Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are often caused by strains encoding Panton-Valentine leukocidin (PVL). PVL can cause lysis of polymorphonuclear leukocytes (PMNs) and other myeloid cells in vitro, a function considered widely as the primary means by which PVL might contribute to disease. However, at sublytic concentrations PVL can function as a PMN agonist. To better understand this phenomenon, we investigated the ability of PVL to alter human PMN function. PMNs exposed to PVL had enhanced capacity to produce superoxide in response to N-formyl-methionyl-leucyl-phenylalanine (fMLF), but unlike priming by lipopolysaccharide, this response did not require Toll-like receptor signal transduction. On the other hand, there was subcellular redistribution of NADPH oxidase components in PMNs following exposure of these cells to PVL - a finding consistent with priming. Priming of PMNs with other agonists such as IL-8 or GM-CSF altered the ability PVL to cause formation of pores in the plasma membranes of these cells. Microarray analysis revealed significant changes in the human PMN transcriptome following exposure to PVL, including up-regulation of molecules that regulate the inflammatory response. Consistent with the microarray data, mediators of the inflammatory response were released from PMNs after stimulation with PVL. We conclude that exposure of human PMNs to sublytic concentrations of PVL elicits a proinflammatory response that is regulated in part at the level of gene expression. We propose that PVL-mediated priming of PMNs enhances the host innate immune response.
Sublytic concentrations of Staphylococcus aureus Panton-Valentine leukocidin alter human PMN gene expression and enhance bactericidal capacity.
Specimen part
View SamplesNeutrophil lysis after phagocytosis is a process potentially important in the pathogenesis of community-associated methicillin-resistant S. aureus (CA-MRSA) infection. The mechanism for this process is not currently known. Therefore, to better understand CA-MRSA virulence we used human oligonucleotide microarrays to investigate the mechanism underlying enhanced PMN lysis that occurs after phagocytosis of CA-MRSA.
Rapid neutrophil destruction following phagocytosis of Staphylococcus aureus.
Specimen part, Treatment
View SamplesWe investigated the nutritional effects on gene expression in sperm cells of F0 boars from a three generation Large White pig feeding experiment. A group of experimental (E) F0 boars were fed a standard diet supplemented with high amounts of methylating micronutrients whereas a control (C) group of F0 boars received a standard diet. These differentially fed F0 boars sired F1 boars which then sired 60 F2 pigs which were investigated in a previous study. The aim of this study was to investigate if the nutrition affects gene expression in sperm cells of differentially fed boars and thus carry information in the form of RNA molecules to the next generation. Four RNA samples from sperm cells of these differentially fed boars were analyzed by RNA-Seq methodology. We found no differential RNA expression in sperm cells of the two groups based on the adjusted P-value > 0.05. Nevertheless, we performed a pathway analysis with 105 genes that differed in gene expression on the level of nominal P-value < 0.05 between the two diet groups. We found a significant number of these differentially expressed genes were enriched for the pathway maps of bacterial infections in cystic fibrosis (CF) airways, glycolysis and gluconeogenesis p.3 and cell cycle_Initiation of mitosis. The GO processes including a significant portion of differentially expressed genes were viral transcription and viral genome expression, viral infectious cycle, cellular protein localization, cellular macromolecule localization, nuclear-transcribed mRNA catabolic process and nonsense-mediated decay. In summary, the results of the pathway analysis are also inconclusive and it is concluded that RNA expression in sperm cells is not significantly affected by extensive supplementation of methylating micronutrients. Consequently, RNA molecules could not be established as epigenetic marks in this feeding experiment. Overall design: Gene expression in sperm cells from differentially fed F0 boars was measured. F0 boars received either a standard diet or a standard diet supplemented with methylating micronutrients. These boars were used to study transgenerational epigenetic inheritance in a three generation pig pedigree. Therefore it was of interest if the diet affects gene expression in sperm cells which could then be transmitted to next generations.
In search of epigenetic marks in testes and sperm cells of differentially fed boars.
