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Wang XP, Sun SP, Li YX, Wang L, Dong DJ, Wang JX, Zhao XF. 20-hydroxyecdysone reprograms amino acid metabolism to support the metamorphic development of Helicoverpa armigera. Cell Rep 2023; 42:112644. [PMID: 37310862 DOI: 10.1016/j.celrep.2023.112644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/16/2023] [Accepted: 05/27/2023] [Indexed: 06/15/2023] Open
Abstract
Amino acid metabolism is regulated according to nutrient conditions; however, the mechanism is not fully understood. Using the holometabolous insect cotton bollworm (Helicoverpa armigera) as a model, we report that hemolymph metabolites are greatly changed from the feeding larvae to the wandering larvae and to pupae. Arginine, alpha-ketoglutarate (α-KG), and glutamate (Glu) are identified as marker metabolites of feeding larvae, wandering larvae, and pupae, respectively. Arginine level is decreased by 20-hydroxyecdysone (20E) regulation via repression of argininosuccinate synthetase (Ass) expression and upregulation of arginase (Arg) expression during metamorphosis. α-KG is transformed from Glu by glutamate dehydrogenase (GDH) in larval midgut, which is repressed by 20E. The α-KG is then transformed to Glu by GDH-like in pupal fat body, which is upregulated by 20E. Thus, 20E reprogrammed amino acid metabolism during metamorphosis by regulating gene expression in a stage- and tissue-specific manner to support insect metamorphic development.
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Affiliation(s)
- Xiao-Pei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Shu-Peng Sun
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Yan-Xue Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Lin Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Du-Juan Dong
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jin-Xing Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Xiao-Fan Zhao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao 266237, China.
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2
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Mathioudakis L, Dimovasili C, Bourbouli M, Latsoudis H, Kokosali E, Gouna G, Vogiatzi E, Basta M, Kapetanaki S, Panagiotakis S, Kanterakis A, Boumpas D, Lionis C, Plaitakis A, Simos P, Vgontzas A, Kafetzopoulos D, Zaganas I. Study of Alzheimer's disease- and frontotemporal dementia-associated genes in the Cretan Aging Cohort. Neurobiol Aging 2023; 123:111-128. [PMID: 36117051 DOI: 10.1016/j.neurobiolaging.2022.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/03/2022] [Accepted: 07/04/2022] [Indexed: 02/02/2023]
Abstract
Using exome sequencing, we analyzed 196 participants of the Cretan Aging Cohort (CAC; 95 with Alzheimer's disease [AD], 20 with mild cognitive impairment [MCI], and 81 cognitively normal controls). The APOE ε4 allele was more common in AD patients (23.2%) than in controls (7.4%; p < 0.01) and the PSEN2 p.Arg29His and p.Cys391Arg variants were found in 3 AD and 1 MCI patient, respectively. Also, we found the frontotemporal dementia (FTD)-associated TARDBP gene p.Ile383Val variant in 2 elderly patients diagnosed with AD and in 2 patients, non CAC members, with the amyotrophic lateral sclerosis/FTD phenotype. Furthermore, the p.Ser498Ala variant in the positively selected GLUD2 gene was less frequent in AD patients (2.11%) than in controls (16%; p < 0.01), suggesting a possible protective effect. While the same trend was found in another local replication cohort (n = 406) and in section of the ADNI cohort (n = 808), this finding did not reach statistical significance and therefore it should be considered preliminary. Our results attest to the value of genetic testing to study aged adults with AD phenotype.
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Affiliation(s)
- Lambros Mathioudakis
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Christina Dimovasili
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Mara Bourbouli
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Helen Latsoudis
- Minotech Genomics Facility, Institute of Molecular Biology and Biotechnology (IMBB-FORTH), Heraklion, Crete, Greece
| | - Evgenia Kokosali
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Garyfallia Gouna
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Emmanouella Vogiatzi
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Maria Basta
- University of Crete, Medical School, Psychiatry Department, Heraklion, Crete, Greece
| | - Stefania Kapetanaki
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Simeon Panagiotakis
- University of Crete, Medical School, Internal Medicine Department, Heraklion, Crete, Greece
| | - Alexandros Kanterakis
- Computational BioMedicine Laboratory, Institute of Computer Science, Foundation for Research and Technology - Hellas (ICS-FORTH), Heraklion, Crete, Greece
| | - Dimitrios Boumpas
- University of Crete, Medical School, Internal Medicine Department, Heraklion, Crete, Greece
| | - Christos Lionis
- University of Crete, Medical School, Clinic of Social and Family Medicine, Heraklion, Crete, Greece
| | - Andreas Plaitakis
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece
| | - Panagiotis Simos
- University of Crete, Medical School, Psychiatry Department, Heraklion, Crete, Greece
| | - Alexandros Vgontzas
- University of Crete, Medical School, Psychiatry Department, Heraklion, Crete, Greece
| | - Dimitrios Kafetzopoulos
- Minotech Genomics Facility, Institute of Molecular Biology and Biotechnology (IMBB-FORTH), Heraklion, Crete, Greece
| | - Ioannis Zaganas
- University of Crete, Medical School, Neurology/Neurogenetics Laboratory, Heraklion, Crete, Greece.
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3
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Recent advances on the piezoelectric, electrochemical, and optical biosensors for the detection of protozoan pathogens. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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4
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Bian Y, Hou W, Chen X, Fang J, Xu N, Ruan BH. Glutamate Dehydrogenase as a Promising Target for Hyperinsulinism Hyperammonemia Syndrome Therapy. Curr Med Chem 2021; 29:2652-2672. [PMID: 34525914 DOI: 10.2174/0929867328666210825105342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 11/22/2022]
Abstract
Hyperinsulinism-hyperammonemia syndrome (HHS) is a rare disease characterized by recurrent hypoglycemia and persistent elevation of plasma ammonia, and it can lead to severe epilepsy and permanent brain damage. It has been demonstrated that functional mutations of glutamate dehydrogenase (GDH), an enzyme in the mitochondrial matrix, are responsible for the HHS. Thus, GDH has become a promising target for the small molecule therapeutic intervention of HHS. Several medicinal chemistry studies are currently aimed at GDH, however, to date, none of the compounds reported has been entered clinical trials. This perspective summarizes the progress in the discovery and development of GDH inhibitors, including the pathogenesis of HHS, potential binding sites, screening methods, and research models. Future therapeutic perspectives are offered to provide a reference for discovering potent GDH modulators and encourage additional research that will provide more comprehensive guidance for drug development.
