Circulating monocytes from healthy individuals and COPD patients

Characterization of IL-6R-expressing monocytes in the lung of patients with chronic obstructive pulmonary disease

BACKGROUND

Monocytes play a crucial role in innate immune responses for host defense, however, their involvement in chronic obstructive pulmonary disease (COPD) remains poorly understood. We previously identified a subset of monocytes in COPD lung tissues characterized by high interleukin-6 receptor (IL-6R) expression. This study aimed to characterize the phenotypes of IL-6Rhi monocytes in the lungs of COPD patients.

METHODS

Using flow cytometry, we assessed the abundance of pulmonary CD14+IL-6Rhi cells in never smokers (CNS), control ex-smokers (CES) and COPD patients. IL-6 expression in CD14+ monocytes isolated from the peripheral blood of patients with COPD was also examined. CD45+CD206-CD14+IL-6Rhi and CD45+CD206-CD14+IL-6R-/lo cells were isolated from COPD lung tissues for transcriptome analysis. A monocyte line THP1 cell with constitutive IL-6R expression was stimulated with recombinant IL-6, followed by RNA sequencing to evaluate the IL-6 responsiveness of IL-6R+ monocytes.

RESULTS

The number of pulmonary CD14+IL-6Rhi monocytes was elevated in COPD patients compared to CNS, whereas CD14+ monocytes in the peripheral blood of COPD patients did not express IL-6R. Upregulated mRNA expression in CD14+IL-6Rhi monocytes was associated with chemotaxis, monocyte differentiation, fatty acid metabolism and integrin-mediated signaling pathway. Stimulation of THP1 cells with recombinant IL-6 induced changes in the expression of genes linked to chemotaxis and organism development.

CONCLUSION

In patients with COPD, CD14+IL-6Rhi monocytes are increased in lung tissues compared to those in CNS. They exhibit a transcriptome profile different from that of CD14+IL-6R-/lo monocytes.

Cell-Free DNA Maps Tissue Injury and Correlates with Disease Severity in Lung Transplant Candidates

Rationale: Plasma cell-free DNA levels correlate with disease severity in many conditions. Pretransplant cell-free DNA may risk stratify lung transplant candidates for post-transplant complications. Objectives: To evaluate if pretransplant cell-free DNA levels and tissue sources identify patients at high risk of primary graft dysfunction and other pre- and post-transplant outcomes. Methods: This multicenter, prospective cohort study recruited 186 lung transplant candidates. Pretransplant plasma samples were collected to measure cell-free DNA. Bisulfite sequencing was performed to identify the tissue sources of cell-free DNA. Multivariable regression models determined the association between cell-free DNA levels and the primary outcome of primary graft dysfunction and other transplant outcomes, including Lung Allocation Score, chronic lung allograft dysfunction, and death. Measurements and Main Results: Transplant candidates had twofold greater cell-free DNA levels than healthy control patients (median [interquartile range], 23.7 ng/ml [15.1-35.6] vs. 12.9 ng/ml [9.9-18.4]; P < 0.0001), primarily originating from inflammatory innate immune cells. Cell-free DNA levels and tissue sources differed by native lung disease category and correlated with the Lung Allocation Score (P < 0.001). High pretransplant cell-free DNA increased the risk of primary graft dysfunction (odds ratio, 1.60; 95% confidence interval [CI], 1.09-2.46; P = 0.0220), and death (hazard ratio, 1.43; 95% CI, 1.07-1.92; P = 0.0171) but not chronic lung allograft dysfunction (hazard ratio, 1.37; 95% CI, 0.97-1.94; P = 0.0767). Conclusions: Lung transplant candidates demonstrate a heightened degree of tissue injury with elevated cell-free DNA, primarily originating from innate immune cells. Pretransplant plasma cell-free DNA levels predict post-transplant complications.

Identification and Characterization of a ceRNA Regulatory Network Involving LINC00482 and PRRC2B in Peripheral Blood Mononuclear Cells: Implications for COPD Pathogenesis and Diagnosis

Purpose

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, characterized by intense lung infiltrations of immune cells (macrophages and monocytes). While existing studies have highlighted the crucial role of the competitive endogenous RNA (ceRNA) regulatory network in COPD development, the complexity and characteristics of the ceRNA network in monocytes remain unexplored.

Methods

We downloaded messenger RNA (mRNA), microRNA (miRNA), and long noncoding RNA (lncRNA) microarray data from GSE146560, GSE102915, and GSE71220 in the Gene Expression Omnibus (GEO) database. This data was used to identify differentially expressed mRNAs (DEmRNAs), miRNAs (DEmiRNAs), and lncRNAs (DElncRNAs). Predicted miRNAs that bind to DElncRNAs were intersected with DEmiRNAs, forming a set of intersecting miRNAs. This set was then used to predict potential binding mRNAs, intersected with DEmRNAs, and underwent functional enrichment analysis using R software and the STRING database. The resulting triple regulatory network and hub genes were constructed using Cytoscape. Comparative Toxicomics Database (CTD) was utilized for disease correlation predictions, and ROC curve analysis assessed diagnostic accuracy.

Results

Our study identified 5 lncRNAs, 4 miRNAs, and 149 mRNAs as differentially expressed. A lncRNA-miRNA-mRNA regulatory network was constructed, and hub genes were selected through hub analysis. Enrichment analysis highlighted terms related to cell movement and gene expression regulation. We established a LINC00482-has-miR-6088-PRRC2B ceRNA network with diagnostic relevance for COPD. ROC analysis demonstrated the diagnostic value of these genes. Moreover, a positive correlation between LINC00482 and PRRC2B expression was observed in COPD PBMCs. The CTD database indicated their involvement in inflammatory responses.

Conclusion

In summary, our study not only identified pivotal hub genes in peripheral blood mononuclear cells (PBMCs) of COPD but also constructed a ceRNA regulatory network. This contributes to understanding the pathophysiological processes of COPD through bioinformatics analysis, expanding our knowledge of COPD, and providing a foundation for potential diagnostic and therapeutic targets for COPD.

Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Disease Patients with Underlying Alpha-1 Antitrypsin Deficiency: A Systematic Review and Practical Recommendations

Background

Alpha-1 antitrypsin deficiency (AATD) is an often-overlooked genetic condition that makes individuals susceptible to early onset of chronic obstructive pulmonary disease (COPD). The established benefits of exercise-based pulmonary rehabilitation (PR) for usual COPD patients are unclear for those with underlying AATD, especially given potentially differing muscle adaptations to exercise. This review seeks to compare PR outcomes between AATD and usual COPD patients and to consolidate current knowledge on exercise intervention outcomes for the AATD population.

Methods

A thorough search of 4 databases (Ovid, Medline, CINAHL, CENTRAL) was conducted based on 3 search concepts: (1) alpha-1 antitrypsin deficiency, (2) pulmonary rehabilitation OR exercise, and (3) muscle morphology. A dual review process and quality assessment were independently implemented throughout all stages of the review.

Results

Four studies highlighted modest exercise capacity and quality of life in AATD patients undergoing PR. However, one study reported unique muscle and mitochondrial responses compared to usual COPD patients. Additionally, a moderate exercise session did not alter pro-inflammatory cytokine levels in AATD patients, despite higher levels of tumor necrosis factor-α levels in muscle biopsies compared to usual COPD patients.

Conclusions

The current literature base insufficiently addresses the efficacy of PR on AATD, with indications that exercise adaptation may deviate from that of usual COPD patients. Further research is needed to optimize PR, particularly in identifying the most suitable exercise intensity, and delivery setting, and addressing specific educational needs for individuals with AATD.

