CCN1 Secretion Induced by Cigarette Smoking Extracts Augments IL-8 Release from Bronchial Epithelial Cells

Inflammation involves in many cigarette smoke (CS) related diseases including the chronic obstructive pulmonary disease (COPD). Lung epithelial cell released IL-8 plays a crucial role in CS induced lung inflammation. CS and cigarette smoke extracts (CSE) both induce IL-8 secretion and subsequently, IL-8 recruits inflammatory cells into the lung parenchyma. However, the molecular and cellular mechanisms by which CSE triggers IL-8 release remain not completely understood. In this study, we identified a novel extracellular matrix (ECM) molecule, CCN1, which mediated CSE induced IL-8 secretion by lung epithelial cells. We first found that CS and CSE up-regulated CCN1 expression and secretion in lung epithelial cells in vivo and in vitro. CSE up-regulated CCN1 via induction of reactive oxygen spices (ROS) and endoplasmic reticulum (ER) stress. p38 MAPK and JNK activation were also found to mediate the signal pathways in CSE induced CCN1. CCN1 was secreted into ECM via Golgi and membrane channel receptor aquaporin4. After CSE exposure, elevated ECM CCN1 functioned via an autocrine or paracrine manner. Importantly, CCN1 activated Wnt pathway receptor LRP6, subsequently stimulated Wnt pathway component Dvl2 and triggered beta-catenin translocation from cell membrane to cytosol and nucleus. Treatment of Wnt pathway inhibitor suppressed CCN1 induced IL-8 secretion from lung epithelial cells. Taken together, CSE increased CCN1 expression and secretion in lung epithelial cells via induction of ROS and ER stress. Increased ECM CCN1 resulted in augmented IL-8 release through the activation of Wnt pathway.     

Cigarette smoke‐induced HMGB1 translocation and release contribute to migration and NF‐κB activation through inducing autophagy in lung macrophages

High‐mobility group box 1 (HMGB1) shows pro‐inflammatory activity in various inflammatory diseases and has been found up‐regulated in chronic obstructive pulmonary disease (COPD). Lung macrophages play an important role in airway inflammation and lung destruction in COPD, yet whether HMGB1 is involved in cigarette smoke (CS)‐induced lung macrophage dysfunction is unknown. We sought to evaluate the intracellular localization and release of HMGB1 in lung macrophages from COPD patients and CS‐exposed mice, and to investigate the role of HMGB1 in regulating autophagy in CS extract (CSE)‐treated lung macrophages (MH‐S cells). Our results showed that HMGB1 was highly expressed in lung tissues and sera of COPD patients and CS‐exposed mice, along with predominantly cytoplasmic exporting from nuclei in lung macrophages. In vitro experiments revealed that CSE promoted the expression, nucleocytoplasmic translocation and release of HMGB1 partly via the nicotinic acetylcholine receptor (nAChR). Blockade of HMGB1 with chicken anti‐HMGB1 polyclonal antibody (anti‐HMGB1) or glycyrrhizin (Gly) attenuated the increase of LC3B‐II and Beclin1, migration and p65 phosphorylation, suggesting the involvement of HMGB1 in autophagy, migration and NF‐κB activation of lung macrophages. Hydroxychloroquine (CQ), an autophagy inhibitor, enhanced the increase of LC3B‐II but not Beclin1 in CSE or rHMGB1‐treated MH‐S cells, and inhibition of autophagy by CQ and 3‐methyladenine (3‐MA) abrogated the migration and p65 phosphorylation of CSE‐treated cells. These results indicate that CS‐induced HMGB1 translocation and release contribute to migration and NF‐κB activation through inducing autophagy in lung macrophages, providing novel evidence for HMGB1 as a potential target of intervention in COPD.     

