Epigenetic mechanisms in COPD: implications for pathogenesis and drug discovery

Comprehensive Analysis of a Competing Endogenous RNA Co-Expression Network in Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) is the main cause of mortality world widely. Non-coding RNAs (lncRNAs) and associated competitive endogenous RNAs (ceRNAs) networks were recently proved to lead to mRNA gene expression downregulation but were still unclear in COPD. This study aims to investigate and elucidate the mechanisms underlying the involvement of ceRNA co-expression networks in COPD pathogenesis.

Methods

Obtained expression signature of data from the Gene Expression Omnibus database and compared the differentially expression of mRNAs and miRNAs between COPD patients and healthy smokers. Predicted the miRNA-lncRNA and miRNA-mRNA interaction using online library and employed CIBERSORT to measure the proportions of the 22 immune cells in the COPD and control groups.

Results

Established a ceRNA-network comprising 11 lncRNAs, 5 miRNAs, and 16 mRNAs. Using the weighted correlation network analysis method, we identified hub genes and hub miRNAs and obtained one core sub-network, XIST, FGD5-AS1, KCNQ1OT1, HOXA11-AS, LINC00667, H19, PRKCQ-AS1, NUTM2A-AS1/has-mir-454-3p/ZNF678, PRRG4. COPD patients had different proportions of immune cells than controls, and these variations were associated with the magnitude of pulmonary function parameters.

Conclusion

The ceRNA-network, particularly the core sub-network, may be a putative goal for COPD, in which specific immune cells were involved.

Associations between GrimAge acceleration and pulmonary function in the Coronary Artery Risk Development in Young Adults (CARDIA) study

Background: The objective of this research was to determine whether pulmonary function is associated with epigenetic aging (GrimAge) and whether GrimAge predicts emphysema. Methods: This prospective study examined 1042 participants enrolled as part of a community-based longitudinal cohort. The cross-sectional associations between pulmonary function and GrimAge, measured at study year (Y) 20 (participant ages 40-45 years), and prospective associations with emphysema at Y25 were examined. Results: At Y20, forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) were negatively associated with GrimAge; for Y0-Y10 cumulative measures, only the FEV1/FVC ratio was associated with GrimAge at Y15 and Y20. Emphysema at Y25 was associated with GrimAge at Y15 and Y20. Conclusion: Pulmonary function was associated with GrimAge during early and mid-life; GrimAge partially mediated the association between pulmonary function and emphysema.

Dysregulated Polycomb Repressive Complex 2 contributes to chronic obstructive pulmonary disease by rewiring stem cell fate

Aberrant lung cell differentiation is a hallmark of many lung diseases including chronic obstructive pulmonary disease (COPD). The EZH2-containing Polycomb Repressive Complex 2 (PRC2) regulates embryonic lung stem cell fate, but its role in adult lung is obscure. Histological analysis of patient tissues revealed that loss of PRC2 activity was correlated with aberrant bronchiolar cell differentiation in COPD lung. Histological and single-cell RNA-sequencing analyses showed that loss of EZH2 in mouse lung organoids led to lowered self-renewal capability, increased squamous morphological development, and marked shifts in progenitor cell populations. Evaluation of in vivo models revealed that heterozygosity of Ezh2 in mice with ovalbumin-induced lung inflammation led to epithelial cell differentiation patterns similar to those in COPD lung. We also identified cystathionine-β-synthase as a possible upstream factor for PRC2 destabilization. Our findings suggest that PRC2 is integral to facilitating proper lung stem cell differentiation in humans and mice.

Loss of core-fucosylation of SPARC impairs collagen binding and contributes to COPD

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease with high morbidity and mortality worldwide. Although several mechanisms to account for deleterious immune effects were proposed, molecular description for the underlying alveolar structural alterations for COPD is lacking. Here, silencing of α1,6-fucosyltransferase (Fut8), the enzyme for core-fucosylation and highly expressed in lung stem cells, resulted in alveolar structural changes in lung organoids, recapitulating COPD. Site-specific mass spectrometry analysis demonstrated that the secreted protein acidic and rich in cysteine (SPARC), which binds collagen, contains a core-fucosylation site in its VCSNDN^cfK glycopeptide. Biacore assay showed markedly reduced collagen binding of SPARC lacking core fucosylation. Molecular dynamics analysis revealed that core fucosylation of SPARC-induced dynamic conformational changes in its N-glycan, allowing terminal galactose and N-acetylglucosamine to interact with K150, P261 and H264 residues, thereby promoting collagen binding. Site-specific mutagenesis of these residues also resulted in low affinity for collagen binding. Moreover, loss of collagen and decline of core fucosylation were observed in COPD lung tissues. These findings provide a new mechanistic insight into the role of core fucosylation of SPARC in cell–matrix communication and contribution to the abnormal alveolar structures in COPD.

Altered Differentiation and Inflammation Profiles Contribute to Enhanced Innate Responses in Severe COPD Epithelium to Rhinovirus Infection

Background

Respiratory viral infections are closely associated with COPD exacerbations, hospitalisations, and significant morbidity and mortality. The consequences of the persisting inflammation and differentiation status in virus associated severe disease is not fully understood. The aim of this study was to evaluate barrier function, cellular architecture, the inflammatory response in severe COPD bronchial epithelium to human rhinovirus (HRV) induced pathological changes and innate immune responses.

Methods

Well-differentiated primary bronchial epithelial cells (WD-PBECs) derived from severe COPD patients and age-matched healthy controls were cultured in the air-liquid interface (ALI) model. The differentiation phenotype, epithelial barrier integrity, pathological response and cytokine secreting profile of these cultures before and after HRV infection were investigated.

