Glucocorticoid sensitivity of lipopolysaccharide-stimulated chronic obstructive pulmonary disease alveolar macrophages

How inhaled corticosteroids target inflammation in COPD

Inhaled corticosteroids (ICS) are the most commonly used anti-inflammatory drugs for the treatment of COPD. COPD has been previously described as a "corticosteroid-resistant" condition, but current clinical trial evidence shows that selected COPD patients, namely those with increased exacerbation risk plus higher blood eosinophil count (BEC), can benefit from ICS treatment. This review describes the components of inflammation modulated by ICS in COPD and the reasons for the variation in response to ICS between individuals. There are corticosteroid-insensitive inflammatory pathways in COPD, such as bacteria-induced macrophage interleukin-8 production and resultant neutrophil recruitment, but also corticosteroid-sensitive pathways including the reduction of type 2 markers and mast cell numbers. The review also describes the mechanisms whereby ICS can skew the lung microbiome, with reduced diversity and increased relative abundance, towards an excess of proteobacteria. BEC is a biomarker used to enable the selective use of ICS in COPD, but the clinical outcome in an individual is decided by a complex interacting network involving the microbiome and airway inflammation.

Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome

STUDY OBJECTIVES

The coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in a single individual, also known as overlap syndrome (OVS), is associated with higher cardiovascular risk and mortality than either OSA or COPD alone. However, the underlying mechanisms remain unclear. We hypothesized that patients with OVS have elevated systemic inflammatory biomarkers relative to patients with either disease alone, which could explain greater cardiovascular risk observed in OVS.

METHODS

We included 255 participants in the study, 55 with COPD alone, 100 with OSA alone, 50 with OVS, and 50 healthy controls. All participants underwent a home sleep study, spirometry, and a blood draw for high-sensitivity C-reactive protein and total blood count analysis. In a randomly selected subset of 186 participants, inflammatory protein profiling was performed using Bio-Rad Bio-Plex Pro Human Cytokine 27-Plex Assays. Biomarker level differences across groups were identified using a mixed linear model.

RESULTS

Levels of interleukin 6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), and granulocyte colony stimulating factor (G-CSF) were higher in participants with OVS and COPD compared with healthy controls and participants with OSA. Furthermore, participants with OVS had higher circulating levels of leukocytes and neutrophils than those with COPD, OSA, and controls.

CONCLUSIONS

COPD and OVS are associated with higher systemic inflammation relative to OSA and healthy controls. This work proposes the potential utilization of interleukin 6, granulocyte colony stimulating factor, and high-sensitivity C-reactive protein as screening biomarkers for COPD in patients with OSA. Inflammatory pathways may not fully explain the higher cardiovascular risk observed in OVS, indicating the need for further investigation.

CITATION

Sanchez-Azofra A, Gu W, Masso-Silva JA, et al. Inflammation biomarkers in OSA, chronic obstructive pulmonary disease, and chronic obstructive pulmonary disease/OSA overlap syndrome. J Clin Sleep Med. 2023;19(8):1447-1456.

Epimedin C protects dexamethasone-induced osteoblasts through NRF1/RhoA pathway

Osteoporosis (OP) is a metabolic bone disease that leads to decrease of bone strength and increase bone brittle and fracture. Dexamethasone (DXMS) usage is a common risk factor of OP. In present study, we found that the Epimedin C protect the DXMS-induced OP, Ras Homolog Family Member A transforming protein (RhoA) was increased in osteoblasts (OBs) and OP models. We further revealed that Nrf1 is a transcription factor that responds to Epimedin C and DXMS in modulating RhoA promoter. The results collectively demonstrate that Epimedin C functions as a positive modifier of RhoA via alteration of Nrf1 transcriptional activity on RhoA promoter, thereby, protecting OBs against OP. Our work is the first study identifying the Epimedin C function in balancing the OBs in OP model via Nrf1-RhoA.

Inflammatory Serum Biomarker Pattern in Emphysema and Chronic Bronchitis Phenotypes of Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Background

COPD exacerbation is characterized by both airway and systemic inflammation. The present study aimed to investigate the relationship between serum levels of some inflammatory biomarkers and the phenotypes of COPD exacerbation.

Materials and Methods

This study includes known COPD patients, presenting to a hospital with acute exacerbation of COPD. Serum levels of CRP, ESR, CBC, TNF-α, IL-8, and IL-6 were measured at the time of admission. According to the previously done HRCT, the patients were divided into two groups including emphysema and chronic bronchitis. Levels of serum biomarkers were compared in the two groups. The relationships between biomarkers and duration of hospitalization were assessed too.

Results

Comparison of quantitative CRP levels, WBC, and platelet counts did not show a statistically significant difference between emphysema and chronic bronchitis but it was significantly higher than control subjects. Although not statistically significant, ESR level was higher in emphysema. TNF-alpha was 6.0±1.5 ng / ml and 1.5 ng / ml in the emphysema and chronic bronchitis groups, respectively. TNF-α had no significant difference compared to the groups. Although higher than the control group, IL-6 and IL-8 did not show significant differences between emphysema and chronic bronchitis. The two groups did not statistically differ in terms of hospital stay but patients with higher serum TNF-α tended to have longer hospitalization and ICU admission.

Conclusion

The present study showed predictably higher inflammatory biomarkers in COPD exacerbation but no significant difference between the two phenotypes of COPD and these two entities could not be discriminated based on inflammatory bio-factors.

OR2AT4 and OR1A2 counterregulate molecular pathophysiological processes of steroid-resistant inflammatory lung diseases in human alveolar macrophages

BACKGROUND

Therapeutic options for steroid-resistant non-type 2 inflammation in obstructive lung diseases are lacking. Alveolar macrophages are central in the progression of these diseases by releasing proinflammatory cytokines, making them promising targets for new therapeutic approaches. Extra nasal expressed olfactory receptors (ORs) mediate various cellular processes, but clinical data are lacking. This work investigates whether ORs in human primary alveolar macrophages could impact pathophysiological processes and could be considered as therapeutic targets.

METHODS

Human primary alveolar macrophages were isolated from bronchoalveolar lavages of 50 patients with pulmonary diseases. The expression of ORs was validated using RT-PCR, immunocytochemical staining, and Western blot. Changes in intracellular calcium levels were analyzed in real-time by calcium imaging. A luminescent assay was used to measure the cAMP concentration after OR stimulation. Cytokine secretion was measured in cell supernatants 24 h after stimulation by ELISA. Phagocytic ability was measured by the uptake of fluorescent-labeled beads by flow cytometry.

RESULTS

We demonstrated the expression of functional OR2AT4 and OR1A2 on mRNA and protein levels. Both ORs were primarily located in the plasma membrane. Stimulation with Sandalore, the ligand of OR2AT4, and Citronellal, the ligand of OR1A2, triggered a transient increase of intracellular calcium and cAMP. In the case of Sandalore, this calcium increase was based on a cAMP-dependent signaling pathway. Stimulation of alveolar macrophages with Sandalore and Citronellal reduced phagocytic capacity and release of proinflammatory cytokines.

CONCLUSION

These are the first indications for utilizing olfactory receptors as therapeutic target molecules in treating steroid-resistant lung diseases with non-type 2 inflammation.

Ruxolitinib inhibits cytokine production by human lung macrophages without impairing phagocytic ability

Background: The Janus kinase (JAK) 1/2 inhibitor ruxolitinib has been approved in an indication of myelofibrosis and is a candidate for the treatment of a number of inflammatory or autoimmune diseases. We assessed the effects of ruxolitinib on lipopolysaccharide (LPS)- and poly (I:C)-induced cytokine production by human lung macrophages (LMs) and on the LMs’ phagocytic activity.

Methods: Human LMs were isolated from patients operated on for lung carcinoma. The LMs were cultured with ruxolitinib (0.5 × 10−7 M to 10–5 M) or budesonide (10–11 to 10–8 M) and then stimulated with LPS (10 ng·ml−1) or poly (I:C) (10 μg·ml−1) for 24 h. Cytokines released by the LMs into the supernatants were measured using ELISAs. The phagocytosis of labelled bioparticles was assessed using flow cytometry.

Results: Ruxolitinib inhibited both the LPS- and poly (I:C)-stimulated production of tumor necrosis factor alpha, interleukin (IL)-6, IL-10, chemokines CCL2, and CXCL10 in a concentration-dependent manner. Ruxolitinib also inhibited the poly (I:C)- induced (but not the LPS-induced) production of IL-1ß. Budesonide inhibited cytokine production more strongly than ruxolitinib but failed to mitigate the production of CXCL10. The LMs’ phagocytic activity was not impaired by the highest tested concentration (10–5 M) of ruxolitinib.

Conclusion: Clinically relevant concentrations of ruxolitinib inhibited the LPS- and poly (I:C)-stimulated production of cytokines by human LMs but did not impair their phagocytic activity. Overall, ruxolitinib’s anti-inflammatory activities are less intense than (but somewhat different from) those of budesonide—particularly with regard to the production of the corticosteroid-resistant chemokine CXCL-10. Our results indicate that treatment with a JAK inhibitor might be a valuable anti-inflammatory strategy in chronic obstructive pulmonary disease, Th1-high asthma, and both viral and non-viral acute respiratory distress syndromes (including coronavirus disease 2019).

