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Lin P, Lane AN, Fan TWM. NMR-Based Stable Isotope Tracing of Cancer Metabolism. Methods Mol Biol 2025; 2855:457-504. [PMID: 39354323 DOI: 10.1007/978-1-0716-4116-3_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2024]
Abstract
NMR is widely used for metabolite profiling (metabolomics, metabonomics) particularly of various readily obtainable biofluids such as plasma and urine. It is especially valuable for stable isotope tracer studies to track metabolic pathways under control or perturbed conditions in a wide range of cell models as well as animal models and human subjects. NMR has unique properties for utilizing stable isotopes to edit or simplify otherwise complex spectra acquired in vitro and in vivo, while quantifying the level of enrichment at specific atomic positions in various metabolites (i.e., isotopomer distribution analysis).In this protocol, we give an overview with specific protocols for NMR-based stable isotope-resolved metabolomics, or SIRM, with a workflow from administration of isotope-enriched precursors, via sample preparation through to NMR data collection and reduction. We focus on indirect detection of common NMR-active stable isotopes including 13C, 15N, 31P, and 2H, using a variety of 1H-based two-dimensional experiments. We also include the application and analyses of multiplex tracer experiments.
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Affiliation(s)
- Penghui Lin
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, Lexington, KY, USA.
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, Lexington, KY, USA
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Lane AN, Higashi RM, Fan TWM. Challenges of Spatially Resolved Metabolism in Cancer Research. Metabolites 2024; 14:383. [PMID: 39057706 PMCID: PMC11278851 DOI: 10.3390/metabo14070383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 06/28/2024] [Accepted: 07/07/2024] [Indexed: 07/28/2024] Open
Abstract
Stable isotope-resolved metabolomics comprises a critical set of technologies that can be applied to a wide variety of systems, from isolated cells to whole organisms, to define metabolic pathway usage and responses to perturbations such as drugs or mutations, as well as providing the basis for flux analysis. As the diversity of stable isotope-enriched compounds is very high, and with newer approaches to multiplexing, the coverage of metabolism is now very extensive. However, as the complexity of the model increases, including more kinds of interacting cell types and interorgan communication, the analytical complexity also increases. Further, as studies move further into spatially resolved biology, new technical problems have to be overcome owing to the small number of analytes present in the confines of a single cell or cell compartment. Here, we review the overall goals and solutions made possible by stable isotope tracing and their applications to models of increasing complexity. Finally, we discuss progress and outstanding difficulties in high-resolution spatially resolved tracer-based metabolic studies.
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Affiliation(s)
- Andrew N. Lane
- Department of Toxicology and Cancer Biology and Markey Cancer Center, University of Kentucky, 789 S. Limestone St., Lexington, KY 40536, USA; (R.M.H.); (T.W.-M.F.)
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Chowdhury GMI, Behar KL, Mason GF, Rothman DL, de Graaf RA. Measurement of neuro-energetics and neurotransmission in the rat olfactory bulb using 1H and 1H-[ 13C] NMR spectroscopy. NMR IN BIOMEDICINE 2024; 37:e4957. [PMID: 37088548 PMCID: PMC10590826 DOI: 10.1002/nbm.4957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/03/2023]
Abstract
The olfactory bulb (OB) plays a fundamental role in the sense of smell and has been implicated in several pathologies, including Alzheimer's disease. Despite its importance, high metabolic activity and unique laminar architecture, the OB is not frequently studied using MRS methods, likely due to the small size and challenging location. Here we present a detailed metabolic characterization of OB metabolism, in terms of both static metabolite concentrations using 1H MRS and metabolic fluxes associated with neuro-energetics and neurotransmission by tracing the dynamic 13C flow from intravenously administered [1,6-13C2]-glucose, [2-13C]-glucose and [2-13C]-acetate to downstream metabolites, including [4-13C]-glutamate, [4-13C]-glutamine and [2-13C]-GABA. The unique laminar architecture and associated metabolism of the OB, distinctly different from that of the cerebral cortex, is characterized by elevated GABA and glutamine levels, as well as increased GABAergic and astroglial energy metabolism and neurotransmission. The results show that, despite the technical challenges, high-quality 1H and 1H-[13C] MR spectra can be obtained from the rat OB in vivo. The derived metabolite concentrations and metabolic rates demonstrate a unique metabolic profile for the OB. The metabolic model provides a solid basis for future OB studies on functional activation or pathological conditions.
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Affiliation(s)
- Golam M. I. Chowdhury
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kevin L. Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F. Mason
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L. Rothman
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Robin A. de Graaf
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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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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Westi EW, Andersen JV, Aldana BI. Using stable isotope tracing to unravel the metabolic components of neurodegeneration: Focus on neuron-glia metabolic interactions. Neurobiol Dis 2023; 182:106145. [PMID: 37150307 DOI: 10.1016/j.nbd.2023.106145] [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: 02/23/2023] [Revised: 04/17/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023] Open
Abstract
Disrupted brain metabolism is a critical component of several neurodegenerative diseases. Energy metabolism of both neurons and astrocytes is closely connected to neurotransmitter recycling via the glutamate/GABA-glutamine cycle. Neurons and astrocytes hereby work in close metabolic collaboration which is essential to sustain neurotransmission. Elucidating the mechanistic involvement of altered brain metabolism in disease progression has been aided by the advance of techniques to monitor cellular metabolism, in particular by mapping metabolism of substrates containing stable isotopes, a technique known as isotope tracing. Here we review key aspects of isotope tracing including advantages, drawbacks and applications to different cerebral preparations. In addition, we narrate how isotope tracing has facilitated the discovery of central metabolic features in neurodegeneration with a focus on the metabolic cooperation between neurons and astrocytes.
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Affiliation(s)
- Emil W Westi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Ip KL, Thomas MA, Behar KL, de Graaf RA, De Feyter HM. Mapping of exogenous choline uptake and metabolism in rat glioblastoma using deuterium metabolic imaging (DMI). Front Cell Neurosci 2023; 17:1130816. [PMID: 37187610 PMCID: PMC10175635 DOI: 10.3389/fncel.2023.1130816] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Introduction There is a lack of robust metabolic imaging techniques that can be routinely applied to characterize lesions in patients with brain tumors. Here we explore in an animal model of glioblastoma the feasibility to detect uptake and metabolism of deuterated choline and describe the tumor-to-brain image contrast. Methods RG2 cells were incubated with choline and the level of intracellular choline and its metabolites measured in cell extracts using high resolution 1H NMR. In rats with orthotopically implanted RG2 tumors deuterium metabolic imaging (DMI) was applied in vivo during, as well as 1 day after, intravenous infusion of 2H9-choline. In parallel experiments, RG2-bearing rats were infused with [1,1',2,2'-2H4]-choline and tissue metabolite extracts analyzed with high resolution 2H NMR to identify molecule-specific 2H-labeling in choline and its metabolites. Results In vitro experiments indicated high uptake and fast phosphorylation of exogenous choline in RG2 cells. In vivo DMI studies revealed a high signal from the 2H-labeled pool of choline + metabolites (total choline, 2H-tCho) in the tumor lesion but not in normal brain. Quantitative DMI-based metabolic maps of 2H-tCho showed high tumor-to-brain image contrast in maps acquired both during, and 24 h after deuterated choline infusion. High resolution 2H NMR revealed that DMI data acquired during 2H-choline infusion consists of free choline and phosphocholine, while the data acquired 24 h later represent phosphocholine and glycerophosphocholine. Discussion Uptake and metabolism of exogenous choline was high in RG2 tumors compared to normal brain, resulting in high tumor-to-brain image contrast on DMI-based metabolic maps. By varying the timing of DMI data acquisition relative to the start of the deuterated choline infusion, the metabolic maps can be weighted toward detection of choline uptake or choline metabolism. These proof-of-principle experiments highlight the potential of using deuterated choline combined with DMI to metabolically characterize brain tumors.
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Affiliation(s)
- Kevan L. Ip
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
| | - Monique A. Thomas
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
| | - Kevin L. Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
| | - Robin A. de Graaf
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
- Department of Biomedical Engineering, Yale University, New Haven, CT, United States
| | - Henk M. De Feyter
- Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
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Bhat UA, Kumar SA, Chakravarty S, Patel AB, Kumar A. Differential Effects of Chronic Ethanol Use on Mouse Neuronal and Astroglial Metabolic Activity. Neurochem Res 2023:10.1007/s11064-023-03922-y. [PMID: 37069415 DOI: 10.1007/s11064-023-03922-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/20/2023] [Accepted: 03/24/2023] [Indexed: 04/19/2023]
Abstract
Chronic alcohol use disorder, a major risk factor for the development of neuropsychiatric disorders including addiction to other substances, is associated with several neuropathology including perturbed neuronal and glial activities in the brain. It affects carbon metabolism in specific brain regions, and perturbs neuro-metabolite homeostasis in neuronal and glial cells. Alcohol induced changes in the brain neurochemical profile accompany the negative emotional state associated with dysregulated reward and sensitized stress response to withdrawal. However, the underlying alterations in neuro-astroglial activities and neurochemical dysregulations in brain regions after chronic alcohol use are poorly understood. This study evaluates the impact of chronic ethanol use on the regional neuro-astroglial metabolic activity using 1H-[13C]-NMR spectroscopy in conjunction with infusion of [1,6-13C2]glucose and sodium [2-13C]acetate, respectively, after 48 h of abstinence. Besides establishing detailed 13C labeling of neuro-metabolites in a brain region-specific manner, our results show chronic ethanol induced-cognitive deficits along with a reduction in total glucose oxidation rates in the hippocampus and striatum. Furthermore, using [2-13C]acetate infusion, we showed an alcohol-induced increase in astroglial metabolic activity in the hippocampus and prefrontal cortex. Interestingly, increased astroglia activity in the hippocampus and prefrontal cortex was associated with a differential expression of monocarboxylic acid transporters that are regulating acetate uptake and metabolism in the brain.
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Affiliation(s)
- Unis Ahmad Bhat
- Epigenetics and Neuropsychiatric Disorders Laboratory, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Habsiguda, Hyderabad, Telangana State (TS), 500007, India
| | - Sreemantula Arun Kumar
- Applied Biology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India
| | - Sumana Chakravarty
- Applied Biology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Anant Bahadur Patel
- Epigenetics and Neuropsychiatric Disorders Laboratory, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Habsiguda, Hyderabad, Telangana State (TS), 500007, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Habsiguda, Hyderabad, Telangana State (TS), 500007, India.
| | - Arvind Kumar
- Epigenetics and Neuropsychiatric Disorders Laboratory, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Habsiguda, Hyderabad, Telangana State (TS), 500007, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
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Roy D, Puvvada M, Kapanaiah SKT, Patel AB. Enhanced Cortical Metabolic Activity in Females and Males of a Slow Progressing Mouse Model of Amyotrophic Lateral Sclerosis. Neurochem Res 2022; 47:1765-1777. [PMID: 35347633 DOI: 10.1007/s11064-022-03568-2] [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: 12/17/2021] [Revised: 02/23/2022] [Accepted: 02/28/2022] [Indexed: 10/18/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with selective degeneration of motor neurons in the central nervous system. The pathophysiology of ALS is not well understood. We have used 1H-[13C]-NMR spectroscopy together with an administration of [1,6-13C2]glucose and [2-13C]acetate in female and male SOD1G37R mice to assess neuronal and astroglial metabolic activity, respectively, in the central nervous system in ALS condition. The female (p = 0.0008) and male (p < 0.0001) SOD1G37R mice exhibited decreased forelimb strength when compared with wild-type mice. There was a reduction in N-acetylaspartylglutamate level, and elevation in myo-inositol in the spinal cord of female and male SOD1G37R mice. The transgenic male mice exhibited increased acetate oxidation in the spinal cord (p = 0.05) and cerebral cortex (p = 0.03), while females showed an increase in the spinal cord (p = 0.02) only. As acetate is transported and preferentially metabolized in the astrocytes, the finding of increased rate of acetate oxidation in the transgenic mice is suggestive of astrocytic involvement in the pathogenesis of ALS. The rates of glucose oxidation in glutamatergic (p = 0.0004) and GABAergic neurons (p = 0.0052) were increased in the cerebral cortex of male SOD1G37R mice when compared with the controls. The female mice showed an increase in glutamatergic (p = 0.039) neurometabolic activity only. The neurometabolic activity was unperturbed in the spinal cord of either sex. These data suggest differential changes in neurometabolic activity across the central nervous system in SOD1G37R mice.
