Role of p38-mitogen-activated protein kinase in COPD: pathobiological implications and therapeutic perspectives

Integrated network pharmacology, molecular docking, and animal experiments to reveal the potential mechanism of hesperetin on COPD

Hesperetin (HE), a natural flavonoid exhibiting anti-inflammatory and antioxidant properties, holds significant potential in treating chronic obstructive pulmonary disease (COPD). Nonetheless, the precise mechanisms underlying its effects are yet to be fully elucidated. In this study, we aim to explore the role and potential mechanism of HE in treating COPD using network pharmacology, molecular docking and experimental validation. We screened for HE and COPD-related targets from public databases, and then imported potential targets into a STRING database to establish a protein-protein interaction network. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes enrichment analysis were performed to obtain key signaling pathways. We then predicted the binding interactions between HE and core targets using molecular docking. The animal model of COPD was established through lipopolysaccharide and cigarette smoke induction in mice to observe lung function, inflammatory factors, pathology, and the expression of related proteins. Network pharmacology findings unveiled that HE and COPD shared 105 common targets. MAPKs and NF-κB signaling pathways were selected for further validation. In animal experiment, HE enhanced lung function and histopathological morphology, while reducing inflammation levels. The results of Western blot tests indicated that HE treatment considerably inhibited the expression of MAPKs and NF-κB. HE effectively reduced lung inflammation and improved lung function in mice. This mechanism may be achieved by inhibition of MAPKs and NF-κB signaling pathways.

Mechanisms coupling the mTOR pathway to chronic obstructive pulmonary disease (COPD) pathogenesis

Chronic Obstructive Pulmonary Disease (COPD) is a poorly reversible respiratory disorder distinguished by dyspnea, cough, expectoration and exacerbations due to abnormality of airways or emphysema. In this review, we consider the therapeutic potential of targeting Mammalian target of Rapamycin (mTOR) for treating COPD. The mTOR is a highly conserved serine-threonine protein kinase that integrates signals from growth factors and nutrients to control protein synthesis, lipid biogenesis and metabolism. Dysregulated mTOR pathway signaling due to genetic factors or cigarette smoking impairs autophagy, driving the buildup of abnormal cells and damaged proteins, resulting in inflammation and oxidative stress. Persistent mTOR activation also contributes to pulmonary vascular cell proliferation, facilitating the development of pulmonary resistance in COPD. Rapamycin, an inhibitor of mTOR, prevents the buildup of senescent cells in the lungs of COPD patients and inhibits the release of lung tissue-damaging proteases. mTOR also impacts the corticosteroid sensitivity in COPD patients by regulating the levels of histone deacetylases. The emerging role of gut-lung axis dysbiosis in the progression of COPD and its influence on mTOR further highlights the relevance of the mTOR pathway in COPD pathophysiology.

Peripheral blood miRNAs are associated with airflow below threshold in children with asthma

BACKGROUND

MicroRNAs (miRNAs) are crucial post-transcriptional regulators involved in inflammatory diseases, such as asthma. Poor lung function and airflow issues in childhood are linked to the development of chronic obstructive pulmonary disease (COPD) in adulthood.

METHODS

We analyzed small RNA-Seq data from 365 peripheral whole blood samples from the Genetics of Asthma in Costa Rica Study (GACRS) for association with airflow levels measured by FEV1/FVC. Differentially expressed (DE) miRNAs were identified using DESeq2 in R, adjusting for covariates and applying a 10% false discovery rate (FDR). The analysis included 361 samples and 649 miRNAs. The two DE miRNAs were further tested for association with airflow obstruction in a study of adult former smokers with and without COPD.

RESULTS

We found 1 upregulated and 1 downregulated miRNA in participants with airflow below the threshold compared to those above it. In the adult study, the same miRNAs were upregulated and downregulated in individuals with FEV1/FVC < 0.7 versus those with FEV1/FVC > 0.7, showing suggestive statistical evidence. The target genes of these miRNAs were enriched for PI3K-Akt, Hippo, WNT, MAPK, and focal adhesion pathways.

CONCLUSIONS

Two differentially expressed miRNAs were associated with airflow levels in children with asthma and airflow obstruction in adults with COPD. This suggests that shared genetic regulatory systems may influence childhood airflow and contribute to adulthood airflow obstruction.

The Role of Inflammation in the Pathogenesis of Viral Respiratory Infections

Viral respiratory infections (VRIs) are a leading cause of morbidity and mortality worldwide, making them a significant public health concern. During infection, respiratory viruses, including Influenza virus, SARS-CoV-2, and respiratory syncytial virus (RSV), trigger an antiviral immune response, specifically boosting the inflammatory response that plays a critical role in their pathogenesis. The inflammatory response induced by respiratory viruses can be a double-edged sword since it can be initially induced to be antiviral and protective/reparative from virus-induced injuries. Still, it can also be detrimental to host cells and tissues. However, the mechanisms that differentiate the complex crosstalk between favorable host inflammatory responses and harmful inflammatory responses are poorly understood. This review explores the complex interplay between viral pathogens and the host immune response, mainly focusing on the role of inflammation in the pathogenesis of VRIs. We discuss how inflammation can both contain and exacerbate the progression of viral infections, highlighting potential therapeutic targets and emerging drugs for modulating the aberrant inflammatory responses during VRIs.

