patients with previous comorbidities such as hypertension and diabetes are at an increased risk to suffer a poor prognosis after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although the same could be expected from patients with chronic obstructive pulmonary disease (COPD), current epidemiological data are conflicting. This could lead to a reduction of precautionary measures in these patients, in the context of a particularly complex global health crisis. Most COPD patients have a long history of smoking or exposure to other harmful particles or gases, capable of impairing pulmonary defences even years after the absence of exposure. Moreover, COPD is characterized by an ongoing immune dysfunction, which affects both pulmonary and systemic cellular and molecular inflammatory mediators. Consequently, increased susceptibility to viral respiratory infections have been reported in COPD, often worsened by bacterial co-infections and leading to serious clinical outcomes. The present paper is an up-to-date review that discusses the available research regarding the implications of coronavirus infection in COPD. Although validation in large studies is still needed, COPD likely increases SARS-CoV-2 susceptibility and increases COVID-19 severity. Hence, specific mechanisms to monitor and assess COPD patients should be addressed in the current pandemic.

DNA Methylation: A Potential Biomarker of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a serious public health concern worldwide. By 2040, 4.41 million people are estimated to expire annually due to COPD. However, till date, it has remained difficult to alter the activity or progress of the disease through treatment. In order to address this issue, the best way would be to find biomarkers and new therapeutic targets for COPD. DNA methylation (DNAm) may be a potential biomarker for disease prevention, diagnosis, and prognosis, and its reversibility further makes it a potential drug design target in COPD. In this review, we aimed to explore the role of DNAm as biomarkers and disease mediators in different tissue samples from patients with COPD.

Losartan does not inhibit cigarette smoke-induced lung inflammation in mice

Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease largely caused by cigarette smoking (CS) and is characterized by lung inflammation and airflow limitation that is not fully reversible. Approximately 50% of people with COPD die of a cardiovascular comorbidity and current pharmacological strategies provide little benefit. Therefore, drugs that target the lung and the cardiovascular system concurrently may be an advantageous therapeutic strategy. The aim of this study was to see whether losartan, an angiotensin-II AT1a receptor antagonist widely used to treat hypertension associated with cardiovascular disease, protects against CS-induced lung inflammation in mice. Male BALB/c mice were exposed to CS for 8 weeks and treated with either losartan (30 mg/kg) or vehicle daily. Mice were euthanized and bronchoalveolar lavage fluid (BALF) inflammation, and whole lung cytokine, chemokine and protease mRNA expression assessed. CS caused significant increases in BALF total cells, macrophages, neutrophils and whole lung IL-6, TNF-α, CXCL-1, IL-17A and MMP12 mRNA expression compared to sham-exposed mice. However, losartan only reduced CS-induced increases in IL-6 mRNA expression. Angiotensin-II receptor expression was reduced in lung tissue from CS-exposed mice. In conclusion, losartan did not inhibit CS-induced BALF cellularity despite reducing whole lung IL-6 mRNA and Ang-II receptor expression.

The Interplay Between Immune Response and Bacterial Infection in COPD: Focus Upon Non-typeable Haemophilus influenzae

Chronic obstructive pulmonary disease (COPD) is a debilitating respiratory disease and one of the leading causes of morbidity and mortality worldwide. It is characterized by persistent respiratory symptoms and airflow limitation due to abnormalities in the lower airway following consistent exposure to noxious particles or gases. Acute exacerbations of COPD (AECOPD) are characterized by increased cough, purulent sputum production, and dyspnea. The AECOPD is mostly associated with infection caused by common cold viruses or bacteria, or co-infections. Chronic and persistent infection by non-typeable Haemophilus influenzae (NTHi), a Gram-negative coccobacillus, contributes to almost half of the infective exacerbations caused by bacteria. This is supported by reports that NTHi is commonly isolated in the sputum from COPD patients during exacerbations. Persistent colonization of NTHi in the lower airway requires a plethora of phenotypic adaptation and virulent mechanisms that are developed over time to cope with changing environmental pressures in the airway such as host immuno-inflammatory response. Chronic inhalation of noxious irritants in COPD causes a changed balance in the lung microbiome, abnormal inflammatory response, and an impaired airway immune system. These conditions significantly provide an opportunistic platform for NTHi colonization and infection resulting in a "vicious circle." Episodes of large inflammation as the consequences of multiple interactions between airway immune cells and NTHi, accumulatively contribute to COPD exacerbations and may result in worsening of the clinical status. In this review, we discuss in detail the interplay and crosstalk between airway immune residents and NTHi, and their effect in AECOPD for better understanding of NTHi pathogenesis in COPD patients.

Dysregulated Functions of Lung Macrophage Populations in COPD

Chronic obstructive pulmonary disease (COPD) is a diverse respiratory disease characterised by bronchiolitis, small airway obstruction, and emphysema. Innate immune cells play a pivotal role in the disease's progression, and in particular, lung macrophages exploit their prevalence and strategic localisation to orchestrate immune responses. To date, alveolar and interstitial resident macrophages as well as blood monocytes have been described in the lungs of patients with COPD contributing to disease pathology by changes in their functional repertoire. In this review, we summarise recent evidence from human studies and work with animal models of COPD with regard to altered functions of each of these myeloid cell populations. We primarily focus on the dysregulated capacity of alveolar macrophages to secrete proinflammatory mediators and proteases, induce oxidative stress, engulf microbes and apoptotic cells, and express surface and intracellular markers in patients with COPD. In addition, we discuss the differences in the responses between alveolar macrophages and interstitial macrophages/monocytes in the disease and propose how the field should advance to better understand the implications of lung macrophage functions in COPD.

