1
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Wang MY, Zhou Y, Li WL, Zhu LQ, Liu D. Friend or foe: Lactate in neurodegenerative diseases. Ageing Res Rev 2024; 101:102452. [PMID: 39127445 DOI: 10.1016/j.arr.2024.102452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 08/07/2024] [Indexed: 08/12/2024]
Abstract
Lactate, a byproduct of glycolysis, was considered as a metabolic waste until identified by studies on the Warburg effect. Increasing evidence elucidates that lactate functions as energy fuel, signaling molecule, and donor for protein lactylation. Altered lactate utilization is a common metabolic feature of the onset and progression of neurodegenerative diseases, such as Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease and Huntington's disease. This review offers an overview of lactate metabolism from the perspective of production, transportation and clearance, and the role of lactate in neurodegenerative progression, as well as a summary of protein lactylation and the signaling function of lactate in neurodegenerative diseases. Besides, this review delves into the dual roles of changed lactate metabolism during neurodegeneration and explores prospective therapeutic methods targeting lactate. We propose that elucidating the correlation between lactate and neurodegeneration is pivotal for exploring innovative therapeutic interventions for neurodegenerative diseases.
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Affiliation(s)
- Ming-Yu Wang
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yang Zhou
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Wen-Lian Li
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Ling-Qiang Zhu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
| | - Dan Liu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
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2
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Späte E, Zhou B, Sun T, Kusch K, Asadollahi E, Siems SB, Depp C, Werner HB, Saher G, Hirrlinger J, Möbius W, Nave KA, Goebbels S. Downregulated expression of lactate dehydrogenase in adult oligodendrocytes and its implication for the transfer of glycolysis products to axons. Glia 2024; 72:1374-1391. [PMID: 38587131 DOI: 10.1002/glia.24533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/09/2024]
Abstract
Oligodendrocytes and astrocytes are metabolically coupled to neuronal compartments. Pyruvate and lactate can shuttle between glial cells and axons via monocarboxylate transporters. However, lactate can only be synthesized or used in metabolic reactions with the help of lactate dehydrogenase (LDH), a tetramer of LDHA and LDHB subunits in varying compositions. Here we show that mice with a cell type-specific disruption of both Ldha and Ldhb genes in oligodendrocytes lack a pathological phenotype that would be indicative of oligodendroglial dysfunctions or lack of axonal metabolic support. Indeed, when combining immunohistochemical, electron microscopical, and in situ hybridization analyses in adult mice, we found that the vast majority of mature oligodendrocytes lack detectable expression of LDH. Even in neurodegenerative disease models and in mice under metabolic stress LDH was not increased. In contrast, at early development and in the remyelinating brain, LDHA was readily detectable in immature oligodendrocytes. Interestingly, by immunoelectron microscopy LDHA was particularly enriched at gap junctions formed between adjacent astrocytes and at junctions between astrocytes and oligodendrocytes. Our data suggest that oligodendrocytes metabolize lactate during development and remyelination. In contrast, for metabolic support of axons mature oligodendrocytes may export their own glycolysis products as pyruvate rather than lactate. Lacking LDH, these oligodendrocytes can also "funnel" lactate through their "myelinic" channels between gap junction-coupled astrocytes and axons without metabolizing it. We suggest a working model, in which the unequal cellular distribution of LDH in white matter tracts facilitates a rapid and efficient transport of glycolysis products among glial and axonal compartments.
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Affiliation(s)
- Erik Späte
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Baoyu Zhou
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Laboratory of Molecular Neurobiology, Department of Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Ebrahim Asadollahi
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sophie B Siems
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Constanze Depp
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Johannes Hirrlinger
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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3
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Barbaresi P, Fabri M, Lorenzi T, Sagrati A, Morroni M. Intrinsic organization of the corpus callosum. Front Physiol 2024; 15:1393000. [PMID: 39035452 PMCID: PMC11259024 DOI: 10.3389/fphys.2024.1393000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/16/2024] [Indexed: 07/23/2024] Open
Abstract
The corpus callosum-the largest commissural fiber system connecting the two cerebral hemispheres-is considered essential for bilateral sensory integration and higher cognitive functions. Most studies exploring the corpus callosum have examined either the anatomical, physiological, and neurochemical organization of callosal projections or the functional and/or behavioral aspects of the callosal connections after complete/partial callosotomy or callosal lesion. There are no works that address the intrinsic organization of the corpus callosum. We review the existing information on the activities that take place in the commissure in three sections: I) the topographical and neurochemical organization of the intracallosal fibers, II) the role of glia in the corpus callosum, and III) the role of the intracallosal neurons.
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Affiliation(s)
- Paolo Barbaresi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Mara Fabri
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Teresa Lorenzi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Andrea Sagrati
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Manrico Morroni
- Electron Microscopy Unit, Azienda Ospedaliero-Universitaria, Ancona, Italy
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Oliveira A, Azevedo M, Seixas R, Martinho R, Serrão P, Moreira-Rodrigues M. Glucose may Contribute to Retrieval and Reconsolidation of Contextual Fear Memory Through Hippocampal Nr4a3 and Bdnf mRNA Expression and May Act Synergically with Adrenaline. Mol Neurobiol 2024; 61:2784-2797. [PMID: 37938511 PMCID: PMC11043124 DOI: 10.1007/s12035-023-03745-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/27/2023] [Indexed: 11/09/2023]
Abstract
Adrenaline (Ad) and glucose released into the bloodstream during stress may strengthen contextual fear memory. However, no previous studies have detached the effects of glucose from Ad in this paradigm. Using Ad-deficient mice, we aimed to evaluate the effect of glucose on contextual fear memory when endogenous Ad is absent. Fear conditioning was performed in wild-type (WT) and Ad-deficient mice (129 × 1/SvJ) administered with glucose (30 or 10 mg/kg; i.p.) or/and Ad (0.01 mg/kg; i.p.) or vehicle (0.9% NaCl; i.p.). Catecholamines were quantified using HPLC-ED. Real-time qPCR was used to assess mRNA expression of hippocampal genes. WT and Ad-deficient mice display increased contextual fear memory when administered with glucose both in acquisition and context days when compared to vehicle. Also, Nr4a3 and Bdnf mRNA expression increased in glucose-administered Ad-deficient mice. Sub-effective doses of glucose plus Ad administered simultaneously to Ad-deficient mice increased contextual fear memory, contrary to independent sub-effective doses. Concluding, glucose may be an important part of the peripheral to central pathway involved in the retrieval and reconsolidation of fear contextual memories independently of Ad, possibly due to increased hippocampal Nr4a3 and Bdnf gene expression. Furthermore, Ad and glucose may act synergically to strengthen contextual fear memory.
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Affiliation(s)
- Ana Oliveira
- Department of Immuno-physiology and Pharmacology, Laboratory of General Physiology, School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), R. Jorge Viterbo Ferreira, 228, Building 2, Floor 4, Cabinet 22, Porto, 4050-313, Portugal
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal
| | - Márcia Azevedo
- Department of Immuno-physiology and Pharmacology, Laboratory of General Physiology, School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), R. Jorge Viterbo Ferreira, 228, Building 2, Floor 4, Cabinet 22, Porto, 4050-313, Portugal
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal
| | - Rafaela Seixas
- Department of Immuno-physiology and Pharmacology, Laboratory of General Physiology, School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), R. Jorge Viterbo Ferreira, 228, Building 2, Floor 4, Cabinet 22, Porto, 4050-313, Portugal
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal
| | - Raquel Martinho
- Department of Immuno-physiology and Pharmacology, Laboratory of General Physiology, School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), R. Jorge Viterbo Ferreira, 228, Building 2, Floor 4, Cabinet 22, Porto, 4050-313, Portugal
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal
| | - Paula Serrão
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal
- Department of Biomedicine, Faculty of Medicine, University of Porto (FMUP), Porto, Portugal
| | - Mónica Moreira-Rodrigues
- Department of Immuno-physiology and Pharmacology, Laboratory of General Physiology, School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), R. Jorge Viterbo Ferreira, 228, Building 2, Floor 4, Cabinet 22, Porto, 4050-313, Portugal.
- Center for Drug Discovery and Innovative Medicines, University of Porto (MedInUP), Porto, Portugal.
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5
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Marcora MS, Mattera VS, Goñi P, Aybar F, Correale JD, Pasquini JM. Iron deficiency in astrocytes alters cellular status and impacts on oligodendrocyte differentiation. J Neurosci Res 2024; 102:e25334. [PMID: 38656648 DOI: 10.1002/jnr.25334] [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: 06/27/2023] [Revised: 04/01/2024] [Accepted: 04/04/2024] [Indexed: 04/26/2024]
Abstract
Iron deficiency (ID) has been shown to affect central nervous system (CNS) development and induce hypomyelination. Previous work from our laboratory in a gestational ID model showed that both oligodendrocyte (OLG) and astrocyte (AST) maturation was impaired. To explore the contribution of AST iron to the myelination process, we generated an in vitro ID model by silencing divalent metal transporter 1 (DMT1) in AST (siDMT1 AST) or treating AST with Fe3+ chelator deferoxamine (DFX; DFX AST). siDMT1 AST showed no changes in proliferation but remained immature. Co-cultures of oligodendrocyte precursors cells (OPC) with siDMT1 AST and OPC cultures incubated with siDMT1 AST-conditioned media (ACM) rendered a reduction in OPC maturation. These findings correlated with a decrease in the expression of AST-secreted factors IGF-1, NRG-1, and LIF, known to promote OPC differentiation. siDMT1 AST also displayed increased mitochondrial number and reduced mitochondrial size as compared to control cells. DFX AST also remained immature and DFX AST-conditioned media also hampered OPC maturation in culture, in keeping with a decrease in the expression of AST-secreted growth factors IGF-1, NRG-1, LIF, and CNTF. DFX AST mitochondrial morphology and number showed results similar to those observed in siDMT1 AST. In sum, our results show that ID, induced through two different methods, impacts AST maturation and mitochondrial functioning, which in turn hampers OPC differentiation.