Red Blood Cell-Derived Iron Alters Macrophage Function in COPD

Lung macrophage iron levels are increased in COPD patients. Lung macrophage iron levels are thought to be increased by cigarette smoke, but the role of red blood cells (RBCs) as a source of iron has not been investigated. We investigate RBCs as a potential source of alveolar iron in COPD, and determine the effect of RBC-derived iron on macrophage function. We used lung tissue sections to assess RBC coverage of the alveolar space, iron and ferritin levels in 11 non-smokers (NS), 15 smokers (S) and 32 COPD patients. Lung macrophages were isolated from lung resections (n = 68) and treated with hemin or ferric ammonium citrate (50, 100 or 200 μM). Lung macrophage phenotype marker gene expression was measured by qPCR. The phagocytosis of Non-typeable Haemophilus influenzae (NTHi) was measured by flow cytometry. Cytokine production in response to NTHi in iron-treated macrophages was measured by ELISA. Lung macrophage iron levels were significantly correlated with RBC coverage of the alveolar space (r = 0.31, p = 0.02). Furthermore, RBC coverage and lung macrophage iron were significantly increased in COPD patients and correlated with airflow obstruction. Hemin treatment downregulated CD36, CD163, HLA-DR, CD38, TLR4, CD14 and MARCO gene expression. Hemin-treated macrophages also impaired production of pro-inflammatory cytokines in response to NTHi exposure, and decreased phagocytosis of NTHi (200 μM: 35% decrease; p = 0.03). RBCs are a plausible source of pulmonary iron overload in COPD. RBC-derived iron dysregulates macrophage phenotype and function.

Metabolic reprograming of LPS-stimulated human lung macrophages involves tryptophan metabolism and the aspartate-arginosuccinate shunt

Lung macrophages (LM) are in the first line of defense against inhaled pathogens and can undergo phenotypic polarization to the proinflammatory M1 after stimulation with Toll-like receptor agonists. The objective of the present work was to characterize the metabolic alterations occurring during the experimental M1 LM polarization. Human LM were obtained from resected lungs and cultured for 24 hrs in medium alone or with 10 ng.mL-1 lipopolysaccharide. Cells and culture supernatants were subjected to extraction for metabolomic analysis with high-resolution LC-MS (HILIC and reverse phase -RP- chromatography in both negative and positive ionization modes) and GC-MS. The data were analyzed with R and the Worklow4Metabolomics and MetaboAnalyst online infrastructures. A total of 8,741 and 4,356 features were detected in the intracellular and extracellular content, respectively, after the filtering steps. Pathway analysis showed involvement of arachidonic acid metabolism, tryptophan metabolism and Krebs cycle in the response of LM to LPS, which was confirmed by the specific quantitation of selected compounds. This refined analysis highlighted a regulation of the kynurenin pathway as well as the serotonin biosynthesis pathway, and an involvement of aspartate-arginosuccinate shunt in the malate production. Macrophages M1 polarization is accompanied by changes in the cell metabolome, with the differential expression of metabolites involved in the promotion and regulation of inflammation and antimicrobial activity. The analysis of this macrophage immunometabolome may be of interest for the understanding of the pathophysiology of lung inflammatory disesases.

P38 MAPK and glucocorticoid receptor crosstalk in bronchial epithelial cells

Abstract

p38 MAPK inhibition may have additive and synergistic anti-inflammatory effects when used with corticosteroids. We investigated crosstalk between p38 MAPK inhibitors and corticosteroids in bronchial epithelial cells to investigate synergistic effects on cytokine production and the molecular mechanisms involved. Effects of the p38 MAPK inhibitor BIRB-796 and dexamethasone alone and in combination on LPS, polyI:C or TNFα -induced IL-6, CXCL8 and RANTES were assessed in 16HBEs (human epithelial cell line) and on TNFα-induced IL-6 and CXCL8 in primary human epithelial cells from asthma patients and healthy controls. 16HBEs were used to assess effects of BIRB-796 alone and in combination with dexamethasone on glucocorticoid receptor (GR) activity by reporter gene assay, expression of GR target genes and nuclear localisation using Western blot. The effects of BIRB-796 on TNFα stimulated phosphorylation of p38 MAPK and GR at serine (S) 226 by Western blot. Epithelial levels of phosphorylated p38 MAPK and GR S226 were determined by immunohistochemistry in bronchial biopsies from asthma patients and healthy controls. BIRB-796 in combination with dexamethasone increased inhibition of cytokine production in a synergistic manner. Combination treatment significantly increased GR nuclear localisation compared to dexamethasone alone. BIRB-796 inhibited TNFα-induced p38 MAPK and GR S226 phosphorylation. Phosphorylated GR S226 and p38 MAPK levels were increased in bronchial epithelium of more severe asthma patients. Molecular crosstalk exists between p38 MAPK activation and GR function in human bronchial epithelial cells, which alters GR activity. Combining a p38 MAPK inhibitor and a corticosteroid may demonstrate therapeutic potential in severe asthma.

Key messages

• Combination of corticosteroid and p38 inhibitor in human bronchial epithelial cells

• Combination increased cytokine inhibition synergistically and nuclear GR

• p38 MAPK inhibition reduced TNFα-induced phosphorylation of GR at S226 but not S211

• Phosphorylated GRS226 and p38 is increased in bronchial epithelium in severe asthma

• Combining a p38 inhibitor and a corticosteroid may be effective in asthma treatment

Electronic supplementary material

The online version of this article (10.1007/s00109-020-01873-3) contains supplementary material, which is available to authorized users.

Bitter Taste Receptors (TAS2Rs) in Human Lung Macrophages: Receptor Expression and Inhibitory Effects of TAS2R Agonists

BACKGROUND

Bitter-taste receptors (TAS2Rs) are involved in airway relaxation but are also expressed in human blood leukocytes. We studied TAS2R expression and the effects of TAS2R agonists on the lipopolysaccharide (LPS)-induced cytokine release in human lung macrophages (LMs).

METHODS

Lung macrophages were isolated from patients undergoing surgery for carcinoma. We used RT-qPCR to measure transcripts of 16 TAS2Rs (TAS2Rs 3/4/5/7/8/9/10/14/19/20/31/38/39/43/45 and 46) in unstimulated and LPS-stimulated (10 ng.mL-1) LMs. The macrophages were also incubated with TAS2R agonists for 24 h. Supernatant levels of the cytokines TNF-α, CCL3, CXCL8 and IL-10 were measured using ELISAs.

RESULTS

The transcripts of all 16 TAS2Rs were detected in macrophages. The addition of LPS led to an increase in the expression of most TAS2Rs, which was significant for TAS2R7 and 38. Although the promiscuous TAS2R agonists, quinine and denatonium, inhibited the LPS-induced release of TNF-α, CCL3 and CXCL8, diphenidol was inactive. Partially selective agonists (dapsone, colchicine, strychnine, and chloroquine) and selective agonists [erythromycin (TAS2R10), phenanthroline (TAS2R5), ofloxacin (TAS2R9), and carisoprodol (TAS2R14)] also suppressed the LPS-induced cytokine release. In contrast, two other agonists [sodium cromoglycate (TAS2R20) and saccharin (TAS2R31 and 43)] were inactive. TAS2R agonists suppressed IL-10 production - suggesting that this anti-inflammatory cytokine is not involved in the inhibition of cytokine production.

CONCLUSION

Human LMs expressed TAS2Rs. Experiments with TAS2R agonists' suggested the involvement of TAS2Rs 3, 4, 5, 9, 10, 14, 30, 39 and 40 in the inhibition of cytokine production. TAS2Rs may constitute new drug targets in inflammatory obstructive lung disease.

New therapeutic targets for the prevention of infectious acute exacerbations of COPD: role of epithelial adhesion molecules and inflammatory pathways

Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution.

The Role of Toll-Like Receptors in the Production of Cytokines by Human Lung Macrophages

BACKGROUND

The Toll-like receptor (TLR) family is involved in the recognition of and response to microbial infections. These receptors are expressed in leukocytes. TLR stimulation induces the production of proinflammatory cytokines and chemokines. Given that human lung macrophages (LMs) constitute the first line of defense against inhaled pathogens, the objective of this study was to investigate the expression and function of TLR subtypes in this cell population.

METHODS

Human primary LMs were obtained from patients undergoing surgical resection. The RNA and protein expression levels of TLRs, chemokines, and cytokines were assessed after incubation with subtype-selective agonists.

RESULTS

In human LMs, the TLR expression level varied from one subtype to another. Stimulation with subtype-selective agonists induced an intense, concentration- and time-dependent increase in the production of chemokines and cytokines. TLR4 stimulation induced the strongest effect, whereas TLR9 stimulation induced a much weaker response.

CONCLUSIONS

The stimulation of TLRs in human LMs induces intense cytokine and chemokine production, a characteristic of the proinflammatory M1 macrophage phenotype.

Dexamethasone induces osteoblast apoptosis through ROS-PI3K/AKT/GSK3β signaling pathway

BACKGROUND

Osteoblasts play important roles in the process of osteogenesis and prevention of osteonecrosis. Dexamethasone (Dex), a type of glucocorticoids (GCs), induces apoptosis of osteoblasts and leads to the occurrence of non-traumatic osteonecrosis. This study aimed to explore the effects of phosphatidylinositol 3-kinase/Protein kinase 3 (PI3K/AKT) and glycogen synthase kinase 3β (GSK3β) on Dex-induced osteoblasts apoptosis.