Induction of Murine Macrophage M2 Polarization by Cigarette Smoke Extract via the JAK2/STAT3 Pathway

Cigarette smoking is a major pathogenic factor in lung cancer. Macrophages play an important role in host defense and adaptive immunity. These cells display diverse phenotypes for performing different functions. M2 type macrophages usually exhibit immunosuppressive and tumor-promoting characteristics. Although macrophage polarization toward the M2 phenotype has been observed in the lungs of cigarette smokers, the molecular basis of the process remains unclear. In this study, we evaluated the possible mechanisms for the polarization of mouse macrophages that are induced by cigarette smoking (CS) or cigarette smoke extract (CSE). The results showed that exposure to CSE suppressed the production of reactive oxygen species (ROS) and nitric oxide (NO) and down-regulated the phagocytic ability of Ana-1 cells. The CD163 expressions on the surface of macrophages from different sources were significantly increased in in vivo and in vitro studies. The M1 macrophage cytokines TNF-α, IL-12p40 and enzyme iNOS decreased in the culture supernatant, and their mRNA levels decreased depending on the time and concentration of CSE. In contrast, the M2 phenotype macrophage cytokines IL-10, IL-6, TGF-β1 and TGF-β2 were up-regulated. Moreover, phosphorylation of JAK2 and STAT3 was observed after the Ana-1 cells were treated with CSE. In addition, pretreating the Ana-1 cells with the STAT3 phosphorylation inhibitor WP1066 inhibited the CSE-induced CD163 expression, increased the mRNA level of IL-10 and significantly decreased the mRNA level of IL-12. In conclusion, we demonstrated that the M2 polarization of macrophages induced by CS could be mediated through JAK2/STAT3 pathway activation.     

Cortisol modulates the induction of inflammatory gene expression in a rainbow trout macrophage cell line

Glucocorticoid actions on the immune system are diverse and cell type dependent, and little is known about cell type-specific interactions and cross-talk between hormones and cytokines. In this study we have analyzed the gene expression patterns of the rainbow trout macrophage cell line RTS-11 by quantitative PCR, after exposure to combinations of cortisol plus a pro-inflammatory cytokine (e.g. recombinant trout IL-1β, IFN-γ), type I IFN or a PAMP (LPS or poly I:C). Several key genes of the inflammatory process were targetted to assess whether any modulation of their expression occurred due to the addition of cortisol to this cell line. Incubation of macrophages for 3 or 6 h with a physiological concentration of cortisol caused a decrease in expression of IL-6 and IL-8, but no significant changes were observed for the other genes examined. Co-stimulation of cortisol with the inflammatory agents resulted in a general suppression of genes related to the inflammatory response. Cortisol inhibited the up-regulation of IL-8 by all the stimulants after 3 h of co-incubation. Suppression of the up-regulation of IL-6 by rIL-1β, rIFN-γ and poly I:C, of γIP by rIFN-γ or poly I:C, and of Cox-2 by rIL-1β was seen after 6 h. In contrast, cortisol in combination with the pro-inflammatory agents has a synergistic effect on IL-10 expression, an anti-inflammatory molecule, suggesting that the activation of certain macrophage functions that lead to the resolution of inflammation occurs in fish macrophages in response to cortisol treatment.     

The effect of MCP-1 depletion on chemokine and chemokine-related gene expression: evidence for a complex network in acute inflammation

The expression of chemokines has been suggested to involve an interdependent network, with the absence of a single chemokine affecting the expression of multiple other chemokines. Monocyte chemoattractant protein (MCP-1), a member of C-C chemokine superfamily, plays a critical role in the recruitment and activation of leukocytes during acute inflammation. To examine the effect of the loss of MCP-1 on expression of the chemokine network, we compared the mRNA expression profiles of MCP-1(-/-) and wild type mice during the acute inflammatory phase of excisional wounds. Utilizing a mouse cDNA array containing 514 chemokine and chemokine related genes, the loss of MCP-1 was observed to cause a significant upregulation of nine genes (Decorin, Persephin, IL-1beta, MIP-2, MSP, IL1ra, CCR5, CCR3, IL-11) and significant downregulation of two genes (CCR4 and CD3Z) in acute wounds. The array data was confirmed by semi-quantitative RT-PCR. The effect of MCP-1 deletion on chemokine expression was further examined in isolated macrophages. Compared to wild type, LPS-stimulated peritoneal macrophages from MCP-1(-/-) mice showed a significant increase in the expression of RANTES, MIP-1beta, MIP-1alpha and MIP-2 mRNA. The data suggest that loss of a single chemokine perturbs the chemokine network not only in the setting of acute inflammation but even in an isolated inflammatory cell, the macrophage.     

