Inhaled steroids modulate extracellular matrix composition in bronchial biopsies of COPD patients: a randomized, controlled trial

RATIONALE

Smoking and inflammation contribute to the pathogenesis of chronic obstructive pulmonary disease (COPD), which involves changes in extracellular matrix. This is thought to contribute to airway remodeling and airflow obstruction. We have previously observed that long-term treatment with inhaled corticosteroids can not only reduce bronchial inflammation, but can also attenuate lung function decline in moderate-severe COPD. We hypothesized that inhaled corticosteroids and current smoking modulate bronchial extracellular matrix components in COPD.

OBJECTIVE

To compare major extracellular matrix components (elastic fibers; proteoglycans [versican, decorin]; collagens type I and III) in bronchial biopsies 1) after 30-months inhaled steroids treatment or placebo; and 2) between current and ex-smokers with COPD.

METHODS

We included 64 moderate-severe, steroid-naive COPD patients (24/40 (ex)-smokers, 62±7 years, 46 (31-54) packyears, post-bronchodilator forced expiratory volume in one second (FEV1) 62±9% predicted) at baseline in this randomized, controlled trial. 19 and 13 patients received 30-months treatment with fluticasone or placebo, respectively. Bronchial biopsies collected at baseline and after 30 months were studied using (immuno)histochemistry to evaluate extracellular matrix content. Percentage and density of stained area were calculated by digital image analysis.

RESULTS

30-Months inhaled steroids increased the percentage stained area of versican (9.6% [CI 0.9 to 18.3%]; p = 0.03) and collagen III (20.6% [CI 3.8 to 37.4%]; p = 0.02) compared to placebo. Increased collagen I staining density correlated with increased post-bronchodilator FEV1 after inhaled steroids treatment (Rs = 0.45, p = 0.04). There were no differences between smokers and ex-smokers with COPD in percentages and densities for all extracellular matrix proteins.

CONCLUSIONS

These data show that long-term inhaled corticosteroids treatment partially changes the composition of extracellular matrix in moderate-severe COPD. This is associated with increased lung function, suggesting that long-term inhaled steroids modulate airway remodeling thereby potentially preventing airway collapse in COPD. Smoking status is not associated with bronchial extracellular matrix proteins.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00158847.

Nonantibiotic macrolides prevent human neutrophil elastase-induced mucus stasis and airway surface liquid volume depletion

Mucus clearance is an important component of the lung's innate defense system. A failure of this system brought on by mucus dehydration is common to both cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Mucus clearance rates are regulated by the volume of airway surface liquid (ASL) and by ciliary beat frequency (CBF). Chronic treatment with macrolide antibiotics is known to be beneficial to both CF and COPD patients. However, chronic macrolide usage may induce bacterial resistance. We have developed a novel macrolide, 2'-desoxy-9-(S)-erythromycylamine (GS-459755), that has significantly diminished antibiotic activity against Staphylococcus aureus, Streptococcus pneumonia, Moraxella catarrhalis, and Haemophilus influenzae. Since neutrophilia frequently occurs in chronic lung disease and human neutrophil elastase (HNE) induces mucus stasis by activating the epithelial sodium channel (ENaC), we tested the ability of GS-459755 to protect against HNE-induced mucus stasis. GS-459755 had no effect on HNE activity. However, GS-459755 pretreatment protected against HNE-induced ASL volume depletion in human bronchial epithelial cells (HBECs). The effect of GS-459755 on ASL volume was dose dependent (IC₅₀ ~3.9 μM) and comparable to the antibacterial macrolide azithromycin (IC₅₀ ~2.4 μM). Macrolides had no significant effect on CBF or on transepithelial water permeability. However, the amiloride-sensitive transepithelial voltage, a marker of ENaC activity, was diminished by macrolide pretreatment. We conclude that GS-459755 may limit HNE-induced activation of ENaC and may be useful for the treatment of mucus dehydration in CF and COPD without inducing bacterial resistance.

Anti-interleukin-33 inhibits cigarette smoke-induced lung inflammation in mice

The mechanism by which cigarette smoke (CS) causes chronic obstructive pulmonary disease (COPD) is poorly understood. Interleukin-33 (IL-33) is a pleiotropic cytokine predominantly expressed in lung tissue and can elicit airway inflammation in naive mice. We tested the hypothesis that IL-33 is induced by CS and contributes to CS-mediated airway inflammation in a mouse model of CS-induced COPD. Groups of mice were exposed to CS three times per day for 4 consecutive days. The expression levels of IL-33 and ST2 were markedly enhanced in the lung tissue of mice inhaling CS. Exposure to CS also induced neutrophil and macrophage infiltration and expression of inflammatory cytokines (IL-1β, tumour necrosis factor-α, IL-17), chemokines (monocyte chemoattractant protein-1) and mucin 5, subtypes A and C in the airways. More importantly, all of these CS-induced pathogenic changes were significantly inhibited by treatment with neutralizing anti-IL-33 antibody delivered intranasally. Hence, our results suggest that IL-33 plays a critical role in CS-mediated airway inflammation and may be a therapeutic target in CS-related diseases, including COPD.

Role of transcription factors in the pathogenesis of asthma and COPD

Inflammation is a central feature of asthma and chronic obstructive pulmonary disease (COPD). Despite recent advances in the knowledge of the pathogenesis of asthma and COPD, much more research on the molecular mechanisms of asthma and COPD are needed to aid the logical development of new therapies for these common and important diseases, particularly in COPD where no effective treatments currently exist. In the future the role of the activation/repression of different transcription factors and the genetic regulation of their expression in asthma and COPD may be an increasingly important aspect of research, as this may be one of the critical mechanisms regulating the expression of different clinical phenotypes and their responsiveness to therapy, particularly to anti-inflammatory drugs.

Exchange protein directly activated by cAMP (epac): a multidomain cAMP mediator in the regulation of diverse biological functions

Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and gene transcription, is reflected by the award of five Nobel prizes. The discovery of Epac (exchange protein directly activated by cAMP) has ignited a new surge of cAMP-related research and has depicted novel cAMP properties independent of protein kinase A and cyclic nucleotide-gated channels. The multidomain architecture of Epac determines its activity state and allows cell-type specific protein-protein and protein-lipid interactions that control fine-tuning of pivotal biologic responses through the "old" second messenger cAMP. Compartmentalization of cAMP in space and time, maintained by A-kinase anchoring proteins, phosphodiesterases, and β-arrestins, contributes to the Epac signalosome of small GTPases, phospholipases, mitogen- and lipid-activated kinases, and transcription factors. These novel cAMP sensors seem to implement certain unexpected signaling properties of cAMP and thereby to permit delicate adaptations of biologic responses. Agonists and antagonists selective for Epac are developed and will support further studies on the biologic net outcome of the activation of Epac. This will increase our current knowledge on the pathophysiology of devastating diseases, such as diabetes, cognitive impairment, renal and heart failure, (pulmonary) hypertension, asthma, and chronic obstructive pulmonary disease. Further insights into the cAMP dynamics executed by the Epac signalosome will help to optimize the pharmacological treatment of these diseases.

Macrophage heterogeneity in respiratory diseases

Macrophages are among the most abundant cells in the respiratory tract, and they can have strikingly different phenotypes within this environment. Our knowledge of the different phenotypes and their functions in the lung is sketchy at best, but they appear to be linked to the protection of gas exchange against microbial threats and excessive tissue responses. Phenotypical changes of macrophages within the lung are found in many respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. This paper will give an overview of what macrophage phenotypes have been described, what their known functions are, what is known about their presence in the different obstructive and restrictive respiratory diseases (asthma, COPD, pulmonary fibrosis), and how they are thought to contribute to the etiology and resolution of these diseases.

Detection of lung dysfunction using ventilation and perfusion SPECT in a mouse model of chronic cigarette smoke exposure

Chronic obstructive pulmonary disease is a leading cause of morbidity and mortality worldwide. Exposure to cigarette smoke (CS) is a major risk factor for developing this chronic airflow impairment, but the early progression of disease is not well defined or understood. Ventilation/perfusion (V/Q) SPECT provides a noninvasive assessment of lung function to further our current understanding of how CS affects the lung.

