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Wu J, Ren R, Chen T, Su LD, Tang T. Neuroimmune and neuroinflammation response for traumatic brain injury. Brain Res Bull 2024; 217:111066. [PMID: 39241894 DOI: 10.1016/j.brainresbull.2024.111066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2024] [Revised: 08/18/2024] [Accepted: 09/02/2024] [Indexed: 09/09/2024]
Abstract
Traumatic brain injury (TBI) is one of the major diseases leading to mortality and disability, causing a serious disease burden on individuals' ordinary lives as well as socioeconomics. In primary injury, neuroimmune and neuroinflammation are both responsible for the TBI. Besides, extensive and sustained injury induced by neuroimmune and neuroinflammation also prolongs the course and worsens prognosis of TBI. Therefore, this review aims to explore the role of neuroimmune, neuroinflammation and factors associated them in TBI as well as the therapies for TBI. Thus, we conducted by searching PubMed, Scopus, and Web of Science databases for articles published between 2010 and 2023. Keywords included "traumatic brain injury," "neuroimmune response," "neuroinflammation," "astrocytes," "microglia," and "NLRP3." Articles were selected based on relevance and quality of evidence. On this basis, we provide the cellular and molecular mechanisms of TBI-induced both neuroimmune and neuroinflammation response, as well as the different factors affecting them, are introduced based on physiology of TBI, which supply a clear overview in TBI-induced chain-reacting, for a better understanding of TBI and to offer more thoughts on the future therapies for TBI.
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Affiliation(s)
- Junyun Wu
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009, China
| | - Reng Ren
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009, China
| | - Tao Chen
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009, China
| | - Li-Da Su
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009, China.
| | - Tianchi Tang
- Department of Neurosurgery, Second Affiliated Hospital of Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009, China.
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2
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Denker N, Dringen R. Modulation of Pyruvate Export and Extracellular Pyruvate Concentration in Primary Astrocyte Cultures. Neurochem Res 2024; 49:1331-1346. [PMID: 38376749 PMCID: PMC10991036 DOI: 10.1007/s11064-024-04120-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/02/2024] [Accepted: 02/02/2024] [Indexed: 02/21/2024]
Abstract
Astrocyte-derived pyruvate is considered to have neuroprotective functions. In order to investigate the processes that are involved in astrocytic pyruvate release, we used primary rat astrocyte cultures as model system. Depending on the incubation conditions and medium composition, astrocyte cultures established extracellular steady state pyruvate concentrations in the range between 150 µM and 300 µM. During incubations for up to 2 weeks in DMEM culture medium, the extracellular pyruvate concentration remained almost constant for days, while the extracellular lactate concentration increased continuously during the incubation into the millimolar concentration range as long as glucose was present. In an amino acid-free incubation buffer, glucose-fed astrocytes released pyruvate with an initial rate of around 60 nmol/(h × mg) and after around 5 h an almost constant extracellular pyruvate concentration was established that was maintained for several hours. Extracellular pyruvate accumulation was also observed, if glucose had been replaced by mannose, fructose, lactate or alanine. Glucose-fed astrocyte cultures established similar extracellular steady state concentrations of pyruvate by releasing pyruvate into pyruvate-free media or by consuming excess of extracellular pyruvate. Inhibition of the monocarboxylate transporter MCT1 by AR-C155858 lowered extracellular pyruvate accumulation, while inhibition of mitochondrial pyruvate uptake by UK5099 increased the extracellular pyruvate concentration. Finally, the presence of the uncoupler BAM15 or of the respiratory chain inhibitor antimycin A almost completely abolished extracellular pyruvate accumulation. The data presented demonstrate that cultured astrocytes establish a transient extracellular steady state concentration of pyruvate which is strongly affected by modulation of the mitochondrial pyruvate metabolism.
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Affiliation(s)
- Nadine Denker
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry) and Centre for Environmental Research and Sustainable Technologies, University of Bremen, P.O. Box 330440, 28334, Bremen, Germany
| | - Ralf Dringen
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry) and Centre for Environmental Research and Sustainable Technologies, University of Bremen, P.O. Box 330440, 28334, Bremen, Germany.
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3
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Andersen JV, Westi EW, Griem-Krey N, Skotte NH, Schousboe A, Aldana BI, Wellendorph P. Deletion of CaMKIIα disrupts glucose metabolism, glutamate uptake, and synaptic energetics in the cerebral cortex. J Neurochem 2024; 168:704-718. [PMID: 36949663 DOI: 10.1111/jnc.15814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/28/2023] [Accepted: 03/20/2023] [Indexed: 03/24/2023]
Abstract
Ca2+/calmodulin-dependent protein kinase II alpha (CaMKIIα) is a key regulator of neuronal signaling and synaptic plasticity. Synaptic activity and neurotransmitter homeostasis are closely coupled to the energy metabolism of both neurons and astrocytes. However, whether CaMKIIα function is implicated in brain energy and neurotransmitter metabolism remains unclear. Here, we explored the metabolic consequences of CaMKIIα deletion in the cerebral cortex using a genetic CaMKIIα knockout (KO) mouse. Energy and neurotransmitter metabolism was functionally investigated in acutely isolated cerebral cortical slices using stable 13C isotope tracing, whereas the metabolic function of synaptosomes was assessed by the rates of glycolytic activity and mitochondrial respiration. The oxidative metabolism of [U-13C]glucose was extensively reduced in cerebral cortical slices of the CaMKIIα KO mice. In contrast, metabolism of [1,2-13C]acetate, primarily reflecting astrocyte metabolism, was unaffected. Cellular uptake, and subsequent metabolism, of [U-13C]glutamate was decreased in cerebral cortical slices of CaMKIIα KO mice, whereas uptake and metabolism of [U-13C]GABA were unaffected, suggesting selective metabolic impairments of the excitatory system. Synaptic metabolic function was maintained during resting conditions in isolated synaptosomes from CaMKIIα KO mice, but both the glycolytic and mitochondrial capacities became insufficient when the synaptosomes were metabolically challenged. Collectively, this study shows that global deletion of CaMKIIα significantly impairs cellular energy and neurotransmitter metabolism, particularly of neurons, suggesting a metabolic role of CaMKIIα signaling in the brain.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nane Griem-Krey
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Niels H Skotte
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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4
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Rae CD, Baur JA, Borges K, Dienel G, Díaz-García CM, Douglass SR, Drew K, Duarte JMN, Duran J, Kann O, Kristian T, Lee-Liu D, Lindquist BE, McNay EC, Robinson MB, Rothman DL, Rowlands BD, Ryan TA, Scafidi J, Scafidi S, Shuttleworth CW, Swanson RA, Uruk G, Vardjan N, Zorec R, McKenna MC. Brain energy metabolism: A roadmap for future research. J Neurochem 2024; 168:910-954. [PMID: 38183680 PMCID: PMC11102343 DOI: 10.1111/jnc.16032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 01/08/2024]
Abstract
Although we have learned much about how the brain fuels its functions over the last decades, there remains much still to discover in an organ that is so complex. This article lays out major gaps in our knowledge of interrelationships between brain metabolism and brain function, including biochemical, cellular, and subcellular aspects of functional metabolism and its imaging in adult brain, as well as during development, aging, and disease. The focus is on unknowns in metabolism of major brain substrates and associated transporters, the roles of insulin and of lipid droplets, the emerging role of metabolism in microglia, mysteries about the major brain cofactor and signaling molecule NAD+, as well as unsolved problems underlying brain metabolism in pathologies such as traumatic brain injury, epilepsy, and metabolic downregulation during hibernation. It describes our current level of understanding of these facets of brain energy metabolism as well as a roadmap for future research.
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Affiliation(s)
- Caroline D. Rae
- School of Psychology, The University of New South Wales, NSW 2052 & Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - Joseph A. Baur
- Department of Physiology and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karin Borges
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Gerald Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Carlos Manlio Díaz-García
- Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | | | - Kelly Drew
- Center for Transformative Research in Metabolism, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - João M. N. Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, & Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Jordi Duran
- Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Barcelona, Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, D-69120; Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Tibor Kristian
- Veterans Affairs Maryland Health Center System, Baltimore, Maryland, USA
- Department of Anesthesiology and the Center for Shock, Trauma, and Anesthesiology Research (S.T.A.R.), University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Dasfne Lee-Liu
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Región Metropolitana, Chile
| | - Britta E. Lindquist
- Department of Neurology, Division of Neurocritical Care, Gladstone Institute of Neurological Disease, University of California at San Francisco, San Francisco, California, USA
| | - Ewan C. McNay
- Behavioral Neuroscience, University at Albany, Albany, New York, USA
| | - Michael B. Robinson
- Departments of Pediatrics and System Pharmacology & Translational Therapeutics, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Douglas L. Rothman
- Magnetic Resonance Research Center and Departments of Radiology and Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Benjamin D. Rowlands
- School of Chemistry, Faculty of Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Timothy A. Ryan
- Department of Biochemistry, Weill Cornell Medicine, New York, New York, USA
| | - Joseph Scafidi
- Department of Neurology, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Susanna Scafidi
- Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - C. William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine Albuquerque, Albuquerque, New Mexico, USA
| | - Raymond A. Swanson
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, California, USA
| | - Gökhan Uruk
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, California, USA
| | - Nina Vardjan
- Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Mary C. McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Dienel GA, Schousboe A, McKenna MC, Rothman DL. A tribute to Leif Hertz: The historical context of his pioneering studies of the roles of astrocytes in brain energy metabolism, neurotransmission, cognitive functions, and pharmacology identifies important, unresolved topics for future studies. J Neurochem 2024; 168:461-495. [PMID: 36928655 DOI: 10.1111/jnc.15812] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
Leif Hertz, M.D., D.Sc. (honōris causā) (1930-2018), was one of the original and noteworthy participants in the International Conference on Brain Energy Metabolism (ICBEM) series since its inception in 1993. The biennial ICBEM conferences are organized by neuroscientists interested in energetics and metabolism underlying neural functions; they have had a high impact on conceptual and experimental advances in these fields and on promoting collaborative interactions among neuroscientists. Leif made major contributions to ICBEM discussions and understanding of metabolic and signaling characteristics of astrocytes and their roles in brain function. His studies ranged from uptake of K+ from extracellular fluid and its stimulation of astrocytic respiration, identification, and regulation of enzymes specifically or preferentially expressed in astrocytes in the glutamate-glutamine cycle of excitatory neurotransmission, a requirement for astrocytic glycogenolysis for fueling K+ uptake, involvement of glycogen in memory consolidation in the chick, and pharmacology of astrocytes. This tribute to Leif Hertz highlights his major discoveries, the high impact of his work on astrocyte-neuron interactions, and his unparalleled influence on understanding the cellular basis of brain energy metabolism. His work over six decades has helped integrate the roles of astrocytes into neurotransmission where oxidative and glycogenolytic metabolism during neurotransmitter glutamate turnover are key aspects of astrocytic energetics. Leif recognized that brain astrocytic metabolism is greatly underestimated unless the volume fraction of astrocytes is taken into account. Adjustment for pathway rates expressed per gram tissue for volume fraction indicates that astrocytes have much higher oxidative rates than neurons and astrocytic glycogen concentrations and glycogenolytic rates during sensory stimulation in vivo are similar to those in resting and exercising muscle, respectively. These novel insights are typical of Leif's astute contributions to the energy metabolism field, and his publications have identified unresolved topics that provide the neuroscience community with challenges and opportunities for future research.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, 21201, USA
| | - Douglas L Rothman
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, 06520, USA
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6
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Rabah Y, Francés R, Minatchy J, Guédon L, Desnous C, Plaçais PY, Preat T. Glycolysis-derived alanine from glia fuels neuronal mitochondria for memory in Drosophila. Nat Metab 2023; 5:2002-2019. [PMID: 37932430 PMCID: PMC10663161 DOI: 10.1038/s42255-023-00910-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/20/2023] [Indexed: 11/08/2023]
Abstract
Glucose is the primary source of energy for the brain; however, it remains controversial whether, upon neuronal activation, glucose is primarily used by neurons for ATP production or if it is partially oxidized in astrocytes, as proposed by the astrocyte-neuron lactate shuttle model for glutamatergic neurons. Thus, an in vivo picture of glucose metabolism during cognitive processes is missing. Here, we uncover in Drosophila melanogaster a glia-to-neuron alanine transfer involving alanine aminotransferase that sustains memory formation. Following associative conditioning, glycolysis in glial cells produces alanine, which is back-converted into pyruvate in cholinergic neurons of the olfactory memory center to uphold their increased mitochondrial needs. Alanine, as a mediator of glia-neuron coupling, could be an alternative to lactate in cholinergic systems. In parallel, a dedicated glial glucose transporter imports glucose specifically for long-term memory, by directly transferring it to neurons for use by the pentose phosphate pathway. Our results demonstrate in vivo the compartmentalization of glucose metabolism between neurons and glial cells during memory formation.
