Chronic Obstructive Pulmonary Disease Model Research Articles

Characterization of a spontaneous mouse model of mild, accelerated aging via ECM degradation in emphysematous lungs

Emphysema limits airflow and causes irreversible progression of chronic obstructive pulmonary disease (COPD). Strain differences must be considered when selecting mouse models of COPD, owing to disease complexity. We previously reported that a novel C57BL/6JJcl substrain, the Mayumi-Emphysema (ME) mouse, exhibits spontaneous emphysema; however, the other characteristics remain unknown. We aimed to characterize the lungs of ME mice and determine their experimental availability as a model. ME mice had a lower body weight than the control C57BL/6JJcl mice, with a median survival time of ~80 weeks. ME mice developed diffused emphysema with respiratory dysfunction from 8 to 26 weeks of age, but did not develop bronchial wall thickening. Proteomic analyses revealed five extracellular matrix-related clusters in downregulated lung proteins in ME mice. Moreover, EFEMP2/fibulin-4, an essential extracellular matrix protein, was the most downregulated protein in the lungs of ME mice. Murine and human EFEMP2 were detected in the pulmonary artery. Furthermore, patients with mild COPD showed decreased EFEMP2 levels in the pulmonary artery when compared to those without COPD. The ME mouse is a model of mild, accelerated aging with low-inflammatory emphysema and respiratory dysfunction that progresses with age and pulmonary EFEMP2 decrease, similar to that observed in patients with mild COPD.

Effects of elastase-induced emphysema on muscle and bone in mice.

Chronic obstructive pulmonary disease (COPD) causes sarcopenia and osteoporosis. However, the mechanisms underlying muscle and bone loss as well as the interactions between muscle and bone in the COPD state remain unclear. Therefore, we herein investigated the effects of the COPD state on muscle and bone in mice intratracheally administered porcine pancreatic elastase (PPE). The intratracheal administration of PPE to mice significantly reduced trabecular bone mineral density (BMD), trabecular bone volume, trabecular number, cortical BMD and cortical area. It also significantly decreased grip strength, but did not affect muscle mass or the expression of myogenic differentiation-, protein degradation- or autophagy-related genes in the soleus and gastrocnemius muscles. Among the myokines examined, myostatin mRNA levels in the soleus muscles were significantly elevated in mice treated with PPE, and negatively related to grip strength, but not bone parameters, in mice treated with or without 2 U PPE in simple regression analyses. Grip strength positively related to bone parameters in mice treated with or without PPE. In conclusion, we showed that a PPE model of COPD in mice exerts dominant effects on bone rather than skeletal muscles. Increased myostatin expression in the soleus muscles of mice in the COPD state may negatively relate to a reduction in grip strength, but not bone loss.

Butyrate inhibits iILC2-mediated lung inflammation via lung-gut axis in chronic obstructive pulmonary disease (COPD)

BackgroundThe study investigated the effects and underlying mechanisms of intestinal flora metabolite butyrate on inflammatory ILC2 cells (iILC2s)-mediated lung inflammation in chronic obstructive pulmonary disease (COPD).MethodsMouse models of COPD and acute exacerbation of COPD (AECOPD) were established. Flow cytometry was used to detect natural ILC2 cells (nILC2s) and iILC2s in lung and colon tissues. The 16s rRNA and GC-MS were used to detect microbial flora and short chain fatty acids (SCFAs) in feces. ELISA was used to detect IL-13 and IL-4. Western blot and qRT-PCR were used to detect the relative protein and mRNA levels, respectively. In vitro experiments were performed with sorted ILC2s from colon tissues of control mice. Mice with AECOPD were treated with butyrate.ResultsThe nILC2s and iILC2s in lung and colon tissues of AECOPD mice were significantly higher than control groups. The abundance of the flora Clostridiaceae was significantly reduced, and the content of SCFAs, including acetate and butyrate, was significantly reduced. The in vitro experiments showed that butyrate inhibited iILC2 cell phenotype and cytokine secretion. Butyrate treatment reduced the proportion of iILC2 cells in the colon and lung tissues of mice with AECOPD.ConclusionsThe nILC2s and iILC2s in the colon tissues are involved in the course of COPD. Decreased Clostridiaceae and butyrate in AECOPD mice caused the accumulation of iILC2 cells in the intestines and lungs. Supplementation of butyrate can reduce iILC2 in the intestine and lung tissues. Our data may provide new ideas for prevention and treatment of COPD.

