CircRNA0001859, a new diagnostic and prognostic biomarkers for COPD and AECOPD

ADAR1-HNRNPL-Mediated CircCANX Decline Promotes Autophagy in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a characteristic chronic airway inflammatory disease that worsens over time, however, there are currently limited clinical therapeutics to suspend its progression. Circular RNAs (circRNAs), which have emerged as functional regulators in various diseases, including COPD, may server as new pharmacological targets in COPD. Here, it is identified a nuclear circRNA, circCANX, that is preferentially decreased in COPD. The linear splicing of CANX pre-mRNA, enhanced by the ADAR1-HNRNPL interaction, is responsible for the circCANX decline. Clinically, the higher circCANX expression is associated with a worse lung function index of FEV1/FVC among patients with COPD. CircCANX suppresses autophagy and stress granule (SG) formation to strengthen inflammation of COPD in vivo and in vitro. Mechanistically, circCANX recruits the tumor suppressor protein P53 (P53) mRNA and RNA helicase upstream frameshift 1 (UPF1) to form a ternary complex, which mediates P53 mRNA degradation through nonsense-mediated mRNA decay (NMD) process. Together, this study reveals an important circCANX-mediated regulatory mechanism in COPD, and provides new insights into the potential of circRNA-based drug and biomarker development for COPD.

Role of circRMRP and circRPL27 in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death and disability worldwide, and circRNA dysregulation is functionally associated with COPD. This study explored the potential of circRMRP and circRPL27 as biomarkers of COPD. Blood samples from COPD patients and healthy controls were collected. COPD patients were divided into mild, moderate, and severe groups according to lung function. Quantitative real-time polymerase chain reaction technology was used to determine the expression of circRPL27 and circRMRP in COPD. Receiver operating characteristic curve was drawn to explore the value of circRMRP and circRPL27 in diagnosing COPD. circRMRP and circRPL27 levels were elevated in serum of COPD patients and increased with the severity of COPD. CircRMRP and circRPL27 were associated with smoking history, WBC, and FEV1/FVC, and were positively correlated with smoking history and WBC, and negatively correlated with FEV1/FVC. In COPD, both circRMRP and circRPL27 had diagnostic values, but circRPL27 was better. circRMRP and circRPL27 may be useful non-invasive biomarkers for COPD diagnosis.

Circular RNA circNIPBL regulates TP53-H179R mutations in NNK-induced bronchial epithelial carcinogenesis

Exposure to environmental carcinogens is a significant contributor to cancer development, with genetic and epigenetic alterations playing pivotal roles in the carcinogenic process. However, the interplay between epigenetic regulation and genetic changes in carcinogenesis has yet to receive comprehensive attention. This study investigates the impact of continuous exposure to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) on bronchial epithelial cells, leading to malignant transformation. Our findings reveal the down-regulation of the tumor suppressor-like circular RNA circNIPBL during oncogenic processes concomitant with the accumulation of the TP53-H179R, a single nucleotide variant. Diminished circNIPBL expression enhances the proliferative, distant metastatic, and tumor-forming capabilities of NNK-induced cancerous cells and lung cancer cell lines (A549, H1299), while also promoting the accumulation of TP53-H179R during NNK-induced carcinogenesis. Mechanistic investigations demonstrate that circNIPBL interacts with HSP90α to regulate the translocation of AHR into the nucleus, which may be a potential regulatory mechanism for NNK-induced carcinogenesis and TP53-H179R accumulation. This study introduces a novel perspective on the interplay between genetic alterations and epigenetic regulation in chemical carcinogenesis, which provides novel insight into the etiology of cancer.

circADAMTS6 via stabilizing CAMK2A is involved in smoking-induced emphysema through driving M2 macrophage polarization

