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Park SS, Yang G, Kim E. Lactobacillus acidophilus NS1 Reduces Phosphoenolpyruvate Carboxylase Expression by Regulating HNF4α Transcriptional Activity. Korean J Food Sci Anim Resour 2017; 37:529-534. [PMID: 28943765 PMCID: PMC5599573 DOI: 10.5851/kosfa.2017.37.4.529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 12/19/2022] Open
Abstract
Probiotics have been known to reduce high-fat diet (HFD)-induced metabolic diseases, such as obesity, insulin resistance, and type 2 diabetes. We recently observed that Lactobacillus acidophilus NS1 (LNS1), distinctly suppresses increase of blood glucose levels and insulin resistance in HFD-fed mice. In the present study, we demonstrated that oral administration of LNS1 with HFD feeding to mice significantly reduces hepatic expression of phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme in gluconeogenesis which is highly increased by HFD feeding. This suppressive effect of LNS1 on hepatic expression of PEPCK was further confirmed in HepG2 cells by treatment of LNS1 conditioned media (LNS1-CM). LNS1-CM strongly and specifically inhibited HNF4α-induced PEPCK promoter activity in HepG2 cells without change of HNF4α mRNA levels. Together, these data demonstrate that LNS1 suppresses PEPCK expression in the liver by regulating HNF4α transcriptional activity, implicating its role as a preventive or therapeutic approach for metabolic diseases.
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Affiliation(s)
- Sung-Soo Park
- Department of Biological Sciences, College of Science, Chonnam National University, Gwangju 61186, Korea
| | - Garam Yang
- Department of Biological Sciences, College of Science, Chonnam National University, Gwangju 61186, Korea
| | - Eungseok Kim
- Department of Biological Sciences, College of Science, Chonnam National University, Gwangju 61186, Korea
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52
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Triphenyltin recognition by primary structures of effector proteins and the protein network of Bacillus thuringiensis during the triphenyltin degradation process. Sci Rep 2017. [PMID: 28646170 PMCID: PMC5482883 DOI: 10.1038/s41598-017-04014-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Herein, triphenyltin (TPT) biodegradation efficiency and its transformation pathway have been elucidated. To better understand the molecular mechanism of TPT degradation, the interactions between amino acids, primary structures, and quaternary conformations of effector proteins and TPT were studied. The results verified that TPT recognition and binding depended on amino acid sequences but not on secondary, tertiary or quaternary protein structure. During this process, TPT could change the molecular weight and isoelectric point of effector proteins, induce their methylation or demethylation, and alter their conformation. The effector proteins, alkyl hydroperoxide reductase and acetyl-CoA acetyltransferase, recognizing TPT were crucial to TPT degradation. Electron transfer flavoprotein subunit alpha, phosphoenolpyruvate carboxykinase, aconitate hydratase, branched-chain alpha-keto acid dehydrogenase E1 component, biotin carboxylase and superoxide dismutase were related to energy and carbon metabolism, which was consistent with the results in vivo. The current findings develop a new approach for investigating the interactions between proteins and target compounds.
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53
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Weber C, Schäff C, Kautzsch U, Börner S, Erdmann S, Bruckmaier R, Röntgen M, Kuhla B, Hammon H. Variable liver fat concentration as a proxy for body fat mobilization postpartum has minor effects on insulin-induced changes in hepatic gene expression related to energy metabolism in dairy cows. J Dairy Sci 2017; 100:1507-1520. [DOI: 10.3168/jds.2016-11808] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/07/2016] [Indexed: 12/11/2022]
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54
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Wesolowski SR, Hay WW. Role of placental insufficiency and intrauterine growth restriction on the activation of fetal hepatic glucose production. Mol Cell Endocrinol 2016; 435:61-68. [PMID: 26723529 PMCID: PMC4921201 DOI: 10.1016/j.mce.2015.12.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023]
Abstract
Glucose is the major fuel for fetal oxidative metabolism. A positive maternal-fetal glucose gradient drives glucose across the placenta and is sufficient to meet the demands of the fetus, eliminating the need for endogenous hepatic glucose production (HGP). However, fetuses with intrauterine growth restriction (IUGR) from pregnancies complicated by placental insufficiency have an early activation of HGP. Furthermore, this activated HGP is resistant to suppression by insulin. Here, we present the data demonstrating the activation of HGP in animal models, mostly fetal sheep, and human pregnancies with IUGR. We also discuss potential mechanisms and pathways that may produce and support HGP and hepatic insulin resistance in IUGR fetuses.
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Affiliation(s)
- Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, University of Colorado School of Medicine, Colorado Anschutz Medical Campus, Aurora, CO, USA
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55
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Chen WW, Freinkman E, Wang T, Birsoy K, Sabatini DM. Absolute Quantification of Matrix Metabolites Reveals the Dynamics of Mitochondrial Metabolism. Cell 2016; 166:1324-1337.e11. [PMID: 27565352 PMCID: PMC5030821 DOI: 10.1016/j.cell.2016.07.040] [Citation(s) in RCA: 303] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/08/2016] [Accepted: 07/25/2016] [Indexed: 01/08/2023]
Abstract
Mitochondria house metabolic pathways that impact most aspects of cellular physiology. While metabolite profiling by mass spectrometry is widely applied at the whole-cell level, it is not routinely possible to measure the concentrations of small molecules in mammalian organelles. We describe a method for the rapid and specific isolation of mitochondria and use it in tandem with a database of predicted mitochondrial metabolites ("MITObolome") to measure the matrix concentrations of more than 100 metabolites across various states of respiratory chain (RC) function. Disruption of the RC reveals extensive compartmentalization of mitochondrial metabolism and signatures unique to the inhibition of each RC complex. Pyruvate enables the proliferation of RC-deficient cells but has surprisingly limited effects on matrix contents. Interestingly, despite failing to restore matrix NADH/NAD balance, pyruvate does increase aspartate, likely through the exchange of matrix glutamate for cytosolic aspartate. We demonstrate the value of mitochondrial metabolite profiling and describe a strategy applicable to other organelles.