Blood monocyte levels predict the risk of acute exacerbations of chronic obstructive pulmonary disease: a retrospective case-control study

Monocytes were critical cells in the innate immune system. Monocyte recruitment to the lungs is a crucial process of pathophysiology in chronic obstructive pulmonary disease (COPD). Current evidence on the association between the occurrence of acute exacerbations of COPD (AECOPD) and monocytes was unclear. This study aimed to examine whether blood monocytes are associated with the occurrence of AECOPD and to determine the specific blood monocyte level to predict AECOPD. A retrospective case-control study was conducted at Changhua Christian Hospital. A total of 444 eligible patients with COPD were included between January 2017 and December 2019. Restricted cubic splines were used to analyze the nonlinear relationships between continuous white blood cell values and the occurrence of AECOPD. The association between monocytes and the occurrence of AECOPD was assessed using the logistic, lasso, and ridge regression models. Restricted cubic splines revealed nonlinear associations among the monocyte level, the continuous value of the eosinophil-to-lymphocyte ratio, and the occurrence of AECOPD. The lowest risk of occurrence of AECOPD ranged from 7.4 to 10%; < 7.4% with an absolute count < 0.62 or > 10% indicated significant risk. No significant association was noted between the eosinophil-to-lymphocyte ratio categories in the tertiles (< 0.049, 0.049 to < 0.122, and ≥ 0.122) and the risk of AECOPD. A significantly higher risk was noted in the association of the occurrence of AECOPD with the CAT score; mMRC score; wheezing cough; preexisting chronic pulmonary disease; hypertension and malignancy; use of dual- and triple, and oral long-acting bronchodilators for COPD treatment; and WBC count. We reported a nonlinear relationship between monocytes and the occurrence of AECOPD. Patients with monocyte percentage of > 10% or < 7.4% with an absolute count < 0.62 had higher risk of occurrence of AECOPD. Overall, our study demonstrated the specific value of monocytes in identifying high risks of the occurrence of AECOPD; this value is an easy-to-obtain, inexpensive biomarker in patients with AECOPD and should be further investigated in future prospective clinical studies.

Effect of Smoking and Its Cessation on the Transcript Profile of Peripheral Monocytes in COPD Patients

Rationale

Smoking is the primary cause of chronic obstructive pulmonary disease (COPD); however, only 10–20% of smokers develop the disease suggesting possible genomic association in the causation of the disease. In the present study, we aimed to explore the whole genome transcriptomics of blood monocytes from COPD smokers (COPD-S), COPD Ex-smokers (COPD-ExS), Control smokers (CS), and Control Never-smokers (CNS) to understand the differential effects of smoking, COPD and that of smoking cessation.

Methods

Exploratory analyses in form of principal component analysis (PCA) and hierarchical component analysis (uHCA) were performed to evaluate the similarity in gene expression patterns, while differential expression analyses of different supervised groups of smokers and never smokers were performed to study the differential effect of smoking, COPD and smoking cessation. Differentially expressed genes among groups were subjected to post-hoc enrichment analysis. Candidate genes were subjected to external validation by quantitative RT-PCR experiments.

Results

CNS made a cluster completely segregated from the other three subgroups (CS, COPDS and COPD-ExS). About 550, 8 and 5 genes showed differential expression, respectively, between CNS and CS, between CS and COPD-S, and between COPD-S and COPD-ExS. Apoptosis, immune response, cell adhesion, and inflammation were the top process networks identified in enrichment analysis. Two candidate genes (CASP9 and TNFRSF1A) found to be integral to several pathways in enrichment analysis were validated in an external validation experiment.

Conclusion

Control never smokers had formed a cluster distinctively separated from all smokers (COPDS, COPD-ExS, and CS), while amongst all smokers, control smokers had aggregated in a separate cluster. Smoking cessation appeared beneficial if started at an early stage as many genes altered due to smoking started reverting towards the baseline, whereas only a few COPD-related genes showed reversal after smoking cessation.

In vitro study of the role of FOXO transcription factors in regulating cigarette smoke extract-induced autophagy

Cigarette smoking is the chief etiological factor for chronic obstructive pulmonary disease (COPD). Oxidative stress induced by cigarette smoke (CS) causes protein degradation, DNA damage, and cell death, thereby resulting in acute lung injury (ALI). In this regard, autophagy plays a critical role in regulating inflammatory responses by maintaining protein and organelle homeostasis and cellular viability. Expression of autophagy-related proteins (ARPs) is regulated by the fork head box class O (FOXO) transcription factors. In the current study, we examined the role of FOXO family proteins-FOXO1 and FOXO3a-in regulating CS extract (CSE)-induced autophagy. Using human lung adenocarcinoma cells with type II alveolar epithelial characteristics (A549), we observed CSE-mediated downregulation of FOXO3a. In contrast, there was a pronounced increase in the expression of FOXO1 at both the transcriptional and translational levels in the CSE-challenged cells compared with controls. Interestingly, knockdown of FOXO3a heightened the CSE-mediated increase in expression of cytokines/chemokines (IL-6, IL-8, and MCP-1), ARPs, and the FOXO1 transcription factor. Moreover, FOXO1 knockdown rescued CSE-mediated upregulation of ARPs in A549 cells. In addition, using the ROS inhibitor N-acetyl-L-cysteine (NAC), we observed abrogated mRNA expression of several ARPs and production of inflammatory cytokines/chemokines (IL-6, IL-8, MCP-1, and CCL-5) in the CSE-challenged cells suggesting an important role of ROS in regulating CSE-induced autophagy. Chromatin immunoprecipitation of FOXO1 and FOXO3a demonstrated increased binding of the former to promoter regions of autophagy genes- BECLIN1, ATG5, ATG12, ATG16, and LC3 in CSE challenged cells. These findings suggest the role of FOXO1 in regulating the expression of these genes during CSE exposure. Overall, our findings provide evidence for FOXO3a-dependent FOXO1-mediated regulation of autophagy in the CSE-challenged cells. Graphical abstract.

New Pharmacological Tools to Target Leukocyte Trafficking in Lung Disease

Infection and inflammation of the lung results in the recruitment of non-resident immune cells, including neutrophils, eosinophils and monocytes. This swift response should ensure clearance of the threat and resolution of stimuli which drive inflammation. However, once the threat is subdued this influx of immune cells should be followed by clearance of recruited cells through apoptosis and subsequent efferocytosis, expectoration or retrograde migration back into the circulation. This cycle of cell recruitment, containment of threat and then clearance of immune cells and repair is held in exquisite balance to limit host damage. Advanced age is often associated with detrimental changes to the balance described above. Cellular functions are altered including a reduced ability to traffic accurately towards inflammation, a reduced ability to clear pathogens and sustained inflammation. These changes, seen with age, are heightened in lung disease, and most chronic and acute lung diseases are associated with an exaggerated influx of immune cells, such as neutrophils, to the airways as well as considerable inflammation. Indeed, across many lung diseases, pathogenesis and progression has been associated with the sustained presence of trafficking cells, with examples including chronic diseases such as Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis and acute infections such as Pneumonia and Pneumonitis. In these instances, there is evidence that dysfunctional and sustained recruitment of cells to the airways not only increases host damage but impairs the hosts ability to effectively respond to microbial invasion. Targeting leukocyte migration in these instances, to normalise cellular responses, has therapeutic promise. In this review we discuss the current evidence to support the trafficking cell as an immunotherapeutic target in lung disease, and which potential mechanisms or pathways have shown promise in early drug trials, with a focus on the neutrophil, as the quintessential trafficking immune cell.

The adverse impact of cadmium on immune function and lung host defense

Cadmium (Cd) is a transition metal, also referred to as a heavy metal, that is naturally abundant in the earth's crust. It has no known benefit to humans. It is primarily released into our environment through mining and smelting in industrial processes and enters the food chain through uptake by plants from contaminated soil and water. In humans, Cd primarily enters the body through ingestion of foods and cigarette smoke and has an extremely long resident half-life in the body compared to other transition metals. Environmental workplace exposure is also a source through inhalation, although much less common. The principal organs adversely affected by Cd following acute and chronic exposure are the kidneys, bone, vasculature and lung. Cd adversely impacts cell function through changes in gene expression and signal transduction and is recognized as a carcinogen. Despite a substantial body of mechanistic studies in cells and animal models, the overall impact of Cd on innate immune function in humans remains poorly understood. The best evidence is perhaps alteration of reactive oxygen species balance and signaling in cells that regulate innate immunity causing alteration of the inflammatory response that is postulated to contribute to chronic diseases. Epidemiologic studies support this possibility since increased tissue levels in humans are strongly associated with leading chronic diseases including chronic obstructive pulmonary disease (COPD), which will be discussed in depth. Additional studies are required to understand how chronic exposure and accumulation of this leading environmental toxicant in vital organs negatively impact innate immune function and host defense leading to chronic disease in humans.