Cigarette smoke (CS), an indoor environmental pollutant, is a prominent risk factor for emphysema, which is a pathological feature of chronic obstructive pulmonary disease (COPD). Emerging function of circRNAs in immune responses and disease progression shed new light to explore the pathogenesis of emphysema. In this research, we demonstrated, by single-cell RNA sequencing (scRNAseq), that the ratio of M2 macrophages were increased in lung tissues of humans and mice with smoking-related emphysema. Further, our data showed that circADAMTS6 was associated with cigarette smoke extract (CSE)-induced M2 macrophage polarization. Mechanistically, in macrophages, circADAMTS6 stabilized CAMK2A mRNA via forming a circADAMTS6/IGF2BP2/CAMK2A RNA-protein ternary complex to activate CREB, which drives M2 macrophage polarization and leads to emphysema. In addition, in macrophages of mouse lung tissues, downregulation of circADAMTS6 reversed M2 macrophage polarization, the proteinase/anti-proteinase imbalance, and the elastin degradation, which protecting against CS-induced emphysema. Moreover, for macrophages and in a model with co-cultured lung organoids, the target of circADAMTS6 restored the growth of lung organoids compared to CSE-treated macrophages. Our results also demonstrated that, for smokers and COPD smokers, elevation of circADAMTS6 negatively correlated with lung function. Overall, this study reveals a novel mechanism for circADAMTS6-driven M2 macrophage polarization in smoking-related emphysema and postulates that circADAMTS6 could serve as a diagnostic and therapeutic marker for smoking-related emphysema.

Long non-coding RNA Small Nucleolar RNA Host Gene 4 ameliorates cigarette smoke-induced proliferation, apoptosis, inflammation, and airway remodeling in alveolar epithelial cells through the modulation of the mitogen-activated protein kinase signaling pathway via the microRNA-409-3p/Four and a Half LIM Domains 1 axis

The long non-coding RNA (lncRNA) Small Nucleolar RNA Host Gene 4 (SNHG4) has been demonstrated to be significantly downregulated in various inflammatory conditions, yet its role in chronic obstructive pulmonary disease (COPD) remains elusive. This study aims to elucidate the biological function of SNHG4 in COPD and to unveil its potential molecular targets. Our findings reveal that both SNHG4 and Four and a Half LIM Domains 1 (FHL1) were markedly downregulated in COPD, whereas microRNA-409-3p (miR-409-3p) was upregulated. Importantly, SNHG4 exhibited a negative correlation with inflammatory markers in patients with COPD, but a positive correlation with forced expiratory volume in 1s percentage (FEV1%). SNHG4 distinguished COPD patients from non-smokers with high sensitivity, specificity, and accuracy. Overexpression of SNHG4 ameliorated cigarette smoke extract (CSE)-mediated inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE bronchial epithelial cells. These beneficial effects of SNHG4 overexpression were reversed by the overexpression of miR-409-3p or the silencing of FHL1. Mechanistically, SNHG4 competitively bound to miR-409-3p, mediating the expression of FHL1, and consequently improving inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE cells. Additionally, SNHG4 regulated the miR-409-3p/FHL1 axis to inhibit the activation of the mitogen-activated protein kinase (MAPK) pathway induced by CSE. In a murine model of COPD, knockdown of SNHG4 exacerbated CSE-induced pulmonary inflammation, apoptosis, and oxidative stress. In summary, our data affirm that SNHG4 mitigates pulmonary inflammation, apoptosis, and oxidative damage mediated by COPD through the regulation of the miR-409-3p/FHL1 axis.

Unwinding circular RNA's role in inflammatory pulmonary diseases

Circular RNAs (circRNAs) have emerged as pivotal regulators of gene expression and cellular processes in various physiological and pathological conditions. In recent years, there has been a growing interest in investigating the role of circRNAs in inflammatory lung diseases, owing to their potential to modulate inflammation-associated pathways and contribute to disease pathogenesis. Inflammatory lung diseases, like asthma, chronic obstructive pulmonary disease (COPD), and COVID-19, pose significant global health challenges. The dysregulation of inflammatory responses demonstrates a pivotal function in advancing these diseases. CircRNAs have been identified as important players in regulating inflammation by functioning as miRNA sponges, engaging with RNA-binding proteins, and participating in intricate ceRNA networks. These interactions enable circRNAs to regulate the manifestation of key inflammatory genes and signaling pathways. Furthermore, emerging evidence suggests that specific circRNAs are differentially expressed in response to inflammatory stimuli and exhibit distinct patterns in various lung diseases. Their involvement in immune cell activation, cytokine production, and tissue remodeling processes underscores their possible capabilities as therapeutic targets and diagnostic biomarkers. Harnessing the knowledge of circRNA-mediated regulation in inflammatory lung diseases could lead to the development of innovative strategies for disease management and intervention. This review summarizes the current understanding of the role of circRNAs in inflammatory lung diseases, focusing on their regulatory mechanisms and functional implications.

