Spatially resolved chimeric analysis reveals extracellular CKB-mediated ATP uptake at the glioma-astrocyte invasive front
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE283959 | GEO | 2025/06/30
REPOSITORIES: GEO
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Project description:The creatine-phosphocreatine cycle serves as a crucial temporary energy buffering system in the brain, regulated by brain creatine kinase (CKB). CKB, responsible for reversible phosphorylation of creatine, plays a pivotal role in maintaining ATP levels. Alzheimer's disease (AD) has been linked to increased CKB oxidation and loss of its functions, although specific pathological processes and affected cell types remain unclear.
In our study, cerebral cortex samples from AD, dementia with Lewy bodies (DLB), and age-matched controls were analyzed using antibody-based methods to quantify CKB levels and assess alterations associated with disease processes. Two independently validated antibodies exclusively labeled astrocytes in the human cerebral cortex. Immunofluorescence and Western blot analyses demonstrated a loss of CKB immunoreactivity correlated with increased plaque load, severity of tau pathology, and Lewy body pathology.
Combining antibody-based and mass spectrometry (MS) approaches, we explored CKB availability in AD and DLB. Transcriptomics and targeted MS revealed unaltered total CKB levels. Reduced antibody binding levels, confirmed by Western blot under denatured conditions, suggested post-translational modifications that affect antibody binding. This aligns with altered efficiency at proteolytic cleavage sites indicated in the targeted MS experiment.
These findings highlight that post-translational modifications extend to astrocytes, affecting their functions. CKB and the creatine-phosphocreatine cycle play crucial roles in energy buffering, securing constant ATP availability. Reduced ATP in astrocytes can disrupt ATP-dependent processes, such as the glutamate-glutamine cycle. Post-translational modifications in CKB and astrocyte dysfunction may disturb homeostasis, driving excitotoxicity in the AD brain. CKB and its activity emerge as potential biomarkers for monitoring early-stage energy deficits in AD.
2024-07-03 | PXD050060 | panorama
Project description:Creatine kinase (CK) is an essential metabolic enzyme mediating creatine/phosphocreatine interconversion and shuttle to replenish ATP for energy needs. Ablation of CK causes deficiency in energy supply that eventually results in reduced muscle burst activity and neurological disorders in mice. Besides the well-established role of CK in energy-buffering, the mechanism underlying non-metabolic function of CK is poorly understood. Here we demonstrate that creatine kinase brain-type (CKB) may function as a protein kinase to regulate BCAR1 Y327 phosphorylation that enhances the association between BCAR1 and RBBP4. Then the complex of BCAR1 and RPPB4 binds to the promoter region of DNA damage repair gene RAD51 and activates its transcription by modulating histone H4K16 acetylation to ultimately promote DNA damage repair. These findings reveal the possible role of CKB independently of its metabolic function and depict the potential pathway of CKB-BCAR1-RBBP4 operating in DNA damage repair.
2023-04-05 | PXD041365 |
Project description:Depletion of Nrf2 leads to an increase in cellular ROS, reduced glutathione and thiols, and profound reprogramming of metabolism. Unbiased transcriptome analyses show that key enzymes of glycolysis, pentose phosphate pathway, and glutathione cycle are significantly downregulated, while enzymes of arginine and medium-chain fatty acids metabolism are upregulated. Besides glutamine, pancreatic cancer cells deficient of Nrf2 axis become highly dependent on arginine, which is channelled into the synthesis of phosphocreatine and polyamines. Key enzymes of the creatine pathway, gatm and ckb, are more expressed and more active in Nrf2(-/-) than in WT cells. This metabolism shift creates an energy buffer that enables pancreatic cancer cells to handle increased energy demand. Metabolomic analysis showed that 12% of the creatine pool is phosphorylated in Nrf2(-/-) cells, while the level drops to < 0.1% in WT cells. The inhibition of the creatine pathway with cyclocreatine in Nrf2(-/-) cells, reduces by 43% the ATP level and by 70% invasion rate in matrigel. Furthermore, we found that combination therapies that can target simultaneously the creatine pathway and the KRAS G12D-Nrf2 axis produce a stronger anticancer effect than monotherapies. Taken together, our data provide the basis for the rationale design of new combination therapies against pancreatic cancer. The KRAS G12D-Nrf2 axis controls redox homeostasis and metabolism in PDAC cells. Suppression of KRAS G12D-Nrf2 decreases glycolysis, PPP and glutathione cycle and promotes a metabolic shift of arginine into the synthesis of phosphocreatine
2023-12-12 | GSE217965 | GEO
Project description:The mechanisms promoting disturbed white adipocyte function in obesity remain largely unclear. Herein, we integrate white adipose tissue (WAT) metabolomic and transcriptomic data from clinical cohorts and find that the WAT phosphocreatine/creatine ratio is increased and creatine kinase-B expression and activity is decreased in the obese state. . In human in vitro and murine in vivo models, we demonstrate that decreased phosphocreatine metabolism in white adipocytes alters AMPK activity via effects on ATP/ADP levels, independently of WAT beigeing. This disturbance promotes a pro-inflammatory profile characterized, in part, by increased CCL2 production. These data suggest that the phosphocreatine/creatine system links cellular energy shuttling with pro-inflammatory responses in human and murine white adipocytes. Our findings provide unexpected perspectives on the mechanisms driving WAT inflammation in obesity and may present avenues to target adipocyte dysfunction.