Results

WD-PBECs derived from severe COPD patients showed aberrant epithelium differentiation with a decreased proportion of ciliated cells but increased numbers of club cells and goblet cells compared with healthy controls. Tight junction integrity was compromised in both cultures following HRV infection, with heightened disruptions in COPD cultures. HRV induced increased epithelial cell sloughing, apoptosis and mucus hypersecretion in COPD cultures compared with healthy controls. A Th1/Th2 imbalance and a strong interferon and pro-inflammatory cytokine response was also observed in COPD cultures, characterized by increased levels of IFNγ, IFNβ, IP-10, IL-10 and decreased TSLP and IL-13 cytokine levels prior to HRV infection. Significantly enhanced basolateral secretion of eotaxin 3, IL-6, IL-8, GM-CSF were also observed in both mock and HRV infected COPD cultures compared with corresponding healthy controls. In response to HRV infection, all cultures displayed elevated levels of IFNλ1 (IL-29), IP-10 and TNFα compared with mock infected cultures. Interestingly, HRV infection dramatically reduced IFNλ levels in COPD cultures compared with healthy subjects.

Conclusion

An altered differentiation phenotype and cytokine response as seen in severe COPD WD-PBECs may contribute to increased disease susceptibility and an enhanced inflammatory response to HRV infection.

Epigenetic Mechanisms in Parenchymal Lung Diseases: Bystanders or Therapeutic Targets?

Epigenetic responses due to environmental changes alter chromatin structure, which in turn modifies the phenotype, gene expression profile, and activity of each cell type that has a role in the pathophysiology of a disease. Pulmonary diseases are one of the major causes of death in the world, including lung cancer, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH), lung tuberculosis, pulmonary embolism, and asthma. Several lines of evidence indicate that epigenetic modifications may be one of the main factors to explain the increasing incidence and prevalence of lung diseases including IPF and COPD. Interestingly, isolated fibroblasts and smooth muscle cells from patients with pulmonary diseases such as IPF and PH that were cultured ex vivo maintained the disease phenotype. The cells often show a hyper-proliferative, apoptosis-resistant phenotype with increased expression of extracellular matrix (ECM) and activated focal adhesions suggesting the presence of an epigenetically imprinted phenotype. Moreover, many abnormalities observed in molecular processes in IPF patients are shown to be epigenetically regulated, such as innate immunity, cellular senescence, and apoptotic cell death. DNA methylation, histone modification, and microRNA regulation constitute the most common epigenetic modification mechanisms.

Determinants of Pulmonary Emphysema Severity in Taiwanese Patients with Chronic Obstructive Pulmonary Disease: An Integrated Epigenomic and Air Pollutant Analysis

Background: Chronic obstructive pulmonary disease (COPD) continues to pose a therapeutic challenge. This may be connected with its nosological heterogeneity, broad symptomatology spectrum, varying disease course, and therapy response. The last three decades has been characterized by increased understanding of the pathobiology of COPD, with associated advances in diagnostic and therapeutic modalities; however, the identification of pathognomonic biomarkers that determine disease severity, affect disease course, predict clinical outcome, and inform therapeutic strategy remains a work in progress. Objectives: Hypothesizing that a multi-variable model rather than single variable model may be more pathognomonic of COPD emphysema (COPD-E), the present study explored for disease-associated determinants of disease severity, and treatment success in Taiwanese patients with COPD-E. Methods: The present single-center, prospective, non-randomized study enrolled 125 patients with COPD and 43 healthy subjects between March 2015 and February 2021. Adopting a multimodal approach, including bioinformatics-aided analyses and geospatial modeling, we performed an integrated analysis of selected epigenetic, clinicopathological, geospatial, and air pollutant variables, coupled with correlative analyses of time-phased changes in pulmonary function indices and COPD-E severity. Results: Our COPD cohort consisted of 10 non-, 57 current-, and 58 ex-smokers (median age = 69 ± 7.76 years). Based on the percentages of low attenuation area below − 950 Hounsfield units (%LAA_-950insp), 36 had mild or no emphysema (%LAA_-950insp < 6), 22 were moderate emphysema cases (6 ≤ %LAA_-950insp < 14), and 9 presented with severe emphysema (%LAA-950insp ≥ 14). We found that BMI, lnc-IL7R, PM_2.5, PM₁₀, and SO₂ were differentially associated with disease severity, and are highly-specific predictors of COPD progression. Per geospatial levels, areas with high BMI and lnc-IL7R but low PM_2.5, PM₁₀, and SO₂ were associated with fewer and ameliorated COPD cases, while high PM_2.5, PM₁₀, and SO₂ but low BMI and lnc-IL7R characterized places with more COPD cases and indicated exacerbation. The prediction pentad effectively differentiates patients with mild/no COPD from moderate/severe COPD cases, (mean AUC = 0.714) and exhibited very high stratification precision (mean AUC = 0.939). Conclusion: Combined BMI, lnc-IL7R, PM_2.5, PM₁₀, and SO₂ levels are optimal classifiers for accurate patient stratification and management triage for COPD in Taiwan. Low BMI, and lnc-IL7R, with concomitant high PM_2.5, PM₁₀, and SO₂ levels is pathognomonic of exacerbated/aggravated COPD in Taiwan.

