Filters
Technology
Platform
GSE28953
Pseudomonas aeruginosa
6 Downloadable Samples
Affymetrix Pseudomonas aeruginosa Array (paeg1a)
Description
Biofilms 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.
Publication Title
The novel Pseudomonas aeruginosa two-component regulator BfmR controls bacteriophage-mediated lysis and DNA release during biofilm development through PhdA.
Sample Metadata Fields
No sample metadata fields
View Samples- Pseudomonas aeruginosa
- 6 Downloadable Samples
- Affymetrix Pseudomonas aeruginosa Array (paeg1a)
Description
A 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.
Publication Title
Microcolony formation by the opportunistic pathogen Pseudomonas aeruginosa requires pyruvate and pyruvate fermentation.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus, Homo sapiens
- 33 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Gene-chip studies of adipogenesis-regulated microRNAs in mouse primary adipocytes and human obesity.
Sample Metadata Fields
Age, Specimen part
View Samples- Homo sapiens
- 33 Downloadable Samples
Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Adipose tissue abundance relies partly on the factors that regulate adipogenesis, i.e. proliferation and differentiation of adipocytes. While the transcriptional program that initiates adipogenesis is well-known, the importance of microRNAs in adipogenesis is less well studied. We thus set out to investigate whether miRNAs would be actively modulated during adipogenesis and obesity. Several models exist to study adipogenesis in vitro, of which the cell line 3T3-L1 is probably the most well known, albeit not the most physiologically appropriate. We used a microarray strategy to provide a global profile of miRNAs in brown and white primary murine adipocytes (prior to and following differentiation) and evaluated the similarity of the responses to non-primary cell models, through literature data-mining. We found 65 miRNAs regulated during in vitro adipogenesis in primary adipocytes. When we compared our primary adipocyte profiles with those of cell lines reported in the literature, we found a high degree of difference in adipogenesis-regulated miRNAs. We evaluated the expression of 10 of our adipogenesis-regulated miRNAs using real-time qPCR and then selected 5 miRNAs that showed robust expression levels and profiled these by qPCR in subcutaneous adipose tissue of 20 humans with a range of body mass indices (BMI, range=21-48). Of the miRNAs tested, mir-21 was both highly expressed in human adipose tissue and positively correlated with BMI (R2=0.49, p<0.001). In conclusion, we provide the preliminary analysis of miRNAs important for primary cell in vitro adipogenesis and find that the inflammation-associated miRNA, mir-21, is up-regulated in subcutaneous adipose tissue in human obesity.
Publication Title
Gene-chip studies of adipogenesis-regulated microRNAs in mouse primary adipocytes and human obesity.
Sample Metadata Fields
Age
View Samples- Homo sapiens
- 4 Downloadable Samples
- Affymetrix Human Gene 2.0 ST Array (hugene20st)
Description
Proliferative cells isolated from the adult human peripheral retina only transiently upregulate key retinal markers upon induced differentiation.
Publication Title
Proliferative Cells Isolated from the Adult Human Peripheral Retina only Transiently Upregulate Key Retinal Markers upon Induced Differentiation.
Sample Metadata Fields
Specimen part, Time
View Samples- Homo sapiens
- 20 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patients protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments.
Publication Title
Dysregulation of mitochondrial dynamics and the muscle transcriptome in ICU patients suffering from sepsis induced multiple organ failure.
Sample Metadata Fields
Sex
View Samples- Homo sapiens
- 12 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
In this work, we isolated and characterized a novel cell population derived from human amniotic fluid cells (hAKPC-P), and we differentiated them into podocytes.
Publication Title
A novel source of cultured podocytes.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Homo sapiens
- 11 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
In this analysis we have compared the gene expression profiles of lymphatic endothelial cells (LECs) isolated from human intestine (iLECs) versus LECs from human skin (dLECs).
Publication Title
Liprin (beta)1 is highly expressed in lymphatic vasculature and is important for lymphatic vessel integrity.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 18 Downloadable Samples
Affymetrix Mouse Gene 2.0 ST Array (mogene20st), Illumina HiSeq 2000
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
N6-methyladenosine modification destabilizes developmental regulators in embryonic stem cells.
Sample Metadata Fields
Cell line, Treatment, Time
View Samples- Mus musculus
- 26 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Recent methylome studies have located N6-methyladenosine (m6A) RNA modification on thousands of mammalian transcripts. However, its functional mechanism remains unclear. In this study, we examined the role of m6A methylation in mouse embryonic stem cells.
Publication Title
N6-methyladenosine modification destabilizes developmental regulators in embryonic stem cells.
Sample Metadata Fields
Cell line, Treatment, Time
View Samples