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Schulze A, Tran C, Levandovskiy V, Patel V, Cortez MA. Systemic availability of guanidinoacetate affects GABAA receptor function and seizure threshold in GAMT deficient mice. Amino Acids 2016; 48:2041-7. [PMID: 26898547 DOI: 10.1007/s00726-016-2197-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/08/2016] [Indexed: 11/29/2022]
Abstract
Deficiency of guanidinoacetate methyltransferase (GAMT) causes creatine depletion and guanidinoacetate accumulation in brain with the latter deemed to be responsible for the severe seizure disorder seen in affected patients. We studied electrical brain activity and GABAA mediated mechanisms of B6J.Cg-Gamt(tm1Isb) mice. Electrocorticographic (ECoG) monitoring of pharmacological treatments with ornithine (5 % in drinking water for 5-18 days) and/or Picrotoxin (PTX) (a GABAA receptor antagonist) (1.5 mg/kg, I.P.) in Gamt(MUT) and Gamt(WT) groups [n = 3, mean age (SEM) = 6.9 (0.2) weeks]. Mice were fitted with two frontal and two parietal epidural electrodes under ketamine/xylazine anesthesia. Baseline and test recordings were performed for determination of seizure activity over a 2 h period. The ECoG baseline of Gamt(MUT) exhibited an abnormal monotonous cortical rhythm (7-8 Hz) with little variability during awake and sleep states compared to wild type recordings. Ornithine treatment and also PTX administration led to a relative normalization of the Gamt(MUT) ECoG phenotype. Gamt(WT) on PTX exhibited electro-behavioral seizures, whereas the Gamt(MUT) did not have PTX induced seizures at the same PTX dose. Gamt(MUT) treated with both ornithine and PTX did not show electro-behavioral seizures while ornithine elevated the PTX seizure threshold of Gamt(MUT) mice even further. These data demonstrate: (1) that there is expression of electrical seizure activity in this Gamt-deficient transgenic mouse strain, and (2) that the systemic availability of guanidinoacetate affects GABAA receptor function and seizure thresholds. These findings are directly and clinically relevant for patients with a creatine-deficiency syndrome due to genetic defects in GAMT and provide a rational basis for a combined ornithine/picrotoxin therapeutic intervention.
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Affiliation(s)
- A Schulze
- Program of Genetics and Genome Biology, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada. .,Department of Pediatrics, University of Toronto, Toronto, ON, Canada.
| | - C Tran
- Program of Genetics and Genome Biology, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.,Center for Molecular Diseases, Lausanne University Hospital, Lausanne, Switzerland
| | - V Levandovskiy
- Program of Genetics and Genome Biology, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
| | - V Patel
- Program of Genetics and Genome Biology, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
| | - M A Cortez
- Department of Pediatrics, University of Toronto, Toronto, ON, Canada.,Program of Brain and Behavior Neuroscience and Mental Health, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada
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Hanna-El-Daher L, Braissant O. Creatine synthesis and exchanges between brain cells: What can be learned from human creatine deficiencies and various experimental models? Amino Acids 2016; 48:1877-95. [PMID: 26861125 DOI: 10.1007/s00726-016-2189-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/27/2016] [Indexed: 12/11/2022]
Abstract
While it has long been thought that most of cerebral creatine is of peripheral origin, the last 20 years has provided evidence that the creatine synthetic pathway (AGAT and GAMT enzymes) is expressed in the brain together with the creatine transporter (SLC6A8). It has also been shown that SLC6A8 is expressed by microcapillary endothelial cells at the blood-brain barrier, but is absent from surrounding astrocytes, raising the concept that the blood-brain barrier has a limited permeability for peripheral creatine. The first creatine deficiency syndrome in humans was also discovered 20 years ago (GAMT deficiency), followed later by AGAT and SLC6A8 deficiencies, all three diseases being characterized by creatine deficiency in the CNS and essentially affecting the brain. By reviewing the numerous and latest experimental studies addressing creatine transport and synthesis in the CNS, as well as the clinical and biochemical characteristics of creatine-deficient patients, our aim was to delineate a clearer view of the roles of the blood-brain and blood-cerebrospinal fluid barriers in the transport of creatine and guanidinoacetate between periphery and CNS, and on the intracerebral synthesis and transport of creatine. This review also addresses the question of guanidinoacetate toxicity for brain cells, as probably found under GAMT deficiency.
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MESH Headings
- Amidinotransferases/deficiency
- Amidinotransferases/genetics
- Amidinotransferases/metabolism
- Amino Acid Metabolism, Inborn Errors/genetics
- Amino Acid Metabolism, Inborn Errors/metabolism
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Blood-Brain Barrier/metabolism
- Blood-Brain Barrier/pathology
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/metabolism
- Brain Diseases, Metabolic, Inborn/pathology
- Capillaries/metabolism
- Capillaries/pathology
- Creatine/biosynthesis
- Creatine/deficiency
- Creatine/genetics
- Creatine/metabolism
- Developmental Disabilities/genetics
- Developmental Disabilities/metabolism
- Developmental Disabilities/pathology
- Disease Models, Animal
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Guanidinoacetate N-Methyltransferase/deficiency
- Guanidinoacetate N-Methyltransferase/genetics
- Guanidinoacetate N-Methyltransferase/metabolism
- Humans
- Intellectual Disability/genetics
- Intellectual Disability/metabolism
- Intellectual Disability/pathology
- Language Development Disorders/genetics
- Language Development Disorders/metabolism
- Language Development Disorders/pathology
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/metabolism
- Mental Retardation, X-Linked/pathology
- Movement Disorders/congenital
- Movement Disorders/genetics
- Movement Disorders/metabolism
- Movement Disorders/pathology
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Plasma Membrane Neurotransmitter Transport Proteins/deficiency
- Plasma Membrane Neurotransmitter Transport Proteins/genetics
- Plasma Membrane Neurotransmitter Transport Proteins/metabolism
- Speech Disorders/genetics
- Speech Disorders/metabolism
- Speech Disorders/pathology
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Affiliation(s)
- Layane Hanna-El-Daher
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, 1011, Lausanne, Switzerland
| | - Olivier Braissant
- Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, 1011, Lausanne, Switzerland.
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53
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Xiao Y, Zhai Q, Wang G, Liu X, Zhao J, Tian F, Zhang H, Chen W. Metabolomics analysis reveals heavy metal copper-induced cytotoxicity in HT-29 human colon cancer cells. RSC Adv 2016. [DOI: 10.1039/c6ra09320e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
LC-MS based metabolomics analysis reveals heavy metal copper-induced cytotoxicity in a human intestinal cell line, HT-29.
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Affiliation(s)
- Yue Xiao
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Qixiao Zhai
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Gang Wang
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Xiaoming Liu
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Fengwei Tian
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology
- School of Food Science and Technology
- Jiangnan University
- Wuxi
- People's Republic of China
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Joncquel-Chevalier Curt M, Voicu PM, Fontaine M, Dessein AF, Porchet N, Mention-Mulliez K, Dobbelaere D, Soto-Ares G, Cheillan D, Vamecq J. Creatine biosynthesis and transport in health and disease. Biochimie 2015; 119:146-65. [DOI: 10.1016/j.biochi.2015.10.022] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/27/2015] [Indexed: 12/31/2022]
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55
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Yang SL, Xia JH, Zhang YY, Fan JG, Wang H, Yuan J, Zhao ZZ, Pan Q, Mu YL, Xin LL, Chen YX, Li K. Hyperinsulinemia shifted energy supply from glucose to ketone bodies in early nonalcoholic steatohepatitis from high-fat high-sucrose diet induced Bama minipigs. Sci Rep 2015; 5:13980. [PMID: 26358367 PMCID: PMC4566077 DOI: 10.1038/srep13980] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 08/12/2015] [Indexed: 02/06/2023] Open
Abstract
The minipig can serve as a good pharmacological model for human subjects. However, the long-term pathogenesis of high-calorie diet-induced metabolic syndromes, including NASH, has not been well described in minipigs. We examined the development of metabolic syndromes in Bama minipigs that were fed a high-fat, high-sucrose diet (HFHSD) for 23 months, by using histology and serum biochemistry and by profiling the gene expression patterns in the livers of HFHSD pigs compared to controls. The pathology findings revealed microvesicular steatosis, iron overload, arachidonic acid synthesis, lipid peroxidation, reduced antioxidant capacity, increased cellular damage, and inflammation in the liver. RNA-seq analysis revealed that 164 genes were differentially expressed between the livers of the HFHSD and control groups. The pathogenesis of early-stage NASH was characterized by hyperinsulinemia and by de novo synthesis of fatty acids and nascent triglycerides, which were deposited as lipid droplets in hepatocytes. Hyperinsulinemia shifted the energy supply from glucose to ketone bodies, and the high ketone body concentration induced the overexpression of cytochrome P450 2E1 (CYP2E1). The iron overload, CYP2E1 and alcohol dehydrogenase 4 overexpression promoted reactive oxygen species (ROS) production, which resulted in arachidonic and linoleic acid peroxidation and, in turn, led to malondialdehyde production and a cellular response to ROS-mediated DNA damage.
