Pulmonary catabolism of interleukin 6 evaluated by lung perfusion of normal and smoker rats

A standardized bark extract of Pinus pinaster Aiton (Pycnogenol®) attenuated chronic obstructive pulmonary disease via Erk-sp1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

A standardized bark extract of Pinus pinaster Aiton (Pycnogenol^®; PYC) used as an herbal medicine to treat various diseases in Europe and North America.

AIM OF THE STUDY

This study evaluates the ability of PYC to inhibit chronic obstructive pulmonary disease (COPD) in the cigarette smoke extract (CSE)-stimulated human airway epithelial cell line NCI-H292 and in a cigarette smoke (CS) and lipopolysaccharide (LPS)-induced mouse model.

METHODS

To induce COPD, the mice intranasally received LPS on day 4 and were exposed to CS for 1h per day (total eight cigarettes per day) from days 1-7. The mice were administered PYC at a dose of 15mg/kg and 30mg/kg 1h before CS exposure.

RESULTS

In the CSE-stimulated NCI-H292 cells, PYC significantly inhibited Erk phosphorylation, sp1 expression, MUC5AC, and pro-inflammatory cytokines in a concentration-dependent manner, as evidenced by a reduction in their mRNA levels. Co-treatment with PYC and Erk inhibitors markedly reduced the levels inflammatory mediators compared to only PYC-treatment. In the COPD mice model, PYC decreased the inflammatory cell count and the levels of pro-inflammatory cytokines in the broncho-alveolar lavage fluid compared with COPD mice. PYC attenuated the recruitment of inflammatory cells in the airways and decreased the expression levels of Erk phosphorylation and sp1. PYC also inhibited the expression of myeloperoxidase and matrix metalloproteinases-9 in lung tissue.

CONCLUSION

Our results indicate that PYC inhibited the reduction in the inflammatory response in CSE-stimulated NCI-H292 cells and the COPD mouse model via the Erk-sp1 pathway. Therefore, we suggest that PYC has the potential to treat COPD.

Induction of the interleukin 6/ signal transducer and activator of transcription pathway in the lungs of mice sub-chronically exposed to mainstream tobacco smoke

Background

Tobacco smoking is associated with lung cancer and other respiratory diseases. However, little is known about the global molecular changes that precede the appearance of clinically detectable symptoms. In this study, the effects of mainstream tobacco smoke (MTS) on global transcription in the mouse lung were investigated.

Methods

Male C57B1/CBA mice were exposed to MTS from two cigarettes daily, 5 days/week for 6 or 12 weeks. Mice were sacrificed immediately, or 6 weeks following the last cigarette. High density DNA microarrays were used to characterize global gene expression changes in whole lung. Microarray results were validated by Quantitative real-time RT-PCR. Further analysis of protein synthesis and function was carried out for a select set of genes by ELISA and Western blotting.

Results

Globally, seventy nine genes were significantly differentially expressed following the exposure to MTS. These genes were associated with a number of biological processes including xenobiotic metabolism, redox balance, oxidative stress and inflammation. There was no differential gene expression in mice exposed to smoke and sampled 6 weeks following the last cigarette. Moreover, cluster analysis demonstrated that these samples clustered alongside their respective controls. We observed simultaneous up-regulation of interleukin 6 (IL-6) and its antagonist, suppressor of cytokine signalling (SOCS3) mRNA following 12 weeks of MTS exposure. Analysis by ELISA and Western blotting revealed a concomitant increase in total IL-6 antigen levels and its downstream targets, including phosphorylated signal transducer and activator of transcription 3 (Stat3), basal cell-lymphoma extra large (BCL-XL) and myeloid cell leukemia 1 (MCL-1) protein, in total lung tissue extracts. However, in contrast to gene expression, a subtle decrease in total SOCS3 protein was observed after 12 weeks of MTS exposure.

Conclusion

Global transcriptional analysis identified a set of genes responding to MTS exposure in mouse lung. These genes returned to basal levels following smoking cessation, providing evidence to support the benefits of smoking cessation. Detailed analyses were undertaken for IL-6 and its associated pathways. Our results provide further insight into the role of these pathways in lung injury and inflammation induced by MTS.

Acute effects of cigarette smoke on inflammation and oxidative stress: a review

Compared with the effects of chronic smoke exposure on lung function and airway inflammation, there are few data on the acute effects of smoking. A review of the literature identified 123 studies investigating the acute effects of cigarette smoking on inflammation and oxidative stress in human, animal, and in vitro models. An acute smoking model is a relatively easy and sensitive method of investigating the specific effects of cigarette smoke on oxidative stress and inflammation. Acute smoke exposure can result in tissue damage, as suggested by increased products of lipid peroxidation and degradation products of extracellular matrix proteins. Acute cigarette smoke has a suppressive effect on the number of eosinophils and several inflammatory cytokines, possibly due to the anti-inflammatory effect of carbon monoxide. An acute smoking model can supplement other ways of studying the effects of smoking and is an as yet underinvestigated method for intervention studies in smoking related diseases.