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Affiliation(s)
- Yunfei Bian
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
| | - Wei Hou
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
| | - Xinrou Chen
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
| | - Jinzhang Fang
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
| | - Ning Xu
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
| | - Benfang Helen Ruan
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Hantgzhou 310014. China
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5
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Dimovasili C, Fadouloglou VE, Kefala A, Providaki M, Kotsifaki D, Kanavouras K, Sarrou I, Plaitakis A, Zaganas I, Kokkinidis M. Crystal structure of glutamate dehydrogenase 2, a positively selected novel human enzyme involved in brain biology and cancer pathophysiology. J Neurochem 2021; 157:802-815. [PMID: 33421122 DOI: 10.1111/jnc.15296] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 12/04/2020] [Accepted: 01/06/2021] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Mammalian glutamate dehydrogenase (hGDH1 in human cells) interconverts glutamate to α-ketoglutarate and ammonia while reducing NAD(P) to NAD(P)H. During primate evolution, humans and great apes have acquired hGDH2, an isoenzyme that underwent rapid evolutionary adaptation concomitantly with brain expansion, thereby acquiring unique catalytic and regulatory properties that permitted its function under conditions inhibitory to its ancestor hGDH1. Although the 3D-structures of GDHs, including hGDH1, have been determined, attempts to determine the hGDH2 structure were until recently unsuccessful. Comparison of the hGDH1/hGDH2 structures would enable a detailed understanding of their evolutionary differences. This work aimed at the determination of the hGDH2 crystal structure and the analysis of its functional implications. Recombinant hGDH2 was produced in the Spodoptera frugiperda ovarian cell line Sf21, using the Baculovirus expression system. Purification was achieved via a two-step chromatography procedure. hGDH2 was crystallized, X-ray diffraction data were collected using synchrotron radiation and the structure was determined by molecular replacement. The hGDH2 structure is reported at a resolution of 2.9 Å. The enzyme adopts a novel semi-closed conformation, which is an intermediate between known open and closed GDH1 conformations, differing from both. The structure enabled us to dissect previously reported biochemical findings and to structurally interpret the effects of evolutionary amino acid substitutions, including Arg470His, on ADP affinity. In conclusion, our data provide insights into the structural basis of hGDH2 properties, the functional evolution of hGDH isoenzymes, and open new prospects for drug design, especially for cancer therapeutics.
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Affiliation(s)
- Christina Dimovasili
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece.,Departments of Psychiatry and Neuroscience, Center for Molecular Biology and Genetics of Neurodegeneration, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Vasiliki E Fadouloglou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.,Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Aikaterini Kefala
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.,Department of Biology, University of Crete, Heraklion, Crete, Greece
| | - Mary Providaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Dina Kotsifaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Konstantinos Kanavouras
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece.,Department of Neurology, "G. Gennimatas" General Hospital, Athens, Greece
| | - Iosifina Sarrou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.,Center for Free-Electron Laser Science/DESY, Hamburg, Germany
| | - Andreas Plaitakis
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Zaganas
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Michael Kokkinidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece.,Department of Biology, University of Crete, Heraklion, Crete, Greece
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6
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Proteins moonlighting in tumor metabolism and epigenetics. Front Med 2021; 15:383-403. [PMID: 33387254 DOI: 10.1007/s11684-020-0818-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023]
Abstract
Cancer development is a complicated process controlled by the interplay of multiple signaling pathways and restrained by oxygen and nutrient accessibility in the tumor microenvironment. High plasticity in using diverse nutrients to adapt to metabolic stress is one of the hallmarks of cancer cells. To respond to nutrient stress and to meet the requirements for rapid cell proliferation, cancer cells reprogram metabolic pathways to take up more glucose and coordinate the production of energy and intermediates for biosynthesis. Such actions involve gene expression and activity regulation by the moonlighting function of oncoproteins and metabolic enzymes. The signal - moonlighting protein - metabolism axis facilitates the adaptation of tumor cells under varying environment conditions and can be therapeutically targeted for cancer treatment.
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7
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Hinca SB, Salcedo C, Wagner A, Goldeman C, Sadat E, Aibar MMD, Maechler P, Brodin B, Aldana BI, Helms HCC. Brain endothelial cells metabolize glutamate via glutamate dehydrogenase to replenish TCA-intermediates and produce ATP under hypoglycemic conditions. J Neurochem 2020; 157:1861-1875. [PMID: 33025588 DOI: 10.1111/jnc.15207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/15/2022]
Abstract
The endothelial cells of the blood-brain barrier participate in the regulation of glutamate concentrations in the brain interstitial fluid by taking up brain glutamate. However, endothelial glutamate metabolism has not been characterized, nor is its role in brain glutamate homeostasis and endothelial energy production known. The aim of this study was to investigate endothelial glutamate dehydrogenase (GDH) expression and glutamate metabolism and probe its functional significance. The primary brain endothelial cells were isolated from bovine and mouse brains, and human brain endothelial cells were derived from induced pluripotent stem cells. GDH expression on the protein level and GDH function were investigated in the model systems using western blotting, confocal microscopy, 13 C-glutamate metabolism, and Seahorse assay. In this study, it was shown that GDH was expressed in murine and bovine brain capillaries and in cultured primary mouse and bovine brain endothelial cells as well as in human-induced pluripotent stem cell-derived endothelial cells. The endothelial GDH expression was confirmed in brain capillaries from mice carrying a central nervous system-specific GDH knockout. Endothelial cells from all tested species metabolized 13 C-glutamate to α-ketoglutarate, which subsequently entered the tricarboxylic acid (TCA)-cycle. Brain endothelial cells maintained mitochondrial oxygen consumption rates, when supplied with glutamate alone, whereas glutamate supplied in addition to glucose did not lead to additional oxygen consumption. In conclusion, brain endothelial cells directly take up and metabolize glutamate and utilize the resulting α-ketoglutarate in the tricarboxylic acid cycle to ultimately yield ATP if glucose is unavailable.
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Affiliation(s)
- Sven B Hinca
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claudia Salcedo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Antonie Wagner
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Goldeman
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Edris Sadat
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marco M D Aibar
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, CMU, University of Geneva, Geneva, Switzerland
| | - Birger Brodin
- Department of Pharmacy, 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
| | - Hans C C Helms
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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8
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Glutamate-glutamine homeostasis is perturbed in neurons and astrocytes derived from patient iPSC models of frontotemporal dementia. Mol Brain 2020; 13:125. [PMID: 32928252 PMCID: PMC7491073 DOI: 10.1186/s13041-020-00658-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023] Open
Abstract
Frontotemporal dementia (FTD) is amongst the most prevalent early onset dementias and even though it is clinically, pathologically and genetically heterogeneous, a crucial involvement of metabolic perturbations in FTD pathology is being recognized. However, changes in metabolism at the cellular level, implicated in FTD and in neurodegeneration in general, are still poorly understood. Here we generate induced human pluripotent stem cells (hiPSCs) from patients carrying mutations in CHMP2B (FTD3) and isogenic controls generated via CRISPR/Cas9 gene editing with subsequent neuronal and glial differentiation and characterization. FTD3 neurons show a dysregulation of glutamate-glutamine related metabolic pathways mapped by 13C-labelling coupled to mass spectrometry. FTD3 astrocytes show increased uptake of glutamate whilst glutamate metabolism is largely maintained. Using quantitative proteomics and live-cell metabolic analyses, we elucidate molecular determinants and functional alterations of neuronal and glial energy metabolism in FTD3. Importantly, correction of the mutations rescues such pathological phenotypes. Notably, these findings implicate dysregulation of key enzymes crucial for glutamate-glutamine homeostasis in FTD3 pathogenesis which may underlie vulnerability to neurodegeneration. Neurons derived from human induced pluripotent stem cells (hiPSCs) of patients carrying mutations in CHMP2B (FTD3) display major metabolic alterations compared to CRISPR/Cas9 generated isogenic controls. Using quantitative proteomics, 13C-labelling coupled to mass spectrometry metabolic mapping and seahorse analyses, molecular determinants and functional alterations of neuronal and astrocytic energy metabolism in FTD3 were characterized. Our findings implicate dysregulation of glutamate-glutamine homeostasis in FTD3 pathogenesis. In addition, FTD3 neurons recapitulate glucose hypometabolism observed in FTD patient brains. The impaired mitochondria function found here is concordant with disturbed TCA cycle activity and decreased glycolysis in FTD3 neurons. FTD3 neuronal glutamine hypermetabolism is associated with up-regulation of PAG expression and, possibly, ROS production. Distinct compartments of glutamate metabolism can be suggested for the FTD3 neurons. Endogenous glutamate generated from glutamine via PAG may enter the TCA cycle via AAT (left side of neuron) while exogenous glutamate taken up from the extracellular space may be incorporated into the TCA cycle via GDH (right side of the neuron) FTD3 astrocytic glutamate uptake is upregulated whilst glutamate metabolism is largely maintained. Finally, pharmacological reversal of glutamate hypometabolism manifesting from decreased GDH expression should be explored as a novel therapeutic intervention for treating FTD3.
