Project description:Pseudomonas aeruginosa airway infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. In vitro models that closely mimic CF sputum are needed to improve understanding of the pathobiology of P. aeruginosa in the CF airway. We developed an artificial sputum medium (ASMDM) that more closely resembles the composition of CF sputum than current media. In order to validate the utility of ASMDM, we used GeneChip microarrays to compare expression data of P. aeruginosa UCBPP-PA14 (PA14) in ASMDM with published data for this strain grown under the same conditions in an artificial medium containing 10% (v/v) CF sputum. Thirty-seven of 39 nutrition-related genes were differentially expressed in the same manner in both media. However, 24 quorum-sensing (QS) genes, 23 Type III secretion system and several anaerobic respiration genes were more highly expressed in ASMDM than in sputum-containing medium. When grown to stationary phase in ASMDM, PA14 differentially expressed about 50 biologically significant genes compared to stationary phase growth in Luria Broth; genes involved in iron acquisition (pfeA, fepC) and in assimilatory nitrate reduction (nasC, nirD) were upregulated, while 24 QS genes, including the regulator rhlR, lasA, rsaL, aprADEI and phenazine genes phzC2DD2EG2 were downregulated. Downregulation of QS-regulated virulence genes has been noted in chronic P. aeruginosa infection. ASMDM thus appears highly suitable for studies on gene expression of (i) P. aeruginosa strains from acutely and chronically infected CF patients and (ii) established biofilms that are a hallmark of advanced CF lung disease.
Project description:Lung disease is the main cause of morbidity and mortality in cystic fibrosis (CF), and involves chronic infection by a destructive microbiota and perturbed innate and adaptive immune responses. Tissue damage is considered to be mediated mostly by proteases, but other bacterial and host factors may also play a role. To determine the presence of potentially injurious proteins we employed semi-quantitative Multidimensional Protein Identification Technology to identify sputum cellular proteins with consistently altered expression in CF compared to healthy controls. Ingenuity Pathway Analysis, Gene Ontology functions, protein abundance and correlation with lung function were used to infer their clinical significance. The CF proteome exhibited differential expression of proteins relating to Rho family small GTPase activity, immune cell movement and activation, generation of reactive oxygen species and dysregulation of cell death and proliferation. Compositional breakdown established neutrophil extracellular trap proteins as the consistently most abundant cellular proteins detected, while a further 13 biologically relevant proteins were found to correlate negatively with lung function. These findings expand the current understanding of the mechanisms underlying CF lung disease and identify sputum cell proteins which might be useful as markers of disease status, prognostic indicators, stratification determinants for treatment prescription or as therapeutic targets.
Project description:The study aimed to compare the gene expression profiles at a single cell level in Sputum cells between patients with cystic fibrosis (CF) and disease controls (CTRL).
Project description:Pseudomonas aeruginosa airway infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. In vitro models that closely mimic CF sputum are needed to improve understanding of the pathobiology of P. aeruginosa in the CF airway. We developed an artificial sputum medium (ASMDM) that more closely resembles the composition of CF sputum than current media. In order to validate the utility of ASMDM, we used GeneChip microarrays to compare expression data of P. aeruginosa UCBPP-PA14 (PA14) in ASMDM with published data for this strain grown under the same conditions in an artificial medium containing 10% (v/v) CF sputum. Thirty-seven of 39 nutrition-related genes were differentially expressed in the same manner in both media. However, 24 quorum-sensing (QS) genes, 23 Type III secretion system and several anaerobic respiration genes were more highly expressed in ASMDM than in sputum-containing medium. When grown to stationary phase in ASMDM, PA14 differentially expressed about 50 biologically significant genes compared to stationary phase growth in Luria Broth; genes involved in iron acquisition (pfeA, fepC) and in assimilatory nitrate reduction (nasC, nirD) were upregulated, while 24 QS genes, including the regulator rhlR, lasA, rsaL, aprADEI and phenazine genes phzC2DD2EG2 were downregulated. Downregulation of QS-regulated virulence genes has been noted in chronic P. aeruginosa infection. ASMDM thus appears highly suitable for studies on gene expression of (i) P. aeruginosa strains from acutely and chronically infected CF patients and (ii) established biofilms that are a hallmark of advanced CF lung disease. PA14 was grown in four different ways: 1. Logarithmic growth for early gene expression Cells were grown in MOPS-Glucose and separately in ASMDM. The average of two biological duplicates in each case was compared to the other to determine differential gene expression. 2. Stationary phase growth for gene expression Cells were grown in Luria Broth and separately in ASMDM. The average of two biological duplicates in each case was compared to the other to determine differential gene expression.
