Smoke-induced Lung Inflammation In Mice Research Articles

Interleukin-41 diminishes cigarette smoke-induced lung inflammation in mice

BackgroundChronic obstructive pulmonary disease (COPD) and other inflammatory lung illnesses are markedly exacerbated by cigarette smoke (CS). The novel cytokine interleukin (IL)-41 has immunoregulatory effects, but data on its function in lung inflammation caused by CS are limited and inconclusive. Our study aimed to investigate the ability of IL-41 to protect against CS-induced lung inflammation in vivo. MethodsIn this model, mice were exposed to six cigarettes three times daily for 1 h, with 4-hour intervals between exposures, for 5 consecutive days. Mice received an intraperitoneal dose of IL-41 or a negative control 1 day prior to their initial exposure to CS. On day 6, mice were sacrificed to assess the impact of IL-41 on CS-induced lung inflammation. ResultsWe found that IL-41 pre-treatment alleviated pulmonary inflammatory infiltration and lung tissue lesions. IL-41 pre-treatment also limited CS-induced weight loss, and resulted in lower numbers of macrophages in the bronchoalveolar lavage fluid and lower percentages of neutrophils and monocytes in the blood. Furthermore, it promoted the polarization of M2 macrophages rather than M1 macrophages, as determined by immunohistochemistry. Consistent with its effects on M2 polarization, pre-treatment with IL-41 was associated with higher levels of IL-10 in the bronchoalveolar lavage fluid and lung tissues of CS-exposed animals and lower production of tumor necrosis factor-α, IL-6 and IL-1β in the serum and lung tissues. ConclusionsThese findings suggest that IL-41 could be used therapeutically to treat CS-induced lung inflammatory disorders as it inhibits CS-induced pulmonary inflammation when administered in vivo in mice.

Interleukin-37 ameliorates cigarette smoke-induced lung inflammation in mice

Cigarette smoking (CS) is the leading cause of chronic obstructive pulmonary disease, and its severity is closely related to lung inflammation. Interleukin (IL)-37 is a newly discovered member of the IL-1 family with anti-inflammatory activity. Our study aimed to elucidate the effect of IL-37 on CS-induced lung inflammation in mice. In this study, mice were exposed to six cigarettes for 1 h three times daily (4 h smoke-free intervals) for 10 consecutive days. Mice were treated intranasally with IL-37-expressing lentivirus and empty lentivirus particles 1 day before the first CS or sham exposure. Mice were sacrificed on day 11 to evaluate the effect of IL-37 on CS-induced pulmonary inflammation in mice. Administering IL-37-expressing lentivirus significantly reduced CS-induced weight loss in mice compared to empty lentivirus controls (P < 0.05). Histological analysis showed that IL-37 significantly alleviated inflammatory cell recruitment, alveolar septum enlargement, alveolar wall attenuation, mucus hypersecretion, and goblet cell metaplasia in mouse lungs (P < 0.001). IL-37 expression also significantly inhibited CS-induced increases in inflammatory cells (including lymphocytes, neutrophils, and macrophages) in mouse lungs (P < 0.05), as well as pro-inflammatory cytokines such as IL-1β, IL-6, IL-17, monocyte chemotactic protein-1 and tumor necrosis factor-α production (P < 0.05). IL-37 also significantly reduced myeloperoxidase activity in mouse serum (P < 0.01) and lung tissues (P < 0.001). Therefore, IL-37 can ameliorate CS-induced pulmonary inflammation in mice and IL-37 may be a potential therapeutic strategy for CS-induced lung inflammatory diseases.

Ebselen abolishes vascular dysfunction in influenza A virus-induced exacerbations of cigarette smoke-induced lung inflammation in mice.