METHODS

Viabilities, proliferation, and apoptosis of primary osteoblasts and pre-osteoblast MC3T3-E1 cells after Dex treatment were detected using cell counting kit-8 (CCK-8) assay, 5-bromo-2'-deoxyuridine (BrdU) incorporation assay, FITC-Annexin V/PI staining and western blotting, respectively. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining was performed to measure the intracellular reactive oxygen species (ROS) levels after Dex treatment. N-acetyl-l-cysteine (NAC) was used as ROS scavenger in this research. The expressions of PI3K/AKT and GSK3β in osteoblasts and MC3T3-E1 cells after Dex treatment were analyzed using western blotting and qRT-PCR, respectively. Then the effects of GSK3β knockdown on Dex-induced apoptosis of osteoblasts were explored. Alkaline phosphatase (ALP) activity assay was used to detect the role of Dex in regulating ALP activity.

RESULTS

Dex remarkably inhibited proliferation and induced apoptosis of osteoblasts and MC3T3-E1 cells. Dex potentially attenuated the osteoblast differentiation. The intracellular ROS levels were significantly increased after Dex treatment. Dex suppressed the activation of PI3K/AKT pathway in osteoblasts and MC3T3-E1 cells by down-regulating the expressions of p-PI3K and p-AKT. The expressions of GSK3β in osteoblasts and MC3T3-E1 cells were obviously up-regulated after Dex treatment. Knockdown of GSK3β alleviated Dex-induced osteoblast and MC3T3-E1 cell apoptosis by decreasing the expressions of Bax, cleaved-caspase 3, cleaved-caspase 9 and increasing the expression of Bcl-2.

CONCLUSION

Our research verified that Dex induced osteoblasts apoptosis by ROS-PI3K/AKT/GSK3β signaling pathway.

Dexamethasone Inhibits Synergistic Induction of PDE4B Expression by Roflumilast and Bacterium NTHi

Phosphodiesterase 4B (PDE4B) plays an important role in inflammation. Recently we have reported that roflumilast as a PDE4-selective inhibitor, synergizes with nontypeable Haemophilus influenzae (NTHi) to up-regulate PDE4B expression in vitro and in vivo. Clinical evidence and our previous results suggest that synergistic induction of PDE4B could be counterproductive for suppressing inflammation or may contribute to tolerance to roflumilast. We thus investigated if dexamethasone inhibits the synergistic induction of PDE4B by roflumilast and NTHi as well as inflammation. Here, dexamethasone markedly suppressed the synergistic induction of PDE4B in human lung epithelial cells and in vivo. We also found that dexamethasone further suppressed NTHi-induced inflammatory response in vitro and in vivo. Moreover, Compound A, as a dissociating non-steroidal glucocorticoid receptor (GR) ligand, inhibited the synergistic induction of PDE4B, thereby suggesting the requirement of dexamethasone-mediated GR activation in the suppression of PDE4B expression. Taken together, our data suggest that dexamethasone may help attenuate inflammation and tolerance through suppressing the PDE4B expression in chronic obstructive pulmonary disease (COPD) patients using roflumilast.

Differential anti-inflammatory effects of budesonide and a p38 MAPK inhibitor AZD7624 on COPD pulmonary cells

Background

The effects of anti-inflammatory drugs in COPD patients may vary between different cell types. The aim of the current study was to assess the anti-inflammatory effects of the corticosteroid budesonide and a p38 MAPK inhibitor (AZD7624) on different cell types obtained from COPD patients and healthy controls.

Methods

Eight healthy smokers, 16 COPD infrequent exacerbators, and 16 frequent COPD exacerbators (≥2 exacerbations in the last year) were recruited for bronchoscopy and blood sampling. The anti-inflammatory effects of budesonide and AZD7624 were assessed on cytokine release from lipopolysaccharide-stimulated alveolar macrophages and peripheral blood mononuclear cells and polyinosinic:polycytidylic acid-stimulated bronchial epithelial cells.

Results

The anti-inflammatory effects of budesonide varied greatly within a patient according to the cell type studied. Bronchial epithelial cells showed the lowest sensitivity to budesonide, while peripheral blood mononuclear cells showed the greatest sensitivity. AZD7624 had a greater effect than budesonide on cytokine production from bronchial epithelial cells. Exacerbation frequency did not influence corticosteroid sensitivity.

Conclusion

We observed variable corticosteroid and p38 MAPK inhibitor anti-inflammatory responses within the same individual depending on the cell type studied. These findings support the use of multiple anti-inflammatory strategies in COPD patients due to differences between cell types.

The effects of repeated Toll-like receptors 2 and 4 stimulation in COPD alveolar macrophages

Background

COPD is a progressive inflammatory airway disease characterized by increased numbers of alveolar macrophages in the lungs. Bacterial colonization of the lungs is a common feature in COPD and can promote inflammation through continual and repeated Toll-like receptor (TLR) stimulation. We have studied the response of COPD alveolar macrophages to repetitive stimulation with TLR2 and TLR4 ligands. We investigated the effect of sequential stimulation with different ligands to determine whether this results in tolerance or amplification of the immune response.

Methods

We stimulated alveolar macrophages from COPD patients (n=9) and smokers (n=8) with the TLR4 agonist lipopolysaccharide (LPS) or the TLR2 agonist Pam3CSK4 for 24 hours before restimulating again for 24 hours. Cytokine protein release and gene expression were investigated.

Results

Repetitive stimulation of COPD and smokers macrophages with LPS for both 24-hour periods caused a reduction in tumor necrosis factor α, CCL5, and IL-10 production compared to cells that were not exposed initially to LPS. IL-6 and CXCL8 production were not significantly altered following repetitive LPS stimulation. The same pattern was observed for repeated stimulation with Pam3CSK4. Using COPD macrophages, LPS followed by Pam3CSK4 stimulation increased the levels of all cytokines compared to media followed by Pam3CSK4.

Conclusion

TLR tolerance in COPD alveolar macrophages occurs after repetitive stimulation with the same TLR ligand, but this only occurs for selected cytokines. CXCL8 production is not reduced after repetitive TLR stimulation with the same ligand; this may be an important mechanism for the increased CXCL8 levels that have been observed in COPD. We showed that TLR4 stimulation followed by TLR2 stimulation does not cause tolerance, but enhances cytokine production. This may be a relevant mechanism by which bacteria cause excessive inflammation in COPD patients.

RV568, a narrow-spectrum kinase inhibitor with p38 MAPK-α and -γ selectivity, suppresses COPD inflammation

Novel anti-inflammatory approaches targeting chronically activated kinase pathways in chronic obstructive pulmonary disease (COPD) are needed. We evaluated RV568, a p38 mitogen-activated protein kinase-α and -γ and SRC family kinase inhibitor, in cellular and in vivo models relevant to COPD and examined its safety and efficacy in COPD patients.The anti-inflammatory activities of RV568 were tested in primary cultured monocytes, macrophages and bronchial epithelial cells and in vivo in lipopolysaccharide and cigarette smoke-exposed murine models. RV568 was evaluated in a 14-day trial in COPD patients.RV568 showed potent anti-inflammatory effects in monocytes and macrophages, which were often greater than those of corticosteroids or the p38 inhibitor Birb796. RV568 combined with corticosteroid had anti-inflammatory effects suggestive of a synergistic interaction in poly I:C-stimulated BEAS-2B cells and in the cigarette smoke model. In COPD patients, inhaled RV568 (50 µg and 100 µg) improved pre-bronchodilator forced expiratory volume in 1 s (69 mL and 48 mL respectively) and significantly reduced sputum malondialdehyde (p<0.05) compared to placebo, although there were no changes in sputum cell counts. Adverse events during RV568 and placebo treatment were similar.RV568 shows potent anti-inflammatory effects on cell and animal models relevant to COPD. RV568 was well-tolerated and demonstrated a modest clinical benefit in a 14-day COPD clinical trial.

LPS regulates the expression of glucocorticoid receptor α and β isoforms and induces a selective glucocorticoid resistance in vitro

Background

This study was aimed to evaluate the effect of LPS in glucocorticoid receptor (GR) isoforms expression on different cell lines and PBMC from healthy donors in vitro and glucocorticoid sensitivity of PBMC in vitro.

Methods

U-2 OS cell lines expressing GR isoforms, different cell lines (CEM, RAJI, K562 and HeLa) or PBMC from healthy donors, were cultured or not with LPS. The expression of GRα and GRβ was evaluated by Western blot. Glucocorticoid sensitivity was evaluated in PBMC treated with LPS, testing genes which are transactivated or transrepressed by glucocorticoid. For transactivated genes (MKP1, FKBP5) PBMC were treated with Dexamethasone 100 nM for 6 h. The mRNA expression was measured by RT-PCR. For transrepressed genes (IL-8, GM-CSF), PBMC were cultured in Dexamethasone 100 nM and LPS 10 μg/ml for 6 h and protein expression was measure by ELISA.

Results

GR isoforms were induced in U-2 OS cells with a greater effect on GRα expression. Both isoforms were also induced in CEM cells with a tendency to a greater effect on GRβ. LPS induced only the expression of GRα in Raji and HeLa cells, and in PBMC, with no effect in K562 cells. LPS induced a loss of glucocorticoid inhibitory effect only on the secretion of GM-CSF.

Conclusion

LPS in vitro differentially modulates the expression of GR isoforms in a cell specific manner. In PBMC from healthy donors LPS induces an approximately two times increase in the expression of GRα and a loss of the glucocorticoid inhibitory effect on the secretion of GM-CSF, without affecting other glucocorticoid responses evaluated.

Electronic supplementary material

The online version of this article (10.1186/s12950-017-0169-0) contains supplementary material, which is available to authorized users.