Nutriepigenomics and chronic obstructive pulmonary disease: potential role of dietary and epigenetics factors in disease development and management

Over recent decades, a number of studies have revealed the possible role of different types of diets, as well as the nutritional elements they are made up of, in the pathogenesis of chronic obstructive pulmonary disease (COPD). To date, dietary factors have been identified to play a role in the prevention of COPD, with evidence from antioxidant nutrients, vitamins, and fiber intake. Additionally, certain dietary patterns such as the Mediterranean diet, together with other Western diets, provide evidence of the influence on COPD development, promoting lung health through nutritional approaches, and giving us an opportunity for intervention. The effect of diet on COPD is conveyed by 3 mechanisms: regulation of inflammation, oxidative stress, and carbon dioxide produced/oxygen intake. Current advances have begun to highlight the possible role of diet in modifying gene expression in certain individuals that predisposes them to COPD through epigenetic modifications. The relation between dietary intake and epigenetic factors has therefore outlined nutriepigenomics as a possible missing link in the relation between environmental exposure to smoke and the appearance of a subsequent chronic bronchial obstruction. This review summarizes the evidence regarding the influence of dietary patterns and nutrients and epigenetic regulatory mechanisms on COPD development and prevention with the aim of encouraging clinical research on the impact of dietary modifications on COPD-related clinical outcomes. This review highlights the importance of proposing and carrying out future studies focused on the modulating effects of certain nutrients on epigenetic changes in patients with specific COPD phenotypes (bronchiectasis, emphysema, asthma/COPD, chronic bronchitis), and their individual responses to cigarette smoking, environmental pollution, or other noxious particles. The objectives of these future studies must be directed to the development of novel therapeutic approaches and personalized management of COPD.

The aging lung: Physiology, disease, and immunity

The population is aging at a rate never seen before in human history. As the number of elderly adults grows, it is imperative we expand our understanding of the underpinnings of aging biology. Human lungs are composed of a unique panoply of cell types that face ongoing chemical, mechanical, biological, immunological, and xenobiotic stress over a lifetime. Yet, we do not fully appreciate the mechanistic drivers of lung aging and why age increases the risk of parenchymal lung disease, fatal respiratory infection, and primary lung cancer. Here, we review the molecular and cellular aspects of lung aging, local stress response pathways, and how the aging process predisposes to the pathogenesis of pulmonary disease. We place these insights into context of the COVID-19 pandemic and discuss how innate and adaptive immunity within the lung is altered with age.

More than a Genetic Code: Epigenetics of Lung Fibrosis

At the end of the last century, genetic studies reported that genetic information is not transmitted solely by DNA, but is also transmitted by other mechanisms, named as epigenetics. The well-described epigenetic mechanisms include DNA methylation, biochemical modifications of histones, and microRNAs. The role of altered epigenetics in the biology of various fibrotic diseases is well-established, and recent advances demonstrate its importance in the pathogenesis of pulmonary fibrosis-predominantly referring to idiopathic pulmonary fibrosis, the most lethal of the interstitial lung diseases. The deficiency in effective medications suggests an urgent need to better understand the underlying pathobiology. This review summarizes the current knowledge concerning epigenetic changes in pulmonary fibrosis and associations of these changes with several cellular pathways of known significance in its pathogenesis. It also designates the most promising substances for further research that may bring us closer to new therapeutic options.

miRNA-486-5p Promotes COPD Progression by Targeting HAT1 to Regulate the TLR4-Triggered Inflammatory Response of Alveolar Macrophages

Purpose

The aim of this study was to investigate the role of miRNA-486-5p in chronic obstructive pulmonary disease (COPD) progression and the underlying molecular mechanisms.

Materials and Methods

Aberrant miRNA expression profiles between smokers and nonsmokers, and those between COPD patients and normal subjects were analyzed using microarray datasets and reverse-transcriptase quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay was used to determine the levels of inflammatory cytokines in cell supernatants. Expression levels of inflammatory cytokines, HAT1, TLR4, and miR-486-5p, were determined using qPCR or Western blotting. Luciferase reporter assays and fluorescence in situ hybridization were used to confirm the regulatory interaction between miR-486-6p and HAT1.

Results

miR-486-5p was significantly upregulated in the COPD and smoker groups compared to the control group, as demonstrated using bioinformatics analysis and validated using qPCR assay of alveolar macrophages and peripheral monocytes. Moreover, miR-486-5p expression was significantly correlated with the expression of IL-6, IL-8, TNF-α, and IFN-γ. Luciferase reporter assays confirmed that miR-486-5p directly targeted HAT1, and cellular localization showed that miR-486-5p and HAT1 were highly expressed in the cytoplasm. miR-486-5p overexpression led to a significant upregulation of TLR4 and a significant downregulation of HAT1. Inversely, miR-486-5p inhibition led to a significant downregulation of TLR4 and a significant upregulation of HAT1. HAT1 knockdown using siRNA significantly upregulated the expression of TLR4, IL-6, IL-8, TNF-α, and IFN-γ.

Conclusion

miR-486-5p was differentially expressed in the alveolar macrophages of COPD patients. miR-486-5p overexpression may enhance the TLR4-triggered inflammatory response in COPD patients by targeting HAT1.

FN3K expression in COPD: a potential comorbidity factor for cardiovascular disease

INTRODUCTION

Cigarette smoking and oxidative stress are common risk factors for the multi-morbidities associated with chronic obstructive pulmonary disease (COPD). Elevated levels of advanced glycation endproducts (AGE) increase the risk of cardiovascular disease (CVD) comorbidity and mortality. The enzyme fructosamine-3-kinase (FN3K) reduces this risk by lowering AGE levels.

METHODS

The distribution and expression of FN3K protein in lung tissues from stable COPD and control subjects, as well as an animal model of COPD, was assessed by immunohistochemistry. Serum FN3K protein and AGE levels were assessed by ELISA in patients with COPD exacerbations receiving metformin. Genetic variants within the FN3K and FN3K-RP genes were evaluated for associations with cardiorespiratory function in the Subpopulations and Intermediate Outcome Measures in COPD Study cohort.