METHODS

BALB/c mice were imaged with V/Q SPECT and CT after 8 and 24 wk of whole-body exposure to mainstream CS. Bronchoalveolar lavage was collected and cell differentials produced to determine inflammatory patterns. Histologic lung sections were collected, and a semiautomated quantitative analysis of airspace enlargement was applied to whole histology slices.

RESULTS

Exposure to CS induced an inflammatory response that included increases in the numbers of both mononuclear cells and neutrophils. Airspace enlargement was also significantly increased at 8 wk of CS exposure and was still more pronounced at 24 wk. Ventilation and perfusion correlation at the voxel level depicted a significant decrease in matching at 8 wk of CS exposure that was also apparent after 24 wk. The standard deviation (SD) of the log(V/Q) curve, a basic measure of heterogeneity, was increased from 0.44 ± 0.02 in age-matched controls to 0.62 ± 0.05 with CS exposure at 24 wk, indicating an increase in V/Q mismatching between 8 and 24 wk of CS exposure. CT, however, was not capable of discriminating control from CS-exposed animals at either time point, even with greater resolution and respiratory gating.

CONCLUSION

This study demonstrated that, before CT detection of structural changes, V/Q imaging detected changes in gas-exchange potential. This functional impairment corresponded to increased lung inflammation and increased airspace enlargement. In vivo V/Q imaging can detect early changes to the lung caused by CS exposure and thus provides a noninvasive method of longitudinally studying lung dysfunction in preclinical models. In the future, these measures could be applied clinically to study and diagnose the early stages of chronic obstructive pulmonary disease.

Exercise and COPD: therapeutic responses, disease-related outcomes, and activity-promotion strategies

Chronic obstructive pulmonary disease (COPD) reduces patients' exercise capacities and their abilities to perform daily physical activities, thereby increasing morbidity and mortality rates. The cycle of dyspnea, deconditioning, and declining physical activity not only accelerates the progression of COPD but also increases the risk for developing or aggravating metabolic and cardiovascular diseases. Cardiovascular and metabolic comorbidities also limit physical function, and their disabling effects in combination with COPD may be greater than the effects of each disease alone. The impact of COPD and its treatment on the ability to exercise, and the degree of physical activity in daily life, can be measured by field-based tests (eg, the 6-minute walk test or incremental and endurance shuttle-walk test), laboratory-based tests (eg, incremental or constant work-rate treadmill and cycle-ergometer tests), and physical activity assessments (eg, questionnaires and accelerometers). Walking tests increase oxygen consumption and desaturation in patients with COPD more than cycling tests with similar work-rate profiles and may more closely resemble patients' normal activities. Despite the questionable relevance of exercise testing to patients' daily functionality, exercise parameters remain important predictors of survival in patients with COPD. Treatment of COPD (pharmacotherapy, pulmonary rehabilitation, or both) can increase exercise capacity and physical activity in daily life, which potentially slows the decline of lung function, reduces the frequencies of exacerbations and hospitalizations, decreases mortality, slows the progression of comorbidities, improves health-related quality of life, and increases the activity reserve for routine function. This article examines the interactions of reduced physical activity and decreased exercise capacity with the progression of COPD, comorbidities, and mortality. The article also describes the available exercise tests for patients with COPD and reviews the evidence indicating that treating COPD improves exercise capacity. Notably, it appears that even mild COPD reduces exercise capacity and daily physical activity, indicating the need for early intervention.

Enhanced expression of human β-defensin 2 in peripheral lungs of patients with chronic obstructive pulmonary disease

Human β-defensin 2 (hBD-2) has antimicrobial activity and may play a role in airway mucosal defense, but studies have not yet examined its expression in lung tissue of patients with chronic obstructive pulmonary disease (COPD). Here we investigated hBD-2 levels in lung tissues of COPD patients and analyzed their correlations with IL-8, IL-1β, cigarette smoking and lung function in order to see whether the protein may be involved in pathogenesis of the disease. Peripheral lung tissue specimens were obtained from 51 patients who underwent lung resection for peripheral lung cancer: healthy non-smokers (n=8), healthy current smokers (n=7), non-smokers with COPD (n=11), and current smokers with COPD (n=25). RT-PCR and immunohistochemical staining were used to detect expression levels of hBD-2, IL-8 and IL-1β. Expression of hBD-2 mRNA was significantly higher in COPD patients than in healthy controls, and significantly higher in current smokers than in non-smokers (p<0.05). Among healthy controls, hBD-2 mRNA levels were similar between current smokers and non-smokers. Immunohistochemistry showed hBD-2 protein to be expressed mainly in epithelia of distal bronchioles and its expression pattern among our patient groups mirrored that of the mRNA. IL-8 mRNA levels were significantly higher in COPD patients than in healthy controls (p<0.05), while IL-1β mRNA levels did not differ significantly among the groups. Levels of hBD-2 mRNA positively correlated with levels of IL-8 mRNA (r=0.545, p=0.002), and negatively correlated with FEV1/FVC ratios and with predicted FEV1% values (r=-0.406, p=0.011). Our results indicate that hBD-2 expression is elevated in distal airways of COPD patients and that it may be involved in pathogenesis of the disease. Our data implicate cigarette smoking as a factor that may elevate hBD-2 levels in lung tissues of COPD patients.

Inflammation in COPD: implications for management

Chronic obstructive pulmonary disease (COPD) is recognized by the Global Initiative for Chronic Obstructive Lung Disease guidelines as an inflammatory disease state, and treatment rationales are provided accordingly. However, not all physicians follow or are even aware of these guidelines. Research has shown that COPD inflammation involves multiple inflammatory cells and mediators and the underlying pathology differs from asthma inflammation. For these reasons, therapeutic agents that are effective in asthma patients may not be optimal in COPD patients. COPD exacerbations are intensified inflammatory events compared with stable COPD. The clinical and systemic consequences believed to result from the chronic inflammation observed in COPD suggest that inflammation intensity is a key factor in COPD and exacerbation severity and frequency. Although inhaled corticosteroids are commonly used and are essential in asthma management, their efficacy in COPD is limited, with only a modest effect at reducing exacerbations. The importance of inflammation in COPD needs to be better understood by clinicians, and the differences in inflammation in COPD versus asthma should be considered carefully to optimize the use of anti-inflammatory agents.

Pro-inflammatory phenotype of COPD fibroblasts not compatible with repair in COPD lung

Chronic obstructive pulmonary disease (COPD) is characterized by loss of elastic fibres from small airways and alveolar walls, with the decrease in elastin increasing with disease severity. It is unclear why there is a lack of repair of elastic fibres. We have examined fibroblasts cultured from lung tissue from subjects with or without COPD to determine if the secretory profile explains lack of tissue repair. In this study, fibroblasts were cultured from lung parenchyma of patients with mild COPD [Global initiative for chronic Obstructive Lung Disease (GOLD) 1, n= 5], moderate to severe COPD (GOLD 2–3, n= 12) and controls (non-COPD, n= 5). Measurements were made of proliferation, senescence-associated β-galactosidase-1, mRNA expression of IL-6, IL-8, MMP-1, tropoelastin and versican, and protein levels for IL-6, IL-8, PGE_2, tropoelastin, insoluble elastin, and versican. GOLD 2–3 fibroblasts proliferated more slowly (P < 0.01), had higher levels of senescence-associated β-galactosidase-1 (P < 0.001) than controls and showed significant increases in mRNA and/or protein for IL-6 (P < 0.05), IL-8 (P < 0.01), MMP-1 (P < 0.05), PGE₂ (P < 0.05), versican (P < 0.05) and tropoelastin (P < 0.05). mRNA expression and/or protein levels of tropoelastin (P < 0.01), versican (P < 0.05), IL-6 (P < 0.05) and IL-8 (P < 0.05) were negatively correlated with FEV1% of predicted. Insoluble elastin was not increased. In summary, fibroblasts from moderate to severe COPD subjects display a secretory phenotype with up-regulation of inflammatory molecules including the matrix proteoglycan versican, and increased soluble, but not insoluble, elastin. Versican inhibits assembly of tropoelastin into insoluble elastin and we conclude that the pro-inflammatory phenotype of COPD fibroblasts is not compatible with repair of elastic fibres.