Characterisation of lung macrophage subpopulations in COPD patients and controls

Lung macrophage subpopulations have been identified based on size. We investigated characteristics of small and large macrophages in the alveolar spaces and lung interstitium of COPD patients and controls. Alveolar and interstitial cells were isolated from lung resection tissue from 88 patients. Macrophage subpopulation cell-surface expression of immunological markers and phagocytic ability were assessed by flow cytometry. Inflammatory related gene expression was measured. Alveolar and interstitial macrophages had subpopulations of small and large macrophages based on size and granularity. Alveolar macrophages had similar numbers of small and large cells; interstitial macrophages were mainly small. Small macrophages expressed significantly higher cell surface HLA-DR, CD14, CD38 and CD36 and lower CD206 compared to large macrophages. Large alveolar macrophages showed lower marker expression in COPD current compared to ex-smokers. Small interstitial macrophages had the highest pro-inflammatory gene expression levels, while large alveolar macrophages had the lowest. Small alveolar macrophages had the highest phagocytic ability. Small alveolar macrophage CD206 expression was lower in COPD patients compared to smokers. COPD lung macrophages include distinct subpopulations; Small interstitial and small alveolar macrophages with more pro-inflammatory and phagocytic function respectively, and large alveolar macrophages with low pro-inflammatory and phagocytic ability.

Mechanisms of corticosteroid insensitivity in COPD alveolar macrophages exposed to NTHi

Background

Non-typeable Haemophilus influenza (NTHi) infection is common in COPD. Corticosteroids can have limited therapeutic effects in COPD patients. NTHi causes corticosteroid insensitive cytokine production from COPD alveolar macrophages. We investigated the mechanisms by which NTHi causes corticosteroid insensitive inflammatory responses, and the effects of NTHi exposure on COPD macrophage polarisation.

Method

Alveolar macrophages from COPD patients and controls were exposed to NTHi in conjunction with the corticosteroid dexamethasone and/or the p38 MAPK inhibitor BIRB-796. Cytokine release, GR phosphorylation and modulation and macrophage phenotype were analysed.

Results

Dexamethasone significantly inhibited NTHi induced TNF-α, IL-6 and IL-10 from COPD macrophages but, CXCL8 was not suppressed.

BIRB-796 combined with dexamethasone caused significantly greater inhibition of all cytokines than either drug alone (p < 0.05 all comparisons). NTHi caused phosphorylation of GR S226 reducing GR nuclear localisation, an effect regulated by p38 MAPK. NTHi altered macrophage polarisation by increasing IL-10 and decreasing CD36, CD206, CD163 and HLA-DR.

Conclusion

NTHi exposure causes p38 MAPK dependent GR phosphorylation associated with decreased GR function in COPD alveolar macrophages. Combining a p38 MAPK inhibitor with corticosteroids can enhance anti-inflammatory effects during NTHi exposure of COPD alveolar macrophages. NTHi causes macrophage polarisation that favours bacterial persistence.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0539-4) contains supplementary material, which is available to authorized users.

Anti-inflammatory potential of PI3Kδ and JAK inhibitors in asthma patients

Background

Phosphatidylinositol 3-kinase delta (PI3Kδ) and Janus-activated kinases (JAK) are both novel anti-inflammatory targets in asthma that affect lymphocyte activation. We have investigated the anti-inflammatory effects of PI3Kδ and JAK inhibition on cytokine release from asthma bronchoalveolar lavage (BAL) cells and T-cell activation, and measured lung PI3Kδ and JAK signalling pathway expression.

Method

Cells isolated from asthma patients and healthy subjects were treated with PI3Kδ or JAK inhibitors, and/or dexamethasone, before T-cell receptor stimulation. Levels of IFNγ, IL-13 and IL-17 were measured by ELISA and flow cytometry was used to assess T-cell activation. PI3Kδ, PI3Kγ, phosphorylated protein kinase B (pAKT) and Signal Transducer and Activator of Transcription (STAT) protein expression were assessed by immunohistochemistry in bronchial biopsy tissue from asthma patients and healthy subjects. PI3Kδ expression in BAL CD3 cells was measured by flow cytometry.

Results

JAK and PI3Kδ inhibitors reduced cytokine levels from both asthma and healthy BAL cells. Combining dexamethasone with either a JAK or PI3Kδ inhibitor showed an additive anti-inflammatory effect. JAK and PI3Kδ inhibitors were shown to have direct effects on T-cell activation. Immunohistochemistry showed increased numbers of PI3Kδ expressing cells in asthma bronchial tissue compared to controls. Asthma CD3 cells in BAL expressed higher levels of PI3Kδ protein compared to healthy cells.

Conclusions

Targeting PI3Kδ or JAK may prove effective in reducing T-cell activation and the resulting cytokine production in asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0436-2) contains supplementary material, which is available to authorized users.

Characterization of TLR-induced inflammatory responses in COPD and control lung tissue explants

PURPOSE

Viruses are a common cause of exacerbations in chronic obstructive pulmonary disease (COPD). They activate toll-like receptors (TLRs) 3, 7, and 8, leading to a pro-inflammatory response. We have characterized the responses of TLR3 and TLR7/8 in lung tissue explants from COPD patients and control smokers.

METHODS

We prepared lung whole tissue explants (WTEs) from patients undergoing surgery for confirmed or suspected lung cancer. In order to mimic the conditions of viral infection, we used poly(I:C) for TLR3 stimulation and R848 for TLR7/8 stimulation. These TLR ligands were used alone and in combination. The effects of tumor necrosis factor α (TNFα) neutralization and dexamethasone on TLR responses were examined. Inflammatory cytokine release was measured by enzyme-linked immunosorbent assay and gene expression by quantitative real-time polymerase chain reaction.

RESULTS

WTEs from COPD patients released higher levels of pro-inflammatory cytokines compared with WTEs from smokers. Activation of multiple TLRs led to a greater than additive release of TNFα and CCL5. TNFα neutralization and dexamethasone treatment decreased cytokine release.

CONCLUSION

This WTE model shows an enhanced response of COPD compared with controls, suggesting an increased response to viral infection. There was amplification of innate immune responses with multiple TLR stimulation.

Differential Effects of p38, MAPK, PI3K or Rho Kinase Inhibitors on Bacterial Phagocytosis and Efferocytosis by Macrophages in COPD

Pulmonary inflammation and bacterial colonization are central to the pathogenesis of chronic obstructive pulmonary disease (COPD). Defects in macrophage phagocytosis of both bacteria and apoptotic cells contribute to the COPD phenotype. Small molecule inhibitors with anti-inflammatory activity against p38 mitogen activated protein kinases (MAPKs), phosphatidyl-inositol-3 kinase (PI3K) and Rho kinase (ROCK) are being investigated as novel therapeutics in COPD. Concerns exist, however, about off-target effects. We investigated the effect of p38 MAPK inhibitors (VX745 and SCIO469), specific inhibitors of PI3K α (NVS-P13K-2), δ (NVS-P13K-3) or γ (NVS-P13K-5) and a ROCK inhibitor PF4950834 on macrophage phagocytosis, early intracellular killing of bacteria and efferocytosis of apoptotic neutrophils. Alveolar macrophages (AM) obtained from broncho-alveolar lavage (BAL) or monocyte-derived macrophages (MDM) from COPD patients (GOLD stage II/III) enrolled from a well characterized clinical cohort (MRC COPD-MAP consortium) or from healthy ex-smoker controls were studied. Both COPD AM and MDM exhibited lower levels of bacterial phagocytosis (using Streptococcus pneumoniae and non-typeable Haemophilus influenzae) and efferocytosis than healthy controls. None of the inhibitors altered bacterial internalization or early intracellular bacterial killing in AM or MDM. Conversely PF4950834, but not other inhibitors, enhanced efferocytosis in COPD AM and MDM. These results suggest none of these inhibitors are likely to exacerbate phagocytosis-related defects in COPD, while confirming ROCK inhibitors can enhance efferocytosis in COPD.

Effects of budesonide on toll-like receptor expression in alveolar macrophages from smokers with and without COPD

INTRODUCTION

Alveolar macrophages (AMs) are equipped with innate immune receptors such as toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4). In primary bronchial epithelial cells, exposure of toll-like receptor (TLR) ligands or tumor necrosis factor-alpha (TNF-α) increased TLR2 mRNA expression and reduced interleukin-8 (IL-8) release when coincubated with glucocorticosteroids. The aim of this study was to compare TLR2 and TLR4 expression levels and the effect of a glucocorticosteroid after stimulation with TLR ligands on AMs from smokers with and without COPD compared with the healthy controls.

SUBJECTS AND METHODS

Bronchoalveolar lavage was performed, and AMs were isolated from smokers with (n=10) and without COPD (n=11) and healthy controls (n=10) and stimulated ex vivo with peptidoglycan (PGN), lipopolysaccharide (LPS), or TNF-α ± budesonide (Bud). Blocking antibodies to TLR2 or TLR4 were added before stimulation with LPS or PGN ± Bud, respectively. The release of proinflammatory cytokine (TNF-α), chemoattractant (CXCL8), and TLR expression was analyzed by enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction.

RESULTS

LPS, PGN, and TNF-α induced an increased release of IL-8 and TNF-α in the AMs in all the groups independent of smoking or disease. These responses were inhibited by a glucocorticosteroid (Bud) in all the three groups, except PGN-induced IL-8 secretion in smokers without COPD. Bud increased TLR2 expression in the healthy controls and smokers without COPD. Costimulation of TLR ligands and Bud significantly enhanced TLR2 mRNA expression in both groups of smokers compared with TLR ligands alone. In smokers, costimulation with PGN and Bud significantly increased TLR2 expression when compared with Bud alone. On stimulation with the TLR4 agonist, LPS downregulated TLR4 mRNA expression in all the three groups.

