Importance of superoxide dismutases A and M for protection of Staphylococcus aureus in the oxidative stressful environment of the cystic fibrosis airways
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ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE131862 | GEO | 2020/01/27
REPOSITORIES: GEO
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Project description:Staphylococcus aureus is one of the first and most prevalent pathogens cultured from the airways of cystic fibrosis (CF) patients, which can persist there for extended periods. Airway infections in CF patients are characterized by a strong inflammatory response of highly recruited neutrophils. One killing mechanism of neutrophils is the formation of neutrophil extracellular traps (NETs), which capture and eradicate bacteria by extracellular fibers of neutrophil chromatin decorated with antimicrobial granule proteins. S. aureus secretes nuclease, which can degrade NETs. We hypothesized, that S. aureus adapts to the airways of CF patients during persistent infection by escaping from NET-mediated killing via an increase of nuclease activity. Sputum samples of CF patients with chronic S. aureus infection were visualized by confocal microscopy after immuno-fluorescence staining for NET-specific markers, S. aureus bacteria and overall DNA structures. Nuclease activity was analyzed in sequential isogenic long persisting S. aureus isolates, as confirmed by whole genome sequencing, from an individual CF patient using a FRET-based nuclease activity assay. Additionally, some of these isolates were selected and analyzed by qRT-PCR to determine the expression of nuc1 and regulators of interest. NET-killing assays were performed with clinical S. aureus isolates to evaluate killing and bacterial survival depending on nuclease activity. To confirm the role of nuclease during NET-mediated killing, a clinical isolate with low nuclease activity was transformed with a nuclease expression vector (pCM28nuc). Furthermore, two sputa from an individual CF patient were subjected to RNA-sequence analysis to evaluate the activity of nuclease in vivo. In sputa, S. aureus was associated to extracellular DNA structures. Nuclease activity in clinical S. aureus isolates increased in a time-and phenotype-dependent manner. In the clinical isolates, the expression of nuc1 was inversely correlated to the activity of agr and was independent of saeS. NET-mediated killing was significantly higher in S. aureus isolates with low compared to isolates with high nuclease activity. Importantly, transformation of the clinical isolate with low nuclease activity with pCM28nuc conferred protection against NET-mediated killing confirming the beneficial role of nuclease for protection against NETs. Also, nuclease expression in in vivo sputa was high, which underlines the important role of nuclease within the highly inflamed CF airways. In conclusion, our data show that S. aureus adapts to the neutrophil-rich environment of CF airways with increasing nuclease expression most likely to avoid NET-killing during long-term persistence.
2019-11-01 | GSE139662 | GEO
Project description:Chronic airway infection with P. aeruginosa (PA) is a hallmark of cystic fibrosis (CF) disease. The mechanisms producing PA persistence in CF therapies remain poorly understood. To gain insight on PA physiology in patient airways and better understand how in vivo bacterial functioning differs from in vitro conditions, we investigated the in vivo proteomes of PA in 35 sputum samples from 11 CF patients. We developed a novel bacterial-enrichment method enabling improved identification of PA proteome with CF sputum samples. The in vivo PA proteomes were compared with the proteomes of ex vivo-grown PA populations from the same patient sample. We detected 1528 PA proteins (encoded by 1458 core genes and 70 accessory genes) that were expressed in CF airways, of which 1178 proteins were commonly identified with the ex vivo-grown PA populations. Label-free quantitation and proteome comparison revealed the in vivo up-regulation of siderophore TonB-dependent receptors, remodeling in central carbon metabolism including glyoxylate cycle and lactate utilization, and alginate overproduction. Knowledge of these in vivo proteome differences or others derived using the presented methodology could lead to future treatment strategies aimed at altering PA physiology in vivo to compromise infectivity or improve antibiotic efficacy.
