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Braga A, Chiacchiaretta M, Pellerin L, Kong D, Haydon PG. Astrocytic metabolic control of orexinergic activity in the lateral hypothalamus regulates sleep and wake architecture. Nat Commun 2024; 15:5979. [PMID: 39013907 PMCID: PMC11252394 DOI: 10.1038/s41467-024-50166-7] [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: 10/27/2023] [Accepted: 06/17/2024] [Indexed: 07/18/2024] Open
Abstract
Neuronal activity undergoes significant changes during vigilance states, accompanied by an accommodation of energy demands. While the astrocyte-neuron lactate shuttle has shown that lactate is the primary energy substrate for sustaining neuronal activity in multiple brain regions, its role in regulating sleep/wake architecture is not fully understood. Here we investigated the involvement of astrocytic lactate supply in maintaining consolidated wakefulness by downregulating, in a cell-specific manner, the expression of monocarboxylate transporters (MCTs) in the lateral hypothalamus of transgenic mice. Our results demonstrate that reduced expression of MCT4 in astrocytes disrupts lactate supply to wake-promoting orexin neurons, impairing wakefulness stability. Additionally, we show that MCT2-mediated lactate uptake is necessary for maintaining tonic firing of orexin neurons and stabilizing wakefulness. Our findings provide both in vivo and in vitro evidence supporting the role of astrocyte-to-orexinergic neuron lactate shuttle in regulating proper sleep/wake stability.
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Affiliation(s)
- Alice Braga
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Martina Chiacchiaretta
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA.
| | - Luc Pellerin
- Inserm U1313, University and CHU of Poitiers, 86021, Poitiers, France
| | - Dong Kong
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA
- Division of Endocrinology, Department of Pediatrics, F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA.
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2
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Tassinari ID, Rodrigues FDS, Bertram C, Mendes-da-Cruz DA, Guedes RP, Paz AH, Bambini-Junior V, de Fraga LS. Lactate Protects Microglia and Neurons from Oxygen-Glucose Deprivation/Reoxygenation. Neurochem Res 2024; 49:1762-1781. [PMID: 38551797 DOI: 10.1007/s11064-024-04135-7] [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: 12/29/2023] [Revised: 02/06/2024] [Accepted: 02/20/2024] [Indexed: 06/02/2024]
Abstract
Lactate has received attention as a potential therapeutic intervention for brain diseases, particularly those including energy deficit, exacerbated inflammation, and disrupted redox status, such as cerebral ischemia. However, lactate roles in metabolic or signaling pathways in neural cells remain elusive in the hypoxic and ischemic contexts. Here, we tested the effects of lactate on the survival of a microglial (BV-2) and a neuronal (SH-SY5Y) cell lines during oxygen and glucose deprivation (OGD) or OGD followed by reoxygenation (OGD/R). Lactate signaling was studied by using 3,5-DHBA, an exogenous agonist of lactate receptor GPR81. Inhibition of lactate dehydrogenase (LDH) or monocarboxylate transporters (MCT), using oxamate or 4-CIN, respectively, was performed to evaluate the impact of lactate metabolization and transport on cell viability. The OGD lasted 6 h and the reoxygenation lasted 24 h following OGD (OGD/R). Cell viability, extracellular lactate concentrations, microglial intracellular pH and TNF-ɑ release, and neurite elongation were evaluated. Lactate or 3,5-DHBA treatment during OGD increased microglial survival during reoxygenation. Inhibition of lactate metabolism and transport impaired microglial and neuronal viability. OGD led to intracellular acidification in BV-2 cells, and reoxygenation increased the release of TNF-ɑ, which was reverted by lactate and 3,5-DHBA treatment. Our results suggest that lactate plays a dual role in OGD, acting as a metabolic and a signaling molecule in BV-2 and SH-SY5Y cells. Lactate metabolism and transport are vital for cell survival during OGD. Moreover, lactate treatment and GPR81 activation during OGD promote long-term adaptations that potentially protect cells against secondary cell death during reoxygenation.
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Affiliation(s)
- Isadora D'Ávila Tassinari
- Graduate Program in Physiology, Institute of Basic Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, 90050-003, Brazil
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YW, UK
| | - Fernanda da Silva Rodrigues
- Graduate Program in Biosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, 90050-170, Brazil
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YW, UK
| | - Craig Bertram
- School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Daniella Arêas Mendes-da-Cruz
- Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, 21040-360, Brazil
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YW, UK
| | - Renata Padilha Guedes
- Graduate Program in Biosciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, 90050-170, Brazil
| | - Ana Helena Paz
- Graduate Program in Physiology, Institute of Basic Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, 90050-003, Brazil
| | - Victorio Bambini-Junior
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YW, UK
| | - Luciano Stürmer de Fraga
- Graduate Program in Physiology, Institute of Basic Health Sciences (ICBS), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, 90050-003, Brazil.
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3
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Hamadani CM, Mahdi F, Merrell A, Flanders J, Cao R, Vashisth P, Dasanayake GS, Darlington DS, Singh G, Pride MC, Monroe WG, Taylor GR, Hunter AN, Roman G, Paris JJ, Tanner EEL. Ionic Liquid Coating-Driven Nanoparticle Delivery to the Brain: Applications for NeuroHIV. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305484. [PMID: 38572510 PMCID: PMC11186118 DOI: 10.1002/advs.202305484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/28/2023] [Indexed: 04/05/2024]
Abstract
Delivering cargo to the central nervous system (CNS) remains a pharmacological challenge. For infectious diseases such as HIV, the CNS acts as a latent reservoir that is inadequately managed by systemic antiretrovirals (ARTs). ARTs thus cannot eradicate HIV, and given CNS infection, patients experience neurological deficits collectively referred to as "neuroHIV". Herein, the development of bioinspired ionic liquid-coated nanoparticles (IL-NPs) for in situ hitchhiking on red blood cells (RBCs) is reported, which enables 48% brain delivery of intracarotid arterial- infused cargo. Moreover, IL choline trans-2-hexenoate (CA2HA 1:2) demonstrates preferential accumulation in parenchymal microglia over endothelial cells post-delivery. This study further demonstrates successful loading of abacavir (ABC), an ART that is challenging to encapsulate, into IL-NPs, and verifies retention of antiviral efficacy in vitro. IL-NPs are not cytotoxic to primary human peripheral blood mononuclear cells (PBMCs) and the CA2HA 1:2 coating itself confers notable anti-viremic capacity. In addition, in vitro cell culture assays show markedly increased uptake of IL-NPs into neural cells compared to bare PLGA nanoparticles. This work debuts bioinspired ionic liquids as promising nanoparticle coatings to assist CNS biodistribution and has the potential to revolutionize the delivery of cargos (i.e., drugs, viral vectors) through compartmental barriers such as the blood-brain-barrier (BBB).
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Affiliation(s)
- Christine M. Hamadani
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Fakhri Mahdi
- Department of BioMolecular SciencesThe University of MississippiUniversityMS38677USA
| | - Anya Merrell
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Jack Flanders
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Ruofan Cao
- Department of BioMolecular SciencesThe University of MississippiUniversityMS38677USA
| | - Priyavrat Vashisth
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Gaya S. Dasanayake
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Donovan S. Darlington
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Gagandeep Singh
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Mercedes C. Pride
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Wake G. Monroe
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - George R. Taylor
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Alysha N. Hunter
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
| | - Gregg Roman
- Department of BioMolecular SciencesThe University of MississippiUniversityMS38677USA
| | - Jason J. Paris
- Department of BioMolecular SciencesThe University of MississippiUniversityMS38677USA
| | - Eden E. L. Tanner
- Department of Chemistry & BiochemistryThe University of MississippiUniversityMS38677USA
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4
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Xu Y, Kusuyama J, Osana S, Matsuhashi S, Li L, Takada H, Inada H, Nagatomi R. Lactate promotes neuronal differentiation of SH-SY5Y cells by lactate-responsive gene sets through NDRG3-dependent and -independent manners. J Biol Chem 2023:104802. [PMID: 37172727 DOI: 10.1016/j.jbc.2023.104802] [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: 10/22/2022] [Revised: 04/23/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023] Open
Abstract
Lactate serves as the major glucose alternative to an energy substrate in the brain. Lactate level is increased in the fetal brain from the middle stage of gestation, indicating the involvement of lactate in brain development and neuronal differentiation. Recent reports show that lactate functions as a signaling molecule to regulate gene expression and protein stability. However, the roles of lactate signaling in neuronal cells remain unknown. Here, we showed that lactate promotes the all stages of neuronal differentiation of SH-SY5Y and Neuro2A, human and mouse neuroblastoma cell lines, characterized by increased neuronal marker expression and the rates of neurites extension. Transcriptomics revealed many lactate-responsive genes sets such as SPARCL1 in SH-SY5Y, Neuro2A, and primary embryonic mouse neuronal cells. The effects of lactate on neuronal function were mainly mediated through monocarboxylate transporters 1 (MCT1). We found that NDRG family member 3 (NDRG3), a lactate-binding protein, was highly expressed and stabilized by lactate treatment during neuronal differentiation. Combinative RNA-seq of SH-SY5Y with lactate treatment and NDRG3 knockdown shows that the promotive effects of lactate on neural differentiation are regulated through NDRG3-dependent and independent manners. Moreover, we identified TEA domain family member 1 (TEAD1) and ETS-related transcription factor 4 (ELF4) are the specific transcription factors that are regulated by both lactate and NDRG3 in neuronal differentiation. TEAD1 and ELF4 differently affect the expression of neuronal marker genes in SH-SY5Y cells. These results highlight the biological roles of extracellular and intracellular lactate as a critical signaling molecule that modifies neuronal differentiation.