CONCLUSION

The combination of glucocorticosteroids with TLR ligands can increase TLR2 expression, thereby improving host defense in smokers. Also this combination can decrease the secretion of proinflammatory cytokines and chemokines as an anti-inflammatory response. Our findings indicate that glucocorticosteroid therapy strengthens immune defense pathways, which may have implication during exacerbation caused by microorganisms.

Co-spray dried resveratrol and budesonide inhalation formulation for reducing inflammation and oxidative stress in rat alveolar macrophages

Oxidative stress is instrumental in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Novel therapeutic strategies that target macrophages, based on the use of antioxidant compounds, could be explored to improve corticosteroid responses in COPD patients. In this study, inhalable microparticles containing budesonide (BD) and resveratrol (RES) were prepared and characterized. This approach was undertaken to develop a multi-drug inhalable formulation with anti-oxidant and anti-inflammatory activities for treatment of chronic lung diseases. The inhalable microparticles containing different ratios of BD and RES were prepared by spray drying. The physico-chemical properties of the formulations were characterized in terms of surface morphology, particle size, physical and thermal stability. Additionally, in vitro aerosol performances of these formulations were evaluated with the multi-stage liquid impinger (MSLI) at 60 and 90 l/min, respectively. The cytotoxicity effect of the formulations was evaluated using rat alveolar macrophages. The biological responses of alveolar macrophages in terms of cytokine expressions, nitric oxide (NO) production and free radical scavenging activities were also tested. The co-spray dried (Co-SD) microparticles of all formulations exhibited morphologies appropriate for inhalation administration. Analysis of the deposition profiles showed an increase in aerosol performance proportional to BD concentration. Cell viability assay demonstrated that alveolar macrophages could tolerate a wide range of RES and BD concentrations. In addition, RES and BD were able to decrease the levels of tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS) induced alveolar macrophages. This study has successfully established the manufacture of Co-SD formulations of RES and BD with morphology and aerosol properties suitable for inhalation drug delivery, negligible in vitro toxicity and enhanced efficacy to control inflammation and oxidative stress in LPS-induced alveolar macrophages.

The Impact of Exogenous Factors on Respiratory Pathogen-Induced Innate Alveolar Macrophage Responses in COPD

Alveolar macrophages in chronic obstructive pulmonary disease (COPD) have fundamentally impaired innate immune responses to toll-like receptor (TLR) ligands of nontypeable Haemophilus influenzae (NTHI). However, whether dysfunctional inflammatory responses in COPD extend to macrophage interactions with intact respiratory pathogens beyond NTHI has not been explored. Furthermore, the influences of exogenous factors, including active smoking and medications, on pathogen-induced innate immune responses have only begun to be investigated. We hypothesized that distinct alveolar macrophage impairments in COPD are not limited to NTHI TLR ligands and that active smoking and select COPD medications modulate innate responses. Alveolar macrophages, obtained from COPD ex-smokers (n = 32) and active smokers (n = 64) by bronchoalveolar lavage (BAL), were incubated with NTHI, Moraxella catarrhalis, and Streptococcus pneumoniae, and with TLR2 and TLR4 ligands. Elicited IL-8 and TNF-α were measured by multianalyte microsphere flow cytometry to determine proinflammatory responsiveness. Induced IL-8, but not TNF-α, was greater from alveolar macrophages of active smokers compared with ex-smokers, in response to NTHI (p = 0.04), M. catarrhalis (p = 0.003), and S. pneumoniae (p = 0.03). Both IL-8 and TNF-α induction by TLR2 and TLR4 ligands were greater in active smokers. While intergroup NTHI- and M. catarrhalis-induced TNF-α levels were no different, they were notably lower among ex-smokers taking anticholinergic medications (p < 0.04 for each), but not with any other bronchoactive medications. Our results support a paradigm of distinct immunologic responses of COPD alveolar macrophages of ex- and active smokers to diverse respiratory pathogens and highlight a subset of ex-smokers whose diminished alveolar macrophage responsiveness may be associated with anticholinergic agents.

Corticosteroid insensitive alveolar macrophages from asthma patients; synergistic interaction with a p38 mitogen-activated protein kinase (MAPK) inhibitor

AIMS

Some asthma patients remain symptomatic despite using high doses of inhaled corticosteroids (ICS). We used alveolar macrophages to identify individual patients with insensitivity to corticosteroids and to evaluate the anti-inflammatory effects of a p38 mitogen-activated protein kinase (MAPK) inhibitor combined with a corticosteroid on these cells.

METHODS

Alveolar macrophages from 27 asthma patients (classified according to the Global Initiative for Asthma (GINA) treatment stage. Six GINA1, 10 GINA2 and 11 GINA3/4) were stimulated with lipoploysaccharide (LPS) (1 μg ml(-1)). The effects of dexamethasone (dex 1-1000 nm), the p38 MAPK inhibitor 1-(5-tert-butyl-2-p-tolyl-2Hpyrazol-3-yl)-3(4-(2-morpholin-4-yl-ethoxy)naphthalen-1-yl)urea (BIRB-796 1-1000 nm) and both drugs combined at all concentrations on supernatant TNFα, IL-6 and CXCL-8 concentrations were analyzed by ELISA. Dose-sparing and efficacy enhancing effects of combination treatment were determined.

RESULTS

Dexamethasone reduced LPS-induced TNFα, IL-6 and CXCL-8 in all groups, but maximum inhibition was significantly reduced for GINA3/4 compared with GINA2 and GINA1 (P < 0.01). A subgroup of corticosteroid insensitive patients with a reduced effect of dexamethasone on cytokine secretion were identified. BIRB-796 in combination with dexamethasone significantly increased cytokine inhibition compared with either drug alone (P < 0.001) in all groups. This effect was greater in corticosteroid insensitive compared with sensitive patients. There were significant synergistic dose-sparing effects (P < 0.05) for the combination treatment on inhibition of TNFα, IL-6 and CXCL-8 in all groups. There was also significant efficacy enhancing benefits (P < 0.05) on TNFα and IL-6.

CONCLUSIONS

p38 MAPK inhibitors synergistically enhance efficacy of corticosteroids in macrophages from asthma patients. This effect is greater in corticosteroid insensitive asthma patients, suggesting that this class of drug should be targeted to this patient phenotype.

Dissociation between systemic and pulmonary anti-inflammatory effects of dexamethasone in humans

Aims

The local pulmonary inflammatory response has a different temporal and qualitative profile compared with the systemic inflammatory response. Although glucocorticoids substantially downregulate the systemic release of acute‐phase mediators, it is not clear whether they have comparable inhibitory effects in the human lung compartment. Therefore, we compared the anti‐inflammatory effects of a pure glucocorticoid agonist, dexamethasone, on bronchoalveolar lavage and blood cytokine concentrations in response to bronchially instilled endotoxin.

Methods

In this randomized, double‐blind and placebo‐controlled trial, 24 volunteers received dexamethasone or placebo and had endotoxin instilled into a lung segment and saline instilled into a contralateral segment, followed by bronchoalveolar lavage.

Results

Bronchially instilled endotoxin induced a local and systemic inflammatory response. Dexamethasone strongly blunted the systemic interleukin (IL) 6 and C‐reactive protein release. In sharp contrast, dexamethasone left the local release of acute‐phase mediators in the lungs virtually unchanged: bronchoalveolar lavage levels of IL‐6 were only 18% lower and levels of IL‐8 were even higher with dexamethasone compared with placebo, although the differences between treatments were not statistically significant (P = 0.07 and P = 0.08, respectively). However, dexamethasone had inhibitory effects on pulmonary protein extravasation and neutrophil migration.

Conclusions

The present study demonstrated a remarkable dissociation between the systemic anti‐inflammatory effects of glucocorticoids and its protective effects on capillary leak on the one hand and surprisingly low anti‐inflammatory effects in the lungs on the other.

Metabolic changes of H2S in smokers and patients of COPD which might involve in inflammation, oxidative stress and steroid sensitivity

Oxidative stress and inflammation play crucial role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Most patients with COPD show a poor response to corticosteroids. Hydrogen sulfide (H2S ) has been implicated in the pathogenesis of COPD, but its expression and effects in lung tissue from COPD patients are not clear. In peripheral lung tissue samples from 24 patients, we found that compared with nonsmokers, the protein level of cystathionine-γ-lyase (CSE) was decreased in smokers and COPD patients. CSE mRNA increased but cystathionine-β-synthase (CBS) mRNA decreased in COPD patients. H2S donors increased glutathione and superoxide dismutase in CS exposed U937 cells and inhibited CS-induced TNF-α and IL-8 secretion. Dexamethasone alone had no effect on lipopolysaccharide (LPS) induced TNF-α release by alveolar macrophages from CS exposed rats, however the combination of dexamethasone and H2S donor significantly inhibited TNF-α release. Thus, H2S metabolism is altered in lung tissue of smokers and COPD patients. Supplementation of H2S protects against CS-induced oxidative stress and inflammation in macrophages and H2S on steroid sensitivity deserves further investigation.

The effects of corticosteroids on COPD lung macrophages: a pooled analysis

BACKGROUND

There is large variation in the therapeutic response to inhaled corticosteroids (ICS) in COPD patients. We present a pooled analysis of our previous studies investigating the effects of corticosteroids on lung macrophages, in order to robustly determine whether corticosteroid sensitivity in COPD cells is reduced compared to controls, and also to evaluate the degree of between individual variation in drug response.