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Affiliation(s)
- María Silvina Marcora
- Departamento de Química Biológica e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Vanesa Soledad Mattera
- Departamento de Química Biológica e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Pilar Goñi
- Departamento de Química Biológica e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Florencia Aybar
- Departamento de Química Biológica e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Jorge Daniel Correale
- Departamento de Neurología, Fleni e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
| | - Juana Maria Pasquini
- Departamento de Química Biológica e Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina
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6
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Marty-Lombardi S, Lu S, Ambroziak W, Schrenk-Siemens K, Wang J, DePaoli-Roach AA, Hagenston AM, Wende H, Tappe-Theodor A, Simonetti M, Bading H, Okun JG, Kuner R, Fleming T, Siemens J. Neuron-astrocyte metabolic coupling facilitates spinal plasticity and maintenance of inflammatory pain. Nat Metab 2024; 6:494-513. [PMID: 38443593 DOI: 10.1038/s42255-024-01001-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/31/2024] [Indexed: 03/07/2024]
Abstract
Long-lasting pain stimuli can trigger maladaptive changes in the spinal cord, reminiscent of plasticity associated with memory formation. Metabolic coupling between astrocytes and neurons has been implicated in neuronal plasticity and memory formation in the central nervous system, but neither its involvement in pathological pain nor in spinal plasticity has been tested. Here we report a form of neuroglia signalling involving spinal astrocytic glycogen dynamics triggered by persistent noxious stimulation via upregulation of the Protein Targeting to Glycogen (PTG) in spinal astrocytes. PTG drove glycogen build-up in astrocytes, and blunting glycogen accumulation and turnover by Ptg gene deletion reduced pain-related behaviours and promoted faster recovery by shortening pain maintenance in mice. Furthermore, mechanistic analyses revealed that glycogen dynamics is a critically required process for maintenance of pain by facilitating neuronal plasticity in spinal lamina 1 neurons. In summary, our study describes a previously unappreciated mechanism of astrocyte-neuron metabolic communication through glycogen breakdown in the spinal cord that fuels spinal neuron hyperexcitability.
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Affiliation(s)
| | - Shiying Lu
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Oliver Wyman GmbH, Munich, Germany
| | - Wojciech Ambroziak
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Department of Translational Disease Understanding, Grünenthal GmbH, Aachen, Germany
| | | | - Jialin Wang
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anna M Hagenston
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Hagen Wende
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Taconic Biosciences, Leverkusen, Germany
| | | | - Manuela Simonetti
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Hilmar Bading
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Jürgen G Okun
- Dietmar-Hopp-Metabolic Center, Division of Neuropaediatrics and Metabolic Medicine, Heidelberg University, Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Thomas Fleming
- Department of Endocrinology, Diabetology, Metabolism and Clinical Chemistry (Internal Medicine 1), Heidelberg University Hospital, Heidelberg, Germany
- German Center of Diabetes Research (DZD), Neuherberg, Germany
| | - Jan Siemens
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.
- Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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7
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Mitra S, Chen B, Shelton JM, Nitschke S, Wu J, Covington L, Dear M, Lynn T, Verma M, Nitschke F, Fuseya Y, Iwai K, Evers BM, Minassian BA. Myofiber-type-dependent 'boulder' or 'multitudinous pebble' formations across distinct amylopectinoses. Acta Neuropathol 2024; 147:46. [PMID: 38411740 DOI: 10.1007/s00401-024-02698-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/13/2024] [Accepted: 01/24/2024] [Indexed: 02/28/2024]
Abstract
At least five enzymes including three E3 ubiquitin ligases are dedicated to glycogen's spherical structure. Absence of any reverts glycogen to a structure resembling amylopectin of the plant kingdom. This amylopectinosis (polyglucosan body formation) causes fatal neurological diseases including adult polyglucosan body disease (APBD) due to glycogen branching enzyme deficiency, Lafora disease (LD) due to deficiencies of the laforin glycogen phosphatase or the malin E3 ubiquitin ligase and type 1 polyglucosan body myopathy (PGBM1) due to RBCK1 E3 ubiquitin ligase deficiency. Little is known about these enzymes' functions in glycogen structuring. Toward understanding these functions, we undertake a comparative murine study of the amylopectinoses of APBD, LD and PGBM1. We discover that in skeletal muscle, polyglucosan bodies form as two main types, small and multitudinous ('pebbles') or giant and single ('boulders'), and that this is primarily determined by the myofiber types in which they form, 'pebbles' in glycolytic and 'boulders' in oxidative fibers. This pattern recapitulates what is known in the brain in LD, innumerable dust-like in astrocytes and single giant sized in neurons. We also show that oxidative myofibers are relatively protected against amylopectinosis, in part through highly increased glycogen branching enzyme expression. We present evidence of polyglucosan body size-dependent cell necrosis. We show that sex influences amylopectinosis in genotype, brain region and myofiber-type-specific fashion. RBCK1 is a component of the linear ubiquitin chain assembly complex (LUBAC), the only known cellular machinery for head-to-tail linear ubiquitination critical to numerous cellular pathways. We show that the amylopectinosis of RBCK1 deficiency is not due to loss of linear ubiquitination, and that another function of RBCK1 or LUBAC must exist and operate in the shaping of glycogen. This work opens multiple new avenues toward understanding the structural determinants of the mammalian carbohydrate reservoir critical to neurologic and neuromuscular function and disease.
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Affiliation(s)
- Sharmistha Mitra
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA.
| | - Baozhi Chen
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - John M Shelton
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9148, USA
| | - Silvia Nitschke
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Jun Wu
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Lindsay Covington
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9148, USA
| | - Mathew Dear
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Tori Lynn
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Mayank Verma
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Felix Nitschke
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA
| | - Yasuhiro Fuseya
- Department of Molecular and Cellular Physiology, Kyoto University School of Medicine, Kyoto, 606-8501, Japan
| | - Kazuhiro Iwai
- Department of Molecular and Cellular Physiology, Kyoto University School of Medicine, Kyoto, 606-8501, Japan
| | - Bret M Evers
- Departments of Pathology and Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-9073, USA
| | - Berge A Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9063, USA.
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8
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Delgado MG, Delgado R. Transient Synaptic Enhancement Triggered by Exogenously Supplied Monocarboxylate in Drosophila Motoneuron Synapse. Neuroscience 2024; 539:66-75. [PMID: 38220128 DOI: 10.1016/j.neuroscience.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/16/2024]
Abstract
Current evidence suggests that glial cells provide C3 carbon sources to fuel neuronal activity; however, this notion has become challenged by biosensor studies carried out in acute brain slices or in vivo, showing that neuronal activity does not rely on the import of astrocyte-produced L-lactate. Rather, stimulated neurons become net lactate exporters, as it was also shown in Drosophila neurons, in which astrocyte-provided lactate returns as lipid droplets to be stored in glial cells. In this view, we investigate whether exogenously supplied monocarboxylates can support Drosophila motoneuron neurotransmitter release (NTR). By assessing the excitatory post-synaptic current (EPSC) amplitude under voltage-clamp as NTR indicative, we found that both pyruvate and L-lactate, as the only carbon sources in the synapses bathing-solution, cause a large transient NTR enhancement, which declines to reach a synaptic depression state, from which the synapses do not recover. The FM1-43 pre-synaptic loading ability, however, is maintained under monocarboxylate, suggesting that SV cycling should not contribute to the synaptic depression state. The NTR recovery was reached by supplementing the monocarboxylate medium with sucrose. However, monocarboxylate addition to sucrose medium does not enhance NTR, but it does when the disaccharide concentration becomes too reduced. Thus, when pyruvate concentrations become too reduced, exogenously supplied L-lactate could be converted to pyruvate and metabolized by the neural mitochondria, triggering the NTR enhancement. SIGNIFICANCE STATEMENT: The question of whether monocarboxylic acids can fuel the Drosophila motoneuron NTR was challenged. Our findings show that exogenously supplied monocarboxylates trigger a large transient synaptic enhancement just under extreme glycolysis reduction but fail to maintain NTR under sustained synaptic demand, still at low frequency stimulation, driven to the synapses to a synaptic depression state. Glycolysis activation, by adding sucrose to the monocarboxylate bath solution, restores the motoneuron NTR ability, giving place to a hexoses role in SV recruitment. Moreover these results suggest exogenously supplied C3 carbon sources could have an additional role beyond providing energetic support for neural activity.
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Affiliation(s)
- María-Graciela Delgado
- Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras 3425, 7800001 Santiago, Chile.
| | - Ricardo Delgado
- Department of Biology, Faculty of Sciences, University of Chile, Las Palmeras 3425, 7800001 Santiago, Chile.
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9
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Azevedo M, Martinho R, Oliveira A, Correia-de-Sá P, Moreira-Rodrigues M. Molecular pathways underlying sympathetic autonomic overshooting leading to fear and traumatic memories: looking for alternative therapeutic options for post-traumatic stress disorder. Front Mol Neurosci 2024; 16:1332348. [PMID: 38260808 PMCID: PMC10800988 DOI: 10.3389/fnmol.2023.1332348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024] Open
Abstract
The sympathoadrenal medullary system and the hypothalamic-pituitary-adrenal axis are both activated upon stressful events. The release of catecholamines, such as dopamine, norepinephrine (NE), and epinephrine (EPI), from sympathetic autonomic nerves participate in the adaptive responses to acute stress. Most theories suggest that activation of peripheral β-adrenoceptors (β-ARs) mediates catecholamines-induced memory enhancement. These include direct activation of β-ARs in the vagus nerve, as well as indirect responses to catecholamine-induced glucose changes in the brain. Excessive sympathetic activity is deeply associated with memories experienced during strong emotional stressful conditions, with catecholamines playing relevant roles in fear and traumatic memories consolidation. Recent findings suggest that EPI is implicated in fear and traumatic contextual memories associated with post-traumatic stress disorder (PTSD) by increasing hippocampal gene transcription (e.g., Nr4a) downstream to cAMP response-element protein activation (CREB). Herein, we reviewed the literature focusing on the molecular mechanisms underlying the pathophysiology of memories associated with fear and traumatic experiences to pave new avenues for the treatment of stress and anxiety conditions, such as PTSD.
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Affiliation(s)
- Márcia Azevedo
- Laboratory of General Physiology, Department of Immuno-Physiology and Pharmacology and Center for Drug Discovery and Innovative Medicines (MedInUP), School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), Porto, Portugal
| | - Raquel Martinho
- Laboratory of General Physiology, Department of Immuno-Physiology and Pharmacology and Center for Drug Discovery and Innovative Medicines (MedInUP), School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), Porto, Portugal
| | - Ana Oliveira
- Laboratory of General Physiology, Department of Immuno-Physiology and Pharmacology and Center for Drug Discovery and Innovative Medicines (MedInUP), School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratory of Pharmacology and Neurobiology, Department of Immuno-Physiology and Pharmacology and Center for Drug Discovery and Innovative Medicines (MedInUP), School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), Porto, Portugal
| | - Mónica Moreira-Rodrigues
- Laboratory of General Physiology, Department of Immuno-Physiology and Pharmacology and Center for Drug Discovery and Innovative Medicines (MedInUP), School of Medicine and Biomedical Sciences (ICBAS), University of Porto (UP), Porto, Portugal
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10
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Zhang YM, Qi YB, Gao YN, Chen WG, Zhou T, Zang Y, Li J. Astrocyte metabolism and signaling pathways in the CNS. Front Neurosci 2023; 17:1217451. [PMID: 37732313 PMCID: PMC10507181 DOI: 10.3389/fnins.2023.1217451] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/18/2023] [Indexed: 09/22/2023] Open
Abstract
Astrocytes comprise half of the cells in the central nervous system and play a critical role in maintaining metabolic homeostasis. Metabolic dysfunction in astrocytes has been indicated as the primary cause of neurological diseases, such as depression, Alzheimer's disease, and epilepsy. Although the metabolic functionalities of astrocytes are well known, their relationship to neurological disorders is poorly understood. The ways in which astrocytes regulate the metabolism of glucose, amino acids, and lipids have all been implicated in neurological diseases. Metabolism in astrocytes has also exhibited a significant influence on neuron functionality and the brain's neuro-network. In this review, we focused on metabolic processes present in astrocytes, most notably the glucose metabolic pathway, the fatty acid metabolic pathway, and the amino-acid metabolic pathway. For glucose metabolism, we focused on the glycolysis pathway, pentose-phosphate pathway, and oxidative phosphorylation pathway. In fatty acid metabolism, we followed fatty acid oxidation, ketone body metabolism, and sphingolipid metabolism. For amino acid metabolism, we summarized neurotransmitter metabolism and the serine and kynurenine metabolic pathways. This review will provide an overview of functional changes in astrocyte metabolism and provide an overall perspective of current treatment and therapy for neurological disorders.