Induction of the chemokine beta peptides, MIP-1 alpha and MIP-1 beta, by lipopolysaccharide is differentially regulated by immunomodulatory cytokines gamma-IFN, IL-10, IL-4, and TGF-beta.

The macrophage occupies a central role in the host response to invasion, exerting its control over the developing inflammatory response largely through the elaboration of an assortment of endogenous mediators including many cytokines. The beta chemokine peptides, macrophage inflammatory protein [MIP]-1 alpha and MIP-1 beta, are two such effectors markedly up-regulated in macrophages following exposure to bacterial lipopolysaccharide (LPS). These highly homologous peptides, like the other members of the beta chemokine family, exhibit diverse but partially overlapping biological activity profiles, suggesting that the cellular participants and intensity of an inflammatory response may in part be regulated by selective expression of these chemokines. Studies reported here demonstrate that, in contrast to the "balanced" MIP-1 alpha/MIP-1 beta chemokine responses of LPS-stimulated macrophage cultures in vitro, circulating levels of MIP-1 beta are significantly higher than those of MIP-1 alpha following LPS administration in vivo. Further studies have revealed that several immunomodulatory cytokines known to be up-regulated in vivo as a consequence of exposure to an invasive stimulus (gamma-IFN, IL-10, IL-4, and transforming growth factor [TGF]-beta) down-regulated the LPS-induced release of MIP-1 alpha by macrophages in vitro, but spared the MIP-1 beta response. This altered pattern of secretion may explain, at least in part, the high circulating levels of MIP-1 beta relative to MIP-1 alpha observed in vivo in response to LPS challenge.     

The role of the liver X receptor in chronic obstructive pulmonary disease

Background

There is a need for novel anti-inflammatory therapies to treat COPD. The liver X receptor (LXR) is a nuclear hormone receptor with anti-inflammatory properties.

Methods

We investigated LXR gene and protein expression levels in alveolar macrophages and whole lung tissue from COPD patients and controls, the effect of LXR activation on the suppression of inflammatory mediators from LPS stimulated COPD alveolar macrophages, and the effect of LXR activation on the induction of genes associated with alternative macrophage polarisation.

Results

The levels of LXR mRNA were significantly increased in whole lung tissue extracts in COPD patients and smokers compared to non-smokers. The expression of LXR protein was significantly increased in small airway epithelium and alveolar epithelium in COPD patients compared to controls. No differences in LXR mRNA and protein levels were observed in alveolar macrophages between patient groups. The LXR agonist GW3965 significantly induced the expression of the LXR dependent genes ABCA1 and ABCG1 in alveolar macrophage cultures. In LPS stimulated alveolar macrophages, GW3965 suppressed the production of CXCL10 and CCL5, whilst stimulating IL-10 production.

Conclusions

GW3965 did not significantly suppress the production of TNFα, IL-1β, or CXCL8. Our major finding is that LXR activation has anti-inflammatory effects on CXC10, CCL5 and IL-10 production from alveolar macrophages.     

Role for TAK1 in cigarette smoke-induced proinflammatory signaling and IL-8 release by human airway smooth muscle cells

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease, characterized by a progressive decline in lung function. Airway smooth muscle (ASM) mass may be increased in COPD, contributing to airflow limitation and proinflammatory cytokine production. Cigarette smoke (CS), the major risk factor of COPD, causes ASM cell proliferation, as well as interleukin-8 (IL-8)-induced neutrophilia. In various cell types, transforming growth factor-β-activated kinase 1 (TAK1) plays a crucial role in MAP kinase and NF-κB activation, as well as IL-8 release induced by IL-1β, TNF-α, and lipopolysaccharide. The role of TAK1 in CS-induced IL-8 release is not known. The aim of this study was to investigate the role of TAK1 in CS-induced NF-κB and MAP kinase signaling and IL-8 release by human ASM cells. Stimulation of these cells with CS extract (CSE) increased IL-8 release and ERK-1/2 phosphorylation, as well as Iκ-Bα degradation and p65 NF-κB subunit phosphorylation. CSE-induced ERK-1/2 phosphorylation and Iκ-Bα degradation were both inhibited by pretreatment with the specific TAK1 inhibitor LL-Z-1640-2 (5Z-7-oxozeaenol; 100 nM). Similarly, expression of dominant-negative TAK1 inhibited CSE-induced ERK-1/2 phosphorylation. In addition, inhibitors of TAK1 and the NF-κB (SC-514; 50 μM) and ERK-1/2 (U-0126; 3 μM) signaling inhibited the CSE-induced IL-8 release by ASM cells. These data indicate that TAK1 plays a major role in CSE-induced ERK-1/2 and NF-κB signaling and in IL-8 release by human ASM cells. Furthermore, they identify TAK1 as a novel target for the inhibition of CS-induced inflammatory responses involved in the development and progression of COPD.     

