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Liu K, Zhou Y, Song X, Zeng J, Wang Z, Wang Z, Zhang H, Xu J, Li W, Gong Z, Wang M, Liu B, Xiao N, Liu K. Baicalin attenuates neuronal damage associated with SDH activation and PDK2-PDH axis dysfunction in early reperfusion. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 129:155570. [PMID: 38579645 DOI: 10.1016/j.phymed.2024.155570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 03/13/2024] [Accepted: 03/25/2024] [Indexed: 04/07/2024]
Abstract
BACKGROUND Energy deficiency and oxidative stress are interconnected during ischemia/reperfusion (I/R) and serve as potential targets for the treatment of cerebral ischemic stroke. Baicalin is a neuroprotective antioxidant, but the underlying mechanisms are not fully revealed. PURPOSE This study explored whether and how baicalin rescued neurons against ischemia/reperfusion (I/R) attack by focusing on the regulation of neuronal pyruvate dehydrogenase kinase 2 (PDK2)-pyruvate dehydrogenase (PDH) axis implicated with succinate dehydrogenase (SDH)-mediated oxidative stress. STUDY DESIGN The effect of the tested drug was explored in vitro and in vivo with the model of oxygen-glucose deprivation/reoxygenation (OGD/R) and middle cerebral artery occlusion/reperfusion (MCAO/R), respectively. METHODS Neuronal damage was evaluated according to cell viability, infarct area, and Nissl staining. Protein levels were measured by western blotting and immunofluorescence. Gene expression was investigated by RT-qPCR. Mitochondrial status was also estimated by fluorescence probe labeling. RESULTS SDH activation-induced excessive production of reactive oxygen species (ROS) changed the protein expression of Lon protease 1 (LonP1) and hypoxia-inducible factor-1ɑ (HIF-1ɑ) in the early stage of I/R, leading to an upregulation of PDK2 and a decrease in PDH activity in neurons and cerebral cortices. Treatment with baicalin prevented these alterations and ameliorated neuronal ATP production and survival. CONCLUSION Baicalin improves the function of the neuronal PDK2-PDH axis via suppression of SDH-mediated oxidative stress, revealing a new signaling pathway as a promising target under I/R conditions and the potential role of baicalin in the treatment of acute ischemic stroke.
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Affiliation(s)
- Kaili Liu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Ying Zhou
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Xianrui Song
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, PR China
| | - Jiahan Zeng
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Zhuqi Wang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Ziqing Wang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Honglei Zhang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Jiaxing Xu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Wenting Li
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Zixuan Gong
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Min Wang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Baolin Liu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China
| | - Na Xiao
- College of Agronomy, Shandong Agriculture University, Tai'an, Shandong 271018, PR China.
| | - Kang Liu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, 639 Longmian Road, Nanjing 211198, PR China.
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Mandal PK, Guha Roy R, Samkaria A, Maroon JC, Arora Y. In Vivo 13C Magnetic Resonance Spectroscopy for Assessing Brain Biochemistry in Health and Disease. Neurochem Res 2022; 47:1183-1201. [PMID: 35089504 DOI: 10.1007/s11064-022-03538-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/15/2022] [Accepted: 01/19/2022] [Indexed: 12/27/2022]
Abstract
Magnetic resonance spectroscopy (MRS) is a non-invasive technique that contributes to the elucidation of brain biochemistry. 13C MRS enables the detection of specific neurochemicals and their neuroenergetic correlation with neuronal function. The synergistic outcome of 13C MRS and the infusion of 13C-labeled substrates provide an understanding of neurometabolism and the role of glutamate/gamma-aminobutyric acid (GABA) neurotransmission in diseases, such as Alzheimer's disease, schizophrenia, and bipolar disorder. Moreover, 13C MRS provides a window into the altered flux rate of different pathways, including the tricarboxylic acid cycle (TCA) and the glutamate/glutamine/GABA cycle, in health and in various diseases. Notably, the metabolic flux rate of the TCA cycle often decreases in neurodegenerative diseases. Additionally, 13C MRS can be used to investigate several psychiatric and neurological disorders as it directly reflects the real-time production and alterations of key brain metabolites. This review aims to highlight the chronology, the technological advancements, and the applications of 13C MRS in various brain diseases.
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Affiliation(s)
- Pravat K Mandal
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India.
- Florey Institute of Neuroscience and Mental Health, Melbourne School of Medicine Campus, Melbourne, Australia.
| | - Rimil Guha Roy
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
| | - Avantika Samkaria
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
| | - Joseph C Maroon
- Department of Neurosurgery, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Yashika Arora
- Neuroimaging and Neurospectroscopy (NINS) Laboratory, National Brain Research Centre (NBRC), Gurgaon, India
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3
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Tefera TW, Steyn FJ, Ngo ST, Borges K. CNS glucose metabolism in Amyotrophic Lateral Sclerosis: a therapeutic target? Cell Biosci 2021; 11:14. [PMID: 33431046 PMCID: PMC7798275 DOI: 10.1186/s13578-020-00511-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/04/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disorder primarily characterized by selective degeneration of both the upper motor neurons in the brain and lower motor neurons in the brain stem and the spinal cord. The exact mechanism for the selective death of neurons is unknown. A growing body of evidence demonstrates abnormalities in energy metabolism at the cellular and whole-body level in animal models and in people living with ALS. Many patients with ALS exhibit metabolic changes such as hypermetabolism and body weight loss. Despite these whole-body metabolic changes being observed in patients with ALS, the origin of metabolic dysregulation remains to be fully elucidated. A number of pre-clinical studies indicate that underlying bioenergetic impairments at the cellular level may contribute to metabolic dysfunctions in ALS. In particular, defects in CNS glucose transport and metabolism appear to lead to reduced mitochondrial energy generation and increased oxidative stress, which seem to contribute to disease progression in ALS. Here, we review the current knowledge and understanding regarding dysfunctions in CNS glucose metabolism in ALS focusing on metabolic impairments in glucose transport, glycolysis, pentose phosphate pathway, TCA cycle and oxidative phosphorylation. We also summarize disturbances found in glycogen metabolism and neuroglial metabolic interactions. Finally, we discuss options for future investigations into how metabolic impairments can be modified to slow disease progression in ALS. These investigations are imperative for understanding the underlying causes of metabolic dysfunction and subsequent neurodegeneration, and to also reveal new therapeutic strategies in ALS.