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Affiliation(s)
- Yasmine Rabah
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Raquel Francés
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Julia Minatchy
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Laura Guédon
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Coraline Desnous
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
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Strogulski NR, Portela LV, Polster BM, Loane DJ. Fundamental Neurochemistry Review: Microglial immunometabolism in traumatic brain injury. J Neurochem 2023; 167:129-153. [PMID: 37759406 PMCID: PMC10655864 DOI: 10.1111/jnc.15959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023]
Abstract
Traumatic brain injury (TBI) is a devastating neurological disorder caused by a physical impact to the brain that promotes diffuse damage and chronic neurodegeneration. Key mechanisms believed to support secondary brain injury include mitochondrial dysfunction and chronic neuroinflammation. Microglia and brain-infiltrating macrophages are responsible for neuroinflammatory cytokine and reactive oxygen species (ROS) production after TBI. Their production is associated with loss of homeostatic microglial functions such as immunosurveillance, phagocytosis, and immune resolution. Beyond providing energy support, mitochondrial metabolic pathways reprogram the pro- and anti-inflammatory machinery in immune cells, providing a critical immunometabolic axis capable of regulating immunologic response to noxious stimuli. In the brain, the capacity to adapt to different environmental stimuli derives, in part, from microglia's ability to recognize and respond to changes in extracellular and intracellular metabolite levels. This capacity is met by an equally plastic metabolism, capable of altering immune function. Microglial pro-inflammatory activation is associated with decreased mitochondrial respiration, whereas anti-inflammatory microglial polarization is supported by increased oxidative metabolism. These metabolic adaptations contribute to neuroimmune responses, placing mitochondria as a central regulator of post-traumatic neuroinflammation. Although it is established that profound neurometabolic changes occur following TBI, key questions related to metabolic shifts in microglia remain unresolved. These include (a) the nature of microglial mitochondrial dysfunction after TBI, (b) the hierarchical positions of different metabolic pathways such as glycolysis, pentose phosphate pathway, glutaminolysis, and lipid oxidation during secondary injury and recovery, and (c) how immunometabolism alters microglial phenotypes, culminating in chronic non-resolving neuroinflammation. In this basic neurochemistry review article, we describe the contributions of immunometabolism to TBI, detail primary evidence of mitochondrial dysfunction and metabolic impairments in microglia and macrophages, discuss how major metabolic pathways contribute to post-traumatic neuroinflammation, and set out future directions toward advancing immunometabolic phenotyping in TBI.
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Affiliation(s)
- Nathan R. Strogulski
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luis V. Portela
- Neurotrauma and Biomarkers Laboratory, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Brian M. Polster
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David J. Loane
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research Center, University of Maryland School of Medicine, Baltimore, Maryland, USA
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8
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Hone-Blanchet A, Antal B, McMahon L, Lithen A, Smith NA, Stufflebeam S, Yen YF, Lin A, Jenkins BG, Mujica-Parodi LR, Ratai EM. Acute administration of ketone beta-hydroxybutyrate downregulates 7T proton magnetic resonance spectroscopy-derived levels of anterior and posterior cingulate GABA and glutamate in healthy adults. Neuropsychopharmacology 2023; 48:797-805. [PMID: 35995971 PMCID: PMC10066400 DOI: 10.1038/s41386-022-01364-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/08/2022]
Abstract
Glucose metabolism is impaired in brain aging and several neurological conditions. Beneficial effects of ketones have been reported in the context of protecting the aging brain, however, their neurophysiological effect is still largely uncharacterized, hurdling their development as a valid therapeutic option. In this report, we investigate the neurochemical effect of the acute administration of a ketone d-beta-hydroxybutyrate (D-βHB) monoester in fasting healthy participants with ultrahigh-field proton magnetic resonance spectroscopy (MRS). In two within-subject metabolic intervention experiments, 7 T MRS data were obtained in fasting healthy participants (1) in the anterior cingulate cortex pre- and post-administration of D-βHB (N = 16), and (2) in the posterior cingulate cortex pre- and post-administration of D-βHB compared to active control glucose (N = 26). Effect of age and blood levels of D-βHB and glucose were used to further explore the effect of D-βHB and glucose on MRS metabolites. Results show that levels of GABA and Glu were significantly reduced in the anterior and posterior cortices after administration of D-βHB. Importantly, the effect was specific to D-βHB and not observed after administration of glucose. The magnitude of the effect on GABA and Glu was significantly predicted by older age and by elevation of blood levels of D-βHB. Together, our results show that administration of ketones acutely impacts main inhibitory and excitatory transmitters in the whole fasting cortex, compared to normal energy substrate glucose. Critically, such effects have an increased magnitude in older age, suggesting an increased sensitivity to ketones with brain aging.
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Affiliation(s)
- Antoine Hone-Blanchet
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Botond Antal
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Liam McMahon
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Andrew Lithen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Nathan A Smith
- Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, George Washington University School of Medicine and Health Sciences, Washington, DC, 20012, USA
- Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, 14642, USA
| | - Steven Stufflebeam
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Yi-Fen Yen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Alexander Lin
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Bruce G Jenkins
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
| | - Lilianne R Mujica-Parodi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, 11794, USA
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Eva-Maria Ratai
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA.
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9
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Andersen JV, Schousboe A. Glial Glutamine Homeostasis in Health and Disease. Neurochem Res 2023; 48:1100-1128. [PMID: 36322369 DOI: 10.1007/s11064-022-03771-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022]
Abstract
Glutamine is an essential cerebral metabolite. Several critical brain processes are directly linked to glutamine, including ammonia homeostasis, energy metabolism and neurotransmitter recycling. Astrocytes synthesize and release large quantities of glutamine, which is taken up by neurons to replenish the glutamate and GABA neurotransmitter pools. Astrocyte glutamine hereby sustains the glutamate/GABA-glutamine cycle, synaptic transmission and general brain function. Cerebral glutamine homeostasis is linked to the metabolic coupling of neurons and astrocytes, and relies on multiple cellular processes, including TCA cycle function, synaptic transmission and neurotransmitter uptake. Dysregulations of processes related to glutamine homeostasis are associated with several neurological diseases and may mediate excitotoxicity and neurodegeneration. In particular, diminished astrocyte glutamine synthesis is a common neuropathological component, depriving neurons of an essential metabolic substrate and precursor for neurotransmitter synthesis, hereby leading to synaptic dysfunction. While astrocyte glutamine synthesis is quantitatively dominant in the brain, oligodendrocyte-derived glutamine may serve important functions in white matter structures. In this review, the crucial roles of glial glutamine homeostasis in the healthy and diseased brain are discussed. First, we provide an overview of cellular recycling, transport, synthesis and metabolism of glutamine in the brain. These cellular aspects are subsequently discussed in relation to pathological glutamine homeostasis of hepatic encephalopathy, epilepsy, Alzheimer's disease, Huntington's disease and amyotrophic lateral sclerosis. Further studies on the multifaceted roles of cerebral glutamine will not only increase our understanding of the metabolic collaboration between brain cells, but may also aid to reveal much needed therapeutic targets of several neurological pathologies.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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10
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Astrocytes regulate inhibitory neurotransmission through GABA uptake, metabolism, and recycling. Essays Biochem 2023; 67:77-91. [PMID: 36806927 DOI: 10.1042/ebc20220208] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 02/23/2023]
Abstract
Synaptic regulation of the primary inhibitory neurotransmitter γ-aminobutyric acid (GABA) is essential for brain function. Cerebral GABA homeostasis is tightly regulated through multiple mechanisms and is directly coupled to the metabolic collaboration between neurons and astrocytes. In this essay, we outline and discuss the fundamental roles of astrocytes in regulating synaptic GABA signaling. A major fraction of synaptic GABA is removed from the synapse by astrocytic uptake. Astrocytes utilize GABA as a metabolic substrate to support glutamine synthesis. The astrocyte-derived glutamine is subsequently transferred to neurons where it serves as the primary precursor of neuronal GABA synthesis. The flow of GABA and glutamine between neurons and astrocytes is collectively termed the GABA-glutamine cycle and is essential to sustain GABA synthesis and inhibitory signaling. In certain brain areas, astrocytes are even capable of synthesizing and releasing GABA to modulate inhibitory transmission. The majority of oxidative GABA metabolism in the brain takes place in astrocytes, which also leads to synthesis of the GABA-related metabolite γ-hydroxybutyric acid (GHB). The physiological roles of endogenous GHB remain unclear, but may be related to regulation of tonic inhibition and synaptic plasticity. Disrupted inhibitory signaling and dysfunctional astrocyte GABA handling are implicated in several diseases including epilepsy and Alzheimer's disease. Synaptic GABA homeostasis is under astrocytic control and astrocyte GABA uptake, metabolism, and recycling may therefore serve as relevant targets to ameliorate pathological inhibitory signaling.
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11
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Consumption and Metabolism of Extracellular Pyruvate by Cultured Rat Brain Astrocytes. Neurochem Res 2022; 48:1438-1454. [PMID: 36495387 PMCID: PMC10066139 DOI: 10.1007/s11064-022-03831-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
AbstractBrain astrocytes are considered as glycolytic cell type, but these cells also produce ATP via mitochondrial oxidative phosphorylation. Exposure of cultured primary astrocytes in a glucose-free medium to extracellular substrates that are known to be metabolised by mitochondrial pathways, including pyruvate, lactate, beta-hydroxybutyrate, alanine and acetate, revealed that among the substrates investigated extracellular pyruvate was most efficiently consumed by astrocytes. Extracellular pyruvate was consumed by the cells almost proportional to time over hours in a concentration-dependent manner with apparent Michaelis–Menten kinetics [Km = 0.6 ± 0.1 mM, Vmax = 5.1 ± 0.8 nmol/(min × mg protein)]. The astrocytic consumption of pyruvate was strongly impaired in the presence of the monocarboxylate transporter 1 (MCT1) inhibitor AR-C155858 or by application of a 10-times excess of the MCT1 substrates lactate or beta-hydroxybutyrate. Pyruvate consumption by viable astrocytes was inhibited in the presence of UK5099, an inhibitor of the mitochondrial pyruvate carrier, or after application of the respiratory chain inhibitor antimycin A. In contrast, the mitochondrial uncoupler BAM15 strongly accelerated cellular pyruvate consumption. Lactate and alanine accounted after 3 h of incubation with pyruvate for around 60% and 10%, respectively, of the pyruvate consumed by the cells. These results demonstrate that consumption of extracellular pyruvate by astrocytes involves uptake via MCT1 and that the velocity of pyruvate consumption is strongly modified by substances that affect the entry of pyruvate into mitochondria or the activity of mitochondrial respiration.
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12
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Matthiesen I, Nasiri R, Tamashiro Orrego A, Winkler TE, Herland A. Metabolic Assessment of Human Induced Pluripotent Stem Cells-Derived Astrocytes and Fetal Primary Astrocytes: Lactate and Glucose Turnover. BIOSENSORS 2022; 12:839. [PMID: 36290976 PMCID: PMC9599592 DOI: 10.3390/bios12100839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/27/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Astrocytes represent one of the main cell types in the brain and play a crucial role in brain functions, including supplying the energy demand for neurons. Moreover, they are important regulators of metabolite levels. Glucose uptake and lactate production are some of the main observable metabolic actions of astrocytes. To gain insight into these processes, it is essential to establish scalable and functional sources for in vitro studies of astrocytes. In this study, we compared the metabolic turnover of glucose and lactate in astrocytes derived from human induced pluripotent stem cell (hiPSC)-derived Astrocytes (hiAstrocytes) as a scalable astrocyte source to human fetal astrocytes (HFAs). Using a user-friendly, commercial flow-based biosensor, we could verify that hiAstrocytes are as glycogenic as their fetal counterparts, but their normalized metabolic turnover is lower. Specifically, under identical culture conditions in a defined media, HFAs have 2.3 times higher levels of lactate production compared to hiAstrocytes. In terms of glucose, HFAs have 2.1 times higher consumption levels than hiAstrocytes at 24 h. Still, as we describe their glycogenic phenotype, our study demonstrates the use of hiAstrocytes and flow-based biosensors for metabolic studies of astrocyte function.