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9
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Bordone MP, Salman MM, Titus HE, Amini E, Andersen JV, Chakraborti B, Diuba AV, Dubouskaya TG, Ehrke E, Espindola de Freitas A, Braga de Freitas G, Gonçalves RA, Gupta D, Gupta R, Ha SR, Hemming IA, Jaggar M, Jakobsen E, Kumari P, Lakkappa N, Marsh APL, Mitlöhner J, Ogawa Y, Paidi RK, Ribeiro FC, Salamian A, Saleem S, Sharma S, Silva JM, Singh S, Sulakhiya K, Tefera TW, Vafadari B, Yadav A, Yamazaki R, Seidenbecher CI. The energetic brain - A review from students to students. J Neurochem 2019; 151:139-165. [PMID: 31318452 DOI: 10.1111/jnc.14829] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The past 20 years have resulted in unprecedented progress in understanding brain energy metabolism and its role in health and disease. In this review, which was initiated at the 14th International Society for Neurochemistry Advanced School, we address the basic concepts of brain energy metabolism and approach the question of why the brain has high energy expenditure. Our review illustrates that the vertebrate brain has a high need for energy because of the high number of neurons and the need to maintain a delicate interplay between energy metabolism, neurotransmission, and plasticity. Disturbances to the energetic balance, to mitochondria quality control or to glia-neuron metabolic interaction may lead to brain circuit malfunction or even severe disorders of the CNS. We cover neuronal energy consumption in neural transmission and basic ('housekeeping') cellular processes. Additionally, we describe the most common (glucose) and alternative sources of energy namely glutamate, lactate, ketone bodies, and medium chain fatty acids. We discuss the multifaceted role of non-neuronal cells in the transport of energy substrates from circulation (pericytes and astrocytes) and in the supply (astrocytes and microglia) and usage of different energy fuels. Finally, we address pathological consequences of disrupted energy homeostasis in the CNS.
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Affiliation(s)
- Melina Paula Bordone
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Haley E Titus
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Artem V Diuba
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatsiana G Dubouskaya
- Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Eric Ehrke
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Andiara Espindola de Freitas
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, California, USA
| | | | | | | | - Richa Gupta
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Sharon R Ha
- Baylor College of Medicine, Houston, Texas, USA
| | - Isabel A Hemming
- Brain Growth and Disease Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
| | - Minal Jaggar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Punita Kumari
- Defense Institute of Physiology and allied sciences, Defense Research and Development Organization, Timarpur, Delhi, India
| | - Navya Lakkappa
- Department of Pharmacology, JSS college of Pharmacy, Ooty, India
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany
| | - Yuki Ogawa
- The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | | | | | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Suraiya Saleem
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sorabh Sharma
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Joana M Silva
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal
| | - Shripriya Singh
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Kunjbihari Sulakhiya
- Department of Pharmacy, Indira Gandhi National Tribal University, Amarkantak, India
| | - Tesfaye Wolde Tefera
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Behnam Vafadari
- Institute of environmental medicine, UNIKA-T, Technical University of Munich, Munich, Germany
| | - Anuradha Yadav
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Reiji Yamazaki
- Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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10
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Wang X, Liu R, Qu X, Yu H, Chu H, Zhang Y, Zhu W, Wu X, Gao H, Tao B, Li W, Liang J, Li G, Yang W. α-Ketoglutarate-Activated NF-κB Signaling Promotes Compensatory Glucose Uptake and Brain Tumor Development. Mol Cell 2019; 76:148-162.e7. [PMID: 31447391 DOI: 10.1016/j.molcel.2019.07.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/25/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The rapid proliferation of cancer cells and dysregulated vasculature within the tumor leads to limited nutrient accessibility. Cancer cells often rewire their metabolic pathways for adaption to nutrient stress, and the underlying mechanism remains largely unknown. Glutamate dehydrogenase 1 (GDH1) is a key enzyme in glutaminolysis that converts glutamate to α-ketoglutarate (α-KG). Here, we show that, under low glucose, GDH1 is phosphorylated at serine (S) 384 and interacts with RelA and IKKβ. GDH1-produced α-KG directly binds to and activates IKKβ and nuclear factor κB (NF-κB) signaling, which promotes glucose uptake and tumor cell survival by upregulating GLUT1, thereby accelerating gliomagenesis. In addition, GDH1 S384 phosphorylation correlates with the malignancy and prognosis of human glioblastoma. Our finding reveals a unique role of α-KG to directly regulate signal pathway, uncovers a distinct mechanism of metabolite-mediated NF-κB activation, and also establishes the critical role of α-KG-activated NF-κB in brain tumor development.
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Affiliation(s)
- Xiongjun Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Precise Genome Engineering Center, School of Life Sciences, Guangzhou University, Guangzhou 510006, China
| | - Ruilong Liu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiujuan Qu
- Department of Medical Oncology, the First Hospital of China Medical University, Shenyang 110001, China
| | - Hua Yu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Huiying Chu
- Laboratory of Molecular Modeling, State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yajuan Zhang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Wencheng Zhu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xueyuan Wu
- Department of Radiation Oncology, First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang 325000, China
| | - Hong Gao
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Bangbao Tao
- Department of Neurosurgery, XinHua Hospital School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China
| | - Wenfeng Li
- Department of Radiation Oncology, First Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang 325000, China
| | - Ji Liang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Guohui Li
- Laboratory of Molecular Modeling, State Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Weiwei Yang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.
