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Cantando I, Centofanti C, D’Alessandro G, Limatola C, Bezzi P. Metabolic dynamics in astrocytes and microglia during post-natal development and their implications for autism spectrum disorders. Front Cell Neurosci 2024; 18:1354259. [PMID: 38419654 PMCID: PMC10899402 DOI: 10.3389/fncel.2024.1354259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/02/2024] [Indexed: 03/02/2024] Open
Abstract
Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by elusive underlying mechanisms. Recent attention has focused on the involvement of astrocytes and microglia in ASD pathology. These glial cells play pivotal roles in maintaining neuronal homeostasis, including the regulation of metabolism. Emerging evidence suggests a potential association between ASD and inborn errors of metabolism. Therefore, gaining a comprehensive understanding of the functions of microglia and astrocytes in ASD is crucial for the development of effective therapeutic interventions. This review aims to provide a summary of the metabolism of astrocytes and microglia during post-natal development and the evidence of disrupted metabolic pathways in ASD, with particular emphasis on those potentially important for the regulation of neuronal post-natal maturation by astrocytes and microglia.
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Affiliation(s)
- Iva Cantando
- Department of Fundamental Neurosciences (DNF), University of Lausanne, Lausanne, Switzerland
| | - Cristiana Centofanti
- Department of Fundamental Neurosciences (DNF), University of Lausanne, Lausanne, Switzerland
| | - Giuseppina D’Alessandro
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
- Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed Via Atinese 18, Pozzilli, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
- Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed Via Atinese 18, Pozzilli, Italy
| | - Paola Bezzi
- Department of Fundamental Neurosciences (DNF), University of Lausanne, Lausanne, Switzerland
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
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2
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Colucci ACM, Tassinari ID, Loss EDS, de Fraga LS. History and Function of the Lactate Receptor GPR81/HCAR1 in the Brain: A Putative Therapeutic Target for the Treatment of Cerebral Ischemia. Neuroscience 2023; 526:144-163. [PMID: 37391123 DOI: 10.1016/j.neuroscience.2023.06.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/21/2023] [Accepted: 06/24/2023] [Indexed: 07/02/2023]
Abstract
GPR81 is a G-protein coupled receptor (GPCR) discovered in 2001, but deorphanized only 7 years later, when its affinity for lactate as an endogenous ligand was demonstrated. More recently, GPR81 expression and distribution in the brain were also confirmed and the function of lactate as a volume transmitter has been suggested since then. These findings shed light on a new function of lactate acting as a signaling molecule in the central nervous system, in addition to its well-known role as a metabolic fuel for neurons. GPR81 seems to act as a metabolic sensor, coupling energy metabolism, synaptic activity, and blood flow. Activation of this receptor leads to Gi-mediated downregulation of adenylyl cyclase and subsequent reduction in cAMP levels, regulating several downstream pathways. Recent studies have also suggested the potential role of lactate as a neuroprotective agent, mainly under brain ischemic conditions. This effect is usually attributed to the metabolic role of lactate, but the underlying mechanisms need further investigation and could be related to lactate signaling via GPR81. The activation of GPR81 showed promising results for neuroprotection: it modulates many processes involved in the pathophysiology of ischemia. In this review, we summarize the history of GPR81, starting with its deorphanization; then, we discuss GPR81 expression and distribution, signaling transduction cascades, and neuroprotective roles. Lastly, we propose GPR81 as a potential target for the treatment of cerebral ischemia.
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Affiliation(s)
- Anna Clara Machado Colucci
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil
| | - Isadora D'Ávila Tassinari
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil
| | - Eloísa da Silveira Loss
- Laboratório de Endocrinologia Experimental (LABENEX), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil
| | - Luciano Stürmer de Fraga
- Laboratório de Neurobiologia e Metabolismo (NeuroMet), Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, lab. 660, Porto Alegre, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Rua Ramiro Barcelos, 2600, Porto Alegre, Brazil; Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, Porto Alegre, Brazil.
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Aboouf MA, Thiersch M, Soliz J, Gassmann M, Schneider Gasser EM. The Brain at High Altitude: From Molecular Signaling to Cognitive Performance. Int J Mol Sci 2023; 24:10179. [PMID: 37373327 DOI: 10.3390/ijms241210179] [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: 04/27/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
The brain requires over one-fifth of the total body oxygen demand for normal functioning. At high altitude (HA), the lower atmospheric oxygen pressure inevitably challenges the brain, affecting voluntary spatial attention, cognitive processing, and attention speed after short-term, long-term, or lifespan exposure. Molecular responses to HA are controlled mainly by hypoxia-inducible factors. This review aims to summarize the cellular, metabolic, and functional alterations in the brain at HA with a focus on the role of hypoxia-inducible factors in controlling the hypoxic ventilatory response, neuronal survival, metabolism, neurogenesis, synaptogenesis, and plasticity.
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Affiliation(s)
- Mostafa A Aboouf
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Jorge Soliz
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC G1V 4G5, Canada
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Edith M Schneider Gasser
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, 8057 Zurich, Switzerland
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC G1V 4G5, Canada
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057 Zurich, Switzerland
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IWANAGA T, TAKAHASHI-IWANAGA H, NIO-KOBAYASHI J, EBARA S. Structure and barrier functions of the perineurium and its relationship with associated sensory corpuscles: A review. Biomed Res 2022; 43:145-159. [DOI: 10.2220/biomedres.43.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Toshihiko IWANAGA
- Department of Anatomy, Hokkaido University Graduate School of Medicine
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5
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Stanescu S, Bravo-Alonso I, Belanger-Quintana A, Pérez B, Medina-Diaz M, Ruiz-Sala P, Flores NP, Buenache R, Arrieta F, Rodríguez-Pombo P. Mitochondrial bioenergetic is impaired in Monocarboxylate transporter 1 deficiency: a new clinical case and review of the literature. Orphanet J Rare Dis 2022; 17:243. [PMID: 35729663 PMCID: PMC9215049 DOI: 10.1186/s13023-022-02389-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/06/2022] [Indexed: 12/03/2022] Open
Abstract
Background Monocarboxylate transporter 1 (MCT1) deficiency has recently been described as a rare cause of recurrent ketosis, the result of impaired ketone utilization in extrahepatic tissues. To date, only six patients with this condition have been identified, and clinical and biochemical details remain incomplete. Results The present work reports a patient suffering from severe, recurrent episodes of metabolic acidosis and psychomotor delay, showing a pathogenic loss-of-function variation c.747_750del in homozygosity in SLC16A1 (which codes for MCT1). Persistent ketotic and lactic acidosis was accompanied by an abnormal excretion of organic acids related to redox balance disturbances. Together with an altered bioenergetic profile detected in patient-derived fibroblasts, this suggests possible mitochondrial dysfunction. Brain MRI revealed extensive, diffuse bilateral, symmetric signal alterations for the subcortical white matter and basal ganglia, together with corpus callosum agenesia. Conclusions These findings suggest that the clinical spectrum of MCT1 deficiency not only involves recurrent atacks of ketoacidosis, but may also cause lactic acidosis and neuromotor delay with a distinctive neuroimaging pattern including agenesis of corpus callosum and other brain signal alterations. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-022-02389-4.
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Affiliation(s)
- Sinziana Stanescu
- Unidad de Enfermedades Metabólicas, Hospital Universitario Ramón y Cajal, IRYCIS, Crta de Colmenar Viejo, km 9,100, 28034, Madrid, Spain.
