Unravelling the complexity of COPD by microRNAs: it's a small world after all

MicroRNAs: Key modulators of inflammation-associated diseases

Inflammation is a multifaceted biological and pathophysiological response to injuries, infections, toxins, and inflammatory mechanisms that plays a central role in the progression of various diseases. MicroRNAs (miRNAs) are tiny, 19-25 nucleotides long, non-coding RNAs that regulate gene expression via post-transcriptional repression. In this review, we highlight the recent findings related to the significant roles of miRNAs in regulating various inflammatory cascades and immunological processes in the context of many lifestyle-related diseases such as diabetes, cardiovascular diseases, cancer, etc. We also converse on how miRNAs can have a dual impact on inflammatory responses, suggesting that regulation of their functions for therapeutic purposes may be disease-specific.

PTD-FGF2 Attenuates Elastase Induced Emphysema in Mice and Alveolar Epithelial Cell Injury

Aberrant communication in alveolar epithelium is a major feature of inflammatory response for the airway remodeling leading to chronic obstructive pulmonary disease (COPD). In this study, we investigated the effect of protein transduction domains (PTD) conjugated Basic Fibroblast Growth Factor (FGF2) (PTD-FGF2) in response to cigarette smoke extract (CSE) in MLE-12 cells and porcine pancreatic elastase (PPE)-induced emphysematous mice. When PPE-induced mice were intraperitoneally treated with 0.1-0.5 mg/kg PTD-FGF2 or FGF2, the linear intercept, infiltration of inflammatory cells into alveoli and pro-inflammatory cytokines were significantly decreased. In western blot analysis, phosphorylated protein levels of c-Jun N-terminal Kinase 1/2 (JNK1/2), extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein kinases (MAPK) were decreased in PPE-induced mice treated PTD-FGF2. In MLE-12 cells, PTD-FGF2 treatment decreased reactive oxygen species (ROS) production and further decreased Interleukin-6 (IL-6) and IL-1b cytokines in response to CSE. In addition, phosphorylated protein levels of ERK1/2, JNK1/2 and p38 MAPK were reduced. We next determined microRNA expression in the isolated exosomes of MLE-12 cells. In reverse transcription-polymerase chain reaction (RT-PCR) analysis, level of let-7c miRNA was significantly increased while levels of miR-9 and miR-155 were decreased in response to CSE. These data suggest that PTD-FGF2 treatment plays a protective role in regulation of let-7c, miR-9 and miR-155 miRNA expressions and MAPK signaling pathways in CSE-induced MLE-12 cells and PPE-induced emphysematous mice.

Integrative genetic and genomic networks identify microRNA associated with COPD and ILD

Chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) are clinically and molecularly heterogeneous diseases. We utilized clustering and integrative network analyses to elucidate roles for microRNAs (miRNAs) and miRNA isoforms (isomiRs) in COPD and ILD pathogenesis. Short RNA sequencing was performed on 351 lung tissue samples of COPD (n = 145), ILD (n = 144) and controls (n = 64). Five distinct subclusters of samples were identified including 1 COPD-predominant cluster and 2 ILD-predominant clusters which associated with different clinical measurements of disease severity. Utilizing 262 samples with gene expression and SNP microarrays, we built disease-specific genetic and expression networks to predict key miRNA regulators of gene expression. Members of miR-449/34 family, known to promote airway differentiation by repressing the Notch pathway, were among the top connected miRNAs in both COPD and ILD networks. Genes associated with miR-449/34 members in the disease networks were enriched among genes that increase in expression with airway differentiation at an air-liquid interface. A highly expressed isomiR containing a novel seed sequence was identified at the miR-34c-5p locus. 47% of the anticorrelated predicted targets for this isomiR were distinct from the canonical seed sequence for miR-34c-5p. Overexpression of the canonical miR-34c-5p and the miR-34c-5p isomiR with an alternative seed sequence down-regulated NOTCH1 and NOTCH4. However, only overexpression of the isomiR down-regulated genes involved in Ras signaling such as CRKL and GRB2. Overall, these findings elucidate molecular heterogeneity inherent across COPD and ILD patients and further suggest roles for miR-34c in regulating disease-associated gene-expression.

miR-223: a key regulator of pulmonary inflammation

Small noncoding RNAs, known as microRNAs (miRNAs), are vital for the regulation of diverse biological processes. miR-223, an evolutionarily conserved anti-inflammatory miRNA expressed in cells of the myeloid lineage, has been implicated in the regulation of monocyte-macrophage differentiation, proinflammatory responses, and the recruitment of neutrophils. The biological functions of this gene are regulated by its expression levels in cells or tissues. In this review, we first outline the regulatory role of miR-223 in granulocytes, macrophages, endothelial cells, epithelial cells and dendritic cells (DCs). Then, we summarize the possible role of miR-223 in chronic obstructive pulmonary disease (COPD), acute lung injury (ALI), coronavirus disease 2019 (COVID-19) and other pulmonary inflammatory diseases to better understand the molecular regulatory networks in pulmonary inflammatory diseases.

CIRC_0026466 KNOCKDOWN PROTECTS HUMAN BRONCHIAL EPITHELIAL CELLS FROM CIGARETTE SMOKE EXTRACT-INDUCED INJURY BY PROMOTING THE MIR-153-3P/TRAF6/NF-ΚB PATHWAY

ABSTRACT

Background: Considerable data have shown that circular RNAs (circRNAs) mediate the pathogenesis of chronic obstructive pulmonary disease (COPD). The study aims to analyze the function and mechanism of circ_0026466 in COPD. Methods: Human bronchial epithelial cells (16HBE) were treated with cigarette smoke extract (CSE) to establish a COPD cell model. Quantitative real-time polymerase chain reaction and Western blot were used to detect the expression of circ_0026466, microRNA-153-3p (miR-153-3p), TNF receptor associated factor 6 (TRAF6), cell apoptosis-related proteins, and NF-κB pathway-related proteins. Cell viability, proliferation, apoptosis, and inflammation were investigated by cell counting kit-8, EdU assay, flow cytometry, and enzyme-linked immunosorbent assay, respectively. Oxidative stress was evaluated by lipid peroxidation malondialdehyde assay kit and superoxide dismutase activity assay kit. The interaction between miR-153-3p and circ_0026466 or TRAF6 was confirmed by dual-luciferase reporter assay and RNA pull-down assay. Results: Circ_0026466 and TRAF6 expression were significantly increased, but miR-153-3p was decreased in the blood samples of smokers with COPD and CSE-induced 16HBE cells when compared with controls. CSE treatment inhibited the viability and proliferation of 16HBE cells but induced cell apoptosis, inflammation, and oxidative stress, but these effects were attenuated after circ_0026466 knockdown. Circ_0026466 interacted with miR-153-3p and regulated CSE-caused 16HBE cell damage by targeting miR-153-3p. Additionally, TRAF6, a target gene of miR-153-3p, regulated CSE-induced 16HBE cell injury by combining with miR-153-3p. Importantly, circ_0026466 activated NF-κB pathway by targeting the miR-153-3p/TRAF6 axis. Conclusion: Circ_0026466 absence protected against CSE-triggered 16HBE cell injury by activating the miR-153-3p/TRAF6/NF-κB pathway, providing a potential therapeutic target for COPD.

microRNA-149-5p mediates the PM2.5-induced inflammatory response by targeting TAB2 via MAPK and NF-κB signaling pathways in vivo and in vitro

Epidemiological evidence has shown that fine particulate matter (PM2.5)-triggered inflammatory cascades are pivotal causes of chronic obstructive pulmonary disease (COPD). However, the specific molecular mechanism involved in PM2.5-induced COPD has not been clarified. Herein, we found that PM2.5 significantly downregulated miR-149-5p and activated the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways and generated the inflammatory response in COPD mice and in human bronchial epithelial (BEAS-2B) cells. We determined that increased expression of interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) induced by PM2.5 was associated with decreased expression of miR-149-5p. The loss- and gain-of-function approach further confirmed that miR-149-5p could inhibit PM2.5-induced cell inflammation in BEAS-2B cells. The double luciferase reporter assay showed that miR-149-5p directly targeted TGF-beta-activated kinase 1 binding protein 2 (TAB2), which regulates the MAPK and NF-κB signaling pathways. We showed that miR-149-5p mediated the inflammatory response by targeting the 3'-UTR sequence of TAB2 and that it subsequently weakened the TAB2 promotor effect via the MAPK and NF-κB signaling pathways in BEAS-2B cells exposed to PM2.5. Thus, miR-149-5p may be a key factor in PM2.5-induced COPD. This study improves our understanding of the molecular mechanism of COPD.

Main Pathogenic Mechanisms and Recent Advances in COPD Peripheral Skeletal Muscle Wasting

Chronic obstructive pulmonary disease (COPD) is a worldwide prevalent respiratory disease mainly caused by tobacco smoke exposure. COPD is now considered as a systemic disease with several comorbidities. Among them, skeletal muscle dysfunction affects around 20% of COPD patients and is associated with higher morbidity and mortality. Although the histological alterations are well characterized, including myofiber atrophy, a decreased proportion of slow-twitch myofibers, and a decreased capillarization and oxidative phosphorylation capacity, the molecular basis for muscle atrophy is complex and remains partly unknown. Major difficulties lie in patient heterogeneity, accessing patients' samples, and complex multifactorial process including extrinsic mechanisms, such as tobacco smoke or disuse, and intrinsic mechanisms, such as oxidative stress, hypoxia, or systemic inflammation. Muscle wasting is also a highly dynamic process whose investigation is hampered by the differential protein regulation according to the stage of atrophy. In this review, we report and discuss recent data regarding the molecular alterations in COPD leading to impaired muscle mass, including inflammation, hypoxia and hypercapnia, mitochondrial dysfunction, diverse metabolic changes such as oxidative and nitrosative stress and genetic and epigenetic modifications, all leading to an impaired anabolic/catabolic balance in the myocyte. We recapitulate data concerning skeletal muscle dysfunction obtained in the different rodent models of COPD. Finally, we propose several pathways that should be investigated in COPD skeletal muscle dysfunction in the future.