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Affiliation(s)
- Shu-lin Yang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Ji-han Xia
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Yuan-yuan Zhang
- College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Jian-gao Fan
- Department of Gastroenterology, Shanghai Key Laboratory of Children's Digestion and Nutrition, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, P.R. China
| | - Hua Wang
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, 230032, Anhui, P.R. China
| | - Jing Yuan
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China.,College of Animal Science, Yangtze University, Jinzhou, 434023, Hubei, P.R. China
| | - Zhan-zhao Zhao
- College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Qin Pan
- Department of Gastroenterology, Shanghai Key Laboratory of Children's Digestion and Nutrition, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200092, P.R. China
| | - Yu-lian Mu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Lei-lei Xin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Yao-xing Chen
- College of Veterinary Medicine, China Agricultural University, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
| | - Kui Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, No.2 Yuanmingyuan West Road, Beijing, 100193, P.R. China
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Kerksick CM, Roberts MD, Dalbo VJ, Sunderland KL. Intramuscular phosphagen status and the relationship to muscle performance across the age spectrum. Eur J Appl Physiol 2015; 116:115-27. [PMID: 26307531 DOI: 10.1007/s00421-015-3246-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 08/19/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To examine age-related differences in intramuscular concentrations of adenosine triphosphate (ATP), free creatine (FCr), phosphocreatine (PCr) and total creatine (TCr) and if these differences were related to muscle performance. METHODS Forty-two healthy, non-sedentary, males between 20 and 76 years provided muscle samples to determine [ATP], [FCr], [PCr], and [TCr]. Maximal strength and endurance were assessed and correlated with intramuscular variables. RESULTS Intramuscular [ATP] decreased by 13.5% (p = 0.013) in the older cohort (18.0 ± 0.6 mmol/kg dry wt) vs. the young cohort (20.8 ± 0.9 mmol/kg dry wt) and was significantly correlated to age (r = -0.38, p = 0.008). No other differences were observed between age groups for intramuscular [PCr], [FCr], [TCr], or [PCr]:[TCr] (p > 0.05). The older cohort consumed significantly less (p < 0.05) dietary protein when compared to the young cohort. Bivariate correlations were found for intramuscular [ATP] and lower body 1RM (r = 0.24, p = 0.066), leg press volume and free creatine (r = 0.325, p = 0.036) and leg press repetitions and free creatine (r = 0.373, p = 0.015). Partial correlations controlling for age eliminated the relationship between [ATP] and 1RM while intramuscular free creatine and leg press repetitions remained significant (p < 0.05) and leg press volume approached significance (p = 0.095). CONCLUSION These results expand upon previous observations indicative of age-related reductions in intramuscular [ATP] and dietary protein intake. The lack of change in other intramuscular PCr system markers are suggestive of dysfunctions at the mitochondrial level while the impact of neuromuscular changes, lean mass cross-sectional area and differences in physical activity are also important.
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Affiliation(s)
- Chad M Kerksick
- Department of Exercise Science, School of Sport, Recreation and Exercise Sciences, Lindenwood University, St. Charles, MO, 63301, USA.
| | | | - Vincent J Dalbo
- Clinical Biochemistry Laboratory, School of Medicine and Applied Sciences, Central Queensland University, Rockhampton, QLD, 4702, Australia
| | - Kyle L Sunderland
- Department of Exercise Science, High Point University, High Point, NC, 27262, USA
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57
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Cellular bioenergetics of guanidinoacetic acid: the role of mitochondria. J Bioenerg Biomembr 2015; 47:369-72. [PMID: 26255041 DOI: 10.1007/s10863-015-9619-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 07/31/2015] [Indexed: 10/23/2022]
Abstract
Guanidinoacetic acid (GAA) is a natural precursor of creatine, and a possible substrate for the creatine kinase (CK) enzyme system, serving as a creatine mimetic. Its direct role in cellular bioenergetics has been confirmed in several studies, however GAA utilization by CK seems to be a second-rate as compared to creatine, and compartment-dependent. Here we discuss various factors that might affect GAA use in high-energy phosphoryl transfer in the cytosol and mitochondria.
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58
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Sharideh H, Esmaeile Neia L, Zaghari M, Zhandi M, Akhlaghi A, Lotfi L. Effect of feeding guanidinoacetic acid and L-arginine on the fertility rate and sperm penetration in the perivitelline layer of aged broiler breeder hens. J Anim Physiol Anim Nutr (Berl) 2015. [DOI: 10.1111/jpn.12372] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- H. Sharideh
- Department of Animal Science; College of Agriculture and Natural Resources; University of Tehran; Karaj Iran
| | - L. Esmaeile Neia
- Department of Animal Science; College of Agriculture and Natural Resources; University of Tehran; Karaj Iran
| | - M. Zaghari
- Department of Animal Science; College of Agriculture and Natural Resources; University of Tehran; Karaj Iran
| | - M. Zhandi
- Department of Animal Science; College of Agriculture and Natural Resources; University of Tehran; Karaj Iran
| | - A. Akhlaghi
- Department of Animal Science; College of Agriculture; Shiraz University; Shiraz Iran
| | - L. Lotfi
- Department of Animal Science; College of Agriculture and Natural Resources; University of Tehran; Karaj Iran
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59
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Hanna-El-Daher L, Béard E, Henry H, Tenenbaum L, Braissant O. Mild guanidinoacetate increase under partial guanidinoacetate methyltransferase deficiency strongly affects brain cell development. Neurobiol Dis 2015; 79:14-27. [DOI: 10.1016/j.nbd.2015.03.029] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/27/2015] [Accepted: 03/31/2015] [Indexed: 11/15/2022] Open
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Biosynthesis of homoarginine (hArg) and asymmetric dimethylarginine (ADMA) from acutely and chronically administered free L-arginine in humans. Amino Acids 2015; 47:1893-908. [PMID: 26031828 DOI: 10.1007/s00726-015-2012-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/18/2015] [Indexed: 12/17/2022]
Abstract
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthesis, whereas L-arginine (Arg) and L-homoarginine (hArg) serve as substrates for NO synthesis. ADMA and other methylated arginines are generally believed to exclusively derive from guanidine (N (G))-methylated arginine residues in proteins by protein arginine methyltransferases (PRMTs) that use S-adenosylmethionine (SAM) as the methyl donor. L-Lysine is known for decades as a precursor for hArg, but only recent studies indicate that arginine:glycine amidinotransferase (AGAT) is responsible for the synthesis of hArg. AGAT catalyzes the formation of guanidinoacetate (GAA) that is methylated to creatine by guanidinoacetate methyltransferase (GAMT) which also uses SAM. The aim of the present study was to learn more about the mechanisms of ADMA and hArg formation in humans. Especially, we hypothesized that ADMA is produced by N (G)-methylation of free Arg in addition to the known PRMTs-involving mechanism. In knockout mouse models of AGAT- and GAMT-deficiency, we investigated the contribution of these enzymes to hArg synthesis. Arg infusion (0.5 g/kg, 30 min) in children (n = 11) and ingestion of high-fat protein meals by overweight men (n = 10) were used to study acute effects on ADMA and hArg synthesis. Daily Arg ingestion (10 g) or placebo for 3 or 6 months by patients suffering from peripheral arterial occlusive disease (PAOD, n = 20) or coronary artery disease (CAD, n = 30) was used to study chronic effects of Arg on ADMA synthesis. Mass spectrometric methods were used to measure all biochemical parameters in plasma and urine samples. In mice, AGAT but not GAMT was found to contribute to plasma hArg, while ADMA synthesis was independent of AGAT and GAMT. Arg infusion acutely increased plasma Arg, hArg and ADMA concentrations, but decreased the plasma hArg/ADMA ratio. High-fat protein meals acutely increased plasma Arg, hArg, ADMA concentrations, as well as the plasma hArg/ADMA ratio. In the PAOD and CAD studies, plasma Arg concentration increased in the verum compared to the placebo groups. Plasma ADMA concentration increased only in the PAOD patients who received Arg. Our study suggests that in humans a minor fraction of free Arg is rapidly metabolized to ADMA and hArg. In mice, GAMT and N (G)-methyltransferases contribute to ADMA and hArg synthesis from Arg, whereas AGAT is involved in the synthesis of hArg but not of ADMA. The underlying biochemical mechanisms remain still elusive.
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Sheedy JR, Gooley PR, Nahid A, Tull DL, McConville MJ, Kukuljan S, Nowson CA, Daly RM, Ebeling PR. 1H-NMR analysis of the human urinary metabolome in response to an 18-month multi-component exercise program and calcium–vitamin-D3supplementation in older men. Appl Physiol Nutr Metab 2014; 39:1294-304. [DOI: 10.1139/apnm-2014-0060] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The musculoskeletal benefits of calcium and vitamin-D3supplementation and exercise have been extensively studied, but the effect on metabolism remains contentious. Urine samples were analyzed by1H-NMR spectroscopy from participants recruited for an 18-month, randomized controlled trial of a multi-component exercise program and calcium and vitamin-D3fortified milk consumption. It was shown previously that no increase in musculoskeletal composition was observed for participants assigned to the calcium and vitamin-D3intervention, but exercise resulted in increased bone mineral density, total lean body mass, and muscle strength. Retrospective metabolomics analysis of urine samples from patients involved in this study revealed no distinct changes in the urinary metabolome in response to the calcium and vitamin-D3intervention, but significant changes followed the exercise intervention, notably a reduction in creatinine and an increase in choline, guanidinoacetate, and hypoxanthine (p < 0.001, fold change > 1.5). These metabolites are intrinsically involved in anaerobic ATP synthesis, intracellular buffering, and methyl-balance regulation. The exercise intervention had a marked effect on the urine metabolome and markers of muscle turnover but none of these metabolites were obvious markers of bone turnover. Measurement of specific urinary exercise biomarkers may provide a basis for monitoring performance and metabolic response to exercise regimes.
