Development of a primary airway epithelial cell culture model and explanted tissue archive to study the role of neutrophilic inflammation and airway remodelling in cystic fibrosis lung disease

Cystic fibrosis (CF) is the most common inherited life-limiting condition in the United Kingdom. Lung disease, involving retention of mucopurulent secretions, neutrophilic inflammation and endobronchial infection is the major cause of mortality. CF is caused by variants in the CF-transmembrane conductance regulator gene, however the exact pathogenesis of lung disease is not fully understood. Valid experimental models are therefore critical to advance research. I describe the establishment of a successful method to culture primary bronchial epithelial cells (PBECs) from explanted CF lungs removed at transplantation. This technique has yielded an important resource to further study the pathogenesis of CF lung disease. The cytokine interleukin-17 orchestrates the activity of neutrophils and increases mucin gene expression in BECs – two key features of CF lung disease. I demonstrate that interleukin-17 is increased in the airway of people with advanced CF lung disease. I also show evidence suggesting that neutrophils themselves may be a source of interleukin-17 potentially leading to an ever-increasing spiral of inflammation. In a CF mouse model ceramide accumulates in BECs and is associated with neutrophilic inflammation and susceptibility to Pseudomonas aeruginosa infection. Furthermore, amitriptyline treatment normalised ceramide, inflammation and susceptibility to infection. The role of ceramide is a complex area, however, with a divergence of opinion in the literature and paucity of human data. I demonstrate using immunohistochemistry that ceramide is increased in the lower airway epithelium in advanced CF lung disease compared to pulmonary hypertension and unused lung donors and is correlated with neutrophilic inflammation and increased in those colonised with Pseudomonas aeruginosa. Ceramide species C16:0, C18:0 and C20:0 but not C22:0 are increased in lung homogenates of CF lungs compared to pulmonary hypertension measured using the independent technique of high performance liquid chromatographymass spectrometry. Both interleukin-17 and ceramide represent important topics for further translational CF lung disease research.EThOS - Electronic Theses Online ServiceSpecial Trustees of Newcastle Hospitals : Medical Research Council/Cystic Fibrosis Trust Clinical Research Training FellowshipGBUnited Kingdo

Epidemiology of Nontuberculous Mycobacteria Infection in Children and Young People With Cystic Fibrosis: Analysis of UK Cystic Fibrosis Registry

Background Infection with nontuberculous mycobacteria (NTM) is of growing clinical concern in people with cystic fibrosis (CF). The epidemiology of infection in children and young people remains poorly understood. Our goal was to investigate the epidemiology of NTM infection in the pediatric age group using data from the UK CF Registry. Methods Data from 2010–2015 for individuals aged <16 years (23200 observations from 5333 unique individuals) were obtained. Univariate analysis of unique individuals comparing all key clinical factors and health outcomes to NTM status was performed. The significant factors that were identified were used to generate a multivariate logistic regression model that, following step-wise removal, generated a final parsimonious model. Results The prevalence of individuals with a NTM-positive respiratory culture increased every year from 2010 (45 [1.3%]) to 2015 (156 [3.8%]). Allergic bronchopulmonary aspergillosis (odds ratio [OR], 2.66; P = 5.0 × 10−8), age (OR, 1.08; P = 3.4 × 10−10), and intermittent Pseudomonas aeruginosa infection (OR, 1.51; P = .004) were significantly associated with NTM infection. Conclusions NTM infection is of increasing prevalence in the UK pediatric CF population. This study highlights the urgent need for work to establish effective treatment and prevention strategies for NTM infection in young people with CF

Scientific data mining, integration, and visualization

This report summarises the workshop on Scientific Data Mining, Integration and Visualization (SDMIV) held at the e-Science Institute, Edinburgh (eSI[1] ) on 24-25 October 2002, and presents a set of recommendations arising from the discussion that took place there. The aims of the workshop were threefold: (A) To inform researchers in the SDMIV communities of the infrastructural advances being made by computing initiatives, such as the Grid; (B) To feed back requirements from the SDMIV areas to those developing the computational infrastructure; and (C) To foster interaction among all these communities, since the coordinated efforts of all of them will be required to realise the potential for scientific knowledge extraction offered by e-science initiatives worldwide

Elevated Paracellular Glucose Flux across Cystic Fibrosis Airway Epithelial Monolayers Is an Important Factor for Pseudomonas aeruginosa Growth.

