Mitochondrial dysfunction increases pro-inflammatory cytokine production and impairs repair and corticosteroid responsiveness in lung epithelium

COPD is characterized by chronic lung inflammation and irreversible lung tissue damage. Inhaled noxious gases, including cigarette smoke, are the major risk factor for COPD. Inhaled smoke first encounters the epithelial lining of the lungs, causing oxidative stress and mitochondrial dysfunction. We investigated whether a mitochondrial defect may contribute to increased lung epithelial pro-inflammatory responses, impaired epithelial repair and reduced corticosteroid sensitivity as observed in COPD. We used wild-type alveolar epithelial cells A549 and mitochondrial DNA-depleted A549 cells (A549 Rho-0) and studied pro-inflammatory responses using (multiplex) ELISA as well as epithelial barrier function and repair (real-time impedance measurements), in the presence and absence of the inhaled corticosteroid budesonide. We observed that A549 Rho-0 cells secrete higher levels of pro-inflammatory cytokines than wild-type A549 cells and display impaired repair upon wounding. Budesonide strongly suppressed the production of neutrophil attractant CXCL8, and promoted epithelial integrity in A549 wild-type cells, while A549 Rho-0 cells displayed reduced corticosteroid sensitivity compared to wild-type cells. The reduced corticosteroid responsiveness may be mediated by glycolytic reprogramming, specifically glycolysis-associated PI3K signaling, as PI3K inhibitor LY294002 restored the sensitivity of CXCL8 secretion to corticosteroids in A549 Rho-0 cells. In conclusion, mitochondrial defects may lead to increased lung epithelial pro-inflammatory responses, reduced epithelial repair and reduced corticosteroid responsiveness in lung epithelium, thus potentially contributing to the pathogenesis of COPD

Gene expression profiling of bronchial brushes is associated with the level of emphysema measured by computed tomography-based parametric response mapping

Parametric response mapping (PRM) is a computed tomography (CT)-based method to phenotype patients with chronic obstructive pulmonary disease (COPD). It is capable of differentiating emphysema-related air trapping with nonemphysematous air trapping (small airway disease), which helps to identify the extent and localization of the disease. Most studies evaluating the gene expression in smokers and COPD patients related this to spirometric measurements, but none have investigated the relationship with CT-based measurements of lung structure. The current study aimed to examine gene expression profiles of brushed bronchial epithelial cells in association with the PRM-defined CT-based measurements of emphysema (PRM(Emph)) and small airway disease (PRM(fSAD)). Using the Top Institute Pharma (TIP) study cohort (COPD = 12 and asymptomatic smokers = 32), we identified a gene expression signature of bronchial brushings, which was associated with PRM(Emph) in the lungs. One hundred thirty-three genes were identified to be associated with PRM(Emph). Among the most significantly associated genes, CXCL11 is a potent chemokine involved with CD8(+) T cell activation during inflammation in COPD, indicating that it may play an essential role in the development of emphysema. The PRM(Emph) signature was then replicated in two independent data sets. Pathway analysis showed that the PRM(Emph) signature is associated with proinflammatory and notch signaling pathways. Together these findings indicate that airway epithelium may play a role in the development of emphysema and/or may act as a biomarker for the presence of emphysema. In contrast, its role in relation to functional small airways disease is less clear

Neutrophilic Asthma Is Associated With Smoking, High Numbers of IRF5+, and Low Numbers of IL10+ Macrophages

Asthma is a heterogenous disease with different inflammatory subgroups that differ in disease severity. This disease variation is hampering treatment and development of new treatment strategies. Macrophages may contribute to asthma phenotypes by their ability to activate in different ways, i.e., T helper cell 1 (Th1)-associated, Th2-associated, or anti-inflammatory activation. It is currently unknown if these different types of activation correspond with specific inflammatory subgroups of asthma. We hypothesized that eosinophilic asthma would be characterized by having Th2-associated macrophages, whereas neutrophilic asthma would have Th1-associated macrophages and both having few anti-inflammatory macrophages. We quantified macrophage subsets in bronchial biopsies of asthma patients using interferon regulatory factor 5 (IRF5)/CD68 for Th1-associated macrophages, CD206/CD68 for Th2-associated macrophages and interleukin 10 (IL10)/CD68 for anti-inflammatory macrophages. Macrophage subset percentages were investigated in subgroups of asthma as defined by unsupervised clustering using neutrophil/eosinophil counts in sputum and tissue and forced expiratory volume in 1 s (FEV1). Asthma patients clustered into four subgroups: mixed-eosinophilic/neutrophilic, paucigranulocytic, neutrophilic with normal FEV1, and neutrophilic with low FEV1, the latter group consisting mainly of smokers. No differences were found for CD206+ macrophages within asthma subgroups. In contrast, IRF5+ macrophages were significantly higher and IL10+ macrophages lower in neutrophilic asthmatics with low FEV1 as compared to those with neutrophilic asthma and normal FEV1 or mixed-eosinophilic asthma. This study shows that neutrophilic asthma with low FEV1 is associated with high numbers of IRF5+, and low numbers of IL10+ macrophages, which may be the result of combined effects of smoking and having asthma.</p