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Affiliation(s)
- Isabelle Matthiesen
- Division of Micro and Nanosystems, Department of Intelligent Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- CVRM Safety, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, 43150 Gothenburg, Sweden
| | - Rohollah Nasiri
- Division of Micro and Nanosystems, Department of Intelligent Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- Division of Nanobiotechnology, Department of Protein Science, Science for Life Laboratory, KTH Royal Institute of Technology, 17165 Solna, Sweden
- AIMES, Center for the Advancement of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, 17177 Solna, Sweden
| | - Alessandra Tamashiro Orrego
- Division of Nanobiotechnology, Department of Protein Science, Science for Life Laboratory, KTH Royal Institute of Technology, 17165 Solna, Sweden
| | - Thomas E. Winkler
- Division of Micro and Nanosystems, Department of Intelligent Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- Institute of Microtechnology & Center of Pharmaceutical Engineering, Technische Universität Braunschweig, 38106 Braunschweig, Germany
| | - Anna Herland
- Division of Micro and Nanosystems, Department of Intelligent Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 10044 Stockholm, Sweden
- Division of Nanobiotechnology, Department of Protein Science, Science for Life Laboratory, KTH Royal Institute of Technology, 17165 Solna, Sweden
- AIMES, Center for the Advancement of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, 17177 Solna, Sweden
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13
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Metabolism of Exogenous [2,4- 13C]β-Hydroxybutyrate following Traumatic Brain Injury in 21-22-Day-Old Rats: An Ex Vivo NMR Study. Metabolites 2022; 12:metabo12080710. [PMID: 36005582 PMCID: PMC9414923 DOI: 10.3390/metabo12080710] [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: 06/15/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 02/04/2023] Open
Abstract
Traumatic brain injury (TBI) is leading cause of morbidity in young children. Acute dysregulation of oxidative glucose metabolism within the first hours after injury is a hallmark of TBI. The developing brain relies on ketones as well as glucose for energy. Thus, the aim of this study was to determine the metabolism of ketones early after TBI injury in the developing brain. Following the controlled cortical impact injury model of TBI, 21-22-day-old rats were infused with [2,4-13C]β-hydroxybutyrate during the acute (4 h) period after injury. Using ex vivo 13C-NMR spectroscopy, we determined that 13C-β-hydroxybutyrate (13C-BHB) metabolism was increased in both the ipsilateral and contralateral sides of the brain after TBI. Incorporation of the label was significantly higher in glutamate than glutamine, indicating that 13C-BHB metabolism was higher in neurons than astrocytes in both sham and injured brains. Our results show that (i) ketone metabolism was significantly higher in both the ipsilateral and contralateral sides of the injured brain after TBI; (ii) ketones were extensively metabolized by both astrocytes and neurons, albeit higher in neurons; (iii) the pyruvate recycling pathway determined by incorporation of the label from the metabolism of 13C-BHB into lactate was upregulated in the immature brain after TBI.
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14
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Andersen JV, Schousboe A, Verkhratsky A. Astrocyte energy and neurotransmitter metabolism in Alzheimer's disease: integration of the glutamate/GABA-glutamine cycle. Prog Neurobiol 2022; 217:102331. [PMID: 35872221 DOI: 10.1016/j.pneurobio.2022.102331] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 02/06/2023]
Abstract
Astrocytes contribute to the complex cellular pathology of Alzheimer's disease (AD). Neurons and astrocytes function in close collaboration through neurotransmitter recycling, collectively known as the glutamate/GABA-glutamine cycle, which is essential to sustain neurotransmission. Neurotransmitter recycling is intimately linked to astrocyte energy metabolism. In the course of AD, astrocytes undergo extensive metabolic remodeling, which may profoundly affect the glutamate/GABA-glutamine cycle. The consequences of altered astrocyte function and metabolism in relation to neurotransmitter recycling are yet to be comprehended. Metabolic alterations of astrocytes in AD deprive neurons of metabolic support, thereby contributing to synaptic dysfunction and neurodegeneration. In addition, several astrocyte-specific components of the glutamate/GABA-glutamine cycle, including glutamine synthesis and synaptic neurotransmitter uptake, are perturbed in AD. Integration of the complex astrocyte biology within the context of AD is essential for understanding the fundamental mechanisms of the disease, while restoring astrocyte metabolism may serve as an approach to arrest or even revert clinical progression of AD.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, 48011 Bilbao, Spain; Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102 Vilnius, Lithuania.
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15
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Li Y, Thelen KM, Fernández KM, Nelli R, Fardisi M, Rajput M, Trottier NL, Contreras GA, Moeser AJ. Developmental alterations of intestinal SGLT1 and GLUT2 induced by early weaning coincides with persistent low-grade metabolic inflammation in female pigs. Am J Physiol Gastrointest Liver Physiol 2022; 322:G346-G359. [PMID: 34984921 PMCID: PMC9076411 DOI: 10.1152/ajpgi.00207.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Early-life adversity (ELA) is linked with the increased risk for inflammatory and metabolic diseases in later life, but the mechanisms remain poorly understood. Intestinal epithelial glucose transporters sodium-glucose-linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) are the major route for intestinal glucose uptake but have also received increased attention as modulators of inflammatory and metabolic diseases. Here, we tested the hypothesis that early weaning (EW) in pigs, an established model of ELA, alters the development of epithelial glucose transporters and coincides with elevated markers of metabolic inflammation. The jejunum and ileum of 90-day-old pigs previously exposed to EW (16 days wean age), exhibited reduced SGLT1 activity (by ∼ 30%, P < 0.05) than late weaned (LW, 28 days wean age) controls. In contrast, GLUT2-mediated glucose transport was increased (P = 0.003) in EW pigs than in LW pigs. Reciprocal changes in SGLT1- and GLUT2-mediated transport coincided with transporter protein expression in the intestinal brush-border membranes (BBMs) that were observed at 90 days and 150 days of age. Ileal SGLT1-mediated glucose transport and BBM expression were inhibited by the β-adrenergic receptor (βAR) blocker propranolol in EW and LW pigs. In contrast, propranolol enhanced ileal GLUT2-mediated glucose transport (P = 0.015) and brush-border membrane vesicle (BBMV) abundance (P = 0.035) in LW pigs, but not in EW pigs. Early-weaned pigs exhibited chronically elevated blood glucose and C-reactive protein (CRP) levels, and adipocyte hypertrophy and upregulated adipogenesis-related gene expression in visceral adipose tissue. Altered development of intestinal glucose transporters by EW could underlie the increased risk for later life inflammatory and metabolic diseases.NEW & NOTEWORTHY These studies reveal that early-life adversity in the form of early weaning in pigs causes a developmental shift in intestinal glucose transport from SGLT1 toward GLUT2-mediated transport. Early weaning also induced markers of metabolic inflammation including persistent elevations in blood glucose and the inflammatory marker CRP, along with increased visceral adiposity. Altered intestinal glucose transport might contribute to increased risk for inflammatory and metabolic diseases associated with early-life adversity.
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Affiliation(s)
- Yihang Li
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Kyan M. Thelen
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Karina Matos Fernández
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Rahul Nelli
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Mahsa Fardisi
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Mrigendra Rajput
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Nathalie L. Trottier
- 3Department of Animal Science, Michigan State University, East Lansing, Michigan
| | - Genaro A. Contreras
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
| | - Adam J. Moeser
- 1Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan,2Department of Physiology, Michigan State University, East Lansing, Michigan
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16
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Reyes-Ortega P, Soria-Ortiz MB, Rodríguez VM, Vázquez-Martínez EO, Díaz-Muñoz M, Reyes-Haro D. Anorexia disrupts glutamate-glutamine homeostasis associated with astroglia in the prefrontal cortex of young female rats. Behav Brain Res 2021; 420:113715. [PMID: 34906609 DOI: 10.1016/j.bbr.2021.113715] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 11/19/2021] [Accepted: 12/09/2021] [Indexed: 01/01/2023]
Abstract
Anorexia nervosa (AN) is an eating disorder characterized by self-starvation and excessive weight loss with a notorious prevalence in young women. The neurobiology of AN is unknown but murine models, like dehydration induced anorexia (DIA), reproduce weight loss and avoidance of food despite its availability. Astrocytes are known to provide homeostatic support to neurons, but it is little explored if anorexia affects this function. In this study, we tested if DIA disrupts glutamate-glutamine homeostasis associated with astrocytes in the prefrontal cortex (PFC) of young female rats. Our results showed that anorexia reduced the redox state, as well as endogenous glutamate and glutamine. These effects correlated with a reduced expression of the glutamate transporters (GLT-1 and GLAST) and glutamine synthetase, all of them are preferentially expressed by astrocytes. Accordingly, the expression of GFAP was reduced. Anorexia reduced the astrocyte density, promoted a de-ramified morphology, and augmented the de-ramified/ramified astrocyte ratio in the medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC), but not in the motor cortex (M2). The increase of a de-ramified phenotype correlated with increased expression of vimentin and nestin. Based on these results, we conclude that anorexia disrupts glutamate-glutamine homeostasis and the redox state associated with astrocyte dysfunction.
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Affiliation(s)
- Pamela Reyes-Ortega
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico
| | - María Berenice Soria-Ortiz
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico
| | - Verónica M Rodríguez
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico
| | - Eva Olivia Vázquez-Martínez
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico
| | - Mauricio Díaz-Muñoz
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico
| | - Daniel Reyes-Haro
- Universidad Nacional Autónoma de México, Instituto de Neurobiología, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro CP76230, Mexico.
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17
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Sood A, Preeti K, Fernandes V, Khatri DK, Singh SB. Glia: A major player in glutamate-GABA dysregulation-mediated neurodegeneration. J Neurosci Res 2021; 99:3148-3189. [PMID: 34748682 DOI: 10.1002/jnr.24977] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 12/16/2022]
Abstract
The imbalance between glutamate and γ-aminobutyric acid (GABA) results in the loss of synaptic strength leading to neurodegeneration. The dogma on the field considered neurons as the main players in this excitation-inhibition (E/I) balance. However, current strategies focusing only on neurons have failed to completely understand this condition, bringing up the importance of glia as an alternative modulator for neuroinflammation as glia alter the activity of neurons and is a source of both neurotrophic and neurotoxic factors. This review's primary goal is to illustrate the role of glia over E/I balance in the central nervous system and its interaction with neurons. Rather than focusing only on the neuronal targets, we take a deeper look at glial receptors and proteins that could also be explored as drug targets, as they are early responders to neurotoxic insults. This review summarizes the neuron-glia interaction concerning GABA and glutamate, possible targets, and its involvement in the E/I imbalance in neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis.
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Affiliation(s)
- Anika Sood
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Kumari Preeti
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Valencia Fernandes
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Dharmendra Kumar Khatri
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Shashi Bala Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
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18
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Sowers JL, Sowers ML, Shavkunov AS, Hawkins BE, Wu P, DeWitt DS, Prough DS, Zhang K. Traumatic brain injury induces region-specific glutamate metabolism changes as measured by multiple mass spectrometry methods. iScience 2021; 24:103108. [PMID: 34622161 PMCID: PMC8479783 DOI: 10.1016/j.isci.2021.103108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 06/14/2021] [Accepted: 09/08/2021] [Indexed: 11/02/2022] Open
Abstract
The release of excess glutamate following traumatic brain injury (TBI) results in glutamate excitotoxicity and metabolic energy failure. Endogenous mechanisms for reducing glutamate concentration in the brain parenchyma following TBI are poorly understood. Using multiple mass spectrometry approaches, we examined TBI-induced changes to glutamate metabolism. We present evidence that glutamate concentration can be reduced by glutamate oxidation via a "truncated" tricarboxylic acid cycle coupled to the urea cycle. This process reduces glutamate levels, generates carbon for energy metabolism, leads to citrulline accumulation, and produces nitric oxide. Several key metabolites are identified by metabolomics in support of this mechanism and the locations of these metabolites in the injured hemisphere are demonstrated by MALDI-MS imaging. The results of this study establish the advantages of multiple mass spectrometry approaches and provide insights into glutamate metabolism following TBI that could lead to improved treatment approaches.
