Cellular and molecular mechanisms in chronic obstructive pulmonary disease: an overview

Global Research Trends on the Link Between the Microbiome and COPD: A Bibliometric Analysis

Background

The pathogenesis of chronic obstructive pulmonary disease (COPD) has been studied in relation to the microbiome, providing space for more targeted interventions and new treatments. Numerous papers on the COPD microbiome have been reported in the last 10 years, yet few publications have used bibliometric methods to evaluate this area.

Methods

We searched the Web of Science Core Collection for all original research articles in the field of COPD microbiome from January 2011 to August 2022 and used CiteSpace for visual analysis.

Results

A total of 505 relevant publications were obtained, and the number of global publications in this field is steadily increasing every year, with China and the USA occupying the first two spots in international publications. Imperial College London and the University of Leicester produced the most publications. Brightling C from the UK was the most prolific writer, while Huang Y and Sze M from the USA were first and second among the authors cited. The American Journal of Respiratory and Critical Care Medicine had the highest frequency of citations. The top 10 institutions, cited authors and journals are mostly from the UK and the US. In the ranking of citations, the first article was a paper published by Sze M on changes in the lung tissue's microbiota in COPD patients. The keywords "exacerbation", "gut microbiota", "lung microbiome", "airway microbiome", "bacterial colonization", and "inflammation" were identified as cutting-edge research projects for 2011-2022.

Conclusion

Based on the visualization results, in the future, we can use the gut-lung axis as the starting point to explore the immunoinflammatory mechanism of COPD, and study how to predict the effects of different treatments of COPD by identifying the microbiota, and how to achieve the optimal enrichment of beneficial bacteria and the optimal consumption of harmful bacteria to improve COPD.

Seabuckthorn Wuwei Pulvis attenuates chronic obstructive pulmonary disease in rat through gut microbiota-short chain fatty acids axis

ETHNOPHARMACOLOGICAL RELEVANCE

Seabuckthorn Wuwei Pulvis (SWP) is a traditional Mongolian medicine used in China. It is composed of Hippophae rhamnoides (berries, 30 g), Aucklandiae costus Falc. (dry root, 25 g), Vitis vinifera F. Cordifolia (berries, 20 g), Glycyrrhiza uralensis Fisch. (dry root, 15 g), and Gardenia jasminoides J. Ellis (desiccative ripe fruit, 10 g). It is clinically applied in the treatment of chronic cough, shortness of breath and phlegm, and chest distress. Past studies demonstrated that Seabuckthorn Wuwei Pulvis improved lung inflammation and chronic bronchitis in mice. However, the effect of Seabuckthorn Wuwei Pulvis on chronic obstructive pulmonary disease (COPD) in rats and the underlying action mechanism is not fully understood.

AIM OF THE STUDY

To evaluate the anti-COPD effect of Seabuckthorn Wuwei Pulvis and investigate whether its ameliorative effect is correlated with the composition of gut microbiota and its metabolites.

MATERIALS AND METHODS

The effects of Seabuckthorn Wuwei Pulvis on a COPD rat model were established by exposure to lipopolysaccharide (LPS) and smoking. These effects were then evaluated by monitoring the animal weight, pulmonary function, lung histological alteration, and the levels of inflammatory factors (tumor necrotic factor [TNF]-α, interleukin [IL]-8, IL-6, and IL-17). Furthermore, the serum LPS and fluorescein isothiocyanate-dextran levels were detected by using an enzyme-linked immunosorbent assay and fluorescence microplate reader, respectively. Tight junction proteins (ZO-1 and occludin-1) in the small intestine were detected by performing real-time quantitative polymerase chain reactions and Western blotting to evaluate the intestinal barrier function. The contents of short-chain fatty acids (SCFAs) in the feces of rats were determined by gas chromatography-mass spectrometry. 16S rDNA high throughput sequencing was used to investigate the effect of SWP on the gut microbiota of COPD rats.

RESULTS

Treatment with low and median doses of SWP significantly increased the pulmonary function (forced expiratory volume [FEV] 0.3, forced vital capacity [FVC], and FEV0.3/FVC), decreased the levels of TNF-α, IL-8, IL-6, and IL-17 in the lung, and attenuated the infiltration of inflammatory cells into the lung. The low and median doses of SWP shaped the composition of gut microbiota, which increased the abundances of Ruminococcaceae, Christensenellaceae, and Aerococcaceae, increased the productions of acetic acid, propionic acid, and butyric acid, and upregulated the expression of ZO-1 and occludin-1 in the small intestine of COPD rats.

CONCLUSION

SWP improved pulmonary functions and inhibited the inflammatory response by shaping the gut microbiota, increasing SCFA production, and strengthening the intestinal barrier function in rats with COPD induced by LPS and smoking.

Expanding role of deoxyribonucleic acid-sensing mechanism in the development of lifestyle-related diseases

In lifestyle-related diseases, such as cardiovascular, metabolic, respiratory, and kidney diseases, chronic inflammation plays a causal role in their pathogenesis; however, underlying mechanisms of sterile chronic inflammation are not well-understood. Previous studies have confirmed the damage of cells in these organs in the presence of various risk factors such as diabetes, dyslipidemia, and cigarette smoking, releasing various endogenous ligands for pattern recognition receptors. These studies suggested that nucleic acids released from damaged tissues accumulate in these tissues, acting as an endogenous ligand. Undamaged DNA is an integral factor for the sustenance of life, whereas, DNA fragments, especially those from pathogens, are potent activators of the inflammatory response. Recent studies have indicated that inflammatory responses such as the production of type I interferon (IFN) induced by DNA-sensing mechanisms which contributes to self-defense system in innate immunity participates in the progression of inflammatory diseases by the recognition of nucleic acids derived from the host, including mitochondrial DNA (mtDNA). The body possesses several types of DNA sensors. Toll-like receptor 9 (TLR9) recognizes DNA fragments in the endosomes. In addition, the binding of DNA fragments in the cytosol activates cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS), resulting in the synthesis of the second messenger cyclic GMP-AMP (cGAMP). The binding of cGAMP to stimulator of interferon genes (STING) activates NF-κB and TBK-1 signaling and consequently the production of many inflammatory cytokines including IFNs. Numerous previous studies have demonstrated the role of DNA sensors in self-defense through the recognition of DNA fragments derived from pathogens. Beyond the canonical role of TLR9 and cGAS-STING, this review describes the role of these DNA-sensing mechanism in the inflammatory responses caused by endogenous DNA fragments, and in the pathogenesis of lifestyle-related diseases.

Therapeutic Potential of Small Molecules Targeting Oxidative Stress in the Treatment of Chronic Obstructive Pulmonary Disease (COPD): A Comprehensive Review

Chronic obstructive pulmonary disease (COPD) is an increasing and major global health problem. COPD is also the third leading cause of death worldwide. Oxidative stress (OS) takes place when various reactive species and free radicals swamp the availability of antioxidants. Reactive nitrogen species, reactive oxygen species (ROS), and their counterpart antioxidants are important for host defense and physiological signaling pathways, and the development and progression of inflammation. During the disturbance of their normal steady states, imbalances between antioxidants and oxidants might induce pathological mechanisms that can further result in many non-respiratory and respiratory diseases including COPD. ROS might be either endogenously produced in response to various infectious pathogens including fungi, viruses, or bacteria, or exogenously generated from several inhaled particulate or gaseous agents including some occupational dust, cigarette smoke (CS), and air pollutants. Therefore, targeting systemic and local OS with therapeutic agents such as small molecules that can increase endogenous antioxidants or regulate the redox/antioxidants system can be an effective approach in treating COPD. Various thiol-based antioxidants including fudosteine, erdosteine, carbocysteine, and N-acetyl-L-cysteine have the capacity to increase thiol content in the lungs. Many synthetic molecules including inhibitors/blockers of protein carbonylation and lipid peroxidation, catalytic antioxidants including superoxide dismutase mimetics, and spin trapping agents can effectively modulate CS-induced OS and its resulting cellular alterations. Several clinical and pre-clinical studies have demonstrated that these antioxidants have the capacity to decrease OS and affect the expressions of several pro-inflammatory genes and genes that are involved with redox and glutathione biosynthesis. In this article, we have summarized the role of OS in COPD pathogenesis. Furthermore, we have particularly focused on the therapeutic potential of numerous chemicals, particularly antioxidants in the treatment of COPD.