| | - Irene Bravo-Alonso
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CIBERER, IdiPAZ, C/Francisco Tomás y Valiente, 7, 28049, Madrid, Spain
| | - Amaya Belanger-Quintana
- Unidad de Enfermedades Metabólicas, Hospital Universitario Ramón y Cajal, IRYCIS, Crta de Colmenar Viejo, km 9,100, 28034, Madrid, Spain
| | - Belen Pérez
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CIBERER, IdiPAZ, C/Francisco Tomás y Valiente, 7, 28049, Madrid, Spain
| | - Montserrat Medina-Diaz
- Department of Neuroradiology, Hospital Universitario Ramón y Cajal, IRYCIS, Crta de Colmenar Viejo, km 9,100, 28034, Madrid, Spain
| | - Pedro Ruiz-Sala
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular, Universidad Autónoma de Madrid, CIBERER, IdiPAZ, C/Francisco Tomás y Valiente, 7, 28049, Madrid, Spain
| | - Nathaly Paola Flores
- Paediatric Department, Hospital General La Mancha Centro, Av. Constitución, 3, 13600, Alcázar de San Juan, Ciudad Real, Spain
| | - Raquel Buenache
- Neuropediatric Department, Hospital Universitario Ramón y Cajal, IRYCIS, Crta de Colmenar Viejo, km 9,100, 28034, Madrid, Spain
| | - Francisco Arrieta
- Unidad de Enfermedades Metabólicas, Hospital Universitario Ramón y Cajal, IRYCIS, CIBER-OBN, Crta de Colmenar Viejo, km 9,100, 28034, Madrid, Spain
| | - Pilar Rodríguez-Pombo
- Centro de Diagnóstico de Enfermedades Moleculares, Centro de Biología Molecular Severo Ochoa, UAM-CSIC, CIBERER, IdiPAZ, C/Francisco Tomás y Valiente, 7, 28049, Madrid, Spain
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Jurcau A. Insights into the Pathogenesis of Neurodegenerative Diseases: Focus on Mitochondrial Dysfunction and Oxidative Stress. Int J Mol Sci 2021; 22:11847. [PMID: 34769277 PMCID: PMC8584731 DOI: 10.3390/ijms222111847] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/12/2022] Open
Abstract
As the population ages, the incidence of neurodegenerative diseases is increasing. Due to intensive research, important steps in the elucidation of pathogenetic cascades have been made and significantly implicated mitochondrial dysfunction and oxidative stress. However, the available treatment in Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis is mainly symptomatic, providing minor benefits and, at most, slowing down the progression of the disease. Although in preclinical setting, drugs targeting mitochondrial dysfunction and oxidative stress yielded encouraging results, clinical trials failed or had inconclusive results. It is likely that by the time of clinical diagnosis, the pathogenetic cascades are full-blown and significant numbers of neurons have already degenerated, making it impossible for mitochondria-targeted or antioxidant molecules to stop or reverse the process. Until further research will provide more efficient molecules, a healthy lifestyle, with plenty of dietary antioxidants and avoidance of exogenous oxidants may postpone the onset of neurodegeneration, while familial cases may benefit from genetic testing and aggressive therapy started in the preclinical stage.
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Affiliation(s)
- Anamaria Jurcau
- Department of Psycho-Neurosciences and Rehabilitation, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania;
- Neurology Ward, Clinical Municipal Hospital “dr. G. Curteanu” Oradea, 410154 Oradea, Romania
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Bessières B, Cruz E, Alberini CM. Metabolomic profiling reveals a differential role for hippocampal glutathione reductase in infantile memory formation. eLife 2021; 10:68590. [PMID: 34825649 PMCID: PMC8626085 DOI: 10.7554/elife.68590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 11/09/2021] [Indexed: 01/12/2023] Open
Abstract
The metabolic mechanisms underlying the formation of early-life episodic memories remain poorly characterized. Here, we assessed the metabolomic profile of the rat hippocampus at different developmental ages both at baseline and following episodic learning. We report that the hippocampal metabolome significantly changes over developmental ages and that learning regulates differential arrays of metabolites according to age. The infant hippocampus had the largest number of significant changes following learning, with downregulation of 54 metabolites. Of those, a large proportion was associated with the glutathione-mediated cellular defenses against oxidative stress. Further biochemical, molecular, and behavioral assessments revealed that infantile learning evokes a rapid and persistent increase in the activity of neuronal glutathione reductase, the enzyme that regenerates reduced glutathione from its oxidized form. Inhibition of glutathione reductase selectively impaired long-term memory formation in infant but not in juvenile and adult rats, confirming its age-specific role. Thus, metabolomic profiling revealed that the hippocampal glutathione-mediated antioxidant pathway is differentially required for the formation of infantile memory.
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Affiliation(s)
| | - Emmanuel Cruz
- Center for Neural Science, New York UniversityNew YorkUnited States
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Błaszczyk JW. Energy Metabolism Decline in the Aging Brain-Pathogenesis of Neurodegenerative Disorders. Metabolites 2020; 10:metabo10110450. [PMID: 33171879 PMCID: PMC7695180 DOI: 10.3390/metabo10110450] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/31/2020] [Accepted: 11/04/2020] [Indexed: 12/14/2022] Open
Abstract
There is a growing body of evidencethat indicates that the aging of the brain results from the decline of energy metabolism. In particular, the neuronal metabolism of glucose declines steadily, resulting in a growing deficit of adenosine triphosphate (ATP) production-which, in turn, limits glucose access. This vicious circle of energy metabolism at the cellular level is evoked by a rising deficiency of nicotinamide adenine dinucleotide (NAD) in the mitochondrial salvage pathway and subsequent impairment of the Krebs cycle. A decreasing NAD level also impoverishes the activity of NAD-dependent enzymes that augments genetic errors and initiate processes of neuronal degeneration and death.This sequence of events is characteristic of several brain structures in which neurons have the highest energy metabolism. Neurons of the cerebral cortex and basal ganglia with long unmyelinated axons and these with numerous synaptic junctions are particularly prone to senescence and neurodegeneration. Unfortunately, functional deficits of neurodegeneration are initially well-compensated, therefore, clinical symptoms are recognized too late when the damages to the brain structures are already irreversible. Therefore, future treatment strategies in neurodegenerative disorders should focus on energy metabolism and compensation age-related NAD deficit in neurons. This review summarizes the complex interrelationships between metabolic processes on the systemic and cellular levels and provides directions on how to reduce the risk of neurodegeneration and protect the elderly against neurodegenerative diseases.
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Affiliation(s)
- Janusz Wiesław Błaszczyk
- Department of Human Motor Behavior, Jerzy Kukuczka Academy of Physical Education, 40-065 Katowice, Poland
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Deme P, Rojas C, Slusher BS, Rais R, Afghah Z, Geiger JD, Haughey NJ. Bioenergetic adaptations to HIV infection. Could modulation of energy substrate utilization improve brain health in people living with HIV-1? Exp Neurol 2020; 327:113181. [PMID: 31930991 PMCID: PMC7233457 DOI: 10.1016/j.expneurol.2020.113181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/18/2022]
Abstract
The human brain consumes more energy than any other organ in the body and it relies on an uninterrupted supply of energy in the form of adenosine triphosphate (ATP) to maintain normal cognitive function. This constant supply of energy is made available through an interdependent system of metabolic pathways in neurons, glia and endothelial cells that each have specialized roles in the delivery and metabolism of multiple energetic substrates. Perturbations in brain energy metabolism is associated with a number of different neurodegenerative conditions including impairments in cognition associated with infection by the Human Immunodeficiency Type 1 Virus (HIV-1). Adaptive changes in brain energy metabolism are apparent early following infection, do not fully normalize with the initiation of antiretroviral therapy (ART), and often worsen with length of infection and duration of anti-retroviral therapeutic use. There is now a considerable amount of cumulative evidence that suggests mild forms of cognitive impairments in people living with HIV-1 (PLWH) may be reversible and are associated with specific modifications in brain energy metabolism. In this review we discuss brain energy metabolism with an emphasis on adaptations that occur in response to HIV-1 infection. The potential for interventions that target brain energy metabolism to preserve or restore cognition in PLWH are also discussed.
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Affiliation(s)
- Pragney Deme
- The Johns Hopkins University School of Medicine, Department of Neurology, United States
| | - Camilo Rojas
- The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States
| | - Barbara S Slusher
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of The Solomon H. Snyder Department of Neuroscience, United States; The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States
| | - Raina Rais
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of The Solomon H. Snyder Department of Neuroscience, United States; The Johns Hopkins University School of Medicine, Department of Comparative Medicine and Pathobiology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States
| | - Zahra Afghah
- The University of North Dakota School of Medicine and Health Sciences, Department of Biomedical Sciences, United States
| | - Jonathan D Geiger
- The University of North Dakota School of Medicine and Health Sciences, Department of Biomedical Sciences, United States
| | - Norman J Haughey
- The Johns Hopkins University School of Medicine, Department of Neurology, United States; The Johns Hopkins University School of Medicine, Department of Psychiatry, United States.