Cellular and molecular mechanisms of asthma and COPD

Asthma and chronic obstructive pulmonary disease (COPD) both cause airway obstruction and are associated with chronic inflammation of the airways. However, the nature and sites of the inflammation differ between these diseases, resulting in different pathology, clinical manifestations and response to therapy. In this review, the inflammatory and cellular mechanisms of asthma and COPD are compared and the differences in inflammatory cells and profile of inflammatory mediators are highlighted. These differences account for the differences in clinical manifestations of asthma and COPD and their response to therapy. Although asthma and COPD are usually distinct, there are some patients who show an overlap of features, which may be explained by the coincidence of two common diseases or distinct phenotypes of each disease. It is important to better understand the underlying cellular and molecular mechanisms of asthma and COPD in order to develop new treatments in areas of unmet need, such as severe asthma, curative therapy for asthma and effective anti-inflammatory treatments for COPD.

Paradigms in chronic obstructive pulmonary disease: phenotypes, immunobiology, and therapy with a focus on vascular disease

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous syndrome that represents a major global health burden. COPD phenotypes have recently emerged based on large cohort studies addressing the need to better characterize the syndrome. Though comprehensive phenotyping is still at an early stage, factors such as ethnicity and radiographic, serum, and exhaled breath biomarkers have shown promise. COPD is also an immunological disease where innate and adaptive immune responses to the environment and tobacco smoke are altered. The frequent overlap between COPD and other systemic diseases, such as cardiovascular disease, has influenced COPD therapy, and treatments for both conditions may lead to improved patient outcomes. Here, we discuss current paradigms that center on improving the definition of COPD, understanding the immunological overlap between COPD and vascular inflammation, and the treatment of COPD-with a focus on comorbid cardiovascular disease.

The main rhinovirus respiratory tract adhesion site (ICAM-1) is upregulated in smokers and patients with chronic airflow limitation (CAL)

BACKGROUND

ICAM-1 is a major receptor for ~60% of human rhinoviruses, and non-typeable Haemophilus influenzae, two major pathogens in COPD. Increased cell-surface expression of ICAM-1 in response to tobacco smoke exposure has been suggested. We have investigated epithelial ICAM-1 expression in both the large and small airways, and lung parenchyma in smoking-related chronic airflow limitation (CAL) patients.

METHODS

We evaluated epithelial ICAM-1 expression in resected lung tissue: 8 smokers with normal spirometry (NLFS); 29 CAL patients (10 small-airway disease; 9 COPD-smokers; 10 COPD ex-smokers); Controls (NC): 15 normal airway/lung tissues. Immunostaining with anti-ICAM-1 monoclonal antibody was quantified with computerized image analysis. The percent and type of cells expressing ICAM-1 in large and small airway epithelium and parenchyma were enumerated, plus percentage of epithelial goblet and submucosal glands positive for ICAM- 1.

RESULTS

A major increase in ICAM-1 expression in epithelial cells was found in both large (p < 0.006) and small airways (p < 0.004) of CAL subjects compared to NC, with NLFS being intermediate. In the CAL group, both basal and luminal areas stained heavily for ICAM-1, so did goblet cells and sub-mucosal glands, however in either NC or NLFS subjects, only epithelial cell luminal surfaces stained. ICAM-1 expression on alveolar pneumocytes (mainly type II) was slightly increased in CAL and NLFS (p < 0.01). Pack-years of smoking correlated with ICAM-1 expression (r = 0.49; p < 0.03).

CONCLUSION

Airway ICAM-1 expression is markedly upregulated in CAL group, which could be crucial in rhinoviral and NTHi infections. The parenchymal ICAM-1 is affected by smoking, with no further enhancement in CAL subjects.

Endocan and the respiratory system: a review

Endocan, formerly called endothelial cell-specific molecule 1, is an endothelial cell-associated proteoglycan that is preferentially expressed by renal and pulmonary endothelium. It is upregulated by proangiogenic molecules as well as by pro-inflammatory cytokines, and since it reflects endothelial activation and dysfunction, it is regarded as a novel tissue and blood-based relevant biomarker. As such, it is increasingly being researched and evaluated in a wide spectrum of healthy and disease pathophysiological processes. Here, we review the present scientific knowledge on endocan, with emphasis on the evidence that underlines its possible clinical value as a prognostic marker in several malignant, inflammatory and obstructive disorders of the respiratory system.

Pathogenesis of Viral Infection in Exacerbations of Airway Disease

Chronic airway diseases are a significant cause of morbidity and mortality worldwide, and their prevalence is predicted to increase in the future. Respiratory viruses are the most common cause of acute pulmonary infection, and there is clear evidence of their role in acute exacerbations of inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease. Studies have reported impaired host responses to virus infection in these diseases, and a better understanding of the mechanisms of these abnormal immune responses has the potential to lead to the development of novel therapeutic targets for virus-induced exacerbations. The aim of this article is to review the current knowledge regarding the role of viruses and immune modulation in acute exacerbations of chronic pulmonary diseases and to discuss exciting areas for future research and novel treatments.

Inflammatory mechanisms in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation affecting predominantly the lung parenchyma and peripheral airways that results in largely irreversible and progressive airflow limitation. This inflammation is characterized by increased numbers of alveolar macrophages, neutrophils, T lymphocytes (predominantly TC1, TH1, and TH17 cells), and innate lymphoid cells recruited from the circulation. These cells and structural cells, including epithelial and endothelial cells and fibroblasts, secrete a variety of proinflammatory mediators, including cytokines, chemokines, growth factors, and lipid mediators. Although most patients with COPD have a predominantly neutrophilic inflammation, some have an increase in eosinophil counts, which might be orchestrated by TH2 cells and type 2 innate lymphoid cells though release of IL-33 from epithelial cells. These patients might be more responsive to corticosteroids and bronchodilators. Oxidative stress plays a key role in driving COPD-related inflammation, even in ex-smokers, and might result in activation of the proinflammatory transcription factor nuclear factor κB (NF-κB), impaired antiprotease defenses, DNA damage, cellular senescence, autoantibody generation, and corticosteroid resistance though inactivation of histone deacetylase 2. Systemic inflammation is also found in patients with COPD and can worsen comorbidities, such as cardiovascular diseases, diabetes, and osteoporosis. Accelerated aging in the lungs of patients with COPD can also generate inflammatory protein release from senescent cells in the lung. In the future, it will be important to recognize phenotypes of patients with optimal responses to more specific therapies, and development of biomarkers that identify the therapeutic phenotypes will be important.