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Affiliation(s)
- James L Sowers
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, TX 77555, USA.,Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Mark L Sowers
- MD-PhD Combined Degree Program, University of Texas Medical Branch, Galveston, TX 77555, USA.,Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alexander S Shavkunov
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Bridget E Hawkins
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA.,Research Innovation and Scientific Excellence (RISE) Center, School of Nursing, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Ping Wu
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Douglas S DeWitt
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Donald S Prough
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kangling Zhang
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA.,The Moody Project for Translational Traumatic Brain Injury Research, University of Texas Medical Branch, Galveston, TX 77555, USA
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19
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Andersen JV, Markussen KH, Jakobsen E, Schousboe A, Waagepetersen HS, Rosenberg PA, Aldana BI. Glutamate metabolism and recycling at the excitatory synapse in health and neurodegeneration. Neuropharmacology 2021; 196:108719. [PMID: 34273389 DOI: 10.1016/j.neuropharm.2021.108719] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 02/08/2023]
Abstract
Glutamate is the primary excitatory neurotransmitter of the brain. Cellular homeostasis of glutamate is of paramount importance for normal brain function and relies on an intricate metabolic collaboration between neurons and astrocytes. Glutamate is extensively recycled between neurons and astrocytes in a process known as the glutamate-glutamine cycle. The recycling of glutamate is closely linked to brain energy metabolism and is essential to sustain glutamatergic neurotransmission. However, a considerable amount of glutamate is also metabolized and serves as a metabolic hub connecting glucose and amino acid metabolism in both neurons and astrocytes. Disruptions in glutamate clearance, leading to neuronal overstimulation and excitotoxicity, have been implicated in several neurodegenerative diseases. Furthermore, the link between brain energy homeostasis and glutamate metabolism is gaining attention in several neurological conditions. In this review, we provide an overview of the dynamics of synaptic glutamate homeostasis and the underlying metabolic processes with a cellular focus on neurons and astrocytes. In particular, we review the recently discovered role of neuronal glutamate uptake in synaptic glutamate homeostasis and discuss current advances in cellular glutamate metabolism in the context of Alzheimer's disease and Huntington's disease. Understanding the intricate regulation of glutamate-dependent metabolic processes at the synapse will not only increase our insight into the metabolic mechanisms of glutamate homeostasis, but may reveal new metabolic targets to ameliorate neurodegeneration.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Kia H Markussen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Paul A Rosenberg
- Department of Neurology and the F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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20
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Limón ID, Angulo-Cruz I, Sánchez-Abdon L, Patricio-Martínez A. Disturbance of the Glutamate-Glutamine Cycle, Secondary to Hepatic Damage, Compromises Memory Function. Front Neurosci 2021; 15:578922. [PMID: 33584185 PMCID: PMC7873464 DOI: 10.3389/fnins.2021.578922] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Glutamate fulfils many vital functions both at a peripheral level and in the central nervous system (CNS). However, hyperammonemia and hepatic failure induce alterations in glutamatergic neurotransmission, which may be the main cause of hepatic encephalopathy (HE), an imbalance which may explain damage to both learning and memory. Cognitive and motor alterations in hyperammonemia may be caused by a deregulation of the glutamate-glutamine cycle, particularly in astrocytes, due to the blocking of the glutamate excitatory amino-acid transporters 1 and 2 (EAAT1, EAAT2). Excess extracellular glutamate triggers mechanisms involving astrocyte-mediated inflammation, including the release of Ca2+-dependent glutamate from astrocytes, the appearance of excitotoxicity, the formation of reactive oxygen species (ROS), and cell damage. Glutamate re-uptake not only prevents excitotoxicity, but also acts as a vital component in synaptic plasticity and function. The present review outlines the evidence of the relationship between hepatic damage, such as that occurring in HE and hyperammonemia, and changes in glutamine synthetase function, which increase glutamate concentrations in the CNS. These conditions produce dysfunction in neuronal communication. The present review also includes data indicating that hyperammonemia is related to the release of a high level of pro-inflammatory factors, such as interleukin-6, by astrocytes. This neuroinflammatory condition alters the function of the membrane receptors, such as N-methyl-D-aspartate (NMDA), (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) AMPA, and γ-aminobutyric acid (GABA), thus affecting learning and spatial memory. Data indicates that learning and spatial memory, as well as discriminatory or other information acquisition processes in the CNS, are damaged by the appearance of hyperammonemia and, moreover, are associated with a reduction in the production of cyclic guanosine monophosphate (cGMP). Therefore, increased levels of pharmacologically controlled cGMP may be used as a therapeutic tool for improving learning and memory in patients with HE, hyperammonemia, cerebral oedema, or reduced intellectual capacity.
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Affiliation(s)
| | - Isael Angulo-Cruz
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Lesli Sánchez-Abdon
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Aleidy Patricio-Martínez
- Laboratorio de Neurofarmacología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
- Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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21
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Alherz M, Lee D, Alshangiti A, Roddy D, O'Keeffe G, White R, Barry D. The Growth Response to Beta-Hydroxybutyrate in SH-SY5Y Neuroblastoma Cells is Suppressed by Glucose and Pyruvate Supplementation. Neurochem Res 2021; 46:701-709. [PMID: 33389384 DOI: 10.1007/s11064-020-03203-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 01/07/2023]
Abstract
Neuroblastoma (NB) is a childhood malignancy of the sympathetic nervous system and is commonly studied using the SH-SY5Y cell line. Its neoplastic and neurodevelopmental manifestations are characterised by a high glucose demand which maintains its high proliferative capacity. This metabolic phenotype may be utilised in dietary therapies such as the ketone diet which alter substrate availability and thus starve NB cells of their preferred biosynthetic requirements. However, the effects of ketone metabolism on cancer growth remain poorly understood due to the involvement of other metabolic substrates in experimental paradigms and complexities underlying the Warburg effect. We investigated how the primary ketone body beta-hydroxybutyrate (βOHB) affects the growth of SH-SY5Y NB cells in the presence or absence of culture metabolic substrates. We demonstrated that while glucose deprivation reduced the growth and viability of SH-SY5Y cells, they proliferated and were initially unaffected by the addition of βOHB. However, a growth response to βOHB was subsequently revealed in media containing low levels of glucose, as well as in glucose and pyruvate deprived conditions. These data shed light on the roles of metabolic substrate availability as key determinants of the responses of SH-SY5Y NB cells to ketone supplementation.
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Affiliation(s)
- Mohammad Alherz
- Department of Anatomy, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - David Lee
- Department of Anatomy, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Amnah Alshangiti
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Darren Roddy
- Department of Anatomy, Trinity College Dublin, The University of Dublin, Dublin, Ireland
| | - Gerard O'Keeffe
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Robin White
- Department of Biology, Westfield State University, Westfield, MA, 01086, USA
| | - Denis Barry
- Department of Anatomy, Trinity College Dublin, The University of Dublin, Dublin, Ireland.
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22
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Bukke VN, Archana M, Villani R, Romano AD, Wawrzyniak A, Balawender K, Orkisz S, Beggiato S, Serviddio G, Cassano T. The Dual Role of Glutamatergic Neurotransmission in Alzheimer's Disease: From Pathophysiology to Pharmacotherapy. Int J Mol Sci 2020; 21:ijms21207452. [PMID: 33050345 PMCID: PMC7589203 DOI: 10.3390/ijms21207452] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/28/2020] [Accepted: 10/05/2020] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related dementia and neurodegenerative disorder, characterized by Aβ and tau protein deposition impairing learning, memory and suppressing synaptic plasticity of neurons. Increasing evidence suggests that there is a link between the glucose and glutamate alterations with age that down-regulates glucose utilization reducing glutamate levels in AD patients. Deviations in brain energy metabolism reinforce the development of AD by hampering glutamate levels in the brain. Glutamate is a nonessential amino acid and the major excitatory neurotransmitter synthesized from glucose. Alterations in cerebral glucose and glutamate levels precede the deposition of Aβ plaques. In the brain, over 40% of neuronal synapses are glutamatergic and disturbances in glutamatergic function have been implicated in pathophysiology of AD. Nevertheless, targeting the glutamatergic system seems to be a promising strategy to develop novel, improved therapeutics for AD. Here, we review data supporting the involvement of the glutamatergic system in AD pathophysiology as well as the efficacy of glutamatergic agents in this neurodegenerative disorder. We also discuss exciting new prospects for the development of improved therapeutics for this devastating disorder.
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Affiliation(s)
- Vidyasagar Naik Bukke
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Moola Archana
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Rosanna Villani
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Antonino Davide Romano
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Agata Wawrzyniak
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Krzysztof Balawender
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Stanislaw Orkisz
- Morphological Science Department of Human Anatomy, Medical Faculty University of Rzeszów, 35-310 Rzeszów, Poland; (A.W.); (K.B.); (S.O.)
| | - Sarah Beggiato
- Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, 66100 Chieti, Italy;
| | - Gaetano Serviddio
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy; (M.A.); (R.V.); (A.D.R.); (G.S.)
| | - Tommaso Cassano
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
- Correspondence:
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23
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Mine M, Mizuguchi H, Takayanagi T. Kinetic analysis of substrate competition in enzymatic reactions with β-D-galactosidase by capillary electrophoresis / dynamic frontal analysis. J Pharm Biomed Anal 2020; 188:113390. [PMID: 32512255 DOI: 10.1016/j.jpba.2020.113390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 02/01/2023]
Abstract
Competitive inhibition between two substrates with an enzyme is investigated by capillary electrophoresis/dynamic frontal analysis (CE/DFA). Enzymatic hydrolyses of o-nitrophenyl β-D-galactopyranoside and p-nitrophenyl β-D-galactopyranoside with β-D-galactosidase were examined as a model competitive reaction. A sample solution containing the two substrates was injected into a capillary filled with a separation buffer containing an enzyme. Enzymatic hydrolysis occurred during the electrophoresis, and the products of o-nitrophenol and p-nitrophenol were continuously formed and resolved from the sample zone. Two-steps plateau signal was detected with the two-substrate solutions based on the difference in the effective electrophoretic mobility of o-nitrophenol and p-nitrophenol. Michaelis-Menten constants and inhibition constants were determined with the plateau heights. Usefulness of CE/DFA on competitive inhibition analysis is demonstrated in this study.
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Affiliation(s)
- Masanori Mine
- Graduate School of Advanced Technology and Science, Tokushima University, 2-1 Minamijyousanjima-cho, Tokushima 770-8506, Japan
| | - Hitoshi Mizuguchi
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minamijyousanjima-cho, Tokushima 770-8506, Japan
| | - Toshio Takayanagi
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minamijyousanjima-cho, Tokushima 770-8506, Japan.
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24
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Zhang C, Feng X, He L, Zhang Y, Shao L. The interrupted effect of autophagic flux and lysosomal function induced by graphene oxide in p62-dependent apoptosis of F98 cells. J Nanobiotechnology 2020; 18:52. [PMID: 32188458 PMCID: PMC7081710 DOI: 10.1186/s12951-020-00605-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Graphene oxide (GO) nanoparticles (NPs) have been widely applied in various fields, especially in biomedical applications. Extensive studies have suggested that GO can pass through the blood-brain barrier (BBB) and induce abnormal autophagy and cytotoxicity in the central nervous system (CNS). However, the effect and specific mechanism of GO on astrocytes, the most abundant cells in the brain still has not been extensively investigated. RESULTS In this study, we systematically explored the toxicity and mechanism of GO exposure in the rat astroglioma-derived F98 cell line using molecular biological techniques (immunofluorescence staining, flow cytometry and Western blot) at the subcellular level and the signaling pathway level. Cells exposed to GO exhibited decreased cell viability and increased lactate dehydrogenase (LDH) release in a concentration- and time-dependent manner. GO-induced autophagy was evidenced by transmission electron microscopy (TEM) and immunofluorescence staining. Western blots showed that LC3II/I and p62 were upregulated and PI3K/Akt/mTOR was downregulated. Detection of lysosomal acidity and cathepsin B activity assay indicated the impairment of lysosomal function. Annexin V-FITC-PI detection showed the occurrence of apoptosis after GO exposure. The decrease in mitochondrial membrane potential (MMP) with an accompanying upregulation of cleaved caspase-3 and Bax/Bcl-2 further suggested that endogenous signaling pathways were involved in GO-induced apoptosis. CONCLUSION The exposure of F98 cells to GO can elicit concentration- and time-dependent toxicological effects. Additionally, increased autophagic response can be triggered after GO treatment and that the blocking of autophagy flux plays a vital role in GO cytotoxicity, which was determined to be related to dysfunction of lysosomal degradation. Importantly, the abnormal accumulation of autophagic substrate p62 protein can induce capase-3-mediated apoptosis. Inhibition of abnormal accumulation of autophagic cargo could alleviate the occurrence of GO-induced apoptosis in F98 cells.
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Affiliation(s)
- Chao Zhang
- Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, 510280, China
| | - Xiaoli Feng
- Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, 510280, China
| | - Longwen He
- Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, 510280, China
| | - Yaqing Zhang
- Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, 510280, China
| | - Longquan Shao
- Stomatological Hospital, Southern Medical University (Guangdong Provincial Stomatological Hospital), Guangzhou, 510280, China.