Emerging Anti-Inflammatory COPD Treatments: Potential Cardiovascular Impacts

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition often complicated by cardiovascular disease (CVD) due to shared inflammatory pathways. This review explores the cardiovascular impacts of emerging anti-inflammatory therapies in COPD. Phosphodiesterase (PDE) inhibitors may offer anti-inflammatory effects with improved lung function but pose potential risks for arrhythmias when PDE3 is inhibited although PDE4 inhibitors reduce cardiovascular events by improving endothelial function and reducing thrombosis. Similarly, p38 mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) inhibitors target COPD-related inflammation and may benefit COPD patients with CVD. p38 MAPK inhibitors reduce cardiac fibrosis, enhance contractility and lower the risk of arrhythmia. PI3K inhibitors target the PI3K/Akt pathway, which drives atherosclerosis and cardiac fibrosis, and thus potentially mitigate both plaque instability and fibrosis. Biologic therapies, including monoclonal antibodies that inhibit IL-5, IL-13/IL-4, thymic stromal lymphopoietin, IL-33, and IL-17A, show promise in reducing exacerbations but require close cardiovascular monitoring due to their immunomodulatory effects. Single-target inhibitors of neutrophil elastase or matrix metalloproteinases show limited efficacy in COPD but may aid cardiovascular patients by stabilizing atherosclerotic plaques through promoting vascular smooth muscle cell proliferation. However, their tendency to degrade the extracellular matrix and attract immune cells may heighten plaque rupture risk, contraindicating use in CVD. Alpha-1 antitrypsin replacement therapy holds promise, potentially reducing COPD exacerbations and providing cardiovascular protection, especially in myocardial injury. Understanding the influence of these innovative therapies on CVD is vital, making it imperative to examine these molecules in COPD patients with CVD at an early stage.

Aromadendrin Ameliorates Airway Inflammation in Experimental Mice with Chronic Obstructive Pulmonary Disease

Aromadendrin (ARO) is an active plant compound that exerts anti-inflammatory effects. However, its ameliorative effects on chronic obstructive pulmonary disease (COPD) remain unclear. Therefore, we investigated the inhibitory effects of ARO on bronchial inflammation using an experimental model of COPD. In vivo analysis confirmed a notable increase in the number of neutrophils/macrophages and the formation of reactive oxygen species (ROS), myeloperoxidase (MPO), interleukin (IL)-6/IL-1β, and monocyte chemoattractant protein (MCP)-1 in the bronchoalveolar lavage (BAL) fluid of COPD mice, which was attenuated by oral gavage of ARO. In addition, hematoxylin and eosin staining showed a notable cell influx in the lungs of the COPD group, which was ameliorated by ARO. Western blotting revealed that ARO decreased the upregulation of neutrophil elastase expression in the lungs of the COPD group. Furthermore, periodic acid-Schiff staining showed that increased mucus formation in the lungs of the COPD group was downregulated by ARO. ARO also blocked CREB activation in the lungs of COPD mice. This in vivo, anti-inflammatory effect of ARO was accompanied by its modulatory effect on the activation of the MAPK/NF-κB/NLRP3 inflammasome. In summary, our study demonstrated that ARO has protective effects on bronchial inflammation by attenuating immune cell accumulation, toxic molecule/cytokine/chemokine formation, and MAPK/NF-κB/NLRP3 inflammasome activation, suggesting the potential development of ARO as an adjuvant for the prevention and treatment of COPD.

Role for IRAK-4 and p38 in Neutrophil Signaling in Response to Bacterial Lipoproteins from Staphylococcus aureus

Neutrophils, polymorphonuclear leukocytes (PMN), express numerous pattern recognition receptors, including TLRs, capable of recognizing a wide variety of pathogens. Receptor engagement initiates a cascade of PMN responses with some occurring in seconds, and some requiring de novo protein synthesis over the course of many hours. Although numerous species of bacteria and bacterial products have been shown to activate PMN via TLRs, the signaling intermediates required for distinct PMN responses have not been well-defined in human PMN. Given the potential for host tissue damage by overexuberant PMN activity, a better understanding of neutrophil signaling is needed to generate effective therapies. We hypothesized that PMN responses to a lipoprotein-containing cell membrane preparation from methicillin-resistant S. aureus (MRSA-CMP) would activate signaling via IRAK4 and p38, with potentially distinct pathways for early vs. late responses. Using human PMN we investigated MRSA-CMP-elicited reactive oxygen species (ROS) production, elastase activity, NET formation, IL-8 production, and the role of IRAK4 and p38 activation. MRSA-CMP elicited ROS in a concentration and lipoprotein-dependent manner. MRSA-CMP elicited phosphorylation of p38 MAPK, and MRSA-CMP-elicited ROS production was partially dependent on p38 MAPK and IRAK4 activation. Inhibition of IRAK4 resulted in a reduction of p38 phosphorylation. MRSA-CMP-elicited elastase activity and NET formation was partially dependent on p38 MAPK activation, but independent of IRAK4 activation. MRSA-CMP-elicited IL-8 production required both p38 and IRAK4 activation. In conclusion, MRSA-CMP elicits PMN responses via distinct signaling pathways. There is potential to target components of the neutrophil inflammatory response without compromising critical pathogen-specific immune functions.

Tobacco introduced Perilla frutescens and Ocimum basilicum genes attenuates neutrophilic inflammation in lung tissues of COPD rats

The new-type tobacco varieties "Zisu" and "Luole" were obtained by distant hybridization between N. tabacum L. var. HHY and Perilla frutescens and Ocimum basilicum, with obviously different chemical composition. Smoking is the major risk factor for COPD, characterized by neutrophil-dominant inflammation. In the present study, rat COPD model was established by cigarette exposure, and the health hazard of three varieties was compared by general condition observation, pathological and morphological evaluation, total and differential cell numeration, and characterization of major inflammatory mediators and MAPK/NF-κB pathway, etc. Rats in "HHY" group developed obvious symptoms such as cough, dyspnea, mental fatigue, etc., but these symptoms were obviously mitigated in "Zisu" and "Luole" groups. H&E staining analysis, including score, MLI, MAN, wt% and WA%, showed that "Zisu" and "Luole" significantly alleviated lung injury and the degree of airway remodeling and emphysema compared to "HHY". In BALF, the number of total leukocyte and the percent neutrophils in "Zisu" and "Luole" groups were evidently lower than "HHY" group. The levels of inflammatory mediators, such as IL-8, MPO, MIP-2, LTB4, TNF-α and neutrophil elastase, in "HHY" group were obviously higher than "Zisu" and "Luole" groups. The ROS-mediated NF-κB p65 and p38MAPK pathways may play an important role. Results indicated that tobacco introduced perilla and basil genes could remarkably attenuate recruitment, infiltration and activation of neutrophils and intervene in airway inflammation, retarding disease progression, especially "Zisu". Changes in chemical composition via breeding techniques may be a novel way for tobacco harm reduction.