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Affiliation(s)
- John R. Sheedy
- Department of Medicine, NorthWest Academic Centre, Sunshine Hospital, The University of Melbourne, Furlong Road, St Albans, Victoria, Australia, 3021
- Metabolomics Australia, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia, 3010
- Department of Zoology, The University of Melbourne, Parkville, Victoria, Australia, 3010
| | - Paul R. Gooley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia, 3010
| | - Amsha Nahid
- Monash University, Department of Physiology, Clayton Campus, Victoria, Australia, 3800
| | - Dedreia L. Tull
- Metabolomics Australia, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia, 3010
| | - Malcolm J. McConville
- Metabolomics Australia, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia, 3010
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia, 3010
| | - Sonja Kukuljan
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia, 3125
| | - Caryl A. Nowson
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia, 3125
| | - Robin M. Daly
- Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia, 3125
| | - Peter R. Ebeling
- Department of Medicine, NorthWest Academic Centre, Sunshine Hospital, The University of Melbourne, Furlong Road, St Albans, Victoria, Australia, 3021
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Aksentijević D, Zervou S, Faller KME, McAndrew DJ, Schneider JE, Neubauer S, Lygate CA. Myocardial creatine levels do not influence response to acute oxidative stress in isolated perfused heart. PLoS One 2014; 9:e109021. [PMID: 25272153 PMCID: PMC4182806 DOI: 10.1371/journal.pone.0109021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/01/2014] [Indexed: 01/01/2023] Open
Abstract
Background Multiple studies suggest creatine mediates anti-oxidant activity in addition to its established role in cellular energy metabolism. The functional significance for the heart has yet to be established, but antioxidant activity could contribute to the cardioprotective effect of creatine in ischaemia/reperfusion injury. Objectives To determine whether intracellular creatine levels influence responses to acute reactive oxygen species (ROS) exposure in the intact beating heart. We hypothesised that mice with elevated creatine due to over-expression of the creatine transporter (CrT-OE) would be relatively protected, while mice with creatine-deficiency (GAMT KO) would fare worse. Methods and Results CrT-OE mice were pre-selected for creatine levels 20–100% above wild-type using invivo1H–MRS. Hearts were perfused in isovolumic Langendorff mode and cardiac function monitored throughout. After 20 min equilibration, hearts were perfused with either H2O2 0.5 µM (30 min), or the anti-neoplastic drug doxorubicin 15 µM (100 min). Protein carbonylation, creatine kinase isoenzyme activities and phospho-PKCδ expression were quantified in perfused hearts as markers of oxidative damage and apoptotic signalling. Wild-type hearts responded to ROS challenge with a profound decline in contractile function that was ameliorated by co-administration of catalase or dexrazoxane as positive controls. In contrast, the functional deterioration in CrT-OE and GAMT KO hearts was indistinguishable from wild-type controls, as was the extent of oxidative damage and apoptosis. Exogenous creatine supplementation also failed to protect hearts from doxorubicin-induced dysfunction. Conclusions Intracellular creatine levels do not influence the response to acute ROS challenge in the intact beating heart, arguing against creatine exerting (patho-)physiologically relevant anti-oxidant activity.
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Affiliation(s)
- Dunja Aksentijević
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Sevasti Zervou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Kiterie M. E. Faller
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Debra J. McAndrew
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Jurgen E. Schneider
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Craig A. Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Baroncelli L, Alessandrì MG, Tola J, Putignano E, Migliore M, Amendola E, Gross C, Leuzzi V, Cioni G, Pizzorusso T. A novel mouse model of creatine transporter deficiency. F1000Res 2014; 3:228. [PMID: 25485098 PMCID: PMC4243761 DOI: 10.12688/f1000research.5369.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/25/2014] [Indexed: 12/29/2022] Open
Abstract
Mutations in the creatine (Cr) transporter (CrT) gene lead to cerebral creatine deficiency syndrome-1 (CCDS1), an X-linked metabolic disorder characterized by cerebral Cr deficiency causing intellectual disability, seizures, movement and behavioral disturbances, language and speech impairment ( OMIM #300352). CCDS1 is still an untreatable pathology that can be very invalidating for patients and caregivers. Only two murine models of CCDS1, one of which is an ubiquitous knockout mouse, are currently available to study the possible mechanisms underlying the pathologic phenotype of CCDS1 and to develop therapeutic strategies. Given the importance of validating phenotypes and efficacy of promising treatments in more than one mouse model we have generated a new murine model of CCDS1 obtained by ubiquitous deletion of 5-7 exons in the
Slc6a8 gene. We showed a remarkable Cr depletion in the murine brain tissues and cognitive defects, thus resembling the key features of human CCDS1. These results confirm that CCDS1 can be well modeled in mice. This CrT
−/y murine model will provide a new tool for increasing the relevance of preclinical studies to the human disease.
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Affiliation(s)
- Laura Baroncelli
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Maria Grazia Alessandrì
- Department of Developmental Neuroscience, IRCCS Stella Maris Scientific Institute, Calambrone (Pisa), I-56128, Italy
| | - Jonida Tola
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Elena Putignano
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Martina Migliore
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy
| | - Elena Amendola
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo (Roma), I-00015, Italy
| | - Cornelius Gross
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo (Roma), I-00015, Italy
| | - Vincenzo Leuzzi
- Department of Paediatrics, Child Neurology and Psychiatry, Sapienza University of Rome, Rome, I-00185, Italy
| | - Giovanni Cioni
- Department of Developmental Neuroscience, IRCCS Stella Maris Scientific Institute, Calambrone (Pisa), I-56128, Italy ; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, I-56126, Italy
| | - Tommaso Pizzorusso
- Institute of Neuroscience, National Research Council (CNR), Pisa, I-56124, Italy ; Department of Neuroscience, Psychology, Drug Research and Child Health NEUROFARBA, University of Florence, Florence, I-50135, Italy
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64
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Birkedal R, Laasmaa M, Vendelin M. The location of energetic compartments affects energetic communication in cardiomyocytes. Front Physiol 2014; 5:376. [PMID: 25324784 PMCID: PMC4178378 DOI: 10.3389/fphys.2014.00376] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/10/2014] [Indexed: 01/08/2023] Open
Abstract
The heart relies on accurate regulation of mitochondrial energy supply to match energy demand. The main regulators are Ca2+ and feedback of ADP and Pi. Regulation via feedback has intrigued for decades. First, the heart exhibits a remarkable metabolic stability. Second, diffusion of ADP and other molecules is restricted specifically in heart and red muscle, where a fast feedback is needed the most. To explain the regulation by feedback, compartmentalization must be taken into account. Experiments and theoretical approaches suggest that cardiomyocyte energetic compartmentalization is elaborate with barriers obstructing diffusion in the cytosol and at the level of the mitochondrial outer membrane (MOM). A recent study suggests the barriers are organized in a lattice with dimensions in agreement with those of intracellular structures. Here, we discuss the possible location of these barriers. The more plausible scenario includes a barrier at the level of MOM. Much research has focused on how the permeability of MOM itself is regulated, and the importance of the creatine kinase system to facilitate energetic communication. We hypothesize that at least part of the diffusion restriction at the MOM level is not by MOM itself, but due to the close physical association between the sarcoplasmic reticulum (SR) and mitochondria. This will explain why animals with a disabled creatine kinase system exhibit rather mild phenotype modifications. Mitochondria are hubs of energetics, but also ROS production and signaling. The close association between SR and mitochondria may form a diffusion barrier to ADP added outside a permeabilized cardiomyocyte. But in vivo, it is the structural basis for the mitochondrial-SR coupling that is crucial for the regulation of mitochondrial Ca2+-transients to regulate energetics, and for avoiding Ca2+-overload and irreversible opening of the mitochondrial permeability transition pore.
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Affiliation(s)
- Rikke Birkedal
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology Tallinn, Estonia
| | - Martin Laasmaa
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology Tallinn, Estonia
| | - Marko Vendelin
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology Tallinn, Estonia
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Borchel A, Verleih M, Rebl A, Kühn C, Goldammer T. Creatine metabolism differs between mammals and rainbow trout (Oncorhynchus mykiss). SPRINGERPLUS 2014; 3:510. [PMID: 25279302 PMCID: PMC4167887 DOI: 10.1186/2193-1801-3-510] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 11/10/2022]
Abstract
Creatine plays an important role in the cell as an energy buffer. As the energy system is a basic element of the organism it may possibly contribute to differences between rainbow trout strains selected for the traits growth and robustness, respectively. The cDNA sequences of creatine-related genes encoding glycine amidinotransferase (GATM), guanidinoacetate N-methyltransferase (GAMT), creatine kinase muscle-type (CKM) and creatine transporter 1 (CT1, encoded by gene solute carrier family 6, member 8 (SLC6A8)) were characterized in rainbow trout. Transcripts of the respective genes were quantified in kidney, liver, brain and skeletal muscle in both trout strains that had been acclimated to different temperatures. Several differences between the compared trout strains were found as well as between temperatures indicating that the energy system may contribute to differences between both strains. In addition to that, the expression data showed clear differences between the creatine system in rainbow trout and mammals, as the spatial distribution of the enzyme-encoding gene expression was clearly different from the patterns described for mammals. In rainbow trout, creatine synthesis seems to take place to a big extent in the skeletal muscle.
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Affiliation(s)
- Andreas Borchel
- />Leibniz-Institut für Nutztierbiologie (FBN), Institut für Genombiologie, Wilhelm-Stahl-Allee 2, Dummerstorf, 18196 Germany
| | - Marieke Verleih
- />Leibniz-Institut für Nutztierbiologie (FBN), Institut für Genombiologie, Wilhelm-Stahl-Allee 2, Dummerstorf, 18196 Germany
| | - Alexander Rebl
- />Leibniz-Institut für Nutztierbiologie (FBN), Institut für Genombiologie, Wilhelm-Stahl-Allee 2, Dummerstorf, 18196 Germany
| | - Carsten Kühn
- />Landesforschungsanstalt für Landwirtschaft und Fischerei Mecklenburg-Vorpommern (LFA M-V), Institut für Fischerei, Born, Germany
| | - Tom Goldammer
- />Leibniz-Institut für Nutztierbiologie (FBN), Institut für Genombiologie, Wilhelm-Stahl-Allee 2, Dummerstorf, 18196 Germany
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66
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Tran C, Yazdanpanah M, Kyriakopoulou L, Levandovskiy V, Zahid H, Naufer A, Isbrandt D, Schulze A. Stable isotope dilution microquantification of creatine metabolites in plasma, whole blood and dried blood spots for pharmacological studies in mouse models of creatine deficiency. Clin Chim Acta 2014; 436:160-8. [DOI: 10.1016/j.cca.2014.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 05/04/2014] [Accepted: 05/06/2014] [Indexed: 10/25/2022]
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van de Kamp JM, Mancini GM, Salomons GS. X-linked creatine transporter deficiency: clinical aspects and pathophysiology. J Inherit Metab Dis 2014; 37:715-33. [PMID: 24789340 DOI: 10.1007/s10545-014-9713-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 12/22/2022]
Abstract
Creatine transporter deficiency was discovered in 2001 as an X-linked cause of intellectual disability characterized by cerebral creatine deficiency. This review describes the current knowledge regarding creatine metabolism, the creatine transporter and the clinical aspects of creatine transporter deficiency. The condition mainly affects the brain while other creatine requiring organs, such as the muscles, are relatively spared. Recent studies have provided strong evidence that creatine synthesis also occurs in the brain, leading to the intriguing question of why cerebral creatine is deficient in creatine transporter deficiency. The possible mechanisms explaining the cerebral creatine deficiency are discussed. The creatine transporter knockout mouse provides a good model to study the disease. Over the past years several treatment options have been explored but no treatment has been proven effective. Understanding the pathogenesis of creatine transporter deficiency is of paramount importance in the development of an effective treatment.