METHODS

Data from 20 never smokers (NS), 27 smokers (S) and 45 COPD patients was used. Lung macropahges had been stimulated with lipopolysaccharide (LPS), with or without the corticosteroid dexamethasone, and tumour necrosis factor (TNF)-α, interleukin (IL)-6 and chemokine C-X-C motif ligand (CXCL) 8 production was measured.

RESULTS

There was no difference in the anti-inflammatory effects of corticosteroids when comparing group mean data of COPD patients versus controls. The inhibition of TNF-α and IL-6 was greater than CXCL8. The effects of corticosteroids varied considerably between subjects, particularly at lower corticosteroid concentrations.

CONCLUSIONS

We confirm that overall corticosteroid sensitivity in COPD lung macrophages is not reduced compared to controls. The varied effect of corticosteroids between subjects suggests that some individuals have an inherently poor corticosteroid response. The limited suppression of lung macrophage derived CXCL8 may promote neutrophilic inflammation in COPD.

Lung inflammation changes and oxidative stress induced by cigarette smoke exposure in guinea pigs affected by Zataria multiflora and its constituent, carvacrol

Background

Chronic obstructive pulmonary disease (COPD) is an epidemic and progressive health problem which is mainly a consequence of cigarette smoking, and associated with lung inflammation. Anti-inflammatory property of Zataria multiflora (Z. multiflora) and its constituent, carvacrol was shown in various inflammatory disorders previously. Therefore, in the present study, the effects of the plant and its constituent, carvacrol, on lung inflammation changes and oxidative stress, in guinea pigs model of COPD were evaluated.

Methods

Nine groups of animals including control, COPD, COPD + drinking water containing three concentrations of extract of Z. multiflora (0.4, 0.8, and 1.6 mg/mL), COPD + drinking water containing three concentrations of carvacrol (60, 120, and 240 μg/mL), and COPD + dexamethasone (50 μg/mL) were studied. For inducing COPD, animals were exposed to cigarette smoke for 3 months. Thiol groups, IL-8, total and differential WBC were measured in broncho-alveolar lavage fluid (BALF) (n = 6 for each group).

Results

Total WBC, eosinophils, and neutrophils counts as well as the levels of IL-8 in BALF were significantly increased but thiol group was decreased in COPD compared to the control group (p < 0.05 to p < 0.001). Total WBC and IL-8 in all treated COPD groups, thiol group, eosinophils and neutrophils counts in treated groups with dexamethasone and two higher concentrations of the Z. multiflora and carvacrol were significantly improved compared to non-treated COPD group (p < 0.05 to p < 0.001). Lymphocyte count in treated groups with dexamethasone, highest concentration of Z. multiflora, and two higher concentration of carvacrol was also significantly higher than non-treated group (p < 0.05 to p < 0.001).

Conclusions

A preventive effect of Z. multiflora extract and its constituent carvacrol on lung inflammation changes and oxidative stress in animal model of COPD was suggested.

S100A8, S100A9 and S100A12 activate airway epithelial cells to produce MUC5AC via extracellular signal-regulated kinase and nuclear factor-κB pathways

Airway mucus hyperproduction is a common feature of chronic airway diseases such as severe asthma, chronic obstructive pulmonary disease and cystic fibrosis, which are closely associated with neutrophilic airway inflammation. S100A8, S100A9 and S100A12 are highly abundant proteins released by neutrophils and have been identified as important biomarkers in many inflammatory diseases. Herein, we report a new role for S100A8, S100A9 and S100A12 for producing MUC5AC, a major mucin protein in the respiratory tract. All three S100 proteins induced MUC5AC mRNA and the protein in normal human bronchial epithelial cells as well as NCI-H292 lung carcinoma cells in a dose-dependent manner. A Toll-like receptor 4 (TLR4) inhibitor almost completely abolished MUC5AC expression by all three S100 proteins, while neutralization of the receptor for advanced glycation end-products (RAGE) inhibited only S100A12-mediated production of MUC5AC. The S100 protein-mediated production of MUC5AC was inhibited by the pharmacological agents that block prominent signalling molecules for MUC5AC expression, such as mitogen-activated protein kinases, nuclear factor-κB (NF-κB) and epidermal growth factor receptor. S100A8, S100A9 and S100A12 equally elicited both phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear translocation of NF-κB/degradation of cytosolic IκB with similar kinetics through TLR4. In contrast, S100A12 preferentially activated the ERK pathway rather than the NF-κB pathway through RAGE. Collectively, these data reveal the capacity of these three S100 proteins to induce MUC5AC production in airway epithelial cells, suggesting that they all serve as key mediators linking neutrophil-dominant airway inflammation to mucin hyperproduction.

Standardization of a human organ culture model of intestinal inflammation and its application for drug testing

Targeting early molecular events in intestinal inflammation may represent a useful therapeutic strategy for maintaining remission in inflammatory bowel disease. Recently, we established an intestinal organ culture model (LEL model), which allows to study the initiation of an intestinal inflammatory response in human tissue. In this model, EDTA-mediated depletion of epithelial cells of colonic mucosa results in an instantaneous inflammatory response in resident lamina propria cells, which shows features of intestinal inflammation in vivo. Furthermore, activated immune cells emigrate from the lamina propria onto the luminal side of the basement membrane. Here, we standardize the LEL model and explore its suitability for drug testing. To this end, human mucosal punches of defined surface area were prepared, depleted of epithelial cells, and cultured at an optimized ratio of medium volume/punch area. The intra-assay variability of measurements of inflammatory parameters ranged from 13% for cell migration to 19% for secretion and 30% for tissue gene expression, respectively, of the inflammatory mediators IL-8 and IL-6. Importantly, known suppressive effects of dexamethasone, a drug employed for the treatment of inflammatory bowel diseases, on leucocyte migration, IL8, IL6, and TNF-α production as well as CD86 surface expression by myeloid cells were observed in this model. In conclusion, the present results suggest that the LEL model may represent a useful human experimental system not only for studying initial activation mechanisms in intestinal inflammation but also for evaluating drug compounds for the treatment of mucosal inflammation.

Inhaled corticosteroids and pneumonia in chronic obstructive pulmonary disease

Inhaled corticosteroids are widely used in chronic obstructive pulmonary disease (COPD) and, in combination with long-acting β2 agonists, reduce exacerbations and improve lung function and quality of life. However, inhaled corticosteroids have been linked with an increased risk of pneumonia in individuals with COPD, but the magnitude of this risk, the effects of different preparations and doses, and the mechanisms of this effect remain unclear. Therefore, making informed clinical decisions--balancing the beneficial and adverse effects of inhaled corticosteroids in individuals with COPD--is difficult. Understanding of the mechanisms of increased pneumonia risk with inhaled corticosteroids is urgently needed to clarify their role in the management of COPD and to aid the development of new, safer therapies.

Increased levels of soluble interleukin-6 receptor and CCL3 in COPD sputum

Background

COPD patients have increased numbers of macrophages and neutrophils in the lungs. Interleukin-6 (IL-6) trans-signaling via its soluble receptor sIL-6R, governs the influx of innate immune cells to inflammatory foci through regulation of the chemokine CCL3. We hypothesized that there would be enhanced levels of IL-6, sIL-6R and CCL3 in COPD sputum.

Methods

59 COPD patients, 15 HNS and 15 S underwent sputum induction and processing with phosphate buffered saline to obtain supernatants for IL-6, sIL-6R and CCL3 analysis. Cytoslides were produced for differential cell counting and immunocytochemistry (COPD; n = 3) to determine cell type surface expression of the CCL3 receptors CCR5 and CCR1.

Results

COPD patients expressed higher levels (p < 0.05) of sIL-6R and CCL3 compared to controls (sIL-6R medians pg/ml: COPD 166.4 vs S 101.1 vs HNS 96.4; CCL3 medians pg/ml: COPD 117.9 vs S 0 vs HNS 2.7). COPD sIL-6R levels were significantly correlated with sputum neutrophil (r = 0.5, p < 0.0001) and macrophage (r = 0.3, p = 0.01) counts. Immunocytochemical analysis revealed that CCR5 and CCR1 were exclusively expressed on airway macrophages.

Conclusion

Enhanced airway generation of sIL-6R may promote IL-6 trans-signaling in COPD. Associated upregulation of CCL3 may facilitate the recruitment of macrophages into the airways by ligation of CCR1 and CCR5.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0103-4) contains supplementary material, which is available to authorized users.

Effect of the Zataria multiflora on systemic inflammation of experimental animals model of COPD

The effects of Zataria multiflora (Z. multiflora) on systemic inflammation in guinea pigs model of COPD were examined. Control animals, COPD (induced by exposing animals to cigarette smoke), COPD + drinking water containing three concentrations of the extract of Z. multiflora, and COPD + dexamethasone were studied (n = 6 for each group). Serum levels of IL-8 and malondialdehyde (MDA), total blood WBC (P < 0.01 for all cases), and eosinophil counts (P < 0.05) were higher and weight changes (P < 0.05) were lower in the COPD group compared to controls. IL-8 level (P < 0.001) and weight changes (P < 0.01 to P < 0.001) in all treated groups with Z. multiflora and total WBC number and MDA level in treated groups with two higher concentrations of the extract and lymphocytes percentage (P < 0.05) in the highest concentration of Z. multiflora and dexamethasone (P < 0.05 to P < 0.001) were significantly improved compared to the COPD group. Results showed a preventive effect of hydroethanolic extract from Z. multiflora on all measured parameters in animals model of COPD which was comparable or even higher (in the highest concentration) compared to the effect of dexamethasone at the concentration used.