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering, Guangzhou, 510515, China.
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25
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Morris G, Maes M, Berk M, Carvalho AF, Puri BK. Nutritional ketosis as an intervention to relieve astrogliosis: Possible therapeutic applications in the treatment of neurodegenerative and neuroprogressive disorders. Eur Psychiatry 2020; 63:e8. [PMID: 32093791 PMCID: PMC8057392 DOI: 10.1192/j.eurpsy.2019.13] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Nutritional ketosis, induced via either the classical ketogenic diet or the use of emulsified medium-chain triglycerides, is an established treatment for pharmaceutical resistant epilepsy in children and more recently in adults. In addition, the use of oral ketogenic compounds, fractionated coconut oil, very low carbohydrate intake, or ketone monoester supplementation has been reported to be potentially helpful in mild cognitive impairment, Parkinson’s disease, schizophrenia, bipolar disorder, and autistic spectrum disorder. In these and other neurodegenerative and neuroprogressive disorders, there are detrimental effects of oxidative stress, mitochondrial dysfunction, and neuroinflammation on neuronal function. However, they also adversely impact on neurone–glia interactions, disrupting the role of microglia and astrocytes in central nervous system (CNS) homeostasis. Astrocytes are the main site of CNS fatty acid oxidation; the resulting ketone bodies constitute an important source of oxidative fuel for neurones in an environment of glucose restriction. Importantly, the lactate shuttle between astrocytes and neurones is dependent on glycogenolysis and glycolysis, resulting from the fact that the astrocytic filopodia responsible for lactate release are too narrow to accommodate mitochondria. The entry into the CNS of ketone bodies and fatty acids, as a result of nutritional ketosis, has effects on the astrocytic glutamate–glutamine cycle, glutamate synthase activity, and on the function of vesicular glutamate transporters, EAAT, Na+, K+-ATPase, Kir4.1, aquaporin-4, Cx34 and KATP channels, as well as on astrogliosis. These mechanisms are detailed and it is suggested that they would tend to mitigate the changes seen in many neurodegenerative and neuroprogressive disorders. Hence, it is hypothesized that nutritional ketosis may have therapeutic applications in such disorders.
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Affiliation(s)
- Gerwyn Morris
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia
| | - Michael Maes
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia.,Department of Psychiatry, Chulalongkorn University, Faculty of Medicine, Bangkok, Thailand
| | - Michael Berk
- Deakin University, IMPACT Strategic Research Centre, Barwon Health, School of Medicine, Geelong, Victoria, Australia.,Deakin University, CMMR Strategic Research Centre, School of Medicine, Geelong, Victoria, Australia.,Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - André F Carvalho
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.,Centre for Addiction and Mental Health (CAMH), Toronto, Ontario, Canada
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26
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Robinson MB, Lee ML, DaSilva S. Glutamate Transporters and Mitochondria: Signaling, Co-compartmentalization, Functional Coupling, and Future Directions. Neurochem Res 2020; 45:526-540. [PMID: 32002773 DOI: 10.1007/s11064-020-02974-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
In addition to being an amino acid that is incorporated into proteins, glutamate is the most abundant neurotransmitter in the mammalian CNS, the precursor for the inhibitory neurotransmitter γ-aminobutyric acid, and one metabolic step from the tricarboxylic acid cycle intermediate α-ketoglutarate. Extracellular glutamate is cleared by a family of Na+-dependent transporters. These transporters are variably expressed by all cell types in the nervous system, but the bulk of clearance is into astrocytes. GLT-1 and GLAST (also called EAAT2 and EAAT1) mediate this activity and are extremely abundant proteins with their expression enriched in fine astrocyte processes. In this review, we will focus on three topics related to these astrocytic glutamate transporters. First, these transporters co-transport three Na+ ions and a H+ with each molecule of glutamate and counter-transport one K+; they are also coupled to a Cl- conductance. The movement of Na+ is sufficient to cause profound astrocytic depolarization, and the movement of H+ is linked to astrocytic acidification. In addition, the movement of Na+ can trigger the activation of Na+ co-transporters (e.g. Na+-Ca2+ exchangers). We will describe the ways in which these ionic movements have been linked as signals to brain function and/or metabolism. Second, these transporters co-compartmentalize with mitochondria, potentially providing a mechanism to supply glutamate to mitochondria as a source of fuel for the brain. We will provide an overview of the proteins involved, discuss the evidence that glutamate is oxidized, and then highlight some of the un-resolved issues related to glutamate oxidation. Finally, we will review evidence that ischemic insults (stroke or oxygen/glucose deprivation) cause changes in these astrocytic mitochondria and discuss the ways in which these changes have been linked to glutamate transport, glutamate transport-dependent signaling, and altered glutamate metabolism. We conclude with a broader summary of some of the unresolved issues.
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Affiliation(s)
- Michael B Robinson
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA.
| | - Meredith L Lee
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA
| | - Sabrina DaSilva
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, Children's Hospital of Philadelphia, University of Pennsylvania, 502N, Abramson Pediatric Research Building, 3615 Civic Center Boulevard, Philadelphia, PA, 19104-4318, USA
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27
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Bordone MP, Salman MM, Titus HE, Amini E, Andersen JV, Chakraborti B, Diuba AV, Dubouskaya TG, Ehrke E, Espindola de Freitas A, Braga de Freitas G, Gonçalves RA, Gupta D, Gupta R, Ha SR, Hemming IA, Jaggar M, Jakobsen E, Kumari P, Lakkappa N, Marsh APL, Mitlöhner J, Ogawa Y, Paidi RK, Ribeiro FC, Salamian A, Saleem S, Sharma S, Silva JM, Singh S, Sulakhiya K, Tefera TW, Vafadari B, Yadav A, Yamazaki R, Seidenbecher CI. The energetic brain - A review from students to students. J Neurochem 2019; 151:139-165. [PMID: 31318452 DOI: 10.1111/jnc.14829] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The past 20 years have resulted in unprecedented progress in understanding brain energy metabolism and its role in health and disease. In this review, which was initiated at the 14th International Society for Neurochemistry Advanced School, we address the basic concepts of brain energy metabolism and approach the question of why the brain has high energy expenditure. Our review illustrates that the vertebrate brain has a high need for energy because of the high number of neurons and the need to maintain a delicate interplay between energy metabolism, neurotransmission, and plasticity. Disturbances to the energetic balance, to mitochondria quality control or to glia-neuron metabolic interaction may lead to brain circuit malfunction or even severe disorders of the CNS. We cover neuronal energy consumption in neural transmission and basic ('housekeeping') cellular processes. Additionally, we describe the most common (glucose) and alternative sources of energy namely glutamate, lactate, ketone bodies, and medium chain fatty acids. We discuss the multifaceted role of non-neuronal cells in the transport of energy substrates from circulation (pericytes and astrocytes) and in the supply (astrocytes and microglia) and usage of different energy fuels. Finally, we address pathological consequences of disrupted energy homeostasis in the CNS.
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Affiliation(s)
- Melina Paula Bordone
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Haley E Titus
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Artem V Diuba
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatsiana G Dubouskaya
- Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Eric Ehrke
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Andiara Espindola de Freitas
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, California, USA
| | | | | | | | - Richa Gupta
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Sharon R Ha
- Baylor College of Medicine, Houston, Texas, USA
| | - Isabel A Hemming
- Brain Growth and Disease Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
| | - Minal Jaggar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Punita Kumari
- Defense Institute of Physiology and allied sciences, Defense Research and Development Organization, Timarpur, Delhi, India
| | - Navya Lakkappa
- Department of Pharmacology, JSS college of Pharmacy, Ooty, India
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany
| | - Yuki Ogawa
- The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | | | | | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Suraiya Saleem
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sorabh Sharma
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Joana M Silva
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal
| | - Shripriya Singh
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Kunjbihari Sulakhiya
- Department of Pharmacy, Indira Gandhi National Tribal University, Amarkantak, India
| | - Tesfaye Wolde Tefera
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Behnam Vafadari
- Institute of environmental medicine, UNIKA-T, Technical University of Munich, Munich, Germany
| | - Anuradha Yadav
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Reiji Yamazaki
- Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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28
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Le Foll C. Hypothalamic Fatty Acids and Ketone Bodies Sensing and Role of FAT/CD36 in the Regulation of Food Intake. Front Physiol 2019; 10:1036. [PMID: 31474875 PMCID: PMC6702519 DOI: 10.3389/fphys.2019.01036] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/29/2019] [Indexed: 12/19/2022] Open
Abstract
The obesity and type-2 diabetes epidemic is escalating and represents one of the costliest biomedical challenges confronting modern society. Moreover, the increasing consumption of high fat food is often correlated with an increase in body mass index. In people predisposed to be obese or already obese, the impaired ability of the brain to monitor and respond to alterations in fatty acid (FA) metabolism is increasingly recognized as playing a role in the pathophysiological development of these disorders. The brain senses and regulates metabolism using highly specialized nutrient-sensing neurons located mainly in the hypothalamus. The same neurons are able to detect variation in the extracellular levels of glucose, FA and ketone bodies as a way to monitor nutrient availability and to alter its own activity. In addition, glial cells such as astrocytes create major connections to neurons and form a tight relationship to closely regulate nutrient uptake and metabolism. This review will examine the different pathways by which neurons are able to detect free fatty acids (FFA) to alter its activity and how high fat diet (HFD)-astrocytes induced ketone bodies production interplays with neuronal FA sensing. The role of HFD-induced inflammation and how FA modulate the reward system will also be investigated here.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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29
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Gzielo K, Soltys Z, Rajfur Z, Setkowicz ZK. The Impact of the Ketogenic Diet on Glial Cells Morphology. A Quantitative Morphological Analysis. Neuroscience 2019; 413:239-251. [PMID: 31220541 DOI: 10.1016/j.neuroscience.2019.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 12/14/2022]
Abstract
Ketogenic diet is reported to protect against cognitive decline, drug-resistant epilepsy, Alzheimer's Disease, damaging effect of ischemic stroke and many neurological diseases. Despite mounting evidence that this dietary treatment works, the exact mechanism of its protective activity is largely unknown. Ketogenic diet acts systemically, not only changing GABA signaling in neurons, but also influencing the reliance on mitochondrial respiration, known to be disrupted in many neurological diseases. Normally, human body is driven by glucose while ketogenic diet mimics starvation and energy required for proper functioning comes from fatty acids oxidation. In the brain astrocytes are believed to be the sole neural cells capable of fatty oxidation. Here we try to explain that not exclusively neurons, but also morphological changes of astroglia and/or microglia due to different metabolic state are important for the mechanism underlying the protective role of ketogenic diet. By quantifying different parameters describing cellular morphology like ramification index or fractal dimension and using Principal Component Analysis to discover the regularities between them, we demonstrate that in normal adult rat brain, ketogenic diet itself is able to change glial morphology, indicating an important role of these underappreciated cells in the brain metabolism.
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Affiliation(s)
- K Gzielo
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.
| | - Z Soltys
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Z Rajfur
- Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Krakow, Poland
| | - Z K Setkowicz
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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30
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McKenna MC, Schuck PF, Ferreira GC. Fundamentals of CNS energy metabolism and alterations in lysosomal storage diseases. J Neurochem 2018; 148:590-599. [PMID: 30144055 DOI: 10.1111/jnc.14577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/05/2018] [Accepted: 08/22/2018] [Indexed: 01/03/2023]
Abstract
The brain has a very high requirement for energy. Adult brain relies on glucose as an energy substrate, whereas developing brain can utilize alternative substrates as well as glucose for energy and for the biosynthesis of lipids and proteins required for brain development. Metabolism provides the energy required to support all cellular functions and brain development and building blocks for macromolecules. Lysosomes are organelles involved in breakdown of biological compounds including proteins and complex lipids in the body and brain. Recent studies suggest that lysosomal dysfunction can damage neurons and/or alter neurotransmitter homeostasis. Several studies also implicate mitochondrial dysfunction in the pathophysiology of brain damage in lysosomal storage diseases. This manuscript provides a brief review of energy metabolism and the key pathways involved in metabolism in brain. Roles of lysosomes related to metabolism and neurotransmission are discussed, and evidence for mitochondrial dysfunction in several lysosomal storage diseases is presented. This article is part of the Special Issue "Lysosomal Storage Disorders".