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MESH Headings
- Amino Acid Metabolism, Inborn Errors/diagnosis
- Amino Acid Metabolism, Inborn Errors/drug therapy
- Amino Acid Metabolism, Inborn Errors/genetics
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Brain Diseases, Metabolic, Inborn/complications
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/physiopathology
- Creatine/deficiency
- Creatine/genetics
- Genetic Diseases, X-Linked/genetics
- Humans
- Intellectual Disability/etiology
- Intellectual Disability/genetics
- Membrane Transport Proteins/deficiency
- Membrane Transport Proteins/genetics
- Mental Retardation, X-Linked/complications
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/physiopathology
- Mice
- Plasma Membrane Neurotransmitter Transport Proteins/deficiency
- Plasma Membrane Neurotransmitter Transport Proteins/genetics
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Affiliation(s)
- Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands,
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Saks V, Schlattner U, Tokarska-Schlattner M, Wallimann T, Bagur R, Zorman S, Pelosse M, Santos PD, Boucher F, Kaambre T, Guzun R. Systems Level Regulation of Cardiac Energy Fluxes Via Metabolic Cycles: Role of Creatine, Phosphotransfer Pathways, and AMPK Signaling. SYSTEMS BIOLOGY OF METABOLIC AND SIGNALING NETWORKS 2014. [DOI: 10.1007/978-3-642-38505-6_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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69
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Choe CU, Atzler D, Wild PS, Carter AM, Böger RH, Ojeda F, Simova O, Stockebrand M, Lackner K, Nabuurs C, Marescau B, Streichert T, Müller C, Lüneburg N, De Deyn PP, Benndorf RA, Baldus S, Gerloff C, Blankenberg S, Heerschap A, Grant PJ, Magnus T, Zeller T, Isbrandt D, Schwedhelm E. Homoarginine Levels Are Regulated by
l
-Arginine:Glycine Amidinotransferase and Affect Stroke Outcome. Circulation 2013; 128:1451-61. [DOI: 10.1161/circulationaha.112.000580] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Chi-un Choe
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Dorothee Atzler
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Philipp S. Wild
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Angela M. Carter
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Rainer H. Böger
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Francisco Ojeda
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Olga Simova
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Malte Stockebrand
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Karl Lackner
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Christine Nabuurs
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Bart Marescau
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Thomas Streichert
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Christian Müller
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Nicole Lüneburg
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Peter P. De Deyn
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Ralf A. Benndorf
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Stephan Baldus
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Christian Gerloff
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Stefan Blankenberg
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Arend Heerschap
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Peter J. Grant
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Tim Magnus
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Tanja Zeller
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Dirk Isbrandt
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
| | - Edzard Schwedhelm
- From the Departments of Neurology (C.C., O.S., C.G., T.M.), Experimental Neuropediatrics (C.C., M.S., D.I.), Department of Clinical Pharmacology and Toxicology (D.A., R.H.B., N.L., R.A.B., E.S.), and German Center for Cardiovascular Research (D.A., P.S.W., R.H.B., S.B., T.Z., E.S.), Clinic for General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany (F.O., C.M., S. Baldus, S. Blankenberg, T.Z.); Department of Clinical Chemistry, University Medical Center
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Zervou S, Ray T, Sahgal N, Sebag-Montefiore L, Cross R, Medway DJ, Ostrowski PJ, Neubauer S, Lygate CA. A role for thioredoxin-interacting protein (Txnip) in cellular creatine homeostasis. Am J Physiol Endocrinol Metab 2013; 305:E263-70. [PMID: 23715727 PMCID: PMC3725544 DOI: 10.1152/ajpendo.00637.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Creatine is important for energy metabolism, yet excitable cells such as cardiomyocytes do not synthesize creatine and rely on uptake via a specific membrane creatine transporter (CrT; SLC6A8). This process is tightly controlled with downregulation of CrT upon continued exposure to high creatine via mechanisms that are poorly understood. Our aim was to identify candidate endogenous CrT inhibitors. In 3T3 cells overexpressing the CrT, creatine uptake plateaued at 3 h in response to 5 mM creatine but peaked 33% higher (P < 0.01) in the presence of cycloheximide, suggesting CrT regulation depends on new protein synthesis. Global gene expression analysis identified thioredoxin-interacting protein (Txnip) as the only significantly upregulated gene (by 46%) under these conditions (P = 0.036), subsequently verified independently at mRNA and protein levels. There was no change in Txnip expression with exposure to 5 mM taurine, confirming a specific response to creatine rather than osmotic stress. Small-interfering RNA against Txnip prevented Txnip upregulation in response to high creatine, maintained normal levels of creatine uptake, and prevented downregulation of CrT mRNA. These findings were relevant to the in vivo heart since creatine-deficient mice showed 39.71% lower levels of Txnip mRNA, whereas mice overexpressing the CrT had 57.6% higher Txnip mRNA levels and 28.7% higher protein expression compared with wild types (mean myocardial creatine concentration 124 and 74 nmol/mg protein, respectively). In conclusion, we have identified Txnip as a novel negative regulator of creatine levels in vitro and in vivo, responsible for mediating substrate feedback inhibition and a potential target for modulating creatine homeostasis.
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Affiliation(s)
- Sevasti Zervou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Headington, Oxford, United Kingdom.
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71
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Stockebrand M, Sauter K, Neu A, Isbrandt D, Choe CU. Differential regulation of AMPK activation in leptin- and creatine-deficient mice. FASEB J 2013; 27:4147-56. [PMID: 23825223 DOI: 10.1096/fj.12-225136] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AMP-activated protein kinase (AMPK) is a key sensor and regulator of energy homeostasis. Previously, we demonstrated that intracellular energy depletion by L-arginine:glycine amidinotransferase (AGAT) deficiency resulted in AMPK activation and protected from metabolic syndrome. In the present study, we show tissue-specific leptin dependence of AMPK activation by energy depletion. We investigated leptin-dependent AMPK regulation in AGAT- and leptin-deficient (d/d ob/ob) mice. Like ob/ob mice, but unlike d/d mice, d/d ob/ob mice were obese and glucose intolerant. Therefore, leptin is a prerequisite for resistance to metabolic syndrome in AGAT-deficient mice. Quantitative Western blots revealed a 4-fold increase in AMPK activation in skeletal muscle of d/d ob/ob mice (P<0.001). However, AMPK activation was absent in white adipose tissue (WAT) and liver. Compared with blood glucose levels in ob/ob mice, fasting levels were still reduced and therefore did not show leptin dependence (wild-type, 79.4±3.9 mg/dl; d/d, 68.4±3.2 mg/dl; P<0.05). In ob/ob mice and wild-type mice, 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), in combination with leptin, augmented glucose tolerance compared with AICAR alone, whereas no improvement was found under conditions of high-fat-diet feeding. These findings reveal a previously unknown synergistic AMPK activation by leptin and intracellular energy depletion, suggesting that AMPK activation can be therapeutically effective in metabolic syndrome only if leptin sensitivity is preserved.
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Affiliation(s)
- Malte Stockebrand
- 1Experimental Neuropediatrics, Center for Molecular Neurobiology and Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
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72
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Snow RJ. AGAT knockout mice provide an opportunity to titrate tissue creatine content. J Physiol 2013; 591:393. [PMID: 23322291 DOI: 10.1113/jphysiol.2012.247924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rodney J Snow
- Centre for Physical Activity and Nutrition,School of Exercise and Nutrition Sciences, Deakin University, Burwood, 3125, Victoria,
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73
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Branovets J, Sepp M, Kotlyarova S, Jepihhina N, Sokolova N, Aksentijevic D, Lygate CA, Neubauer S, Vendelin M, Birkedal R. Unchanged mitochondrial organization and compartmentation of high-energy phosphates in creatine-deficient GAMT-/- mouse hearts. Am J Physiol Heart Circ Physiol 2013; 305:H506-20. [PMID: 23792673 DOI: 10.1152/ajpheart.00919.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Disruption of the creatine kinase (CK) system in hearts of CK-deficient mice leads to changes in the ultrastructure and regulation of mitochondrial respiration. We expected to see similar changes in creatine-deficient mice, which lack the enzyme guanidinoacetate methyltransferase (GAMT) to produce creatine. The aim of this study was to characterize the changes in cardiomyocyte mitochondrial organization, regulation of respiration, and intracellular compartmentation associated with GAMT deficiency. Three-dimensional mitochondrial organization was assessed by confocal microscopy. On populations of permeabilized cardiomyocytes, we recorded ADP and ATP kinetics of respiration, competition between mitochondria and pyruvate kinase for ADP produced by ATPases, ADP kinetics of endogenous pyruvate kinase, and ATP kinetics of ATPases. These data were analyzed by mathematical models to estimate intracellular compartmentation. Quantitative analysis of morphological and kinetic data as well as derived model fits showed no difference between GAMT-deficient and wild-type mice. We conclude that inactivation of the CK system by GAMT deficiency does not alter mitochondrial organization and intracellular compartmentation in relaxed cardiomyocytes. Thus, our results suggest that the healthy heart is able to preserve cardiac function at a basal level in the absence of CK-facilitated energy transfer without compromising intracellular organization and the regulation of mitochondrial energy homeostasis. This raises questions on the importance of the CK system as a spatial energy buffer in unstressed cardiomyocytes.
