Crosstalk between mAChRM3 and β2AR, via acetylcholine PI3/PKC/PBEP1/Raf-1 MEK1/2/ERK1/2 pathway activation, in human bronchial epithelial cells after long-term cigarette smoke exposure

The Bronchodilator and Anti-Inflammatory Effect of Long-Acting Muscarinic Antagonists in Asthma: An EAACI Position Paper

As cholinergic innervation is a major contributor to increased vagal tone and mucus secretion, inhaled long-acting muscarinic antagonists (LAMA) are a pillar for the treatment of chronic obstructive pulmonary disease and asthma. By blocking the muscarinic receptors expressed in the lung, LAMA improve lung function and reduce exacerbations in asthma patients who remained poorly controlled despite treatment with inhaled corticosteroids and long-acting β2 agonists. Asthma guidelines recommend LAMA as a third controller to be added on before the initiation of biologicals. In addition to bronchodilation, LAMA also exert anti-inflammatory and anti-fibrotic effects by inhibiting muscarinic receptors present in neutrophils, macrophages, fibroblasts and airway smooth muscle cells. Thus, besides bronchodilation, LAMA might provide additional therapeutic effects, thereby supporting an endotype-driven approach to asthma management. The Position Paper, developed by the Asthma Section of the European Academy of Allergy and Clinical Immunology, discusses the main cholinergic pathways in the lung, reviews the findings of significant clinical trials and real-life studies on LAMA use in asthma, examines the placement of these drugs in asthma clinical guidelines, and considers the potential for personalised medicine with LAMA in both adult and paediatric asthma patients.

Coronavirus nucleocapsid protein enhances the binding of p-PKCα to RACK1: Implications for inhibition of nucleocytoplasmic trafficking and suppression of the innate immune response

The hallmark of coronavirus infection lies in its ability to evade host immune defenses, a process intricately linked to the nuclear entry of transcription factors crucial for initiating the expression of antiviral genes. Central to this evasion strategy is the manipulation of the nucleocytoplasmic trafficking system, which serves as an effective target for the virus to modulate the expression of immune response-related genes. In this investigation, we discovered that infection with the infectious bronchitis virus (IBV) dynamically impedes the nuclear translocation of several transcription factors such as IRF3, STAT1, STAT2, NF-κB p65, and the p38 MAPK, leading to compromised transcriptional induction of key antiviral genes such as IFNβ, IFITM3, and IL-8. Further examination revealed that during the infection process, components of the nuclear pore complex (NPC), particularly FG-Nups (such as NUP62, NUP153, NUP42, and TPR), undergo cytosolic dispersion from the nuclear envelope; NUP62 undergoes phosphorylation, and NUP42 exhibits a mobility shift in size. These observations suggest a disruption in nucleocytoplasmic trafficking. Screening efforts identified the IBV nucleocapsid (N) protein as the agent responsible for the cytoplasmic distribution of FG-Nups, subsequently hindering the nuclear entry of transcription factors and suppressing the expression of antiviral genes. Interactome analysis further revealed that the IBV N protein interacts with the scaffold protein RACK1, facilitating the recruitment of activated protein kinase C alpha (p-PKCα) to RACK1 and relocating the p-PKCα-RACK1 complex to the cytoplasm. These observations are conserved across diverse coronaviruses N proteins. Concurrently, the presence of both RACK1 and PKCα/β proved essential for the phosphorylation and cytoplasmic dispersion of NUP62, the suppression of antiviral cytokine expression, and efficient virus replication. These findings unveil a novel, highly effective, and evolutionarily conserved mechanism.

Smoking and vaping alter genes related to mechanisms of SARS-CoV-2 susceptibility and severity: a systematic review and meta-analysis

BACKGROUND

Evidence for the impact of smoking on coronavirus disease 2019 (COVID-19) is contradictory, and there is little research on vaping. Here we provide greater clarity on mechanisms perturbed by tobacco cigarette, electronic cigarette and nicotine exposures that may impact the risks of infection and/or disease severity.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the Ovid and Web of Science databases were searched. Study design and exposure-induced gene expression changes were extracted. Each study was quality assessed and higher confidence scores were assigned to genes consistently changed across multiple studies following the same exposure. These genes were used to explore pathways significantly altered following exposure.