2019-05-09 | PXD011792 | Pride
Project description:Cystic Fibrosis lung disease progresses by a combination of accelerated airways inflammation and bacterial colonization and infection. Airways inflammation in CF is predominantly neutrophilic and complicates airway clearance therapies through cellular debris, excessive DNA, excessive and viscous mucous, and high concentrations of neutrophils,Il-8 and related cytokines liberated along the NFkB signaling pathway. We conducted a single site, randomized, double blind, placebo-controlled, proof-of-concept trial in which we evaluated the effects of 28 days of two dose levels (0.05 mg and 0.10 mg daily) of an older cardiac glycoside, digitoxin, as compared with placebo, on inflammatory markers in induced sputum obtained from 24 subjects with mild to moderate CF lung disease. Nasal epithelial cells from 23 subjects were analyzed for microarray analysis. CF patients 18 to 45 years old, any genotype combination, were eligible. The primary objective was to measure the effects of digitoxin on IL-8 and neutrophil counts in induced sputum. Secondary objectives were to measure: 1) the pharmacokinetics of digitoxin in serum in stable CF patients, 2) safety indices, including ECG changes and sputum microbiology, in stable CF patients, 3) the effect of digitoxin on gene expression in nasal epithelial cells of stable CF patients and 4) quality of life scores using the CFQ-R©. As expected, it took several weeks to achieve a detectable serum level of digitoxin in CF. Digitoxin showed a trend towards reduction in sputum free neutrophil elastase and neutrophil counts, but was not associated with a reduction in sputum Il-8. Digitoxin did not dampen sputum inflammation as measured by primary and secondary outcome measures over the 28 day study period. However the patient groups receiving placebo and 50 micro gram digitoxin daily fell into similar patterns which were distinctly different from the patient group taking 100 micro gram digitoxin. The mRNAs encoding chemokine/cytokine or cell surface receptors in immune cells were decreased in nasal epithelial cells at the higher dose, leading to pathway mediated reductions in Il-8, Il-6, lung epithelial inflammation, neutrophil recruitment and mucus hypersecretion. It is possible that a longer treatment period would be necessary to detect a meaningful, dose- dependent change in sputum indices of inflammation in CF. Importantly, there were no safety issues over the course of the study
2017-01-09 | GSE76347 | GEO
Project description:Background: Chronic lung infection of cystic fibrosis (CF) patients by Staphylococcus aureus is a well-established epidemiological fact. Indeed, S. aureus is the most commonly identified pathogen in the lungs of CF patients. Strikingly the molecular mechanisms underlying S. aureus persistency are not understood. Methods: To gain insights into S. aureus adaptation to CF lungs, we selected pairs of sequential S. aureus isolates from 3 patients with CF and from one patient with non-CF chronic lung disease. We used a combination of genomic, proteomic and metabolomic approaches with functional assays for in-depth characterization of S. aureus long-term persistence during chronic lung infection. Results: For the first time, we show that late S. aureus isolates from CF patients have an increased ability for intracellular survival in CFBE-F508del cells compared to ancestral early isolates. Importantly, the increased ability to persist intracellularly was confirmed for S. aureus isolates within the own patient F508del epithelial cells. An increased ability to form biofilm was also demonstrated. Furthermore, to explain observed phenotypic adaptations, we identified the underlying genetic modifications inducing altered protein expression profiles and notable metabolic changes. These modifications affect several metabolic pathways (e.g., pantothenate and fatty acids) and virulence regulators (encoded by agr and sae loci) that could constitute therapeutic targets. Conclusions: Our results strongly suggest that the intracellular environment might constitute an important niche of persistence and relapse necessitating adapted antibiotic treatments.
2021-03-29 | PXD011281 | Pride
Project description:[1] Transcription profiling of one Burkholderia cenocepacia clinical isolate, J2315, versus a soil isolate, HI2424, in conditions mimicking CF sputum [2] Transcription profiling of Burkholderia cenocepacia isolates J2315 and HI2424 in media mimicking CF sputum or the soil environment
2009-12-01 | GSE15817 | GEO
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.