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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11
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Yager JY. Glucose and Perinatal Brain Injury—Questions and Controversies. Neurology 2019. [DOI: 10.1016/b978-0-323-54392-7.00009-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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13
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Dong F, Liu Y, Zhang Z, Guo R, Ma L, Qu X, Yu H, Fan H, Yao R. Postnatal alteration of monocarboxylate transporter 1 expression in the rat corpus callosum. Physiol Res 2017; 66:345-355. [PMID: 27982679 DOI: 10.33549/physiolres.933365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
In the central nervous system (CNS), monocarboxylate transporter 1 (MCT1) is expressed in astrocytes and endothelial cells but also in oligodendroglia. Oligodendroglia support neurons and axons through lactate transportation by MCT1. Limited information is available on the MCT1 expression changes in candidate cells in the developing rat brain, especially in corpus callosum which is the most vulnerable area in demyelinating diseases. In the present study, we investigated the expression pattern of MCT1 during postnatal development in the rat corpus callosum using immunofluorescene staining, Western blotting analysis and RT-PCR. We reported that MCT1 gene and protein were consistently expressed in the rat corpus callosum from birth to adult. MCT1/CNPase and MCT1/GFAP immunofluorescence staining demonstrated that most of MCT1 positive cells were co-labeled with cyclic nucleotide 3´ phosphodiesterase (CNPase) in rat corpus callosum from P7 to adult, whereas MCT1(+)/GFAP(+) cells preserve the dominate position before P7. Moreover, there were significant associations between the expression of MCT1 protein and the expression of myelin basic protein (MBP) (correlation coefficient: r=0.962, P=0.009) from P7 to adult. Similarly, the MCT1 mRNA expression was also significantly associated with MBP mRNA expression (r=0.976, P=0.005). Our results are proposing that in the developing brain white matter, MCT1 is predominately expressed in oligodendrocyte though it mainly expressed in astrocyte in early postnatal, which indicate that MCT1 may involve in the oligodendrocyte development and myelination.
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Affiliation(s)
- Fuxing Dong
- Department of Neurobiology, Xuzhou Medical University, Xuzhou, Jiangsu, People's Republic of China.
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Almenrader N, Colucci P, De Castro V, Valeri D, Palmery M, Trezza V, Campolongo P. Effects of sevoflurane and clonidine on acid base status and long-term emotional and cognitive outcomes in spontaneously breathing rat pups. PLoS One 2017; 12:e0173969. [PMID: 28319126 PMCID: PMC5358762 DOI: 10.1371/journal.pone.0173969] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 03/01/2017] [Indexed: 12/20/2022] Open
Abstract
Background Numerous experiments in rodents suggest a causative link between exposure to general anaesthetics during brain growth spurt and poor long-lasting neurological outcomes. Many of these studies have been questioned with regard of their translational value, mainly because of extremely long anaesthesia exposure. Therefore, the aim of the present study was to assess the impact of a short sevoflurane anaesthesia, alone or combined with clonidine treatment, on respiratory function in spontaneously breathing rat pups and overall effects on long-lasting emotional and cognitive functions. Methods At postnatal day (PND) 7, male Sprague Dawley rat pups were randomized into four groups and exposed to sevoflurane for one hour, to a single dose of intraperitoneal clonidine or to a combination of both and compared to a control group. Blood gas analysis was performed at the end of sevoflurane anaesthesia and after 60 minutes from clonidine or saline injection. Emotional and cognitive outcomes were evaluated in different group of animals at infancy (PND12), adolescence (PND 30–40) and adulthood (PND 70–90). Results Rat pups exposed to either sevoflurane or to a combination of sevoflurane and clonidine developed severe hypercapnic acidosis, but maintained normal arterial oxygenation. Emotional and cognitive outcomes were not found altered in any of the behavioural task used either at infancy, adolescence or adulthood. Conclusions Sixty minutes of sevoflurane anaesthesia in newborn rats, either alone or combined with clonidine, caused severe hypercapnic acidosis in spontaneously breathing rat pups, but was devoid of long-term behavioural dysfunctions in the present setting.
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Affiliation(s)
- Nicole Almenrader
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Department of Anaesthesia and Intensive Care, Policlinico Umberto I, Rome, Italy
| | - Paola Colucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Valentina De Castro
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Daniela Valeri
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Maura Palmery
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Viviana Trezza
- Department of Science, Section of Biomedical Sciences and Technologies, University “Roma Tre”, Rome, Italy
| | - Patrizia Campolongo
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- * E-mail:
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Weiler A, Volkenhoff A, Hertenstein H, Schirmeier S. Metabolite transport across the mammalian and insect brain diffusion barriers. Neurobiol Dis 2017; 107:15-31. [PMID: 28237316 DOI: 10.1016/j.nbd.2017.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 01/02/2017] [Accepted: 02/20/2017] [Indexed: 12/31/2022] Open
Abstract
The nervous system in higher vertebrates is separated from the circulation by a layer of specialized endothelial cells. It protects the sensitive neurons from harmful blood-derived substances, high and fluctuating ion concentrations, xenobiotics or even pathogens. To this end, the brain endothelial cells and their interlinking tight junctions build an efficient diffusion barrier. A structurally analogous diffusion barrier exists in insects, where glial cell layers separate the hemolymph from the neural cells. Both types of diffusion barriers, of course, also prevent influx of metabolites from the circulation. Because neuronal function consumes vast amounts of energy and necessitates influx of diverse substrates and metabolites, tightly regulated transport systems must ensure a constant metabolite supply. Here, we review the current knowledge about transport systems that carry key metabolites, amino acids, lipids and carbohydrates into the vertebrate and Drosophila brain and how this transport is regulated. Blood-brain and hemolymph-brain transport functions are conserved and we can thus use a simple, genetically accessible model system to learn more about features and dynamics of metabolite transport into the brain.
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Affiliation(s)
- Astrid Weiler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Helen Hertenstein
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany.
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Dienel GA. Lack of appropriate stoichiometry: Strong evidence against an energetically important astrocyte-neuron lactate shuttle in brain. J Neurosci Res 2017; 95:2103-2125. [PMID: 28151548 DOI: 10.1002/jnr.24015] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 11/28/2016] [Accepted: 12/16/2016] [Indexed: 12/22/2022]
Abstract
Glutamate-stimulated aerobic glycolysis in astrocytes coupled with lactate shuttling to neurons where it can be oxidized was proposed as a mechanism to couple excitatory neuronal activity with glucose utilization (CMRglc ) during brain activation. From the outset, this model was not viable because it did not fulfill critical stoichiometric requirements: (i) Calculated glycolytic rates and measured lactate release rates were discordant in cultured astrocytes. (ii) Lactate oxidation requires oxygen consumption, but the oxygen-glucose index (OGI, calculated as CMRO2 /CMRglc ) fell during activation in human brain, and the small rise in CMRO2 could not fully support oxidation of lactate produced by disproportionate increases in CMRglc . (iii) Labeled products of glucose metabolism are not retained in activated rat brain, indicating rapid release of a highly labeled, diffusible metabolite identified as lactate, thereby explaining the CMRglc -CMRO2 mismatch. Additional independent lines of evidence against lactate shuttling include the following: astrocytic oxidation of glutamate after its uptake can help "pay" for its uptake without stimulating glycolysis; blockade of glutamate receptors during activation in vivo prevents upregulation of metabolism and lactate release without impairing glutamate uptake; blockade of β-adrenergic receptors prevents the fall in OGI in activated human and rat brain while allowing glutamate uptake; and neurons upregulate glucose utilization in vivo and in vitro under many stimulatory conditions. Studies in immature cultured cells are not appropriate models for lactate shuttling in adult brain because of their incomplete development of metabolic capability and astrocyte-neuron interactions. Astrocyte-neuron lactate shuttling does not make large, metabolically significant contributions to energetics of brain activation. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, and Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico
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Elizondo-Vega R, García-Robles MA. Molecular Characteristics, Regulation, and Function of Monocarboxylate Transporters. ADVANCES IN NEUROBIOLOGY 2017; 16:255-267. [PMID: 28828614 DOI: 10.1007/978-3-319-55769-4_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lactate transporters play an important role in the glutamate recycling. Here their kinetics and tissue distribution with emphasis on the brain are addressed. Recent evidence shows their participation in important brain functions that involve intercellular communication, such as hypothalamic glucose sensing. Furthermore, we describe the regulation of their expression and some animal models that have allowed clarification of their functions.