RESULTS

125 studies provided data on 480 genes altered by exposure to tobacco cigarettes, e-cigarettes, nicotine or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Genes involved in both SARS-CoV-2 viral-entry and inflammation were changed following exposure. Pathway analysis revealed that many of those genes with high confidence scores are involved in common cellular processes relating to hyperinflammatory immune responses.

CONCLUSION

Exposure to tobacco cigarettes, e-cigarettes or nicotine may therefore impact initial host-pathogen interactions and disease severity. Smokers and vapers of e-cigarettes with nicotine could potentially be at increased risk of SARS-CoV-2 infection, associated cytokine storm, and acute respiratory distress syndrome. However, further research is required, particularly on e-cigarettes, to determine the biological mechanisms involved in perturbation of viral-entry genes and host-pathogen interactions and subsequent responses within the respiratory tract. This will improve our physiological understanding of the impact of smoking and vaping on COVID-19, informing public health advice and providing improved guidance for management of SARS-CoV-2 and other respiratory viruses.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges. Disruption of epithelial integrity is a key factor contributing to multiple processes underlying asthma pathology. In this review, we first discuss the unmet need in asthma management and provide an overview of the structure and function of the airway epithelium. We then focus on key pathophysiological changes that occur in the airway epithelium, including epithelial barrier disruption, immune hyperreactivity, remodelling, mucus hypersecretion and mucus plugging, highlighting how these processes manifest clinically and how they might be targeted by current and novel therapeutics.

Phenotype overlap in the natural history of asthma

The heterogeneity of asthma makes it challenging to unravel the pathophysiologic mechanisms of the disease. Despite the wealth of research identifying diverse phenotypes, many gaps still remain in our knowledge of the disease's complexity. A crucial aspect is the impact of airborne factors over a lifetime, which often results in a complex overlap of phenotypes associated with type 2 (T2), non-T2 and mixed inflammation. Evidence now shows overlaps between the phenotypes associated with T2, non-T2 and mixed T2/non-T2 inflammation. These interconnections could be induced by different determinants such as recurrent infections, environmental factors, T-helper plasticity and comorbidities, collectively resulting in a complex network of distinct pathways generally considered as mutually exclusive. In this scenario, we need to abandon the concept of asthma as a disease characterised by distinct traits grouped into static segregated categories. It is now evident that there are multiple interplays between the various physiologic, cellular and molecular features of asthma, and the overlap of phenotypes cannot be ignored.

Understanding Mechanisms of RKIP Regulation to Improve the Development of New Diagnostic Tools

Simple Summary

Raf Kinase Inhibitor protein is a protein that governs multiple intracellular signalling involved primarily in the progression of tumours and the development of metastases. In this review, we discussed the main mechanisms that regulate the expression and activity of RKIP with the aim of identifying the link between the transcriptional, post-transcriptional and post-translational events in different tumour settings. We also tried to analyse the studies that have measured the levels of RKIP in biological fluids in order to highlight the possible advantages and potential of RKIP assessment to obtain an accurate diagnosis and prognosis of various tumours.

Abstract

One of the most dangerous aspects of cancer cell biology is their ability to grow, spread and form metastases in the main vital organs. The identification of dysregulated markers that drive intracellular signalling involved in the malignant transformation of neoplastic cells and the understanding of the mechanisms that regulate these processes is undoubtedly a key objective for the development of new and more targeted therapies. RAF-kinase inhibitor protein (RKIP) is an endogenous tumour suppressor protein that affects tumour cell survival, proliferation, and metastasis. RKIP might serve as an early tumour biomarker since it exhibits significantly different expression levels in various cancer histologies and it is often lost during metastatic progression. In this review, we discuss the specific impact of transcriptional, post-transcriptional and post-translational regulation of expression and activation/inhibition of RKIP and focus on those tumours for which experimental data on all these factors are available. In this way, we could select how these processes cooperate with RKIP expression in (1) Lung cancer; (2) Colon cancer, (3) Breast cancer; (4) myeloid neoplasm and Multiple Myeloma, (5) Melanoma and (6) clear cell Renal Cell Carcinoma. Furthermore, since RKIP seems to be a key marker of the development of several tumours and it may be assessed easily in various biological fluids, here we discuss the potential role of RKIP dosing in more accessible biological matrices other than tissues. Moreover, this objective may intercept the still unmet need to identify new and more accurate markers for the early diagnosis and prognosis of many tumours.

