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Andersen JV, Marian OC, Qvist FL, Westi EW, Aldana BI, Schousboe A, Don AS, Skotte NH, Wellendorph P. Deficient brain GABA metabolism leads to widespread impairments of astrocyte and oligodendrocyte function. Glia 2024; 72:1821-1839. [PMID: 38899762 DOI: 10.1002/glia.24585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/03/2024] [Accepted: 06/09/2024] [Indexed: 06/21/2024]
Abstract
The neurometabolic disorder succinic semialdehyde dehydrogenase (SSADH) deficiency leads to great neurochemical imbalances and severe neurological manifestations. The cause of the disease is loss of function of the enzyme SSADH, leading to impaired metabolism of the principal inhibitory neurotransmitter GABA. Despite the known identity of the enzymatic deficit, the underlying pathology of SSADH deficiency remains unclear. To uncover new mechanisms of the disease, we performed an untargeted integrative analysis of cerebral protein expression, functional metabolism, and lipid composition in a genetic mouse model of SSADH deficiency (ALDH5A1 knockout mice). Our proteomic analysis revealed a clear regional vulnerability, as protein alterations primarily manifested in the hippocampus and cerebral cortex of the ALDH5A1 knockout mice. These regions displayed aberrant expression of proteins linked to amino acid homeostasis, mitochondria, glial function, and myelination. Stable isotope tracing in acutely isolated brain slices demonstrated an overall maintained oxidative metabolism of glucose, but a selective decrease in astrocyte metabolic activity in the cerebral cortex of ALDH5A1 knockout mice. In contrast, an elevated capacity of oxidative glutamine metabolism was observed in the ALDH5A1 knockout brain, which may serve as a neuronal compensation of impaired astrocyte glutamine provision. In addition to reduced expression of critical oligodendrocyte proteins, a severe depletion of myelin-enriched sphingolipids was found in the brains of ALDH5A1 knockout mice, suggesting degeneration of myelin. Altogether, our study highlights that impaired astrocyte and oligodendrocyte function is intimately linked to SSADH deficiency pathology, suggesting that selective targeting of glial cells may hold therapeutic potential in this disease.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Oana C Marian
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
- School of Medical Sciences, The University of Sydney, Camperdown, New South Wales, Australia
| | - Filippa L Qvist
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anthony S Don
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
- School of Medical Sciences, The University of Sydney, Camperdown, New South Wales, Australia
| | - Niels H Skotte
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Rothman DL, Behar KL, Dienel GA. Mechanistic stoichiometric relationship between the rates of neurotransmission and neuronal glucose oxidation: Reevaluation of and alternatives to the pseudo-malate-aspartate shuttle model. J Neurochem 2024; 168:555-591. [PMID: 36089566 DOI: 10.1111/jnc.15619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 04/08/2022] [Accepted: 04/15/2022] [Indexed: 11/26/2022]
Abstract
The ~1:1 stoichiometry between the rates of neuronal glucose oxidation (CMRglc-ox-N) and glutamate (Glu)/γ-aminobutyric acid (GABA)-glutamine (Gln) neurotransmitter (NT) cycling between neurons and astrocytes (VNTcycle) has been firmly established. However, the mechanistic basis for this relationship is not fully understood, and this knowledge is critical for the interpretation of metabolic and brain imaging studies in normal and diseased brain. The pseudo-malate-aspartate shuttle (pseudo-MAS) model established the requirement for glycolytic metabolism in cultured glutamatergic neurons to produce NADH that is shuttled into mitochondria to support conversion of extracellular Gln (i.e., astrocyte-derived Gln in vivo) into vesicular neurotransmitter Glu. The evaluation of this model revealed that it could explain half of the 1:1 stoichiometry and it has limitations. Modifications of the pseudo-MAS model were, therefore, devised to address major knowledge gaps, that is, submitochondrial glutaminase location, identities of mitochondrial carriers for Gln and other model components, alternative mechanisms to transaminate α-ketoglutarate to form Glu and shuttle glutamine-derived ammonia while maintaining mass balance. All modified models had a similar 0.5 to 1.0 predicted mechanistic stoichiometry between VNTcycle and the rate of glucose oxidation. Based on studies of brain β-hydroxybutyrate oxidation, about half of CMRglc-ox-N may be linked to glutamatergic neurotransmission and localized in pre-synaptic structures that use pseudo-MAS type mechanisms for Glu-Gln cycling. In contrast, neuronal compartments that do not participate in transmitter cycling may use the MAS to sustain glucose oxidation. The evaluation of subcellular compartmentation of neuronal glucose metabolism in vivo is a critically important topic for future studies to understand glutamatergic and GABAergic neurotransmission.
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Affiliation(s)
- Douglas L Rothman
- Magnetic Resonance Research Center and Departments of Radiology and Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Kevin L Behar
- Magnetic Resonance Research Center and Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
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Tokatly Latzer I, Hanson E, Bertoldi M, García-Cazorla À, Tsuboyama M, MacMullin P, Rotenberg A, Roullet JB, Pearl PL. Autism spectrum disorder and GABA levels in children with succinic semialdehyde dehydrogenase deficiency. Dev Med Child Neurol 2023; 65:1596-1606. [PMID: 37246331 DOI: 10.1111/dmcn.15659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/30/2023] [Accepted: 05/03/2023] [Indexed: 05/30/2023]
Abstract
AIM To elucidate the etiological aspects of autism spectrum disorder (ASD) in succinic semialdehyde dehydrogenase deficiency (SSADHD), related to dysregulation of γ-aminobutyric acid (GABA) and the imbalance of excitatory and inhibitory neurotransmission. METHOD In this prospective, international study, individuals with SSADHD underwent neuropsychological assessments, as well as biochemical, neurophysiological, and neuroimaging evaluations. RESULTS Of the 29 individuals (17 females) enrolled (median age [IQR] 10 years 5 months [5 years 11 months-18 years 1 month]), 16 were diagnosed with ASD. ASD severity significantly increased with age (r = 0.67, p < 0.001) but was inversely correlated with plasma GABA (r = -0.67, p < 0.001) and γ-hydroxybutyrate levels (r = -0.538, p = 0.004), and resting motor threshold as measured by transcranial magnetic stimulation (r = -0.44, p = 0.03). A discriminative analysis indicated that an age older than 7 years 2 months (p = 0.004) and plasma GABA levels less than 2.47 μM (p = 0.01) are the threshold values beyond which the likelihood of ASD presenting in individuals with SSADHD is increased. INTERPRETATION ASD is prevalent but not universal in SSADHD, and it can be predicted by lower levels of plasma GABA and GABA-related metabolites. ASD severity in SSADHD increases with age and the loss of cortical inhibition. These findings add insight into the pathophysiology of ASD and may facilitate its early diagnosis and intervention in individuals with SSADHD.
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Affiliation(s)
- Itay Tokatly Latzer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Ellen Hanson
- Human Neurobehavioral Core Services, Division of Neurology, Boston Children's Hospital, Boston, MA, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, MA, USA
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Àngeles García-Cazorla
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Melissa Tsuboyama
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Paul MacMullin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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McNair LM, Mason GF, Chowdhury GM, Jiang L, Ma X, Rothman DL, Waagepetersen HS, Behar KL. Rates of pyruvate carboxylase, glutamate and GABA neurotransmitter cycling, and glucose oxidation in multiple brain regions of the awake rat using a combination of [2- 13C]/[1- 13C]glucose infusion and 1H-[ 13C]NMR ex vivo. J Cereb Blood Flow Metab 2022; 42:1507-1523. [PMID: 35048735 PMCID: PMC9274856 DOI: 10.1177/0271678x221074211] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Anaplerosis occurs predominately in astroglia through the action of pyruvate carboxylase (PC). The rate of PC (Vpc) has been reported for cerebral cortex (or whole brain) of awake humans and anesthetized rodents, but regional brain rates remain largely unknown and, hence, were subjected to investigation in the current study. Awake male rats were infused with either [2-13C]glucose or [1-13C]glucose (n = 27/30) for 8, 15, 30, 60 or 120 min, followed by rapid euthanasia with focused-beam microwave irradiation to the brain. Blood plasma and extracts of cerebellum, hippocampus, striatum, and cerebral cortex were analyzed by 1H-[13C]-NMR to establish 13C-enrichment time courses for glutamate-C4,C3,C2, glutamine-C4,C3, GABA-C2,C3,C4 and aspartate-C2,C3. Metabolic rates were determined by fitting a three-compartment metabolic model (glutamatergic and GABAergic neurons and astroglia) to the eighteen time courses. Vpc varied by 44% across brain regions, being lowest in the cerebellum (0.087 ± 0.004 µmol/g/min) and highest in striatum (0.125 ± 0.009) with intermediate values in cerebral cortex (0.106 ± 0.005) and hippocampus (0.114 ± 0.005). Vpc constituted 13-19% of the oxidative glucose consumption rate. Combination of cerebral cortical data with literature values revealed a positive correlation between Vpc and the rates of glutamate/glutamine-cycling and oxidative glucose consumption, respectively, consistent with earlier observations.
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Affiliation(s)
- Laura M McNair
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Graeme F Mason
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Golam Mi Chowdhury
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lihong Jiang
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Xiaoxian Ma
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kevin L Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
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Lee HHC, McGinty GE, Pearl PL, Rotenberg A. Understanding the Molecular Mechanisms of Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD): Towards the Development of SSADH-Targeted Medicine. Int J Mol Sci 2022; 23:2606. [PMID: 35269750 PMCID: PMC8910003 DOI: 10.3390/ijms23052606] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/21/2022] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare genetic disorder caused by inefficient metabolic breakdown of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Pathologic brain accumulation of GABA and γ-hydroxybutyrate (GHB), a neuroactive by-product of GABA catabolism, leads to a multitude of molecular abnormalities beginning in early life, culminating in multifaceted clinical presentations including delayed psychomotor development, intellectual disability, hypotonia, and ataxia. Paradoxically, over half of patients with SSADHD also develop epilepsy and face a significant risk of sudden unexpected death in epilepsy (SUDEP). Here, we review some of the relevant molecular mechanisms through which impaired synaptic inhibition, astrocytic malfunctions and myelin defects might contribute to the complex SSADHD phenotype. We also discuss the gaps in knowledge that need to be addressed for the implementation of successful gene and enzyme replacement SSADHD therapies. We conclude with a description of a novel SSADHD mouse model that enables 'on-demand' SSADH restoration, allowing proof-of-concept studies to fine-tune SSADH restoration in preparation for eventual human trials.