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11
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Remacle N, Forny P, Cudré-Cung HP, Gonzalez-Melo M, do Vale-Pereira S, Henry H, Teav T, Gallart-Ayala H, Braissant O, Baumgartner M, Ballhausen D. New in vitro model derived from brain-specific Mut-/- mice confirms cerebral ammonium accumulation in methylmalonic aciduria. Mol Genet Metab 2018; 124:266-277. [PMID: 29934063 DOI: 10.1016/j.ymgme.2018.06.008] [Citation(s) in RCA: 5] [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: 03/14/2018] [Revised: 06/14/2018] [Accepted: 06/14/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Methylmalonic aciduria (MMAuria) is an inborn error of metabolism leading to neurological deterioration. In this study, we used 3D organotypic brain cell cultures derived from embryos of a brain-specific Mut-/- (brain KO) mouse to investigate mechanisms leading to brain damage. We challenged our in vitro model by a catabolic stress (temperature shift). RESULTS Typical metabolites for MMAuria as well as a massive NH4+ increase were found in the media of brain KO cultures. We investigated different pathways of intracerebral NH4+ production and found increased expression of glutaminase 2 and diminished expression of GDH1 in Mut-/- aggregates. While all brain cell types appeared affected in their morphological development in Mut-/- aggregates, the most pronounced effects were observed on astrocytes showing swollen fibers and cell bodies. Inhibited axonal elongation and delayed myelination of oligodendrocytes were also noted. Most effects were even more pronounced after 48 h at 39 °C. Microglia activation and an increased apoptosis rate suggested degeneration of Mut-/- brain cells. NH4+ accumulation might be the trigger for all observed alterations. We also found a generalized increase of chemokine concentrations in Mut-/- culture media at an early developmental stage followed by a decrease at a later stage. CONCLUSION We proved for the first time that Mut-/- brain cells are indeed able to produce the characteristic metabolites of MMAuria. We confirmed significant NH4+ accumulation in culture media of Mut-/- aggregates, suggesting that intracellular NH4+ concentrations might even be higher, gave first clues on the mechanisms leading to NH4+ accumulation in Mut-/- brain cells, and showed the involvement of neuroinflammatory processes in the neuropathophysiology of MMAuria.
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Affiliation(s)
- Noémie Remacle
- Center of Molecular Diseases, Lausanne University Hospital, Lausanne 1011, Switzerland.
| | - Patrick Forny
- Division of Metabolism, University Children's Hospital Zurich, Zurich 8032, Switzerland
| | - Hong-Phuc Cudré-Cung
- Center of Molecular Diseases, Lausanne University Hospital, Lausanne 1011, Switzerland.
| | - Mary Gonzalez-Melo
- Center of Molecular Diseases, Lausanne University Hospital, Lausanne 1011, Switzerland.
| | - Sónia do Vale-Pereira
- Center of Molecular Diseases, Lausanne University Hospital, Lausanne 1011, Switzerland
| | - Hugues Henry
- Service of Clinical Chemistry, Lausanne University Hospital, Lausanne 1011, Switzerland.
| | - Tony Teav
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne 1011, Switzerland.
| | - Hector Gallart-Ayala
- Metabolomics Unit, Faculty of Biology and Medicine, University of Lausanne, Lausanne 1011, Switzerland.
| | - Olivier Braissant
- Service of Clinical Chemistry, Lausanne University Hospital, Lausanne 1011, Switzerland.
| | - Matthias Baumgartner
- Division of Metabolism, University Children's Hospital Zurich, Zurich 8032, Switzerland.
| | - Diana Ballhausen
- Center of Molecular Diseases, Lausanne University Hospital, Lausanne 1011, Switzerland.
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12
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Mathioudakis L, Bourbouli M, Daklada E, Kargatzi S, Michaelidou K, Zaganas I. Localization of Human Glutamate Dehydrogenases Provides Insights into Their Metabolic Role and Their Involvement in Disease Processes. Neurochem Res 2018; 44:170-187. [PMID: 29943084 DOI: 10.1007/s11064-018-2575-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/11/2018] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
Abstract
Glutamate dehydrogenase (GDH) catalyzes the reversible deamination of L-glutamate to α-ketoglutarate and ammonia. In mammals, GDH contributes to important processes such as amino acid and carbohydrate metabolism, energy production, ammonia management, neurotransmitter recycling and insulin secretion. In humans, two isoforms of GDH are found, namely hGDH1 and hGDH2, with the former being ubiquitously expressed and the latter found mainly in brain, testis and kidney. These two iso-enzymes display highly divergent allosteric properties, especially concerning their basal activity, ADP activation and GTP inhibition. On the other hand, both enzymes are thought to predominantly localize in the mitochondrial matrix, even though alternative localizations have been proposed. To further study the subcellular localization of the two human iso-enzymes, we created HEK293 cell lines stably over-expressing hGDH1 and hGDH2. In these cell lines, immunofluorescence and enzymatic analyses verified the overexpression of both hGDH1 and hGDH2 iso-enzymes, whereas subcellular fractionation followed by immunoblotting showed their predominantly mitochondrial localization. Given that previous studies have only indirectly compared the subcellular localization of the two iso-enzymes, we co-expressed them tagged with different fluorescent dyes (green and red fluorescent protein for hGDH1 and hGDH2, respectively) and found them to co-localize. Despite the wealth of information related to the functional properties of hGDH1 and hGDH2 and the availability of the hGDH1 structure, there is still an ongoing debate concerning their metabolic role and their involvement in disease processes. Data on the localization of hGDHs, as the ones presented here, could contribute to better understanding of the function of these important human enzymes.
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Affiliation(s)
- Lambros Mathioudakis
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Mara Bourbouli
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Elisavet Daklada
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Sofia Kargatzi
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Kleita Michaelidou
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Zaganas
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece. .,Department of Neurology, University Hospital of Heraklion, Heraklion, Crete, Greece.
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13
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Singh NK, Chakma B, Jain P, Goswami P. Protein-Induced Fluorescence Enhancement Based Detection of Plasmodium falciparum Glutamate Dehydrogenase Using Carbon Dot Coupled Specific Aptamer. ACS COMBINATORIAL SCIENCE 2018; 20:350-357. [PMID: 29722521 DOI: 10.1021/acscombsci.8b00021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A novel 90-mer long ssDNA aptamer (NG3) covering a 40-mer random region targeting Plasmodium falciparum glutamate dehydrogenase ( PfGDH) developed through systematic evolution of ligands by exponential enrichment (SELEX) technique. The binding affinity of the aptamer to PfGDH discerned by circular dichroism (CD) was 0.5 ± 0.04 μM. The specificity of the aptamer toward the target was confirmed by gel electrophoresis and CD studies. The presence of two quadruplex forming regions, two big and four small stem loop structures with a δG of -7.99 kcal mol-1 for NG3 were deduced by computational studies. The spherical carbon dots (Cdots) of size 2-4 nm, synthesized by pyrolysis method using l-glutamate as a substrate were covalently linked to the amine modified aptamer. The Cdot with a band gap of 2.8 eV and a quantum yield of 34% produced fluorescence at ∼ λ410 nm when excited at λ320nm. The quantum yield of Cdot-aptamer assembly was increased up to 40% in the presence of the PfGDH in solution. A linear relationship with a dynamic range of 0.5 nM to 25 nM (R2 = 0.98) and a limit of detection (LOD) of 0.48 nM was observed between the fluorescence intensity of the Cdots-aptamer conjugate and the concentration of PfGDH. The method could detect PfGDH with an LOD of 2.85 nM in diluted serum sample. This novel simple, sensitive and specific protein induced fluorescence enhancement based detection of PfGDH has a great potential to develop as a method for malaria detection.
