Long term exposure to incretin hormones is known to have salutory effects on beta cell function and viability. While short-term cAMP induction is known to have a signature CREB-CRTC target gene response, the long-term effects of cAMP on beta cell gene expression are less well understood.
mTOR links incretin signaling to HIF induction in pancreatic beta cells.
Cell line, Time
View SamplesIn order to establish a list of candidate direct COUP-TFI gene targets in the inner ear, we analyzed the differential gene expression profiles of the wild-type and the COUP-TFI/ P0 inner ears.
Genome-wide analysis of binding sites and direct target genes of the orphan nuclear receptor NR2F1/COUP-TFI.
Specimen part
View SamplesAMPK (AAK-2) and calcineurin (TAX-6) mediate longevity exclusively through post-translational modification of CRTC-1, the sole C. elegans CRTC (CREB regulated transcriptional coactivator).
Lifespan extension induced by AMPK and calcineurin is mediated by CRTC-1 and CREB.
No sample metadata fields
View SamplesDuring 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 SamplesThe adipocyte-derived hormone leptin maintains energy balance by acting on hypothalamic leptin receptors (Leprs) that trigger the signal transducer and activator of transcription 3 (Stat3). Although disruption of Lepr-Stat3 signaling promotes obesity in mice, other features of Lepr function, such as fertility, seem normal, pointing to the involvement of additional regulators. Here we show that the cyclic AMP responsive elementbinding protein-1 (Creb1)-regulated transcription coactivator-1 (Crtc1) is required for energy balance and reproductionCrtc1-/- mice are hyperphagic, obese and infertile. Hypothalamic Crtc1 was phosphorylated and inactive in leptin-deficient ob/ob mice; leptin administration increased amounts of dephosphorylated nuclear Crtc1. Dephosphorylated Crtc1 stimulated expression of the Cartpt and Kiss1 genes, which encode hypothalamic neuropeptides that mediate leptins effects on satiety and fertility. Crtc1 overexpression in hypothalamic cells increased Cartpt and Kiss1 gene expression, whereas Crtc1 depletion decreased it. Indeed, leptin enhanced Crtc1 activity over the Cartpt and Kiss1 promoters in cells overexpressing Lepr and these effects were disrupted by expression of a dominant-negative Creb1 polypeptide. As leptin administration increased recruitment of hypothalamic Crtc1 to Cartpt and Kiss1 promoters, our results indicate that the Creb1-Crtc1 pathway mediates the central effects of hormones and nutrients on energy balance and fertility.
The Creb1 coactivator Crtc1 is required for energy balance and fertility.
No sample metadata fields
View SamplesIn fasted mammals, glucose homeostasis is maintained through activation of the cAMP responsive CREB coactivator TORC2, which stimulates the gluconeogenic program in concert with the forkhead transcription factor FOXO1. Here we show that starvation also triggers TORC activation in Drosophila, where it maintains energy balance by promoting the expression of CREB target genes in the brain. TORC mutant flies have reduced glycogen and lipid stores, and they are sensitive to starvation as well as oxidative stress. Neuronal TORC expression rescued starvation and oxidative stress sensitivity as well as CREB target gene expression in TORC mutants. During refeeding, increases in insulin signaling inhibited TORC activity in wild type flies by stimulating the Salt Inducible Kinase 2 (SIK2)-mediated phosphorylation and subsequent degradation of TORC. Depletion of neuronal SIK2 increased TORC activity and enhanced resistance to starvation and oxidative stress in adult flies. As disruption of insulin signaling, either by ablation of insulin-producing cells (IPCs) or by mutation of the insulin receptor adaptor gene chico, also increased TORC activity, our results illustrate the importance of an insulin-regulated pathway in brain that promotes energy balance in Drosophila.
The insulin-regulated CREB coactivator TORC promotes stress resistance in Drosophila.
No sample metadata fields
View SamplesWe studied the role of the cAMP responsive factor CREB in promoting insulin resistance following its activation in adipose under obese conditions
Adipocyte CREB promotes insulin resistance in obesity.
No sample metadata fields
View SamplesMale patients (n=6, mean age 62 years) with NYHA III-IV and an left ventricular ejection fraction of <35% despite pharmacological therapy received 35 hours of enhanced external counterpulsation (EECP) over a period of 7 weeks.
Effects of enhanced external counterpulsation on skeletal muscle gene expression in patients with severe heart failure.
Sex, Specimen part, Treatment, Subject
View SamplesThe CREB family of transcription factors stimulates cellular gene expression following phosphorylation at a conserved serine (Ser133 in CREB1) in response to cAMP and other extracellular signals. In order to characterize CREB target genes in various tissues, we give a cAMP agonist, forskolin (FSK), to cell lines or primary cultures and monitor the gene expression. To eliminate CREB-independent effects of FSK on cellular gene expression, we employed a dominant negative form of CREB called A-CREB, which dimerizes selectively with and blocks the DNA binding activity of CREB but not other bZIP family members. Therefore, genes that are induced by cAMP and the induction was blocked by A-CREB treatment likely represents CREB target genes.
Genome-wide analysis of cAMP-response element binding protein occupancy, phosphorylation, and target gene activation in human tissues.
No sample metadata fields
View SamplesOur findings demonstrate that CDCP1 is a novel modulator of HER2 signalling, and a biomarker for the stratification of breast cancer patients with poor prognosis
Interaction of CDCP1 with HER2 enhances HER2-driven tumorigenesis and promotes trastuzumab resistance in breast cancer.
Cell line
View Samples