Comparison of effects of tobacco cigarettes, electronic nicotine delivery systems and tobacco heating products on miRNA-mediated gene expression. A systematic review

OBJECTIVES

This work attempts to summarize current knowledge on the effects of cigarettes, electronic nicotine delivery systems and tobacco heating products on miRNA-mediated gene expression regulation and on their possible impact on smoking-related respiratory disease development.

MATERIALS AND METHODS

Literature search by terms combination: 'smoking', 'cigarette' 'THP', 'tobacco heating product', 'ENDS', 'electronic nicotine delivery system', 'e-cigarette', electronic cigarette' and 'miRNA-mediated gene expression' has been performed from October 2021 to February 2022. In this systematic review all relevant literature, including clinical trials, cellular and animal-based studies were included.

RESULTS

Cigarette smoke (CS) significantly altered transcriptome, including miRNAs expression profile. MiRNA-mediated gene expression is mentioned as one of the mechanisms associated with smoking-related respiratory disease development. Differential expression of miRNAs was reduced in aerosol from e-cigarettes (EC) and tobacco heating products (THP) when compared to CS. However, there was a significant alteration of some miRNAs expression when compared to air-controls in both EC and THP.

DISCUSSION

CS negatively affects transcriptome and miRNA-mediated gene expression regulation because of a huge number of hazardous substances which predispose to smoking-related diseases. Despite the reduced effect of ENDS and THP on miRNAs profile compared to CS, differences in expression of miRNAs when compared to air-control were observed, which may be harmful to never-smokers who may perceive such alternative smoking products as non-hazardous. To clearly indicate the role of ENDS and THP in the alteration of miRNA-mediated gene expression and the development of smoking-related respiratory diseases associated with this mechanism, more long-term studies should be performed in the future.

Transcription Factor p300 Regulated miR-451b Weakens the Cigarette Smoke Extract-Induced Cellular Stress by Targeting RhoA/ROCK2 Signaling

Background

A previous study identified miR-451b as a potential biomarker in smoker with or without chronic obstructive pulmonary disease (COPD). However, the function and molecular mechanisms of miR-451b in the pathogenesis of COPD remain elusive.

Methods

Macrophages and lung fibroblasts were exposed to 10% cigarette smoke extract (CSE) solution for 24 h. Expression miR-451b and its potential transcription factor p300 were detected. The association between p300 and miR-451b, miR-451b and RhoA was validated by luciferase reporter assay. The release of IL-12 and TNF-αby macrophages was measured by ELISA assay, and Transwell assay was performed to analyze its migration and invasion. Collagen protein of fibroblasts was detected by Western blotting.

Results

Results showed that p300 and miR-451b was downregulated, while RhoA was upregulated in CSE-induced macrophages and lung fibroblasts. The stimulation of CSE promoted the degradation of p300 by ubiquitination, and RhoA was confirmed as the target gene of miR-451b. MiR-451b overexpression significantly decreased the release of IL-12 and TNF-α, downregulated the expression of RhoA, ROCK2, and p65, and suppressed cell migration and invasion in CES-induced macrophages. In addition, miR-451b overexpression decreased the expression of RhoA, ROCK2, COL1A1, and COL2A1 in lung fibroblasts.

Conclusions

Our data suggest that p300/miR-451b protects against CSE-induced cell stress possibly through downregulating RhoA/ROCK2 pathway.

COPD and Gut–Lung Axis: How Microbiota and Host Inflammasome Influence COPD and Related Therapeutics

The exact pathogenesis of chronic obstructive pulmonary disease (COPD) remains largely unknown. While current management strategies are effective at stabilizing the disease or relief the symptoms, new approaches are required to target underlying disease process and reverse lung function deterioration. Recent research showed that pneumonia bacteria is critical in disease progression and gut microbiome is likely perturbed in COPD, which is usually accompanied by a decreased intestinal microbial diversity and a disturbance in immune system, contributing to a chronic inflammation. The cross-talk between gut microbes and lungs, termed as the “gut-lung axis,” is known to impact immune response and homeostasis in the airway. Although the gut and respiratory microbiota exhibit compositional differences, the gut and lung showed similarities in the origin of epithelia of both gastrointestinal and respiratory tracts, the anatomical structure, and early-life microbial colonization. Evidence showed that respiratory infection might be prevented, or at least dampened by regulating gut microbial ecosystem; thus, a promising yet understudied area of COPD management is nutrition-based preventive strategies. COPD patient is often deficient in nutrient such as antioxidant, vitamins, and fiber intake. However, further larger-scale randomized clinical trials (RCTs) are required to establish the role of these nutrition-based diet in COPD management. In this review, we highlight the important and complex interaction of microbiota and immune response on gut-lung axis. Further research into the modification and improvement of the gut microbiota and new interventions through diet, probiotics, vitamins, and fecal microbiota transplantation is extreme critical to provide new preventive therapies for COPD.

Hsa-Mir-320c, Hsa-Mir-200c-3p, and Hsa-Mir-449c-5p as Potential Specific miRNA Biomarkers of COPD: A Pilot Study

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease commonly induced by cigarette smoke. The expression of miRNAs can be altered in patients with COPD and could be used as a biomarker. We aimed to identify a panel of miRNAs in bronchoalveolar lavage (BAL) to differentiate COPD patients from smokers and non-smokers with normal lung function. Accordingly, forty-five subjects classified as COPD, smokers, and non-smokers (n = 15 per group) underwent clinical, functional characterization and bronchoscopy with BAL. The mean age of the studied population was 61.61 ± 12.95 years, BMI 25.72 ± 3.82 Kg/m², FEV1/FVC 68.37 ± 12.00%, and FEV1 80.07 ± 23.63% predicted. According to microarray analysis, three miRNAs of the most upregulated were chosen: miR-320c, miR-200c-3p, and miR-449c-5p. These miRNAs were validated by qPCR and were shown to be differently expressed in COPD patients. ROC analysis showed that these three miRNAs together had an area under the curve of 0.89 in differentiating COPD from controls. Moreover, in silico analysis of candidate miRNAs by DIANA-miRPath showed potential involvement in the EGFR and Hippo pathways. These results suggest a specific 3-miRNA signature that could be potentially used as a biomarker to distinguish COPD patients from smokers and non-smoker subjects.

The role of microRNAs in COVID-19 with a focus on miR-200c

Objective:

Epigenetics is a quickly spreading scientific field, and the study of epigenetic regulation in various diseases such as infectious diseases is emerging. The microribonucleic acids (miRNAs) as one of the types of epigenetic processes bind to their target messenger RNAs (mRNAs) and regulate their stability and/or translation. This study aims to evaluate non-coding RNAs (ncRNAs) with a focus on miR-200c in COVID-19. In this review, we first define the epigenetics and miRNAs, and then the role of miRNAs in diseases focusing on lung diseases is explained. Finally, in this study, we will investigate the role and position of miRNAs with a focus on miR-200c in viral and severe acute respiratory syndrome–related coronavirus (SARS-CoV2) infections.

Methods:

Systematic search of MEDLINE, PubMed, Web of Science, Embase, and Cochrane Library was conducted for all relative papers from 2000 to 2021 with the limitations of the English language. Finally, we selected 128 articles which fit the best to our objective of study, among which 5 articles focused on the impact of miR-200c.

Results:

Due to the therapeutic results of various drugs in different races and populations, epigenetic processes, especially miRNAs, are important. The overall results showed that different types of miRNAs can be effective on the process of various lung diseases through different target pathways and genes. It is likely that amplified levels of miR-200c may lead to decreased angiotensin-converting enzyme-2 (ACE2) expression, which in turn may increase the potential of infection, inflammation, and the complications of coronavirus disease.

Conclusion:

miR-200c and its correlation with ACE2 can be used as early prognostic and diagnostic markers.

Emerging noncoding RNAs contained in extracellular vesicles: rising stars as biomarkers in lung cancer liquid biopsy

Lung cancer has a high morbidity and mortality rate, and affected patients have a poor prognosis and low survival. The therapeutic approaches for lung cancer treatment, including surgery, radiotherapy, and chemotherapy, are not completely effective, due to late diagnosis. Although the identification of genetic drivers has contributed to the improvement of lung cancer clinical management, the discovery of new diagnostic and prognostic tools remains a critical issue. Liquid biopsy (LB) represents a minimally invasive approach and practical alternative source to investigate tumor-derived alterations and to facilitate the selection of targeted therapies. LB allows for the testing of different analytes such as circulating tumor cells, extracellular vesicles (EVs), tumor-educated platelets, and cell-free nucleic acids including DNAs, RNAs, and noncoding RNAs (ncRNAs). Several regulatory factors control the key cellular oncogenic pathways involved in cancers. ncRNAs have a wide range of regulatory effects in lung cancers. This review focuses on emerging regulatory ncRNAs, freely circulating in body fluids or shuttled by EVs, such as circular-RNAs, small nucleolar-RNAs, small nuclear-RNAs, and piwi-RNAs, as new biomarkers for early detection, prognosis, and monitoring of therapeutic strategy of lung cancer treatment.