Two sisters with lung emphysema

BACKGROUND: α1-antitrypsin is an antiprotease that is mainly produced in the liver; it plays a crucial role in the protection of lung parenchyma against the destructive effects of proteases. Mutations in the α1-antitrypsin gene can cause α1-antitrypsin deficiency. Individuals homozygous for the Z-genotype have drastically lowered serum α1-antitrypsine concentrations and often develop lung emphysema at an early age.CASE DESCRIPTION: A 38-year-old woman and her 43-year-old sister both developed lung emphysema at an early age; this could be attributed to severe α1-antitrypsin deficiency. The only treatment for this condition is α1-antitrypsin supplement therapy, but this therapy is not reimbursed by health insurance companies in the Netherlands.CONCLUSION: α1-antitrypsin deficiency is a relatively rare cause of lung emphysema and can be seen as an orphan phenotype of chronic obstructive pulmonary disease (COPD). We appeal for reconsideration of coverage of α1-antitrypsine supplement therapy by basic health insurance in the Netherlands, on the basis of a recent randomised placebo-controlled study in which the protective effect of this therapy on progressive emphysema was demonstrated by CT lung densitometry.</p

Bronchial Thermoplasty Induced Airway Smooth Muscle Reduction and Clinical Response in Severe Asthma:The TASMA Randomized Trial

RATIONALE: Bronchial Thermoplasty (BT) is a bronchoscopic treatment for severe asthma targeting airway smooth muscle (ASM). Observational studies have shown ASM mass reduction after BT but appropriate control groups are lacking. Furthermore, as treatment response is variable, identifying optimal candidates for BT treatment is important. AIMS: First, to assess the effect of BT on ASM mass and second, to identify patient characteristics that correlate with BT-response. METHODS: Severe asthma patients (n=40) were randomized to immediate (n=20) or delayed (n=20) BT-treatment. Prior to randomization, clinical, functional, blood and airway biopsy data were collected. In the delayed control group, re-assessment, including biopsies, was performed after 6 months of standard clinical care, followed by BT. In both groups, post-BT data including biopsies were obtained after 6 months. ASM mass (% positive desmin or α-smooth muscle actin area in the total biopsy) was calculated with automated digital analyses software. Associations between baseline characteristics and Asthma Control and Asthma Quality of Life Questionnaire (ACQ/AQLQ) improvement were explored. RESULTS: Median ASM mass decreased by >50% in the immediate BT group (n=17) versus no change in the delayed control group (n=19) (p=0.0004). In the immediate group ACQ scores improved with -0.79 (-1.61;0.02 IQR) compared to 0.09 (-0.25;1.17 IQR) in the delayed group (p=0.006). AQLQ scores improved with 0.83 (-0.15;1.69 IQR) versus -0.02 (-0.77;0.75 IQR) (p=0.04). Treatment response in the total group (n=35) was positively associated with serum IgE and eosinophils, but not with baseline ASM mass. CONCLUSION: ASM mass significantly decreases after BT when compared to a randomized non-BT treated control group. Treatment response was associated with serum IgE and eosinophil levels but not with ASM mass. Clinical trial registration available at www.clinicaltrials.gov, ID:NCT0222539

Neutrophilic Asthma Is Associated With Smoking, High Numbers of IRF5+, and Low Numbers of IL10+ Macrophages