Circular RNA_0025843 Alleviated Cigarette Smoke Extract Induced Bronchoalveolar Epithelial Cells Ferroptosis

Purpose

Circular RNA (circRNA) plays an important role in various biological processes. However, their functions in cigarette smoke extract (CSE) induced human normal lung epithelial cells (BEAS-2B) injury remain vague. The study aimed to explore circRNA expression profiles and reveal their potential roles in CSE-treated BEAS-2B cells.

Methods

5% CSE exposure for 24 hours were used to build the BEAS-2B cells ferroptosis model. Differentially expressed circRNAs (DECs) were identified by next-generation RNA sequencing. Six randomly selected DECs were validated via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) analysis were conducted to clarify the potential functions of the DECs. Furthermore, the role of hsa_circ_0025843 in CSE-related BEAS-2B cells ferroptosis was confirmed.

Results

5% CSE exposure induced BEAS-2B cells ferroptosis. Fifty-one up-regulated cirRNAs and 80 down-regulated circRNAs were revealed in CSE-treated BEAS-2B cells. Hsa_circ_0003461, hsa_circ_0007548, hsa_circ_0025843, hsa_circ_0068896, hsa_circ_0005832, and hsa_circ_0053378 were selected randomly to validate the reliability of next-generation RNA sequencing by qRT-PCR. After KEGG pathway analysis, DECs were found to participate in the process of EGFR tyrosine kinase inhibitor resistance and glycerophospholipid metabolism. The knockdown of hsa_circ_0025843 significantly alleviated CSE-induced BEAS-2B cells ferroptosis.

Conclusion

The study indicated the circRNA expression profiles in CSE-treated BEAS-2B cells. Hsa_circ_0025843 alleviated CSE induced BEAS-2B cells ferroptosis, which might be a potential therapeutic target of CSE related lung injury.

Hsa_circ_0008833 promotes COPD progression via inducing pyroptosis in bronchial epithelial cells

Purpose: Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder. Pyroptosis represents a distinctive form of inflammatory cell death that is mediated through the activation of Caspase-1 and inflammasomes. CircRNAs have emerged as a novel class of biomolecules with implications in various human diseases. This study aims to investigate the circRNAs profile of in COPD progression and identify pivotal circRNAs associated with the development of this disease. Methods: he expression profiles of circRNAs in peripheral blood mononuclear cells of COPD patients were assessed by circRNA microarray. Furthermore, flag-labeled vectors were constructed to assess the potential protein-coding capacity of has-circ-0008833. 16HBE cells were stably transfected with lentivirus approach, and cell proliferation and death were assessed to clarify the functional roles of has-circ-0008833 and its encoded protein circ-0008833aa. Additionally, western blot analysis was furthered performed to determine the level of Caspase-1, IL-18, IL-1β, NLRP3, ASC, and cleaved GSDMD regulated by has-circ-0008833 and circ-0008833-57aa. Results: Initially, we screened the expression profiles of human circRNAs in peripheral blood mononuclear cells of COPD patients, and found that has-circ-0008833 exhibited a significant increase in COPD mononuclear cells. Subsequently, we demonstrated that has-circ-0008833 carried an open reading frame (ORF), which encoded a functional protein, referred to as circ-0008833-57aa. By employing gain-of-function approaches, our results suggested that both circ-0008833 and circ-0008833-57aa inhibited proliferation, but accelerated the rate of 16HBE cell death. Finally, we discovered that circ-0008833 and circ-0008833-57aa promoted the expression of Caspase-1, IL-18, IL-1β, NLRP3, ASC, and cleaved GSDMD in 16HBE cells. Conclusions: Upregulation of circ-0008833 might promote COPD progression by inducing pyroptosis of bronchial epithelial cells through the encoding of a 57-amino acid peptide.