The role of viral infections in exacerbations of chronic obstructive pulmonary disease and asthma

Asthma and chronic obstructive pulmonary disease (COPD) are major causes of global morbidity and mortality worldwide. The clinical course of both asthma and COPD are punctuated by the occurrence of exacerbations, acute events characterized by increased symptoms and airflow obstruction. Exacerbations contribute most of the morbidity, mortality and excess healthcare costs associated with both asthma and COPD. COPD and asthma exacerbations are frequently associated with respiratory virus infections and this has led to an intense research focus into the mechanisms of virus-induced exacerbations over the past decade. Current therapies are effective in reducing chronic symptoms but are less effective in preventing exacerbations, particularly in COPD. Understanding the mechanisms of virus-induced exacerbation will lead to the development of new targeted therapies that can reduce the burden of virus-induced exacerbations. In this review we discuss current knowledge of virus-induced exacerbations of asthma and COPD with a particular focus on mechanisms, human studies, virus-bacteria interactions and therapeutic advances.

N-acetylcysteine in COPD: why, how, and when?

Oxidants have long been recognized to have an important role in the pathogenesis of COPD, and in this cigarette smoke has a strong responsibility, because it generates a conspicuous amount of oxidant radicals able to modify the structure of the respiratory tract and to enhance several mechanisms that sustain lung inflammation in COPD. In fact, oxidative stress is highly increased in COPD and natural antioxidant capacities, mainly afforded by reduced glutathione, are often overcome. Thus an exogenous supplementation of antioxidant compounds is mandatory to at least partially counteract the oxidative stress. For this purpose N-acetylcysteine has great potentialities due to its capacity of directly contrasting oxidants with its free thiols, and to the possibility it has of acting as donor of cysteine precursors aimed at glutathione restoration. Many studies in vitro and in vivo have already demonstrated the antioxidant capacity of NAC. Many clinical studies have long been performed to explore the efficacy of NAC in COPD with altern results, especially when the drug was used at very low dosage and/or for a short period of time. More recently, several trials have been conducted to verify the appropriateness of using high-dose NAC in COPD, above all to decrease the exacerbations rate. The results have been encouraging, even if some of the data come from the most widely sized trials that have been conducted in Chinese populations. Although other evidence should be necessary to confirm the results in other populations of patients, high-dose oral NAC nevertheless offers interesting perspectives as add-on therapy for COPD patients.

Senescence-associated secretory phenotype and its possible role in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major disease of the lungs. It primarily occurs after a prolonged period of cigarette smoking. Chronic inflammation of airways and the alveolar space as well as lung tissue destruction are the hallmarks of COPD. Recently it has been shown that cellular senescence might play a role in the pathogenesis of COPD. Cellular senescence comprises signal transduction program, leading to irreversible cell cycle arrest. The growth arrest in senescence can be triggered by many different mechanisms, including DNA damage and its recognition by cellular sensors, leading to the activation of cell cycle checkpoint responses and activation of DNA repair machinery. Senescence can be induced by several genotoxic factors apart from telomere attrition. When senescence induction is based on DNA damage, senescent cells display a unique phenotype, which has been termed "senescence-associated secretory phenotype" (SASP). SASP may be an important driver of chronic inflammation and therefore may be part of a vicious cycle of inflammation, DNA damage, and senescence. This research perspective aims to showcase cellular senescence with relevance to COPD and the striking similarities between the mediators and secretory phenotype in COPD and SASP.

The association of plasma biomarkers with computed tomography-assessed emphysema phenotypes

Rationale

Chronic obstructive pulmonary disease (COPD) is a phenotypically heterogeneous disease. In COPD, the presence of emphysema is associated with increased mortality and risk of lung cancer. High resolution computed tomography (HRCT) scans are useful in quantifying emphysema but are associated with radiation exposure and high incidence of false positive findings (i.e., nodules). Using a comprehensive biomarker panel, we sought to determine if there was a peripheral blood biomarker signature of emphysema.

Methods

114 plasma biomarkers were measured using a custom assay in 588 individuals enrolled in the COPDGene study. Quantitative emphysema measurements included percent low lung attenuation (%LAA) ≤ −950 HU, ≤ − 910 HU and mean lung attenuation at the 15^th percentile on lung attenuation curve (LP15A). Multiple regression analysis was performed to determine plasma biomarkers associated with emphysema independent of covariates age, gender, smoking status, body mass index and FEV₁. The findings were subsequently validated using baseline blood samples from a separate cohort of 388 subjects enrolled in the Treatment of Emphysema with a Selective Retinoid Agonist (TESRA) study.

Results

Regression analysis identified multiple biomarkers associated with CT-assessed emphysema in COPDGene, including advanced glycosylation end-products receptor (AGER or RAGE, p < 0.001), intercellular adhesion molecule 1 (ICAM, p < 0.001), and chemokine ligand 20 (CCL20, p < 0.001). Validation in the TESRA cohort revealed significant associations with RAGE, ICAM1, and CCL20 with radiologic emphysema (p < 0.001 after meta-analysis). Other biomarkers that were associated with emphysema include CDH1, CDH 13 and SERPINA7, but were not available for validation in the TESRA study. Receiver operating characteristics analysis demonstrated a benefit of adding a biomarker panel to clinical covariates for detecting emphysema, especially in those without severe airflow limitation (AUC 0.85).