Nicotine-induced epithelial-mesenchymal transition via Wnt/β-catenin signaling in human airway epithelial cells

Epithelial-mesenchymal transition (EMT) has been proposed to be a mechanism in airway remodeling, which is a characteristic of chronic obstructive pulmonary disease (COPD). Studies have shown that cigarette smoke and nicotine are factors that induce Wnt/β-catenin activation, which is a pathway that has also been implicated in EMT. The main aim of this study was to test whether human bronchial epithelial cells are able to undergo EMT in vitro following nicotine stimulation via the Wnt3a/β-catenin signaling pathway. We show that nicotine activates the Wnt3a signal pathway, which leads to the translocation of β-catenin into the nucleus and activation of β-catenin/Tcf-dependent transcription in the human bronchial epithelial cell (HBEC) line. This accumulation was accompanied by an increase in smooth muscle actin, vimentin, matrix metalloproteinases-9, and type I collagen expression as well as downregulation of E-cadherin, which are typical characteristics of EMT. We also noted that the release of TGF-β(1) from these cells was stimulated by nicotine. Knockdown of Wnt3a with small interfering RNA (siRNA) prevented these effects, implying that β-catenin activation in these responses is Wnt3a dependent. Furthermore, specific knockdown of TGF-β(1) with TGF-β(1) siRNA partially prevented nicotine-induced EMT, suggesting that TGF-β(1) has a role in nicotine-mediated EMT in HBECs. These results suggest that HBECs are able to undergo EMT in vitro upon nicotine stimulation via the Wnt3a/β-catenin signaling pathway.

Multiple facets of cAMP signalling and physiological impact: cAMP compartmentalization in the lung

Therapies involving elevation of the endogenous suppressor cyclic AMP (cAMP) are currently used in the treatment of several chronic inflammatory disorders, including chronic obstructive pulmonary disease (COPD). Characteristics of COPD are airway obstruction, airway inflammation and airway remodelling, processes encompassed by increased airway smooth muscle mass, epithelial changes, goblet cell and submucosal gland hyperplasia. In addition to inflammatory cells, airway smooth muscle cells and (myo)fibroblasts, epithelial cells underpin a variety of key responses in the airways such as inflammatory cytokine release, airway remodelling, mucus hypersecretion and airway barrier function. Cigarette smoke, being next to environmental pollution the main cause of COPD, is believed to cause epithelial hyperpermeability by disrupting the barrier function. Here we will focus on the most recent progress on compartmentalized signalling by cAMP. In addition to G protein-coupled receptors, adenylyl cyclases, cAMP-specific phospho-diesterases (PDEs) maintain compartmentalized cAMP signalling. Intriguingly, spatially discrete cAMP-sensing signalling complexes seem also to involve distinct members of the A-kinase anchoring (AKAP) superfamily and IQ motif containing GTPase activating protein (IQGAPs). In this review, we will highlight the interaction between cAMP and the epithelial barrier to retain proper lung function and to alleviate COPD symptoms and focus on the possible molecular mechanisms involved in this process. Future studies should include the development of cAMP-sensing multiprotein complex specific disruptors and/or stabilizers to orchestrate cellular functions. Compartmentalized cAMP signalling regulates important cellular processes in the lung and may serve as a therapeutic target.

Increase of 27-hydroxycholesterol in the airways of patients with COPD: possible role of 27-hydroxycholesterol in tissue fibrosis

BACKGROUND

27-Hydroxycholesterol (27-OHC) is produced from cholesterol by sterol 27-hydroxylase as an intermediate in the biosynthesis pathway of bile acid. Recently, 27-OHC was reported to cause inflammation and apoptosis in various types of cells. The aim of this study was to assess the production of 27-OHC in the airways of patients with COPD and to elucidate the possible role of 27-OHC in the tissue fibrosis of COPD.

METHODS

Lung tissues were obtained from six control subjects and six patients with COPD, and sputum samples were obtained from 11 healthy subjects and 15 patients with COPD. The expression of sterol 27-hydroxylase in the lung was investigated by immunohistochemistry. The amounts of 27-OHC in the sputum were quantified by the liquid chromatography-tandem mass spectrometry method. Because peribronchial fibrosis in peripheral airways is involved in the airflow limitation of COPD, we investigated the profibrotic effects of 27-OHC in vitro.

RESULTS

The expression of sterol 27-hydroxylase was significantly enhanced in the lung tissues of patients with COPD compared with control subjects. The amounts of 27-OHC in the sputum were significantly increased in the patients with COPD (P < .01), and the degree of 27-OHC production was negatively correlated with lung function (P < .01). 27-OHC augmented the differentiation of lung fibroblasts into myofibroblasts and the production of extracellular matrix protein through activation of nuclear factor-κB and subsequent transforming growth factor-β(1) upregulation.

CONCLUSIONS

27-OHC production is enhanced in the airways of patients with COPD and might be involved in the pathogenesis of COPD.

Acute cigarette smoke exposure impairs proteasome function in the lung

Cigarette smoke mediates DNA damage, lipid peroxidation, and modification and misfolding of proteins, thereby inducing severe cellular damage. The ubiquitin proteasome system serves as the major disposal system for modified and misfolded proteins and is thus essential for proper cellular function. Its role in cigarette smoke-induced cell damage, however, is largely unknown. We hypothesized that the ubiquitin-proteasome system is involved in the degradation of cigarette smoke-damaged proteins and that cigarette smoke exposure impairs the proteasome itself. Here, we show that treatment of human alveolar epithelial cells with cigarette smoke extract (CSE) induced time- and dose-dependent cell death, a rise in intracellular reactive oxygen species, and increased levels of carbonylated and polyubiquitinated proteins. While high doses of CSE severely impaired all three proteasomal activities, low CSE concentrations significantly inhibited only the trypsin-like activity of the proteasome in alveolar and bronchial epithelial cells. Moreover, acute exposure of mice to cigarette smoke significantly impaired the trypsin-like activity by 25% in the lungs. Reduced proteasome activity was not due to transcriptional regulation of the proteasome. Notably, cigarette smoke exposure induced accumulation of polyubiquitinated proteins in the soluble and insoluble protein fraction of the lung. We show for the first time that acute exposure to cigarette smoke directly impairs proteasome activity in the lungs of mice and in human epithelial cells at low doses without affecting proteasome expression. Our results indicate that defective proteasomal protein quality control may exacerbate the detrimental effects of cigarette smoke in the lung.

Distinct PKA and Epac compartmentalization in airway function and plasticity

Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases characterized by airway obstruction, airway inflammation and airway remodelling. Next to inflammatory cells and airway epithelial cells, airway mesenchymal cells, including airway smooth muscle cells and (myo)fibroblasts, substantially contribute to disease features by the release of inflammatory mediators, smooth muscle contraction, extracellular matrix deposition and structural changes in the airways. Current pharmacological treatment of both diseases intends to target the dynamic features of the endogenous intracellular suppressor cyclic AMP (cAMP). This review will summarize our current knowledge on cAMP and will emphasize on key discoveries and paradigm shifts reflecting the complex spatio-temporal nature of compartmentalized cAMP signalling networks in health and disease. As airway fibroblasts and airway smooth muscle cells are recognized as central players in the development and progression of asthma and COPD, we will focus on the role of cAMP signalling in their function in relation to airway function and plasticity. We will recapture on the recent identification of cAMP-sensing multi-protein complexes maintained by cAMP effectors, including A-kinase anchoring proteins (AKAPs), proteins kinase A (PKA), exchange protein directly activated by cAMP (Epac), cAMP-elevating seven-transmembrane (7TM) receptors and phosphodiesterases (PDEs) and we will report on findings indicating that the pertubation of compartmentalized cAMP signalling correlates with the pathopysiology of obstructive lung diseases. Future challenges include studies on cAMP dynamics and compartmentalization in the lung and the development of novel drugs targeting these systems for therapeutic interventions in chronic obstructive inflammatory diseases.

Reproducibility and respiratory function correlates of exhaled breath fingerprint in chronic obstructive pulmonary disease

BACKGROUND

The electronic nose (e nose) provides distinctive breath fingerprints for selected respiratory diseases. Both reproducibility and respiratory function correlates of breath fingerprint are poorly known.