Sex, Specimen part, Subject
View SamplesThe cellular response to DNA damage is mediated through multiple pathways that regulate and coordinate DNA repair, cell cycle arrest and cell death. We show that the DNA damage response (DDR) induced by ionizing radiation (IR) is coordinated in breast cancer cells by selective mRNA translation mediated by high levels of translation initiation factor eIF4G1. Increased expression of eIF4G1, common in breast cancers, was found to selectively increase translation of mRNAs involved in cell survival and the DDR, preventing autophagy and apoptosis (Survivin, HIF1, XIAP), promoting cell cycle arrest (GADD45a, p53, ATRIP, Chk1) and DNA repair (53BP1, BRCA1/2, PARP, Rfc2-5, ATM, MRE-11, others). Reduced expression of eIF4G1, but not its homolog eIF4G2, greatly sensitizes cells to DNA damage by IR, induces cell death by both apoptosis and autophagy, and significantly delays resolution of DNA damage foci with little reduction of overall protein synthesis. While some mRNAs selectively translated by higher levels of eIF4G1 were found to use internal ribosome entry site (IRES)-mediated alternate translation, most do not. The latter group shows significantly reduced dependence on eIF4E for translation, facilitated by an enhanced requirement for eIF4G1. Increased expression of eIF4G1 therefore promotes specialized translation of survival, growth arrest and DDR mRNAs that are important in cell survival and DNA repair following genotoxic DNA damage.
DNA damage and eIF4G1 in breast cancer cells reprogram translation for survival and DNA repair mRNAs.
Cell line
View SamplesPrevious results suggest that Bmh might inhibit the activity of the transcription factor Adr1 after binding to Adr1-dependent promoters. In a strain lacking the two major histone deacetylases, Hda1 and Rpd3 (hdac), Adr1 is bound to its target promoters recruiting what appears to be an inactive RNA ploymerase II preinitiation complex (PIC). To determine whether Bmh activity inhibits this inactive PIC and the generality of this effect on glucose-repressed gene expression, the mRNA profiles of wild type, bmh mutant, hdac mutant, and bmh hdac mutant cells grown in high glucose medium were compared.
14-3-3 (Bmh) proteins regulate combinatorial transcription following RNA polymerase II recruitment by binding at Adr1-dependent promoters in Saccharomyces cerevisiae.
No sample metadata fields
View SamplesTranslation initiation factors have complex functions in cells which are not yet understood. We show that depletion of initiation factor eIF4GI only modestly reduces overall protein synthesis in cells, but phenocopies nutrient-starvation or inhibition of protein kinase mTOR, a key nutrient sensor. eIF4GI depletion impairs cell proliferation, bioenergetics and mitochondrial activity, thereby promoting autophagy. Translation of mRNAs involved in cell growth, proliferation and bioenergetics were selectively inhibited by reduction of eIF4GI, whereas mRNAs encoding proliferation inhibitors and catabolic pathway factors were increased. Depletion or over-expression of other eIF4G family members did not recapitulate these results. The majority of mRNAs that were translationally impaired with eIF4GI depletion were excluded from polyribosomes due to the presence of multiple upstream open reading frames and low mRNA abundance. These results suggest that the high levels of eIF4GI observed in many breast cancers might act to specifically increase proliferation, prevent autophagy and release tumor cells from control by nutrient sensing.
eIF4GI links nutrient sensing by mTOR to cell proliferation and inhibition of autophagy.
No sample metadata fields
View SamplesAnalysis of the regulation of gene expression profiles by retinoblastoma-1 in Sertoli cells. Conditional knockout of Rb1 in Sertoli cells led to progressive infertiliy in male mice that occured between 10 and 14 weeks of age. Results of gene expression studies performed on 6 week-old purified Sertoli cells helped elucidate the key role of RB1 in mature, differentiated Sertoli cells.
Retinoblastoma protein plays multiple essential roles in the terminal differentiation of Sertoli cells.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Characterisation of cisplatin-induced transcriptomics responses in primary mouse hepatocytes, HepG2 cells and mouse embryonic stem cells shows conservation of regulating transcription factor networks.
Cell line, Treatment, Time
View SamplesThe transcriptomic changes induced in the human liver cell line HepG2 by 7M of cisplatin after treatment for 12, 24 and 48h
Characterisation of cisplatin-induced transcriptomics responses in primary mouse hepatocytes, HepG2 cells and mouse embryonic stem cells shows conservation of regulating transcription factor networks.
Cell line, Treatment, Time
View SamplesThe transcriptomic changes induced in primary mouse hepatocytes (C57BL/6 ) by 7M of cisplatin after treatment for 24 and 48h
Characterisation of cisplatin-induced transcriptomics responses in primary mouse hepatocytes, HepG2 cells and mouse embryonic stem cells shows conservation of regulating transcription factor networks.
Cell line, Treatment, Time
View Samples