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Affiliation(s)
- Tesfaye Wolde Tefera
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Frederik J Steyn
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia.,Center for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Shyuan T Ngo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia.,Center for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Karin Borges
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
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4
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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: 49] [Impact Index Per Article: 16.3] [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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5
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van Heijster FH, Heskamp S, Breukels V, Veltien A, Franssen GM, Jansen K(C, Boerman OC, Schalken JA, Scheenen TW, Heerschap A. Pyruvate-lactate exchange and glucose uptake in human prostate cancer cell models. A study in xenografts and suspensions by hyperpolarized [1- 13 C]pyruvate MRS and [ 18 F]FDG-PET. NMR IN BIOMEDICINE 2020; 33:e4362. [PMID: 32662543 PMCID: PMC7507209 DOI: 10.1002/nbm.4362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 05/04/2023]
Abstract
Reprogramming of energy metabolism in the development of prostate cancer can be exploited for a better diagnosis and treatment of the disease. The goal of this study was to determine whether differences in glucose and pyruvate metabolism of human prostate cancer cells with dissimilar aggressivenesses can be detected using hyperpolarized [1-13 C]pyruvate MRS and [18 F]FDG-PET imaging, and to evaluate whether these measures correlate. For this purpose, we compared murine xenografts of human prostate cancer LNCaP cells with those of more aggressive PC3 cells. [1-13 C]pyruvate was hyperpolarized by dissolution dynamic nuclear polarization (dDNP) and [1-13 C]pyruvate to lactate conversion was followed by 13 C MRS. Subsequently [18 F]FDG uptake was investigated by static and dynamic PET measurements. Standard uptake values (SUVs) for [18 F]FDG were significantly higher for xenografts of PC3 compared with those of LNCaP. However, we did not observe a difference in the average apparent rate constant kpl of 13 C label exchange from pyruvate to lactate between the tumor variants. A significant negative correlation was found between SUVs from [18 F]FDG PET measurements and kpl values for the xenografts of both tumor types. The kpl rate constant may be influenced by various factors, and studies with a range of prostate cancer cells in suspension suggest that LDH inhibition by pyruvate may be one of these. Our results indicate that glucose and pyruvate metabolism in the prostate cancer cell models differs from that in other tumor models and that [18 F]FDG-PET can serve as a valuable complementary tool in dDNP studies of aggressive prostate cancer with [1-13 C]pyruvate.
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Affiliation(s)
- Frits H.A. van Heijster
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Sandra Heskamp
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Vincent Breukels
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Andor Veltien
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Gerben M. Franssen
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | | | - Otto C. Boerman
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Jack A. Schalken
- Department of UrologyRadboud University Medical CenterNijmegenThe Netherlands
| | - Tom W.J. Scheenen
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
| | - Arend Heerschap
- Department of Radiology and Nuclear MedicineRadboud University Medical CenterNijmegenThe Netherlands
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Tefera TW, Borges K. Neuronal glucose metabolism is impaired while astrocytic TCA cycling is unaffected at symptomatic stages in the hSOD1 G93A mouse model of amyotrophic lateral sclerosis. J Cereb Blood Flow Metab 2019; 39:1710-1724. [PMID: 29553298 PMCID: PMC6727138 DOI: 10.1177/0271678x18764775] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although alterations in energy metabolism are known in ALS, the specific mechanisms leading to energy deficit are not understood. We measured metabolite levels derived from injected [1-13C]glucose and [1,2-13C]acetate (i.p.) in cerebral cortex and spinal cord extracts of wild type and hSOD1G93A mice at onset and mid disease stages using high-pressure liquid chromatography, 1H and 13C nuclear magnetic resonance spectroscopy. Levels of spinal and cortical CNS total lactate, [3-13C]lactate, total alanine and [3-13C]alanine, but not cortical glucose and [1-13C]glucose, were reduced mostly at mid stage indicating impaired glycolysis. The [1-13C]glucose-derived [4-13C]glutamate, [4-13C]glutamine and [2-13C]GABA amounts were diminished at mid stage in cortex and both time points in spinal cord, suggesting decreased [3-13C]pyruvate entry into the TCA cycle. Lack of changes in [1,2-13C]acetate-derived [4,5-13C]glutamate, [4,5-13C]glutamine and [1,2-13C]GABA levels indicate unchanged astrocytic 13C-acetate metabolism. Reduced levels of leucine, isoleucine and valine in CNS suggest compensatory breakdown to refill TCA cycle intermediate levels. Unlabelled, [2-13C] and [4-13C]GABA concentrations were decreased in spinal cord indicating that impaired glucose metabolism contributes to hyperexcitability and supporting the use of treatments which increase GABA amounts. In conclusion, CNS glucose metabolism is compromised, while astrocytic TCA cycling appears to be normal in the hSOD1G93A mouse model at symptomatic disease stages.