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Affiliation(s)
- Yidan Xu
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Joji Kusuyama
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Department of Biosignals and Inheritance, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
| | - Shion Osana
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Graduate School of Informatics and Engineering, University of Electro-Communications
| | - Satayuki Matsuhashi
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
| | - Longfei Li
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Hiroaki Takada
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan
| | - Hitoshi Inada
- Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Department of Developmental Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryoichi Nagatomi
- Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan; Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.
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5
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Pérez-Sala D, Pajares MA. Appraising the Role of Astrocytes as Suppliers of Neuronal Glutathione Precursors. Int J Mol Sci 2023; 24:ijms24098059. [PMID: 37175763 PMCID: PMC10179008 DOI: 10.3390/ijms24098059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/25/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
The metabolism and intercellular transfer of glutathione or its precursors may play an important role in cellular defense against oxidative stress, a common hallmark of neurodegeneration. In the 1990s, several studies in the Neurobiology field led to the widely accepted notion that astrocytes produce large amounts of glutathione that serve to feed neurons with precursors for glutathione synthesis. This assumption has important implications for health and disease since a reduction in this supply from astrocytes could compromise the capacity of neurons to cope with oxidative stress. However, at first glance, this shuttling would imply a large energy expenditure to get to the same point in a nearby cell. Thus, are there additional underlying reasons for this expensive mechanism? Are neurons unable to import and/or synthesize the three non-essential amino acids that are the glutathione building blocks? The rather oxidizing extracellular environment favors the presence of cysteine (Cys) as cystine (Cis), less favorable for neuronal import. Therefore, it has also been proposed that astrocytic GSH efflux could induce a change in the redox status of the extracellular space nearby the neurons, locally lowering the Cis/Cys ratio. This astrocytic glutathione release would also increase their demand for precursors, stimulating Cis uptake, which these cells can import, further impacting the local decline of the Cis/Cys ratio, in turn, contributing to a more reduced extracellular environment and subsequently favoring neuronal Cys import. Here, we revisit the experimental evidence that led to the accepted hypothesis of astrocytes acting as suppliers of neuronal glutathione precursors, considering recent data from the Human Protein Atlas. In addition, we highlight some potential drawbacks of this hypothesis, mainly supported by heterogeneous cellular models. Finally, we outline additional and more cost-efficient possibilities by which astrocytes could support neuronal glutathione levels, including its shuttling in extracellular vesicles.
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Affiliation(s)
- Dolores Pérez-Sala
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María A Pajares
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
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6
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Hasel P, Aisenberg WH, Bennett FC, Liddelow SA. Molecular and metabolic heterogeneity of astrocytes and microglia. Cell Metab 2023; 35:555-570. [PMID: 36958329 DOI: 10.1016/j.cmet.2023.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/26/2023] [Accepted: 03/08/2023] [Indexed: 03/25/2023]
Abstract
Astrocytes and microglia are central players in a myriad of processes in the healthy and diseased brain, ranging from metabolism to immunity. The crosstalk between these two cell types contributes to pathology in many if not all neuroinflammatory and neurodegenerative diseases. Recent advancements in integrative multimodal sequencing techniques have begun to highlight how heterogeneous both cell types are and the importance of metabolism to their regulation. We discuss here the transcriptomic, metabolic, and functional heterogeneity of astrocytes and microglia and highlight their interaction in health and disease.
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Affiliation(s)
- Philip Hasel
- Neuroscience Institute, NYU Grossman School of Medicine, New York, NY 10016, USA.
| | - William H Aisenberg
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - F Chris Bennett
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | - Shane A Liddelow
- Neuroscience Institute, NYU Grossman School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, NYU Grossman School of Medicine, New York, NY 10016, USA; Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY 10016, USA; Parekh Center for Interdisciplinary Neurology, NYU Grossman School of Medicine, New York, NY 10016, USA.
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7
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Lactate and Lactylation in the Brain: Current Progress and Perspectives. Cell Mol Neurobiol 2023:10.1007/s10571-023-01335-7. [PMID: 36928470 DOI: 10.1007/s10571-023-01335-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/04/2023] [Indexed: 03/18/2023]
Abstract
As the final product of glycolysis, lactate features not only as an energy substrate, a metabolite, and a signaling molecule in a variety of diseases-such as cancer, inflammation, and sepsis-but also as a regulator of protein lactylation; this is a newly proposed epigenetic modification that is considered to be crucial for energy metabolism and signaling in brain tissues under both physiological and pathological conditions. In this review, evidence on lactylation from studies on lactate metabolism and disease has been summarized, revealing the function of lactate and its receptors in the regulation of brain function and summarizing the levels of lactylation expression in various brain diseases. Finally, the function of lactate and lactylation in the brain and the potential mechanisms of intervention in brain diseases are presented and discussed, providing optimal perspectives for future research on the role of lactylation in the brain.
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8
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Hamadani CM, Mahdi F, Merrell A, Flanders J, Cao R, Vashisth P, Pride MC, Hunter AN, Singh G, Roman G, Paris JJ, Tanner EEL. Ionic Liquid Coating-Driven Nanoparticle Delivery to the Brain: Applications for NeuroHIV. RESEARCH SQUARE 2023:rs.3.rs-2574352. [PMID: 36824802 PMCID: PMC9949257 DOI: 10.21203/rs.3.rs-2574352/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Delivering cargo to the central nervous system (CNS) remains a pharmacological challenge. For infectious diseases such as HIV, the CNS acts as a latent reservoir that is inadequately managed by systemic antiretrovirals (ARTs). ARTs thus cannot eradicate HIV, and given CNS infection, patients experience an array of neurological deficits that are collectively referred to as 'neuroHIV'. Herein we report the development of bioinspired ionic liquid-coated nanoparticles (IL-NPs) for in situ hitchhiking on red blood cells (RBCs), which enabled 48% delivery of intravenously infused cargo to the brain. Moreover, the ionic liquid (IL) choline trans-2-hexenoate (CA2HA 1:2) demonstrated preferential accumulation in parenchymal microglia over endothelial cells post-delivery. We further demonstrate the successful loading of abacavir (ABC), an ART that is challenging to encapsulate, into the IL-coated NPs and verify the retention of antiviral efficacy in vitro. IL-NPs were not cytotoxic to primary human peripheral blood mononuclear cells (PBMCs) and the CA2HA 1:2 coating conferred notable anti-viremic capacity on its own. In addition, in vitro cell culture assays showed markedly increased uptake of IL-coated nanoparticles into neuronal cells compared to bare nanoparticles. This work debuts bioinspired ionic liquids as promising nanoparticle coatings to assist CNS biodistribution and has the potential to revolutionize the delivery of cargos (i.e., drugs, viral vectors) through compartmental barriers such as the blood-brain-barrier (BBB), illustrated in the graphical abstract below.
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9
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Lushchak VI, Duszenko M, Gospodaryov DV, Garaschuk O. Oxidative Stress and Energy Metabolism in the Brain: Midlife as a Turning Point. Antioxidants (Basel) 2021; 10:1715. [PMID: 34829586 PMCID: PMC8614699 DOI: 10.3390/antiox10111715] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/23/2021] [Accepted: 10/25/2021] [Indexed: 01/10/2023] Open
Abstract
Neural tissue is one of the main oxygen consumers in the mammalian body, and a plentitude of metabolic as well as signaling processes within the brain is accompanied by the generation of reactive oxygen (ROS) and nitrogen (RNS) species. Besides the important signaling roles, both ROS and RNS can damage/modify the self-derived cellular components thus promoting neuroinflammation and oxidative stress. While previously, the latter processes were thought to progress linearly with age, newer data point to midlife as a critical turning point. Here, we describe (i) the main pathways leading to ROS/RNS generation within the brain, (ii) the main defense systems for their neutralization and (iii) summarize the recent literature about considerable changes in the energy/ROS homeostasis as well as activation state of the brain's immune system at midlife. Finally, we discuss the role of calorie restriction as a readily available and cost-efficient antiaging and antioxidant lifestyle intervention.
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Affiliation(s)
- Volodymyr I. Lushchak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., 76018 Ivano-Frankivsk, Ukraine; (V.I.L.); (D.V.G.)
- Department of Medical Biochemistry, I. Horbachevsky Ternopil National Medical University, 46002 Ternopil, Ukraine
- Research and Development University, 13a Shota Rustaveli Str., 76018 Ivano-Frankivsk, Ukraine
| | - Michael Duszenko
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, 72074 Tübingen, Germany;
| | - Dmytro V. Gospodaryov
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., 76018 Ivano-Frankivsk, Ukraine; (V.I.L.); (D.V.G.)
