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Aghamollaii V, Meshkat S, Bakhtiari S, Alehabib E, Firouzabadi SG, Molaei S, Kruer MC, Darvish H. Guanidinoacetate Methyltransferase Deficiency, a Treatable Neurodevelopmental Disorder. JOURNAL OF PEDIATRIC EPILEPSY 2023. [DOI: 10.1055/s-0042-1760291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AbstractGuanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessive inborn error of creatine synthesis that results in intellectual disability, epilepsy, expressive language delay, and dystonia. We report data from two siblings with an uncommon GAMT deficiency phenotype and their clinical, biochemical, imaging, and treatment findings. The older sibling had intellectual disability, epilepsy, and generalized dystonia. The younger sibling had intellectual disability and generalized dystonia. After treatment with creatine, verbal fluency improved, as well as dystonia and aggression. This study confirms that in patients with unexplained intellectual disability, epilepsy, and/or movement disorders, GAMT deficiency should be considered. GAMT-associated cerebral creatine deficiency syndrome is a potentially treatable condition and can be identified by elevated levels of guanidinoacetate in plasma or urine or by a significantly decreased creatine peak on magnetic resonance spectroscopy.
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Affiliation(s)
- Vajiheh Aghamollaii
- Neurology Department, Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Shakila Meshkat
- Neurology Department, Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children's Hospital, University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, United States
| | - Elham Alehabib
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Samira Molaei
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Michael C. Kruer
- Barrow Neurological Institute, Phoenix Children's Hospital, University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, United States
| | - Hossein Darvish
- Cancer Research Center, Department of Medical Genetics, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran
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Lack of Epileptogenic Effects of the Creatine Precursor Guanidinoacetic Acid on Neuronal Cultures In Vitro. Biomolecules 2022; 13:biom13010074. [PMID: 36671459 PMCID: PMC9856136 DOI: 10.3390/biom13010074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/19/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
The creatine precursor Guanidinoacetic Acid (GAA) accumulates in the genetic deficiency of the GuanidinoAcetate Methyl Transferase (GAMT) enzyme and it is believed to cause the seizures that often occur in this condition. However, evidence that it is indeed epileptogenic is scarce and we previously found that it does not cause neuronal hyperexcitation in in vitro brain slices. Here, we used Micro-Electrode Arrays (MEAs) to further investigate the electrophysiological effects of its acute and chronic administration in the networks of cultured neurons, either neocortical or hippocampal. We found that: (1) GAA at the 1 µM concentration, comparable to its concentration in normal cerebrospinal fluid, does not modify any of the parameters we investigated in either neuronal type; (2) at the 10 µM concentration, very similar to that found in the GAMT deficiency, it did not affect any of the parameters we tested except the bursting rate of neocortical networks and the burst duration of hippocampal networks, both of which were decreased, a change pointing in a direction opposite to epileptogenesis; (3) at the very high and unphysiological 100 µM concentration, it caused a decrease in all parameters, a change that again goes in the direction opposite to epileptogenesis. Our results confirm that GAA is not epileptogenic.
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Khoja S, Lambert J, Nitzahn M, Eliav A, Zhang Y, Tamboline M, Le CT, Nasser E, Li Y, Patel P, Zhuravka I, Lueptow LM, Tkachyova I, Xu S, Nissim I, Schulze A, Lipshutz GS. Gene therapy for guanidinoacetate methyltransferase deficiency restores cerebral and myocardial creatine while resolving behavioral abnormalities. Mol Ther Methods Clin Dev 2022; 25:278-296. [PMID: 35505663 PMCID: PMC9051621 DOI: 10.1016/j.omtm.2022.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/27/2022] [Indexed: 11/06/2022]
Abstract
Creatine deficiency disorders are inborn errors of creatine metabolism, an energy homeostasis molecule. One of these, guanidinoacetate N-methyltransferase (GAMT) deficiency, has clinical characteristics that include features of autism, self-mutilation, intellectual disability, and seizures, with approximately 40% having a disorder of movement; failure to thrive can also be a component. Along with low creatine levels, guanidinoacetic acid (GAA) toxicity has been implicated in the pathophysiology of the disorder. Present-day therapy with oral creatine to control GAA lacks efficacy; seizures can persist. Dietary management and pharmacological ornithine treatment are challenging. Using an AAV-based gene therapy approach to express human codon-optimized GAMT in hepatocytes, in situ hybridization, and immunostaining, we demonstrated pan-hepatic GAMT expression. Serial collection of blood demonstrated a marked early and sustained reduction of GAA with normalization of plasma creatine; urinary GAA levels also markedly declined. The terminal time point demonstrated marked improvement in cerebral and myocardial creatine levels. In conjunction with the biochemical findings, treated mice gained weight to nearly match their wild-type littermates, while behavioral studies demonstrated resolution of abnormalities; PET-CT imaging demonstrated improvement in brain metabolism. In conclusion, a gene therapy approach can result in long-term normalization of GAA with increased creatine in guanidinoacetate N-methyltransferase deficiency and at the same time resolves the behavioral phenotype in a murine model of the disorder. These findings have important implications for the development of a new therapy for this abnormality of creatine metabolism.