Mettl3 Mediated m6A Methylation Involved in Epithelial-Mesenchymal Transition by Targeting SOCS3/STAT3/SNAI1 in Cigarette Smoking-Induced COPD.

Persistent inflammation and epithelial-mesenchymal transition are essential pathophysiological processes in chronic obstructive pulmonary disease (COPD) and involve airway remodeling. m6A methylation modification was discovered to play an important role in various diseases. Nevertheless, the regulatory role of m6A methylation has not yet been investigated in cigarette smoking-induced COPD. The study aims to explore the regulatory role of m6A methylation in cigarette smoking-induced COPD. In this study, two Gene Expression Omnibus (GEO) datasets were first utilized to analyze the expression profiles of m6A RNA methylation regulators in COPD. We then established a cell model of COPD by exposing human bronchial epithelial cells (HBECs) to cigarette smoke extract (CSE) in vitro and detected the expression of m6A writer Mettl3 and EMT phenotype markers. RNA interference, cycloleucine, RT-qPCR, western blot, MeRIP-sequencing, and cell migration assay were performed to investigate the potential effect of Mettl3 on the EMT process in CSE-induced HBECs. Our results showed that Mettl3 expression was significantly elevated in cigarette smoking-induced COPD patients and in a cellular model of COPD. Furthermore, Mettl3 silence and cycloleucine treatment inhibited the EMT process of HBECs caused by CSE. Mechanically, Mettl3 silence weakens the m6A methylation of SOCS3 mRNA to enhance the protein expression of SOCS3, inhibiting CSE-induced SOCS3/STAT3/SNAI1 signaling and EMT processes in HBECs. Our study inferred that Mettl3-mediated m6A RNA methylation modification modulates CSE-induced EMT by targeting SOCS3 mRNA and ultimately serves as a crucial regulator in the emergence of COPD. This conclusion reinforces the regulatory role of m6A methylation in COPD.

Prolonged intermittent hypoxia causes mitochondrial dysfunction due to O-GlcNacylation of DRP1 in models of COPD (chronic obstructive pulmonary disease)