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Affiliation(s)
- Yong-mei Zhang
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ying-bei Qi
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ya-nan Gao
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Wen-gang Chen
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Ting Zhou
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yi Zang
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jia Li
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, Jiangsu, China
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11
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Balraj A, Clarkson-Paredes C, Miller RH. Loss of optic nerve oligodendrocytes during maturation alters retinal organization. Exp Eye Res 2023:109540. [PMID: 37364629 DOI: 10.1016/j.exer.2023.109540] [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: 02/28/2023] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023]
Abstract
The myelin sheath facilitates signal conduction along axons in white matter tracts, and when disrupted, can result in significant functional deficits. Demyelination, observed in diseases like multiple sclerosis and optic neuritis, are associated with neural degeneration, however the extent of this damage on upstream circuitry is not well understood. Here we use the MBP-iCP9 mouse model to induce selective oligodendrocyte ablation in the optic nerve at P14 via a chemical inducer of dimerization (CID), resulting in partial demyelination of retinal ganglion cell (RGC) axons with minimal inflammation after two weeks. Oligodendrocyte loss reduced axon diameter and altered compound action potential waveforms, blocking conduction in the slowest-conducting axon populations. Demyelination resulted in disruptions to the normal composition of the retina, including reduced density of RBPMS+, Brn3a+, and OFF-transient RGCs, thinning of the IPL, and reduced density of displaced amacrine cells. The INL and ONL were unaffected by oligodendrocyte loss, suggesting that demyelination-induced deficits in this model are specific to the IPL and GCL. These results show that a partial demyelination of a subpopulation of RGC axons disrupts optic nerve function and affects the organization of the retinal network. This study highlights the significance of myelination in maintaining upstream neural connectivity and provides support for targeting neuronal degeneration in treatments of demyelinating diseases.
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Affiliation(s)
- Annika Balraj
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA
| | - Cheryl Clarkson-Paredes
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA
| | - Robert H Miller
- Department of Anatomy and Cell Biology, The George Washington University, School of Medicine and Health Sciences, Washington, D.C., USA.
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12
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Zorec R, Vardjan N. Adrenergic regulation of astroglial aerobic glycolysis and lipid metabolism: Towards a noradrenergic hypothesis of neurodegeneration. Neurobiol Dis 2023; 182:106132. [PMID: 37094775 DOI: 10.1016/j.nbd.2023.106132] [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: 01/07/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 04/26/2023] Open
Abstract
Ageing is a key factor in the development of cognitive decline and dementia, an increasing and challenging problem of the modern world. The most commonly diagnosed cognitive decline is related to Alzheimer's disease (AD), the pathophysiology of which is poorly understood. Several hypotheses have been proposed. The cholinergic hypothesis is the oldest, however, recently the noradrenergic system has been considered to have a role as well. The aim of this review is to provide evidence that supports the view that an impaired noradrenergic system is causally linked to AD. Although dementia is associated with neurodegeneration and loss of neurons, this likely develops due to a primary failure of homeostatic cells, astrocytes, abundant and heterogeneous neuroglial cells in the central nervous system (CNS). The many functions that astrocytes provide to maintain the viability of neural networks include the control of ionic balance, neurotransmitter turnover, synaptic connectivity and energy balance. This latter function is regulated by noradrenaline, released from the axon varicosities of neurons arising from the locus coeruleus (LC), the primary site of noradrenaline release in the CNS. The demise of the LC is linked to AD, whereby a hypometabolic CNS state is observed clinically. This is likely due to impaired release of noradrenaline in the AD brain during states of arousal, attention and awareness. These functions controlled by the LC are needed for learning and memory formation and require activation of the energy metabolism. In this review, we address first the process of neurodegeneration and cognitive decline, highlighting the function of astrocytes. Cholinergic and/or noradrenergic deficits lead to impaired astroglial function. Then, we focus on adrenergic control of astroglial aerobic glycolysis and lipid droplet metabolism, which play a protective role but also promote neurodegeneration under some circumstances, supporting the noradrenergic hypothesis of cognitive decline. We conclude that targeting astroglial metabolism, glycolysis and/or mitochondrial processes may lead to important new developments in the future when searching for medicines to prevent or even halt cognitive decline.
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Affiliation(s)
- Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia.
| | - Nina Vardjan
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia.
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13
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Roumes H, Pellerin L, Bouzier-Sore AK. Astrocytes as metabolic suppliers to support neuronal activity and brain functions. Essays Biochem 2023; 67:27-37. [PMID: 36504117 PMCID: PMC10011397 DOI: 10.1042/ebc20220080] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022]
Abstract
Energy metabolism is essential for brain function. In recent years, lactate shuttling between astrocytes and neurons has become a fundamental concept of neuroenergetics. However, it remains unclear to what extent this process is critical for different aspects of cognition, their underlying mechanisms, as well as for the signals used to monitor brain activation.
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Affiliation(s)
- Hélène Roumes
- Univ. Bordeaux, CNRS, CRMSB, UMR 5536, F-33000 Bordeaux, France
| | - Luc Pellerin
- Univ. Poitiers and CHU Poitiers, IRMETIST, INSERM U1313, F-86021 Poitiers, France
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14
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Gao C, Yang B, Li Y, Pei W. A monocarboxylate transporter-dependent mechanism confers resistance to exercise-induced fatigue in a high-altitude hypoxic environment. Sci Rep 2023; 13:2949. [PMID: 36807596 PMCID: PMC9941081 DOI: 10.1038/s41598-023-30093-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
The body is more prone to fatigue in a high-altitude hypoxic environment, in which fatigue occurs in both peripheral muscles and the central nervous system (CNS). The key factor determining the latter is the imbalance in brain energy metabolism. During strenuous exercise, lactate released from astrocytes is taken up by neurons via monocarboxylate transporters (MCTs) as a substrate for energy metabolism. The present study investigated the correlations among the adaptability to exercise-induced fatigue, brain lactate metabolism and neuronal hypoxia injury in a high-altitude hypoxic environment. Rats were subjected to exhaustive incremental load treadmill exercise under either normal pressure and normoxic conditions or simulated high-altitude, low-pressure and hypoxic conditions, with subsequent evaluation of the average exhaustive time as well as the expression of MCT2 and MCT4 in the cerebral motor cortex, the average neuronal density in the hippocampus, and the brain lactate content. The results illustrate that the average exhaustive time, neuronal density, MCT expression and brain lactate content were positively correlated with the altitude acclimatization time. These findings demonstrate that an MCT-dependent mechanism is involved in the adaptability of the body to central fatigue and provide a potential basis for medical intervention for exercise-induced fatigue in a high-altitude hypoxic environment.
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Affiliation(s)
- Chen Gao
- Department of General Practice, The 940Th Hospital of Joint Logistics Support Force of Chinese People's Liberation Army, BinHe South Road, No.333, Lanzhou, 730050, Gansu, China.
| | - Binni Yang
- Department of General Practice, The 940Th Hospital of Joint Logistics Support Force of Chinese People’s Liberation Army, BinHe South Road, No.333, Lanzhou, 730050 Gansu China
| | - Yurong Li
- Department of General Practice, The 940Th Hospital of Joint Logistics Support Force of Chinese People’s Liberation Army, BinHe South Road, No.333, Lanzhou, 730050 Gansu China
| | - Wenjuan Pei
- Department of General Practice, The 940Th Hospital of Joint Logistics Support Force of Chinese People’s Liberation Army, BinHe South Road, No.333, Lanzhou, 730050 Gansu China
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15
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Kuhlmann T, Moccia M, Coetzee T, Cohen JA, Correale J, Graves J, Marrie RA, Montalban X, Yong VW, Thompson AJ, Reich DS. Multiple sclerosis progression: time for a new mechanism-driven framework. Lancet Neurol 2023; 22:78-88. [PMID: 36410373 PMCID: PMC10463558 DOI: 10.1016/s1474-4422(22)00289-7] [Citation(s) in RCA: 184] [Impact Index Per Article: 184.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/29/2022] [Accepted: 06/29/2022] [Indexed: 11/20/2022]
Abstract
Traditionally, multiple sclerosis has been categorised by distinct clinical descriptors-relapsing-remitting, secondary progressive, and primary progressive-for patient care, research, and regulatory approval of medications. Accumulating evidence suggests that the clinical course of multiple sclerosis is better considered as a continuum, with contributions from concurrent pathophysiological processes that vary across individuals and over time. The apparent evolution to a progressive course reflects a partial shift from predominantly localised acute injury to widespread inflammation and neurodegeneration, coupled with failure of compensatory mechanisms, such as neuroplasticity and remyelination. Ageing increases neural susceptibility to injury and decreases resilience. These observations encourage a new consideration of the course of multiple sclerosis as a spectrum defined by the relative contributions of overlapping pathological and reparative or compensatory processes. New understanding of key mechanisms underlying progression and measures to quantify progressive pathology will potentially have important and beneficial implications for clinical care, treatment targets, and regulatory decision-making.