Effects of cigarette smoke on Toll-like receptor (TLR) activation of chronic obstructive pulmonary disease (COPD) macrophages

Chronic obstructive pulmonary disease (COPD) is characterized by an abnormal innate immune response. We have investigated the changes in the innate immune response of COPD alveolar macrophages exposed to both cigarette smoke and Toll-like receptor (TLR) stimulation. COPD and control alveolar macrophages were exposed to cigarette smoke extract (CSE) followed by TLR-2, -4 and -5 ligands [Pam3CSK4, lipopolysaccharide (LPS) and phase I flagellin (FliC), respectively] or non-typeable Haemophilus influenzae (NTHi). CSE exposure suppressed TLR-induced tumour necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and regulated on activation, normal T cell expressed and secreted (RANTES) production in both COPD and control alveolar macrophages, but had no effect on interleukin 8 (CXCL8) production. Similarly, CSE suppressed NTHi-induced TNF-α but not NTHi-induced CXCL8 production in COPD alveolar macrophages. Gene expression analysis showed that CSE suppressed LPS-induced TNF-α transcription but not CXCL8 transcription in COPD alveolar macrophages. The dampening effect of CSE on LPS-induced cytokine production was associated with a reduction in p38, extracellular signal regulated kinase (ERK) and p65 activation. In conclusion, CSE caused a reduced innate immune response in COPD alveolar macrophages, with the exception of persistent CXCL8 production. This could be a mechanism by which alveolar macrophages promote neutrophil chemotaxis under conditions of oxidative stress and bacterial exposure.

Corticosteroid effects on COPD alveolar macrophages: dependency on cell culture methodology

It is unclear whether cell culture methodology affects the corticosteroid sensitivity of chronic obstructive pulmonary disease (COPD) alveolar macrophages. We compared the effect of a short and a long isolation procedure on corticosteroid inhibition of lipopolysaccharide (LPS) stimulated cytokine release from COPD alveolar macrophages. We also investigated signalling pathways associated with macrophage activation during cell isolation. Macrophages cultured using a short isolation protocol released higher unstimulated levels of tumour necrosis factor (TNF)-α and chemokine C-X-C motif ligand (CXCL) 8; these macrophages were less sensitive to corticosteroid inhibition of LPS stimulated TNF-α and CXCL8 release when compared to a long isolation procedure. This was associated with increased p38 mitogen activated kinase (MAPK) activation. The p38 MAPK inhibitor, BIRB-796, significantly reduced unstimulated cytokine release. A key finding of this study was that both cell culture methods showed no difference in the corticosteroid sensitivity between COPD and control macrophages. We conclude that the culture of alveolar macrophages using a short isolation procedure alters cytokine production through p38 MAPK activation; this is associated with a change in corticosteroid sensitivity.

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.

Inflammatory responses of airway smooth muscle cells and effects of endothelin receptor antagonism

Endothelin receptor antagonists (ETRAs), authorized for pulmonary hypertension, have failed to prove their utility in chronic lung diseases with corticosteroid-resistant airway inflammation when applied at late disease stages with emphysema/fibrosis. Earlier administration might prove effective by targeting the interaction between airway inflammation and tissue remodeling. We hypothesized that human airway smooth muscle cells (HASMCs) participate in linking inflammation with remodeling and that associated genes become differentially suppressed by ambrisentan (A-receptor selective ETRA) and bosentan (nonselective/dual ETRA). Inflammatory responses of ex vivo-cultivated HASMCs to TNF-α were investigated by whole-genome microarray analyses. qRT-PCR and ELISA were used to test inflammatory and remodeling genes for sensitivity to bosentan and ambrisentan and to investigate differential sensitivities mechanistically. ETRA and corticosteroid effects were compared in HASMCs from patients with chronic obstructive pulmonary disease. TNF-α induced the expression of 18 cytokines/chemokines and five tissue remodeling genes involved in severe, corticosteroid-insensitive asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and/or pulmonary hypertension. Thirteen cytokines/chemokines, MMP13, and WISP1 were suppressed by ETRAs. Eight genes had differential sensitivity to bosentan and ambrisentan depending on the endothelin-B receptor impact on transcriptional regulation and mRNA stabilization. Chemokine (C-C motif) ligands 2 and 5, granulocyte macrophage colony-stimulating factor, and MMP13 had increased sensitivity to bosentan or bosentan/dexamethasone combination versus dexamethasone alone. Suppression of cytokine and remodeling gene expression by ETRAs was confirmed in TNF-α-activated human bronchial epithelial cells. HASMCs and human bronchial epithelial cells participate in the interaction of inflammation and tissue remodeling. This interaction is targeted differentially by selective and nonselective ETRAs, which could be used in therapies of chronic lung diseases with corticosteroid-resistant airway inflammation at early disease stages to attenuate inflammation-induced airway remodeling.

Evaluation of glucocorticoid receptor function in COPD lung macrophages using beclomethasone-17-monopropionate

Previous studies of glucocorticoid receptor (GR) function in COPD lung macrophages have used dexamethasone to evaluate inhibition of cytokine production. We have now used the clinically relevant corticosteroid beclomethasone-17-monopropionate (17-BMP) to assess GR function in COPD lung macrophages, and investigated the transactivation of glucocorticoid sensitive genes and GR phosphorylation in addition to cytokine production. Lung macrophages were purified from surgically acquired lung tissue, from patients with COPD, smokers, and non-smokers. The transactivation of glucocorticoid sensitive genes (FKBP51 and GILZ) by 17-BMP were analysed by polymerase chain reaction. 17-BMP suppression of LPS-induced TNFα, IL-6 and CXCL8 was measured by ELISA and GR phosphorylation was measured by immunohistochemistry and Western blot. 17-BMP reduced cytokine release in a concentration dependent manner, with >70% inhibition of all cytokines, and no difference between COPD patients and controls. Similarly, the transactivation of FKBP51 and GILZ, and GR phosphorylation was similar between COPD patients and controls. In this context, GR function in COPD lung macrophages is unaltered. 17-BMP effectively suppresses cytokine production in COPD lung macrophages.

Corticosteroid insensitivity is reversed by formoterol via phosphoinositide-3-kinase inhibition

BACKGROUND AND PURPOSE

Patients with chronic obstructive pulmonary disease (COPD) show a poor response to corticosteroids, which has been linked to oxidative stress. Here we show that the long-acting β(2) -agonist formoterol (FM) reversed corticosteroid insensitivity under oxidative stress via inhibition of phosphoinositide-3-kinase (PI3K) signalling.

EXPERIMENTAL APPROACH

Responsiveness to corticosteroids dexamethasone (Dex), budesonide (Bud) and fluticasone propionate (FP) was determined, as IC(50) values on TNF-α-induced interleukin 8 release, in U937 monocytic cell line treated with hydrogen peroxide (H(2) O(2) ) or peripheral blood mononuclear cells (PBMCs) from patients with COPD or severe asthma.

KEY RESULTS

PBMCs from severe asthma and COPD were less sensitive to Dex compared with those from healthy subjects. Both FM (10(-9)  M) and salmeterol (SM, 10(-8)  M) reversed Dex insensitivity in severe asthma, but only FM restored Dex sensitivity in COPD. Although H(2) O(2) exposure decreased steroid sensitivity in U937 cells, FM restored responsiveness to Bud and FP while the effects of SM were weaker. Additionally, FM, but not SM, partially inhibited H(2) O(2) -induced PI3Kδ-dependent (PKB) phosphorylation. H(2) O(2) decreased SM-induced cAMP production in U937 cells, but did not significantly affect the response to FM. The reduction of SM effects by H(2) O(2) was reversed by pretreatment with LY294002, a PI3K inhibitor, or IC87114, a PI3Kδ inhibitor.

CONCLUSION AND IMPLICATIONS

FM reversed oxidative stress-induced corticosteroid insensitivity and decreased β(2) adrenoceptor-dependent cAMP production via inhibition of PI3Kδ signalling. FM will be more effective than SM, when combined with corticosteroids, for the treatment of respiratory diseases under conditions of high oxidative stress, such as in COPD.

IFN-γ synergistically enhances LPS signalling in alveolar macrophages from COPD patients and controls by corticosteroid-resistant STAT1 activation

BACKGROUND AND PURPOSE

IFN-γ levels are increased in chronic obstructive airway disease (COPD) patients compared with healthy subjects and are further elevated during viral exacerbations. IFN-γ can 'prime' macrophages to enhance the response to toll-like receptor (TLR) ligands, such as LPS. The aim of this study was to examine the effect IFN-γ on corticosteroid sensitivity in alveolar macrophages (AM).

EXPERIMENTAL APPROACH

AM from non-smokers, smokers and COPD patients were stimulated with IFN-γ and/or LPS with or without dexamethasone. IL-6, TNF-α and IFN-γ-induced protein 10 kDa (IP-10) levels were measured by elisa, and Western blots were used to investigate the IFN-γ-stimulated Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathway. Real-time PCR and flow cytometry were used to investigate TLR levels following IFN-γ treatment.

KEY RESULTS

In all three subject groups, IFN-γ alone had no effect on IL-6 and TNF-α production but enhanced the effects of LPS on these cytokines. In contrast, IFN-γ alone increased the production of IP-10. IFN-γ increased TLR2 and TLR4 expression in AM. Cytokine induction and STAT1 activation by IFN-γ were insensitive to dexamethasone for all groups. The inhibition of JAK and STAT1 repressed all these IFN-γ effects.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrate that IFN-γ-induced STAT-1 signalling is corticosteroid resistant in AMs, and that targeting IFN-γ signalling by JAK inhibitors is a potentially novel anti-inflammatory strategy in COPD.