Muscarinic receptor antagonists and airway inflammation: A systematic review on pharmacological models

Airway inflammation is crucial in the pathogenesis of many respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Current evidence supports the beneficial impact of muscarinic receptor antagonists against airway inflammation from bench-to-bedside. Considering the numerous sampling approaches and the ethical implications required to study inflammation in vivo in patients, the use of pre-clinical models is inevitable. Starting from our recently published systematic review concerning the impact of muscarinic antagonists, we have systematically assessed the current pharmacological models of airway inflammation and provided an overview on the advances in in vitro and ex vivo approaches. The purpose of in vitro models is to recapitulate selected pathophysiological parameters or processes that are crucial to the development of new drugs within a controlled environment. Nevertheless, immortalized cell lines or primary airway cells present major limitations, including the inability to fully replicate the conditions of the corresponding cell types within a whole organism.

Induced animal models are extensively used in research in the attempt to replicate a respiratory condition reflective of a human pathological state, although considering animal models with spontaneously occurring respiratory diseases may be more appropriate since most of the clinical features are accompanied by lung pathology resembling that of the human condition.

In recent years, three-dimensional organoids have become an alternative to animal experiments, also because animal models are unable to fully mimic the complexity of human pulmonary diseases. Ex vivo studies performed on human isolated airways have a superior translational value compared to in vitro and animal models, as they retain the morphology and the microenvironment of the lung in vivo.

In the foreseeable future, greater effort should be undertaken to rely on more physiologically relevant models, that provide translational value into clinic and have a direct impact on patient outcomes.

Cellular and Molecular Signatures of Oxidative Stress in Bronchial Epithelial Cell Models Injured by Cigarette Smoke Extract

Exposure of the airways epithelium to environmental insults, including cigarette smoke, results in increased oxidative stress due to unbalance between oxidants and antioxidants in favor of oxidants. Oxidative stress is a feature of inflammation and promotes the progression of chronic lung diseases, including Chronic Obstructive Pulmonary Disease (COPD). Increased oxidative stress leads to exhaustion of antioxidant defenses, alterations in autophagy/mitophagy and cell survival regulatory mechanisms, thus promoting cell senescence. All these events are amplified by the increase of inflammation driven by oxidative stress. Several models of bronchial epithelial cells are used to study the molecular mechanisms and the cellular functions altered by cigarette smoke extract (CSE) exposure, and to test the efficacy of molecules with antioxidant properties. This review offers a comprehensive synthesis of human in-vitro and ex-vivo studies published from 2011 to 2021 describing the molecular and cellular mechanisms evoked by CSE exposure in bronchial epithelial cells, the most used experimental models and the mechanisms of action of cellular antioxidants systems as well as natural and synthetic antioxidant compounds.

The Impact of Muscarinic Receptor Antagonists on Airway Inflammation: A Systematic Review

Long-acting muscarinic receptor antagonists (LAMAs) are the cornerstone for the treatment of chronic obstructive pulmonary disease (COPD); furthermore, tiotropium is approved as add-on therapy in severe asthmatic patients. Accumulating evidence suggests that LAMAs may modulate airway contractility and airway hyperresponsiveness not only by blocking muscarinic acetylcholine receptors (mAchRs) expressed on airway smooth muscle but also via anti-inflammatory mechanisms by blocking mAchRs expressed on inflammatory cells, submucosal glands, and epithelial cells. The aim of this systematic review, performed according to the PRISMA-P guidelines, was to provide a synthesis of the literature on the anti-inflammatory impact of muscarinic receptor antagonists in the airways. Most of the current evidence originates from studies on tiotropium, that demonstrated a reduction in synthesis and release of cytokines and chemokines, as well as the number of total and differential inflammatory cells, induced by different pro-inflammatory stimuli. Conversely, few data are currently available for aclidinium and glycopyrronium, whereas no studies on the potential anti-inflammatory effect of umeclidinium have been reported. Overall, a large body of evidence supports the beneficial impact of tiotropium against airway inflammation. Further well-designed randomized controlled trials are needed to better elucidate the anti-inflammatory mechanisms leading to the protective effect of LAMAs against exacerbations via identifying suitable biomarkers.