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, 72074 Tübingen, Germany;
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10
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Jurga AM, Paleczna M, Kadluczka J, Kuter KZ. Beyond the GFAP-Astrocyte Protein Markers in the Brain. Biomolecules 2021; 11:biom11091361. [PMID: 34572572 PMCID: PMC8468264 DOI: 10.3390/biom11091361] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022] Open
Abstract
The idea of central nervous system as one-man band favoring neurons is long gone. Now we all are aware that neurons and neuroglia are team players and constant communication between those various cell types is essential to maintain functional efficiency and a quick response to danger. Here, we summarize and discuss known and new markers of astroglial multiple functions, their natural heterogeneity, cellular interactions, aging and disease-induced dysfunctions. This review is focused on newly reported facts regarding astrocytes, which are beyond the old stereotypes. We present an up-to-date list of marker proteins used to identify a broad spectrum of astroglial phenotypes related to the various physiological and pathological nervous system conditions. The aim of this review is to help choose markers that are well-tailored for specific needs of further experimental studies, precisely recognizing differential glial phenotypes, or for diagnostic purposes. We hope it will help to categorize the functional and structural diversity of the astroglial population and ease a clear readout of future experimental results.
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11
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Benyahia Z, Blackman MCNM, Hamelin L, Zampieri LX, Capeloa T, Bedin ML, Vazeille T, Schakman O, Sonveaux P. In Vitro and In Vivo Characterization of MCT1 Inhibitor AZD3965 Confirms Preclinical Safety Compatible with Breast Cancer Treatment. Cancers (Basel) 2021; 13:cancers13030569. [PMID: 33540599 PMCID: PMC7867268 DOI: 10.3390/cancers13030569] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 01/24/2021] [Accepted: 01/30/2021] [Indexed: 12/04/2022] Open
Abstract
Simple Summary The vast majority of tumors originate in tissues that use different substrates and oxygen to produce energy. However, tumors are disorganized structurally and functionally, which creates areas where oxygen and nutrients are poorly available. To survive and proliferate, cancer cells adapt by switching their metabolism to lactic fermentation. Their fate is further optimized by intercellular cooperation, but this creates a weakness that can be exploited therapeutically. Indeed, AZD3965 is a new drug currently tested in clinical trials that inhibits a cooperation based on lactate swapping for glucose between fermenting and respiring cells. It inhibits lactate transporter monocarboxylate transporter 1. Here, using malignant and nonmalignant cells representative of the breast tissue and several behavioral tests in mice, we establish that AZD3965 is safe for therapeutic use against cancer. The only side effect that we detected was a short-term memory retention defect that transiently perturbed the orientation of mice in space. Abstract To survive and proliferate in solid tumors, cancer cells adapt and evolve rapidly in microenvironments where oxygen and substrate bioavailability fluctuates over time and space. This creates metabolic heterogeneity. Cancer cells can further cooperate metabolically, for example by swapping glycolytic end-product lactate for blood-borne glucose. This type of cooperation can be targeted therapeutically, since transmembrane lactate exchanges are facilitated by lactate-proton symporters of the monocarboxylate (MCT) family. Among new drugs, AZD3965 is a first-in-class selective MCT1 inhibitor currently tested in Phase I/II clinical trials for patients with different types of cancers. Because MCT1 can function bidirectionally, we tested here whether and how malignant and nonmalignant cells adapt their metabolism and MCT repertoire when AZD3965 inhibits either lactate import or export. Using breast-associated malignant and nonmalignant cell lines as models, we report that AZD3965 is not directly cytotoxic. In the presence of glucose and glutamine, oxidative cells can survive when lactate uptake is blocked, and proliferating cells compensate MCT1 inhibition by overexpressing MCT4, a specialized facilitator of lactate export. Phenotypic characterization of mice focusing on metabolism, muscle and brain physiology found partial and transient memory retention defect as sole consequence of MCT1 inhibition by AZD3965. We therefore conclude that AZD3965 is compatible with anticancer therapy.
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Affiliation(s)
- Zohra Benyahia
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Marine C. N. M. Blackman
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Loïc Hamelin
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Luca X. Zampieri
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Tania Capeloa
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Marie L. Bedin
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Thibaut Vazeille
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
| | - Olivier Schakman
- Pole of Cell Physiology, Institut des Neurosciences (IoNS), Université Catholique de Louvain (UCLouvain), Avenue E. Mounier 53 box B1.53.17, 1200 Brussels, Belgium;
| | - Pierre Sonveaux
- Pole of Pharmacology and Therapeutics, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 57 box B1.57.04, 1200 Brussels, Belgium; (Z.B.); (M.C.N.M.B.); (L.H.); (L.X.Z.); (T.C.); (M.L.B.); (T.V.)
- Correspondence:
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12
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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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13
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Netzahualcoyotzi C, Pellerin L. Neuronal and astroglial monocarboxylate transporters play key but distinct roles in hippocampus-dependent learning and memory formation. Prog Neurobiol 2020; 194:101888. [PMID: 32693190 DOI: 10.1016/j.pneurobio.2020.101888] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/07/2020] [Accepted: 07/16/2020] [Indexed: 01/26/2023]
Abstract
Brain lactate formation, intercellular exchange and utilization has been implicated in memory formation. However, the individual role of either neuronal or astroglial monocarboxylate transporters for the acquisition and consolidation of information remains incomplete. Using novel transgenic mice and a viral vector approach to decrease the expression of each transporter in a cell-specific manner within the dorsal hippocampus, we show that both neuronal MCT2 and astroglial MCT4 are required for spatial information acquisition and retention (at 24 h post-training) in distinct hippocampus-dependent tasks. Intracerebral infusion of lactate rescued spatial learning in mice with reduced levels of astroglial MCT4 but not of neuronal MCT2, suggesting that lactate transfer from astrocytes and utilization in neurons contribute to hippocampal-dependent learning. In contrast, only neuronal MCT2 was shown to be required for long-term (7 days post training) memory formation. Interestingly, reduced MCT2 expression levels in mature neurons result in a heterologous effect as it blunts hippocampal neurogenesis associated with memory consolidation. These results suggest important but distinct contributions of both neuronal MCT2 and astroglial MCT4 in learning and memory processes, going beyond a simple passive role as alternative energy substrate suppliers or in waste product disposal.
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Affiliation(s)
| | - Luc Pellerin
- Department of Physiology, University of Lausanne, 7 Rue du Bugnon, 1005 Lausanne, Switzerland; Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/Université de Bordeaux, 146 rue Léo Saignat, Bordeaux 33076, France.
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14
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Ding R, Tan Y, Du A, Wen G, Ren X, Yao H, Ren W, Liu H, Wang X, Yu H, Yao J, Li B, Zhang G, Lu Y, Wu X. Redistribution of Monocarboxylate 1 and 4 in Hippocampus and Spatial Memory Impairment Induced by Long-term Ketamine Administration. Front Behav Neurosci 2020; 14:60. [PMID: 32362817 PMCID: PMC7181955 DOI: 10.3389/fnbeh.2020.00060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
The monocarboxylate transporters (MCTs) MCT1, MCT2, and MCT4 are essential components of the astrocyte-neuron lactate shuttle (ANLS), which is a fundamental element of brain energetics. Decreased expression of MCTs can induce cognitive dysfunction of the brain. In the present study, we established a mouse model of long-term ketamine administration by subjecting mice to a 6-month course of a daily intraperitoneal injection of ketamine. These mice demonstrated learning and memory deficits and a significant decline in MCT1 and MCT4 proteins in the hippocampal membrane fraction, while cytoplasmic MCT1 and MCT4 protein levels were significantly increased. In contrast, the levels of global MCT2 protein were significantly increased. Analysis of mRNA levels found no changes in MCT1/4 transcripts, although the expression of MCT2 mRNA was significantly increased. We suggest that redistribution of hippocampal MCT1 and MCT4, but not MCT2 up-regulation, may be related to learning and memory deficits induced by long-term ketamine administration.
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Affiliation(s)
- Runtao Ding
- School of Forensic Medicine, China Medical University, Shenyang, China.,Department of Forensic and Medical Laboratory, Jining Medical University, Jining, China
| | - Yaqing Tan
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Ao Du
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Gehua Wen
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Xinghua Ren
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Hui Yao
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Weishu Ren
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Huairu Liu
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Xiaolong Wang
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Hao Yu
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Jun Yao
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Baoman Li
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Guohua Zhang
- School of Forensic Medicine, China Medical University, Shenyang, China
| | - Yan Lu
- Key Laboratory of Health Ministry in Congenital Malformation, The Affiliated Shengjing Hospital of China Medical University, Shenyang, China
| | - Xu Wu
- School of Forensic Medicine, China Medical University, Shenyang, China
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15
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CAIX forms a transport metabolon with monocarboxylate transporters in human breast cancer cells. Oncogene 2019; 39:1710-1723. [PMID: 31723238 DOI: 10.1038/s41388-019-1098-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/28/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023]
Abstract
Tumor cells rely on glycolysis to meet their elevated demand for energy. Thereby they produce significant amounts of lactate and protons, which are exported via monocarboxylate transporters (MCTs), supporting the formation of an acidic microenvironment. The present study demonstrates that carbonic anhydrase IX (CAIX), one of the major acid/base regulators in cancer cells, forms a protein complex with MCT1 and MCT4 in tissue samples from human breast cancer patients, but not healthy breast tissue. Formation of this transport metabolon requires binding of CAIX to the Ig1 domain of the MCT1/4 chaperon CD147 and is required for CAIX-mediated facilitation of MCT1/4 activity. Application of an antibody, directed against the CD147-Ig1 domain, displaces CAIX from the transporter and suppresses CAIX-mediated facilitation of proton-coupled lactate transport. In cancer cells, this "metabolon disruption" results in a decrease in lactate transport, reduced glycolysis, and ultimately reduced cell proliferation. Taken together, the study shows that carbonic anhydrases form transport metabolons with acid/base transporters in human tumor tissue and that these interactions can be exploited to interfere with tumor metabolism and proliferation.