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Patricia F Schuck
- School of Sciences, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Gustavo C Ferreira
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Rio Grande do Sul, Brazil
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31
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Ronowska A, Szutowicz A, Bielarczyk H, Gul-Hinc S, Klimaszewska-Łata J, Dyś A, Zyśk M, Jankowska-Kulawy A. The Regulatory Effects of Acetyl-CoA Distribution in the Healthy and Diseased Brain. Front Cell Neurosci 2018; 12:169. [PMID: 30050410 PMCID: PMC6052899 DOI: 10.3389/fncel.2018.00169] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/31/2018] [Indexed: 12/25/2022] Open
Abstract
Brain neurons, to support their neurotransmitter functions, require a several times higher supply of glucose than non-excitable cells. Pyruvate, the end product of glycolysis, through pyruvate dehydrogenase complex reaction, is a principal source of acetyl-CoA, which is a direct energy substrate in all brain cells. Several neurodegenerative conditions result in the inhibition of pyruvate dehydrogenase and decrease of acetyl-CoA synthesis in mitochondria. This attenuates metabolic flux through TCA in the mitochondria, yielding energy deficits and inhibition of diverse synthetic acetylation reactions in all neuronal sub-compartments. The acetyl-CoA concentrations in neuronal mitochondrial and cytoplasmic compartments are in the range of 10 and 7 μmol/L, respectively. They appear to be from 2 to 20 times lower than acetyl-CoA Km values for carnitine acetyltransferase, acetyl-CoA carboxylase, aspartate acetyltransferase, choline acetyltransferase, sphingosine kinase 1 acetyltransferase, acetyl-CoA hydrolase, and acetyl-CoA acetyltransferase, respectively. Therefore, alterations in acetyl-CoA levels alone may significantly change the rates of metabolic fluxes through multiple acetylation reactions in brain cells in different physiologic and pathologic conditions. Such substrate-dependent alterations in cytoplasmic, endoplasmic reticulum or nuclear acetylations may directly affect ACh synthesis, protein acetylations, and gene expression. Thereby, acetyl-CoA may regulate the functional and adaptative properties of neuronal and non-neuronal brain cells. The excitotoxicity-evoked intracellular zinc excess hits several intracellular targets, yielding the collapse of energy balance and impairment of the functional and structural integrity of postsynaptic cholinergic neurons. Acute disruption of brain energy homeostasis activates slow accumulation of amyloid-β1-42 (Aβ). Extra and intracellular oligomeric deposits of Aβ affect diverse transporting and signaling pathways in neuronal cells. It may combine with multiple neurotoxic signals, aggravating their detrimental effects on neuronal cells. This review presents evidences that changes of intraneuronal levels and compartmentation of acetyl-CoA may contribute significantly to neurotoxic pathomechanisms of different neurodegenerative brain disorders.
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Affiliation(s)
- Anna Ronowska
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Andrzej Szutowicz
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Hanna Bielarczyk
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Sylwia Gul-Hinc
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Joanna Klimaszewska-Łata
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Aleksandra Dyś
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Marlena Zyśk
- Department of Laboratory Medicine, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
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Jaber SM, Bordt EA, Bhatt NM, Lewis DM, Gerecht S, Fiskum G, Polster BM. Sex differences in the mitochondrial bioenergetics of astrocytes but not microglia at a physiologically relevant brain oxygen tension. Neurochem Int 2018; 117:82-90. [PMID: 28888963 PMCID: PMC5839942 DOI: 10.1016/j.neuint.2017.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/14/2017] [Accepted: 09/05/2017] [Indexed: 11/22/2022]
Abstract
Biological sex is thought to influence mitochondrial bioenergetic function. Previous respiration measurements examining brain mitochondrial sex differences were made at atmospheric oxygen using isolated brain mitochondria. Oxygen is 160 mm Hg (21%) in the atmosphere, while the oxygen tension in the brain generally ranges from ∼5 to 45 mm Hg (∼1-6% O2). This study tested the hypothesis that sex and/or brain physiological oxygen tension influence the mitochondrial bioenergetic properties of primary rat cortical astrocytes and microglia. Oxygen consumption was measured with a Seahorse XF24 cell respirometer in an oxygen-controlled environmental chamber. Strikingly, male astrocytes had a higher maximal respiration than female astrocytes when cultured and assayed at 3% O2. Three percent O2 yielded a low physiological dissolved O2 level of ∼1.2% (9.1 mm Hg) at the cell monolayer during culture and 1.2-3.0% O2 during assays. No differences in bioenergetic parameters were observed between male and female astrocytes at 21% O2 (dissolved O2 of ∼19.7%, 150 mm Hg during culture) or between either of these cell populations and female astrocytes at 3% O2. In contrast to astrocytes, microglia showed no sex differences in mitochondrial bioenergetic parameters at either oxygen level, regardless of whether they were non-stimulated or activated to a proinflammatory state. There were also no O2- or sex-dependent differences in proinflammatory TNF-α or IL-1β cytokine secretion measured at 18 h activation. Overall, results reveal an intriguing sex variance in astrocytic maximal respiration that requires additional investigation. Findings also demonstrate that sex differences can be masked by conducting experiments at non-physiological O2.
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Affiliation(s)
- Sausan M Jaber
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Evan A Bordt
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Niraj M Bhatt
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Daniel M Lewis
- Department of Chemical and Biomolecular Engineering, Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA
| | - Sharon Gerecht
- Department of Chemical and Biomolecular Engineering, Institute for NanoBioTechnology, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA; Department of Materials Science and Engineering, Johns Hopkins University, 3400 North Charles Street, Shaffer Hall 200C, Baltimore, MD 21218, USA
| | - Gary Fiskum
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA
| | - Brian M Polster
- Department of Anesthesiology, and the Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA; Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore ST., MSTF 5-34, Baltimore, MD, 21201, USA.
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33
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Vodovozov W, Schneider J, Elzoheiry S, Hollnagel JO, Lewen A, Kann O. Metabolic modulation of neuronal gamma-band oscillations. Pflugers Arch 2018; 470:1377-1389. [DOI: 10.1007/s00424-018-2156-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/06/2018] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
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Ambient but not local lactate underlies neuronal tolerance to prolonged glucose deprivation. PLoS One 2018; 13:e0195520. [PMID: 29617444 PMCID: PMC5884621 DOI: 10.1371/journal.pone.0195520] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/23/2018] [Indexed: 11/19/2022] Open
Abstract
Neurons require a nearly constant supply of ATP. Glucose is the predominant source of brain ATP, but the direct effects of prolonged glucose deprivation on neuronal viability and function remain unclear. In sparse rat hippocampal microcultures, neurons were surprisingly resilient to 16 h glucose removal in the absence of secondary excitotoxicity. Neuronal survival and synaptic transmission were unaffected by prolonged removal of exogenous glucose. Inhibition of lactate transport decreased microculture neuronal survival during concurrent glucose deprivation, suggesting that endogenously released lactate is important for tolerance to glucose deprivation. Tandem depolarization and glucose deprivation also reduced neuronal survival, and trace glucose concentrations afforded neuroprotection. Mass cultures, in contrast to microcultures, were insensitive to depolarizing glucose deprivation, a difference attributable to increased extracellular lactate levels. Removal of local astrocyte support did not reduce survival in response to glucose deprivation or alter evoked excitatory transmission, suggesting that on-demand, local lactate shuttling is not necessary for neuronal tolerance to prolonged glucose removal. Taken together, these data suggest that endogenously produced lactate available globally in the extracellular milieu sustains neurons in the absence of glucose. A better understanding of resilience mechanisms in reduced preparations could lead to therapeutic strategies aimed to bolster these mechanisms in vulnerable neuronal populations.
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Veyrat-Durebex C, Reynier P, Procaccio V, Hergesheimer R, Corcia P, Andres CR, Blasco H. How Can a Ketogenic Diet Improve Motor Function? Front Mol Neurosci 2018; 11:15. [PMID: 29434537 PMCID: PMC5790787 DOI: 10.3389/fnmol.2018.00015] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/10/2018] [Indexed: 12/12/2022] Open
Abstract
A ketogenic diet (KD) is a normocaloric diet composed by high fat (80-90%), low carbohydrate, and low protein consumption that induces fasting-like effects. KD increases ketone body (KBs) production and its concentration in the blood, providing the brain an alternative energy supply that enhances oxidative mitochondrial metabolism. In addition to its profound impact on neuro-metabolism and bioenergetics, the neuroprotective effect of specific polyunsaturated fatty acids and KBs involves pleiotropic mechanisms, such as the modulation of neuronal membrane excitability, inflammation, or reactive oxygen species production. KD is a therapy that has been used for almost a century to treat medically intractable epilepsy and has been increasingly explored in a number of neurological diseases. Motor function has also been shown to be improved by KD and/or medium-chain triglyceride diets in rodent models of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and spinal cord injury. These studies have proposed that KD may induce a modification in synaptic morphology and function, involving ionic channels, glutamatergic transmission, or synaptic vesicular cycling machinery. However, little is understood about the molecular mechanisms underlying the impact of KD on motor function and the perspectives of its use to acquire the neuromuscular effects. The aim of this review is to explore the conditions through which KD might improve motor function. First, we will describe the main consequences of KD exposure in tissues involved in motor function. Second, we will report and discuss the relevance of KD in pre-clinical and clinical trials in the major diseases presenting motor dysfunction.
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Affiliation(s)
- Charlotte Veyrat-Durebex
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, Angers, France
- INSERM 1083, CNRS, Equipe Mitolab, Institut MITOVASC, UMR 6015, Université d’Angers, Angers, France
| | - Pascal Reynier
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, Angers, France
- INSERM 1083, CNRS, Equipe Mitolab, Institut MITOVASC, UMR 6015, Université d’Angers, Angers, France
| | - Vincent Procaccio
- Département de Biochimie et Génétique, Centre Hospitalier Universitaire, Angers, France
- INSERM 1083, CNRS, Equipe Mitolab, Institut MITOVASC, UMR 6015, Université d’Angers, Angers, France
| | | | - Philippe Corcia
- INSERM U930, Université François Rabelais de Tours, Tours, France
- Service de Neurologie, Centre Hospitalier Universitaire de Tours, Tours, France
| | - Christian R. Andres
- INSERM U930, Université François Rabelais de Tours, Tours, France
- Laboratoire de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire de Tours, Tours, France
| | - Hélène Blasco
- INSERM 1083, CNRS, Equipe Mitolab, Institut MITOVASC, UMR 6015, Université d’Angers, Angers, France
- INSERM U930, Université François Rabelais de Tours, Tours, France
- Laboratoire de Biochimie et Biologie Moléculaire, Centre Hospitalier Universitaire de Tours, Tours, France
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36
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Hertz L, Chen Y. Integration between Glycolysis and Glutamate-Glutamine Cycle Flux May Explain Preferential Glycolytic Increase during Brain Activation, Requiring Glutamate. Front Integr Neurosci 2017. [PMID: 28890689 DOI: 10.3389/fnint.2017.00018+10.3389/fnint.2017.00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The 1988 observation by Fox et al. (1988) that brief intense brain activation increases glycolysis (pyruvate formation from glucose) much more than oxidative metabolism has been abundantly confirmed. Specifically glycolytic increase was unexpected because the amount of ATP it generates is much smaller than that formed by subsequent oxidative metabolism of pyruvate. The present article shows that preferential glycolysis can be explained by metabolic processes associated with activation of the glutamate-glutamine cycle. The flux in this cycle, which is essential for production of transmitter glutamate and GABA, equals 75% of brain glucose utilization and each turn is associated with utilization of ~1 glucose molecule. About one half of the association between cycle flux and glucose metabolism occurs during neuronal conversion of glutamine to glutamate in a process similar to the malate-aspartate shuttle (MAS) except that glutamate is supplied from glutamine, not formed from α-ketoglutarate (αKG) as during operation of conventional MAS. Regular MAS function is triggered by one oxidative process in the cytosol during glycolysis causing NAD+ reduction to NADH. Since NADH cannot cross the mitochondrial membrane (MEM) for oxidation NAD+ is re-generated by conversion of cytosolic oxaloacetate (OAA) to malate, which enters the mitochondria for oxidation and in a cyclic process regenerates cytosolic OAA. Therefore MAS as well as the "pseudo-MAS" necessary for neuronal glutamate formation can only operate together with cytosolic reduction of NAD+ to NADH. The major process causing NAD+ reduction is glycolysis which therefore also must occur during neuronal conversion of glutamine to glutamate and may energize vesicular glutamate uptake which preferentially uses glycolytically derived energy. Another major contributor to the association between glutamate-glutamine cycle and glucose utilization is the need for astrocytic pyruvate to generate glutamate. Although some oxidative metabolism occurs during glutamate formation it is only one half of that during normal tricarboxylic acid (TCA) cycle function. Glutamate's receptor stimulation leads to potassium ion (K+) release and astrocytic uptake, preferentially fueled by glycolysis and followed by release and neuronal re-accumulation. The activation-induced preferential glycolysis diminishes with continued activation and is followed by an increased ratio between oxidative metabolism and glycolysis, reflecting oxidation of generated glutamate and accumulated lactate.