Can PBDEs affect the pathophysiologic complex of epithelium in lung diseases?

Brominated flame-retardant (BFRs) exposure promotes multiple adverse health outcomes involved in oxidative stress, inflammation, and tissues damage. We investigated BFR effects, known as polybrominated diphenyl ethers (PBDEs) (47, 99 and 209) in an air-liquid-interface (ALI) airway tissue derived from A549 cell line, and compared with ALI culture of primary human bronchial epithelial cells (pHBEC). The cells, exposed to PBDEs (47, 99 and 209) (0.01-1 μM) for 24 h, were studied for IL-8, Muc5AC and Muc5B (mRNAs and proteins) production, as well as NOX-4 (mRNA) expression. Furthermore, we evaluated tight junction (TJ) integrity by Trans-Epithelial Electrical Resistance (TEER) measurements, and zonula occludens-1 (ZO-1) expression in the cells, and pH variations and rheological properties (elastic G', and viscous G″, moduli) in apical washes of ALI cultures. N-acetylcysteine (NAC) (10 mM) effects were tested in our experimental model of A549 cells. PBDEs (47, 99 and 209) exposure decreased TEER, ZO-1 and pH values, and increased IL-8, Muc5AC, Muc5B (mRNAs and proteins), NOX-4 (mRNA), and rheological parameters (G', G″) in ALI cultures of A549 cell line and pHBEC. NAC inhibited PBDE effects in A549 cells. PBDE inhalation might impairs human health of the lungs inducing oxidative stress, inflammatory response, loss of barrier integrity, unchecked mucus production, as well as altered physicochemical and biological properties of the fluids in airway epithelium. The treatment with anti-oxidants restored the negative effects of PBDEs in epithelial cells.

Cigarette smoke affects the onco-suppressor DAB2IP expression in bronchial epithelial cells of COPD patients

Cigarette smoke is a risk factor for COPD and lung cancer. In cancer, epigenetic modifications affect the expression of Enhancer of Zester Homolog 2 (EZH2), and silenced disabled homolog 2 interacting protein gene (DAB2IP) (onco-suppressor gene) by Histone H3 tri-methylation in lysine 27 (H3K27me3). In"ex vivo"studies, we assessed EZH2, H3K27me3 and DAB2IP immunoreactivity in bronchial epithelial cells from COPD patients (smokers, ex-smokers), Smoker and control subjects. In"in vitro" experiments we studied the effect of cigarette smoke extract (CSE) on EZH2/H3K27me3/DAB2IP expression, apoptosis, invasiveness, and vimentin expression in 16HBE, primary cells, and lung cancer cell lines (A549) long-term exposed to CSE. Finally, in "in vitro"studies, we tested the effect of GSK343 (selective inhibitor of EZH2). EZH2 and H3K27me3 expression was higher, while DAB2IP was lower levels, in bronchial epithelium from COPD and Smokers than in Controls. CSE increased EZH2, H3K27me3 expression and decreased DAB2IP, cell apoptosis and invasiveness in epithelial cells. GSK343 restored the effects of CSE. Cigarette smoke affects EZH2 expression, and reduced DAB2IP via H3K27me3 in COPD patients. The molecular mechanisms associated with EZH2 expression, generate a dysregulation of cell apoptosis, mesenchymal transition, and cell invasiveness in bronchial epithelial cells, encouraging the progression of airway inflammation toward lung cancer in COPD patients.

L-Alpha-glycerylphosphorylcholine can be cytoprotective or cytotoxic in neonatal rat cardiac myocytes: a double-edged sword phenomenon

