Crystal structure of Pseudomonas aeruginosa RsaL bound to promoter DNA reaffirms its role as a global regulator involved in quorum-sensing
Ontology highlight
ABSTRACT:
ORGANISM(S): Pseudomonas aeruginosa
PROVIDER: GSE87157 | GEO | 2016/12/20
SECONDARY ACCESSION(S): PRJNA343734
REPOSITORIES: GEO
Similar Datasets
Project description:Virulence factor production and the development of biofilms in Pseudomonas aeruginosa have been shown to be regulated by two hierarchically organised quorum sensing (QS) systems via small acyl-homoserine lactone (AHL) signal molecules. Recently, a third bacterial signal molecule, the Pseudomonas quinolone signal (PQS), has been identified, which positively regulates a subset of genes dependent on the QS systems. To further dissect the various independent regulation levels for many QS induced genes and to evaluate the impact of PQS on the QS circuitry, we performed a transcriptome analysis of PAO1 cultures supplemented with PQS. The global transcriptional profile in response to PQS revealed a marked up-regulation of genes belonging to the tightly interdependent functional groups of iron acquisition and oxidative stress response. Remarkably, not only most of the differentially regulated genes but also the induction of a lacZ transcriptional fusion of rhlR could be traced back to a iron chelating effect of PQS. Nevertheless, although iron deficiency per se induced rhlR, there seems to be PQS specific effects that are independent of the PQS effect on P. aeruginosa iron homeostasis Keywords: PQS response
2006-12-12 | GSE3836 | GEO
Project description:Virulence factor production and the development of biofilms in Pseudomonas aeruginosa have been shown to be regulated by two hierarchically organised quorum sensing (QS) systems via small acyl-homoserine lactone (AHL) signal molecules. Recently, a third bacterial signal molecule, the Pseudomonas quinolone signal (PQS), has been identified, which positively regulates a subset of genes dependent on the QS systems. To further dissect the various independent regulation levels for many QS induced genes and to evaluate the impact of PQS on the QS circuitry, we performed a transcriptome analysis of PAO1 cultures supplemented with PQS. The global transcriptional profile in response to PQS revealed a marked up-regulation of genes belonging to the tightly interdependent functional groups of iron acquisition and oxidative stress response. Remarkably, not only most of the differentially regulated genes but also the induction of a lacZ transcriptional fusion of rhlR could be traced back to a iron chelating effect of PQS. Nevertheless, although iron deficiency per se induced rhlR, there seems to be PQS specific effects that are independent of the PQS effect on P. aeruginosa iron homeostasis Experiment Overall Design: For RNA extraction bacteria were harvested at early logarithmic, late logarithmic and stationary phase of growth. Three independent cultures of PQS-treated and untreated PAO1 each were pooled and the RNA was immediately stabilized with RNAprotect Bacteria Reagent (Qiagen, Valencia, CA). RNA was isolated using the RNeasy kit (Qiagen), treated with DNaseI (Roche) for 30 min at 37M-BM-0C and re-purified with the RNeasy spin column. The subsequent steps of cDNA generation and Biotin-ddUTP terminal labelling were performed as described in the manufacturerM-bM-^@M-^Ys instructions for the P. aeruginosa GeneChipM-CM-^R. Fragmented and labelled cDNA was hybridised to a GeneChip at 50 M-BM-0C for 16 h. The washing steps, staining and scanning of the microarrays were performed using the Affymetrix GeneChip system. Data analysis was performed using the Affymetrix Microarray Suite Software 5.0 with Affymetrix default parameters. As expression analysis was performed in duplicate, a total of two GeneChips per culture condition was scanned at 570 nm, 3 M-BM-5m resolution in an Affymetrix GeneChip scanner. The signals were multiplied by a scaling factor to make the average signal for all the arrays equivalent. The data were imported into a Microsoft Access database capable of searching for genes, which were found in all four pairings defined by the Affymetrix Microarray Suite Software as having significant changes in their signal intensities. Data were combined with the latest annotation from the website of the P. aeruginosa PAO1 sequence and the community annotation project provided at www.pseudomonas.com.