Reactive oxygen species (ROS) scavenging biomaterials for anti-inflammatory diseases: from mechanism to therapy

Inflammation is a fundamental defensive response to harmful stimuli, but the overactivation of inflammatory responses is associated with most human diseases. Reactive oxygen species (ROS) are a class of chemicals that are generated after the incomplete reduction of molecular oxygen. At moderate levels, ROS function as critical signaling molecules in the modulation of various physiological functions, including inflammatory responses. However, at excessive levels, ROS exert toxic effects and directly oxidize biological macromolecules, such as proteins, nucleic acids and lipids, further exacerbating the development of inflammatory responses and causing various inflammatory diseases. Therefore, designing and manufacturing biomaterials that scavenge ROS has emerged an important approach for restoring ROS homeostasis, limiting inflammatory responses and protecting the host against damage. This review systematically outlines the dynamic balance of ROS production and clearance under physiological conditions. We focus on the mechanisms by which ROS regulate cell signaling proteins and how these cell signaling proteins further affect inflammation. Furthermore, we discuss the use of potential and currently available-biomaterials that scavenge ROS, including agents that were engineered to reduce ROS levels by blocking ROS generation, directly chemically reacting with ROS, or catalytically accelerating ROS clearance, in the treatment of inflammatory diseases. Finally, we evaluate the challenges and prospects for the controlled production and material design of ROS scavenging biomaterials.

Nanoparticle-Exposure-Triggered Virus Reactivation Induces Lung Emphysema in Mice

Nanoparticles (NPs) released from engineered materials or combustion processes as well as persistent herpesvirus infection are omnipresent and are associated with chronic lung diseases. Previously, we showed that pulmonary exposure of a single dose of soot-like carbonaceous NPs (CNPs) or fiber-shaped double-walled carbon nanotubes (DWCNTs) induced an increase of lytic virus protein expression in mouse lungs latently infected with murine γ-herpesvirus 68 (MHV-68), with a similar pattern to acute infection suggesting virus reactivation. Here we investigate the effects of a more relevant repeated NP exposure on lung disease development as well as herpesvirus reactivation mechanistically and suggest an avenue for therapeutic prevention. In the MHV-68 mouse model, progressive lung inflammation and emphysema-like injury were detected 1 week after repetitive CNP and DWCNT exposure. NPs reactivated the latent herpesvirus mainly in CD11b+ macrophages in the lungs. In vitro, in persistently MHV-68 infected bone marrow-derived macrophages, ERK1/2, JNK, and p38 MAPK were rapidly activated after CNP and DWCNT exposure, followed by viral gene expression and increased viral titer but without generating a pro-inflammatory signature. Pharmacological inhibition of p38 activation abrogated CNP- but not DWCNT-triggered virus reactivation in vitro, and inhibitor pretreatment of latently infected mice attenuated CNP-exposure-induced pulmonary MHV-68 reactivation. Our findings suggest a crucial contribution of particle-exposure-triggered herpesvirus reactivation for nanomaterial exposure or air pollution related lung emphysema development, and pharmacological p38 inhibition might serve as a protective target to alleviate air pollution related chronic lung disease exacerbations. Because of the required precondition of latent infection described here, the use of single hit models might have severe limitations when assessing the respiratory toxicity of nanoparticle exposure.

p38 MAPK signaling in chronic obstructive pulmonary disease pathogenesis and inhibitor therapeutics

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar remodeling. Although the abnormalities are primarily prompted by chronic exposure to inhaled irritants, maladjusted and self-reinforcing immune responses are significant contributors to the development and progression of the disease. The p38 isoforms are regarded as pivotal hub proteins that regulate immune and inflammatory responses in both healthy and disease states. As a result, their inhibition has been the subject of numerous recent studies exploring their therapeutic potential in COPD.

MAIN BODY

We performed a systematic search based on the PRISMA guidelines to find relevant studies about P38 signaling in COPD patients. We searched the PubMed and Google Scholar databases and used "P38" AND "COPD" Mesh Terms. We applied the following inclusion criteria: (1) human, animal, ex vivo and in vitro studies; (2) original research articles; (3) published in English; and (4) focused on P38 signaling in COPD pathogenesis, progression, or treatment. We screened the titles and abstracts of the retrieved studies and assessed the full texts of the eligible studies for quality and relevance. We extracted the following data from each study: authors, year, country, sample size, study design, cell type, intervention, outcome, and main findings. We classified the studies according to the role of different cells and treatments in P38 signaling in COPD.

CONCLUSION

While targeting p38 MAPK has demonstrated some therapeutic potential in COPD, its efficacy is limited. Nevertheless, combining p38 MAPK inhibitors with other anti-inflammatory steroids appears to be a promising treatment choice. Clinical trials testing various p38 MAPK inhibitors have produced mixed results, with some showing improvement in lung function and reduction in exacerbations in COPD patients. Despite these mixed results, research on p38 MAPK inhibitors is still a major area of study to develop new and more effective therapies for COPD. As our understanding of COPD evolves, we may gain a better understanding of how to utilize p38 MAPK inhibitors to treat this disease. Video Abstract.

The utility of long non-coding RNAs in chronic obstructive pulmonary disease: a comprehensive analysis

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) is one of the main causes of morbidity and mortality in the world. However, there are some patients who are not diagnosed early and correctly through routine methods because of inconspicuous or serious symptoms. This study aims to assess the diagnostic role of long non-coding RNA (lncRNA) in COPD.