2022-01-27 | GSE192361 | GEO
Project description:Noradrenaline regulates cold-stimulated adipocyte thermogenesis. Aside from cAMP signaling downstream of β-adrenergic receptor (βAR) activation, how noradrenaline promotes thermogenic output is still not fully understood. Here, we show that coordinated α1-adrenergic receptor (α1AR) and β3AR signaling induces the expression of thermogenic genes of the futile creatine cycle, and that EBFs, ERRs, and PGC1α are required for this response in vivo. Noradrenaline triggers physical and functional coupling between the α1AR subtype (ADRA1A) to Gαq to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase b (CKB) and tissue-nonspecific alkaline phosphatase (TNAP). Combined Gαq and Gαs signaling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and CKB is required for this effect. Thus, the ADRA1A-Gαq-futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis.
2022-09-08 | GSE207341 | GEO
Project description:Noradrenaline regulates cold-stimulated adipocyte thermogenesis. Aside from cAMP signaling downstream of β-adrenergic receptor (βAR) activation, how noradrenaline promotes thermogenic output is still not fully understood. Here, we show that coordinated α1-adrenergic receptor (α1AR) and β3AR signaling induces the expression of thermogenic genes of the futile creatine cycle, and that EBFs, ERRs, and PGC1α are required for this response in vivo. Noradrenaline triggers physical and functional coupling between the α1AR subtype (ADRA1A) to Gαq to promote adipocyte thermogenesis in a manner that is dependent on the effector proteins of the futile creatine cycle, creatine kinase b (CKB) and tissue-nonspecific alkaline phosphatase (TNAP). Combined Gαq and Gαs signaling selectively in adipocytes promotes a continual rise in whole-body energy expenditure, and CKB is required for this effect. Thus, the ADRA1A-Gαq-futile creatine cycle axis is a key regulator of facultative and adaptive thermogenesis.
2022-09-08 | GSE207340 | GEO
Project description:Adaptive thermogenesis has attracted much attention because of its ability to raise systemic energy expenditure and counter obesity and diabetes. Recent data have indicated that thermogenic fat cells utilize creatine to stimulate futile substrate cycling, dissipating chemical energy as heat. This model was based on the super-stoichiometric relationship between creatine added to mitochondria and O2 consumed, and this project aims at providing direct evidence for the molecular basis of this futile creatine cycling activity. In this project, we found that thermogenic fat cells contain robust phosphocreatine hydrolase (PCr’ase) activity, attributable to tissue-nonspecific alkaline phosphatase (TNAP), which was identified by the quantitative mass spectrometric analysis of a purified mitochondrial protein fraction containing the PCr’ase activity. TNAP hydrolyzes phosphocreatine to initiate a futile cycle of creatine dephosphorylation and phosphorylation; it is localized to mitochondria of thermogenic fat cells, where the futile creatine cycling occurs. Furthermore, we demonstrated in this project the essential role of TNAP in activating the futile creatine cycling and increasing whole body energy expenditure using genetic and pharmacological approaches. We also found that the genetic depletion of TNAP in murine adipose tissue causes rapid-onset obesity, with no change in movement or feeding behavior of the animals. Using quantitative mass spectrometry, we showed that genetic depletion of TNAP causes an upregulation of UCP1, as well as other proteins involved in oxidative metabolism, to compensate for a dampened thermogenesis. In summary, the data we acquired in this project illustrate the critical role of TNAP as a phosphocreatine phosphatase in the futile creatine cycling and adipose thermogenesis.