Project description:The PANarray design (GPL13324) contains the genes of eight P. aeruginosa genomes in non-redundant format, thus allowing identification of expression of non-PAO1 and other P. aeruginosa genes. For the series GSE28152, isogenic isolates were sequentially collected from two cystic fibrosis (CF) patients several years apart. The isolates had not been eradicated in the meantime and represent persister strains. One was an Australian Epidemic Strain-1 isolate and the other a non-epidemic strain. Strains were cultured in an artificial sputum medium (ASMDM) closely resembling CF sputum.
Project description:Rationale: We recently demonstrated that the triple combination CFTR modulator therapy elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves lung ventilation and airway mucus plugging determined by multiple-breath washout and magnetic resonance imaging in CF patients with at least one F508del allele. However, effects of ELX/TEZ/IVA on viscoelastic properties of airway mucus, chronic airway infection and inflammation have not been studied. Objectives: To examine the effects of ELX/TEZ/IVA on airway mucus rheology, microbiome and inflammation in CF patients with one or two F508del alleles aged 12 years and older. Methods: In this prospective observational study, we determined sputum rheology, microbiome, inflammation markers and proteome before and 1, 3 and 12 months after initiation of ELX/TEZ/IVA. Measurements and Main Results: CF patients with at least one F508del allele and healthy controls were enrolled in this study. ELX/TEZ/IVA improved the elastic and viscous modulus of CF sputum. Further, ELX/TEZ/IVA improved the microbiome α-diversity and decreased the relative abundance of Pseudomonas aeruginosa (P<0.05) in CF sputum. ELX/TEZ/IVA also reduced IL-8 and free NE activity, and shifted the CF sputum proteome towards healthy. Conclusions: Our data demonstrate that ELX/TEZ/IVA improves sputum viscoelastic properties, chronic airway infection and inflammation in CF patients with at least one F508del allele, however, without reaching levels close to healthy.
Project description:Cystic fibrosis (CF) is an inherited, multi-system disease caused by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, a ubiquitous ion channel important for epithelial hydration. A direct consequence of this dysfunction is impaired mucociliary clearance, chronic airway infection and a persistent neutrophilic inflammatory response that results in progressive loss of lung function, development of respiratory failure and premature death. Partial restoration of CFTR function is now possible for most CF patients through mutation specific CFTR modulators. Ivacaftor monotherapy produces significant clinical improvement in CF patients with the G511D mutation. Dual therapy, combining ivacaftor with lumacaftor or tezacaftor, results in modest clinical improvements in patients homozygous for F508del. More recently, triple therapy with elexacaftor/tezacaftor/ivacaftor (ETI) has led to dramatic improvements in lung function and quality of life in patients homozygous and heterozygous for F508del. Sputum proteomics is a powerful research technique capable of identifying important airway disease mechanisms by interrogating the proteome, an entire set of proteins within biological samples. It has confirmed the central role of neutrophilic immune dysregulation in CF and non-CF bronchiectasis, particularly involving the release of antimicrobial proteins and neutrophil-extracellular traps (NETs), and through impaired anti-inflammatory mechanisms. These processes produce distinct molecular signatures within the sputum proteome that become increasingly abnormal with chronic airway infection and progressive lung disease severity. In CF patients, airway and systemic inflammatory cytokines potentially related to these signatures reduce with the various forms of CFTR modulation. To date, no studies of ETI therapy in CF lung disease have assessed large-scale change in protein expression using untargeted proteomics. We hypothesised that ETI therapy would shift the sputum proteome toward health, potentially normalising airway biology in people with CF. The objectives of this study were to investigate changes in the CF sputum proteome with the introduction of ETI, correlate these with changes in clinical markers of disease severity, and make comparisons with the sputum proteome in healthy controls and in repeat samples from CF patients not suitable for ETI therapy. We also explored which molecular pathways associated with CF lung disease did not change with ETI.
Project description:We characterized the transcriptional responses of three S. maltophilia strains during exposure to synthetic CF sputum media (SCFM2) to gain insight into how this organism interacts with the host in the CF lung. These efforts led to the identification of 881 transcripts differentially expressed by all three strains, many of which reflect different metabolic pathways used by S. maltophilia in sputum, and altered stress responses. The latter correlated with increased resistance to peroxide exposure after pre-growth in SCFM2. We also compared the SCFM2 transcriptomes of two S. maltophilia CF isolates with the SCFM2 transcriptome of the acute infection model strain, S. maltophilia K279A, allowing us to identify CF isolate-specific signatures in differential gene expression that may be suggestive of adaptation to the CF lung. Each strain also possessed genes not shared by the other two and here we show that expression of some of the accessory genes in each strain are changed in response to SCFM2. Collectively, this work details the response of S. maltophilia to the CF lung environment, identifying potential survival strategies and metabolic pathways used by S. maltophilia during infections.