Mutations in the RUNX1 gene (RUNX1mut) have been established in myelodysplasia (MDS), de novo and secondary acute myeloid leukaemia (AML), and are in general associated with an unfavourable clinical outcome. Familial RUNX1 mutations are associated with familial thrombocytopenia and these patients have a predisposition to AML development. However, a number of studies have been performed so far in mice which might be distinct from the human hematopoietic system. Therefore we studied the cellular phenotypes, the RUNX1 binding pattern and expression profile induced by RUNX1mut in cord blood (CB) CD34+ cells and induced pluripotent stem cell (iPSC) and compared these findings to primary RUNX1mut AML's. Overall design: A total of nine samples were subject to RNA-Seq including RUNX1mut-transduced cord blood CD34 cells and time-course iPSCs.
RUNX1 mutations enhance self-renewal and block granulocytic differentiation in human in vitro models and primary AMLs.
Specimen part, Subject
View SamplesBiofilms are surface-adhered bacterial communities encased in an extracellular matrix composed of polysaccharides, proteins, and extracelluar (e)DNA, with eDNA being required for the formation and integrity of biofilms. Here we demonstrate that the spatial and temporal release of eDNA is regulated by BfmR, a regulator essential for Pseudomonas aeruginosa biofilm development. The expression of bfmR coincided with localized cell death and DNA release, with high eDNA concentrations localized to the outer part of microcolonies in the form of a ring and as a cap on small clusters. Additionally, eDNA release and cell lysis increased significantly following bfmR inactivation. Genome-wide transcriptional profiling indicated that bfmR was required for repression of genes associated with bacteriophage assembly and bacteriophage-mediated lysis. In order to determine which of these genes were directly regulated by BfmR, we utilized chromatin immunoprecipitation (ChIP) analysis to identify the promoter of PA0691, termed here phdA, encoding a previously undescribed homologue of the prevent-host-death (Phd) family of proteins. Lack of phdA expression coincided with impaired biofilm development, increased cell death and bacteriophage release, a phenotype comparable to bfmR. Expression of phdA in bfmR biofilms restored eDNA release, cell lysis, release of bacteriophages, and biofilm formation to wild type levels. Moreover, overexpression of phdA rendered P. aeruginosa resistant to lysis mediated by superinfective bacteriophage Pf4 which was only detected in biofilms. The expression of bfmR was stimulated by conditions resulting in membrane perturbation and cell lysis. Thus, we propose that BfmR regulates biofilm development by controlling bacteriophage-mediated lysis and thus, cell death and eDNA release, via PhdA.
The novel Pseudomonas aeruginosa two-component regulator BfmR controls bacteriophage-mediated lysis and DNA release during biofilm development through PhdA.
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View SamplesA hallmark of the biofilm architecture is the presence of microcolonies. However, little is known about the underlying mechanisms governing microcolony formation. In the human pathogen Pseudomonas aeruginosa, microcolony formation is dependent on the two-component regulator MifR, with mifR mutant biofilms exhibiting an overall thin structure lacking microcolonies, and overexpression of mifR resulting in hyper-microcolony formation. Here, we made use of the distinct MifR-dependent phenotypes to elucidate mechanisms associated with microcolony formation. Using global transcriptomic and proteomic approaches, we demonstrate that cells located within microcolonies experience stressful, oxygen limited, and energy starving conditions, as indicated by the activation of stress response mechanisms and anaerobic and fermentative processes, in particular pyruvate fermentation. Inactivation of genes involved in pyruvate utilization including uspK, acnA and ldhA abrogated microcolony formation in a manner similar to mifR inactivation. Moreover, depletion of pyruvate from the growth medium impaired biofilm and microcolony formation, while addition of pyruvate significantly increased microcolony formation. Addition of pyruvate partly restored microcolony formation in mifR biofilms. Moreover, addition of pyruvate to or expression of mifR in lactate dehydrogenase (ldhA) mutant biofilms did not restore microcolony formation. Consistent with the finding of denitrification genes not demonstrating distinct expression patterns in biofilms forming or lacking microcolonies, addition of nitrate did not alter microcolony formation. Our findings indicate the fermentative utilization of pyruvate to be a microcolony-specific adaptation to the oxygen limitation and energy starvation of the P. aeruginosa biofilm environment.
Microcolony formation by the opportunistic pathogen Pseudomonas aeruginosa requires pyruvate and pyruvate fermentation.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
RNA-stabilized whole blood samples but not peripheral blood mononuclear cells can be stored for prolonged time periods prior to transcriptome analysis.
Sex, Age, Specimen part, Time
View SamplesAnalysis of effect of long-term cryopreservation on peripheral blood mononuclear cells at gene expression level. The hypothesis tested in the present study was that long-term cryopreservation has an influence on the transcriptome profile of peripheral blood mononuclear cells. Results indicated remarkable changes in expression patterns upon cryopreservation of PBMCs, with decreasing signal intensities over time.
RNA-stabilized whole blood samples but not peripheral blood mononuclear cells can be stored for prolonged time periods prior to transcriptome analysis.
