Probing Cellular and Molecular Mechanisms of Cigarette Smoke-Induced Immune Response in the Progression of Chronic Obstructive Pulmonary Disease Using Multiscale Network Modeling

The Involvement of PDE4 in the Protective Effects of Melatonin on Cigarette-Smoke-Induced Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a significant disease threatening human health. Currently, roflumilast, a phosphodiesterase (PDE)4 inhibitor, is recommended as a therapeutic agent for COPD. In this study, we investigated the therapeutic effects of melatonin against COPD, focusing on determining whether it is a PDE4 inhibitor via in vivo and in vitro experiment using cigarette smoke (CS) and cigarette smoke condensate (CSC), respectively. In the in vivo experiments, melatonin treatment reduced inflammatory responses, including inflammatory cell counts. Melatonin treatment also suppressed the CS-exposure-induced upregulation of cytokine and matrix metalloproteinase (MMP)-9, reduced the PDE4B expression, and elevated cAMP levels. In addition, these effects were synergistic, as melatonin and roflumilast cotreatment eventually ameliorated the CS-exposure-induced worsening of lung function. In the CSC-stimulated NCI-H292 cells, melatonin inhibited elevation in the levels of inflammatory cytokines, MMP-9, and PDE4, and elevated cAMP levels. Furthermore, melatonin and roflumilast cotreatment was more effective on inflammatory responses than only melatonin or roflumilast treatment. Our results indicate that melatonin relieves inflammatory response and loss of lung function in COPD, which is associated with decreased PDE4 expression. Therefore, we suggest that melatonin is a putative candidate for the treatment of COPD.

Inflammatory parameters and pulmonary biomarkers in smokers with and without chronic obstructive pulmonary disease (COPD)

Background

We organized this study in order to investigate differences in serum inflammatory profiles and circulating serum pneumoproteins between smokers with and without chronic obstructive pulmonary disease (COPD).

Methods

Patients aged 35–70 years with COPD and a smoking history ≥10 pack-years (cases, n=38) and 38 participants with the same smoking history without COPD (controls) were included in a comparative study conducted as part of a population-based cross-sectional study with 2,388 individuals in northwestern Russia. Cases and controls were matched for age and smoking history. Airflow obstruction (AO) was defined using forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) <0.70 and/or FEV1/FVC < lower limit of the normal cut-off values. Patients at risk for COPD were reassessed using a standardized diagnostic work-up protocol. Several parameters, among which four inflammatory biomarkers [the high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) levels] and two pneumoproteins [surfactant protein D (SP-D) and Clara cell secretory protein 16 (CC16)], were measured in the peripheral blood. Systemic inflammation was defined as at least 2 or more elevated biomarker levels.

Results

Out of all smokers, 57.9% with normal spirometry and 36.8% with COPD did not have systemic inflammation, whereas 44.7% of the patients with COPD and 5.3% of the patients without AO demonstrated at least two elevated biomarker levels. No difference in age, gender, and smoking history, environmental and occupational exposure was found between the non-inflamed and the inflamed smokers. Of all risk factors studied, only COPD was associated with systemic inflammation [odds ratio (OR) 11.42, 95% confidence interval (CI): 2.13–58.84].

Conclusions

Our study describes the systemic inflammatory network pattern associated with COPD and how it differs from the pattern in smokers with normal lung function. Systemic inflammation is not present in all smokers with COPD; in contrast, some non-obstructed smokers are characterized by systemic inflammation. From this perspective, smoking itself could be seen as a disease and studied accordingly.

Trial Registration

NCT02307799.

The antioxidant N-acetylcysteine promotes immune response and inhibits epithelial-mesenchymal transition to alleviate pulmonary fibrosis in chronic obstructive pulmonary disease by suppressing the VWF/p38 MAPK axis

Background/aim

N-Acetylcysteine (NAC) demonstrates applications in the prevention of exacerbation of chronic obstructive pulmonary disease (COPD). COPD is often characterized by fibrosis of the small airways. This study aims at investigating the physiological mechanisms by which NAC might mediate the pulmonary fibrosis in COPD.

