During fasting, increases in circulating pancreatic glucagon maintain glucose balance by up-regulating hepatic gluconeogenesis. Triggering of the cAMP pathway stimulates the gluconeogenic program through the phosphorylation of CREB and via the de-phosphorylation of the CREB coactivator CRTC2. Hormonal and nutrient signals are also thought to modulate gluconeogenic genes by promoting epigenetic changes that facilitate assembly of the transcriptional machinery, although the nature of these modifications is unclear. Here we show that histone H3 acetylation at Lys 9 (H3K9Ac) is elevated over gluconeogenic genes during fasting and in diabetes, where it contributes to increases in hepatic glucose production. Following its dephosphorylation, CRTC2 promoted increases in H3K9Ac by mediating the recruitment of the lysine acetyltransferase 2B (KAT2B) and WD repeat-containing protein 5 (WDR5), a core subunit of histone methyltransferase (HMT) complexes. In turn, KAT2B and WDR5 stimulated the gluconeogenic program through a self-reinforcing cycle whereby increases in H3K9Ac further potentiated CRTC2 occupancy at CREB binding sites. Breaking this cycle, by depletion of KAT2B or WDR5, decreased gluconeogenic gene expression. As administration of a small molecule KAT2B antagonist lowered circulating blood glucose concentrations in insulin resistance, our results demonstrate how this enzyme may be a useful target for diabetes treatment.
Glucagon regulates gluconeogenesis through KAT2B- and WDR5-mediated epigenetic effects.
Sex, Age, Specimen part
View SamplesStaphylococcus aureus is a highly adaptable human pathogen; therefore a constant search for new effective antibiotic compounds is being preformed. Gene expression profiling can be used to determine potential targets and mechanisms of action (MOA) of known or potential drugs. The goal of our study was a development of a focused transcriptome platform to be used for confirming the MOA of new chemical entities which are designed as inhibitors of Mur ligases. A model transcriptional profile was set up for well described inhibitor of MurA ligase, fosfomycin. Moreover, we wanted to identify the pathways and processes primarily affected by this compound. S. aureus ATCC 29213 cells were treated with low concentrations of fosfomycin (1 and 4 g/ml, respectively) and harvested at 10, 20 and 40 minutes after treatment, respectively. RNA was isolated, transcribed, labeled and hybridized to S. aureus GeneChips, representing approximately 3000 S. aureus genes.
Revealing fosfomycin primary effect on Staphylococcus aureus transcriptome: modulation of cell envelope biosynthesis and phosphoenolpyruvate induced starvation.
No sample metadata fields
View SamplesThe goal was to screen for the expressed genes in Semi-Circular Canal Duct (SCCD) that are related to ion transport and its regulation. The objectives was to discover which genes changed expression levels in response to glucocorticoids.
Ion transport regulation by P2Y receptors, protein kinase C and phosphatidylinositol 3-kinase within the semicircular canal duct epithelium.
Specimen part
View SamplesFollowing infection with LCMV, CD4+ SMARTA TCR transgenic cells (specific for the gp61-80 epitope of the LCMV glycoprotein) rapidly expand, become effector cells, and go on to form a long-lived memory population. Following infection with a recombinant Listeria monocytogenes expressing the LCMV epitope gp61-80, SMARTA cells also expand but display defective effector differentiation and fail to form memory. In an attempt to understand the signals required for CD4 T cell memory differentiation, we compared gene expression by SMARTA cells at the peak of the primary response following either Lm-gp61 or LCMV infection.
Rapid culling of the CD4+ T cell repertoire in the transition from effector to memory.