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Affiliation(s)
- Tanja Kuhlmann
- Institute of Neuropathology, University Hospital Münster, Münster, Germany; Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
| | - Marcello Moccia
- Multiple Sclerosis Clinical Care and Research Centre, Department of Neurosciences, Federico II University of Naples, Naples, Italy
| | - Timothy Coetzee
- National Multiple Sclerosis Society (USA), New York, NY, USA
| | - Jeffrey A Cohen
- Department of Neurology, Mellen Center for Multiple Sclerosis Treatment and Research, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jorge Correale
- Fleni, Department of Neurology, Buenos Aires, Argentina; Institute of Biological Chemistry and Biophysics (IQUIFIB), CONICET/UBA, Buenos Aires, Argentina
| | - Jennifer Graves
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Ruth Ann Marrie
- Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Xavier Montalban
- Multiple Sclerosis Centre of Catalonia and Department of Neurology-Neuroimmunology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - V Wee Yong
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Alan J Thompson
- Queen Square Multiple Sclerosis Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, NIHR University College London Hospitals Biomedical Research Centre, Faculty of Brain Sciences, University College London, London, UK
| | - Daniel S Reich
- Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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16
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Zhang M, Wang Y, Bai Y, Dai L, Guo H. Monocarboxylate Transporter 1 May Benefit Cerebral Ischemia via Facilitating Lactate Transport From Glial Cells to Neurons. Front Neurol 2022; 13:781063. [PMID: 35547368 PMCID: PMC9081727 DOI: 10.3389/fneur.2022.781063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Monocarboxylate transporter 1 (MCT1) is expressed in glial cells and some populations of neurons. MCT1 facilitates astrocytes or oligodendrocytes (OLs) in the energy supplement of neurons, which is crucial for maintaining the neuronal activity and axonal function. It is suggested that MCT1 upregulation in cerebral ischemia is protective to ischemia/reperfusion (I/R) injury. Otherwise, its underlying mechanism has not been clearly discussed. In this review, it provides a novel insight that MCT1 may protect brain from I/R injury via facilitating lactate transport from glial cells (such as, astrocytes and OLs) to neurons. It extensively discusses (1) the structure and localization of MCT1; (2) the regulation of MCT1 in lactate transport among astrocytes, OLs, and neurons; and (3) the regulation of MCT1 in the cellular response of lactate accumulation under ischemic attack. At last, this review concludes that MCT1, in cerebral ischemia, may improve lactate transport from glial cells to neurons, which subsequently alleviates cellular damage induced by lactate accumulation (mostly in glial cells), and meets the energy metabolism of neurons.
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Affiliation(s)
- Mao Zhang
- Department of Medical Genetics, College of Basic Medical Sciences, Army Medical University, Chongqing, China
| | - Yanyan Wang
- Department of Medical Genetics, College of Basic Medical Sciences, Army Medical University, Chongqing, China
| | - Yun Bai
- Department of Medical Genetics, College of Basic Medical Sciences, Army Medical University, Chongqing, China
| | - Limeng Dai
- Department of Medical Genetics, College of Basic Medical Sciences, Army Medical University, Chongqing, China
| | - Hong Guo
- Department of Medical Genetics, College of Basic Medical Sciences, Army Medical University, Chongqing, China
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17
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Babcock KJ, Abdolmohammadi B, Kiernan PT, Mahar I, Cherry JD, Alvarez VE, Goldstein LE, Stein TD, McKee AC, Huber BR. Interface astrogliosis in contact sport head impacts and military blast exposure. Acta Neuropathol Commun 2022; 10:52. [PMID: 35418116 PMCID: PMC9009003 DOI: 10.1186/s40478-022-01358-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/29/2022] [Indexed: 12/11/2022] Open
Abstract
Exposure to military blast and repetitive head impacts (RHI) in contact sports is associated with increased risk of long-term neurobehavioral sequelae and cognitive deficits, and the neurodegenerative disease chronic traumatic encephalopathy (CTE). At present, the exact pathogenic mechanisms of RHI and CTE are unknown, and no targeted therapies are available. Astrocytes have recently emerged as key mediators of the multicellular response to head trauma. Here, we investigated interface astrogliosis in blast and impact neurotrauma, specifically in the context of RHI and early stage CTE. We compared postmortem brain tissue from former military veterans with a history of blast exposure with and without a neuropathological diagnosis of CTE, former American football players with a history of RHI with and without a neuropathological diagnosis of CTE, and control donors without a history of blast, RHI exposure or CTE diagnosis. Using quantitative immunofluorescence, we found that astrogliosis was higher at the grey-white matter interface in the dorsolateral frontal cortex, with mixed effects at the subpial surface and underlying cortex, in both blast and RHI donors with and without CTE, compared to controls. These results indicate that certain astrocytic alterations are associated with both impact and blast neurotrauma, and that different astroglial responses take place in distinct brain regions.
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18
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Wang Y, Peng Y, Zhang C, Zhou X. Astrocyte-neuron lactate transport in the ACC contributes to the occurrence of long-lasting inflammatory pain in male mice. Neurosci Lett 2021; 764:136205. [PMID: 34478818 DOI: 10.1016/j.neulet.2021.136205] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/24/2021] [Accepted: 08/29/2021] [Indexed: 12/20/2022]
Abstract
Lactate transport is an important means of communication between astrocytes and neurons and is implicated in a variety of neurobiological processes. However, the connection between astrocyte-neuron lactate transport and nociceptive modulation has not been well established. Here, we found that Complete Freund's adjuvant (CFA)-induced inflammation pain leads to a significant increase in extracellular lactate levels in the anterior cingulate cortex (ACC). Inhibition of glycogenolysis and lactate release in the ACC disrupted the persistent, but not acute, inflammation pain induced by CFA, and this effect was reversed by exogenous L-lactate administration. Knocking down the expression of lactate transporters (MCT1, MCT4, or MCT2) also disrupted the long lasting inflammation pain induced by CFA. Moreover, glycogenolysis in the ACC is critical for the induction of molecular changes related to neuronal plasticity, including the induction of phospho- (p-) ERK, p-CREB, and Fos. Taken together, our findings indicate that astrocyte-neuron lactate transport in the ACC is critical for the occurrence of persistent inflammation pain, suggesting a novel mechanism underlying chronic pain.
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Affiliation(s)
- Yin Wang
- Department of Anesthesiology, Taizhou People's Hospital, Taizhou, Jiangsu, China
| | - Yunan Peng
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Chenjing Zhang
- Department of Anesthesiology, Taizhou People's Hospital, Taizhou, Jiangsu, China
| | - Xuelong Zhou
- Department of Anesthesiology and Perioperative Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
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19
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Huang Z, Zhang Y, Zhou R, Yang L, Pan H. Lactate as Potential Mediators for Exercise-Induced Positive Effects on Neuroplasticity and Cerebrovascular Plasticity. Front Physiol 2021; 12:656455. [PMID: 34290615 PMCID: PMC8287254 DOI: 10.3389/fphys.2021.656455] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 06/09/2021] [Indexed: 01/22/2023] Open
Abstract
The accumulated evidence from animal and human studies supports that exercise is beneficial to physical health. Exercise can upregulate various neurotrophic factors, activate neuroplasticity, and play a positive role in improving and enhancing cerebrovascular function. Due to its economy, convenience, and ability to prevent or ameliorate various aging-related diseases, exercise, a healthy lifestyle, is increasingly popularized by people. However, the mechanism by which exercise performs this function and how it is transmitted from muscles to the brain remains incompletely understood. Here, we review the beneficial effects of exercise with different intensities on the brain with a focus on the positive effects of lactate on neuroplasticity and cerebrovascular plasticity. Based on these recent studies, we propose that lactate, a waste previously misunderstood as a by-product of glycolysis in the past, may be a key signal molecule that regulates the beneficial adaptation of the brain caused by exercise. Importantly, we speculate that a central protective mechanism may underlie the cognitive benefits induced by exercise.
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Affiliation(s)
- Zhihai Huang
- Cognitive and Sports Neuroscience Laboratory, National Demonstration Center for Experimental Sports Science Education, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China
| | - Yulan Zhang
- Cognitive and Sports Neuroscience Laboratory, National Demonstration Center for Experimental Sports Science Education, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China
| | - Ruixue Zhou
- Cognitive and Sports Neuroscience Laboratory, National Demonstration Center for Experimental Sports Science Education, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China
| | - Luodan Yang
- Cognitive and Sports Neuroscience Laboratory, National Demonstration Center for Experimental Sports Science Education, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China
| | - Hongying Pan
- Cognitive and Sports Neuroscience Laboratory, National Demonstration Center for Experimental Sports Science Education, College of Physical Education and Sports Science, South China Normal University, Guangzhou, China
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20
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Sun L, Min L, Li M, Shao F. Juvenile social isolation leads to schizophrenia-like behaviors via excess lactate production by astrocytes. Brain Res Bull 2021; 174:240-249. [PMID: 34175384 DOI: 10.1016/j.brainresbull.2021.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/02/2021] [Accepted: 06/22/2021] [Indexed: 01/10/2023]
Abstract
Repeated early environmental deprivation is regarded as a typical paradigm to mimic the behavioral abnormalities and brain dysfunction that occur in psychiatric disorders. Previously, we reported that social isolation could disrupt prepulse inhibition (PPI) in Sprague-Dawley (SD) rats, producing the typical characteristics of a schizophrenia animal model. Based on further analysis of previous proteomic and transcriptomic data, a disrupted balance of glucose metabolism was found in the prefrontal cortex (PFC) of isolated rats. Subsequently, in the first experiment of this study, we investigated the effects of juvenile social isolation (postnatal days (PND) 21-34) on PPI and lactate levels in PND56 rats. Compared with the social rearing group, rats in the isolated rearing group showed disrupted PPI and increased lactate levels in the PFC. In the second experiment, at PND55, the model rats were acutely injected with a glycogen phosphorylase inhibitor (4-dideoxy-1,4-imino-darabinitol, DAB) or control saline in the bilateral PFC. Our data showed that acute DAB administration (50 pmol, 0.5 μl) significantly improved the disrupted PPI and decreased the levels of oxidative phosphorylation (OXPHOS)-related mRNAs as well as lactate. In summary, our results suggested that excess astrocytic lactate production was involved in the impairment of auditory sensory gating of isolated rats, which may contribute to the metabolic pathogenesis of schizophrenia.
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Affiliation(s)
- Lan Sun
- Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense Technology, Academy of Military Sciences, Beijing, 100071, China; School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, 100871, China
| | - Li Min
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Man Li
- Faculty of Psychology, Tianjin Normal University, Tianjin, 300387, China
| | - Feng Shao
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, 100871, China.
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21
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Abstract
Animal behavior was classically considered to be determined exclusively by neuronal activity, whereas surrounding glial cells such as astrocytes played only supportive roles. However, astrocytes are as numerous as neurons in the mammalian brain, and current findings indicate a chemically based dialog between astrocytes and neurons. Activation of astrocytes by synaptically released neurotransmitters converges on regulating intracellular Ca2+ in astrocytes, which then can regulate the efficacy of near and distant tripartite synapses at diverse timescales through gliotransmitter release. Here, we discuss recent evidence on how diverse behaviors are impacted by this dialog. These recent findings support a paradigm shift in neuroscience, in which animal behavior does not result exclusively from neuronal activity but from the coordinated activity of both astrocytes and neurons. Decoding how astrocytes and neurons interact with each other in various brain circuits will be fundamental to fully understanding how behaviors originate and become dysregulated in disease.