Lipid profile and atherogenic indices in patients with stable chronic obstructive pulmonary disease

BACKGROUND AND AIMS

Limited number of studies investigated lipid profile in chronic obstructive pulmonary disease (COPD) with inconsistent results. This study aimed to investigate lipid parameters in sera of patients with stable COPD and their associations with disease severity, smoking, comorbidities and therapy.

METHODS AND RESULTS

The study included 137 COPD patients and 95 controls. Triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were assessed. Non-HDL-C (NHC), atherogenic coefficient (AC), TG/HDL-C, atherogenic index of plasma (AIP), Castelli's risk index I and II (CRI-I, CRI-II), and monocyte to HDL ratio (MHR) were calculated. HDL-C and MHR were increased, while other lipid parameters and indices were decreased in COPD patients compared to healthy individuals. Smoking did not influence lipid parameters. However, lipid profile was altered only in more severe disease stages. AC, CRI-I and CRI-II showed positive association with lung function parameters in COPD patients, and negative with COPD multicomponent indices (ADO, BODCAT, BODEx, CODEx and DOSE). Combined model that included CRI-II, C-reactive protein, fibrinogen and white blood cells showed great diagnostic performances, and correctly classified 72% of study participants with an AUC of 0.800 (0.742-0.849), P < 0.001. Bronchodilator monotherapy and statins have opposite impact on TC, LDL-C and NHC, while TG, TG/HDL-C and AIP were increased in COPD patients with cardiovascular diseases.

CONCLUSION

Lipid disbalance is present in COPD, and it seems to occur later as the disease progresses. Further studies are needed to illuminate the underlying mechanism of dyslipidaemia.

The monocyte-dependent immune response to bacteria is suppressed in smoking-induced COPD

COPD patients have an increased susceptibility to bacterial airway infections that can induce exacerbations. In response to infections, circulating monocytes become recruited to the infected tissue and secrete cytokines. We hypothesized that this cytokine response is reduced in COPD. Cultured peripheral blood monocytes of never smokers (NS) and smokers without (S) and with COPD (3 study populations, n = 36-37) were stimulated with extracts of Haemophilus influenzae, Staphylococcus aureus, or Streptococcus pneumoniae or with four different pathogen-associated molecular patterns (PAMPs). Four cytokines and 9 PAMP-related signaling molecules were measured and compared between the groups. Granulocyte-macrophage-colony-stimulating-factor responses to all stimulants were reduced in S and COPD compared to NS. Tumor-necrosis-factor-α responses to all bacterial extracts, peptidoglycan, and lipopolysaccharide were reduced in S and/or COPD. Interleukin-10 responses to S. aureus and lipoteichoic acid were increased in COPD. Correlations to pack-years and lung function were found. The peptidoglycan-receptor NOD2 and the mRNA of the lipopolysaccharide-receptor TLR4 were reduced in S and COPD. Cytokine responses of monocytes to bacteria are suppressed by smoking and in COPD possibly due to NOD2 and TLR4 reduction and/or interleukin-10 increase. This might help to explain the increased susceptibility to bacterial infections. These systemic molecular pathologies might be targets for therapeutic strategies to prevent infection-induced exacerbations. KEY MESSAGES: COPD subjects have an increased susceptibility to bacterial infections. This implies defects in the immune response to bacteria and is critical for disease progression. The cytokine response of monocytes to bacteria is reduced in COPD. This might be due to a reduced NOD2 and TLR4 and an increased IL-10 expression. This can explain the increased susceptibility to infections and help to identify drug targets.

Blood monocyte profiles in COPD patients with PiMM and PiZZ α1-antitrypsin

Human blood monocytes are divided into populations based on the differential expression of CD14 and CD16 receptors: CD14 ⁺ CD16(classical), CD14 ⁺ CD16 ⁺ (intermediate), and CD14^-CD16⁺ (non-classical). Given their functional differences and their role in pathogenesis of chronic obstructive pulmonary disease (COPD), monocyte profiling is of clinical interest. Here we investigated blood monocyte subsets in clinically stable COPD patients with alpha1-antitrypsin (AAT) deficiency (PiZZ, n = 7) and with normal AAT variant (PiMM, n = 7). Peripheral whole blood was collected in sodium heparin tubes and incubated with LPS (from E. coli; 1 μg/ml) or placebo for 6 h at 37 °C, 5% CO2. To profile monocyte subsets we performed flow cytometry analysis based on HLA-DR and CD14/CD16 staining. HLA-DR + subsets of cells did not differ between PiZZ and PiMM COPD, and healthy controls (n = 7), used as a reference. Monocyte profiling, which express the CD14 and CD16, but not the HLA-DR (HLA-DR-) showed that intermediate monocytes subset was lowest in PiZZ group, and almost totally disappeared from blood treated with LPS. The non-classical subset was almost absent in PiZZ patients independently of LPS treatment. Recent studies demonstrate that non-classical monocytes exhibit a unique ability to protect the vascular endothelium under both homeostatic and inflammatory conditions whereas intermediate monocytes are recruited at a later stage of inflammation, and are associated with secretion of cytokines/chemokines and wound healing. Evident alterations in blood monocyte subsets together with a partial reduction of AAT levels, an important anti-inflammatory protein, can be key factors for the early manifestation of emphysema in some PiZZ AATD carriers.

Circulatory heavy metals (cadmium, lead, mercury, and chromium) inversely correlate with plasma GST activity and GSH level in COPD patients and impair NOX4/Nrf2/GCLC/GST signaling pathway in cultured monocytes

This study aims to examine the hypothesis that circulatory heavy metals may be associated with lung function decline and lower plasma GST activity and GSH level in COPD patients via activating monocytes mediated by impairing the NOX4/Nrf2/GCLC/GST signaling pathway. Results showed that the blood levels of heavy metals (cadmium, lead, mercury, and chromium) were significantly higher in COPD patients of coal mine site compared to the healthy controls. The levels of heavy metals in COPD patients were significantly and negatively correlated with lung function, GST activity, and GSH level. Using flowcytometry, fluorescence spectroscopy, and immunoblotting studies we have further demonstrated that treatment with individual heavy metals dose-dependently increased the NOX4 protein expression, intracellular ROS production, and decreased the Nrf2, GCLC, and GST protein expression, GST activity, and GSH level in THP-1 monocytes. None of the treatment caused any change in cell viability compared to control. In conclusion, this study suggests that circulatory heavy metals in COPD patients of coal mine site weakened the lung function, decreased the plasma GST activity and GSH level via impairing the NOX4/Nrf2/GCLC/GST signaling pathway in monocytes, which may cause monocyte activation and initiate the COPD pathophysiology.

Dysregulated Functions of Lung Macrophage Populations in COPD

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

Mechanical deformation induces depolarization of neutrophils

The transition of neutrophils from a resting state to a primed state is an essential requirement for their function as competent immune cells. This transition can be caused not only by chemical signals but also by mechanical perturbation. After cessation of either, these cells gradually revert to a quiescent state over 40 to 120 min. We use two biophysical tools, an optical stretcher and a novel microcirculation mimetic, to effect physiologically relevant mechanical deformations of single nonadherent human neutrophils. We establish quantitative morphological analysis and mechanical phenotyping as label-free markers of neutrophil priming. We show that continued mechanical deformation of primed cells can cause active depolarization, which occurs two orders of magnitude faster than by spontaneous depriming. This work provides a cellular-level mechanism that potentially explains recent clinical studies demonstrating the potential importance, and physiological role, of neutrophil depriming in vivo and the pathophysiological implications when this deactivation is impaired, especially in disorders such as acute lung injury.

Troglitazone, a PPAR-γ agonist, decreases LTC4 concentration in mononuclear cells in patients with asthma

BACKGROUND

Asthma is an inflammatory disorder with multiple mediators involved in the inflammatory response. Despite several attempts, no new anti-inflammatory drugs have been registered for asthma treatment for several years. However, thiazolidinediones, peroxisome proliferator-activated receptor agonists, have demonstrated some anti-inflammatory properties in various experimental settings. The aim of this study was to assess the influence of troglitazone on LTC₄ and 15-HETE concentrations. It also evaluates TNF-induced eotaxin synthesis in peripheral blood mononuclear cells from 14 patients with mild asthma and 13 healthy controls.