Moraxella catarrhalis evades neutrophil oxidative stress responses providing a safer niche for nontypeable Haemophilus influenzae

Moraxella catarrhalis and nontypeable Haemophilus influenzae (NTHi) are pathogenic bacteria frequently associated with exacerbation of chronic obstructive pulmonary disease (COPD), whose hallmark is inflammatory oxidative stress. Neutrophils produce reactive oxygen species (ROS) which can boost antimicrobial response by promoting neutrophil extracellular traps (NET) and autophagy. Here, we showed that M. catarrhalis induces less ROS and NET production in differentiated HL-60 cells compared to NTHi. It is also able to actively interfere with these responses in chemically activated cells in a phagocytosis and opsonin-independent and contact-dependent manner, possibly by engaging host immunosuppressive receptors. M. catarrhalis subverts the autophagic pathway of the phagocytic cells and survives intracellularly. It also promotes the survival of NTHi which is otherwise susceptible to the host antimicrobial arsenal. In-depth understanding of the immune evasion strategies exploited by these two human pathogens could suggest medical interventions to tackle COPD and potentially other diseases in which they co-exist.

•

Mcat induces ROS and NET production to a lesser extent than NTHi in dHL-60 cells

•

Mcat interferes with ROS-related responses in chemically-activated cells

•

Mcat subverts the autophagic pathway surviving intracellularly while NTHi does not

•

Intracellular survival of NTHi is enhanced by the co-infecting bacterium Mcat

Pathogenesis of COPD at the cellular and molecular level

Chronic inflammatory responses in the lung of patients with stable mild-to severe forms of COPD play a central role in the definition, comprehension and monitoring of the disease state. A better understanding of the COPD pathogenesis can't avoid a detailed knowledge of these inflammatory changes altering the functional health of the lung during the disease progression. We here summarize and discuss the role and principal functions of the inflammatory cells populating the large, small airways and lung parenchyma of patients with COPD of increasing severity in comparison with healthy control subjects: T and B lymphocytes, NK and Innate Lymphoid cells, macrophages, and neutrophils. The differential inflammatory distribution in large and small airways of patients is also discussed. Furthermore, relevant cellular mechanisms controlling the homeostasis and the "normal" balance of these inflammatory cells and of structural cells in the lung, such as autophagy, apoptosis, necroptosis and pyroptosis are as well presented and discussed in the context of the COPD severity.

Bacterial and viral infections and related inflammatory responses in chronic obstructive pulmonary disease

In chronic obstructive pulmonary disease (COPD) patients, bacterial and viral infections play a relevant role in worsening lung function and, therefore, favour disease progression. The inflammatory response to lung infections may become a specific indication of the bacterial and viral infections. We here review data on the bacterial-viral infections and related airways and lung parenchyma inflammation in stable and exacerbated COPD, focussing our attention on the prevalent molecular pathways in these different clinical conditions. The roles of macrophages, autophagy and NETosis are also briefly discussed in the context of lung infections in COPD. Controlling their combined response may restore a balanced lung homeostasis, reducing the risk of lung function decline. KEY MESSAGE Bacteria and viruses can influence the responses of the innate and adaptive immune system in the lung of chronic obstructive pulmonary disease (COPD) patients. The relationship between viruses and bacterial colonization, and the consequences of the imbalance of these components can modulate the inflammatory state of the COPD lung. The complex actions involving immune trigger cells, which activate innate and cell-mediated inflammatory responses, could be responsible for the clinical consequences of irreversible airflow limitation, lung remodelling and emphysema in COPD patients.

Dysregulation of the Immune Environment in the Airways During HIV Infection

HIV-1 increases susceptibility to pulmonary infection and disease, suggesting pathogenesis in the lung. However, the lung immune environment during HIV infection remains poorly characterized. This study examined T cell activation and the cytokine milieu in paired bronchoalveolar lavage (BAL) and blood from 36 HIV-uninfected and 32 HIV-infected participants. Concentrations of 27 cytokines were measured by Luminex, and T cells were phenotyped by flow cytometry. Blood and BAL had distinct cytokine profiles (p=0.001). In plasma, concentrations of inflammatory cytokines like IFN-γ (p=0.004) and TNF-α (p=0.004) were elevated during HIV infection, as expected. Conversely, BAL cytokine concentrations were similar in HIV-infected and uninfected individuals, despite high BAL viral loads (VL; median 48,000 copies/ml epithelial lining fluid). HIV-infected individuals had greater numbers of T cells in BAL compared to uninfected individuals (p=0.007); and BAL VL positively associated with CD4+ and CD8+ T cell numbers (p=0.006 and p=0.0002, respectively) and CXCL10 concentrations (p=0.02). BAL T cells were highly activated in HIV-infected individuals, with nearly 2-3 fold greater frequencies of CD4+CD38+ (1.8-fold; p=0.007), CD4+CD38+HLA-DR+ (1.9-fold; p=0.0006), CD8+CD38+ (2.8-fold; p=0.0006), CD8+HLA-DR+ (2-fold; p=0.022) and CD8+CD38+HLA-DR+ (3.6-fold; p<0.0001) cells compared to HIV-uninfected individuals. Overall, this study demonstrates a clear disruption of the pulmonary immune environment during HIV infection, with readily detectable virus and activated T lymphocytes, which may be driven to accumulate by local chemokines.

Endogenous melatonin mediation of systemic inflammatory responses to ozone exposure in healthy adults

BACKGROUND/AIM

Melatonin is a free radical scavenger and an anti-inflammatory biomolecule. Air pollution exposure has been associated with increased inflammatory responses. We hypothesize that endogenous melatonin plays a role in inflammatory responses to air pollution exposure.

METHODS

We tested this hypothesis in a cohort of 53 healthy adults (22-52 years old, 16 women), none of whom were on melatonin supplementation. Early morning urine and fasting blood were collected from each participant longitudinally up to three times. We analyzed urinary 6-sulfatoxymelatonin (aMT6s), as a surrogate of circulating melatonin, and pro- and anti-inflammatory cytokines in the plasma samples. Indoor and outdoor air pollutants were measured and combined with participants' time-activity patterns to calculate personal exposure to O₃, PM_2.5, NO₂, and SO₂ averaged over 12-hour, 24-hour, 1-week, and 2-week periods prior to biospecimen collection, respectively. Linear mixed-effects models were used to examine the relationships among urinary aMT6s, personal pollutant exposure, and plasma cytokines. A mediation analysis was conducted to examine the role of aMT6s in the relationships between pollutant exposures and inflammatory cytokines.

RESULTS

One interquartile range (4.2 ppb) increase in 2-week O₃ exposure was associated with a -26.2% (95% CI: -43.9% to -2.8%) decrease in aMT6s. Within the range of endogenous aMT6s concentrations (0.5-53.0 ng/ng creatinine) across the participants, increased aMT6s was associated with decreased pro-inflammatory cytokines including IL-1β, IL-8, IL-17A, IFN-γ, and TNF-α. These cytokines were significantly and positively associated with 2-week average O₃ exposure. Furthermore, 7.4% to 17.4% of the O₃-cytokine associations were mediated by aMT6s. We did not find similar effects for the other pollutants.

CONCLUSIONS

Pro-inflammatory responses to O₃ exposure in the preceding 2 weeks partly resulted from the depletion of endogenous melatonin by O₃.