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Affiliation(s)
- Suhail Khoja
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - Jenna Lambert
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - Matthew Nitzahn
- Molecular Biology Institute, UCLA, Los Angeles, CA 90025, USA
| | - Adam Eliav
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - YuChen Zhang
- Semel Institute for Neuroscience, UCLA, Los Angeles, CA 90025, USA
| | - Mikayla Tamboline
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA 90025, USA.,Departments of Molecular and Medical Pharmacology, Universtiy of California, Los Angeles, CA 90025, USA
| | - Colleen T Le
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - Eram Nasser
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - Yunfeng Li
- Departments of Pathology and Laboratory Medicine, UCLA, Los Angeles, CA 90025, USA
| | - Puja Patel
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA
| | - Irina Zhuravka
- Behavioral Testing Core, Department of Psychology, UCLA, Los Angeles, CA 90025, USA
| | - Lindsay M Lueptow
- Behavioral Testing Core, Department of Psychology, UCLA, Los Angeles, CA 90025, USA
| | - Ilona Tkachyova
- Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Shili Xu
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA 90025, USA.,Departments of Molecular and Medical Pharmacology, Universtiy of California, Los Angeles, CA 90025, USA.,Jonsson Comprehensive Cancer Center at UCLA, David Geffen School of Medicine at UCLA, Los Angeles, CA 90025, USA
| | - Itzhak Nissim
- Division of Metabolism and Human Genetics, Children's Hospital of Philadelphia, and the Department of Biochemistry and Biophysics, Perlman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andreas Schulze
- Department of Paediatrics, University of Toronto, Toronto, ON M5G 1X8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON M5G 1X8, Canada.,Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Gerald S Lipshutz
- Department of Surgery, UCLA, Los Angeles, CA 90025, USA.,Molecular Biology Institute, UCLA, Los Angeles, CA 90025, USA.,Semel Institute for Neuroscience, UCLA, Los Angeles, CA 90025, USA.,Departments of Molecular and Medical Pharmacology, Universtiy of California, Los Angeles, CA 90025, USA.,Intellectual and Developmental Disabilities Research Center, UCLA, Los Angeles, CA 90025, USA
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Ostojic SM. Guanidinoacetic Acid as a Nutritional Adjuvant to Multiple Sclerosis Therapy. Front Hum Neurosci 2022; 16:871535. [PMID: 35634212 PMCID: PMC9134824 DOI: 10.3389/fnhum.2022.871535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
Tackling impaired bioenergetics in multiple sclerosis (MS) has been recently recognized as an innovative approach with therapeutic potential. Guanidinoacetic acid (GAA) is an experimental nutrient that plays a significant role in high-energy phosphate metabolism. The preliminary trials suggest beneficial effects of supplemental GAA in MS, with GAA augments biomarkers of brain energy metabolism and improves patient-reported features of the disease. GAA can also impact other metabolic footprints of MS, including demyelination, oxidative stress, and GABA-glutamate imbalance. In this mini-review article, we summarize studies evaluating GAA effectiveness in MS, explore mechanisms of GAA action, and discuss the challenges of using dietary GAA as an element of MS therapy.