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18
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Glucose and Intermediary Metabolism and Astrocyte–Neuron Interactions Following Neonatal Hypoxia–Ischemia in Rat. Neurochem Res 2016; 42:115-132. [DOI: 10.1007/s11064-016-2149-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 12/09/2016] [Accepted: 12/10/2016] [Indexed: 11/27/2022]
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Inhibition of hypothalamic MCT1 expression increases food intake and alters orexigenic and anorexigenic neuropeptide expression. Sci Rep 2016; 6:33606. [PMID: 27677351 PMCID: PMC5039692 DOI: 10.1038/srep33606] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/30/2016] [Indexed: 01/24/2023] Open
Abstract
Hypothalamic glucosensing, which involves the detection of glucose concentration changes by brain cells and subsequent release of orexigenic or anorexigenic neuropeptides, is a crucial process that regulates feeding behavior. Arcuate nucleus (AN) neurons are classically thought to be responsible for hypothalamic glucosensing through a direct sensing mechanism; however, recent data has shown a metabolic interaction between tanycytes and AN neurons through lactate that may also be contributing to this process. Monocarboxylate transporter 1 (MCT1) is the main isoform expressed by tanycytes, which could facilitate lactate release to hypothalamic AN neurons. We hypothesize that MCT1 inhibition could alter the metabolic coupling between tanycytes and AN neurons, altering feeding behavior. To test this, we inhibited MCT1 expression using adenovirus-mediated transfection of a shRNA into the third ventricle, transducing ependymal wall cells and tanycytes. Neuropeptide expression and feeding behavior were measured in MCT1-inhibited animals after intracerebroventricular glucose administration following a fasting period. Results showed a loss in glucose regulation of orexigenic neuropeptides and an abnormal expression of anorexigenic neuropeptides in response to fasting. This was accompanied by an increase in food intake and in body weight gain. Taken together, these results indicate that MCT1 expression in tanycytes plays a role in feeding behavior regulation.
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Zhang M, Ma Z, Qin H, Yao Z. Monocarboxylate Transporter 1 in the Medial Prefrontal Cortex Developmentally Expresses in Oligodendrocytes and Associates with Neuronal Amounts. Mol Neurobiol 2016; 54:2315-2326. [DOI: 10.1007/s12035-016-9820-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 02/29/2016] [Indexed: 01/10/2023]
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McKenna MC, Scafidi S, Robertson CL. Metabolic Alterations in Developing Brain After Injury: Knowns and Unknowns. Neurochem Res 2015; 40:2527-43. [PMID: 26148530 PMCID: PMC4961252 DOI: 10.1007/s11064-015-1600-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/10/2015] [Accepted: 05/02/2015] [Indexed: 12/21/2022]
Abstract
Brain development is a highly orchestrated complex process. The developing brain utilizes many substrates including glucose, ketone bodies, lactate, fatty acids and amino acids for energy, cell division and the biosynthesis of nucleotides, proteins and lipids. Metabolism is crucial to provide energy for all cellular processes required for brain development and function including ATP formation, synaptogenesis, synthesis, release and uptake of neurotransmitters, maintaining ionic gradients and redox status, and myelination. The rapidly growing population of infants and children with neurodevelopmental and cognitive impairments and life-long disability resulting from developmental brain injury is a significant public health concern. Brain injury in infants and children can have devastating effects because the injury is superimposed on the high metabolic demands of the developing brain. Acute injury in the pediatric brain can derail, halt or lead to dysregulation of the complex and highly regulated normal developmental processes. This paper provides a brief review of metabolism in developing brain and alterations found clinically and in animal models of developmental brain injury. The metabolic changes observed in three major categories of injury that can result in life-long cognitive and neurological disabilities, including neonatal hypoxia-ischemia, pediatric traumatic brain injury, and brain injury secondary to prematurity are reviewed.
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, 655 W. Baltimore St., Room 13-019, Baltimore, MD, 21201, USA.
| | - Susanna Scafidi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Courtney L Robertson
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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22
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Xu S, Waddell J, Zhu W, Shi D, Marshall AD, McKenna MC, Gullapalli RP. In vivo longitudinal proton magnetic resonance spectroscopy on neonatal hypoxic-ischemic rat brain injury: Neuroprotective effects of acetyl-L-carnitine. Magn Reson Med 2015; 74:1530-42. [PMID: 25461739 PMCID: PMC4452442 DOI: 10.1002/mrm.25537] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/04/2014] [Accepted: 10/30/2014] [Indexed: 12/14/2022]
Abstract
PURPOSE This study evaluated the longitudinal metabolic alterations after neonatal hypoxia-ischemia (HI) in rats and tested the neuroprotective effect of acetyl-L-carnitine (ALCAR) using in vivo proton short-TE Point-RESolved Spectroscopy method. METHODS Rice-Vannucci model was used on 7-day-old Sprague-Dawley rats. Data were acquired from contralateral and ipsilateral cortex and hippocampus, respectively at 4 time points (24-h, 72-h, 7-days, 28-days) post-HI. The effect of subcutaneous administration of ALCAR (100 mg/kg) immediately after HI, at 4-h, 24-h, and 48-h post-HI was determined. RESULTS Significant reductions in glutathione (P < 0.005), myo-inositol (P < 0.002), taurine (P < 0.001), and total creatine (P < 0.005) were observed at 24-h postinjury compared with the control group in the ipsilateral hippocampus of the HI rat pups. ALCAR-treated-HI rats had lower levels of lactate and maintained total creatine at 24-h and had smaller lesion size compared with the HI only rats. CONCLUSION Severe oxidative, osmotic stress, impaired phosphorylation, and a preference for anaerobic glycolysis were found in the ipsilateral hippocampus in the HI pups at 24-h postinjury. ALCAR appeared to have a neuroprotective effect if administered early after HI by serving as an energy substrate and promote oxidative cerebral energy producing and minimize anaerobic glycolysis.
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Affiliation(s)
- Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jaylyn Waddell
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Da Shi
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Andrew D Marshall
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rao P Gullapalli
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Core for Translational Research in Imaging @ Maryland, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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23
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Berger HR, Morken TS, Vettukattil R, Brubakk AM, Sonnewald U, Widerøe M. No improvement of neuronal metabolism in the reperfusion phase with melatonin treatment after hypoxic-ischemic brain injury in the neonatal rat. J Neurochem 2015; 136:339-50. [PMID: 26526584 DOI: 10.1111/jnc.13420] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 01/13/2023]
Abstract
Mitochondrial impairment is a key feature underlying neonatal hypoxic-ischemic (HI) brain injury and melatonin is potentially neuroprotective through its effects on mitochondria. In this study, we have used (1) H and (13) C NMR spectroscopy after injection of [1-(13) C]glucose and [1,2-(13) C]acetate to examine neuronal and astrocytic metabolism in the early reperfusion phase after unilateral HI brain injury in 7-day-old rat pups, exploring the effects of HI on mitochondrial function and the potential protective effects of melatonin on brain metabolism. One hour after hypoxia-ischemia, astrocytic metabolism was recovered and glycolysis was normalized, whereas mitochondrial metabolism in neurons was clearly impaired. Pyruvate carboxylation was also lower in both hemispheres after HI. The transfer of glutamate from neurons to astrocytes was higher whereas the transfer of glutamine from astrocytes to neurons was lower 1 h after HI in the contralateral hemisphere. Neuronal metabolism was equally affected in pups treated with melatonin (10 mg/kg) immediately after HI as in vehicle treated pups indicating that the given dose of melatonin was not capable of protecting the neuronal mitochondria in this early phase after HI brain injury. However, any beneficial effects of melatonin might have been masked by modulatory effects of the solvent dimethyl sulfoxide on cerebral metabolism. Neuronal and astrocytic metabolism was examined by (13) C and (1) H NMR spectroscopy in the early reperfusion phase after unilateral hypoxic-ischemic brain injury and melatonin treatment in neonatal rats. One hour after hypoxia-ischemia astrocytic mitochondrial metabolism had recovered and glycolysis was normalized, whereas mitochondrial metabolism in neurons was impaired. Melatonin treatment did not show a protective effect on neuronal metabolism.
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Affiliation(s)
- Hester R Berger
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Tora Sund Morken
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Ophthalmology, Trondheim University Hospital, Trondheim, Norway
| | - Riyas Vettukattil
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ann-Mari Brubakk
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ursula Sonnewald
- Department of Neuroscience, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marius Widerøe
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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McKenna MC, Scafidi S, Robertson CL. Metabolic Alterations in Developing Brain After Injury: Knowns and Unknowns. Neurochem Res 2015. [PMID: 26148530 DOI: 10.1007/s11064‐015‐1600‐7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Brain development is a highly orchestrated complex process. The developing brain utilizes many substrates including glucose, ketone bodies, lactate, fatty acids and amino acids for energy, cell division and the biosynthesis of nucleotides, proteins and lipids. Metabolism is crucial to provide energy for all cellular processes required for brain development and function including ATP formation, synaptogenesis, synthesis, release and uptake of neurotransmitters, maintaining ionic gradients and redox status, and myelination. The rapidly growing population of infants and children with neurodevelopmental and cognitive impairments and life-long disability resulting from developmental brain injury is a significant public health concern. Brain injury in infants and children can have devastating effects because the injury is superimposed on the high metabolic demands of the developing brain. Acute injury in the pediatric brain can derail, halt or lead to dysregulation of the complex and highly regulated normal developmental processes. This paper provides a brief review of metabolism in developing brain and alterations found clinically and in animal models of developmental brain injury. The metabolic changes observed in three major categories of injury that can result in life-long cognitive and neurological disabilities, including neonatal hypoxia-ischemia, pediatric traumatic brain injury, and brain injury secondary to prematurity are reviewed.