Background: Sarcopenia, or skeletal muscle loss, is common complication in COPD and contributes to adverse clinical outcomes including mortality. As the disease progresses, a significant proportion of COPD patients develop nocturnal hypoxemia which causes tissue-level hypoxia in the skeletal muscle which we have termed prolonged intermittent hypoxia (PIH). We have demonstrated sarcopenia, mitochondrial dysfunction, and dysregulated hypoxia-inducible factor 1-α (HIF1-α) responses both in vitro and in vivo in response to PIH. We also noted multiple transcriptional targets of HIF1-α were upregulated in the glycolytic pathway. We hypothesized that PIH upregulates the Hexosamine Biosynthetic (HB) pathway, a branch of glycolysis responsible for post-translational glycosylation of proteins, to cause O-GlcNAcylation of DRP1 leading to increased mitochondrial fission, fragmented mitochondrial networks, mitochondrial dysfunction, and sarcopenia. Methods: Our in vitro model of PIH exposed differentiated, murine C2C12 myotubes to 16h normoxia/8h hypoxia [1% oxygen] for 3 days, while our in vivo model exposed C57BL/6 mice to 12h normoxia/12h hypoxia [10% oxygen] for 21 days. Protein extraction and immunoblots were performed to probe for enzymes in the HB, mTORC1 pathways, O-GlcNAcylation, and puromycin incorporation. Imaging of mitochondrial structure was determined by staining with MitoTracker orange and electron microscopy. Immunoprecipitation and detection of Drp1 O-GlcNAcylation was performed by incubating protein lysates with Wheat Germ Agglutinin coated Agarose beads. To determine responses to inhibition of O-GlcNAcylation, we performed CRISPR-Cas9 RNP deletion of GFAT, the first enzyme in the HB pathway. Results: We found significant increase in O-GlcNAcylated proteins in our PIH models . This was accompanied by increased expression of HIF1-α, mitochondrial dysfunction, and upregulated enzymes in the HB pathway. O-GlcNAcylated modification of DRP1 was significantly upregulated due to PIH in vitro. GFAT KO myotubes demonstrated significant reductions in global O-GlcNAcylation of proteins and O-GlcNAcylated Drp1 with PIH. Interestingly, protein synthesis was rescued in GFAT KO myotubes as determined by puromycin incorporation, restoration of mTORC1 signaling, and reversal of a sarcopenic phenotype. Conclusion: Our findings demonstrate a potential mechanism for mitochondrial dysfunction and sarcopenia due to PIH which may be translationally relevant for patients with COPD. Future studies focused on O-GlcNAcylated modification of DRP1 and the functional consequences are needed to identify novel therapeutic targets to reverse sarcopenia in COPD. Supported in part by: NIH RO1 GM119174; RO1 DK113196; P50 AA024333; RO1 AA021890; 3U01AA026976 - 03S1; UO1 AA 026976; R56HL141744;UO1 DK061732; 5U01DK062470-17S2; R21 AR 071046; Howard and Helen Trevey Endowment; (SD); K12 HL141952 (AA) and the American College of Gastroenterology Clinical Research Award and NIH KO8 AAAA028794 (NW). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Changes in targeted metabolomics in lung tissue of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a common chronic lung disease and its incidence is steadily increasing. COPD patients and mouse models of COPD share some similarities in lung pathology and physiology. We performed this study to explore the potential metabolic pathways involved in the pathogenesis of COPD and to discover the COPD-associated biomarkers. Furthermore, we aimed to examine how much the mouse model of COPD was similar and different to human COPD in terms of the altered metabolites and pathways. Twenty human lung tissue samples (ten COPD and ten controls) and twelve mice lung tissue samples (six COPD and six controls) were analyzed by targeted HM350 metabolomics, and multivariate and pathway analysis were performed by Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The counts of many metabolites such as amino acids, carbohydrates and carnitines were changed in both COPD patients and mice compared to controls, respectively. While lipid metabolism was changed only in COPD mice. After KEGG analysis, we found these altered metabolites involved in COPD through aging, apoptosis, oxidative stress and inflammation pathways. The expressions of metabolites changed in both COPD patients and cigarette smoke exposed (CS-exposed) mice. And there were also some differences between COPD patients and mouse models due to the differences between species. Our study suggested the dysregulation in amino acid metabolism, energy production pathway and perhaps lipid metabolism may be significantly related to the pathogenesis of COPD.

EPC-exosomal miR-26a-5p improves airway remodeling in COPD by inhibiting ferroptosis of bronchial epithelial cells via PTGS2/PGE2 signaling pathway

We aimed to investigate whether exosomes (Exo) affected chronic obstructive pulmonary disease (COPD) by influencing ferroptosis of bronchial epithelial cells (BECs) and the mechanisms involved. Here we took the peripheral blood samples of normal subjects and COPD patients, extracted and identified endothelial progenitor cells (EPCs) and EPC-Exo. An animal model of COPD was established. Then human BECs were taken and treated with cigarette smoke extract (CSE) for 24 h to construct a COPD cell model. Next, we screened differentially expressed ferroptosis-related genes in COPD patients by bioinformatics. Bioinformatics predicted the miRNA targeting PTGS2. Then, the mechanism of action of miR-26a-5p and Exo-miR-26a-5p was investigated in vitro. We successfully isolated and identified EPC and Exo. In vitro, EPC alleviated CSE-induced ferroptosis in BECs by transporting Exo. In vivo, Exo alleviated cigarette smoke-induced ferroptosis and airway remodeling in mice. Through further validation, we found that CSE-induced ferroptosis promoted the epithelial-mesenchymal transition (EMT) of BECs. Bioinformatics analysis and validation showed that PTGS2/PGE2 pathway affected CSE-induced ferroptosis in BECs. Meanwhile, miR-26a-5p targeting PTGS2 affected CSE-induced ferroptosis in BECs. Additionally, we found that miR-26a-5p affected CSE-induced BECs EMT. Exo-miR-26a-5p alleviated CSE-induced ferroptosis and EMT. In conclusion, EPC-exosomal miR-26a-5p improved airway remodeling in COPD by inhibiting ferroptosis of BECs via the PTGS2/PGE2 pathway.

Dental Pulp Stem Cells Ameliorate Elastase-Induced Pulmonary Emphysema by Regulating Inflammation and Oxidative Stress.