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Affiliation(s)
- Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA;
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA;
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22
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Li S, Bianconi S, van der Veen JW, Do AD, Stolinski J, Cecil KM, Hannah-Shmouni F, Porter FD, Shen J. Oxidative phosphorylation in creatine transporter deficiency. NMR IN BIOMEDICINE 2021; 34:e4419. [PMID: 32990357 PMCID: PMC7722185 DOI: 10.1002/nbm.4419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
X-linked creatine transporter deficiency (CTD) is one of the three types of cerebral creatine deficiency disorders. CTD arises from pathogenic variants in the X-linked gene SLC6A8. We report the first phosphorus (31 P) MRS study of patients with CTD, where both phosphocreatine and total creatine concentrations were found to be markedly reduced. Despite the diminished role of creatine and phosphocreatine in oxidative phosphorylation in CTD, we found no elevation of lactate or lowered pH, indicating that the brain energy supply still largely relied on oxidative metabolism. Our results suggest that mitochondrial function is a potential therapeutic target for CTD.
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Affiliation(s)
- Shizhe Li
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Simona Bianconi
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | | | - An Dang Do
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - JoEllyn Stolinski
- NMR Facility, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Kim M. Cecil
- Department of Radiology, Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Fady Hannah-Shmouni
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Forbes D. Porter
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Jun Shen
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
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23
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Park SJ, Choi JW. Brain energy metabolism and multiple sclerosis: progress and prospects. Arch Pharm Res 2020; 43:1017-1030. [PMID: 33119885 DOI: 10.1007/s12272-020-01278-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
Multiple sclerosis (MS) is an autoimmune disease accompanied with nerve pain and paralysis. Although various pathogenic causes of MS have been suggested, including genetic and environmental factors, how MS occurs remains unclear. Moreover, MS should be diagnosed based on clinical experiences because of no disease-specific biomarker and currently available treatments for MS just can reduce relapsing frequency or severity with little effects on disease disability. Therefore, more efforts are required to identify pathophysiology of MS and diagnosis markers. Recent evidence indicates another aspect of MS pathogenesis, energy failure in the central nervous system (CNS). For instance, inflammation that is a characteristic MS symptom and occurs frequently in the CNS of MS patients can result into energy failure in mitochondria and cytosol. Indeed, metabolomics studies for MS have reported energy failure in oxidative phosphorylation and alteration of aerobic glycolysis. Therefore, studies on the metabolism in the CNS may provide another insight for understanding complexity of MS and pathogenesis, which would facilitate the discovery of promising strategies for developing therapeutics to treat MS. This review will provide an overview on recent progress of metabolomic studies for MS, with a focus on the fluctuation of energy metabolism in MS.
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Affiliation(s)
- Sung Jean Park
- College of Pharmacy and Gachon Institute of Pharmaceutical Sciences, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Korea.
| | - Ji Woong Choi
- College of Pharmacy and Gachon Institute of Pharmaceutical Sciences, Gachon University, 191 Hambakmoero, Yeonsu-gu, Incheon, 21936, Korea.
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24
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Jha MK, Morrison BM. Lactate Transporters Mediate Glia-Neuron Metabolic Crosstalk in Homeostasis and Disease. Front Cell Neurosci 2020; 14:589582. [PMID: 33132853 PMCID: PMC7550678 DOI: 10.3389/fncel.2020.589582] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/09/2020] [Indexed: 12/28/2022] Open
Abstract
Research over the last couple of decades has provided novel insights into lactate neurobiology and the implications of lactate transport-driven neuroenergetics in health and diseases of peripheral nerve and the brain. The expression pattern of lactate transporters in glia and neurons has now been described, though notable controversies and discrepancies remain. Importantly, down- and up-regulation experiments are underway to better understand the function of these transporters in different systems. Lactate transporters in peripheral nerves are important for maintenance of axon and myelin integrity, motor end-plate integrity, the development of diabetic peripheral neuropathy (DPN), and the functional recovery following nerve injuries. Similarly, brain energy metabolism and functions ranging from development to synaptic plasticity to axonal integrity are also dependent on lactate transport primarily between glia and neurons. This review is focused on critically analysing the expression pattern and the functions of lactate transporters in peripheral nerves and the brain and highlighting their role in glia-neuron metabolic crosstalk in physiological and pathological conditions.
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Affiliation(s)
- Mithilesh Kumar Jha
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Brett M Morrison
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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25
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Astrocyte-Derived Lactate Modulates the Passive Coping Response to Behavioral Challenge in Male Mice. Neurosci Bull 2020; 37:1-14. [PMID: 32785834 DOI: 10.1007/s12264-020-00553-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023] Open
Abstract
Every organism inevitably experiences stress. In the face of acute, intense stress, for example, periods of passivity occur when an organism's actions fail to overcome the challenge. The occurrence of inactive behavior may indicate that struggling would most likely be fruitless. Repeated serious stress has been associated with mood disorders such as depression. The modulation of passive coping response patterns has been explored with a focus on the circuit level. However, the cellular and molecular mechanisms are largely uncharacterized. Here, we report that lactate is a key factor in the astrocytic modulation of the passive coping response to behavioral challenge in adult mice. We found increased extracellular lactate in the medial prefrontal cortex (mPFC) when mice experienced the forced swimming test (FST). Furthermore, we discovered that disturbing astrocytic glycogenolysis, which is a key step for lactate production in the mPFC, decreased the duration of immobility in the FST. Knocking down monocarboxylate transporter 4 (MCT4), which is expressed exclusively in astrocytes and transports lactate from astrocytes to the extracellular space, caused similar results in the FST. The behavioral effect of both the pharmacological disturbance of astrocytic glycogenolysis and viral disruption of MCT4 expression was rescued via the administration of L-lactate. Moreover, we found that both pharmacological and viral modulation of astrocyte-derived lactate in mPFC slices increased the excitability of layer V pyramidal neurons, and this enhancement was reversed by exogenous L-lactate administration. These results highlight astrocyte-derived lactate as a biological mechanism underlying the passive coping response to behavioral challenge and may provide new strategies to prevent mood disorders.
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26
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Maffezzini C, Calvo-Garrido J, Wredenberg A, Freyer C. Metabolic regulation of neurodifferentiation in the adult brain. Cell Mol Life Sci 2020; 77:2483-2496. [PMID: 31912194 PMCID: PMC7320050 DOI: 10.1007/s00018-019-03430-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/14/2019] [Accepted: 12/18/2019] [Indexed: 12/14/2022]
Abstract
Understanding the mechanisms behind neurodifferentiation in adults will be an important milestone in our quest to identify treatment strategies for cognitive disorders observed during our natural ageing or disease. It is now clear that the maturation of neural stem cells to neurones, fully integrated into neuronal circuits requires a complete remodelling of cellular metabolism, including switching the cellular energy source. Mitochondria are central for this transition and are increasingly seen as the regulatory hub in defining neural stem cell fate and neurodevelopment. This review explores our current knowledge of metabolism during adult neurodifferentiation.
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Affiliation(s)
- Camilla Maffezzini
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Stem Cell and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Javier Calvo-Garrido
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden.
| | - Christoph Freyer
- Max Planck Institute Biology of Ageing-Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden.
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27
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Stok M, de Boer H, Huston MW, Jacobs EH, Roovers O, Visser TP, Jahr H, Duncker DJ, van Deel ED, Reuser AJJ, van Til NP, Wagemaker G. Lentiviral Hematopoietic Stem Cell Gene Therapy Corrects Murine Pompe Disease. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 17:1014-1025. [PMID: 32462050 PMCID: PMC7240064 DOI: 10.1016/j.omtm.2020.04.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/27/2020] [Indexed: 01/07/2023]
Abstract
Pompe disease is an autosomal recessive lysosomal storage disorder characterized by progressive muscle weakness. The disease is caused by mutations in the acid α-glucosidase (GAA) gene. Despite the currently available enzyme replacement therapy (ERT), roughly half of the infants with Pompe disease die before the age of 3 years. Limitations of ERT are immune responses to the recombinant enzyme, incomplete correction of the disease phenotype, lifelong administration, and inability of the enzyme to cross the blood-brain barrier. We previously reported normalization of glycogen in heart tissue and partial correction of the skeletal muscle phenotype by ex vivo hematopoietic stem cell gene therapy. In the present study, using a codon-optimized GAA (GAAco), the enzyme levels resulted in close to normalization of glycogen in heart, muscles, and brain, and in complete normalization of motor function. A large proportion of microglia in the brain was shown to be GAA positive. All astrocytes contained the enzyme, which is in line with mannose-6-phosphate receptor expression and the key role in glycogen storage and glucose metabolism. The lentiviral vector insertion site analysis confirmed no preference for integration near proto-oncogenes. This correction of murine Pompe disease warrants further development toward a cure of the human condition.
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Affiliation(s)
- Merel Stok
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Pediatrics, Erasmus University Medical Center, Rotterdam, the Netherlands.,Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Helen de Boer
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands.,Molecular Stem Cell Biology, Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Marshall W Huston
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Edwin H Jacobs
- Department of Molecular Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands.,Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Onno Roovers
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Trudi P Visser
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Holger Jahr
- Department of Orthopaedics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Dirk J Duncker
- Division of Experimental Cardiology, Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Elza D van Deel
- Division of Experimental Cardiology, Department of Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Arnold J J Reuser
- Center for Lysosomal and Metabolic Diseases, Erasmus University Medical Center, Rotterdam, the Netherlands.,Molecular Stem Cell Biology, Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Niek P van Til
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Gerard Wagemaker
- Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands
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28
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Famakin BM, Vemuganti R. Toll-Like Receptor 4 Signaling in Focal Cerebral Ischemia: a Focus on the Neurovascular Unit. Mol Neurobiol 2020; 57:2690-2701. [PMID: 32306272 DOI: 10.1007/s12035-020-01906-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/19/2020] [Indexed: 12/14/2022]
Abstract
A robust innate immune activation leads to downstream expression of inflammatory mediators that amplify tissue damage and consequently increase the morbidity after stroke. The Toll-like receptor 4 (TLR4) pathway is a major innate immune pathway activated acutely and chronically after stroke. Hence, understanding the intricacies of the temporal profile, specific control points, and cellular specificity of TLR4 activation is crucial for the development of any novel therapeutics targeting the endogenous innate immune response after focal cerebral ischemia. The goal of this review is to summarize the current findings related to TLR4 signaling after stroke with a specific focus on the components of the neurovascular unit such as astrocytes, neurons, endothelial cells, and pericytes. In addition, this review will examine the effects of focal cerebral ischemia on interaction of these neurovascular unit components.