IL-17A and Serum Amyloid A Are Elevated in a Cigarette Smoke Cessation Model Associated with the Persistence of Pigmented Macrophages,Neutrophils and Activated NK Cells

While global success in cessation advocacy has seen smoking rates fall in many developed countries, persistent lung inflammation in ex-smokers is an increasingly important clinical problem whose mechanistic basis remains poorly understood. In this study, candidate effector mechanisms were assessed in mice exposed to cigarette smoke (CS) for 4 months following cessation from long term CS exposure. BALF neutrophils, CD4⁺ and CD8⁺ T cells and lung innate NK cells remained significantly elevated following smoking cessation. Analysis of neutrophil mobilization markers showed a transition from acute mediators (MIP-2α, KC and G-CSF) to sustained drivers of neutrophil and macrophage recruitment and activation (IL-17A and Serum Amyoid A (SAA)). Follicle-like lymphoid aggregates formed with CS exposure and persisted with cessation, where they were in close anatomical proximity to pigmented macrophages, whose number actually increased 3-fold following CS cessation. This was associated with the elastolytic protease, MMP-12 (macrophage metallo-elastase) which remained significantly elevated post-cessation. Both GM-CSF and CSF-1 were significantly increased in the CS cessation group relative to the control group. In conclusion, we show that smoking cessation mediates a transition to accumulation of pigmented macrophages, which may contribute to the expanded macrophage population observed in COPD. These macrophages together with IL-17A, SAA and innate NK cells are identified here as candidate persistence determinants and, we suggest, may represent specific targets for therapies directed towards the amelioration of chronic airway inflammation.     

Cigarette smoke induces IL-8, but inhibits eotaxin and RANTES release from airway smooth muscle

Background

Cigarette smoke is the leading risk factor for the development of chronic obstructive pulmonary disease (COPD) an inflammatory condition characterised by neutrophilic inflammation and release of proinflammatory mediators such as interleukin-8 (IL-8). Human airway smooth muscle cells (HASMC) are a source of proinflammatory cytokines and chemokines. We investigated whether cigarette smoke could directly induce the release of chemokines from HASMC.

Methods

HASMC in primary culture were exposed to cigarette smoke extract (CSE) with or without TNFα. Chemokines were measured by enzyme-linked immunosorbent assay (ELISA) and gene expression by real time polymerase chain reaction (PCR). Data were analysed using one-way analysis of variance (ANOVA) followed by Bonferroni''s t test

Results

CSE (5, 10 and 15%) induced IL-8 release and expression without effect on eotaxin or RANTES release. At 20%, there was less IL-8 release. TNFα enhanced CSE-induced IL-8 release and expression. However, CSE (5–30%) inhibited TNFα-induced eotaxin and RANTES production. The effects of CSE on IL-8 release were inhibited by glutathione (GSH) and associated with the induction of the oxidant sensing protein, heme oxygenase-1.

Conclusion

Cigarette smoke may directly cause the release of IL-8 from HASMC, an effect enhanced by TNF-α which is overexpressed in COPD. Inhibition of eotaxin and RANTES by cigarette smoke is consistent with the predominant neutrophilic but not eosinophilic inflammation found in COPD.     