Methods

A total of 10 non-smokers without COPD and 10 smokers with COPD were recruited in this study, and COPD rat models were established. Cigarette smoke extract (CSE) cell models were constructed. The gain- or loss-of-function experiments were adopted to determine the expression of VWF and the extent of p38 MAPK phosphorylation, levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and immunoglobulins (IgG, IgM and IgA) in the serum of COPD rats and supernatant of alveolar epithelial cells and to detect cell invasion and migration and the ratio of CD3⁺, CD4⁺, CD8⁺ and CD4⁺/CD8⁺T lymphocytes.

Results

Expression of VWF and the extent of p38 MAPK phosphorylation were increased in COPD. NAC inhibited p38 MAPK phosphorylation by reducing the VWF expression. NAC could inhibit cell migration and invasion, elevate E-cadherin expression, the ratio of CD3⁺, CD4⁺, CD8⁺ and CD4⁺/CD8⁺T lymphocytes, and levels of IgG, IgA, and IgM, and reduce N-cadherin expression and levels of IL-6 and TNF-α in CSE cells and serum of COPD rats. NAC promoted immune response and suppressed epithelial-mesenchymal transformation (EMT) to relieve COPD-induced pulmonary fibrosis in vitro and in vivo by inhibiting the VWF/p38 MAPK axis.

Conclusions

Collectively, NAC could ameliorate COPD-induced pulmonary fibrosis by promoting immune response and inhibiting EMT process via the VWF/p38 MAPK axis, therefore providing us with a potential therapeutic target for treating COPD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00342-y.

Alteration of immune profiles is associated with pulmonary function and symptoms in patients with chronic obstructive pulmonary disease

Inflammation serves a key role in chronic obstructive pulmonary disease (COPD). However, changes in the immune profiles of patients with COPD remain unclear. The present prospective observational study aimed to determine the expression profiles of immune cells and inflammatory factors of patients with COPD and healthy controls, and to analyze the relationship between immune profiles and smoking history. A total of 140 subjects were enrolled in the present study between September 2018 and April 2019 at West China Hospital of Sichuan University (Chengdu, China). These included 87 patients with stable COPD and 24 patients with acute exacerbated COPD, as well as 29 healthy controls. Baseline characteristics were recorded during the screening period, and levels of immune cells were examined using flow cytometry. In addition, levels of inflammatory factors were measured using ELISAs. The results revealed increased expression of the CD64⁺/CD14⁺ mononuclear phagocyte system (MPS) and CD16⁺CD66⁺ neutrophils, and decreased expression of CD3⁺CD4⁺ T cells and CD3⁺ CD8⁺ T cells (all P<0.05) in the peripheral blood of patients with COPD and smokers relative to non-smoking controls. In addition, significant differences were observed in protein levels of IL-6, IL-1β, TNF-α, TGF-α, IFN-γ, IL-8, IL-17A and CRP among the three groups (all P<0.05). Furthermore, the IL-17A, TNF and NF-κB signaling pathways were found to serve a key role in the inflammatory network of COPD. Pearson's correlation analysis revealed a positive correlation between CD3⁺T lymphocyte counts and pulmonary function, and a negative correlation with smoking and exacerbations. Furthermore, neutrophils and MPS were negatively associated with pulmonary function, and IL-8 was positively associated with cough. There was also a negative association between CRP and IL-17A with pulmonary function but a positive correlation with symptoms and exacerbation. Club cell secretory protein was also negatively associated with emphysema parameters. In conclusion, the present findings revealed significant differences in profiles of immune factors among patients with COPD, smokers and non-smoking controls and their association with clinical characteristics. The clinical trial registration number of the present study is: ChiCTR1800015700 (registered with http://www.chictr.org.cn/index.aspx, 2018/04/16).

PI3K signalling in chronic obstructive pulmonary disease and opportunities for therapy

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterised by airway inflammation and progressive obstruction of the lung airflow. Current pharmacological treatments include bronchodilators, alone or in combination with steroids, or other anti-inflammatory agents, which have only partially contributed to the inhibition of disease progression and mortality. Therefore, further research unravelling the underlying mechanisms is necessary to develop new anti-COPD drugs with both lower toxicity and higher efficacy. Extrinsic signalling pathways play crucial roles in COPD development and exacerbations. In particular, phosphoinositide 3-kinase (PI3K) signalling has recently been shown to be a major driver of the COPD phenotype. Therefore, several small-molecule inhibitors have been identified to block the hyperactivation of this signalling pathway in COPD patients, many of them showing promising outcomes in both preclinical animal models of COPD and human clinical trials. In this review, we discuss the critically important roles played by hyperactivated PI3K signalling in the pathogenesis of COPD. We also critically review current therapeutics based on PI3K inhibition, and provide suggestions focusing on PI3K signalling for the further improvement of the COPD phenotype. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Testosterone attenuates pulmonary epithelial inflammation in male rats of COPD model through preventing NRF1-derived NF-κB signaling