Dental pulp stem cells (DPSCs) are considered excellent candidates for stem cell-based tissue regeneration. In this study, we aimed to evaluate the therapeutic effect of DPSCs in a mouse chronic obstructive pulmonary disease (COPD) model and to explore whether DPSCs reduce lung inflammation and oxidative stress by regulating the nuclear factor erythroid-2 related factor-2 (Nrf2) signaling pathway. DPSCs were isolated from dental pulp tissue by the tissue block method. Emphysema of C57BL/6 mice was induced by endotracheal administration of porcine pancreatic elastase (PPE). Then, the DPSCs were injected into the lungs through the trachea, and after 3 weeks of stem cell treatment, various efficacy tests were performed. The AniRes2005 animal lung function analytic system was used to detect lung function. Hematoxylin-eosin staining (H&E) and Victoria blue staining was used to assess emphysema severity. The animal tissues were detected by Western blot, RT‒qPCR, ELISA and oxidative stress related detection. In experimental COPD models, DPSCs transplantation improved lung function, body weight, and emphysema-like changes better than bone marrow mesenchyml stem cells (BM-MSCs). Compared with the COPD group, the levels of IL-1β, TNF-α and IL-6 in lung tissue and bronchoalveolar lavage fluid (BALF) were decreased after transplantation of DPSCs. DPSCs may be associated with lower malondialdehyde (MDA) levels, and higher catalase (CAT) and glutathione (GSH) levels. Western blot results showed that the expression of Nrf2 and its downstream factors increased after transplantation of DPSCs. The current study showed that DPSCs had good performance in the treatment of a mouse COPD model and could be a promising option for stem cell therapy. DPSCs may play antioxidant and anti-inflammatory roles in COPD by activating the Nrf2 signaling pathway.

Yinyanghuo () and its components for chronic obstructive pulmonary disease: preclinical evidence and possible mechanisms.

To integrate Meta-analysis and bioinformatics strategies in the preliminary exploration of the potential mechanism of Yinyanghuo () and its extract in treating chronic obstructive pulmonary disease (COPD). First, Meta-analysis was carried out. The Chinese and English literature of Yinyanghuo () in treating COPD was searched using the systematic strategy of combining subject words with free words. The included studies were evaluated by the SYRCLE risk bias assessment tool, after which the review manager software was used to combine the effect quantities for statistical analysis. Then, based on bioinformatics technology, the active ingredients and their targets of Yinyanghuo () were screened, and the intersection genes were obtained by mapping and comparing with the targets of COPD. The "medicinal materials-compounds-targets model" was constructed, and the key pathways were annotated. Finally, the core target was docked with important compounds. A total of 8 studies were included in the Meta-analysis. The results showed that the Yinyanghuo (Herba Epimedii Brevicornus) group could significantly down-regulate pro-inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-8 and increase the expression of anti-inflammatory factors and antioxidant factors such as IL-10 and phospho-protein kinase B (p-AKT) in the COPD model (all P < 0.05). A total of 23 active components and 102 corresponding target genes of Yinyanghuo (Herba Epimedii Brevicornus) were obtained by bioinformatics technology, among which 17 compounds and 63 targets were closely related to COPD. The results of enrichment analysis mainly included TNF signaling pathway, phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, cancer signaling pathway, and other inflammatory reactions, oxidative stress, and tumor-related pathways. The molecular docking results showed that the binding energy fractions of the top five components of 24-epicampesterol with 10 core targets such as IL-6 were all less than ﹣5.0 kcal/mol, suggesting good binding ability. Meta-analysis and bioinformatics results indicated that the therapeutic effect of Yinyanghuo () and its components on COPD might be related to antagonizing inflammation and oxidative stress. The above findings provide a preliminary basis for the development of Yinyanghuo () as a natural drug for preventing and treating COPD.

Dental Pulp Stem Cell-Derived Exosomes Inhibit Senescence-Induced Chronic Obstructive Pulmonary Disease Through the Nuclear Factor Kappa B Signaling Pathway