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Affiliation(s)
- Tesfaye W Tefera
- Department of Pharmacology, School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Karin Borges
- Department of Pharmacology, School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
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7
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Zhu XH, Chen W. In vivo X-Nuclear MRS Imaging Methods for Quantitative Assessment of Neuroenergetic Biomarkers in Studying Brain Function and Aging. Front Aging Neurosci 2018; 10:394. [PMID: 30538629 PMCID: PMC6277487 DOI: 10.3389/fnagi.2018.00394] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/13/2018] [Indexed: 12/19/2022] Open
Abstract
Brain relies on glucose and oxygen metabolisms to generate biochemical energy in the form of adenosine triphosphate (ATP) for supporting electrophysiological activities and neural signaling under resting or working state. Aging is associated with declined mitochondrial functionality and decreased cerebral energy metabolism, and thus, is a major risk factor in developing neurodegenerative diseases including Alzheimer’s disease (AD). However, there is an unmet need in the development of novel neuroimaging tools and sensitive biomarkers for detecting abnormal energy metabolism and impaired mitochondrial function, especially in an early stage of the neurodegenerative diseases. Recent advancements in developing multimodal high-field in vivo X-nuclear (e.g., 2H, 17O and 31P) MRS imaging techniques have shown promise for quantitative and noninvasive measurement of fundamental cerebral metabolic rates of glucose and oxygen consumption, ATP production as well as nicotinamide adenine dinucleotide (NAD) redox state in preclinical animal and human brains. These metabolic neuroimaging measurements could provide new insights and quantitative bioenergetic markers associated with aging processing and neurodegeneration and can therefore be employed to monitor disease progression and/or determine effectiveness of therapeutic intervention.
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Affiliation(s)
- Xiao-Hong Zhu
- Center for Magnetic Resonance Research (CMRR), Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Wei Chen
- Center for Magnetic Resonance Research (CMRR), Department of Radiology, School of Medicine, University of Minnesota, Minneapolis, MN, United States
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8
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Oehmigen M, Lindemann ME, Gratz M, Neji R, Hammers A, Sauer M, Lanz T, Quick HH. A dual-tuned 13 C/ 1 H head coil for PET/MR hybrid neuroimaging: Development, attenuation correction, and first evaluation. Med Phys 2018; 45:4877-4887. [PMID: 30182463 DOI: 10.1002/mp.13171] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/11/2018] [Accepted: 08/20/2018] [Indexed: 02/03/2023] Open
Abstract
PURPOSE This study aims to develop, implement, and evaluate a dual-tuned 13 C/1 H head coil for integrated positron emission tomography/magnetic resonance (PET/MR) neuroimaging. The radiofrequency (RF) head coil is designed for optimized MR imaging performance and PET transparency and attenuation correction (AC) is applied for accurate PET quantification. MATERIAL AND METHODS A dual-tuned 13 C/1 H RF head coil featuring a 16-rung birdcage was designed to be used for integrated PET/MR hybrid imaging. While the open birdcage design can be considered inherently PET transparent, all further electronic RF components were placed as far as possible outside of the field-of-view (FOV) of the PET detectors. The RF coil features a rigid geometry and thin-walled casing. Attenuation correction of the RF head coil is performed by generating and applying a dedicated 3D CT-based template attenuation map (μmap). Attenuation correction was systematically evaluated in phantom experiments using a large-volume cylindrical emission phantom filled with 18-F-Fluordesoxyglucose (FDG) radiotracer. The PET/MR imaging performance and PET attenuation correction were then evaluated in a patient study including six patients. RESULTS The dual-tuned RF head coil causes a mean relative attenuation difference of 8.8% across the volume of the cylindrical phantom, while the local relative differences range between 1% and 25%. Applying attenuation correction, the relative difference between the two measurements with and without RF coil is reduced to mean value of 0.5%, with local differences of ±3.6%. The quantitative results of the phantom measurements were corroborated by patient PET/MR measurements. Patient scans using the RF head coil show a decrease of PET signal of 5.17% ± 0.81% when compared to the setup without RF head coil in place, which served as a reference scan. When applying attenuation correction of the RF coil in the patient measurements, the mean difference to a measurement without RF coil was reduced to -0.87% ± 0.65%. CONCLUSION A dual-tuned 13 C/1 H RF head coil was designed and evaluated regarding its potential use in integrated PET/MR hybrid imaging. Attenuation correction was successfully applied. In conclusion, the RF head coil was successfully integrated into PET/MR hybrid imaging and can now be used for 13 C/1 H multinuclear hybrid neuroimaging in future studies.