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Affiliation(s)
- Henry H. C. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Gabrielle E. McGinty
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
| | - Phillip L. Pearl
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
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Chen S, Lee J, Truong TM, Alhassen S, Baldi P, Alachkar A. Age-Related Neurometabolomic Signature of Mouse Brain. ACS Chem Neurosci 2021; 12:2887-2902. [PMID: 34283556 DOI: 10.1021/acschemneuro.1c00259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Neurometabolites are the ultimate gene products in the brain and the most precise biomolecular indicators of brain endophenotypes. Metabolomics is the only "omics" that provides a moment-to-moment "snapshot" of brain circuits' biochemical activities in response to external stimuli within the context of specific genetic variations. Although the expression levels of neurometabolites are highly dynamic, the underlying metabolic processes are tightly regulated during brain development, maturation, and aging. Therefore, this study aimed to identify mouse brain metabolic profiles in neonatal and adult stages and reconstruct both the active metabolic network and the metabolic pathway functioning. Using high-throughput metabolomics and bioinformatics analyses, we show that the neonatal mouse brain has its distinct metabolomic signature, which differs from the adult brain. Furthermore, lipid metabolites showed the most profound changes between the neonatal and adult brain, with some lipid species reaching 1000-fold changes. There were trends of age-dependent increases and decreases among lipids and non-lipid metabolites, respectively. A few lipid metabolites such as HexCers and SHexCers were almost absent in neonatal brains, whereas other non-lipid metabolites such as homoarginine were absent in the adult brains. Several molecules that act as neurotransmitters/neuromodulators showed age-dependent levels, with adenosine and GABA exhibiting around 100- and 10-fold increases in the adult compared with the neonatal brain. Of particular interest is the observation that purine and pyrimidines nucleobases exhibited opposite age-dependent changes. Bioinformatics analysis revealed an enrichment of lipid biosynthesis pathways in metabolites, whose levels increased in adult brains. In contrast, pathways involved in the metabolism of amino acids, nucleobases, glucose (glycolysis), tricarboxylic acid cycle (TCA) were enriched in metabolites whose levels were higher in the neonatal brains. Many of these pathways are associated with pathological conditions, which can be predicted as early as the neonatal stage. Our study provides an initial age-related biochemical directory of the mouse brain and warrants further studies to identify temporal brain metabolome across the lifespan, particularly during adolescence and aging. Such neurometabolomic data may provide important insight about the onset and progression of neurological/psychiatric disorders and may ultimately lead to the development of precise diagnostic biomarkers and more effective preventive/therapeutic strategies.
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Affiliation(s)
- Siwei Chen
- Department of Computer Science, School of Information and Computer Sciences, University of California—Irvine, Irvine, California 92697, United States
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California—Irvine, Irvine, California 92697, United States
| | - Justine Lee
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California—Irvine, Irvine, California 92697, United States
| | - Tri Minh Truong
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California—Irvine, Irvine, California 92697, United States
| | - Sammy Alhassen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California—Irvine, Irvine, California 92697, United States
| | - Pierre Baldi
- Department of Computer Science, School of Information and Computer Sciences, University of California—Irvine, Irvine, California 92697, United States
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California—Irvine, Irvine, California 92697, United States
| | - Amal Alachkar
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California—Irvine, Irvine, California 92697, United States
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California—Irvine, Irvine, California 92697, United States
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Alhassen S, Chen S, Alhassen L, Phan A, Khoudari M, De Silva A, Barhoosh H, Wang Z, Parrocha C, Shapiro E, Henrich C, Wang Z, Mutesa L, Baldi P, Abbott GW, Alachkar A. Intergenerational trauma transmission is associated with brain metabotranscriptome remodeling and mitochondrial dysfunction. Commun Biol 2021; 4:783. [PMID: 34168265 PMCID: PMC8225861 DOI: 10.1038/s42003-021-02255-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 05/18/2021] [Indexed: 12/21/2022] Open
Abstract
Intergenerational trauma increases lifetime susceptibility to depression and other psychiatric disorders. Whether intergenerational trauma transmission is a consequence of in-utero neurodevelopmental disruptions versus early-life mother–infant interaction is unknown. Here, we demonstrate that trauma exposure during pregnancy induces in mouse offspring social deficits and depressive-like behavior. Normal pups raised by traumatized mothers exhibited similar behavioral deficits to those induced in pups raised by their biological traumatized mothers. Good caregiving by normal mothers did not reverse prenatal trauma-induced behaviors, indicating a two-hit stress mechanism comprising both in-utero abnormalities and early-life poor parenting. The behavioral deficits were associated with profound changes in the brain metabotranscriptome. Striking increases in the mitochondrial hypoxia marker and epigenetic modifier 2-hydroxyglutaric acid in the brains of neonates and adults exposed prenatally to trauma indicated mitochondrial dysfunction and epigenetic mechanisms. Bioinformatic analyses revealed stress- and hypoxia-response metabolic pathways in the neonates, which produced long-lasting alterations in mitochondrial energy metabolism and epigenetic processes (DNA and chromatin modifications). Most strikingly, early pharmacological interventions with acetyl-L-carnitine (ALCAR) supplementation produced long-lasting protection against intergenerational trauma-induced depression. Sammy Alhassen, Siwei Chen, et al. use mouse models to examine the effects of prenatal and postnatal stress on metabolomic and transcriptomic pathways in the brain. Their results suggest that altered mitochondrial metabolism may underlie trauma-induced behavioral deficits, and that correcting metabolism with ALCAR supplementation may protect against intergenerational transmission of traumatic stress.
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Affiliation(s)
- Sammy Alhassen
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Siwei Chen
- Department of Computer Science, School of Information and Computer Sciences, University of California, Irvine, CA, USA.,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA
| | - Lamees Alhassen
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Alvin Phan
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Mohammad Khoudari
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Angele De Silva
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Huda Barhoosh
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Zitong Wang
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Chelsea Parrocha
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Emily Shapiro
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Charity Henrich
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Zicheng Wang
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA
| | - Leon Mutesa
- Center for Human Genetics, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Pierre Baldi
- Department of Computer Science, School of Information and Computer Sciences, University of California, Irvine, CA, USA.,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Amal Alachkar
- Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA. .,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, CA, USA.
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Pearl PL, Gibson KM, Roullet JB, DiBacco M. Author Response: Novel ALDH5A1 Variants and Genotype: Phenotype Correlation in SSADH Deficiency. Neurology 2021. [DOI: 10.1212/wnl.0000000000012040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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9
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Walters DC, Lawrence R, Kirby T, Ahrendsen JT, Anderson MP, Roullet JB, Murphy EJ, Gibson KM. Postmortem Analyses in a Patient With Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD): II. Histological, Lipid, and Gene Expression Outcomes in Regional Brain Tissue. J Child Neurol 2021; 36:1177-1188. [PMID: 33557678 PMCID: PMC8349921 DOI: 10.1177/0883073820987742] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This study has extended previous metabolic measures in postmortem tissues (frontal and parietal lobes, pons, cerebellum, hippocampus, and cerebral cortex) obtained from a 37-year-old male patient with succinic semialdehyde dehydrogenase deficiency (SSADHD) who expired from SUDEP (sudden unexplained death in epilepsy). Histopathologic characterization of fixed cortex and hippocampus revealed mild to moderate astrogliosis, especially in white matter. Analysis of total phospholipid mass in all sections of the patient revealed a 61% increase in cortex and 51% decrease in hippocampus as compared to (n = 2-4) approximately age-matched controls. Examination of mass and molar composition of major phospholipid classes showed decreases in phospholipids enriched in myelin, such as phosphatidylserine, sphingomyelin, and ethanolamine plasmalogen. Evaluation of gene expression (RT2 Profiler PCR Arrays, GABA, glutamate; Qiagen) revealed dysregulation in 14/15 GABAA receptor subunits in cerebellum, parietal, and frontal lobes with the most significant downregulation in ∊, θ, ρ1, and ρ2 subunits (7.7-9.9-fold). GABAB receptor subunits were largely unaffected, as were ionotropic glutamate receptors. The metabotropic glutamate receptor 6 was consistently downregulated (maximum 5.9-fold) as was the neurotransmitter transporter (GABA), member 13 (maximum 7.3-fold). For other genes, consistent dysregulation was seen for interleukin 1β (maximum downregulation 9.9-fold) and synuclein α (maximal upregulation 6.5-fold). Our data provide unique insight into SSADHD brain function, confirming astrogliosis and lipid abnormalities previously observed in the null mouse model while highlighting long-term effects on GABAergic/glutamatergic gene expression in this disorder.
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Affiliation(s)
- DC Walters
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - R Lawrence
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND
| | - T Kirby
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - JT Ahrendsen
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - MP Anderson
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - J-B Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - EJ Murphy
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND
| | - KM Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA,Correspondence: Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Health Sciences Building Room 210C, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA 99202-2131; phone 509-358-7954; fax 508-358-7667;
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10
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Novel biomarkers and age-related metabolite correlations in plasma and dried blood spots from patients with succinic semialdehyde dehydrogenase deficiency. Orphanet J Rare Dis 2020; 15:261. [PMID: 32967698 PMCID: PMC7510106 DOI: 10.1186/s13023-020-01522-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/24/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Previous work has identified age-related negative correlations for γ-hydroxybutyric acid (GHB) and γ-aminobutyric acid (GABA) in plasma of patients with succinic semialdehyde dehydrogenase deficiency (SSADHD). Using plasma and dried blood spots (DBS) collected in an ongoing natural history study, we tested the hypothesis that other biomarkers would follow a similar age-related negative correlation as seen for GHB/GABA. Samples (mixed sex) included: patients (n = 21 unique samples, 1-39.5 yrs) and parallel controls (n = 9 unique samples, 8.4-34.8 yrs). Archival control data (DBS only; n = 171, 0.5-39.9 yrs) was also included. RESULTS Metabolites assessed included amino acids (plasma, DBS) and acylcarnitines, creatine, creatinine, and guanidinoacetate (DBS only). Age-related negative correlations for glycine (plasma, DBS) and sarcosine (N-methylglycine, plasma) were detected, accompanied by elevated proline and decreased levels of succinylacetone, argininosuccinate, formaminoglutamate, and creatinine. Significantly low acylcarnitines were detected in patients across all chain lengths (short-, medium- and long-chain). Significant age-dependent positive correlations for selected acylcarnitines (C6-, C12DC(dicarboxylic)-, C16-, C16:1-, C18:1-, C18:2OH-carnitines) were detected in patients and absent in controls. Receiver operating characteristic (ROC) curves for all binary comparisons revealed argininosuccinate and succinylacetone to be the most discriminating biomarkers (area > 0.92). CONCLUSIONS Age-dependent acylcarnitine correlations may represent metabolic compensation responsive to age-related changes in GHB and GABA. Our study highlights novel biomarkers in SSADHD and expands the metabolic pathophysiology of this rare disorder of GABA metabolism.