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Affiliation(s)
- Jelena Branovets
- Laboratory of Systems Biology, Institute of Cybernetics, Tallinn University of Technology, Tallinn, Estonia; and
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74
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van de Kamp JM, Betsalel OT, Mercimek-Mahmutoglu S, Abulhoul L, Grünewald S, Anselm I, Azzouz H, Bratkovic D, de Brouwer A, Hamel B, Kleefstra T, Yntema H, Campistol J, Vilaseca MA, Cheillan D, D’Hooghe M, Diogo L, Garcia P, Valongo C, Fonseca M, Frints S, Wilcken B, von der Haar S, Meijers-Heijboer HE, Hofstede F, Johnson D, Kant SG, Lion-Francois L, Pitelet G, Longo N, Maat-Kievit JA, Monteiro JP, Munnich A, Muntau AC, Nassogne MC, Osaka H, Ounap K, Pinard JM, Quijano-Roy S, Poggenburg I, Poplawski N, Abdul-Rahman O, Ribes A, Arias A, Yaplito-Lee J, Schulze A, Schwartz CE, Schwenger S, Soares G, Sznajer Y, Valayannopoulos V, Van Esch H, Waltz S, Wamelink MMC, Pouwels PJW, Errami A, van der Knaap MS, Jakobs C, Mancini GM, Salomons GS. Phenotype and genotype in 101 males with X-linked creatine transporter deficiency. J Med Genet 2013; 50:463-72. [DOI: 10.1136/jmedgenet-2013-101658] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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75
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Lygate CA, Aksentijevic D, Dawson D, ten Hove M, Phillips D, de Bono JP, Medway DJ, Sebag-Montefiore L, Hunyor I, Channon KM, Clarke K, Zervou S, Watkins H, Balaban RS, Neubauer S. Living without creatine: unchanged exercise capacity and response to chronic myocardial infarction in creatine-deficient mice. Circ Res 2013; 112:945-55. [PMID: 23325497 DOI: 10.1161/circresaha.112.300725] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Creatine is thought to be involved in the spatial and temporal buffering of ATP in energetic organs such as heart and skeletal muscle. Creatine depletion affects force generation during maximal stimulation, while reduced levels of myocardial creatine are a hallmark of the failing heart, leading to the widely held view that creatine is important at high workloads and under conditions of pathological stress. OBJECTIVE We therefore hypothesised that the consequences of creatine-deficiency in mice would be impaired running capacity, and exacerbation of heart failure following myocardial infarction. METHODS AND RESULTS Surprisingly, mice with whole-body creatine deficiency due to knockout of the biosynthetic enzyme (guanidinoacetate N-methyltransferase [GAMT]) voluntarily ran just as fast and as far as controls (>10 km/night) and performed the same level of work when tested to exhaustion on a treadmill. Furthermore, survival following myocardial infarction was not altered, nor was subsequent left ventricular (LV) remodelling and development of chronic heart failure exacerbated, as measured by 3D-echocardiography and invasive hemodynamics. These findings could not be accounted for by compensatory adaptations, with no differences detected between WT and GAMT(-/-) proteomes. Alternative phosphotransfer mechanisms were explored; adenylate kinase activity was unaltered, and although GAMT(-/-) hearts accumulated the creatine precursor guanidinoacetate, this had negligible energy-transfer activity, while mitochondria retained near normal function. CONCLUSIONS Creatine-deficient mice show unaltered maximal exercise capacity and response to chronic myocardial infarction, and no obvious metabolic adaptations. Our results question the paradigm that creatine is essential for high workload and chronic stress responses in heart and skeletal muscle.
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Affiliation(s)
- Craig A Lygate
- Department of Cardiovascular Medicine, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, UK.
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76
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Leuzzi V, Mastrangelo M, Battini R, Cioni G. Inborn errors of creatine metabolism and epilepsy. Epilepsia 2012; 54:217-27. [DOI: 10.1111/epi.12020] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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77
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Nabuurs CI, Choe CU, Veltien A, Kan HE, van Loon LJC, Rodenburg RJT, Matschke J, Wieringa B, Kemp GJ, Isbrandt D, Heerschap A. Disturbed energy metabolism and muscular dystrophy caused by pure creatine deficiency are reversible by creatine intake. J Physiol 2012; 591:571-92. [PMID: 23129796 DOI: 10.1113/jphysiol.2012.241760] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Creatine (Cr) plays an important role in muscle energy homeostasis by its participation in the ATP-phosphocreatine phosphoryl exchange reaction mediated by creatine kinase. Given that the consequences of Cr depletion are incompletely understood, we assessed the morphological, metabolic and functional consequences of systemic depletion on skeletal muscle in a mouse model with deficiency of l-arginine:glycine amidinotransferase (AGAT(-/-)), which catalyses the first step of Cr biosynthesis. In vivo magnetic resonance spectroscopy showed a near-complete absence of Cr and phosphocreatine in resting hindlimb muscle of AGAT(-/-) mice. Compared with wild-type, the inorganic phosphate/β-ATP ratio was increased fourfold, while ATP levels were reduced by nearly half. Activities of proton-pumping respiratory chain enzymes were reduced, whereas F(1)F(0)-ATPase activity and overall mitochondrial content were increased. The Cr-deficient AGAT(-/-) mice had a reduced grip strength and suffered from severe muscle atrophy. Electron microscopy revealed increased amounts of intramyocellular lipid droplets and crystal formation within mitochondria of AGAT(-/-) muscle fibres. Ischaemia resulted in exacerbation of the decrease of pH and increased glycolytic ATP synthesis. Oral Cr administration led to rapid accumulation in skeletal muscle (faster than in brain) and reversed all the muscle abnormalities, revealing that the condition of the AGAT(-/-) mice can be switched between Cr deficient and normal simply by dietary manipulation. Systemic creatine depletion results in mitochondrial dysfunction and intracellular energy deficiency, as well as structural and physiological abnormalities. The consequences of AGAT deficiency are more pronounced than those of muscle-specific creatine kinase deficiency, which suggests a multifaceted involvement of creatine in muscle energy homeostasis in addition to its role in the phosphocreatine-creatine kinase system.
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Affiliation(s)
- C I Nabuurs
- Radiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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78
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Choe CU, Nabuurs C, Stockebrand MC, Neu A, Nunes P, Morellini F, Sauter K, Schillemeit S, Hermans-Borgmeyer I, Marescau B, Heerschap A, Isbrandt D. L-arginine:glycine amidinotransferase deficiency protects from metabolic syndrome. Hum Mol Genet 2012; 22:110-23. [PMID: 23026748 DOI: 10.1093/hmg/dds407] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phosphorylated creatine (Cr) serves as an energy buffer for ATP replenishment in organs with highly fluctuating energy demand. The central role of Cr in the brain and muscle is emphasized by severe neurometabolic disorders caused by Cr deficiency. Common symptoms of inborn errors of creatine synthesis or distribution include mental retardation and muscular weakness. Human mutations in l-arginine:glycine amidinotransferase (AGAT), the first enzyme of Cr synthesis, lead to severely reduced Cr and guanidinoacetate (GuA) levels. Here, we report the generation and metabolic characterization of AGAT-deficient mice that are devoid of Cr and its precursor GuA. AGAT-deficient mice exhibited decreased fat deposition, attenuated gluconeogenesis, reduced cholesterol levels and enhanced glucose tolerance. Furthermore, Cr deficiency completely protected from the development of metabolic syndrome caused by diet-induced obesity. Biochemical analyses revealed the chronic Cr-dependent activation of AMP-activated protein kinase (AMPK), which stimulates catabolic pathways in metabolically relevant tissues such as the brain, skeletal muscle, adipose tissue and liver, suggesting a mechanism underlying the metabolic phenotype. In summary, our results show marked metabolic effects of Cr deficiency via the chronic activation of AMPK in a first animal model of AGAT deficiency. In addition to insights into metabolic changes in Cr deficiency syndromes, our genetic model reveals a novel mechanism as a potential treatment option for obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Chi-un Choe
- Experimental Neuropediatrics, Center for Molecular Neurobiology and Department of Pediatrics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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79
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Pérusse L, Rankinen T, Zuberi A, Chagnon YC, Weisnagel SJ, Argyropoulos G, Walts B, Snyder EE, Bouchard C. The Human Obesity Gene Map: The 2004 Update. ACTA ACUST UNITED AC 2012; 13:381-490. [PMID: 15833932 DOI: 10.1038/oby.2005.50] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.
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Affiliation(s)
- Louis Pérusse
- Division of Kinesiology, Department of Social and Preventive Medicine, Faculty of Medicine, Laval University, Sainte-Foy, Québec, Canada
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80
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Brocca L, Cannavino J, Coletto L, Biolo G, Sandri M, Bottinelli R, Pellegrino MA. The time course of the adaptations of human muscle proteome to bed rest and the underlying mechanisms. J Physiol 2012; 590:5211-30. [PMID: 22848045 DOI: 10.1113/jphysiol.2012.240267] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In order to get a comprehensive picture of the complex adaptations of human skeletal muscle to disuse and further the understanding of the underlying mechanisms, we participated in two bed rest campaigns, one lasting 35 days and one 24 days. In the first bed rest (BR) campaign, myofibrillar proteins, metabolic enzymes and antioxidant defence systems were found to be down-regulated both post-8 days and post-35 days BR by proteomic analysis of vastus lateralis muscle samples from nine subjects. Such profound alterations occurred early (post-8 days BR), before disuse atrophy developed, and persisted through BR (post-35 days BR). To understand the mechanisms underlying the protein adaptations observed, muscle biopsies from the second bed rest campaign (nine subjects) were used to evaluate the adaptations of master controllers of the balance between muscle protein breakdown and muscle protein synthesis (MuRF-1 and atrogin-1; Akt and p70S6K), of autophagy (Beclin-1, p62, LC3, bnip3, cathepsin-L), of expression of antioxidant defence systems (NRF2) and of energy metabolism (PGC-1α, SREBP-1, AMPK). The results indicate that: (i) redox imbalance and remodelling of muscle proteome occur early and persist through BR; (ii) impaired energy metabolism is an early and persistent phenomenon comprising both the oxidative and glycolytic one; (iii) although both major catabolic systems, ubiquitin proteasome and autophagy, could contribute to the progression of atrophy late into BR, a decreased protein synthesis cannot be ruled out; (iv) a decreased PGC-1α, with the concurrence of SREBP-1 up-regulation, is a likely trigger of metabolic impairment, whereas the AMPK pathway is unaltered.