RESULTS

This pilot study demonstrates that FN3K expression in the blood and human lung epithelium is distributed at either high or low levels irrespective of disease status. The percentage of lung epithelial cells expressing FN3K was higher in control smokers with normal lung function, but this induction was not observed in COPD patients nor in a smoking model of COPD. The top five nominal FN3K polymorphisms with possible association to decreased cardiorespiratory function (p<0.008-0.02), all failed to reach the threshold (p<0.0028) to be considered highly significant following multi-comparison analysis. Metformin enhanced systemic levels of FN3K in COPD subjects independent of their high-expression or low-expression status.

DISCUSSION

The data highlight that low and high FN3K expressors exist within our study cohort and metformin induces FN3K levels, highlighting a potential mechanism to reduce the risk of CVD comorbidity and mortality.

Comparative proteomics analysis of patients with quick development and slow development Chronic Obstructive Pulmonary Disease (COPD)

BACKGROUND

The development of Chronic Obstructive Pulmonary Disease (COPD) has been assessed and divided into slow development (SD), normal development (ND) and quick development (QD). Little is known about the plasma proteome characters among these three phenotypes.

METHODS

We performed a comparative proteomic analysis in the plasma of normal control (NC), SD, ND and QD phenotype COPD patients using isobaric tags for relative and absolute quantitation (iTRAQ) technique.

RESULTS

A total of 683 proteins were successfully identified in the plasma samples, of which 394 were considered as high-quality proteins (95% confidential peptides ≥ 2). Further, a total of 25, 19 and 27 different abundant proteins (DAPs) were identified in SD, ND and QD groups, respectively. Gene ontology (GO) classification analysis of all DAPs showed that immune system process (GO:0002376) were the most significant. The pathway enrichment analysis showed that innate immune response (GO:0045087), receptor-mediated endocytosis (GO:0006898) and proteolysis (GO:0006508) were the branch-end terms. Notably, the 15 QD special DAPs were considered as potential markers for identify patient might have quick development COPD, and thus provided more aggressive treatment strategy for these patients.

CONCLUSION

This work provides an insight into global plasma proteome profiles among the SD, ND and QD phenotypes of COPD patients. The most significant GO terms that the DAPs enriched in were immune system related terms. In addition, the 15 QD specific DPAs provided candidates of potential markers to predict the development types of COPD patients.

Identification and Bioinformatic Analysis of Circular RNA Expression in Peripheral Blood Mononuclear Cells from Patients with Chronic Obstructive Pulmonary Disease

Purpose

Circular RNAs (circRNAs) regulate other RNA transcripts by competing for shared microRNAs, which play roles in the pathogenesis of many diseases, including chronic obstructive pulmonary disease (COPD). However, the role of circRNAs in COPD remains unknown. This study aimed to investigate the expression profile and the role of circRNAs in COPD.

Patients and Methods

Twenty-one COPD patients and twenty-one normal controls were recruited. Total RNAs were collected from peripheral blood mononuclear cells (PBMCs) of each participant. CircRNAs and protein-coding mRNAs were profiled by microarray and systematically compared between patients with COPD and control subjects. The top differentially expressed circRNAs and mRNAs were validated by quantitative real-time PCR (RT-qPCR). Functional analysis identified pathways relevant to the pathogenesis of COPD. Next, the circRNA target pathway network, the circRNA-miRNA-mRNA network (ceRNA network) and functional ceRNA regulatory modules were constructed.

Results

In total, 2132 circRNAs and 2734 protein-coding mRNAs were differentially expressed (|fold change| >1.5 and P-value <0.05) in COPD patients. Six out of nine selected RNAs were confirmed by RT-qPCR validation. Our functional analysis suggested that immune imbalances and inflammatory responses play roles in the pathogenesis of COPD. The ceRNA network highlighted the differentially expressed circRNAs and their related miRNAs and mRNAs in COPD. In the circRNA target pathway network and functional ceRNA regulatory modules, hsa_circRNA_0008672 appeared in the top three KEGG pathways (NOD-like receptor signaling pathway, natural killer cell mediated cytotoxicity and Th17 cell differentiation) and may act as the miRNA sponge regulating the hsa_circRNA_0008672/miR-1265/MAPK1 axis.

Conclusion

Our findings demonstrate critical roles of the circRNAs in COPD molecular etiology. The data support a plausible mechanism that circRNAs may be involved in the development of COPD by affecting the immune balance. Moreover, the hsa_circRNA_0008672/miR-1265/MAPK1 axis may contribute to the pathogenesis of COPD, warranting further investigation.

Flavonoids and Reduction of Cardiovascular Disease (CVD) in Chronic Obstructive Pulmonary Disease (COPD)

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) and Cardiovascular Diseases (CV) Often Coexist. COPD and CVD are complex diseases characterized by a strict interaction between environment and genetic. The mechanisms linking these two diseases are complex, multifactorial and not entirely understood, influencing the therapeutic approach. COPD is characterized by several comorbidities, it hypothesized the treatment of cardiovascular co-morbidities that may reduce morbidity and mortality. Flavonoids are an important class of plant low molecular weight Secondary Metabolites (SMs). Convincing data from laboratory, epidemiological, and human clinical studies point the important effects on CVD risk prevention.

OBJECTIVE

This review aims to provide up-to-date information on the ability of Flavonoids to reduce the CVD risk.

CONCLUSION

Current studies support the potential of Flavonoids to prevent the risk of CVD. Well-designed clinical studies are suggested to evaluate advantages and limits of Flavonoids for managing CVD comorbidity in COPD.