The respiratory condition known as chronic obstructive pulmonary disease (COPD) is widespread, but its pathogenesis remains unclear. To investigate the mechanism by which dental pulp stem cells (DPSCs) and their exosomes inhibit cellular senescence, senescence was first induced in bronchial epithelial cells by treatment with 5% cigarette smoke extract (5% CSE). Our results revealed that the senescence of bronchial epithelial cells induced by 5% CSE was decreased when co-cultured with dental pulp stem cells or their exosomes. Furthermore, this study identified that 5% CSE promoted cell senescence through the Nuclear factor kappa B (NF-kB) pathway. In addition, 5% CSE-induced cell senescence was limited when IKKβ was knocked out in bronchial epithelial cells. Meanwhile, DPSCs inhibited cell senescence through exosomal-MALAT1. Contrastingly, this effect was reversed by MALAT1 knockout. In the mouse COPD model, it was found that DPSCs could effectively inhibit COPD progression via reducing cell senescence-related proteins in mouse lung tissues, such as p21 and GLB1, and upregulating the MALAT1 expression. TNF-α and p21 expression levels were considerably reduced after treatment with dental pulp stem cells, according to IHC staining. Finally, we validated that DPSCs and their exosomes inhibit cell senescence by regulating MALAT1 and the NF-kB pathway in vitro as well as in vivo, thereby exerting a therapeutic effect in COPD.

Luteolin suppresses inflammation and oxidative stress in chronic obstructive pulmonary disease through inhibition of the NOX4‐mediated NF‐κB signaling pathway

Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation that predominantly affects the lung and peripheral airways. Previous investigation has underlined the efficacy of luteolin in the treatment of inflammation-related symptoms. Accordingly, our study concentrates on unveiling the effect of luteolin on COPD. Mice or A549 cells were treated with cigarette smoke (CS) to establish COPD models in vivo and in vitro. Then, the serum and bronchoalveolar lavage fluidof mice were harvested. The lung tissues of mice were subjected to hematoxylin-eosin staining to observe the degree of damage. The inflammation and oxidative stress factors level were calculated via enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction. The expressions of nuclear factor-kappa B (NF-κB) pathway-related factors were detected by Western blot. In in vivo experiments, CS treatment reduced the weight of mice and promoted lung tissue damage, while luteolin attenuated the effect of CS on the mice. Moreover, luteolin inhibited the inflammation factors level, oxidative stress, and NADPH oxidase 4 (NOX4)-mediated NF-κB signaling pathway in CS-induced COPD mice. Similar results were obtained in in vitro experiments that luteolin alleviated CS-induced inflammation, oxidative stress, and NOX4-mediated NF-κB signaling pathway activation in CS-treated A549 cells. Besides, NOX4 overexpression offset the impacts of luteolin on the CS-induced A549 cells. Luteolin alleviates inflammation and oxidative stress in COPD via NOX4-mediated NF-κB signaling pathway, which provides a theoretical basis for the treatment of COPD with luteolin.

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.

Integrating RNA-seq and scRNA-seq to explore the mechanism of macrophage ferroptosis associated with COPD.

Aims: Our study focused on whether macrophages ferroptosis is associated with the pathogenesis of chronic obstructive pulmonary disease (COPD) or not. Main methods: We first identified macrophage module genes by weighted gene co-expression network analysis (WGCNA) in RNA sequencing (RNA-seq) date from COPD, and then identified macrophage marker genes by comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data from COPD macrophages. There were 126 macrophage marker genes identified, and functional enrichment analyses indicated that ferroptosis pathway genes were significantly enriched. Secondly, we identified eight macrophage ferroptosis related genes and based on these eight genes, we performed co-expression analysis and drug prediction. Thirdly, two biomarkers (SOCS1 and HSPB1) were screened by the least absolute shrinkage and selection operator (LASSO), random forest (RF), and support vector machine-recursive feature elimination (SVM-RFE) and established an artificial neural network (ANN) for diagnosis. Subsequently, the biomarkers were validated in the dataset and validation set. These two biomarkers were then subjected to single gene-gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) analysis, and the ceRNA network was constructed. Finally, we carried out molecular validation with COPD models in vitro for cell counting kit-8 (CCK8) experiments, Western blot and quantitative real-time PCR (qRT-PCR) analysis and transmission electron microscopy (TEM). Key findings: This study revealed the vital role of macrophage ferroptosis in COPD, and novel biomarkers (SOCS1 and HSPB1) may be involved in the pathogenesis of COPD by regulating macrophage ferroptosis. Significance: Taken together, our results suggest that targeting SOCS1 and HSPB1 could treat COPD by inhibiting macrophage ferroptosis.

Atrophy signaling pathways in respiratory and limb muscles of guinea pigs exposed to chronic cigarette smoke: role of soluble guanylate cyclase stimulation.