Proteins associated with neutrophil degranulation are upregulated in nasopharyngeal swabs from SARS-CoV-2 patients

COVID-19 or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appeared throughout the World and currently affected more than 9 million people and caused the death of around 470,000 patients. The novel strain of the coronavirus disease is transmittable at a devastating rate with a high rate of severe hospitalization even more so for the elderly population. Naso-oro-pharyngeal swab samples as the first step towards detecting suspected infection of SARS-CoV-2 provides a non-invasive method for PCR testing at a high confidence rate. Furthermore, proteomics analysis of PCR positive and negative naso-oropharyngeal samples provides information on the molecular level which highlights disease pathology. Samples from 15 PCR positive cases and 15 PCR negative cases were analyzed with nanoLC-MS/MS to identify the differentially expressed proteins. Proteomic analyses identified 207 proteins across the sample set and 17 of them were statistically significant. Protein-protein interaction analyses emphasized pathways like Neutrophil degranulation, Innate Immune System, Antimicrobial Peptides. Neutrophil Elastase (ELANE), Azurocidin (AZU1), Myeloperoxidase (MPO), Myeloblastin (PRTN3), Cathepsin G (CTSG) and Transcobalamine-1 (TCN1) were found to be significantly altered in naso-oropharyngeal samples of SARS-CoV-2 patients. The identified proteins are linked to alteration in the innate immune system specifically via neutrophil degranulation and NETosis.

Extracorporeal Shock Waves Increase Markers of Cellular Proliferation in Bronchial Epithelium and in Primary Bronchial Fibroblasts of COPD Patients

Chronic obstructive pulmonary disease (COPD) is due to structural changes and narrowing of small airways and parenchymal destruction (loss of the alveolar attachment as a result of pulmonary emphysema), which all lead to airflow limitation. Extracorporeal shock waves (ESW) increase cell proliferation and differentiation of connective tissue fibroblasts. To date no studies are available on ESW treatment of human bronchial fibroblasts and epithelial cells from COPD and control subjects. We obtained primary bronchial fibroblasts from bronchial biopsies of 3 patients with mild/moderate COPD and 3 control smokers with normal lung function. 16HBE cells were also studied. Cells were treated with a piezoelectric shock wave generator at low energy (0.3 mJ/mm², 500 pulses). After treatment, viability was evaluated and cells were recultured and followed up for 4, 24, 48, and 72 h. Cell growth (WST-1 test) was assessed, and proliferation markers were analyzed by qRT-PCR in cell lysates and by ELISA tests in cell supernatants and cell lysates. After ESW treatment, we observed a significant increase of cell proliferation in all cell types. C-Kit (CD117) mRNA was significantly increased in 16HBE cells at 4 h. Protein levels were significantly increased for c-Kit (CD117) at 4 h in 16HBE (p < 0.0001) and at 24 h in COPD-fibroblasts (p = 0.037); for PCNA at 4 h in 16HBE (p = 0.046); for Thy1 (CD90) at 24 and 72 h in CS-fibroblasts (p = 0.031 and p = 0.041); for TGFβ1 at 72 h in CS-fibroblasts (p = 0.038); for procollagen-1 at 4 h in COPD-fibroblasts (p = 0.020); and for NF-κB-p65 at 4 and 24 h in 16HBE (p = 0.015 and p = 0.0002). In the peripheral lung tissue of a representative COPD patient, alveolar type II epithelial cells (TTF‐1+) coexpressing c-Kit (CD117) and PCNA were occasionally observed. These data show an increase of cell proliferation induced by a low dosage of extracorporeal shock waves in 16HBE cells and primary bronchial fibroblasts of COPD and control smoking subjects.

Androgen and Androgen Receptors as Regulators of Monocyte and Macrophage Biology in the Healthy and Diseased Lung

Androgens, the predominant male sex hormones, drive the development and maintenance of male characteristics by binding to androgen receptor (AR). As androgens are systemically distributed throughout the whole organism, they affect many tissues and cell types in addition to those in male sexual organs. It is now clear that the immune system is a target of androgen action. In the lungs, many immune cells express ARs and are responsive to androgens. In this review, we describe the effects of androgens and ARs on lung myeloid immune cells-monocytes and macrophages-as they relate to health and disease. In particular, we highlight the effect of androgens on lung diseases, such as asthma, chronic obstructive pulmonary disease and lung fibrosis. We also discuss the therapeutic use of androgens and how circulating androgens correlate with lung disease. In addition to human studies, we also discuss how mouse models have helped to uncover the effect of androgens on monocytes and macrophages in lung disease. Although the role of estrogen and other female hormones has been broadly analyzed in the literature, we focus on the new perspectives of androgens as modulators of the immune system that target myeloid cells during lung inflammation.

A cytokine super cyclone in COVID-19 patients with risk factors: the therapeutic potential of BCG immunization

The seventh human coronavirus SARS-CoV2 belongs to the cluster of extremely pathogenic coronaviruses including SARS-CoV and MERS-CoV, which can cause fatal lower respiratory tract infection. Likewise, SARS-CoV2 infection can be fatal as the disease advances to pneumonia, followed by acute respiratory distress syndrome (ARDS). The development of lethal clinical symptons is associated with an exaggerated production of inflammatory cytokines, referred to as the cytokine storm, is a consequence of a hyperactivated immune response aginst the infection. In this article, we discuss the pathogenic consequences of the cytokine storm and its relationship with COVID-19 associated risk factors. The increased pro-inflammatory immune status in patients with risk factors (diabetes, hypertension, cardiovascular disease, COPD) exacerbates the Cytokine-storm of COVID-19 into a 'Cytokine Super Cyclone'. We also evaluate the antiviral immune responses provided by BCG vaccination and the potential role of 'trained immunity' in early protection against SARS-CoV2.

Evaluation of Innate Immune Mediators Related to Respiratory Viruses in the Lung of Stable COPD Patients

Background: Little is known about the innate immune response to viral infections in stable Chronic Obstructive Pulmonary Disease (COPD). Objectives: To evaluate the innate immune mediators related to respiratory viruses in the bronchial biopsies and lung parenchyma of stable COPD patients. Methods: We evaluated the immunohistochemical (IHC) expression of Toll-like receptors 3-7-8-9 (TLR-3-7-8-9), TIR domain-containing adaptor inducing IFNβ (TRIF), Interferon regulatory factor 3 (IRF3), Phospho interferon regulatory factor 3 (pIRF3), Interferon regulatory factor 7 (IRF7), Phospho interferon regulatory factor 7 (pIRF7), retinoic acid-inducible gene I (RIG1), melanoma differentiation-associated protein 5 (MDA5), Probable ATP-dependent RNA helicase DHX58 (LGP2), Mitochondrial antiviral-signaling protein (MAVS), Stimulator of interferon genes (STING), DNA-dependent activator of IFN regulatory factors (DAI), forkhead box protein A3(FOXA3), Interferon alfa (IFNα), and Interferon beta (IFNβ) in the bronchial mucosa of patients with mild/moderate (n = 16), severe/very severe (n = 1618) stable COPD, control smokers (CS) (n = 1612), and control non-smokers (CNS) (n = 1612). We performed similar IHC analyses in peripheral lung from COPD (n = 1612) and CS (n = 1612). IFNα and IFNβ were assessed in bronchoalveolar lavage (BAL) supernatant from CNS (n = 168), CS (n = 169) and mild/moderate COPD (n = 1612). Viral load, including adenovirus-B, -C, Bocavirus, Respiratory syncytial Virus (RSV), Human Rhinovirus (HRV), Coronavirus, Influenza virus A (FLU-A), Influenza virus B (FLU-B), and Parainfluenzae-1 were measured in bronchial rings and lung parenchyma of COPD patients and the related control group (CS). Results: Among the viral-related innate immune mediators, RIG1, LGP2, MAVS, STING, and DAI resulted well expressed in the bronchial and lung tissues of COPD patients, although not in a significantly different mode from control groups. Compared to CS, COPD patients showed no significant differences of viral load in bronchial rings and lung parenchyma. Conclusions: Some virus-related molecules are well-expressed in the lung tissue and bronchi of stable COPD patients independently of the disease severity, suggesting a “primed” tissue environment capable of sensing the potential viral infections occurring in these patients.

How Do Innate Immune Cells Contribute to Airway Remodeling in COPD Progression?