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Affiliation(s)
- Dipak Roy
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Habsiguda, Uppal Road, Hyderabad, 500007, India
| | - Madhuri Puvvada
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Habsiguda, Uppal Road, Hyderabad, 500007, India
| | - Sampath K T Kapanaiah
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Habsiguda, Uppal Road, Hyderabad, 500007, India
| | - Anant Bahadur Patel
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Habsiguda, Uppal Road, Hyderabad, 500007, India. .,Academy of Scientific and Innovative Research, Ghaziabad, 201002, India.
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Soni ND, Ramesh A, Roy D, Patel AB. Brain energy metabolism in intracerebroventricularly administered streptozotocin mouse model of Alzheimer's disease: A 1H-[ 13C]-NMR study. J Cereb Blood Flow Metab 2021; 41:2344-2355. [PMID: 33657898 PMCID: PMC8393290 DOI: 10.1177/0271678x21996176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is a very common neurodegenerative disorder. Although a majority of the AD cases are sporadic, most of the studies are conducted using transgenic models. Intracerebroventricular (ICV) administered streptozotocin (STZ) animals have been used to explore mechanisms in sporadic AD. In this study, we have investigated memory and neurometabolism of ICV-STZ-administered C57BL6/J mice. The neuronal and astroglial metabolic activity was measured in 1H-[13C]-NMR spectrum of cortical and hippocampal tissue extracts of mice infused with [1,6-13C2]glucose and [2-13C]acetate, respectively. STZ-administered mice exhibited reduced (p = 0.00002) recognition index for memory. The levels of creatine, GABA, glutamate and NAA were reduced (p ≤ 0.04), while that of myo-inositol was increased (p < 0.05) in STZ-treated mice. There was a significant (p ≤ 0.014) reduction in aspartate-C3, glutamate-C4/C3, GABA-C2 and glutamine-C4 labeling from [1,6-13C2]glucose. This resulted in decreased rate of glucose oxidation in the cerebral cortex (0.64 ± 0.05 vs. 0.77 ± 0.05 µmol/g/min, p = 0.0008) and hippocampus (0.60 ± 0.04 vs. 0.73 ± 0.07 µmol/g/min, p = 0.001) of STZ-treated mice, due to similar reductions of glucose oxidation in glutamatergic and GABAergic neurons. Additionally, reduced glutamine-C4 labeling points towards compromised synaptic neurotransmission in STZ-treated mice. These data suggest that the ICV-STZ model exhibits neurometabolic deficits typically observed in AD, and its utility in understanding the mechanism of sporadic AD.
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Affiliation(s)
- Narayan D Soni
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Akila Ramesh
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Dipak Roy
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Anant B Patel
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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Ebersole J, Rose G, Eid T, Behar K, Patrylo P. Altered hippocampal astroglial metabolism is associated with aging and preserved spatial learning and memory. Neurobiol Aging 2021; 102:188-199. [PMID: 33774381 DOI: 10.1016/j.neurobiolaging.2021.02.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022]
Abstract
An age-related decrease in hippocampal metabolism correlates with cognitive decline. Hippocampus-dependent learning and memory requires glutamatergic neurotransmission supported by glutamate-glutamine (GLU-GLN) cycling between neurons and astrocytes. We examined whether GLU-GLN cycling in hippocampal subregions (dentate gyrus and CA1) in Fischer 344 rats was altered with age and cognitive status. Hippocampal slices from young adult, aged cognitively-unimpaired (AU) and aged cognitively-impaired (AI) rats were incubated in artificial cerebrospinal fluid (aCSF) containing 1-13C-glucose to assess neural metabolism. Incorporation of 13C-glucose into glutamate and glutamine, measured by mass spectroscopy/liquid chromatography tandem mass spectroscopy, did not significantly differ between groups. However, when 13C-acetate, a preferential astrocytic metabolite, was used, a significant increase in 13C-labeled glutamate was observed in slices from AU rats. Taken together, the data suggest that resting state neural metabolism and GLU-GLN cycling may be preserved during aging when sufficient extracellular glucose is available, but that enhanced astroglial metabolism can occur under resting state conditions. This may be an aging-related compensatory change to maintain hippocampus-dependent cognitive function.
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Affiliation(s)
- Jeremy Ebersole
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Gregory Rose
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Tore Eid
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; MRRC Neurometabolism Research Laboratory, Yale University School of Medicine, New Haven, CT, USA
| | - Peter Patrylo
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA.
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Svyatova A, Kozinenko VP, Chukanov NV, Burueva DB, Chekmenev EY, Chen YW, Hwang DW, Kovtunov KV, Koptyug IV. PHIP hyperpolarized [1- 13C]pyruvate and [1- 13C]acetate esters via PH-INEPT polarization transfer monitored by 13C NMR and MRI. Sci Rep 2021; 11:5646. [PMID: 33707497 PMCID: PMC7952547 DOI: 10.1038/s41598-021-85136-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 02/18/2021] [Indexed: 01/31/2023] Open
Abstract
Parahydrogen-induced polarization of 13C nuclei by side-arm hydrogenation (PHIP-SAH) for [1-13C]acetate and [1-13C]pyruvate esters with application of PH-INEPT-type pulse sequences for 1H to 13C polarization transfer is reported, and its efficiency is compared with that of polarization transfer based on magnetic field cycling (MFC). The pulse-sequence transfer approach may have its merits in some applications because the entire hyperpolarization procedure is implemented directly in an NMR or MRI instrument, whereas MFC requires a controlled field variation at low magnetic fields. Optimization of the PH-INEPT-type transfer sequences resulted in 13C polarization values of 0.66 ± 0.04% and 0.19 ± 0.02% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively, which is lower than the corresponding polarization levels obtained with MFC for 1H to 13C polarization transfer (3.95 ± 0.05% and 0.65 ± 0.05% for allyl [1-13C]pyruvate and ethyl [1-13C]acetate, respectively). Nevertheless, a significant 13C NMR signal enhancement with respect to thermal polarization allowed us to perform 13C MR imaging of both biologically relevant hyperpolarized molecules which can be used to produce useful contrast agents for the in vivo imaging applications.
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Affiliation(s)
- Alexandra Svyatova
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090 ,grid.418953.2Institute of Cytology and Genetics SB RAS, 10 Ac. Lavrentieva Ave., Novosibirsk, Russia 630090
| | - Vitaly P. Kozinenko
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Nikita V. Chukanov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Dudari B. Burueva
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Eduard Y. Chekmenev
- grid.254444.70000 0001 1456 7807Department of Chemistry, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201 USA ,grid.254444.70000 0001 1456 7807Integrative Biosciences, Wayne State University, Detroit, MI 48201 USA ,grid.4886.20000 0001 2192 9124Russian Academy of Sciences, Moscow, Russia 119991
| | - Yu-Wen Chen
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Dennis W. Hwang
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, 115 Taiwan (Republic of China)
| | - Kirill V. Kovtunov
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090 ,grid.4605.70000000121896553Novosibirsk State University, 2 Pirogova St., Novosibirsk, Russia 630090
| | - Igor V. Koptyug
- grid.419389.e0000 0001 2163 7228International Tomography Center SB RAS, 3A Institutskaya St., Novosibirsk, Russia 630090
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12
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Bahadur Patel A, Veeraiah P, Shameem M, Mahesh Kumar J, Saba K. Impaired GABAergic and glutamatergic neurometabolic activity in aged mice brain as measured by 1 H-[ 13 C]-NMR spectroscopy. FASEB J 2021; 35:e21321. [PMID: 33543543 DOI: 10.1096/fj.202001704rr] [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: 07/10/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 01/04/2023]
Abstract
Healthy aging is associated with a decline in cognitive function, and is a major risk factor for many neurodegenerative diseases. Although, there are several evidence that brain mitochondrial function is altered with aging its significance at the cellular level is elusive. In this study, we have investigated mitochondrial TCA cycle and neurotransmitter cycle fluxes associated with glutamatergic, GABAergic neurons and astroglia in the cerebral cortex and hippocampus of young (6 months) and aged (24 months) C57BL6 mice by using 1 H-[13 C]-NMR spectroscopy together with timed infusion of 13 C-labeled glucose and acetate. The ratio VCyc /VTCA was determined from a steady-state [2-13 C]acetate experiment. Metabolic fluxes were obtained by fitting a three-compartment metabolic model to 13 C turnover of amino acids from glucose. Levels of glutamate, aspartate and taurine were reduced in the cerebral cortex, while glutamine and choline were elevated in the hippocampus of aged mice. Interestingly, the rate of acetate oxidation increased in the cerebral cortex, while the flux of mitochondrial TCA cycle of glutamatergic neurons decreased in the cerebral cortex (P < .0001) and hippocampus (P = .025) of aged mice. The glutamate-glutamine neurotransmitter cycle flux was reduced in the cerebral cortex (P < .0001). The GABAergic TCA cycle flux was reduced in the cerebral cortex (P = .0008), while GABA-glutamine neurotransmitter cycling flux was also reduced in the cerebral cortex (P = .011) and hippocampus (P = .042) of aged brain. In conclusion, the reduction in excitatory and inhibitory neurotransmitter activity of glutamatergic and GABAergic neurons in the cerebral cortex and hippocampus correlates qualitatively with declined cognitive function in aged mice.
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Affiliation(s)
- Anant Bahadur Patel
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Pandichelvam Veeraiah
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Mohammad Shameem
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Jerald Mahesh Kumar
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Kamal Saba
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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13
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Sarawagi A, Soni ND, Patel AB. Glutamate and GABA Homeostasis and Neurometabolism in Major Depressive Disorder. Front Psychiatry 2021; 12:637863. [PMID: 33986699 PMCID: PMC8110820 DOI: 10.3389/fpsyt.2021.637863] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/09/2021] [Indexed: 12/12/2022] Open
Abstract
Major depressive disorder (MDD) is a leading cause of distress, disability, and suicides. As per the latest WHO report, MDD affects more than 260 million people worldwide. Despite decades of research, the underlying etiology of depression is not fully understood. Glutamate and γ-aminobutyric acid (GABA) are the major excitatory and inhibitory neurotransmitters, respectively, in the matured central nervous system. Imbalance in the levels of these neurotransmitters has been implicated in different neurological and psychiatric disorders including MDD. 1H nuclear magnetic resonance (NMR) spectroscopy is a powerful non-invasive method to study neurometabolites homeostasis in vivo. Additionally, 13C-NMR spectroscopy together with an intravenous administration of non-radioactive 13C-labeled glucose or acetate provides a measure of neural functions. In this review, we provide an overview of NMR-based measurements of glutamate and GABA homeostasis, neurometabolic activity, and neurotransmitter cycling in MDD. Finally, we highlight the impact of recent advancements in treatment strategies against a depressive disorder that target glutamate and GABA pathways in the brain.