A decline in club cell secretory proteins in lung transplantation is associated with release of natural killer cells exosomes leading to chronic rejection

BACKGROUND

In human lung transplant recipients, a decline in club cell secretory protein (CCSP) in bronchoalveolar lavage fluid has been associated with chronic lung allograft dysfunction (CLAD) as well as the induction of exosomes and immune responses that lead to CLAD. However, the mechanisms by which CCSP decline contributes to CLAD remain unknown.

METHODS

To define the mechanisms leading to CCSP decline and chronic rejection, we employed two mouse models: 1) chronic rejection after orthotopic single lung transplantation and 2) anti-major histocompatibility complex (MHC) class I-induced obliterative airway disease.

RESULTS

In the chronic rejection mouse model, we detected circulating exosomes with donor MHC (H2b) and lung self-antigens and also development of antibodies to H2b and lung self-antigens and then a decline in CCSP. Furthermore, DBA2 mice that received injections of these exosomes developed antibodies to donor MHC and lung self-antigens. In the chronic rejection mouse model, natural killer (NK) and CD8 T cells were the predominant graft-infiltrating cells on day 14 of rejection followed by exosomes containing NK cell-associated and cytotoxic molecules on day 14 and 28. When NK cells were depleted, exosomes with NK cell-associated and cytotoxic molecules as well as fibrosis decreased.

CONCLUSIONS

Induction of exosomes led to immune responses to donor MHC and lung self-antigens, resulting in CCSP decline, leading to NK cell infiltration and release of exosomes from NK cells. These results suggest a novel role for exosomes derived from NK cells in the pathogenesis of chronic lung allograft rejection.

Distinct Exosomal miRNA Profiles from BALF and Lung Tissue of COPD and IPF Patients

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic, progressive lung ailments that are characterized by distinct pathologies. Early detection biomarkers and disease mechanisms for these debilitating diseases are lacking. Extracellular vesicles (EVs), including exosomes, are small, lipid-bound vesicles attributed to carry proteins, lipids, and RNA molecules to facilitate cell-to-cell communication under normal and diseased conditions. Exosomal miRNAs have been studied in relation to many diseases. However, there is little to no knowledge regarding the miRNA population of bronchoalveolar lavage fluid (BALF) or the lung-tissue-derived exosomes in COPD and IPF. Here, we determined and compared the miRNA profiles of BALF- and lung-tissue-derived exosomes of healthy non-smokers, smokers, and patients with COPD or IPF in independent cohorts. Results: Exosome characterization using NanoSight particle tracking and TEM demonstrated that the BALF-derived exosomes were ~89.85 nm in size with a yield of ~2.95 × 10¹⁰ particles/mL in concentration. Lung-derived exosomes were larger in size (~146.04 nm) with a higher yield of ~2.38 × 10¹¹ particles/mL. NGS results identified three differentially expressed miRNAs in the BALF, while there was one in the lung-derived exosomes from COPD patients as compared to healthy non-smokers. Of these, miR-122-5p was three- or five-fold downregulated among the lung-tissue-derived exosomes of COPD patients as compared to healthy non-smokers and smokers, respectively. Interestingly, there were a large number (55) of differentially expressed miRNAs in the lung-tissue-derived exosomes of IPF patients compared to non-smoking controls. Conclusions: Overall, we identified lung-specific miRNAs associated with chronic lung diseases that can serve as potential biomarkers or therapeutic targets.

Identifying miRNA-mRNA Networks Associated With COPD Phenotypes

Chronic obstructive pulmonary disease (COPD) is characterized by expiratory airflow limitation and symptoms such as shortness of breath. Although many studies have demonstrated dysregulated microRNA (miRNA) and gene (mRNA) expression in the pathogenesis of COPD, how miRNAs and mRNAs systematically interact and contribute to COPD development is still not clear. To gain a deeper understanding of the gene regulatory network underlying COPD pathogenesis, we used Sparse Multiple Canonical Correlation Network (SmCCNet) to integrate whole blood miRNA and RNA-sequencing data from 404 participants in the COPDGene study to identify novel miRNA-mRNA networks associated with COPD-related phenotypes including lung function and emphysema. We hypothesized that phenotype-directed interpretable miRNA-mRNA networks from SmCCNet would assist in the discovery of novel biomarkers that traditional single biomarker discovery methods (such as differential expression) might fail to discover. Additionally, we investigated whether adjusting -omics and clinical phenotypes data for covariates prior to integration would increase the statistical power for network identification. Our study demonstrated that partial covariate adjustment for age, sex, race, and CT scanner model (in the quantitative emphysema networks) improved network identification when compared with no covariate adjustment. However, further adjustment for current smoking status and relative white blood cell (WBC) proportions sometimes weakened the power for identifying lung function and emphysema networks, a phenomenon which may be due to the correlation of smoking status and WBC counts with the COPD-related phenotypes. With partial covariate adjustment, we found six miRNA-mRNA networks associated with COPD-related phenotypes. One network consists of 2 miRNAs and 28 mRNAs which had a 0.33 correlation (p = 5.40E-12) to forced expiratory volume in 1 s (FEV1) percent predicted. We also found a network of 5 miRNAs and 81 mRNAs that had a 0.45 correlation (p = 8.80E-22) to percent emphysema. The miRNA-mRNA networks associated with COPD traits provide a systems view of COPD pathogenesis and complements biomarker identification with individual miRNA or mRNA expression data.

MiR-223 is increased in lungs of patients with COPD and modulates cigarette smoke-induced pulmonary inflammation

Since microRNA (miR)-223-3p modulates inflammatory responses and COPD is associated with amplified pulmonary inflammation, we hypothesized that miR-223-3p plays a role in COPD pathogenesis. Expression of miR-223-3p was measured in lung tissue of 2 independent cohorts with COPD GOLD stage II-IV patients, never smokers and smokers without COPD. The functional role of miR-223-3p was studied in deficient mice and upon overexpression in airway epithelial cells from COPD and controls. We observed higher miR-223-3p levels in patients with COPD stage II-IV compared to (non)-smoking controls, and levels were associated with higher neutrophil numbers in bronchial biopsies of COPD patients. MiR-223-3p expression was also increased in lungs and bronchoalveolar lavage of cigarette smoke (CS)-exposed mice. CS-induced neutrophil and monocyte lung infiltration was stronger in miR-223 deficient mice upon acute (5 days) exposure, but attenuated upon sub-chronic (4 weeks) exposure. Additionally, miR-223 deficiency attenuated acute and sub-chronic CS-induced lung infiltration of dendritic cells and T lymphocytes. Finally, in vitro overexpression of miR-223-3p in non-COPD airway epithelial cells suppressed CXCL8 and GM-CSF secretion and gene expression of the pro-inflammatory transcription factor TRAF6. Importantly, this suppressive effect of miR-223-3p was compromised in COPD-derived cultures. In conclusion, we demonstrate that miR-223-3p is increased in lungs of COPD patients and CS-exposed mice, and is associated with neutrophilic inflammation. In vivo data indicate that miR-223 acts as negative regulator of acute CS-induced neutrophilic and monocytic inflammation. In vitro data suggests that miR-223-3p does so by suppressing pro-inflammatory airway epithelial responses, which is less effective in COPD epithelium.

The role of miRNAs in alveolar epithelial cells in emphysema

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease becoming one of the leading causes of mortality and morbidity globally. The significant risk factors for COPD are exposure to harmful particles such as cigarette smoke, biomass smoke, and air pollution. Pulmonary emphysema belongs to COPD and is characterized by a unique alveolar destruction pattern resulting in marked airspace enlargement. Alveolar type II (ATII) cells have stem cell potential; they proliferate and differentiate to alveolar type I cells to restore the epithelium after damage. Oxidative stress causes premature cell senescence that can contribute to emphysema development. MiRNAs regulate gene expression, are essential for maintaining ATII cell homeostasis, and their dysregulation contributes to this disease development. They also serve as biomarkers of lung diseases and potential therapeutics. In this review, we summarize recent findings on miRNAs’ role in alveolar epithelial cells in emphysema.

ACE2 Netlas: In silico Functional Characterization and Drug-Gene Interactions of ACE2 Gene Network to Understand Its Potential Involvement in COVID-19 Susceptibility

Angiotensin-converting enzyme-2 (ACE2) receptor has been identified as the key adhesion molecule for the transmission of the SARS-CoV-2. However, there is no evidence that human genetic variation in ACE2 is singularly responsible for COVID-19 susceptibility. Therefore, we performed an integrative multi-level characterization of genes that interact with ACE2 (ACE2-gene network) for their statistically enriched biological properties in the context of COVID-19. The phenome-wide association of 51 genes including ACE2 with 4,756 traits categorized into 26 phenotype categories, showed enrichment of immunological, respiratory, environmental, skeletal, dermatological, and metabolic domains (p < 4e-4). Transcriptomic regulation of ACE2-gene network was enriched for tissue-specificity in kidney, small intestine, and colon (p < 4.7e-4). Leveraging the drug-gene interaction database we identified 47 drugs, including dexamethasone and spironolactone, among others. Considering genetic variants within ± 10 kb of ACE2-network genes we identified miRNAs whose binding sites may be altered as a consequence of genetic variation. The identified miRNAs revealed statistical over-representation of inflammation, aging, diabetes, and heart conditions. The genetic variant associations in RORA, SLC12A6, and SLC6A19 genes were observed in genome-wide association study (GWAS) of COVID-19 susceptibility. We also report the GWAS-identified variant in 3p21.31 locus, serves as trans-QTL for RORA and RORC genes. Overall, functional characterization of ACE2-gene network highlights several potential mechanisms in COVID-19 susceptibility. The data can also be accessed at https://gpwhiz.github.io/ACE2Netlas/.