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Affiliation(s)
- Leif Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical UniversityShenyang, China
| | - Ye Chen
- Henry M. Jackson FoundationBethesda, MD, United States
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37
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Hertz L, Chen Y. Integration between Glycolysis and Glutamate-Glutamine Cycle Flux May Explain Preferential Glycolytic Increase during Brain Activation, Requiring Glutamate. Front Integr Neurosci 2017; 11:18. [PMID: 28890689 PMCID: PMC5574930 DOI: 10.3389/fnint.2017.00018] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/11/2017] [Indexed: 11/13/2022] Open
Abstract
The 1988 observation by Fox et al. (1988) that brief intense brain activation increases glycolysis (pyruvate formation from glucose) much more than oxidative metabolism has been abundantly confirmed. Specifically glycolytic increase was unexpected because the amount of ATP it generates is much smaller than that formed by subsequent oxidative metabolism of pyruvate. The present article shows that preferential glycolysis can be explained by metabolic processes associated with activation of the glutamate-glutamine cycle. The flux in this cycle, which is essential for production of transmitter glutamate and GABA, equals 75% of brain glucose utilization and each turn is associated with utilization of ~1 glucose molecule. About one half of the association between cycle flux and glucose metabolism occurs during neuronal conversion of glutamine to glutamate in a process similar to the malate-aspartate shuttle (MAS) except that glutamate is supplied from glutamine, not formed from α-ketoglutarate (αKG) as during operation of conventional MAS. Regular MAS function is triggered by one oxidative process in the cytosol during glycolysis causing NAD+ reduction to NADH. Since NADH cannot cross the mitochondrial membrane (MEM) for oxidation NAD+ is re-generated by conversion of cytosolic oxaloacetate (OAA) to malate, which enters the mitochondria for oxidation and in a cyclic process regenerates cytosolic OAA. Therefore MAS as well as the "pseudo-MAS" necessary for neuronal glutamate formation can only operate together with cytosolic reduction of NAD+ to NADH. The major process causing NAD+ reduction is glycolysis which therefore also must occur during neuronal conversion of glutamine to glutamate and may energize vesicular glutamate uptake which preferentially uses glycolytically derived energy. Another major contributor to the association between glutamate-glutamine cycle and glucose utilization is the need for astrocytic pyruvate to generate glutamate. Although some oxidative metabolism occurs during glutamate formation it is only one half of that during normal tricarboxylic acid (TCA) cycle function. Glutamate's receptor stimulation leads to potassium ion (K+) release and astrocytic uptake, preferentially fueled by glycolysis and followed by release and neuronal re-accumulation. The activation-induced preferential glycolysis diminishes with continued activation and is followed by an increased ratio between oxidative metabolism and glycolysis, reflecting oxidation of generated glutamate and accumulated lactate.
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Affiliation(s)
- Leif Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical UniversityShenyang, China
| | - Ye Chen
- Henry M. Jackson FoundationBethesda, MD, United States
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38
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Hertz L, Chen Y. Integration between Glycolysis and Glutamate-Glutamine Cycle Flux May Explain Preferential Glycolytic Increase during Brain Activation, Requiring Glutamate. Front Integr Neurosci 2017. [PMID: 28890689 DOI: 10.3389/fnint.2017.00018 10.3389/fnint.2017.00018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The 1988 observation by Fox et al. (1988) that brief intense brain activation increases glycolysis (pyruvate formation from glucose) much more than oxidative metabolism has been abundantly confirmed. Specifically glycolytic increase was unexpected because the amount of ATP it generates is much smaller than that formed by subsequent oxidative metabolism of pyruvate. The present article shows that preferential glycolysis can be explained by metabolic processes associated with activation of the glutamate-glutamine cycle. The flux in this cycle, which is essential for production of transmitter glutamate and GABA, equals 75% of brain glucose utilization and each turn is associated with utilization of ~1 glucose molecule. About one half of the association between cycle flux and glucose metabolism occurs during neuronal conversion of glutamine to glutamate in a process similar to the malate-aspartate shuttle (MAS) except that glutamate is supplied from glutamine, not formed from α-ketoglutarate (αKG) as during operation of conventional MAS. Regular MAS function is triggered by one oxidative process in the cytosol during glycolysis causing NAD+ reduction to NADH. Since NADH cannot cross the mitochondrial membrane (MEM) for oxidation NAD+ is re-generated by conversion of cytosolic oxaloacetate (OAA) to malate, which enters the mitochondria for oxidation and in a cyclic process regenerates cytosolic OAA. Therefore MAS as well as the "pseudo-MAS" necessary for neuronal glutamate formation can only operate together with cytosolic reduction of NAD+ to NADH. The major process causing NAD+ reduction is glycolysis which therefore also must occur during neuronal conversion of glutamine to glutamate and may energize vesicular glutamate uptake which preferentially uses glycolytically derived energy. Another major contributor to the association between glutamate-glutamine cycle and glucose utilization is the need for astrocytic pyruvate to generate glutamate. Although some oxidative metabolism occurs during glutamate formation it is only one half of that during normal tricarboxylic acid (TCA) cycle function. Glutamate's receptor stimulation leads to potassium ion (K+) release and astrocytic uptake, preferentially fueled by glycolysis and followed by release and neuronal re-accumulation. The activation-induced preferential glycolysis diminishes with continued activation and is followed by an increased ratio between oxidative metabolism and glycolysis, reflecting oxidation of generated glutamate and accumulated lactate.
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Affiliation(s)
- Leif Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical UniversityShenyang, China
| | - Ye Chen
- Henry M. Jackson FoundationBethesda, MD, United States
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Lundgaard I, Lu ML, Yang E, Peng W, Mestre H, Hitomi E, Deane R, Nedergaard M. Glymphatic clearance controls state-dependent changes in brain lactate concentration. J Cereb Blood Flow Metab 2017; 37:2112-2124. [PMID: 27481936 PMCID: PMC5464705 DOI: 10.1177/0271678x16661202] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Brain lactate concentration is higher during wakefulness than in sleep. However, it is unknown why arousal is linked to an increase in brain lactate and why lactate declines within minutes of sleep. Here, we show that the glymphatic system is responsible for state-dependent changes in brain lactate concentration. Suppression of glymphatic function via acetazolamide treatment, cisterna magna puncture, aquaporin 4 deletion, or changes in body position reduced the decline in brain lactate normally observed when awake mice transition into sleep or anesthesia. Concurrently, the same manipulations diminished accumulation of lactate in cervical, but not in inguinal lymph nodes when mice were anesthetized. Thus, our study suggests that brain lactate is an excellent biomarker of the sleep-wake cycle and increases further during sleep deprivation, because brain lactate is inversely correlated with glymphatic-lymphatic clearance. This analysis provides fundamental new insight into brain energy metabolism by demonstrating that glucose that is not fully oxidized can be exported as lactate via glymphatic-lymphatic fluid transport.
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Affiliation(s)
- Iben Lundgaard
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Minh Lon Lu
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA.,2 Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Ezra Yang
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Weiguo Peng
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Humberto Mestre
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Emi Hitomi
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Rashid Deane
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA
| | - Maiken Nedergaard
- 1 Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester, Rochester, NY, USA.,3 Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Szutowicz A, Bielarczyk H, Zyśk M, Dyś A, Ronowska A, Gul-Hinc S, Klimaszewska-Łata J. Early and Late Pathomechanisms in Alzheimer's Disease: From Zinc to Amyloid-β Neurotoxicity. Neurochem Res 2017; 42:891-904. [PMID: 28039593 PMCID: PMC5357490 DOI: 10.1007/s11064-016-2154-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 11/05/2022]
Abstract
There are several systemic and intracerebral pathologic conditions, which limit provision and utilization of energy precursor metabolites in neuronal cells. Energy deficits cause excessive depolarization of neuronal cells triggering glutamate-zinc evoked excitotoxic cascade. The intracellular zinc excess hits several intraneuronal targets yielding collapse of energy balance and impairment functional and structural impairments cholinergic neurons. Disturbances in metabolism of acetyl-CoA, which is a direct precursor for energy, acetylcholine, N-acetyl-L-aspartate and acetylated proteins synthesis, play an important role in these pathomechanisms. Disruption of brain homeostasis activates slow accumulation of amyloid-β 1-42 , which extra and intracellular oligomeric deposits disrupt diverse transporting and signaling processes in all membrane structures of the cell. Both neurotoxic signals may combine aggravating detrimental effects on neuronal cell. Different neuroglial and neuronal cell types may display differential susceptibility to similar pathogenic insults depending on specific features of their energy and functional parameters. This review, basing on findings gained from cellular and animal models of Alzheimer's disease, discusses putative energy/acetyl-CoA dependent mechanism in early and late stages of neurodegeneration.
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Affiliation(s)
- Andrzej Szutowicz
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland.
| | - Hanna Bielarczyk
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
| | - Marlena Zyśk
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
| | - Aleksandra Dyś
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
| | - Anna Ronowska
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
| | - Sylwia Gul-Hinc
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
| | - Joanna Klimaszewska-Łata
- Department of Laboratory Medicine, Medical University of Gdańsk, Ul. Dębinki 7, 80-211, Gdansk, Poland
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Hertz L, Rothman DL. Glutamine-Glutamate Cycle Flux Is Similar in Cultured Astrocytes and Brain and Both Glutamate Production and Oxidation Are Mainly Catalyzed by Aspartate Aminotransferase. BIOLOGY 2017; 6:biology6010017. [PMID: 28245547 PMCID: PMC5372010 DOI: 10.3390/biology6010017] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/06/2017] [Accepted: 02/14/2017] [Indexed: 01/15/2023]
Abstract
The glutamine-glutamate cycle provides neurons with astrocyte-generated glutamate/γ-aminobutyric acid (GABA) and oxidizes glutamate in astrocytes, and it returns released transmitter glutamate/GABA to neurons after astrocytic uptake. This review deals primarily with the glutamate/GABA generation/oxidation, although it also shows similarity between metabolic rates in cultured astrocytes and intact brain. A key point is identification of the enzyme(s) converting astrocytic α-ketoglutarate to glutamate and vice versa. Most experiments in cultured astrocytes, including those by one of us, suggest that glutamate formation is catalyzed by aspartate aminotransferase (AAT) and its degradation by glutamate dehydrogenase (GDH). Strongly supported by results shown in Table 1 we now propose that both reactions are primarily catalyzed by AAT. This is possible because the formation occurs in the cytosol and the degradation in mitochondria and they are temporally separate. High glutamate/glutamine concentrations abolish the need for glutamate production from α-ketoglutarate and due to metabolic coupling between glutamate synthesis and oxidation these high concentrations render AAT-mediated glutamate oxidation impossible. This necessitates the use of GDH under these conditions, shown by insensitivity of the oxidation to the transamination inhibitor aminooxyacetic acid (AOAA). Experiments using lower glutamate/glutamine concentration show inhibition of glutamate oxidation by AOAA, consistent with the coupled transamination reactions described here.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Liaoning 110000, China.
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Radiology and Biomedical Engineering, Yale University, New Haven, CT 06520, USA.
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42
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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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Madji Hounoum B, Mavel S, Coque E, Patin F, Vourc'h P, Marouillat S, Nadal-Desbarats L, Emond P, Corcia P, Andres CR, Raoul C, Blasco H. Wildtype motoneurons, ALS-Linked SOD1 mutation and glutamate profoundly modify astrocyte metabolism and lactate shuttling. Glia 2017; 65:592-605. [PMID: 28139855 DOI: 10.1002/glia.23114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/28/2016] [Accepted: 12/29/2016] [Indexed: 01/09/2023]
Abstract
The selective degeneration of motoneuron that typifies amyotrophic lateral sclerosis (ALS) implicates non-cell-autonomous effects of astrocytes. However, mechanisms underlying astrocyte-mediated neurotoxicity remain largely unknown. According to the determinant role of astrocyte metabolism in supporting neuronal function, we propose to explore the metabolic status of astrocytes exposed to ALS-associated conditions. We found a significant metabolic dysregulation including purine, pyrimidine, lysine, and glycerophospholipid metabolism pathways in astrocytes expressing an ALS-causing mutated superoxide dismutase-1 (SOD1) when co-cultured with motoneurons. SOD1 astrocytes exposed to glutamate revealed a significant modification of the astrocyte metabolic fingerprint. More importantly, we observed that SOD1 mutation and glutamate impact the cellular shuttling of lactate between astrocytes and motoneurons with a decreased in extra- and intra-cellular lactate levels in astrocytes. Based on the emergent strategy of metabolomics, this work provides novel insight for understanding metabolic dysfunction of astrocytes in ALS conditions and opens the perspective of therapeutics targets through focusing on these metabolic pathways. GLIA 2017 GLIA 2017;65:592-605.