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11
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Deng XY, Gan XX, Feng JH, Cai WS, Wang XQ, Shen L, Luo HT, Chen Z, Guo M, Cao J, Shen F, Xu B. ALDH5A1 acts as a tumour promoter and has a prognostic impact in papillary thyroid carcinoma. Cell Biochem Funct 2020; 39:317-325. [PMID: 32881051 DOI: 10.1002/cbf.3584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/12/2020] [Accepted: 08/01/2020] [Indexed: 12/13/2022]
Abstract
Thyroid cancer is the most common endocrine carcinoma, with papillary thyroid carcinoma (PTC) accounting for 80%-90% of thyroid cancers. Accumulating studies reported that mitochondria plays an important role in the regulation of cell proliferation. ALDH5A1, may function as an oncogene or tumour suppressor in various human cancers, and the role of ALDH5A1 in PTC is still unclear. The aim of this study was to investigate the clinical significance of ALDH5A1 expression and its functions in PTC. In this present study, we studied ALDH5A1 expression on primary papillary thyroid carcinoma (PTC) in The Cancer Genome Atlas (TCGA) database. Results showed that the levels of ALDH5A1 were found positively correlated with tumour stage, metastasis, lymph node stage, and higher levels of ALDH5A1 demonstrated poor disease-free survival (DFS). Immunohistochemistry (IHC) revealed that significantly higher expression of ALDH5A1 was found in PTC tissues. On the other hand, knockdown of ALDH5A1 significantly inhibited PTC cell proliferation, migration and invasion detection found the migration and invasion of cells also were hindered when ALDH5A1 level was reduced. The knockdown of ALDH5A1 inhibited the expression of Vimentin and promoted the expression of E-cadherin. In brief, knockdown of ALDH5A1may act as a novel molecular target for the prevention and treatment of PTC. SIGNIFICANCE OF THE STUDY: The present study focused on the role and the potential mechanism of ALDH5A1 in papillary thyroid carcinoma. We demonstrated that reduced expression of ALDH5A1 might inhibit the progression of TC by inhibiting cell proliferation, migration and invasion and reversing epithelial-mesenchymal transition (EMT). The findings ensured the interaction relation between ALDH5A1 and EMT in PTC, providing a novel biological marker for PTC and enriching the potential strategies for TC treatment.
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Affiliation(s)
- Xing-Yan Deng
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Xiao-Xiong Gan
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Jian-Hua Feng
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Wen-Song Cai
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Xin-Quan Wang
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China
| | - Liang Shen
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Hong-Tu Luo
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Zhen Chen
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Mengli Guo
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Jie Cao
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Fei Shen
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
| | - Bo Xu
- Department of Thyroid Surgery, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, PR China.,Department of Thyroid Surgery, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, PR China
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12
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Andersen JV, Jakobsen E, Westi EW, Lie MEK, Voss CM, Aldana BI, Schousboe A, Wellendorph P, Bak LK, Pinborg LH, Waagepetersen HS. Extensive astrocyte metabolism of γ-aminobutyric acid (GABA) sustains glutamine synthesis in the mammalian cerebral cortex. Glia 2020; 68:2601-2612. [PMID: 32584476 DOI: 10.1002/glia.23872] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022]
Abstract
Synaptic transmission is closely linked to brain energy and neurotransmitter metabolism. However, the extent of brain metabolism of the inhibitory neurotransmitter γ-aminobutyric acid (GABA), and the relative metabolic contributions of neurons and astrocytes, are yet unknown. The present study was designed to investigate the functional significance of brain GABA metabolism using isolated mouse cerebral cortical slices and slices of neurosurgically resected neocortical human tissue of the temporal lobe. By using dynamic isotope labeling, with [15 N]GABA and [U-13 C]GABA as metabolic substrates, we show that both mouse and human brain slices exhibit a large capacity for GABA metabolism. Both the nitrogen and the carbon backbone of GABA strongly support glutamine synthesis, particularly in the human cerebral cortex, indicative of active astrocytic GABA metabolism. This was further substantiated by pharmacological inhibition of the primary astrocytic GABA transporter subtype 3 (GAT3), by (S)-SNAP-5114 or 1-benzyl-5-chloro-2,3-dihydro-1H-indole-2,3-dione (compound 34), leading to significant reductions in oxidative GABA carbon metabolism. Interestingly, this was not the case when tiagabine was used to specifically inhibit GAT1, which is predominantly found on neurons. Finally, we show that acute GABA exposure does not directly stimulate glycolytic activity nor oxidative metabolism in cultured astrocytes, but can be used as an additional substrate to enhance uncoupled respiration. These results clearly show that GABA is actively metabolized in astrocytes, particularly for the synthesis of glutamine, and challenge the current view that synaptic GABA homeostasis is maintained primarily by presynaptic recycling.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria E K Lie
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline M Voss
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lars H Pinborg
- Epilepsy Clinic and Neurobiology Research Unit, Copenhagen University Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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Brown M, Turgeon C, Rinaldo P, Pop A, Salomons GS, Roullet J, Gibson KM. Longitudinal metabolomics in dried bloodspots yields profiles informing newborn screening for succinic semialdehyde dehydrogenase deficiency. JIMD Rep 2020; 53:29-38. [PMID: 32395407 PMCID: PMC7203655 DOI: 10.1002/jmd2.12075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 12/23/2022] Open
Abstract
Analyses of 19 amino acids, 38 acylcarnitines, and 3 creatine analogues (https://clir.mayo.edu) were implemented to test the hypothesis that succinic semialdehyde dehydrogenase deficiency (SSADHD) could be identified in dried bloodspots (DBS) using currently available newborn screening methodology. The study population included 17 post-newborn SSADHD DBS (age range 0.8-38 years; median, 8.2 years; 10 M; controls, 129-353 age-matched individuals, mixed gender) and 10 newborn SSADHD DBS (including first and second screens from 3 of 7 patients). Low (informative) markers in post-newborn DBS included C2- and C4-OH carnitines, ornithine, histidine and creatine, with no gender differences. For newborn DBS, informative markers included C2-, C3-, C4- and C4-OH carnitines, creatine and ornithine. Of these, only creatine demonstrated a significant change with age, revealing an approximate 4-fold decrease. We conclude that quantitation of short-chain acylcarnitines, creatine, and ornithine provides a newborn DBS profile with potential as a first tier screening tool for early detection of SSADHD. This first tier evaluation can be readily verified using a previously described second tier liquid chromatography-tandem mass spectrometry method for γ-hydroxybutyric acid in the same DBS. More extensive evaluation of this first/second tier screening approach is needed in a larger population.
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Affiliation(s)
- Madalyn Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - Coleman Turgeon
- Mayo Clinic, Department of Laboratory Medicine and PathologyRochesterMinnesota
| | - Piero Rinaldo
- Mayo Clinic, Department of Laboratory Medicine and PathologyRochesterMinnesota
| | - Ana Pop
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam University Medical CentersVrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & MetabolismAmsterdamThe Netherlands
| | - Gajja S. Salomons
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam University Medical CentersVrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & MetabolismAmsterdamThe Netherlands
- Department of Genetic Metabolic Diseases, Amsterdam University Medical CentersUniversity of Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & MetabolismAmsterdamThe Netherlands
| | - Jean‐Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
| | - K. Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical SciencesWashington State UniversitySpokaneWashington
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14
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Kirby T, Walters DC, Brown M, Jansen E, Salomons GS, Turgeon C, Rinaldo P, Arning E, Ashcraft P, Bottiglieri T, Roullet JB, Gibson KM. Post-mortem tissue analyses in a patient with succinic semialdehyde dehydrogenase deficiency (SSADHD). I. Metabolomic outcomes. Metab Brain Dis 2020; 35:601-614. [PMID: 32172518 PMCID: PMC7180121 DOI: 10.1007/s11011-020-00550-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/12/2020] [Indexed: 12/14/2022]
Abstract
Metabolomic characterization of post-mortem tissues (frontal and parietal cortices, pons, cerebellum, hippocampus, cerebral cortex, liver and kidney) derived from a 37 y.o. male patient with succinic semialdehyde dehydrogenase deficiency (SSADHD) was performed in conjunction with four parallel series of control tissues. Amino acids, acylcarnitines, guanidino- species (guanidinoacetic acid, creatine, creatinine) and GABA-related intermediates were quantified using UPLC and mass spectrometric methods that included isotopically labeled internal standards. Amino acid analyses revealed significant elevation of aspartic acid and depletion of glutamine in patient tissues. Evidence for disruption of short-chain fatty acid metabolism, manifest as altered C4OH, C5, C5:1, C5DC (dicarboxylic) and C12OH carnitines, was observed. Creatine and guanidinoacetic acids were decreased and elevated, respectively. GABA-associated metabolites (total GABA, γ-hydroxybutyric acid, succinic semialdehyde, 4-guanidinobutyrate, 4,5-dihydroxyhexanoic acid and homocarnosine) were significantly increased in patient tissues, including liver and kidney. The data support disruption of fat, creatine and amino acid metabolism as a component of the pathophysiology of SSADHD, and underscore the observation that metabolites measured in patient physiological fluids provide an unreliable reflection of brain metabolism.
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Affiliation(s)
- Trevor Kirby
- Department of Pharmacotherapy, Health Sciences Building Room 210C, College of Pharmacy and Pharmaceutical Sciences, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA, 99202-2131, USA
| | - Dana C Walters
- Department of Pharmacotherapy, Health Sciences Building Room 210C, College of Pharmacy and Pharmaceutical Sciences, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA, 99202-2131, USA
| | - Madalyn Brown
- Department of Pharmacotherapy, Health Sciences Building Room 210C, College of Pharmacy and Pharmaceutical Sciences, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA, 99202-2131, USA
| | - Erwin Jansen
- Department of Clinical Chemistry, Metabolic Unit, Amsterdam University Medical Center (Amsterdam UMC) and VU University Medical Center (VUmc), Amsterdam, the Netherlands
| | - Gajja S Salomons
- Department of Clinical Chemistry, Metabolic Unit, Amsterdam University Medical Center (Amsterdam UMC) and VU University Medical Center (VUmc), Amsterdam, the Netherlands
| | - Coleman Turgeon
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Piero Rinaldo
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Erland Arning
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Paula Ashcraft
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Teodoro Bottiglieri
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, Health Sciences Building Room 210C, College of Pharmacy and Pharmaceutical Sciences, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA, 99202-2131, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, Health Sciences Building Room 210C, College of Pharmacy and Pharmaceutical Sciences, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA, 99202-2131, USA.
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15
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Jakkamsetti V, Marin-Valencia I, Ma Q, Good LB, Terrill T, Rajasekaran K, Pichumani K, Khemtong C, Hooshyar MA, Sundarrajan C, Patel MS, Bachoo RM, Malloy CR, Pascual JM. Brain metabolism modulates neuronal excitability in a mouse model of pyruvate dehydrogenase deficiency. Sci Transl Med 2020; 11:11/480/eaan0457. [PMID: 30787166 DOI: 10.1126/scitranslmed.aan0457] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 09/25/2018] [Accepted: 01/31/2019] [Indexed: 12/25/2022]
Abstract
Glucose is the ultimate substrate for most brain activities that use carbon, including synthesis of the neurotransmitters glutamate and γ-aminobutyric acid via mitochondrial tricarboxylic acid (TCA) cycle. Brain metabolism and neuronal excitability are thus interdependent. However, the principles that govern their relationship are not always intuitive because heritable defects of brain glucose metabolism are associated with the paradoxical coexistence, in the same individual, of episodic neuronal hyperexcitation (seizures) with reduced basal cerebral electrical activity. One such prototypic disorder is pyruvate dehydrogenase (PDH) deficiency (PDHD). PDH is central to metabolism because it steers most of the glucose-derived flux into the TCA cycle. To better understand the pathophysiology of PDHD, we generated mice with brain-specific reduced PDH activity that paralleled salient human disease features, including cerebral hypotrophy, decreased amplitude electroencephalogram (EEG), and epilepsy. The mice exhibited reductions in cerebral TCA cycle flux, glutamate content, spontaneous, and electrically evoked in vivo cortical field potentials and gamma EEG oscillation amplitude. Episodic decreases in gamma oscillations preceded most epileptiform discharges, facilitating their prediction. Fast-spiking neuron excitability was decreased in brain slices, contributing to in vivo action potential burst prolongation after whisker pad stimulation. These features were partially reversed after systemic administration of acetate, which augmented cerebral TCA cycle flux, glutamate-dependent synaptic transmission, inhibition and gamma oscillations, and reduced epileptiform discharge duration. Thus, our results suggest that dysfunctional excitability in PDHD is consequent to reduced oxidative flux, which leads to decreased neuronal activation and impaired inhibition, and can be mitigated by an alternative metabolic substrate.