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Affiliation(s)
- Walter W Chen
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Elizaveta Freinkman
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Tim Wang
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Kıvanç Birsoy
- Laboratory of Metabolic Regulation and Genetics, The Rockefeller University, New York City, NY 10065, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Broad Institute of Harvard and Massachusetts Institute of Technology, 7 Cambridge Center, Cambridge, MA 02142, USA.
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56
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Escós M, Latorre P, Hidalgo J, Hurtado-Guerrero R, Carrodeguas JA, López-Buesa P. Kinetic and functional properties of human mitochondrial phosphoenolpyruvate carboxykinase. Biochem Biophys Rep 2016; 7:124-129. [PMID: 28955899 PMCID: PMC5613351 DOI: 10.1016/j.bbrep.2016.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 11/28/2022] Open
Abstract
The cytosolic form of phosphoenolpyruvate carboxykinase (PCK1) plays a regulatory role in gluconeogenesis and glyceroneogenesis. The role of the mitochondrial isoform (PCK2) remains unclear. We report the partial purification and kinetic and functional characterization of human PCK2. Kinetic properties of the enzyme are very similar to those of the cytosolic enzyme. PCK2 has an absolute requirement for Mn2+ ions for activity; Mg2+ ions reduce the Km for Mn2+ by about 60 fold. Its specificity constant is 100 fold larger for oxaloacetate than for phosphoenolpyruvate suggesting that oxaloacetate phosphorylation is the favored reaction in vivo. The enzyme possesses weak pyruvate kinase-like activity (kcat=2.7 s−1). When overexpressed in HEK293T cells it enhances strongly glucose and lipid production showing that it can play, as the cytosolic isoenzyme, an active role in glyceroneogenesis and gluconeogenesis. Purification of recombinant human PCK2 has been performed. Its kinetic behavior is very similar to that of human PCK1. PCK2 overexpression increases gluconeogenesis and glyceroneogenesis in cell cultures.
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Affiliation(s)
- Miriam Escós
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain
| | - Pedro Latorre
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, 50013 Zaragoza, Spain.,Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain
| | - Jorge Hidalgo
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, 50013 Zaragoza, Spain.,Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain
| | - Ramón Hurtado-Guerrero
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain.,Fundación ARAID, Gobierno de Aragón, Zaragoza, Spain
| | - José Alberto Carrodeguas
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain.,Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, Spain.,IIS Aragón, 50009 Zaragoza, Spain
| | - Pascual López-Buesa
- Departamento de Producción Animal y Ciencia de los Alimentos, Facultad de Veterinaria, Universidad de Zaragoza, 50013 Zaragoza, Spain.,Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), BIFI-IQFR (CSIC) Joint Unit, Universidad de Zaragoza, 50009 Zaragoza, Aragón, Spain
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57
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Argininosuccinate synthetase regulates hepatic AMPK linking protein catabolism and ureagenesis to hepatic lipid metabolism. Proc Natl Acad Sci U S A 2016; 113:E3423-30. [PMID: 27247419 DOI: 10.1073/pnas.1606022113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A key sensor of cellular energy status, AMP-activated protein kinase (AMPK), interacts allosterically with AMP to maintain an active state. When active, AMPK triggers a metabolic switch, decreasing the activity of anabolic pathways and enhancing catabolic processes such as lipid oxidation to restore the energy balance. Unlike oxidative tissues, in which AMP is generated from adenylate kinase during states of high energy demand, the ornithine cycle enzyme argininosuccinate synthetase (ASS) is a principle site of AMP generation in the liver. Here we show that ASS regulates hepatic AMPK, revealing a central role for ureagenesis flux in the regulation of metabolism via AMPK. Treatment of primary rat hepatocytes with amino acids increased gluconeogenesis and ureagenesis and, despite nutrient excess, induced both AMPK and acetyl-CoA carboxylase (ACC) phosphorylation. Antisense oligonucleotide knockdown of hepatic ASS1 expression in vivo decreased liver AMPK activation, phosphorylation of ACC, and plasma β-hydroxybutyrate concentrations. Taken together these studies demonstrate that increased amino acid flux can activate AMPK through increased AMP generated by ASS, thus providing a novel link between protein catabolism, ureagenesis, and hepatic lipid metabolism.