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16
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Pang R, Wang X, Du Z, Pei F, Li Z, Sun L, Wang S, Peng Y, Lu X, Gao X, Chang C. The distribution and density of monocarboxylate transporter 2 in cerebral cortex, hippocampus and cerebellum of wild-type mice. J Anat 2019; 236:370-377. [PMID: 31713246 DOI: 10.1111/joa.13099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 01/07/2023] Open
Abstract
Monocarboxylates cannot cross the blood-brain barrier freely to participate in brain energy metabolism. Specific monocarboxylate transporters (MCTs) are needed to cross cellular membranes. Monocarboxylate transporter 2 (MCT2) is a major monocarboxylate transporter encoded by the SLC16A7 gene. Recent studies reported that neurodegenerative diseases of the CNS, such as Alzheimer's disease (AD) and Parkinson's disease (PD), were related to energy metabolic impairment. MCT2 also plays an important role in energy metabolism in the CNS. To provide experimental evidence for future research on the role of MCT2 in the pathological process of CNS degenerative diseases, the distribution and density of MCT2 in different subregions of wild-type mouse brain was examined using immunohistochemistry, western blot and immunogold post-embedding electron microscopic techniques. The amount of MCT2 was higher in cerebellum than in cortex and hippocampus on western blots, and there was no statistical difference between cortex and hippocampus. Immunohistochemistry assay revealed the highest density of MCT2 in the CA3 of the hippocampus. The granular cell layer of the cerebellum contained more MCT2 than the molecular layer. The MCT2 density on the end feet of astrocytes of molecular layer was lower than in hippocampus, but the postsynaptic densities (PSDs) of asymmetric synapses in the molecular layer exhibited a high density using immunogold post-embedding electron microscopic techniques.
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Affiliation(s)
- Ruiqi Pang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaofan Wang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhiqiang Du
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Feifei Pei
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhiyue Li
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Libing Sun
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shuying Wang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yingnan Peng
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xupeng Lu
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaoqun Gao
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.,Center of Cerebral Palsy Surgical Research and Treatment, Zhengzhou University, Zhengzhou, China.,Birth Defect Prevention Key Laboratory, National Health Commission of the People's Republic of China, Zhengzhou, China
| | - Cheng Chang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.,Center of Cerebral Palsy Surgical Research and Treatment, Zhengzhou University, Zhengzhou, China.,Birth Defect Prevention Key Laboratory, National Health Commission of the People's Republic of China, Zhengzhou, China
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17
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Zhang M, Cheng X, Dang R, Zhang W, Zhang J, Yao Z. Lactate Deficit in an Alzheimer Disease Mouse Model: The Relationship With Neuronal Damage. J Neuropathol Exp Neurol 2019; 77:1163-1176. [PMID: 30383244 DOI: 10.1093/jnen/nly102] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/08/2018] [Indexed: 01/07/2023] Open
Abstract
Cerebral energy metabolism in Alzheimer disease (AD) has recently been given increasing attention. This study focuses on the alterations of cerebral lactate metabolism in the double-transgenic amyloid precursor protein/presenilin 1 (APP/PS1) mouse model of AD. Immunofluorescence staining and Western blotting analysis were used to identify the alterations of lactate content and lactate transporters (MCT1, MCT2, MCT4) in APP/PS1 mouse brains, which display amyloid beta plaques, reduced amounts of neurons and oligodendrocytes, and increased quantity of astrocytes. We found that lactate content and expressions of cerebral MCT1, MCT2, and MCT4 were decreased in APP/PS1 mice. In particular, lactate dehydrogenase A (LDHA) and B (LDHB) were reduced in neurons with increased ratios of LDHA and LDHB. This study suggests that the decreases of cerebral lactate content and lactate transporters may lead to the blockage of lactate transport from glia to neurons, resulting in neuronal lactate deficit. The increased ratio of neuronal LDHA and LDHB may represent a reaction of neurons to lactate deficit, although it cannot reverse the energy deficiency in neurons.
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Affiliation(s)
- Mao Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiaofang Cheng
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Ruozhi Dang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Weiwei Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jie Zhang
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhongxiang Yao
- Department of Physiology, Army Medical University (Third Military Medical University), Chongqing, China
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18
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Bordone MP, Salman MM, Titus HE, Amini E, Andersen JV, Chakraborti B, Diuba AV, Dubouskaya TG, Ehrke E, Espindola de Freitas A, Braga de Freitas G, Gonçalves RA, Gupta D, Gupta R, Ha SR, Hemming IA, Jaggar M, Jakobsen E, Kumari P, Lakkappa N, Marsh APL, Mitlöhner J, Ogawa Y, Paidi RK, Ribeiro FC, Salamian A, Saleem S, Sharma S, Silva JM, Singh S, Sulakhiya K, Tefera TW, Vafadari B, Yadav A, Yamazaki R, Seidenbecher CI. The energetic brain - A review from students to students. J Neurochem 2019; 151:139-165. [PMID: 31318452 DOI: 10.1111/jnc.14829] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/12/2022]
Abstract
The past 20 years have resulted in unprecedented progress in understanding brain energy metabolism and its role in health and disease. In this review, which was initiated at the 14th International Society for Neurochemistry Advanced School, we address the basic concepts of brain energy metabolism and approach the question of why the brain has high energy expenditure. Our review illustrates that the vertebrate brain has a high need for energy because of the high number of neurons and the need to maintain a delicate interplay between energy metabolism, neurotransmission, and plasticity. Disturbances to the energetic balance, to mitochondria quality control or to glia-neuron metabolic interaction may lead to brain circuit malfunction or even severe disorders of the CNS. We cover neuronal energy consumption in neural transmission and basic ('housekeeping') cellular processes. Additionally, we describe the most common (glucose) and alternative sources of energy namely glutamate, lactate, ketone bodies, and medium chain fatty acids. We discuss the multifaceted role of non-neuronal cells in the transport of energy substrates from circulation (pericytes and astrocytes) and in the supply (astrocytes and microglia) and usage of different energy fuels. Finally, we address pathological consequences of disrupted energy homeostasis in the CNS.
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Affiliation(s)
- Melina Paula Bordone
- Facultad de Farmacia y Bioquímica, Instituto de Investigaciones Farmacológicas (ININFA), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Haley E Titus
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Artem V Diuba
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Tatsiana G Dubouskaya
- Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Minsk, Belarus
| | - Eric Ehrke
- Centre for Biomolecular Interactions, University of Bremen, Bremen, Germany
| | - Andiara Espindola de Freitas
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, La Jolla, California, USA
| | | | | | | | - Richa Gupta
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Sharon R Ha
- Baylor College of Medicine, Houston, Texas, USA
| | - Isabel A Hemming
- Brain Growth and Disease Laboratory, The Harry Perkins Institute of Medical Research, Nedlands, Western Australia, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, Australia
| | - Minal Jaggar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Punita Kumari
- Defense Institute of Physiology and allied sciences, Defense Research and Development Organization, Timarpur, Delhi, India
| | - Navya Lakkappa
- Department of Pharmacology, JSS college of Pharmacy, Ooty, India
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany
| | - Yuki Ogawa
- The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | | | | | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Suraiya Saleem
- CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Sorabh Sharma
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Joana M Silva
- Life and Health Sciences Research Institute (ICVS), Medical School, University of Minho, Braga, Portugal
| | - Shripriya Singh
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Kunjbihari Sulakhiya
- Department of Pharmacy, Indira Gandhi National Tribal University, Amarkantak, India
| | - Tesfaye Wolde Tefera
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Behnam Vafadari
- Institute of environmental medicine, UNIKA-T, Technical University of Munich, Munich, Germany
| | - Anuradha Yadav
- CSIR-Indian Institute of Toxicology Research, Lucknow, India
| | - Reiji Yamazaki
- Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
| | - Constanze I Seidenbecher
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Otto von Guericke University, Magdeburg, Germany
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19
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Upregulation of the lactate transporter monocarboxylate transporter 1 at the blood-brain barrier in a rat model of attention-deficit/hyperactivity disorder suggests hyperactivity could be a form of self-treatment. Behav Brain Res 2019; 360:279-285. [DOI: 10.1016/j.bbr.2018.12.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/20/2018] [Accepted: 12/11/2018] [Indexed: 12/27/2022]
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20
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Chapp AD, Behnke JE, Driscoll KM, Fan Y, Hoban E, Shan Z, Zhang L, Chen QH. Acetate Mediates Alcohol Excitotoxicity in Dopaminergic-like PC12 Cells. ACS Chem Neurosci 2019; 10:235-245. [PMID: 30247872 DOI: 10.1021/acschemneuro.8b00189] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Neuronal excitotoxicity is the major cause of alcohol-related brain damage, yet the underlying mechanism remains poorly understood. Using dopaminergic-like PC12 cells, we evaluated the effect of N-methyl-d-aspartate receptors (NMDAR) on acetate-induced changes in PC12 cells: cell death, cytosolic calcium, and expression levels of the pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). Treatment of PC12 cells with increasing concentrations of acetate for 4 h caused a dose-dependent increase in the percentage of cells staining positive for cell death using propidium iodide (PI) exclusion and cytosolic reactive oxygen species (ROS) using cell ROX detection analyzed via flow cytometry. The EC50 value for acetate was calculated and found to be 4.40 mM for PI and 1.81 mM for ROS. Ethanol up to 100 mM had no apparent changes in the percent of cells staining positive for PI or ROS. Acetate (6 mM) treatment caused an increase in cytosolic calcium measured in real-time with Fluo-4AM, which was abolished by coapplication with the NMDAR blocker memantine (10 μM). Furthermore, cells treated with acetate (6 mM) for 4 h had increased expression levels of TNFα relative to control, which was abolished by coapplication of memantine (10 μM). Co-application of acetate (6 mM) and memantine had no apparent reduction in acetate-induced cell death. These findings suggest that acetate is capable of increasing cytosolic calcium concentrations and expression levels of the pro-inflammatory cytokine TNFα through an NMDAR-dependent mechanism. Cell death from acetate was not reduced through NMDAR blockade, suggesting alternative pathways independent of NMDAR activation for excitotoxicity.