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Affiliation(s)
| | - R Vemuganti
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
- William S. Middleton VA Hospital, Madison, WI, USA
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29
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Strohm L, Behrends C. Glia-specific autophagy dysfunction in ALS. Semin Cell Dev Biol 2020; 99:172-182. [DOI: 10.1016/j.semcdb.2019.05.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/30/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
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30
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Chamberlain KA, Sheng ZH. Mechanisms for the maintenance and regulation of axonal energy supply. J Neurosci Res 2019; 97:897-913. [PMID: 30883896 PMCID: PMC6565461 DOI: 10.1002/jnr.24411] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/04/2019] [Accepted: 02/18/2019] [Indexed: 12/25/2022]
Abstract
The unique polarization and high-energy demand of neurons necessitates specialized mechanisms to maintain energy homeostasis throughout the cell, particularly in the distal axon. Mitochondria play a key role in meeting axonal energy demand by generating adenosine triphosphate through oxidative phosphorylation. Recent evidence demonstrates how axonal mitochondrial trafficking and anchoring are coordinated to sense and respond to altered energy requirements. If and when these mechanisms are impacted in pathological conditions, such as injury and neurodegenerative disease, is an emerging research frontier. Recent evidence also suggests that axonal energy demand may be supplemented by local glial cells, including astrocytes and oligodendrocytes. In this review, we provide an updated discussion of how oxidative phosphorylation, aerobic glycolysis, and oligodendrocyte-derived metabolic support contribute to the maintenance of axonal energy homeostasis.
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Affiliation(s)
- Kelly Anne Chamberlain
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, Maryland 20892-3706, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, Maryland 20892-3706, USA
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31
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Descalzi G, Gao V, Steinman MQ, Suzuki A, Alberini CM. Lactate from astrocytes fuels learning-induced mRNA translation in excitatory and inhibitory neurons. Commun Biol 2019; 2:247. [PMID: 31286064 PMCID: PMC6606643 DOI: 10.1038/s42003-019-0495-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/05/2019] [Indexed: 12/12/2022] Open
Abstract
Glycogenolysis and lactate transport from astrocytes to neurons is required for long-term memory formation, but the role of this lactate is poorly understood. Here we show that the Krebs cycle substrates pyruvate and ketone body B3HB can functionally replace lactate in rescuing memory impairment caused by inhibition of glycogenolysis or expression knockdown of glia monocarboxylate transporters (MCTs) 1 and 4 in the dorsal hippocampus of rats. In contrast, either metabolite is unable to rescue memory impairment produced by expression knockdown of MCT2, which is selectively expressed by neurons, indicating that a critical role of astrocytic lactate is to provide energy for neuronal responses required for long-term memory. These responses include learning-induced mRNA translation in both excitatory and inhibitory neurons, as well as expression of Arc/Arg3.1. Thus, astrocytic lactate acts as an energy substrate to fuel learning-induced de novo neuronal translation critical for long-term memory.
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Affiliation(s)
- Giannina Descalzi
- Center for Neural Science, New York University, New York, NY 10003 USA
| | - Virginia Gao
- Center for Neural Science, New York University, New York, NY 10003 USA
| | | | - Akinobu Suzuki
- Center for Neural Science, New York University, New York, NY 10003 USA
- Present Address: Department of Biochemistry, Faculty of Medicine, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194 Japan
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32
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Verma V, Paul A, Amrapali Vishwanath A, Vaidya B, Clement JP. Understanding intellectual disability and autism spectrum disorders from common mouse models: synapses to behaviour. Open Biol 2019; 9:180265. [PMID: 31185809 PMCID: PMC6597757 DOI: 10.1098/rsob.180265] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Normal brain development is highly dependent on the timely coordinated actions of genetic and environmental processes, and an aberration can lead to neurodevelopmental disorders (NDDs). Intellectual disability (ID) and autism spectrum disorders (ASDs) are a group of co-occurring NDDs that affect between 3% and 5% of the world population, thus presenting a great challenge to society. This problem calls for the need to understand the pathobiology of these disorders and to design new therapeutic strategies. One approach towards this has been the development of multiple analogous mouse models. This review discusses studies conducted in the mouse models of five major monogenic causes of ID and ASDs: Fmr1, Syngap1, Mecp2, Shank2/3 and Neuroligins/Neurnexins. These studies reveal that, despite having a diverse molecular origin, the effects of these mutations converge onto similar or related aetiological pathways, consequently giving rise to the typical phenotype of cognitive, social and emotional deficits that are characteristic of ID and ASDs. This convergence, therefore, highlights common pathological nodes that can be targeted for therapy. Other than conventional therapeutic strategies such as non-pharmacological corrective methods and symptomatic alleviation, multiple studies in mouse models have successfully proved the possibility of pharmacological and genetic therapy enabling functional recovery.
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Affiliation(s)
- Vijaya Verma
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Abhik Paul
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Anjali Amrapali Vishwanath
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - Bhupesh Vaidya
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bengaluru 560 064, Karnataka, India
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33
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Thomas LW, Ashcroft M. Exploring the molecular interface between hypoxia-inducible factor signalling and mitochondria. Cell Mol Life Sci 2019; 76:1759-1777. [PMID: 30767037 PMCID: PMC6453877 DOI: 10.1007/s00018-019-03039-y] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 12/19/2022]
Abstract
Oxygen is required for the survival of the majority of eukaryotic organisms, as it is important for many cellular processes. Eukaryotic cells utilize oxygen for the production of biochemical energy in the form of adenosine triphosphate (ATP) generated from the catabolism of carbon-rich fuels such as glucose, lipids and glutamine. The intracellular sites of oxygen consumption-coupled ATP production are the mitochondria, double-membraned organelles that provide a dynamic and multifaceted role in cell signalling and metabolism. Highly evolutionarily conserved molecular mechanisms exist to sense and respond to changes in cellular oxygen levels. The primary transcriptional regulators of the response to decreased oxygen levels (hypoxia) are the hypoxia-inducible factors (HIFs), which play important roles in both physiological and pathophysiological contexts. In this review we explore the relationship between HIF-regulated signalling pathways and the mitochondria, including the regulation of mitochondrial metabolism, biogenesis and distribution.
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Affiliation(s)
- Luke W Thomas
- University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK
| | - Margaret Ashcroft
- University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK.
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34
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Aerobic Glycolysis Is Required for Spatial Memory Acquisition But Not Memory Retrieval in Mice. eNeuro 2019; 6:eN-NWR-0389-18. [PMID: 30809587 PMCID: PMC6390195 DOI: 10.1523/eneuro.0389-18.2019] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/23/2019] [Accepted: 01/26/2019] [Indexed: 12/18/2022] Open
Abstract
The consolidation of newly formed memories and their retrieval are energetically demanding processes. Aerobic glycolysis (AG), also known as the Warburg effect, consists of the production of lactate from glucose in the presence of oxygen. The astrocyte neuron lactate shuttle hypothesis posits that astrocytes process glucose by AG to generate lactate, which is used as a fuel source within neurons to maintain synaptic activity. Studies in mice have demonstrated that lactate transport between astrocytes and neurons is required for long-term memory formation, yet the role of lactate production in memory acquisition and retrieval has not previously been explored. Here, we examined the effect of dichloroacetate (DCA), a chemical inhibitor of lactate production, on spatial learning and memory in mice using the Morris water maze (MWM). In vivo hyperpolarized 13C-pyruvate magnetic resonance spectroscopy revealed decreased conversion of pyruvate to lactate in the mouse brain following DCA administration, concomitant with a reduction in the phosphorylation of pyruvate dehydrogenase. DCA exposure before each training session in the MWM impaired learning, which subsequently resulted in impaired memory during the probe trial. In contrast, mice that underwent training without DCA exposure, but received a single DCA injection before the probe trial exhibited normal memory. Our findings indicate that AG plays a key role during memory acquisition but is less important for the retrieval of established memories. Thus, the activation of AG may be important for learning-dependent synaptic plasticity rather than the activation of signaling cascades required for memory retrieval.
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35
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Correale J, Marrodan M, Ysrraelit MC. Mechanisms of Neurodegeneration and Axonal Dysfunction in Progressive Multiple Sclerosis. Biomedicines 2019; 7:biomedicines7010014. [PMID: 30791637 PMCID: PMC6466454 DOI: 10.3390/biomedicines7010014] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/14/2019] [Accepted: 02/18/2019] [Indexed: 12/14/2022] Open
Abstract
Multiple Sclerosis (MS) is a major cause of neurological disability, which increases predominantly during disease progression as a result of cortical and grey matter structures involvement. The gradual accumulation of disability characteristic of the disease seems to also result from a different set of mechanisms, including in particular immune reactions confined to the Central Nervous System such as: (a) B-cell dysregulation, (b) CD8+ T cells causing demyelination or axonal/neuronal damage, and (c) microglial cell activation associated with neuritic transection found in cortical demyelinating lesions. Other potential drivers of neurodegeneration are generation of oxygen and nitrogen reactive species, and mitochondrial damage, inducing impaired energy production, and intra-axonal accumulation of Ca2+, which in turn activates a variety of catabolic enzymes ultimately leading to progressive proteolytic degradation of cytoskeleton proteins. Loss of axon energy provided by oligodendrocytes determines further axonal degeneration and neuronal loss. Clearly, these different mechanisms are not mutually exclusive and could act in combination. Given the multifactorial pathophysiology of progressive MS, many potential therapeutic targets could be investigated in the future. This remains however, an objective that has yet to be undertaken.
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Affiliation(s)
- Jorge Correale
- Department of Neurology, FLENI, Buenos Aires 1428, Argentina.
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36
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Fingolimod Suppresses the Proinflammatory Status of Interferon-γ-Activated Cultured Rat Astrocytes. Mol Neurobiol 2019; 56:5971-5986. [PMID: 30701416 DOI: 10.1007/s12035-019-1481-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/10/2019] [Indexed: 12/14/2022]
Abstract
Astroglia, the primary homeostatic cells of the central nervous system, play an important role in neuroinflammation. They act as facultative immunocompetent antigen-presenting cells (APCs), expressing major histocompatibility complex (MHC) class II antigens upon activation with interferon (IFN)-γ and possibly other proinflammatory cytokines that are upregulated in disease states, including multiple sclerosis (MS). We characterized the anti-inflammatory effects of fingolimod (FTY720), an established drug for MS, and its phosphorylated metabolite (FTY720-P) in IFN-γ-activated cultured rat astrocytes. The expression of MHC class II compartments, β2 adrenergic receptor (ADR-β2), and nuclear factor kappa-light-chain enhancer of activated B cells subunit p65 (NF-κB p65) was quantified in immunofluorescence images acquired by laser scanning confocal microscopy. In addition, MHC class II-enriched endocytotic vesicles were labeled by fluorescent dextran and their mobility analyzed in astrocytes subjected to different treatments. FTY720 and FTY720-P treatment significantly reduced the number of IFN-γ-induced MHC class II compartments and substantially increased ADR-β2 expression, which is otherwise small or absent in astrocytes in MS. These effects could be partially attributed to the observed decrease in NF-κB p65 expression, because the NF-κB signaling cascade is activated in inflammatory processes. We also found attenuated trafficking and secretion from dextran-labeled endo-/lysosomes that may hinder efficient delivery of MHC class II molecules to the plasma membrane. Our data suggest that FTY720 and FTY720-P at submicromolar concentrations mediate anti-inflammatory effects on astrocytes by suppressing their action as APCs, which may further downregulate the inflammatory process in the brain, constituting the therapeutic effect of fingolimod in MS.