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Affiliation(s)
- Ajay Sarawagi
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Narayan Datt Soni
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Anant Bahadur Patel
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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14
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Lewandowski SL, Cardone RL, Foster HR, Ho T, Potapenko E, Poudel C, VanDeusen HR, Sdao SM, Alves TC, Zhao X, Capozzi ME, de Souza AH, Jahan I, Thomas CJ, Nunemaker CS, Davis DB, Campbell JE, Kibbey RG, Merrins MJ. Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway. Cell Metab 2020; 32:736-750.e5. [PMID: 33147484 PMCID: PMC7685238 DOI: 10.1016/j.cmet.2020.10.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/30/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022]
Abstract
Pancreatic β cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies β cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of β cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of β cell function.
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Affiliation(s)
- Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Rebecca L Cardone
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Hannah R Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Thuong Ho
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Evgeniy Potapenko
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Chetan Poudel
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sophia M Sdao
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tiago C Alves
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Arnaldo H de Souza
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ishrat Jahan
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Craig J Thomas
- National Center for Advancing Translational Sciences, Rockville, MD 20850, USA
| | - Craig S Nunemaker
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Richard G Kibbey
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Department of Cellular & Molecular Physiology, Yale University, New Haven, CT 06520, USA.
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA.
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15
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Lanz B, Abaei A, Braissant O, Choi IY, Cudalbu C, Henry PG, Gruetter R, Kara F, Kantarci K, Lee P, Lutz NW, Marjańska M, Mlynárik V, Rasche V, Xin L, Valette J. Magnetic resonance spectroscopy in the rodent brain: Experts' consensus recommendations. NMR IN BIOMEDICINE 2020; 34:e4325. [PMID: 33565219 PMCID: PMC9429976 DOI: 10.1002/nbm.4325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/29/2020] [Accepted: 04/30/2020] [Indexed: 05/21/2023]
Abstract
In vivo MRS is a non-invasive measurement technique used not only in humans, but also in animal models using high-field magnets. MRS enables the measurement of metabolite concentrations as well as metabolic rates and their modifications in healthy animals and disease models. Such data open the way to a deeper understanding of the underlying biochemistry, related disturbances and mechanisms taking place during or prior to symptoms and tissue changes. In this work, we focus on the main preclinical 1H, 31P and 13C MRS approaches to study brain metabolism in rodent models, with the aim of providing general experts' consensus recommendations (animal models, anesthesia, data acquisition protocols). An overview of the main practical differences in preclinical compared with clinical MRS studies is presented, as well as the additional biochemical information that can be obtained in animal models in terms of metabolite concentrations and metabolic flux measurements. The properties of high-field preclinical MRS and the technical limitations are also described.
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Affiliation(s)
- Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Alireza Abaei
- Core Facility Small Animal Imaging, Ulm University, Ulm, Germany
| | - Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and University Hospital of Lausanne, Lausanne, Switzerland
| | - In-Young Choi
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, US
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Pierre-Gilles Henry
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, US
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Firat Kara
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, US
| | - Kejal Kantarci
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, US
| | - Phil Lee
- Department of Radiology, University of Kansas Medical Center, Kansas City, Kansas, US
| | - Norbert W Lutz
- CNRS, CRMBM, Aix-Marseille University, Marseille, France
| | - Małgorzata Marjańska
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, US
| | - Vladimír Mlynárik
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Volker Rasche
- Core Facility Small Animal Imaging, Ulm University, Ulm, Germany
| | - Lijing Xin
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Julien Valette
- Commissariat à l'Energie Atomique et aux Energies Alternatives, MIRCen, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, Université Paris-Sud, Université Paris-Saclay, UMR 9199, Fontenay-aux-Roses, France
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16
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Impaired neuronal and astroglial metabolic activity in chronic unpredictable mild stress model of depression: Reversal of behavioral and metabolic deficit with lanicemine. Neurochem Int 2020; 137:104750. [DOI: 10.1016/j.neuint.2020.104750] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/05/2020] [Accepted: 04/24/2020] [Indexed: 01/20/2023]
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17
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Lane AN, Higashi RM, Fan TWM. Metabolic reprogramming in tumors: Contributions of the tumor microenvironment. Genes Dis 2020; 7:185-198. [PMID: 32215288 PMCID: PMC7083762 DOI: 10.1016/j.gendis.2019.10.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/06/2019] [Accepted: 10/16/2019] [Indexed: 12/22/2022] Open
Abstract
The genetic alterations associated with cell transformation are in large measure expressed in the metabolic phenotype as cancer cells proliferate and change their local environment, and prepare for metastasis. Qualitatively, the fundamental biochemistry of cancer cells is generally the same as in the untransformed cells, but the cancer cells produce a local environment, the TME, that is hostile to the stromal cells, and compete for nutrients. In order to proliferate, cells need sufficient nutrients, either those that cannot be made by the cells themselves, or must be made from simpler precursors. However, in solid tumors, the nutrient supply is often limiting given the potential for rapid proliferation, and the poor quality of the vasculature. Thus, cancer cells may employ a variety of strategies to obtain nutrients for survival, growth and metastasis. Although much has been learned using established cell lines in standard culture conditions, it is becoming clear from in vivo metabolic studies that this can also be misleading, and which nutrients are used for energy production versus building blocks for synthesis of macromolecules can vary greatly from tumor to tumor, and even within the same tumor. Here we review the operation of metabolic networks, and how recent understanding of nutrient supply in the TME and utilization are being revealed using stable isotope tracers in vivo as well as in vitro.
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Key Words
- 2OG, 2-oxoglutarate
- ACO1,2, aconitase 1,2
- CP-MAS, Cross polarization Magic Angle Spinning
- Cancer metabolism
- DMEM, Dulbeccos Modified Eagles Medium
- ECAR, extracellular acidification rate
- ECM, extracellular matrix
- EMP, Embden-Meyerhof Pathway
- IDH1,2, isocitrate dehydrogenase 1,2 (NADP+dependent)
- IF, interstitial fluid
- ME, malic enzyme
- Metabolic flux
- Nutrient supply
- RPMI, Roswell Park Memorial Institute
- SIRM, Stable Isotope Resolved Metabolomics
- Stable isotope resolved metabolomics
- TIL, tumor infiltrating lymphocyte
- TIM/TPI, triose phosphate isomerase
- TME, Tumor Micro Environment
- Tumor microenvironment
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Affiliation(s)
- Andrew N. Lane
- Center for Environmental and Systems Biochemistry, Markey Cancer Center, Department of Toxicology and Cancer Biology, University of Kentucky, USA
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18
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Wijdeveld M, Nieuwdorp M, IJzerman R. The interaction between microbiome and host central nervous system: the gut-brain axis as a potential new therapeutic target in the treatment of obesity and cardiometabolic disease. Expert Opin Ther Targets 2020; 24:639-653. [PMID: 32441559 DOI: 10.1080/14728222.2020.1761958] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION The role of the intestinal microbiota in host cardiometabolic health and disease has gained significant attention over recent decades. Previous studies have shown effects on metabolic health through gut microbiota modulation; this suggests diverse interaction pathways that constitute the communication between gut microbiota and host central nervous system, the so-called gut-brain axis. AREAS COVERED This article provides an overview of the various mechanisms that may mediate the gut-brain axis. It places an emphasis on cardiometabolic health, including effects of short-chain fatty acids (SCFA), alterations in neurotransmitters and gut peptides and microbial effects on chronic inflammation and immune function. Moreover, this paper sheds light on whether these mechanisms afford therapeutic targets to promote metabolic health. To this end, a PubMed search with the terms 'gut microbiota,' 'obesity' and 'insulin sensitivity' was performed. EXPERT OPINION Many properties of the human gut microbiome are associated with the central regulation of appetite and metabolic status. Some of these relationships are causal and there are positive effects from certain intervention methods. Microbial manipulation may offer a means to prevent or treat obesity and associated co-morbidities. However, to establish direct causal relations between altered gut microbiota and metabolic disease, clinical intervention studies are necessary.
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Affiliation(s)
- Madelief Wijdeveld
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centers , Amsterdam, The Netherlands
| | - Max Nieuwdorp
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centers , Amsterdam, The Netherlands
| | - Richard IJzerman
- Department of Endocrinology, Amsterdam University Medical Centers , Amsterdam, The Netherlands
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19
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Singh C, Tran V, McCollum L, Bolok Y, Allan K, Yuan A, Hoppe G, Brunengraber H, Sears JE. Hyperoxia induces glutamine-fuelled anaplerosis in retinal Müller cells. Nat Commun 2020; 11:1277. [PMID: 32152301 PMCID: PMC7062830 DOI: 10.1038/s41467-020-15066-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 02/17/2020] [Indexed: 01/03/2023] Open
Abstract
Although supplemental oxygen is required to promote survival of severely premature infants, hyperoxia is simultaneously harmful to premature developing tissues such as in the retina. Here we report the effect of hyperoxia on central carbon metabolism in primary mouse Müller glial cells and a human Müller glia cell line (M10-M1 cells). We found decreased flux from glycolysis entering the tricarboxylic acid cycle in Müller cells accompanied by increased glutamine consumption in response to hyperoxia. In hyperoxia, anaplerotic catabolism of glutamine by Müller cells increased ammonium release two-fold. Hyperoxia induces glutamine-fueled anaplerosis that reverses basal Müller cell metabolism from production to consumption of glutamine. Prematurely born babies need extra oxygen to survive, but this can cause damage to the eyes and lead to infant blindness. Here the authors show that this hyperoxia changes the metabolism of Müller cells in the retina such that they use up, rather than produce, glutamine and secrete excess ammonium.
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Affiliation(s)
- Charandeep Singh
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Vincent Tran
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Leah McCollum
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Youstina Bolok
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Kristin Allan
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Molecular Medicine, Case Western Reserve School of Medicine Cleveland, Cleveland, OH, 44106, USA
| | - Alex Yuan
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - George Hoppe
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Henri Brunengraber
- Department of Nutrition, Case Western Reserve School of Medicine Cleveland, Cleveland, OH, 44106, USA
| | - Jonathan E Sears
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, 44195, USA. .,Cardiovascular and Metabolic Sciences, Cleveland Clinic, Cleveland, OH, 44195, USA.
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20
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Wilson DF, Matschinsky FM. Ethanol metabolism: The good, the bad, and the ugly. Med Hypotheses 2020; 140:109638. [PMID: 32113062 DOI: 10.1016/j.mehy.2020.109638] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/20/2022]
Abstract
Throughout the world, ethanol is both an important commercial commodity and a source of major medical and social problems. Ethanol readily passes through biological membranes and distributes throughout the body. It is oxidized, first to acetaldehyde and then to acetate, and finally by the citric acid cycle in virtually all tissues. The oxidation of ethanol is irreversible and unregulated, making the rate dependent only on local concentration and enzyme activity. This unregulated input of reducing equivalents increases reduction of both cytoplasmic and intramitochondrial NAD and, through the latter, cellular energy state {[ATP]/([ADP][Pi])}. In brain, this increase in energy state stimulates dopaminergic neural activity signalling reward and a sense of well being, while suppressing glutamatergic neural activity signalling anxiety and unease. These positive responses to ethanol ingestion are important to social alcohol consumption. Importantly, decreased free [AMP] decreases AMP-dependent protein kinase (AMPK) activity, an important regulator of cellular energy metabolism. Oxidation of substrates used for energy metabolism in the absence of ethanol is down regulated to accommodate the input from ethanol. In liver, chronic ethanol metabolism results in fatty liver and general metabolic dysfunction. In brain, transport of other oxidizable metabolites through the blood-brain barrier and the enzymes for their oxidation are both down regulated. For exposures of short duration, ethanol induced regulatory changes are rapid and reversible, recovering completely when the concentrations of ethanol and acetate fall again. Longer periods of ethanol exposure and associated chronic suppression of AMPK activity activates regulatory mechanisms, including gene expression, that operate over longer time scales, both in onset and reversal. If chronic alcohol consumption is abruptly ended, metabolism is no longer able to respond rapidly enough to compensate. Glutamatergic neural activity adapts to chronic dysregulation of glutamate metabolism and suppression of glutamatergic neural activity by increasing excitatory and decreasing inhibitory amino acid receptors. A point is reached (ethanol dependence) where withdrawal of ethanol results in significant metabolic energy depletion in neurons and other brain cells as well as hyperexcitation of the glutamatergic system. The extent and regional specificity of energy depletion in the brain, combined with hyperactivity of the glutamatergic neuronal system, largely determines the severity of withdrawal symptoms.