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Affiliation(s)
- Andrew D. Chapp
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Jessica E. Behnke
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Kyle M. Driscoll
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Yuanyuan Fan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Eileen Hoban
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Li Zhang
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852, United States
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
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21
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Alvarez-Flores MP, Hébert A, Gouelle C, Geller S, Chudzinski-Tavassi AM, Pellerin L. Neuroprotective effect of rLosac on supplement-deprived mouse cultured cortical neurons involves maintenance of monocarboxylate transporter MCT2 protein levels. J Neurochem 2018; 148:80-96. [PMID: 30347438 DOI: 10.1111/jnc.14617] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 09/02/2018] [Accepted: 10/17/2018] [Indexed: 01/08/2023]
Abstract
The recombinant Lonomia obliqua Stuart-factor activator (rLosac) is a recombinant hemolin which belongs to the immunoglobulin superfamily of cell adhesion molecules. It is capable of inducing pro-survival activity in serum-deprived human umbilical vein endothelial cells (HUVECs) and fibroblasts by increasing mitochondrial metabolism. We hypothesize that it could promote neuronal survival by acting on neuroenergetics. Our study reveals that treatment of primary mouse cortical neurons cultured in neurobasal medium lacking B27 supplement with rLosac led to an enhancement of cell viability in a time- and concentration-dependent manner. In parallel, preserved or enhanced phosphorylation of Akt, p44, and p42 MAPK, as well as mTOR was observed following treatment with rLosac. During deprivation, as assessed by western blot and qRT-PCR, protein and mRNA expression of MCT2 (the predominant neuronal monocarboxylate transporter allowing lactate use as an alternative energy substrate) decreased significantly in B27 supplement-deprived cortical neurons and was hardly detected after 24 h of deprivation. Interestingly, rLosac maintained MCT2 protein expression after 24 h of deprivation including at the cell surface without preventing mRNA loss. MCT2 knockdown reduced rLosac-enhanced cell viability, confirming its involvement in rLosac effect. Enhanced uptake of lactate was detected following rLosac treatment and might contribute to rLosac-enhanced viability during deprivation. In the presence of both lactate and rLosac, cell viability was higher than in the presence of lactate alone. Our observations suggest that rLosac promotes cell viability in stressed (B27 supplement-deprived) neurons by facilitating the use of lactate as energy substrate via the preservation of MCT2 protein expression. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Miryam P Alvarez-Flores
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.,Laboratory of Molecular Biology - Centre of Excellence in New Target Discover CENTD, Butantan Institute, São Paulo, Brazil
| | - Audrey Hébert
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Cathy Gouelle
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Sarah Geller
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Ana M Chudzinski-Tavassi
- Laboratory of Molecular Biology - Centre of Excellence in New Target Discover CENTD, Butantan Institute, São Paulo, Brazil
| | - Luc Pellerin
- Department of Physiology, University of Lausanne, Lausanne, Switzerland.,Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536 CNRS, LabEx TRAIL-IBIO, Université de Bordeaux, Bordeaux Cedex, France
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22
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Watts ME, Pocock R, Claudianos C. Brain Energy and Oxygen Metabolism: Emerging Role in Normal Function and Disease. Front Mol Neurosci 2018; 11:216. [PMID: 29988368 PMCID: PMC6023993 DOI: 10.3389/fnmol.2018.00216] [Citation(s) in RCA: 200] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/01/2018] [Indexed: 01/09/2023] Open
Abstract
Dynamic metabolic changes occurring in neurons are critically important in directing brain plasticity and cognitive function. In other tissue types, disruptions to metabolism and the resultant changes in cellular oxidative state, such as increased reactive oxygen species (ROS) or induction of hypoxia, are associated with cellular stress. In the brain however, where drastic metabolic shifts occur to support physiological processes, subsequent changes to cellular oxidative state and induction of transcriptional sensors of oxidative stress likely play a significant role in regulating physiological neuronal function. Understanding the role of metabolism and metabolically-regulated genes in neuronal function will be critical in elucidating how cognitive functions are disrupted in pathological conditions where neuronal metabolism is affected. Here, we discuss known mechanisms regulating neuronal metabolism as well as the role of hypoxia and oxidative stress during normal and disrupted neuronal function. We also summarize recent studies implicating a role for metabolism in regulating neuronal plasticity as an emerging neuroscience paradigm.
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Affiliation(s)
- Michelle E Watts
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, Australia
| | - Roger Pocock
- Development and Stem Cells Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, St. Lucia, QLD, Australia.,Centre for Mental Health Research, The Australian National University, Canberra, ACT, Australia
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23
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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24
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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25
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 916] [Impact Index Per Article: 152.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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26
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Lai Q, Du W, Wu J, Wang X, Li X, Qu X, Wu X, Dong F, Yao R, Fan H. H3K9ac and HDAC2 Activity Are Involved in the Expression of Monocarboxylate Transporter 1 in Oligodendrocyte. Front Mol Neurosci 2017; 10:376. [PMID: 29184483 PMCID: PMC5694447 DOI: 10.3389/fnmol.2017.00376] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/27/2017] [Indexed: 01/09/2023] Open
Abstract
Recently, it is reported that monocarboxylate transporter 1 (MCT1) plays crucial role in oligodendrocyte differentiation and myelination. We found that MCT1 is strongly expressed in oligodendrocyte but weakly expressed in oligodendrocyte precursors (OPCs), and the underlying mechanisms remain elusive. Histone deacetylases (HDACs) activity is required for induction of oligodendrocyte differentiation and maturation. We asked whether HDACs are involved in the regulation of MCT1 expression. This work revealed that the acetylation level of histone H3K9 (H3K9ac) was much higher in mct1 gene (Slc16a1) promoter in OPCs than that in oligodendrocyte. H3K9ac regulates MCT1 expression was confirmed by HDAC acetyltransferase inhibitors trichostatin A and curcumin. Of note, there was a negative correlation between H3K9ac and MCT1 expression in oligodendrocyte. Further, we found that the levels of HDAC1, 2, and 3 protein in oligodendrocyte were obviously higher than those in OPCs. However, specific knockdown of HDAC2 but not HDAC1 and HDAC3 significantly decreased the expression of MCT1 in oligodendrocyte. Conversely, overexpression of HDAC2 remarkably enhanced the expression of MCT1. The results imply that HDAC2 is involved in H3K9ac modification which regulates the expression of MCT1 during the development of oligodendrocyte.
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Affiliation(s)
- Qingwei Lai
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Neurology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Wantong Du
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jian Wu
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xiao Wang
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Neurology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xinyu Li
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xuebin Qu
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xiuxiang Wu
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Fuxing Dong
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Ruiqin Yao
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Hongbin Fan
- Xuzhou Key Laboratory of Neurobiology, Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Neurology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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27
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Liu L, MacKenzie KR, Putluri N, Maletić-Savatić M, Bellen HJ. The Glia-Neuron Lactate Shuttle and Elevated ROS Promote Lipid Synthesis in Neurons and Lipid Droplet Accumulation in Glia via APOE/D. Cell Metab 2017; 26:719-737.e6. [PMID: 28965825 PMCID: PMC5677551 DOI: 10.1016/j.cmet.2017.08.024] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/21/2017] [Accepted: 08/30/2017] [Indexed: 01/04/2023]
Abstract
Elevated reactive oxygen species (ROS) induce the formation of lipids in neurons that are transferred to glia, where they form lipid droplets (LDs). We show that glial and neuronal monocarboxylate transporters (MCTs), fatty acid transport proteins (FATPs), and apolipoproteins are critical for glial LD formation. MCTs enable glia to secrete and neurons to absorb lactate, which is converted to pyruvate and acetyl-CoA in neurons. Lactate metabolites provide a substrate for synthesis of fatty acids, which are processed and transferred to glia by FATP and apolipoproteins. In the presence of high ROS, inhibiting lactate transfer or lowering FATP or apolipoprotein levels decreases glial LD accumulation in flies and in primary mouse glial-neuronal cultures. We show that human APOE can substitute for a fly glial apolipoprotein and that APOE4, an Alzheimer's disease susceptibility allele, is impaired in lipid transport and promotes neurodegeneration, providing insights into disease mechanisms.