Conclusions

Our findings, suggest that a panel of blood biomarkers including sRAGE, ICAM1 and CCL20 may serve as a useful surrogate measure of emphysema, and when combined with clinical covariates, may be useful clinically in predicting the presence of emphysema compared to just using covariates alone, especially in those with less severe COPD. Ultimately biomarkers may shed light on disease pathogenesis, providing targets for new treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0127-9) contains supplementary material, which is available to authorized users.

Capsosiphon fulvescens glycoprotein inhibits AGS gastric cancer cell proliferation by downregulating Wnt-1 signaling

Previously, we examined various apoptosis pathways in the AGS gastric cancer cell line using Capsosiphon fulvescens glycoprotein (Cf-GP). In this study, we focused on the downregulation of the Wnt-1 signaling pathway and cell cycle arrest. Upregulation of the Wnt signaling pathway has been observed in various cancer cells. The Wnt signal ligand acts in both canonical and non-canonical pathways. Among them, Wnt-1 was dependent on the canonical pathway. Here, we show inhibition of Wnt-1 signaling, β-catenin and transcription factors in AGS cells via Cf-GP. First, we examined the Frizzled receptor and Wnt-1 signal-related proteins including Axin, LRP, β-catenin, APC and GSK-3β. In addition, the expression levels of transcription factors Tcf/LEF were determined by western blot analysis and RT-PCR. Based on the data, we confirmed downregulation of the Wnt-1 signaling pathway by Cf-GP. Also, we determined the expression levels of cell cycle-related proteins cyclin D and c-myc, and looked for cell cycle arrest by cell cycle test analysis. We found that AGS cells arrested in the G0/G1 phase by Cf-GP. These results provide a mechanism of AGS cell inhibition through the downregulation of Wnt-1 signaling by Cf-GP.

Mechanisms and impact of the frequent exacerbator phenotype in chronic obstructive pulmonary disease

Exacerbations of chronic obstructive pulmonary disease (COPD) are important events that carry significant consequences for patients. Some patients experience frequent exacerbations, and are now recognized as a distinct clinical subgroup, the 'frequent exacerbator' phenotype. This is relatively stable over time, occurs across disease severity, and is associated with poorer health outcomes. These patients are therefore a priority for research and treatment. The pathophysiology underlying the frequent exacerbator phenotype is complex, with increased airway and systemic inflammation, dynamic lung hyperinflation, changes in lower airway bacterial colonization and a possible increased susceptibility to viral infection. Frequent exacerbators are also at increased risk from comorbid extrapulmonary diseases including cardiovascular disease, gastroesophageal reflux, depression, osteoporosis and cognitive impairment. Overall these patients have poorer health status, accelerated forced expiratory volume over 1 s (FEV1) decline, worsened quality of life, and increased hospital admissions and mortality, contributing to increased exacerbation susceptibility and perpetuation of the frequent exacerbator phenotype. This review article sets out the definition and importance of the frequent exacerbator phenotype, with a detailed examination of its pathophysiology, impact and interaction with other comorbidities.

Inflammation and immune response in COPD: where do we stand?

Increasing evidence indicates that chronic inflammatory and immune responses play key roles in the development and progression of COPD. Recent data provide evidence for a role in the NLRP3 inflammasome in the airway inflammation observed in COPD. Cigarette smoke activates innate immune cells by triggering pattern recognition receptors (PRRs) to release “danger signal”. These signals act as ligands to Toll-like receptors (TLRs), triggering the production of cytokines and inducing innate inflammation. In smokers who develop COPD there appears to be a specific pattern of inflammation in the airways and parenchyma as a result of both innate and adaptive immune responses, with the predominance of CD8+ and CD4+ cells, and in the more severe disease, with the presence of lymphoid follicles containing B lymphocytes and T cells. Furthermore, viral and bacterial infections interfere with the chronic inflammation seen in stable COPD and exacerbations via pathogen-associated molecular patterns (PAMPs). Finally, autoimmunity is another novel aspect that may play a critical role in the pathogenesis of COPD. This review is un update of the currently discussed roles of inflammatory and immune responses in the pathogenesis of COPD.

Surfactant protein D, soluble intercellular adhesion molecule-1 and high-sensitivity C-reactive protein as biomarkers of chronic obstructive pulmonary disease

OBJECTIVE

The aim of this study was to estimate the serum levels of surfactant protein D (SP-D), soluble intercellular adhesion molecule-1 (sICAM-1), and high-sensitivity C-reactive protein (hs-CRP) in patients with chronic obstructive pulmonary disease (COPD) and to assess the correlation of these indices with COPD severity.

SUBJECTS AND METHODS

This analytic cross-sectional study was carried out on 64 COPD male patients, and 26 apparently healthy age-matched males as a control. Chest X-ray, spirometry and arterial blood gases were done for only COPD patients. Serum levels of SP-D, sICAM-1 and hs-CRP were determined by enzyme-linked immunosorbent assay in both patient and control groups.

RESULTS

The serum levels of SP-D, sICAM-1 and hs-CRP were significantly higher in COPD patients than controls (p < 0.001 for each). Also, these biomarkers were significantly higher in stages III and IV compared to either stage I or II (p < 0.01 for each). SP-D was significantly positively correlated with sICAM-1 and hs-CRP (r = 515, p < 0.001; r = 501, p < 0.001, respectively) and negatively correlated with PaO2 (r = -0.651, p < 0.001) and all parameters of spirometry.

CONCLUSION

SP-D, sICAM and hs-CRP were significantly higher in COPD patients in comparison with controls. Moreover, SP-D, sICAM-1, and hs-CRP were significantly negatively correlated with FEV1%. Accordingly, estimation of these biochemical indices may be used as biomarkers for assessment of COPD severity.