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Affiliation(s)
- Vikram Jakkamsetti
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Isaac Marin-Valencia
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY 10065, USA
| | - Qian Ma
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Levi B Good
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tyler Terrill
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Karthik Rajasekaran
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kumar Pichumani
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - M Ali Hooshyar
- Department of Mathematical Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Chandrasekhar Sundarrajan
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mulchand S Patel
- Department of Biochemistry, SUNY Buffalo, Buffalo, NY 14203, USA
| | - Robert M Bachoo
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Juan M Pascual
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. .,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.,Eugene McDermott Center for Human Growth & Development / Center for Human Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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16
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Brown M, Turgeon C, Rinaldo P, Roullet JB, Gibson KM. Temporal metabolomics in dried bloodspots suggests multipathway disruptions in aldh5a1 -/- mice, a model of succinic semialdehyde dehydrogenase deficiency. Mol Genet Metab 2019; 128:397-408. [PMID: 31699650 DOI: 10.1016/j.ymgme.2019.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/26/2019] [Accepted: 10/05/2019] [Indexed: 02/08/2023]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency (SSADHD; OMIM 271980) is a rare disorder featuring accumulation of neuroactive 4-aminobutyric acid (GABA; γ-aminobutyric acid, derived from glutamic acid) and 4-hydroxybutyric acid (γ-hydroxybutyric acid; GHB, a short-chain fatty acid analogue of GABA). Elevated GABA is predicted to disrupt the GABA shunt linking GABA transamination to the Krebs cycle and maintaining the balance of excitatory:inhibitory neurotransmitters. Similarly, GHB (or a metabolite) is predicted to impact β-oxidation flux. We explored these possibilities employing temporal metabolomics of dried bloodspots (DBS), quantifying amino acids, acylcarnitines, and guanidino- metabolites, derived from aldh5a1+/+, aldh5a1+/- and aldh5a1-/- mice (aldehyde dehydrogenase 5a1 = SSADH) at day of life (DOL) 20 and 42 days. At DOL 20, aldh5a1-/- mice had elevated C6 dicarboxylic (adipic acid) and C14 carnitines and threonine, combined with a significantly elevated ratio of threonine/[aspartic acid + alanine], in comparison to aldh5a1+/+ mice. Conversely, at DOL 42 aldh5a1-/- mice manifested decreased short chain carnitines (C0-C6), valine and glutamine, in comparison to aldh5a1+/+ mice. Guanidino species, including creatinine, creatine and guanidinoacetic acid, evolved from normal levels (DOL 20) to significantly decreased values at DOL 42 in aldh5a1-/- as compared to aldh5a1+/+ mice. Our results provide a novel temporal snapshot of the evolving metabolic profile of aldh5a1-/- mice while highlighting new pathomechanisms in SSADHD.
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Affiliation(s)
- Madalyn Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America
| | - Coleman Turgeon
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Piero Rinaldo
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America.
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17
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Brown MN, Walters DC, Schmidt MA, Hill J, McConnell A, Jansen EEW, Salomons GS, Arning E, Bottiglieri T, Gibson KM, Roullet JB. Maternal glutamine supplementation in murine succinic semialdehyde dehydrogenase deficiency, a disorder of γ-aminobutyric acid metabolism. J Inherit Metab Dis 2019; 42:1030-1039. [PMID: 31032972 DOI: 10.1002/jimd.12107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/29/2019] [Accepted: 04/25/2019] [Indexed: 11/09/2022]
Abstract
Murine succinic semialdehyde dehydrogenase deficiency (SSADHD) manifests with high concentrations of γ-aminobutyric acid (GABA) and γ-hydroxybutyrate (GHB) and low glutamine in the brain. To understand the pathogenic contribution of central glutamine deficiency, we exposed aldh5a1-/- (SSADHD) mice and their genetic controls (aldh5a1+/+ ) to either a 4% (w/w) glutamine-containing diet or a glutamine-free diet from conception until postnatal day 30. Endpoints included brain, liver and blood amino acids, brain GHB, ataxia scores, and open field testing. Glutamine supplementation did not improve aldh5a1-/- brain glutamine deficiency nor brain GABA and GHB. It decreased brain glutamate but did not change the ratio of excitatory (glutamate) to inhibitory (GABA) neurotransmitters. In contrast, glutamine supplementation significantly increased brain arginine (30% for aldh5a1+/+ and 18% for aldh5a1-/- mice), and leucine (12% and 18%). Glutamine deficiency was confirmed in the liver. The test diet increased hepatic glutamate in both genotypes, decreased glutamine in aldh5a1+/+ but not in aldh5a1-/- , but had no effect on GABA. Dried bloodspot analyses showed significantly elevated GABA in mutants (approximately 800% above controls) and decreased glutamate (approximately 25%), but no glutamine difference with controls. Glutamine supplementation did not impact blood GABA but significantly increased glutamine and glutamate in both genotypes indicating systemic exposure to dietary glutamine. Ataxia and pronounced hyperactivity were observed in aldh5a1-/- mice but remained unchanged by the diet intervention. The study suggests that glutamine supplementation improves peripheral but not central glutamine deficiency in experimental SSADHD. Future studies are needed to fully understand the pathogenic role of brain glutamine deficiency in SSADHD.
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Affiliation(s)
- Madalyn N Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Michelle A Schmidt
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington
| | | | | | - Erwin E W Jansen
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center & Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Gajja S Salomons
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center & Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Erland Arning
- Baylor Scott and White Research Institute, Institute of Metabolic Disease, Dallas, Texas
| | - Teodoro Bottiglieri
- Baylor Scott and White Research Institute, Institute of Metabolic Disease, Dallas, Texas
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
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18
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Oyarzabal A, Marin-Valencia I. Synaptic energy metabolism and neuronal excitability, in sickness and health. J Inherit Metab Dis 2019; 42:220-236. [PMID: 30734319 DOI: 10.1002/jimd.12071] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 01/06/2019] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
Most of the energy produced in the brain is dedicated to supporting synaptic transmission. Glucose is the main fuel, providing energy and carbon skeletons to the cells that execute and support synaptic function: neurons and astrocytes, respectively. It is unclear, however, how glucose is provided to and used by these cells under different levels of synaptic activity. It is even more unclear how diseases that impair glucose uptake and oxidation in the brain alter metabolism in neurons and astrocytes, disrupt synaptic activity, and cause neurological dysfunction, of which seizures are one of the most common clinical manifestations. Poor mechanistic understanding of diseases involving synaptic energy metabolism has prevented the expansion of therapeutic options, which, in most cases, are limited to symptomatic treatments. To shed light on the intersections between metabolism, synaptic transmission, and neuronal excitability, we briefly review current knowledge of compartmentalized metabolism in neurons and astrocytes, the biochemical pathways that fuel synaptic transmission at resting and active states, and the mechanisms by which disorders of brain glucose metabolism disrupt neuronal excitability and synaptic function and cause neurological disease in the form of epilepsy.
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Affiliation(s)
- Alfonso Oyarzabal
- Synaptic Metabolism Laboratory, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Isaac Marin-Valencia
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, New York
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19
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Vogel KR, Ainslie GR, Walters DC, McConnell A, Dhamne SC, Rotenberg A, Roullet JB, Gibson KM. Succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism: an update on pharmacological and enzyme-replacement therapeutic strategies. J Inherit Metab Dis 2018; 41:699-708. [PMID: 29460030 PMCID: PMC6041169 DOI: 10.1007/s10545-018-0153-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 12/16/2022]
Abstract
We present an update to the status of research on succinic semialdehyde dehydrogenase (SSADH) deficiency (SSADHD), a rare disorder of GABA metabolism. This is an unusual disorder featuring the accumulation of both GABA and its neuromodulatory analog, gamma-hydroxybutyric acid (GHB), and recent studies have advanced the potential clinical application of NCS-382, a putative GHB receptor antagonist. Animal studies have provided proof-of-concept that enzyme replacement therapy could represent a long-term therapeutic option. The characterization of neuronal stem cells (NSCs) derived from aldehyde dehydrogenase 5a1-/- (aldh5a1-/-) mice, the murine model of SSADHD, has highlighted NSC utility as an in vitro system in which to study therapeutics and associated toxicological properties. Gene expression analyses have revealed that transcripts encoding GABAA receptors are down-regulated and may remain largely immature in aldh5a1-/- brain, characterized by excitatory as opposed to inhibitory outputs, the latter being the expected action in the mature central nervous system. This indicates that agents altering chloride channel activity may be therapeutically relevant in SSADHD. The most recent therapeutic prospects include mTOR (mechanistic target of rapamycin) inhibitors, drugs that have received attention with the elucidation of the effects of elevated GABA on autophagy. The outlook for novel therapeutic trials in SSADHD continues to improve.
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Affiliation(s)
- Kara R Vogel
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | | | - Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | | | - Sameer C Dhamne
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA.
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Purslane protects against the reproductive toxicity of carbamazepine treatment in pilocarpine-induced epilepsy model. Asian Pac J Trop Biomed 2017. [DOI: 10.1016/j.apjtb.2017.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Vogel KR, Ainslie GR, Gibson KM. mTOR inhibitors rescue premature lethality and attenuate dysregulation of GABAergic/glutamatergic transcription in murine succinate semialdehyde dehydrogenase deficiency (SSADHD), a disorder of GABA metabolism. J Inherit Metab Dis 2016; 39:877-886. [PMID: 27518770 PMCID: PMC5114712 DOI: 10.1007/s10545-016-9959-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/15/2016] [Accepted: 06/21/2016] [Indexed: 02/07/2023]
Abstract
Recent studies have identified a role for supraphysiological gamma-aminobutyric acid (GABA) in the regulation of mechanistic target of rapamycin (mTOR), a protein kinase with pleiotropic roles in cellular development and homeostasis, including integration of growth factors and nutrient sensing and synaptic input in neurons (Lakhani et al. 2014; Vogel et al. 2015). Aldehyde dehydrogenase 5a1-deficient (aldh5a1 -/- ) mice, the murine orthologue of human succinic semialdehyde dehydrogenase deficiency (SSADHD), manifest increased GABA that disrupts mitophagy and increases mitochondria number with enhanced oxidant stress. Treatment with the mTOR inhibitor, rapamycin, significantly attenuates these GABA-related anomalies. We extend those studies through characterization of additional rapamycin analog (rapalog) agents including temsirolimus, dual mTOR inhibitors [Torin 1 and 2 (Tor 1/ Tor 2), Ku-0063794, and XL-765], as well as mTOR-independent autophagy inducers [trehalose, tat-Beclin 1, tacrolimus (FK-506), and NF-449) in aldh5a1 -/- mice. Rapamycin, Tor 1, and Tor 2 rescued these mice from premature lethality associated with status epilepticus. XL-765 extended lifespan significantly and induced weight gain in aldh5a1 -/- mice; untreated aldh5a1 -/- mice failed to increase body mass. Expression profiling of animals rescued with Tor 1/Tor 2 and XL-765 revealed multiple instances of pharmacological compensation and/or correction of GABAergic and glutamatergic receptors, GABA/glutamate transporters, and GABA/glutamate-associated proteins, with Tor 2 and XL-765 showing optimal outcomes. Our studies lay the groundwork for further evaluation of mTOR inhibitors in aldh5a1 -/- mice, with therapeutic ramifications for heritable disorders of GABA and glutamate neurotransmission.