Skeletal muscle dysfunction in chronic obstructive pulmonary disease (COPD) is characterized by a significant reduction in muscle strength and endurance. Preclinical studies show that stimulation of the soluble guanylate cyclase (sGC)-cGMP pathway attenuates muscle mass loss and prevents cigarette smoke-induced oxidative stress, indicating that pharmacological activation of the guanylyl cyclase pathway in COPD may provide a beneficial therapeutic strategy that reaches beyond the lung. In this study, conducted in an animal model of COPD, we first set out to assess the effect of cigarette smoke (CS) on biomarkers of muscle fatigue, such as protein degradation and its transcriptional regulation, in two types of muscles with different energy demands, i.e., the diaphragm and the gastrocnemius muscle of the limbs. Second, we evaluated the administration of an sGC stimulator on these markers to study the potential efficacy of such treatment in the recovery of skeletal muscle function. Exposure to CS led to weight loss, which was associated in the gastrocnemius with increased levels of proteolytic markers of muscle atrophy (MURF-1, Atrogin-1, proteasome C8 subunit 20 s, and total protein ubiquitination), whereas the size of fast-twitch muscle fibers decreased significantly. Long-term treatment with the sGC stimulator BAY 41-2272 resulted in a significant reduction in gastrocnemius levels of the aforementioned proteolytic markers, concomitant with a weight recovery and increased cGMP levels. Remarkably, levels of some of the analyzed biomarkers differed between respiratory and limb muscles. In conclusion, targeting sGC might exert beneficial effects on muscle alterations in patients with COPD.

N6-Methyladenosine-modified circSAV1 triggers ferroptosis in COPD through recruiting YTHDF1 to facilitate the translation of IREB2.

Epithelial cell damage-initiated chronic obstructive pulmonary disease (COPD) is implicated in regulated cell death (RCD) including ferroptosis triggered by complex gene-environment interactions. Our data showed that iron overload and ferroptosis are associated with COPD progression in COPD patients and in experimental COPD. Furthermore, we found that, in lung tissues of COPD patients, circSAV1 was associated with COPD progression by circRNA-seq screening. Knockdown of circSAV1 reversed cigarette smoke extract (CSE)-induced ferroptosis. Mechanistically, m6A-modified circSAV1 formed an RNA-protein ternary complex of circSAV1/YTHDF1/IREB2 to facilitate the translation of IREB2 mRNA. Elevated protein levels of IREB2 disrupted iron homeostasis, resulting in accumulation of a labile iron pool (LIP) and lipid peroxidation, which contribute to ferroptosis. Here we demonstrate, by use of an experimental COPD model induced by cigarette smoke (CS), that silencing of circSAV1 and the treatment with deferoxamine (DFO) blocked CS-induced ferroptosis of lung epithelial cells, which attenuated COPD progression in mice. Our results reveal that N6-methyladenosine-modified circSAV1 triggers ferroptosis in COPD through recruiting YTHDF1 to facilitate the translation of IREB2, indicating that circSAV1 is a mediator of ferroptosis and that circSAV1-dependent ferroptosis is a therapeutic target for COPD. In lung epithelial cell, m6A-modified circSAV1, via recruiting YTHDF1, induces the formation of a circSAV1/YTHDF1/IREB2 mRNA protein ternary complex, which promotes translation of IREB2 mRNA. Further, elevated IREB2 contributes to the accumulation of a labile iron pool (LIP) and lipid peroxidation, then triggers ferroptosis of lung epithelial cells. The ferroptosis of airway epithelial cells and alveolar epithelial cells induces airway remodeling and emphysema, respectively, which causes COPD.

Logistic Regression Analysis of Clinical Characteristics for Differentiation of Chronic Obstructive Pulmonary Disease Severity.