Circular RNAs: emerging players in asthma and COPD

Circular RNAs (circRNAs) belong to a unique class of endogenously expressed non-protein-coding RNAs with a distinct circularized structure, characterized by the absence of 5'-cap and 3'-polyadenylate ends. They are generally formed through back-splicing from pre-mRNAs. They serve as regulators of transcription and splicing, and act as sponges for microRNAs (miRNAs) and RNA-binding proteins, thereby modulating the expression of target genes. As a result, they exert a substantial impact on a diverse array of cellular and biological processes, including cell proliferation, migration, inflammation, and oxidative stress. Asthma and COPD are chronic airway conditions that currently have no cure. In recent years, emerging evidence suggests that altered expression of circRNAs in airway, bronchial and immune cells is involved in asthma and COPD pathogenesis. Studies exploring circRNA dysregulation in asthma have showcased their involvement in regulating the proliferation, migration, and inflammation of airway smooth muscle and bronchial epithelial cells, as well as impacting goblet cell metaplasia, Th2 cell differentiation, and macrophage activation, primarily through interactions with miRNAs. Similarly, in COPD, circRNAs have shown altered expression patterns in the blood and lungs of patients, and these changes have been linked to modulating inflammation, oxidative stress, and airway remodeling in preclinical models. Furthermore, certain circRNAs have demonstrated promising potential as diagnostic and prognostic biomarkers for both asthma and COPD. This review delves into the current understanding of the function and molecular mechanisms of circRNAs in asthma and COPD, along with exploring their potential as biomarkers in these respiratory conditions.

Circular RNAs: typical biomarkers for bone-related diseases

Bone is a connective tissue that has important functions in the human body. Cells and the extracellular matrix (ECM) are key components of bone and are closely related to bone-related diseases. However, the outcomes of conventional treatments for bone-related diseases are not promising, and hence it is necessary to elucidate the exact regulatory mechanisms of bone-related diseases and identify novel biomarkers for diagnosis and therapy. Circular RNAs (circRNAs) are single-stranded RNAs that form closed circular structures without a 5' cap or 3' tail and polycyclic adenylate tails. Due to their high stability, circRNAs have the potential to be typical biomarkers. Accumulating evidence suggests that circRNAs are involved in bone-related diseases, including osteoarthritis, osteoporosis, osteosarcoma, multiple myeloma, intervertebral disc degeneration, and rheumatoid arthritis. Herein, we summarize the recent research progress on the characteristics and functions of circRNAs, and highlight the regulatory mechanism of circRNAs in bone-related diseases.

Circ_0040929 Serves as Promising Biomarker and Potential Target for Chronic Obstructive Pulmonary Disease

Background

Circular RNAs (circRNAs) can act as essential regulators in many diseases, including chronic obstructive pulmonary disease (COPD). We aimed to explore the role and underlying mechanism of circ_0040929 in COPD.

Methods

A cellular model of COPD was constructed by treating human bronchial epithelial cells (16HBE) with cigarette smoke extract (CSE). The levels of circ_0040929, microRNA-515-5p (miR-515-5p) and insulin-like growth factor-binding protein 3 (IGFBP3) were measured by quantitative real-time PCR. Cell proliferation was assessed by Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell apoptosis was evaluated by flow cytometry. Protein expression was measured using Western blot assay. The levels of inflammatory factors and airway remodeling were assayed via enzyme-linked immunosorbent assay. The interaction between miR-515-5p and circ_0040929/IGFBP3 was confirmed by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation assays. Exosomes were detected using transmission electron microscopy.

Results

Circ_0040929 expression and IGFBP3 expression were upregulated in the serum of smokers (n = 22) compared to non-smokers (n = 22) and more significantly upregulated in the serum of COPD patients (n = 22). However, miR-515-5p expression was decreased in the serum of smokers compared to non-smokers and further reduced in the serum of COPD. Circ_0040929 knockdown attenuated CSE-induced cell injury by increasing proliferation and reducing apoptosis, inflammation, and airway remodeling in 16HBE cells. MiR-515-5p was a direct target of circ_0040929, and miR-515-5p inhibition reversed the effect of circ_0040929 knockdown in CSE-treated 16HBE cells. IGFBP3 was a direct target of miR-515-5p, and miR-515-5p overexpression alleviated CSE-induced cell injury via targeting IGFBP3. Moreover, circ_0040929 regulated IGFBP3 expression by targeting miR-515-5p. Importantly, circ_0040929 was upregulated in serum exosomes from COPD patients.