OBJECTIVES

To measure reproducibility of breath fingerprints and to assess their correlates among respiratory function indexes in elderly healthy and COPD subjects.

METHOD

25 subjects (5 COPD patients for each GOLD stage and 5 healthy controls) over 65 years underwent e-nose study through a seven sensor system and respiratory function tests at times 0, 7, and 15 days. Reproducibility of the e nose pattern was computed. The correlation between volatile organic compound (VOC) pattern and respiratory function/clinical parameters was assessed by the Spearman's rho.

MEASUREMENTS AND MAIN RESULTS

VOC patterns were highly reproducible within healthy and GOLD 4 COPD subjects, less among GOLD 1-3 patients.VOC patterns significantly correlated with expiratory flows (Spearman's rho ranging from 0.36 for MEF25% and sensor Co-Buti-TPP, to 0.81 for FEV1% and sensor Cu-Buti-TPP p<0.001)), but not with residual volume and total lung capacity.

CONCLUSIONS

VOC patterns strictly correlated with expiratory flows. Thus, e nose might conveniently be used to assess COPD severity and, likely, to study phenotypic variability. However, the suboptimal reproducibility within GOLD 1-3 patients should stimulate further research to identify more reproducible breath print patterns.

Hyaluronan and layilin mediate loss of airway epithelial barrier function induced by cigarette smoke by decreasing E-cadherin

Cigarette smoke (CigS) exposure is associated with increased bronchial epithelial permeability and impaired barrier function. Primary cultures of normal human bronchial epithelial cells exposed to CigS exhibit decreased E-cadherin expression and reduced transepithelial electrical resistance. These effects were mediated by hyaluronan (HA) because inhibition of its synthesis with 4-methylumbelliferone prevented these effects, and exposure to HA fragments of <70 kDa mimicked these effects. We show that the HA receptor layilin is expressed apically in human airway epithelium and that cells infected with lentivirus expressing layilin siRNAs were protected against increased permeability triggered by both CigS and HA. We identified RhoA/Rho-associated protein kinase (ROCK) as the signaling effectors downstream layilin. We conclude that HA fragments generated by CigS bind to layilin and signal through Rho/ROCK to inhibit the E-cadherin gene and protein expression, leading to a loss of epithelial cell-cell contact. These studies suggest that HA functions as a master switch protecting or disrupting the epithelial barrier in its high versus low molecular weight form and that its depolymerization is a first and necessary step triggering the inflammatory response to CigS.

Strategies to decrease ongoing oxidant burden in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality and morbidity globally, and its development is mainly associated with tobacco/biomass smoke-induced oxidative stress. Hence, targeting systemic and local oxidative stress with agents that can balance the antioxidant/redox system can be expected to be useful in the treatment of COPD. Preclinical and clinical trials have revealed that antioxidants/redox modulators can detoxify free radicals and oxidants, control expression of redox and glutathione biosynthesis genes, chromatin remodeling and inflammatory gene expression; and are especially useful in preventing COPD exacerbations. In this review, various novel approaches and problems associated with these approaches in COPD are reviewed.

Imbalance of Th17/Treg cells in mice with chronic cigarette smoke exposure

BACKGROUND

Recent studies have revealed that autoimmune responses mediated by CD4(+) T cells may contribute to the development of chronic obstructive pulmonary disease (COPD). Meanwhile, imbalance of Th17/Treg has been reported to play a key role in the pathogenesis of autoimmune diseases. However, information on Th17/Treg balance in COPD is relatively limited.

METHOD

We established a mouse model of COPD induced by chronic cigarette smoke (CS) exposure. Th17 and Treg in lung tissue and peripheral blood were quantified by flow cytometry. The level of the specific transcription factors of both T cell subsets in lung tissue was determined by real-time PCR. The expressions of Th17- and Treg-related cytokines in serum and bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found that mice with chronic CS exposure showed significant increase in lung Th17 prevalence, retinoic acid orphan receptor (ROR)-γt mRNA and Th17-related cytokines (IL-17A, IL-6 and IL-23). Meanwhile, there was obvious decrease in Treg cell prevalence, Forkhead box (Fox) p3 mRNA and Treg-related cytokine IL-10, as compared to mice underwent sub-acute CS exposure and air-exposure. Similar tendency was also found for the Th17/Treg ratio in peripheral blood.

CONCLUSIONS

Our study thus reveals that the Th17/Treg imbalance exists in mice with chronic CS exposure, suggesting its potential role in the breakdown of immune self-tolerance in COPD. Further research on regulation of Th17/Treg balance may provide insights into the development of new therapeutic targets for this disease.

Antibiotic therapy in elderly patients with acute exacerbation of chronic bronchitis

Chronic bronchitis (CB) is a critical component of chronic obstructive pulmonary disease (COPD). Emphysema, reversible airway disease and bronchiectasis also contribute to COPD. Elderly patients are at increased risk for COPD and its components - emphysema, CB and bronchiectasis. In addition, older patients are at increased risk for resistant organisms during episodes of acute exacerbation of CB (AECB). These organisms include the more common bacteria implicated in AECB, such as Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae, and less common nonenteric, Gram-negative organisms such as Pseudomonas aeruginosa. Risk-stratified antibiotic treatment guidelines for AECB appear to be useful, although they have not been prospectively validated for the general CB population, and especially not in the elderly CB population. Many of the AECB treatment guidelines that are stratified based on risk factors have recommended that the oral respiratory fluoroquinolone antibiotics (gemifloxacin, levofloxacin and moxifloxacin) play a second-line but pivotal role, particularly in patients who have failed initial antibiotic treatment for simple CB or as initial treatment for complicated CB.

Geroprotectors as a novel therapeutic strategy for COPD, an accelerating aging disease

Chronic obstructive pulmonary disease (COPD) progresses very slowly and the majority of patients are therefore elderly. COPD is characterized by an abnormal persistent inflammatory response to noxious environmental stimuli and there are increasing evidences for a close relationship between premature aging and chronic inflammatory diseases. Thus, COPD is considered to be a disease of an accelerating aging. In this review, we collected the evidence for roles of aging on pathogenesis of COPD and considered future therapeutic strategy for COPD based on this senescence hypothesis. Since calorie restriction has been proved to extend lifespan, many efforts were made to clarify the molecular mechanism of aging. Aging is defined as the progressive decline of homeostasis that occurs after the reproductive phase of life is complete, leading to an increasing risk of disease or death due to impaired DNA repair after damage by oxidative stress or telomere shortening as a result of repeated cell division. During aging, pulmonary function progressively deteriorates; innate immunity is impaired and pulmonary inflammation increases, accompanied by structural changes, such as an enlargement of airspaces. Noxious environmental gases, such as cigarette smoke, may worsen these aging-related events in the lung or accelerate aging of the lung due to reduction in anti-aging molecules and/or stimulation of aging molecules. Aging signaling are complex but conserved in divert species, such as worm, fruit fry, rodent and humans. Especially the insulin like growth factor (IGF-1) signaling was well documented. Geroprotectors are therapeutics that affect the root cause of aging and age-related diseases, and thus prolong the life-span of animals. Most of geroprotectors such as melatonin, metformin, rapamycin and resveratrol are anti-oxidant or anti-aging molecule regulators. Therefore, geroprotection for the lung might be an attractive approach for the treatment of COPD by preventing premature aging of lung.

Secondhand smoke exposure causes bronchial hyperreactivity via transcriptionally upregulated endothelin and 5-hydroxytryptamine 2A receptors

BACKGROUND

Cigarette smoke exposure is strongly associated with airway hyperreactivity (AHR) which is the main characteristic seen in asthma. The intracellular MAPK signaling pathways are suggested to be associated with the airway damage to the AHR. In the present study, we hypothesize that secondhand cigarette smoke (SHS) exposure upregulates the bronchial contractile receptors via activation of the Raf/ERK/MAPK pathway.