METHODS

PBMCs were isolated from the whole blood of the asthmatics and healthy subjects and pretreated with 0.1, 1 or 10μM of Troglitazone. The cells were then exposed to 10^-6M calcium jonophore or 10ng/ml TNF. The production and release of LTC₄, 15-HETE and eotaxin were then assessed.

RESULTS

Troglitazone caused a dose-dependent inhibition in LTC₄ synthesis in both asthmatics and healthy subjects. Troglitazone did not influence 15-HETE or eotaxin production in either asthmatic patients or in healthy individuals.

CONCLUSION

Due to its inhibition of LTC₄ synthesis, troglitazone therapy is an interesting potential therapeutic approach in asthma and other LTC₄ related inflammatory disorders.

Plausible Roles for RAGE in Conditions Exacerbated by Direct and Indirect (Secondhand) Smoke Exposure

Approximately 1 billion people smoke worldwide, and the burden placed on society by primary and secondhand smokers is expected to increase. Smoking is the leading risk factor for myriad health complications stemming from diverse pathogenic programs. First- and second-hand cigarette smoke contains thousands of constituents, including several carcinogens and cytotoxic chemicals that orchestrate chronic inflammatory responses and destructive remodeling events. In the current review, we outline details related to compromised pulmonary and systemic conditions related to smoke exposure. Specifically, data are discussed relative to impaired lung physiology, cancer mechanisms, maternal-fetal complications, cardiometabolic, and joint disorders in the context of smoke exposure exacerbations. As a general unifying mechanism, the receptor for advanced glycation end-products (RAGE) and its signaling axis is increasingly considered central to smoke-related pathogenesis. RAGE is a multi-ligand cell surface receptor whose expression increases following cigarette smoke exposure. RAGE signaling participates in the underpinning of inflammatory mechanisms mediated by requisite cytokines, chemokines, and remodeling enzymes. Understanding the biological contributions of RAGE during cigarette smoke-induced inflammation may provide critically important insight into the pathology of lung disease and systemic complications that combine during the demise of those exposed.

Oxidative Stress in COPD: Sources, Markers, and Potential Mechanisms

Markers of oxidative stress are increased in chronic obstructive pulmonary disease (COPD) and reactive oxygen species (ROS) are able to alter biological molecules, signaling pathways and antioxidant molecule function, many of which have been implicated in the pathogenesis of COPD. However, the involvement of ROS in the development and progression of COPD is not proven. Here, we discuss the sources of ROS, and the defences that have evolved to protect against their harmful effects. We address the role that ROS may have in the development and progression of COPD, as well as current therapeutic attempts at limiting the damage they cause. Evidence has indicated that the function of several key cells appears altered in COPD patients, and expression levels of important oxidant and antioxidant molecules may be abnormal. Therapeutic trials attempting to restore equilibrium to these molecules have not impacted upon all facets of disease and whilst the theory behind ROS influence in COPD appears sound, current models testing relevant pathways to tissue damage are limited. The heterogeneity seen in COPD patients presents a challenge to our understanding, and further research is essential to identify potential targets and stratified COPD patient populations where ROS therapies may be maximally efficacious.

Concomitant elevations of MMP-9, NGAL, proMMP-9/NGAL and neutrophil elastase in serum of smokers with chronic obstructive pulmonary disease

A growing body of evidence points towards smoking‐related phenotypic differences in chronic obstructive pulmonary disease (COPD). As COPD is associated with systemic inflammation, we determined whether smoking status is related to serum levels of matrix metalloproteinase‐9 (pro‐ and active MMP‐9), neutrophil gelatinase‐associated lipocalin (NGAL) and the proMMP‐9/NGAL complex in patients with COPD. Serum samples were collected in 100 stable‐phase COPD patients (82 smokers, 18 never‐smokers) and 28 healthy adults (21 smokers, 7 never‐smokers). Serum levels of studied factors were measured in ELISA. Our data provide the first evidence of simultaneously elevated serum levels of MMP‐9, NGAL and proMMP‐9/NGAL in COPD smokers. While the triad discriminated between smokers and non‐smokers in the COPD group, MMP‐9 and proMMP‐9/NGAL (but not NGAL) discriminated between smokers with and without COPD. Adjustment for age and smoking pack‐years did not alter the findings. Serum MMP‐9, NGAL and proMMP‐9/NGAL levels were not correlated with the GOLD stage or FEV1 decline. Furthermore, serum levels of neutrophil elastase (NE) and MMP‐3 (but not of IL‐6 and MMP‐12) were also higher in COPD smokers than in healthy smokers before and after adjustment for age and pack‐years. Among COPD smokers, levels of MMP‐9, NGAL and proMMP‐9/NGAL were positively correlated with NE (P < 0.0001) but not with the remaining factors. Gelatin zymography detected proMMP‐9 in serum samples of healthy and COPD smoking groups. Our results suggest that associated serum levels of proMMP‐9, NGAL, proMMP‐9/NGAL and NE may reflect the state of systemic inflammation in COPD related to cigarette smoking.

Evaluation of BODE index and its relationship with systemic inflammation mediated by proinflammatory biomarkers in patients with COPD

Introduction

BODE index, a multidimensional grading system which is based on Body mass index, airway Obstruction, Dyspnea scale, and Exercise capacity, has been increasingly used for the evaluation of chronic obstructive pulmonary disease (COPD). Many of the systemic manifestations of COPD are shown to be mediated by elevated levels of proinflammatory biomarkers.

Objective

We aimed to investigate the relationship between the BODE index, its components, disease severity, and proinflammatory biomarkers like C-reactive protein (CRP), tumor necrosis factor (TNF)-α, and interleukin (IL)-6.

Materials and methods

A cross-sectional study which included 290 clinically stable COPD patients and 80 smoker controls was conducted. Medical history, body mass index, pulmonary function tests, 6-minute walking test, and modified scale of Medical Research Council dyspnea scale were evaluated. BODE scores were determined. Systemic inflammation was evaluated with the measurement of CRP, TNF-α, and IL-6 in the serum samples of all studied subjects. The correlation between inflammatory biomarkers and BODE index was assessed in COPD patients.

Results

We found a significant relationship between COPD stages and BODE index. Our analysis showed significant association between systemic biomarkers and components of the BODE index. Both TNF-α and CRP levels exhibited weak but significant correlation with BODE index. Serum IL-6 concentrations exhibited significant correlation with 6-minute walking test, modified scale of Medical Research Council, and BODE index (r=0.201, P=0.004; r=0.068, P=0.001; and r=0.530, P=0.001, respectively). Also, an inverse and significant correlation was observed between BODE index and FEV1 (r=0.567, P=0.001). IL-6 exhibited a highly significant and inverse correlation with FEV1 (r=−0.580, P=0.001).

Conclusion

BODE index should be considered for evaluating patients with COPD. Also, IL-6 seems to be a potential biomarker that may enable determination of the severity and prediction of the course of the disease.

Impaired Blood Neutrophil Function in the Frequent Exacerbator of Chronic Obstructive Pulmonary Disease: A Proof-of-Concept Study

PURPOSE

The underlying biological mechanisms of the frequent exacerbator phenotype of COPD remain unclear. We compared systemic neutrophil function in COPD patients with or without frequent exacerbations.

METHODS

Whole blood from COPD frequent exacerbators (defined as ≥2 moderate-severe exacerbations in the previous 2 years) and non-exacerbators (no exacerbations in the preceding 2 years) was assayed for neutrophil function. Neutrophil function in healthy ex-smoking volunteers was also measured as a control (reference) group.