Testosterone deficiency is common in male patients with chronic obstructive pulmonary disease (COPD) and may correlate with the deterioration of COPD. Clinical research suggests that testosterone replacement therapy may slow the COPD progression, but the specific biological pathway remains unclear. In this study, we explored the effect of testosterone on pulmonary inflammation in male COPD rats. The animals were co-treated with lipopolysaccharide (LPS) and cigarette to induce COPD. In COPD rats, nuclear respiratory factor 1 (NRF1) and NF-κB p65 were upregulated. In cigarette smoke extract (CSE)-, LPS-, or the combination of CSE and LPS-treated L132 cells, NRF1 and p65 were also upregulated. Silencing NRF1 resulted in the downregulation of p65. ChIP‒seq, ChIP‒qPCR, and luciferase results showed that NRF1 transcriptionally regulated p65. Both male and female COPD rats showed an upregulated NRF1 level and similar pulmonary morphology. But NRF1 was further upregulated in male castrated rats. Further supplementing testosterone in castrated male rats significantly reduced NRF1, pulmonary lesions, and inflammation. Supplementation of testosterone also reduced the phosphorylation of p65 and IKKβ induced by LPS or CSE in L132 cells. Our results suggest that testosterone plays a protective role in pulmonary epithelial inflammation of COPD through inhibition of NRF1-derived NF-κB signaling and the phosphorylation of p65.

MiR-195-5p inhibits the development of chronic obstructive pulmonary disease via targeting siglec1

Chronic obstructive pulmonary disease (COPD), characterized by chronic inflammation, is a recognized global health crisis. Sialic acid-binding immunoglobulin-like lectin 1 (siglec1 or CD169), mainly expressed in macrophages and dendritic cells, is markedly upregulated after encountering pathogens or under acute/chronic inflammation conditions. However, it is rarely reported that whether siglec1 plays a role in the development of COPD. In this study, we found that siglec1 had higher expression in the lungs from COPD rats and in peripheral blood mononuclear cells (PBMCs) from COPD patients. Knockdown of siglec1 in vivo and in vitro dramatically decreased pro-inflammatory cytokines production in pulmonary macrophages and alleviated pulmonary inflammatory responses in COPD rats as well as inactivated nuclear factor kappa B (NF-κB) signaling. In addition, we identified a new microRNA, miR-195-5p, which has never explored in COPD, was lower expressed in COPD rats and PBMC of COPD patients, and could negatively modulate siglec1 expression in macrophages. Moreover, overexpression of miR-195-5p via miR-195-5p mimics in vitro and in vivo could significantly alleviate pro-inflammatory cytokines production in pulmonary macrophages and pulmonary inflammatory responses in COPD rats. Together, our findings suggested that miR-195-5p inhibited the development of COPD via targeting siglec1, which might become a therapeutic target to improve COPD.

Surfactant protein A expression and distribution in human lung samples from smokers with or without chronic obstructive pulmonary disease in China

Cigarette smoking is considered the main risk factor for chronic obstructive pulmonary disease (COPD), although the mechanism remains unknown. surfactant protein A (SP-A) is thought to protect the lung from smoking-induced damage, but related studies performed in China are scarce. The aim of the study is to assess alterations of SP-A expression and distribution in lung samples from Chinese smokers with or without COPD.This cross-sectional study assessed 45 men in Wuhan Tongji Hospital after lobectomy for lung cancer in June 2010 to September 2010. Peripheral lung specimens were collected from control nonsmokers without airflow obstruction (nonsmoking group, n = 15), smokers without airflow obstruction (smoking group, n = 15), and patients with COPD (COPD group, n = 15). SP-A expression levels in lung tissue samples and its distribution in lung cells, type II pneumocytes (PNII), and alveolar macrophages (MACR) were determined by immunoblotting and immunohistochemistry.SP-A levels were significantly decreased in the COPD group (1.00 ± 0.25) compared with the smoking (2.31 ± 0.64) and nonsmoking (8.03 ± 2.80) groups; the smoking group also showed significantly reduced levels compared with the nonsmoking group (P < .05). PNII expressing SP-A were less abundant in the COPD group (39.3% ± 7.1%) compared with the smoking group (76.2% ± 29.8%), whereas SP-A MACR were more abundant (92.4% ± 7.1% vs 68.5% ± 20.2%) (all P < .05). Among the 30 smokers, forced expiratory volume in one second (% predicted) was positively correlated with SP-A levels (r = 0.739) and the rate of SP-A+ PNII (r = 0.811), and negatively correlated with the rate of SP-A+ MACR (r = -0.758) (all P < .05).Changes in SP-A expression and distribution in lung tissues may be involved in COPD pathogenesis in smokers.