Anti-inflammatory role of the cAMP effectors Epac and PKA: implications in chronic obstructive pulmonary disease

Cigarette smoke-induced release of pro-inflammatory cytokines including interleukin-8 (IL-8) from inflammatory as well as structural cells in the airways, including airway smooth muscle (ASM) cells, may contribute to the development of chronic obstructive pulmonary disease (COPD). Despite the wide use of pharmacological treatment aimed at increasing intracellular levels of the endogenous suppressor cyclic AMP (cAMP), little is known about its exact mechanism of action. We report here that next to the β(2)-agonist fenoterol, direct and specific activation of either exchange protein directly activated by cAMP (Epac) or protein kinase A (PKA) reduced cigarette smoke extract (CSE)-induced IL-8 mRNA expression and protein release by human ASM cells. CSE-induced IκBα-degradation and p65 nuclear translocation, processes that were primarily reversed by Epac activation. Further, CSE increased extracellular signal-regulated kinase (ERK) phosphorylation, which was selectively reduced by PKA activation. CSE decreased Epac1 expression, but did not affect Epac2 and PKA expression. Importantly, Epac1 expression was also reduced in lung tissue from COPD patients. In conclusion, Epac and PKA decrease CSE-induced IL-8 release by human ASM cells via inhibition of NF-κB and ERK, respectively, pointing at these cAMP effectors as potential targets for anti-inflammatory therapy in COPD. However, cigarette smoke exposure may reduce anti-inflammatory effects of cAMP elevating agents via down-regulation of Epac1.     

Increased interleukin (IL)-8 and decreased IL-17 production in chronic obstructive pulmonary disease (COPD) provoked by cigarette smoke

Recently, involvement of IL-17 in development of COPD has been noticed. Unlike IL-8, the role of IL-17 in COPD remains controversial. In order to further understand mechanisms in cigarette smoke (CS) induced COPD, we investigated IL-17 and IL-8 levels in different stages of COPD patients, and time courses of IL-17 and IL-8 release in CS induced COPD rats. A total of 73 elderly patients with COPD and 31 healthy volunteers were recruited in the study. IL-17 and IL-8 levels in the sputum and plasma were measured, and number of differential cells was counted. A newly developed CS induced rat COPD model was employed to study time courses of IL-17 and IL-8 release and nucleated cell accumulation. The results showed that IL-8 levels in the sputum of severe COPD patients were elevated by 16.5-fold, but IL-17 levels were reduced by 4.8-fold. While IL-8 correlated with neutrophils, IL-17 correlated with monocytes and lymphocytes. Similarly, level of IL-8 was increased, but IL-17 was decreased in the bronchoalveolar lavage fluid (BALF) of CS rats. Time course study showed that increased IL-8 production in the BALF initiated at 6 weeks, but decreased IL-17 production started at 10 weeks following CS exposure. In conclusion, increased IL-8 level in COPD patients appears mainly secreted from neutrophils and macrophages, whereas decreased IL-17 level seems resulted from reduced number of monocytes or damaged epithelial cells. Increased IL-8 (a proinflammatory cytokine) secretion and decreased IL-17 (a protective cytokine of airways) release can both contribute to development of COPD.     

Regulation of macrophage chemokine expression by lipopolysaccharide in vitro and in vivo.

The host response to Gram-negative LPS is characterized by an influx of inflammatory cells into host tissues, which is mediated, in part, by localized production of chemokines. The expression and function of chemokines in vivo appears to be highly selective, though the molecular mechanisms responsible are not well understood. All CXC (IFN-gamma-inducible protein (IP-10), macrophage inflammatory protein (MIP)-2, and KC) and CC (JE/monocyte chemoattractant protein (MCP)-1, MCP-5, MIP-1alpha, MIP-1beta, and RANTES) chemokine genes evaluated were sensitive to stimulation by LPS in vitro and in vivo. While IL-10 suppressed the expression of all LPS-induced chemokine genes evaluated in vitro, treatment with IFN-gamma selectively induced IP-10 and MCP-5 mRNAs, but inhibited LPS-induced MIP-2, KC, JE/MCP-1, MIP-1alpha, and MIP-1beta mRNA and/or protein. Like the response to IFN-gamma, LPS-mediated induction of IP-10 and MCP-5 was Stat1 dependent. Interestingly, only the IFN-gamma-mediated suppression of LPS-induced KC gene expression was IFN regulatory factor-2 dependent. Treatment of mice with LPS in vivo also induced high levels of chemokine mRNA in the liver and lung, with a concomitant increase in circulating protein. Hepatic expression of MIP-1alpha, MIP-1beta, RANTES, and MCP-5 mRNAs were dramatically reduced in Kupffer cell-depleted mice, while IP-10, KC, MIP-2, and MCP-1 were unaffected or enhanced. These findings indicate that selective regulation of chemokine expression in vivo may result from differential response of macrophages to pro- and antiinflammatory stimuli and to cell type-specific patterns of stimulus sensitivity. Moreover, the data suggest that individual chemokine genes are differentially regulated in response to LPS, suggesting unique roles during the sepsis cascade.     