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Affiliation(s)
- David F Wilson
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Franz M Matschinsky
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
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21
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Rothman DL, de Graaf RA, Hyder F, Mason GF, Behar KL, De Feyter HM. In vivo 13 C and 1 H-[ 13 C] MRS studies of neuroenergetics and neurotransmitter cycling, applications to neurological and psychiatric disease and brain cancer. NMR IN BIOMEDICINE 2019; 32:e4172. [PMID: 31478594 DOI: 10.1002/nbm.4172] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 06/10/2023]
Abstract
In the last 25 years 13 C MRS has been established as the only noninvasive method for measuring glutamate neurotransmission and cell specific neuroenergetics. Although technically and experimentally challenging 13 C MRS has already provided important new information on the relationship between neuroenergetics and neuronal function, the high energy cost of brain function in the resting state and the role of altered neuroenergetics and neurotransmitter cycling in disease. In this paper we review the metabolic and neurotransmitter pathways that can be measured by 13 C MRS and key findings on the linkage between neuroenergetics, neurotransmitter cycling, and brain function. Applications of 13 C MRS to neurological and psychiatric disease as well as brain cancer are reviewed. Recent technological developments that may help to overcome spatial resolution and brain coverage limitations of 13 C MRS are discussed.
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Affiliation(s)
- Douglas L Rothman
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Departments of Radiology and Biomedical Imaging, and Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, P.O. Box 208043, New Haven, CT, USA
| | - Robin A de Graaf
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Fahmeed Hyder
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Biomedical Engineering, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F Mason
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henk M De Feyter
- Departments of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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22
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Kosten L, Chowdhury GMI, Mingote S, Staelens S, Rothman DL, Behar KL, Rayport S. Glutaminase activity in GLS1 Het mouse brain compared to putative pharmacological inhibition by ebselen using ex vivo MRS. Neurochem Int 2019; 129:104508. [PMID: 31326460 DOI: 10.1016/j.neuint.2019.104508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/28/2019] [Accepted: 07/18/2019] [Indexed: 01/13/2023]
Abstract
Glutaminase mediates the recycling of neurotransmitter glutamate, supporting most excitatory neurotransmission in the mammalian central nervous system. A constitutive heterozygous reduction in GLS1 engenders in mice a model of schizophrenia resilience and associated increases in Gln, reductions in Glu and activity-dependent attenuation of excitatory synaptic transmission. Hippocampal brain slices from GLS1 heterozygous mice metabolize less Gln to Glu. Whether glutaminase activity is diminished in the intact brain in GLS1 heterozygous mice has not been assessed, nor the regional impact. Moreover, it is not known whether pharmacological inhibition would mimic the genetic reduction. We addressed this using magnetic resonance spectroscopy to assess amino acid content and 13C-acetate loading to assess glutaminase activity, in multiple brain regions. Glutaminase activity was reduced significantly in the hippocampus of GLS1 heterozygous mice, while acute treatment with the putative glutaminase inhibitor ebselen did not impact glutaminase activity, but did significantly increase GABA. This approach identifies a molecular imaging strategy for testing target engagement by comparing genetic and pharmacological inhibition, across brain regions.
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Affiliation(s)
- Lauren Kosten
- Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Golam M I Chowdhury
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, USA
| | - Susana Mingote
- Department of Psychiatry, Columbia University, USA; Department of Molecular Therapeutics, NYS Psychiatric Institute, USA; Neuroscience, Advanced Science Research Center at the Graduate Center of the City University of New York, USA
| | - Steven Staelens
- Molecular Imaging Center Antwerp, University of Antwerp, Antwerp, Belgium
| | - Douglas L Rothman
- Department of Radiology & Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, USA.
| | - Stephen Rayport
- Department of Psychiatry, Columbia University, USA; Department of Molecular Therapeutics, NYS Psychiatric Institute, USA.
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23
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Jakkamsetti V, Marin-Valencia I, Ma Q, Good LB, Terrill T, Rajasekaran K, Pichumani K, Khemtong C, Hooshyar MA, Sundarrajan C, Patel MS, Bachoo RM, Malloy CR, Pascual JM. Brain metabolism modulates neuronal excitability in a mouse model of pyruvate dehydrogenase deficiency. Sci Transl Med 2019; 11:eaan0457. [PMID: 30787166 PMCID: PMC6637765 DOI: 10.1126/scitranslmed.aan0457] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 09/25/2018] [Accepted: 01/31/2019] [Indexed: 12/25/2022]
Abstract
Glucose is the ultimate substrate for most brain activities that use carbon, including synthesis of the neurotransmitters glutamate and γ-aminobutyric acid via mitochondrial tricarboxylic acid (TCA) cycle. Brain metabolism and neuronal excitability are thus interdependent. However, the principles that govern their relationship are not always intuitive because heritable defects of brain glucose metabolism are associated with the paradoxical coexistence, in the same individual, of episodic neuronal hyperexcitation (seizures) with reduced basal cerebral electrical activity. One such prototypic disorder is pyruvate dehydrogenase (PDH) deficiency (PDHD). PDH is central to metabolism because it steers most of the glucose-derived flux into the TCA cycle. To better understand the pathophysiology of PDHD, we generated mice with brain-specific reduced PDH activity that paralleled salient human disease features, including cerebral hypotrophy, decreased amplitude electroencephalogram (EEG), and epilepsy. The mice exhibited reductions in cerebral TCA cycle flux, glutamate content, spontaneous, and electrically evoked in vivo cortical field potentials and gamma EEG oscillation amplitude. Episodic decreases in gamma oscillations preceded most epileptiform discharges, facilitating their prediction. Fast-spiking neuron excitability was decreased in brain slices, contributing to in vivo action potential burst prolongation after whisker pad stimulation. These features were partially reversed after systemic administration of acetate, which augmented cerebral TCA cycle flux, glutamate-dependent synaptic transmission, inhibition and gamma oscillations, and reduced epileptiform discharge duration. Thus, our results suggest that dysfunctional excitability in PDHD is consequent to reduced oxidative flux, which leads to decreased neuronal activation and impaired inhibition, and can be mitigated by an alternative metabolic substrate.
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Affiliation(s)
- Vikram Jakkamsetti
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Isaac Marin-Valencia
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, NY 10065, USA
| | - Qian Ma
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Levi B Good
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tyler Terrill
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Karthik Rajasekaran
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kumar Pichumani
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - M Ali Hooshyar
- Department of Mathematical Sciences, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Chandrasekhar Sundarrajan
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mulchand S Patel
- Department of Biochemistry, SUNY Buffalo, Buffalo, NY 14203, USA
| | - Robert M Bachoo
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Juan M Pascual
- Rare Brain Disorders Program, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Eugene McDermott Center for Human Growth & Development / Center for Human Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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24
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Rothman DL, Dienel GA. Development of a Model to Test Whether Glycogenolysis Can Support Astrocytic Energy Demands of Na +, K +-ATPase and Glutamate-Glutamine Cycling, Sparing an Equivalent Amount of Glucose for Neurons. ADVANCES IN NEUROBIOLOGY 2019; 23:385-433. [PMID: 31667817 DOI: 10.1007/978-3-030-27480-1_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recent studies of glycogen in brain have suggested a much more important role in brain energy metabolism and function than previously recognized, including findings of much higher than previously recognized concentrations, consumption at substantial rates compared with utilization of blood-borne glucose, and involvement in ion pumping and in neurotransmission and memory. However, it remains unclear how glycogenolysis is coupled to neuronal activity and provides support for neuronal as well as astroglial function. At present, quantitative aspects of glycogenolysis in brain functions are very difficult to assess due to its metabolic lability, heterogeneous distributions within and among cells, and extreme sensitivity to physiological stimuli. To begin to address this problem, the present study develops a model based on pathway fluxes, mass balance, and literature relevant to functions and turnover of pathways that intersect with glycogen mobilization. A series of equations is developed to describe the stoichiometric relationships between net glycogen consumption that is predominantly in astrocytes with the rate of the glutamate-glutamine cycle, rates of astrocytic and neuronal glycolytic and oxidative metabolism, and the energetics of sodium/potassium pumping in astrocytes and neurons during brain activation. Literature supporting the assumptions of the model is discussed in detail. The overall conclusion is that astrocyte glycogen metabolism is primarily coupled to neuronal function via fueling glycolytically pumping of Na+ and K+ and sparing glucose for neuronal oxidation, as opposed to previous proposals of coupling neurotransmission via glutamate transport, lactate shuttling, and neuronal oxidation of lactate.
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Affiliation(s)
- Douglas L Rothman
- Magnetic Resonance Research Center and Department of Radiology, Yale University, New Haven, CT, USA.
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.,Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, USA
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25
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Lane AN, Higashi RM, Fan TWM. NMR and MS-based Stable Isotope-Resolved Metabolomics and Applications in Cancer Metabolism. Trends Analyt Chem 2018; 120. [PMID: 32523238 DOI: 10.1016/j.trac.2018.11.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
There is considerable interest in defining metabolic reprogramming in human diseases, which is recognized as a hallmark of human cancer. Although radiotracers have a long history in specific metabolic studies, stable isotope-enriched precursors coupled with modern high resolution mass spectrometry and NMR spectroscopy have enabled systematic mapping of metabolic networks and fluxes in cells, tissues and living organisms including humans. These analytical platforms are high in information content, are complementary and cross-validating in terms of compound identification, quantification, and isotope labeling pattern analysis of a large number of metabolites simultaneously. Furthermore, new developments in chemoselective derivatization and in vivo spectroscopy enable tracking of labile/low abundance metabolites and metabolic kinetics in real-time. Here we review developments in Stable Isotope Resolved Metabolomics (SIRM) and recent applications in cancer metabolism using a wide variety of stable isotope tracers that probe both broad and specific aspects of cancer metabolism required for proliferation and survival.