METHODOLOGY/PRINCIPAL FINDINGS

Rats were exposed to SHS for 3 h daily for up to 8 weeks. The receptor agonists-induced bronchial contractile reactivity was analyzed with a sensitive myograph system. The mRNA transcription and protein translation of the target receptors and the kinases in Raf/ERK/MAPK pathway were investigated by real-time PCR, Western blotting and immunofluorescence, respectively. Compared with exposure to fresh air, SHS induced enhanced bronchial contractile responses mediated by the 5-hydroxytryptamine 2A (5-HT(2A)) receptors as well as the endothelin type B (ET(B)) and type A (ET(A)) receptors. The response curves were shifted toward the left with an increased maximal contraction (E(max)) demonstrating that SHS induced AHR. Additionally, the mRNA and protein levels of the 5-HT(2A), ET(B) and ET(A) receptors were increased. Furthermore, SHS exposure increased the phosphorylation of Raf-1 and ERK1/2, but it did not alter p38 or JNK. A Raf-1 inhibitor (GW5074) suppressed the SHS-induced increase in the expression of 5-HT(2A) and ET(A) receptors and the receptor-mediated AHR.

CONCLUSIONS/SIGNIFICANCE

Our findings show that SHS exposure induces transcriptional upregulation of the 5-HT(2A), ET(B) and ET(A) receptors in rat bronchial smooth muscle cells, which mediates AHR. The Raf/ERK/MAPK pathway is involved in SHS-associated receptor upregulation and AHR.

CFTR regulates early pathogenesis of chronic obstructive lung disease in βENaC-overexpressing mice

Background

Factors determining the onset and severity of chronic obstructive pulmonary disease remain poorly understood. Previous studies demonstrated that airway surface dehydration in βENaC-overexpressing (βENaC-Tg) mice on a mixed genetic background caused either neonatal mortality or chronic obstructive lung disease suggesting that the onset of lung disease was modulated by the genetic background.

Methods

To test this hypothesis, we backcrossed βENaC-Tg mice onto two inbred strains (C57BL/6 and BALB/c) and studied effects of the genetic background on neonatal mortality, airway ion transport and airway morphology. Further, we crossed βENaC-Tg mice with CFTR-deficient mice to validate the role of CFTR in early lung disease.

Results

We demonstrate that the C57BL/6 background conferred increased CFTR-mediated Cl⁻ secretion, which was associated with decreased mucus plugging and mortality in neonatal βENaC-Tg C57BL/6 compared to βENaC-Tg BALB/c mice. Conversely, genetic deletion of CFTR increased early mucus obstruction and mortality in βENaC-Tg mice.

Conclusions

We conclude that a decrease or absence of CFTR function in airway epithelia aggravates the severity of early airway mucus obstruction and related mortality in βENaC-Tg mice. These results suggest that genetic or environmental factors that reduce CFTR activity may contribute to the onset and severity of chronic obstructive pulmonary disease and that CFTR may serve as a novel therapeutic target.

Oxidized phospholipids impair pulmonary antibacterial defenses: evidence in mice exposed to cigarette smoke

Patients with COPD are associated with poor pulmonary anti-bacterial innate defenses, which increase the risk for frequent acute exacerbations caused by bacterial infection. Despite elevated numbers of phagocytes (macrophages and neutrophils), airways of patients with COPD show stable bacterial colonization. A defect in the phagocytic ability of alveolar macrophages (AMs) is one of the primary reasons for failure to clear the invading bacteria in airways of smokers and COPD patients and also in mice exposed to cigarette smoke (CS). Oxidative stress, as a result of CS exposure is implicated; however, the factors or mediators that inhibit phagocytic activity of AMs in lungs of smokers remain unclear. In the current study, we provide evidence that accumulation of oxidized phospholipids (Ox-PLs) mediate inhibition of phagocytic function of AMs in CS-exposed mice. Mice exposed to 6months of CS showed impaired bacterial phagocytosis and clearance by AMs and elevated levels of Ox-PLs in bronchoalveolar lavage fluid (BALF), compared to mice exposed to room air. Intratracheal instillation of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OX-PAPC) inhibited phagocytic activity of AMs and impaired pulmonary bacterial clearance in mice. In vitro studies demonstrated that exposure of J774 macrophages to OX-PAPC inhibited bacterial phagocytosis and clearance. However, pre-treatment of OX-PAPC with the monoclonal antibody EO6, which specifically binds to oxidized phospholipid but not native phospholipid, abolished OX-PAPC induced inhibition of bacterial phagocytosis and clearance. Incubation of BALF retrieved from CS-exposed mice impaired bacterial phagocytosis by J774 macrophages, which was abolished by pre-treatment of BALF with the EO6 antibody. In conclusion, our study shows that Ox-PLs generated following chronic CS exposure could play a crucial role in inhibiting phagocytic function of AMs and thus impair pulmonary anti-bacterial innate defenses in CS-exposed mice. Therapeutic approaches that augment pulmonary antioxidant defenses could be beneficial in reducing oxidative stress-driven impairment of phagocytosis by AMs in smokers and COPD patients.

Autoimmunity in chronic obstructive pulmonary disease: clinical and experimental evidence

Over the past few decades, neutrophils and macrophages had co-occupied center stage as the critical innate immune cells underlying the pathobiology of cigarette smoke-induced chronic obstructive pulmonary disease and lung parenchymal destruction (i.e., emphysema). While chronic exposure to smoke facilitates the recruitment of innate immune cells into the lung, a clear role for adaptive immunity in emphysema has emerged. Evidence from human studies specifically point to a role for recruitment and activation of pathogenic lymphocytes and lung antigen-presenting cells in emphysema; similarly, animal models have confirmed a significant role for autoimumnity in progressive smoke-induced emphysema. Increased numbers of activated antigen-presenting cells, Th1 and Th17 cells, have been associated with smoke-induced lung inflammation and production of the canonical cytokines of these cells, IFN-γ and IL-17, correlates with disease severity. These exciting new breakthroughs could open new avenues for developing effective new therapies for smoke-induced emphysema.

Intratracheal bleomycin causes airway remodeling and airflow obstruction in mice

In addition to parenchymal fibrosis, fibrotic remodeling of the distal airways has been reported in interstitial lung diseases. Mechanisms of airway wall remodeling, which occurs in a variety of chronic lung diseases, are not well defined and current animal models are limited. The authors quantified airway remodeling in lung sections from subjects with idiopathic pulmonary fibrosis (IPF) and controls. To investigate intratracheal bleomycin as a potential animal model for fibrotic airway remodeling, the authors evaluated lungs from C57BL/6 mice after bleomycin treatment by histologic scoring for fibrosis and peribronchial inflammation, morphometric evaluation of subepithelial connective tissue volume density, TUNEL (terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling) assay, and immunohistochemistry for transforming growth factor β1 (TGFβ1), TGFβ2, and the fibroblast marker S100A4. Lung mechanics were determined at 3 weeks post bleomycin. IPF lungs had small airway remodeling with increased bronchial wall thickness compared to controls. Similarly, bleomycin-treated mice developed dose-dependent airway wall inflammation and fibrosis and greater airflow resistance after high-dose bleomycin. Increased TUNEL(+) bronchial epithelial cells and peribronchial inflammation were noted by 1 week, and expression of TGFβ1 and TGFβ2 and accumulation of S100A4(+) fibroblasts correlated with airway remodeling in a bleomycin dose-dependent fashion. IPF is characterized by small airway remodeling in addition to parenchymal fibrosis, a pattern also seen with intratracheal bleomycin. Bronchial remodeling from intratracheal bleomycin follows a cascade of events including epithelial cell injury, airway inflammation, profibrotic cytokine expression, fibroblast accumulation, and peribronchial fibrosis. Thus, this model can be utilized to investigate mechanisms of airway remodeling.