Asthma is a heterogenous disease with different inflammatory subgroups that differ in disease severity. This disease variation is hampering treatment and development of new treatment strategies. Macrophages may contribute to asthma phenotypes by their ability to activate in different ways, i.e., T helper cell 1 (Th1)-associated, Th2-associated, or anti-inflammatory activation. It is currently unknown if these different types of activation correspond with specific inflammatory subgroups of asthma. We hypothesized that eosinophilic asthma would be characterized by having Th2-associated macrophages, whereas neutrophilic asthma would have Th1-associated macrophages and both having few anti-inflammatory macrophages. We quantified macrophage subsets in bronchial biopsies of asthma patients using interferon regulatory factor 5 (IRF5)/CD68 for Th1-associated macrophages, CD206/CD68 for Th2-associated macrophages and interleukin 10 (IL10)/CD68 for anti-inflammatory macrophages. Macrophage subset percentages were investigated in subgroups of asthma as defined by unsupervised clustering using neutrophil/eosinophil counts in sputum and tissue and forced expiratory volume in 1 s (FEV1). Asthma patients clustered into four subgroups: mixed-eosinophilic/neutrophilic, paucigranulocytic, neutrophilic with normal FEV1, and neutrophilic with low FEV1, the latter group consisting mainly of smokers. No differences were found for CD206+ macrophages within asthma subgroups. In contrast, IRF5+ macrophages were significantly higher and IL10+ macrophages lower in neutrophilic asthmatics with low FEV1 as compared to those with neutrophilic asthma and normal FEV1 or mixed-eosinophilic asthma. This study shows that neutrophilic asthma with low FEV1 is associated with high numbers of IRF5+, and low numbers of IL10+ macrophages, which may be the result of combined effects of smoking and having asthma

Budesonide and fluticasone propionate differentially affect the airway epithelial barrier

Background: COPD patients have a higher risk of pneumonia when treated with fluticasone propionate (FP) than with placebo, and a lower risk with budesonide (BUD). We hypothesized that BUD and FP differentially affect the mucosal barrier in response to viral infection and/or cigarette smoke. Methods: We assessed protective effects of equivalent concentrations of BUD and FP on cytokine production and barrier function (electrical resistance) in human bronchial epithelial 16HBE cells and primary bronchial epithelial cells (PBECs) upon exposure to viral mimetic poly-(I:C) and/or cigarette smoke extract (CSE) or epidermal growth factor (EGF). Results: BUD and FP were equally effective in suppressing poly-(I:C)-and/or CSE-induced IL-8 secretion in 16HBE and PBECs. Poly-(I:C) substantially decreased electrical resistance in 16HBE cells and both BUD and FP fully counteracted this effect. However, FP hardly affected 16HBE barrier dysfunction induced by CSE with/without poly-(I:C), whereas BUD (16 nM) provided full protection, an effect likely mediated by affecting EGFR-downstream target GSK-3 beta. Similarly, BUD, but not FP, significantly improved CSE-induced barrier dysfunction in PBECs. Finally, BUD, but not FP, exerted a modest but significant protective effect against Streptococcus Pneumoniae-induced barrier dysfunction, and BUD, but not FP, prevented cellular adhesion and/or internalization of these bacteria induced by poly-(I:C) in 16HBE. Conclusions: Collectively, both BUD and FP efficiently control epithelial pro-inflammatory responses and barrier function upon mimicry of viral infection. Of potential clinical relevance, BUD more effectively counteracted CSE-induced barrier dysfunction, reinforcing the epithelial barrier and potentially limiting access of pathogens upon smoking in vivo

Cytokine Profiles in Asthma Families Depend on Age and Phenotype

Background: Circulating cytokine patterns may be relevant for the diagnosis of asthma, for the discrimination of certain phenotypes, and prognostic factors for exacerbation of disease. Methodology/Principal Findings: In this study we investigated serum samples from 944 individuals of 218 asthma-affected families by a multiplex, microsphere based system detecting at high sensitivity eleven asthma associated mediators: eotaxin (CCL11), granulocyte macrophage stimulating factor (GM-CSF), interferon gamma (IFNγ), interleukin-4 (IL-4), IL-5, IL-8, IL-10, IL-12 (p40), IL-13, IL-17 and tumor necrosis factor alpha (TNFα). Single cytokine levels were largely similar between asthmatic and healthy individuals when analysing asthma as single disease entity. Regulatory differences between parental and pediatric asthma were reflected by six of the eleven mediators analyzed (eotaxin, IL-4, IL-5, IL-10, IL-12, TNFα). IL-12 (p40) and IL-5 were the best predictor for extrinsic asthma in children with an increased odds ratio of 2.85 and 1.96 per log pg/ml increase (IL-12 (p40): 1.2-6.8, p = 0.019, and IL-5: 1.2-2.5, p = 0.025). Frequent asthma attacks in children are associated with elevated IL-5 serum levels (p = 0.013). Cytokine patterns seem to be individually balanced in both, healthy and diseased adults and children, with various cytokines correlating among each other (IL-17 and IFNγ (rs = 0.67), IL-4 and IL-5 (rs = 0.55), IFNγ and GM-CSF (rs = 0.54)). Conclusion/Significance: Our data support mainly an age- but also an asthma phenotype-dependent systemic immune regulation. © 2010 Pukelsheim et al