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Affiliation(s)
- Andrew N Lane
- Center for Environmental and Systems Biochemistry, Dept. Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, 789 S. Limestone St., Lexington, KY 40536 USA
| | - Richard M Higashi
- Center for Environmental and Systems Biochemistry, Dept. Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, 789 S. Limestone St., Lexington, KY 40536 USA
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, Dept. Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky, 789 S. Limestone St., Lexington, KY 40536 USA
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26
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Lai M, Lanz B, Poitry-Yamate C, Romero JF, Berset CM, Cudalbu C, Gruetter R. In vivo 13C MRS in the mouse brain at 14.1 Tesla and metabolic flux quantification under infusion of [1,6- 13C 2]glucose. J Cereb Blood Flow Metab 2018; 38:1701-1714. [PMID: 29047296 PMCID: PMC6168901 DOI: 10.1177/0271678x17734101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In vivo 13C magnetic resonance spectroscopy (MRS) enables the investigation of cerebral metabolic compartmentation while, e.g. infusing 13C-labeled glucose. Metabolic flux analysis of 13C turnover previously yielded quantitative information of glutamate and glutamine metabolism in humans and rats, while the application to in vivo mouse brain remains exceedingly challenging. In the present study, 13C direct detection at 14.1 T provided highly resolved in vivo spectra of the mouse brain while infusing [1,6-13C2]glucose for up to 5 h. 13C incorporation to glutamate and glutamine C4, C3, and C2 and aspartate C3 were detected dynamically and fitted to a two-compartment model: flux estimation of neuron-glial metabolism included tricarboxylic acid cycle (TCA) flux in astrocytes (Vg = 0.16 ± 0.03 µmol/g/min) and neurons (VTCAn = 0.56 ± 0.03 µmol/g/min), pyruvate carboxylase activity (VPC = 0.041 ± 0.003 µmol/g/min) and neurotransmission rate (VNT = 0.084 ± 0.008 µmol/g/min), resulting in a cerebral metabolic rate of glucose (CMRglc) of 0.38 ± 0.02 µmol/g/min, in excellent agreement with that determined with concomitant 18F-fluorodeoxyglucose positron emission tomography (18FDG PET).We conclude that modeling of neuron-glial metabolism in vivo is accessible in the mouse brain from 13C direct detection with an unprecedented spatial resolution under [1,6-13C2]glucose infusion.
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Affiliation(s)
- Marta Lai
- 1 Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Bernard Lanz
- 1 Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Carole Poitry-Yamate
- 2 Center for Biomedical Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jackeline F Romero
- 2 Center for Biomedical Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Corina M Berset
- 2 Center for Biomedical Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Cristina Cudalbu
- 2 Center for Biomedical Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rolf Gruetter
- 1 Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,2 Center for Biomedical Imaging, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,3 Department of Radiology, University of Geneva, Geneva, Switzerland.,4 Department of Radiology, University of Lausanne, Lausanne, Switzerland
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27
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Mishra PK, Kumar A, Behar KL, Patel AB. Subanesthetic ketamine reverses neuronal and astroglial metabolic activity deficits in a social defeat model of depression. J Neurochem 2018; 146:722-734. [PMID: 29964293 DOI: 10.1111/jnc.14544] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 06/15/2018] [Accepted: 06/25/2018] [Indexed: 12/12/2022]
Abstract
Depression is one of the most debilitating neuropsychiatric disorders. Most of the current antidepressants have long remission time and low recovery rate. This study explores the impact of ketamine on neuronal and astroglial metabolic activity in prefrontal cortex in a social defeat (SD) model of depression. C57BL/6 mice were subjected to a social defeat paradigm for 5 min a day for 10 consecutive days. Ketamine (10 mg/kg, intraperitoneal) was administered to mice for two consecutive days following the last defeat stress. Mice were infused with [1,6-13 C2 ]glucose or [2-13 C]acetate to assess neuronal and astroglial metabolic activity, respectively, together with proton-observed carbon-edited nuclear magnetic resonance spectroscopy in prefrontal cortex tissue extract. The 13 C labeling of amino acids from glucose and acetate was decreased in SD mice. Ketamine treatment in SD mice restored sucrose preference, social interaction and immobility time to control values. Acute subanesthetic ketamine restored the 13 C labeling of brain amino acids from glucose as well as acetate in SD mice to the respective control values, suggesting that rates of neuronal and astroglial tricarboxylic acid (TCA) cycle and neurotransmitter cycling were re-established to normal levels. The finding of improved energy metabolism in SD mice suggests that fast anti-depressant action of ketamine is linked with improved neurotransmitter cycling.
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Affiliation(s)
- Pravin K Mishra
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Arvind Kumar
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Kevin L Behar
- Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Anant B Patel
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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28
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Patel AB, Tiwari V, Veeraiah P, Saba K. Increased astroglial activity and reduced neuronal function across brain in AβPP-PS1 mouse model of Alzheimer's disease. J Cereb Blood Flow Metab 2018; 38:1213-1226. [PMID: 28585882 PMCID: PMC6434450 DOI: 10.1177/0271678x17709463] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease associated with progressive loss of cognitive function, personality, and behavior. The present study evaluates neuronal and astroglial metabolic activity, and neurotransmitter cycle fluxes in AβPP-PS1 mouse model of AD by using 1H-[13C]-nuclear magnetic resonance (NMR) spectroscopy together with an infusion of either [1,6-13C2]glucose or [2-13C]acetate. The levels of N-acetyl-aspartate (NAA) and glutamate were found to be decreased in the cerebral cortex and hippocampus in AβPP-PS1 mice, when compared with wild type controls. The cerebral metabolic rate of acetate oxidation was increased in the hippocampus and cerebral cortex of AβPP-PS1 mice suggesting enhanced astroglial activity in AD. AβPP-PS1 mice exhibit severe reduction in glutamatergic and gamma-amino butyric acid (GABA)ergic neuronal metabolic activity and neurotransmitter cycling fluxes in the hippocampus, cerebral cortex, and striatum as compared with controls. These data suggest that metabolic activity of excitatory and inhibitory neurons is compromised across brain in AβPP-PS1 mouse model of AD.
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Affiliation(s)
- Anant B Patel
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Vivek Tiwari
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Kamal Saba
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
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29
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Dehghani M, Kunz N, Lanz B, Yoshihara HAI, Gruetter R. Diffusion-weighted MRS of acetate in the rat brain. NMR IN BIOMEDICINE 2017; 30:e3768. [PMID: 28796319 DOI: 10.1002/nbm.3768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 05/04/2017] [Accepted: 05/31/2017] [Indexed: 06/07/2023]
Abstract
Acetate has been proposed as an astrocyte-specific energy substrate for metabolic studies in the brain. The determination of the relative contribution of the intracellular and extracellular compartments to the acetate signal using diffusion-weighted magnetic resonance spectroscopy can provide an insight into the cellular environment and distribution volume of acetate in the brain. In the present study, localized 1 H nuclear magnetic resonance (NMR) spectroscopy employing a diffusion-weighted stimulated echo acquisition mode (STEAM) sequence at an ultra-high magnetic field (14.1 T) was used to investigate the diffusivity characteristics of acetate and N-acetylaspartate (NAA) in the rat brain in vivo during prolonged acetate infusion. The persistence of the acetate resonance in 1 H spectra acquired at very large diffusion weighting indicated restricted diffusion of acetate and was attributed to intracellular spaces. However, the significantly greater diffusion of acetate relative to NAA suggests that a substantial fraction of acetate is located in the extracellular space of the brain. Assuming an even distribution for acetate in intracellular and extracellular spaces, the diffusion properties of acetate yielded a smaller volume of distribution for acetate relative to water and glucose in the rat brain.
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Affiliation(s)
- Masoumeh Dehghani
- Laboratoire d'imagerie fonctionnelle et métabolique (LIFMET), École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Nicolas Kunz
- Centre d'Imagerie BioMédicale (CIBM)-AIT, École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bernard Lanz
- Laboratoire d'imagerie fonctionnelle et métabolique (LIFMET), École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Hikari A I Yoshihara
- Service de Cardiologie, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Rolf Gruetter
- Laboratoire d'imagerie fonctionnelle et métabolique (LIFMET), École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Centre d'Imagerie BioMédicale (CIBM), École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Department of Radiology, Université de Lausanne (UNIL), Lausanne, Switzerland
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30
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Sonnay S, Gruetter R, Duarte JMN. How Energy Metabolism Supports Cerebral Function: Insights from 13C Magnetic Resonance Studies In vivo. Front Neurosci 2017; 11:288. [PMID: 28603480 PMCID: PMC5445183 DOI: 10.3389/fnins.2017.00288] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/04/2017] [Indexed: 12/25/2022] Open
Abstract
Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS), several groups have worked on assessing cerebral metabolism in vivo. In this context, 1H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. 1H-[13C] MRS, i.e., indirect detection of signals from 13C-coupled 1H, together with infusion of 13C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of 13C isotopomers), the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct 13C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here, we review state-of-the-art MR methods to study brain function and metabolism in vivo, and their contribution to the current understanding of how astrocytic energy metabolism supports glutamatergic activity and cerebral function. In this context, recent data suggests that astrocytic metabolism has been underestimated. Namely, the rate of oxidative metabolism in astrocytes is about half of that in neurons, and it can increase as much as the rate of neuronal metabolism in response to sensory stimulation.
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Affiliation(s)
- Sarah Sonnay
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de LausanneLausanne, Switzerland
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de LausanneLausanne, Switzerland.,Department of Radiology, University of LausanneLausanne, Switzerland.,Department of Radiology, University of GenevaGeneva, Switzerland
| | - João M N Duarte
- Laboratory for Functional and Metabolic Imaging, École Polytechnique Fédérale de LausanneLausanne, Switzerland
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31
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Andersen JV, McNair LF, Schousboe A, Waagepetersen HS. Specificity of exogenous acetate and glutamate as astrocyte substrates examined in acute brain slices from female mice using methionine sulfoximine (MSO) to inhibit glutamine synthesis. J Neurosci Res 2017; 95:2207-2216. [DOI: 10.1002/jnr.24038] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/05/2017] [Accepted: 01/26/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Jens Velde Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; DK-2100 Copenhagen Denmark
| | - Laura Frendrup McNair
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; DK-2100 Copenhagen Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; DK-2100 Copenhagen Denmark
| | - Helle Sønderby Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences; University of Copenhagen; DK-2100 Copenhagen Denmark
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Rowlands BD, Klugmann M, Rae CD. Acetate metabolism does not reflect astrocytic activity, contributes directly to GABA synthesis, and is increased by silent information regulator 1 activation. J Neurochem 2017; 140:903-918. [PMID: 27925207 DOI: 10.1111/jnc.13916] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 12/26/2022]
Abstract
[13 C]Acetate is known to label metabolites preferentially in astrocytes rather than neurons and it has consequently been used as a marker for astrocytic activity. Recent discoveries suggest that control of acetate metabolism and its contributions to the synthesis of metabolites in brain is not as simple as first thought. Here, using a Guinea pig brain cortical tissue slice model metabolizing [1-13 C]D-glucose and [1,2-13 C]acetate, we investigated control of acetate metabolism and the degree to which it reflects astrocytic activity. Using a range of [1,2-13 C]acetate concentrations, we found that acetate is a poor substrate for metabolism and will inhibit metabolism of itself and of glucose at concentrations in excess of 2 mmol/L. By activating astrocytes using potassium depolarization, we found that use of [1,2-13 C]acetate to synthesize glutamine decreases significantly under these conditions showing that acetate metabolism does not necessarily reflect astrocytic activity. By blocking synthesis of glutamine using methionine sulfoximine, we found that significant amount of [1,2-13 C]acetate are still incorporated into GABA and its metabolic precursors in neurons, with around 30% of the GABA synthesized from [1,2-13 C]acetate likely to be made directly in neurons rather than from glutamine supplied by astrocytes. Finally, to test whether activity of the acetate metabolizing enzyme acetyl-CoA synthetase is under acetylation control in the brain, we incubated slices with the AceCS1 deacetylase silent information regulator 1 (SIRT1) activator SRT 1720 and showed consequential increased incorporation of [1,2-13 C]acetate into metabolites. Taken together, these data show that acetate metabolism is not directly nor exclusively related to astrocytic metabolic activity, that use of acetate is related to enzyme acetylation and that acetate is directly metabolized to a significant degree in GABAergic neurons. Changes in acetate metabolism should be interpreted as modulation of metabolism through changes in cellular energetic status via altered enzyme acetylation levels rather than simply as an adjustment of glial-neuronal metabolic activity.