RESULTS

A total of 52 subjects were included in this study: 26 frequent exacerbators, 18 non-exacerbators and 8 healthy controls. COPD frequent exacerbators had blunted blood neutrophil fMLP-stimulated oxidative burst compared to both non-exacerbators (p < 0.01) and healthy controls (p < 0.001). There were no differences between COPD frequent exacerbators and non-exacerbators in blood neutrophil PMA-stimulated oxidative burst, but both COPD groups had reduced responses compared to healthy controls (p < 0.001). Bacterial-stimulated neutrophil degranulation was greater in frequent exacerbators than non-exacerbators (p < 0.05).

CONCLUSION

This study is the first to report aberrant receptor-mediated blood neutrophil function in the frequent exacerbator of COPD.

Cadmium attenuates the macrophage response to LPS through inhibition of the NF-κB pathway

Chronic obstructive pulmonary disease (COPD) in the U.S. is primarily caused by cigarette smoking. COPD patients are highly susceptible to respiratory infections in part due to alveolar macrophage dysfunction despite a substantial increase in macrophages in the lung. Cadmium (Cd) is a toxic metal that is concentrated within tobacco and accumulates in the lung of smokers. We hypothesized that Cd uptake into macrophages alters immune function thereby impairing the macrophage response to invading pathogens. Our hypothesis was tested by comparing primary human monocytes and macrophages, primary mouse bronchoalveolar lavage myeloid cells, and related cell lines. Strikingly, Cd exposure followed by LPS stimulation resulted in a dose-dependent, significant decrease in nuclear p65 activity in macrophages that was not observed in monocytes. This corresponded with Cd-mediated inhibition of IKKβ and an impaired ability to transcribe and release cytokines in response to LPS challenge in vivo. These findings provide novel evidence that Cd has the capacity to disrupt macrophage immune function compared with monocytes. Importantly, Cd results in immune dysfunction in macrophages through inhibition of the NF-κB signaling pathway. Based on these findings, we provide new evidence that Cd contributes to immune dysfunction in the lung of COPD subjects and may increase susceptibility to infection.

Identification of MMP-9 as a biomarker for detecting progression of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex immunological disease with multiple pathological features that is primarily induced by smoking together with additional genetic risk factors. COPD is frequently underdiagnosed; forced expiratory volume in the first second (FEV1) is considered to be the main diagnostic measure for COPD, yet it is insufficiently sensitive to monitor disease progression. Biomarkers capable of monitoring COPD progression and severity are needed. In this report, we evaluated matrix metalloproteinase-9 (MMP-9) as an early marker for the detection and staging of COPD, by assessing the mRNA levels of MMP-9 in peripheral blood samples collected from 22 COPD patients, 6 asymptomatic smokers, and 5 healthy controls. Our results demonstrate that the mRNA levels of MMP-9 increased more than two-fold in severe COPD relative to non-COPD smokers or moderate COPD groups. Moreover, in the very severe COPD group, MMP-9 mRNA levels showed a 4-fold increase relative to the non-COPD smokers or the moderate COPD groups, while there was a mild increase (∼40%) when compared to the severe COPD group. Taken together, our results suggest that MMP-9 serves as a biomarker for the grade and severity of COPD.

Novel aspects of pathogenesis and regeneration mechanisms in COPD

Chronic obstructive pulmonary disease (COPD), a major cause of death and morbidity worldwide, is characterized by expiratory airflow limitation that is not fully reversible, deregulated chronic inflammation, and emphysematous destruction of the lungs. Despite the fact that COPD is a steadily growing global healthcare problem, the conventional therapies remain palliative, and regenerative approaches for disease management are not available yet. We aim to provide an overview of key reviews, experimental, and clinical studies addressing lung emphysema development and repair mechanisms published in the past decade. Novel aspects discussed herein include integral revision of the literature focused on lung microflora changes in COPD, autoimmune component of the disease, and environmental risk factors other than cigarette smoke. The time span of studies on COPD, including emphysema, chronic bronchitis, and asthmatic bronchitis, covers almost 200 years, and several crucial mechanisms of COPD pathogenesis are described and studied. However, we still lack the holistic understanding of COPD development and the exact picture of the time-course and interplay of the events during stable, exacerbated, corticosteroid-treated COPD states, and transitions in-between. Several generally recognized mechanisms will be discussed shortly herein, ie, unregulated inflammation, proteolysis/antiproteolysis imbalance, and destroyed repair mechanisms, while novel topics such as deviated microbiota, air pollutants-related damage, and autoimmune process within the lung tissue will be discussed more extensively. Considerable influx of new data from the clinic, in vivo and in vitro studies stimulate to search for novel concise explanation and holistic understanding of COPD nowadays.

Exacerbating factors induce different gene expression profiles in peripheral blood mononuclear cells from asthmatics, patients with chronic obstructive pulmonary disease and healthy subjects

BACKGROUND

Despite several common phenotypic features, chronic obstructive pulmonary disease (COPD) and severe asthma differ with regard to their causative factors and pathophysiology. Both diseases may be exacerbated by environmental factors, however, the molecular profiles of disease episodes have not been comprehensively studied. We identified differences in gene and protein expression profiles expressed by peripheral blood mononuclear cells (PBMC) of COPD patients, patients with atopic asthma and healthy subjects when challenged with exacerbating factors in vitro: lipopolysaccharide (LPS), house dust mite (HDM) and cat allergen.

METHODS

PBMC isolated from patients with severe atopic asthma and COPD, as well as healthy subjects were stimulated with rDer p 1 DG, rFel d 1 DG and LPS. The changes in the expression of 47 genes belonging to five groups (phospholipase A2, eicosanoids, transcription factors, cytokines and airway remodeling) were studied using TaqMan low density array cards. Immunoblotting was used to study relative protein expression.

RESULTS

rDer p 1 significantly up-regulated the expression of PLA2G4A, PLA2G6, PLA2G15, CYSLTR1, LB4R2, PTGS1, PTGS2, FOXP1, GATA3, HDAC2, IREB2, PPARG, STAT4, TSLP and CHI3L1 genes in asthmatics in comparison to healthy subjects. LPS induced significant expression of ANXA1 and LTA4H in asthmatics when compared to COPD patients and healthy subjects. SOX6,STAT4 and IL1RL1 were induced in COPD after LPS stimulation. Analysis of protein expression revealed a pattern similar to mRNA expression.

CONCLUSIONS

LPS-induced exacerbation of asthma and COPD is characterized by differential expression of selected genes in PBMC. HDM allergen changed the expression profile of inflammatory genes between patients with asthma of atopic origin and healthy controls.

Function of monocytes and monocyte-derived macrophages in α1-antitrypsin deficiency

α1-antitrypsin deficiency is the most widely recognised genetic disorder causing chronic obstructive pulmonary disease (COPD). Mutant Z α1-antitrypsin expression has previously been linked to intracellular accumulation and polymerisation of this proteinase inhibitor. Subsequently, this has been described to underlie an exaggerated endoplasmic reticulum stress response and enhanced nuclear factor-κB signalling. However, whether monocyte-derived macrophages display the same features remains unknown.

Monocytes from homozygous PiZZ α1-antitrypsin deficiency patients and PiMM controls were cultured for 6 days in the presence of granulocyte-macrophage or macrophage colony-stimulating factor to obtain pro- and anti-inflammatory macrophages (mφ-1 and mφ-2, respectively).

We first showed that, in contrast to monocytes, pre-stressed mφ-1 and mφ-2 from healthy blood donors display an enhanced endoplasmic reticulum stress response upon a lipopolysaccharide trigger (XBP1 splicing, CHOP, GADD34 and GRP78 mRNA). However, this endoplasmic reticulum stress response did not differ between monocyte-derived macrophages and monocytes from ZZ patients compared to MM controls. Furthermore, these ZZ cells do not secrete higher cytokine levels, and α1-antitrypsin polymers were not detectable by ELISA.

These data suggest that monocyte-derived macrophages are not the local source of Z α1-antitrypsin polymers found in the lung and that endoplasmic reticulum stress and pro-inflammatory cytokine release is not altered.