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58
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Zhang Q, Koser SL, Donkin SS. Propionate induces mRNA expression of gluconeogenic genes in bovine calf hepatocytes. J Dairy Sci 2016; 99:3908-3915. [DOI: 10.3168/jds.2015-10312] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/04/2015] [Indexed: 11/19/2022]
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59
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Seenappa V, Das B, Joshi MB, Satyamoorthy K. Context Dependent Regulation of Human Phosphoenolpyruvate Carboxykinase Isoforms by DNA Promoter Methylation and RNA Stability. J Cell Biochem 2016; 117:2506-20. [DOI: 10.1002/jcb.25543] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 03/15/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Venu Seenappa
- Department of Biotechnology; School of Life Sciences; Manipal University; Manipal India
| | - Bidyadhar Das
- Department of Zoology; Northeast Hill University; Shillong India
| | - Manjunath B. Joshi
- Department of Biotechnology; School of Life Sciences; Manipal University; Manipal India
| | - Kapaettu Satyamoorthy
- Department of Biotechnology; School of Life Sciences; Manipal University; Manipal India
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60
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Shum M, Bellmann K, St-Pierre P, Marette A. Pharmacological inhibition of S6K1 increases glucose metabolism and Akt signalling in vitro and in diet-induced obese mice. Diabetologia 2016; 59:592-603. [PMID: 26733005 DOI: 10.1007/s00125-015-3839-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/13/2015] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS The mammalian target of rapamycin complex 1 (mTORC1)/p70 ribosomal S6 kinase (S6K)1 pathway is overactivated in obesity, leading to inhibition of phosphoinositide 3-kinase (PI3K)/Akt signalling and insulin resistance. However, chronic mTORC1 inhibition by rapamycin impairs glucose homeostasis because of robust induction of liver gluconeogenesis. Here, we compared the effect of rapamycin with that of the selective S6K1 inhibitor, PF-4708671, on glucose metabolism in vitro and in vivo. METHODS We used L6 myocytes and FAO hepatocytes to explore the effect of PF-4708671 on the regulation of glucose uptake, glucose production and insulin signalling. We also treated high-fat (HF)-fed obese mice for 7 days with PF-4708671 in comparison with rapamycin to assess glucose tolerance, insulin resistance and insulin signalling in vivo. RESULTS Chronic rapamycin treatment induced insulin resistance and impaired glucose metabolism in hepatic and muscle cells. Conversely, chronic S6K1 inhibition with PF-4708671 reduced glucose production in hepatocytes and enhanced glucose uptake in myocytes. Whereas rapamycin treatment inhibited Akt phosphorylation, PF-4708671 increased Akt phosphorylation in both cell lines. These opposite effects of the mTORC1 and S6K1 inhibitors were also observed in vivo. Indeed, while rapamycin treatment induced glucose intolerance and failed to improve Akt phosphorylation in liver and muscle of HF-fed mice, PF-4708671 treatment improved glucose tolerance and increased Akt phosphorylation in metabolic tissues of these obese mice. CONCLUSIONS/INTERPRETATION Chronic S6K1 inhibition by PF-4708671 improves glucose homeostasis in obese mice through enhanced Akt activation in liver and muscle. Our results suggest that specific S6K1 blockade is a valid pharmacological approach to improve glucose disposal in obese diabetic individuals.
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Affiliation(s)
- Michael Shum
- Department of Medicine, Quebec Heart and Lung Institute, Hôpital Laval, Pavillon Marguerite d'Youville, Room Y4308, 2705 Chemin Ste-Foy, Québec, Canada, G1V 4G5
| | - Kerstin Bellmann
- Department of Medicine, Quebec Heart and Lung Institute, Hôpital Laval, Pavillon Marguerite d'Youville, Room Y4308, 2705 Chemin Ste-Foy, Québec, Canada, G1V 4G5
| | - Philippe St-Pierre
- Department of Medicine, Quebec Heart and Lung Institute, Hôpital Laval, Pavillon Marguerite d'Youville, Room Y4308, 2705 Chemin Ste-Foy, Québec, Canada, G1V 4G5
| | - André Marette
- Department of Medicine, Quebec Heart and Lung Institute, Hôpital Laval, Pavillon Marguerite d'Youville, Room Y4308, 2705 Chemin Ste-Foy, Québec, Canada, G1V 4G5.
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61
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Leptin signaling regulates glucose homeostasis, but not adipostasis, in the zebrafish. Proc Natl Acad Sci U S A 2016; 113:3084-9. [PMID: 26903647 DOI: 10.1073/pnas.1513212113] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leptin is the primary adipostatic factor in mammals. Produced largely by adipocytes in proportion to total adipose mass, the hormone informs the brain regarding total energy stored as triglycerides in fat cells. The hormone acts on multiple circuits in the brain to regulate food intake, autonomic outflow, and endocrine function to maintain energy balance. In addition to regulating adipose mass, mammalian leptin also plays a role in the regulation of glucose homeostasis and as a gating factor in reproductive competence. Leptin-deficient mice and people exhibit early onset profound hyperphagia and obesity, diabetes, and infertility. Although leptin and the leptin receptor are found in fish, the hormone is not expressed in adipose tissue, but is found in liver and other tissues. Here, we show that adult zebrafish lacking a functional leptin receptor do not exhibit hyperphagia or increased adiposity, and exhibit normal fertility. However, leptin receptor-deficient larvae have increased numbers of β-cells and increased levels of insulin mRNA. Furthermore, larval zebrafish have been shown to exhibit β-cell hyperplasia in response to high fat feeding or peripheral insulin resistance, and we show here that leptin receptor is required for this response. Adult zebrafish also have increased levels of insulin mRNA and other alterations in glucose homeostasis. Thus, a role for leptin in the regulation of β-cell mass and glucose homeostasis appears to be conserved across vertebrates, whereas its role as an adipostatic factor is likely to be a secondary role acquired during the evolution of mammals.