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37
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Rehni AK, Dave KR. Impact of Hypoglycemia on Brain Metabolism During Diabetes. Mol Neurobiol 2018; 55:9075-9088. [PMID: 29637442 PMCID: PMC6179939 DOI: 10.1007/s12035-018-1044-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/27/2018] [Indexed: 12/24/2022]
Abstract
Diabetes is a metabolic disease afflicting millions of people worldwide. A substantial fraction of world's total healthcare expenditure is spent on treating diabetes. Hypoglycemia is a serious consequence of anti-diabetic drug therapy, because it induces metabolic alterations in the brain. Metabolic alterations are one of the central mechanisms mediating hypoglycemia-related functional changes in the brain. Acute, chronic, and/or recurrent hypoglycemia modulate multiple metabolic pathways, and exposure to hypoglycemia increases consumption of alternate respiratory substrates such as ketone bodies, glycogen, and monocarboxylates in the brain. The aim of this review is to discuss hypoglycemia-induced metabolic alterations in the brain in glucose counterregulation, uptake, utilization and metabolism, cellular respiration, amino acid and lipid metabolism, and the significance of other sources of energy. The present review summarizes information on hypoglycemia-induced metabolic changes in the brain of diabetic and non-diabetic subjects and the manner in which they may affect brain function.
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Affiliation(s)
- Ashish K Rehni
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
- Department of Neurology, University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA
| | - Kunjan R Dave
- Cerebral Vascular Disease Research Laboratories, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
- Department of Neurology, University of Miami Miller School of Medicine, 1420 NW 9th Ave, NRB/203E, Miami, FL, 33136, USA.
- Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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Hisab AS. Effects of cyclic AMP on the differentiation and bioenergetics of rat C6 glioma cells. Int J Neurosci 2018; 129:230-244. [PMID: 30232914 DOI: 10.1080/00207454.2018.1526798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
INTRODUCTION Elevation in the level of intracellular cAMP is known to induce astrocytic differentiation of C6 glioma cells by unknown mechanisms. METHODS Therefore, cytoskeletal protein genes (phalloidin) fluorescents to investigate morphological changes, cell proliferation assay, MTT assay, flow cytometry, western blotting, in-cell western, immune-cytochemical (protein expression and localization), and oxygen electrodes (oxygen consumption rate) after a treatment with 0.25 mM dbcAMP were conducted. RESULTS Undifferentiated cells (media without dbcAMP) showed a flat polygonal appearance, whereas those cultured in the presence of 0.25 mM dbcAMP exhibited a more differentiated astrocytic morphology. They had more numerous neurite-like thin processes. The cell proliferation of differentiated c6 glioma reduced at day 2 and then started to increase at day 3 till day 5 compared to undifferentiated c6 glioma cells. In terms of flow-cytometry data, dbcAMP had no apoptotic effect on the C6 glioma cells. There was an increase in the protein expression GFAP (specific marker for astrocytes). There was no significant effect between undifferentiated and 5-day differentiation regarding their response to glucose 10 mM. In addition, there were no significant effects of glucose on the basal of 5-day differentiation of C6 glioma cells. However, there was a significant correlation between the concentration of glucose and inhibition of the basal oxygen consumption. Finally, glucose 10 mM did not stimulate NAD (P)H levels of C6 glioma cells. CONCLUSION The above results showed that cAMP induce C6 glioma cells differentiation without affecting its bioenergetics. Therefore cAMP is considered to be the best differentiating agent.
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Affiliation(s)
- Ahmed S Hisab
- a School of life Sciences , Queens Medical Centre , Nottingham , UK.,b Department of internal medicine, Faculty of veterinary medicine , Basrah University , Basra , Iraq
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Looser ZJ, Barrett MJP, Hirrlinger J, Weber B, Saab AS. Intravitreal AAV-Delivery of Genetically Encoded Sensors Enabling Simultaneous Two-Photon Imaging and Electrophysiology of Optic Nerve Axons. Front Cell Neurosci 2018; 12:377. [PMID: 30405358 PMCID: PMC6205974 DOI: 10.3389/fncel.2018.00377] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/03/2018] [Indexed: 11/21/2022] Open
Abstract
Myelination of axons by oligodendrocytes is a key feature of the remarkably fast operating CNS. Oligodendrocytes not only tune axonal conduction speed but are also suggested to maintain long-term axonal integrity by providing metabolic support to the axons they ensheath. However, how myelinating oligodendrocytes impact axonal energy homeostasis remains poorly understood and difficult to investigate. Here, we provide a method of how to study electrically active myelinated axons expressing genetically encoded sensors by combining electrophysiology and two-photon imaging of acutely isolated optic nerves. We show that intravitreal adeno-associated viral (AAV) vector delivery is an efficient tool to achieve functional sensor expression in optic nerve axons, which is demonstrated by measuring axonal ATP dynamics following AAV-mediated sensor expression. This novel approach allows for fast expression of any optical sensor of interest to be studied in optic nerve axons without the need to go through the laborious process of producing new transgenic mouse lines. Viral-mediated biosensor expression in myelinated axons and the subsequent combination of nerve recordings and sensor imaging outlines a powerful method to investigate oligodendroglial support functions and to further interrogate cellular mechanisms governing axonal energy homeostasis under physiological and pathological conditions.
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Affiliation(s)
- Zoe J. Looser
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Matthew J. P. Barrett
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Bruno Weber
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Aiman S. Saab
- Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
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Lactate transport facilitates neurite outgrowth. Biosci Rep 2018; 38:BSR20180157. [PMID: 30143583 PMCID: PMC6167502 DOI: 10.1042/bsr20180157] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 08/13/2018] [Accepted: 08/23/2018] [Indexed: 02/04/2023] Open
Abstract
How glia affect neurite outgrowth during neural development has not been well elucidated. In the present study, we found that disruption of lactate production using 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) and isofagomine significantly interfered with neurite outgrowth and that exogenous application of L-lactate rescued neurite growth failure. Monocarboxylate transporter-2-knockout, which blocked the lactate shuttle in neurons, showed a remarkable decrease in the length of axons and dendrites. We further demonstrated that Akt activity was decreased while glycogen synthase kinase 3β (GSK3β) activity was increased after astrocytic glycogen phosphorylase blockade. Additionally, GSK3βSer9 mutation reversed neurite growth failure caused by DAB and isofagomine. Our results suggested that lactate transportation played a critical role in neural development and disruption of the lactate shuttle in quiescent condition also affected neurite outgrowth in the central nervous system.
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Coggan JS, Keller D, Calì C, Lehväslaiho H, Markram H, Schürmann F, Magistretti PJ. Norepinephrine stimulates glycogenolysis in astrocytes to fuel neurons with lactate. PLoS Comput Biol 2018; 14:e1006392. [PMID: 30161133 PMCID: PMC6160207 DOI: 10.1371/journal.pcbi.1006392] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/27/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022] Open
Abstract
The mechanism of rapid energy supply to the brain, especially to accommodate the heightened metabolic activity of excited states, is not well-understood. We explored the role of glycogen as a fuel source for neuromodulation using the noradrenergic stimulation of glia in a computational model of the neural-glial-vasculature ensemble (NGV). The detection of norepinephrine (NE) by the astrocyte and the coupled cAMP signal are rapid and largely insensitive to the distance of the locus coeruleus projection release sites from the glia, implying a diminished impact for volume transmission in high affinity receptor transduction systems. Glucosyl-conjugated units liberated from glial glycogen by NE-elicited cAMP second messenger transduction winds sequentially through the glycolytic cascade, generating robust increases in NADH and ATP before pyruvate is finally transformed into lactate. This astrocytic lactate is rapidly exported by monocarboxylate transporters to the associated neuron, demonstrating that the astrocyte-to-neuron lactate shuttle activated by glycogenolysis is a likely fuel source for neuromodulation and enhanced neural activity. Altogether, the energy supply for both astrocytes and neurons can be supplied rapidly by glycogenolysis upon neuromodulatory stimulus. Although efficient compared to computers, the human brain utilizes energy at 10-fold the rate of other organs by mass. How the brain is supplied with sufficient on-demand energy to support its activity in the absence of neuronal storage capacity remains unknown. Neurons are not capable of meeting their own energy requirements, instead energy supply in the brain is managed by an oligocellular cartel composed of neurons, glia and the local vasculature (NGV), wherein glia can provide the ergogenic metabolite lactate to the neuron in a process called the astrocyte-to-neuron shuttle (ANLS). The only means of energy storage in the brain is glycogen, a polymerized form of glucose that is localized largely to astrocytes, but its exact role and conditions of use are not clear. In this computational model we show that neuromodulatory stimulation by norepinephrine induces astrocytes to recover glucosyl subunits from glycogen for use in a glycolytic process that favors the production of lactate. The ATP and NADH produced support metabolism in the astrocyte while the lactate is exported to feed the neuron. Thus, rapid energy demands by both neurons and glia in a stimulated brain can be met by glycogen mobilization.
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Affiliation(s)
- Jay S. Coggan
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- * E-mail: (JSC); (PJM)
| | - Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Corrado Calì
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Heikki Lehväslaiho
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Felix Schürmann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Pierre J. Magistretti
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
- * E-mail: (JSC); (PJM)
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Bilkei-Gorzo A, Albayram O, Ativie F, Chasan S, Zimmer T, Bach K, Zimmer A. Cannabinoid 1 receptor signaling on GABAergic neurons influences astrocytes in the ageing brain. PLoS One 2018; 13:e0202566. [PMID: 30114280 PMCID: PMC6095551 DOI: 10.1371/journal.pone.0202566] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/06/2018] [Indexed: 01/27/2023] Open
Abstract
Astrocytes, key regulators of brain homeostasis, interact with neighboring glial cells, neurons and the vasculature through complex processes involving different signaling pathways. It is not entirely clear how these interactions change in the ageing brain and which factors influence astrocyte ageing. Here, we investigate the role of endocannabinoid signaling, because it is an important modulator of neuron and astrocyte functions, as well as brain ageing. We demonstrate that mice with a specific deletion of CB1 receptors on GABAergic neurons (GABA-Cnr1-/- mice), which show a phenotype of accelerated brain ageing, affects age-related changes in the morphology of astrocytes in the hippocampus. Thus, GABA-Cnr1-/- mice showed a much more pronounced age-related and layer-specific increase in GFAP-positive areas in the hippocampus compared to wild-type animals. The number of astrocytes, in contrast, was similar between the two genotypes. Astrocytes in the hippocampus of old GABA-Cnr1-/- mice also showed a different morphology with enhanced GFAP-positive process branching and a less polarized intrahippocampal distribution. Furthermore, astrocytic TNFα levels were higher in GABA-Cnr1-/- mice, indicating that these morphological changes were accompanied by a more pro-inflammatory function. These findings demonstrate that the disruption of endocannabinoid signaling on GABAergic neurons is accompanied by functional changes in astrocyte activity, which are relevant to brain ageing.