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Affiliation(s)
- Mark Oehmigen
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Maike E Lindemann
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany
| | - Marcel Gratz
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany.,Erwin L. Hahn Institute for MR Imaging, University Duisburg-Essen, Essen, Germany
| | - Radhouene Neji
- MR Research Collaborations, Siemens Healthcare, Frimley, UK.,Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | - Alexander Hammers
- Division of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | | | | | - Harald H Quick
- High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany.,Erwin L. Hahn Institute for MR Imaging, University Duisburg-Essen, Essen, Germany
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9
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Analysis of naturally occurring mutations in the human uptake transporter NaCT important for bone and brain development and energy metabolism. Sci Rep 2018; 8:11330. [PMID: 30054523 PMCID: PMC6063891 DOI: 10.1038/s41598-018-29547-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/13/2018] [Indexed: 11/30/2022] Open
Abstract
The human uptake transporter NaCT is important for human brain development, brain function and energy metabolism and mediates the uptake of citrate and other intermediates of the tricarboxylic acid cycle from blood into neurons and hepatocytes. Mutations in the SLC13A5 gene encoding NaCT are associated with epileptic encephalopathy. To gain more insights into the transport mechanisms we analyzed the functional consequences of mutations in the SLC13A5 gene on NaCT-mediated transport function. Using HEK293 cells expressing wild-type and eight mutated NaCT proteins, we investigated the mRNA and protein amount as well as the protein localization of all NaCT variants. Furthermore, the impact on NaCT-mediated citrate uptake was measured. In addition, a structural model of the transport pore was generated to rationalize the consequences of the mutations on a structural basis. We demonstrated that all proteins were synthesized with an identical molecular weight as the wild-type transporter but several mutations (NaCTp.G219R, −p.G219E, −p.T227M, −p.L420P and −p.L488P) lead to a complete loss of NaCT-mediated citrate transport. This loss of transport activity can be explained on the basis of the developed structural model. This model may help in the further elucidation of the transport mechanism of this important uptake transporter.
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10
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Harris T, Azar A, Sapir G, Gamliel A, Nardi-Schreiber A, Sosna J, Gomori JM, Katz-Brull R. Real-time ex-vivo measurement of brain metabolism using hyperpolarized [1- 13C]pyruvate. Sci Rep 2018; 8:9564. [PMID: 29934508 PMCID: PMC6014998 DOI: 10.1038/s41598-018-27747-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 06/11/2018] [Indexed: 12/19/2022] Open
Abstract
The ability to directly monitor in vivo brain metabolism in real time in a matter of seconds using the dissolution dynamic nuclear polarization technology holds promise to aid the understanding of brain physiology in health and disease. However, translating the hyperpolarized signal observed in the brain to cerebral metabolic rates is not straightforward, as the observed in vivo signals reflect also the influx of metabolites produced in the body, the cerebral blood volume, and the rate of transport across the blood brain barrier. We introduce a method to study rapid metabolism of hyperpolarized substrates in the viable rat brain slices preparation, an established ex vivo model of the brain. By retrospective evaluation of tissue motion and settling from analysis of the signal of the hyperpolarized [1-13C]pyruvate precursor, the T1s of the metabolites and their rates of production can be determined. The enzymatic rates determined here are in the range of those determined previously with classical biochemical assays and are in agreement with hyperpolarized metabolite relative signal intensities observed in the rodent brain in vivo.
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Affiliation(s)
- Talia Harris
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Assad Azar
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Gal Sapir
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Ayelet Gamliel
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Atara Nardi-Schreiber
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - J Moshe Gomori
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel
| | - Rachel Katz-Brull
- Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, 9112001, Israel.
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11
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Barros LF, Bolaños JP, Bonvento G, Bouzier-Sore AK, Brown A, Hirrlinger J, Kasparov S, Kirchhoff F, Murphy AN, Pellerin L, Robinson MB, Weber B. Current technical approaches to brain energy metabolism. Glia 2018; 66:1138-1159. [PMID: 29110344 PMCID: PMC5903992 DOI: 10.1002/glia.23248] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/14/2017] [Accepted: 10/04/2017] [Indexed: 12/19/2022]
Abstract
Neuroscience is a technology-driven discipline and brain energy metabolism is no exception. Once satisfied with mapping metabolic pathways at organ level, we are now looking to learn what it is exactly that metabolic enzymes and transporters do and when, where do they reside, how are they regulated, and how do they relate to the specific functions of neurons, glial cells, and their subcellular domains and organelles, in different areas of the brain. Moreover, we aim to quantify the fluxes of metabolites within and between cells. Energy metabolism is not just a necessity for proper cell function and viability but plays specific roles in higher brain functions such as memory processing and behavior, whose mechanisms need to be understood at all hierarchical levels, from isolated proteins to whole subjects, in both health and disease. To this aim, the field takes advantage of diverse disciplines including anatomy, histology, physiology, biochemistry, bioenergetics, cellular biology, molecular biology, developmental biology, neurology, and mathematical modeling. This article presents a well-referenced synopsis of the technical side of brain energy metabolism research. Detail and jargon are avoided whenever possible and emphasis is given to comparative strengths, limitations, and weaknesses, information that is often not available in regular articles.