METHODS

We searched literature from electronic databases, after excluding non-COPD literature, the bibliometric analysis was performed, and VOSviewer software was used to represent the data analyzed. Literature evaluating the diagnostic test accuracy of lncRNA for COPD was eligible, and the QUADAS-2 checklist was used to evaluate the quality. The pooled sensitivity (SEN), specificity (SPE), diagnostic odds ratio (DOR), and summary receiver operating characteristic curve (sROC) were used to analyze the overall diagnostic performance. Subgroup and meta-regression analyses were performed to explore the heterogeneity, and a funnel plot was assessed for publication bias. Also, lncRNAs related to COPD were identified and explored for their potential biological function.

RESULTS

An increased annual growth rate of literature on this subject from 2016 focused on COPD, humans, RNA, and lncRNA. The meta-analysis enrolled 17 literature indicated that the SEN, SPE, and DOR differentiating COPD patients from normal controls (NCs) were 0.86 (95% CI [0.80, 0.90]), 0.78 (95% CI [0.67, 0.86]), and 21.59 (95% CI [11.39, 40.91]), respectively. Meanwhile, lncRNAs had the ability to distinguish acute exacerbations of COPD (AECOPD) patients from COPD; the SEN, SPE, and DOR were 0.75 (95% CI [0.62, 0.85]), 0.81 (95% CI [0.71, 0.89]), and 13.02 (95% CI [7.76, 21.85]), respectively. The area under the sROC were calculated to be greater than 0.8 at least. Subgroup and meta-regression analysis showed that the types of specimens and dysregulated lncRNAs might affect the diagnostic accuracy. The funnel plot showed there was a certain publication bias. 41 lncRNAs related to COPD were identified and mainly located in the nucleus and cytoplasm, associated with proliferation, invasion, and prognosis. These lncRNA-binding proteins were involved in the spliceosome, Rap1 signaling pathway, MAPK signaling pathway, and so on.

CONCLUSION

LncRNA suggests potential diagnostic biomarkers and therapeutic targets for COPD patients.

Novel Anti-Inflammatory Approaches to COPD

Airway inflammation, driven by different types of inflammatory cells and mediators, plays a fundamental role in COPD and its progression. Neutrophils, eosinophils, macrophages, and CD4+ and CD8+ T lymphocytes are key players in this process, although the extent of their participation varies according to the patient's endotype. Anti-inflammatory medications may modify the natural history and progression of COPD. However, since airway inflammation in COPD is relatively resistant to corticosteroid therapy, innovative pharmacological anti-inflammatory approaches are required. The heterogeneity of inflammatory cells and mediators in annethe different COPD endo-phenotypes requires the development of specific pharmacologic agents. Indeed, over the past two decades, several mechanisms that influence the influx and/or activity of inflammatory cells in the airways and lung parenchyma have been identified. Several of these molecules have been tested in vitro models and in vivo in laboratory animals, but only a few have been studied in humans. Although early studies have not been encouraging, useful information emerged suggesting that some of these agents may need to be further tested in specific subgroups of patients, hopefully leading to a more personalized approach to treating COPD.

Progress in the development of kinase inhibitors for treating asthma and COPD

Current therapies to mitigate inflammatory responses involved in airway remodeling and associated pathological features of asthma and chronic obstructive pulmonary disease (COPD) are limited and largely ineffective. Inflammation and the release of cytokines and growth factors activate kinase signaling pathways that mediate changes in airway mesenchymal cells such as airway smooth muscle cells and lung fibroblasts. Proliferative and secretory changes in mesenchymal cells exacerbate the inflammatory response and promote airway remodeling, which is often characterized by increased airway smooth muscle mass, airway hyperreactivity, increased mucus secretion, and lung fibrosis. Thus, inhibition of relevant kinases has been viewed as a potential therapeutic approach to mitigate the debilitating and, thus far, irreversible airway remodeling that occurs in asthma and COPD. Despite FDA approval of several kinase inhibitors for the treatment of proliferative disorders, such as cancer and inflammation associated with rheumatoid arthritis and ulcerative colitis, none of these drugs have been approved to treat asthma or COPD. This review will provide a brief overview of the role kinases play in the pathology of asthma and COPD and an update on the status of kinase inhibitors currently in clinical trials for the treatment of obstructive pulmonary disease. In addition, potential issues associated with the current kinase inhibitors, which have limited their success as therapeutic agents in treating asthma or COPD, and alternative approaches to target kinase functions will be discussed.

Cigarette smoke extract combined with LPS reduces ABCA3 expression in chronic pulmonary inflammation may be related to PPARγ/ P38 MAPK signaling pathway

ABCA3 (ATP-binding cassette class A3) is a transmembrane transporter that plays a positive role in chronic pulmonary inflammation by regulating lipid metabolism. However, it is not completely clear whether ABCA3 and its signaling factors are involved in chronic pulmonary inflammation induced by the combination of CSE (cigarette smoke extract) and LPS (lipopolysaccharide). In this study, we used the method of combining CSE and LPS which was widely used to study lung inflammation-related diseases and has been proven effective in our group's studies to create in vivo and in vitro pulmonary inflammation models. The result showed that, after CSE in combination with LPS treatment, ABCA3 expression was downregulated in rat lung in vivo and in a human alveolar cell line in vitro. ABCA3 expression was upregulated, and related inflammatory factors were downregulated in the state of overexpression of PPARγ or inhibition of the p38 MAPK pathway, while PPARγ deletion or MAPK14 overexpression showed the opposite results. The level of PPARγ remained unchanged, and the expression of ABCA3 was upregulated in the state of the p38 MAPK pathway was inhibited under overexpression of PPARγ. These results indicate that CSE combined with LPS can result in downregulation of ABCA3 under conditions of inflammation, and that the p38 MAPK signaling pathway mediated by PPARγ can regulate the expression changes of ABCA3, thus providing new targets for treating chronic pulmonary inflammation.

Safety and efficacy of p38 mitogen-activated protein kinase inhibitors (MAPKIs) in COPD

Introduction: Chronic inflammation is the core mechanism of the development of chronic obstructive pulmonary disease (COPD). Corticosteroid resistance in COPD limits its anti-inflammatory potency. p38 MAPKIs were suggested as an alternative to corticosteroids despite the fact that there is currently no systematic review evaluating existing evidence.