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, 655 W. Baltimore St., Room 13-019, Baltimore, MD, 21201, USA.
| | - Susanna Scafidi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Courtney L Robertson
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Transcriptional analysis of glial cell differentiation in the postnatal murine spinal cord. Int J Dev Neurosci 2015; 42:24-36. [PMID: 25702526 DOI: 10.1016/j.ijdevneu.2015.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/28/2015] [Accepted: 02/14/2015] [Indexed: 11/20/2022] Open
Abstract
Postnatal murine spinal cord represents a good model system to study mammalian central nervous system myelination in vivo as a basis for further studies in demyelinating diseases. Transcriptional changes were analyzed in SJL/J mice on postnatal day 0, 14, 49 and 231 (P0, P14, P49, P231) employing Affymetrix GeneChip Mouse Genome 430 2.0 Arrays. Additionally, marker gene signatures for astrocyte and oligodendrocyte lineage-stages were defined to study their gene expression in more detail. In addition, immunohistochemistry was used to quantify the abundance of commonly used glial cell markers. 6092 differentially regulated genes (DEGs) were identified. The up-regulated DEGs at P14, P49 and P231 compared to P0 exhibited significantly enriched associations to gene ontology terms such as myelination and lipid metabolic transport and down-regulated DEGs to neurogenesis and axonogenesis. Expression values of marker gene signatures for neural stem cells, oligodendrocyte precursor cells, and developing astrocytes were constantly decreasing, whereas myelinating oligodendrocyte and mature astrocyte markers showed a steady increase. Molecular findings were substantiated by immunohistochemical observations. The transcriptional changes observed are an important reference for future analysis of degenerative and inflammatory conditions in the spinal cord.
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Brekke E, Morken TS, Sonnewald U. Glucose metabolism and astrocyte-neuron interactions in the neonatal brain. Neurochem Int 2015; 82:33-41. [PMID: 25684072 DOI: 10.1016/j.neuint.2015.02.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 02/07/2015] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
Abstract
Glucose is essentially the sole fuel for the adult brain and the mapping of its metabolism has been extensive in the adult but not in the neonatal brain, which is believed to rely mainly on ketone bodies for energy supply. However, glucose is absolutely indispensable for normal development and recent studies have shed light on glycolysis, the pentose phosphate pathway and metabolic interactions between astrocytes and neurons in the 7-day-old rat brain. Appropriately (13)C labeled glucose was used to distinguish between glycolysis and the pentose phosphate pathway during development. Experiments using (13)C labeled acetate provided insight into the GABA-glutamate-glutamine cycle between astrocytes and neurons. It could be shown that in the neonatal brain the part of this cycle that transfers glutamine from astrocytes to neurons is operating efficiently while, in contrast, little glutamate is shuttled from neurons to astrocytes. This lack of glutamate for glutamine synthesis is compensated for by anaplerosis via increased pyruvate carboxylation relative to that in the adult brain. Furthermore, compared to adults, relatively more glucose is prioritized to the pentose phosphate pathway than glycolysis and pyruvate dehydrogenase activity. The reported developmental differences in glucose metabolism and neurotransmitter synthesis may determine the ability of the brain at various ages to resist excitotoxic insults such as hypoxia-ischemia.
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Affiliation(s)
- Eva Brekke
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim N-7489, Norway; Department of Pediatrics, Division of Pediatrics, Obstetrics and Women's Health, Nordland Hospital Trust, Bodo, Norway
| | - Tora Sund Morken
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology (NTNU), Trondheim N-7489, Norway; Department of Ophthalmology, St. Olav's Hospital HF, Trondheim, Norway
| | - Ursula Sonnewald
- Department of Neuroscience, Norwegian University of Science and Technology, Trondheim N-7489, Norway.
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28
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Kumar V, Nag TC, Sharma U, Mewar S, Jagannathan NR, Wadhwa S. High resolution 1H NMR-based metabonomic study of the auditory cortex analogue of developing chick (Gallus gallus domesticus) following prenatal chronic loud music and noise exposure. Neurochem Int 2014; 76:99-108. [DOI: 10.1016/j.neuint.2014.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/16/2014] [Accepted: 07/04/2014] [Indexed: 02/07/2023]
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29
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Morken TS, Brekke E, Håberg A, Widerøe M, Brubakk AM, Sonnewald U. Altered Astrocyte–Neuronal Interactions After Hypoxia-Ischemia in the Neonatal Brain in Female and Male Rats. Stroke 2014; 45:2777-85. [DOI: 10.1161/strokeaha.114.005341] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tora Sund Morken
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
| | - Eva Brekke
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
| | - Asta Håberg
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
| | - Marius Widerøe
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
| | - Ann-Mari Brubakk
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
| | - Ursula Sonnewald
- From the Department of Laboratory Medicine, Children’s and Women’s Health (T.S.M., A.-M.B.), Department of Neuroscience (E.B., A.H., U.S.), and Departments of Circulation and Medical Imaging (M.W.), Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Departments of Physical Medicine and Rehabilitation, St Olavs Hospital HF, Trondheim, Norway (T.S.M.); and Department of Medicine, Nordland Hospital Trust, Bodo, Norway (E.B.)
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The pentose phosphate pathway and pyruvate carboxylation after neonatal hypoxic-ischemic brain injury. J Cereb Blood Flow Metab 2014; 34:724-34. [PMID: 24496178 PMCID: PMC3982102 DOI: 10.1038/jcbfm.2014.8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 01/04/2014] [Accepted: 01/06/2014] [Indexed: 11/09/2022]
Abstract
The neonatal brain is vulnerable to oxidative stress, and the pentose phosphate pathway (PPP) may be of particular importance to limit the injury. Furthermore, in the neonatal brain, neurons depend on de novo synthesis of neurotransmitters via pyruvate carboxylase (PC) in astrocytes to increase neurotransmitter pools. In the adult brain, PPP activity increases in response to various injuries while pyruvate carboxylation is reduced after ischemia. However, little is known about the response of these pathways after neonatal hypoxia-ischemia (HI). To this end, 7-day-old rats were subjected to unilateral carotid artery ligation followed by hypoxia. Animals were injected with [1,2-(13)C]glucose during the recovery phase and extracts of cerebral hemispheres ipsi- and contralateral to the operation were analyzed using (1)H- and (13)C-NMR (nuclear magnetic resonance) spectroscopy and high-performance liquid chromatography (HPLC). After HI, glucose levels were increased and there was evidence of mitochondrial hypometabolism in both hemispheres. Moreover, metabolism via PPP was reduced bilaterally. Ipsilateral glucose metabolism via PC was reduced, but PC activity was relatively preserved compared with glucose metabolism via pyruvate dehydrogenase. The observed reduction in PPP activity after HI may contribute to the increased susceptibility of the neonatal brain to oxidative stress.
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Neuron-astrocyte interactions, pyruvate carboxylation and the pentose phosphate pathway in the neonatal rat brain. Neurochem Res 2013; 39:556-69. [PMID: 23504293 DOI: 10.1007/s11064-013-1014-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/04/2013] [Accepted: 03/02/2013] [Indexed: 10/27/2022]
Abstract
Glucose and acetate metabolism and the synthesis of amino acid neurotransmitters, anaplerosis, glutamate-glutamine cycling and the pentose phosphate pathway (PPP) have been extensively investigated in the adult, but not the neonatal rat brain. To do this, 7 day postnatal (P7) rats were injected with [1-(13)C]glucose and [1,2-(13)C]acetate and sacrificed 5, 10, 15, 30 and 45 min later. Adult rats were injected and sacrificed after 15 min. To analyse pyruvate carboxylation and PPP activity during development, P7 rats received [1,2-(13)C]glucose and were sacrificed 30 min later. Brain extracts were analysed using (1)H- and (13)C-NMR spectroscopy. Numerous differences in metabolism were found between the neonatal and adult brain. The neonatal brain contained lower levels of glutamate, aspartate and N-acetylaspartate but similar levels of GABA and glutamine per mg tissue. Metabolism of [1-(13)C]glucose at the acetyl CoA stage was reduced much more than that of [1,2-(13)C]acetate. The transfer of glutamate from neurons to astrocytes was much lower while transfer of glutamine from astrocytes to glutamatergic neurons was relatively higher. However, transport of glutamine from astrocytes to GABAergic neurons was lower. Using [1,2-(13)C]glucose it could be shown that despite much lower pyruvate carboxylation, relatively more pyruvate from glycolysis was directed towards anaplerosis than pyruvate dehydrogenation in astrocytes. Moreover, the ratio of PPP/glucose-metabolism was higher. These findings indicate that only the part of the glutamate-glutamine cycle that transfers glutamine from astrocytes to neurons is operating in the neonatal brain and that compared to adults, relatively more glucose is prioritised to PPP and pyruvate carboxylation. Our results may have implications for the capacity to protect the neonatal brain against excitotoxicity and oxidative stress.