l-Alpha-glycerylphosphorylcholine (GPC) is a widely used food supplement. GPC has been shown to exert beneficial effects in several organs; however, the cardiac effects of GPC have yet to be investigated. The aim of the present study was therefore to map out the effects of GPC on cardiac myocytes, with or without ischemia–reperfusion insult. Neonatal rat cardiac myocytes were treated with GPC at 1, 10, 80, and 100 µM concentrations for 15 min, 3 h, or 24 h, respectively. Cell viability by calcein assay and the degree of oxidative stress by DHE (superoxide level) and H₂DCF (total ROS accumulation) staining were measured. In separate experiments, cardiomyocytes were pre-treated with the optimal concentration of GPC for 3 h and then cells were exposed to 4 h of simulated ischemia followed by 2 h of reperfusion (SI/R). Cell viability was measured at the end of the SI/R protocol. In normoxic conditions, the 15-min and the 3-h GPC treatment did not affect cell viability, total ROS, and superoxide levels. Under SI/R conditions, the 3-h GPC treatment protected the cardiac myocytes from SI/R-induced cell death and did not alter the level of oxidative stress. The 24-h GPC treatment in normoxic conditions resulted in significant cell death and increased oxidative stress at each concentration. Here we provide the first evidence for the cytoprotective effect of short-term GPC treatment. However, long-term administration of GPC may exert cytotoxicity in a wide concentration range in cardiac myocytes. These results may draw attention to a comprehensive cardiac safety protocol for the testing of GPC.

Current Status of Raf Kinase Inhibitor Protein (RKIP) in Lung Cancer: Behind RTK Signaling

Lung cancer is the most deadly neoplasm with the highest incidence in both genders, with non-small cell lung cancer (NSCLC) being the most frequent subtype. Somatic mutations within the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene are key drivers of NSCLC progression, with EGFR inhibitors being particularly beneficial for patients carrying the so-called “EGFR-sensitizing mutations”. However, patients eventually acquire resistance to these EGFR inhibitors, and a better knowledge of other driven and targetable proteins will allow the design of increasingly accurate drugs against patients’ specific molecular aberrations. Raf kinase inhibitory protein (RKIP) is an important modulator of relevant intracellular signaling pathways, including those controlled by EGFR, such as MAPK. It has been reported that it has metastasis suppressor activity and a prognostic role in several solid tumors, including lung cancer. In the present review, the potential use of RKIP in the clinic as a prognostic biomarker and predictor of therapy response in lung cancer is addressed.

Budesonide, Aclidinium and Formoterol in combination limit inflammaging processes in bronchial epithelial cells exposed to cigarette smoke

Inflammation and cellular senescence (also called inflammaging) are involved in the pathogenesis of premature lung aging, a key driver of chronic obstructive pulmonary disease (COPD). Downregulation of histone deacetylases and FoxO3 expression, activation of the ERK 1/2 pathway and IL-8 increase are hallmarks of lung inflammaging. The effects of Budesonide (BUD), Aclidinium (ACL) and Formoterol (FO) on lung inflammaging are unknown. This study was aimed to assess the effects of BUD, ACL and FO in bronchial epithelial cells exposed to cigarette smoke extract (CSE) by evaluating: a) Expression of TLR4 and survivin and LPS binding by flow cytometry; b) expression of HDAC2, HDAC3, SIRT1 and FoxO3 and activation of the ERK 1/2 pathway by western blot; c) IL-8 mRNA levels and release by Real Time-PCR and ELISA, respectively. Reported results show that CSE increased TLR4 and survivin, LPS binding, ERK 1/2 activation, IL-8 release and mRNA levels but decreased SIRT1, HDAC2, HDAC3 and FoxO3 nuclear expression. Combined therapy with BUD, ACL and FO counteracted the effects of CSE on LPS binding, FoxO3 nuclear expression, ERK 1/2 activation, survivin and IL-8 release and mRNA levels. These findings suggest a new role of combination therapy with BUD, ACL and FO in counteracting inflammaging processes induced by cigarette smoke exposure.

Acetylcholine signaling system in progression of lung cancers

The neurotransmitter acetylcholine (ACh) acts as an autocrine growth factor for human lung cancer. Several lines of evidence show that lung cancer cells express all of the proteins required for the uptake of choline (choline transporter 1, choline transporter-like proteins) synthesis of ACh (choline acetyltransferase, carnitine acetyltransferase), transport of ACh (vesicular acetylcholine transport, OCTs, OCTNs) and degradation of ACh (acetylcholinesterase, butyrylcholinesterase). The released ACh binds back to nicotinic (nAChRs) and muscarinic receptors on lung cancer cells to accelerate their proliferation, migration and invasion. Out of all components of the cholinergic pathway, the nAChR-signaling has been studied the most intensely. The reason for this trend is due to genome-wide data studies showing that nicotinic receptor subtypes are involved in lung cancer risk, the relationship between cigarette smoke and lung cancer risk as well as the rising popularity of electronic cigarettes considered by many as a "safe" alternative to smoking. There are a small number of articles which review the contribution of the other cholinergic proteins in the pathophysiology of lung cancer. The primary objective of this review article is to discuss the function of the acetylcholine-signaling proteins in the progression of lung cancer. The investigation of the role of cholinergic network in lung cancer will pave the way to novel molecular targets and drugs in this lethal malignancy.