Methods: This randomized controlled trials (RCT)-based systematic review with meta-analysis was conducted following the PRISMA statement. RCTs were searched and screened from 8 databases. Three types of data, including basic information of included studies, pre-defined outcome data, and quality assessment information were extracted. Pooling values and associated 95 % confidence intervals were deemed as statistically significant only when two-tailed p values were smaller than 0.05.

Results: This study included 10 RCTs with a total population of 1,751 [age, mean (SD) = 64.39 (8.06)]. Safety and several efficacy indicators of lung function, inflammatory biomarkers, and quality of life were meta-analyzed. Despite the improvement of post-bronchodilator-forced vital capacity (FVC), no difference between p38 MAPKIs and placebo was found in both safety and efficacy.

Conclusion: Compared with placebo, p38 MAPKIs are safe but did not show any significant effects in the COPD population. Results of this study should be regarded with caution due to the small number of included studies and heterogeneity from combining different p38 MAPKIs as a whole.

Systematic Review registration: PROSPERO #CRD42022302890.

Angiotensin II type-2 receptor activation in alveolar macrophages mediates protection against cigarette smoke-induced chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. Cumulative evidence has implicated renin-angiotensin system (RAS) in the pathogenesis of COPD. Alveolar macrophages (AMs) are the first line immune defense in the respiratory system and play a critical role in the lung homeostasis. This study aimed to investigate the role of AMs in contributing to the protective effects of angiotensin II type-2 receptor (AT2R) activation in cigarette smoke (CS)-induced COPD. The AM polarization, phagocytosis and metabolism, and the underlying biochemical mechanisms of compound 21 (C21), a selective and potent non-peptide small molecule AT2R agonist, were evaluated in a two-week CS-induced COPD mouse model. C21 restored AM phagocytosis ability, reversing CS-induced AM phagocytosis impairment. CS exposure polarized AMs towards M1 phenotype, whereas, C21 skewed the CS-exposed AMs towards M2 phenotype. C21 reprogrammed CS-exposed AM metabolism from a high glycolysis-driven process to support inflammation energy demand to a high mitochondrial respiration process to limit inflammation. Besides, C21 upregulated AT2R and Mas receptor levels in CS-exposed AMs, favoring the anti-inflammatory Ang II/AT2R axis and Ang 1-7/Mas axis in the RAS. C21 restored the normal levels of sirtuin 1 (SIRT1) and MAPK phosphatase 1 (MKP1) in CS-exposed AMs, leading to the reduction of phospho-p38, phospho-ERK and p65 subunit of NF-κB levels in CS-exposed AMs. We report here for the first time that AT2R agonist C21 acts by boosting the protective functions of AMs against CS-induced COPD, and our results support the development of AT2R agonist for the treatment of COPD.

Pathological Mechanism and Targeted Drugs of COPD

Chronic obstructive pulmonary disease (COPD) includes chronic bronchitis, emphysema, and small airway obstruction. Incompletely reversible airflow limitation, inflammation, excessive mucus secretion and bronchial mucosal epithelial lesions are the main pathological basis of the disease. The prevalence of COPD is increasingly worldwide, which has caused the burden on individuals and society. This paper summarizes the pathogenesis of COPD and clarifies the effect and mechanism of the latest targeted drugs for COPD. Besides, we focus on NOD-like receptor thermal protein domain associated protein 3 inflammasome (NLRP3 inflammasome). NLRP3 can promote production of interleukin-1β (IL-1β) and interleukin-18 (IL-18). NLRP3 is an important factor in the migratory aggregation of macrophages and neutrophils and the generation of oxidative stress. Inhibition of NLRP3 inflammasome indirectly blocks the inflammatory effects of IL-1β and IL-18, which may be regarded as an ideal target for COPD treatment.

Blood miRNAs Are Linked to Frequent Asthma Exacerbations in Childhood Asthma and Adult COPD

MicroRNAs have been independently associated with asthma and COPD; however, it is unclear if microRNA associations will overlap when evaluating retrospective acute exacerbations. Objective: We hypothesized that peripheral blood microRNAs would be associated with retrospective acute asthma exacerbations in a pediatric asthma cohort and that such associations may also be relevant to acute COPD exacerbations. Methods: We conducted small-RNA sequencing on 374 whole-blood samples from children with asthma ages 6-14 years who participated in the Genetics of Asthma in Costa Rica Study (GACRS) and 450 current and former adult smokers with and without COPD who participated in the COPDGene study. Measurements and Main Results: After QC, we had 351 samples and 649 microRNAs for Differential Expression (DE) analysis between the frequent (n = 183) and no or infrequent exacerbation (n = 168) groups in GACRS. Fifteen upregulated miRs had odds ratios (OR) between 1.22 and 1.59 for a doubling of miR counts, while five downregulated miRs had ORs between 0.57 and 0.8. These were assessed for generalization in COPDGene, where three of the upregulated miRs (miR-532-3p, miR-296-5p, and miR-766-3p) and two of the downregulated miRs (miR-7-5p and miR-451b) replicated. Pathway enrichment analysis showed MAPK and PI3K-Akt signaling pathways were strongly enriched for target genes of DE miRNAs and miRNAs generalizing to COPD exacerbations, as well as infection response pathways to various pathogens. Conclusion: miRs (451b; 7-5p; 532-3p; 296-5p and 766-3p) associated with both childhood asthma and adult COPD exacerbations may play a vital role in airflow obstruction and exacerbations and point to shared genomic regulatory machinery underlying exacerbations in both diseases.