The Role of miRNAs in Extracellular Matrix Repair and Chronic Fibrotic Lung Diseases

The lung extracellular matrix (ECM) plays a key role in the normal architecture of the lung, from embryonic lung development to mechanical stability and elastic recoil of the breathing adult lung. The lung ECM can modulate the biophysical environment of cells through ECM stiffness, porosity, topography and insolubility. In a reciprocal interaction, lung ECM dynamics result from the synthesis, degradation and organization of ECM components by the surrounding structural and immune cells. Repeated lung injury and repair can trigger a vicious cycle of aberrant ECM protein deposition, accompanied by elevated ECM stiffness, which has a lasting effect on cell and tissue function. The processes governing the resolution of injury repair are regulated by several pathways; however, in chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary disease (IPF) these processes are compromised, resulting in impaired cell function and ECM remodeling. Current estimates show that more than 60% of the human coding transcripts are regulated by miRNAs. miRNAs are small non-coding RNAs that regulate gene expressions and modulate cellular functions. This review is focused on the current knowledge of miRNAs in regulating ECM synthesis, degradation and topography by cells and their dysregulation in asthma, COPD and IPF.

Time-resolved proteomic profiling of cigarette smoke-induced experimental chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is the third leading cause of illness and death worldwide. Current treatments aim to control symptoms with none able to reverse disease or stop its progression. We explored the major molecular changes in COPD pathogenesis.

METHODS

We employed quantitative label-based proteomics to map the changes in the lung tissue proteome of cigarette smoke-induced experimental COPD that is induced over 8 weeks and progresses over 12 weeks.

RESULTS

Quantification of 7324 proteins enabled the tracking of changes to the proteome. Alterations in protein expression profiles occurred in the induction phase, with 18 and 16 protein changes at 4- and 6-week time points, compared to age-matched controls, respectively. Strikingly, 269 proteins had altered expression after 8 weeks when the hallmark pathological features of human COPD emerge, but this dropped to 27 changes at 12 weeks with disease progression. Differentially expressed proteins were validated using other mouse and human COPD bronchial biopsy samples. Major changes in RNA biosynthesis (heterogeneous nuclear ribonucleoproteins C1/C2 [HNRNPC] and RNA-binding protein Musashi homologue 2 [MSI2]) and modulators of inflammatory responses (S100A1) were notable. Mitochondrial dysfunction and changes in oxidative stress proteins also occurred.

CONCLUSION

We provide a detailed proteomic profile, identifying proteins associated with the pathogenesis and disease progression of COPD establishing a platform to develop effective new treatment strategies.

MiR-221-3p and miR-92a-3p enhances smoking-induced inflammation in COPD

Background

Smoking is likely to facilitate airway inflammation and finally contributes to chronic obstructive pulmonary disease (COPD). This investigation was intended to elucidate miRNAs that were involved in smoking‐induced COPD.

Methods

Altogether 155 COPD patients and 77 healthy volunteers were recruited, and their serum levels of miR‐221‐3p and miR‐92a‐3p were determined. Besides, human bronchial epithelial cells (16HBECs) were purchased, and they were treated by varying concentrations of cigarette smoke extract (CSE). The 16HBECs were, additionally, transfected by miR‐221‐3p mimic, miR‐92a‐3p mimic, miR‐221‐3p inhibitor or miR‐92a‐3p inhibitor, and cytokines released by them, including TNF‐α, IL‐8, IL‐1β, and TGF‐β1, were monitored using enzyme linked immunosorbent assay (ELISA) kits.

Results

Chronic obstructive pulmonary disease patients possessed higher serum levels of miR‐221‐3p and miR‐92a‐3p than healthy volunteers (p < 0.05), and both miR‐221‐3p and miR‐92a‐3p were effective biomarkers in diagnosing stable COPD from acute exacerbation COPD. Moreover, viability of 16HBECs was undermined by CSE treatment (p < 0.05), and exposure to CSE facilitated 16HBECs’ release of TNF‐α, IL‐8, IL‐1β, and TGF‐β1 (p < 0.05). Furthermore, miR‐221‐3p/miR‐92a‐3p expression in 16HBECs was significantly suppressed after transfection of miR‐221‐3p/miR‐92a‐3p inhibitor (p < 0.05), which abated CSE‐triggered increase in cytokine production and decline in viability of 16HBECs (p < 0.05).

Conclusion

MiR‐221‐3p and miR‐92a‐3p were involved in CSE‐induced hyperinflammation of COPD, suggesting that they were favorable alternatives in diagnosing COPD patients with smoking history.

Spotlight on microRNAs in allergy and asthma

In past 10 years, microRNAs (miRNAs) have gained scientific attention due to their importance in the pathophysiology of allergic diseases and their potential as biomarkers in liquid biopsies. They act as master post‐transcriptional regulators that control most cellular processes. As one miRNA can target several mRNAs, often within the same pathway, dysregulated expression of miRNAs may alter particular cellular responses and contribute, or lead, to the development of various diseases. In this review, we give an overview of the current research on miRNAs in allergic diseases, including atopic dermatitis, allergic rhinitis, and asthma. Specifically, we discuss how individual miRNAs function in the regulation of immune responses in epithelial cells and specialized immune cells in response to different environmental factors and respiratory viruses. In addition, we review insights obtained from experiments with murine models of allergic airway and skin inflammation and offer an overview of studies focusing on miRNA discovery using profiling techniques and bioinformatic modeling of the network effect of multiple miRNAs. In conclusion, we highlight the importance of research into miRNA function in allergy and asthma to improve our knowledge of the molecular mechanisms involved in the pathogenesis of this heterogeneous group of diseases.

Transcriptome analysis reveals lung-specific miRNAs associated with impaired mucociliary clearance induced by cigarette smoke in an in vitro human airway tissue model

Exposure to cigarette smoke (CS) is strongly associated with impaired mucociliary clearance (MCC), which has been implicated in the pathogenesis of CS-induced respiratory diseases, such as chronic obstructive pulmonary diseases (COPD). In this study, we aimed to identify microRNAs (miRNAs) that are associated with impaired MCC caused by CS in an in vitro human air-liquid-interface (ALI) airway tissue model. ALI cultures were exposed to CS (diluted with 0.5 L/min, 1.0 L/min, and 4.0 L/min of clean air) from smoking five 3R4F University of Kentucky reference cigarettes under the International Organization for Standardization (ISO) machine smoking regimen, every other day for 1 week (a total of 3 days, 40 min/day). Transcriptome analyses of ALI cultures exposed to the high concentration of CS identified 5090 differentially expressed genes and 551 differentially expressed miRNAs after the third exposure. Genes involved in ciliary function and ciliogenesis were significantly perturbed by repeated CS exposures, leading to changes in cilia beating frequency and ciliary protein expression. In particular, a time-dependent decrease in the expression of miR-449a, a conserved miRNA highly enriched in ciliated airway epithelia and implicated in motile ciliogenesis, was observed in CS-exposed cultures. Similar alterations in miR-449a have been reported in smokers with COPD. Network analysis further indicates that downregulation of miR-449a by CS may derepress cell-cycle proteins, which, in turn, interferes with ciliogenesis. Investigating the effects of CS on transcriptome profile in human ALI cultures may provide not only mechanistic insights, but potential early biomarkers for CS exposure and harm.

miR-4456/CCL3/CCR5 Pathway in the Pathogenesis of Tight Junction Impairment in Chronic Obstructive Pulmonary Disease

Background: Cigarette smoke exposure (CSE) is a major cause of chronic obstructive pulmonary disease (COPD). The smoke disrupts cell-cell adhesion by inducing epithelial barrier damage to the tight junction (TJ) proteins. Even though the inflammatory mechanism of chemokine (C-C motif) ligand 3 (CCL3) in COPD has gained increasing attention in the research community, however, the underlying signaling pathway, remains unknown.

Objectives: To identify the relationship of CCL3 in the pathogenesis of tight junction impairment in COPD and the pathway through which CSE causes damage to TJ in COPD via CCL3, both in vivo and in vitro.

Methods: We screened the inflammatory factors in the peripheral blood mononuclear cells (PBMCs) from healthy controls and patients at each GOLD 1-4 stage of chronic obstructive pulmonary disease. RT-PCR, western blot, and ELISA were used to detect the levels of CCL3, ZO-1, and occludin after Cigarette smoke exposure. Immunofluorescence was applied to examine the impairment of the TJs in 16-HBE and A549 cells. The reverse assay was used to detect the effect of a CCR5 antagonist (DAPTA) in COPD. In the CSE-induced COPD mouse model, H&E staining and lung function tests were used to evaluate the pathological and physical states in each group. Immunofluorescence was used to assess the impairment of TJs in each group. ELISA and RT-PCR were used to examine the mRNA or protein expression of CCL3 or miR-4456 in each group.

Results: The in vivo and in vitro results showed that CCL3 expression was increased in COPD compared with healthy controls. CCL3 caused significant injury to TJs through its C-C chemokine receptor type 5 (CCR5), while miR-4456 could suppress the effect of CCL3 on TJs by binding to the 3′-UTR of CCL3.

Conclusion: miR-4456/CCL3/CCR5 pathway may be a potential target pathway for the treatment of COPD.