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62
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Differential mobility spectrometry: a valuable technology for analyzing challenging biological samples. Bioanalysis 2016; 7:853-6. [PMID: 25932519 DOI: 10.4155/bio.15.14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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63
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Johnson TA, Mcleod MJ, Holyoak T. Utilization of Substrate Intrinsic Binding Energy for Conformational Change and Catalytic Function in Phosphoenolpyruvate Carboxykinase. Biochemistry 2016; 55:575-87. [PMID: 26709450 DOI: 10.1021/acs.biochem.5b01215] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Phosphoenolpyruvate carboxykinase (PEPCK) is an essential metabolic enzyme operating in the gluconeogenesis and glyceroneogenesis pathways. Previous work has demonstrated that the enzyme cycles between a catalytically inactive open state and a catalytically active closed state. The transition of the enzyme between these states requires the transition of several active site loops to shift from mobile, disordered structural elements to stable ordered states. The mechanism by which these disorder-order transitions are coupled to the ligation state of the active site however is not fully understood. To further investigate the mechanisms by which the mobility of the active site loops is coupled to enzymatic function and the transitioning of the enzyme between the two conformational states, we have conducted structural and functional studies of point mutants of E89. E89 is a proposed key member of the interaction network of mobile elements as it resides in the R-loop region of the enzyme active site. These new data demonstrate the importance of the R-loop in coordinating interactions between substrates at the OAA/PEP binding site and the mobile R- and Ω-loop domains. In turn, the studies more generally demonstrate the mechanisms by which the intrinsic ligand binding energy can be utilized in catalysis to drive unfavorable conformational changes, changes that are subsequently required for both optimal catalytic activity and fidelity.
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Affiliation(s)
- Troy A Johnson
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center , Kansas City, Kansas 66160, United States
| | - Matthew J Mcleod
- Department of Biology, University of Waterloo , Waterloo, ON N2L 3G1, Canada
| | - Todd Holyoak
- Department of Biology, University of Waterloo , Waterloo, ON N2L 3G1, Canada.,Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center , Kansas City, Kansas 66160, United States
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64
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Maciejak P, Szyndler J, Turzyńska D, Sobolewska A, Kołosowska K, Krząścik P, Płaźnik A. Is the interaction between fatty acids and tryptophan responsible for the efficacy of a ketogenic diet in epilepsy? The new hypothesis of action. Neuroscience 2016; 313:130-48. [DOI: 10.1016/j.neuroscience.2015.11.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 01/09/2023]
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65
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Regulation of Glucose Homeostasis by Glucocorticoids. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015. [PMID: 26215992 DOI: 10.1007/978-1-4939-2895-8_5] [Citation(s) in RCA: 353] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucocorticoids are steroid hormones that regulate multiple aspects of glucose homeostasis. Glucocorticoids promote gluconeogenesis in liver, whereas in skeletal muscle and white adipose tissue they decrease glucose uptake and utilization by antagonizing insulin response. Therefore, excess glucocorticoid exposure causes hyperglycemia and insulin resistance. Glucocorticoids also regulate glycogen metabolism. In liver, glucocorticoids increase glycogen storage, whereas in skeletal muscle they play a permissive role for catecholamine-induced glycogenolysis and/or inhibit insulin-stimulated glycogen synthesis. Moreover, glucocorticoids modulate the function of pancreatic α and β cells to regulate the secretion of glucagon and insulin, two hormones that play a pivotal role in the regulation of blood glucose levels. Overall, the major glucocorticoid effect on glucose homeostasis is to preserve plasma glucose for brain during stress, as transiently raising blood glucose is important to promote maximal brain function. In this chapter we will discuss the current understanding of the mechanisms underlying different aspects of glucocorticoid-regulated mammalian glucose homeostasis.
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66
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Schein V, Kucharski LC, Guerreiro PMG, Martins TL, Morgado I, Power DM, Canario AVM, da Silva RSM. Stanniocalcin 1 effects on the renal gluconeogenesis pathway in rat and fish. Mol Cell Endocrinol 2015; 414:1-8. [PMID: 26187698 DOI: 10.1016/j.mce.2015.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/03/2015] [Accepted: 07/10/2015] [Indexed: 11/16/2022]
Abstract
The mammalian kidney contributes significantly to glucose homeostasis through gluconeogenesis. Considering that stanniocalcin 1 (STC1) regulates ATP production, is synthesized and acts in different cell types of the nephron, the present study hypothesized that STC1 may be implicated in the regulation of gluconeogenesis in the vertebrate kidney. Human STC1 strongly reduced gluconeogenesis from (14)C-glutamine in rat renal medulla (MD) slices but not in renal cortex (CX), nor from (14)C-lactic acid. Total PEPCK activity was markedly reduced by hSTC1 in MD but not in CX. Pck2 (mitochondrial PEPCK isoform) was down-regulated by hSTC1 in MD but not in CX. In fish (Dicentrarchus labrax) kidney slices, both STC1-A and -B isoforms decreased gluconeogenesis from (14)C-acid lactic, while STC1-A increased gluconeogenesis from (14)C-glutamine. Overall, our results demonstrate a role for STC1 in the control of glucose synthesis via renal gluconeogenesis in mammals and suggest that it may have a similar role in teleost fishes.