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Affiliation(s)
- Benjamin D Rowlands
- Neuroscience Research Australia, Randwick, NSW, Australia.,Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Neuroscience Research Australia, Randwick, NSW, Australia.,Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Caroline D Rae
- Neuroscience Research Australia, Randwick, NSW, Australia.,School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia
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Lai M, Gruetter R, Lanz B. Progress towards in vivo brain 13C-MRS in mice: Metabolic flux analysis in small tissue volumes. Anal Biochem 2017; 529:229-244. [PMID: 28119064 DOI: 10.1016/j.ab.2017.01.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 01/08/2023]
Abstract
The combination of dynamic 13C MRS data under infusion of 13C-labelled substrates and compartmental models of cerebral metabolism enabled in vivo measurement of metabolic fluxes with a quantitative and distinct determination of cellular-specific activities. The non-invasive nature and the chemical specificity of the 13C dynamic data obtained in those tracer experiments makes it an attractive approach offering unique insights into cerebral metabolism. Genetically engineered mice present a wealth of disease models particularly interesting for the neuroscience community. Nevertheless, in vivo13C NMR studies of the mouse brain are only recently appearing in the field due to the numerous challenges linked to the small mouse brain volume and the difficulty to follow the mouse physiological parameters within the NMR system during the infusion experiment. This review will present the progresses in the quest for a higher in vivo13C signal-to-noise ratio up to the present state of the art techniques, which made it feasible to assess glucose metabolism in different regions of the mouse brain. We describe how experimental results were integrated into suitable compartmental models and how a deep understanding of cerebral metabolism depends on the reliable detection of 13C in the different molecules and carbon positions.
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Affiliation(s)
- Marta Lai
- Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Department of Radiology, University of Geneva, 1205 Geneva, Switzerland; Department of Radiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom
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Patel AB, Lai JCK, Chowdhury GIM, Rothman DL, Behar KL. Comparison of Glutamate Turnover in Nerve Terminals and Brain Tissue During [1,6- 13C 2]Glucose Metabolism in Anesthetized Rats. Neurochem Res 2016; 42:173-190. [PMID: 28025798 DOI: 10.1007/s11064-016-2103-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/06/2016] [Accepted: 11/08/2016] [Indexed: 01/05/2023]
Abstract
The 13C turnover of neurotransmitter amino acids (glutamate, GABA and aspartate) were determined from extracts of forebrain nerve terminals and brain homogenate, and fronto-parietal cortex from anesthetized rats undergoing timed infusions of [1,6-13C2]glucose or [2-13C]acetate. Nerve terminal 13C fractional labeling of glutamate and aspartate was lower than those in whole cortical tissue at all times measured (up to 120 min), suggesting either the presence of a constant dilution flux from an unlabeled substrate or an unlabeled (effectively non-communicating on the measurement timescale) glutamate pool in the nerve terminals. Half times of 13C labeling from [1,6-13C2]glucose, as estimated by least squares exponential fitting to the time course data, were longer for nerve terminals (GluC4, 21.8 min; GABAC2 21.0 min) compared to cortical tissue (GluC4, 12.4 min; GABAC2, 14.5 min), except for AspC3, which was similar (26.5 vs. 27.0 min). The slower turnover of glutamate in the nerve terminals (but not GABA) compared to the cortex may reflect selective effects of anesthesia on activity-dependent glucose use, which might be more pronounced in the terminals. The 13C labeling ratio for glutamate-C4 from [2-13C]acetate over that of 13C-glucose was twice as large in nerve terminals compared to cortex, suggesting that astroglial glutamine under the 13C glucose infusion was the likely source of much of the nerve terminal dilution. The net replenishment of most of the nerve terminal amino acid pools occurs directly via trafficking of astroglial glutamine.
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Affiliation(s)
- Anant B Patel
- Department of Diagnostic Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, 06520, USA. .,CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500007, India.
| | - James C K Lai
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID, 83209, USA
| | - Golam I M Chowdhury
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, PO Box 208043, New Haven, CT, 06520, USA
| | - Douglas L Rothman
- Department of Diagnostic Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Kevin L Behar
- Department of Psychiatry, Magnetic Resonance Research Center, Yale University School of Medicine, 300 Cedar Street, PO Box 208043, New Haven, CT, 06520, USA.
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McNair LF, Kornfelt R, Walls AB, Andersen JV, Aldana BI, Nissen JD, Schousboe A, Waagepetersen HS. Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates. Neurochem Res 2016; 42:810-826. [DOI: 10.1007/s11064-016-2116-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 11/11/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022]
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Hyperpolarized MRS: New tool to study real-time brain function and metabolism. Anal Biochem 2016; 529:270-277. [PMID: 27665679 DOI: 10.1016/j.ab.2016.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/31/2016] [Accepted: 09/21/2016] [Indexed: 11/23/2022]
Abstract
The advent of dissolution dynamic nuclear polarization (DNP) led to the emergence of a new kind of magnetic resonance (MR) measurements providing the opportunity to probe metabolism in vivo in real time. It has been shown that, following the injection of hyperpolarized substrates prepared using dissolution DNP, specific metabolic bioprobes that can be used to differentiate between healthy and pathological tissue in preclinical and clinical studies can be readily detected by MR thanks to the tremendous signal enhancement. The present article aims at reviewing the studies of cerebral function and metabolism based on the use of hyperpolarized MR. The constraints and future opportunities that this technology could offer are discussed.
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Tsai SF, Chen PC, Calkins MJ, Wu SY, Kuo YM. Exercise Counteracts Aging-Related Memory Impairment: A Potential Role for the Astrocytic Metabolic Shuttle. Front Aging Neurosci 2016; 8:57. [PMID: 27047373 PMCID: PMC4801859 DOI: 10.3389/fnagi.2016.00057] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/08/2016] [Indexed: 01/19/2023] Open
Abstract
Age-related cognitive impairment has become one of the most common health threats in many countries. The biological substrate of cognition is the interconnection of neurons to form complex information processing networks. Experience-based alterations in the activities of these information processing networks lead to neuroadaptation, which is physically represented at the cellular level as synaptic plasticity. Although synaptic plasticity is known to be affected by aging, the underlying molecular mechanisms are not well described. Astrocytes, a glial cell type that is infrequently investigated in cognitive science, have emerged as energy suppliers which are necessary for meeting the abundant energy demand resulting from glutamatergic synaptic activity. Moreover, the concerted action of an astrocyte-neuron metabolic shuttle is essential for cognitive function; whereas, energetic incoordination between astrocytes and neurons may contribute to cognitive impairment. Whether altered function of the astrocyte-neuron metabolic shuttle links aging to reduced synaptic plasticity is unexplored. However, accumulated evidence documents significant beneficial effects of long-term, regular exercise on cognition and synaptic plasticity. Furthermore, exercise increases the effectiveness of astrocyte-neuron metabolic shuttle by upregulation of astrocytic lactate transporter levels. This review summarizes previous findings related to the neuronal activity-dependent astrocyte-neuron metabolic shuttle. Moreover, we discuss how aging and exercise may shape the astrocyte-neuron metabolic shuttle in cognition-associated brain areas.
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Affiliation(s)
- Sheng-Feng Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University Tainan, Taiwan
| | - Pei-Chun Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan; Department of Physiology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Marcus J Calkins
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University Tainan, Taiwan
| | - Shih-Ying Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University Tainan, Taiwan
| | - Yu-Min Kuo
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan; Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
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Okada M, Yanamoto K, Kagawa T, Yoshino K, Hosoi R, Abe K, Zhang MR, Inoue O. Kinetic study of benzyl [1-14C]acetate as a potential probe for astrocytic energy metabolism in the rat brain: Comparison with benzyl [2-14C]acetate. J Cereb Blood Flow Metab 2016; 36:442-50. [PMID: 26661153 PMCID: PMC4759666 DOI: 10.1177/0271678x15606144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 07/28/2015] [Indexed: 11/15/2022]
Abstract
Brain uptake of [(14)C]acetate has been reported to be a useful marker of astrocytic energy metabolism. In addition to uptake values, the rate of radiolabeled acetate washout from the brain appears to reflect CO2 exhaustion and oxygen consumption in astrocytes. We measured the time-radioactivity curves of benzyl [1-(14)C]acetate ([1-(14)C]BA), a lipophilic probe of [1-(14)C]acetate, and compared it with that of benzyl [2-(14)C]acetate ([2-(14)C]BA) in rat brains. The highest brain uptake was observed immediately after injecting either [1-(14)C]BA or [2-(14)C]BA, and both subsequently disappeared from the brain in a single-exponential manner. Estimated [1-(14)C]BA washout rates in the cerebral cortex and cerebellum were higher than those of [2-(14)C]BA. These results suggested that [1-(14)C]BA could be a useful probe for estimating the astrocytic oxidative metabolism. The [1-(14)C]BA washout rate in the cerebral cortex of immature rats was lower than that of mature rats. An autoradiographic study showed that the washout rates of [1-(14)C]BA from the rat brains of a lithium-pilocarpine-induced status epilepticus model were not significantly different from the values in control rat brains except for the medial septal nucleus. These results implied that the enhancement of amino acid turnover rate rather than astrocytic oxidative metabolism was increased in status epilepticus.
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Affiliation(s)
- Maki Okada
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Kazuhiko Yanamoto
- Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tomohiko Kagawa
- Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Keiko Yoshino
- Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Rie Hosoi
- Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kohji Abe
- Department of Molecular Imaging in Medicine, Osaka University Graduate School of Medicine, Suita, Japan Department of Drug Metabolism & Pharmacokinetics, Research Laboratory for Development, Shionogi & Co., Ltd., Toyonaka, Japan
| | - Ming-Rong Zhang
- Molecular Probe Program, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Osamu Inoue
- Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
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Mingote S, Masson J, Gellman C, Thomsen GM, Lin CS, Merker RJ, Gaisler-Salomon I, Wang Y, Ernst R, Hen R, Rayport S. Genetic Pharmacotherapy as an Early CNS Drug Development Strategy: Testing Glutaminase Inhibition for Schizophrenia Treatment in Adult Mice. Front Syst Neurosci 2016; 9:165. [PMID: 26778975 PMCID: PMC4705219 DOI: 10.3389/fnsys.2015.00165] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 11/12/2015] [Indexed: 01/23/2023] Open
Abstract
Genetic pharmacotherapy is an early drug development strategy for the identification of novel CNS targets in mouse models prior to the development of specific ligands. Here for the first time, we have implemented this strategy to address the potential therapeutic value of a glutamate-based pharmacotherapy for schizophrenia involving inhibition of the glutamate recycling enzyme phosphate-activated glutaminase. Mice constitutively heterozygous for GLS1, the gene encoding glutaminase, manifest a schizophrenia resilience phenotype, a key dimension of which is an attenuated locomotor response to propsychotic amphetamine challenge. If resilience is due to glutaminase deficiency in adulthood, then glutaminase inhibitors should have therapeutic potential. However, this has been difficult to test given the dearth of neuroactive glutaminase inhibitors. So, we used genetic pharmacotherapy to ask whether adult induction of GLS1 heterozygosity would attenuate amphetamine responsiveness. We generated conditional floxGLS1 mice and crossed them with global CAGERT2cre∕+ mice to produce GLS1 iHET mice, susceptible to tamoxifen induction of GLS1 heterozygosity. One month after tamoxifen treatment of adult GLS1 iHET mice, we found a 50% reduction in GLS1 allelic abundance and glutaminase mRNA levels in the brain. While GLS1 iHET mice showed some recombination prior to tamoxifen, there was no impact on mRNA levels. We then asked whether induction of GLS heterozygosity would attenuate the locomotor response to propsychotic amphetamine challenge. Before tamoxifen, control and GLS1 iHET mice did not differ in their response to amphetamine. One month after tamoxifen treatment, amphetamine-induced hyperlocomotion was blocked in GLS1 iHET mice. The block was largely maintained after 5 months. Thus, a genetically induced glutaminase reduction—mimicking pharmacological inhibition—strongly attenuated the response to a propsychotic challenge, suggesting that glutaminase may be a novel target for the pharmacotherapy of schizophrenia. These results demonstrate how genetic pharmacotherapy can be implemented to test a CNS target in advance of the development of specific neuroactive inhibitors. We discuss further the advantages, limitations, and feasibility of the wider application of genetic pharmacotherapy for neuropsychiatric drug development.