Adhesion molecules in subjects with COPD and healthy non-smokers: a cross sectional parallel group study

Background

The aim of the study was to investigate how the expression of adhesion molecules changes as neutrophils migrate from the circulation to the lung and if these changes differ between non-smoking subjects and smokers with and without COPD.

Methods

Non-smoking healthy subjects (n=22), smokers without (n=21) and with COPD (n=18) were included. Neutrophils from peripheral blood, sputum and bronchial biopsies were analysed for cell surface expression of adhesion molecules (CD11b, CD62L, CD162). Serum, sputum supernatant and BAL-fluid were analysed for soluble adhesion molecules (ICAM-1, -3, E-selectin, P-selectin, VCAM-1, PECAM-1).

Results

Expression of CD11b was increased on circulating neutrophils from smokers with COPD. It was also increased on sputum neutrophils in both smokers groups, but not in non-smokers, as compared to circulating neutrophils.

Serum ICAM-1 was higher in the COPD group compared to the other two groups (p<0.05) and PECAM-1 was lower in smokers without COPD than in non-smoking controls and the COPD group (p<0.05). In BAL-fluid ICAM-1 was lower in the COPD group than in the other groups (p<0.05).

Conclusions

Thus, our data strongly support the involvement of a systemic component in COPD and demonstrate that in smokers neutrophils are activated to a greater extent at the point of transition from the circulation into the lungs than in non-smokers.

Adhesion molecules, endothelin-1 and lung function in seven population-based cohorts

CONTEXT

Endothelial function is abnormal in chronic obstructive pulmonary disease (COPD); whether endothelial dysfunction causes COPD is unknown.

OBJECTIVE

Test associations of endothelial biomarkers with FEV1 using instrumental variables.

METHODS

Among 26 907 participants with spirometry, ICAM-1, P-selectin, E-selectin and endothelin-1 were measured in subsets.

RESULTS

ICAM-1 and P-selectin were inversely associated with FEV1 among European-Americans (-29 mL and -34 mL per standard deviation of log-transformed biomarker, p < 0.001), as was endothelin-1 among African-Americans (-22 mL, p = 0.008). Genetically-estimated ICAM-1 and P-selectin were not significantly associated with FEV1. The instrumental variable for endothelin-1 was non-informative.

CONCLUSION

Although ICAM-1, P-selectin and endothelin-1 were inversely associated with FEV1, associations for ICAM-1 and P-selectin do not appear causal.

Genome-wide methylation profiling of the bronchial mucosa of asthmatics: relationship to atopy

Background

Asthma is a common respiratory disease that is characterized by bronchial hyperresponsiveness and airway obstruction due to chronic airway inflammation. Atopic asthma is a typical IgE-mediated disease in which the enhanced production of IgE is driven by the activation of Th2 cells, which release a distinct pattern of cytokines, including interleukin 4 (IL4) and IL3, in response to specific antigen presentation. To evaluate the methylation status of the whole genomes of bronchial mucosa tissues from subjects who lacked or had sensitization to Dermatophagoides farina (Df) and Dermatophagoides pteronyssinus (Dp).

Methods

The genome-wide DNA methylation levels in the bronchial mucosa tissues of atopic asthmatics (N = 10), non-atopic asthmatics (N = 7), and normal controls (N = 7) were examined using microarrays.

Results

In the bronchial mucosa of atopic asthmatics, hypermethylation was detected at 6 loci in 6 genes, while hypomethylation was detected at 49 loci in 48 genes compared to those of non-atopic asthmatics. Genes that were assigned the ontologies of multicellular organismal process, response to organic substance, hormone metabolic process, and growth factor receptor binding were hypomethylated. The methylation levels in the mucosa of asthmatics and normal controls were similar.

Conclusions

The bronchial mucosa of asthmatics who are atopic to Df or Dp have characteristic methylation patterns for 52 genes. The genes and pathways identified in the present study may be associated with the presence of atopy in asthmatics and therefore represent attractive targets for future research.

COPD exacerbations: causes, prevention, and treatment

The mechanisms of chronic obstructive pulmonary disease exacerbation are complex. Respiratory viruses (in particular rhinovirus) and bacteria play a major role in the cause of these events. A distinct group of patients seems susceptible to frequent exacerbations, irrespective of disease severity, and this phenotype is stable over time. Many current therapeutic strategies help reduce exacerbation frequency. Further work is required to develop novel anti-inflammatory therapies for exacerbation prevention and treatment. This article focuses on the cause of chronic obstructive pulmonary disease exacerbations, and the current preventative and acute interventions available.

Inhaled pan-selectin antagonist Bimosiamose attenuates airway inflammation in COPD

Selectins, a family of cell adhesion molecules, are involved in leukocyte extravasation to sites of inflammation. We investigated the safety and efficacy of the inhaled pan-selectin antagonist Bimosiamose in patients with chronic obstructive pulmonary disease (COPD). 77 COPD patients (mean forced expiratory volume in 1 s, 57% pred.) were enrolled in a cross-over, double-blind, randomized, Placebo-controlled, multi-center trial. Bimosiamose (10 mg) or Placebo was inhaled twice daily via the breath actuated nebulizer Akita2 Apixneb™ for 28 days on top of standard bronchodilator therapy. Efficacy was assessed by measurement of inflammatory parameters in induced sputum (differential cell count, interleukin-8, matrix-metalloproteinase-9, myeloperoxidase) and lung function at day 28 of both treatment periods. The total adverse event ratio of Bimosiamose compared to Placebo treatment was balanced. Compared to Placebo, treatment with Bimosiamose led to a decrease of the interleukin-8 concentration (-9.49 ng/mL, 95%CI -18.8 to -2.7 ng/mL, p = 0.008), for the neutrophil count a difference of -0.368 × 10(6) cells/mL (95%CI -1.256 to 0.407 × 10(6)/mL, p = 0.313) was found. The macrophage count decreased by -0.200 × 10(6) cells/mL (95%CI -0.365 to -0.044 × 10(6) cells/mL, p = 0.012). Most lung function parameters showed a small numeric increase. Inhalation of Bimosiamose for 28 days was safe and well tolerated in patients with COPD. It led to an attenuation of airway inflammation (EudraCT 2009-017257-35; NCT ID: NCT01108913).