2008-11-07 | E-GEOD-3836 | biostudies-arrayexpress
Project description:The gene PA2384 in Pseudomonas aeruginosa PAO1, annotated originally as unknown function, has been previously shown to be dramatically responsive to iron limitation. In the present study, PA2384 is shown by bioinformatics analysis to have a weak similarity to the N-termini DNA binding domain of fur, a well-known ferric uptake regulator. To experimentally investigate the function of PA2384 P. aeruginosa PAO1 recombinant (pUCP20::PA2384) overexpressing PA2384 and PA2384 knock-out mutant PAO1-23844 are constructed and studied. Physiological characterization in a carefully controlled cultivation system shows that the knockout strain needed a longer lag phase to grow and exhibited a significantly reduced production speed of siderophore (pyoverdine and pyochelin) in the stationary phase. Genome-scale transcriptional profiles at different growth stages are compared between the wild type and âPA2384 mutant grown under iron-limiting conditions. The expression of more than 350 genes is affected. Among them, seventy-one genes involved in iron uptake are significantly induced by PA2384. 102 quorum sensing (QS) dependent genes exhibited differential transcription. They include genes related to the biosynthesis of some important virulence factors such as pyocyanin, rhamnolipids and hydrogen cyanide. Transcription of genes responsible for the synthesis of Pseudomonas Quinolone Signal (PQS) is greatly advanced by the knockout of PA2384. We postulate that PA2384 affects QS via PQS. Furthermore, the knockout of PA2384 also results in altered expression of genes involved in electron transfer, central metabolism, phosphorus starvation and translation. It implies that PA2384 may affect more basic physiology than only respond to iron uptake and is a versatile global regulator in P. aeruginosa under iron starvation. Experiment Overall Design: mutant and wilde type biological replicates were analyzed at 3 timepoints
2007-09-21 | E-GEOD-2885 | biostudies-arrayexpress
Project description:Pseudomonas aeruginosa pathogenicity mainly relies on its ability to finely control the expression of virulence determinants via multiple quorum sensing (QS) systems. Despite the relevant role of the pqs QS system in controlling the expression of key virulence factors and biofilm formation in P. aeruginosa, our understanding of the molecular mechanisms governing this QS circuit, which employs 2-alkyl-4-quinolones (AQs) as signal molecules, is still preliminary, probably due to its complexity. Multiple genes are required for the synthesis of the primary AQs, 2-heptyl-4-hydroxyquinoline (HHQ), 2-heptyl-3-hydroxy-4-quinolone (PQS), and 2-heptyl-4-hydroxyquinoline N-oxide (HQNO). These include the pqsABCDE operon, required for the synthesis of HHQ, which in turn is oxidized to PQS via the action of the monooxygenase PqsH. The monooxygenase PqsL is required for HQNO synthesis together with the pqsABCD genes. The fifth gene of the pqsABCDE operon, pqsE, is also required for the production of major virulence factors and for biofilm formation, and exerts a homeostatic effect on AQs synthesis by repressing the transcription of the pqsABCDE operon. The pqs system is subject to positive autoregulation, with the PqsR regulator promoting pqsABCDE transcription upon binding to HHQ or PQS. However, the individual contributions and relative importance of HHQ, PQS, HQNO and PqsE to AQ-dependent signalling is not fully apparent, because of the overlapping and interdependent nature of the factors involved in this complex QS network. We used microarrays to detail the global response of a P. aeruginosa mutant strain unable to synthesise or convert AQs, and to express PqsE to exogenously provided AQs or IPTG (to induce pqsE expression).