The future of inhalation therapy in chronic obstructive pulmonary disease

The inhaled route is critical for the administration of drugs to treat patients suffering from COPD, but there is still an unmet need for new and innovative inhalers to address some limitations of existing products that do not make them suitable for many COPD patients. The treatment of COPD, currently limited to the use of bronchodilators, corticosteroids, and antibiotics, requires a significant expansion of the therapeutic armamentarium that is closely linked to the widening of knowledge on the pathogenesis and evolution of COPD. The great interest in the development of new drugs that may be able to interfere in the natural history of the disease is leading to the synthesis of numerous new molecules, of which however only a few have entered the stages of clinical development. On the other hand, further improvement of inhaled drug delivery could be an interesting possibility because it targets the organ of interest directly, requires significantly less drug to exert the pharmacological effect and, by lowering the amount of drug needed, reduces the cost of therapy. Unfortunately, however, the development of new inhaled drugs for use in COPD is currently too slow.

Therapeutic potential and mechanism of Dendrobium officinale polysaccharides on cigarette smoke-induced airway inflammation in rat

Chronic obstructive pulmonary disease (COPD) is among the leading causes of death worldwide, and is characterized by persistent respiratory symptoms and airflow limitation due to chronic airway inflammation. Cigarette smoking is a major risk factor for COPD. This study aims to determine the therapeutic effects of polysaccharides extracted from Dendrobium officinale (DOPs), a valuable traditional Chinese Medicinal herb, on cigarette smoke (CS)-induced airway inflammation in a rat passive smoking model. Male Sprague-Dawley rats were exposed to CS or sham air (SA) as control for a 56-day period. On Day 29, rats were subdivided and given water, DOPs or N-acetylcysteine (NAC) via oral gavage on a daily basis for the remaining duration. DOPs reduced CS-induced oxidative stress as evidenced by reducing malondialdehyde (MDA) levels in the lung. DOPs also exerted potent anti-inflammatory properties as evidenced by a reduction in the number of lymphocytes and monocytes in serum, significantly attenuating infiltration of inflammatory cells in lung tissue, as well as pro-inflammatory mediators in serum, bronchoalveolar lavage (BAL) and lung. Additionally, DOPs inhibited the CS-induced activation of ERK, p38 MAPK and NF-κB signaling pathways. These findings suggest that DOPs may have potentially beneficial effects in limiting smoking-related lung oxidative stress, and inflammation mediated via the inhibition of MAPK and NF-κB signaling pathways in smokers, without or with COPD.

Glucocorticoid Resistance: Interference between the Glucocorticoid Receptor and the MAPK Signalling Pathways

Endogenous glucocorticoids (GCs) are steroid hormones that signal in virtually all cell types to modulate tissue homeostasis throughout life. Also, synthetic GC derivatives (pharmacological GCs) constitute the first-line treatment in many chronic inflammatory conditions with unquestionable therapeutic benefits despite the associated adverse effects. GC actions are principally mediated through the GC receptor (GR), a ligand-dependent transcription factor. Despite the ubiquitous expression of GR, imbalances in GC signalling affect tissues differently, and with variable degrees of severity through mechanisms that are not completely deciphered. Congenital or acquired GC hypersensitivity or resistance syndromes can impact responsiveness to endogenous or pharmacological GCs, causing disease or inadequate therapeutic outcomes, respectively. Acquired GC resistance is defined as loss of efficacy or desensitization over time, and arises as a consequence of chronic inflammation, affecting around 30% of GC-treated patients. It represents an important limitation in the management of chronic inflammatory diseases and cancer, and can be due to impairment of multiple mechanisms along the GC signalling pathway. Among them, activation of the mitogen-activated protein kinases (MAPKs) and/or alterations in expression of their regulators, the dual-specific phosphatases (DUSPs), have been identified as common mechanisms of GC resistance. While many of the anti-inflammatory actions of GCs rely on GR-mediated inhibition of MAPKs and/or induction of DUSPs, the GC anti-inflammatory capacity is decreased or lost in conditions of excessive MAPK activation, contributing to disease susceptibility in tissue- and disease- specific manners. Here, we discuss potential strategies to modulate GC responsiveness, with the dual goal of overcoming GC resistance and minimizing the onset and severity of unwanted adverse effects while maintaining therapeutic potential.

MiR-29b-3p aggravates NG108-15 cell apoptosis triggered by fluorine combined with aluminum

The mechanism of learning and memory impairment induced by the combination of fluorine and aluminum (FA) is not fully understood. The results of our previous research demonstrated that miR-29b-3p is a differentially expressed miRNA in the hippocampi of rat offspring exposed to FA; this miRNA is related to learning and memory and apoptosis. Based on these findings, in vitro studies were designed to assess the role of miR-29b-3p in neuronal apoptosis caused by the coexistence of FA. In the present study, the viability of mouse neuroblastoma-rat glioma hybrid cell (NG108-15 cell) was analyzed using Cell Counting Kit-8 (CCK-8). Apoptosis was detected by a Novocyte Flow Cytometer. Relative mRNA and protein expression levels were evaluated by real-time fluorescence quantitative PCR (qRT-PCR) and Western blotting (WB), respectively. The results showed that FA aggravated NG108-15 cell apoptosis by inhibiting dual-specificity phosphatase-2 (Dusp2) via increased miR-29b-3p. Accordingly, a dual-luciferase reporter assay showed that miR-29b-3p modulated Dusp2 protein levels by targeting its 3'-untranslated region. These findings show, for the first time, that miR-29b-3p is involved in neuronal apoptosis triggered by FA by targeting Dusp2.