Lung microbiology and exacerbations in COPD

Chronic obstructive pulmonary disease (COPD) is the most common chronic respiratory condition in adults and is characterized by progressive airflow limitation that is not fully reversible. The main etiological agents linked with COPD are cigarette smoking and biomass exposure but respiratory infection is believed to play a major role in the pathogenesis of both stable COPD and in acute exacerbations. Acute exacerbations are associated with more rapid decline in lung function and impaired quality of life and are the major causes of morbidity and mortality in COPD. Preventing exacerbations is a major therapeutic goal but currently available treatments for exacerbations are not very effective. Historically, bacteria were considered the main infective cause of exacerbations but with the development of new diagnostic techniques, respiratory viruses are also frequently detected in COPD exacerbations. This article aims to provide a state-of-the art review of current knowledge regarding the role of infection in COPD, highlight the areas of ongoing debate and controversy, and outline emerging technologies and therapies that will influence future diagnostic and therapeutic pathways in COPD.

COPD exacerbations: causes, prevention, and treatment

The mechanisms of COPD exacerbation are complex. Respiratory viruses (in particular rhinovirus) and bacteria play a major role in the causative etiology of COPD exacerbations. In some patients, noninfective environmental factors may also be important. Data recently published from a large observational study identified a phenotype of patients more susceptible to frequent exacerbations. Many current therapeutic strategies can reduce exacerbation frequency. Future studies may target the frequent exacerbator phenotype, or those patients colonized with potential bacterial pathogens, for such therapies as long-term antibiotics, thus preventing exacerbations by decreasing bacterial load or preventing new strain acquisition in the stable state. Respiratory viral infections are also an important therapeutic target for COPD. Further work is required to develop new anti-inflammatory agents for exacerbation prevention, and novel acute treatments to improve outcomes at exacerbation.

Leukocytes are recruited through the bronchial circulation to the lung in a spontaneously hypertensive rat model of COPD

Chronic obstructive pulmonary disease (COPD) kills approximately 2.8 million people each year, and more than 80% of COPD cases can be attributed to smoking. Leukocytes recruited to the lung contribute to COPD pathology by releasing reactive oxygen metabolites and proteolytic enzymes. In this work, we investigated where leukocytes enter the lung in the early stages of COPD in order to better understand their effect as a contributor to the development of COPD. We simultaneously evaluated the parenchyma and airways for neutrophil accumulation, as well as increases in the adhesion molecules and chemokines that cause leukocyte recruitment in the early stages of tobacco smoke induced lung disease. We found neutrophil accumulation and increased expression of adhesion molecules and chemokines in the bronchial blood vessels that correlated with the accumulation of leukocytes recovered from the lung. The expression of adhesion molecules and chemokines in other vascular beds did not correlate with leukocytes recovered in bronchoalveolar lavage fluid (BALF). These data strongly suggest leukocytes are recruited in large measure through the bronchial circulation in response to tobacco smoke. Our findings have important implications for understanding the etiology of COPD and suggest that pharmaceuticals designed to reduce leukocyte recruitment through the bronchial circulation may be a potential therapy to treat COPD.

Viruses exacerbating chronic pulmonary disease: the role of immune modulation

Chronic pulmonary diseases are a major cause of morbidity and mortality and their impact is expected to increase in the future. Respiratory viruses are the most common cause of acute respiratory infections and it is increasingly recognized that respiratory viruses are a major cause of acute exacerbations of chronic pulmonary diseases such as asthma, chronic obstructive pulmonary disease and cystic fibrosis. There is now increasing evidence that the host response to virus infection is dysregulated in these diseases and a better understanding of the mechanisms of abnormal immune responses has the potential to lead to the development of new therapies for virus-induced exacerbations. The aim of this article is to review the current knowledge regarding the role of viruses and immune modulation in chronic pulmonary diseases and discuss avenues for future research and therapeutic implications.

Variable DNA methylation is associated with chronic obstructive pulmonary disease and lung function

RATIONALE

Chronic obstructive pulmonary disease (COPD) is associated with local (lung) and systemic (blood) inflammation and manifestations. DNA methylation is an important regulator of gene transcription, and global and specific gene methylation marks may vary with cigarette smoke exposure.

OBJECTIVES

To perform a comprehensive assessment of methylation marks in DNA from subjects well phenotyped for nonneoplastic lung disease.

METHODS

We conducted array-based methylation screens, using a test-replication approach, in two family-based cohorts (n = 1,085 and 369 subjects).

MEASUREMENTS AND MAIN RESULTS

We observed 349 CpG sites significantly associated with the presence and severity of COPD in both cohorts. Seventy percent of the associated CpG sites were outside of CpG islands, with the majority of CpG sites relatively hypomethylated. Gene ontology analysis based on these 349 CpGs (330 genes) suggested the involvement of a number of genes responsible for immune and inflammatory system pathways, responses to stress and external stimuli, as well as wound healing and coagulation cascades. Interestingly, our observations include significant, replicable associations between SERPINA1 hypomethylation and COPD and lower average lung function phenotypes (combined P values: COPD, 1.5 × 10(-23); FEV(1)/FVC, 1.5 × 10(-35); FEV(1), 2.2 × 10(-40)).

CONCLUSIONS

Genetic and epigenetic pathways may both contribute to COPD. Many of the top associations between COPD and DNA methylation occur in biologically plausible pathways. This large-scale analysis suggests that DNA methylation may be a biomarker of COPD and may highlight new pathways of COPD pathogenesis.