No sample metadata fields
View SamplesIn prior work we developed an optogenetic system for delivering highly precise, time-varying inputs to Ras, termed OptoSOS (Toettcher et al., 2013). This system relies on a membrane-targeted photoswitchable protein (Phy-CAAX) and a cytoplasmic Ras activator (PIF-SOScat) whose localization to the membrane can be controlled with light. In this system, Phy/PIF heterodimerization can be triggered on and off by exposure to 650 and 750 nm light, respectively. We found that this system could be used to deliver highly precise levels and dynamics of Ras/Erk signaling both in vitro and in vivo. Here, we aimed to globally assess the transcriptional response to light-activated Ras and compare it to that induced by growth factor stimulation. We stimulated NIH3T3 OptoSOS cells with either constant activating red light or PDGF and measured transcriptional responses by RNAseq. Total mRNA was collected after 0, 30, 60 and 120 minutes and used to track the dynamics of transcript abundance in both conditions. Genes were defined as upregulated if they satisfied two criteria: (i) induced at least three-fold over unstimulated cells, and (ii) induced at least two consecutive timepoints. By these criteria we detected 118 genes that were upregulated within 2 h by either PDGF or light stimulation, a comparable number of Ras-responsive genes to that found in previous studies. We found that both PDGF and light induced nearly identical profiles of gene expression, with 100/118 genes induced by PDGF and 110/118 induced by light. At each time point we found excellent agreement between the levels of gene induction in response to both stimuli. This agreement also extended to response dynamics. where hierarchical clustering revealed three classes of dynamic response: an early response peaking within 30 min, an intermediate response peaking at ~1 h, and a late response where gene expression gradually increased over the full 2 h timecourse. In all three classes, we found that light and PDGF led to highly similar expression changes over time. We thus concluded that sole stimulation of the Ras/Erk pathway by light was sufficient to recapitulate at least the first two hours of the PDGF-induced transcriptional response. Overall design: RNA-seq to measure global transcript abundance at various timepoints after PDGF stimulation or direct optogenetic activation of Ras using the OptoSOS system in NIH3T3 cells (Toettcher et al, Cell 2013). 9 samples were collected using the TruSeq library preparation kit (Illumina), multiplexed, pooled and measured in 3 lanes of an Illumina Hi-Seq 2000. Library quality was assessed by Agilent Bioanalyzer. Roughly 30-50 million reads were measured per sample across all 3 lanes. Baseline transcript abundance was measured in triplicate (0 min controls) and each successive timepoint was measured in a single collection. Genes were considered upregulated if they were induced at least 5-fold in at least two consecutive timepoints relative to their baseline abundance.
Tracing Information Flow from Erk to Target Gene Induction Reveals Mechanisms of Dynamic and Combinatorial Control.
Specimen part, Subject
View SamplesThe goal was to screen for the expressed genes in Reissner's membrane (RM) that are related to ion transport and its regulation. The objectives were 1) to determine whether short-term incubation altered the transcriptome and 2 ) to discover which genes changed expression levels in response to glucocorticoids.
Regulation of ENaC-mediated sodium transport by glucocorticoids in Reissner's membrane epithelium.
Specimen part
View SamplesFusarium head blight (FHB) is a major disease of cereal crops caused by the fungus Fusarium graminearum (Fg). FHB affects the flowering heads (or spikes) and developing seeds. This study compare the gene expression profile in wheat spikelets (spk 2) inoculated with either water (mock treatment) or a pathogenic strain of Fusarium graminearum (WT); spikelets 2 were inoculated 24 hrs after a neighbour spikelet (spk 0) was treated with either water or F. graminerum mutant strain Tri6 or NoxAB. Spikelets 2 were sampled 8 and 24 hrs after the second treatment.
Components of priming-induced resistance to Fusarium head blight in wheat revealed by two distinct mutants of Fusarium graminearum.
Specimen part
View SamplesThe innate immune system is vital to rapidly responding to pathogens and Toll-like receptors (TLRs) are a critical component of this response. Nanovesicular exosomes play a role in immunity, but to date their exact contribution to the dissemination of the TLR response is unknown. To understand the effect of exosomal cargo released from locally stimulated cells on distal cell expression, we collected exosomes from local ovarian adenocarcinoma (HEY) cells that were either unstimulated (control-exosomes), stimulated with pIC (pIC-exosomes), or lipopolysaccharide (LPS-exosomes) for 48 hours. The three groups of exosomes were added to nave (distal) cells and the gene expression profiles were compared between local TLR stimulation (for 6 hours) and distal stimulation mediated by exosomes at the 48-hour time point
TLR-exosomes exhibit distinct kinetics and effector function.
Specimen part, Cell line, Treatment
View SamplesThe histone acetyltransferase (HAT) Mof is essential for mouse embryonic stem cells (mESC) pluripotency and early development. Mof is the enzymatic subunit of two different HAT complexes, MSL (Male-Specific Lethal) and NSL (Non-specific lethal). The individual contribution of MSL and NSL complexes to transcription regulation in mESCs is not well understood. Our genome-wide analysis of MSL and NSL localization show that i) MSL and NSL bind to specific and common sets of expressed genes, ii) NSL binds at promoters, iii) while MSL binds in gene bodies. Knockdown of Msl1 leads to a global loss of histone H4K16ac indicating that MSL is the main HAT acetylating H4K16 in mESCs. MSL was enriched at many mESC-specific genes, but also at bivalent domains. Thus, NSL and MSL HAT complexes differentially regulate specific sets of expressed genes in mESCs. Furthermore, MSL is essential for the regulation of key mESC-specific and bivalent developmental genes.
Mof-associated complexes have overlapping and unique roles in regulating pluripotency in embryonic stem cells and during differentiation.
No sample metadata fields
View SamplesIn this experiment, we sought to analyze how the transcriptome of WT, ?5|6, and ?5|6:7|9 cells vary during differentiation of ESCs into cervical motor neurons Overall design: 3 lines (WT, ?5|6, ?5|6:7|9)
CTCF establishes discrete functional chromatin domains at the Hox clusters during differentiation.
No sample metadata fields
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