People with cystic fibrosis (CF) who develop related diabetes (CFRD) have accelerated pulmonary decline, increased infection with antibiotic-resistant Pseudomonas aeruginosa and increased pulmonary exacerbations. We have previously shown that glucose concentrations are elevated in airway surface liquid (ASL) of people with CF, particularly in those with CFRD. We therefore explored the hypotheses that glucose homeostasis is altered in CF airway epithelia and that elevation of glucose flux into ASL drives increased bacterial growth, with an effect over and above other cystic fibrosis transmembrane conductance regulator (CFTR)-related ASL abnormalities. The aim of this study was to compare the mechanisms governing airway glucose homeostasis in CF and non-CF primary human bronchial epithelial (HBE) monolayers, under normal conditions and in the presence of Ps. aeruginosa filtrate. HBE-bacterial co-cultures were performed in the presence of 5 mM or 15 mM basolateral glucose to investigate how changes in blood glucose, such as those seen in CFRD, affects luminal Ps. aeruginosa growth. Calu-3 cell monolayers were used to evaluate the potential importance of glucose on Ps. aeruginosa growth, in comparison to other hallmarks of the CF ASL, namely mucus hyperviscosity and impaired CFTR-dependent fluid secretions. We show that elevation of basolateral glucose promotes the apical growth of Ps. aeruginosa on CF airway epithelial monolayers more than non-CF monolayers. Ps. aeruginosa secretions elicited more glucose flux across CF airway epithelial monolayers compared to non-CF monolayers which we propose increases glucose availability in ASL for bacterial growth. In addition, elevating basolateral glucose increased Ps. aeruginosa growth over and above any CFTR-dependent effects and the presence or absence of mucus in Calu-3 airway epithelia-bacteria co-cultures. Together these studies highlight the importance of glucose as an additional factor in promoting Ps. aeruginosa growth and respiratory infection in CF disease

CK2 is a key regulator of SLC4A2-mediated Cl-/HCO3 (-) exchange in human airway epithelia

Transepithelial bicarbonate secretion by human airway submucosal glands and surface epithelial cells is crucial to maintain the pH-sensitive innate defence mechanisms of the lung. cAMP agonists stimulate HCO3 (-) secretion via coordinated increases in basolateral HCO3 (-) influx and accumulation, as well as CFTR-dependent HCO3 (-) efflux at the luminal membrane of airway epithelial cells. Here, we investigated the regulation of a basolateral located, DIDS-sensitive, Cl-/HCO3 (-) exchanger, anion exchanger 2 (AE2; SLC4A2) which is postulated to act as an acid loader, and therefore potential regulator of HCO3 (-) secretion, in human airway epithelial cells. Using intracellular pH measurements performed on Calu-3 cells, we demonstrate that the activity of the basolateral Cl-/HCO3 (-) exchanger was significantly downregulated by cAMP agonists, via a PKA-independent mechanism and also required Ca2+ and calmodulin under resting conditions. AE2 contains potential phosphorylation sites by a calmodulin substrate, protein kinase CK2, and we demonstrated that AE2 activity was reduced in the presence of CK2 inhibition. Moreover, CK2 inhibition abolished the activity of AE2 in primary human nasal epithelia. Studies performed on mouse AE2 transfected into HEK-293T cells confirmed almost identical Ca2+/calmodulin and CK2 regulation to that observed in Calu-3 and primary human nasal cells. Furthermore, mouse AE2 activity was reduced by genetic knockout of CK2, an effect which was rescued by exogenous CK2 expression. Together, these findings are the first to demonstrate that CK2 is a key regulator of Cl--dependent HCO3 (-) export at the serosal membrane of human airway epithelial cells

Recombinant Acid Ceramidase Reduces Inflammation and Infection in Cystic Fibrosis.