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Affiliation(s)
- Kara R Vogel
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA.
| | - Garrett R Ainslie
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA
| | - K Michael Gibson
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA
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Parviz M, Vogel K, Gibson KM, Pearl PL. Disorders of GABA metabolism: SSADH and GABA-transaminase deficiencies. JOURNAL OF PEDIATRIC EPILEPSY 2015; 3:217-227. [PMID: 25485164 DOI: 10.3233/pep-14097] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Clinical disorders known to affect inherited gamma-amino butyric acid (GABA) metabolism are autosomal recessively inherited succinic semialdehyde dehydrogenase and GABA-transaminase deficiency. The clinical presentation of succinic semialdehyde dehydrogenase deficiency includes intellectual disability, ataxia, obsessive-compulsive disorder and epilepsy with a nonprogressive course in typical cases, although a progressive form in early childhood as well as deterioration in adulthood with worsening epilepsy are reported. GABA-transaminase deficiency is associated with a severe neonatal-infantile epileptic encephalopathy.
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Affiliation(s)
- Mahsa Parviz
- Harvard Medical School and Boston Children's Hospital, Boston, Massachusetts, USA
| | - Kara Vogel
- Biological Pharmacology, Washington State University, Pullman, Washington, USA
| | - K Michael Gibson
- Biological Pharmacology, Washington State University, Pullman, Washington, USA
| | - Phillip L Pearl
- Harvard Medical School and Boston Children's Hospital, Boston, Massachusetts, USA
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Xin L, Lanz B, Lei H, Gruetter R. Assessment of metabolic fluxes in the mouse brain in vivo using 1H-[13C] NMR spectroscopy at 14.1 Tesla. J Cereb Blood Flow Metab 2015; 35:759-65. [PMID: 25605294 PMCID: PMC4420852 DOI: 10.1038/jcbfm.2014.251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/27/2014] [Accepted: 12/15/2014] [Indexed: 01/13/2023]
Abstract
(13)C magnetic resonance spectroscopy (MRS) combined with the administration of (13)C labeled substrates uniquely allows to measure metabolic fluxes in vivo in the brain of humans and rats. The extension to mouse models may provide exclusive prospect for the investigation of models of human diseases. In the present study, the short-echo-time (TE) full-sensitivity (1)H-[(13)C] MRS sequence combined with high magnetic field (14.1 T) and infusion of [U-(13)C6] glucose was used to enhance the experimental sensitivity in vivo in the mouse brain and the (13)C turnover curves of glutamate C4, glutamine C4, glutamate+glutamine C3, aspartate C2, lactate C3, alanine C3, γ-aminobutyric acid C2, C3 and C4 were obtained. A one-compartment model was used to fit (13)C turnover curves and resulted in values of metabolic fluxes including the tricarboxylic acid (TCA) cycle flux VTCA (1.05 ± 0.04 μmol/g per minute), the exchange flux between 2-oxoglutarate and glutamate Vx (0.48 ± 0.02 μmol/g per minute), the glutamate-glutamine exchange rate V(gln) (0.20 ± 0.02 μmol/g per minute), the pyruvate dilution factor K(dil) (0.82 ± 0.01), and the ratio for the lactate conversion rate and the alanine conversion rate V(Lac)/V(Ala) (10 ± 2). This study opens the prospect of studying transgenic mouse models of brain pathologies.
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Affiliation(s)
- Lijing Xin
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Unit for Research in Schizophrenia, Department of Psychiatry, Center for Psychiatric Neuroscience, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Bernard Lanz
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hongxia Lei
- Department of Radiology, University of Geneva, Geneva, Switzerland
- Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rolf Gruetter
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Department of Radiology, University of Geneva, Geneva, Switzerland
- Department of Radiology, University of Lausanne, Lausanne, Switzerland
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Marin-Valencia I, Hooshyar MA, Pichumani K, Sherry AD, Malloy CR. The ratio of acetate-to-glucose oxidation in astrocytes from a single 13C NMR spectrum of cerebral cortex. J Neurochem 2014; 132:99-109. [PMID: 25231025 DOI: 10.1111/jnc.12948] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/13/2014] [Accepted: 09/15/2014] [Indexed: 11/30/2022]
Abstract
The (13) C-labeling patterns in glutamate and glutamine from brain tissue are quite different after infusion of a mixture of (13) C-enriched glucose and acetate. Two processes contribute to this observation, oxidation of acetate by astrocytes but not neurons, and preferential incorporation of α-ketoglutarate into glutamate in neurons, and incorporation of α-ketoglutarate into glutamine in astrocytes. The acetate:glucose ratio, introduced previously for analysis of a single (13) C NMR spectrum, provides a useful index of acetate and glucose oxidation in the brain tissue. However, quantitation of relative substrate oxidation at the cell compartment level has not been reported. A simple mathematical method is presented to quantify the ratio of acetate-to-glucose oxidation in astrocytes, based on the standard assumption that neurons do not oxidize acetate. Mice were infused with [1,2-(13) C]acetate and [1,6-(13) C]glucose, and proton decoupled (13) C NMR spectra of cortex extracts were acquired. A fit of those spectra to the model indicated that (13) C-labeled acetate and glucose contributed approximately equally to acetyl-CoA (0.96) in astrocytes. As this method relies on a single (13) C NMR spectrum, it can be readily applied to multiple physiologic and pathologic conditions. Differences in (13) C labeling of brain glutamate and glutamine have been attributed to metabolic compartmentation. The acetate:glucose ratio, introduced for description of a (13) C NMR (nuclear magnetic resonance) spectrum, is an index of glucose and acetate oxidation in brain tissue. A simple mathematical method is presented to quantify the ratio of acetate-to-glucose oxidation in astrocytes from a single NMR spectrum. As kinetic analysis is not required, the method is readily applicable to analysis of tissue extracts. α-KG = alpha-ketoglutarate; CAC = citric acid cycle; GLN = glutamine; GLU = glutamate.
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Affiliation(s)
- Isaac Marin-Valencia
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA; Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
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25
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Chowdhury GMI, Jiang L, Rothman DL, Behar KL. The contribution of ketone bodies to basal and activity-dependent neuronal oxidation in vivo. J Cereb Blood Flow Metab 2014; 34:1233-42. [PMID: 24780902 PMCID: PMC4083391 DOI: 10.1038/jcbfm.2014.77] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 03/12/2014] [Accepted: 04/06/2014] [Indexed: 01/30/2023]
Abstract
The capacity of ketone bodies to replace glucose in support of neuronal function is unresolved. Here, we determined the contributions of glucose and ketone bodies to neocortical oxidative metabolism over a large range of brain activity in rats fasted 36 hours and infused intravenously with [2,4-(13)C₂]-D-β-hydroxybutyrate (BHB). Three animal groups and conditions were studied: awake ex vivo, pentobarbital-induced isoelectricity ex vivo, and halothane-anesthetized in vivo, the latter data reanalyzed from a recent study. Rates of neuronal acetyl-CoA oxidation from ketone bodies (V(acCoA-kbN)) and pyruvate (V(pdhN)), and the glutamate-glutamine cycle (V(cyc)) were determined by metabolic modeling of (13)C label trapped in major brain amino acid pools. V(acCoA-kbN) increased gradually with increasing activity, as compared with the steeper change in tricarboxylic acid (TCA) cycle rate (V(tcaN)), supporting a decreasing percentage of neuronal ketone oxidation: ∼100% (isoelectricity), 56% (halothane anesthesia), 36% (awake) with the BHB plasma levels achieved in our experiments (6 to 13 mM). In awake animals ketone oxidation reached saturation for blood levels >17 mM, accounting for 62% of neuronal substrate oxidation, the remainder (38%) provided by glucose. We conclude that ketone bodies present at sufficient concentration to saturate metabolism provides full support of basal (housekeeping) energy needs and up to approximately half of the activity-dependent oxidative needs of neurons.
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Affiliation(s)
- Golam M I Chowdhury
- Department of Psychiatry, The Anlyan Center, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Lihong Jiang
- Department of Diagnostic Radiology, The Anlyan Center, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Diagnostic Radiology, The Anlyan Center, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kevin L Behar
- Department of Psychiatry, The Anlyan Center, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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Lanz B, Xin L, Millet P, Gruetter R. In vivo quantification of neuro-glial metabolism and glial glutamate concentration using 1H-[13C] MRS at 14.1T. J Neurochem 2013; 128:125-39. [PMID: 24117599 DOI: 10.1111/jnc.12479] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 08/31/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022]
Abstract
Astrocytes have recently become a major center of interest in neurochemistry with the discoveries on their major role in brain energy metabolism. An interesting way to probe this glial contribution is given by in vivo (13) C NMR spectroscopy coupled with the infusion labeled glial-specific substrate, such as acetate. In this study, we infused alpha-chloralose anesthetized rats with [2-(13) C]acetate and followed the dynamics of the fractional enrichment (FE) in the positions C4 and C3 of glutamate and glutamine with high sensitivity, using (1) H-[(13) C] magnetic resonance spectroscopy (MRS) at 14.1T. Applying a two-compartment mathematical model to the measured time courses yielded a glial tricarboxylic acid (TCA) cycle rate (Vg ) of 0.27 ± 0.02 μmol/g/min and a glutamatergic neurotransmission rate (VNT ) of 0.15 ± 0.01 μmol/g/min. Glial oxidative ATP metabolism thus accounts for 38% of total oxidative metabolism measured by NMR. Pyruvate carboxylase (VPC ) was 0.09 ± 0.01 μmol/g/min, corresponding to 37% of the glial glutamine synthesis rate. The glial and neuronal transmitochondrial fluxes (Vx (g) and Vx (n) ) were of the same order of magnitude as the respective TCA cycle fluxes. In addition, we estimated a glial glutamate pool size of 0.6 ± 0.1 μmol/g. The effect of spectral data quality on the fluxes estimates was analyzed by Monte Carlo simulations. In this (13) C-acetate labeling study, we propose a refined two-compartment analysis of brain energy metabolism based on (13) C turnover curves of acetate, glutamate and glutamine measured with state of the art in vivo dynamic MRS at high magnetic field in rats, enabling a deeper understanding of the specific role of glial cells in brain oxidative metabolism. In addition, the robustness of the metabolic fluxes determination relative to MRS data quality was carefully studied.