2020-11-21 | GSE81364 | GEO
Project description:It has been proposed that the gastro-intestinal tract environment containing high levels of neuroendocrine hormones is important for gut-derived P. aeruginosa infections. In this study, we report that the hormone norepinephrine increases P. aeruginosa PA14 growth, virulence factor production, invasion of HCT-8 epithelial cells, and swimming motility in a concentration-dependent manner. Transcriptome analysis of P. aeruginosa exposed to 500 µM, but not 50 µM, norepinephrine for 7 h showed that genes involved in the regulation of the virulence determinants pyocyanin, elastase, and Pseudomonas quinolone signal (PQS, 2-heptyl-3-hydroxy-4-quinolone) were up-regulated. The production of rhamnolipids, which are also important in P. aeruginosa infections, was significantly decreased on semi-solid surfaces, but not in planktonic cultures, upon exposure to norepinephrine. Swarming motility, a phenotype that is directly influenced by rhamnolipids, was also decreased upon 500 µM norepinephrine exposure. The increase in the transcriptional activation of lasR, but not that of rhlR, suggest that the effects of norepinephrine are mediated primarily through the las quorum sensing pathway. Together, our data strongly suggests that norepinephrine can play an important role in gut-derived infections by increasing the pathogenicity of P. aeruginosa PA14.
2009-08-27 | GSE13326 | GEO
Project description:The gene PA2384 in Pseudomonas aeruginosa PAO1, annotated originally as unknown function, has been previously shown to be dramatically responsive to iron limitation. In the present study, PA2384 is shown by bioinformatics analysis to have a weak similarity to the N-termini DNA binding domain of fur, a well-known ferric uptake regulator. To experimentally investigate the function of PA2384 P. aeruginosa PAO1 recombinant (pUCP20::PA2384) overexpressing PA2384 and PA2384 knock-out mutant PAO1-23844 are constructed and studied. Physiological characterization in a carefully controlled cultivation system shows that the knockout strain needed a longer lag phase to grow and exhibited a significantly reduced production speed of siderophore (pyoverdine and pyochelin) in the stationary phase. Genome-scale transcriptional profiles at different growth stages are compared between the wild type and ∆PA2384 mutant grown under iron-limiting conditions. The expression of more than 350 genes is affected. Among them, seventy-one genes involved in iron uptake are significantly induced by PA2384. 102 quorum sensing (QS) dependent genes exhibited differential transcription. They include genes related to the biosynthesis of some important virulence factors such as pyocyanin, rhamnolipids and hydrogen cyanide. Transcription of genes responsible for the synthesis of Pseudomonas Quinolone Signal (PQS) is greatly advanced by the knockout of PA2384. We postulate that PA2384 affects QS via PQS. Furthermore, the knockout of PA2384 also results in altered expression of genes involved in electron transfer, central metabolism, phosphorus starvation and translation. It implies that PA2384 may affect more basic physiology than only respond to iron uptake and is a versatile global regulator in P. aeruginosa under iron starvation. Keywords: iron starvation, quorum sensing, time course
2005-09-07 | GSE2885 | GEO
Project description:To establish infections in human hosts, P. aeruginosa must overcome innate immune generated oxidative stress, such as the hypochlorous acid (HOCl) produced by neutrophils. We set out to find specific metabolomic biomarkers of oxidative stress and we developed a protocol for the metabolic profiling of P. aeruginosa cultures grown in the presence of different oxidants using a novel ionisation technique for mass spectrometry, laser-desorption rapid evaporative ionisation mass spectrometry (LD-REIMS). We demonstrate the ability of LD-REIMS to classify samples as untreated or treated with a specific oxidant with 100 % accuracy and identified a panel of 54 metabolites with significantly altered concentrations after exposure to one or more of the oxidants. Key metabolic changes were conserved in P. aeruginosa clinical strains isolated from patients with cystic fibrosis lung infections. These data demonstrate that HOCl stress impacted the Pseudomonas Quinolone Signal (PQS) quorum sensing system. Ten 2-alkyl-4-quinolones (AHQs) associated with the PQS system were significantly lower in concentration in HOCl-stressed P. aeruginosa cultures, including 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), the most active signal molecule of the PQS system. The PQS system regulates the production of virulence factors, including pyocyanin and elastase, and their levels were markedly affected by HOCl stress. No pyocyanin was detectable and elastase concentrations were significantly reduced in cultures grown with sub-lethal concentrations of HOCl, suggesting that this neutrophil-derived oxidant may disrupt the ability of P. aeruginosa to establish infections through interference with production of PQS-associated virulence factors.