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Affiliation(s)
- Sergej M. Ostojic
- Department of Nutrition and Public Health, University of Agder, Kristiansand, Norway
- Faculty of Sport and Physical Education (FSPE) Applied Bioenergetics Lab, University of Novi Sad, Novi Sad, Serbia
- Faculty of Health Sciences, University of Pécs, Pécs, Hungary
- *Correspondence: Sergej M. Ostojic,
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Fernandes-Pires G, Braissant O. Current and potential new treatment strategies for creatine deficiency syndromes. Mol Genet Metab 2022; 135:15-26. [PMID: 34972654 DOI: 10.1016/j.ymgme.2021.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 12/16/2022]
Abstract
Creatine deficiency syndromes (CDS) are inherited metabolic disorders caused by mutations in GATM, GAMT and SLC6A8 and mainly affect central nervous system (CNS). AGAT- and GAMT-deficient patients lack the functional brain endogenous creatine (Cr) synthesis pathway but express the Cr transporter SLC6A8 at blood-brain barrier (BBB), and can thus be treated by oral supplementation of high doses of Cr. For Cr transporter deficiency (SLC6A8 deficiency or CTD), current treatment strategies benefit one-third of patients. However, as their phenotype is not completely reversed, and for the other two-thirds of CTD patients, the development of novel more effective therapies is needed. This article aims to review the current knowledge on Cr metabolism and CDS clinical aspects, highlighting their current treatment possibilities and the most recent research perspectives on CDS potential therapeutics designed, in particular, to bring new options for the treatment of CTD.
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Affiliation(s)
- Gabriella Fernandes-Pires
- Service of Clinical Chemistry, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland
| | - Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
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Sinha A, Ahmed S, George C, Tsagaris M, Naufer A, von Both I, Tkachyova I, van Eede M, Henkelman M, Schulze A. Magnetic resonance imaging reveals specific anatomical changes in the brain of Agat- and Gamt-mice attributed to creatine depletion and guanidinoacetate alteration. J Inherit Metab Dis 2020; 43:827-842. [PMID: 31951021 DOI: 10.1002/jimd.12215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/30/2019] [Accepted: 01/09/2020] [Indexed: 11/07/2022]
Abstract
Arginine:glycine amidinotransferase- and guanidinoacetate methyltransferase deficiency are severe neurodevelopmental disorders. It is not known whether mouse models of disease express a neuroanatomical phenotype. High-resolution magnetic resonance imaging (MRI) with advanced image analysis was performed in perfused, fixed mouse brains encapsulated with the skull from male, 10-12 week old Agat -exc and B6J.Cg-Gamt tm1Isb mice (n = 48; n = 8 per genotype, strain). T2-weighted MRI scans were nonlinearly aligned to a 3D atlas of the mouse brain with 62 structures identified. Local differences in brain shape related to genotype were assessed by analysis of deformation fields. Creatine (Cr) and guanidinoacetate (GAA) were measured with high-performance liquid chromatography (HPLC) in brain homogenates (n = 24; n = 4 per genotype, strain) after whole-body perfusion. Cr was decreased in the brain of Agat- and Gamt mutant mice. GAA was decreased in Agat-/- and increased in Gamt-/- . Body weight and brain volume were lower in Agat-/- than in Gamt-/- . The analysis of entire brain structures revealed corpus callosum, internal capsule, fimbria and hypothalamus being different between the genotypes in both strains. Eighteen and fourteen significant peaks (local areas of difference in relative size) were found in Agat- and Gamt mutants, respectively. Comparing Agat-/- with Gamt-/- , we found changes in three brain regions, lateral septum, amygdala, and medulla. Intra-strain differences in four brain structures can be associated with Cr deficiency, while the inter-strain differences in three brain structures of the mutant mice may relate to GAA. Correlating these neuroanatomical findings with gene expression data implies the role of Cr metabolism in the developing brain and the importance of early intervention in patients with Cr deficiency syndromes.