Serum cytokine profiling and enrichment analysis reveal the involvement of immunological and inflammatory pathways in stable patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major global health problem. It results from chronic inflammation and causes irreversible airway damage. Levels of different serum cytokines could be surrogate biomarkers for inflammation and lung function in COPD. We aimed to determine the serum levels of different biomarkers in COPD patients, the association between cytokine levels and various prognostic parameters, and the key pathways/networks involved in stable COPD. In this study, serum levels of 48 cytokines were examined by multiplex assays in 30 subjects (control, n=9; COPD, n=21). Relationships between serum biomarkers and forced expiratory volume in 1 second, peak oxygen uptake, body mass index, dyspnea score, and smoking were assessed. Enrichment pathways and network analyses were implemented, using a list of cytokines showing differential expression between healthy controls and patients with COPD by Cytoscape and GeneGo Metacore™ software (Thomson-Reuters Corporation, New York, NY, USA). Concentrations of cutaneous T-cell attracting chemokine, eotaxin, hepatocyte growth factor, interleukin 6 (IL-6), IL-16, and stem cell factor are significantly higher in COPD patients compared with in control patients. Notably, this study identifies stem cell factor as a biomarker for COPD. Multiple regression analysis predicts that cutaneous T-cell-attracting chemokine, eotaxin, IL-6, and stem cell factor are inversely associated with forced expiratory volume in 1 second and peak oxygen uptake change, whereas smoking is related to eotaxin and hepatocyte growth factor changes. Enrichment pathways and network analyses reveal the potential involvement of specific inflammatory and immune process pathways in COPD. Identified network interaction and regulation of different cytokines would pave the way for deeper insight into mechanisms of the disease process.

Inflammatory cytokine response to exercise in alpha-1-antitrypsin deficient COPD patients 'on' or 'off' augmentation therapy

BACKGROUND

There is still limited information on systemic inflammation in alpha-1-antitrypsin-deficient (AATD) COPD patients and what effect alpha-1-antitrypsin augmentation therapy and/or exercise might have on circulating inflammatory cytokines. We hypothesized that AATD COPD patients on augmentation therapy (AATD + AUG) would have lower circulating and skeletal muscle inflammatory cytokines compared to AATD COPD patients not receiving augmentation therapy (AATD-AUG) and/or the typical non-AATD (COPD) patient. We also hypothesized that cytokine response to exercise would be lower in AATD + AUG compared to AATD-AUG or COPD subjects.

METHODS

Arterial and femoral venous concentration and skeletal muscle expression of TNFα, IL-6, IL-1β and CRP were measured at rest, during and up to 4-hours after 50% maximal 1-hour knee extensor exercise in all COPD patient groups, including 2 additional groups (i.e. AATD with normal lung function, and healthy age-/activity-matched controls).

RESULTS

Circulating CRP was higher in AATD + AUG (4.7 ± 1.6 mg/dL) and AATD-AUG (3.3 ± 1.2 mg/dL) compared to healthy controls (1.5 ± 0.3 mg/dL, p < 0.05), but lower in AATD compared to non-AATD-COPD patients (6.1 ± 2.6 mg/dL, p < 0.05). TNFα, IL-6 and IL-1β were significantly increased by 1.7-, 1.7-, and 4.7-fold, respectively, in non-AATD COPD compared to AATD COPD (p < 0.05), and 1.3-, 1.7-, and 2.2-fold, respectively, compared to healthy subjects (p < 0.05). Skeletal muscle TNFα was on average 3-4 fold greater in AATD-AUG compared to the other groups (p < 0.05). Exercise showed no effect on these cytokines in any of our patient groups.

CONCLUSION

These data show that AATD COPD patients do not experience the same chronic systemic inflammation and exhibit reduced inflammation compared to non-AATD COPD patients. Augmentation therapy may help to improve muscle efflux of TNFα and reduce muscle TNFα concentration, but showed no effect on IL-6, IL-1β or CRP.

Interleukin-33/ST2 signaling promotes production of interleukin-6 and interleukin-8 in systemic inflammation in cigarette smoke-induced chronic obstructive pulmonary disease mice

Interleukin-33 is a newly described member of the interleukin-1 family. Recent research suggests that IL-33 is increased in lungs and plays a critical role in chronic airway inflammation in cigarette smoke-induced chronic obstructive pulmonary disease (COPD) mice. To determine the role of IL-33 in systemic inflammation, we induced COPD mice models by passive cigarette smoking and identified the IL-33 expression in bronchial endothelial cells and peripheral blood mononuclear cells (PBMCs) of them. After isolation, PBMCs were cultured and stimulated in vitro. We measured expressions of interleukin-6 and interleukin-8 in PBMCs in different groups. The expression of IL-33 in bronchial endothelial cells and PBMCs of COPD mice were highly expressed. Stimulated by cigarette smoke extract (CSE), the expression of IL-6 and IL-8 were induced and enhanced by IL-33. PBMCs of COPD mice produced more IL-6 and IL-8 stimulated by CSE and IL-33. Expression of IL-6 and IL-8 were decreased when stimulated by IL-33 together with soluble ST2. The mRNA production of ST2 in IL-33 stimulated PBMCs was increased. Being pretreated with several kinds of MAPK inhibitors, the secretions of IL-6 and IL-8 in PBMCs did not decrease except for the p38 MAPK inhibitor. We found that IL-33 could induce and enhance the expression of IL-6 and IL-8 in PBMCs of COPD mice via p38 MAPK pathway, and it is a promoter of the IL-6 and IL-8 production in systemic inflammation in COPD mice.

α₁-Antitrypsin modulates lung endothelial cell inflammatory responses to TNF-α

α₁-Antitrypsin (A1AT) is an acute-phase reactant, but also a major protective factor against the development of chronic obstructive pulmonary disease, a complex disease with sustained chronic inflammation. The lung-protective effects of A1AT have been attributed to the inhibition of proteases involved in lung matrix fragmentation, macrophage activation, and endothelial-cell apoptosis. More recently, A1AT has been shown to directly interact with or modulate the actions of cytokines such as TNF-α or IL-1 in inflammatory cells, but its effect on the lung endothelium, an active participant in the amplification and resolution of inflammation, has received little attention. An important role of A1AT in modulating lung endothelial inflammatory responses is expected, given the high concentrations of circulating A1AT during inflammation and its active uptake by endothelial cells. We investigated the role of A1AT in primary lung microvascular endothelial cell activation by relevant cytokines such as TNF-α or IL-1β. Despite an initial marked augmentation of TNF-α self-induced transcription, A1AT inhibited TNF-α receptor 1 up-regulation and significantly reduced TNF-α secretion, effects that were associated with inhibition of TNF-α-converting enzyme activity. Furthermore, A1AT inhibited calpain activity, whose activation by TNF-α contributed to decreased intracellular A1AT concentrations. These data indicate that A1AT initially facilitates acute responses of the endothelium to TNF-α, followed by selective inhibition of TNF-α-induced-self amplification, which may assist the vasculature in the resolution of chronic inflammation.

Cardiovascular disease in COPD: mechanisms

It is now well established that cardiovascular disease contributes significantly to both morbidity and mortality in COPD. Shared risk factors for cardiovascular disease and COPD, such as smoking, low socioeconomic class, and a sedentary lifestyle contribute to the natural history of each of these conditions. However, it is now apparent that alternative, novel mechanisms are involved in the pathogenesis of cardiovascular disease, and these may play an important role in driving the increased cardiovascular risk associated with COPD. In this article, we discuss the potential mechanisms that link COPD to an increased risk of cardiovascular disease.

Peripheral compartment innate immune response to Haemophilus influenzae and Streptococcus pneumoniae in chronic obstructive pulmonary disease patients

Alterations in innate immunity that predispose to chronic obstructive pulmonary disease (COPD) exacerbations are poorly understood. We examined innate immunity gene expression in peripheral blood polymorphonuclear leukocytes (PMN) and monocytes stimulated by Haemophilus influenzae and Streptococcus pneumoniae. Thirty COPD patients (15 rapid and 15 non-rapid lung function decliners) and 15 smokers without COPD were studied. Protein expression of IL-8, IL-6, TNF-α and IFN-γ (especially monocytes) increased with bacterial challenge. In monocytes stimulated with S. pneumoniae, TNF-α protein expression was higher in COPD (non-rapid decliners) than in smokers. In co-cultures of monocytes and PMN, mRNA expression of TGF-β1 and MYD88 was up-regulated, and CD14, TLR2 and IFN-γ down-regulated with H. influenzae challenge. TNF-α mRNA expression was increased with H. influenzae challenge in COPD. Cytokine responses were similar between rapid and non-rapid decliners. TNF-α expression was up-regulated in non-rapid decliners in response to H. influenzae (monocytes) and S. pneumoniae (co-culture of monocytes and PMN). Exposure to bacterial pathogens causes characteristic innate immune responses in peripheral blood monocytes and PMN in COPD. Bacterial exposure significantly alters the expression of TNF-α in COPD patients, although not consistently. There did not appear to be major differences in innate immune responses between rapid and non-rapid decliners.