Systemic biomarkers of inflammation, oxidative stress and tissue injury and repair among waterpipe, cigarette and dual tobacco smokers

BACKGROUND

Waterpipe tobacco (WPT) smoking is associated with deleterious effects on cardio-pulmonary systems which may have adverse repercussions in pathophysiology and progression of chronic lung and cardiovascular diseases. We compared the biomarkers of systemic inflammation, lipid mediators, injury/repair and oxidative stress between groups of non-smokers (NS), exclusive WPT smokers (WPS), exclusive cigarette smokers (CS) and dual WPS and CS (DS).

METHODS

Two cohorts were recruited. Cohort I consisted of WPS (n=12), CS (n=26), DS (n=10) and NS (n=25). Cohort II consisted of WPS (n=33) and NS (n=24). Plasma and urine samples were collected and analysed for various systemic biomarkers.

RESULTS

Compared with NS, plasma levels of inflammatory mediators (interleukin (IL)-6, IL-8, IL1β and tumor necrosis factor-α) were significantly higher in WPS and CS, and were further augmented in DS. Endothelial biomarkers (intracellular adhesion molecule-1, prostaglandin E-2 and metalloproteinase-9) were significantly higher in CS. Most notably, pro-resolving lipid mediator (resolvin E1) and biomarkers of immunity, tissue injury, and repair were significantly lower in WPS and CS. Urinary levels of 8-isoprostane were significantly higher in all smoking groups in cohort I, while 8-isoprostane, myeloperoxidase, receptor for advanced glycation end products (RAGE), En-RAGE and matrix metalloproteinase-9 were significantly higher in all smoking groups in cohort II.

CONCLUSIONS

Biomarkers of inflammation, oxidative stress, immunity, tissue injury and repair were elevated in WPS and CS groups. Furthermore, concurrent use of WPT and cigarettes is more harmful than cigarette or WPT smoking alone. These data may help inform the public and policy-makers about the dangers of WPT smoking and dual use of tobacco products.

Risk of community-acquired pneumonia in chronic obstructive pulmonary disease stratified by smoking status: a population-based cohort study in the United Kingdom

BACKGROUND

Smoking increases the risk of community-acquired pneumonia (CAP) and is associated with the development of COPD. Until now, it is unclear whether CAP in COPD is due to smoking-related effects, or due to COPD pathophysiology itself.

OBJECTIVE

To evaluate the association between COPD and CAP by smoking status.

METHODS

In total, 62,621 COPD and 191,654 control subjects, matched by year of birth, gender and primary care practice, were extracted from the Clinical Practice Research Datalink (2005-2014). Incidence rates (IRs) were estimated by dividing the total number of CAP cases by the cumulative person-time at risk. Time-varying Cox proportional hazard models were used to estimate the hazard ratios (HRs) for CAP in COPD patients versus controls. HRs of CAP by smoking status were calculated by stratified analyses in COPD patients versus controls and within both subgroups with never smoking as reference.

RESULTS

IRs of CAP in COPD patients (32.00/1,000 person-years) and controls (6.75/1,000 person-years) increased with age and female gender. The risk of CAP in COPD patients was higher than in controls (HR 4.51, 95% CI: 4.27-4.77). Current smoking COPD patients had comparable CAP risk (HR 0.92, 95% CI: 0.82-1.02) as never smoking COPD patients (reference), whereas current smoking controls had a higher risk (HR 1.23, 95% CI: 1.13-1.34) compared to never smoking controls.

CONCLUSION

COPD patients have a fourfold increased risk to develop CAP, independent of smoking status. Identification of factors related with the increased risk of CAP in COPD is warranted, in order to improve the management of patients at risk.