2010-05-31 | GSE18594 | GEO
Project description:Hallmarks of cystic fibrosis (CF) are increased viscosity of mucus and impaired mucociliary clearance within the airways due to mutations of the cystic fibrosis conductance regulator gene. This paves the way for the colonization by microbial pathogens and the concomitant establishment of chronic infections leading to lung tissue damage, reduced lung function, and to decreased life expectancy. Although microbial infections play a key role during disease progression, only a few studies investigated the pathophysiology of the microbial community in vivo so far. Moreover, no CF study so far applied metaproteomics, a powerful approach to unravel molecular mechanisms of microbial infection, mainly reasoned due to (I) the challenging processability of inhomogeneous, viscous, slimy sputum, and (II) the high number of human proteins masking comparably low abundant microbial proteins. Consequently, we developed a reliable, reproducible and widely applicable protocol for sputum processing, microbial enrichment, and subsequent metaproteomics analyses with a focus on microbial pathogens overcoming the aforementioned challenges. Metaproteomics data were complemented and validated by 16S sequencing, metabolomic as well as microscopic analyses. In total, we processed 21 CF sputum samples and selected three for detailed metaproteome analysis. The number of bacterial proteins/protein groups increased from 199-425 to 392-868. Moreover, our data suggest that the arginine deiminase pathway and multiple proteases and peptidases identified from various bacterial genera are so far underappreciated in their contribution to the CF pathophysiology. By providing a standardized and effective protocol for sputum processing and microbial enrichment, our study represents an important basis for future studies investigating the physiology of microbial pathogens in CF in vivo – an important prerequisite for the development of novel antimicrobial therapies against mucoviscidosis.
2021-11-03 | PXD025134 | Pride
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.
2010-06-08 | E-GEOD-18594 | biostudies-arrayexpress
Project description:One of the hallmarks of Pseudomonas aeruginosa cystic fibrosis (CF) infection is very high-cell-density (HCD) replication in the lung, allowing this bacterium to induce virulence controlled by HCD quorum-sensing systems. However, the nutrient sources sustaining HCD replication in this chronic infection is largely unknown. Hence, understanding the nutrient factors contributing to HCD in the CF lung will yield new insights into the 'metabolic pathogenicity' and potential treatment of CF infections caused by P. aeruginosa. Herein, we performed microarray studies of P. aeruginosa directly isolated from the CF lung to demonstrate its metabolic capability and virulence in vivo. Our in vivo microarray data, confirmed by real-time reverse-transcription-PCR, indicated P. aeruginosa expressed several genes for virulence, drug-resistance, and utilization of multiple nutrient sources (lung surfactant lipids and amino acids) contributing to HCD replication. The data also indicates deregulation of several pathways, suggesting in vivo evolution by deregulation of a large portion of the transcriptome during chronic CF infection. To our knowledge, this is the first in vivo transcriptome of P. aeruginosa in a natural CF infection, and it indicates several important aspects of pathogenesis, drug-resistance, and nutrient-utilization never before observed in vivo. Experiment Overall Design: The purpose of the experiment was to observe which genes are upregulated in P. aeruginosa during chronic CF lung infection as compared to PAO1. All in vitro studies were grown in 1x M9 minimal media supplemented with 20 mM citrate and grown to mid-log phase prior to RNA isolation. The in vivo RNA was isolated directly from CF sputum samples after TRIzol treatment. Each in vitro sample (both for PAO1 and the CF sputum pool isolate) were processed individually and in triplicate. Two in vivo isolations from sputum were conducted from the same patient but two different sputum samples. After isolation of total RNA, samples were processed for microarrays (i.e. cDNA synthesis, fragmentation, labeling, etc) as recommended by Affymetrix, and processed on the GeneChip as recommended by Affymetrix.
2008-06-15 | E-GEOD-7704 | biostudies-arrayexpress
Project description:[1] Transcription profiling of one Burkholderia cenocepacia clinical isolate, J2315, versus a soil isolate, HI2424, in conditions mimicking CF sputum [2] Transcription profiling of Burkholderia cenocepacia isolates J2315 and HI2424 in media mimicking CF sputum or the soil environment [1] J2315 vs. HI2424 cells in the same condition. [2] Two-condition experiment. Biological replicates: 4 replicates.
2010-05-19 | E-GEOD-15817 | biostudies-arrayexpress