People with chronic obstructive pulmonary disease (COPD) are susceptible to respiratory infections which exacerbate pulmonary and/or cardiovascular complications, increasing their likelihood of death. The mechanisms driving these complications remain unknown but increased oxidative stress has been implicated. Here we investigated whether influenza A virus (IAV) infection, following chronic cigarette smoke (CS) exposure, worsens vascular function and if so, whether the antioxidant ebselen alleviates this vascular dysfunction. Male BALB/c mice were exposed to either room air or CS for 8 weeks followed by inoculation with IAV (Mem71, 1 × 104.5 pfu). Mice were treated with ebselen (10 mg/kg) or vehicle (5% w/v CM-cellulose in water) daily. Mice were culled 3- and 10-days post-infection, and their lungs lavaged to assess inflammation. The thoracic aorta was excised to investigate endothelial and smooth muscle dilator responses, expression of key vasodilatory and oxidative stress modulators, infiltrating immune cells and vascular remodelling. CS increased lung inflammation and caused significant vascular endothelial dysfunction, which was worsened by IAV infection. CS-driven increases in vascular oxidative stress, aortic wall remodelling and suppression of endothelial nitric oxide synthase (eNOS) were not affected by IAV infection. CS and IAV infection significantly enhanced T cell recruitment into the aortic wall. Ebselen abolished the exaggerated lung inflammation, vascular dysfunction and increased T cell infiltration in CS and IAV-infected mice. Our findings showed that ebselen treatment abolished vascular dysfunction in IAV-induced exacerbations of CS-induced lung inflammation indicating it may have potential for the treatment of cardiovascular comorbidities seen in acute exacerbations of COPD (AECOPD).

Astragaloside IV suppresses inflammatory response via suppression of NF-κB, and MAPK signalling in human bronchial epithelial cells

Context Astragaloside IV isolated from Astragalus membranaceus (Fisch.), which was reported to have anti-tumor, anti-asthma, and suppressed cigarette smoke-induced lung inflammation in mice. Objectives This study investigated whether astragaloside IV reduced the expression of inflammatory mediators and oxidative stress in BEAS-2B cells. Methods BEAS-2B cells treated with astragaloside IV, and then stimulated with TNF-α or TNF-α/IL-4. The levels of cytokine and chemokine were analysed with ELISA and real-time PCR. Results Astragaloside IV significantly inhibited the levels of CCL5, MCP-1, IL-6 and IL-8. Astragaloside IV also reduced ICAM-1 expression for blocked THP-1 monocyte adhesion to BEAS-2B cells. Furthermore, astragaloside IV attenuated the phosphorylation of MAPK, and reduced the translocation of p65 into the nucleus. Astragaloside IV could increase the expression of HO-1 and Nrf2 for promoting the oxidant protective effect. Conclusion Aastragaloside IV has an anti-inflammatory and oxidative effect via regulated NF-κB, MAPK and HO-1/Nrf2 signalling pathways in human bronchial epithelial cells.

Ameliorative effect of acetylshikonin on cigarette smoke-induced lung inflammation in mice

Cigarette smoke exposure is the major cause of chronic obstructive pulmonary disease (COPD). Acetylshikonin was the active principle component of Purple Gromwell that show anti-oxidative and anti-inflammatory effect. However, no data are available to elucidate the protective effect of acetylshikonin on COPD. Acetylshikonin could attenuate smoke-induced lung pathological changes, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and monocyte chemoattractant protein 1 (MCP-1) productions, and tissue damages caused by oxidative stress. Furthermore, acetylshikonin was found to enhance the expression of Nrf2 and Nur77-mediated COX-2 in vivo and in vitro.

Losartan does not inhibit cigarette smoke-induced lung inflammation in mice

Chronic Obstructive Pulmonary Disease (COPD) is a progressive lung disease largely caused by cigarette smoking (CS) and is characterized by lung inflammation and airflow limitation that is not fully reversible. Approximately 50% of people with COPD die of a cardiovascular comorbidity and current pharmacological strategies provide little benefit. Therefore, drugs that target the lung and the cardiovascular system concurrently may be an advantageous therapeutic strategy. The aim of this study was to see whether losartan, an angiotensin-II AT1a receptor antagonist widely used to treat hypertension associated with cardiovascular disease, protects against CS-induced lung inflammation in mice. Male BALB/c mice were exposed to CS for 8 weeks and treated with either losartan (30 mg/kg) or vehicle daily. Mice were euthanized and bronchoalveolar lavage fluid (BALF) inflammation, and whole lung cytokine, chemokine and protease mRNA expression assessed. CS caused significant increases in BALF total cells, macrophages, neutrophils and whole lung IL-6, TNF-α, CXCL-1, IL-17A and MMP12 mRNA expression compared to sham-exposed mice. However, losartan only reduced CS-induced increases in IL-6 mRNA expression. Angiotensin-II receptor expression was reduced in lung tissue from CS-exposed mice. In conclusion, losartan did not inhibit CS-induced BALF cellularity despite reducing whole lung IL-6 mRNA and Ang-II receptor expression.

