Ampk activation by glycogen expenditure primes the exit of naïve pluripotency
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ABSTRACT:
PROVIDER: PRJNA1137399 | ENA |
REPOSITORIES: ENA
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Project description:Embryonic and epiblast stem cells in pre-and post-implantation embryos are characterized by their naïve and primed states, respectively, which represent distinct phases of pluripotency. Thus, the cellular transition from naïve to primed pluripotency recapitulates a drastic metabolic and cellular remodeling after implantation to adapt to changes in extracellular conditions. Here, we found that inhibition of Ampk occurred during naïve transition with two conventional inhibitors (2i) of the Mek1 and Gsk3 pathways. The accumulation of glycogen due to the inhibition of Gsk3 was responsible for Ampk inhibition, which accounted for high de novo fatty acid synthesis in naïve embryonic stem cells (ESCs). The knockout of glycogen synthase 1 (Gys1) in naïve ESCs (GKO), resulting in a drastic glycogen loss, led to a robust Ampk activation and lowered the level of fatty acids. GKO lost the cellular characteristics of naïve ESCs and rapidly transitioned to a primed state. The characteristics of GKO were restored by the simultaneous knockout of Ampk. These findings suggest that glycogen in naïve ESCs within the blastocyst may act as a signaling molecule for the timely activation of Ampk, thus ultimately contributing to the transition to the epiblast stage.
2024-10-15 | GSE272593 | GEO
Project description:Physical activity promotes metabolic and cardiovascular health benefits that derive in part from the transcriptional responses to exercise that occur within skeletal muscle and other organs. There is interest in discovering a pharmacologic exercise mimetic that could imbue wellness and alleviate disease burden. However, the molecular physiology by which exercise signals the transcriptional response is highly complex, making it challenging to identify a single target for pharmacological mimicry. The current studies evaluated the transcriptome responses in skeletal muscle, heart, liver, and white and brown adipose to novel small molecule activators of AMPK (pan-activators for all AMPK isoforms) compared to that of exercise. A striking level of congruence between exercise and pharmacological AMPK activation was observed across the induced transcriptome of these five tissues. However, differences in acute metabolic response between exercise and pharmacologic AMPK activation were observed, notably for acute glycogen balances and related to the energy expenditure induced by exercise but not pharmacologic AMPK activation. Nevertheless, intervention with repeated daily administration of short-acting activation of AMPK was found to mitigate hyperglycemia and hyperinsulinemia in four rodent models of metabolic disease and without the cardiac glycogen accretion noted with sustained pharmacologic AMPK activation. These findings affirm that activation of AMPK is a key node governing exercise mediated transcription and is an attractive target as an exercise mimetic.
2019-02-27 | GSE92719 | GEO
Project description:Loss of PRC2 subunits primes lineage choice during exit of pluripotency
| PRJNA646712 | ENA
Project description:A single bout of exercise followed by intake of carbohydrates leads to glycogen supercompensation in the prior exercised muscle. The molecular mechanisms underlying this well-known phenomenon remain elusive. Here we report that a single bout of exercise induces marked activation of glycogen synthase (GS) and AMP-activated protein kinase (AMPK) for several days beyond normalized muscle glycogen content in man. Acute muscle specific deletion of AMPK activity in mouse muscle abrogated the ability for glycogen supercompensation, providing genetic evidence that AMPK serves as essential driver for glycogen supercompensation. Muscle proteomic analyses revealed elevated glucose uptake capacity in the prior exercised muscle while key proteins in fat oxidation and glycolysis largely remained unchanged. The temporal order of these sustained cellular alterations induced by a single bout of exercise provide a mechanism to offset the otherwise tight feedback inhibition of glycogen synthesis and glucose uptake by glycogen, ultimately leading to muscle glycogen supercompensation.
2018-08-30 | PXD009196 | Pride
Project description:Glycogenin is considered essential for glycogen synthesis as it acts as a primer for the initiation of the polysaccharide. In this study, we challenge this notion and demonstrate that glycogen can be synthesized in vivo in the absence of glycogenin. Glycogenin-deficient mice (Gyg KO) accumulate high amounts of the polysaccharide in skeletal and cardiac striated muscles. This glycogen shows no covalently bound protein, thereby indicating that no protein primer is essential for glycogen synthesis. Gyg KO mice show lower resting energy expenditure and lesser resistance when subjected to endurance exercise than control animals, which can be attributed to a switch of oxidative myofibers toward glycolytic metabolism. This switch is caused by the over-accumulation of glycogen, since mice overexpressing glycogen synthase specifically in skeletal muscle show a similar metabolic alteration. These results may explain the muscular defects of GSD XV patients, who show high glycogen accumulation in striated muscles.
2017-07-06 | PXD006377 | Pride
Project description:Non-alcoholic fatty liver disease (NAFLD) is a chronic disease caused by hepatic steatosis. Adenosine deaminases acting on RNA (ADARs) catalyze adenosine to inosine RNA editing. However, the functional role of ADAR2 in NAFLD is unclear. ADAR2+/+/GluR-BR/R mice (wild type, WT) and ADAR2−/−/GluR-BR/R mice (ADAR2 KO) mice were fed with standard chow or high-fat diet (HFD) for 12 weeks. ADAR2 KO mice exhibited protection against HFD–induced glucose intolerance, insulin resistance, and dyslipidemia. Moreover, ADAR2 KO mice displayed reduced liver lipid droplets in concert with decreased hepatic TG content, improved hepatic insulin signaling, better pyruvate tolerance, and increased glycogen synthesis. Mechanistically, ADAR2 KO effectively mitigated excessive lipid production via AMPK/Sirt1 pathway. ADAR2 KO inhibited hepatic gluconeogenesis via the AMPK/CREB pathway and promoted glycogen synthesis by activating the AMPK/GSK3β pathway. These results provided novel evidence that ADAR2 KO protected against NAFLD progression through activation of AMPK signaling pathways.
2024-03-14 | GSE261185 | 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:Mitotic exit requires extensive dephosphorylation of Ser/Thr residues by the PP1 and PP2A-B55 protein phosphatases in human cells. Several aspects of this are poorly understood including specific substrates and determinants of phosphatase specificity. Here we develop a novel in vitro assay, MRBLE-dephos, that allows multiplexing of dephosphorylation reactions to determine phosphatase specificity. Using MRBLE-dephos, we establish amino acid preferences of the residues surrounding the phosphorylation site for PP1 and PP2A-B55, which reveals common and unique preferences for the two phosphatases. We use specific inhibition of PP1 and PP2A-B55 in mitotic exit lysates coupled with quantitative phosphoproteomics to identify more than 2000 regulated phosphorylation sites and integrate this with mitotic interactomes to obtain a comprehensive map of mitotic dephosphorylation events. Importantly, the sites dephosphorylated during mitotic exit reveal key signatures that are consistent with the MRBLE-dephos results. We use these insights to specifically alter INCENP dephosphorylation kinetics at mitotic exit resulting in defective cytokinesis underscoring the biological relevance of our determined specificity principles. Finally, we provide a comprehensive characterization of PP1 binding motifs and show how these can shape dephosphorylation and how PP1 primes its own association with these motifs at mitotic exit. Collectively we provide a framework for understanding mitotic exit regulation by dephosphorylation and novel approaches to dissect protein phosphatase specificity.
2023-05-12 | MSV000091928 | MassIVE