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Luptak I, Shen M, He H, Hirshman MF, Musi N, Goodyear LJ, Yan J, Wakimoto H, Morita H, Arad M, Seidman CE, Seidman J, Ingwall JS, Balschi JA, Tian R. Aberrant activation of AMP-activated protein kinase remodels metabolic network in favor of cardiac glycogen storage. J Clin Invest 2007; 117:1432-9. [PMID: 17431505 PMCID: PMC1847536 DOI: 10.1172/jci30658] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 02/13/2007] [Indexed: 11/17/2022] Open
Abstract
AMP-activated protein kinase (AMPK) responds to impaired cellular energy status by stimulating substrate metabolism for ATP generation. Mutation of the gamma2 regulatory subunit of AMPK in humans renders the kinase insensitive to energy status and causes glycogen storage cardiomyopathy via unknown mechanisms. Using transgenic mice expressing one of the mutant gamma2 subunits (N488I) in the heart, we found that aberrant high activity of AMPK in the absence of energy deficit caused extensive remodeling of the substrate metabolism pathways to accommodate increases in both glucose uptake and fatty acid oxidation in the hearts of gamma2 mutant mice via distinct, yet synergistic mechanisms resulting in selective fuel storage as glycogen. Increased glucose entry in the gamma2 mutant mouse hearts was directed through the remodeled metabolic network toward glycogen synthesis and, at a substantially higher glycogen level, recycled through the glycogen pool to enter glycolysis. Thus, the metabolic consequences of chronic activation of AMPK in the absence of energy deficiency is distinct from those previously reported during stress conditions. These findings are of particular importance in considering AMPK as a target for the treatment of metabolic diseases.
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Affiliation(s)
- Ivan Luptak
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Mei Shen
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Huamei He
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Michael F. Hirshman
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Nicolas Musi
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Laurie J. Goodyear
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Jie Yan
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Hiroko Wakimoto
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Hiroyuki Morita
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Michael Arad
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Christine E. Seidman
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - J.G. Seidman
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Joanne S. Ingwall
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - James A. Balschi
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Rong Tian
- NMR Laboratory for Physiological Chemistry, Division of Cardiovascular Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Metabolism Unit, Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
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Marin S, Lee WN, Bassilian S, Lim S, Boros L, Centelles J, FERNáNDEZ-NOVELL J, Guinovart J, Cascante M. Dynamic profiling of the glucose metabolic network in fasted rat hepatocytes using [1,2-13C2]glucose. Biochem J 2004; 381:287-94. [PMID: 15032751 PMCID: PMC1133787 DOI: 10.1042/bj20031737] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 03/15/2004] [Accepted: 03/22/2004] [Indexed: 01/19/2023]
Abstract
Recent studies in metabolic profiling have underscored the importance of the concept of a metabolic network of pathways with special functional characteristics that differ from those of simple reaction sequences. The characterization of metabolic functions requires the simultaneous measurement of substrate fluxes of interconnecting pathways. Here we present a novel stable isotope method by which the forward and reverse fluxes of the futile cycles of the hepatic glucose metabolic network are simultaneously determined. Unlike previous radio-isotope methods, a single tracer [1,2-13C2]D-glucose and mass isotopomer analysis is used. Changes in fluxes of substrate cycles, in response to several gluconeogenic substrates, in isolated fasted hepatocytes from male Wistar rats were measured simultaneously. Incubation with these substrates resulted in a change in glucose-6-phosphatase/glucokinase and glycolytic/gluconeogenic flux ratios. Different net redistributions of intermediates in the glucose network were observed, resulting in distinct metabolic phenotypes of the fasted hepatocytes in response to each substrate condition. Our experimental observations show that the constraints of concentrations of shared intermediates, and enzyme kinetics of intersecting pathways of the metabolic network determine substrate redistribution throughout the network when it is perturbed. These results support the systems-biology notion that network analysis provides an integrated view of the physiological state. Interaction between metabolic intermediates and glycolytic/gluconeogenic pathways is a basic element of cross-talk in hepatocytes, and may explain some of the difficulties in genotype and phenotype correlation.
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Affiliation(s)
- Silvia Marin
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - W.-N. Paul Lee
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Sara Bassilian
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Shu Lim
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Laszlo G. Boros
- ‡Harbor-UCLA Research and Education Institute, UCLA School of Medicine, 1124 West Carson St. RB 1, Torrance, CA 90502, U.S.A
| | - Josep J. Centelles
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - Josep Maria FERNáNDEZ-NOVELL
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
| | - Joan J. Guinovart
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- §Institut de Recerca Biomèdica de Barcelona (IRBB), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
| | - Marta Cascante
- *Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Martí i Franquès 1, Barcelona 08028, Spain
- †Centre de Recerca en Química Teòrica (CeRQT), Parc Científic de Barcelona, Universitat de Barcelona, Barcelona 08028, Spain
- To whom correspondence should be addressed (e-mail )
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