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Affiliation(s)
- Vanessa Schein
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil; Pos-Graduate Program in Health Sciences, Department of Obstetrics and Gynecology, School of Medicine, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2400, 90035-003, Porto Alegre, RS, Brazil; CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
| | - Luiz C Kucharski
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
| | - Pedro M G Guerreiro
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Tiago Leal Martins
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
| | - Isabel Morgado
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Deborah M Power
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Adelino V M Canario
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Roselis S M da Silva
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
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67
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Brown LD, Rozance PJ, Bruce JL, Friedman JE, Hay WW, Wesolowski SR. Limited capacity for glucose oxidation in fetal sheep with intrauterine growth restriction. Am J Physiol Regul Integr Comp Physiol 2015. [PMID: 26224688 DOI: 10.1152/ajpregu.00197.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Intrauterine growth-restricted (IUGR) fetal sheep, produced by placental insufficiency, have lower oxygen concentrations, higher lactate concentrations, and increased hepatic glucose production that is resistant to suppression by insulin. We hypothesized that increased lactate production in the IUGR fetus results from reduced glucose oxidation, during basal and maximal insulin-stimulated conditions, and is used to support glucose production. To test this, studies were performed in late-gestation control (CON) and IUGR fetal sheep under basal and hyperinsulinemic-clamp conditions. The basal glucose oxidation rate was similar and increased by 30-40% during insulin clamp in CON and IUGR fetuses (P < 0.005). However, the fraction of glucose oxidized was 15% lower in IUGR fetuses during basal and insulin-clamp periods (P = 0.05). IUGR fetuses also had four-fold higher lactate concentrations (P < 0.001) and lower lactate uptake rates (P < 0.05). In IUGR fetal muscle and liver, mRNA expression of pyruvate dehydrogenase kinase (PDK4), an inhibitor of glucose oxidation, was increased over fourfold. In IUGR fetal liver, but not skeletal muscle, mRNA expression of lactate dehydrogenase A (LDHA) was increased nearly fivefold. Hepatic expression of the gluconeogenic genes, phosphoenolpyruvate carboxykinase (PCK)1, and PCK2, was correlated with expression of PDK4 and LDHA. Collectively, these in vivo and tissue data support limited capacity for glucose oxidation in the IUGR fetus via increased PDK4 in skeletal muscle and liver. We speculate that lactate production also is increased, which may supply carbon for glucose production in the IUGR fetal liver.
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Affiliation(s)
- Laura D Brown
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jennifer L Bruce
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jacob E Friedman
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - William W Hay
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Stephanie R Wesolowski
- Perinatal Research Center, Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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68
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DeFronzo RA, Ferrannini E, Groop L, Henry RR, Herman WH, Holst JJ, Hu FB, Kahn CR, Raz I, Shulman GI, Simonson DC, Testa MA, Weiss R. Type 2 diabetes mellitus. Nat Rev Dis Primers 2015; 1:15019. [PMID: 27189025 DOI: 10.1038/nrdp.2015.19] [Citation(s) in RCA: 1014] [Impact Index Per Article: 112.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is an expanding global health problem, closely linked to the epidemic of obesity. Individuals with T2DM are at high risk for both microvascular complications (including retinopathy, nephropathy and neuropathy) and macrovascular complications (such as cardiovascular comorbidities), owing to hyperglycaemia and individual components of the insulin resistance (metabolic) syndrome. Environmental factors (for example, obesity, an unhealthy diet and physical inactivity) and genetic factors contribute to the multiple pathophysiological disturbances that are responsible for impaired glucose homeostasis in T2DM. Insulin resistance and impaired insulin secretion remain the core defects in T2DM, but at least six other pathophysiological abnormalities contribute to the dysregulation of glucose metabolism. The multiple pathogenetic disturbances present in T2DM dictate that multiple antidiabetic agents, used in combination, will be required to maintain normoglycaemia. The treatment must not only be effective and safe but also improve the quality of life. Several novel medications are in development, but the greatest need is for agents that enhance insulin sensitivity, halt the progressive pancreatic β-cell failure that is characteristic of T2DM and prevent or reverse the microvascular complications. For an illustrated summary of this Primer, visit: http://go.nature.com/V2eGfN.
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Affiliation(s)
- Ralph A DeFronzo
- Diabetes Division, Department of Medicine, University of Texas Health Science Center, South Texas Veterans Health Care System and Texas Diabetes Institute, 701 S. Zarzamoro, San Antonio, Texas 78207, USA
| | | | - Leif Groop
- Department of Clinical Science Malmoe, Diabetes &Endocrinology, Lund University Diabetes Centre, Lund, Sweden
| | - Robert R Henry
- University of California, San Diego, Section of Diabetes, Endocrinology &Metabolism, Center for Metabolic Research, VA San Diego Healthcare System, San Diego, California, USA
| | | | | | - Frank B Hu
- Department of Nutrition, Harvard T.H. Chan School of Public Health and Department of Epidemiology, Harvard T.H. Chan School of Public Health and Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - C Ronald Kahn
- Harvard Medical School and Joslin Diabetes Center, Boston, Massachusetts, USA
| | - Itamar Raz
- Diabetes Unit, Division of Internal Medicine, Hadassah Hebrew University Hospital, Jerusalem, Israel
| | - Gerald I Shulman
- Howard Hughes Medical Institute and the Departments of Internal Medicine and Cellular &Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Donald C Simonson
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marcia A Testa
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Ram Weiss
- Department of Human Metabolism and Nutrition, Braun School of Public Health, Hebrew University, Jerusalem, Israel
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69
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Abstract
Adipose tissue is a complex, multicellular organ that profoundly influences the function of nearly all other organ systems through its diverse metabolite and adipokine secretome. Adipocytes are the primary cell type of adipose tissue and play a key role in maintaining energy homeostasis. The efficiency with which adipose tissue responds to whole-body energetic demands reflects the ability of adipocytes to adapt to an altered nutrient environment, and has profound systemic implications. Deciphering adipocyte cell biology is an important component of understanding how the aberrant physiology of expanding adipose tissue contributes to the metabolic dysregulation associated with obesity.