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Affiliation(s)
- Naveen Kumar Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Babina Chakma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Priyamvada Jain
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Pranab Goswami
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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14
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Singh NK, Arya SK, Estrela P, Goswami P. Capacitive malaria aptasensor using Plasmodium falciparum glutamate dehydrogenase as target antigen in undiluted human serum. Biosens Bioelectron 2018; 117:246-252. [PMID: 29909195 DOI: 10.1016/j.bios.2018.06.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/02/2018] [Accepted: 06/08/2018] [Indexed: 12/11/2022]
Abstract
A capacitive aptasensor for detecting the malaria biomarker, Plasmodium falciparum glutamate dehydrogenase (PfGDH), directly in human serum samples developed. A thiolated ssDNA aptamer (NG3) that binds specifically to PfGDH antigen with high affinity (Kd= 79 nM) was used to develop the aptasensor. The aptasensor produced capacitance response at an optimized frequency of 2 Hz in a non-Faradaic electrochemical impedance based signal transduction platform. The aptasensor exhibited a wide dynamic range of 100 fM-100 nM with a limits of detection of 0.77 pM in serum samples. The interference from other predominant malarial biomarkers, namely, Plasmodium falciparum -lactate dehydrogenase and -histidine rich protein-II on the aptasensor was negligible. This PfGDH aptasensor with highly sensitive and label free detection capability has great application potential for diagnosis of asymptotic malaria and monitoring the regression of malaria during treatment regime with antimalarial drugs.
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Affiliation(s)
- Naveen K Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039 Assam, India
| | - Sunil K Arya
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio) and Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Pedro Estrela
- Centre for Biosensors, Bioelectronics and Biodevices (C3Bio) and Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.
| | - Pranab Goswami
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, 781039 Assam, India.
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15
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Distribution of the branched-chain α-ketoacid dehydrogenase complex E1α subunit and glutamate dehydrogenase in the human brain and their role in neuro-metabolism. Neurochem Int 2018; 112:49-58. [DOI: 10.1016/j.neuint.2017.10.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 11/17/2022]
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16
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Waitkus MS, Pirozzi CJ, Moure CJ, Diplas BH, Hansen LJ, Carpenter AB, Yang R, Wang Z, Ingram BO, Karoly ED, Mohney RP, Spasojevic I, McLendon RE, Friedman HS, He Y, Bigner DD, Yan H. Adaptive Evolution of the GDH2 Allosteric Domain Promotes Gliomagenesis by Resolving IDH1 R132H-Induced Metabolic Liabilities. Cancer Res 2017; 78:36-50. [PMID: 29097607 DOI: 10.1158/0008-5472.can-17-1352] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/25/2017] [Accepted: 10/27/2017] [Indexed: 01/13/2023]
Abstract
Hotspot mutations in the isocitrate dehydrogenase 1 (IDH1) gene occur in a number of human cancers and confer a neomorphic enzyme activity that catalyzes the conversion of α-ketoglutarate (αKG) to the oncometabolite D-(2)-hydroxyglutarate (D2HG). In malignant gliomas, IDH1R132H expression induces widespread metabolic reprogramming, possibly requiring compensatory mechanisms to sustain the normal biosynthetic requirements of actively proliferating tumor cells. We used genetically engineered mouse models of glioma and quantitative metabolomics to investigate IDH1R132H-dependent metabolic reprogramming and its potential to induce biosynthetic liabilities that can be exploited for glioma therapy. In gliomagenic neural progenitor cells, IDH1R132H expression increased the abundance of dipeptide metabolites, depleted key tricarboxylic acid cycle metabolites, and slowed progression of murine gliomas. Notably, expression of glutamate dehydrogenase GDH2, a hominoid-specific enzyme with relatively restricted expression to the brain, was critically involved in compensating for IDH1R132H-induced metabolic alterations and promoting IDH1R132H glioma growth. Indeed, we found that recently evolved amino acid substitutions in the GDH2 allosteric domain conferred its nonredundant, glioma-promoting properties in the presence of IDH1 mutation. Our results indicate that among the unique roles for GDH2 in the human forebrain is its ability to limit IDH1R132H-mediated metabolic liabilities, thus promoting glioma growth in this context. Results from this study raise the possibility that GDH2-specific inhibition may be a viable therapeutic strategy for gliomas with IDH mutations.Significance: These findings show that the homonid-specific brain enzyme GDH2 may be essential to mitigate metabolic liabilities created by IDH1 mutations in glioma, with possible implications to leverage its therapeutic management by IDH1 inhibitors. Cancer Res; 78(1); 36-50. ©2017 AACR.
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Affiliation(s)
- Matthew S Waitkus
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Christopher J Pirozzi
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Casey J Moure
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Bill H Diplas
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Landon J Hansen
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Austin B Carpenter
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Rui Yang
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Zhaohui Wang
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | | | | | | | - Ivan Spasojevic
- Department of Medicine - Oncology, Duke University School of Medicine, Durham, North Carolina.,Pharmacokinetics/Pharmacodynamics Core Laboratory, Duke Cancer Institute, Durham, North Carolina
| | - Roger E McLendon
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Henry S Friedman
- Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina.,Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina
| | - Yiping He
- Department of Pathology, Duke University, Durham, North Carolina.,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
| | - Darell D Bigner
- Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina.,Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina
| | - Hai Yan
- Department of Pathology, Duke University, Durham, North Carolina. .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina
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17
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The Glutamate Dehydrogenase Pathway and Its Roles in Cell and Tissue Biology in Health and Disease. BIOLOGY 2017; 6:biology6010011. [PMID: 28208702 PMCID: PMC5372004 DOI: 10.3390/biology6010011] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/10/2017] [Accepted: 01/16/2017] [Indexed: 02/07/2023]
Abstract
Glutamate dehydrogenase (GDH) is a hexameric enzyme that catalyzes the reversible conversion of glutamate to α-ketoglutarate and ammonia while reducing NAD(P)⁺ to NAD(P)H. It is found in all living organisms serving both catabolic and anabolic reactions. In mammalian tissues, oxidative deamination of glutamate via GDH generates α-ketoglutarate, which is metabolized by the Krebs cycle, leading to the synthesis of ATP. In addition, the GDH pathway is linked to diverse cellular processes, including ammonia metabolism, acid-base equilibrium, redox homeostasis (via formation of fumarate), lipid biosynthesis (via oxidative generation of citrate), and lactate production. While most mammals possess a single GDH1 protein (hGDH1 in the human) that is highly expressed in the liver, humans and other primates have acquired, via duplication, an hGDH2 isoenzyme with distinct functional properties and tissue expression profile. The novel hGDH2 underwent rapid evolutionary adaptation, acquiring unique properties that enable enhanced enzyme function under conditions inhibitory to its ancestor hGDH1. These are thought to provide a biological advantage to humans with hGDH2 evolution occurring concomitantly with human brain development. hGDH2 is co-expressed with hGDH1 in human brain, kidney, testis and steroidogenic organs, but not in the liver. In human cerebral cortex, hGDH1 and hGDH2 are expressed in astrocytes, the cells responsible for removing and metabolizing transmitter glutamate, and for supplying neurons with glutamine and lactate. In human testis, hGDH2 (but not hGDH1) is densely expressed in the Sertoli cells, known to provide the spermatids with lactate and other nutrients. In steroid producing cells, hGDH1/2 is thought to generate reducing equivalents (NADPH) in the mitochondria for the biosynthesis of steroidal hormones. Lastly, up-regulation of hGDH1/2 expression occurs in cancer, permitting neoplastic cells to utilize glutamine/glutamate for their growth. In addition, deregulation of hGDH1/2 is implicated in the pathogenesis of several human disorders.