Conclusion

Circ_0040929 played a promoting role in CSE-induced COPD by regulating miR-515-5p/IGFBP3 axis, suggesting that it might be a novel potential target for COPD treatment.

Comprehensive identification of RNA transcripts and construction of RNA network in chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is one of the world’s leading causes of death and a major chronic disease, highly prevalent in the aging population exposed to tobacco smoke and airborne pollutants, which calls for early and useful biomolecular predictors. Roles of noncoding RNAs in COPD have been proposed, however, not many studies have systematically investigated the crosstalk among various transcripts in this context. The construction of RNA functional networks such as lncRNA-mRNA, and circRNA-miRNA-mRNA interaction networks could therefore facilitate our understanding of RNA interactions in COPD. Here, we identified the expression of RNA transcripts in RNA sequencing from COPD patients, and the potential RNA networks were further constructed.

Methods

All fresh peripheral blood samples of three patients with COPD and three non-COPD patients were collected and examined for mRNA, miRNA, lncRNA, and circRNA expression followed by qRT-PCR validation. We also examined mRNA expression to enrich relevant biological pathways. lncRNA-mRNA coexpression network and circRNA-miRNA-mRNA network in COPD were constructed.

Results

In this study, we have comprehensively identified and analyzed the differentially expressed mRNAs, lncRNAs, miRNAs, and circRNAs in peripheral blood of COPD patients with high-throughput RNA sequencing. 282 mRNAs, 146 lncRNAs, 85 miRNAs, and 81 circRNAs were differentially expressed. GSEA analysis showed that these differentially expressed RNAs correlate with several critical biological processes such as “ncRNA metabolic process”, “ncRNA processing”, “ribosome biogenesis”, “rRNAs metabolic process”, “tRNA metabolic process” and “tRNA processing”, which might be participating in the progression of COPD. RT-qPCR with more clinical COPD samples was used for the validation of some differentially expressed RNAs, and the results were in high accordance with the RNA sequencing. Given the putative regulatory function of lncRNAs and circRNAs, we have constructed the co-expression network between lncRNA and mRNA. To demonstrate the potential interactions between circRNAs and miRNAs, we have also constructed a competing endogenous RNA (ceRNA) network of differential expression circRNA-miRNA-mRNA in COPD.

Conclusions

In this study, we have identified and analyzed the differentially expressed mRNAs, lncRNAs, miRNAs, and circRNAs, providing a systematic view of the differentially expressed RNA in the context of COPD. We have also constructed the lncRNA-mRNA co-expression network, and for the first time constructed the circRNA-miRNA-mRNA in COPD. This study reveals the RNA involvement and potential regulatory roles in COPD, and further uncovers the interactions among those RNAs, which will assist the pathological investigations of COPD and shed light on therapeutic targets exploration for COPD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02069-8.

Peripheral blood circular RNA hsa_circ_0058493 as a potential novel biomarker for silicosis and idiopathic pulmonary fibrosis

Existing studies reported that some circular RNAs (circRNAs) play vital roles in the development of pulmonary fibrosis. However, few studies explored the biomarker potential of circRNAs for pulmonary fibrosis based on population data. Therefore, we aimed to identify peripheral blood circRNAs as potential biomarkers for diagnosing silicosis and idiopathic pulmonary fibrosis (IPF). In brief, an RNA-seq screening based on 4 silicosis cases and 4 controls was initially performed. Differentially expressed circRNAs were combined with the human serum circRNA dataset to identify overlapping serum-detectable circRNAs, followed by validation using the GEO dataset (3 IPF cases and 3 controls) and subsequent qRT-PCR, including 84 additional individuals. Following the above steps, 243 differentially expressed circRNAs were identified during the screening stage, with fold changes ≥ 1.5 and P < 0.05. Of note, the human serum circRNA dataset encompassed 28 of 243 circRNAs. GEO (GSE102660) validation revealed two highly expressed circRNAs (P < 0.05) in the IPF case group. Furthermore, at the enlarged sample validation stage, hsa_circ_0058493 was highly expressed in both silicosis and IPF cases (silicosis: P = 1.16 × 10^-6; IPF: P = 7.46 × 10^-5). Additionally, hsa_circ_0058493 expression was significantly increased in MRC-5 cells upon TGF-β1 treatment, while hsa_circ_0058493 knockdown inhibited the expression of fibrotic molecules by affecting the epithelial-mesenchymal transition process. These shreds of evidence indicated that hsa_circ_0058493 might serve as a novel biomarker for diagnosing silicosis and IPF.