This study aimed to investigate the predictive value of general clinical data, blood test indexes, and ventilation function test indexes on the severity of chronic obstructive pulmonary disease (COPD). A total of 141 clinical characteristics of COPD patients admitted to our hospital were collected. A mild-to-moderate group and a severe group were classified depending on the severity of COPD, and their baseline data were compared. The predictive factors of severe COPD were analyzed by univariate and multivariate logistic regression, and the nomogram model of severe COPD was constructed. The clinical variables, including gender, height, weight, body mass index (BMI), age, course, diabetes, hypertension, smoking history, WBC, NEUT, lymphocyte count (LY), MONO, eosinophil count (EOS), PLT, mean platelet volume (MPV), platelet distribution width (PDW), partial pressure of oxygen (PaO2), and PaCO2, were collected. There were 67 mild-to-moderate COPD patients and 74 severe COPD patients in this study cohort. Severe COPD had a higher white blood cell count (WBC), neutrophil count (NEUT), monocyte count (MONO), platelet count (PLT), neutrophil to lymphocyte ratio (NLR), and a lower partial pressure of carbon dioxide (PaCO2). Univariate logistic regression analysis showed that WBC, NEUT, MONO, PLT, and NLR were contributing factors of severe COPD, while PaCO2 was an unfavorable factor of severe COPD. Enter, forward, backward, and stepwise multivariate logistic regression analyses all showed that NEUT and PLT were independent contributing factors to severe COPD. Moreover, the nomogram model had good predictive ability, with an area under the curve (AUC) of the receiver operating characteristic (ROC) curve being 0.881. Good calibration and clinical utility were validated through the calibration plot and the decision curve analysis (DCA) plot, respectively. The severity of COPD was correlated with NEUT and PLT, and the nomogram model based on these factors had good predictive performance.

Relationship Between ACSL4-Mediated Ferroptosis and Chronic Obstructive Pulmonary Disease.

Although cigarette smoke exposure is the major risk factor for chronic obstructive pulmonary disease (COPD), the mechanism is not completely understood. The aim of the present study was to investigate whether ACSL4-mediated ferroptosis in lung epithelial cells plays a part in the COPD development process and its association. In this study, animal and cell models of COPD were modelled using cigarette smoke extracts (CSEs), and cell viability, lipid ROS, iron ion deposition, and ferroptosis-related markers were measured in lung tissue and lung epithelial cells following CSE exposure. Morphological changes in mitochondria were observed in lung tissue and epithelial cells of the lung by transmission electron microscope. The expression levels of ACSL4 mRNA and protein in lung tissue and epithelial cells were measured by real-time PCR and Western blotting. In addition, animal-interfering lentivirus and cell-interfering RNA against ACSL4 were constructed in this study, ferroptosis in lung tissue and lung epithelial cells after ACSL4 interference was detected, and ACSL4 mRNA and protein expression levels were detected. CSE induced ferroptosis in lung tissues and lung epithelial cells, and the expression levels of ACSL4 were elevated in CSE-treated lung tissues and lung epithelial cells. After ACSL4 interference, the expression of ACSL4 decreased, mitochondrial morphology was restored, and ferroptosis in lung tissues and lung epithelial cells was alleviated. Both respiratory frequency and enhanced pause of COPD mice models decreased after ACSL4 interference. ACSL4-mediated ferroptosis in lung epithelial cells is associated with COPD and positively correlated with ferroptosis in epithelial cells.

Effects of Cheonwangbosim-dan in a Mouse Model of Chronic Obstructive Pulmonary Disease: Anti-Inflammatory and Anti-Fibrotic Therapy

Chronic obstructive pulmonary disease (COPD) is a lung illness, marked by dyspnea, coughing, and sputum production. Cheonwangbosim-dan (CBD) is a traditional East Asian medicine, consisting of a combination of 15 medicinal herbs, which is frequently used to treat arterial/auricular flutter, neuroses, cardiac-malfunction-induced diseases, and insomnia. The present study evaluated the therapeutic effect of CBD (100 or 200 mg/kg) on COPD using a mouse model of COPD induced by cigarette smoke (CS) and lipopolysaccharide (LPS). The increase in inflammatory cell numbers caused by exposure to CS and LPS was significantly reduced by CBD administration. In addition, CBD therapy reduced interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in bronchoalveolar lavage fluid (BALF). In lung tissue, CBD not only reduced the levels of IL-1β (CBD 100: p &lt; 0.001 and CBD 200: p &lt; 0.001), IL-6 (CBD 100: p &lt; 0.001 and CBD 200: p &lt; 0.001), TNF-α (CBD 100: p = 0.005 and CBD 200: p = 0.014), and monocyte chemoattractant protein-1 (MCP-1; CBD 100: p = 0.018 and CBD 200: p = 0.003), but also decreased the expression of α-smooth muscle actin (α-SMA; CBD 100: p &lt; 0.001 and CBD 200: p &lt; 0.001), transforming growth factor-β (TGF-β; CBD 100: p &lt; 0.001 and CBD 200: p &lt; 0.001), matrix metallopeptidase-7 (MMP-7; CBD 100: p = 0.019 and CBD 200: p &lt; 0.001), MMP-9 (CBD 100: p = 0.015 and CBD 200: p = 0.013), and tissue inhibitor of metalloproteinase-1 (TIMP-1; CBD 100: p = 0.035 and CBD 200: p = 0.013) compared with the COPD group. CBD was also found to suppress the phosphorylation of nuclear factor kappa B (NF-κB), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinases (p38 MAPK). Taken together, these findings showed that CBD can attenuate respiratory inflammation and airway remodeling induced by exposure to CS and LPS, suggesting that CBD has probable preventive and therapeutic applications in patients with COPD.