Fish-oil-derived n-3 polyunsaturated fatty acids reduce NLRP3 inflammasome activity and obesity-related inflammatory cross-talk between adipocytes and CD11b+ macrophages

Adipocyte–macrophage cross-talk propagates immune responses in obese adipose tissue (AT). Long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) mitigate inflammation, partly through up-regulation of adiponectin; however, specific mechanisms are unclear. We determined if adipocyte–macrophage cross-talk could be mitigated by dietary LC n-3 PUFA and if this was dependent on adiponectin-mediated signaling. We utilized an in vitro co-culture model mimicking the ratio of adipocytes:macrophages in obese AT, whereby 3T3-L1 adipocytes were co-cultured with splenic CD11b⁺ macrophages from C57BL/6 mice fed high-fat control (HF-CON; 34% w/w fat) or fish oil diets (HF-FO; 34% w/w fat containing 7.6% w/w FO), as well as mice fed low-fat control (LF-CON; 10% w/w fat) or FO diets (LF-FO; 10% w/w fat containing 3% w/w FO). Co-culture conditions tested effects of soluble mediator-driven mechanisms (trans-well system), cell contact and low-dose lipopolysaccharide (LPS) mimicking acute or chronic inflammatory conditions. HF-FO macrophages from acute LPS-stimulated trans-well co-cultures had decreased mRNA expression of Casp1, Il1β and Il18, as well as cellular caspase-1 activity compared to HF-CON macrophages (P ≤ .05). Moreover, adipocytes from acute LPS-stimulated HF-FO co-cultures had decreased caspase-1 activity and decreased IL-1β/IL-18 levels following chronic LPS pretreatment compared to HF-CON co-cultures (P ≤ .05). Additionally, in contact co-cultures with adiponectin-neutralizing antibody, the FO-mediated modulation of NFκB activity and decrease in phosphorylated p65 NFκB, expression of NLRP3 inflammasome genes, M1 macrophage marker genes and inflammatory cytokine/chemokine secretion were controlled partly through adiponectin, while cellular caspase-1 activity and IL-1β/1L-18 levels were decreased independently of adiponectin (P ≤ .05). LC n-3 PUFA may decrease the intensity of adipocyte–macrophage cross-talk to mitigate obesity-associated pathologies.     

Modulation of Endothelial Inflammation by Low and High Magnitude Cyclic Stretch

Excessive mechanical ventilation exerts pathologic mechanical strain on lung vascular endothelium and promotes endothelial cell (EC) inflammatory activation; however, the specific mechanisms underlying EC inflammatory response caused by mechanical ventilation related cyclic stretch (CS) remain unclear. This study investigated the effects of chronic exposure to CS at physiologic (5%) and pathologic (18%) magnitude on pulmonary EC inflammatory status in control conditions and bacterial lipopolysacharide (LPS)-stimulated conditions. EC exposure to high or low CS magnitudes for 28–72 hrs had distinct effects on EC inflammatory activation. 18% CS increased surface expression of endothelial adhesion molecule ICAM1 and release of its soluble form (sICAM1) and inflammatory cytokine IL-8 by CS-stimulated pulmonary endothelial cells (EC). EC inflammatory activation was not observed in EC exposed to 5% CS. Chronic exposure to 18% CS, but not to 5% CS, augmented ICAM1 and IL-8 production and EC monolayer barrier disruption induced by LPS. 18% CS, but not 5% CS, stimulated expression of RhoA GTPase-specific guanine nucleotide exchange factor GEF-H1. GEF-H1 knockdown using gene-specific siRNA abolished 18% CS-induced ICAM1 expression and sICAM1 and IL-8 release by EC. GEF-H1 knockdown also prevented disruption of EC monolayer integrity and attenuated sICAM1 and IL-8 release in the two-hit model of EC barrier dysfunction caused by combined stimulation with 18% CS and LPS. These data demonstrate that exacerbation of inflammatory response by pulmonary endothelium exposed to excessive mechanical stretch is mediated by CS-induced induction of Rho activating protein GEF-H1.     