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Affiliation(s)
- L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, 5110466, Chile
| | - Juan P Bolaños
- Instituto de Biologia Funcional y Genomica-CSIC, Universidad de Salamanca, CIBERFES, Salamanca, 37007, Spain
| | - Gilles Bonvento
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Anne-Karine Bouzier-Sore
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS-Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Angus Brown
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Johannes Hirrlinger
- Carl Ludwig Institute of Physiology, University of Leipzig, Liebigstr. 27, D-04103, Leipzig, Germany
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, D-37075, Germany
| | - Sergey Kasparov
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, BS8 1TD, United Kingdom
- Baltic Federal University, Kalinigrad, Russian Federation
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Building 48, Homburg, 66421, Germany
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093
| | - Luc Pellerin
- Département de Physiologie, 7 rue du Bugnon, Lausanne, CH1005, Switzerland
| | - Michael B Robinson
- Department of Pediatrics, and Department of Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Zurich, Switzerland
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12
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El Hamrani D, Gin H, Gallis JL, Bouzier-Sore AK, Beauvieux MC. Consumption of Alcopops During Brain Maturation Period: Higher Impact of Fructose Than Ethanol on Brain Metabolism. Front Nutr 2018; 5:33. [PMID: 29868598 PMCID: PMC5952002 DOI: 10.3389/fnut.2018.00033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/18/2018] [Indexed: 12/26/2022] Open
Abstract
Alcopops are flavored alcoholic beverages sweetened by sodas, known to contain fructose. These drinks have the goal of democratizing alcohol among young consumers (12-17 years old) and in the past few years have been considered as fashionable amongst teenagers. Adolescence, however, is a key period for brain maturation, occurring in the prefrontal cortex and limbic system until 21 years old. Therefore, this drinking behavior has become a public health concern. Despite the extensive literature concerning the respective impacts of either fructose or ethanol on brain, the effects following joint consumption of these substrates remains unknown. Our objective was to study the early brain modifications induced by a combined diet of high fructose (20%) and moderate amount of alcohol in young rats by 13C Nuclear Magnetic Resonance (NMR) spectroscopy. Wistar rats had isocaloric pair-fed diets containing fructose (HF, 20%), ethanol (Et, 0.5 g/day/kg) or both substrates at the same time (HFEt). After 6 weeks of diet, the rats were infused with 13C-glucose and brain perchloric acid extracts were analyzed by NMR spectroscopy (1H and 13C). Surprisingly, the most important modifications of brain metabolism were observed under fructose diet. Alterations, observed after only 6 weeks of diet, show that the brain is vulnerable at the metabolic level to fructose consumption during late-adolescence throughout adulthood in rats. The main result was an increase in oxidative metabolism compared to glycolysis, which may impact lactate levels in the brain and may, at least partially, explain memory impairment in teenagers consuming alcopops.
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Affiliation(s)
- Dounia El Hamrani
- UMR5536 Centre de Resonance Magnetique des Systemes Biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, LabEx TRAIL, Bordeaux, France
| | - Henri Gin
- UMR5536 Centre de Resonance Magnetique des Systemes Biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, LabEx TRAIL, Bordeaux, France.,Service de Nutrition et Diabétologie, Hôpital Haut-Lévêque, Pessac, France
| | - Jean-Louis Gallis
- UMR5536 Centre de Resonance Magnetique des Systemes Biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, LabEx TRAIL, Bordeaux, France
| | - Anne-Karine Bouzier-Sore
- UMR5536 Centre de Resonance Magnetique des Systemes Biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, LabEx TRAIL, Bordeaux, France
| | - Marie-Christine Beauvieux
- UMR5536 Centre de Resonance Magnetique des Systemes Biologiques (CRMSB), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux, LabEx TRAIL, Bordeaux, France
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Abstract
Lactate in the brain has long been associated with ischaemia; however, more recent evidence shows that it can be found there under physiological conditions. In the brain, lactate is formed predominantly in astrocytes from glucose or glycogen in response to neuronal activity signals. Thus, neurons and astrocytes show tight metabolic coupling. Lactate is transferred from astrocytes to neurons to match the neuronal energetic needs, and to provide signals that modulate neuronal functions, including excitability, plasticity and memory consolidation. In addition, lactate affects several homeostatic functions. Overall, lactate ensures adequate energy supply, modulates neuronal excitability levels and regulates adaptive functions in order to set the 'homeostatic tone' of the nervous system.
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Flament J, Hantraye P, Valette J. In Vivo Multidimensional Brain Imaging in Huntington's Disease Animal Models. Methods Mol Biol 2018; 1780:285-301. [PMID: 29856025 DOI: 10.1007/978-1-4939-7825-0_15] [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: 06/08/2023]
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disorder caused by an abnormal expansion of a CAG repeat located in the gene encoding for huntingtin protein. This mutation induces the expression of a polyglutamine stretch in the mutated protein resulting in the modification of various biological properties of the wild-type protein and the progressive appearance of motor, cognitive, and psychiatric disorders that are typically associated to this condition. Although the exact neuropathological mechanisms of degeneration are still not fully understood, HD pathology is characterized by severe neuronal losses in various brain regions including the basal ganglia and many cortical areas. Early signs of astrogliosis may precede actual neuronal degeneration. Early metabolic impairment at least in part associated with mitochondrial complex II deficiency may play a key role in huntingtin-induced mechanisms of neurodegeneration. Clinical trials are actively prepared including various gene-silencing approaches aiming at decreasing mutated huntingtin production. However, with the lack of a specific imaging biomarker capable of visualizing mutated huntingtin or huntingtin aggregates, there is a need for surrogate markers of huntingtin neurodegeneration. MRI and caudate nucleus atrophy is one of the most sensitive imaging biomarkers of HD. As such it can be used as a means to study disease progression and potential halting of the neurodegenerative process by therapeutic intervention, but this marker relies on actual neuronal loss which is a somewhat a late event in the pathology. As a means to develop, characterize and evaluate new, potentially earlier biomarkers of HD pathology we have recently embarked on a series of NMR developments looking for brain imaging techniques that allow for noninvasive longitudinal evaluation/characterization of functional alterations in animal models of HD. This chapter describes an assemblage of innovative NMR methods that have proved useful in detecting pathological cell dysfunctions in various preclinical models of HD.