Interleukin-35 expression protects against cigarette smoke-induced lung inflammation in mice

Cigarette smoke (CS) is a very important cause of pulmonary inflammatory diseases. Interleukin (IL)-35 is a novel anti-inflammatory cytokine but its role in CS-mediated lung inflammation remains unclear. In the present study, we examined the effect of IL-35 expression on CS-induced lung inflammation in mice. A plasmid DNA expressing IL-35 was injected into mice via a hydrodynamic-based gene delivery that were subsequently exposed to CS three times a day for 5 days. We found that IL-35 expression inhibited pulmonary inflammatory infiltration, lung tissue lesions, mucus secretion, and myeloperoxidase activity in CS-treated mice. Moreover, IL-35 expression decreased the production of IL-1β, tumor necrosis factor-α, IL-6, and IL-17, but increased the level of IL-10 in bronchoalveolar lavage fluids and lung tissues from CS-challenged mice. These results suggest that in vivo expression of IL-35 can protect against CS-induced lung inflammation and may be a therapeutic target in CS-related pulmonary diseases.

Platycodin D protects against cigarette smoke-induced lung inflammation in mice

Cigarette smoke is the one of the major factors that leads to chronic obstructive pulmonary disease (COPD). Inflammation and oxidant stress have been known to play critical roles in the development of COPD. Platycodin D (PLD) has been reported to have anti-inflammatory and anti-oxidant effects. In this study, we aimed to investigate the protective effects of PLD on cigarette smoke (CS)-induced lung inflammation in mice. PLD was adminstrated i.p. to mice 2h before CS exposure daily for five consecutive days. The production of inflammatory cytokines TNF-α and IL-1β were measured by ELISA. The levels of malonaldehyde (MDA) and nitric oxide (NO) were also detected in this study. The expression of nuclear factor-erythroid 2–related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NF-κB, and IκBα were detected by western blot analysis. The results showed that PLD significantly attenuated CS-induced lung pathological changes, inflammatory cells infiltration, as well as TNF-α and IL-1β production. CS-induced MDA and NO production were also inhibited by treatment of PLD. Western blot analysis showed that PLD significantly suppressed CS-induced NF-κB activation. In addition, PLD was found to increase the expression of Nrf2 and HO-1. Taken together, these results indicated that PLD protected against CS-induced lung inflammation by inhibiting inflammatory and oxidative response through activating Nrf2 signaling pathway. PLD might be an effective treatment for CS-induced lung inflammation.

Innate cellular sources of interleukin-17A regulate macrophage accumulation in cigarette- smoke-induced lung inflammation in mice.

Cigarette smoke (CS) is the major cause of chronic obstructive pulmonary disease (COPD). Interleukin-17A (IL-17A) is a pivotal cytokine that regulates lung immunity and inflammation. The aim of the present study was to investigate how IL-17A regulates CS-induced lung inflammation in vivo. IL-17A knockout (KO) mice and neutralization of IL-17A in wild-type (WT) mice reduced macrophage and neutrophil recruitment and chemokine (C-C motif) ligand 2 (CCL2), CCL3 and matrix metalloproteinase (MMP)-12 mRNA expression in response to acute CS exposure. IL-17A expression was increased in non-obese diabetic (NOD) severe combined immunodeficiency SCID) mice with non-functional B- and T-cells over a 4-week CS exposure period, where macrophages accumulated to the same extent as in WT mice. Gene expression analysis by QPCR (quantitative real-time PCR) of isolated immune cell subsets detected increased levels of IL-17A transcript in macrophages, neutrophils and NK/NKT cells in the lungs of CS-exposed mice. In order to further explore the relative contribution of innate immune cellular sources, intracellular IL-17A staining was performed. In the present study, we demonstrate that CS exposure primes natural killer (NK), natural killer T (NKT) and γδ T-cells to produce more IL-17A protein and CS alone increased the frequency of IL17+ γδ T-cells in the lung, whereas IL-17A protein was not detected in macrophages and neutrophils. Our data suggest that activation of innate cellular sources of IL-17A is an essential mediator of macrophage accumulation in CS-exposed lungs. Targeting non-conventional T-cell sources of IL-17A may offer an alternative strategy to reduce pathogenic macrophages in COPD.