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Affiliation(s)
- Ankit Sinha
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sohail Ahmed
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chris George
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Melina Tsagaris
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Amriya Naufer
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ingo von Both
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ilona Tkachyova
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Matthijs van Eede
- Mouse Imaging Centre, Toronto Center of Phenogenomics, Toronto, Ontario, Canada
| | - Mark Henkelman
- Mouse Imaging Centre, Toronto Center of Phenogenomics, Toronto, Ontario, Canada
- Neurosciences and Mental Health Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andreas Schulze
- Genetics and Genome Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Aksentijević D, Zervou S, Eykyn TR, McAndrew DJ, Wallis J, Schneider JE, Neubauer S, Lygate CA. Age-Dependent Decline in Cardiac Function in Guanidinoacetate- N-Methyltransferase Knockout Mice. Front Physiol 2020; 10:1535. [PMID: 32038270 PMCID: PMC6985570 DOI: 10.3389/fphys.2019.01535] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023] Open
Abstract
Aim Guanidinoacetate N-methyltransferase (GAMT) is the second essential enzyme in creatine (Cr) biosynthesis. Short-term Cr deficiency is metabolically well tolerated as GAMT–/– mice exhibit normal exercise capacity and response to ischemic heart failure. However, we hypothesized long-term consequences of Cr deficiency and/or accumulation of the Cr precursor guanidinoacetate (GA). Methods Cardiac function and metabolic profile were studied in GAMT–/– mice >1 year. Results In vivo LV catheterization revealed lower heart rate and developed pressure in aging GAMT–/– but normal lung weight and survival versus age-matched controls. Electron microscopy indicated reduced mitochondrial volume density in GAMT–/– hearts (P < 0.001), corroborated by lower mtDNA copy number (P < 0.004), and citrate synthase activity (P < 0.05), however, without impaired mitochondrial respiration. Furthermore, myocardial energy stores and key ATP homeostatic enzymes were barely altered, while pathology was unrelated to oxidative stress since superoxide production and protein carbonylation were unaffected. Gene expression of PGC-1α was 2.5-fold higher in GAMT–/– hearts while downstream genes were not activated, implicating a dysfunction in mitochondrial biogenesis signaling. This was normalized by 10 days of dietary Cr supplementation, as were all in vivo functional parameters, however, it was not possible to differentiate whether relief from Cr deficiency or GA toxicity was causative. Conclusion Long-term Cr deficiency in GAMT–/– mice reduces mitochondrial volume without affecting respiratory function, most likely due to impaired biogenesis. This is associated with hemodynamic changes without evidence of heart failure, which may represent an acceptable functional compromise in return for reduced energy demand in aging mice.
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Affiliation(s)
- Dunja Aksentijević
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Sevasti Zervou
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Thomas R Eykyn
- Department of Imaging Chemistry and Biology, School of Biomedical Engineering and Imaging Sciences, King's College London, St Thomas' Hospital, London, United Kingdom
| | - Debra J McAndrew
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Julie Wallis
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Jurgen E Schneider
- Experimental and Preclinical Imaging Centre, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Stefan Neubauer
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Craig A Lygate
- Radcliffe Department of Medicine, Division of Cardiovascular Medicine and Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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Untargeted metabolomic profiling reveals multiple pathway perturbations and new clinical biomarkers in urea cycle disorders. Genet Med 2019; 21:1977-1986. [PMID: 30670878 PMCID: PMC6650380 DOI: 10.1038/s41436-019-0442-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/09/2019] [Indexed: 12/30/2022] Open
Abstract
Purpose: Untargeted metabolomic analysis is increasingly being used in the screening and management of individuals with inborn errors of metabolism (IEM). We aimed to test whether untargeted metabolomic analysis in plasma might be useful for monitoring the disease course and management of urea cycle disorders (UCDs). Methods: Untargeted mass spectrometry-based metabolomic analysis was used to generate z-scores for more than 900 metabolites in plasma from 48 individuals with various UCDs. Pathway analysis was used to identify common pathways that were perturbed in each UCD. Results: Our metabolomic analysis in plasma identified multiple potentially neurotoxic metabolites of arginine in arginase deficiency and, thus, may have utility in monitoring the efficacy of treatment in arginase deficiency. In addition, we were also able to detect multiple biochemical perturbations in all UCDs that likely reflect clinical management, including metabolite alterations secondary to dietary and medication management. Conclusions: In addition to utility in screening for IEM, our results suggest that untargeted metabolomic analysis in plasma may be beneficial for monitoring efficacy of clinical management and off-target effects of medications in UCDs and potentially other IEM.