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Affiliation(s)
- Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Hertz L. The Glutamate-Glutamine (GABA) Cycle: Importance of Late Postnatal Development and Potential Reciprocal Interactions between Biosynthesis and Degradation. Front Endocrinol (Lausanne) 2013; 4:59. [PMID: 23750153 PMCID: PMC3664331 DOI: 10.3389/fendo.2013.00059] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/02/2013] [Indexed: 01/28/2023] Open
Abstract
The gold standard for studies of glutamate-glutamine (GABA) cycling and its connections to brain biosynthesis from glucose of glutamate and GABA and their subsequent metabolism are the elegant in vivo studies by (13)C magnetic resonance spectroscopy (NMR), showing the large fluxes in the cycle. However, simpler experiments in intact brain tissue (e.g., immunohistochemistry), brain slices, cultured brain cells, and mitochondria have also made important contributions to the understanding of details, mechanisms, and functional consequences of glutamate/GABA biosynthesis and degradation. The purpose of this review is to attempt to integrate evidence from different sources regarding (i) the enzyme(s) responsible for the initial conversion of α-ketoglutarate to glutamate; (ii) the possibility that especially glutamate oxidation is essentially confined to astrocytes; and (iii) the ontogenetically very late onset and maturation of glutamine-glutamate (GABA) cycle function. Pathway models based on the functional importance of aspartate for glutamate synthesis suggest the possibility of interacting pathways for biosynthesis and degradation of glutamate and GABA and the use of transamination as the default mechanism for initiation of glutamate oxidation. The late development and maturation are related to the late cortical gliogenesis and convert brain cortical function from being purely neuronal to becoming neuronal-astrocytic. This conversion is associated with huge increases in energy demand and production, and the character of potentially incurred gains of function are discussed. These may include alterations in learning mechanisms, in mice indicated by lack of pairing of odor learning with aversive stimuli in newborn animals but the development of such an association 10-12 days later. The possibility is suggested that analogous maturational changes may contribute to differences in the way learning is accomplished in the newborn human brain and during later development.
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Affiliation(s)
- Leif Hertz
- Clinical Pharmacology, Medical University of ChinaShenyang, China
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Volkow ND, Kim SW, Wang GJ, Alexoff D, Logan J, Muench L, Shea C, Telang F, Fowler JS, Wong C, Benveniste H, Tomasi D. Acute alcohol intoxication decreases glucose metabolism but increases acetate uptake in the human brain. Neuroimage 2013; 64:277-83. [PMID: 22947541 PMCID: PMC3508320 DOI: 10.1016/j.neuroimage.2012.08.057] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/09/2012] [Accepted: 08/21/2012] [Indexed: 10/28/2022] Open
Abstract
Alcohol intoxication results in marked reductions in brain glucose metabolism, which we hypothesized reflect not just its GABAergic enhancing effects but also the metabolism of acetate as an alternative brain energy source. To test this hypothesis we separately assessed the effects of alcohol intoxication on brain glucose and acetate metabolism using Positron Emission Tomography (PET). We found that alcohol intoxication significantly decreased whole brain glucose metabolism (measured with FDG) with the largest decrements in cerebellum and occipital cortex and the smallest in the thalamus. In contrast, alcohol intoxication caused a significant increase in [1-(11)C]acetate brain uptake (measured as standard uptake value, SUV), with the largest increases occurring in the cerebellum and the smallest in the thalamus. In heavy alcohol drinkers [1-(11)C]acetate brain uptake during alcohol challenge tended to be higher than in occasional drinkers (p<0.06) and the increases in [1-(11)C]acetate uptake in cerebellum with alcohol were positively associated with the reported amount of alcohol consumed (r=0.66, p<0.01). Our findings corroborate a reduction of brain glucose metabolism during intoxication and document an increase in brain acetate uptake. The opposite changes observed between regional brain metabolic decrements and regional increases in [1-(11)C]acetate uptake support the hypothesis that during alcohol intoxication the brain may rely on acetate as an alternative brain energy source and provides preliminary evidence that heavy alcohol exposures may facilitate the use of acetate as an energy substrate. These findings raise the question of the potential therapeutic benefits that increasing plasma acetate concentration (i.e. ketogenic diets) may have in alcoholics undergoing alcohol detoxification.
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Affiliation(s)
- Nora D Volkow
- National Institute on Drug Abuse, Bethesda, MD 20892, USA.
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Chowdhury GMI, Behar KL, Cho W, Thomas MA, Rothman DL, Sanacora G. ¹H-[¹³C]-nuclear magnetic resonance spectroscopy measures of ketamine's effect on amino acid neurotransmitter metabolism. Biol Psychiatry 2012; 71:1022-5. [PMID: 22169441 PMCID: PMC3660962 DOI: 10.1016/j.biopsych.2011.11.006] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 12/29/2022]
Abstract
Ketamine has recently gained significant attention owing to its psychotomimetic and more recently discovered rapid antidepressant-like properties. ¹H-[¹³C]-nuclear magnetic resonance studies were employed to explore potential physiological processes underlying these unique effects. [1-¹³C]glucose and [2-¹³C]acetate-nuclear magnetic resonance ex vivo studies were performed on the medial prefrontal cortex (mPFC) and hippocampus of rats acutely treated with 30 mg/kg or 80 mg/kg ketamine and compared with saline-treated animals to determine the effects of ketamine on amino acid neurotransmitter cycling and glial metabolism. A subanesthetic, but not anesthetic, dose of ketamine significantly increased the percentage of ¹³C-enrichments of glutamate, γ-aminobutyric acid, and glutamine in the mPFC of rats. Subanesthetic doses of ketamine increased mPFC amino acid neurotransmitter cycling, as well as neuronal and glial energy metabolism. These data add to previous reports suggesting increased mPFC levels of glutamate release, following the administration of subanesthetic doses of ketamine, are related to the drug's acute effects on cognition, perception, and mood.
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Affiliation(s)
- Golam M I Chowdhury
- Department of Psychiatry and the Ribicoff Research Facilities, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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30
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Noor NA, Aboul Ezz HS, Faraag AR, Khadrawy YA. Evaluation of the antiepileptic effect of curcumin and Nigella sativa oil in the pilocarpine model of epilepsy in comparison with valproate. Epilepsy Behav 2012; 24:199-206. [PMID: 22575751 DOI: 10.1016/j.yebeh.2012.03.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/21/2012] [Accepted: 03/23/2012] [Indexed: 10/28/2022]
Abstract
The present study aimed to investigate the effect of curcumin and Nigella sativa oil (NSO) on amino acid neurotransmitter alterations and the histological changes induced by pilocarpine in the hippocampus and cortex of rats. Epilepsy was induced by i.p. injection of pilocarpine, and the animals were left for 22 days to establish spontaneous recurrent seizures. They were then treated with curcumin, NSO or valproate for 21 days. Pilocarpine induced a significant increase in hippocampal aspartate and a significant decrease in glycine and taurine levels. In the cortex, a significant increase in aspartate, glutamate, GABA, glycine, and taurine levels was obtained after pilocarpine injection. Treatment of pilocarpinized rats with curcumin and valproate ameliorated most of the changes in amino acid concentrations and reduced the histopathological abnormalities induced by pilocarpine. N. sativa oil failed to improve the pilocarpine-induced abnormalities. This may explain the antiepileptic effect of curcumin and suggest its use as an anticonvulsant.
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Affiliation(s)
- Neveen A Noor
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt.
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31
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Rowley NM, Madsen KK, Schousboe A, Steve White H. Glutamate and GABA synthesis, release, transport and metabolism as targets for seizure control. Neurochem Int 2012; 61:546-58. [PMID: 22365921 DOI: 10.1016/j.neuint.2012.02.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 02/09/2012] [Indexed: 11/17/2022]
Abstract
The synthesis, release, reuptake, and metabolism of the excitatory and inhibitory neurotransmitters glutamate and GABA, respectively, are tightly controlled. Given the role that these two neurotransmitters play in normal and abnormal neurotransmission, it is important to consider the processes whereby they are regulated. This brief review is focused entirely on the metabolic aspects of glutamate and GABA synthesis and neurotransmission. It describes in limited detail the synthesis, release, reuptake, metabolism, cellular compartmentation and pharmacology of the glutamatergic and GABAergic synapse. This review also provides a summary and brief description of the pathologic and phenotypic features of the various genetic animal models that have been developed in an effort to provide a greater understanding of the role that each of the aforementioned metabolic processes plays in controlling excitatory and inhibitory neurotransmission and how their use will hopefully facilitate the development of safer and more efficacious therapies for the treatment of epilepsy and other neurological disorders.
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Affiliation(s)
- Nicole M Rowley
- Department of Pharmacology and Toxicology, Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, USA
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Abstract
Ketone bodies are important alternate brain fuels, but their capacity to replace glucose and support neural function is unclear. In this study, the contributions of ketone bodies and glucose to cerebral cortical metabolism were measured in vivo in halothane-anesthetized rats fasted for 36 hours (n=6) and receiving intravenous [2,4-(13)C(2)]-D-β-hydroxybutyrate (BHB). Time courses of (13)C-enriched brain amino acids (glutamate-C4, glutamine-C4, and glutamate and glutamine-C3) were measured at 9.4 Tesla using spatially localized (1)H-[(13)C]-nuclear magnetic resonance spectroscopy. Metabolic rates were estimated by fitting a constrained, two-compartment (neuron-astrocyte) metabolic model to the (13)C time-course data. We found that ketone body oxidation was substantial, accounting for 40% of total substrate oxidation (glucose plus ketone bodies) by neurons and astrocytes. D-β-Hydroxybutyrate was oxidized to a greater extent in neurons than in astrocytes (≈ 70:30), and followed a pattern closely similar to the metabolism of [1-(13)C]glucose reported in previous studies. Total neuronal tricarboxylic acid cycle (TCA) flux in hyperketonemic rats was similar to values reported for normal (nonketotic) anesthetized rats infused with [1-(13)C]glucose, but neuronal glucose oxidation was 40% to 50% lower, indicating that ketone bodies had compensated for the reduction in glucose use.
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Kim KJ, Pearl PL, Jensen K, Snead OC, Malaspina P, Jakobs C, Gibson KM. Succinic semialdehyde dehydrogenase: biochemical-molecular-clinical disease mechanisms, redox regulation, and functional significance. Antioxid Redox Signal 2011; 15:691-718. [PMID: 20973619 PMCID: PMC3125545 DOI: 10.1089/ars.2010.3470] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5a1, ALDH5A1; E.C. 1.2.1.24; OMIM 610045, 271980) deficiency is a rare heritable disorder that disrupts the metabolism of the inhibitory neurotransmitter 4-aminobutyric acid (GABA). Identified in conjunction with increased urinary excretion of the GABA analog gamma-hydroxybutyric acid (GHB), numerous patients have been identified worldwide and the autosomal-recessive disorder has been modeled in mice. The phenotype is one of nonprogressive neurological dysfunction in which seizures may be prominently displayed. The murine model is a reasonable phenocopy of the human disorder, yet the severity of the seizure disorder in the mouse exceeds that observed in SSADH-deficient patients. Abnormalities in GABAergic and GHBergic neurotransmission, documented in patients and mice, form a component of disease pathophysiology, although numerous other disturbances (metabolite accumulations, myelin abnormalities, oxidant stress, neurosteroid depletion, altered bioenergetics, etc.) are also likely to be involved in developing the disease phenotype. Most recently, the demonstration of a redox control system in the SSADH protein active site has provided new insights into the regulation of SSADH by the cellular oxidation/reduction potential. The current review summarizes some 30 years of research on this protein and disease, addressing pathological mechanisms in human and mouse at the protein, metabolic, molecular, and whole-animal level.