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Affiliation(s)
- Blandine Madji Hounoum
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France
| | - Sylvie Mavel
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France
| | - Emmanuelle Coque
- The Neuroscience Institute Montpellier, INSERM U1051, Saint Eloi Hospital, Montpellier, France
| | - Franck Patin
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Bretonneau, CHRU de Tours, Tours, France
| | - Patrick Vourc'h
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Bretonneau, CHRU de Tours, Tours, France
| | - Sylviane Marouillat
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France
| | - Lydie Nadal-Desbarats
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Plateforme Scientifique et Technique "Analyses des Systèmes Biologiques" PST-ASB, Université François-Rabelais, 37032, Tours Cedex 1, France
| | - Patrick Emond
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Plateforme Scientifique et Technique "Analyses des Systèmes Biologiques" PST-ASB, Université François-Rabelais, 37032, Tours Cedex 1, France
| | - Philippe Corcia
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Centre SLA, Service de Neurologie, CHRU de Tours, Tours, France
| | - Christian R Andres
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Bretonneau, CHRU de Tours, Tours, France
| | - Cédric Raoul
- The Neuroscience Institute Montpellier, INSERM U1051, Saint Eloi Hospital, Montpellier, France
| | - Hélène Blasco
- Université François-Rabelais, INSERM U930 "Imagerie et Cerveau," CHRU de Tours, Tours, France.,Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Bretonneau, CHRU de Tours, Tours, France
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Béland-Millar A, Larcher J, Courtemanche J, Yuan T, Messier C. Effects of Systemic Metabolic Fuels on Glucose and Lactate Levels in the Brain Extracellular Compartment of the Mouse. Front Neurosci 2017; 11:7. [PMID: 28154523 PMCID: PMC5243849 DOI: 10.3389/fnins.2017.00007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/04/2017] [Indexed: 01/11/2023] Open
Abstract
Classic neuroenergetic research has emphasized the role of glucose, its transport and its metabolism in sustaining normal neural function leading to the textbook statement that it is the necessary and sole metabolic fuel of the mammalian brain. New evidence, including the Astrocyte-to-Neuron Lactate Shuttle hypothesis, suggests that the brain can use other metabolic substrates. To further study that possibility, we examined the effect of intraperitoneally administered metabolic fuels (glucose, fructose, lactate, pyruvate, ß-hydroxybutyrate, and galactose), and insulin, on blood, and extracellular brain levels of glucose and lactate in the adult male CD1 mouse. Primary motor cortex extracellular levels of glucose and lactate were monitored in freely moving mice with the use of electrochemical electrodes. Blood concentration of these same metabolites were obtained by tail vein sampling and measured with glucose and lactate meters. Blood and extracellular fluctuations of glucose and lactate were monitored for a 2-h period. We found that the systemic injections of glucose, fructose, lactate, pyruvate, and ß-hydroxybutyrate increased blood lactate levels. Apart for a small transitory rise in brain extracellular lactate levels, the main effect of the systemic injection of glucose, fructose, lactate, pyruvate, and ß-hydroxybutyrate was an increase in brain extracellular glucose levels. Systemic galactose injections produced a small rise in blood glucose and lactate but almost no change in brain extracellular lactate and glucose. Systemic insulin injections led to a decrease in blood glucose and a small rise in blood lactate; however brain extracellular glucose and lactate monotonically decreased at the same rate. Our results support the concept that the brain is able to use alternative fuels and the current experiments suggest some of the mechanisms involved.
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Affiliation(s)
| | - Jeremy Larcher
- School of Psychology, University of Ottawa Ottawa, ON, Canada
| | | | - Tina Yuan
- School of Psychology, University of Ottawa Ottawa, ON, Canada
| | - Claude Messier
- School of Psychology, University of Ottawa Ottawa, ON, Canada
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Differential Presynaptic ATP Supply for Basal and High-Demand Transmission. J Neurosci 2017; 37:1888-1899. [PMID: 28093477 DOI: 10.1523/jneurosci.2712-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/21/2022] Open
Abstract
The relative contributions of glycolysis and oxidative phosphorylation to neuronal presynaptic energy demands are unclear. In rat hippocampal neurons, ATP production by either glycolysis or oxidative phosphorylation alone sustained basal evoked synaptic transmission for up to 20 min. However, combined inhibition of both ATP sources abolished evoked transmission. Neither action potential propagation failure nor depressed Ca2+ influx explained loss of evoked synaptic transmission. Rather, inhibition of ATP synthesis caused massive spontaneous vesicle exocytosis, followed by arrested endocytosis, accounting for the disappearance of evoked postsynaptic currents. In contrast to its weak effects on basal transmission, inhibition of oxidative phosphorylation alone depressed recovery from vesicle depletion. Local astrocytic lactate shuttling was not required. Instead, either ambient monocarboxylates or neuronal glycolysis was sufficient to supply requisite substrate. In summary, basal transmission can be sustained by glycolysis, but strong presynaptic demands are met preferentially by oxidative phosphorylation, which can be maintained by bulk but not local monocarboxylates or by neuronal glycolysis.SIGNIFICANCE STATEMENT Neuronal energy levels are critical for proper CNS function, but the relative roles for the two main sources of ATP production, glycolysis and oxidative phosphorylation, in fueling presynaptic function in unclear. Either glycolysis or oxidative phosphorylation can fuel low-frequency synaptic function and inhibiting both underlies loss of synaptic transmission via massive vesicle release and subsequent failure to endocytose lost vesicles. Oxidative phosphorylation, fueled by either glycolysis or endogenously released monocarboxylates, can fuel more metabolically demanding tasks such as vesicle recovery after depletion. Our work demonstrates the flexible nature of fueling presynaptic function to maintain synaptic function.
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46
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Glia plasma membrane transporters: Key players in glutamatergic neurotransmission. Neurochem Int 2016; 98:46-55. [DOI: 10.1016/j.neuint.2016.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/07/2016] [Accepted: 04/06/2016] [Indexed: 12/27/2022]
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Hohnholt MC, Andersen VH, Bak LK, Waagepetersen HS. Glucose, Lactate and Glutamine but not Glutamate Support Depolarization-Induced Increased Respiration in Isolated Nerve Terminals. Neurochem Res 2016; 42:191-201. [DOI: 10.1007/s11064-016-2036-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/12/2016] [Accepted: 08/16/2016] [Indexed: 12/28/2022]
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48
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Le Foll C, Levin BE. Fatty acid-induced astrocyte ketone production and the control of food intake. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1186-92. [PMID: 27122369 PMCID: PMC4935491 DOI: 10.1152/ajpregu.00113.2016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/22/2016] [Indexed: 11/22/2022]
Abstract
Obesity and Type 2 diabetes are major worldwide public health issues today. A relationship between total fat intake and obesity has been found. In addition, the mechanisms of long-term and excessive high-fat diet (HFD) intake in the development of obesity still need to be elucidated. The ventromedial hypothalamus (VMH) is a major site involved in the regulation of glucose and energy homeostasis where "metabolic sensing neurons" integrate metabolic signals from the periphery. Among these signals, fatty acids (FA) modulate the activity of VMH neurons using the FA translocator/CD36, which plays a critical role in the regulation of energy and glucose homeostasis. During low-fat diet (LFD) intake, FA are oxidized by VMH astrocytes to fuel their ongoing metabolic needs. However, HFD intake causes VMH astrocytes to use FA to generate ketone bodies. We postulate that these astrocyte-derived ketone bodies are exported to neurons where they produce excess ATP and reactive oxygen species, which override CD36-mediated FA sensing and act as a signal to decrease short-term food intake. On a HFD, VMH astrocyte-produced ketones reduce elevated caloric intake to LFD levels after 3 days in rats genetically predisposed to resist (DR) diet-induced obesity (DIO), but not leptin-resistant DIO rats. This suggests that, while VMH ketone production on a HFD can contribute to protection from obesity, the inherent leptin resistance overrides this inhibitory action of ketone bodies on food intake. Thus, astrocytes and neurons form a tight metabolic unit that is able to monitor circulating nutrients to alter food intake and energy homeostasis.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland; and
| | - Barry E Levin
- Department of Neurology, Rutgers, New Jersey Medical School, Newark, New Jersey
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Mendez-Flores OG, Hernández-Kelly LC, Suárez-Pozos E, Najimi M, Ortega A. Coupling of glutamate and glucose uptake in cultured Bergmann glial cells. Neurochem Int 2016; 98:72-81. [PMID: 27184733 DOI: 10.1016/j.neuint.2016.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 04/25/2016] [Accepted: 05/02/2016] [Indexed: 11/17/2022]
Abstract
Glutamate, the main excitatory neurotransmitter in the vertebrate brain, exerts its actions through specific membrane receptors present in neurons and glial cells. Over-stimulation of glutamate receptors results in neuronal death, phenomena known as excitotoxicity. A family of sodium-dependent, glutamate uptake transporters mainly expressed in glial cells, removes the amino acid from the synaptic cleft preventing neuronal death. The sustained sodium influx associated to glutamate removal in glial cells, activates the sodium/potassium ATPase restoring the ionic balance, additionally, glutamate entrance activates glutamine synthetase, both events are energy demanding, therefore glia cells increase their ATP expenditure favouring glucose uptake, and triggering several signal transduction pathways linked to proper neuronal glutamate availability, via the glutamate/glutamine shuttle. To further characterize these complex transporters interactions, we used the well-established model system of cultured chick cerebellum Bergmann glia cells. A time and dose-dependent increase in the activity, plasma membrane localization and protein levels of glucose transporters was detected upon d-aspartate exposure. Interestingly, this increase is the result of a protein kinase C-dependent signaling cascade. Furthermore, a glutamate-dependent glucose and glutamate transporters co-immunoprecipitation was detected. These results favour the notion that glial cells are involved in glutamatergic neuronal physiology.
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Affiliation(s)
- Orquidia G Mendez-Flores
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Luisa C Hernández-Kelly
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Edna Suárez-Pozos
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Mustapha Najimi
- Laboratory of Pediatric Hepatology and Cell Therapy, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St Luc, Université catholique de Louvain, 1200 Brussels, Belgium
| | - Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico.
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50
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Astrocyte Cultures Mimicking Brain Astrocytes in Gene Expression, Signaling, Metabolism and K + Uptake and Showing Astrocytic Gene Expression Overlooked by Immunohistochemistry and In Situ Hybridization. Neurochem Res 2016; 42:254-271. [PMID: 26818759 DOI: 10.1007/s11064-016-1828-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/01/2016] [Accepted: 01/04/2016] [Indexed: 01/31/2023]
Abstract
Based on differences in gene expression between cultured astrocytes and freshly isolated brain astrocytes it has been claimed that cultured astrocytes poorly reflect the characteristics of their in vivo counterparts. This paper shows that this is not the case with the cultures of mouse astrocytes we have used since 1978. The culture is prepared following guidelines provided by Drs. Monique Sensenbrenner and John Booher, with the difference that dibutyryl cyclic AMP is added to the culture medium from the beginning of the third week. This addition has only minor effects on glucose and glutamate metabolism, but it is crucial for effects by elevated K+ concentrations and for Ca2+ homeostasis, important aspects of astrocyte function. Work by Liang Peng and her colleagues has shown identity between not only gene expression but also drug-induced gene upregulations and editings in astrocytes cultured by this method and astrocytes freshly isolated from brains of drug-treated animals. Dr. Norenberg's laboratory has demonstrated identical upregulation of the cotransporter NKCC1 in ammonia-exposed astrocytes and rats with liver failure. Similarity between cultured and freshly isolated astrocytes has also been shown in metabolism, K+ uptake and several aspects of signaling. However, others have shown that the gene for the glutamate transporter GLT1 is not expressed, and rat cultures show some abnormalities in K+ effects. Nevertheless, the overall reliability of the cultured cells is important because immunohistochemistry and in situ hybridization poorly demonstrate many astrocytic genes, e.g., those of nucleoside transporters, and even microarray analysis of isolated cells can be misleading.
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