Suppressed expression of T-box transcription factors is involved in senescence in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major global health problem. The etiology of COPD has been associated with apoptosis, oxidative stress, and inflammation. However, understanding of the molecular interactions that modulate COPD pathogenesis remains only partly resolved. We conducted an exploratory study on COPD etiology to identify the key molecular participants. We used information-theoretic algorithms including Context Likelihood of Relatedness (CLR), Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNE), and Inferelator. We captured direct functional associations among genes, given a compendium of gene expression profiles of human lung epithelial cells. A set of genes differentially expressed in COPD, as reported in a previous study were superposed with the resulting transcriptional regulatory networks. After factoring in the properties of the networks, an established COPD susceptibility locus and domain-domain interactions involving protein products of genes in the generated networks, several molecular candidates were predicted to be involved in the etiology of COPD. These include COL4A3, CFLAR, GULP1, PDCD1, CASP10, PAX3, BOK, HSPD1, PITX2, and PML. Furthermore, T-box (TBX) genes and cyclin-dependent kinase inhibitor 2A (CDKN2A), which are in a direct transcriptional regulatory relationship, emerged as preeminent participants in the etiology of COPD by means of senescence. Contrary to observations in neoplasms, our study reveals that the expression of genes and proteins in the lung samples from patients with COPD indicate an increased tendency towards cellular senescence. The expression of the anti-senescence mediators TBX transcription factors, chromatin modifiers histone deacetylases, and sirtuins was suppressed; while the expression of TBX-regulated cellular senescence markers such as CDKN2A, CDKN1A, and CAV1 was elevated in the peripheral lung tissue samples from patients with COPD. The critical balance between senescence and anti-senescence factors is disrupted towards senescence in COPD lungs.

Pathobiologic mechanisms of chronic obstructive pulmonary disease

COPD is a worldwide public health problem that reduces the quality of life. The exact pathways by which CS and other environmental toxins produce COPD are not known. Currently, the leading candidates are (1) the protease-antiprotease hypothesis, (2) the Dutch hypothesis, (3) the British hypothesis, and the (4) autoimmunity hypothesis. Given the heterogeneity of the disease (and phenotypes), it is probably unrealistic that one pathway will fully explain COPD pathophysiology.

Vessel-associated transforming growth factor-beta1 (TGF-β1) is increased in the bronchial reticular basement membrane in COPD and normal smokers

BACKGROUND

Transforming growth factor-beta1 (TGF-β1) is a multipotential cytokine with angiogenic activity. There are only limited data about its role in airway remodeling in COPD. We have previously shown that the reticular basement membrane (Rbm) is hypervascular in the airways of current smokers either with or without chronic obstructive pulmonary disease (COPD). This study evaluated TGF-β1 immunostaining in the Rbm and its relationship to vascularity in smokers with or without COPD.

METHODOLOGY/PRINCIPAL FINDINGS

Bronchial biopsies from 15 smokers with normal lung function, 19 current and 14 ex-smokers with COPD were immunostained for TGF-β1 antibody and compared to 17 healthy controls. The percentage area of tissue and also number and area of vessels staining positively for TGF-β1 were measured and compared between groups. Some bronchial biopsies from current smoking COPD subjects were also stained for phosphorylated (active) Smad2/3. Epithelial TGF- β1 staining was not different between COPD current smokers and normal controls. TGF-β1 stained vessels in the Rbm were increased in smokers with normal lung function, current smoking COPD and ex-smokers with COPD compared to controls [median (range) for number of vessels/mm Rbm 2.5 (0.0-12.7), 3.4 (0.0-8.1) and 1.0 (0.0-6.3) vs. 0.0 (0.0-7.0), p<0.05]. Percentage of vessels stained was also increased in these clinical groups. Preliminary data suggest that in current smoking COPD subjects endothelial cells and cells in the Rbm stain positively for phosphorylated Smad2/3 suggesting TGF-β1 is functionally active in this situation.

CONCLUSIONS/SIGNIFICANCE

Vessel-associated TGF-β1 activity is increased in the bronchial Rbm in smokers and especially those with COPD.

IL-18 induces emphysema and airway and vascular remodeling via IFN-γ, IL-17A, and IL-13

RATIONALE

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, alveolar destruction, and airway and vascular remodeling. However, the mechanisms that lead to these diverse alterations have not been defined.

OBJECTIVES

We hypothesized that IL-18 plays a central role in the pathogenesis of these lesions.

METHODS

We generated and characterized lung-specific, inducible IL-18 transgenic mice.

MEASUREMENTS AND MAIN RESULTS

Here we demonstrate that the expression of IL-18 in the mature murine lung induces inflammation that is associated with the accumulation of CD4(+), CD8(+), CD19(+), and NK1.1(+) cells; emphysema; mucus metaplasia; airway fibrosis; vascular remodeling; and right ventricle cardiac hypertrophy. We also demonstrate that IL-18 induces type 1, type 2, and type 17 cytokines with IFN-γ-inhibiting macrophage, lymphocyte, and eosinophil accumulation while stimulating alveolar destruction and genes associated with cell cytotoxicity and IL-13 and IL-17A inducing mucus metaplasia, airway fibrosis, and vascular remodeling. We also highlight interactions between these responses with IL-18 inducing IL-13 via an IL-17A-dependent mechanism and the type 1 and type17/type 2 responses counterregulating each another.

CONCLUSIONS

These studies define the spectrum of inflammatory, parenchymal, airway, and vascular alterations that are induced by pulmonary IL-18; highlight the similarities between these responses and the lesions in COPD; and define the selective roles that type 1, type 2, and type 17 responses play in the generation of IL-18-induced pathologies.

Acute exacerbations of chronic obstructive pulmonary disease in the emergency department

Chronic obstructive pulmonary disease (COPD) is a significant cause of morbidity and mortality worldwide. Acute exacerbations of COPD (AECOPDs) are a common presentation to emergency departments and are an important cause of respiratory failure. This article discusses the disease process and diagnosis of COPD and AECOPD. A further in-depth discussion is undertaken of evidence-based treatments, palliation, and disposition of patients who present to emergency departments with AECOPD.

Modulation of bacterial pathogenesis by oppressive aging factors: insights into host-pneumococcal interaction strategies

Streptococcus pneumonia, (Spn, the pneumococcus), is the leading cause of community-acquired pneumonia (CAP) and is responsible for 15–40% deaths in the elderly worldwide. A primed inflammatory status is a significant risk factor for the increased severity of infectious diseases among the elderly (≥65 years of age). Studies have shown that expression of host receptors that the pneumococci bind to invade the tissues are increased thereby increasing the susceptibility to pneumococcal challenge in aged mice. Cellular senescence, an age-related phenomenon that leads to cell cycle arrest may also contribute to increased inflammation in aged mice. Evidence of cellular senescence in aged lungs of humans and mice adds credits to the concept of inflammaging and enhanced bacterial ligands expression during aging. Furthermore, cell senescence has been shown to occur in age-associated lung pathologies such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that may predispose the elderly to pathogenic assaults, including S. pneumoniae. This review highlights the aspects of: chronic inflammation in the aged population; contribution of cellular senescence to age-associated inflammation and their impact on host receptor expression; and, increased susceptibility of fibrosis and emphysematous lesions-bearing lungs to microbial infections.

Role for TAK1 in cigarette smoke-induced proinflammatory signaling and IL-8 release by human airway smooth muscle cells

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease, characterized by a progressive decline in lung function. Airway smooth muscle (ASM) mass may be increased in COPD, contributing to airflow limitation and proinflammatory cytokine production. Cigarette smoke (CS), the major risk factor of COPD, causes ASM cell proliferation, as well as interleukin-8 (IL-8)-induced neutrophilia. In various cell types, transforming growth factor-β-activated kinase 1 (TAK1) plays a crucial role in MAP kinase and NF-κB activation, as well as IL-8 release induced by IL-1β, TNF-α, and lipopolysaccharide. The role of TAK1 in CS-induced IL-8 release is not known. The aim of this study was to investigate the role of TAK1 in CS-induced NF-κB and MAP kinase signaling and IL-8 release by human ASM cells. Stimulation of these cells with CS extract (CSE) increased IL-8 release and ERK-1/2 phosphorylation, as well as Iκ-Bα degradation and p65 NF-κB subunit phosphorylation. CSE-induced ERK-1/2 phosphorylation and Iκ-Bα degradation were both inhibited by pretreatment with the specific TAK1 inhibitor LL-Z-1640-2 (5Z-7-oxozeaenol; 100 nM). Similarly, expression of dominant-negative TAK1 inhibited CSE-induced ERK-1/2 phosphorylation. In addition, inhibitors of TAK1 and the NF-κB (SC-514; 50 μM) and ERK-1/2 (U-0126; 3 μM) signaling inhibited the CSE-induced IL-8 release by ASM cells. These data indicate that TAK1 plays a major role in CSE-induced ERK-1/2 and NF-κB signaling and in IL-8 release by human ASM cells. Furthermore, they identify TAK1 as a novel target for the inhibition of CS-induced inflammatory responses involved in the development and progression of COPD.