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Affiliation(s)
- Kyung-Jin Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Phillip L. Pearl
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
- Center for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
| | - O. Carter Snead
- Department of Neurology, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | | | - Cornelis Jakobs
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - K. Michael Gibson
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan
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Neurochemical and electrophysiological changes induced by paradoxical sleep deprivation in rats. Behav Brain Res 2011; 225:39-46. [PMID: 21729722 DOI: 10.1016/j.bbr.2011.06.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Revised: 06/12/2011] [Accepted: 06/18/2011] [Indexed: 12/26/2022]
Abstract
The present study aims to investigate the effects of paradoxical sleep deprivation (PSD) on the waking EEG and amino acid neurotransmitters in the hippocampus and cortex of rats. Animals were deprived of paradoxical sleep for 72h by using the multiple platform method. The EEG power spectral analysis was carried out to assess the brain's electrophysiological changes due to sleep deprivation. The concentrations of amino acid neurotransmitters were assessed in the hippocampus and cortex using HPLC. Control data showed slight differences from normal animals in the delta, theta and alpha waves while an increase in the beta wave was obtained. After 24h of PSD, delta relative power increased and the rest of EEG wave's power decreased with respect to control. After 48h and 72h the spectral power analysis showed non-significant changes to control. The amino acid neurotransmitter analysis revealed a significant increase in cortical glutamate, glycine and taurine levels while in the hippocampus, glutamate, aspartate, glutamine and glycine levels increased significantly. Both the waking EEG and neurotransmitter analyses suggest that PSD induced neurochemical and electrophysiological changes that may affect brain proper functionality.
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Knockout of GAD65 has major impact on synaptic GABA synthesized from astrocyte-derived glutamine. J Cereb Blood Flow Metab 2011; 31:494-503. [PMID: 20664610 PMCID: PMC3049505 DOI: 10.1038/jcbfm.2010.115] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
γ-Aminobutyric acid (GABA) synthesis from glutamate is catalyzed by glutamate decarboxylase (GAD) of which two isoforms, GAD65 and GAD67, have been identified. The GAD65 has repeatedly been shown to be important during intensified synaptic activity. To specifically elucidate the significance of GAD65 for maintenance of the highly compartmentalized intracellular and intercellular GABA homeostasis, GAD65 knockout and corresponding wild-type mice were injected with [1-(13)C]glucose and the astrocyte-specific substrate [1,2-(13)C]acetate. Synthesis of GABA from glutamine in the GABAergic synapses was further investigated in GAD65 knockout and wild-type mice using [1,2-(13)C]acetate and in some cases γ-vinylGABA (GVG, Vigabatrin), an inhibitor of GABA degradation. A detailed metabolic mapping was obtained by nuclear magnetic resonance (NMR) spectroscopic analysis of tissue extracts of cerebral cortex and hippocampus. The GABA content in both brain regions was reduced by ∼20%. Moreover, it was revealed that GAD65 is crucial for maintenance of biosynthesis of synaptic GABA particularly by direct synthesis from astrocytic glutamine via glutamate. The GAD67 was found to be important for synthesis of GABA from glutamine both via direct synthesis and via a pathway involving mitochondrial metabolism. Furthermore, a severe neuronal hypometabolism, involving glycolysis and tricarboxylic acid (TCA) cycle activity, was observed in cerebral cortex of GAD65 knockout mice.
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Walls AB, Nilsen LH, Eyjolfsson EM, Vestergaard HT, Hansen SL, Schousboe A, Sonnewald U, Waagepetersen HS. GAD65 is essential for synthesis of GABA destined for tonic inhibition regulating epileptiform activity. J Neurochem 2010; 115:1398-408. [PMID: 21039523 DOI: 10.1111/j.1471-4159.2010.07043.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
GABA is synthesized from glutamate by glutamate decarboxylase (GAD), which exists in two isoforms, that is, GAD65 and GAD67. In line with GAD65 being located in the GABAergic synapse, several studies have demonstrated that this isoform is important during sustained synaptic transmission. In contrast, the functional significance of GAD65 in the maintenance of GABA destined for extrasynaptic tonic inhibition is less well studied. Using GAD65-/- and wild type GAD65+/+ mice, this was examined employing the cortical wedge preparation, a model suitable for investigating extrasynaptic GABA(A) receptor activity. An impaired tonic inhibition in GAD65-/- mice was revealed demonstrating a significant role of GAD65 in the synthesis of GABA acting extrasynaptically. The correlation between an altered tonic inhibition and metabolic events as well as the functional and metabolic role of GABA synthesized by GAD65 was further investigated in vivo. Tonic inhibition and the demand for biosynthesis of GABA were augmented by injection of kainate into GAD65-/- and GAD65+/+ mice. Moreover, [1-(13) C]glucose and [1,2-(13) C]acetate were administered to study neuronal and astrocytic metabolism concomitantly. Subsequently, cortical and hippocampal extracts were analyzed by NMR spectroscopy and mass spectrometry, respectively. Although seizure activity was induced by kainate, neuronal hypometabolism was observed in GAD65+/+ mice. In contrast, kainate evoked hypermetabolism in GAD65-/- mice exhibiting deficiencies in tonic inhibition. These findings underline the importance of GAD65 for synthesis of GABA destined for extrasynaptic tonic inhibition, regulating epileptiform activity.
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Affiliation(s)
- Anne B Walls
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Norway
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Patel AB, de Graaf RA, Rothman DL, Behar KL, Mason GF. Evaluation of cerebral acetate transport and metabolic rates in the rat brain in vivo using 1H-[13C]-NMR. J Cereb Blood Flow Metab 2010; 30:1200-13. [PMID: 20125180 PMCID: PMC2879471 DOI: 10.1038/jcbfm.2010.2] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acetate is a well-known astrocyte-specific substrate that has been used extensively to probe astrocytic function in vitro and in vivo. Analysis of amino acid turnover curves from (13)C-acetate has been limited mainly for estimation of first-order rate constants from exponential fitting or calculation of relative rates from steady-state (13)C enrichments. In this study, we used (1)H-[(13)C]-Nuclear Magnetic Resonance spectroscopy with intravenous infusion of [2-(13)C]acetate-Na(+) in vivo to measure the cerebral kinetics of acetate transport and utilization in anesthetized rats. Kinetics were assessed using a two-compartment (neuron/astrocyte) analysis of the (13)C turnover curves of glutamate-C4 and glutamine-C4 from [2-(13)C]acetate-Na(+), brain acetate levels, and the dependence of steady-state glutamine-C4 enrichment on blood acetate levels. The steady-state enrichment of glutamine-C4 increased with blood acetate concentration until 90% of plateau for plasma acetate of 4 to 5 mmol/L. Analysis assuming reversible, symmetric Michaelis-Menten kinetics for transport yielded 27+/-2 mmol/L and 1.3+/-0.3 micromol/g/min for K(t) and T(max), respectively, and for utilization, 0.17+/-0.24 mmol/L and 0.14+/-0.02 micromol/g/min for K(M_util) and V(max_util), respectively. The distribution space for acetate was only 0.32+/-0.12 mL/g, indicative of a large excluded volume. The astrocytic and neuronal tricarboxylic acid cycle fluxes were 0.37+/-0.03 micromol/g/min and 1.41+/-0.11 micromol/g/min, respectively; astrocytes thus comprised approximately 21%+/-3% of total oxidative metabolism.
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Affiliation(s)
- Anant B Patel
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.
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Banasr M, Chowdhury GMI, Terwilliger R, Newton SS, Duman RS, Behar KL, Sanacora G. Glial pathology in an animal model of depression: reversal of stress-induced cellular, metabolic and behavioral deficits by the glutamate-modulating drug riluzole. Mol Psychiatry 2010; 15:501-11. [PMID: 18825147 PMCID: PMC3347761 DOI: 10.1038/mp.2008.106] [Citation(s) in RCA: 344] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Growing evidence indicates that glia pathology and amino-acid neurotransmitter system abnormalities contribute to the pathophysiology and possibly the pathogenesis of major depressive disorder. This study investigates changes in glial function occurring in the rat prefrontal cortex (PFC) after chronic unpredictable stress (CUS), a rodent model of depression. Furthermore, we analyzed the effects of riluzole, a Food and Drug Administration-approved drug for the treatment of amyotrophic laterosclerosis, known to modulate glutamate release and facilate glutamate uptake, on CUS-induced glial dysfunction and depressive-like behaviors. We provide the first experimental evidence that chronic stress impairs cortical glial function. Animals exposed to CUS and showing behavioral deficits in sucrose preference and active avoidance exhibited significant decreases in 13C-acetate metabolism reflecting glial cell metabolism, and glial fibrillary associated protein (GFAP) mRNA expression in the PFC. The cellular, metabolic and behavioral alterations induced by CUS were reversed and/or blocked by chronic treatment with the glutamate-modulating drug riluzole. The beneficial effects of riluzole on CUS-induced anhedonia and helplessness demonstrate the antidepressant action of riluzole in rodents. Riluzole treatment also reversed CUS-induced reductions in glial metabolism and GFAP mRNA expression. Our results are consistent with recent open-label clinical trials showing the drug's effect in mood and anxiety disorders. This study provides further validation of hypothesis that glial dysfunction and disrupted amino-acid neurotransmission contribute to the pathophysiology of depression and that modulation of glutamate metabolism, uptake and/or release represent viable targets for antidepressant drug development.
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Affiliation(s)
- M Banasr
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Ribicoff Research Facilities, Yale University School of Medicine, New Haven, CT, USA
| | - GMI Chowdhury
- Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, USA,Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - R Terwilliger
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Ribicoff Research Facilities, Yale University School of Medicine, New Haven, CT, USA
| | - SS Newton
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Ribicoff Research Facilities, Yale University School of Medicine, New Haven, CT, USA
| | - RS Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Ribicoff Research Facilities, Yale University School of Medicine, New Haven, CT, USA
| | - KL Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, USA
| | - G Sanacora
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Ribicoff Research Facilities, Yale University School of Medicine, New Haven, CT, USA
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Pearl PL, Gibson KM, Cortez MA, Wu Y, Carter Snead O, Knerr I, Forester K, Pettiford JM, Jakobs C, Theodore WH. Succinic semialdehyde dehydrogenase deficiency: lessons from mice and men. J Inherit Metab Dis 2009; 32:343-52. [PMID: 19172412 PMCID: PMC2693236 DOI: 10.1007/s10545-009-1034-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 11/14/2008] [Accepted: 11/26/2008] [Indexed: 12/23/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency, a disorder of GABA degradation with subsequent elevations in brain GABA and GHB, is a neurometabolic disorder with intellectual disability, epilepsy, hypotonia, ataxia, sleep disorders, and psychiatric disturbances. Neuroimaging reveals increased T2-weighted MRI signal usually affecting the globus pallidus, cerebellar dentate nucleus, and subthalamic nucleus, and often cerebral and cerebellar atrophy. EEG abnormalities are usually generalized spike-wave, consistent with a predilection for generalized epilepsy. The murine phenotype is characterized by failure-to-thrive, progressive ataxia, and a transition from generalized absence to tonic-clonic to ultimately fatal convulsive status epilepticus. Binding and electrophysiological studies demonstrate use-dependent downregulation of GABA(A) and (B) receptors in the mutant mouse. Translational human studies similarly reveal downregulation of GABAergic activity in patients, utilizing flumazenil-PET and transcranial magnetic stimulation for GABA(A) and (B) activity, respectively. Sleep studies reveal decreased stage REM with prolonged REM latencies and diminished percentage of stage REM. An ad libitum ketogenic diet was reported as effective in the mouse model, with unclear applicability to the human condition. Acute application of SGS-742, a GABA(B) antagonist, leads to improvement in epileptiform activity on electrocorticography. Promising mouse data using compounds available for clinical use, including taurine and SGS-742, form the framework for human trials.