Recently, the therapeutic potential of immune-modulation during the progression of chronic obstructive pulmonary disease (COPD) has been attracting increasing interest. However, chronic inflammatory response has been over-simplified in descriptions of the mechanism of COPD progression. As a form of first-line airway defense, epithelial cells exhibit phenotypic alteration, and participate in epithelial layer disorganization, mucus hypersecretion, and extracellular matrix deposition. Dendritic cells (DCs) exhibit attenuated antigen-presenting capacity in patients with advanced COPD. Immature DCs migrate into small airways, where they promote a pro-inflammatory microenvironment and bacterial colonization. In response to damage-associated molecular patterns (DAMPs) in lung tissue affected by COPD, neutrophils are excessively recruited and activated, where they promote a proteolytic microenvironment and fibrotic repair in small airways. Macrophages exhibit decreased phagocytosis in the large airways, while they demonstrate high pro-inflammatory potential in the small airways, and mediate alveolar destruction and chronic airway inflammation. Natural killer T (NKT) cells, eosinophils, and mast cells also play supplementary roles in COPD progression; however, their cellular activities are not yet entirely clear. Overall, during COPD progression, “exhausted” innate immune responses can be observed in the large airways. On the other hand, the innate immune response is enhanced in the small airways. Approaches that inhibit the inflammatory cascade, chemotaxis, or the activation of inflammatory cells could possibly delay the progression of airway remodeling in COPD, and may thus have potential clinical significance.

Salidroside mitigates skeletal muscle atrophy in rats with cigarette smoke-induced COPD by up-regulating myogenin and down-regulating myostatin expression

OBJECTIVES

The present study aimed at investigating the therapeutic effect of Salidroside on skeletal muscle atrophy in a rat model of cigarette smoking-induced chronic obstructive pulmonary disease (COPD) and its potential mechanisms.

METHODS

Male Wistar rats were randomized, and treated intraperitoneally (IP) with vehicle (injectable water) or a low, medium or high dose of Salidroside, followed by exposure to cigarette smoking daily for 16 weeks. A healthy control received vehicle injection and air exposure. Their lung function, body weights and gastrocnemius (GN) weights, grip strength and cross-section area (CSA) of individual muscular fibers in the GN were measured. The levels of TNF-α, IL-6, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) in serum and GN tissues as well as myostatin and myogenin expression in GN tissues were measured.

RESULTS

In comparison with that in the healthy control, long-term cigarette smoking induced emphysema, significantly impaired lung function, reduced body and GN weights and CSA values in rats, accompanied by significantly increased levels of TNF-α, IL-6 and MDA, but decreased levels of SOD and GSH in serum and GN tissues. Furthermore, cigarette smoking significantly up-regulated myostatin expression, but down-regulated myogenin expression in GN tissues. Salidroside treatment decreased emphysema, significantly ameliorated lung function, increased antioxidant, but reduced MDA, IL-6 and TNF-α levels in serum and GN tissues of rats, accompanied by decreased myostain, but increased myogenin expression in GN tissues.

CONCLUSION

Salidroside mitigates the long-term cigarette smoking-induced emphysema and skeletal muscle atrophy in rats by inhibiting oxidative stress and inflammatory responses and regulating muscle-specific transcription factor expression.

Cigarette smoke affects the onco-suppressor DAB2IP expression in bronchial epithelial cells of COPD patients

Cigarette smoke is a risk factor for COPD and lung cancer. In cancer, epigenetic modifications affect the expression of Enhancer of Zester Homolog 2 (EZH2), and silenced disabled homolog 2 interacting protein gene (DAB2IP) (onco-suppressor gene) by Histone H3 tri-methylation in lysine 27 (H3K27me3). In"ex vivo"studies, we assessed EZH2, H3K27me3 and DAB2IP immunoreactivity in bronchial epithelial cells from COPD patients (smokers, ex-smokers), Smoker and control subjects. In"in vitro" experiments we studied the effect of cigarette smoke extract (CSE) on EZH2/H3K27me3/DAB2IP expression, apoptosis, invasiveness, and vimentin expression in 16HBE, primary cells, and lung cancer cell lines (A549) long-term exposed to CSE. Finally, in "in vitro"studies, we tested the effect of GSK343 (selective inhibitor of EZH2). EZH2 and H3K27me3 expression was higher, while DAB2IP was lower levels, in bronchial epithelium from COPD and Smokers than in Controls. CSE increased EZH2, H3K27me3 expression and decreased DAB2IP, cell apoptosis and invasiveness in epithelial cells. GSK343 restored the effects of CSE. Cigarette smoke affects EZH2 expression, and reduced DAB2IP via H3K27me3 in COPD patients. The molecular mechanisms associated with EZH2 expression, generate a dysregulation of cell apoptosis, mesenchymal transition, and cell invasiveness in bronchial epithelial cells, encouraging the progression of airway inflammation toward lung cancer in COPD patients.

The study of genes and signal transduction pathways involved in mustard lung injury: A gene therapy approach

Sulfur mustard (SM) is a destructive and harmful chemical agent for the eyes, skin and lungs that causes short-term and long-term lesions and was widely used in Iraq war against Iran (1980-1988). SM causes DNA damages, oxidative stress, and Inflammation. Considering the similarities between SM and COPD (Chronic Obstructive Pulmonary Disease) pathogens and limited available treatments, a novel therapeutic approach is not developed. Gene therapy is a novel therapeutic approach that uses genetic engineering science in treatment of most diseases including chronic obstructive pulmonary disease. In this review, attempts to presenting a comprehensive study of mustard lung and introducing the genes therapy involved in chronic obstructive pulmonary disease and emphasizing the pathways and genes involved in the pathology and pathogenesis of sulfur Mustard. It seems that, given the high potential of gene therapy and the fact that this experimental technique is a candidate for the treatment of pulmonary diseases, further study of genes, vectors and gene transfer systems can draw a very positive perspective of gene therapy in near future.

Dietary ω-6 polyunsaturated fatty acid arachidonic acid increases inflammation, but inhibits ECM protein expression in COPD

Background

The obesity paradox in COPD describes protective effects of obesity on lung pathology and inflammation. However, the underlying relationships between obesity, diet and disease outcomes in COPD are not fully understood. In this study we measured the response to dietary fatty acids upon markers of inflammation and remodelling in human lung cells from people with and without COPD.

Methods

Pulmonary fibroblasts were challenged with ω-3 polyunsaturated fatty acids (PUFAs), ω-6 PUFAs, saturated fatty acids (SFAs) or the obesity-associated cytokine TNFα. After 48–72 h release of the pro-inflammatory cytokines interleukin (IL)-6 and CXCL8 was measured using ELISA and mRNA expression and deposition of the extracellular matrix (ECM) proteins fibronectin, type I collagen, tenascin and perlecan were measured using qPCR or ECM ELISA, respectively.

Results

Challenge with the ω-6 PUFA arachidonic acid (AA), but not ω-3 PUFAs or SFAs, resulted in increased IL-6 and CXCL8 release from fibroblasts, however IL-6 and CXCL8 release was reduced in COPD (n = 19) compared to non-COPD (n = 36). AA-induced cytokine release was partially mediated by downstream mediators of cyclooxygenase (COX)-2 in both COPD and non-COPD. In comparison, TNFα-induced IL-6 and CXCL8 release was similar in COPD and non-COPD, indicating a specific interaction of AA in COPD. In patients with or without COPD, regression analysis revealed no relationship between BMI and cytokine release. In addition, AA, but not SFAs or ω-3 PUFAs reduced the basal deposition of fibronectin, type I collagen, tenascin and perlecan into the ECM in COPD fibroblasts. In non-COPD fibroblasts, AA-challenge decreased basal deposition of type I collagen and perlecan, but not fibronectin and tenascin.

Conclusions

This study shows that AA has disease-specific effects on inflammation and ECM protein deposition. The impaired response to AA in COPD might in part explain why obesity appears to have less detrimental effects in COPD, compared to other lung diseases.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0919-4) contains supplementary material, which is available to authorized users.