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Affiliation(s)
- Susana Mingote
- Department of Psychiatry, Columbia UniversityNew York, NY, USA; Department of Molecular Therapeutics, New York State Psychiatric InstituteNew York, NY, USA
| | - Justine Masson
- Department of Psychiatry, Columbia UniversityNew York, NY, USA; Centre de Psychiatrie et Neurosciences, Institut National de la Santé et de la Recherche Médicale UMR 894 and Université Paris DescartesParis, France
| | - Celia Gellman
- Department of Psychiatry, Columbia University New York, NY, USA
| | | | - Chyuan-Sheng Lin
- Department of Pathology and Cell Biology, Columbia University New York, NY, USA
| | - Robert J Merker
- Department of Integrative Neuroscience, New York State Psychiatric Institute New York, NY, USA
| | - Inna Gaisler-Salomon
- Department of Psychiatry, Columbia UniversityNew York, NY, USA; Psychobiology Labs, Department of Psychology, University of HaifaHaifa, Israel
| | - Yvonne Wang
- Department of Molecular Therapeutics, New York State Psychiatric Institute New York, NY, USA
| | - Rachel Ernst
- Department of Molecular Therapeutics, New York State Psychiatric Institute New York, NY, USA
| | - René Hen
- Department of Integrative Neuroscience, New York State Psychiatric InstituteNew York, NY, USA; Departments of Neuroscience and Pharmacology, Columbia UniversityNew York, NY, USA
| | - Stephen Rayport
- Department of Psychiatry, Columbia UniversityNew York, NY, USA; Department of Molecular Therapeutics, New York State Psychiatric InstituteNew York, NY, USA
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Eid T, Gruenbaum SE, Dhaher R, Lee TSW, Zhou Y, Danbolt NC. The Glutamate-Glutamine Cycle in Epilepsy. ADVANCES IN NEUROBIOLOGY 2016; 13:351-400. [PMID: 27885637 DOI: 10.1007/978-3-319-45096-4_14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Epilepsy is a complex, multifactorial disease characterized by spontaneous recurrent seizures and an increased incidence of comorbid conditions such as anxiety, depression, cognitive dysfunction, and sudden unexpected death. About 70 million people worldwide are estimated to suffer from epilepsy, and up to one-third of all people with epilepsy are expected to be refractory to current medications. Development of more effective and specific antiepileptic interventions is therefore requisite. Perturbations in the brain's glutamate-glutamine cycle, such as increased extracellular levels of glutamate, loss of astroglial glutamine synthetase, and changes in glutaminase and glutamate dehydrogenase, are frequently encountered in patients with epilepsy. Hence, manipulations of discrete glutamate-glutamine cycle components may represent novel approaches to treat the disease. The goal of his review is to discuss some of the glutamate-glutamine cycle components that are altered in epilepsy, particularly neurotransmitters and metabolites, enzymes, amino acid transporters, and glutamate receptors. We will also review approaches that potentially could be used in humans to target the glutamate-glutamine cycle. Examples of such approaches are treatment with glutamate receptor blockers, glutamate scavenging, dietary intervention, and hypothermia.
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Affiliation(s)
- Tore Eid
- Department of Laboratory Medicine, Yale School of Medicine, 330 Cedar Street, 208035, New Haven, CT, 06520-8035, USA.
| | - Shaun E Gruenbaum
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Roni Dhaher
- Department of Laboratory Medicine, Yale School of Medicine, 330 Cedar Street, 208035, New Haven, CT, 06520-8035, USA
| | - Tih-Shih W Lee
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Yun Zhou
- Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Niels Christian Danbolt
- Department of Molecular Medicine, Institute for Basic Medical Sciences, University of Oslo, Oslo, Norway
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Integrated, Step-Wise, Mass-Isotopomeric Flux Analysis of the TCA Cycle. Cell Metab 2015; 22:936-47. [PMID: 26411341 PMCID: PMC4635072 DOI: 10.1016/j.cmet.2015.08.021] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/12/2015] [Accepted: 08/25/2015] [Indexed: 11/24/2022]
Abstract
Mass isotopomer multi-ordinate spectral analysis (MIMOSA) is a step-wise flux analysis platform to measure discrete glycolytic and mitochondrial metabolic rates. Importantly, direct citrate synthesis rates were obtained by deconvolving the mass spectra generated from [U-(13)C6]-D-glucose labeling for position-specific enrichments of mitochondrial acetyl-CoA, oxaloacetate, and citrate. Comprehensive steady-state and dynamic analyses of key metabolic rates (pyruvate dehydrogenase, β-oxidation, pyruvate carboxylase, isocitrate dehydrogenase, and PEP/pyruvate cycling) were calculated from the position-specific transfer of (13)C from sequential precursors to their products. Important limitations of previous techniques were identified. In INS-1 cells, citrate synthase rates correlated with both insulin secretion and oxygen consumption. Pyruvate carboxylase rates were substantially lower than previously reported but showed the highest fold change in response to glucose stimulation. In conclusion, MIMOSA measures key metabolic rates from the precursor/product position-specific transfer of (13)C-label between metabolites and has broad applicability to any glucose-oxidizing cell.
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Salnikov OG, Kovtunov KV, Koptyug IV. Production of Catalyst-Free Hyperpolarised Ethanol Aqueous Solution via Heterogeneous Hydrogenation with Parahydrogen. Sci Rep 2015; 5:13930. [PMID: 26349543 PMCID: PMC4642547 DOI: 10.1038/srep13930] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/12/2015] [Indexed: 01/02/2023] Open
Abstract
An experimental approach for the production of catalyst-free hyperpolarised ethanol solution in water via heterogeneous hydrogenation of vinyl acetate with parahydrogen and the subsequent hydrolysis of ethyl acetate was demonstrated. For an efficient hydrogenation, liquid vinyl acetate was transferred to the gas phase by parahydrogen bubbling and almost completely converted to ethyl acetate with Rh/TiO2 catalyst. Subsequent dissolution of ethyl acetate gas in water containing OH(-) ions led to the formation of catalyst- and organic solvent-free hyperpolarised ethanol and sodium acetate. These results represent the first demonstration of catalyst- and organic solvent-free hyperpolarised ethanol production achieved by heterogeneous hydrogenation of vinyl acetate vapour with parahydrogen and the subsequent ethyl acetate hydrolysis.
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Affiliation(s)
- Oleg G. Salnikov
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russia
| | - Kirill V. Kovtunov
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russia
| | - Igor V. Koptyug
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
- Novosibirsk State University, Pirogova St. 2, Novosibirsk, 630090, Russia
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Iversen P, Mouridsen K, Hansen MB, Jensen SB, Sørensen M, Bak LK, Waagepetersen HS, Schousboe A, Ott P, Vilstrup H, Keiding S, Gjedde A. Oxidative metabolism of astrocytes is not reduced in hepatic encephalopathy: a PET study with [(11)C]acetate in humans. Front Neurosci 2014; 8:353. [PMID: 25404890 PMCID: PMC4217371 DOI: 10.3389/fnins.2014.00353] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/14/2014] [Indexed: 12/31/2022] Open
Abstract
In patients with impaired liver function and hepatic encephalopathy (HE), consistent elevations of blood ammonia concentration suggest a crucial role in the pathogenesis of HE. Ammonia and acetate are metabolized in brain both primarily in astrocytes. Here, we used dynamic [(11)C]acetate PET of the brain to measure the contribution of astrocytes to the previously observed reduction of brain oxidative metabolism in patients with liver cirrhosis and HE, compared to patients with cirrhosis without HE, and to healthy subjects. We used a new kinetic model to estimate uptake from blood to astrocytes and astrocyte metabolism of [(11)C]acetate. No significant differences of the rate constant of oxidation of [(11)C]acetate (k 3) were found among the three groups of subjects. The net metabolic clearance of [(11)C]acetate from blood was lower in the group of patients with cirrhosis and HE than in the group of healthy subjects (P < 0.05), which we interpret to be an effect of reduced cerebral blood flow rather than a reflection of low [(11)C]acetate metabolism. We conclude that the characteristic decline of whole-brain oxidative metabolism in patients with cirrhosis with HE is not due to malfunction of oxidative metabolism in astrocytes. Thus, the observed decline of brain oxidative metabolism implicates changes of neurons and their energy turnover in patients with HE.
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Affiliation(s)
- Peter Iversen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital Aarhus, Denmark
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience, Aarhus University Aarhus, Denmark
| | - Mikkel B Hansen
- Center of Functionally Integrative Neuroscience, Aarhus University Aarhus, Denmark
| | - Svend B Jensen
- Department of Nuclear Medicine, Aalborg University Hospital Aalborg, Denmark ; Department of Chemistry and Biochemistry, Aalborg University Aalborg, Denmark
| | - Michael Sørensen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital Aarhus, Denmark ; Department of Hepatology and Gastroenterology, Aarhus University Hospital Aarhus, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
| | - Peter Ott
- Department of Hepatology and Gastroenterology, Aarhus University Hospital Aarhus, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital Aarhus, Denmark
| | - Susanne Keiding
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital Aarhus, Denmark ; Department of Hepatology and Gastroenterology, Aarhus University Hospital Aarhus, Denmark ; Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
| | - Albert Gjedde
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital Aarhus, Denmark ; Center of Functionally Integrative Neuroscience, Aarhus University Aarhus, Denmark ; Brain Research and Integrative Neuroscience Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
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Characterization of cerebral glutamine uptake from blood in the mouse brain: implications for metabolic modeling of 13C NMR data. J Cereb Blood Flow Metab 2014; 34:1666-72. [PMID: 25074745 PMCID: PMC4269725 DOI: 10.1038/jcbfm.2014.129] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 06/10/2014] [Accepted: 06/30/2014] [Indexed: 01/20/2023]
Abstract
(13)C Nuclear Magnetic Resonance (NMR) studies of rodent and human brain using [1-(13)C]/[1,6-(13)C2]glucose as labeled substrate have consistently found a lower enrichment (∼25% to 30%) of glutamine-C4 compared with glutamate-C4 at isotopic steady state. The source of this isotope dilution has not been established experimentally but may potentially arise either from blood/brain exchange of glutamine or from metabolism of unlabeled substrates in astrocytes, where glutamine synthesis occurs. In this study, the contribution of the former was evaluated ex vivo using (1)H-[(13)C]-NMR spectroscopy together with intravenous infusion of [U-(13)C5]glutamine for 3, 15, 30, and 60 minutes in mice. (13)C labeling of brain glutamine was found to be saturated at plasma glutamine levels >1.0 mmol/L. Fitting a blood-astrocyte-neuron metabolic model to the (13)C enrichment time courses of glutamate and glutamine yielded the value of glutamine influx, VGln(in), 0.036±0.002 μmol/g per minute for plasma glutamine of 1.8 mmol/L. For physiologic plasma glutamine level (∼0.6 mmol/L), VGln(in) would be ∼0.010 μmol/g per minute, which corresponds to ∼6% of the glutamine synthesis rate and rises to ∼11% for saturating blood glutamine concentrations. Thus, glutamine influx from blood contributes at most ∼20% to the dilution of astroglial glutamine-C4 consistently seen in metabolic studies using [1-(13)C]glucose.