Forsythiaside inhibits cigarette smoke-induced lung inflammation by activation of Nrf2 and inhibition of NF-κB

Cigarette smoke has been reported to be the major cause of chronic obstructive pulmonary disease (COPD). It causes persistent inflammation by regulating the redox-sensitive pathways. Forsythiaside, an active constituent isolated from the Chinese medicinal herb Forsythia suspensa, has been reported to have anti-inflammatory and anti-oxidant effects. Thus, in this study, we investigated the protective effects of forsythiaside against cigarette smoke-induced lung inflammation in mice. COPD mice model was established by cigarette smoke. Forsythiaside was given 2h before cigarette smoke exposure for five consecutive days. Bronchoalveolar lavage fluid and lung tissues were collected to assess pathological changes, lipid peroxidation, inflammatory cytokine production, Nrf-2, and NF-κB expression. Our results showed that forsythiaside attenuated the infiltration of inflammatory cells, NO and inflammatory cytokines TNF-α, IL-6 and IL-1β production, and reversed the CS-induced decrease of glutathione/glutathione disulfide (GSH/GSSG) ratio. Western blot analysis showed that forsythiaside inhibited cigarette smoke-induced NF-κB activation. In addition, forsythiaside dose-dependently up-regulated the expression of Nrf2 and HO-1. In conclusion, forsythiaside protected against cigarette smoke-induced lung injury through activating Nrf2 and inhibiting NF-κB signaling pathway.

Disruption of pulmonary lipid homeostasis drives cigarette smoke-induced lung inflammation in mice.

Overwhelming evidence links inflammation to the pathogenesis of smoking-related pulmonary diseases, especially chronic obstructive pulmonary disease (COPD). Despite an increased understanding of the disease pathogenesis, mechanisms initiating smoking-induced inflammatory processes remain incompletely understood. To investigate the mechanisms that initiate and propagate smoke-induced inflammation, we used a well-characterised mouse model of cigarette smoke exposure, mice deficient for interleukin (IL)-1α, IL-1β and Toll-like receptor 4, and antibodies blocking granulocyte-macrophage colony-stimulating factor (GM-CSF). Studies were also pursued using intranasal delivery of human oxidised low-density lipoprotein (hOxLDL), a source of oxidised lipids, to investigate the inflammatory processes associated with impaired lipid homeostasis. We found that cigarette smoke exposure rapidly led to lipid accumulation in pulmonary macrophages, a defining feature of foam cells, which in turn released high levels of IL-1α. In smoke-exposed IL-1α-deficient mice, phospholipids accumulated in the bronchoalveolar lavage, a phenomenon also observed when blocking GM-CSF. Intranasal administration of hOxLDL led to lipid accumulation in macrophages and initiated an inflammatory process that mirrored the characteristics of cigarette smoke-induced inflammation. These findings identify a link between lipid accumulation in macrophages, inflammation and damaged surfactant, suggesting that the response to damaged pulmonary surfactant is a central mechanism that drives cigarette smoke-induced inflammation. Further investigations are required to explore the role of distorted lipid homeostasis in the pathogenesis of COPD.

Anti-interleukin-33 inhibits cigarette smoke-induced lung inflammation in mice.

The mechanism by which cigarette smoke (CS) causes chronic obstructive pulmonary disease (COPD) is poorly understood. Interleukin-33 (IL-33) is a pleiotropic cytokine predominantly expressed in lung tissue and can elicit airway inflammation in naive mice. We tested the hypothesis that IL-33 is induced by CS and contributes to CS-mediated airway inflammation in a mouse model of CS-induced COPD. Groups of mice were exposed to CS three times per day for 4 consecutive days. The expression levels of IL-33 and ST2 were markedly enhanced in the lung tissue of mice inhaling CS. Exposure to CS also induced neutrophil and macrophage infiltration and expression of inflammatory cytokines (IL-1β, tumour necrosis factor-α, IL-17), chemokines (monocyte chemoattractant protein-1) and mucin 5, subtypes A and C in the airways. More importantly, all of these CS-induced pathogenic changes were significantly inhibited by treatment with neutralizing anti-IL-33 antibody delivered intranasally. Hence, our results suggest that IL-33 plays a critical role in CS-mediated airway inflammation and may be a therapeutic target in CS-related diseases, including COPD.