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Affiliation(s)
- Lorenza Brocca
- Department of Molecular Medicine, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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81
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Lygate CA, Medway DJ, Ostrowski PJ, Aksentijevic D, Sebag-Montefiore L, Hunyor I, Zervou S, Schneider JE, Neubauer S. Chronic creatine kinase deficiency eventually leads to congestive heart failure, but severity is dependent on genetic background, gender and age. Basic Res Cardiol 2012; 107:276. [PMID: 22760499 PMCID: PMC3442167 DOI: 10.1007/s00395-012-0276-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/02/2012] [Accepted: 06/13/2012] [Indexed: 11/22/2022]
Abstract
The creatine kinase (CK) energy transport and buffering system supports cardiac function at times of high demand and is impaired in the failing heart. Mice deficient in muscle- and mitochondrial-CK (M/Mt-CK−/−) have previously been described, but exhibit an unexpectedly mild phenotype of compensated left ventricular (LV) hypertrophy. We hypothesised that heart failure would develop with age and performed echocardiography and LV haemodynamics at 1 year. Since all previous studies have utilised mice with a mixed genetic background, we backcrossed for >10 generations on to C57BL/6, and repeated the in vivo investigations. Male M/Mt-CK−/− mice on the mixed genetic background developed congestive heart failure as evidenced by significantly elevated end-diastolic pressure, impaired contractility, LV dilatation, hypertrophy and pulmonary congestion. Female mice were less severely affected, only showing trends for these parameters. After backcrossing, M/Mt-CK−/− mice had LV dysfunction consisting of impaired isovolumetric pressure changes and reduced contractile reserve, but did not develop congestive heart failure. Body weight was lower in knockout mice as a consequence of reduced total body fat. LV weight was not significantly elevated in relation to other internal organs and gene expression of LVH markers was normal, suggesting an absence of hypertrophy. In conclusion, the consequences of CK deficiency are highly dependent on genetic modifiers, gender and age. However, the observation that a primary defect in CK can, under the right conditions, result in heart failure suggests that impaired CK activity in the failing heart could contribute to disease progression.
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Affiliation(s)
- Craig A Lygate
- Department of Cardiovascular Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK.
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82
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Braissant O. Creatine and guanidinoacetate transport at blood-brain and blood-cerebrospinal fluid barriers. J Inherit Metab Dis 2012; 35:655-64. [PMID: 22252611 DOI: 10.1007/s10545-011-9433-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/22/2011] [Accepted: 11/30/2011] [Indexed: 10/14/2022]
Abstract
While it was thought that most of cerebral creatine is of peripheral origin, AGAT and GAMT are well expressed in CNS where brain cells synthesize creatine. While the creatine transporter SLC6A8 is expressed by microcapillary endothelial cells (MCEC) at blood-brain barrier (BBB), it is absent from their surrounding astrocytes. This raised the concept that BBB has a limited permeability for peripheral creatine, and that the brain supplies a part of its creatine by endogenous synthesis. This review brings together the latest data on creatine and guanidinoacetate transport through BBB and blood-CSF barrier (BCSFB) with the clinical evidence of AGAT-, GAMT- and SLC6A8-deficient patients, in order to delineate a clearer view on the roles of BBB and BCSFB in the transport of creatine and guanidinoacetate between periphery and CNS, and on brain synthesis and transport of creatine. It shows that in physiological conditions, creatine is taken up by CNS from periphery through SLC6A8 at BBB, but in limited amounts, and that CNS also needs its own creatine synthesis. No uptake of guanidinoacetate from periphery occurs at BBB except under GAMT deficiency, but a net exit of guanidinoacetate seems to occur from CSF to blood at BCSFB, predominantly through the taurine transporter TauT.
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Affiliation(s)
- Olivier Braissant
- Inborn Errors of Metabolism, Service of Biomedicine, Lausanne University Hospital, Avenue Pierre-Decker 2, CI 02/33, CH-1011, Lausanne, Switzerland.
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83
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Tachikawa M, Ikeda S, Fujinawa J, Hirose S, Akanuma SI, Hosoya KI. γ-Aminobutyric acid transporter 2 mediates the hepatic uptake of guanidinoacetate, the creatine biosynthetic precursor, in rats. PLoS One 2012; 7:e32557. [PMID: 22384273 PMCID: PMC3288109 DOI: 10.1371/journal.pone.0032557] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Accepted: 02/01/2012] [Indexed: 12/14/2022] Open
Abstract
Guanidinoacetic acid (GAA) is the biosynthetic precursor of creatine which is involved in storage and transmission of phosphate-bound energy. Hepatocytes readily convert GAA to creatine, raising the possibility that the active uptake of GAA by hepatocytes is a regulatory factor. The purpose of this study is to investigate and identify the transporter responsible for GAA uptake by hepatocytes. The characteristics of [(14)C]GAA uptake by hepatocytes were elucidated using the in vivo liver uptake method, freshly isolated rat hepatocytes, an expression system of Xenopus laevis oocytes, gene knockdown, and an immunohistochemical technique. In vivo injection of [(14)C]GAA into the rat femoral vein and portal vein results in the rapid uptake of [(14)C]GAA by the liver. The uptake was markedly inhibited by γ-aminobutyric acid (GABA) and nipecotinic acid, an inhibitor of GABA transporters (GATs). The characteristics of Na(+)- and Cl(-)-dependent [(14)C]GAA uptake by freshly isolated rat hepatocytes were consistent with those of GAT2. The Km value of the GAA uptake (134 µM) was close to that of GAT2-mediated GAA transport (78.9 µM). GABA caused a marked inhibition with an IC(50) value of 8.81 µM. The [(14)C]GAA uptake exhibited a significant reduction corresponding to the reduction in GAT2 protein expression. GAT2 was localized on the sinusoidal membrane of the hepatocytes predominantly in the periportal region. This distribution pattern was consistent with that of the creatine biosynthetic enzyme, S-adenosylmethionine:guanidinoacetate N-methyltransferase. GAT2 makes a major contribution to the sinusoidal GAA uptake by periportal hepatocytes, thus regulating creatine biosynthesis in the liver.
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Affiliation(s)
- Masanori Tachikawa
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Saori Ikeda
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Jun Fujinawa
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shirou Hirose
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shin-ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Ken-ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- * E-mail:
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84
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Ruiz-Aracama A, Peijnenburg A, Kleinjans J, Jennen D, van Delft J, Hellfrisch C, Lommen A. An untargeted multi-technique metabolomics approach to studying intracellular metabolites of HepG2 cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. BMC Genomics 2011; 12:251. [PMID: 21599895 PMCID: PMC3141663 DOI: 10.1186/1471-2164-12-251] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Accepted: 05/20/2011] [Indexed: 01/14/2023] Open
Abstract
Background In vitro cell systems together with omics methods represent promising alternatives to conventional animal models for toxicity testing. Transcriptomic and proteomic approaches have been widely applied in vitro but relatively few studies have used metabolomics. Therefore, the goal of the present study was to develop an untargeted methodology for performing reproducible metabolomics on in vitro systems. The human liver cell line HepG2, and the well-known hepatotoxic and non-genotoxic carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), were used as the in vitro model system and model toxicant, respectively. Results The study focused on the analysis of intracellular metabolites using NMR, LC-MS and GC-MS, with emphasis on the reproducibility and repeatability of the data. State of the art pre-processing and alignment tools and multivariate statistics were used to detect significantly altered levels of metabolites after exposing HepG2 cells to TCDD. Several metabolites identified using databases, literature and LC-nanomate-Orbitrap analysis were affected by the treatment. The observed changes in metabolite levels are discussed in relation to the reported effects of TCDD. Conclusions Untargeted profiling of the polar and apolar metabolites of in vitro cultured HepG2 cells is a valid approach to studying the effects of TCDD on the cell metabolome. The approach described in this research demonstrates that highly reproducible experiments and correct normalization of the datasets are essential for obtaining reliable results. The effects of TCDD on HepG2 cells reported herein are in agreement with previous studies and serve to validate the procedures used in the present work.
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Affiliation(s)
- Ainhoa Ruiz-Aracama
- RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen, The Netherlands.
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85
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Braissant O, Henry H, Béard E, Uldry J. Creatine deficiency syndromes and the importance of creatine synthesis in the brain. Amino Acids 2011; 40:1315-24. [DOI: 10.1007/s00726-011-0852-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 11/25/2010] [Indexed: 10/18/2022]
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86
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Tachikawa M, Hosoya KI. Transport characteristics of guanidino compounds at the blood-brain barrier and blood-cerebrospinal fluid barrier: relevance to neural disorders. Fluids Barriers CNS 2011; 8:13. [PMID: 21352605 PMCID: PMC3058069 DOI: 10.1186/2045-8118-8-13] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 02/28/2011] [Indexed: 12/24/2022] Open
Abstract
Guanidino compounds (GCs), such as creatine, phosphocreatine, guanidinoacetic acid, creatinine, methylguanidine, guanidinosuccinic acid, γ-guanidinobutyric acid, β-guanidinopropionic acid, guanidinoethane sulfonic acid and α-guanidinoglutaric acid, are present in the mammalian brain. Although creatine and phosphocreatine play important roles in energy homeostasis in the brain, accumulation of GCs may induce epileptic discharges and convulsions. This review focuses on how physiologically important and/or neurotoxic GCs are distributed in the brain under physiological and pathological conditions. Transporters for GCs at the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCSFB) have emerged as substantial contributors to GCs distribution in the brain. Creatine transporter (CRT/solute carrier (SLC) 6A8) expressed at the BBB regulates creatine concentration in the brain, and represents a major pathway for supply of creatine from the circulating blood to the brain. CRT may be a key factor facilitating blood-to-brain guanidinoacetate transport in patients deficient in S-adenosylmethionine:guanidinoacetate N-methyltransferase, the creatine biosynthetic enzyme, resulting in cerebral accumulation of guanidinoacetate. CRT, taurine transporter (TauT/SLC6A6) and organic cation transporter (OCT3/SLC22A3) expressed at the BCSFB are involved in guanidinoacetic acid or creatinine efflux transport from CSF. Interestingly, BBB efflux transport of GCs, including guanidinoacetate and creatinine, is negligible, though the BBB has a variety of efflux transport systems for synthetic precursors of GCs, such as amino acids and neurotransmitters. Instead, the BCSFB functions as a major cerebral clearance system for GCs. In conclusion, transport of GCs at the BBB and BCSFB appears to be the key determinant of the cerebral levels of GCs, and changes in the transport characteristics may cause the abnormal distribution of GCs in the brain seen in patients with certain neurological disorders.