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Affiliation(s)
- Joseph M Rutkowski
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jennifer H Stern
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390 Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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70
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Bartok O, Teesalu M, Ashwall-Fluss R, Pandey V, Hanan M, Rovenko BM, Poukkula M, Havula E, Moussaieff A, Vodala S, Nahmias Y, Kadener S, Hietakangas V. The transcription factor Cabut coordinates energy metabolism and the circadian clock in response to sugar sensing. EMBO J 2015; 34:1538-53. [PMID: 25916830 DOI: 10.15252/embj.201591385] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/01/2015] [Indexed: 12/16/2022] Open
Abstract
Nutrient sensing pathways adjust metabolism and physiological functions in response to food intake. For example, sugar feeding promotes lipogenesis by activating glycolytic and lipogenic genes through the Mondo/ChREBP-Mlx transcription factor complex. Concomitantly, other metabolic routes are inhibited, but the mechanisms of transcriptional repression upon sugar sensing have remained elusive. Here, we characterize cabut (cbt), a transcription factor responsible for the repressive branch of the sugar sensing transcriptional network in Drosophila. We demonstrate that cbt is rapidly induced upon sugar feeding through direct regulation by Mondo-Mlx. We found that CBT represses several metabolic targets in response to sugar feeding, including both isoforms of phosphoenolpyruvate carboxykinase (pepck). Deregulation of pepck1 (CG17725) in mlx mutants underlies imbalance of glycerol and glucose metabolism as well as developmental lethality. Furthermore, we demonstrate that cbt provides a regulatory link between nutrient sensing and the circadian clock. Specifically, we show that a subset of genes regulated by the circadian clock are also targets of CBT. Moreover, perturbation of CBT levels leads to deregulation of the circadian transcriptome and circadian behavioral patterns.
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Affiliation(s)
- Osnat Bartok
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mari Teesalu
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Reut Ashwall-Fluss
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Varun Pandey
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mor Hanan
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bohdana M Rovenko
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Minna Poukkula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Essi Havula
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Arieh Moussaieff
- Department of Cell Biology, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sadanand Vodala
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA, USA
| | - Yaakov Nahmias
- Department of Cell Biology, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel Center for Bioengineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sebastian Kadener
- Biological Chemistry Department, Silberman Institute of Life Sciences The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ville Hietakangas
- Department of Biosciences, University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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71
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Chung ST, Hsia DS, Chacko SK, Rodriguez LM, Haymond MW. Increased gluconeogenesis in youth with newly diagnosed type 2 diabetes. Diabetologia 2015; 58:596-603. [PMID: 25447079 PMCID: PMC4323952 DOI: 10.1007/s00125-014-3455-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/03/2014] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS The role of increased gluconeogenesis as an important contributor to fasting hyperglycaemia at diabetes onset is not known. We evaluated the contribution of gluconeogenesis and glycogenolysis to fasting hyperglycaemia in newly diagnosed youths with type 2 diabetes following an overnight fast. METHODS Basal rates (μmol kg(FFM) (-1) min(-1)) of gluconeogenesis ((2)H2O), glycogenolysis and glycerol production ([(2)H5] glycerol) were measured in 18 adolescents (nine treatment naive diabetic and nine normal-glucose-tolerant obese adolescents). RESULTS Type 2 diabetes was associated with higher gluconeogenesis (9.2 ± 0.6 vs 7.0 ± 0.3 μmol kg(FFM) (-1) min(-1), p < 0.01), plasma fasting glucose (7.0 ± 0.6 vs 5.0 ± 0.2 mmol/l, p = 0.004) and insulin (300 ± 30 vs 126 ± 31 pmol/l, p = 0.001). Glucose production and glycogenolysis were similar between the groups (15.4 ± 0.3 vs 12.4 ± 1.4 μmol kg(FFM) (-1) min(-1), p = 0.06; and 6.2 ± 0.8 vs 5.3 ± 0.7 μmol kg(FFM) (-1) min(-1), p = 0.5, respectively). After controlling for differences in adiposity, gluconeogenesis, glycogenolysis and glucose production were higher in diabetic youth (p ≤ 0.02). Glycerol concentration (84 ± 6 vs 57 ± 6 μmol/l, p = 0.01) and glycerol production (5.0 ± 0.3 vs 3.6 ± 0.5 μmol kg(FFM) (-1) min(-1), p = 0.03) were 40% higher in youth with diabetes. The increased glycerol production could account for only ~1/3 of substrate needed for the increased gluconeogenesis in diabetic youth. CONCLUSION/INTERPRETATIONS Increased gluconeogenesis was a major contributor to fasting hyperglycaemia and hepatic insulin resistance in newly diagnosed untreated adolescents and was an early pathological feature of type 2 diabetes. Increased glycerol availability may represent a significant source of new carbon substrates for increased gluconeogenesis but would not account for all the carbons required to sustain the increased rates.