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Affiliation(s)
- Lucy Liu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kevin R MacKenzie
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology and Advanced Technology Cor, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mirjana Maletić-Savatić
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA
| | - Hugo J Bellen
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
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28
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Jin C, Gao L, Li Y, Wu S, Lu X, Yang J, Cai Y. Lanthanum damages learning and memory and suppresses astrocyte–neuron lactate shuttle in rat hippocampus. Exp Brain Res 2017; 235:3817-3832. [DOI: 10.1007/s00221-017-5102-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 10/03/2017] [Indexed: 12/26/2022]
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29
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Forero-Quintero LS, Deitmer JW, Becker HM. Reduction of epileptiform activity in ketogenic mice: The role of monocarboxylate transporters. Sci Rep 2017; 7:4900. [PMID: 28687765 PMCID: PMC5501801 DOI: 10.1038/s41598-017-05054-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/23/2017] [Indexed: 02/05/2023] Open
Abstract
Epilepsy is a chronic neurological disorder that affects approximately 50 million people worldwide. Ketogenic diet (KD) can be a very effective treatment for intractable epilepsy. Potential mechanisms of action for KD have been proposed, including the re-balance among excitatory and inhibitory neurotransmission and decrease in the glycolytic rate in brain cells. KD has been shown to have an effect on the expression pattern of monocarboxylate transporters (MCT), however, it is unknown whether MCT transport activity is affected by KD and linked to the reduction of seizures during KD. Therefore, we studied the influence of KD on MCT transport activity and the role of MCTs during epileptiform activity. Our results showed a decrease in the epileptiform activity in cortical slices from mice fed on KD and in the presence of beta-hydroxybutyrate. KD increased transport capacity for ketone bodies and lactate in cortical astrocytes by raising the MCT1 expression level. Inhibition of MCT1 and MCT2 in control conditions decreases epileptiform activity, while in KD it induced an increase in epileptiform activity. Our results suggest that MCTs not only play an important role in the transport of ketone bodies, but also in the modulation of brain energy metabolism under normal and ketogenic conditions.
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Affiliation(s)
- Linda S Forero-Quintero
- Division of General Zoology, Department of Biology, University of Kaiserslautern, P.O. Box 3049, D-67653, Kaiserslautern, Germany
| | - Joachim W Deitmer
- Division of General Zoology, Department of Biology, University of Kaiserslautern, P.O. Box 3049, D-67653, Kaiserslautern, Germany
| | - Holger M Becker
- Division of General Zoology, Department of Biology, University of Kaiserslautern, P.O. Box 3049, D-67653, Kaiserslautern, Germany.
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30
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Briski KP, Alhamami HN, Alshamrani A, Mandal SK, Shakya M, Ibrahim MHH. Sex Differences and Role of Estradiol in Hypoglycemia-Associated Counter-Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1043:359-383. [PMID: 29224103 DOI: 10.1007/978-3-319-70178-3_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vital nerve cell functions, including maintenance of transmembrane voltage and information transfer, occur at high energy expense. Inadequate provision of the obligate metabolic fuel glucose exposes neurons to risk of dysfunction or injury. Clinical hypoglycemia rarely occurs in nondiabetic individuals but is an unfortunate regular occurrence in patients with type 1 or advanced insulin-treated type 2 diabetes mellitus. Requisite strict glycemic control, involving treatment with insulin, sulfonylureas, or glinides, can cause frequent episodes of iatrogenic hypoglycemia due to defective counter-regulation, including reduced glycemic thresholds and diminished magnitude of motor responses. Multiple components of the body's far-reaching energy balance regulatory network, including the hindbrain dorsal vagal complex, provide dynamic readout of cellular energetic disequilibrium, signals that are utilized by the hypothalamus to shape counterregulatory autonomic, neuroendocrine, and behavioral outflow toward restoration of glucostasis. The ovarian steroid hormone 17β-estradiol acts on central substrates to preserve nerve cell energy stability brain-wide, thereby providing neuroprotection against bio-energetic insults such as neurodegenerative diseases and acute brain ischemia. The current review highlights recent evidence implicating estrogen in gluco-regulation in females by control of hindbrain metabolic sensor screening and signaling of hypoglycemia-associated neuro-energetic instability. It is anticipated that new understanding of the mechanistic basis of how estradiol influences metabolic sensory input from this critical brain locus to discrete downstream regulatory network substrates will likely reveal viable new molecular targets for therapeutic simulation of hormone actions that promote positive neuronal metabolic state during acute and recurring hypoglycemia.
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Affiliation(s)
- Karen P Briski
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA.
| | - Hussain N Alhamami
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA
| | - Ayed Alshamrani
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA
| | - Santosh K Mandal
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA
| | - Manita Shakya
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA
| | - Mostafa H H Ibrahim
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA, USA
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31
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Pérez-Escuredo J, Van Hée VF, Sboarina M, Falces J, Payen VL, Pellerin L, Sonveaux P. Monocarboxylate transporters in the brain and in cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:2481-97. [PMID: 26993058 PMCID: PMC4990061 DOI: 10.1016/j.bbamcr.2016.03.013] [Citation(s) in RCA: 267] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 03/01/2016] [Accepted: 03/12/2016] [Indexed: 12/20/2022]
Abstract
Monocarboxylate transporters (MCTs) constitute a family of 14 members among which MCT1-4 facilitate the passive transport of monocarboxylates such as lactate, pyruvate and ketone bodies together with protons across cell membranes. Their anchorage and activity at the plasma membrane requires interaction with chaperon protein such as basigin/CD147 and embigin/gp70. MCT1-4 are expressed in different tissues where they play important roles in physiological and pathological processes. This review focuses on the brain and on cancer. In the brain, MCTs control the delivery of lactate, produced by astrocytes, to neurons, where it is used as an oxidative fuel. Consequently, MCT dysfunctions are associated with pathologies of the central nervous system encompassing neurodegeneration and cognitive defects, epilepsy and metabolic disorders. In tumors, MCTs control the exchange of lactate and other monocarboxylates between glycolytic and oxidative cancer cells, between stromal and cancer cells and between glycolytic cells and endothelial cells. Lactate is not only a metabolic waste for glycolytic cells and a metabolic fuel for oxidative cells, but it also behaves as a signaling agent that promotes angiogenesis and as an immunosuppressive metabolite. Because MCTs gate the activities of lactate, drugs targeting these transporters have been developed that could constitute new anticancer treatments. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Jhudit Pérez-Escuredo
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium
| | - Vincent F Van Hée
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium
| | - Martina Sboarina
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium
| | - Jorge Falces
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium
| | - Valéry L Payen
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium
| | - Luc Pellerin
- Laboratory of Neuroenergetics, Department of Physiology, University of Lausanne, Rue du Bugnon 7, 1005 Lausanne, Switzerland.
| | - Pierre Sonveaux
- Pole of Pharmacology, Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain (UCL), Avenue Emmanuel Mounier 52 box B1.53.09, 1200 Brussels, Belgium.
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32
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Logica T, Riviere S, Holubiec MI, Castilla R, Barreto GE, Capani F. Metabolic Changes Following Perinatal Asphyxia: Role of Astrocytes and Their Interaction with Neurons. Front Aging Neurosci 2016; 8:116. [PMID: 27445788 PMCID: PMC4921470 DOI: 10.3389/fnagi.2016.00116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/03/2016] [Indexed: 11/13/2022] Open
Abstract
Perinatal Asphyxia (PA) represents an important cause of severe neurological deficits including delayed mental and motor development, epilepsy, major cognitive deficits and blindness. The interaction between neurons, astrocytes and endothelial cells plays a central role coupling energy supply with changes in neuronal activity. Traditionally, experimental research focused on neurons, whereas astrocytes have been more related to the damage mechanisms of PA. Astrocytes carry out a number of functions that are critical to normal nervous system function, including uptake of neurotransmitters, regulation of pH and ion concentrations, and metabolic support for neurons. In this work, we aim to review metabolic neuron-astrocyte interactions with the purpose of encourage further research in this area in the context of PA, which is highly complex and its mechanisms and pathways have not been fully elucidated to this day.