Glutathione peroxidase-1 protects against cigarette smoke-induced lung inflammation in mice

Reactive oxygen species (ROS) produced from cigarette smoke cause oxidative lung damage including protein denaturation, lipid peroxidation, and DNA damage. Glutathione peroxidase-1 (gpx-1) is a detoxifying enzyme that may protect lungs from such damage. The aim of this study was to determine whether gpx-1 protects the lung against oxidative stress-induced lung inflammation in vivo. Male wild-type (WT) or gpx-1(-/-) mice were exposed to cigarette smoke generated from nine cigarettes per day for 4 days to induce oxidative stress and lung inflammation. The effect of the gpx mimetic ebselen on cigarette smoke-induced lung inflammation was evaluated when given prophylactically and therapeutically, i.e., during established inflammation. Mice were killed, and the lungs were lavaged with PBS and then harvested for genomic and proteomic analysis. Gpx-1(-/-) mice exposed to cigarette smoke had enhanced BALF neutrophils, macrophages, proteolytic burden, whole lung IL-17A, and MIP1alpha mRNA compared with WT mice. The gpx mimetic ebselen (10 and 100 microM) inhibited cigarette smoke extract-induced oxidation of MH-S cells in vitro and inhibited cigarette smoke-induced increases in BALF macrophages, neutrophils, proteolytic burden, and macrophage and neutrophil chemotactic factor gene expression when administered prophylactically. In addition, ebselen inhibited established BALF inflammation when administered therapeutically. These data show that gpx-1 protects against cigarette smoke-induced lung inflammation, and agents that mimic the actions of gpx-1 may have therapeutic utility in inflammatory lung diseases where cigarette smoke plays a role.

A multi-target antisense approach against PDE4 and PDE7 reduces smoke-induced lung inflammation in mice

BackgroundRecent development in the field of COPD has focused on strategies aimed at reducing the underlying inflammation through selective inhibition of the phosphodiesterase type IV (PDE4) isoform. Although the anti-inflammatory and bronchodilator activity of selective PDE4 inhibitors has been well documented, their low therapeutic ratio and dose-dependent systemic side effects have limited their clinical utility. This study examined the effect of 2'-deoxy-2'-Fluoro-β-D-Arabinonucleic Acid (FANA)-containing antisense oligonucleotides (AON) targeting the mRNA for the PDE4B/4D and 7A subtypes on lung inflammatory markers, both in vitro and in vivo.MethodsNormal human bronchial epithelial (NHBE) cells were transfected with FANA AON against PDE4B/4D and 7A alone or in combination. mRNA levels for target PDE subtypes, as well as secretion of pro-inflammatory chemokines were then measured following cell stimulation. Mice were treated with combined PDE4B/4D and 7A AON via endo-tracheal delivery, or with roflumilast via oral delivery, and exposed to cigarette smoke for one week. Target mRNA inhibition, as well as influx of inflammatory cells and mediators were measured in lung lavages. A two-week smoke exposure protocol was also used to test the longer term potency of PDE4B/4D and 7A AONs.ResultsIn NHBE cells, PDE4B/4D and 7A AONs dose-dependently and specifically inhibited expression of their respective target mRNA. When used in combination, PDE4B/4D and 7A AONs significantly abrogated the cytokine-induced secretion of IL-8 and MCP-1 to near baseline levels. In mice treated with combined PDE4B/4D and 7A AONs and exposed to cigarette smoke, significant protection against the smoke-induced recruitment of neutrophils and production of KC and pro-MMP-9 was obtained, which was correlated with inhibition of target mRNA in cells from lung lavages. In this model, PDE AONs exerted more potent and broader anti-inflammatory effects against smoke-induced lung inflammation than roflumilast. Moreover, the protective effect of PDE4B/4D and 7A AON was maintained when a once-weekly treatment schedule was used.ConclusionThese results indicate that inhaled AON against PDE4B/4D and 7A have unique effects on biomarkers that are believed to be important in the pathophysiology of COPD, which supports further development as a potential therapy in this disease.