Cigarette smoke and non-neuronal cholinergic system in the airway epithelium of COPD patients

Acetylcholine (ACh), synthesized by Choline Acetyl-Transferase (ChAT), exerts its physiological effects via mAChRM3 in epithelial cells. We hypothesized that cigarette smoke affects ChAT, ACh, and mAChRM3 expression in the airways from COPD patients promoting airway disease. ChAT, ACh, and mAChRM3 were assessed: "ex vivo" in the epithelium from central and distal airways of COPD patients, Healthy Smoker (S) and Healthy Subjects (C), and "in vitro" in bronchial epithelial cells stimulated with cigarette smoke extract (CSE). In central airways, mAChRM3, ChAT, and ACh immunoreactivity was significantly higher in the epithelium from S and COPD than in C subjects. mAChRM3, ChAT, and ACh score of immunoreactivity was high in the metaplastia area of COPD patients. mAChRM3/ChAT and ACh/ChAT co-localization of immunoreactivity was observed in the bronchial epithelium from COPD. In vitro, CSE stimulation significantly increased mAChRM3, ChAT, and ACh expression and mAChRM3/ChAT and ACh/ChAT co-localization in 16HBE and NHBE, and increased 16HBE proliferation. Cigarette smoke modifies the levels of mAChMR3, ChAT expression, and ACh production in bronchial epithelial cells from COPD patients. Non-neuronal components of cholinergic system may have a role in the mechanism of bronchial epithelial cell proliferation, promoting alteration of normal tissue, and of related pulmonary functions.

Role of the Lung Microbiome in the Pathogenesis of Chronic Obstructive Pulmonary Disease

OBJECTIVE

The development of culture-independent techniques for microbiological analysis shows that bronchial tree is not sterile in either healthy or chronic obstructive pulmonary disease (COPD) individuals. With the advance of sequencing technologies, lung microbiome has become a new frontier for pulmonary disease research, and such advance has led to better understanding of the lung microbiome in COPD. This review aimed to summarize the recent advances in lung microbiome, its relationships with COPD, and the possible mechanisms that microbiome contributed to COPD pathogenesis.

DATA SOURCES

Literature search was conducted using PubMed to collect all available studies concerning lung microbiome in COPD. The search terms were "microbiome" and "chronic obstructive pulmonary disease", or "microbiome" and "lung/pulmonary".

STUDY SELECTION

The papers in English about lung microbiome or lung microbiome in COPD were selected, and the type of articles was not limited.

RESULTS

The lung is a complex microbial ecosystem; the microbiome in lung is a collection of viable and nonviable microbiota (bacteria, viruses, and fungi) residing in the bronchial tree and parenchymal tissues, which is important for health. The following types of respiratory samples are often used to detect the lung microbiome: sputum, bronchial aspirate, bronchoalveolar lavage, and bronchial mucosa. Disordered bacterial microbiome is participated in pathogenesis of COPD; there are also dynamic changes in microbiota during COPD exacerbations. Lung microbiome may contribute to the pathogenesis of COPD by manipulating inflammatory and/or immune process.

CONCLUSIONS

Normal lung microbiome could be useful for prophylactic or therapeutic management in COPD, and the changes of lung microbiome could also serve as biomarkers for the evaluation of COPD.

Ethyl rosmarinate inhibits lipopolysaccharide-induced nitric oxide and prostaglandin E2 production in alveolar macrophages

In this study, a series of rosmarinic acid and analogs were investigated for their anti-inflammatory potential against LPS-induced alveolar macrophages (MH-S). Our results showed that, among the test compounds, ethyl rosmarinate (3) exhibited the most potent inhibitory effect on NO production in LPS-induced MH-S cells, with low cytotoxicity. Compound 3 exhibited remarkable inhibition of the production of PGE2 in LPS-induced MH-S cells. The inhibitory potency of compound 3 against LPS-induced NO and PGE2 release was approximately two-fold higher than that of dexamethasone. Compound 3 significantly decreased the mRNA and protein expression of iNOS and COX-2 and suppressed p65 expression in the nucleus in LPS-induced MH-S cells. These results suggested that compound 3 inhibited NO and PGE2 production, at least in part, through the down-regulation of NF-κB activation. Analysis of structure-activity relationship revealed that the free carboxylic group did not contribute to inhibitory activity and that the alkyl group of the corresponding alkyl ester analogs produced a strong inhibitory effect. We concluded that compound 3, a structurally modified rosmarinic acid, possessed potent inhibitory activity against lung inflammation, which strongly supported the development of this compound as a novel therapeutic agent for the treatment of macrophage-mediated lung inflammatory diseases, such as COPD.

MAPK/FoxA2-mediated cigarette smoke-induced squamous metaplasia of bronchial epithelial cells

Objective

To explore the effect of cigarette smoke (CS) on the development of squamous metaplasia in human airway epithelial cells and the role of MAPK- and FoxA2-signaling pathways in the process.

Materials and methods

In an in vitro study, we treated the bronchial epithelial cell line BEAS2B with CS extract, followed by treatment with the ERK inhibitor U0126, the JNK inhibitor SP600125, or the p38 inhibitor SB203580. In vivo, we used a CS-induced rat model. After treatment with CS with or without MAPK inhibitors for 90 days, lung tissues were harvested. p-ERK, p-p38 and p-JNK protein levels in cells and lung tissue were measured using enzyme-linked immunosorbent assays, mRNA- and protein-expression profiles of FoxA2, E-cadherin, CD44, and ZO1 were measured using quantitative real-time polymerase chain reaction and Western blotting, respectively, and morphological changes in bronchial epithelial cells were observed using lung-tissue staining.

Results

In both the in vitro and in vivo studies, phosphorylation of the ERK1/2, JNK, and p38 proteins was significantly increased (P<0.05) and mRNA and protein expression of E-cadherin and FoxA2 significantly decreased (P<0.05) compared with the control group. ERK, JNK, and p38 inhibitors reversed the CS-extract-induced changes in E-cadherin, CD44, and ZO1 mRNA and protein expression (P<0.05), decreased p-ERK, p-p38, and p-JNK protein levels in cells and lung tissue, suppressed bronchial epithelial hyperplasia and local squamous metaplasia, and decreased FoxA2 expression.

Conclusion

MAPK and FoxA2 mediate CS-induced squamous metaplasia. MAPK inhibitors upregulate FoxA2, resulting in a reduction in the degree of squamous metaplasia.

Macrophages: Their role, activation and polarization in pulmonary diseases

Macrophages, circulating in the blood or concatenated into different organs and tissues constitute the first barrier against any disease. They are foremost controllers of both innate and acquired immunity, healthy tissue homeostasis, vasculogenesis and congenital metabolism. Two hallmarks of macrophages are diversity and plasticity due to which they acquire a wobbling array of phenotypes. These phenotypes are appropriately synchronized responses to a variety of different stimuli from either the tissue microenvironment or - microbes or their products. Based on the phenotype, macrophages are classified into classically activated/(M1) and alternatively activated/(M2) which are further sub-categorized into M2a, M2b, M2c and M2d based upon gene expression profiles. Macrophage phenotype metamorphosis is the regulating factor in initiation, progression, and termination of numerous inflammatory diseases. Several transcriptional factors and other factors controlling gene expression such as miRNAs contribute to the transformation of macrophages at different points in different diseases. Understanding the mechanisms of macrophage polarization and modulation of their phenotypes to adjust to the micro environmental conditions might provide us a great prospective for designing novel therapeutic strategy. In view of the above, this review summarises the activation of macrophages, the factors intricated in activation along with benefaction of macrophage polarization in response to microbial infections, pulmonary toxicity, lung injury and other inflammatory diseases such as chronic obstructive pulmonary dysplasia (COPD), bronchopulmonary dysplasia (BPD), asthma and sepsis, along with the existing efforts to develop therapies targeting this facet of macrophage biology.