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18
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Nissen JD, Lykke K, Bryk J, Stridh MH, Zaganas I, Skytt DM, Schousboe A, Bak LK, Enard W, Pääbo S, Waagepetersen HS. Expression of the human isoform of glutamate dehydrogenase, hGDH2, augments TCA cycle capacity and oxidative metabolism of glutamate during glucose deprivation in astrocytes. Glia 2016; 65:474-488. [PMID: 28032919 DOI: 10.1002/glia.23105] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 01/06/2023]
Abstract
A key enzyme in brain glutamate homeostasis is glutamate dehydrogenase (GDH) which links carbohydrate and amino acid metabolism mediating glutamate degradation to CO2 and expanding tricarboxylic acid (TCA) cycle capacity with intermediates, i.e. anaplerosis. Humans express two GDH isoforms, GDH1 and 2, whereas most other mammals express only GDH1. hGDH1 is widely expressed in human brain while hGDH2 is confined to astrocytes. The two isoforms display different enzymatic properties and the nature of these supports that hGDH2 expression in astrocytes potentially increases glutamate oxidation and supports the TCA cycle during energy-demanding processes such as high intensity glutamatergic signaling. However, little is known about how expression of hGDH2 affects the handling of glutamate and TCA cycle metabolism in astrocytes. Therefore, we cultured astrocytes from cerebral cortical tissue of hGDH2-expressing transgenic mice. We measured glutamate uptake and metabolism using [3 H]glutamate, while the effect on metabolic pathways of glutamate and glucose was evaluated by use of 13 C and 14 C substrates and analysis by mass spectrometry and determination of radioactively labeled metabolites including CO2 , respectively. We conclude that hGDH2 expression increases capacity for uptake and oxidative metabolism of glutamate, particularly during increased workload and aglycemia. Additionally, hGDH2 expression increased utilization of branched-chain amino acids (BCAA) during aglycemia and caused a general decrease in oxidative glucose metabolism. We speculate, that expression of hGDH2 allows astrocytes to spare glucose and utilize BCAAs during substrate shortages. These findings support the proposed role of hGDH2 in astrocytes as an important fail-safe during situations of intense glutamatergic activity. GLIA 2017;65:474-488.
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Affiliation(s)
- Jakob D Nissen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Kasper Lykke
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jaroslaw Bryk
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 02109, Germany
| | - Malin H Stridh
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Ioannis Zaganas
- Neurology Laboratory, School of Health Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Dorte M Skytt
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Wolfgang Enard
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 02109, Germany
| | - Svante Pääbo
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, 02109, Germany
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, 2100, Denmark
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19
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Abstract
Transient multienzyme and/or multiprotein complexes (metabolons) direct substrates toward specific pathways and can significantly influence the metabolism of glutamate and glutamine in the brain. Glutamate is the primary excitatory neurotransmitter in brain. This neurotransmitter has essential roles in normal brain function including learning and memory. Metabolism of glutamate involves the coordinated activity of astrocytes and neurons and high affinity transporter proteins that are selectively distributed on these cells. This chapter describes known and possible metabolons that affect the metabolism of glutamate and related compounds in the brain, as well as some factors that can modulate the association and dissociation of such complexes, including protein modifications by acylation reactions (e.g., acetylation, palmitoylation, succinylation, SUMOylation, etc.) of specific residues. Development of strategies to modulate transient multienzyme and/or enzyme-protein interactions may represent a novel and promising therapeutic approach for treatment of diseases involving dysregulation of glutamate metabolism.
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20
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Spanaki C, Kotzamani D, Petraki Z, Drakos E, Plaitakis A. Expression of human GLUD1 and GLUD2 glutamate dehydrogenases in steroid producing tissues. Mol Cell Endocrinol 2015; 415:1-11. [PMID: 26241911 DOI: 10.1016/j.mce.2015.07.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 07/19/2015] [Accepted: 07/20/2015] [Indexed: 11/30/2022]
Abstract
Besides the housekeeping glutamate dehydrogenase1 (hGDH1), humans have acquired, via a recent duplication event, a hGDH2 isoenzyme with distinct functional properties and tissue expression profile. GDH catalyzes the reversible deamination of glutamate to α-ketoglutarate while reducing NAD(P) to NAD(P)H. As the generated NADPH can be used in bio-synthetic pathways, we studied here the expression of hGDH1 and hGDH2 in human steroidogenic tissues using specific antibodies. Results revealed high levels of hGDH1 and hGDH2 expression in steroid-producing cells in all tissues studied. While the cellular expression pattern of the two proteins was similar for the adrenal cortex, it was distinct for testis, ovaries and placenta. Functional analyses revealed that steroid hormones interacted differentially with the two isoenzymes. As synthesis of steroid hormones requires NADPH, expression of hGDH1 and hGDH2 in steroidogenic cells may serve their particular metabolic needs.
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Affiliation(s)
- Cleanthe Spanaki
- Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece.
| | - Dimitra Kotzamani
- Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece
| | - Zoe Petraki
- Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece
| | - Elias Drakos
- Department of Pathology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece
| | - Andreas Plaitakis
- Department of Neurology, Faculty of Medicine, School of Health Sciences, University of Crete, Heraklion, Greece
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21
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GDH-Dependent Glutamate Oxidation in the Brain Dictates Peripheral Energy Substrate Distribution. Cell Rep 2015; 13:365-75. [PMID: 26440896 DOI: 10.1016/j.celrep.2015.09.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 08/17/2015] [Accepted: 09/01/2015] [Indexed: 12/27/2022] Open
Abstract
Glucose, the main energy substrate used in the CNS, is continuously supplied by the periphery. Glutamate, the major excitatory neurotransmitter, is foreseen as a complementary energy contributor in the brain. In particular, astrocytes actively take up glutamate and may use it through oxidative glutamate dehydrogenase (GDH) activity. Here, we investigated the significance of glutamate as energy substrate for the brain. Upon glutamate exposure, astrocytes generated ATP in a GDH-dependent way. The observed lack of glutamate oxidation in brain-specific GDH null CnsGlud1(-/-) mice resulted in a central energy-deprivation state with increased ADP/ATP ratios and phospho-AMPK in the hypothalamus. This induced changes in the autonomous nervous system balance, with increased sympathetic activity promoting hepatic glucose production and mobilization of substrates reshaping peripheral energy stores. Our data reveal the importance of glutamate as necessary energy substrate for the brain and the role of central GDH in the regulation of whole-body energy homeostasis.
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Evolution of GLUD2 Glutamate Dehydrogenase Allows Expression in Human Cortical Neurons. Mol Neurobiol 2015; 53:5140-8. [PMID: 26399640 DOI: 10.1007/s12035-015-9429-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
Abstract
Human hGDH2 arose via duplication in the apes and driven by positive selection acquired enhanced catalytic ability under conditions inhibitory to its precursor hGDH1 (common to all mammals). To explore the biological advantage provided by the novel enzyme, we studied, by immunohistochemistry (IHC) and immunofluorescence (IF), hGDH1 and hGDH2 expression in the human brain. Studies on human cortical tissue using anti-hGDH1-specific antibody revealed that hGDH1 was expressed in glial cells (astrocytes, oligodendrocytes, and oligodendrocyte precursors) with neurons being devoid of hGDH1 staining. In contrast, an hGDH2-specific antiserum labeled both astrocytes and neurons. Specifically, hGDH2 immunoreactivity was found in the cytoplasm of large neuronal cells within coarse structures resembling mitochondria. These were distributed either in the perikaryon or in the cell periphery. Double immunofluorescence (IF) suggested that the latter represented hGDH2-labeled mitochondria of presynaptic nerve terminals. Hence, hGDH2 evolution bestowed large human neurons with enhanced glutamate metabolizing capacity, thus strengthening cortical excitatory transmission.