Predictors of Renal Function Worsening in Patients with Chronic Obstructive Pulmonary Disease (COPD): A Multicenter Observational Study

Background. Chronic obstructive pulmonary disease (COPD) patients have multiple comorbidities which may affect renal function. Chronic kidney disease (CKD) is a risk factor for adverse outcomes in COPD patients. The predictors of CKD in COPD are not well investigated. Methods. A multicenter observational cohort study including patients affected by COPD (GOLD stages 1 and 2) was carried out. Principal endpoints were the incidence of CKD, as defined by an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², and the rapid decline of eGFR >5 mL/min/1.73 m²/year. Results. We enrolled 707 outpatients. Overall, 157 (22.2%) patients had CKD at baseline. Patients with CKD were older, with higher serum uric acid (UA) levels, and lower FEV₁. During a mean follow-up of 52.3 ± 30.2 months, 100 patients developed CKD, and 200 patients showed a rapid reduction of eGFR. Multivariable Cox regression analysis displayed that UA (hazard ratio (HR) 1.148, p < 0.0001) and diabetes (HR 1.050, p < 0.0001) were predictors of incident CKD. The independent predictors of rapidly declining renal function were represented by an increase of 1 mg/dL in UA (odds ratio (OR) 2.158, p < 0.0001)), an increase of 10 mL/min/1.73 m² in baseline eGFR (OR 1.054, p < 0.0001) and the presence of diabetes (OR 1.100, p < 0.009). Conclusions. This study shows that COPD patients have a significant worsening of renal function over time and that UA and diabetes were the two strongest predictors. Optimal management of these risk factors may reduce the incidence of CKD in this population thus probably improving clinical outcome.

Expression of a constitutively active p38α mutant in mice causes early death, anemia, and accumulation of immunosuppressive cells

The MAP kinase p38α is associated with numerous processes in eukaryotes, and its elevated activity is a prominent feature of inflammatory diseases, allergies, and aging. Since p38α is a nodal component of a complex signaling network, it is difficult to reveal exactly how p38α contributes to disparate outcomes. Identification of p38α -specific effects requires activation of p38α per se in vivo. We generated a transgenic mouse model that meets this requirement by allowing inducible and reversible expression of an intrinsically active p38α molecule (p38αD176A+F327S ). p38α's activation across all murine tissues resulted in a significant loss of body weight and death of about 40% of the mice within 17 weeks of activation, although most tissues were unaffected. Flow cytometric analysis of the lungs and bronchoalveolar lavage fluid detected an accumulation of 'debris' within the airways, suggesting impaired clearance. It also revealed increased numbers of alternatively activated alveolar macrophages and myeloid-derived suppressor cells within the lung, pointing at suppression and resolution of inflammation. Blood count suggested that mice expressing p38αD176A+F327S suffer from hemolytic anemia. Flow cytometry of bone marrow revealed a reduced number of hematopoietic stem cells and abnormalities in the erythroid lineage. Unexpectedly, p38α's substrate MAPKAPK2, mitogen-activated protein kinase-activated protein kinase 2 was downregulated in mice expressing p38αD176A+F327S , suggesting that constitutive activity of p38α may impose pathological phenotypes by downregulating downstream components, perhaps via a feedback inhibition mechanism. In summary, this new mouse model shows that induced p38α activity per se is hazardous to mouse vitality and welfare, although pathological parameters are apparent only in blood count, bone marrow, and lungs.

Classes of drugs that target the cellular components of inflammation under clinical development for COPD

INTRODUCTION

The persistent inflammation that characterizes COPD and affects its natural course also impacting on symptoms has prompted research to find molecules that can regulate the inflammatory process but still available anti-inflammatory therapies provide little or no benefit in COPD patients. Consequently, numerous anti-inflammatory molecules that are effective in animal models of COPD have been or are being evaluated in humans.

AREAS COVERED

In this article we describe several classes of drugs that target the cellular components of inflammation under clinical development for COPD.

EXPERT OPINION

Although the results of many clinical trials with new molecules have often been disappointing, several studies are underway to investigate whether some of these molecules may be effective in treating specific subgroups of COPD patients. Indeed, the current perspective is to apply a more personalized treatment to the patient. This means being able to better define the patient's inflammatory state and treat it in a targeted manner. Unfortunately, the difficulty in translating encouraging experimental data into human clinical trials, the redundancy in the effects induced by signal-transmitting substances and the nonspecific effects of many classes that are undergoing clinical trials, do not yet allow specific inflammatory cell types to be targeted.

Atypical p38 Signaling, Activation, and Implications for Disease

The mitogen-activated protein kinase (MAPK) p38 is an essential family of kinases, regulating responses to environmental stress and inflammation. There is an ever-increasing plethora of physiological and pathophysiological conditions attributed to p38 activity, ranging from cell division and embryonic development to the control of a multitude of diseases including retinal, cardiovascular, and neurodegenerative diseases, diabetes, and cancer. Despite the decades of intense investigation, a viable therapeutic approach to disrupt p38 signaling remains elusive. A growing body of evidence supports the pathological significance of an understudied atypical p38 signaling pathway. Atypical p38 signaling is driven by a direct interaction between the adaptor protein TAB1 and p38α, driving p38 autophosphorylation independent from the classical MKK3 and MKK6 pathways. Unlike the classical MKK3/6 signaling pathway, atypical signaling is selective for just p38α, and at present has only been characterized during pathophysiological stimulation. Recent studies have linked atypical signaling to dermal and vascular inflammation, myocardial ischemia, cancer metastasis, diabetes, complications during pregnancy, and bacterial and viral infections. Additional studies are required to fully understand how, when, where, and why atypical p38 signaling is induced. Furthermore, the development of selective TAB1-p38 inhibitors represents an exciting new opportunity to selectively inhibit pathological p38 signaling in a wide array of diseases.

Role of p38 Mitogen-Activated Protein Kinase in Asthma and COPD: Pathogenic Aspects and Potential Targeted Therapies

Among the various members of the mitogen-activated protein kinase (MAPK) family, p38 MAPK subgroup is the most involved in airway and lung inflammation underlying asthma and chronic obstructive pulmonary disease (COPD). In particular, several environmental agents including aeroallergens, cigarette smoke, airborne pollutants, viral and bacterial pathogens activate the p38α isoform which in turn up-regulates the expression of multiple proinflammatory cytokines and chemokines, as well as the production of some fibrogenic factors. Therefore, p38 MAPK-induced bronchial inflammation and remodelling significantly contribute to the development, persistence and amplification of airflow limitation, which is the hallmark of asthma and COPD. Such advances in our understanding of p38 role in the pathobiology of the above widespread, chronic obstructive respiratory diseases, have led to consider p38 MAPK as a suitable molecular target for novel treatment strategies. Indeed, many studies have been carried out in both animal and clinical settings, with the aim of evaluating the potential therapeutic effects of p38 MAPK inhibitors in both asthma and COPD.