Local delivery of siRNA-loaded calcium phosphate nanoparticles abates pulmonary inflammation

The local interference of cytokine signaling mediated by siRNA-loaded nanoparticles might be a promising new therapeutic approach to dampen inflammation during pulmonary diseases. For the local therapeutic treatment of pulmonary inflammation, we produced multi-shell nanoparticles consisting of a calcium phosphate core, coated with siRNAs directed against pro-inflammatory mediators, encapsulated into poly(lactic-co-glycolic acid), and coated with a final outer layer of polyethylenimine. Nasal instillation of nanoparticles loaded with a mixture of siRNAs directed against different cytokines to mice suffering from T_H1 cell-mediated lung inflammation, or of siRNA directed against NS-1 in an influenza infection model led to a significant reduction of target gene expression which was accompanied by distinct amelioration of lung inflammation in both models. Thus, this study provides strong evidence that the specific and local modulation of the inflammatory response by CaP/PLGA nanoparticle-mediated siRNA delivery could be a promising approach for the treatment of inflammatory disorders of the lung.

Inhalation of progesterone inhibits chronic airway inflammation of mice exposed to ozone

Chronic ozone exposure leads to a model of mice with lung inflammation, emphysema and oxidative stress. Progesterone plays an important role in attenuating the neuroinflammation. We assume that progesterone will reduce the chronic airway inflammation exposed to ozone and evaluate whether combination of progesterone with glucocorticoids results in synergistic effects. C57/BL6 mice were exposed to ozone (2.5ppm, 3h) 12 times over 6 weeks, and were administered with progesterone (0.03 or 0.3mg/L; inhaled) alone or combined with budesonide (BUD) (0.2g/L) after each exposure until the tenth week. Mice were studied 24h after final exposure, cells and inflammatory mediators were assessed in bronchoalveolar lavage fluid (BALF) and lungs used for evaluation of glucocorticoids receptors (GR), p38 mitogen-activated protein kinase (MAPK) phosphorylation and nuclear transcription factor κB (NF-κB) activation. Exposure to ozone resulted in a marked lung neutrophilia. Moreover, in ozone-exposed group, the levels of oxidative stress-related interleukin (IL)-1β, IL-6, IL-8, IL-17A, activated NF-κB and p38MAPK, airway inflammatory cells infiltration density, mean linear intercept (Lm) were greatly increased, FEV₂₅ and glucocorticoids receptors (GR) were markedly decreased. Comparable to BUD, progesterone treatment dose-dependently led to a significant reduction of IL-1β, IL-6, IL-8, IL-17A, activated NF-κB and p38MAPK, and an increase of FEV₂₅ and GR. Progesterone combined with BUD resulted in dramatic changes, compared to monotherapy of BUD or progesterone. Therefore, these results demonstrate that chronic ozone exposure has profound airway inflammatory effects counteracted by progesterone and progesterone acts synergistically with glucocorticoids in attenuating the airway inflammation dose-dependently.

Liujunzi Tang, a famous traditional Chinese medicine, ameliorates cigarette smoke-induced mouse model of COPD

ETHNOPHARMACOLOGICAL RELEVANCE

Liujunzi Tang is a traditional herbal medicine widely used in East Asia and clinically applied to treat Phlegm-Heat Syndrome. The purpose of the present study was to investigate the protective effects of Liujunzi Tang on cigarette smoke-induced (CS) mouse model of chronic obstructive pulmonary disease (COPD) and explore its potential molecular mechanism.

MATERIALS AND METHODS

The mice received 1h of cigarette smoke for 8 weeks. The serum levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were determined by enzyme-linked immunosorbent assay (ELISA) kits. Superoxide dismutase (SOD) and malondialdehyde (MDA) were tested by biochemical methods. Histopathological alteration was observed by hematoxylin-eosin (H&E) staining. Additionally, the expressions of nuclear transcription factor-κB (NF-κBp65) and (inhibitor of NF-κB)IκB-α were determined by western blot and immunohistochemistry analysis.

RESULTS

Liujunzi Tang enhanced the activities of antioxidant enzymes and attenuated the levels of lipid oxidative production, meanwhile significantly inhibited the generations of inflammatory cytokines by inhibiting the phosphorylation of IκB-α and NF-κB.

CONCLUSION

Our findings indicated that Liujunzi Tang exhibited the protective effect on cigarette smoke-induced COPD mice by anti-inflammatory and anti-oxidative properties through the inhibition of NF-κB activation.

Genetic Polymorphism of Angiotensin-Converting Enzyme and Chronic Obstructive Pulmonary Disease Risk: An Updated Meta-Analysis

The relationship between polymorphism of the angiotensin I converting enzyme (ACE) gene and chronic obstructive pulmonary disease (COPD) has been examined in many previous studies. However, their results were controversial. Therefore, we performed a meta-analysis to evaluate the relationship between the ACE gene and the risk of COPD. Fourteen case-control studies were included in this meta-analysis. The pooled p value, odds ratio (OR), and 95% confidence interval (95% CI) were used to investigate the strength of the association. The meta-analysis was performed using comprehensive meta-analysis software. Our meta-analysis results revealed that ACE polymorphisms were not related to the risk of COPD (p > 0.05 in each model). In further analyses based on ethnicity, we observed an association between insertion/deletion polymorphism of the ACE gene and risk of COPD in the Asian population (codominant 2, OR = 3.126, 95% CI = 1.919–5.093, p < 0.001; recessive, OR = 3.326, 95% CI = 2.190–5.050, p < 0.001) but not in the Caucasian population (p > 0.05 in each model). In conclusion, the present meta-analysis indicated that the insertion/deletion polymorphism of the ACE gene may be associated with susceptibility to COPD in the Asian population but not in the Caucasian population. However, the results of the present meta-analysis need to be confirmed in a larger sample.

Exosomes and Exosomal miRNA in Respiratory Diseases

Exosomes are nanosized vesicles released from every cell in the body including those in the respiratory tract and lungs. They are found in most body fluids and contain a number of different biomolecules including proteins, lipids, and both mRNA and noncoding RNAs. Since they can release their contents, particularly miRNAs, to both neighboring and distal cells, they are considered important in cell-cell communication. Recent evidence has shown their possible importance in the pathogenesis of several pulmonary diseases. The differential expression of exosomes and of exosomal miRNAs in disease has driven their promise as biomarkers of disease enabling noninvasive clinical diagnosis in addition to their use as therapeutic tools. In this review, we summarize recent advances in this area as applicable to pulmonary diseases.

[Morphometric characteristics of the bronchial tree in smokers with and without chronic obstructive pulmonary disease]

AIM

To reveal the tissue, cellular, and molecular predictors leading to the development of chronic obstructive pulmonary disease (COPD) in smokers on the basis of a morphometric analysis of bronchial biopsy specimens.

MATERIALS AND METHODS

A cross-sectional study was conducted in 115 smokers aged 40 to 60 years (58.3±3.24 years) with a male predominance of 90.9%. Morphological examination of bronchial biopsy specimens was first made in the smoking patients with and without COPD.

RESULTS

The smokers with COPD versus those without this condition were found to have a statistically significant increase in a number of indicators: the specific volume (SV) of the surface epithelium (p=0.017), SV of basal epitheliocytes (p=0.008), the height of the epithelium (p=0.001), and the thickness of the basal membrane (p=0.006) due to impaired regeneration processes in the bronchial epithelium and to fibrosis of the lamina propria of the bronchi with a concurrent increase in the total number of fibroblasts. The group of smokers with COPD, unlike the comparison group, showed signs of vascular remodeling and microcirculatory disorders as the increased connective tissue volumetric density of the lamina propria of the bronchi with predominant perivascular localization. This was followed by reductions in the relative volume of capillaries (p=0.016), in the SV of micropinocytic vesicles (p=0.005), and the size of Weibel-Palade bodies (p=0.004) in the endotheliocytes. In the COPD patients, the total density of cell infiltrate per mm2 of the lamina propria of the bronchi was statistically significantly (p<0.001) greater than that in the comparison group at the expense of neutrophils, lowly and moderately granulated basophils, macrophages, plasma cells with a simultaneous rise in their interepithelial forms.

CONCLUSION

Compensatory structural changes without signs of bronchial wall remodeling were recorded in the smokers without signs of bronchial disease. The smokers with the examined nosological entity were observed to have morphological signs of hemodynamic disorders, as well as perivascular fibrosis, atrophy, and squamous cell metaplasia of the bronchial epithelial lining.