2022-02-17 | PXD025032 | Pride
Project description:Placental insufficiency is often associated with fetal growth restriction (FGR), a condition associated with both short- and long-term complications for the newborn. In this study, we performed comprehensive transcriptomic and metabolomic analyses to delineate the metabolic profiles that distinguish newborns with FGR from those born with appropriate-for-gestational- age (AGA) status. By comparing our RNA-seq data with placental transcriptome data from the POP dataset, we identified common enrichment categories, notably hypoxia, as well as alterations in creatine and arginine metabolism. In infants with FGR, placental insufficiency tends to promote anaerobic metabolism, resulting in limited ATP production. To counteract this deficiency, arginine is used to synthesise phosphocreatine, an energy-rich compound that is crucial for ATP production. Increased biosynthesis of polyamines addition, our observations show an upregulation of SAT1 acetyltransferase that contributes to decreased concentrations of spermidine and N1-acetylspermidine as well as increased N1,N8-diacetylspermidine concentrations in the placenta of FGR infants. Increased .In summary, our study improves the understanding of metabolic adaptations associated with placental dysfunction in FGR and provides valuable insights for future therapeutic interventions.
2024-12-06 | GSE262116 | GEO
Project description:This model is from the article:
Analyzing the functional properties of the creatine kinase system with multiscale 'sloppy' modeling.
Hettling H, van Beek JH
PLoS Comput Biol.2011 Aug;7(8):e1002130.
PMEDID,
Abstract:
In this study the function of the two isoforms of creatine kinase (CK; EC 2.7.3.2) in myocardium is investigated. The 'phosphocreatine shuttle' hypothesis states that mitochondrial and cytosolic CK plays a pivotal role in the transport of high-energy phosphate (HEP) groups from mitochondria to myofibrils in contracting muscle. Temporal buffering of changes in ATP and ADP is another potential role of CK. With a mathematical model, we analyzed energy transport and damping of high peaks of ATP hydrolysis during the cardiac cycle. The analysis was based on multiscale data measured at the level of isolated enzymes, isolated mitochondria and on dynamic response times of oxidative phosphorylation measured at the whole heart level. Using 'sloppy modeling' ensemble simulations, we derived confidence intervals for predictions of the contributions by phosphocreatine (PCr) and ATP to the transfer of HEP from mitochondria to sites of ATP hydrolysis. Our calculations indicate that only 15±8% (mean±SD) of transcytosolic energy transport is carried by PCr, contradicting the PCr shuttle hypothesis. We also predicted temporal buffering capabilities of the CK isoforms protecting against high peaks of ATP hydrolysis (3750 µM*s(-1)) in myofibrils. CK inhibition by 98% in silico leads to an increase in amplitude of mitochondrial ATP synthesis pulsation from 215±23 to 566±31 µM*s(-1), while amplitudes of oscillations in cytosolic ADP concentration double from 77±11 to 146±1 µM. Our findings indicate that CK acts as a large bandwidth high-capacity temporal energy buffer maintaining cellular ATP homeostasis and reducing oscillations in mitochondrial metabolism. However, the contribution of CK to the transport of high-energy phosphate groups appears limited. Mitochondrial CK activity lowers cytosolic inorganic phosphate levels while cytosolic CK has the opposite effect.
This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2012 The BioModels.net Team.
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To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.
2024-09-02 | BIOMD0000000408 | BioModels
Project description:Glioblastoma ( GBM) is an astrocytic brain tumor with median survival times of < 15 months, primarily as a result of high infiltrative potential and development of resistance to therapy (i.e., surgical resection, chemoradiotherapy). A prominent feature of the GBM microenvironment is compressive solid stress (CSS) caused by uninhibited tumor growth within the confined skull. We used microarrays to explore the gene expression of LN229 cells treated with 23 Pa CSS as compared to no CSS. The purpose is to detect the up-regulated genes induced by CSS.
2019-12-31 | GSE137210 | GEO