The Mediator complex kinase module is necessary for fructose regulation of liver glycogen levels through induction of glucose-6-phosphatase catalytic subunit (G6pc)
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA693002 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR13477744_1.fastq.gz | Fastqsanger.gz | |||
| SRR13477744_2.fastq.gz | Fastqsanger.gz | |||
| SRR13477746_1.fastq.gz | Fastqsanger.gz | |||
| SRR13477746_2.fastq.gz | Fastqsanger.gz | |||
| SRR13477747_1.fastq.gz | Fastqsanger.gz |
Items per page: 5 1 - 5 of 24 |
Similar Datasets
Project description:Liver glycogen levels are dynamic and highly regulated by nutrient availability as the levels decrease during fasting and are restored during the feeding cycle. However, feeding in the presence of fructose in water suppressed glycogen accumulation in the liver by up-regulating the expression of glucose-6-phosphatase catalytic subunit (G6pc) gene although the exact mechanism is unknown. We generated liver specific knockout of MED13 mice that lack the transcriptional Mediator complex kinase module to examine its effect on transcriptional activation of inducible target gene expression, such as the ChREBP- and FOXO1-dependent control of the G6pc gene promoter.
2021-04-04 | GSE165033 | GEO
Project description:ObjectiveLiver glycogen levels are dynamic and highly regulated by nutrient availability as the levels decrease during fasting and are restored during the feeding cycle. However, feeding in the presence of fructose in water suppresses glycogen accumulation in the liver by upregulating the expression of the glucose-6-phosphatase catalytic subunit (G6pc) gene, although the exact mechanism is unknown. We generated liver-specific knockout MED13 mice that lacked the transcriptional Mediator complex kinase module to examine its effect on the transcriptional activation of inducible target gene expression, such as the ChREBP- and FOXO1-dependent control of the G6pc gene promoter.MethodsThe relative changes in liver expression of lipogenic and gluconeogenic genes as well as glycogen levels were examined in response to feeding standard low-fat laboratory chow supplemented with water or water containing sucrose or fructose in control (Med13fl/fl) and liver-specific MED13 knockout (MED13-LKO) mice.ResultsAlthough MED13 deficiency had no significant effect on constitutive gene expression, all the dietary inducible gene transcripts were significantly reduced despite the unchanged insulin sensitivity in the MED13-LKO mice compared to that in the control mice. G6pc gene transcription displayed the most significant difference between the Med13 fl/fl and MED13-LKO mice, particularly when fed fructose. Following fasting that depleted liver glycogen, feeding induced the restoration of glycogen levels except in the presence of fructose. MED13 deficiency rescued the glycogen accumulation defect in the presence of fructose. This resulted from the suppression of G6pc expression and thus G6PC enzymatic activity. Among two transcriptional factors that regulate G6pc gene expression, FOXO1 binding to the G6pc promoter was not affected, whereas ChREBP binding was dramatically reduced in MED13-LKO hepatocytes. In addition, there was a marked suppression of FOXO1 and ChREBP-β transcriptional activities in MED13-LKO hepatocytes.ConclusionsTaken together, our data suggest that the kinase module of the Mediator complex is necessary for the transcriptional activation of metabolic genes such as G6pc and has an important role in regulating glycogen levels in the liver through altering transcription factor binding and activity at the G6pc promoter.