PRMT6 mediates inflammation via activation of the NF-κB/p65 pathway on a cigarette smoke extract-induced murine emphysema model

INTRODUCTION

Smoke-driven lung inflammation is considered to be the major pathophysiology mechanism of Chronic Obstructive Pulmonary Disease (COPD)/emphysema. Protein arginine methyltransferase 6 (PRMT6) is a key epigenetic enzyme, which is related to protecting the tri-methylation of H3K4 (H3K4me3). We hypothesized that PTMT6 protects lung inflammation through the nuclear factor kappa B (NF-κB) pathway.

METHODS

Mice were injected with cigarette smoke extract (CSE) or PBS to establish a mice model, intratracheally instilled with overexpressed PRMT6 or negative control vector. Morphometry of lung slides and lung function were measured. We determined the protein expression of PRMT6 and its related histone targets, the activation of NF-κB pathway, the level of tumor necrosis factor α (TNFα) and interleukin-1β (IL-1β).

RESULTS

After PRMT6 overexpression, the morphometry indexes and lung function were improved. Also, the expression of H3K4me3 was decreased. Overexpressed PRMT6 could suppress CSE-induced NF-κB activation and pro-inflammation genes expression.

CONCLUSIONS

The overexpressed PRMT6 could serve as an inflammation inhibitor, potentially through blocking the NF-κB/p65 pathway in the murine emphysema model.

Impact of High-Density Urban Built Environment on Chronic Obstructive Pulmonary Disease: A Case Study of Jing'an District, Shanghai

Respiratory health is a focus of interdisciplinary studies involving urban planning and public health. Studies have noted that urban built environments have impacts on respiratory health by influencing air quality and human behavior such as physical activity. The aim of this paper was to explore the impact of urban built environments on respiratory health, taking chronic obstructive pulmonary disease (COPD) as one of the typical respiratory diseases for study. A cross-sectional study was conducted including all cases (N = 1511) of death from COPD in the high-density Jing'an district of Shanghai from 2001 to 2010. Proxy variables were selected to measure modifiable features of urban built environments within this typical high-density district in Shanghai. A geographically weighted regression (GWR) model was used to explore the effects of the built environment on the mortality of COPD and the geographical variation in the effects. This study found that land use mix, building width-height ratio, frontal area density, and arterial road density were significantly correlated to the mortality of COPD in high-density urban area. By identifying built environment elements adjustable by urban planning and public policy, this study proposes corresponding environmental intervention for respiratory health.

CARM1 regulates senescence during airway epithelial cell injury in COPD pathogenesis

Chronic obstructive pulmonary disease (COPD) is a life-threatening lung disease. Although cigarette smoke was considered the main cause of development, the heterogeneous nature of the disease leaves it unclear whether other factors contribute to the predisposition or impaired regeneration response observed. Recently, epigenetic modification has emerged to be a key player in the pathogenesis of COPD. The addition of methyl groups to arginine residues in both histone and nonhistone proteins by protein arginine methyltransferases (PRMTs) is an important posttranslational epigenetic modification event regulating cellular proliferation, differentiation, apoptosis, and senescence. Here, we hypothesize that coactivator-associated arginine methyltransferase-1 (CARM1) regulates airway epithelial cell injury in COPD pathogenesis by controlling cellular senescence. Using the naphthalene (NA)-induced mouse model of airway epithelial damage, we demonstrate that loss of CC10-positive club cells is accompanied by a reduction in CARM1-expressing cells of the airway epithelium. Furthermore, Carm1 haploinsuffficent mice showed perturbed club cell regeneration following NA treatment. In addition, CARM1 reduction led to decreased numbers of antisenescent sirtuin 1-expressing cells accompanied by higher p21, p16, and β-galactosidase-positive senescent cells in the mouse airway following NA treatment. Importantly, CARM1-silenced human bronchial epithelial cells showed impaired wound healing and higher β-galactosidase activity. These results demonstrate that CARM1 contributes to airway repair and regeneration by regulating airway epithelial cell senescence.

Pharmacological Management of Chronic Obstructive Lung Disease (COPD). Focus on Mutations - Part 1

BACKGROUND

We report a comprehensive overview of current Chronic Obstructive Lung Disease (COPD) therapies and discuss the development of possible new pharmacological approaches based on "new" knowledge. Specifically, sensitivity/resistance to corticosteroids is evaluated with a special focus on the role of gene mutations in drug response.

OBJECTIVE

Critically review the opportunities and the challenges occurring in the treatment of COPD.

CONCLUSION

Findings from "omics" trials should be used to learn more about biological targeted drugs, and to select more specific drugs matching patient's distinctive molecular profile. Specific markers of inflammation such as the percentage of eosinophils are important in determining sensitivity/resistance to corticosteroids. Specific gene variations (Single nucleotide polymorphisms: SNPs) may influence drug sensitivity or resistance. Clinicians working in a real-world need to have a suitable interpretation of molecular results together with a guideline for the treatment and recommendations. Far more translational research is required before new results from omics techniques can be applied in personalized medicine in realworld settings.

Identification of Putative Regulatory Alterations Leading to Changes in Gene Expression in Chronic Obstructive Pulmonary Disease

Various genetic and environmental factors are known to be associated with chronic obstructive pulmonary disease (COPD). We identified COPD-related differentially expressed genes (DEGs) using 189 samples accompanying either adenocarcinoma (AC) or squamous cell carcinoma (SC), comprising 91 normal and 98 COPD samples. DEGs were obtained from the intersection of two DEG sets separately identified for AC and SC to exclude the influence of different cancer backgrounds co-occurring with COPD. We also measured patient samples named group 'I', which were unable to be determined as normal or COPD based on alterations in gene expression. The Gene Ontology (GO) analysis revealed significant alterations in the expression of genes categorized with the 'cell adhesion', 'inflammatory response', and 'mitochondrial functions', i.e., well-known functions related to COPD, in samples from patients with COPD. Multi-omics data were subsequently integrated to decipher the upstream regulatory changes linked to the gene expression alterations in COPD. COPD-associated expression quantitative trait loci (eQTLs) were located at the upstream regulatory regions of 96 DEGs. Additionally, 45 previously identified COPD-related miRNAs were predicted to target 66 of the DEGs. The eQTLs and miRNAs might affect the expression of 'respiratory electron transport chain' genes and 'cell proliferation' genes, respectively, while both eQTLs and miRNAs might affect the expression of 'apoptosis' genes. We think that our present study will contribute to our understanding of the molecular etiology of COPD accompanying lung cancer.

