Study of the role of AMP-activated protein kinase (AMPK) in heart
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE18843 | GEO | 2015/02/24
SECONDARY ACCESSION(S): PRJNA121181
REPOSITORIES: GEO
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Project description:AMP-activated protein 1 kinase (AMPK), a phylogenetically conserved serine/threonine kinase regarded as a key cellular energy sensor, exists in eukaryotes as a heterotrimer comprising a catalytic α and regulatory β and γ subunits. In humans, activating mutations in the gene encoding the γ2 subunit of AMPK (PRKAG2) display a cardiac phenotype of left ventricular hypertrophy (LVH), conduction system disease, ventricular pre-excitation and increased cardiomyocyte glycogen accumulation. While existing transgenic models have elucidated the pathogenesis of several aspects of the disease5-7, the slow heart rate (sinus bradycardia) – a prominent feature of the disease – remains poorly understood. Here, using gene-targeting to generate mice which recapitulate this bradycardia, we demonstrate that γ2 AMPK activation perturbs fundamental mechanisms that determine sinoatrial pacemaker cell function. Reduction in the sarcolemmal hyperpolarization activated (“funny”) current (If) and damping of ryanodine receptor-derived diastolic local subsarcolemmal Ca2+ releases (LCRs)12,13 contribute to reduced sinoatrial cell spontaneous activity and, ultimately, to a lower heart rate. Pharmacological activation of AMPK reversibly reduces the beating rate of murine pluripotent stem cell-derived induced sinoatrial bodies. In contrast, using a mouse knock-out of γ2 AMPK, which exhibits an increased heart rate, we demonstrate a role for γ2 AMPK in physiological heart rate regulation, including an indispensable role in the bradycardic adaptation to endurance exercise. Through regulating the cardiac pacemaker and thereby heart rate, γ2 AMPK by virtue of its energy-sensing role, is a key physiological determinant of overall cardiac energy homeostasis.
2017-09-30 | GSE73047 | GEO
Project description:Analysis of AMPK gamma3-dependent transcriptional responses by analyzing global gene expression in the white portion of the gastrocnemius muscle in AMPK gamma3 knock-out mice and corresponding wild type littermates.
2007-12-14 | E-GEOD-4063 | biostudies-arrayexpress
Project description:Metabolic dysfunction of skeletal muscle is often prevalent at an early stage in the development of several non-communicable diseases. Here, we investigated the effect of a myokine, secreted protein acidic and rich in cysteine (SPARC), on glucose tolerance in human and mouse skeletal muscles. SPARC knockout mice showed marked decreases in parameters for whole-body glucose metabolism, along with reduced phosphorylation of AMPK and Akt in skeletal muscle tissues compared with wild-type mice. Furthermore, mice injected with SPARC showed improved glucose tolerance concomitant with AMPK activation. Exogenous SPARC treatment accelerated glucose uptake in muscle tissues isolated from wild-type mice but not from AMPKγ3 knockout mice. In muscle cells, SPARC increased glucose uptake concomitant with AMPK activation, mediated by a calcium-dependent signal. Chronic treatment of SPARC restored metabolic functions in diet-induced obese mice. These findings suggest that SPARC improves glucose metabolism via AMPK activation in skeletal muscle, providing mechanistic insights on exercise-induced metabolic benefits and physical inactivity-induced glucose intolerance.
2019-06-03 | GSE93546 | GEO
Project description:Renal cyst development and expansion in autosomal dominant polycystic kidney disease (ADPKD) involves both fluid secretion and abnormal proliferation of cyst-lining epithelial cells. The chloride channel of the cystic fibrosis transmembrane conductance regulator (CFTR) participates in secretion of cyst fluid, and the mammalian target of rapamycin (mTOR) pathway may drive proliferation of cyst epithelial cells. CFTR and mTOR are both negatively regulated by AMP-activated protein kinase (AMPK). Metformin, a drug in wide clinical use, is a pharmacological activator of AMPK. We find that metformin stimulates AMPK, resulting in inhibition of both CFTR and the mTOR pathways. Metformin induces significant arrest of cystic growth in both in vitro and ex vivo models of renal cystogenesis. In addition, metformin administration produces a significant decrease in the cystic index in two mouse models of ADPKD. Our results suggest a possible role for AMPK activation in slowing renal cystogenesis as well as the potential for therapeutic application of metformin in the context of ADPKD.
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Project description:Transcriptional profiling to assess atrial gene expression in atrial LKB1 KO vs. AMPK KO vs. WT mice.
2022-04-05 | GSE200144 | GEO
Project description:Mitochondrial reactive oxygen species (ROS) production is a tightly regulated redox signal that transmits information from the organelle to the cell. Other mitochondrial signals, such as ATP, are sensed by enzymes, including the key metabolic sensor and regulator, AMP-activated protein kinase (AMPK). AMPK responds to the cellular ATP/AMP and ATP/ADP ratios by matching mitochondrial ATP production to demand. Previous reports proposed that AMPK activity also responds to ROS, by ROS acting on redox-sensitive cysteine residues (Cys-299/Cys-304) on the AMPK ? subunit. This suggests an appealing model in which mitochondria fine-tune AMPK activity by both adenine nucleotide-dependent mechanisms and by redox signals. Here we assessed whether physiological levels of ROS directly alter AMPK activity. To this end we added exogenous hydrogen peroxide (H2O2) to cells and utilized the mitochondria-targeted redox cycler MitoParaquat to generate ROS within mitochondria without disrupting oxidative phosphorylation. Mitochondrial and cytosolic thiol oxidation was assessed by measuring peroxiredoxin dimerization and by redox-sensitive fluorescent proteins. Replacing the putative redox-active cysteine residues on AMPK ?1 with alanines did not alter the response of AMPK to H2O2 In parallel with measurements of AMPK activity, we measured the cell ATP/ADP ratio. This allowed us to separate the effects on AMPK activity due to ROS production from those caused by changes in this ratio. We conclude that AMPK activity in response to redox changes is not due to direct action on AMPK itself, but is a secondary consequence of redox effects on other processes, such as mitochondrial ATP production.