2023-10-06 | MSV000093056 | MassIVE
Project description:The common opportunistic human pathogen Pseudomonas aeruginosa employs quorum sensing QS to regulate a large set of genes involved in virulence and host-pathogen interactions. The Las circuit positioned on the top of the QS hierarchy in P. aeruginosa, makes use of N-acyl-L-homoserine lactones (AHL) as signal molecules, like N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C12-HSL). Here, a quantitative proteomic approach was used to study the effect of natural 3O-C12-HSL and four AHL analogues on the expression and excretion of QS-regulated extracellular proteins. Treatment with AHL compounds resulted in significant difference in appearance of the 3O-C12-HSL-responsive reference proteins related to QS communication and virulence, i.e., a distinct activity as QS modulators. In summary, 3O-C12-HSL has a profound effect on extracellular proteome involved in the pathogenicity of P. aeruginosa, and the four AHL analogues have achieved a distinct inhibitory effect on the extracellular proteome.
2023-10-06 | PXD045881 | Pride
Project description:The opportunistic pathogen Pseudomonas aeruginosa has complex quorum sensing (QS) circuitry, which involves two acylhomoserine lactone (AHL) systems, the LasI AHL synthase and LasR AHL-dependent transcriptional activator system and the RhlI AHL synthase-RhlR AHL-responsive transcriptional activator. There is also a quinoline signaling system (the Pseudomonas quinolone signal, PQS, system). Although there is a core set of genes regulated by the AHL circuits, there is substantial strain-to-strain variation in the non-core QS regulated genes. Reductive evolution of the QS regulon, and variation in specific genes activated by QS occurs in laboratory evolution experiments with the model strain PAO1. We used a transcriptomics approach to test the hypothesis that reductive evolution in the PAO1 QS regulon can in large part be explained by a simple null mutation in pqsR, the gene encoding the transcriptional activator of the pqs operon. We found that PqsR had very little influence on the AHL QS regulon. This was a surprising finding because the last gene in the PqsR-dependent pqs operon, pqsE, codes for a protein, which physically interacts with RhlR and this interaction is required for full RhlR-dependent activation of some genes. We used comparative transcriptomics to examine the influence of a pqsE mutation on the QS regulon and identified only three transcripts, which were strictly dependent on PqsE. By using reporter constructs we showed that the PqsE influence on other genes was dependent on experimental conditions and we have gained some insight about those conditions. This work adds to our understanding of the plasticity of the P. aeruginosa QS regulon and to the role PqsE plays in RhlR-dependent gene activation.
2024-03-17 | GSE261453 | GEO
Project description:The human opportunistic pathogen Pseudomonas aeruginosa orchestrates the expression of many genes in a cell density-dependent manner by using a molecular communication system referred to as quorum sensing (QS). This bacterium uses an intricate network of regulators and QS molecules known as autoinducers. Among these autoinducers are two acyl-homoserine lactones (AHL) involved in QS circuits which modulate virulence factors production, biofilm formation, and antimicrobial sensitivity. Disrupting QS, a strategy referred to as quorum quenching (QQ), is a promising approach to modulate virulence while not directly challenging bacterial survival. For P. aeruginosa, QQ can be achieved using exogenous AHL-degrading lactonases. However, the importance of enzyme specificity on quenching efficacy has never been investigated. Here, we used two lactonases both targeting the signal molecules N-(3-oxododecanoyl)-L-Homoserine lactone (3-oxo-C12 HSL) and butyryl-homoserine lactone (C4 HSL) albeit with different efficacy on C4 HSL. Interestingly, both lactonases similarly decreased the concentrations of AHL and comparably impacted the expression of AHL-based circuits. Conversely, strong variations were observed in Pseudomonas Quinolone Signal (PQS) regulation. Both lactonases were then found to decrease virulence factors production and biofilm formation in vitro, albeit with different efficiencies. Unexpectedly, only the lactonase with substrate preference for 3-oxo-C12 HSL was able to inhibit P. aeruginosa pathogenicity in vivo in an amoeba infection model. Similarly, large variations between lactonases were observed in proteins involved in antibiotic resistance, biofilm formation, virulence and diverse cellular mechanisms. This global analysis provides the first evidence that QQ enzyme specificity is crucial to modulate QS-associated behavior in P. aeruginosa PA14.
2020-05-27 | PXD017421 | Pride