Christos Rossios

A protein deacetylase SIRT1 is a negative regulator of metalloproteinase-9

Inappropriate elevation of matrix metalloproteinase‐9 (MMP9) is reported to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). The object of this study was to identify the molecular mechanism underlying this increase of MMP9 expression, and here we show that oxidative stress‐dependent reduction of a protein deacetylase, SIRT1, known as a putative antiaging enzyme, causes elevation of MMP9 expression. A sirtuin inhibitor, splitomycin, and SIRT1 knockdown by RNA interference led an increase in MMP9 expression in human monocytic U937 cells and in primary sputum macrophages, which was detected by RT‐PCR, Western blot, activity assay, and zymography. In fact, the SIRT1 level was significantly decreased in peripheral lungs of patients with COPD, and this increase was inversely correlated with MMP9 expression and MMP9 promoter activation detected by a chromatin immunoprecipitation assay. H2O2 reduced SIRT1 expression and activity in U937 cells;furthermore, cigarette smoke exposure also caused reduction of SIRT1 expression in lung tissue of A/J mice, with concomitant elevation of MMP9. Intranasal treatment of a selective and novel SIRT1 small molecule activator, SRT2172, blocked the increase of MMP9 expression in the lung as well as pulmonary neutrophilia and the reduction in exercise tolerance. Thus, SIRT1 is a negative regulator of MMP9 expression, and SIRT1 activation is implicated as a novel therapeutic approach to treating chronic inflammatory diseases, in which MMP9 is abundant.— Nakamaru, Y., Vuppusetty, C., Wada, H., Milne, J. C., Ito, M., Rossios, C., Elliot, M., Hogg, J., Kharitonov, S., Goto, H., Bemis, J. E., Elliott, P., Barnes, P. J., Ito, K. A protein deacetylase SIRT1 is a negative regulator of metalloproteinase‐9. FASEB J. 23, 2810–2819 (2009).www.fasebj.org

Application of ’omics technologies to biomarker discovery in inflammatory lung diseases

Inflammatory lung diseases are highly complex in respect of pathogenesis and relationships between inflammation, clinical disease and response to treatment. Sophisticated large-scale analytical methods to quantify gene expression (transcriptomics), proteins (proteomics), lipids (lipidomics) and metabolites (metabolomics) in the lungs, blood and urine are now available to identify biomarkers that define disease in terms of combined clinical, physiological and patho-biological abnormalities. The aspiration is that these approaches will improve diagnosis, i.e. define pathological phenotypes, and facilitate the monitoring of disease and therapy, and also, unravel underlying molecular pathways. Biomarker studies can either select predefined biomarker(s) measured by specific methods or apply an “unbiased” approach involving detection platforms that are indiscriminate in focus. This article reviews the technologies presently available to study biomarkers of lung disease within the ’omics field. The contributions of the individual ’omics analytical platforms to the field of respiratory diseases are summarised, with the goal of providing background on their respective abilities to contribute to systems medicine-based studies of lung disease. Summary of the application of ’omics-based analytical platforms for biomarker discovery in inflammatory lung diseases http://ow.ly/mjGGc

A novel macrolide/fluoroketolide, solithromycin (CEM‐101), reverses corticosteroid insensitivity via phosphoinositide 3‐kinase pathway inhibition

Corticosteroid insensitivity is a major therapeutic problem for some inflammatory diseases including chronic obstructive pulmonary disease (COPD), and it is known to be induced by reduced histone deacetylase (HDAC)‐2 activities via activation of the phosphoinositide 3‐kinase (PI3K) pathway. The aim of this study is to evaluate effects of a novel macrolide/fluoroketolide, solithromycin (SOL, CEM‐101), on corticosteroid sensitivity induced by oxidative stress.

Long-acting fluticasone furoate has a superior pharmacological profile to fluticasone propionate in human respiratory cells.

Currently available glucocorticoids are relatively short acting and may be less effective in patients with chronic obstructive pulmonary disease (COPD) where high levels of oxidative stress are seen. Here we show that a novel glucocorticoid, fluticasone furoate (FF), has a longer duration of action in several cell systems compared with fluticasone propionate (FP) and budesonide, and unlike FP, FF is resistant to oxidative stress. FF had similar or slightly higher potency to FP and was 2-9 fold more potent than budesonide, when assessed at 4h, in inhibiting inflammatory cytokine production in epithelial cell lines (BEAS2B, A549), primary bronchial epithelial cells and a monocytic cell line (U937). The potency of FF was sustained beyond 16 h with or without washout compared with FP or budesonide, such that it showed a greater duration of action in this range of cellular assays. The activated YFP-conjugated glucocorticoid receptor was detectable in nuclei of FF treated BEAS2B cells for at least for 30 h, and FF had a longer duration of action than FP in inhibiting activation of transcription factors such as NF-κB and AP-1. In addition, FF showed superior effects to FP in peripheral blood mononuclear cells from patients with COPD and also in U937 cells or primary bronchial epithelial cells under conditions of oxidative stress. The longer duration of action and oxidative stress insensitivity of FF compared with FP has potential clinical implications for the control of inflammation in respiratory diseases, such as COPD.