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Álvarez Z, Mateos-Timoneda MA, Hyroššová P, Castaño O, Planell JA, Perales JC, Engel E, Alcántara S. The effect of the composition of PLA films and lactate release on glial and neuronal maturation and the maintenance of the neuronal progenitor niche. Biomaterials 2013; 34:2221-33. [DOI: 10.1016/j.biomaterials.2012.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/09/2012] [Indexed: 12/12/2022]
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Stridh MH, Alt MD, Wittmann S, Heidtmann H, Aggarwal M, Riederer B, Seidler U, Wennemuth G, McKenna R, Deitmer JW, Becker HM. Lactate flux in astrocytes is enhanced by a non-catalytic action of carbonic anhydrase II. J Physiol 2012; 590:2333-51. [PMID: 22451434 DOI: 10.1113/jphysiol.2011.220152] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Rapid exchange of metabolites between different cell types is crucial for energy homeostasis of the brain. Besides glucose, lactate is a major metabolite in the brain and is primarily produced in astrocytes. In the present study, we report that carbonic anhydrase 2 (CAII) enhances both influx and efflux of lactate in mouse cerebellar astrocytes. The augmentation of lactate transport is independent of the enzyme's catalytic activity, but requires direct binding of CAII to the C-terminal of the monocarboxylate transporter MCT1, one of the major lactate/proton cotransporters in astrocytes and most tissues. By employing its intramolecular proton shuttle, CAII, bound to MCT1, can act as a ‘proton collecting antenna' for the transporter, suppressing the formation of proton microdomains at the transporter-pore and thereby enhancing lactate flux. By this mechanism CAII could enhance transfer of lactate between astrocytes and neurons and thus provide the neurons with an increased supply of energy substrate.
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Affiliation(s)
- Malin H Stridh
- Division of General Zoology, Department of Biology, University of Kaiserslautern, PO Box 3049, D-67653 Kaiserslautern, Germany
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Takebe K, Takahashi-Iwanaga H, Iwanaga T. Intensified expressions of a monocarboxylate transporter in consistently renewing tissues of the mouse. ACTA ACUST UNITED AC 2012; 32:293-301. [PMID: 21878737 DOI: 10.2220/biomedres.32.293] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Monocarboxylates-lactate and ketone bodies-can compensate for glucose as energy sources under certain physical conditions. To identify the main energy source used in self-renewing tissues, expression profiles of monocarboxylate transporters (MCTs) were mainly investigated immunohistochemically in the gastrointestinal tract, skin, and bone marrow of mice, with reference to glucose transporters. In the small intestine, MCT1-immunoreactive epithelial cells accumulated in crypts with a selective immunolabeling along the basolateral membrane of cells. BrdU-labeled dividing cells were included in the cryptal MCT1-immunoreactive foci. The skin displayed an intense and extensive immunoreactivity for MCT1 in the hair bulge, which gives rise to the epidermis, hair, and sebaceous gland. The stratified squamous epithelium in the esophagus contained MCT1-immunoreactive cells in the basal layer but frequently lacked GLUT1-immunoreactive cells. The bone marrow was largely immunoreactive for MCT1 but not for GLUT1, suggesting the active production and utilization of monocarboxylates for hematopoiesis under hypoxic conditions. These findings support the idea that monocarboxylates are favorite energy sources in self-renewing tissues.
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Affiliation(s)
- Kumiko Takebe
- Laboratory of Histology and Cytology, Graduate School of Medicine, Hokkaido University, Kita 15-Nishi 7, Sapporo 060-8638, Japan
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Abstract
Cerebral energy metabolism is a highly compartmentalized and complex process in which transcellular trafficking of metabolites plays a pivotal role. Over the past decade, a role for lactate in fueling the energetic requirements of neurons has emerged. Furthermore, a neuroprotective effect of lactate during hypoglycemia or cerebral ischemia has been reported. The majority of the current evidence concerning lactate metabolism at the cellular level is based on in vitro data; only a few recent in vivo results have demonstrated that the brain preferentially utilizes lactate over glucose. Using voltage-sensitive dye (VSD) imaging, beta-probe measurements of radiotracer kinetics, and brain activation by sensory stimulation in the anesthetized rat, we investigated several aspects of cerebral lactate metabolism. The present study is the first in vivo demonstration of the maintenance of neuronal activity in the presence of lactate as the primary energy source. The loss of the voltage-sensitive dye signal found during severe insulin-induced hypoglycemia is completely prevented by lactate infusion. Thus, lactate has a direct neuroprotective effect. Furthermore, we demonstrate that the brain readily oxidizes lactate in an activity-dependent manner. The washout of 1-[(11)C]L-lactate, reflecting cerebral lactate oxidation, was observed to increase during brain activation from 0.077 ± 0.009 to 0.105 ± 0.007 min(-1). Finally, our data confirm that the brain prefers lactate over glucose as an energy substrate when both substrates are available. Using [(18)F]fluorodeoxyglucose (FDG) to measure the local cerebral metabolic rate of glucose, we demonstrated a lactate concentration-dependent reduction of cerebral glucose utilization during experimentally increased plasma lactate levels.
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Abstract
In the gray matter of the brain, astrocytes have been suggested to export lactate (derived from glucose or glycogen) to neurons to power their mitochondria. In the white matter, lactate can support axon function in conditions of energy deprivation, but it is not known whether lactate acts by preserving energy levels in axons or in oligodendrocytes, the myelinating processes of which are damaged rapidly in low energy conditions. Studies of cultured cells suggest that oligodendrocytes are the cell type in the brain that consumes lactate at the highest rate, in part to produce membrane lipids presumably for myelin. Here, we use pH imaging to show that oligodendrocytes in the white matter of the rat cerebellum and corpus callosum take up lactate via monocarboxylate transporters (MCTs), which we identify as MCT1 by confocal immunofluorescence and electron microscopy. Using cultured slices of developing cerebral cortex from mice in which oligodendrocyte lineage cells express GFP (green fluorescent protein) under the control of the Sox10 promoter, we show that a low glucose concentration reduces the number of oligodendrocyte lineage cells and myelination. Myelination is rescued when exogenous l-lactate is supplied. Thus, lactate can support oligodendrocyte development and myelination. In CNS diseases involving energy deprivation at times of myelination or remyelination, such as periventricular leukomalacia leading to cerebral palsy, stroke, and secondary ischemia after spinal cord injury, lactate transporters in oligodendrocytes may play an important role in minimizing the inhibition of myelination that occurs.
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Mukhtarov M, Ivanov A, Zilberter Y, Bregestovski P. Inhibition of spontaneous network activity in neonatal hippocampal slices by energy substrates is not correlated with intracellular acidification. J Neurochem 2011; 116:316-21. [PMID: 21083663 DOI: 10.1111/j.1471-4159.2010.07111.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several energy substrates complementary to glucose, including lactate, pyruvate and β-hydroxybutyrate, serve as a fuel for neurons. It was reported recently that these substrates can substantially modulate cortical excitability in neonatal slices. However, complementary energy substrates (CES) can also induce an intracellular acidification when added exogenously. Therefore, action of CES on the neuronal properties governing excitability in neonatal brain slices may be underlain by a change in the cell energy status or by intracellular acidification, or both. Here, we attempt to elucidate these possibilities in neonatal hippocampus by recording neuronal population activity and monitoring intracellular pH. We show that a spontaneous network activity pattern, giant depolarizing potentials (GDPs), characteristic for the neonatal hippocampal slices exposed to artificial cerebrospinal fluid, is strongly inhibited by CES and this effect is unlikely to be caused by a subtle intracellular acidification induced by these compounds. Indeed, a much stronger intracellular acidification in the HCO(3) -free solution inhibited neither the GDP frequency nor the GDP amplitude. Therefore, modulation of neuronal energy homeostasis is the most likely factor underlying the effect of lactate, pyruvate and β-hydroxybutyrate on network excitability in neonatal brain slices.