Selection of disease-specific biomarkers by integrating inflammatory mediators with clinical informatics in AECOPD patients: a preliminary study

Systemic inflammation is a major factor influencing the outcome and quality of patient with chronic obstructive pulmonary disease (COPD) and acute exacerbations (AECOPD). Because of the inflammatory complexity, a great challenge is still confronted to optimize the identification and validation of disease-specific biomarkers. This study aimed at developing a new protocol of specific biomarker evaluation by integrating proteomic profiles of inflammatory mediators with clinical informatics in AECOPD patients, understand better their function and signal networks. Plasma samples were collected from healthy non-smokers or patients with stable COPD (sCOPD) or AECOPD on days 1 and 3 of the admission and discharging day (day 7–10). Forty chemokines were measured using a chemokine multiplex antibody array. Clinical informatics was achieved by a Digital Evaluation Score System (DESS) for assessing severity of patients. Chemokine data was compared among different groups and its correlation with DESS scores was performed by SPSS software. Of 40 chemokines, 30 showed significant difference between sCOPD patients and healthy controls, 16 between AECOPD patients and controls and 13 between AECOPD patients and both sCOPD and controls, including BTC, IL-9, IL-18Bpa, CCL22,CCL23, CCL25, CCL28, CTACK, LIGHT, MSPa, MCP-3, MCP-4 and OPN. Of them, some had significant correlation with DESS scores. There is a disease-specific profile of inflammatory mediators in COPD and AECOPD patients which may have a potential diagnostics together with clinical informatics of patients. Our preliminary study suggested that integration of proteomics with clinical informatics can be a new way to validate and optimize disease-special biomarkers.

Viscoelastic properties of differentiating blood cells are fate- and function-dependent

Although cellular mechanical properties are known to alter during stem cell differentiation, understanding of the functional relevance of such alterations is incomplete. Here, we show that during the course of differentiation of human myeloid precursor cells into three different lineages, the cells alter their viscoelastic properties, measured using an optical stretcher, to suit their ultimate fate and function. Myeloid cells circulating in blood have to be advected through constrictions in blood vessels, engendering the need for compliance at short time-scales (<seconds). Intriguingly, only the two circulating myeloid cell types have increased short time scale compliance and flow better through microfluidic constrictions. Moreover, all three differentiated cell types reduce their steady-state viscosity by more than 50% and show over 140% relative increase in their ability to migrate through tissue-like pores at long time-scales (>minutes), compared to undifferentiated cells. These findings suggest that reduction in steady-state viscosity is a physiological adaptation for enhanced migration through tissues. Our results indicate that the material properties of cells define their function, can be used as a cell differentiation marker and could serve as target for novel therapies.

Chronic obstructive pulmonary disease patients have greater systemic responsiveness to ex vivo stimulation with swine dust extract and its components versus healthy volunteers

Chronic obstructive pulmonary disease (COPD) is characterized by an airway and systemic inflammatory response. Bioaerosols/organic dusts are important agricultural pollutants that may lead to COPD. These environments are complex, containing a rich source of various microbial components. The objective of this study was to determine whether individuals with COPD have enhanced systemic responsiveness to settled swine facility organic dust extract (ODE) or its main pathogenic components (peptidoglycan [PGN], lipopolysaccharide [LPS]) versus healthy volunteers. A modified whole blood assay (WBA) that included occupational levels of ODE and concentrations of LPS and PGN found in ODE was used to determine systemic responsiveness (mediator release), and sputum inflammatory markers were measured to explore for systemic and airway associations. Sputum samples were evaluated for cell counts, and tumor necrosis factor (TNF)-α, interleukin (IL)-8/CXCL8, IL-6, and IL-10. Ex vivo whole blood stimulation with ODE, LPS, and PGN each resulted in significant mediator release in all subjects, with the highest occurring with ODE; PGN resulted in significantly enhanced TNF-α and IL-8 as compared to LPS. COPD subjects demonstrated greater systemic responsiveness using the modified WBA versus healthy controls. Within COPD subjects, blood baseline TNF-α, IL-8, and IL-10 and ODE-, PGN-, and LPS-stimulated IL-8 levels significantly correlated with lung function. In conclusion, dust-induced mediator release was robust, and PGN, in part, resembled dust-induced mediator release. Subjects with COPD demonstrated increased mediator release following ex vivo whole blood stimulation with bioaerosol components, suggesting that circulating blood cells in COPD subjects may be primed to respond greater to microbial/inflammatory insult.

Altered monocyte and fibrocyte phenotype and function in scleroderma interstitial lung disease: reversal by caveolin-1 scaffolding domain peptide

Interstitial lung disease (ILD) is a major cause of morbidity and mortality in scleroderma (systemic sclerosis, or SSc). Fibrocytes are a monocyte-derived cell population implicated in the pathogenesis of fibrosing disorders. Given the recently recognized importance of caveolin-1 in regulating function and signaling in SSc monocytes, in the present study we examined the role of caveolin-1 in the migration and/or trafficking and phenotype of monocytes and fibrocytes in fibrotic lung disease in human patients and an animal model. These studies fill a gap in our understanding of how monocytes and fibrocytes contribute to SSc-ILD pathology. We found that C-X-C chemokine receptor type 4-positive (CXCR4+)/collagen I-positive (ColI+), CD34+/ColI+ and CD45+/ColI+ cells are present in SSc-ILD lungs, but not in control lungs, with CXCR4+ cells being most prevalent. Expression of CXCR4 and its ligand, stromal cell-derived factor 1 (CXCL12), are also highly upregulated in SSc-ILD lung tissue. SSc monocytes, which lack caveolin-1 and therefore overexpress CXCR4, exhibit almost sevenfold increased migration toward CXCL12 compared to control monocytes. Restoration of caveolin-1 function by administering the caveolin scaffolding domain (CSD) peptide reverses this hypermigration. Similarly, transforming growth factor β-treated normal monocytes lose caveolin-1, overexpress CXCR4 and exhibit 15-fold increased monocyte migration that is CSD peptide-sensitive. SSc monocytes exhibit a different phenotype than normal monocytes, expressing high levels of ColI, CD14 and CD34. Because ColI+/CD14+ cells are prevalent in SSc blood, we looked for such cells in lung tissue and confirmed their presence in SSc-ILD lungs but not in normal lungs. Finally, in the bleomycin model of lung fibrosis, we show that CSD peptide diminishes fibrocyte accumulation in the lungs. Our results suggest that low caveolin-1 in SSc monocytes contributes to ILD via effects on cell migration and phenotype and that the hyperaccumulation of fibrocytes in SSc-ILD may result from the altered phenotype and migratory activity of their monocyte precursors.

An agent-based model of inflammation and fibrosis following particulate exposure in the lung

Inflammation and airway remodeling occur in a variety of airway diseases. Modeling aspects of the inflammatory and fibrotic processes following repeated exposure to particulate matter may provide insights into a spectrum of airway diseases, as well as prevention/treatment strategies. An agent-based model (ABM) was created to examine the response of an abstracted population of inflammatory cells (nominally macrophages, but possibly including other inflammatory cells such as lymphocytes) and cells involved in remodeling (nominally fibroblasts) to particulate exposure. The model focused on a limited number of relevant interactions, specifically those among macrophages, fibroblasts, a pro-inflammatory cytokine (TNF-α), an anti-inflammatory cytokine (TGF-β1), collagen deposition, and tissue damage. The model yielded three distinct states that were equated with (1) self-resolving inflammation and a return to baseline, (2) a pro-inflammatory process of localized tissue damage and fibrosis, and (3) elevated pro- and anti-inflammatory cytokines, persistent tissue damage, and fibrosis outcomes. Experimental results consistent with these predicted states were observed in histology sections of lung tissue from mice exposed to particulate matter. Systematic in silico studies suggested that the development of each state depended primarily upon the degree and duration of exposure. Thus, a relatively simple ABM resulted in several, biologically feasible, emergent states, suggesting that the model captures certain salient features of inflammation following exposure of the lung to particulate matter. This ABM may hold future utility in the setting of airway disease resulting from inflammation and fibrosis following particulate exposure.