Severity distribution and treatment of chronic obstructive pulmonary disease in China: baseline results of an observational study

Background

Chronic obstructive pulmonary disease (COPD) receives low awareness and is undertreated in China. Understanding the burden and treatment of COPD across the nation is important for improving quality of care for this disease. This study aims to reveal the current situation of COPD severity distribution and management across China.

Methods

Baseline data from REALizing and Improving Management of Stable COPD in China, a multicentre, prospective, longitudinal, observational study, were analysed. Patients diagnosed with COPD as per Global Initiative for Chronic Obstructive Lung Disease 2016 (GOLD 2016) criteria were enrolled from 50 randomly selected hospitals (tertiary, 25; secondary, 25) across six geographical regions. Data were collected in routine clinical settings.

Results

Between 15 December 2017 and 6 August 2020, 5013 patients were enrolled and 4978 included in the full analysis set. Of these, 2459 (49.4%) reported ≥ 1 exacerbation within 12 months prior to study enrolment, with a mean annual rate of 0.9/patient, including 0.2/patient and 0.5/patient leading to emergency room visits and hospitalisation, respectively. Spirometry graded 458 (10.1%), 1886 (41.7%), 1558 (34.5%), and 616 (13.6%) were GOLD stage I–IV, and 536 (11.4%), 1034 (22.0%), 563 (12.0%), and 2566 (54.6%) were classified as GOLD 2016 Group A–D, respectively, without evident regional variations. Inhaled corticosteroids plus long-acting beta₂-agonist (ICS/LABA, 1316 [26.4%]), ICS/LABA plus long-acting muscarinic antagonist (ICS/LABA + LAMA, 871 [17.5%]), and LAMA (754 [15.1%]) were prescribed at high rates across all groups and regions. Medications not recommended by GOLD were commonly prescribed (TCM, 578 [11.6%]; others, 951 [19.1%]), and 681 (13.7%) were not given ICS or long-acting bronchodilators.

Conclusions

Disease burden among Chinese COPD outpatients is high. Improved guideline adherence for COPD treatment is needed.

Trial registration ClinicalTrials.gov identifier, NCT03131362.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02021-w.

Integrative Studies of Human Cord Blood Derived Mononuclear Cells and Umbilical Cord Derived Mesenchyme Stem Cells in Ameliorating Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a common pulmonary complication observed in preterm infants that is composed of multifactorial pathogenesis. Current strategies, albeit successful in moderately reducing morbidity and mortality of BPD, failed to draw overall satisfactory conclusion. Here, using a typical mouse model mimicking hallmarks of BPD, we revealed that both cord blood-derived mononuclear cells (CB-MNCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) are efficient in alleviating BPD. Notably, infusion of CB-MNCs has more prominent effects in preventing alveolar simplification and pulmonary vessel loss, restoring pulmonary respiratory functions and balancing inflammatory responses. To further elucidate the underlying mechanisms within the divergent therapeutic effects of UC-MSC and CB-MNC, we systematically investigated the long noncoding RNA (lncRNA)-microRNA (miRNA)-messenger RNA (mRNA) and circular RNA (circRNA)-miRNA-mRNA networks by whole-transcriptome sequencing. Importantly, pathway analysis integrating Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG)/gene set enrichment analysis (GSEA) method indicates that the competing endogenous RNA (ceRNA) network is mainly related to the regulation of GTPase activity (GO: 0043087), extracellular signal-regulated kinase 1 (ERK1) and ERK2 signal cascade (GO: 0070371), chromosome regulation (GO: 0007059), and cell cycle control (GO: 0044770). Through rigorous selection of the lncRNA/circRNA-based ceRNA network, we demonstrated that the hub genes reside in UC-MSC- and CB-MNC-infused networks directed to the function of cell adhesion, motor transportation (Cdk13, Lrrn2), immune homeostasis balance, and autophagy (Homer3, Prkcd) relatively. Our studies illustrate the first comprehensive mRNA-miRNA-lncRNA and mRNA-miRNA-circRNA networks in stem cell-infused BPD model, which will be valuable in identifying reliable biomarkers or therapeutic targets for BPD pathogenesis and shed new light in the priming and conditioning of UC-MSCs or CB-MNCs in the treatment of neonatal lung injury.