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Affiliation(s)
- Julien Flament
- CEA, DRF, Institut de biologie François Jacob, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France
- INSERM, US27, Fontenay-aux-Roses, France
| | - Philippe Hantraye
- CEA, DRF, Institut de biologie François Jacob, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France.
- INSERM, US27, Fontenay-aux-Roses, France.
- CNRS, CEA, Paris-Sud Univ., Univ. Paris-Saclay, Neurodegenerative Diseases Laboratory (UMR9199), Fontenay-aux-Roses, France.
| | - Julien Valette
- CEA, DRF, Institut de biologie François Jacob, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France
- CNRS, CEA, Paris-Sud Univ., Univ. Paris-Saclay, Neurodegenerative Diseases Laboratory (UMR9199), Fontenay-aux-Roses, France
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15
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Bonvento G, Valette J, Flament J, Mochel F, Brouillet E. Imaging and spectroscopic approaches to probe brain energy metabolism dysregulation in neurodegenerative diseases. J Cereb Blood Flow Metab 2017; 37:1927-1943. [PMID: 28276944 PMCID: PMC5464722 DOI: 10.1177/0271678x17697989] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/10/2017] [Accepted: 02/06/2017] [Indexed: 12/14/2022]
Abstract
Changes in energy metabolism are generally considered to play an important role in neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's diseases. Whether these changes are causal or simply a part of self-defense mechanisms is a matter of debate. Furthermore, energy defects have often been discussed solely in the context of their probable neuronal origin without considering the cellular heterogeneity of the brain. Recent data point towards the existence of a tri-cellular compartmentation of brain energy metabolism between neurons, astrocytes, and oligodendrocytes, each cell type having a distinctive metabolic profile. Still, the number of methods to follow energy metabolism in patients is extremely limited and existing clinical techniques are blind to most cellular processes. There is a need to better understand how brain energy metabolism is regulated in health and disease through experiments conducted at different scales in animal models to implement new methods in the clinical setting. The purpose of this review is to offer a brief overview of the broad spectrum of methodological approaches that have emerged in recent years to probe energy metabolism in more detail. We conclude that multi-modal neuroimaging is needed to follow non-cell autonomous energy metabolism dysregulation in neurodegenerative diseases.
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Affiliation(s)
- Gilles Bonvento
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Julien Valette
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Julien Flament
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
- INSERM US 27, Molecular Imaging Research Center (MIRCen), Fontenay-aux-Roses, France
| | - Fanny Mochel
- INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 6, Institut du Cerveau et de la Moelle épinière, Paris, France
- Department of Genetics, AP-HP Hôpital Pitié-Salpêtrière, Paris, France
- University Pierre and Marie Curie, Neurometabolic Research Group, Paris, France
| | - Emmanuel Brouillet
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
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16
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Mazuel L, Blanc J, Repond C, Bouchaud V, Raffard G, Déglon N, Bonvento G, Pellerin L, Bouzier-Sore AK. A neuronal MCT2 knockdown in the rat somatosensory cortex reduces both the NMR lactate signal and the BOLD response during whisker stimulation. PLoS One 2017; 12:e0174990. [PMID: 28388627 PMCID: PMC5384673 DOI: 10.1371/journal.pone.0174990] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/17/2017] [Indexed: 12/20/2022] Open
Abstract
Although several in vitro and ex vivo evidence support the existence of lactate exchange between astrocytes and neurons, a direct demonstration in vivo is still lacking. In the present study, a lentiviral vector carrying a short hairpin RNA (shRNA) was used to downregulate the expression of the monocarboxylate transporter type 2 (MCT2) in neurons of the rat somatosensory cortex (called S1BF) by ~ 25%. After one hour of whisker stimulation, HRMAS 1H-NMR spectroscopy analysis of S1BF perchloric acid extracts showed that while an increase in lactate content is observed in both uninjected and shRNA-control injected extracts, such an effect was abrogated in shMCT2 injected rats. A 13C-incorporation analysis following [1-13C]glucose infusion during the stimulation confirmed that the elevated lactate observed during activation originates from newly synthesized [3-13C]lactate, with blood-derived [1-13C]glucose being the precursor. Moreover, the analysis of the 13C-labeling of glutamate in position C3 and C4 indicates that upon activation, there is an increase in TCA cycle velocity for control rats while a decrease is observed for MCT2 knockdown animals. Using in vivo localized 1H-NMR spectroscopy, an increase in lactate levels is observed in the S1BF area upon whisker stimulation for shRNA-control injected rats but not for MCT2 knockdown animals. Finally, while a robust BOLD fMRI response was evidenced in control rats, it was absent in MCT2 knockdown rats. These data not only demonstrate that glucose-derived lactate is locally produced following neuronal activation but also suggest that its use by neurons via MCT2 is probably essential to maintain synaptic activity within the barrel cortex.