Chronic obstructive pulmonary disease-specific gene expression signatures of alveolar macrophages as well as peripheral blood monocytes overlap and correlate with lung function

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease characterized by progressive airflow limitation and significant extrapulmonary (systemic) effects that lead to co-morbid conditions, though the pathomechanism of COPD is largely undetermined. Alveolar macrophages (AM) derived from peripheral monocytes (MO) appear to play a key role in initiating and/or sustaining disease progression.

OBJECTIVES

To identify disease- and cell type-specific gene expression profiles and potential overlaps in those in order to diagnose COPD, characterize its progression and determine the effect of drug treatment.

METHOD

Global gene expression analysis was used for primary screening in order to obtain expression signatures of AMs and circulating MOs of COPD patients and healthy controls. The results of microarray analyses of AMs (20 controls and 26 COPD patients) and MOs (16 controls and 22 COPD patients) were confirmed and validated by real-time quantitative polymerase chain reaction.

RESULTS

We have identified gene sets specifically associated with COPD in AMs and MOs. There were overlapping genes between the two cell types. Our data also show that COPD-specific gene expression signatures in AMs and MOs correlate with percent of predicted FEV(1).

CONCLUSION

Disease-specific and overlapping gene expression signatures can be defined in lung-derived macrophages and also in circulating monocytes. Some of the validated expression changes in both cell types correlate with lung function and therefore could serve as biomarkers of disease progression.

[Role of inflammation in the etiopathogenesis of COPD]

Inflammation is one of the first immune system responses to any type of aggression. As with any type of aggression, the lesion produced by inhalation of tobacco smoke prompts an innate inflammatory response. Subsequently, this lesion is stimulated by the release of various chemical factors that enhance the inflammatory response and, finally--depending on the type of aggression--acquired immunity is activated, which, mediated by lymphocyte participation, serves to establish a physical barrier against the propagation of the lesion and to aid repair of the damaged pulmonary tissue. However, the balance between inflammation and repair is not always maintained, as is the case in chronic obstructive pulmonary disease (COPD), in which marked changes appear in the architecture of the airways, alveolar spaces and pulmonary arteries, forming the structural background of the functional changes characteristic of this disease. COPD is basically a pulmonary disease but data are available on the existence of associated systemic inflammation. The origins of this systemic inflammation are unclear: some information indicates that tobacco smoke is a direct origin common to local and systemic inflammation, while other data point to primary pulmonary inflammation that secondarily produces systemic involvement. The present review describes the main mechanisms involved in both pulmonary and systemic inflammation in COPD.

Signal transduction pathways linking the activation of alveolar macrophages with the recruitment of neutrophils to lungs in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem. It is predicted by the World Health Organization to become the third most common cause of death and the fifth most common cause of disability in the world by 2020. COPD is a complex inflammatory disease involving several types of inflammatory cells and multiple inflammatory mediators. Although abnormal numbers of inflammatory cells such as macrophages, dendritic cells, neutrophils, and T lymphocytes have been documented in COPD, the relationship between these cell types and the sequence of their appearance and persistence is largely unknown. Alveolar macrophages have been identified as one of the major cell types that plays a key role in orchestrating the inflammatory events associated with the pathophysiology of COPD. One of the major functions of macrophages is the secretion of chemotactic factors and this function is markedly increased on exposure to cigarette smoke (CS). This enhanced release of chemoattractants results in increased lung neutrophil infiltration, which is thought to be a key event in the development of COPD. The molecular basis for this amplified inflammatory response is not very clear, but it could be due to an alteration in signal transduction pathways within the macrophage. Based on existing literature, an attempt has been made to create a comprehensive review of the signal transduction pathways that link the activation of macrophages with the increased recruitment of neutrophils into the airways. Some of the major stimuli that activate macrophages and cause them to secrete chemotactic factors have been identified as CS, wood smoke, ozone, bacterial endotoxin, and proinflammatory cytokines such as interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. These stimuli seem to activate mainly redox-sensitive transcription factors such as nuclear factor (NF)-kappa B and activator protein (AP)-1, both of which play a major role in the synthesis and secretion of chemotactic factors such as IL-8 and leukotriene B(4) (LTB(4)). The pathways involved in the synthesis and secretion of other factors such as macrophage chemotactic protein-1 (MCP-1) and growth-related oncogene-alpha (Gro-alpha) have also been reviewed.

Low plasma levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFalpha), and vascular endothelial growth factor (VEGF) in patients with alpha1-antitrypsin deficiency-related fibromyalgia

Abnormalities in blood inflammatory markers have been associated with clinical manifestations and the pathogenesis of the fibromyalgia syndrome (FMS); a relationship between inherited alpha1-antitrypsin deficiency (AATD) and FMS has also been recently raised. In this study, plasma levels of inflammatory markers in FMS patients with and without AATD have been investigated. Blood samples from 138 age-matched females (79 FMS) and 59 general population (GP), with normal MM [n = 82 (59.4%)] and with MS, MZ, SZ, and ZZ AATD genotypes [n = 56 (40.6%)], were analyzed by ELISA for monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFalpha), soluble TNFalpha receptors I and II, interleukin-8, and vascular endothelial growth factor (VEGF). Plasma levels of MCP-1, VEGF, and TNFalpha were significantly lower in FMS and GP subjects with AATD compared with those with normal MM-AAT genotypes. Moreover, plasma levels of MCP-1, VEGF, and TNFalpha were lower in AATD subjects with FMS than in those without FMS (P = 0.000, 0.000, and 0.046, respectively). No statistical differences were found for the other substances measured. Furthermore, a logistic regression model based on plasma MCP-1 cutoff value of <or=130 pg/ml allowed us to discriminate between FMS and GP subjects with a sensitivity of about 93% and a specificity of 79%. Low plasma levels of MCP-1, VEGF, and TNFalpha are related to AATD, although more markedly in FMS patients. Thus, hypotheses considering FMS as an inflammatory condition related to high plasma levels of inflammatory biomarkers cannot be supported.

Accelerated lung aging: a novel pathogenic mechanism of chronic obstructive pulmonary disease (COPD)

An enhanced or abnormal inflammatory response to the lungs to inhaled particles and gases, usually from cigarette smoke, is considered to be a general pathogenic mechanism in COPD (chronic obstructive pulmonary disease). Activation of leucocytes and the development of oxidant-antioxidant and protease-anti-protease imbalances are thought to be important aspects of this enhanced inflammatory response to cigarette smoke. The mechanisms involved in the perpetuation of the inflammatory response in the lungs in patients who develop COPD, even after smoking cessation, are not fully established and are key to our understanding of the pathogenic mechanisms in COPD and may be important for the development of new therapies. There is a relationship between chronic inflammatory diseases and aging, and the processes involved in aging may provide a novel mechanism in the pathogenesis of COPD. There is good evidence linking aging and COPD. During normal aging, pulmonary function deteriorates progressively and pulmonary inflammation increases, accompanied in the lungs by the features of emphysema. These features are accelerated in COPD. Emphysema is associated with markers of accelerated aging in the lungs, and COPD is also associated with features of accelerated aging in other organs, such as the cardiovascular and musculoskeletal systems. Cigarette smoke and other oxidative stresses result in cellular senescence and accelerate lung aging. There is also evidence that anti-aging molecules such as histone deacetylases and sirtuins are decreased in the lungs of COPD patients, compared with smokers without COPD, resulting in enhanced inflammation and further progression of COPD. The processes involved in accelerated aging may provide novel targets for therapy in COPD. The present article reviews the evidence for accelerated aging as a mechanism in the pathogenesis of COPD.