Bacterial-viral load and the immune response in stable and exacerbated COPD: significance and therapeutic prospects

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and an abnormal inflammatory response of the lung. Bacteria and viruses are a major cause of COPD exacerbations and may contribute to COPD progression by perpetuating the inflammatory response in the airways. Bacterial variety diminishes with increasing COPD severity. Respiratory viruses can colonize the lower respiratory tract in stable COPD, altering the respiratory microbiome and facilitating secondary bacterial infections. In this review, we present the most updated information about the role of bacteria and viruses in stable and exacerbated COPD. In our opinion, to optimize therapeutic strategies, the dynamic events involving bacterial-viral infections and related immune response in COPD phenotypes need to be better clarified. Our paper would address these points that we consider of great importance for the clinical management of COPD.

Apocynin and ebselen reduce influenza A virus-induced lung inflammation in cigarette smoke-exposed mice

Influenza A virus (IAV) infections are a common cause of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Oxidative stress is increased in COPD, IAV-induced lung inflammation and AECOPD. Therefore, we investigated whether targeting oxidative stress with the Nox2 oxidase inhibitors and ROS scavengers, apocynin and ebselen could ameliorate lung inflammation in a mouse model of AECOPD. Male BALB/c mice were exposed to cigarette smoke (CS) generated from 9 cigarettes per day for 4 days. On day 5, mice were infected with 1 × 10(4.5) PFUs of the IAV Mem71 (H3N1). BALF inflammation, viral titers, superoxide production and whole lung cytokine, chemokine and protease mRNA expression were assessed 3 and 7 days post infection. IAV infection resulted in a greater increase in BALF inflammation in mice that had been exposed to CS compared to non-smoking mice. This increase in BALF inflammation in CS-exposed mice caused by IAV infection was associated with elevated gene expression of pro-inflammatory cytokines, chemokines and proteases, compared to CS alone mice. Apocynin and ebselen significantly reduced the exacerbated BALF inflammation and pro-inflammatory cytokine, chemokine and protease expression caused by IAV infection in CS mice. Targeting oxidative stress using apocynin and ebselen reduces IAV-induced lung inflammation in CS-exposed mice and may be therapeutically exploited to alleviate AECOPD.

The Impact of Exogenous Factors on Respiratory Pathogen-Induced Innate Alveolar Macrophage Responses in COPD

Alveolar macrophages in chronic obstructive pulmonary disease (COPD) have fundamentally impaired innate immune responses to toll-like receptor (TLR) ligands of nontypeable Haemophilus influenzae (NTHI). However, whether dysfunctional inflammatory responses in COPD extend to macrophage interactions with intact respiratory pathogens beyond NTHI has not been explored. Furthermore, the influences of exogenous factors, including active smoking and medications, on pathogen-induced innate immune responses have only begun to be investigated. We hypothesized that distinct alveolar macrophage impairments in COPD are not limited to NTHI TLR ligands and that active smoking and select COPD medications modulate innate responses. Alveolar macrophages, obtained from COPD ex-smokers (n = 32) and active smokers (n = 64) by bronchoalveolar lavage (BAL), were incubated with NTHI, Moraxella catarrhalis, and Streptococcus pneumoniae, and with TLR2 and TLR4 ligands. Elicited IL-8 and TNF-α were measured by multianalyte microsphere flow cytometry to determine proinflammatory responsiveness. Induced IL-8, but not TNF-α, was greater from alveolar macrophages of active smokers compared with ex-smokers, in response to NTHI (p = 0.04), M. catarrhalis (p = 0.003), and S. pneumoniae (p = 0.03). Both IL-8 and TNF-α induction by TLR2 and TLR4 ligands were greater in active smokers. While intergroup NTHI- and M. catarrhalis-induced TNF-α levels were no different, they were notably lower among ex-smokers taking anticholinergic medications (p < 0.04 for each), but not with any other bronchoactive medications. Our results support a paradigm of distinct immunologic responses of COPD alveolar macrophages of ex- and active smokers to diverse respiratory pathogens and highlight a subset of ex-smokers whose diminished alveolar macrophage responsiveness may be associated with anticholinergic agents.

The MIF Antagonist ISO-1 Attenuates Corticosteroid-Insensitive Inflammation and Airways Hyperresponsiveness in an Ozone-Induced Model of COPD

Introduction

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine associated with acute and chronic inflammatory disorders and corticosteroid insensitivity. Its expression in the airways of patients with chronic obstructive pulmonary disease (COPD), a relatively steroid insensitive inflammatory disease is unclear, however.

Methods

Sputum, bronchoalveolar lavage (BAL) macrophages and serum were obtained from non-smokers, smokers and COPD patients. To mimic oxidative stress-induced COPD, mice were exposed to ozone for six-weeks and treated with ISO-1, a MIF inhibitor, and/or dexamethasone before each exposure. BAL fluid and lung tissue were collected after the final exposure. Airway hyperresponsiveness (AHR) and lung function were measured using whole body plethysmography. HIF-1α binding to the Mif promoter was determined by Chromatin Immunoprecipitation assays.

Results

MIF levels in sputum and BAL macrophages from COPD patients were higher than those from non-smokers, with healthy smokers having intermediate levels. MIF expression correlated with that of HIF-1α in all patients groups and in ozone-exposed mice. BAL cell counts, cytokine mRNA and protein expression in lungs and BAL, including MIF, were elevated in ozone-exposed mice and had increased AHR. Dexamethasone had no effect on these parameters in the mouse but ISO-1 attenuated cell recruitment, cytokine release and AHR.

Conclusion

MIF and HIF-1α levels are elevated in COPD BAL macrophages and inhibition of MIF function blocks corticosteroid-insensitive lung inflammation and AHR. Inhibition of MIF may provide a novel anti-inflammatory approach in COPD.

The Role of Innate and Adaptive Immune Cells in the Immunopathogenesis of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a chronic and progressive inflammatory disease of the airways and lungs that results in limitations of continuous airflow and is caused by exposure to noxious gasses and particles. A major cause of morbidity and mortality in adults, COPD is a complex disease pathologically mediated by many inflammatory pathways. Macrophages, neutrophils, dendritic cells, and CD8+ T-lymphocytes are the key inflammatory cells involved in COPD. Recently, the non-coding small RNA, micro-RNA, have also been intensively investigated and evidence suggest that it plays a role in the pathogenesis of COPD. Here, we discuss the accumulated evidence that has since revealed the role of each inflammatory cell and their involvement in the immunopathogenesis of COPD. Mechanisms of steroid resistance in COPD will also be briefly discussed.

Cigarette smoke affects IL-17A, IL-17F and IL-17 receptor expression in the lung tissue: Ex vivo and in vitro studies

Cigarette smoke is a risk factor for Chronic Obstructive Pulmonary Disease (COPD). Th-17 cytokines are involved in the pathogenesis of COPD. We aimed to evaluate the role of cigarette smoke on the expression of IL-17A, IL-17F and IL-17R in airways of COPD patients. Epithelial and subepithelial immunoreactivity for IL-17A, IL-17F and IL-17R was assessed in surgical specimens from COPD patients (n=15) and from healthy subjects (HC) (n=10) by immunohistochemistry. In vitro, human epithelial cell line 16HBE and A549 as well as PBMC from normal donors were stimulated with cigarette smoke extract (CSE) (0%, 2.5%, 5%, 10%) to evaluate the IL-17A, IL-17F and IL-17R expression by flow cytometry. Furthermore, rhIL-17A and CSE stimulation was evaluated on proliferation and apoptosis in 16HBE and in A549. In central and distal airways immunoreactivity for IL-17A, IL-17F and IL-17R significantly increased in the epithelium and IL-17A in the subepithelium from COPD than in HC. In distal airway, immunoreactivity for IL-17F increased in the subepithelium of COPD than in HC. IL-17A immunoreactivity positively correlate with IL-17R and total pack years in the epithelium from central and distal airways of COPD patients. In vitro, CSE stimulation significantly increased IL-17F and IL-17R in 16HBE (2.5%) and A549 (5%) while IL-17A and IL-17F in PBMC (10%). IL-17A and CSE stimulation, rather than CSE or rhIL-17A alone, significantly increased proliferation in 16HBE and apoptosis in A549. Cigarette smoke increases Th17 immunity in lung tissue of COPD patients, promoting the mechanism of proliferation and apoptosis in airway epithelial cells.