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Affiliation(s)
- Andras Bilkei-Gorzo
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
- * E-mail:
| | - Onder Albayram
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
| | - Frank Ativie
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
| | - Safak Chasan
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
| | - Till Zimmer
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
| | - Karsten Bach
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, Medical Faculty of the University of Bonn, Bonn, Germany
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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44
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Gonzalez-Riano C, Sanz-Rodríguez M, Escudero-Ramirez J, Lorenzo MP, Barbas C, Cubelos B, Garcia A. Target and untargeted GC–MS based metabolomic study of mouse optic nerve and its potential in the study of neurological visual diseases. J Pharm Biomed Anal 2018; 153:44-56. [DOI: 10.1016/j.jpba.2018.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/05/2018] [Accepted: 02/07/2018] [Indexed: 11/29/2022]
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45
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Datta S, Chakrabarti N. Age related rise in lactate and its correlation with lactate dehydrogenase (LDH) status in post-mitochondrial fractions isolated from different regions of brain in mice. Neurochem Int 2018; 118:23-33. [PMID: 29678731 DOI: 10.1016/j.neuint.2018.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/11/2018] [Accepted: 04/11/2018] [Indexed: 02/06/2023]
Abstract
Rise in brain lactate is the hallmark of ageing. Separate studies report that ageing is associated with elevation of lactate level and alterations of lactate dehydrogenase (LDH)-A/B mRNA-expression-ratio in cerebral cortex and hippocampus. However, age related lactate rise in brain and its association with LDH status and their brain regional variations are still elusive. In the present study, level of lactate, LDH (A and B) activity and LDH-A expression were evaluated in post-mitochondrial fraction of tissues isolated from four different brain regions (cerebral cortex, hippocampus, substantia nigra and cerebellum) of young and aged mice. Lactate levels elevated in four brain regions with maximum rise in substantia nigra of aged mice. LDH-A protein expression and its activity decreased in cerebral cortex, hippocampus and substantia nigra without any changes of these parameters in cerebellum of aged mice. LDH-B activity decreased in hippocampus, substantia nigra and cerebellum whereas its activity remains unaltered in cerebral cortex of aged mice. Accordingly, the ratio of LDH-A/LDH-B-activity remains unaltered in hippocampus and substantia nigra, decreased in cerebral cortex and increased in cerebellum. Therefore, rise of lactate in three brain regions (cerebral cortex, hippocampus, substantia nigra) appeared to be not correlated with the alterations of its regulatory enzymes activities in these three brain regions, rather it supports the fact of involvement of other mechanisms, like lactate transport and/or aerobic/anaerobic metabolism as the possible cause(s) of lactate rise in these three brain regions. The increase in LDH-A/LDH-B-activity-ratio appeared to be positively correlated with elevated lactate level in cerebellum of aged mice. Overall, the present study indicates that the mechanism of rise in lactate in brain varies with brain regions where LDH status plays an important role during ageing.
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Affiliation(s)
- Siddhartha Datta
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India.
| | - Nilkanta Chakrabarti
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India; S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, West Bengal, India.
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46
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Rich LR, Brown AM. Fibre sub-type specific conduction reveals metabolic function in mouse sciatic nerve. J Physiol 2018. [PMID: 29517809 DOI: 10.1113/jp275680] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We have developed an improved method that enables simultaneous recording of stimulus evoked compound action potentials from large myelinated A fibres and small unmyelinated C fibres in mouse sciatic nerves. Investigations into the ability of fructose to support conduction in sciatic nerve revealed a novel glia-to-axon metabolic pathway in which fructose is converted in Schwann cells to lactate for subsequent shuttling to A fibres. The C fibres most likely directly take up and metabolise fructose. These differences are indicative of fibre sub-type specific metabolic profiles. These results demonstrate that the physiological insights provided by the method can be applied to investigations of peripheral nerve, with a view to understanding the metabolic disruptions that underlie diabetic neuropathy. ABSTRACT The stimulus evoked compound action potential (CAP), recorded using suction electrodes, provides an index of the relative number of conducting axons within a nerve trunk. As such the CAP has been used to elucidate the diverse mechanisms of injury resulting from a variety of metabolic insults to central nervous white matter, whilst also providing a model with which to assess the benefits of clinically relevant neuroprotective strategies. In addition the technique lends itself to the study of metabolic cell-to-cell signalling that occurs between glial cells and neurones, and to exploring the ability of non-glucose substrates to support axon conduction. Although peripheral nerves are sensitive to metabolic insult and are susceptible to diabetic neuropathy, there is a lack of fundamental information regarding peripheral nerve metabolism. A confounding factor in such studies is the extended duration demanded by the experimental protocol, requiring stable recording for periods of many hours. We describe a method that allows us to record simultaneously the stimulus evoked CAPs from A and C fibres from mouse sciatic nerve, and demonstrate its utility as applied to investigations into fibre sub-type substrate use. Our results suggest that C fibres directly take up and metabolise fructose, whereas A fibre conduction is supported by fructose-derived lactate, implying there exist unique metabolic profiles in neighbouring fibre sub-types present within the same nerve trunk.
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Affiliation(s)
- Laura R Rich
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Angus M Brown
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK.,Department of Neurology, School of Medicine, University of Washington, Seattle, WA, 98195, USA
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Korol DL, Wang W. Using a memory systems lens to view the effects of estrogens on cognition: Implications for human health. Physiol Behav 2018; 187:67-78. [PMID: 29203121 PMCID: PMC5844822 DOI: 10.1016/j.physbeh.2017.11.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 01/23/2023]
Abstract
Understanding the organizing and activating effects of gonadal steroids on adult physiology can guide insight into sex differences in and hormonal influences on health and disease, ranging from diabetes and other metabolic disorders, emotion and stress regulation, substance abuse, pain perception, immune function and inflammation, to cognitive function and dysfunction accompanying neurological disorders. Because the brain is highly sensitive to many forms of estrogens, it is not surprising that many adult behaviors, including cognitive function, are modulated by estrogens. Estrogens are known for their facilitating effects on learning and memory, but it is becoming increasingly clear that they also can impair learning and memory of some classes of tasks and may do so through direct actions on specific neural systems. This review takes a multiple memory systems approach to understanding how estrogens can at the same time enhance hippocampus-sensitive place learning and impair striatum-sensitive response learning by exploring the role estrogen receptor signaling may play in the opposing cognitive effects of estrogens. Accumulating evidence suggests that neither receptor subtype nor the timing of treatment, i.e. rapid vs slow, explain the bidirectional effects of estrogens on different types of learning. New findings pointing to neural metabolism and the provision of energy substrates by astrocytes as a candidate mechanism for cognitive enhancement and impairment are discussed.
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Affiliation(s)
- Donna L Korol
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States.
| | - Wei Wang
- Department of Biology, Syracuse University, Syracuse, NY 13244, United States
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Bak LK, Walls AB, Schousboe A, Waagepetersen HS. Astrocytic glycogen metabolism in the healthy and diseased brain. J Biol Chem 2018; 293:7108-7116. [PMID: 29572349 DOI: 10.1074/jbc.r117.803239] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The brain contains a fairly low amount of glycogen, mostly located in astrocytes, a fact that has prompted the suggestion that glycogen does not have a significant physiological role in the brain. However, glycogen metabolism in astrocytes is essential for several key physiological processes and is adversely affected in disease. For instance, diminished ability to break down glycogen impinges on learning, and epilepsy, Alzheimer's disease, and type 2 diabetes are all associated with abnormal astrocyte glycogen metabolism. Glycogen metabolism supports astrocytic K+ and neurotransmitter glutamate uptake and subsequent glutamine synthesis-three fundamental steps in excitatory signaling at most brain synapses. Thus, there is abundant evidence for a key role of glycogen in brain function. Here, we summarize the physiological brain functions that depend on glycogen, discuss glycogen metabolism in disease, and investigate how glycogen breakdown is regulated at the cellular and molecular levels.
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Affiliation(s)
- Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Anne B Walls
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
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Correale J, Ysrraelit MC, Benarroch EE. Metabolic coupling of axons and glial cells. Neurology 2018; 90:737-744. [DOI: 10.1212/wnl.0000000000005339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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50
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Freeman RD, Li B. Neural-metabolic coupling in the central visual pathway. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0357. [PMID: 27574310 DOI: 10.1098/rstb.2015.0357] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 01/19/2023] Open
Abstract
Studies are described which are intended to improve our understanding of the primary measurements made in non-invasive neural imaging. The blood oxygenation level-dependent signal used in functional magnetic resonance imaging (fMRI) reflects changes in deoxygenated haemoglobin. Tissue oxygen concentration, along with blood flow, changes during neural activation. Therefore, measurements of tissue oxygen together with the use of a neural sensor can provide direct estimates of neural-metabolic interactions. We have used this relationship in a series of studies in which a neural microelectrode is combined with an oxygen micro-sensor to make simultaneous co-localized measurements in the central visual pathway. Oxygen responses are typically biphasic with small initial dips followed by large secondary peaks during neural activation. By the use of established visual response characteristics, we have determined that the oxygen initial dip provides a better estimate of local neural function than the positive peak. This contrasts sharply with fMRI for which the initial dip is unreliable. To extend these studies, we have examined the relationship between the primary metabolic agents, glucose and lactate, and associated neural activity. For this work, we also use a Doppler technique to measure cerebral blood flow (CBF) together with neural activity. Results show consistent synchronously timed changes such that increases in neural activity are accompanied by decreases in glucose and simultaneous increases in lactate. Measurements of CBF show clear delays with respect to neural response. This is consistent with a slight delay in blood flow with respect to oxygen delivery during neural activation.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- Ralph D Freeman
- Group in Vision Science, School of Optometry, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720-2020, USA
| | - Baowang Li
- Group in Vision Science, School of Optometry, Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720-2020, USA
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