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Project description:AMP-activated-protein-kinase (AMPK) is a key sensor and regulator of cellular and whole-body energy metabolism and plays a key role in regulation of lipid metabolism. Since lipid metabolism has been implicated in neuronal amyloid-beta (Abeta) homeostasis and onset of Alzheimer's disease, we investigated the involvement of AMPK in neuronal lipid metabolism and Abeta production. We observed in cultured rat cortical neurons that Abeta production was significantly reduced when the neurons were stimulated with AMPK activator, 5-aminoimidazole-4-carboxamide-1-d-ribofuranoside (AICAR), but increased when AMPKalpha2 was knocked out, thus indicating the role of AMPK in amyloidogenesis. Although the detailed mechanisms by which AMPK regulates Abeta generation is not well understood, AMPK-mediated alterations in cholesterol and sphingomyelin homeostasis and in turn the altered distribution of Abeta precursor-protein (APP) in cholesterol and sphingomyelin rich membrane lipid rafts participate in Abeta generation. Taken together, this is the first report on the role of AMPK in regulation of neuronal amyloidogenesis.
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Project description:Long non-coding RNAs (lncRNA) and circular RNAs (circRNA) that sponge miRNAs could indirectly regulate gene expression, contributing to certain biological processes. This study aimed to investigate the role of non-coding RNAs in the pathogenesis of myocardial ischemia reperfusion-injury (MIRI). MIRI in male C57B/6J mice was induced by left anterior descending coronary artery ligation occlusion for 30 min, and 4 h of reperfusion. RNA sequencing was performed to obtain the mRNA and non-coding RNA expression profiles of the MIRI and sham groups. Bioinformatic methods were used to analyze the co-expression RNAs, miRNA binding sites and competitive endogenous RNA (ceRNA) pairs. Differentially expressed RNAs were identified with a cutoff fold change > 2 and p < 0.05. A total of 64 mRNAs were upregulated and 98 mRNAs were downregulated, and 10 lncRNAs were upregulated and 10 lncRNAs were downregulated. All altered (p < 0.05) mRNAs were selected for gene ontology and pathway analysis. The AMP-activated protein kinase (AMPK) signaling pathway was enriched in the downregulated genes, and the activation of AMPK was confirmed by Western blotting. The lncRNA co-expression network and ceRNA network base on genes in AMPK signaling pathway were then constructed, revealing that ENSMUST00000147762.7 and TUCP_000184 might be key regulators in MIRI induced AMPK activation. The expression levels of AMPK signaling-related RNAs and those involved in the ceRNA network were validated using qRT-PCR. Overall, this study identified potential new targets on AMPK signaling in MIRI.
2024-04-01 | GSE240842 | GEO
Project description:AMP-activated protein kinase (AMPK) is a central cellular energy sensor that adapts metabolism and growth to the energy state of the cell. AMPK senses the ratio of adenine nucleotides (adenylate energy charge) by competitive binding of AMP, ADP, and ATP to three sites (CBS1, CBS3, and CBS4) in its ?-subunit. Because these three binding sites are functionally interconnected, it remains unclear how nucleotides bind to individual sites, which nucleotides occupy each site under physiological conditions, and how binding to one site affects binding to the other sites. Here, we comprehensively analyze nucleotide binding to wild-type and mutant AMPK protein complexes by quantitative competition assays and by hydrogen-deuterium exchange MS. We also demonstrate that NADPH, in addition to the known AMPK ligand NADH, directly and competitively binds AMPK at the AMP-sensing CBS3 site. Our findings reveal how AMP binding to one site affects the conformation and adenine nucleotide binding at the other two sites and establish CBS3, and not CBS1, as the high affinity exchangeable AMP/ADP/ATP-binding site. We further show that AMP binding at CBS4 increases AMP binding at CBS3 by 2 orders of magnitude and reverses the AMP/ATP preference of CBS3. Together, these results illustrate how the three CBS sites collaborate to enable highly sensitive detection of cellular energy states to maintain the tight ATP homeostastis required for cellular metabolism.
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Project description:AMP-activated protein kinase (AMPK) is a central metabolic regulator that promotes cancer growth and survival under hypoxia and plays a role in the maintenance of cancer stem cells. A major challenge to interrogating the potential of targeting AMPK in cancer is the lack of potent and selective small molecule inhibitors. Compound C has been widely used as an AMPK inhibitor, but it lacks potency and has a poor selectivity profile. The multi-kinase inhibitor, sunitinib, has demonstrated potent nanomolar inhibition of AMPK activity and has scope for modification. Here, we have designed and synthesized several series of oxindoles to determine the structural requirements for AMPK inhibition and to improve selectivity. We identified two potent, novel oxindole-based AMPK inhibitors that were designed to interact with the DFG motif in the ATP-binding site of AMPK, this key feature evades interaction with the common recptor tyrosine kinase targets of sunitinib. Cellular engagement of AMPK by these oxindoles was confirmed by the inhibition of phosphorylation of acetyl-CoA carboxylase (ACC), a known substrate of AMPK, in myeloid leukemia cells. Interestingly, although AMPK is highly expressed and activated in K562 cells these oxindole-based AMPK inhibitors did not impact cell viability or result in significant cytotoxicity. Our studies serve as a platform for the further development of oxindole-based AMPK inhibitors with therapeutic potential.
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