Correlation of Cigarette Smoke-Induced Pulmonary Inflammation and Emphysema in C3H and C57Bl/6 Mice

Cigarette smoke (CS)-exposed mice have been used to model airway inflammation and emphesema in humans; however, the impact of exposure duration, sex, and strain differences in susceptibility to progression of airway inflammation and to emphesema are poorly investigated. This study was designed to determine the association between inflammation and emphysema by exposing 2 strains of mice, C3H/HeN (C3H) and C57BL/6 (Bl/6), to filtered air (FA) or CS for 10, 16, or 22 weeks. Both genders and strains of CS-exposed mice developed pulmonary inflammation as characterized by cell counts in the bronchoalveolar lavage fluid (BALF) and the levels of matrix metalloproteinases (MMPs) in the BALF. CS exposure caused persistently higher number of BALF macrophages in C3H compared to BL/6 mice, while more BALF neutrophils and persistently higher MMP-2 and MMP-9 levels were observed in BL/6 mice. The mean linear intercept (Lm) increased progressively by 26%, 33%, and 55% at 10, 16, and 22 weeks, respectively, in CS-exposed C3H mice compared to the matched air controls. In BL/6 mice, although CS exposure also increased the Lm compared to FA controls, no further increase in Lm beyond the levels observed at 16 weeks of exposure was observed by 22 weeks. These findings suggest that extent of inflammation is not associated with severity of emphysema and underscores the importance of carefully selecting the mouse strains and endpoints when exploring effective treatments for emphesema.

CXCR2 Antagonist MK-7123. A Phase 2 Proof-of-Concept Trial for Chronic Obstructive Pulmonary Disease

RATIONALE

An antagonist (MK-7123) of the cytokine receptor CXCR2 reduces neutrophil chemotaxis and thus may alleviate airway inflammation in chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To assess the efficacy, safety, and tolerability of three dose levels of MK-7123, compared with placebo, in patients with moderate to severe COPD.

METHODS

This 6-month, double-blind study randomized patients with moderate to severe COPD (already on standard therapy) to daily MK-7123 at 10, 30, or 50 mg or placebo. The primary endpoint was change from baseline in post-bronchodilator FEV1.

MEASUREMENTS AND MAIN RESULTS

A total of 616 patients (71% male; mean age, 63 yr; 45% current smokers; baseline FEV1 [SD], 1.43 L [0.45]; mean FEV1 percent predicted, 43.9%) were randomized. Only MK-7123 50 mg led to significant improvement in FEV1 over placebo (mean difference [SE], 67 ml [32]). Reduced sputum neutrophil count was observed among the 122 patients examined; P = 0.003 (3 mo) and P = 0.092 (6 mo) (MK-7123 50 mg vs. placebo). The stratum of current smokers, but not that of nonsmokers, showed significant improvement versus placebo in FEV1 (168 ml) and time-to-first exacerbation, and showed numerical improvement in St. George's Respiratory Questionnaire for COPD score. MK-7123 caused a dose-dependent decrease in absolute neutrophil count (ANC) and reduced inflammatory biomarkers matrix metallopeptidase-9 and myeloperoxidase in plasma and sputum; ANC lower than 1.5 × 10(9)/L led to discontinuations with higher doses of MK-7123 (18% in the MK-7123 50-mg group vs. 1% in placebo). Plasma C-reactive protein and fibrinogen increased with MK-7123 treatment. Rates of infections at 6 months were similar in all groups.

CONCLUSIONS

Treatment with MK-7123 50 mg versus placebo led to significant improvement in FEV1 in patients with COPD, suggesting clinically important antiinflammatory effects with CXCR2 antagonism, although dose-related discontinuations were observed because of ANC decreases with MK-7123. Greater response was observed in smokers versus ex-smokers. Clinical trial registered with www.clinicaltrials.gov (NCT 01006616).

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

BACKGROUND

The role of mitogen-activated protein kinases (MAPK) in regulating the inflammatory response in the airways of patients with chronic obstructive pulmonary disease (COPD) and asthmatic patients is unclear.

OBJECTIVES

To investigate the expression of activated MAPK in lungs of COPD patients and in bronchial biopsies of asthmatic patients and to study MAPK expression in bronchial epithelial cells in response to oxidative and inflammatory stimuli.

METHODS

Immunohistochemical expression of phospho (p)-p38 MAPK, p-JNK1 and p-ERK1/2 was measured in bronchial mucosa in patients with mild/moderate (n = 17), severe/very severe (n = 16) stable COPD, control smokers (n = 16), control non-smokers (n = 9), in mild asthma (n = 9) and in peripheral airways from COPD patients (n = 15) and control smokers (n = 15). Interleukin (IL)-8 and MAPK mRNA was measured in stimulated 16HBE cells.

RESULTS

No significant differences in p-p38 MAPK, p-JNK or p-ERK1/2 expression were seen in bronchial biopsies and peripheral airways between COPD and control subjects. Asthmatics showed increased submucosal p-p38 MAPK expression compared to COPD patients (p < 0.003) and control non-smokers (p < 0.05). Hydrogen peroxide (H₂O₂), cytomix (tumour necrosis factor-α + IL-1β + interferon-γ) and lipopolysaccharide (LPS) upregulated IL-8 mRNA at 1 or 2 h. p38 MAPKα mRNA was significantly increased after H₂O₂ and LPS treatment. JNK1 and ERK1 mRNA were unchanged after H₂O₂, cytomix or LPS treatments.

CONCLUSION

p-p38 MAPK expression is similar in stable COPD and control subjects but increased in the bronchi of mild asthmatics compared to stable COPD patients. p38 MAPK mRNA is increased after bronchial epithelial challenges in vitro. These data together suggest a potential role for this MAPK in Th2 inflammation and possibly during COPD exacerbations.

Molecular pathogenesis of cigarette smoking-induced stable COPD

Inflammation is a central feature of stable chronic obstructive pulmonary disease (COPD) and involves both activation of structural cells of the airways and the lungs and the activation and/or recruitment of infiltrating inflammatory cells. This results in enhanced expression of many pro-inflammatory proteins and reduced expression of some anti-inflammatory mediators. An altered protein expression is generally associated with concomitant changes in gene expression profiles in a cell-specific manner. Increased understanding of the role of transcription factors and of the signaling pathways leading to their activation in stable COPD will provide new targets to enable the development of potential anti-inflammatory drugs. Several new compounds targeting these pathways and/or transcription factors are now in development for the treatment of stable COPD. Furthermore, glucocorticoids drugs already in clinical use act through their own transcription factor, the glucocorticoid receptor, to control the expression of inflammatory and anti-inflammatory genes.

Effect of Quanzhenyiqitang on apoptosis of alveolar macrophages and expression of histone deacetylase 2 in rats with chronic obstructive pulmonary disease

This study aimed to investigate the effect of Quanzhenyiqitang on alveolar macrophages (AMs) in a rat model of chronic obstructive pulmonary disease (COPD). In addition, the induction of apoptosis and regulation of histone deacetylase 2 (HDAC2) was studied to elucidate the underlying mechanisms of Quanzhenyiqitang treatment of COPD. Quanzhenyiqitang-treated serum was applied to AMs obtained from rats with COPD. A blank (control) group, an untreated serum group and an aminophylline group were also observed to evaluate the differences in AM apoptosis status, as well as the expression levels of caspase-9, caspase-8 and HDAC2. Compared with the control group, Quanzhenyiqitang-treated serum resulted in higher levels of caspase-9 and caspase-8 expression, increased apoptosis of AMs and increased expression of HDAC2 by AMs. In conclusion, Quanzhenyiqitang is capable of inducing apoptosis of AMs, which are the primary inflammatory cells in COPD, and modulating the expression of the important inflammatory factor HDAC2, producing an overall anti-inflammatory effect.