A disintegrin and metalloproteinase domain-15 deficiency leads to exaggerated cigarette smoke-induced chronic obstructive pulmonary disease (COPD)-like disease in mice

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by cells implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), but its contributions to COPD are unknown. To address this gap, ADAM15 levels were measured in samples from cigarette smoke (CS)-versus air-exposed wild-type (WT) mice. CS-induced COPD-like disease was compared in CS-exposed WT, Adam15^-/-, and Adam15 bone marrow chimeric mice. CS exposure increased Adam15 expression in lung macrophages and CD8⁺ T cells and to a lesser extent in airway epithelial cells in WT mice. CS-exposed Adam15^-/- mice had greater emphysema, small airway fibrosis, and lung inflammation (macrophages and CD8⁺ T cells) than WT mice. Adam15 bone marrow chimera studies revealed that Adam15 deficiency in leukocytes led to exaggerated pulmonary inflammation and COPD-like disease in mice. Adam15 deficiency in CD8⁺ T cells was required for the exaggerated pulmonary inflammation and COPD-like disease in CS-exposed Adam15^-/- mice (as assessed by genetically deleting CD8⁺ T cells in Adam15^-/- mice). Adam15 deficiency increased pulmonary inflammation by rendering CD8⁺ T cells and macrophages resistant to CS-induced activation of the mitochondrial apoptosis pathway by preserving mTOR signaling and intracellular Mcl-1 levels in these cells. These results strongly link ADAM15 deficiency to the pathogenesis of COPD.

MicroRNA miR-24-3p reduces DNA damage responses, apoptosis, and susceptibility to chronic obstructive pulmonary disease

The pathogenesis of chronic obstructive pulmonary disease (COPD) involves aberrant responses to cellular stress caused by chronic cigarette smoke (CS) exposure. However, not all smokers develop COPD and the critical mechanisms that regulate cellular stress responses to increase COPD susceptibility are not understood. Because microRNAs are well-known regulators of cellular stress responses, we evaluated microRNA expression arrays performed on distal parenchymal lung tissue samples from 172 subjects with and without COPD. We identified miR-24-3p as the microRNA that best correlated with radiographic emphysema and validated this finding in multiple cohorts. In a CS exposure mouse model, inhibition of miR-24-3p increased susceptibility to apoptosis, including alveolar type II epithelial cell apoptosis, and emphysema severity. In lung epithelial cells, miR-24-3p suppressed apoptosis through the BH3-only protein BIM and suppressed homology-directed DNA repair and the DNA repair protein BRCA1. Finally, we found BIM and BRCA1 were increased in COPD lung tissue, and BIM and BRCA1 expression inversely correlated with miR-24-3p. We concluded that miR-24-3p, a regulator of the cellular response to DNA damage, is decreased in COPD, and decreased miR-24-3p increases susceptibility to emphysema through increased BIM and apoptosis.

The Potential Roles of Exosomes in Chronic Obstructive Pulmonary Disease

Currently, chronic obstructive pulmonary disease (COPD) is one of the most common chronic lung diseases. Chronic obstructive pulmonary disease is characterized by progressive loss of lung function due to chronic inflammatory responses in the lungs caused by repeated exposure to harmful environmental stimuli. Chronic obstructive pulmonary disease is a persistent disease, with an estimated 384 million people worldwide living with COPD. It is listed as the third leading cause of death. Exosomes contain various components, such as lipids, microRNAs (miRNAs), long non-coding RNAs(lncRNAs), and proteins. They are essential mediators of intercellular communication and can regulate the biological properties of target cells. With the deepening of exosome research, it is found that exosomes are strictly related to the occurrence and development of COPD. Therefore, this review aims to highlight the unique role of immune-cell-derived exosomes in disease through complex interactions and their potentials as potential biomarkers new types of COPD.

MiR-218 Inhibits CSE-Induced Apoptosis and Inflammation in BEAS-2B by Targeting BRD4

Background

Chronic obstructive pulmonary disease (COPD) is an age-related disease, and its incidence rate is increasing every year. MicroRNAs (miRNAs) play critical roles in the COPD process and function as key biomarkers or potential therapeutic targets for patients with COPD. However, the potential roles and functional effects of miR-218 in COPD remain undefined.

Methods

The expression levels of miR-218 and bromodomain protein 4 (BRD4) were assessed by real-time quantitative polymerase chain reaction (RT-qPCR) or Western blot, respectively. In addition, a COPD cell model was established using cigarette smoke extract (CSE) in bronchial epithelial cell line (BEAS-2B). Enzyme-linked immunosorbent assay (ELISA) kit was applied to measure the concentrations of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8) in cell supernatants of BEAS-2B cells. Moreover, cell apoptosis was examined by flow cytometry assay. The association relationship between miR-218 and BRD4 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assay.

Results

MiR-218 was downregulated in COPD and CSE-induced BEAS-2B cells, and it was positively correlated with forced expiratory volume in 1 second (FEV1) % in COPD patients. Mechanically, overexpression of miR-218 or knockdown of BRD4 mitigated apoptosis and inflammation in BEAS-2B cells induced by CSE. Additionally, overexpression of BRD4 weakened the miR-218-mediated effects on CSE-induced BEAS-2B cells.

Conclusion

Overexpression of miR-218 inhibited CSE-induced apoptosis and inflammation in BEAS-2B cells by targeting BRD4 expression.

LINC00987 Ameliorates COPD by Regulating LPS-Induced Cell Apoptosis, Oxidative Stress, Inflammation and Autophagy Through Let-7b-5p/SIRT1 Axis

Background

Chronic obstructive pulmonary disease (COPD) is the third cause of disease-related death and brings a heavy burden to human health. Long non-coding RNA (lncRNA) was revealed to participate in COPD pathogenesis. This study aims to establish the effects and regulatory mechanism of lncRNA long intergenic non-coding 00987 (LINC00987) in lipopolysaccharide (LPS)-induced apoptosis, oxidative stress, inflammation and autophagy in BEAS-2B cells.

Methods

The expression levels of LINC00987 and let-7b-5p were detected by real-time quantitativepolymerase chain reaction (RT-qPCR). The expression of apoptosis-associated proteins, oxidative stress (ROS)-related proteins, autophagy-related proteins and sirtuin1 (SIRT1) protein was determined by Western blot. Cell viability was illustrated by cell counting kit-8 (CCK-8) assay. Cell apoptosis was investigated by caspase3 activity and apoptosis analysis assays. ROS, inflammation and autophagy were demonstrated by detecting reactive ROS level and superoxide dismutase (SOD) activity, enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, respectively. The binding sites between let-7b-5p and LINC00987 or SIRT1 were predicted by lncBase or miRWalk online database, and identified by dual-luciferase reporter assay.

Results

LINC00987 expression was strikingly downregulated and let-7b-5p expression was obviously upregulated in COPD tissues and LPS-induced BEAS-2B cells compared with control groups. LINC00987 overexpression promoted BEAS-2B cells against LPS-mediated viability, apoptosis, oxidative stress, inflammation and autophagy, whereas these effects were attenuated by let-7b-5p mimic or SIRT1 knockdown. Furthermore, LINC00987 sponged let-7b-5p and let-7b-5p bound to SIRT1.

Conclusion

LINC00987 ameliorated COPD through modulating LPS-induced cell apoptosis, oxidative stress, inflammation and autophagy via sponging let-7b-5p to associate with SIRT1. This finding will provide a theoretical basis for the research of LncRNA-mediated treatment in COPD.

ACE2 Netlas: In-silico functional characterization and drug-gene interactions of ACE2 gene network to understand its potential involvement in COVID-19 susceptibility

Angiotensin-converting enzyme-2 ( ACE2 ) receptor has been identified as the key adhesion molecule for the transmission of the SARS-CoV-2. However, there is no evidence that human genetic variation in ACE2 is singularly responsible for COVID-19 susceptibility. Therefore, we performed a multi-level characterization of genes that interact with ACE2 (ACE2-gene network) for their over-represented biological properties in the context of COVID-19. The phenome-wide association of 51 genes including ACE2 with 4,756 traits categorized into 26 phenotype categories, showed enrichment of immunological, respiratory, environmental, skeletal, dermatological, and metabolic domains (p<4e-4). Transcriptomic regulation of ACE2-gene network was enriched for tissue-specificity in kidney, small intestine, and colon (p<4.7e-4). Leveraging the drug-gene interaction database we identified 47 drugs, including dexamethasone and spironolactone, among others. Considering genetic variants within ± 10 kb of ACE2-network genes we characterized functional consequences (among others) using miRNA binding-site targets. MiRNAs affected by ACE2-network variants revealed statistical over-representation of inflammation, aging, diabetes, and heart conditions. With respect to variants mapped to the ACE2-network, we observed COVID-19 related associations in RORA, SLC12A6 and SLC6A19 genes. Overall, functional characterization of ACE2-gene network highlights several potential mechanisms in COVID-19 susceptibility. The data can also be accessed at https://gpwhiz.github.io/ACE2Netlas/.

ADAM15 expression is increased in lung CD8+ T cells, macrophages, and bronchial epithelial cells in patients with COPD and is inversely related to airflow obstruction

BACKGROUND

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by activated leukocytes, and fibroblasts in vitro. Whether ADAM15 expression is increased in the lungs of COPD patients is not known.