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Affiliation(s)
- Tamara Logica
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Facultad de Medicina, Instituto de Investigaciones Cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), UBA-CONICET, CABA Buenos Aires, Argentina
| | - Stephanie Riviere
- Laboratorio de Biología Molecular, Facultad de Medicina, Instituto de Investigaciones cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), UBA-CONICET, CABA Buenos Aires, Argentina
| | - Mariana I Holubiec
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Facultad de Medicina, Instituto de Investigaciones Cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), UBA-CONICET, CABA Buenos Aires, Argentina
| | - Rocío Castilla
- Laboratorio de Biología Molecular, Facultad de Medicina, Instituto de Investigaciones cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), UBA-CONICET, CABA Buenos Aires, Argentina
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana Bogotá Bogotá, Colombia
| | - Francisco Capani
- Laboratorio de Citoarquitectura y Plasticidad Neuronal, Facultad de Medicina, Instituto de Investigaciones Cardiológicas Prof. Dr. Alberto C. Taquini (ININCA), UBA-CONICET, CABABuenos Aires, Argentina; Departamento de Biología, Universidad Argentina JF KennedyBuenos Aires, Argentina; Investigador Asociado, Universidad Autónoma de ChileSantiago, Chile
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33
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Rosafio K, Castillo X, Hirt L, Pellerin L. Cell-specific modulation of monocarboxylate transporter expression contributes to the metabolic reprograming taking place following cerebral ischemia. Neuroscience 2016; 317:108-20. [DOI: 10.1016/j.neuroscience.2015.12.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/17/2015] [Accepted: 12/29/2015] [Indexed: 01/23/2023]
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34
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Mächler P, Wyss MT, Elsayed M, Stobart J, Gutierrez R, von Faber-Castell A, Kaelin V, Zuend M, San Martín A, Romero-Gómez I, Baeza-Lehnert F, Lengacher S, Schneider BL, Aebischer P, Magistretti PJ, Barros LF, Weber B. In Vivo Evidence for a Lactate Gradient from Astrocytes to Neurons. Cell Metab 2016; 23:94-102. [PMID: 26698914 DOI: 10.1016/j.cmet.2015.10.010] [Citation(s) in RCA: 374] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/21/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022]
Abstract
Investigating lactate dynamics in brain tissue is challenging, partly because in vivo data at cellular resolution are not available. We monitored lactate in cortical astrocytes and neurons of mice using the genetically encoded FRET sensor Laconic in combination with two-photon microscopy. An intravenous lactate injection rapidly increased the Laconic signal in both astrocytes and neurons, demonstrating high lactate permeability across tissue. The signal increase was significantly smaller in astrocytes, pointing to higher basal lactate levels in these cells, confirmed by a one-point calibration protocol. Trans-acceleration of the monocarboxylate transporter with pyruvate was able to reduce intracellular lactate in astrocytes but not in neurons. Collectively, these data provide in vivo evidence for a lactate gradient from astrocytes to neurons. This gradient is a prerequisite for a carrier-mediated lactate flux from astrocytes to neurons and thus supports the astrocyte-neuron lactate shuttle model, in which astrocyte-derived lactate acts as an energy substrate for neurons.
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Affiliation(s)
- Philipp Mächler
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Matthias T Wyss
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Maha Elsayed
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Jillian Stobart
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | - Robin Gutierrez
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Centro de Estudios Científicos, Valdivia 5110466, Chile
| | | | - Vincens Kaelin
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland
| | | | | | | | - Sylvain Lengacher
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bernard L Schneider
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Patrick Aebischer
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Pierre J Magistretti
- Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
| | | | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8092 Zurich, Switzerland.
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Hong S, Ahn JY, Cho GS, Kim IH, Cho JH, Ahn JH, Park JH, Won MH, Chen BH, Shin BN, Tae HJ, Park SM, Cho JH, Choi SY, Lee JC. Monocarboxylate transporter 4 plays a significant role in the neuroprotective mechanism of ischemic preconditioning in transient cerebral ischemia. Neural Regen Res 2015; 10:1604-11. [PMID: 26692857 PMCID: PMC4660753 DOI: 10.4103/1673-5374.167757] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Monocarboxylate transporters (MCTs), which carry monocarboxylates such as lactate across biological membranes, have been associated with cerebral ischemia/reperfusion process. In this study, we studied the effect of ischemic preconditioning (IPC) on MCT4 immunoreactivity after 5 minutes of transient cerebral ischemia in the gerbil. Animals were randomly designated to four groups (sham-operated group, ischemia only group, IPC + sham-operated group and IPC + ischemia group). A serious loss of neuron was found in the stratum pyramidale of the hippocampal CA1 region (CA1), not CA2/3, of the ischemia-only group at 5 days post-ischemia; however, in the IPC + ischemia groups, neurons in the stratum pyramidale of the CA1 were well protected. Weak MCT4 immunoreactivity was found in the stratum pyramidale of the CA1 in the sham-operated group. MCT4 immunoreactivity in the stratum pyramidale began to decrease at 2 days post-ischemia and was hardly detected at 5 days post-ischemia; at this time point, MCT4 immunoreactivity was newly expressed in astrocytes. In the IPC + sham-operated group, MCT4 immunoreactivity in the stratum pyramidale of the CA1 was increased compared with the sham-operated group, and, in the IPC + ischemia group, MCT4 immunoreactivity was also increased in the stratum pyramidale compared with the ischemia only group. Briefly, present findings show that IPC apparently protected CA1 pyramidal neurons and increased or maintained MCT4 expression in the stratum pyramidale of the CA1 after transient cerebral ischemia. Our findings suggest that MCT4 appears to play a significant role in the neuroprotective mechanism of IPC in the gerbil with transient cerebral ischemia.
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Affiliation(s)
- Seongkweon Hong
- Department of Surgery, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Ji Yun Ahn
- Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, South Korea ; Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Geum-Sil Cho
- Department of Neuroscience, College of Medicine, Korea University, Seoul, South Korea
| | - In Hye Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Jeong Hwi Cho
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Ji Hyeon Ahn
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Joon Ha Park
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Bai Hui Chen
- Department of Physiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Bich-Na Shin
- Department of Physiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Hyun-Jin Tae
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, South Korea
| | - Seung Min Park
- Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang, South Korea ; Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon, South Korea
| | - Soo Young Choi
- Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, South Korea
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, South Korea
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Is L-lactate a novel signaling molecule in the brain? J Cereb Blood Flow Metab 2015; 35:1069-75. [PMID: 25920953 PMCID: PMC4640281 DOI: 10.1038/jcbfm.2015.77] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/24/2015] [Accepted: 03/24/2015] [Indexed: 01/01/2023]
Abstract
In the brain, L-lactate is produced by both neurons and astrocytes. There is no doubt that neurons use L-lactate as a supplementary fuel although the importance of this energy source is disputed. Irrespective of its caloric value, L-lactate might also have a signaling role in the brain. Here, we review several current hypotheses of L-lactate mediated signaling. Some proposed mechanisms require L-lactate entry into the neurons leading to a shift in ATP/ADP ratio or redox state. Others postulate interaction with either known receptor HCA1 (GPR81) or a novel, yet unidentified receptor. We argue that the sensitivity of any such mechanism has to match the concentration range of extracellular L-lactate, which is less than ~1.5 mmol/L under physiologic conditions. From that point of view, some of the proposed mechanisms require supraphysiologic levels of L-lactate and could be engaged during ischemia or seizures when L-lactate concentration rises dramatically. Currently, we do not know whether L-lactate production in the brain occurs in microdomains, which might create higher than average local concentrations. Nevertheless, it is clear that in the brain, as in the peripheral tissues, L-lactate is not only used as a source of energy but also acts as a signaling molecule.
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Kaczor P, Rakus D, Mozrzymas JW. Neuron-astrocyte interaction enhance GABAergic synaptic transmission in a manner dependent on key metabolic enzymes. Front Cell Neurosci 2015; 9:120. [PMID: 25914620 PMCID: PMC4391237 DOI: 10.3389/fncel.2015.00120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/17/2015] [Indexed: 11/21/2022] Open
Abstract
Gamma aminobutric acid (GABA) is the major inhibitory neurotransmitter in the adult brain and mechanisms of GABAergic inhibition have been intensely investigated in the past decades. Recent studies provided evidence for an important role of astrocytes in shaping GABAergic currents. One of the most obvious, but yet poorly understood, mechanisms of the cross-talk between GABAergic currents and astrocytes is metabolism including neurotransmitter homeostasis. In particular, how modulation of GABAergic currents by astrocytes depends on key enzymes involved in cellular metabolism remains largely unknown. To address this issue, we have considered two simple models of neuronal culture (NC): nominally astrocyte-free NC and neuronal-astrocytic co-cultures (ANCC). Miniature Inhibitory Postsynaptic Currents (mIPSCs) were recorded in control conditions and in the presence of different enzyme blockers. We report that enrichment of NC with astrocytes results in a marked increase in mIPSC frequency. This enhancement of GABAergic activity was accompanied by increased number of GAD65 and vGAT puncta, indicating that at least a part of the frequency enhancement was due to increased number of synaptic contacts. Inhibition of glutamine synthetase (Glns) (with MSO) strongly reduced mIPSC frequency in ANCC but had no effect in NC. Moreover, treatment of ANCC with inhibitor of glycogen phosphorylase (Gys) (BAYU6751) or with selective inhibitor of astrocytic Krebs cycle, fluoroacetate, resulted in a marked reduction of mIPSC frequency in ANCC having no effect in NC. We conclude that GABAergic synaptic transmission strongly depends on neuron-astrocyte interaction in a manner dependent on key metabolic enzymes as well as on the Krebs cycle.
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Affiliation(s)
- Przemysław Kaczor
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland
| | - Dariusz Rakus
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland
| | - Jerzy W Mozrzymas
- Department of Animal Molecular Physiology, Wroclaw University Wroclaw, Poland ; Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University Wroclaw, Poland
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Álvarez Z, Hyroššová P, Perales JC, Alcántara S. Neuronal Progenitor Maintenance Requires Lactate Metabolism and PEPCK-M-Directed Cataplerosis. Cereb Cortex 2014; 26:1046-58. [PMID: 25452568 DOI: 10.1093/cercor/bhu281] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
This study investigated the metabolic requirements for neuronal progenitor maintenance in vitro and in vivo by examining the metabolic adaptations that support neuronal progenitors and neural stem cells (NSCs) in their undifferentiated state. We demonstrate that neuronal progenitors are strictly dependent on lactate metabolism, while glucose induces their neuronal differentiation. Lactate signaling is not by itself capable of maintaining the progenitor phenotype. The consequences of lactate metabolism include increased mitochondrial and oxidative metabolism, with a strict reliance on cataplerosis through the mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M) pathway to support anabolic functions, such as the production of extracellular matrix. In vivo, lactate maintains/induces populations of postnatal neuronal progenitors/NSCs in a PEPCK-M-dependent manner. Taken together, our data demonstrate that, lactate alone or together with other physical/biochemical cues maintain NSCs/progenitors with a metabolic signature that is classically found in tissues with high anabolic capacity.