| S-EPMC8099662 | biostudies-literature
Project description:Excessive fructose intake is a risk factor for the development of obesity and its complications. Targeting ketohexokinase (KHK), the first enzyme of fructose metabolism, has been investigated for the management of MASLD. We compared the effects of systemic, small molecule inhibitor of KHK enzymatic activity to hepatocyte-specific, GalNAc-siRNA mediated knockdown of KHK in mice on a HFD. We measured KHK enzymatic activity, extensively quantified glycogen accumulation, performed RNAseq analysis, and enumerated hepatic metabolites using mass spectrometry. Both KHK siRNA and KHK inhibitor led to an improvement in liver steatosis, however, via substantially different mechanisms. KHK knockdown decreased the de novo lipogenesis pathway, whereas the inhibitor increased the fatty acid oxidation pathway. Moreover, KHK knockdown completely prevented hepatic fructolysis and improved glucose tolerance. Conversely, the KHK inhibitor only partially reduced fructolysis, but it also targeted triokinase, mediating the third step of fructolysis. This leads to the accumulation of fructose-1 phosphate, resulting in glycogen accumulation, hepatomegaly, and impaired glucose tolerance. Overexpression of wild-type, but not kinase-dead KHK in cultured hepatocytes increased hepatocyte injury and glycogen accumulation when treated with fructose. The differences between KHK inhibition and knockdown are, in part, explained by the kinase-dependent and independent effects of KHK on hepatic metabolism.
2024-11-14 | GSE278322 | GEO
Project description:Glycogen storage, conversion and utilization in astrocytes play important roles in brain energy metabolism. The conversion of glycogen to lactate through glycolysis occurs through the coordinated activities of various enzymes, and inhibition of this process can impair different brain processes including formation of long-lasting memories. To replenish depleted glycogen stores, astrocytes undergo glycogen synthesis, a cellular process that has been shown to require transcription and translation during specific stimulation paradigms. However, the detailed nuclear signaling mechanisms and transcriptional regulation during glycogen synthesis in astrocytes remain to be explored. In this report, we study the molecular details of vasoactive intestinal peptide (VIP)-induced glycogen synthesis in astrocytes. VIP is a potent neuropeptide that triggers glycogenolysis followed by glycogen synthesis in astrocytes. We show evidence that VIP-induced glycogen synthesis requires CREB-mediated transcription that is Protein Kinase C and calcium-dependent but is independent of Protein Kinase A. In parallel to CREB activation, we demonstrate that VIP also triggers nuclear accumulation of the CREB coactivator CRTC2 only in astrocytic nuclei that also requires Protein Kinase C activity. Transcriptome profiles of VIP-induced astrocytes identified robust CREB-dependent transcription of glycogenic genes including the upregulation of Ppp1r3c along with robust repression of Phkg1, the catalytic subunit of phosphorylase kinase. Overall, our data demonstrates the importance of CREB-mediated transcription in astrocytes during stimulus-driven glycogenesis.
2024-04-30 | GSE243500 | GEO
Project description:Glycogen and lipid are major storage forms of energy that are tightly regulated by hormones and metabolic signals. Here, we evaluate the role of the glycogenic scaffolding protein PTG/R5 in energy homeostasis. We demonstrate that feeding mice a high-fat diet (HFD) increases hepatic glycogen, corresponding to increased PTG levels, increased activity of the mechanistic target of rapamycin complex 1 (mTORC1) and induced expression of sterol regulatory element binding protein 1c (SREBP1c). PTG promoter activity was increased by activation of mTORC1 and SREBP1, and PTG and glycogen levels were augmented in mice and cells in which mTORC1 is constitutively active. HFD-dependent increases in hepatic glycogen were prevented by deletion of the PTG gene in mice. Interestingly, PTG knockout mice fed HFD exhibited improved liver steatosis and decreased lipid levels in muscle, in coordination with decreased glycogen, suggesting possible crosstalk between glycogen and lipid stores in the overall control of energy metabolism. Together, these data suggest that transcriptional regulation of PTG by dietary and nutritional cues has profound effects on energy storage and metabolism.fi RNA-Seq analysis was used to characterize hepatic diet-associated gene expression changes between wild-type and PTG KO mice. Mice were maintained on a normal chow diet or a high-fat diet as indicated. 2-3 biological replicates per genotype/diet.