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Affiliation(s)
- Stephanie T Chung
- National Institute of Diabetes and Digestive and Kidney Diseases, NIH 10 Center Dr. Bld 10-CRC, RM 5-5740, MSC 1612, Bethesda, MD, 20892-1612, USA,
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72
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Cowens KR, Simpson S, Thomas WK, Carey GB. Polybrominated Diphenyl Ether (PBDE)-Induced Suppression of Phosphoenolpyruvate Carboxykinase (PEPCK) Decreases Hepatic Glyceroneogenesis and Disrupts Hepatic Lipid Homeostasis. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:1437-49. [PMID: 26692069 DOI: 10.1080/15287394.2015.1098580] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Polybrominated diphenyl ethers (PBDE) are a class of flame-retardant chemicals that leach into the environment and enter the human body. PBDE have been shown to suppress activity of phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme in fatty acid esterification via hepatic glyceroneogenesis. The objective of this investigation was to assess hepatic glyceroneogenesis and lipid metabolism in PBDE-treated rats. Male, weanling Wistar rats were gavaged daily for 28 d with 14 mg/kg body weight of either DE-71, a commercial PBDE mixture (treated), or corn oil (control). After a 48-h fast, rats were euthanized, blood was obtained, and livers were excised. Suppression of hepatic PEPCK activity by 40% was noted. Serum ketone bodies were elevated by 27% in treated rats compared to controls, while hepatic glyceroneogenesis as measured by (14)C-pyruvate incorporation into triglycerides was 41% lower in explants from treated rats compared to controls. Liver lipid content was 29% lower in treated animals compared to controls. Taken together, these findings suggest that DE-71-induced inhibition of hepatic PEPCK activity alters lipid metabolism by redirecting fatty acids away from esterification and storage toward ketone synthesis.
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Affiliation(s)
- Kylie R Cowens
- a Department of Molecular, Cellular, and Biomedical Sciences , University of New Hampshire , Durham , New Hampshire , USA
| | - Stephen Simpson
- a Department of Molecular, Cellular, and Biomedical Sciences , University of New Hampshire , Durham , New Hampshire , USA
| | - W Kelley Thomas
- a Department of Molecular, Cellular, and Biomedical Sciences , University of New Hampshire , Durham , New Hampshire , USA
| | - Gale B Carey
- a Department of Molecular, Cellular, and Biomedical Sciences , University of New Hampshire , Durham , New Hampshire , USA
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73
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Liang RY, Tu HF, Tan X, Yeh YS, Chueh PJ, Chuang SM. A gene signature for gold nanoparticle-exposed human cell lines. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00181h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A unique four-gene signature for AuNP exposure was identified using the cDNA microarray and evaluated by qPCR and biological assays in mammalian cell lines.
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Affiliation(s)
- Ruei-Yue Liang
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
| | - Hsin-Fang Tu
- Bachelor Program of Biotechnology
- National Chung Hsing University
- Taichung
- Taiwan
| | - Xiaotong Tan
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
| | - Yu-Shan Yeh
- Center for Measurement Standards (CMS)
- Industrial Technology Research Institute (ITRI)
- Hsinchu
- Taiwan
| | - Pin Ju Chueh
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
| | - Show-Mei Chuang
- Institute of Biomedical Sciences
- National Chung Hsing University
- Taichung
- Taiwan
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74
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Connor T, Martin SD, Howlett KF, McGee SL. Metabolic remodelling in obesity and type 2 diabetes: pathological or protective mechanisms in response to nutrient excess? Clin Exp Pharmacol Physiol 2014; 42:109-15. [DOI: 10.1111/1440-1681.12315] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 12/31/2022]
Affiliation(s)
- Timothy Connor
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
| | - Sheree D Martin
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
| | - Kirsten F Howlett
- Centre for Physical Activity and Nutrition; School of Exercise and Nutrition Sciences; Deakin University; Geelong Vic. Australia
| | - Sean L McGee
- Metabolic Remodelling Laboratory; Metabolic Research Unit; School of Medicine; Deakin University; Geelong Vic. Australia
- Division of Cell Signalling and Metabolism; Baker IDI Heart and Diabetes Institute; Melbourne Vic. Australia
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75
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McGill-Vargas LL, Johnson-Pais T, Johnson MC, Blanco CL. Developmental regulation of key gluconeogenic molecules in nonhuman primates. Physiol Rep 2014; 2:2/12/e12243. [PMID: 25524279 PMCID: PMC4332221 DOI: 10.14814/phy2.12243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Aberrant glucose regulation is common in preterm and full‐term neonates leading to short and long‐term morbidity/mortality; however, glucose metabolism in this population is understudied. The aim of this study was to investigate developmental differences in hepatic gluconeogenic pathways in fetal/newborn baboons. Fifteen fetal baboons were delivered at 125 day (d) gestational age (GA), 140d GA, and 175d GA (term = 185d GA) via cesarean section and sacrificed at birth. Term and healthy adult baboons were used as controls. Protein content and gene expression of key hepatic gluconeogenic molecules were measured: cytosolic and mitochondrial phosphoenolpyruvate carboxykinase (PEPCK‐C and PEPCK‐M), glucose‐6‐phosphatase‐alpha (G6Pase‐α), G6Pase‐β, fructose‐1,6‐bisphosphatase (FBPase), and forkhead box‐O1 (FOXO1). Protein content of PEPCK‐M increased with advancing gestation in fetal baboons (9.6 fold increase from 125d GA to 175d GA, P < 0.001). PEPCK‐C gene expression was consistent with these developmental differences. Phosphorylation of FOXO1 was significantly lower in preterm fetal baboons compared to adults, and gene expression of FOXO1 was lower in all neonates when compared to adults (10% and 62% of adults respectively, P < 0.05). The FOXO1 target gene G6Pase expression was higher in preterm animals compared to term animals. No significant differences were found in G6Pase‐α, G6Pase‐β, FOXO1, and FBPase during fetal development. In conclusion, significant developmental differences are found in hepatic gluconeogenic molecules in fetal and neonatal baboons, which may impact the responses to insulin during the neonatal period. Further studies under insulin‐stimulated conditions are required to understand the physiologic impact of these maturational differences. Significant developmental differences were found in several hepatic gluconeogenic molecules. In particular, phosphorylated FOXO1 was significantly reduced in the liver of premature fetal baboons compared to adults and may contribute the increased incidence of hyperglycemia seen in prematurity. In addition, PEPCK increased with advancing gestational age and may play a key role in glucose regulation during the newborn period.