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Fried NT, Moffat C, Seifert EL, Oshinsky ML. Functional mitochondrial analysis in acute brain sections from adult rats reveals mitochondrial dysfunction in a rat model of migraine. Am J Physiol Cell Physiol 2014; 307:C1017-30. [PMID: 25252946 DOI: 10.1152/ajpcell.00332.2013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondrial dysfunction has been implicated in many neurological disorders that only develop or are much more severe in adults, yet no methodology exists that allows for medium-throughput functional mitochondrial analysis of brain sections from adult animals. We developed a technique for quantifying mitochondrial respiration in acutely isolated adult rat brain sections with the Seahorse XF Analyzer. Evaluating a range of conditions made quantifying mitochondrial function from acutely derived adult brain sections from the cortex, cerebellum, and trigeminal nucleus caudalis possible. Optimization of this technique demonstrated that the ideal section size was 1 mm wide. We found that sectioning brains at physiological temperatures was necessary for consistent metabolic analysis of trigeminal nucleus caudalis sections. Oxygen consumption in these sections was highly coupled to ATP synthesis, had robust spare respiratory capacities, and had limited nonmitochondrial respiration, all indicative of healthy tissue. We demonstrate the effectiveness of this technique by identifying a decreased spare respiratory capacity in the trigeminal nucleus caudalis of a rat model of chronic migraine, a neurological disorder that has been associated with mitochondrial dysfunction. This technique allows for 24 acutely isolated sections from multiple brain regions of a single adult rat to be analyzed simultaneously with four sequential drug treatments, greatly advancing the ability to study mitochondrial physiology in adult neurological disorders.
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Affiliation(s)
- Nathan T Fried
- Thomas Jefferson University, Department of Neurology, Philadelphia, Pennsylvania
| | - Cynthia Moffat
- Thomas Jefferson University, Department of Pathology, Anatomy and Cell Biology, Philadelphia, Pennsylvania
| | - Erin L Seifert
- Thomas Jefferson University, Department of Pathology, Anatomy and Cell Biology, Philadelphia, Pennsylvania
| | - Michael L Oshinsky
- Thomas Jefferson University, Department of Neurology, Philadelphia, Pennsylvania;
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Veeraiah P, Noronha JM, Maitra S, Bagga P, Khandelwal N, Chakravarty S, Kumar A, Patel AB. Dysfunctional glutamatergic and γ-aminobutyric acidergic activities in prefrontal cortex of mice in social defeat model of depression. Biol Psychiatry 2014; 76:231-8. [PMID: 24239130 DOI: 10.1016/j.biopsych.2013.09.024] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 09/24/2013] [Accepted: 09/24/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Depression is a complex neuropsychiatric syndrome that is often very severe and life threatening. In spite of the remarkable progress in understanding the neural biology, the etiopathophysiology of depression is still elusive. In this study, we have investigated molecular mechanisms in the prefrontal cortex of mice showing depression-like phenotype induced by chronic defeat stress. METHODS Depression-like phenotype was induced in C57BL/6 mice by subjecting them to a 10-day social defeat paradigm. The metabolic activity of excitatory (glutamatergic) and inhibitory (γ-aminobutyric acid [GABA]ergic) neurons of the prefrontal cortex was measured by (1)H-[(13)C]-nuclear magnetic resonance spectroscopy together with infusion of [1,6-(13)C2]glucose. In addition, the expression level of genes associated with glutamatergic and GABAergic pathways was monitored by quantitative polymerase chain reaction. RESULTS Mice showing depression-like phenotype exhibit significant reduction in the levels of glutamate, glutamine, N-acetyl aspartate, and taurine in the prefrontal cortex. Most importantly, findings of reduced (13)C labeling of glutamate-C4, glutamate-C3, and GABA-C2 from [1,6-(13)C2]glucose indicate decreased glutamatergic and GABAergic neuronal metabolism and neurotransmitter cycling in the depressed mice. The reduced glutamine-C4 labeling suggests decreased neurotransmitter cycling in depression. Quantitative polymerase chain reaction analysis revealed reduced transcripts of Gad1 and Eaat2 genes, which code for enzymes involved in the synthesis of GABA and the clearance of glutamate from synapses, respectively. CONCLUSIONS These data indicate that the activities of glutamatergic and GABAergic neurons are reduced in mice showing a depression-like phenotype, which is supported by molecular data for the expression of genes involved in glutamate and GABA pathways.
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Affiliation(s)
- Pandichelvam Veeraiah
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Judith Miriam Noronha
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Swati Maitra
- Chemical Biology Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Puneet Bagga
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Nitin Khandelwal
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Sumana Chakravarty
- Chemical Biology Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Arvind Kumar
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India
| | - Anant B Patel
- Council of Scientific and Industrial Research-Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research-Indian Institute of Chemical Technology, Hyderabad, India.
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Compartmental Analysis of Metabolism by 13C Magnetic Resonance Spectroscopy. BRAIN ENERGY METABOLISM 2014. [DOI: 10.1007/978-1-4939-1059-5_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Befroy DE, Perry RJ, Jain N, Dufour S, Cline GW, Trimmer JK, Brosnan J, Rothman DL, Petersen KF, Shulman GI. Direct assessment of hepatic mitochondrial oxidative and anaplerotic fluxes in humans using dynamic 13C magnetic resonance spectroscopy. Nat Med 2014; 20:98-102. [PMID: 24317120 PMCID: PMC3947269 DOI: 10.1038/nm.3415] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/29/2013] [Indexed: 12/11/2022]
Abstract
Despite the central role of the liver in the regulation of glucose and lipid metabolism, there are currently no methods to directly assess hepatic oxidative metabolism in humans in vivo. By using a new (13)C-labeling strategy in combination with (13)C magnetic resonance spectroscopy, we show that rates of mitochondrial oxidation and anaplerosis in human liver can be directly determined noninvasively. Using this approach, we found the mean rates of hepatic tricarboxylic acid (TCA) cycle flux (VTCA) and anaplerotic flux (VANA) to be 0.43 ± 0.04 μmol g(-1) min(-1) and 0.60 ± 0.11 μmol g(-1) min(-1), respectively, in twelve healthy, lean individuals. We also found the VANA/VTCA ratio to be 1.39 ± 0.22, which is severalfold lower than recently published estimates using an indirect approach. This method will be useful for understanding the pathogenesis of nonalcoholic fatty liver disease and type 2 diabetes, as well as for assessing the effectiveness of new therapies targeting these pathways in humans.
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Affiliation(s)
- Douglas E Befroy
- 1] Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [3]
| | - Rachel J Perry
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA. [3]
| | - Nimit Jain
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sylvie Dufour
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gary W Cline
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | - Douglas L Rothman
- 1] Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Biomedical Engineering, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kitt Falk Petersen
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen, Denmark
| | - Gerald I Shulman
- 1] Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. [2] Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA. [3] Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA. [4] Novo Nordisk Foundation Center for Basic Metabolic Research, Copenhagen, Denmark
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Tiwari V, Veeraiah P, Subramaniam V, Patel AB. Differential effects of ethanol on regional glutamatergic and GABAergic neurotransmitter pathways in mouse brain. J Neurochem 2013; 128:628-40. [PMID: 24164397 DOI: 10.1111/jnc.12508] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 01/19/2023]
Abstract
This study investigates the effects of ethanol on neuronal and astroglial metabolism using (1)H-[(13)C]-NMR spectroscopy in conjunction with infusion of [1,6-(13)C2]/[1-(13)C]glucose or [2-(13)C]acetate, respectively. A three-compartment metabolic model was fitted to the (13)C turnover of GluC3 , GluC4, GABAC 2, GABAC 3, AspC3 , and GlnC4 from [1,6-(13)C2 ]glucose to determine the rates of tricarboxylic acid (TCA) and neurotransmitter cycle associated with glutamatergic and GABAergic neurons. The ratio of neurotransmitter cycle to TCA cycle fluxes for glutamatergic and GABAegic neurons was obtained from the steady-state [2-(13)C]acetate experiment and used as constraints during the metabolic model fitting. (1)H MRS measurement suggests that depletion of ethanol from cerebral cortex follows zero order kinetics with rate 0.18 ± 0.04 μmol/g/min. Acute exposure of ethanol reduces the level of glutamate and aspartate in cortical region. GlnC4 labeling was found to be unchanged from a 15 min infusion of [2-(13)C]acetate suggesting that acute ethanol exposure does not affect astroglial metabolism in naive mice. Rates of TCA and neurotransmitter cycle associated with glutamatergic and GABAergic neurons were found to be significantly reduced in cortical and subcortical regions. Acute exposure of ethanol perturbs the level of neurometabolites and decreases the excitatory and inhibitory activity differentially across the regions of brain. Depletion of ethanol and its effect on brain functions were measured using (1)H and (1)H-[(13)C]-NMR spectroscopy in conjunction with infusion of (13)C-labeled substrates. Ethanol depletion from brain follows zero order kinetics. Ethanol perturbs level of glutamate, and the excitatory and inhibitory activity in mice brain.
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Affiliation(s)
- Vivek Tiwari
- NMR Microimaging and Spectroscopy, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, India
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Lanz B, Xin L, Millet P, Gruetter R. In vivo quantification of neuro-glial metabolism and glial glutamate concentration using 1H-[13C] MRS at 14.1T. J Neurochem 2013; 128:125-39. [PMID: 24117599 DOI: 10.1111/jnc.12479] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 08/31/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022]
Abstract
Astrocytes have recently become a major center of interest in neurochemistry with the discoveries on their major role in brain energy metabolism. An interesting way to probe this glial contribution is given by in vivo (13) C NMR spectroscopy coupled with the infusion labeled glial-specific substrate, such as acetate. In this study, we infused alpha-chloralose anesthetized rats with [2-(13) C]acetate and followed the dynamics of the fractional enrichment (FE) in the positions C4 and C3 of glutamate and glutamine with high sensitivity, using (1) H-[(13) C] magnetic resonance spectroscopy (MRS) at 14.1T. Applying a two-compartment mathematical model to the measured time courses yielded a glial tricarboxylic acid (TCA) cycle rate (Vg ) of 0.27 ± 0.02 μmol/g/min and a glutamatergic neurotransmission rate (VNT ) of 0.15 ± 0.01 μmol/g/min. Glial oxidative ATP metabolism thus accounts for 38% of total oxidative metabolism measured by NMR. Pyruvate carboxylase (VPC ) was 0.09 ± 0.01 μmol/g/min, corresponding to 37% of the glial glutamine synthesis rate. The glial and neuronal transmitochondrial fluxes (Vx (g) and Vx (n) ) were of the same order of magnitude as the respective TCA cycle fluxes. In addition, we estimated a glial glutamate pool size of 0.6 ± 0.1 μmol/g. The effect of spectral data quality on the fluxes estimates was analyzed by Monte Carlo simulations. In this (13) C-acetate labeling study, we propose a refined two-compartment analysis of brain energy metabolism based on (13) C turnover curves of acetate, glutamate and glutamine measured with state of the art in vivo dynamic MRS at high magnetic field in rats, enabling a deeper understanding of the specific role of glial cells in brain oxidative metabolism. In addition, the robustness of the metabolic fluxes determination relative to MRS data quality was carefully studied.
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Affiliation(s)
- Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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