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Affiliation(s)
- Masanori Tachikawa
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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87
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Longo N, Ardon O, Vanzo R, Schwartz E, Pasquali M. Disorders of creatine transport and metabolism. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2011; 157C:72-8. [PMID: 21308988 DOI: 10.1002/ajmg.c.30292] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Creatine is a nitrogen containing compound that serves as an energy shuttle between the mitochondrial sites of ATP production and the cytosol where ATP is utilized. There are two known disorders of creatine synthesis (both transmitted as autosomal recessive traits: arginine: glycine amidinotransferase (AGAT) deficiency; OMIM 602360; and guanidinoacetate methyltransferase (GAMT) deficiency (OMIM 601240)) and one disorder of creatine transport (X-linked recessive SLC6A8 creatine transporter deficiency (OMIM 300036)). All these disorders are characterized by brain creatine deficiency, detectable by magnetic resonance spectroscopy. Affected patients can have mental retardation, hypotonia, autism or behavioral problems and seizures. The diagnosis of these conditions relies on the measurement of plasma and urine creatine and guanidinoacetate. Creatine levels in plasma are reduced in both creatine synthesis defects and guanidinoacetate is increased in GAMT deficiency. The urine creatine/creatinine ratio is elevated in creatine transporter deficiency with normal plasma levels of creatine and guanidinoacetate. The diagnosis is confirmed in all cases by DNA testing or functional studies. Defects of creatine biosynthesis are treated with creatine supplements and, in GAMT deficiency, with ornithine and dietary restriction of arginine through limitation of protein intake. No causal therapy is yet available for creatine transporter deficiency and supplementation with the guanidinoacetate precursors arginine and glycine is being explored. The excellent response to therapy of early identified patients with GAMT or AGAT deficiency candidates these condition for inclusion in newborn screening programs.
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Affiliation(s)
- Nicola Longo
- Division of Medical Genetics, University of Utah, Salt Lake City, 84132, USA.
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88
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Béard E, Braissant O. Synthesis and transport of creatine in the CNS: importance for cerebral functions. J Neurochem 2010; 115:297-313. [DOI: 10.1111/j.1471-4159.2010.06935.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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89
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Braissant O, Béard E, Torrent C, Henry H. Dissociation of AGAT, GAMT and SLC6A8 in CNS: Relevance to creatine deficiency syndromes. Neurobiol Dis 2010; 37:423-33. [DOI: 10.1016/j.nbd.2009.10.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 10/15/2009] [Accepted: 10/22/2009] [Indexed: 10/20/2022] Open
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90
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Deignan JL, De Deyn PP, Cederbaum SD, Fuchshuber A, Roth B, Gsell W, Marescau B. Guanidino compound levels in blood, cerebrospinal fluid, and post-mortem brain material of patients with argininemia. Mol Genet Metab 2010; 100 Suppl 1:S31-6. [PMID: 20176499 DOI: 10.1016/j.ymgme.2010.01.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 01/13/2010] [Accepted: 01/13/2010] [Indexed: 10/19/2022]
Abstract
The paucity of hyperammonemic crises together with spasticity, only seen in human arginase I deficient patients and not in patients with other urea cycle disorders, forces a search for candidates other than ammonia to associate with the pathophysiology and symptomatology. Therefore, we determined arginine together with some catabolites of arginine in blood and cerebrospinal fluid of these patients as well as in extremely rare post-mortem brain material of two patients with argininemia. The levels of alpha-keto-delta-guanidinovaleric acid, argininic acid and alpha-N-acetylarginine correlate with the arginine levels in blood and cerebrospinal fluid of patients with imposed or spontaneous protein restriction. The levels in blood are higher than the upper limit of normal in all studied patients. In addition to the highly increased levels of these same compounds in blood of a child with argininemia, the increase of guanidinoacetic acid, 24h before death, is remarkable. However, the manifest increases of these studied catabolites of arginine are not seen in post-mortem brain material of the same pediatric patient. Otherwise a clear increase of guanidinoacetic acid in post-mortem brain material of an adult patient was shown. A similar, comparable increase of homoarginine in both studied post-mortem brain materials is observed. Therefore the study of the pathobiochemistry of arginine in argininemia must be completed in the future by the determination of the end catabolites of the nitric oxide and agmatine biosynthesis pathways in the knockouts as well as in the patients to evaluate their role, together with the here studied catabolites, as candidates for association with pathophysiology and symptomatology.
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Affiliation(s)
- Joshua L Deignan
- Department of Pathology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
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91
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Braissant O. Ammonia toxicity to the brain: effects on creatine metabolism and transport and protective roles of creatine. Mol Genet Metab 2010; 100 Suppl 1:S53-8. [PMID: 20227315 DOI: 10.1016/j.ymgme.2010.02.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 02/08/2010] [Indexed: 11/17/2022]
Abstract
Hyperammonemia can provoke irreversible damage to the developing brain, with the formation of cortical atrophy, ventricular enlargement, demyelination or gray and white matter hypodensities. Among the various pathogenic mechanisms involved, alterations in cerebral energy have been demonstrated. In particular, we could show that ammonia exposure generates a secondary deficiency in creatine in brain cells, by altering the brain expression and activity of the genes allowing creatine synthesis (AGAT and GAMT) and transport (SLC6A8). On the other hand, it is known that creatine administration can exert protective effects in various neurodegenerative processes. We could also show that creatine co-treatment under ammonia exposure can protect developing brain cells from some of the deleterious effects of ammonia, in particular axonal growth impairment. This article focuses on the effects of ammonia exposure on creatine metabolism and transport in developing brain cells, and on the potential neuroprotective properties of creatine in the brain exposed to ammonium.
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Affiliation(s)
- Olivier Braissant
- Inborn Errors of Metabolism, Clinical Chemistry Laboratory, Center Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
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92
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van Driel LMJW, Eijkemans MJC, de Jonge R, de Vries JHM, van Meurs JBJ, Steegers EAP, Steegers-Theunissen RPM. Body mass index is an important determinant of methylation biomarkers in women of reproductive ages. J Nutr 2009; 139:2315-21. [PMID: 19812220 DOI: 10.3945/jn.109.109710] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
B vitamin deficiencies lead to moderate hyperhomocysteinemia, which has been associated with health and disease. However, concomitant derangements in cellular methylation, reflected by altered plasma S-adenosylmethionine (SAM) or S-adenosylhomocysteine (SAH) concentrations, may be the primary cause. Therefore, we identified determinants of homocysteine, SAM, and SAH concentrations in 336 women, aged 20-48 y, as part of a large study focusing on risk factors for reproductive disorders. Blood was obtained to determine plasma SAM, SAH, and total homocysteine (tHcy), serum vitamin B-12 and folate, RBC folate concentrations, and the related single nucleotide polymorphisms 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C > T and 1298A > C, methionine synthase reductase (MTRR) 66A > G, and nicotinamide N-methyltransferase IVS1-151G > A. Questionnaires provided information on demographics, lifestyles, and nutrient intakes. Correlation coefficients were calculated and multivariable associations were assessed with a general linear model. Serum folate was positively correlated with SAM concentrations (r = 0.159; P = 0.004). Folate and vitamin B-12 were not correlated with SAH concentrations or the SAM:SAH ratio but were inversely correlated with tHcy concentrations (serum folate r = -0.324; RBC folate r = -0.294; vitamin B-12 r = -0.307; P < 0.01). From the multivariable analysis, BMI was the strongest determinant of SAM (standardized beta = 19.145; P < 0.001) and SAH concentrations (standardized beta = 3.241; P = 0.010). MTHFR 677TT (standardized beta = 0.195; P = 0.001), B vitamin supplement use (standardized beta = -0.156; P < 0.001) and dietary protein intake (standardized beta = -0.011; P < 0.001) were the strongest determinants of tHcy concentrations. Thus, the determinants of SAM and SAH differ from those of tHcy concentrations. Given that BMI was a strong determinant of SAM concentrations, it should be included in future studies on cellular methylation.
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Affiliation(s)
- Lydi M J W van Driel
- Department of Obstetrics and Gynecology, Division of Obstetrics and Prenatal Medicine, Erasmus Medical Center, University Medical Centre, Rotterdam, The Netherlands
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93
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Ide T, Brown-Endres L, Chu K, Ongusaha PP, Ohtsuka T, El-Deiry WS, Aaronson SA, Lee SW. GAMT, a p53-inducible modulator of apoptosis, is critical for the adaptive response to nutrient stress. Mol Cell 2009; 36:379-92. [PMID: 19917247 PMCID: PMC2779531 DOI: 10.1016/j.molcel.2009.09.031] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 07/11/2009] [Accepted: 09/02/2009] [Indexed: 01/25/2023]
Abstract
The p53 tumor suppressor protein has a well-established role in cell-fate decision-making processes. However, recent discoveries indicate that p53 has a non-tumor-suppressive role. Here we identify guanidinoacetate methyltransferase (GAMT), an enzyme involved in creatine synthesis, as a p53 target gene and a key downstream effector of adaptive response to nutrient stress. We show that GAMT is not only involved in p53-dependent apoptosis in response to genotoxic stress but is important for apoptosis induced by glucose deprivation. Additionally, p53-->GAMT upregulates fatty acid oxidation (FAO) induced by glucose starvation, utilizing this pathway as an alternate ATP-generating energy source. These results highlight that p53-dependent regulation of GAMT allows cells to maintain energy levels sufficient to undergo apoptosis or survival under conditions of nutrient stress. The p53-->GAMT pathway represents a new link between cellular stress responses and processes of creatine synthesis and FAO, demonstrating a further role of p53 in cellular metabolism.