Inhibitory effects of theophylline on the peroxynitrite-augmented release of matrix metalloproteinases by lung fibroblasts

The anti-inflammatory effects of theophylline have been reported to include inhibition of the release of proinflammatory mediators from macrophages and neutrophils. Overproduction of reactive nitrogen species (RNS) has been reported in the airways of patients with chronic obstructive pulmonary disease (COPD), and this causes tissue inflammation and injury. We investigated whether peroxynitrite stimulated the release of matrix metalloproteinases 2 and 9 (MMP-2 and -9; gelatinases) from human fetal lung fibroblasts (HFL-1 cell line) and whether theophylline inhibited the peroxynitrite-augmented release of MMPs. HFL-1 cells and primary lung fibroblasts were treated with peroxynitrite (an RNS), and gelatinases levels were evaluated by gelatin zymography. The inhibitory effect of theophylline on the peroxynitrite-augmented release of MMP-2 and MMP-9 was also investigated. To explore the cell signaling pathways involved in the peroxynitrite-induced gelatinases release and the inhibitory effect of theophylline, transforming growth factor-β1 (TGF-β1), nuclear factor-κB (NF-κB), and histone deacetylase (HDAC) were measured. Peroxynitrite significantly augmented the release of MMP-2 and MMP-9 by fibroblasts ( P < 0.01), as well as TGF-β1 release ( P < 0.01), NF-κB activation ( P < 0.01), and HDAC2 inactivation ( P < 0.01). An NF-κB inhibitor diminished the RNS-augmented release of MMPs and TGF-β1 ( P < 0.01), and a neutralizing TGF-β antibody also diminished MMP release ( P < 0.01). Theophylline significantly inhibited the peroxynitrite-augmented release of MMP-2 and MMP-9 in HFL-1 cells and normal adult lung fibroblasts, and it also inhibited the peroxynitrite-mediated HDAC2 inactivation, NF-κB activation, and TGF-β1 release in HFL-1 cells (all P < 0.01). These results suggest that peroxynitrite can influence tissue remodeling by promoting gelatinases release, while theophylline suppresses peroxynitrite-induced tissue remodeling via pathways involving NF-κB/TGF-β1 and/or HDAC in the HFL-1 cell line.

Chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterised by progressive airflow obstruction that is only partly reversible, inflammation in the airways, and systemic effects or comorbities. The main cause is smoking tobacco, but other factors have been identified. Several pathobiological processes interact on a complex background of genetic determinants, lung growth, and environmental stimuli. The disease is further aggravated by exacerbations, particularly in patients with severe disease, up to 78% of which are due to bacterial infections, viral infections, or both. Comorbidities include ischaemic heart disease, diabetes, and lung cancer. Bronchodilators constitute the mainstay of treatment: β(2) agonists and long-acting anticholinergic agents are frequently used (the former often with inhaled corticosteroids). Besides improving symptoms, these treatments are also thought to lead to some degree of disease modification. Future research should be directed towards the development of agents that notably affect the course of disease.

A NOD2 gene polymorphism is associated with the prevalence and severity of chronic obstructive pulmonary disease in a Japanese population

BACKGROUND AND OBJECTIVE

Genetic background is thought to be one of the risk factors for development of COPD. Recently, it has been proposed that the innate immune system is involved in the pathophysiology of COPD. We hypothesized that polymorphisms in the nucleotide-binding and oligomerization domain (NOD)1 and NOD2 genes would be associated with the pathogenesis of COPD. In addition, the associations between these single nucleotide polymorphisms (SNPs) and phenotypes of COPD were analysed.

METHODS

Japanese COPD patients (n = 228) and non-COPD smokers (n = 101) were recruited from the outpatient clinic at Kyoto University Hospital, Kyoto, Japan. At entry into the study, a blood sample was taken and a pulmonary function test was performed. Genotyping was performed for 6 selected tag SNPs of NOD1 and 5 tag SNPs of NOD2. Further investigations were performed for SNP that were associated with COPD, including baseline gene expression, the relative proportions of splicing variants in whole blood, responses to ligand and enhancement of gene expression in peripheral blood neutrophils stimulated with pro-inflammatory cytokines.

RESULTS

The distribution of NOD2 rs1077861 genotypes differed between Japanese COPD patients and non-COPD smokers (P = 0.036). This SNP was also associated with a lower FEV(1) % predicted (57.2 ± 1.8 for TT vs 50.8 ± 2.3 for TA/AA, P = 0.03) and DL(CO) /V(A) (2.89 ± 0.1 in TT vs 2.53 ± 0.14 in TA/AA, P = 0.036) in COPD patients. NOD2 gene expression after stimulation with 10 ng/mL of tumour necrosis factor-α for 4 h, was increased to a greater extent in TA/AA genotype than in TT genotype peripheral blood neutrophils (P = 0.015).

CONCLUSIONS

The NOD2 rs1077861 SNP may influence the development and progression of COPD in Japanese subjects.

Anti-inflammatory role of the cAMP effectors Epac and PKA: implications in chronic obstructive pulmonary disease

Cigarette smoke-induced release of pro-inflammatory cytokines including interleukin-8 (IL-8) from inflammatory as well as structural cells in the airways, including airway smooth muscle (ASM) cells, may contribute to the development of chronic obstructive pulmonary disease (COPD). Despite the wide use of pharmacological treatment aimed at increasing intracellular levels of the endogenous suppressor cyclic AMP (cAMP), little is known about its exact mechanism of action. We report here that next to the β(2)-agonist fenoterol, direct and specific activation of either exchange protein directly activated by cAMP (Epac) or protein kinase A (PKA) reduced cigarette smoke extract (CSE)-induced IL-8 mRNA expression and protein release by human ASM cells. CSE-induced IκBα-degradation and p65 nuclear translocation, processes that were primarily reversed by Epac activation. Further, CSE increased extracellular signal-regulated kinase (ERK) phosphorylation, which was selectively reduced by PKA activation. CSE decreased Epac1 expression, but did not affect Epac2 and PKA expression. Importantly, Epac1 expression was also reduced in lung tissue from COPD patients. In conclusion, Epac and PKA decrease CSE-induced IL-8 release by human ASM cells via inhibition of NF-κB and ERK, respectively, pointing at these cAMP effectors as potential targets for anti-inflammatory therapy in COPD. However, cigarette smoke exposure may reduce anti-inflammatory effects of cAMP elevating agents via down-regulation of Epac1.

Antibiotics as immunomodulant agents in COPD

It is widely accepted that some antibiotics have activities beyond their direct antibacterial effects. Macrolide is the antibiotic class with more convincing studies and evidence on its immunomodulatory and anti-inflammatory activities. Different clinical studies have shown that macrolide prophylaxis in patients with moderate-severe chronic obstructive pulmonary disease (COPD) can have a significant impact on the exacerbation rate reducing morbidity and, potentially, mortality of the disease. Other antibiotics, such as fluoroquinolones, demonstrate a variety of immunomodulatory effects but only few clinical data are available in COPD. New macrolide derivatives devoid of antibacterial activity have been synthetized. This review analyses the relevance of immunomodulatory and anti-inflammatory effects of antibiotics in the management of COPD.

Low dose theophylline showed an inhibitory effect on the production of IL-6 and IL-8 in primary lung fibroblast from patients with COPD

Chronic obstructive pulmonary disease (COPD) is characterized by the abnormal and chronic lung inflammation. We hypothesized that lung fibroblasts could contribute to the local inflammation and investigated whether low dose theophylline had a beneficial effect on fibroblasts inflammation. Subjects undergoing lobectomy for bronchial carcinoma were enrolled and divided into COPD and control groups according to spirometry. Primary human lung fibroblasts were cultured from peripheral lung tissue distant to tumor tissue. There was a significant increase in both the mRNA expressions and protein levels for IL-6 and IL-8 in fibroblasts in COPD group, and the values were negatively correlated with lung function (P < 0.05). For COPD fibroblasts, the protein levels of IL-6 and IL-8 decreased from 993.0 ± 738.9 pg/mL to 650.1 ± 421.9 pg/mL (P = 0.014) and from 703.1 ± 278.0 pg/mL to 492.0 ± 214.9 pg/mL (P = 0.001), respectively, with 5 μg/mL theophylline treatment. In addition, theophylline at the dose of 5 μg/mL reduced the increased production of IL-6 and IL-8 induced by 1 μg/mL LPS in primary human lung fibroblasts. Our data suggest that lung fibroblasts participate in the chronic inflammation in COPD by releasing IL-6 and IL-8, and low dose theophylline can alleviate the proinflammatory mediators' production by fibroblasts.