Can we delay the accelerated lung aging in COPD? Anti-aging molecules and interventions.

Chronic obstructive pulmonary disease (COPD) has been recently characterized as a disease of accelerated lung aging. The prevalence of COPD is age-dependent suggesting an intimate relationship between the pathogenesis of COPD and aging. Lung function decline, the hallmark feature of COPD evolution, is more prominent with increasing age and this decline is greater in smoking individuals. One of the major goals of COPD pharmacotherapy is the development of drugs that would be able to result in a decrease of the decline in lung function over years. However, till nowadays smoking cessation is the only known intervention which is able to decelerate lung function decline. Several mechanisms of aging, including oxidative stress, inflammation and telomere shortening have been shown to be implicated in COPD. Furthermore, numerous anti-aging molecules, including sirtuins and Nrf-2 are reduced, and pathways such as mTOR and genes such as Klotho have also been shown to be abnormal in the lungs of COPD patients. The above mechanisms have been associated with the accelerated lung aging in COPD patients. Numerous therapeutic interventions have been studied in an attempt to reverse accelerated lung aging, and some of them have already been tested in clinical trials. The aim of the present review is to summarize the mechanisms associated with the accelerated lung aging in COPD and to provide information about the possible therapeutic implications targeting those mechanisms.

Sputum transcriptomics reveal upregulation of IL-1 receptor family members in patients with severe asthma

Background: Sputum analysis in asthmatic patients is used to define airway inflammatory processes and might guide therapy. Objective: We sought to determine differential gene and protein expression in sputum samples from patients with severe asthma (SA) compared with nonsmoking patients with mild/moderate asthma. Methods: Induced sputum was obtained from nonsmoking patients with SA, smokers/ex‐smokers with severe asthma, nonsmoking patients with mild/moderate asthma (MMAs), and healthy nonsmoking control subjects. Differential cell counts, microarray analysis of cell pellets, and SOMAscan analysis of sputum analytes were performed. CRID3 was used to inhibit the inflammasome in a mouse model of SA. Results: Eosinophilic and mixed neutrophilic/eosinophilic inflammation were more prevalent in patients with SA compared with MMAs. Forty‐two genes probes were upregulated (>2‐fold) in nonsmoking patients with severe asthma compared with MMAs, including IL‐1 receptor (IL‐1R) family and nucleotide‐binding oligomerization domain, leucine‐rich repeat and pyrin domain containing 3 (NRLP3) inflammasome members (false discovery rate < 0.05). The inflammasome proteins nucleotide‐binding oligomerization domain, leucine rich repeat and pyrin domain containing 1 (NLRP1), NLRP3, and nucleotide‐binding oligomerization domain (NOD)‐like receptor C4 (NLRC4) were associated with neutrophilic asthma and with sputum IL‐1&bgr; protein levels, whereas eosinophilic asthma was associated with an IL‐13–induced TH2 signature and IL‐1 receptor–like 1 (IL1RL1) mRNA expression. These differences were sputum specific because no activation of NLRP3 or enrichment of IL‐1R family genes in bronchial brushings or biopsy specimens in patients with SA was observed. Expression of NLRP3 and of the IL‐1R family genes was validated in the Airway Disease Endotyping for Personalized Therapeutics cohort. Inflammasome inhibition using CRID3 prevented airway hyperresponsiveness and airway inflammation (both neutrophilia and eosinophilia) in a mouse model of severe allergic asthma. Conclusion: IL1RL1 gene expression is associated with eosinophilic SA, whereas NLRP3 inflammasome expression is highest in patients with neutrophilic SA. TH2‐driven eosinophilic inflammation and neutrophil‐associated inflammasome activation might represent interacting pathways in patients with SA.

Sputum-to-serum hydrogen sulfide ratio in COPD

Objectives Hydrogen sulfide (H2S) is a gas produced by respiratory cells including smooth muscle cells and may play a role as a cellular gasotransmitter. We evaluated whether H2S levels in serum or sputum could represent a new biomarker of COPD in a cross-sectional study. Methods H2S levels in sputum and serum samples were measured using a sulfide-sensitive electrode in 64 patients with stable COPD (S-COPD), 29 COPD subjects during acute exacerbation (AE-COPD), 14 healthy smokers and 21 healthy non-smokers. Results Sputum H2S levels in AE-COPD subjects were higher than those in S-COPD, healthy smoking and non-smoking subjects (p<0.001), but serum H2S levels in AE-COPD were lower than those in S-COPD (p<0.001). Thus, the sputum-to-serum ratio of H2S (H2S ratio) in AE-COPD subjects were higher than those in stable COPD, healthy smoking and non-smoking subjects (p<0.001). In 14 COPD subjects whose H2S ratios were measured during and after an exacerbation, the mean ratio was increased during exacerbation (p<0.05). H2S ratio was positively correlated with St. Georges Respiratory Questionnaire score, sputum neutrophils and IL-6 and IL-8 levels in sputum and serum (p<0.01) but inversely correlated with sputum macrophages (%), FEV1%predicted and FEV1/FVC (p<0.01). The cut-off level of H2S ratio to indicate an exacerbation was ≥0.44 (sensitivity of 93.1% and specificity of 84.5%). Conclusions The ratio of sputum-to-serum levels of H2S may provide a useful marker of COPD indicative of obstructive neutrophilic inflammation and of potential ongoing exacerbation.