Adding a LAMA to ICS/LABA Therapy: A Meta-analysis of Triple Combination Therapy in COPD

BACKGROUND

Inhaled corticosteroid (ICS)/long-acting β₂-agonist (LABA) combination is commonly prescribed to treat COPD; therefore, we performed a meta-analysis on the effect of adding a long-acting muscarinic receptor antagonist (LAMA) to ICS/LABA combination in COPD.

METHODS

Studies were identified by searching in different databases the randomized controlled trials that investigated the effect of ICS/LABA/LAMA combination in COPD. The primary end points were the effect of triple therapy on trough FEV₁, risk of acute exacerbation of COPD (AECOPD), and risk of cardiovascular serious adverse events (SAEs), compared with ICS/LABA combination. The Grading of Recommendations Assessment, Development, and Evaluation system was used to assess the quality of evidence.

RESULTS

Thirteen randomized controlled trials including 15,519 patients with COPD (ICS/LABA/LAMA combination, 53.1%; ICS/LABA combination, 46.9%) were meta-analyzed. ICS/LABA/LAMA combination improved trough FEV₁ (mean difference, +104.86 mL; 95% CI, 86.74-122.99; high quality of evidence) and protected against AECOPD (relative risk, 0.78; 95% CI, 0.71-0.85; high quality of evidence) vs ICS/LABA combination. For every approximately four patients treated with triple therapy, one increased FEV₁ > 100 mL, and approximately 26 patients had to be treated for 1 year with ICS/LABA/LAMA combination to prevent one AECOPD, compared with ICS/LABA combination. Adding a LAMA to ICS/LABA therapy did not modulate the risk of cardiovascular SAEs (moderate quality of evidence).

CONCLUSIONS

Triple therapy provides significant clinical benefit in patients with COPD on ICS/LABA combination. ICS/LABA therapy can be escalated to triple therapy without a real risk to increase cardiovascular SAEs when a LAMA is added to the combination.

TRIAL REGISTRY

ClinicalTrials.gov; No.: CRD42018095300; URL: www.clinicaltrials.gov.

The Cholinergic Pathways in Inflammation: A Potential Pharmacotherapeutic Target for COPD

In COPD, the activity of the cholinergic system is increased, which is one of the reasons for the airflow limitation caused by the contraction of airway smooth muscles. Therefore, blocking the contractive actions with anticholinergics is a useful therapeutic intervention to reduce the airflow limitation. In addition to the effects of bronchoconstriction and mucus secretion, accumulating evidence from animal models of COPD suggest acetylcholine has a role in inflammation. Experiments using muscarinic M₃-receptor deficient mice or M₃ selective antagonists revealed that M₃-receptors on parenchymal cells, but not on hematopoietic cells, are involved in the pro-inflammatory effect of acetylcholine. Recently, combinations of long-acting β2 adrenergic agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) have become available for COPD treatment. These dual long-acting bronchodilators may have synergistic anti-inflammatory effects because stimulation of β2 adrenergic receptors induces inhibitory effects in inflammatory cells via a different signaling pathway from that by antagonizing M₃-receptor, though these anti-inflammatory effects have not been clearly demonstrated in COPD patients. In contrast to the pro-inflammatory effects by ACh via muscarinic receptors, it has been demonstrated that the cholinergic anti-inflammatory pathway, which involves the parasympathetic nervous systems, regulates excessive inflammatory responses to protect organs during tissue injury and infection. Stimulation of acetylcholine via the α7 nicotinic acetylcholine receptor (α7nAChR) exerts inhibitory effects on leukocytes including macrophages and type 2 innate lymphoid cells. Although it remains unclear whether the inhibitory effects of acetylcholine via α7nAChR in inflammatory cells can regulate inflammation in COPD, neuroimmune interactions including the cholinergic anti-inflammatory pathway might serve as potential therapeutic targets.