METHODS

ADAM15 gene expression and/or protein levels were measured in whole lung and bronchoalveolar lavage (BAL) macrophage samples obtained from COPD patients, smokers, and non-smokers. Soluble ADAM15 protein levels were measured in BAL fluid (BALF) and plasma samples from COPD patients and controls. Cells expressing ADAM15 in the lungs were identified using immunostaining. Staining for ADAM15 in different cells in the lungs was related to forced expiratory volume in 1 s (FEV1), ratio of FEV1 to forced vital capacity (FEV1/FVC), and pack-years of smoking history.

RESULTS

ADAM15 gene expression and/or protein levels were increased in alveolar macrophages and whole lung samples from COPD patients versus smokers and non-smokers. Soluble ADAM15 protein levels were similar in BALF and plasma samples from COPD patients and controls. ADAM15 immunostaining was increased in macrophages, CD8+ T cells, epithelial cells, and airway α-smooth muscle (α-SMA)-positive cells in the lungs of COPD patients. ADAM15 immunostaining in macrophages, CD8+ T cells and bronchial (but not alveolar) epithelial cells was related inversely to FEV1 and FEV1/FVC, but not to pack-years of smoking history. ADAM15 staining levels in airway α-SMA-positive cells was directly related to FEV1/FVC. Over-expressing ADAM15 in THP-1 cells reduced their release of matrix metalloproteinases and CCL2.

CONCLUSIONS

These results link increased ADAM15 expression especially in lung leukocytes and bronchial epithelial cells to the pathogenesis of COPD.

Role of lycopene in smoke-promoted chronic obstructive pulmonary disease and lung carcinogenesis

Chronic obstructive pulmonary disease (COPD) and lung cancer are a major cause of morbidity and mortality worldwide, with cigarette smoking being the single most important risk factor for both. Emerging evidence indicates alterations in reverse cholesterol transport-mediated removal of excess cholesterol from lung, and intracellular cholesterol overload to be involved in smoke-promoted COPD and lung cancer development. Since there are currently few effective treatments for COPD and lung cancer, it is important to identify food-derived, biologically active compounds, which can protect against COPD and lung cancer development. High intake of the carotenoid lycopene, as one of phytochemicals, is associated with a decreased risk of chronic lung lesions. This review article summarizes and discusses epidemiologic evidence, in vitro and in vivo studies regarding the prevention of smoke-promoted COPD and lung carcinogenesis through dietary lycopene as an effective intervention strategy. We focus on the recent research implying that lycopene preventive effect is through targeting the main genes involved in reverse cholesterol transport. This review also indicates gaps in knowledge about the function of lycopene against COPD and lung cancer, offering directions for further research.

miR-223: A Key Regulator in the Innate Immune Response in Asthma and COPD

Asthma and Chronic Obstructive Pulmonary Disease (COPD) are chronic obstructive respiratory diseases characterized by airway obstruction, inflammation, and remodeling. Recent findings indicate the importance of microRNAs (miRNAs) in the regulation of pathological processes involved in both diseases. MiRNAs have been implicated in a wide array of biological processes, such as inflammation, cell proliferation, differentiation, and death. MiR-223 is one of the miRNAs that is thought to play a role in obstructive lung disease as altered expression levels have been observed in both asthma and COPD. MiR-223 is a hematopoietic cell–derived miRNA that plays a role in regulation of monocyte-macrophage differentiation, neutrophil recruitment, and pro-inflammatory responses and that can be transferred to non-myeloid cells via extracellular vesicles or lipoproteins. In this translational review, we highlight the role of miR-223 in obstructive respiratory diseases, focusing on expression data in clinical samples of asthma and COPD, in vivo experiments in mouse models and in vitro functional studies. Furthermore, we provide an overview of the mechanisms by which miR-223 regulates gene expression. We specifically focus on immune cell development and activation and involvement in immune responses, which are important in asthma and COPD. Collectively, this review demonstrates the importance of miR-223 in obstructive respiratory diseases and explores its therapeutic potential in the pathogenesis of asthma and COPD.

Participation of the miR-22-HDAC4-DLCO Axis in Patients with COPD by Tobacco and Biomass

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation and systemic inflammation. The main causes of COPD include interaction between genetic and environmental factors associated with tobacco smoking (COPD-TS) and/or exposure to biomass smoke (COPD-BS). Several microRNAs (miRNAs) control posttranscriptional regulation of COPD-TS associated gene expression. The miR-22-HDAC4-IL-17 axis was recently characterized. It is still unknown, however, whether this axis, participates in COPD-BS. To investigate, 50 patients diagnosed with severe-to-very severe COPD GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages III/IV, were recruited, 25 women had COPD-BS (never smokers, exposed heavily to BS) and 25 had COPD-TS. Serum levels of miRNA-22-3p were measured by RT (Reverse Transcription)-qPCR, while the concentration of HDAC4 (Histone deacetylase 4) was detected by ELISA. Additionally, we looked for association between serum HDAC4 and DLCOsb (Single-breath diffusing capacity of the lung for carbon monoxide), as % of predicted by age, height, and gender, one of the main differences described between COPD-BS and COPD-TS. Women with COPD-BS were older and shorter and had a higher DLCOsb %P (percent predicted) compared to COPD-TS. Serum miR-22-3p was downregulated in COPD-BS relative to COPD-TS. In contrast, the concentration of HDAC4 was higher in COPD-BS compared to COPD-TS. Furthermore, a positive correlation between serum HDAC4 levels and DLCOsb %P was observed. We concluded that the miR-22-HDAC4-DLCO axis behaves differently in patients with COPD-BS and COPD-TS.

Marked TGF-β-regulated miRNA expression changes in both COPD and control lung fibroblasts

COPD is associated with disturbed tissue repair, possibly due to TGF-β-regulated miRNA changes in fibroblasts. Our aim was to identify TGF-β-regulated miRNAs and their differential regulation and expression in COPD compared to control fibroblasts. Small RNA sequencing was performed on TGF-β-stimulated and unstimulated lung fibroblasts from 15 COPD patients and 15 controls. Linear regression was used to identify TGF-β-regulated and COPD-associated miRNAs. Interaction analysis was performed to compare miRNAs that responded differently to TGF-β in COPD and control. Re-analysis of previously generated Ago2-IP data and Enrichr were used to identify presence and function of potential target genes in the miRNA-targetome of lung fibroblasts. In total, 46 TGF-β-regulated miRNAs were identified in COPD and 86 in control fibroblasts (FDR < 0.05). MiR-27a-5p was the most significantly upregulated miRNA. MiR-148b-3p, miR-589-5p and miR-376b-3p responded differently to TGF-β in COPD compared to control (FDR < 0.25). MiR-660-5p was significantly upregulated in COPD compared to control (FDR < 0.05). Several predicted targets of miR-27a-5p, miR-148b-3p and miR-660-5p were present in the miRNA-targetome, and were mainly involved in the regulation of gene transcription. In conclusion, altered TGF-β-induced miRNA regulation and differential expression of miR-660-5p in COPD fibroblasts, may represent one of the mechanisms underlying aberrant tissue repair and remodelling in COPD.

The role of epigenetics in the development of childhood asthma

Introduction: The development of childhood asthma is caused by a combination of genetic factors and environmental exposures. Epigenetics describes mechanisms of (heritable) regulation of gene expression that occur without changes in DNA sequence. Epigenetics is strongly related to aging, is cell-type specific, and includes DNA methylation, noncoding RNAs, and histone modifications.Areas covered: This review summarizes recent epigenetic studies of childhood asthma in humans, which mostly involve studies of DNA methylation published in the recent five years. Environmental exposures, in particular cigarette smoking, have significant impact on epigenetic changes, but few of these epigenetic signals are also associated with asthma. Several asthma-associated genetic variants relate to DNA methylation. Epigenetic signals can be better understood by studying their correlation with gene expression, which revealed higher presence and activation of blood eosinophils in asthma. Strong associations of nasal methylation signatures and atopic asthma were identified, which were replicable across different populations.Expert commentary: Epigenetic markers have been strongly associated with asthma, and might serve as biomarker of asthma. The causal and longitudinal relationships between epigenetics and disease, and between environmental exposures and epigenetic changes need to be further investigated. Efforts should be made to understand cell-type-specific epigenetic mechanisms in asthma.

Small RNA-sequence analysis of plasma-derived extracellular vesicle miRNAs in smokers and patients with chronic obstructive pulmonary disease as circulating biomarkers

Extracellular vesicles (EVs) play a vital role in normal lung physiology to maintain homeostasis in the airways via intercellular communication. EVs include exosomes and microvesicles, and are characterized by their phospholipid bilayers. EVs have been recognized as novel circulating biomarkers of disease, which are released by different cell types. In this study, we used different EV isolation and purification methods to characterize the plasma-derived EV miRNAs from non-smokers, smokers and patients with COPD. A small RNA sequencing (RNA-seq) approach was adapted to identify novel circulating EV miRNAs. We found that plasma-derived EVs from non-smokers, smokers and patients with COPD vary in their size, concentration, distribution and phenotypic characteristics as confirmed by nanoparticle tracking analysis, transmission electron microscopy, and immunoblot analysis of EV surface markers. RNA-seq analysis confirmed the most abundant types of small RNAs, such as miRNAs, tRNAs, piRNAs snRNAs, snoRNAs and other biotypes in plasma-derived EVs. We mainly focused on miRNAs as novel biomarkers in smokers and patients with COPD for further analysis. Differential expression by DESeq2 identified distinct miRNA profiles (up-regulated: miR-22-3p, miR-99a-5p, miR-151a-5p, miR-320b, miR-320d; and down-regulated: miR-335-5p, miR-628-3p, miR-887-5p and miR-937-3p) in COPD versus smokers or non-smokers in a pairwise comparison. Gene set enrichment analysis (GSEA) of differentially expressed miRNAs revealed the top pathways, gene ontology and diseases associated with smokers and patients with COPD. We selectively validated miRNAs in EVs isolated from BEAS-2B cells treated with cigarette smoke extract by quantitative PCR analysis. For the first time, we report that plasma-derived EV miRNAs are novel circulating pulmonary disease biomarkers. Thus, molecular profiling of EV miRNAs has great translational potential for the development of biomarkers that may be used in the diagnosis, prognosis, and therapeutics of COPD.