The pathogenesis of COPD and IPF: distinct horns of the same devil?

New paradigms have been recently proposed in the pathogenesis of both chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), evidencing surprising similarities between these deadly diseases, despite their obvious clinical, radiological and pathologic differences. There is growing evidence supporting a "double hit" pathogenic model where in both COPD and IPF the cumulative action of an accelerated senescence of pulmonary parenchyma (determined by either telomere dysfunction and/or a variety of genetic predisposing factors), and the noxious activity of cigarette smoke-induced oxidative damage are able to severely compromise the regenerative potential of two pulmonary precursor cell compartments (alveolar epithelial precursors in IPF, mesenchymal precursor cells in COPD/emphysema). The consequent divergent derangement of signalling pathways involved in lung tissue renewal (mainly Wnt and Notch), can eventually lead to the distinct abnormal tissue remodelling and functional impairment that characterise the alveolar parenchyma in these diseases (irreversible fibrosis and bronchiolar honeycombing in IPF, emphysema and airway chronic inflammation in COPD).

Nicotinic acetylcholine receptor variants associated with susceptibility to chronic obstructive pulmonary disease: a meta-analysis

Background

Only 10-15% of smokers develop chronic obstructive pulmonary disease (COPD) which indicates genetic susceptibility to the disease. Recent studies suggested an association between COPD and polymorphisms in CHRNA coding subunits of nicotinic acetylcholine receptor. Herein, we performed a meta-analysis to clarify the impact of CHRNA variants on COPD.

Methods

We searched Web of Knowledge and Medline from 1990 through June 2011 for COPD gene studies reporting variants on CHRNA. Pooled odds ratios (ORs) were calculated using the major allele or genotype as reference group.

Results

Among seven reported variants in CHRNA, rs1051730 was finally analyzed with sufficient studies. Totally 3460 COPD and 11437 controls from 7 individual studies were pooled-analyzed. A-allele of rs1051730 was associated with an increased risk of COPD regardless of smoking exposure (pooled OR = 1.26, 95% CI 1.18-1.34, p < 10^-5). At the genotypic level, the ORs gradually increased per A-allele (OR = 1.27 and 1.50 for GA and AA respectively, p < 10^-5). Besides, AA genotype exhibited an association with reduced FEV1% predicted (mean difference 3.51%, 95%CI 0.87-6.16%, p = 0.009) and increased risk of emphysema (OR 1.93, 95%CI 1.29-2.90, p = 0.001).

Conclusions

Our findings suggest that rs1051730 in CHRNA is a susceptibility variant for COPD, in terms of both airway obstruction and parenchyma destruction.

[Protective role of Nrf2 in the lungs against oxidative airway diseases]

Airways are continually exposed to multiple inhaled oxidants and protect themselves with cellular and extracellular antioxidants throughout the epithelial lining fluid and tissues. Oxidative stress, resulting from the increased oxidative burden and decreased level of antioxidant proteins, is involved in cellular and tissue damage related to the pathogenesis of many acute and chronic respiratory diseases. Evidence suggested that nuclear factor erythroid-2-related factor 2 (Nrf2), a transcription factor that controls antioxidant response element (ARE)-regulated antioxidant and cytoprotective genes has an essential protective role in the lungs against oxidative airway diseases. Therefore, Nrf2 promises to be an attractive therapeutic target for intervention and prevention strategies in respiratory diseases. We have reviewed major findings on the mechanisms of lung protection against oxidative stress by Nrf2 and the current literature suggesting that Nrf2 is a valuable therapeutic target.

Sputum proteomics identifies elevated PIGR levels in smokers and mild-to-moderate COPD

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality around the world. However, the exact mechanisms leading to COPD and its progression are still poorly understood. In this study, induced sputum was analyzed by cysteine-specific two-dimensional difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry to identify proteins involved in COPD pathogenesis. The comparison of nonsmokers, smokers, and smokers with moderate COPD revealed 15 changed proteins with the majority, including polymeric immunoglobulin receptor (PIGR), being elevated in smokers and subjects with COPD. PIGR, which is involved in specific immune defense and inflammation, was further studied in sputum, lung tissue, and plasma by Western blot, immunohistochemistry/image analysis, and/or ELISA. Sputum PIGR was characterized as glycosylated secretory component (SC). Lung PIGR was significantly elevated in the bronchial and alveolar epithelium of smokers and further increased in the alveolar area in mild to moderate COPD. Plasma PIGR was elevated in smokers and smokers with COPD compared to nonsmokers with significant correlation to obstruction. In conclusion, new proteins in smoking-related chronic inflammation and COPD could be identified, with SC/PIGR being one of the most prominent not only in the lung but also in circulating blood.

Denitrosylation of HDAC2 by targeting Nrf2 restores glucocorticosteroid sensitivity in macrophages from COPD patients

Chronic obstructive pulmonary disease (COPD), which is caused primarily by cigarette smoking, is a major health problem worldwide. The progressive decline in lung function that occurs in COPD is a result of persistent inflammation of the airways and destruction of the lung parenchyma. Despite the key role of inflammation in the pathogenesis of COPD, treatment with corticosteroids - normally highly effective antiinflammatory drugs - has little therapeutic benefit. This corticosteroid resistance is largely caused by inactivation of histone deacetylase 2 (HDAC2), which is critical for the transrepressive activity of the glucocorticoid receptor (GR) that mediates the antiinflammatory effect of corticosteroids. Here, we show that in alveolar macrophages from patients with COPD, S-nitrosylation of HDAC2 is increased and that this abolishes its GR-transrepression activity and promotes corticosteroid insensitivity. Cys-262 and Cys-274 of HDAC2 were found to be the targets of S-nitrosylation, and exogenous glutathione treatment of macrophages from individuals with COPD restored HDAC2 activity. Treatment with sulforaphane, a small-molecule activator of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), was also able to denitrosylate HDAC2, restoring dexamethasone sensitivity in alveolar macrophages from patients with COPD. These effects of sulforaphane were glutathione dependent. We conclude that NRF2 is a novel drug target for reversing corticosteroid resistance in COPD and other corticosteroid-resistant inflammatory diseases.

Cigarette smoke exposure induces CFTR internalization and insolubility, leading to airway surface liquid dehydration

Cigarette smoke (CS) exposure induces mucus obstruction and the development of chronic bronchitis (CB). While many of these responses are determined genetically, little is known about the effects CS can exert on pulmonary epithelia at the protein level. We, therefore, tested the hypothesis that CS exerts direct effects on the CFTR protein, which could impair airway hydration, leading to the mucus stasis characteristic of both cystic fibrosis and CB. In vivo and in vitro studies demonstrated that CS rapidly decreased CFTR activity, leading to airway surface liquid (ASL) volume depletion (i.e., dehydration). Further studies revealed that CS induced internalization of CFTR. Surprisingly, CS-internalized CFTR did not colocalize with lysosomal proteins. Instead, the bulk of CFTR shifted to a detergent-resistant fraction within the cell and colocalized with the intermediate filament vimentin, suggesting that CS induced CFTR movement into an aggresome-like, perinuclear compartment. To test whether airway dehydration could be reversed, we used hypertonic saline (HS) as an osmolyte to rehydrate ASL. HS restored ASL height in CS-exposed, dehydrated airway cultures. Similarly, inhaled HS restored mucus transport and increased clearance in patients with CB. Thus, we propose that CS exposure rapidly impairs CFTR function by internalizing CFTR, leading to ASL dehydration, which promotes mucus stasis and a failure of mucus clearance, leaving smokers at risk for developing CB. Furthermore, our data suggest that strategies to rehydrate airway surfaces may provide a novel form of therapy for patients with CB.