The preclinical pharmacology of roflumilast--a selective, oral phosphodiesterase 4 inhibitor in development for chronic obstructive pulmonary disease

After more than two decades of research into phosphodiesterase 4 (PDE4) inhibitors, roflumilast (3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide) may become the first agent in this class to be approved for patient treatment worldwide. Within the PDE family of 11 known isoenzymes, roflumilast is selective for PDE4, showing balanced selectivity for subtypes A-D, and is of high subnanomolar potency. The active principle of roflumilast in man is its dichloropyridyl N-oxide metabolite, which has similar potency as a PDE4 inhibitor as the parent compound. The long half-life and high potency of this metabolite allows for once-daily, oral administration of a single, 500-microg tablet of roflumilast. The molecular mode of action of roflumilast--PDE4 inhibition and subsequent enhancement of cAMP levels--is well established. To further understand its functional mode of action in chronic obstructive pulmonary disease (COPD), for which roflumilast is being developed, a series of in vitro and in vivo preclinical studies has been performed. COPD is a progressive, devastating condition of the lung associated with an abnormal inflammatory response to noxious particles and gases, particularly tobacco smoke. In addition, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD), significant extrapulmonary effects, including comorbidities, may add to the severity of the disease in individual patients, and which may be addressed preferentially by orally administered remedies. COPD shows an increasing prevalence and mortality, and its treatment remains a high, unmet medical need. In vivo, roflumilast mitigates key COPD-related disease mechanisms such as tobacco smoke-induced lung inflammation, mucociliary malfunction, lung fibrotic and emphysematous remodelling, oxidative stress, pulmonary vascular remodelling and pulmonary hypertension. In vitro, roflumilast N-oxide has been demonstrated to affect the functions of many cell types, including neutrophils, monocytes/macrophages, CD4+ and CD8+ T-cells, endothelial cells, epithelial cells, smooth muscle cells and fibroblasts. These cellular effects are thought to be responsible for the beneficial effects of roflumilast on the disease mechanisms of COPD, which translate into reduced exacerbations and improved lung function. As a multicomponent disease, COPD requires a broad therapeutic approach that might be achieved by PDE4 inhibition. However, as a PDE4 inhibitor, roflumilast is not a direct bronchodilator. In summary, roflumilast may be the first-in-class PDE4 inhibitor for COPD therapy. In addition to being a non-steroid, anti-inflammatory drug designed to target pulmonary inflammation, the preclinical pharmacology described in this review points to a broad functional mode of action of roflumilast that putatively addresses additional COPD mechanisms. This enables roflumilast to offer effective, oral maintenance treatment for COPD, with an acceptable tolerability profile and the potential to favourably affect the extrapulmonary effects of the disease.

Fibrinogen binding to ICAM-1 promotes EGFR-dependent mucin production in human airway epithelial cells

Mucous hypersecretion is a serious feature of chronic airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Although mucins are produced via activation of an EGF receptor (EGFR) signaling cascade, the mechanisms leading to exaggerated mucin production in mucous hypersecretory diseases are unknown. Because expression of ICAM-1 and of the ICAM-1 ligand fibrinogen is increased in the airways of subjects with mucous hypersecretory diseases, we hypothesized that fibrinogen binding to ICAM-1 could increase EGFR-dependent mucin production in human airway (NCI-H292) epithelial cells. Consistent with this hypothesis, we found that an ICAM-1 neutralizing antibody and an ICAM-1(8-22) peptide that binds fibrinogen decreased mucin production induced by the EGFR ligand transforming growth factor (TGF)-alpha dose-dependently. Exogenous fibrinogen and a fibrinogen(117-133) peptide that binds ICAM-1 rescued mucin production in cells treated with the ICAM-1(8-22) peptide. Surprisingly, the ICAM-1(8-22) peptide increased EGFR phosphotyrosine and phospho-ERK1/2 in cells treated with TGF-alpha. The ICAM-1(8-22) peptide-induced increases in EGFR phosphotyrosine and phospho-ERK1/2 were prevented by exogenous fibrinogen, by the fibrinogen(117-133) peptide, and by selective inhibitors of phospholipase C (PLC), protein kinase C (PKC)-alpha/beta, and metalloproteases. These results suggest that fibrinogen binding to ICAM-1 promotes mucin production by decreasing TGF-alpha-induced EGFR and ERK1/2 activation and that the fibrinogen-ICAM-1-dependent decrease in EGFR and ERK1/2 activation occurs via inhibition of an early positive feedback pathway involving PLC- and PKC-alpha/beta-dependent metalloprotease activation and subsequent metalloprotease-dependent EGFR reactivation.

Serum interleukin-1beta as a marker for differentiation of asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are diseases of airway inflammation with clinical and physiological similarities, making their differentiation difficult. Airway inflammatory changes are associated with systemic changes. However, no serum marker is known for their differentiation. Therefore, serum interleukin (IL)-1beta levels were determined. Out of a total of 1023 patients screened, we included in the study ten patients each with atopic asthma, non-atopic asthma and COPD and ten healthy subjects. Skin prick tests with 14 inhalant allergens were performed on each patient. Blood was collected in the symptomatic and asymptomatic phases of the diseases and serum IL-1beta and IgE levels were determined. Our results showed that in the symptomatic phase in asthmatics, serum IL-1beta levels were higher (P<0.05) than in patients with COPD. Serum IgE levels were higher (P<0.05) in atopic asthmatics than in non-atopic asthmatics and in COPD patients. We conclude that serum IL-1beta level determination during the symptomatic phase of the diseases may help to differentiate asthmatics from patients with COPD. Serum IgE levels may differentiate atopic asthmatics from non-atopic asthmatics and COPD patients.