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Affiliation(s)
- Takao Ide
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Lauren Brown-Endres
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Kiki Chu
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Pat P. Ongusaha
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Takao Ohtsuka
- Department of Surgery, Saga University Faculty of Medicine, Saga, Japan
| | - Wafik S. El-Deiry
- Department of Medicine, The Abramson Comprehensive Cancer Center, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Stuart A. Aaronson
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY, USA
| | - Sam W. Lee
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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94
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Tachikawa M, Kasai Y, Yokoyama R, Fujinawa J, Ganapathy V, Terasaki T, Hosoya KI. The blood-brain barrier transport and cerebral distribution of guanidinoacetate in rats: involvement of creatine and taurine transporters. J Neurochem 2009; 111:499-509. [DOI: 10.1111/j.1471-4159.2009.06332.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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95
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Abstract
In the early 1930s, Banting and Best, the discoverers of insulin, found that choline could prevent the development of fatty liver disease (steatosis) in pancreatectomized dogs treated with insulin. Later work indicated that in rats and mice, diets deficient in labile methyl groups (choline, methionine, betaine, folate) produced fatty liver and that long-term administration of diets deficient in choline and methionine also caused hepatocellular carcinoma. These experiments not only linked steatosis and diabetes but also provided evidence, for the first time, of the importance of labile methyl group balance to maintain normal liver function. This conclusion is now amply supported by the observation of mice devoid of key enzymes of methionine and folate metabolism and in patients with severe deficiencies in these enzymes. Moreover, treatments with various methionine metabolites in experimental animal models of liver disease show hepatoprotective properties.
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Affiliation(s)
- José M Mato
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (ciberhed), Technology Park of Bizkaia, 48160 Derio, Bizkaia, Spain.
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96
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Heerschap A, Kan HE, Nabuurs CIHC, Renema WK, Isbrandt D, Wieringa B. In vivo magnetic resonance spectroscopy of transgenic mice with altered expression of guanidinoacetate methyltransferase and creatine kinase isoenzymes. Subcell Biochem 2008; 46:119-48. [PMID: 18652075 DOI: 10.1007/978-1-4020-6486-9_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Mice with an under- or over-expression of enzymes catalyzing phosphoryl transfer in high-energy supplying reactions are particulary attractive for in vivo magnetic resonance spectroscopy (MRS) studies as substrates of these enzymes are visible in MR spectra. This chapter reviews results of in vivo MRS studies on transgenic mice with alterations in the expression of the enzymes creatine kinase and guanidinoacetate methyltransferase. The particular metabolic consequences of these enzyme deficiencies in skeletal muscle, brain, heart and liver are addressed. An overview is given of metabolite levels determined by in vivo MRS in skeletal muscle and brain of wild-type and transgenic mice. MRS studies on mice lacking guanidinoacetate methyltransferase have demonstrated metabolic changes comparable to those found in the deficiency of this enzyme in humans, which are (partly) reversible upon creatine feeding. Apart from being a model for a creatine deficiency syndrome, these mice are also of interest to study fundamental aspects of the biological role of creatine. MRS studies on transgenic mice lacking creatine kinase isoenzymes have contributed significantly to the view that the creatine kinase reaction together with other enzymatic steps involved in high-energy phosphate transfer builds a large metabolic energy network, which is highly versatile and can dynamically adapt to genotoxic or physiological challenges.
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Affiliation(s)
- Arend Heerschap
- Department of Radiology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, the Netherlands
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97
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Creatine uptake in mouse hearts with genetically altered creatine levels. J Mol Cell Cardiol 2008; 45:453-9. [PMID: 18602925 PMCID: PMC2568826 DOI: 10.1016/j.yjmcc.2008.05.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 05/22/2008] [Accepted: 05/30/2008] [Indexed: 11/24/2022]
Abstract
Creatine plays an important role in energy metabolism in the heart. Cardiomyocytes accumulate creatine via a specific creatine transporter (CrT), the capacity of which is reduced in the failing heart, resulting in lower myocardial creatine concentration. Therefore, to gain insight into how the CrT is regulated, we studied two mouse models of severely altered myocardial creatine levels. Cardiac creatine uptake levels were measured in isolated hearts from creatine-free guanidinoacetate-N-methyl transferase knock out (GAMT−/−) mice and from mice overexpressing the myocardial CrT (CrT-OE) using 14C-radiolabeled creatine. CrT mRNA levels were measured using real time RT-PCR and creatine levels with HPLC. Hearts from GAMT−/− mice showed a 7-fold increase in Vmax of creatine uptake and a 1.4-fold increase in CrT mRNA levels. The increase in Cr uptake and in CrT mRNA levels, however, was almost completely prevented when mice were fed a creatine supplemented diet, indicating that creatine uptake is subject to negative feedback regulation. Cardiac creatine uptake levels in CrT-OE mice were increased on average 2.7-fold, showing a considerable variation, in line with a similar variation in creatine content. Total CrT mRNA levels correlated well with myocardial creatine content (r = 0.67; p < 0.0001) but endogenous CrT mRNA levels did not correlate at all with myocardial creatine content (r = 0.01; p = 0.96). This study shows that creatine uptake can be massively upregulated in the heart, by almost an order of magnitude and that this upregulation is subject to feedback inhibition. In addition, our results strongly suggest that CrT activity is predominantly regulated by mechanisms other than alterations in gene expression.
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98
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Braissant O, Cagnon L, Monnet-Tschudi F, Speer O, Wallimann T, Honegger P, Henry H. Ammonium alters creatine transport and synthesis in a 3D culture of developing brain cells, resulting in secondary cerebral creatine deficiency. Eur J Neurosci 2008; 27:1673-85. [DOI: 10.1111/j.1460-9568.2008.06126.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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99
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Braissant O, Henry H. AGAT, GAMT and SLC6A8 distribution in the central nervous system, in relation to creatine deficiency syndromes: a review. J Inherit Metab Dis 2008; 31:230-9. [PMID: 18392746 DOI: 10.1007/s10545-008-0826-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/01/2008] [Accepted: 02/05/2008] [Indexed: 11/25/2022]
Abstract
Creatine deficiency syndromes, either due to AGAT, GAMT or SLC6A8 deficiencies, lead to a complete absence, or a very strong decrease, of creatine within the brain, as measured by magnetic resonance spectroscopy. While the mammalian central nervous system (CNS) expresses AGAT, GAMT and SLC6A8, the lack of SLC6A8 in astrocytes around the blood-brain barrier limits the brain capacity to import creatine from the periphery, and suggests that the CNS has to rely mainly on endogenous creatine synthesis through AGAT and GAMT expression. This seems contradictory with SLC6A8 deficiency, which, despite AGAT and GAMT expression, also leads to creatine deficiency in the CNS. We present novel data showing that in cortical grey matter, AGAT and GAMT are expressed in a dissociated way: e.g. only a few cells co-express both genes. This suggests that to allow synthesis of creatine within the CNS, at least for a significant part of it, guanidinoacetate must be transported from AGAT- to GAMT-expressing cells, possibly through SLC6A8. This would explain the creatine deficiency observed in SLC6A8-deficient patients. By bringing together creatine deficiency syndromes, AGAT, GAMT and SLC6A8 distribution in CNS, as well as a synthetic view on creatine and guanidinoacetate levels in the brain, this review presents a comprehensive framework, including new hypotheses, on brain creatine metabolism and transport, both in normal conditions and in case of creatine deficiency.
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Affiliation(s)
- O Braissant
- Inborn Errors of Metabolism, Clinical Chemistry Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland.
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100
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Schneider JE, Stork LA, Bell JT, Hove MT, Isbrandt D, Clarke K, Watkins H, Lygate CA, Neubauer S. Cardiac structure and function during ageing in energetically compromised Guanidinoacetate N-methyltransferase (GAMT)-knockout mice - a one year longitudinal MRI study. J Cardiovasc Magn Reson 2008; 10:9. [PMID: 18275592 PMCID: PMC2254407 DOI: 10.1186/1532-429x-10-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 02/06/2008] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND High-resolution magnetic resonance imaging (cine-MRI) is well suited for determining global cardiac function longitudinally in genetically or surgically manipulated mice, but in practice it is seldom used to its full potential. In this study, male and female guanidinoacetate N-methyltransferase (GAMT) knockout, and wild type littermate mice were subjected to a longitudinal cine-MRI study at four time points over the course of one year. GAMT is an essential enzyme in creatine biosynthesis, such that GAMT deficient mice are entirely creatine-free. Since creatine plays an important role in the buffering and transfer of high-energy phosphate bonds in the heart, it was hypothesized that lack of creatine would be detrimental for resting cardiac performance during ageing. METHODS Measurements of cardiac structure (left ventricular mass and volumes) and function (ejection fraction, stroke volume, cardiac output) were obtained using high-resolution cine-MRI at 9.4 T under isoflurane anaesthesia. RESULTS There were no physiologically significant differences in cardiac function between wild type and GAMT knockout mice at any time point for male or female groups, or for both combined (for example ejection fraction: 6 weeks (KO vs. WT): 70 +/- 6% vs. 65 +/- 7%; 4 months: 70 +/- 6% vs. 62 +/- 8%; 8 months: 62 +/- 11% vs. 62 +/- 6%; 12 months: 61 +/- 7% vs. 59 +/- 11%, respectively). CONCLUSION These findings suggest the presence of comprehensive adaptations in the knockout mice that can compensate for a lack of creatine. Furthermore, this study clearly demonstrates the power of cine-MRI for accurate non-invasive, serial cardiac measurements. Cardiac growth curves could easily be defined for each group, in the same set of animals for all time points, providing improved statistical power, and substantially reducing the number of mice required to conduct such a study. This technique should be eminently useful for following changes of cardiac structure and function during ageing.
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Affiliation(s)
| | - Lee-Anne Stork
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Jordana T Bell
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Michiel ten Hove
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Dirk Isbrandt
- Centre for Molecular Neurobiology Hamburg (ZMNH), Institute for Neural Signal Transduction, Hamburg, Germany
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Craig A Lygate
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
| | - Stefan Neubauer
- Department of Cardiovascular Medicine, University of Oxford, Oxford, UK
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