Sputum proteomics and airway cell transcripts of current and ex-smokers with severe asthma in U-BIOPRED: an exploratory analysis

Severe asthma patients with a significant smoking history have airflow obstruction with reported neutrophilia. We hypothesise that multi-omic analysis will enable the definition of smoking and ex-smoking severe asthma molecular phenotypes. The U-BIOPRED cohort of severe asthma patients, containing current-smokers (CSA), ex-smokers (ESA), nonsmokers and healthy nonsmokers was examined. Blood and sputum cell counts, fractional exhaled nitric oxide and spirometry were obtained. Exploratory proteomic analysis of sputum supernatants and transcriptomic analysis of bronchial brushings, biopsies and sputum cells was performed. Colony-stimulating factor (CSF)2 protein levels were increased in CSA sputum supernatants, with azurocidin 1, neutrophil elastase and CXCL8 upregulated in ESA. Phagocytosis and innate immune pathways were associated with neutrophilic inflammation in ESA. Gene set variation analysis of bronchial epithelial cell transcriptome from CSA showed enrichment of xenobiotic metabolism, oxidative stress and endoplasmic reticulum stress compared to other groups. CXCL5 and matrix metallopeptidase 12 genes were upregulated in ESA and the epithelial protective genes, mucin 2 and cystatin SN, were downregulated. Despite little difference in clinical characteristics, CSA were distinguishable from ESA subjects at the sputum proteomic level, with CSA patients having increased CSF2 expression and ESA patients showing sustained loss of epithelial barrier processes. Inflammatory, oxidative/ER stress and epithelial barrier pathways are differentially activated in current smoking and ex-smoking severe asthma patients http://ow.ly/BVv530j3iP3

The role of endosomal toll-like receptors in asthma.

ABSTRACT Asthma is a heterogeneous inflammatory disease caused by association of genetic and environmental factors and its incidence has significantly increased over the latest years. The clinical manifestations of asthma are the result of airway hyper‐reactivity to a variety of triggers such as aeroallergens, viral and bacterial components. Toll‐like receptors (TLRs) are pathogen associated molecular pattern receptors, which are also expressed in the lung tissue as well as in several cells of the innate and adaptive immune system. Ligation of TLRs results in alterations in the expression of several inflammatory and anti‐inflammatory mediators, which are known to be involved in the pathogenesis of asthma. The endosomal TLRs have been shown to be associated with the induction of asthmatic inflammation (TLR3), and with disease exacerbations (TLR7, TLR8 and TLR9). Targeting these receptors seems to be an effective choice for suppressing airway inflammation, eosinophilia and airway hyperresponsiveness in asthmatic patients. In this review we provide information regarding endosomal TLRs and their role in the pathogenesis of asthma as well as their potential use as targets for the development of novel treatments for the therapy of asthma.

Impaired innate immune gene profiling in airway smooth muscle cells from chronic cough patients

Chronic cough is associated with airway inflammation and remodelling. Abnormal airway smooth muscle cell (ASMC) function may underlie mechanisms of chronic cough. Our objective was to examine the transcriptome and focused secretome of ASMCs from chronic cough patients and healthy non-cough volunteers. ASMC gene expression profiling was performed at baseline and/or after stimulation with polyinosinic:polycytidylic acid (poly(I:C)) to mimic viral infection. Supernatants were collected for multiplex analysis. Our results showed no significant differentially expressed genes (DEGs, false discovery rate (FDR) <0.05) between chronic cough and healthy non-cough ASMCs at baseline. Poly(I:C) stimulation resulted in 212 DEGs (>1.5 fold-change, FDR <0.05) in ASMCs from chronic cough patients compared with 1674 DEGs in healthy non-cough volunteers. The top up-regulated genes included chemokine (C–X–C motif) ligand (CXCL) 11 (CXCL11), CXCL10, chemokine (C–C motif) ligand (CCL) 5 (CCL5) and interferon-induced protein 44 like (IFI44L) corresponding with inflammation and innate immune response pathways. ASMCs from cough subjects had enhanced activation of viral response pathways in response to poly(I:C) compared with healthy non-cough subjects, reduced activation of pathways involved in chronic inflammation and equivalent activation of neuroregulatory genes. The poly(I:C)-induced release of inflammatory mediators, including CXCL8, interleukin (IL)-6 and CXCL1, from ASMCs from cough patients was significantly impaired compared with healthy non-cough subjects. Addition of fluticasone propionate (FP) to poly(I:C)-treated ASMCs resulted in greater gene expression changes in healthy non-cough ASMCs. FP had a differential effect on poly(I:C)-induced mediator release between chronic cough and healthy non-cough volunteers. In conclusion, altered innate immune and inflammatory gene profiles within ASMCs, rather than infiltrating cells or nerves, may drive the cough response following respiratory viral infection.