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Affiliation(s)
- Leslie Mazuel
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Jordy Blanc
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Cendrine Repond
- Département de Physiologie, 7 rue du Bugnon, CH Lausanne, Switzerland
| | - Véronique Bouchaud
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Gérard Raffard
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Nicole Déglon
- Department of Clinical Neurosciences, Laboratory of Cellular and Molecular Neurotherapies (LCMN), Lausanne University Hospital, Lausanne, Switzerland
- Neurosciences Research Center (CRN), LCMN, Lausanne University Hospital, Lausanne, Switzerland
| | - Gilles Bonvento
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Luc Pellerin
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
- Département de Physiologie, 7 rue du Bugnon, CH Lausanne, Switzerland
| | - Anne-Karine Bouzier-Sore
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
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Cerdán S. Twenty-seven Years of Cerebral Pyruvate Recycling. Neurochem Res 2017; 42:1621-1628. [PMID: 28101749 DOI: 10.1007/s11064-017-2173-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/02/2017] [Accepted: 01/02/2017] [Indexed: 10/20/2022]
Abstract
Cerebral pyruvate recycling is a metabolic pathway deriving carbon skeletons and reducing equivalents from mitochondrial oxaloacetate and malate, to the synthesis of mitochondrial and cytosolic pyruvate, lactate and alanine. The pathway allows both, to provide the tricarboxylic acid cycle with pyruvate molecules produced from alternative substrates to glucose and, to generate reducing equivalents necessary for the operation of NADPH requiring processes. At the cellular level, pyruvate recycling involves the activity of malic enzyme, or the combined activities of phosphoenolpyruvate carboxykinase and pyruvate kinase, as well as of those transporters of the inner mitochondrial membrane exchanging the corresponding intermediates. Its cellular localization between the neuronal or astrocytic compartments of the in vivo brain has been controversial, with evidences favoring either a primarily neuronal or glial localizations, more recently accepted to occur in both environments. This review provides a brief history on the detection and characterization of the pathway, its relations with the early developments of cerebral high resolution 13C NMR, and its potential neuroprotective functions under hypoglycemic conditions or ischemic redox stress.
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Affiliation(s)
- Sebastián Cerdán
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC/UAM, c/ Arturo Duperier 4, 28029, Madrid, Spain.
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18
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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: 1.8] [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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19
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Functional metabolic interactions of human neuron-astrocyte 3D in vitro networks. Sci Rep 2016; 6:33285. [PMID: 27619889 PMCID: PMC5020407 DOI: 10.1038/srep33285] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 08/19/2016] [Indexed: 01/27/2023] Open
Abstract
The generation of human neural tissue-like 3D structures holds great promise for disease modeling, drug discovery and regenerative medicine strategies. Promoting the establishment of complex cell-cell interactions, 3D culture systems enable the development of human cell-based models with increased physiological relevance, over monolayer cultures. Here, we demonstrate the establishment of neuronal and astrocytic metabolic signatures and shuttles in a human 3D neural cell model, namely the glutamine-glutamate-GABA shuttle. This was indicated by labeling of neuronal GABA following incubation with the glia-specific substrate [2-(13)C]acetate, which decreased by methionine sulfoximine-induced inhibition of the glial enzyme glutamine synthetase. Cell metabolic specialization was further demonstrated by higher pyruvate carboxylase-derived labeling in glutamine than in glutamate, indicating its activity in astrocytes and not in neurons. Exposure to the neurotoxin acrylamide resulted in intracellular accumulation of glutamate and decreased GABA synthesis. These results suggest an acrylamide-induced impairment of neuronal synaptic vesicle trafficking and imbalanced glutamine-glutamate-GABA cycle, due to loss of cell-cell contacts at synaptic sites. This work demonstrates, for the first time to our knowledge, that neural differentiation of human cells in a 3D setting recapitulates neuronal-astrocytic metabolic interactions, highlighting the relevance of these models for toxicology and better understanding the crosstalk between human neural cells.
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20
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Valette J, Tiret B, Boumezbeur F. Experimental strategies for in vivo 13C NMR spectroscopy. Anal Biochem 2016; 529:216-228. [PMID: 27515993 DOI: 10.1016/j.ab.2016.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/24/2016] [Accepted: 08/04/2016] [Indexed: 11/15/2022]
Abstract
In vivo carbon-13 (13C) MRS opens unique insights into the metabolism of intact organisms, and has led to major advancements in the understanding of cellular metabolism under normal and pathological conditions in various organs such as skeletal muscles, the heart, the liver and the brain. However, the technique comes at the expense of significant experimental difficulties. In this review we focus on the experimental aspects of non-hyperpolarized 13C MRS in vivo. Some of the enrichment strategies which have been proposed so far are described; the various MRS acquisition paradigms to measure 13C labeling are then presented. Finally, practical aspects of 13C spectral quantification are discussed.
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Affiliation(s)
- Julien Valette
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), MIRCen, F-92260 Fontenay-aux-Roses, France; Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France.
| | - Brice Tiret
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), MIRCen, F-92260 Fontenay-aux-Roses, France; Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, UMR 9199, Neurodegenerative Diseases Laboratory, F-92260 Fontenay-aux-Roses, France
| | - Fawzi Boumezbeur
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Institut d'Imagerie Biomédicale (I2BM), NeuroSpin, F-91190 Gif-sur-Yvette, France
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21
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Dehghani M M, Lanz B, Duarte JMN, Kunz N, Gruetter R. Refined Analysis of Brain Energy Metabolism Using In Vivo Dynamic Enrichment of 13C Multiplets. ASN Neuro 2016; 8:8/2/1759091416632342. [PMID: 26969691 PMCID: PMC4790427 DOI: 10.1177/1759091416632342] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/30/2015] [Indexed: 11/18/2022] Open
Abstract
Carbon-13 nuclear magnetic resonance spectroscopy in combination with the infusion of 13C-labeled precursors is a unique approach to study in vivo brain energy metabolism. Incorporating the maximum information available from in vivo localized 13C spectra is of importance to get broader knowledge on cerebral metabolic pathways. Metabolic rates can be quantitatively determined from the rate of 13C incorporation into amino acid neurotransmitters such as glutamate and glutamine using suitable mathematical models. The time course of multiplets arising from 13C-13C coupling between adjacent carbon atoms was expected to provide additional information for metabolic modeling leading to potential improvements in the estimation of metabolic parameters. The aim of the present study was to extend two-compartment neuronal/glial modeling to include dynamics of 13C isotopomers available from fine structure multiplets in 13C spectra of glutamate and glutamine measured in vivo in rats brain at 14.1 T, termed bonded cumomer approach. Incorporating the labeling time courses of 13C multiplets of glutamate and glutamine resulted in elevated precision of the estimated fluxes in rat brain as well as reduced correlations between them.