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Affiliation(s)
- Lisa L McGill-Vargas
- Department of Pediatrics, Division of Neonatology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Teresa Johnson-Pais
- Department of Pediatrics, Division of Child Neurology, Developmental Pediatrics & Genetics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Marney C Johnson
- Department of Pediatrics, Division of Neonatology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Cynthia L Blanco
- Department of Pediatrics, Division of Neonatology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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76
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Kibbey RG, Choi CS, Lee HY, Cabrera O, Pongratz RL, Zhao X, Birkenfeld AL, Li C, Berggren PO, Stanley C, Shulman GI. Mitochondrial GTP insensitivity contributes to hypoglycemia in hyperinsulinemia hyperammonemia by inhibiting glucagon release. Diabetes 2014; 63:4218-29. [PMID: 25024374 PMCID: PMC4237996 DOI: 10.2337/db14-0783] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitochondrial GTP (mtGTP)-insensitive mutations in glutamate dehydrogenase (GDH(H454Y)) result in fasting and amino acid-induced hypoglycemia in hyperinsulinemia hyperammonemia (HI/HA). Surprisingly, hypoglycemia may occur in this disorder despite appropriately suppressed insulin. To better understand the islet-specific contribution, transgenic mice expressing the human activating mutation in β-cells (H454Y mice) were characterized in vivo. As in the humans with HI/HA, H454Y mice had fasting hypoglycemia, but plasma insulin concentrations were similar to the controls. Paradoxically, both glucose- and glutamine-stimulated insulin secretion were severely impaired in H454Y mice. Instead, lack of a glucagon response during hypoglycemic clamps identified impaired counterregulation. Moreover, both insulin and glucagon secretion were impaired in perifused islets. Acute pharmacologic inhibition of GDH restored both insulin and glucagon secretion and normalized glucose tolerance in vivo. These studies support the presence of an mtGTP-dependent signal generated via β-cell GDH that inhibits α-cells. As such, in children with activating GDH mutations of HI/HA, this insulin-independent glucagon suppression may contribute importantly to symptomatic hypoglycemia. The identification of a human mutation causing congenital hypoglucagonemic hypoglycemia highlights a central role of the mtGTP-GDH-glucagon axis in glucose homeostasis.
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Affiliation(s)
- Richard G Kibbey
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
| | - Cheol Soo Choi
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Hui-Young Lee
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Over Cabrera
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL Department of Molecular Medicine and Surgery, The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Rebecca L Pongratz
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Andreas L Birkenfeld
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT
| | - Changhong Li
- Division of Endocrinology, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Per-Olof Berggren
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL Department of Molecular Medicine and Surgery, The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Charles Stanley
- Division of Endocrinology, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
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77
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Méndez-Lucas A, Hyroššová P, Novellasdemunt L, Viñals F, Perales JC. Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) is a pro-survival, endoplasmic reticulum (ER) stress response gene involved in tumor cell adaptation to nutrient availability. J Biol Chem 2014; 289:22090-102. [PMID: 24973213 DOI: 10.1074/jbc.m114.566927] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M), encoded by the nuclear PCK2 gene, links TCA cycle intermediates and glycolytic pools through the conversion of mitochondrial oxaloacetate into phosphoenolpyruvate. In the liver PEPCK-M adjoins its profusely studied cytosolic isoform (PEPCK-C) potentiating gluconeogenesis and TCA flux. However, PEPCK-M is present in a variety of non-gluconeogenic tissues, including tumors of several origins. Despite its potential relevance to cancer metabolism, the mechanisms responsible for PCK2 gene regulation have not been elucidated. The present study demonstrates PEPCK-M overexpression in tumorigenic cells as well as the mechanism for the modulation of PCK2 abundance under several stress conditions. Amino acid limitation and ER stress inducers, conditions that activate the amino acid response (AAR) and the unfolded protein response (UPR), stimulate PCK2 gene transcription. Both the AAR and UPR lead to increased synthesis of ATF4, which mediates PCK2 transcriptional up-regulation through its binding to a putative ATF/CRE composite site within the PCK2 promoter functioning as an amino acid response element. In addition, activation of the GCN2-eIF2α-ATF4 and PERK-eIF2α-ATF4 signaling pathways are responsible for increased PEPCK-M levels. Finally, PEPCK-M knockdown using either siRNA or shRNA were sufficient to reduce MCF7 mammary carcinoma cell growth and increase cell death under glutamine deprivation or ER stress conditions. Our data demonstrate that this enzyme has a critical role in the survival program initiated upon stress and shed light on an unexpected and important role of mitochondrial PEPCK in cancer metabolism.
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Affiliation(s)
- Andrés Méndez-Lucas
- From the Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona E-08907, Spain
| | - Petra Hyroššová
- From the Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona E-08907, Spain
| | - Laura Novellasdemunt
- From the Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona E-08907, Spain
| | - Francesc Viñals
- From the Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona E-08907, Spain
| | - Jose C Perales
- From the Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona E-08907, Spain
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