Oxidative Imbalance as a Crucial Factor in Inflammatory Lung Diseases: Could Antioxidant Treatment Constitute a New Therapeutic Strategy?

Inflammatory lung disease results in a high global burden of death and disability. There are no effective treatments for the most severe forms of many inflammatory lung diseases, such as chronic obstructive pulmonary disease, emphysema, corticosteroid-resistant asthma, and coronavirus disease 2019; hence, new treatment options are required. Here, we review the role of oxidative imbalance in the development of difficult-to-treat inflammatory lung diseases. The inflammation-induced overproduction of reactive oxygen species (ROS) means that endogenous antioxidants may not be sufficient to prevent oxidative damage, resulting in an oxidative imbalance in the lung. In turn, intracellular signaling events trigger the production of proinflammatory mediators that perpetuate and aggravate the inflammatory response and may lead to tissue damage. The production of high levels of ROS in inflammatory lung diseases can induce the phosphorylation of mitogen-activated protein kinases, the inactivation of phosphoinositide 3-kinase (PI3K) signaling and histone deacetylase 2, a decrease in glucocorticoid binding to its receptor, and thus resistance to glucocorticoid treatment. Hence, antioxidant treatment might be a therapeutic option for inflammatory lung diseases. Preclinical studies have shown that antioxidants (alone or combined with anti-inflammatory drugs) are effective in the treatment of inflammatory lung diseases, although the clinical evidence of efficacy is weaker. Despite the high level of evidence for the efficacy of antioxidants in the treatment of inflammatory lung diseases, the discovery and clinical investigation of safer, more efficacious compounds are now a priority.

Mesenchymal Stem Cell Derived Exosomes: a Nano Platform for Therapeutics and Drug Delivery in Combating COVID-19

The recent pandemic situation transpired due to coronavirus novel strain SARS-CoV-2 has become a global concern. This human coronavirus (HCov-19) has put the world on high alert as the numbers of confirmed cases are continuously increasing. The world is now fighting against this deadly virus and is leaving no stone unturned to find effective treatments through testing of various available drugs, including those effective against flu, malaria, etc. With an urgent need for the development of potential strategies, two recent studies from China using Mesenchymal Stem Cells (MSCs) to treat COVID-19 pneumonia have shed some light on a potential cure for the COVID-19 infected patients. However, MSCs, despite being used in various other clinical trials have always been questioned for their tendency to aggregate or form clumps in the injured or disease microenvironment. It has also been reported in various studies that exosomes secreted by these MSCs, contribute towards the cell's biological and therapeutic efficacy. There have been reports evaluating the safety and feasibility of these exosomes in various lung diseases, thereby proposing them as a cell-free therapeutic agent. Also, attractive features like cell targeting, low-immunogenicity, safety, and high biocompatibility distinguish these exosomes from other synthetic nano-vesicles and thus potentiate their role as a drug delivery nano-platform. Building upon these observations, herein, efforts are made to give an overview of stem cell-derived exosomes as an appealing therapeutic agent and drug delivery nano-carrier. In this review, we briefly recapitulate the recent evidence and developments in understanding exosomes as a promising candidate for novel nano-intervention in the current pandemic scenario. Furthermore, this review will highlight and discuss mechanistic role of exosomes to combat severe lung pathological conditions. We have also attempted to dwell into the nano-formulation of exosomes for its better applicability, storage, and stability thereby conferring them as off the shelf therapeutic.

Prospects for COPD treatment

The management of chronic obstructive pulmonary disease (COPD) is fundamentally still heavily dependent on the use of bronchodilators and corticosteroids. Therefore, there is a need for alternative, more effective and safer therapeutic approaches. In particular, since inflammation in COPD lungs is often poorly responsive to corticosteroid treatment, novel pharmacological anti-inflammatory approaches are needed to optimally treat COPD patients. There have been multiple attempts to develop drugs that inhibit recruitment and activation of inflammatory cells, such as macrophages, neutrophils and T-lymphocytes, in the lungs of patients with COPD or target inflammatory mediators that are important in the recruitment or activation of these inflammatory cells or released by such cells. This review article focuses on novel classes of anti-inflammatory drugs that have already been tested in humans as possible treatments for patients with COPD.

Why do some asthma patients respond poorly to glucocorticoid therapy?

Glucocorticosteroids are the first-line therapy for controlling airway inflammation in asthma. They bind intracellular glucocorticoid receptors to trigger increased expression of anti-inflammatory genes and suppression of pro-inflammatory gene activation in asthmatic airways.

In the majority of asthma patients, inhaled glucocorticoids are clinically efficacious, improving lung function and preventing exacerbations. However, 5–10 % of the asthmatic population respond poorly to high dose inhaled and then systemic glucocorticoids. These patients form a category of severe asthma associated with poor quality of life, increased morbidity and mortality, and constitutes a major societal and health care burden. Inadequate therapeutic responses to glucocorticoid treatment is also reported in other inflammatory conditions such as rheumatoid arthritis and inflammatory bowel disease; however, asthma represents the most studied steroid-refractory disease. Several cellular and molecular events underlying glucocorticoid resistance in asthma have been identified involving abnormalities of glucocorticoid receptor signaling pathways. These events have been strongly related to immunological dysregulation, genetic, and environmental factors such as cigarette smoking or respiratory infections. A better understanding of the multiple mechanisms associated with glucocorticoid insensitivity in asthma phenotypes could improve quality of life for people with asthma but would also provide transferrable knowledge for other inflammatory diseases. In this review, we provide an update on the molecular mechanisms behind steroid-refractory asthma. Additionally, we discuss some therapeutic options for treating those asthmatic patients who respond poorly to glucocorticoid therapy.