Sex, Age, Specimen part, Time
View SamplesAnalysis of cryopreservation effects on peripheral blood mononuclear cells at gene expression level. The hypothesis tested in the present study was that cryopreservation has an influence on the transcriptome profile of peripheral blood mononuclear cells. Results indicated remarkable changes in expression patterns upon cryopreservation of PBMCs, with a strong loss of signal intensities to background levels for several transcripts.
RNA-stabilized whole blood samples but not peripheral blood mononuclear cells can be stored for prolonged time periods prior to transcriptome analysis.
Age, Specimen part
View SamplesAnalysis of long-term freezing on the stability of transcriptome profiles in PAXgene stabilized whole blood samples. In the present study it was tested if long-term freezing of PAXgene RNA tubes (up to one year) has an influence on the transcriptome profile of peripheral whole blood samples. Results indicated that gene expression profiles of whole blood samples stabilized with PAXgene RNA tubes remain stable for at least 1 year.
RNA-stabilized whole blood samples but not peripheral blood mononuclear cells can be stored for prolonged time periods prior to transcriptome analysis.
Sex, Age, Specimen part, Time
View SamplesAlginate overproduction by P. aeruginosa, also known as mucoidy is associated with chronic endobronchial infections in cystic fibrosis (CF). Alginate biosynthesis in this bacterium is initiated by the extracytoplasmic function sigma factor (22, AlgU/T). In the wild type (wt) nonmucoid strains, such as PAO1, AlgU is sequestered by the anti-sigma factor MucA that inhibits alginate production. However, the degradation of MucA by activated intramembrane proteases AlgW and/or MucP can lead to the conversion from nonmucoid strains to mucoid. Previously we reported that the absence of the sensor kinase KinB in PAO1 causes the initiation of AlgW-dependent proteolysis of MucA resulting in alginate overproduction. In the kinB mutant this activation requires alternate sigma factor RpoN (54). To determine the RpoN-dependent KinB regulon, microarray and proteomic analyses were performed on a mucoid kinB mutant and an isogenic nonmucoid kinB rpoN double mutant. In the kinB mutant, RpoN controlled the expression of approximately 20% of the genome. Besides alginate biosynthesis and regulator genes such as AlgW, KinB, in concert with RpoN, also control a large number of genes including: those involved in carbohydrate metabolism, quorum sensing, iron regulation, rhamnolipid production, and motility. In an acute pneumonia murine infection model, mice exhibited better survival when challenged with the kinB mutant than wt PAO1. Together, these data strongly suggest that KinB controls virulence factors important for acute pneumonia and conversion to mucoidy.
Analysis of the Pseudomonas aeruginosa regulon controlled by the sensor kinase KinB and sigma factor RpoN.
Treatment
View SamplesCharacterization of bacterial behavior in the microgravity environment of spaceflight is of importance towards risk assessment and prevention of infectious disease during long-term missions. Further, this research field unveils new insights into connections between low fluid-shear regions encountered by pathogens during their natural infection process in vivo, and bacterial virulence. This study is the first to characterize the global transcriptomic and proteomic response of an opportunistic pathogen that is actually found in the space habitat, Pseudomonas aeruginosa. Overall, P. aeruginosa responded to spaceflight conditions through differential regulation of 167 genes and 28 proteins, with Hfq identified as a global transcriptional regulator in the response to this environment. Since Hfq was also induced in spaceflight-grown Salmonella typhimurium, Hfq represents the first spaceflight-induced regulator across the bacterial species border. The major P. aeruginosa virulence-related genes induced in spaceflight conditions were the lecA and lecB lectins and the rhamnosyltransferase (rhlA), involved in the production of rhamnolipids. The transcriptional response of spaceflight-grown P. aeruginosa was compared with our previous data of this organism grown in microgravity-analogue conditions using the rotating wall vessel (RWV) bioreactor technology. Interesting similarities were observed, among others with regard to Hfq regulation and oxygen utilization. While LSMMG-grown P. aeruginosa mainly induced genes involved in microaerophilic metabolism, P. aeruginosa cultured in spaceflight adopted an anaerobic mode of growth, in which denitrification was presumably most prominent. Differences in hardware between spaceflight and LSMMG experiments, in combination with more pronounced low fluid shear and mixing in spaceflight when compared to LSMMG conditions, were hypothesized to be at the origin of these observations. Collectively, our data suggest that spaceflight conditions could induce the transition of P. aeruginosa from an opportunistic organism to potential pathogen, results that are of importance for infectious disease risk assessment and prevention, both during spaceflight missions and in the clinic.
Transcriptional and proteomic responses of Pseudomonas aeruginosa PAO1 to spaceflight conditions involve Hfq regulation and reveal a role for oxygen.
No sample metadata fields
View SamplesThe Pseudomonas aeruginosa response regulator AlgR is critical for the organism's virulence and controls up to 155 different genes. In order to determine which genes are controlled by phosphorylated and unphosphorylated AlgR, phosphomimetic and phosphoablative alleles were recombined onto the chromosome of PAO1. The algR gene was mutated at aspartate 54 to asparagine (D54N) for the phosphoablative allele and mutated at aspartete 54 to glutamate (D54E) for the phosphomimetic allele. These alleles were recombined into the PAO1 chromosome.
<i>Pseudomonas aeruginosa</i> AlgR Phosphorylation Status Differentially Regulates Pyocyanin and Pyoverdine Production.
No sample metadata fields
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