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Dimovasili C, Aschner M, Plaitakis A, Zaganas I. Differential interaction of hGDH1 and hGDH2 with manganese: Implications for metabolism and toxicity. Neurochem Int 2015; 88:60-5. [PMID: 25837286 DOI: 10.1016/j.neuint.2015.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
Abstract
Manganese (Mn) is an essential trace element that serves as co-factor for many important mammalian enzymes. In humans, the importance of this cation is highlighted by the fact that low levels of Mn cause developmental and metabolic abnormalities and, on the other hand, chronic exposure to excessive amounts of Mn is characterized by neurotoxicity, possibly mediated by perturbation of astrocytic mitochondrial energy metabolism. Here we sought to study the effect of Mn on the two human glutamate dehydrogenases (hGDH1 and hGDH2, respectively), key mitochondrial enzymes involved in numerous cellular processes, including mitochondrial metabolism, glutamate homeostasis and neurotransmission, and cell signaling. Our studies showed that, compared to magnesium (Mg) and calcium (Ca), Mn exerted a significant inhibitory effect on both human isoenzymes with hGDH2 being more sensitive than hGDH1, especially under conditions of low ADP levels. Specifically, in the presence of 0.25 mM ADP, the Mn IC50 was 1.14 ± 0.02 mM and 1.54 ± 0.08 mM for hGDH2 and for hGDH1, respectively (p = 0.0001). Increasing Mn levels potentiated this differential effect, with 3 mM Mn inhibiting hGDH2 by 96.5% and hGDH1 by 70.2%. At 1 mM ADP, the Mn IC50 was 1.84 ± 0.02 mM and 2.04 ± 0.07 mM (p = 0.01) for hGDH2 and hGDH1, respectively, with 3 mM Mn inhibiting hGDH2 by 93.6% and hGDH1 by 70.9%. These results were due to the sigmoidal inhibitory curve of Mn that was more pronounced for hGDH2 than for hGDH1. Indeed, at 0.25 mM, the Hill coefficient value was higher for hGDH2 (3.42 ± 0.20) than for hGDH1 (1.94 ± 0.25; p = 0.0002) indicating that interaction of Mn with hGDH2 was substantially more co-operative than for hGDH1. These findings, showing an enhanced sensitivity of the hGDH2 isoenzyme to Mn, especially at low ADP levels, might be of pathophysiological relevance under conditions of Mn neurotoxicity.
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Affiliation(s)
- Christina Dimovasili
- Neurology Laboratory, School of Health Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Andreas Plaitakis
- Neurology Laboratory, School of Health Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Ioannis Zaganas
- Neurology Laboratory, School of Health Sciences, Faculty of Medicine, University of Crete, Heraklion, Crete, Greece.
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Localization of SUCLA2 and SUCLG2 subunits of succinyl CoA ligase within the cerebral cortex suggests the absence of matrix substrate-level phosphorylation in glial cells of the human brain. J Bioenerg Biomembr 2014; 47:33-41. [PMID: 25370487 DOI: 10.1007/s10863-014-9586-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/21/2014] [Indexed: 10/24/2022]
Abstract
We have recently shown that the ATP-forming SUCLA2 subunit of succinyl-CoA ligase, an enzyme of the citric acid cycle, is exclusively expressed in neurons of the human cerebral cortex; GFAP- and S100-positive astroglial cells did not exhibit immunohistoreactivity or in situ hybridization reactivity for either SUCLA2 or the GTP-forming SUCLG2. However, Western blotting of post mortem samples revealed a minor SUCLG2 immunoreactivity. In the present work we sought to identify the cell type(s) harboring SUCLG2 in paraformaldehyde-fixed, free-floating surgical human cortical tissue samples. Specificity of SUCLG2 antiserum was supported by co-localization with mitotracker orange staining of paraformaldehyde-fixed human fibroblast cultures, delineating the mitochondrial network. In human cortical tissue samples, microglia and oligodendroglia were identified by antibodies directed against Iba1 and myelin basic protein, respectively. Double immunofluorescence for SUCLG2 and Iba1 or myelin basic protein exhibited no co-staining; instead, SUCLG2 appeared to outline the cerebral microvasculature. In accordance to our previous work there was no co-localization of SUCLA2 immunoreactivity with either Iba1 or myelin basic protein. We conclude that SUCLG2 exist only in cells forming the vasculature or its contents in the human brain. The absence of SUCLA2 and SUCLG2 in human glia is in compliance with the presence of alternative pathways occurring in these cells, namely the GABA shunt and ketone body metabolism which do not require succinyl CoA ligase activity, and glutamate dehydrogenase 1, an enzyme exhibiting exquisite sensitivity to inhibition by GTP.
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The Odyssey of a Young Gene: Structure–Function Studies in Human Glutamate Dehydrogenases Reveal Evolutionary-Acquired Complex Allosteric Regulation Mechanisms. Neurochem Res 2014; 39:471-86. [DOI: 10.1007/s11064-014-1251-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 01/24/2014] [Accepted: 01/29/2014] [Indexed: 01/13/2023]
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Heterogeneous Cellular Distribution of Glutamate Dehydrogenase in Brain and in Non-neural Tissues. Neurochem Res 2014; 39:500-15. [DOI: 10.1007/s11064-013-1235-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 12/27/2013] [Accepted: 12/30/2013] [Indexed: 01/30/2023]
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The discovery of human of GLUD2 glutamate dehydrogenase and its implications for cell function in health and disease. Neurochem Res 2013; 39:460-70. [PMID: 24352816 DOI: 10.1007/s11064-013-1227-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/07/2013] [Accepted: 12/11/2013] [Indexed: 10/25/2022]
Abstract
While the evolutionary changes that led to traits unique to humans remain unclear, there is increasing evidence that enrichment of the human genome through DNA duplication processes may have contributed to traits such as bipedal locomotion, higher cognitive abilities and language. Among the genes that arose through duplication in primates during the period of increased brain development was GLUD2, which encodes the hGDH2 isoform of glutamate dehydrogenase expressed in neural and other tissues. Glutamate dehydrogenase GDH is an enzyme central to the metabolism of glutamate, the main excitatory neurotransmitter in mammalian brain involved in a multitude of CNS functions, including cognitive processes. In nerve tissue GDH is expressed in astrocytes that wrap excitatory synapses, where it is thought to play a role in the metabolic fate of glutamate removed from the synaptic cleft during excitatory transmission. Expression of GDH rises sharply during postnatal brain development, coinciding with nerve terminal sprouting and synaptogenesis. Compared to the original hGDH1 (encoded by the GLUD1 gene), which is potently inhibited by GTP generated by the Krebs cycle, hGDH2 can function independently of this energy switch. In addition, hGDH2 can operate efficiently in the relatively acidic environment that prevails in astrocytes following glutamate uptake. This adaptation is thought to provide a biological advantage by enabling enhanced enzyme catalysis under intense excitatory neurotransmission. While the novel protein may help astrocytes to handle increased loads of transmitter glutamate, dissociation of hGDH2 from GTP control may render humans vulnerable to deregulation of this enzyme's function. Here we will retrace the cloning and characterization of the novel GLUD2 gene and the potential implications of this discovery in the understanding of mechanisms that permitted the brain and other organs that express hGDH2 to fine-tune their functions in order to meet new challenging demands. In addition, the potential role of gain-of-function of hGDH2 variants in human neurodegenerative processes will be considered.