Accelerated lung aging and chronic obstructive pulmonary disease

INTRODUCTION

The prevalence of chronic obstructive pulmonary disease (COPD) increases exponentially with aging. Its pathogenesis, however, is not well known and aside from smoking cessation, there are no disease-modifying treatments for this disease. Areas covered: COPD is associated with accelerating aging and aging-related diseases. In this review, we will discuss the hallmarks of aging including genomic instability, telomere attrition, epigenetic alteration, loss of proteostasis, mitochondrial dysfunction, deregulated nutrient sensing, cellular senescence, stem cell exhaustion, and altered intercellular communication, which may be involved in COPD pathogenesis. Expert commentary: COPD and the aging process share similar molecular and cellular changes. Aging-related molecular pathways may represent novel therapeutic targets and biomarkers for COPD.

Pharmacological Management of Chronic Obstructive Lung Disease (COPD). Evidence from a Real-World Perspective - Part 2

BACKGROUND

We report a comprehensive overview of current COPD therapies from a real-world experience.

OBJECTIVE

Critically review the opportunities and the challenges occurring in the real-world treatment of COPD.

METHODS

This is a review that also report results from COPD patients treated with standardized therapy including pulmonary rehabilitation (Real World Data - RWD).

CONCLUSION

Comprehensive assessment of COPD management requires strategies able to evaluate efficacy and usefulness in a real-world population, that take into account the interaction between experience and academic training, research, adherence to guidelines and judgments in order to plan the appropriate and optimum use of available strategies.

miRNA-206 regulates human pulmonary microvascular endothelial cell apoptosis via targeting in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death due to tis high morbidity and mortality. microRNAs have emerged as new biomarkers for the prognosis and diagnosis of patients with COPD. In this study, we aimed to investigate the expression of microRNA-206 (miR-206) in lung tissues from COPD patients and to explore the regulatory role of miR-206 in the human pulmonary microvascular endothelial cells (HPMECs). Our results showed that cigarette smoke extract (CSE) promoted cell apoptosis, increased caspase-3 activity, and upregulated the expression of miR-206 in HPMECs, which was significantly reversed by the miR-206 knockdown. Transfection with miR-206 mimics led to cell apoptosis and was closely related to changes in the protein expression levels of caspase-3, caspase-9, and Bcl-2 in HPMECs. Further bioinformatics prediction analysis revealed that the 3'-untranslated region (3'UTR) of Notch3 and vascular endothelial growth factor-A (VEGFA) harbored miR-206-binding sites, and overexpression of miR-206 repressed the luciferase activity of the vectors containing Notch3 and VEGFA 3'UTR. Overexpression of either Notch3 or VEGFA attenuated miR-206-induced cell apoptosis in HPMECs. More importantly, miR-206 expression was upregulated in the lung tissues from COPD patients and was positively corrected with forced expiratory volume 1% predicted in COPD patients, while Notch3 and VEGFA mRNA levels were downregulated and were negatively correlated with the expression level of miR-206 in the lung tissues from COPD patients. In conclusion, our results showed that miR-206 was upregulated in COPD patients and CSE-treated HPMECs, promoted cell apoptosis via directly targeting Notch3 and VEGFA in HPMECs.

Upregulation of miR-132 contributes to the pathophysiology of COPD via targeting SOCS5

The role of microRNAs has been recently identified in chronic obstructive pulmonary disease (COPD). This study aimed to examine the role of miR-132 in the pathophysiology of COPD and to explore the underlying molecular mechanisms of miR-132 in COPD. MiR-132 and suppressor of cytokine signaling 5 (SOCS5) mRNA expression were detected by qRT-PCR. The number of CD4⁺ and CD8⁺ T cells was analyzed by flow cytometry. SOCS5 and epidermal growth factor receptor (EGFR) protein levels were determined by western blot. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations were measured by ELISA. MiR-132 expression was up-regulated in the serum from COPD patients and smokers compared with nonsmoker controls. The number of CD8⁺ T cells was significantly increased in the serum from COPD patients and smokers. MiR-132 expression was negatively correlated with FEV₁/FVC%, and positively correlated with CD8⁺ T cells (%). MiR-132 overexpression repressed SOCS5 expression via directly targeting SOCS5 3'UTR in human monocyte-like cells (THP-1), which was confirmed by luciferase reporter assay. MiR-132 overexpression increased EGFR protein levels and the concentrations of inflammatory cytokines (IL-1β and TNF-α) in THP-1 cells, and these effects were attenuated by enforced expression of SOCS5. Further, cigarette smoke extract (CSE) treatment up-regulated miR-132 expression, down-regulated SOCS5 expression, and increased inflammatory cytokines levels, which was attenuated by miR-132 knockdown in THP-1 cells. Consistent findings were also found in the human bronchial epithelial cells (BEAS-2B). Collectively, our data implicated that miR-132 may promote inflammation in THP-1 and BEAS-2B cells at least via targeting SOCS5 in COPD.