Rationale: In cystic fibrosis the major cause of morbidity and mortality is lung disease characterized by inflammation and infection. The influence of sphingolipid metabolism is poorly understood with a lack of studies using human airway model systems. Objectives: To investigate sphingolipid metabolism in cystic fibrosis and the effects of treatment with recombinant human acid ceramidase on inflammation and infection. Methods: Sphingolipids were measured using mass spectrometry in fully-differentiated cultures of primary human airway epithelial cells and co-cultures with Pseudomonas aeruginosa. In situ activity assays, Western blotting and quantitative polymerase chain reaction were used to investigate function and expression of ceramidase and sphingomyelinase. Effects of treatment with recombinant human acid ceramidase on sphingolipid profile and inflammatory mediator production were assessed in cell cultures and murine models. Measurements and Main Results: Ceramide is increased in cystic fibrosis airway epithelium due to differential function of enzymes regulating sphingolipid metabolism. Sphingosine, a metabolite of ceramide with antimicrobial properties, is not upregulated in response to Pseudomonas aeruginosa by cystic fibrosis airway epithelia. Tumor necrosis factor receptor 1 is increased in the apical membrane of cystic fibrosis epithelia and activates NF-κB signaling, generating inflammation. Treatment with recombinant human acid ceramidase, to decrease ceramide, reduced both inflammatory mediator production and susceptibility to infection. Conclusions: Sphingolipid metabolism is altered in airway epithelial cells cultured from people with cystic fibrosis. Treatment with recombinant acid ceramidase ameliorates the two pivotal features of cystic fibrosis lung disease, inflammation and infection, and thus represents a therapeutic approach worthy of further exploration. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Characterisation of eppin function: expression and activity in the lung

Eppin is a serine protease inhibitor expressed in male reproductive tissues. In this study we have demonstrated novel sites of eppin expression in myeloid and epithelial cell lines with further confirmation in primary myeloid cell types. Using immunohistochemistry and Western blotting, eppin was detected in the lungs of patients with Acute Respiratory Distress Syndrome and Cystic Fibrosis lung disease. Expression of eppin in monocytic cells was unaffected by stimulation with TLR agonists, cytokine stimulation and hormone receptor agonist stimulation. However, upregulated expression and secretion of eppin was observed following treatment of monocytes with epidermal growth factor (EGF). Incubation of recombinant eppin with monocytic cells resulted in significant inhibition of lipopolysaccharide (LPS)-induced chemokine production. Furthermore, eppin inhibited LPS- induced NF-κB activation by a mechanism which involved accumulation of phosphorylated IκBα. In an in vivo model of lung inflammation induced by LPS, eppin administration resulted in decreased recruitment of neutrophils to the lung with a concomitant reduction in the levels of the neutrophil chemokine MIP-2. Overall, these results suggest a role for eppin outside of the reproductive tract and that eppin may have a role in the innate immuneresponse in the lung

Tracheostomy in children is associated with neutrophilic airway inflammation

Background Tracheostomies in children are associated with significant morbidity, poor quality of life, excess healthcare costs and excess mortality. The underlying mechanisms facilitating adverse respiratory outcomes in tracheostomised children are poorly understood. We aimed to characterise airway host defence in tracheostomised children using serial molecular analyses. Methods Tracheal aspirates, tracheal cytology brushings and nasal swabs were prospectively collected from children with a tracheostomy and controls. Transcriptomic, proteomic and metabolomic methods were applied to characterise the impact of tracheostomy on host immune response and the airway microbiome. Results Children followed up serially from the time of tracheostomy up to 3 months postprocedure (n=9) were studied. A further cohort of children with a long-term tracheostomy were also enrolled (n=24). Controls (n=13) comprised children without a tracheostomy undergoing bronchoscopy. Long-term tracheostomy was associated with airway neutrophilic inflammation, superoxide production and evidence of proteolysis when compared with controls. Reduced airway microbial diversity was established pre-tracheostomy and sustained thereafter. Conclusions Long-term childhood tracheostomy is associated with a inflammatory tracheal phenotype characterised by neutrophilic inflammation and the ongoing presence of potential respiratory pathogens. These findings suggest neutrophil recruitment and activation as potential exploratory targets in seeking to prevent recurrent airway complications in this vulnerable group of patients