Comparison of the anti-inflammatory effects of Cilomilast, Budesonide and a p38 Mitogen activated protein kinase inhibitor in COPD lung tissue macrophages

Chronic Obstructive Pulmonary Disease (COPD) is a disease characterized by a largely irreversible airflow obstruction and a persistent, excessive inflammatory response. Alveolar macrophages (AMs) are increased in the lungs of COPD patients, and act as orchestrators of the inflammatory response, releasing a range of mediators to coordinate recruitment and activation of leukocytes. Attempts to treat the inflammatory component of COPD with anti-inflammatory drugs such as steroids has met with limited success. In this study, we compared the ability of the phosphodiesterase IV (PDEIV) inhibitor Cilomilast, the steroid Budesonide, and the p38 mitogen activated protein kinase inhibitor BIRB-796 to inhibit tumour necrosis factor alpha (TNFα) and interleukin 6 (IL-6) releases from AMs isolated from COPD lung transplant tissue. All studies were carried out with appropriate ethical approval and written, informed consent was obtained from each subject. Cilomilast had little effect on cytokine release from AMs. There was considerable variability in the responsiveness of AMs to Budesonide, with a subset of AMs responding poorly to Budesonide. BIRB-796 inhibited TNFα release from all AM donors, including those that responded poorly to steroids. Treatment with BIRB-796 and Budesonide together gave an additive decrease in TNFa release. These results suggest that a p38 inhibitor may provide advantages over existing anti-inflammatory treatments for COPD, either as an add-on to existing therapy, or to treat patients who respond poorly to steroids.

Quantitative GPCR and ion channel transcriptomics in primary alveolar macrophages and macrophage surrogates

BACKGROUND

Alveolar macrophages are one of the first lines of defence against invading pathogens and play a central role in modulating both the innate and acquired immune systems. By responding to endogenous stimuli within the lung, alveolar macrophages contribute towards the regulation of the local inflammatory microenvironment, the initiation of wound healing and the pathogenesis of viral and bacterial infections. Despite the availability of protocols for isolating primary alveolar macrophages from the lung these cells remain recalcitrant to expansion in-vitro and therefore surrogate cell types, such as monocyte derived macrophages and phorbol ester-differentiated cell lines (e.g. U937, THP-1, HL60) are frequently used to model macrophage function.

METHODS

The availability of high throughput gene expression technologies for accurate quantification of transcript levels enables the re-evaluation of these surrogate cell types for use as cellular models of the alveolar macrophage. Utilising high-throughput TaqMan arrays and focussing on dynamically regulated families of integral membrane proteins, we explore the similarities and differences in G-protein coupled receptor (GPCR) and ion channel expression in alveolar macrophages and their widely used surrogates.

RESULTS

The complete non-sensory GPCR and ion channel transcriptome is described for primary alveolar macrophages and macrophage surrogates. The expression of numerous GPCRs and ion channels whose expression were hitherto not described in human alveolar macrophages are compared across primary macrophages and commonly used macrophage cell models. Several membrane proteins known to have critical roles in regulating macrophage function, including CXCR6, CCR8 and TRPV4, were found to be highly expressed in macrophages but not expressed in PMA-differentiated surrogates.

CONCLUSIONS

The data described in this report provides insight into the appropriate choice of cell models for investigating macrophage biology and highlights the importance of confirming experimental data in primary alveolar macrophages.

Ex vivo stimulation of whole blood as a means to determine glucocorticoid sensitivity

PURPOSE

Glucocorticoids are commonly prescribed to treat a number of diseases including the majority of inflammatory diseases. Despite considerable interpersonal variability in response to glucocorticoids, an insensitivity rate of about 30%, and the risk of adverse side effects of glucocorticoid therapy, currently no assay is performed to determine sensitivity.

PATIENTS AND METHODS

Here we propose a whole blood ex vivo stimulation assay to interrogate known glucocorticoid receptor (GR) up- and downregulated genes to indicate glucocorticoid sensitivity. We have chosen to employ real-time PCR in order to provide a relatively fast and inexpensive assay.

RESULTS

We show that the GR-regulated genes, GILZ and FKBP51, are upregulated in whole blood by treatment with dexamethasone and that LPS-induction of cytokines (IL-6 and TNFα) are repressed by dexamethasone in a dose responsive manner. There is considerable interpersonal variability in the maximum induction of these genes but little variation in the EC(50) and IC(50) concentrations. The regulation of the GR-induced genes differs throughout the day whereas the suppression of LPS-induced cytokines is not as sensitive to time of day.

CONCLUSION

In all, this assay would provide a method to determine glucocorticoid receptor responsiveness in whole blood.

T lymphocyte insensitivity to corticosteroids in chronic obstructive pulmonary disease

BACKGROUND

There are increased numbers of activated lymphocytes in the lungs of chronic obstructive pulmonary disease (COPD) patients. The clinical benefits of corticosteroids in COPD patients are limited. Our hypothesis is that lymphocytes play a role in this corticosteroid insensitivity.

OBJECTIVES

To investigate the effects of the corticosteroid dexamethasone on lung lymphocyte cytokine production from patients with COPD compared to controls.

METHODS

Cultured airway lymphocytes obtained by bronchoscopy from healthy non-smokers (HNS), smokers (S) and COPD patients were stimulated with phytohaemagglutinin (PHA) & phorbol myristate acetate (PMA), +/- dexamethasone. Supernatants were assayed for interleukin (IL)-2 and interferon (IFN)γ. Immunofluoresence was used to analyse changes in CD8 glucocorticoid receptor (GRα and GRβ) expression.

RESULTS

The inhibition of PHA/PMA stimulated IFNγ production by dexamethasone was reduced in COPD patients compared to HNS (p < 0.05 at concentrations from 0.1-1 μM). There was also a significant reduction (p < 0.05) in the mean inhibitory effect at 1 μM in COPD patients (54.1%) compared to smokers (72.1%), and in smokers compared to HNS (85.5%). There was a numerically reduced effect of dexamethasone on IL-2 production that did not reach statistical significance. There was no difference in GRα and GRβ expression in follicular CD8 cells between COPD patients (50.9% and 30.4% respectively) and smokers (52.9% and 29.7% respectively).

CONCLUSIONS

IFNγ production from COPD airway lymphocytes is corticosteroid insensitive. This phenomenon may be important in the poor clinical response often observed with corticosteroids.

Reduced glucocorticoid receptor expression and function in airway neutrophils

Chronic Obstructive Pulmonary Disease (COPD) is a glucocorticoid resistant condition characterised by airway neutrophilia. Reduced glucocorticoid receptor (GR) expression in COPD airway neutrophils may be a mechanism that contributes to glucocorticoid resistance. Our objective was to investigate the expression and function of GR within COPD airway neutrophils. Dual-label immunofluorescence was used to analyse airway neutrophil expression of GR within peripheral lung tissue samples (11 COPD patients, 7 healthy non-smokers [NS]) and induced sputum (7 COPD patients, 7 NS). TNFα and CXCL8 release were measured in neutrophils isolated from induced sputum and peripheral blood (7 COPD patients) in the presence of dexamethasone. In lung tissue, GR was abundantly expressed in macrophages and lymphocytes, but very low expression was observed in neutrophils (means 6.8% and 4.3% in COPD patients and NS respectively). Similarly low expression was observed in sputum neutrophils (means 3.8% and 6.9% in COPD patients and NS respectively). In contrast, GR was expressed by 100% of blood neutrophils. Dexamethasone had less suppressive effect on TNFα and CXCL8 production in vitro by neutrophils from induced sputum compared to neutrophils from paired blood samples. Airway neutrophils have low expression of GR in both COPD patients and controls. The effects of glucocorticoids on cytokine production from airway neutrophils are reduced. Increased numbers of airway neutrophils lacking GR may contribute to glucocorticoid resistance in COPD patients.

Immediate diagnosis of ventriculits: evaluation of parameters independent of microbiological culture

BACKGROUND

Generally accepted reference values in CSF diagnostics are not valid in cerebrospinal fluid (CSF) containing large amounts of blood. Residual blood may obscure ventriculitis as diagnostics largely depend on parameters such as cell count, lactic acid and total protein measurement. We sought to improve the diagnostics by evaluating a cytokine panel and soluble CD62L as markers of ventriculitis. In addition, we tested an algorithm of established parameters to predict ventriculitis in a specific patient collective.

METHODS

Analysis was performed on ventricular CSF samples from 50 consecutive patients. Gram staining, microbiological culture, total cell count, total protein and CD62L expression on neutrophil granulocytes were analysed immediately. Cytokines and soluble CD62L were measured by flow cytometry.

FINDINGS

Positive culture was detected in ten patients. Of all parameters tested only IL1-beta, IL8 and CD62L on neutrophils were significantly different between culture-positive and -negative patients. The highest predictive value was obtained when analysing IL1-beta. The predictive value of a parameter combination (IL6 in CSF, C-reactive protein and leukocytes in periphereal blood) was comparable to IL1-beta. Half of the patients in this analysis were identified as culture positive because of the lack of inflammatory response.

CONCLUSIONS

IL1-beta and perhaps also IL8 provide very good analytical performance when looking for ventriculitis in patients with residual blood in CSF. Turn-around time is short, and results could be reported within 1 h for 24 h a day. In some patients application of glucocorticoids may result in restricted inflammatory response. Even in these patients IL1-beta provides a reliable parameter for the immediate diagnosis of ventriculitis.