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Affiliation(s)
- Marat Mukhtarov
- INSERM-U901, Université de la Méditerranée, Marseille, France
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Rho JM. Another Look at Early GABAergic Neurotransmission: Maybe It's Not So Exciting After All! Epilepsy Curr 2010; 10:128-30. [PMID: 20944825 DOI: 10.1111/j.1535-7511.2010.01378.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
GABA Action in Immature Neocortical Neurons Directly Depends on the Availability of Ketone Bodies. Rheims S, Holmgren CD, Chazal G, Mulder J, Harkany T, Zilberter T, Zilberter Y. J Neurochem 2009;110(4):1330–1338. In the early postnatal period, energy metabolism in the suckling rodent brain relies to a large extent on metabolic pathways alternate to glucose such as the utilization of ketone bodies (KBs). However, how KBs affect neuronal excitability is not known. Using recordings of single NMDA and GABA-activated channels in neocortical pyramidal cells we studied the effects of KBs on the resting membrane potential ( Em) and reversal potential of GABA-induced anionic currents ( EGABA), respectively. We show that during postnatal development (P3–P19) if neocortical brain slices are adequately supplied with KBs, Em and EGABA are both maintained at negative levels of about −83 and −80 mV, respectively. Conversely, a KB deficiency causes a significant depolarization of both Em (>5 mV) and EGABA (>15 mV). The KB-mediated shift in EGABA is largely determined by the interaction of the NKCC1 cotransporter and Cl-/HCO3 transporter(s). Therefore, by inducing a hyperpolarizing shift in Em and modulating GABA signaling mode, KBs can efficiently control the excitability of neonatal cortical neurons. Energy Substrate Availability as a Determinant of Neuronal Resting Potential, GABA Signaling and Spontaneous Network Activity in the Neonatal Cortex In Vitro. Holmgren CD, Mukhtarov M, Malkov AE, Popova IY, Bregestovski P, Zilberter Y. J Neurochem 2010;112(4):900–912. While the ultimate dependence of brain function on its energy supply is evident, how basic neuronal parameters and network activity respond to energy metabolism deviations is unresolved. The resting membrane potential ( Em) and reversal potential of GABA-induced anionic currents ( EGABA) are among the most fundamental parameters controlling neuronal excitability. However, alterations of Em and EGABA under conditions of metabolic stress are not sufficiently documented, although it is well known that metabolic crisis may lead to neuronal hyper-excitability and aberrant neuronal network activities. In this work, we show that in slices, availability of energy substrates determines whether GABA signaling displays an inhibitory or excitatory mode, both in neonatal neocortex and hippocampus. We demonstrate that in the neonatal brain, Em and EGABA strongly depend on composition of the energy substrate pool. Complementing glucose with ketone bodies, pyruvate or lactate resulted in a significant hyperpolarization of both Em and EGABA, and induced a radical shift in the mode of GABAergic synaptic transmission towards network inhibition. Generation of giant depolarizing potentials, currently regarded as the hallmark of spontaneous neonatal network activity in vitro, was strongly inhibited both in neocortex and hippocampus in the energy substrate enriched solution. Based on these results we suggest the composition of the artificial cerebrospinal fluid, which bears a closer resemblance to the in vivo energy substrate pool. Our results suggest that energy deficits induce unfavorable changes in Em and EGABA, leading to neuronal hyperactivity that may initiate a cascade of pathological events.
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Holmgren CD, Mukhtarov M, Malkov AE, Popova IY, Bregestovski P, Zilberter Y. Energy substrate availability as a determinant of neuronal resting potential, GABA signaling and spontaneous network activity in the neonatal cortexin vitro. J Neurochem 2010; 112:900-12. [DOI: 10.1111/j.1471-4159.2009.06506.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Iwanaga T, Kuchiiwa T, Saito M. Histochemical demonstration of monocarboxylate transporters in mouse brown adipose tissue. ACTA ACUST UNITED AC 2009; 30:217-25. [PMID: 19729852 DOI: 10.2220/biomedres.30.217] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proton-coupled monocarboxylate transporters (MCTs) are essential for the transport of lactate, ketone bodies, and other monocarboxylates through the plasma membrane. The present immunohistochemical study aimed to examine the expression of MCTs in the brown adipose tissue (BAT) of mice. An intense immunoreactivity for MCT1 was found in the plasma membrane of brown adipose cells at light and electron microscopic levels but not in white adipose cells. The expression of MCT1 in BAT was confirmed by Western blot and in situ hybridization analyses. In fetuses (E17.5) and neonates, the MCT1 mRNA expression of BAT was abundant and appeared more intense than that in adult animals. These results, together with the intense expression of CD147 (a functional partner of MCTs) and acetyl-CoA carboxylase-2 (a component of fatty acid oxidation) in perinatal periods, suggest the involvement of MCT1 in the uptake of monocarboxylates from the circulation for thermogenesis rather than lipogenesis.
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Rheims S, Holmgren CD, Chazal G, Mulder J, Harkany T, Zilberter T, Zilberter Y. GABA action in immature neocortical neurons directly depends on the availability of ketone bodies. J Neurochem 2009; 110:1330-8. [DOI: 10.1111/j.1471-4159.2009.06230.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Mangia S, Simpson IA, Vannucci SJ, Carruthers A. The in vivo neuron-to-astrocyte lactate shuttle in human brain: evidence from modeling of measured lactate levels during visual stimulation. J Neurochem 2009; 109 Suppl 1:55-62. [PMID: 19393009 DOI: 10.1111/j.1471-4159.2009.06003.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Functional magnetic resonance spectroscopy (fMRS) allows the non-invasive measurement of metabolite concentrations in the human brain, including changes induced by variations in neurotransmission activity. However, the limited spatial and temporal resolution of fMRS does not allow specific measurements of metabolites in different cell types. Thus, the analysis of fMRS data in the context of compartmentalized metabolism requires the formulation and application of mathematical models. In the present study we utilized the mathematical model introduced by Simpson et al. (2007) to gain insights into compartmentalized metabolism in vivo from the fMRS data obtained in humans at ultra high magnetic field by Mangia et al. (2007a). This model simulates brain glucose and lactate levels in a theoretical cortical slice. Using experimentally determined concentrations and catalytic activities for the respective transporter proteins, we calculate inflow and export of glucose and lactate in endothelium, astrocytes, and neurons. We then vary neuronal and astrocytic glucose and lactate utilization capacities until close correspondence is observed between in vivo and simulated glucose and lactate levels. The results of the simulations indicate that, when literature values of glucose transport capacity are utilized, the fMRS data are consistent with export of lactate by neurons and import of lactate by astrocytes, a mechanism that can be referred to as a neuron-to-astrocyte lactate shuttle. A shuttle of lactate from astrocytes to neurons could be simulated, but this required the astrocytic glucose transport capacity to be increased by 12-fold, and required that neurons not respond to activation with increased glycolysis, two conditions that are not supported by current literature.
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Affiliation(s)
- Silvia Mangia
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA.
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MATSUYAMA S, OHKURA S, IWATA K, UENOYAMA Y, TSUKAMURA H, MAEDA KI, KIMURA K. Food Deprivation Induces Monocarboxylate Transporter 2 Expression in the Brainstem of Female Rat. J Reprod Dev 2009; 55:256-61. [DOI: 10.1262/jrd.20214] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Shuichi MATSUYAMA
- National Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization
| | - Satoshi OHKURA
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Kinuyo IWATA
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Yoshihisa UENOYAMA
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Hiroko TSUKAMURA
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Kei-ichiro MAEDA
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Koji KIMURA
- National Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization
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Takebe K, Nio-Kobayashi J, Takahashi-Iwanaga H, Iwanaga T. Histochemical demonstration of a monocarboxylate transporter in the mouse perineurium with special reference to GLUT1. Biomed Res 2008; 29:297-306. [DOI: 10.2220/biomedres.29.297] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yudkoff M, Daikhin Y, Melø TM, Nissim I, Sonnewald U, Nissim I. The ketogenic diet and brain metabolism of amino acids: relationship to the anticonvulsant effect. Annu Rev Nutr 2007; 27:415-30. [PMID: 17444813 PMCID: PMC4237068 DOI: 10.1146/annurev.nutr.27.061406.093722] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In many epileptic patients, anticonvulsant drugs either fail adequately to control seizures or they cause serious side effects. An important adjunct to pharmacologic therapy is the ketogenic diet, which often improves seizure control, even in patients who respond poorly to medications. The mechanisms that explain the therapeutic effect are incompletely understood. Evidence points to an effect on brain handling of amino acids, especially glutamic acid, the major excitatory neurotransmitter of the central nervous system. The diet may limit the availability of oxaloacetate to the aspartate aminotransferase reaction, an important route of brain glutamate handling. As a result, more glutamate becomes accessible to the glutamate decarboxylase reaction to yield gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter and an important antiseizure agent. In addition, the ketogenic diet appears to favor the synthesis of glutamine, an essential precursor to GABA. This occurs both because ketone body carbon is metabolized to glutamine and because in ketosis there is increased consumption of acetate, which astrocytes in the brain quickly convert to glutamine. The ketogenic diet also may facilitate mechanisms by which the brain exports to blood compounds such as glutamine and alanine, in the process favoring the removal of glutamate carbon and nitrogen.