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Abstract
In vitro and in vivo studies have shown that glutamate can be oxidized for energy by brain astrocytes. The ability to harvest the energy from glutamate provides astrocytes with a mechanism to offset the high ATP cost of the uptake of glutamate from the synaptic cleft. This brief review focuses on oxidative metabolism of glutamate by astrocytes, the specific pathways involved in the complete oxidation of glutamate and the energy provided by each reaction.
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Affiliation(s)
- Mary C. McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- *Correspondence: Mary C. McKenna, Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, 655 West Baltimore Street, Room 13-019 BRB, Baltimore, MD 21201, USA e-mail:
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Zaganas I, Pajęcka K, Wendel Nielsen C, Schousboe A, Waagepetersen HS, Plaitakis A. The effect of pH and ADP on ammonia affinity for human glutamate dehydrogenases. Metab Brain Dis 2013; 28:127-31. [PMID: 23420347 DOI: 10.1007/s11011-013-9382-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 01/23/2013] [Indexed: 11/26/2022]
Abstract
Glutamate dehydrogenase (GDH) uses ammonia to reversibly convert α-ketoglutarate to glutamate using NADP(H) and NAD(H) as cofactors. While GDH in most mammals is encoded by a single GLUD1 gene, humans and other primates have acquired a GLUD2 gene with distinct tissue expression profile. The two human isoenzymes (hGDH1 and hGDH2), though highly homologous, differ markedly in their regulatory properties. Here we obtained hGDH1 and hGDH2 in recombinant form and studied their Km for ammonia in the presence of 1.0 mM ADP. The analyses showed that lowering the pH of the buffer (from 8.0 to 7.0) increased the Km for ammonia substantially (hGDH1: from 12.8 ± 1.4 mM to 57.5 ± 1.6 mM; hGDH2: from 14.7 ± 1.6 mM to 62.2 ± 1.7 mM), thus essentially precluding reductive amination. Moreover, lowering the ADP concentration to 0.1 mM not only increased the K0.5 [NH4 (+)] of hGDH2, but also introduced a positive cooperative binding phenomenon in this isoenzyme. Hence, intra-mitochondrial acidification, as occurring in astrocytes during glutamatergic transmission should favor the oxidative deamination of glutamate. Similar considerations apply to the handling of glutamate by the proximal convoluted tubules of the kidney during systemic acidosis. The reverse could apply for conditions of local or systemic hyperammonemia or alkalosis.
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Affiliation(s)
- Ioannis Zaganas
- Neurology Laboratory, Medical School, University of Crete, Heraklion, Crete, Greece.
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Plaitakis A, Zaganas I, Spanaki C. Deregulation of glutamate dehydrogenase in human neurologic disorders. J Neurosci Res 2013; 91:1007-17. [PMID: 23463419 DOI: 10.1002/jnr.23176] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 10/15/2012] [Accepted: 10/19/2012] [Indexed: 11/09/2022]
Abstract
Mammalian glutamate dehydrogenase is an allosterically regulated enzyme that is central to glutamate metabolism. It contributes to important cellular processes, including Krebs cycle anaplerotic mechanisms, energy production, and ammonia homeostasis. In addition to this housekeeping hGDH1, humans have acquired through duplication an hGDH2 isoenzyme expressed in neural tissues with distinct regulatory properties. There is increasing evidence that deregulation of human GDHs leads to human disorders. Thus, in hGDH1, regulatory mutations that attenuate GTP inhibition can result in the hyperinsulinism/hyperammonemia syndrome, which is often associated with epileptic seizures, mental retardation, and generalized dystonia. Also, transgenic overexpression of GLUD1 in neurons has resulted in age-dependent degeneration of the CA1 behippocampal region, associated with upregulation of α-synuclein and other proteins linked to major human movement disorders. With regard to hGDH2, a rare T1492G variation in the GLUD2 gene, resulting in substitution of Ala for Ser445 in the regulatory domain of hGDH2, interacts significantly with Parkinson's disease (PD) onset. In two independent Greek and one North American PD cohorts, Ser445Ala hemizygous males, but not heterozygous females, developed PD 6-13 years earlier than subjects with other genotypes. The Ala445-hGDH2 variant displays increased catalytic activity that is amenable to inhibition by estrogens. Enhanced glutamate oxidation by Ala445-hGDH2 is thought to accelerate nigral cell degeneration in hemizygous males, and inhibition of the overactive variant by estrogens may protect heterozygous females. Hence, deregulation of hGDH1 and hGDH2 may play a role in degenerative processes, so these observations identify novel targets for therapeutic intervention in human disorders.
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Affiliation(s)
- Andreas Plaitakis
- Department of Neurology, Medical School, University of Crete, 71003 Heraklion, Crete, Greece.
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Intertissue Differences for the Role of Glutamate Dehydrogenase in Metabolism. Neurochem Res 2013; 39:516-26. [DOI: 10.1007/s11064-013-0998-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/24/2013] [Accepted: 02/01/2013] [Indexed: 11/26/2022]
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Bringmann A, Grosche A, Pannicke T, Reichenbach A. GABA and Glutamate Uptake and Metabolism in Retinal Glial (Müller) Cells. Front Endocrinol (Lausanne) 2013; 4:48. [PMID: 23616782 PMCID: PMC3627989 DOI: 10.3389/fendo.2013.00048] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/04/2013] [Indexed: 12/11/2022] Open
Abstract
Müller cells, the principal glial cells of the retina, support the synaptic activity by the uptake and metabolization of extracellular neurotransmitters. Müller cells express uptake and exchange systems for various neurotransmitters including glutamate and γ-aminobutyric acid (GABA). Müller cells remove the bulk of extracellular glutamate in the inner retina and contribute to the glutamate clearance around photoreceptor terminals. By the uptake of glutamate, Müller cells are involved in the shaping and termination of the synaptic activity, particularly in the inner retina. Reactive Müller cells are neuroprotective, e.g., by the clearance of excess extracellular glutamate, but may also contribute to neuronal degeneration by a malfunctioning or even reversal of glial glutamate transporters, or by a downregulation of the key enzyme, glutamine synthetase. This review summarizes the present knowledge about the role of Müller cells in the clearance and metabolization of extracellular glutamate and GABA. Some major pathways of GABA and glutamate metabolism in Müller cells are described; these pathways are involved in the glutamate-glutamine cycle of the retina, in the defense against oxidative stress via the production of glutathione, and in the production of substrates for the neuronal energy metabolism.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Antje Grosche
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Thomas Pannicke
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
| | - Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of LeipzigLeipzig, Germany
- *Correspondence: Andreas Reichenbach, Paul Flechsig Institute of Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany. e-mail:
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