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Affiliation(s)
- Masoumeh Dehghani M
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - Bernard Lanz
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
| | - João M N Duarte
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland Department of Radiology, University of Lausanne, Switzerland
| | - Nicolas Kunz
- CIBM-AIT, Ecole Polytechnique Fédérale de Lausanne, Switzerland
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland Department of Radiology, University of Lausanne, Switzerland Department of Radiology, University of Geneva, Switzerland
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22
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Hardies K, de Kovel CGF, Weckhuysen S, Asselbergh B, Geuens T, Deconinck T, Azmi A, May P, Brilstra E, Becker F, Barisic N, Craiu D, Braun KP, Lal D, Thiele H, Schubert J, Weber Y, van ‘t Slot R, Nürnberg P, Balling R, Timmerman V, Lerche H, Maudsley S, Helbig I, Suls A, Koeleman BP. Recessive mutations inSLC13A5result in a loss of citrate transport and cause neonatal epilepsy, developmental delay and teeth hypoplasia. Brain 2015; 138:3238-50. [DOI: 10.1093/brain/awv263] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/07/2015] [Indexed: 12/21/2022] Open
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23
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Cerdan S, Lizarbe B. Editorial: "Transcellular Cycles Underlying Neurotransmission". Front Nutr 2015; 2:18. [PMID: 26176010 PMCID: PMC4484339 DOI: 10.3389/fnut.2015.00018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/11/2015] [Indexed: 12/02/2022] Open
Affiliation(s)
- Sebastián Cerdan
- Instituto Investigaciones Biomédicas "Alberto Sols" CSIC-UAM , Madrid , Spain
| | - Blanca Lizarbe
- Laboratory for Functional and Metabolic Imaging (LIFMET), SB IPSB, École Polytechnique Fédéral de Lausanne , Lausanne , Switzerland
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24
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Liu CH. Anatomical, functional and molecular biomarker applications of magnetic resonance neuroimaging. FUTURE NEUROLOGY 2015; 10:49-65. [DOI: 10.2217/fnl.14.60] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ABSTRACT MRI and magnetic resonance spectroscopy (MRS) along with computed tomography and PET are the most common imaging modalities used in the clinics to detect structural abnormalities and pathological conditions in the brain. MRI generates superb image resolution/contrast without radiation exposure that is associated with computed tomography and PET; MRS and spectroscopic imaging technologies allow us to measure changes in brain biochemistry. Increasingly, neurobiologists and MRI scientists are collaborating to solve neuroscience problems across sub-cellular through anatomical levels. To achieve successful cross-disciplinary collaborations, neurobiologists must have sufficient knowledge of magnetic resonance principles and applications in order to effectively communicate with their MRI colleagues. This review provides an overview of magnetic resonance techniques and how they can be used to gain insight into the active brain at the anatomical, functional and molecular levels with the goal of encouraging neurobiologists to include MRI/MRS as a research tool in their endeavors.
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25
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Abstract
Human adults produce around 1000 mmol of ammonia daily. Some is reutilized in biosynthesis. The remainder is waste and neurotoxic. Eventually most is excreted in urine as urea, together with ammonia used as a buffer. In extrahepatic tissues, ammonia is incorporated into nontoxic glutamine and released into blood. Large amounts are metabolized by the kidneys and small intestine. In the intestine, this yields ammonia, which is sequestered in portal blood and transported to the liver for ureagenesis, and citrulline, which is converted to arginine by the kidneys. The amazing developments in NMR imaging and spectroscopy and molecular biology have confirmed concepts derived from early studies in animals and cell cultures. The processes involved are exquisitely tuned. When they are faulty, ammonia accumulates. Severe acute hyperammonemia causes a rapidly progressive, often fatal, encephalopathy with brain edema. Chronic milder hyperammonemia causes a neuropsychiatric illness. Survivors of severe neonatal hyperammonemia have structural brain damage. Proposed explanations for brain edema are an increase in astrocyte osmolality, generally attributed to glutamine accumulation, and cytotoxic oxidative/nitrosative damage. However, ammonia neurotoxicity is multifactorial, with disturbances also in neurotransmitters, energy production, anaplerosis, cerebral blood flow, potassium, and sodium. Around 90% of hyperammonemic patients have liver disease. Inherited defects are rare. They are being recognized increasingly in adults. Deficiencies of urea cycle enzymes, citrin, and pyruvate carboxylase demonstrate the roles of isolated pathways in ammonia metabolism. Phenylbutyrate is used routinely to treat inherited urea cycle disorders, and its use for hepatic encephalopathy is under investigation.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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