Pulmonary rehabilitation and BDNF levels in patients with chronic obstructive pulmonary disease: A pilot study

BACKGROUND

COPD physiopathology involves multiple pathways and evidence indicates that brain-derived neurotrophic factor (BDNF) is an important biomarker associated with parameters of COPD severity. This study aimed to analyze the time course of the effects of a pulmonary rehabilitation program (PRP) on BDNF levels and on functional status in COPD patients.

METHODS

Patients were enrolled in a 24-session PRP. Exercise capacity, dyspnea, health-related quality of life, and the BODE index were assessed at baseline and after the PRP. BDNF plasma levels were measured at baseline (immediately before the 1^st session), after the 1^st session, and before and after the 24^th session.

RESULTS

Sixteen patients were included. A reduction in BDNF levels was observed after the 1^st session and an increase was observed between the end of the 1^st session and the beginning of the 24^th session. The PRP promoted an improvement in exercise capacity and health-related quality of life and a reduction in dyspnea and the BODE index.

CONCLUSION

Exercise acutely reduced BDNF levels, an effect that was nullified by the overall intervention.

Sputum proteomics and airway cell transcripts of current and ex-smokers with severe asthma in U-BIOPRED: an exploratory analysis

Severe asthma patients with a significant smoking history have airflow obstruction with reported neutrophilia. We hypothesise that multi-omic analysis will enable the definition of smoking and ex-smoking severe asthma molecular phenotypes.The U-BIOPRED cohort of severe asthma patients, containing current-smokers (CSA), ex-smokers (ESA), nonsmokers and healthy nonsmokers was examined. Blood and sputum cell counts, fractional exhaled nitric oxide and spirometry were obtained. Exploratory proteomic analysis of sputum supernatants and transcriptomic analysis of bronchial brushings, biopsies and sputum cells was performed.Colony-stimulating factor (CSF)2 protein levels were increased in CSA sputum supernatants, with azurocidin 1, neutrophil elastase and CXCL8 upregulated in ESA. Phagocytosis and innate immune pathways were associated with neutrophilic inflammation in ESA. Gene set variation analysis of bronchial epithelial cell transcriptome from CSA showed enrichment of xenobiotic metabolism, oxidative stress and endoplasmic reticulum stress compared to other groups. CXCL5 and matrix metallopeptidase 12 genes were upregulated in ESA and the epithelial protective genes, mucin 2 and cystatin SN, were downregulated.Despite little difference in clinical characteristics, CSA were distinguishable from ESA subjects at the sputum proteomic level, with CSA patients having increased CSF2 expression and ESA patients showing sustained loss of epithelial barrier processes.

The potential for targeted rewriting of epigenetic marks in COPD as a new therapeutic approach

Chronic obstructive pulmonary disease (COPD) is an age and smoking related progressive, pulmonary disorder presenting with poorly reversible airflow limitation as a result of chronic bronchitis and emphysema. The prevalence, disease burden for the individual, and mortality of COPD continues to increase, whereas no effective treatment strategies are available. For many years now, a combination of bronchodilators and anti-inflammatory corticosteroids has been most widely used for therapeutic management of patients with persistent COPD. However, this approach has had disappointing results as a large number of COPD patients are corticosteroid resistant. In patients with COPD, there is emerging evidence showing aberrant expression of epigenetic marks such as DNA methylation, histone modifications and microRNAs in blood, sputum and lung tissue. Therefore, novel therapeutic approaches may exist using epigenetic therapy. This review aims to describe and summarize current knowledge of aberrant expression of epigenetic marks in COPD. In addition, tools available for restoration of epigenetic marks are described, as well as delivery mechanisms of epigenetic editors to cells. Targeting epigenetic marks might be a very promising tool for treatment and lung regeneration in COPD in the future.

The EGFR-ADAM17 Axis in Chronic Obstructive Pulmonary Disease and Cystic Fibrosis Lung Pathology

Chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF) share molecular mechanisms that cause the pathological symptoms they have in common. Here, we review evidence suggesting that hyperactivity of the EGFR/ADAM17 axis plays a role in the development of chronic lung disease in both CF and COPD. The ubiquitous transmembrane protease A disintegrin and metalloprotease 17 (ADAM17) forms a functional unit with the EGF receptor (EGFR), in a feedback loop interaction labeled the ADAM17/EGFR axis. In airway epithelial cells, ADAM17 sheds multiple soluble signaling proteins by proteolysis, including EGFR ligands such as amphiregulin (AREG), and proinflammatory mediators such as the interleukin 6 coreceptor (IL-6R). This activity can be enhanced by injury, toxins, and receptor-mediated external triggers. In addition to intracellular kinases, the extracellular glutathione-dependent redox potential controls ADAM17 shedding. Thus, the epithelial ADAM17/EGFR axis serves as a receptor of incoming luminal stress signals, relaying these to neighboring and underlying cells, which plays an important role in the resolution of lung injury and inflammation. We review evidence that congenital CFTR deficiency in CF and reduced CFTR activity in chronic COPD may cause enhanced ADAM17/EGFR signaling through a defect in glutathione secretion. In future studies, these complex interactions and the options for pharmaceutical interventions will be further investigated.