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MESH Headings
- Animals
- Brain Diseases, Metabolic, Inborn/diagnosis
- Brain Diseases, Metabolic, Inborn/etiology
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/therapy
- Disease Models, Animal
- Humans
- Mice
- Mice, Transgenic
- Models, Biological
- Succinate-Semialdehyde Dehydrogenase/deficiency
- Succinate-Semialdehyde Dehydrogenase/genetics
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Affiliation(s)
- P L Pearl
- Department of Neurology, Children's National Medical Center, George Washington University School of Medicine, 111 Michigan Avenue, NW, Washington, DC 20010-2970, USA.
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Nylen K, Velazquez JLP, Sayed V, Gibson KM, Burnham WM, Snead OC. The effects of a ketogenic diet on ATP concentrations and the number of hippocampal mitochondria in Aldh5a1(-/-) mice. Biochim Biophys Acta Gen Subj 2009; 1790:208-12. [PMID: 19168117 DOI: 10.1016/j.bbagen.2008.12.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 12/14/2008] [Accepted: 12/23/2008] [Indexed: 11/19/2022]
Abstract
BACKGROUND Succinic semialdehyde dehydrogenase (SSADH) deficiency is an inborn error of GABA metabolism characterized clinically by ataxia, psychomotor retardation and seizures. A mouse model of SSADH deficiency, the Aldh5a1(-/-) mouse, has been used to study the pathophysiology and treatment of this disorder. Recent work from our group has shown that the ketogenic diet (KD) is effective in normalizing the Aldh5a1(-/-) phenotype, although the mechanism of the effect remains unclear. METHODS Here, we examine the effects of a KD on the number of hippocampal mitochondria as well as on ATP levels in hippocampus. Electron microscopy was performed to determine the number of mitochondria in the hippocampus of Aldh5a1(-/-) mice. Adenosine triphosphate (ATP) levels were measured in hippocampal extracts. RESULTS Our results show that the KD increases the number of mitochondria in Aldh5a1(-/-) mice. We also show that Aldh5a1(-/-) mice have significant reductions in hippocampal ATP levels as compared to controls, and that the KD restores ATP in mutant mice to normal levels. GENERAL SIGNIFICANCE Taken together, our data suggest that the KD's actions on brain mitochondria may play a role in the diet's ability to treat murine SSADH deficiency.
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Affiliation(s)
- Kirk Nylen
- Neuroscience and Mental Health, 6535 Hill Wing, Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8.
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Shen J, Rothman DL, Behar KL, Xu S. Determination of the glutamate-glutamine cycling flux using two-compartment dynamic metabolic modeling is sensitive to astroglial dilution. J Cereb Blood Flow Metab 2009; 29:108-18. [PMID: 18766194 PMCID: PMC2613170 DOI: 10.1038/jcbfm.2008.102] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the last decade (13)C magnetic resonance spectroscopy ((13)C MRS) combined with the infusion of [1-(13)C]glucose has been used to measure the cerebral rate of the glutamate-glutamine cycle (V(cyc)). However, the effect of the astroglial label dilution pathways on the accuracy and precision of the (13)C MRS measurement of V(cyc) has not been evaluated or realized. In this report, we use the numerical Monte Carlo method to study the effect of astroglial dilution on the reliability of extracting V(cyc) using the neuronal-astroglial two-compartment metabolic model and [1-(13)C]glucose infusion. The results show that omission of the astroglial dilution flux leads to a large loss in the sensitivity of the glutamine turnover curve to V(cyc). When the measured isotopic dilution of cerebral glutamine is accounted for in the analysis, the value of V(cyc) can be precisely and accurately determined.
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Affiliation(s)
- Jun Shen
- 1Molecular Imaging Branch, Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
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Chronic riluzole treatment increases glucose metabolism in rat prefrontal cortex and hippocampus. J Cereb Blood Flow Metab 2008; 28:1892-7. [PMID: 18628780 PMCID: PMC2739056 DOI: 10.1038/jcbfm.2008.78] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Riluzole is believed to modulate glutamatergic function by reducing glutamate release and facilitating astroglial uptake. We measured (13)C labeling in metabolites in prefrontal cortex and hippocampus during a 10 mins infusion of [1-(13)C]glucose in urethane anesthetized rats treated with riluzole (21 days, 4 mg/kg per day, i.p.) or saline. Total and (13)C concentrations of metabolites were determined in extracts using (1)H-[(13)C] NMR spectroscopy. In prefrontal cortex (P<0.05) and hippocampus (P<0.05) riluzole increased (13)C labeling over saline in glutamate-C4 (to 112% and 130%), GABA-C2 (to 142% and 171%), and glutamine-C4 (to 118% and 233%) without affecting total metabolite levels (P>0.2). Our findings indicate that contrary to expectation chronic riluzole enhanced glucose oxidative metabolism and glutamate/glutamine cycling.
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Neurotransmitter alterations in embryonic succinate semialdehyde dehydrogenase (SSADH) deficiency suggest a heightened excitatory state during development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:112. [PMID: 19040727 PMCID: PMC2642797 DOI: 10.1186/1471-213x-8-112] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 11/28/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND SSADH (aldehyde dehydrogenase 5a1 (Aldh5a1); gamma-hydroxybutyric (GHB) aciduria) deficiency is a defect of GABA degradation in which the neuromodulators GABA and GHB accumulate. The human phenotype is that of nonprogressive encephalopathy with prominent bilateral discoloration of the globi pallidi and variable seizures, the latter displayed prominently in Aldh5a1-/- mice with lethal convulsions. Metabolic studies in murine neural tissue have revealed elevated GABA [and its derivatives succinate semialdehyde (SSA), homocarnosine (HC), 4,5-dihydroxyhexanoic acid (DHHA) and guanidinobutyrate (GB)] and GHB [and its analogue D-2-hydroxyglutarate (D-2-HG)] at birth. Because of early onset seizures and the neurostructural anomalies observed in patients, we examined metabolite features during Aldh5a1-/- embryo development. METHODS Embryos were obtained from pregnant dams sacrificed at E (embryo day of life) 10-13, 14-15, 16-17, 18-19 and newborn mice. Intact embryos were extracted and metabolites quantified by isotope dilution mass spectrometry (n = 5-15 subjects, Aldh5a1+/+ and Aldh5a1-/-) for each gestational age group. Data was evaluated using the t test and one-way ANOVA with Tukey post hoc analysis. Significance was set at the 95th centile. RESULTS GABA and DHHA were significantly elevated at all gestational ages in Aldh5a1-/- mice, while GB was increased only late in gestation; SSA was not elevated at any time point. GHB and D-2-HG increased in an approximately linear fashion with gestational age. Correlative studies in human amniotic fluid from SSADH-deficient pregnancies (n = 5) also revealed significantly increased GABA. CONCLUSION Our findings indicate early GABAergic alterations in Aldh5a1-/- mice, possibly exacerbated by other metabolites, which likely induce a heightened excitatory state that may predispose neural networks to epilepsy in these animals.
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Neuropsychiatric morbidity in adolescent and adult succinic semialdehyde dehydrogenase deficiency patients. CNS Spectr 2008; 13:598-605. [PMID: 18622364 PMCID: PMC2562649 DOI: 10.1017/s1092852900016874] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Succinic semialdehyde dehydrogenase (SSADH) deficiency (gamma-hydroxybutyric aciduria) is a rare neurometabolic disorder of gamma-aminobutyric acid degradation. While neurological manifestations, such as developmental delay, are typical during infancy, limited data are available on adolescent and adult symptomatology. METHODS We overview the phenotype of 33 adolescents and adults (10.1-39.5 years of age, mean: 17.1 years, 48% females) with SSADH deficiency. For this purpose, we applied a database with systematic questionnaire-based follow-up data. RESULTS Sixty-six percent of patients (n=21) presented by 6 months of age, 14% from 6-12 months of age, 5% from 1-2 years of age, and 14% from 2-4 years of age, mean age at first symptoms was 11+/-12 months. However, mean age at diagnosis was 6.6+/-6.4 years of age. Presenting symptoms encompassed motor delay, hypotonia, speech delay, autistic features, seizures, and ataxia. Eighty-two percent demonstrated behavioral problems, such as attention deficit, hyperactivity, anxiety, or aggression, and 33% had >or=3 behavior problems. Electroencephalograms showed background slowing or epileptiform discharges in 40% of patients. Treatment approaches are then summarized. CONCLUSION The variable phenotype in SSADH deficiency suggests the likelihood that this disease may be under-diagnosed. Families of patients with SSADH deficiency should be counseled and supported regarding the anticipated persistence of various neuropsychiatric symptoms into adulthood.
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Nylen K, Velazquez JLP, Likhodii SS, Cortez MA, Shen L, Leshchenko Y, Adeli K, Gibson KM, Burnham WM, Snead OC. A ketogenic diet rescues the murine succinic semialdehyde dehydrogenase deficient phenotype. Exp Neurol 2007; 210:449-57. [PMID: 18199435 DOI: 10.1016/j.expneurol.2007.11.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 11/14/2007] [Accepted: 11/15/2007] [Indexed: 10/22/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency is a heritable disorder of GABA degradation characterized by ataxia, psychomotor retardation and seizures. To date, there is no effective treatment for SSADH deficiency. We tested the hypothesis that a ketogenic diet (KD) would improve outcome in an animal model of SSADH deficiency, the SSADH knockout mouse (Aldh5a1-/-). Using a 4:1 ratio of fat to combined carbohydrate and protein KD we set out to compare the general phenotype, in vivo and in vitro electrophysiology and [35S]TBPS binding in both Aldh5a1-/- mice and control (Aldh5a1+/+) mice. We found that the KD prolonged the lifespan of mutant mice by >300% with normalization of ataxia, weight gain and EEG compared to mutants fed a control diet. Aldh5a1-/- mice showed significantly reduced mIPSC frequency in CA1 hippocampal neurons as well as significantly decreased [35S]TBPS binding in all brain areas examined. In KD fed mutants, mIPSC activity normalized and [35S]TBPS binding was restored in the cortex and hippocampus. The KD appears to reverse toward normal the perturbations seen in Aldh5a1-/- mice. Our data suggest that the KD may work in this model by restoring GABAergic inhibition. These data demonstrate a successful experimental treatment for murine SSADH deficiency using a KD, giving promise to the idea that the KD may be successful in the clinical treatment of SSADH deficiency.
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Affiliation(s)
- Kirk Nylen
- Program in Neuroscience and Mental Health, Hospital for Sick Children, and Department of Pharmacology, University of Toronto, Ontario, Canada.
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