Anti-Inflammatory Effects of Lactobacillus Rahmnosus and Bifidobacterium Breve on Cigarette Smoke Activated Human Macrophages

Background

Chronic obstructive pulmonary disease (COPD) is a major global health problem with cigarette smoke (CS) as the main risk factor for its development. Airway inflammation in COPD involves the increased expression of inflammatory mediators such as CXCL-8 and IL-1β which are important mediators for neutrophil recruitment. Macrophages are an important source of these mediators in COPD. Lactobacillus rhamnosus (L. rhamnosus) and Befidobacterium breve (B. breve) attenuate the development of ‘allergic asthma’ in animals but their effects in COPD are unknown.

Objective

To determine the anti-inflammatory effects of L. rhamnosus and B. breve on CS and Toll-like receptor (TLR) activation.

Design

We stimulated the human macrophage cell line THP-1 with CS extract in the presence and absence of L. rhamnosus and B. breve and measured the expression and release of inflammatory mediators by RT-qPCR and ELISA respectively. An activity assay and Western blotting were used to examine NF-κB activation.

Results

Both L. rhamnosus and B. breve were efficiently phagocytized by human macrophages. L. rhamnosus and B. breve significantly suppressed the ability of CS to induce the expression of IL-1β, IL-6, IL-10, IL-23, TNFα, CXCL-8 and HMGB1 release (all p<0.05) in human THP-1 macrophages. Similar suppression of TLR4- and TLR9-induced CXCL8 expression was also observed (p<0.05). The effect of L. rhamnosus and B. breve on inflammatory mediator release was associated with the suppression of CS-induced NF-κB activation (p<0.05).

Conclusions

This data indicate that these probiotics may be useful anti-inflammatory agents in CS-associated disease such as COPD.     

Pre-Exposure of Mycobacterium tuberculosis-Infected Macrophages to Crystalline Silica Impairs Control of Bacterial Growth by Deregulating the Balance between Apoptosis and Necrosis

Inhalation of crystalline silica (CS) particles increases the risk of pulmonary tuberculosis; however, the precise mechanism through which CS exposure facilitates Mycobacterium tuberculosis (Mtb) infection is unclear. We speculate that macrophage exposure to CS deregulates the cell death pathways that could explain, at least in part, the association observed between exposure to CS and pulmonary tuberculosis. We therefore established an in vitro model in which macrophages were exposed to CS and then infected with Mtb. Expression of surface markers was analyzed by flow cytometry, JNK1/2, ASK1, caspase 9, P-p38, Bcl-2 and Mcl-1 were analyzed by Western blot, and cytokines by ELISA. Our results show that exposure to CS limits macrophage ability to control Mtb growth. Moreover, this exposure reduced the expression of TLR2, Bcl-2 and Mcl-1, but increased that of JNK1 and ASK1 molecules in the macrophages. Finally, when the pre-exposed macrophages were infected with Mtb, the concentrations of TNFα, IL-1β and caspase-9 expression increased. This pro-inflammatory profile of the macrophage unbalanced the apoptosis/necrosis pathway. Taken together, these data suggest that macrophages exposed to CS are sensitized to cell death by MAPK kinase-dependent signaling pathway. Secretion of TNF-α and IL-1β by Mtb-infected macrophages promotes necrosis, and this deregulation of cell death pathways may favor the release of viable bacilli, thus leading to the progression of tuberculosis.