Adenovirus E1A regulates lung epithelial ICAM-1 expression by interacting with transcriptional regulators at its promoter

We focused on the regulation of inflammatory mediator expression by adenovirus E1A in lung epithelial cells and the role of this viral protein in the pathogenesis of chronic obstructive pulmonary disease (COPD). We previously reported that E1A, a well-known regulator of host genes, increased ICAM-1 expression in human bronchial epithelial (HBE) and A549 cells in response to LPS stimulation. In this report, we clarified the mechanism of this regulation. We found NF-kappaB translocation to the nucleus after LPS stimulation in both E1A-positive and -negative HBE cells. ICAM-1 promoter reporter constructs revealed that a mutation in the proximal NF-kappaB binding site completely inhibited increased transcription, whereas the mutation in a distal site did not. We analyzed the participation of E1A in transcriptional complex formation at this promoter using chromatin immunoprecipitation. In E1A-positive HBE and A549 cells, LPS stimulation increased ICAM-1 promoter immunoprecipitation by NF-kappaB p65 and p300 but not activator protein-1 antibodies with a concomitant increase by the E1A antibody. No increase was found in E1A-negative cells except in HBE cells with p65 antibody. The association of E1A with the increased promoter immunoprecipitation with p300 was also observed after TNF-alpha stimulation of A549 cells. These results suggest that adenovirus E1A regulates the ICAM-1 promoter through its proximal NF-kappaB binding site, most likely by interacting with the transcriptional complex that forms at this site. E1A regulation of the LPS response may play a role in acute exacerbations as a consequence of bacterial infections in COPD.

Cigarette smoke decreases MARCO expression in macrophages: implication in Mycoplasma pneumoniae infection

Bacterial infections including Mycoplasma pneumoniae (Mp) are a major cause of exacerbations in chronic obstructive pulmonary disease (COPD). Cigarette smoke (CS) is the leading cause of COPD, and affects the function of alveolar macrophages that act as the first line of defense against the invading respiratory pathogens. Macrophages express a transmembrane receptor called macrophage receptor with collagenous structure (MARCO) that is involved in the clearance of microorganisms. Whether CS down-regulates MARCO and eventually decreases the clearance of Mp has not been investigated. We utilized human monocytic cell line (THP-1)-derived macrophages to examine the effects of CS extract (CSE) on MARCO expression and Mp growth. Specifically, macrophages were pre-exposed to CSE for 6 h, and then infected with or without Mp for 2 h. MARCO was examined at both mRNA and protein levels by using real-time PCR and immunofluorescent staining, respectively. Mp in the supernatants was quantified by quantitative culture. In addition, a neutralizing MARCO antibody was added to macrophages to test if blockade of MARCO impaired Mp clearance. We found that CSE significantly decreased MARCO expression in a dose-dependant manner at 6 h post-CSE. Mp levels in CSE-treated cells were higher than those in non-CSE-treated cells, indicating a decreased pathogen clearance. Additionally, neutralizing MARCO in macrophages markedly increased Mp levels. Our results indicate that cigarette smoke exposure down-regulates MARCO expression in macrophages, which may be in part responsible for impaired bacterial (e.g., Mp) clearance.

Functional antagonism by GM-CSF on TNF-alpha-induced CD83 expression in human neutrophils

TNFalpha-induced expression of CD83 in leukocytes is mediated by NF-kappab. The aim of our present study was to investigate the underlying mechanism of a unique functional antagonism between GM-CSF and TNFalpha-induced up-regulation of CD83 in human neutrophils. CD83 was down-regulated by co-stimulation of neutrophils with TNFalpha and GM-CSF compared to TNFalpha alone both at the level of mRNA and protein. In marked contrast, the expression of IL-1RA was up-regulated under the same conditions. The down-regulation of CD83 was not mediated by modulation of the NF-kappab signaling pathway. Neither was it mediated by a decrease in mRNA stability of CD83. NF-kappab was modulated under these conditions as both the expression of the target gene IL-1RA as well as the phosphorylation of IkBalpha were up-regulated. Our results show that co-stimulation with pro-inflammatory cytokines such as TNFalpha and GM-CSF can have differential effects on inflammatory pathways initiated in the same target cell. GM-CSF can both synergize with TNFalpha in the case of expression of IL1-RA and antagonize in the case of CD83. Therefore, expression of CD83 as read out for activation of neutrophils in patients with inflammatory diseases is complicated by the presence of cross-modulating cytokines such as GM-CSF.

Proteomic analysis in lung tissue of smokers and COPD patients

RATIONALE

Although cigarette smoking is the most important risk factor for COPD, COPD develops in only a minority of smokers, suggesting a significant genetic role. To solve the underlying pathophysiologic mechanism, it is critical to understand genes and their final product, ie, proteins. We investigated the exclusive proteins from the lung tissues obtained from COPD patients using proteomics.

METHODS

Nontumorous lung tissue specimens were obtained from patients who underwent surgery for lung cancer. We included 22 subjects: nonsmokers (n = 8), smokers without COPD (healthy smokers, n = 7), and smokers with COPD (n = 7). Proteins were separated from their spots with two-dimensional polyacrylamide gel electrophoresis and examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). To validate the proteins from the above procedures, Western blotting and immunohistochemistry were conducted.

RESULTS

Twelve protein spots from COPD group significantly increased or decreased compared with the other two groups were chosen for MALDI-TOF-MS analysis. Eight proteins were up-regulated in the COPD group as compared with the nonsmokers. Meanwhile, five proteins from the COPD group were up-regulated and five were down-regulated when compared with healthy smokers. Of these, matrix metalloproteinase (MMP)-13 and thioredoxin-like 2 were significantly increased in the COPD patients by Western blot and immunohistochemistry. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes; however, thioredoxin-like 2 was primarily seen in the bronchial epithelium.

CONCLUSIONS

MMP-13 and thioredoxin-like 2 in lungs increased in patients with COPD. MMP-13 was mainly expressed in the alveolar macrophages and type II pneumocytes. In contrast, thioredoxin-like 2 was primarily seen in the bronchial epithelium.