2014-06-13 | E-GEOD-45319 | biostudies-arrayexpress
Project description:Glycogen and lipid are major storage forms of energy that are tightly regulated by hormones and metabolic signals. Here, we evaluate the role of the glycogenic scaffolding protein PTG/R5 in energy homeostasis. We demonstrate that feeding mice a high-fat diet (HFD) increases hepatic glycogen, corresponding to increased PTG levels, increased activity of the mechanistic target of rapamycin complex 1 (mTORC1) and induced expression of sterol regulatory element binding protein 1c (SREBP1c). PTG promoter activity was increased by activation of mTORC1 and SREBP1, and PTG and glycogen levels were augmented in mice and cells in which mTORC1 is constitutively active. HFD-dependent increases in hepatic glycogen were prevented by deletion of the PTG gene in mice. Interestingly, PTG knockout mice fed HFD exhibited improved liver steatosis and decreased lipid levels in muscle, in coordination with decreased glycogen, suggesting possible crosstalk between glycogen and lipid stores in the overall control of energy metabolism. Together, these data suggest that transcriptional regulation of PTG by dietary and nutritional cues has profound effects on energy storage and metabolism.fi
2014-06-13 | GSE45319 | GEO
Project description:To decipher the beneficial effects of Polyphenols on health, healthy volunteers were randomized into two groups and were submitted to either a red grape polyphenol rich extract supplemented diet (PP) or a placebo diet (PCB) during 8 weeks. Then they were submitted to a fructose load (3g/kg Fat Free Mass/day) during 7 days. Muscle biopsies were taken before the protocol, 8 weeks after PP or PCB diet and after the 7 days fructose load. We have employed whole genome microarray expression profiling as a discovery platform to identify genes regulated by fructose and to identify the mechanism of action of Polyphenols. Healthy volunteers were randomized into two groups and were submitted to either a red grape polyphenol rich extract supplemented diet (PP) or a placebo diet (PCB) during 8 weeks. Then they were submitted to a fructose load (3g/kg Fat Free Mass/day) during 7 days. Muscle biopsies were taken before the protocol, 8 weeks after PP or PCB diet and after the 7 days fructose load. We have employed whole genome microarray expression profiling as a discovery platform to identify genes regulated by fructose and to identify the mechanism of action of Polyphenols. Ten biological replicates were processed for PP diet, nine for PCB diet.
2013-02-04 | E-GEOD-35764 | biostudies-arrayexpress
Project description:Glycogen is the largest soluble cytosolic macromolecule and considered as the principal storage form of glucose. Cancer cells generally increase their glucose consumption and rewire their metabolism towards aerobic glycolysis to promote growth. Here we report that glycogen accumulation is a key initiating oncogenic event and essential for malignant transformation. RNA-sequencing analysis reveals that G6PC, an enzyme catalyzing the last step of glycogenolysis, is frequently downregulated to augment glucose storage in pro-tumor cells. Accumulated glycogen undergoes liquid-liquid phase separation undergoes liquid-liquid phase separation, which results in the assembly of the laforin-Mst1/2 complex and consequently traps Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme PYGL deficiency in both human and mice result in glycogen storage disease with enlarged liver size and cancer development, phenocopying Hippo deficiency. Consistently, elimination of glycogen accumulation abrogates liver enlargement and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that glycogen not only provides nutrition and energy to the cells but also functions as a key initiating oncogenic metabolite, which physically blocks Hippo signaling through glycogen phase separation to augment pro-tumor cell initiation and progression.
2021-10-06 | GSE148933 | GEO
Project description:Mll3/Mll4 catalytic activity is necessary for de novo enhancer-promoter contacts during embryonic stem cell differentiation
| PRJNA674785 | ENA
Project description:This proposed study is designed to investigate the specific uptake of fructose by human colorectal tumors. In this study, subjects with colorectal cancer undergoing surgery will receive an oral sugar solution containing fructose or xylose prior to surgery. The tumor will then be resected, and a portion of the tissue will be used to measure the abundance of fructose and xylose. The study hypothesis is that the tumors will take up fructose sugar but not xylose sugar. A comparison of the sugar uptake between the tumor and normal tissues from the adjacent intestinal epithelium and smooth muscle and the liver will be conducted. This proposal will confirm that human colorectal cancer tumors can directly absorb dietary sugars, which has never been demonstrated.
| 2396702 | ecrin-mdr-crc