Hyperoxia causes miR199a-5p-mediated injury in the developing lung

BACKGROUND

Hyperoxia-induced acute lung injury (HALI) is characterized by increased permeability and infiltration of inflammatory cells, impairment of alveolar development, and compromised lung function. Recent evidence has determined that microRNAs (miRs) are implicated in hyperoxia-induced lung injury, including bronchopulmonary dysplasia (BPD). However, the expression profile and functional role of miR199a-5p in developing lungs have not been reported.

METHODS

The present study was undertaken to explore the role of miR199a-5p in developing mice lungs and human neonates. We exposed neonatal mice for 7 days, mouse lung epithelial cells (MLE12), mouse lung endothelial cells (MLECs), and macrophages (RAW246.7), to hyperoxia at different time points.

RESULTS

Our results demonstrated enhanced miR199a-5p expression in hyperoxia-exposed mice lungs and cells, as well as in tracheal aspirates of infants developing BPD, with significant reduction in the expression of its target, caveolin-1. Next, we observed that miR199a-5p-mimic worsens HALI as evidenced by increased inflammatory cells, cytokines, and lung vascular markers. Conversely, miR199a-5p-inhibitor treatment attenuated HALI.

CONCLUSION

Thus, our findings suggest that miR199a-5p is a potential target for attenuating HALI pathophysiology in the developing lung. Moreover, miR199a-5p-inhibitor could be part of a novel therapeutic strategy for improving BPD in preterm neonates.

MicroRNA-206 promotes lipopolysaccharide-induced inflammation injury via regulation of IRAK1 in MRC-5 cells

BACKGROUND

MicroRNAs (miRNAs) have been reported to play crucial role in the airway inflammatory diseases. However, the involvement of miR-206 in airway inflammatory diseases is still uninvestigated. The study aimed to explore the effect of miR-206 on lipopolysaccharide (LPS)-induced inflammation injury in MRC-5 cells, and point out a potential relevance for chronic obstructive pulmonary disease (COPD).

METHODS

LPS was utilized to expose MRC-5 cells, then cell viability, cell migration, apoptosis, apoptosis-associated factors, as well as the concentrations and protein levels of IL-6 and IL-8 were explored. After transfected with miR-206 mimic and inhibitor, above parameters were reassessed in LPS-injured cells. Expression level of IRAK1 was examined in miR-206 mimic/inhibitor transfected cells by using RT-qPCR. The effect of IRAK1 on LPS-induced inflammation injury was investigated in MRC-5 cells after transfection with pc-IRAK1 and sh-IRAK1. The effects of miR-206 and IRAK1 on MEK/ERK and JNK pathways were determined by western blot assay.

RESULTS

LPS significantly triggered inflammation injury in MRC-5 cells by inhibiting cell viability, suppressing the healing of scratches, inducing cell apoptosis, down-regulating Bcl-2 expression and up-regulating Bax, cleaved-Caspase-3 and cleaved-Caspase-9 expression, and concurrently increasing the concentrations and the protein levels of IL-6 and IL-8. MiR-206 overexpression aggravated LPS-induced inflammation injury in MRC-5 cells. Up-regulation of IRAK1 was observed in miR-206 mimic-transfected cells. Moreover, IRAK1 overexpression promoted LPS-induced inflammation injury in MRC-5 cells. MiR-206 activated MEK/ERK and JNK pathways by regulating IRAK1.

CONCLUSIONS

MiR-206 promotes LPS-induced inflammation injury through regulation of IRAK1 in MRC-5 cells.

Role of miRNA-181a-2-3p in cadmium-induced inflammatory responses of human bronchial epithelial cells

Background

Inflammation is an important priming event in the pathogenesis of pulmonary diseases, including chronic obstructive pulmonary disease (COPD). Increasing evidence indicates that microRNAs (miRNAs) contribute to the pathogenesis of COPD by regulating inflammatory response. Therefore, it is necessary to investigate novel molecular targets in COPD without any validation in COPD samples in airway inflammation. The aim of our study is to reveal novel miRNAs that can influence molecular targets for COPD and to examine the underlying mechanism in airway inflammation.

Methods

We identified the downregulation of miR-181a-2-3p in the serum of COPD patients and further investigated the role of miR-181a-2-3p in cadmium (Cd)-induced inflammation of a human bronchial epithelial cell line (BEAS-2B) and normal human bronchial epithelial (NHBE) cells.

Results

Our results showed that expression of miR-181a-2-3p was significantly decreased in Cd-treated cells and silencing of miR-181a-2-3p enhanced Cd-induced inflammatory responses and inflammasome activation. This negative regulatory effect of miR-181a-2-3p on inflammation is partly mediated by the calcium signaling pathway. Furthermore, global gene expression profiling revealed that Toll-like receptor 4 or sequestosome 1 genes were identified as potential targets of miR-181a-2-3p, which were significantly upregulated by knockdown of miR-181a-2-3p in Cd-treated cells.

Conclusions

Our results strongly suggest that miR-181a-2-3p has a critical role in Cd-induced inflammation of airway by regulating its potential target genes, which could be molecular targets for COPD.

Lycopene Inhibits Smoke-Induced Chronic Obstructive Pulmonary Disease and Lung Carcinogenesis by Modulating Reverse Cholesterol Transport in Ferrets

Chronic obstructive pulmonary disease (COPD) and lung cancer share the same etiologic factor, cigarette smoking. Higher consumption of dietary lycopene has been associated with lower risks of COPD and lung cancer in smokers. We investigated whether lycopene feeding protects against COPD and lung cancer in ferrets, a nonrodent model that closely mimics cigarette smoke (CS)-induced chronic bronchitis, emphysema, and lung tumorigenesis in human. We also explored whether the protective effect of lycopene is associated with restoring reverse cholesterol transport (RCT), a key driver in persistent inflammation with CS exposure. Ferrets (4 groups, n = 12-16/group) were exposed to a combination of tobacco carcinogen (NNK) and CS with or without consuming lycopene at low and high doses (equivalent to ∼30 and ∼90 mg lycopene/day in human, respectively) for 22 weeks. Results showed that dietary lycopene at a high dose significantly inhibited NNK/CS-induced chronic bronchitis, emphysema, and preneoplastic lesions, including squamous metaplasia and atypical adenomatous hyperplasia, as compared with the NNK/CS alone (P < 0.05). Lycopene feeding also tended to decrease the lung neoplastic lesions. Furthermore, lycopene feeding significantly inhibited NNK/CS-induced accumulation of total cholesterol, and increased mRNA expression of critical genes related to the RCT (PPARα, LXRα, and ATP-binding cassette transporters ABCA1 and ABCG1) in the lungs, which were downregulated by the NNK/CS exposure. The present study has provided the first evidence linking a protective role of dietary lycopene against COPD and preneoplastic lesions to RCT-mediated cholesterol accumulation in lungs.

Cigarette smoke extract alters genome-wide profiles of circular RNAs and mRNAs in primary human small airway epithelial cells

As a novel kind of non-coding RNA, circular RNAs (circRNAs) were involved in various biological processes. However, the role of circRNAs in the developmental process of chronic obstructive pulmonary disease (COPD) is still unclear. In the present study, by using a cell model of COPD in primary human small airway epithelial cells (HSAECs) treated with or without cigarette smoke extract (CSE), we uncovered 4,379 previously unknown circRNAs in human cells and 903 smoke-specific circRNAs, with the help of RNA-sequencing and bioinformatic analysis. Moreover, 3,872 up- and 4,425 down-regulated mRNAs were also identified under CSE stimulation. Furthermore, a putative circRNA-microRNA-mRNA network was constructed for in-depth mechanism exploration, which indicated that differentially expressed circRNAs could influence expression of some key genes that participate in response to pentose phosphate pathway, ATP-binding cassette (ABC) transporters, glycosaminoglycan biosynthesis pathway and cancer-related pathways. Our research indicated that cigarette smoke had an influence on the biogenesis of circRNAs and mRNAs. CircRNAs might be involved in the response to CSE in COPD through the circRNA-mediated ceRNA networks.

Decreased miR-29b expression is associated with airway inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common chronic airway inflammatory disease. MicroRNAs are shown to be involved in the regulation of inflammation. We investigated the role of microRNA-29b (miR-29b) in the airway inflammation in COPD. The expression of miR-29b in the lung and plasma was examined. The target of miR-29b, bromodomain protein 4 (BRD4), was predicted by online algorithms and verified in human bronchial epithelial (HBE) cells. The expression of BRD4, interleukin (IL)-8, and IL-6 in the lung was also examined. The role of miR-29b in the inflammatory cytokine expression of airway epithelial cells was studied using an in vitro model system. In total, 60 subjects were recruited, including 10 nonsmokers, 24 smokers, and 26 patients with COPD. Both lung and plasma miR-29b are decreased in patients with COPD, and miR-29b expression levels are correlated with pulmonary function and inflammation. BRD4 is increased in the lung of patients with COPD and is correlated with miR-29b and IL-8 expression. miR-29b regulates cigarette smoke extract (CSE)-induced IL-8 expression by targeting BRD4 in HBE cells. The antioxidant N-acetylcysteine prevents CSE-induced miR-29b downregulation and BRD4 and IL-8 upregulation. Our findings indicate that miR-29b may participate in the airway inflammation in COPD by regulating inflammatory cytokine expression through targeting BRD4, plasma miR-29b may serve as a biomarker for disease severity in COPD, and oxidative stress may contribute to the decrease of miR-29b induced by cigarette smoke.