The Intersection of Aging Biology and the Pathobiology of Lung Diseases: A Joint NHLBI/NIA Workshop

Death from chronic lung disease is increasing and chronic obstructive pulmonary disease has become the third leading cause of death in the United States in the past decade. Both chronic and acute lung diseases disproportionately affect elderly individuals, making it likely that these diseases will become more frequent and severe as the worldwide population ages. Chronic lung diseases are associated with substantial morbidity, frequently resulting in exercise limiting dyspnea, immobilization, and isolation. Therefore, effective strategies to prevent or treat lung disease are likely to increase healthspan as well as life span. This review summarizes the findings of a joint workshop sponsored by the NIA and NHLBI that brought together investigators focused on aging and lung biology. These investigators encouraged the use of genetic systems and aged animals in the study of lung disease and the development of integrative systems-based platforms that can dynamically incorporate data sets that describe the genomics, transcriptomics, epigenomics, metabolomics, and proteomics of the aging lung in health and disease. Further research was recommended to integrate benchmark biological hallmarks of aging in the lung with the pathobiology of acute and chronic lung diseases with divergent pathologies for which advanced age is the most important risk factor.

Cigarette smoke and decreased oxygen tension inhibit pulmonary claudin-6 expression

PURPOSE

Chronic obstructive pulmonary disease is a condition involving perturbed barrier integrity coincident with both emphysema and inflammation of the airways, and smoking is considered a major risk factor. Claudins (Cldns) stabilize barriers and contribute to tight junctions by preventing paracellular transport of extracellular fluid constituents.

METHODS

To determine Cldn6 was differentially influenced by tobacco smoke, Cldn6 was evaluated in cells and tissues by q-PCR, immunoblotting, and immunohistochemistry following exposure. Cldn6 transcriptional regulation was also assessed using luciferase reporter constructs.

RESULTS

Q-PCR and immunoblotting revealed that Cldn6 was decreased in alveolar type II-like epithelial cells (A549) and primary small airway epithelial cells when exposed to cigarette smoke extract (CSE). Cldn6 was also markedly decreased in the lungs of mice exposed to acute tobacco smoke delivered by a nose-only automated smoke machine compared to controls. Luciferase reporter assays incorporating 0.5-kb, 1.0-kb, or 2.0-kb of the Cldn6 promoter revealed decreased transcription of Cldn6 following exposure to CSE. Cldn6 transcriptional regulation was also assessed in hypoxic conditions due to low oxygen tension observed during smoking. Hypoxia and hypoxia inducible factor-1 alpha caused decreased transcription of the Cldn6 gene via interactions with putative response elements in the proximal promoter sequence.

CONCLUSIONS

These data reveal that tight junctional proteins such as Cldn6 are differentially regulated by tobacco-smoke exposure and that Cldns are potentially targeted when epithelial cells respond to tobacco smoke. Further research may show that Cldns expressed in tight junctions between parenchymal cells contribute to impaired structural integrity of the lung coincident with smoking.

Functional AdoMet Isosteres Resistant to Classical AdoMet Degradation Pathways

S-adenosyl-l-methionine (AdoMet) is an essential enzyme cosubstrate in fundamental biology with an expanding range of biocatalytic and therapeutic applications. We report the design, synthesis, and evaluation of stable, functional AdoMet isosteres that are resistant to the primary contributors to AdoMet degradation (depurination, intramolecular cyclization, and sulfonium epimerization). Corresponding biochemical and structural studies demonstrate the AdoMet surrogates to serve as competent enzyme cosubstrates and to bind a prototypical class I model methyltransferase (DnrK) in a manner nearly identical to AdoMet. Given this conservation in function and molecular recognition, the isosteres presented are anticipated to serve as useful surrogates in other AdoMet-dependent processes and may also be resistant to, and/or potentially even inhibit, other therapeutically relevant AdoMet-dependent metabolic transformations (such as the validated drug target AdoMet decarboxylase). This work also highlights the ability of the prototypical class I model methyltransferase DnrK to accept non-native surrogate acceptors as an enabling feature of a new high-throughput methyltransferase assay.

Early injury of the neonatal lung contributes to premature lung aging: a hypothesis

Chronic lung disease of the newborn, also known as bronchopulmonary dysplasia (BPD), is the most common chronic lung disease in early infancy and results in an increased risk for long-lasting pulmonary impairment in the adult. BPD develops upon injury of the immature lung by oxygen toxicity, mechanical ventilation, and infections which trigger sustained inflammatory immune responses and extensive remodeling of the extracellular matrix together with dysregulated growth factor signaling. Histopathologically, BPD is characterized by impaired alveolarization, disrupted vascular development, and saccular wall fibrosis. Here, we explore the hypothesis that development of BPD involves disturbance of conserved pathways of molecular aging that may contribute to premature aging of the lung and an increased susceptibility to chronic lung diseases in adulthood.

Bronchial epithelial cells: The key effector cells in the pathogenesis of chronic obstructive pulmonary disease?

The primary function of the bronchial epithelium is to act as a defensive barrier aiding the maintenance of normal airway function. Bronchial epithelial cells (BEC) form the interface between the external environment and the internal milieu, making it a major target of inhaled insults. However, BEC can also serve as effectors to initiate and orchestrate immune and inflammatory responses by releasing chemokines and cytokines, which recruit and activate inflammatory cells. They also produce excess reactive oxygen species as a result of an oxidant/antioxidant imbalance that contributes to chronic pulmonary inflammation and lung tissue damage. Accumulated mucus from hyperplastic BEC obstructs the lumen of small airways, whereas impaired cell repair, squamous metaplasia and increased extracellular matrix deposition underlying the epithelium is associated with airway remodelling particularly fibrosis and thickening of the airway wall. These alterations in small airway structure lead to airflow limitation, which is critical in the clinical diagnosis of chronic obstructive pulmonary disease (COPD). In this review, we discuss the abnormal function of BEC within a disturbed immune homeostatic environment consisting of ongoing inflammation, oxidative stress and small airway obstruction. We provide an overview of recent insights into the function of the bronchial epithelium in the pathogenesis of COPD and how this may provide novel therapeutic approaches for a number of chronic lung diseases.