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Kölker S. Metabolism of amino acid neurotransmitters: the synaptic disorder underlying inherited metabolic diseases. J Inherit Metab Dis 2018; 41:1055-1063. [PMID: 29869166 DOI: 10.1007/s10545-018-0201-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/09/2018] [Accepted: 05/14/2018] [Indexed: 10/14/2022]
Abstract
Amino acids are involved in various metabolic pathways and some of them also act as neurotransmitters. Since biosynthesis of L-glutamate and γ-aminobutyric acid (GABA) requires 2-oxoglutarate while 3-phosphoglycerate is the precursor of L-glycine and D-serine, evolutionary selection of these amino acid neurotransmitters might have been driven by their capacity to provide important information about the glycolytic pathway and Krebs cycle. Synthesis and recycling of amino acid neurotransmitters as well as composition and function of their receptors are often compromised in inherited metabolic diseases. For instance, increased plasma L-phenylalanine concentrations impair cerebral biosynthesis of protein and bioamines in phenylketonuria, while elevated cerebral L-phenylalanine directly acts via ionotropic glutamate receptors. In succinic semialdehyde dehydrogenase deficiency, the neurotransmitter GABA and neuromodulatory γ-hydroxybutyric acid are elevated. Chronic hyperGABAergic state results in progressive downregulation of GABAA and GABAB receptors and impaired mitophagy. In glycine encephalopathy, the neurological phenotype is precipitated by L-glycine acting both via cortical NMDA receptors and glycine receptors in spinal cord and brain stem neurons. Serine deficiency syndromes are biochemically characterized by decreased biosynthesis of L-serine, an important neurotrophic factor, and the neurotransmitters D-serine and L-glycine. Supplementation with L-serine and L-glycine has a positive effect on seizure frequency and spasticity, while neurocognitive development can only be improved if treatment starts in utero or immediately postnatally. With novel techniques, the study of synaptic dysfunction in inherited metabolic diseases has become an emerging research field. More and better therapies are needed for these difficult-to-treat diseases.
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Affiliation(s)
- Stefan Kölker
- Division of Pediatric Neurology and Metabolic Medicine, Centre for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany.
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McKenna J, Kapfhamer D, Kinchen JM, Wasek B, Dunworth M, Murray-Stewart T, Bottiglieri T, Casero RA, Gambello MJ. Metabolomic studies identify changes in transmethylation and polyamine metabolism in a brain-specific mouse model of tuberous sclerosis complex. Hum Mol Genet 2018; 27:2113-2124. [PMID: 29635516 PMCID: PMC5985733 DOI: 10.1093/hmg/ddy118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/06/2018] [Accepted: 03/29/2018] [Indexed: 12/11/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant neurodevelopmental disorder and the quintessential disorder of mechanistic Target of Rapamycin Complex 1 (mTORC1) dysregulation. Loss of either causative gene, TSC1 or TSC2, leads to constitutive mTORC1 kinase activation and a pathologically anabolic state of macromolecular biosynthesis. Little is known about the organ-specific metabolic reprogramming that occurs in TSC-affected organs. Using a mouse model of TSC in which Tsc2 is disrupted in radial glial precursors and their neuronal and glial descendants, we performed an unbiased metabolomic analysis of hippocampi to identify Tsc2-dependent metabolic changes. Significant metabolic reprogramming was found in well-established pathways associated with mTORC1 activation, including redox homeostasis, glutamine/tricarboxylic acid cycle, pentose and nucleotide metabolism. Changes in two novel pathways were identified: transmethylation and polyamine metabolism. Changes in transmethylation included reduced methionine, cystathionine, S-adenosylmethionine (SAM-the major methyl donor), reduced SAM/S-adenosylhomocysteine ratio (cellular methylation potential), and elevated betaine, an alternative methyl donor. These changes were associated with alterations in SAM-dependent methylation pathways and expression of the enzymes methionine adenosyltransferase 2A and cystathionine beta synthase. We also found increased levels of the polyamine putrescine due to increased activity of ornithine decarboxylase, the rate-determining enzyme in polyamine synthesis. Treatment of Tsc2+/- mice with the ornithine decarboxylase inhibitor α-difluoromethylornithine, to reduce putrescine synthesis dose-dependently reduced hippocampal astrogliosis. These data establish roles for SAM-dependent methylation reactions and polyamine metabolism in TSC neuropathology. Importantly, both pathways are amenable to nutritional or pharmacologic therapy.
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Affiliation(s)
- James McKenna
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David Kapfhamer
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Brandi Wasek
- Center of Metabolomics, Baylor Scott and White Research Institute, Dallas 75204, TX, USA
| | - Matthew Dunworth
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, MD 21231, USA
| | - Tracy Murray-Stewart
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, MD 21231, USA
| | - Teodoro Bottiglieri
- Center of Metabolomics, Baylor Scott and White Research Institute, Dallas 75204, TX, USA
| | - Robert A Casero
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins School of Medicine, Baltimore, MD 21231, USA
| | - Michael J Gambello
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
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Affiliation(s)
| | - Roger Harris
- Formerly University of Chichester, Chichester, UK.
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12
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Marques EP, Wyse ATS. Guanidinoacetate Methyltransferase Deficiency. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2016. [DOI: 10.1177/2326409816669371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Eduardo P. Marques
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Angela T. S. Wyse
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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