The roles of microRNAs in the pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by a progressive and irreversible airflow obstruction, with an abnormal lung function. The etiology of COPD correlates with complex interactions between environmental and genetic determinants. However, the exact pathogenesis of COPD is obscure although it involves multiple aspects including oxidative stress, imbalance between proteolytic and anti-proteolytic activity, immunity and inflammation, apoptosis, and repair and destruction in both airways and lungs. Many genes have been demonstrated to be involved in those pathogenic processes of this disease in patients exposed to harmful environmental factors. Previous reports have investigated promising microRNAs (miRNAs) to disclose the molecular mechanisms for COPD development induced by different environmental exposure and genetic predisposition encounter, and find some potential miRNA biomarkers for early diagnosis and treatment targets of COPD. In this review, we summarized the expression profiles of the reported miRNAs from studies of COPD associated with environmental risk factors including cigarette smoking and air pollution exposures, and provided an overview of roles of those miRNAs in the pathogenesis of the disease. We also highlighted the potential utility and limitations of miRNAs serving as diagnostic biomarkers and therapeutic targets for COPD.

microRNA-mRNA regulatory networks underlying chronic mucus hypersecretion in COPD

Chronic mucus hypersecretion (CMH) is a common feature in chronic obstructive pulmonary disease (COPD) and is associated with worse prognosis and quality of life. This study aimed to identify microRNA (miRNA)-mRNA regulatory networks underlying CMH.The expression profiles of miRNA and mRNA in bronchial biopsies from 63 COPD patients were associated with CMH using linear regression. Potential mRNA targets of each CMH-associated miRNA were identified using Pearson correlations. Gene set enrichment analysis (GSEA) and STRING (search tool for the retrieval of interacting genes/proteins) analysis were used to identify key genes and pathways.20 miRNAs and 539 mRNAs were differentially expressed with CMH in COPD. The expression of 10 miRNAs was significantly correlated with the expression of one or more mRNAs. Of these, miR-134-5p, miR-146a-5p and the let-7 family had the highest representation of CMH-associated mRNAs among their negatively correlated predicted targets. KRAS and EDN1 were identified as key regulators of CMH and were negatively correlated predicted targets of miR-134-5p and let-7a-5p, let-7d-5p, and let-7f-5p, respectively. GSEA suggested involvement of MUC5AC-related genes and several other relevant gene sets in CMH. The lower expression of miR-134-5p was confirmed in primary airway fibroblasts from COPD patients with CMH.We identified miR-134-5p, miR-146a-5p and let-7 family, along with their potential target genes including KRAS and EDN1, as potential key miRNA-mRNA networks regulating CMH in COPD.

Possible mechanisms mediating apoptosis of bronchial epithelial cells in chronic obstructive pulmonary disease - A next-generation sequencing approach

PURPOSE

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by persistent airflow limitation. Apoptosis of pulmonary structural cells contributes to pulmonary destruction and dysfunction. This study aimed to explore the possible mechanisms underlying decreased cell proliferation and increased apoptosis of bronchial epithelial cells of COPD.

MATERIALS AND METHODS

The expression profiles of mRNAs and microRNAs in bronchial epithelial cells from a COPD patient and a normal subject were identified using next-generation sequencing (NGS) and analyzed using bioinformatic tools.

RESULTS

We identified 233 significantly upregulated and 204 significantly downregulated genes in COPD bronchial epithelial cells. The PI3K-Akt pathway was one of the most important dysregulated pathways in bronchial epithelial cells. We further identified that 3 genes involved in the PI3K-Akt signaling pathway, including IL6, F2R, and FGFR3, might be associated with inhibition of cell proliferation in bronchial epithelial cells, while 5 genes involved in the PI3K-Akt signaling pathway, including TLR4, IL6, F2R, FGFR3, and FGFR1, might be associated with apoptosis of bronchial epithelial cells. FGFR1 was also a predicted target for some up-regulated miRNAs in COPD bronchial epithelial cells, including hsa-miR-195-5p, hsa-miR-424-5p, and hsa-miR-6724-5p.

CONCLUSION

Our findings suggest PI3K-Akt signaling pathway plays an important role in COPD. We observed altered expression of apoptosis and cell proliferation-related genes that might contribute to the pathogenesis of COPD.

PM2.5 downregulates miR-194-3p and accelerates apoptosis in cigarette-inflamed bronchial epithelium by targeting death-associated protein kinase 1

Background

Persistent exposure to cigarette smoke or biomass fuels induces oxidative stress and apoptosis in bronchial epithelium, which is one of the most important pathogenic mechanisms of chronic obstructive pulmonary disease (COPD). Fine particulate matter (PM_2.5) is an aggravating risk factor of COPD exacerbation. Animal evidence showed PM_2.5accelerated lung inflammation and oxidative stress in COPD mice, but the mechanism is still not clear. Recently, we found that miR-194-3p is a novel biomarker of both COPD and PM_2.5 exposure, and miR-194 family has been reported to be involved in cell proliferation and apoptosis. Thus, we propose a hypothesis: PM_2.5 can accelerate apoptotic response of airway epithelial cells in COPD and miR-194 is a potential involved regulator.

Materials and methods

Human bronchial epithelial cells (HBEpiCs) were treated with normal media, cigarette smoke solution (CSS) and PM_2.5-CSS for 24 h. miR-194-3p mimics, inhibitors and scrambled controls were non-transfected or pre-transfected into HBEpiCs for 48 h. MircroRNAs and mRNA expression were quantified by qRT-PCR. Protein expression was analyzed by western blotting. Caspase activities, mitochondrial membrane potential and TUNEL-positive cells were detected to analyze apoptosis. Bioinformatics and luciferase analysis were used to identify the predicted binding site of miR-194-3p and potential targets.

Results

In our study, we found that PM_2.5 significantly aggravated apoptosis in cigarette-inflamed HBEpiCs. miR-194-3p was dramatically downregulated in PM_2.5-CSS-treated HBEpiCs. Bioinformatics and luciferase experiments reported that death-associated protein kinase 1 (DAPK1), regulating caspase 3 activities in apoptosis, was directly targeted by miR-194-3p. Inhibition of miR-194-3p increased DAPK1 expression and apoptosis in normal HBEpiCs. Importantly, overexpression of miR-194-3p suppressed apoptosis in PM_2.5-CSS HBEpiCs.

Conclusion

These results suggested that miR-194-3p was a protective regulator involved in apoptosis pathway and a potential therapeutic target for treatment of bronchial epithelial injury aggravation induced by PM_2.5.

A Disintegrin and A Metalloproteinase-9 (ADAM9): A Novel Proteinase Culprit with Multifarious Contributions to COPD

INTRODUCTION

Proteinases with a disintegrin and a metalloproteinase domain (ADAMs) have not been well studied in COPD. We investigated whether ADAM9 is linked to COPD in humans and mice.

METHODS

ADAM9 blood and lung levels were measured in COPD patients versus controls, and air- versus cigarette smoke (CS)-exposed wild-type (WT) mice. WT and Adam9-/- mice were exposed to air or CS for 1-6 months, and COPD-like lung pathologies were measured.

RESULTS

ADAM9 staining was increased in lung epithelial cells and macrophages in smokers and even more so in COPD patients and correlated directly with pack-year smoking history and inversely with airflow obstruction and/or FEV1 % predicted. Bronchial epithelial cell ADAM9 mRNA levels were higher in COPD patients than controls and correlated directly with pack-year smoking history. Plasma, BALF and sputum ADAM9 levels were similar in COPD patients and controls. CS exposure increased Adam9 levels in WT murine lungs. Adam9-/- mice were protected from emphysema development, small airway fibrosis, and airway mucus metaplasia. CS-exposed Adam9-/- mice had reduced lung macrophage counts, alveolar septal cell apoptosis, lung elastin degradation, and shedding of VEGFR2 and EGFR in BALF samples. Recombinant ADAM9 sheds EGF and VEGF receptors from epithelial cells to reduce activation of the Akt pro-survival pathway and increase cellular apoptosis.

CONCLUSIONS

ADAM9 levels are increased in COPD lungs and linked to key clinical variables. Adam9 promotes emphysema development, and large and small airway disease in mice. Inhibition of ADAM9 could be a therapeutic approach for multiple COPD phenotypes.

The role of noncoding RNAs in regulating epithelial responses in COPD

Chronic obstructive pulmonary disease (COPD), one of the leading causes of death in the world, is a chronic inflammatory disease of the airways usually caused by long-term exposure to inhaled irritants. Airway epithelial cells (AECs) play a key role in initializing COPD and driving the exacerbation of this disease through the release of various cytokines. This AEC-derived cytokine response is tightly regulated possibly through the regulatory effects of noncoding RNAs (ncRNAs). Although the importance of ncRNAs in pulmonary diseases has been increasingly realized, little is known about the role of ncRNA in the regulation of inflammatory responses in COPD. This review outlines the features of AEC-derived cytokine responses in COPD and how ncRNAs regulate these inflammatory responses.