Potential of hydroethanolic leaf extract of Ocimum sanctum in ameliorating redox status and lung injury in COPD: an in vivo and in silico study

Oxidative stress and inflammation are hypothesised as the main contributor for Chronic Obstructive Pulmonary Disease (COPD). Cigarette smoke (CS), a major cause of COPD leads to inflammation resulting in recruitment of neutrophils and macrophages which are rich sources of oxidants. Activation of these cells produces excess oxidants and depletes antioxidants resulting in stress. Presently, effective drug for COPD is limited; therefore, novel compounds from natural sources, including plants are under exploration. The present study aims to investigate the protective effect of Ocimum sanctum leaf extract (OLE) in CS − induced model of COPD. Exposure to CS was performed thrice a week for 8 weeks and OLE (200 mg/kg and 400 mg/kg) was administered an hour before CS exposure. Control group (negative control) were exposed to ambient air while COPD group was exposed to CS (positive control). Administration of OLE doses reduced inflammation, decreased oxidant concentration and increased antioxidant concentration (p < 0.01). Molecular docking studies between the major phytocompounds of OLE (Eugenol, Cyclohexane and Caryophyllene) and antioxidant enzymes Superoxide dismutase (SOD), Catalase, Glutathione peroxidase (GPx), Glutathione reductase (GR) and Glutathione S Transferase (GST) showed strong binding interaction in terms of binding energy. In vivo and in silico findings for the first time indicates that OLE extract significantly alleviates oxidative stress by its potent free radical scavenging property and strong interaction with antioxidant enzymes. OLE extract may prove to be a therapeutic option for COPD prevention and treatment.

Associative analysis of multi-omics data indicates that acetylation modification is widely involved in cigarette smoke-induced chronic obstructive pulmonary disease.

We aimed to study the molecular mechanisms of chronic obstructive pulmonary disease (COPD) caused by cigarette smoke more comprehensively and systematically through different perspectives and aspects and to explore the role of protein acetylation modification in COPD. We established the COPD model by exposing C57BL/6J mice to cigarette smoke for 24 weeks, then analyzed the transcriptomics, proteomics, and acetylomics data of mouse lung tissue by RNA sequencing (RNA-seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), and associated these omics data through unique algorithms. This study demonstrated that the differentially expressed proteins and acetylation modification in the lung tissue of COPD mice were co-enriched in pathways such as oxidative phosphorylation (OXPHOS) and fatty acid degradation. A total of 19 genes, namely, ENO3, PFKM, ALDOA, ACTN2, FGG, MYH1, MYH3, MYH8, MYL1, MYLPF, TTN, ACTA1, ATP2A1, CKM, CORO1A, EEF1A2, AKR1B8, MB, and STAT1, were significantly and differentially expressed at all the three levels of transcription, protein, and acetylation modification simultaneously. Then, we assessed the distribution and expression in different cell subpopulations of these 19 genes in the lung tissues of patients with COPD by analyzing data from single-cell RNA sequencing (scRNA-seq). Finally, we carried out the in vivo experimental verification using mouse lung tissue through quantitative real-time PCR (qRT-PCR), Western blotting (WB), immunofluorescence (IF), and immunoprecipitation (IP). The results showed that the differential acetylation modifications of mouse lung tissue are widely involved in cigarette smoke-induced COPD. ALDOA is significantly downregulated and hyperacetylated in the lung tissues of humans and mice with COPD, which might be a potential biomarker for the diagnosis and/or treatment of COPD.