CircANKRD11 Knockdown Protects HPMECs from Cigarette Smoke Extract-Induced Injury by Regulating miR-145-5p/BRD4 Axis

Background

Chronic obstructive pulmonary disease (COPD) is a major cause of death because of its high incidence and mortality, which is chiefly resulted from cigarette smoke exposure. A large number of studies show that circular RNA (circRNA) participates in regulating COPD process. This study aims to reveal the role of circRNA ankyrin repeat domain 11 (circANKRD11) in cigarette smoke extract (CSE)-induced cell apoptosis, inflammation, and oxidative stress.

Methods

The expression of circANKRD11, microRNA-145-5p (miR-145-5p) and bromodomain-containing 4 (BRD4) mRNA was detected by quantitative real-time polymerase chain reaction. The expression of apoptosis-related proteins and BRD4 protein was determined by Western blot. Cell apoptosis was detected by flow cytometry and Western blot. Cell inflammation was demonstrated by determining the levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) through enzyme-linked immunosorbent assay. Oxidative stress was investigated by the reactive oxygen species (ROS) and malondialdehyde (MDA) determination assays as well as superoxide dismutase (SOD) activity assay. The binding relationship between miR-145-5p and circANKRD11 or BRD4 was predicted by circinteractome or MicroT_CDS online database, and identified by dual-luciferase reporter, RNA immunoprecipitation or RNA pull-down assay.

Results

CircANKRD11 and BRD4 expression were increased, whereas miR-145-5p expression was decreased in the lung tissues of smokers with or without COPD and CSE-induced HPMECs compared with the lung tissues of non-smokers as well as untreated HPMECs, respectively. CircANKRD11 silencing ameliorated CSE-induced cell apoptosis, inflammation, and oxidative stress. CircANKRD11 acted as a sponge of miR-145-5p, and regulated CSE-induced cell injury via sponging miR-145-5p. Additionally, miR-145-5p mimics protected against CSE-induced cell injury through targeting BRD4.

Conclusion

CircANKRD11 absence protected HPMECs from CSE-induced injury by regulating BRD4 through associating with miR-145-5p, which demonstrated that circANKRD11 had the potential to act as a diagnosis biomarker for smoker-caused COPD.

Identification and Validation of Autophagy-Related Genes in Chronic Obstructive Pulmonary Disease

Purpose

Autophagy plays essential roles in the development of COPD. We aim to identify and validate the potential autophagy-related genes of COPD through bioinformatics analysis and experiment validation.

Methods

The mRNA expression profile dataset GSE38974 was obtained from GEO database. The potential differentially expressed autophagy-related genes of COPD were screened by R software. Then, protein–protein interactions (PPI), correlation analysis, gene-ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were applied for the differentially expressed autophagy-related genes. Finally, RNA expression of top five differentially expressed autophagy-related genes was validated in blood samples from COPD patients and healthy controls by qRT-PCR.

Results

A total of 40 differentially expressed autophagy-related genes (14 up-regulated genes and 26 down-regulated genes) were identified between 23 COPD patients and 9 healthy controls. The PPI results demonstrated that these autophagy-related genes interacted with each other. The GO and KEGG enrichment analysis of differentially expressed autophagy-related genes indicated several enriched terms related to autophagy and mitophagy. The results of qRT-PCR showed that the expression levels of HIF1A, CDKN1A, BAG3, ERBB2 and ATG16L1 in COPD patients and healthy controls were consistent with the bioinformatics analysis results from mRNA microarray.

Conclusion

We identified 40 potential autophagy-related genes of COPD through bioinformatics analysis. HIF1A, CDKN1A, BAG3, ERBB2 and ATG16L1 may affect the development of COPD by regulating autophagy. These results may expand our understanding of COPD and might be useful in the treatment of COPD.