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Affiliation(s)
- Marc Yudkoff
- Children's Hospital of Philadelphia and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
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Puchowicz MA, Xu K, Sun X, Ivy A, Emancipator D, LaManna JC. Diet-induced ketosis increases capillary density without altered blood flow in rat brain. Am J Physiol Endocrinol Metab 2007; 292:E1607-15. [PMID: 17284577 DOI: 10.1152/ajpendo.00512.2006] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is recognized that ketone bodies, such as R-beta-hydroxybutyrate (beta-HB) and acetoacetate, are energy sources for the brain. As with glucose metabolism, monocarboxylate uptake by the brain is dependent on the function and regulation of its own transporter system. We concurrently investigated ketone body influx, blood flow, and regulation of monocarboxylate transporter (MCT-1) and glucose transporter (GLUT-1) in diet-induced ketotic (KG) rat brain. Regional blood-to-brain beta-HB influx (micromol.g(-1).min(-1)) increased 40-fold with ketosis (4.8 +/- 1.8 plasmabeta-HB; mM) in all regions compared with the nonketotic groups (standard and no-fat diets); there were no changes in regional blood flow. Immunohistochemical staining revealed that GLUT-1 density (number/mm2) in the cortex was significantly elevated (40%) in the ketotic group compared with the standard and no-fat diet groups. MCT-1 was also markedly (3-fold) upregulated in the ketotic group compared with the standard diet group. In the standard diet group, 40% of the brain capillaries stained positive for MCT-1; this amount doubled with the ketotic diet. Western blot analysis of isolated microvessels from ketotic rat brain showed an eightfold increase in GLUT-1 and a threefold increase in MCT-1 compared with the standard diet group. These data suggest that diet-induced ketosis results in increased vascular density at the blood-brain barrier without changes in blood flow. The increase in extraction fraction and capillary density with increased plasma ketone bodies indicates a significant flux of substrates available for brain energy metabolism.
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Affiliation(s)
- Michelle A Puchowicz
- Department of Anatomy, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106-4938, USA.
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Tarasenko AS, Linetska MV, Storchak LG, Himmelreich NH. Effectiveness of extracellular lactate/pyruvate for sustaining synaptic vesicle proton gradient generation and vesicular accumulation of GABA. J Neurochem 2006; 99:787-96. [PMID: 16836653 DOI: 10.1111/j.1471-4159.2006.04109.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of extracellular monocarboxylates pyruvate and lactate on membrane potentials, acidification and neurotransmitter filling of synaptic vesicles were investigated in experiments with rat brain synaptosomes using [(3)H]GABA and fluorescent dyes, potential-sensitive rhodamine 6G and pH-sensitive acridine orange. In experiments investigating accumulation of acridine orange in synaptic vesicles within the synaptosomes, monocarboxylates, similarly to glucose, ensured generation of the vesicle proton gradient by available and recycled vesicles, and pyruvate demonstrated the highest efficacy. An increase in the level of proton gradient correlated with enhanced accumulation of [(3)H]GABA in synaptic vesicles and resulted in enlarged exocytosis and attenuated the transporter-mediated [(3)H]GABA release. Pyruvate added to glucose-contained medium caused more active binding of rhodamine 6G by synaptosomes that reflected mitochondrial membrane hyperpolarization, and this intensification of nerve terminal energy metabolism resulted in an increase in total ATP content by approximately 25%. Pyruvate also prolonged the state of metabolic competence of nerve terminal preparations, keeping the mitochondrial potential and synaptic vesicle proton gradient at steady levels over a long period of time. Thus, besides glucose, the extracellular monocarboxylates pyruvate and lactate can provide sufficient support of energy-dependent processes in isolated nerve terminals, allowing effective functioning of neurotransmitter release and reuptake systems.
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Affiliation(s)
- A S Tarasenko
- Department of Neurochemistry, Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
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Muller AP, Rotta LN, Kawano C, Leszczinski DN, Schweigert ID, Londero LG, Gravina FS, da Silveira CKB, de Souza CG, Battu CE, Gonçalves CA, de Souza DO, Perry MLS. Effect of 2-deoxy-D-glucose on aminoacids metabolism in rats' cerebral cortex slices. Neurochem Res 2006; 31:417-22. [PMID: 16733818 DOI: 10.1007/s11064-005-9031-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2005] [Indexed: 10/24/2022]
Abstract
We studied the effect of different concentrations of 2-deoxy-D-glucose on the L-[U-14C]leucine, L-[1-14C]leucine and [1-14C]glycine metabolism in slices of cerebral cortex of 10-day-old rats. 2-deoxy-D-glucose since 0.5 mM concentration has inhibited significantly the protein synthesis from L-[U-14C]leucine and from [1-14C]glycine in relation to the medium containing only Krebs Ringer bicarbonate. Potassium 8.0 mM in incubation medium did not stimulate the protein synthesis compared to the medium containing 2.7 mM, and at 50 mM diminishes more than 2.5 times the protein synthesis compared to the other concentration. Only at the concentration of 5.0 mM, 2-deoxy-D-glucose inhibited the CO2 production and lipid synthesis from L-[U-14C] leucine. This compound did not inhibit either CO2 production, or lipid synthesis from [1-14C]glycine. Lactate at 10 mM and glucose 5.0 mM did not revert the inhibitory effect of 2-deoxy-D-glucose on the protein synthesis from L-[U-14C]leucine. 2-deoxy-D-glucose at 2.0 mM did not show any effect either on CO2 production, or on lipid synthesis from L-[U-14C]lactate 10 mM and glucose 5.0 mM.
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Affiliation(s)
- Alexandre P Muller
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Melø TM, Nehlig A, Sonnewald U. Neuronal-glial interactions in rats fed a ketogenic diet. Neurochem Int 2006; 48:498-507. [PMID: 16542760 DOI: 10.1016/j.neuint.2005.12.037] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 12/19/2005] [Accepted: 12/22/2005] [Indexed: 11/16/2022]
Abstract
Glucose is the preferred energy substrate for the adult brain. However, during periods of fasting and consumption of a high fat, low carbohydrate (ketogenic) diet, ketone bodies become major brain fuels. The present study was conducted to investigate how the ketogenic diet influences neuronal-glial interactions in amino acid neurotransmitter metabolism. Rats were kept on a standard or ketogenic diet. After 21 days all animals received an injection of [1-(13)C]glucose plus [1,2-(13)C]acetate, the preferential substrates of neurons and astrocytes, respectively. Extracts from cerebral cortex and plasma were analyzed by (13)C and (1)H nuclear magnetic resonance spectroscopy and HPLC. Increased amounts of valine, leucine and isoleucine and a decreased amount of glutamate were found in the brains of rats receiving the ketogenic diet. Glycolysis was decreased in ketotic rats compared with controls, evidenced by the reduced amounts of [3-(13)C]alanine and [3-(13)C]lactate. Additionally, neuronal oxidative metabolism of [1-(13)C]glucose was decreased in ketotic rats compared with controls, since amounts of [4-(13)C]glutamate and [4-(13)C]glutamine were lower than those of controls. Although the amount of glutamate from [1-(13)C]glucose was decreased, this was not the case for GABA, indicating that relatively more [4-(13)C]glutamate is converted to GABA. Astrocytic metabolism was increased in response to ketosis, shown by increased amounts of [4,5-(13)C]glutamine, [4,5-(13)C]glutamate, [1,2-(13)C]GABA and [3,4-(13)C]-/[1,2-(13)C]aspartate derived from [1,2-(13)C]acetate. The pyruvate carboxylation over dehydrogenation ratio for glutamine was increased in the ketotic animals compared to controls, giving further indication of increased astrocytic metabolism. Interestingly, pyruvate recycling was higher in glutamine than in glutamate in both groups of animals. An increase in this pathway was detected in glutamate in response to ketosis. The decreased glycolysis and oxidative metabolism of glucose as well as the increased astrocytic metabolism, may reflect adaptation of the brain to ketone bodies as major source of fuel.
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Affiliation(s)
- Torun Margareta Melø
- Department of Neuroscience, Norwegian University of Science and Technology, NTNU, N-7489 Trondheim, Norway
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