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Affiliation(s)
- Zaida Álvarez
- Institute for Bioengineering of Catalonia-IBEC, Barcelona, Spain Department of Pathology and Experimental Therapeutics CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain
| | - Petra Hyroššová
- Department of Physiological Sciences II, Medical School (Bellvitge Campus), University of Barcelona-UB, Barcelona, Spain
| | - José Carlos Perales
- Department of Physiological Sciences II, Medical School (Bellvitge Campus), University of Barcelona-UB, Barcelona, Spain
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Stecker MM, Stevenson MR. Anoxia-induced changes in optimal substrate for peripheral nerve. Neuroscience 2014; 284:653-667. [PMID: 25451283 DOI: 10.1016/j.neuroscience.2014.10.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 12/20/2022]
Abstract
Hyperglycemia accentuates the injury produced by anoxia both in the central and peripheral nervous system. To understand whether this is a consequence of changes in metabolic pathways produced by anoxia, the effect of the metabolic substrate used by the rat peripheral nerve on the nerve action potential (NAP) was studied in the presence and absence of anoxia. In the continuously oxygenated state, the NAP was well preserved with glucose, lactate, as well as with high concentrations of sorbitol and fructose but not β-hydroxybutyrate, acetate or galactose. With intermittent anoxia, the pattern of substrate effects on the NAP changed markedly so that low concentrations of fructose became able to support neurophysiologic activity but not high concentrations of glucose. These alterations occurred gradually with repeated episodes of anoxia as reflected by the progressive increase in the time needed for the NAP to disappear during anoxia when using glucose as substrate. This "preconditioning" effect was not seen with other substrates and an opposite effect was seen with lactate. In fact, the rate at which the NAP disappeared during anoxia was not simply related to degree of recovery after anoxia. These are distinct phenomena. For example, the NAP persisted longest during anoxia in the setting of hyperglycemia but this was the state in which the anoxic damage was most severe. Correlating the results with existing literature on the metabolic functions of Schwann cells and axons generates testable hypotheses for the mechanism of hyperglycemic damage during anoxia and lead to discussions of the role for a metabolic shuttle between Schwann cells and axons as well as a potential important role of glycogen.
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Affiliation(s)
- M M Stecker
- Winthrop University Hospital, Mineola, NY 11530, United States.
| | - M R Stevenson
- Winthrop University Hospital, Mineola, NY 11530, United States
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Sandström von Tobel J, Zoia D, Althaus J, Antinori P, Mermoud J, Pak HS, Scherl A, Monnet-Tschudi F. Immediate and delayed effects of subchronic Paraquat exposure during an early differentiation stage in 3D-rat brain cell cultures. Toxicol Lett 2014; 230:188-97. [DOI: 10.1016/j.toxlet.2014.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/30/2014] [Accepted: 02/02/2014] [Indexed: 11/28/2022]
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Beesley PW, Herrera-Molina R, Smalla KH, Seidenbecher C. The Neuroplastin adhesion molecules: key regulators of neuronal plasticity and synaptic function. J Neurochem 2014; 131:268-83. [PMID: 25040546 DOI: 10.1111/jnc.12816] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/02/2014] [Accepted: 07/03/2014] [Indexed: 01/21/2023]
Abstract
The Neuroplastins Np65 and Np55 are neuronal and synapse-enriched immunoglobulin superfamily molecules that play important roles in a number of key neuronal and synaptic functions including, for Np65, cell adhesion. In this review we focus on the physiological roles of the Neuroplastins in promoting neurite outgrowth, regulating the structure and function of both inhibitory and excitatory synapses in brain, and in neuronal and synaptic plasticity. We discuss the underlying molecular and cellular mechanisms by which the Neuroplastins exert their physiological effects and how these are dependent upon the structural features of Np65 and Np55, which enable them to bind to a diverse range of protein partners. In turn this enables the Neuroplastins to interact with a number of key neuronal signalling cascades. These include: binding to and activation of the fibroblast growth factor receptor; Np65 trans-homophilic binding leading to activation of p38 MAPK and internalization of glutamate (GluR1) receptor subunits; acting as accessory proteins for monocarboxylate transporters, thus affecting neuronal energy supply, and binding to GABAA α1, 2 and 5 subunits, thus regulating the composition and localization of GABAA receptors. An emerging theme is the role of the Neuroplastins in regulating the trafficking and subcellular localization of specific binding partners. We also discuss the involvement of Neuroplastins in a number of pathophysiological conditions, including ischaemia, schizophrenia and breast cancer and the role of a single nucleotide polymorphism in the human Neuroplastin (NPTN) gene locus in impairment of cortical development and cognitive functions. Neuroplastins are neuronal cell adhesion molecules, which induce neurite outgrowth and play important roles in synaptic maturation and plasticity. This review summarizes the functional implications of Neuroplastins for correct synaptic membrane protein localization, neuronal energy supply, expression of LTP and LTD, animal and human behaviour, and pathophysiology and disease. It focuses particularly on Neuroplastin binding partners and signalling mechanisms, and proposes perspectives for future research on these important immunoglobulin superfamily members.
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Affiliation(s)
- Philip W Beesley
- School of Biological Sciences, Royal Holloway University of London, Egham, UK
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42
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Tseng YC, Liu ST, Hu MY, Chen RD, Lee JR, Hwang PP. Brain functioning under acute hypothermic stress supported by dynamic monocarboxylate utilization and transport in ectothermic fish. Front Zool 2014. [DOI: 10.1186/s12983-014-0053-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Transport of Lactate: Characterization of the Transporters Involved in Transport at the Plasma Membrane by Heterologous Protein Expression in Xenopus Oocytes. BRAIN ENERGY METABOLISM 2014. [DOI: 10.1007/978-1-4939-1059-5_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Beesley P, Kraus M, Parolaro N. The neuroplastins: multifunctional neuronal adhesion molecules--involvement in behaviour and disease. ADVANCES IN NEUROBIOLOGY 2014; 8:61-89. [PMID: 25300133 DOI: 10.1007/978-1-4614-8090-7_4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The neuroplastins np65 and np55 are neuronal and synapse-enriched immunoglobulin (Ig) superfamily cell adhesion molecules that contain 3 and 2 Ig domains, respectively. Np65 is neuron specific whereas np55 is expressed in many tissues. They are multifunctional proteins whose physiological roles are defined by the partner proteins they bind to and the signalling pathways they activate. The neuroplastins are implicated in activity-dependent long-term synaptic plasticity. Thus neuroplastin-specific antibodies and a recombinant peptide inhibit long-term potentiation in hippocampal neurones. This is mediated by activation of the p38MAP kinase signalling pathway, resulting in the downregulation of the surface expression of GluR1 receptors. Np65, but not np55, exhibits trans-homophilic binding. Both np65 and np55 induce neurite outgrowth and both activate the FGF receptor and associated downstream signalling pathways. Np65 binds to and colocalises with GABA(A) receptor subtypes and may play a role in anchoring them to specific synaptic and extrasynaptic sites. Most recently the neuroplastins have been shown to chaperone and support the monocarboxylate transporter MCT2 in transporting lactate across the neuronal plasma membrane. Thus the neuroplastins are multifunctional adhesion molecules which support neurite outgrowth, modulate long-term activity-dependent synaptic plasticity, regulate surface expression of GluR1 receptors, modulate GABA(A) receptor localisation, and play a key role in delivery of monocarboxylate energy substrates both to the synapse and to extrasynaptic sites. The diverse functions and range of signalling pathways activated by the neuroplastins suggest that they are important in modulating behaviour and in relation to human disease.
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Wilson MC, Kraus M, Marzban H, Sarna JR, Wang Y, Hawkes R, Halestrap AP, Beesley PW. The neuroplastin adhesion molecules are accessory proteins that chaperone the monocarboxylate transporter MCT2 to the neuronal cell surface. PLoS One 2013; 8:e78654. [PMID: 24260123 PMCID: PMC3832594 DOI: 10.1371/journal.pone.0078654] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/13/2013] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The neuroplastins np65 and np55 are two synapse-enriched immunoglobulin (Ig) superfamily adhesion molecules that contain 3 and 2 Ig domains respectively. Np65 is implicated in long term, activity dependent synaptic plasticity, including LTP. Np65 regulates the surface expression of GluR1 receptor subunits and the localisation of GABA(A) receptor subtypes in hippocampal neurones. The brain is dependent not only on glucose but on monocarboxylates as sources of energy. The. monocarboxylate transporters (MCTs) 1-4 are responsible for the rapid proton-linked translocation of monocarboxylates including pyruvate and lactate across the plasma membrane and require association with either embigin or basigin, proteins closely related to neuroplastin, for plasma membrane expression and activity. MCT2 plays a key role in providing lactate as an energy source to neurons. METHODOLOGY/FINDINGS Here we use co-transfection of neuroplastins and monocarboxylate transporters into COS-7 cells to demonstrate that neuroplastins can act as ancillary proteins for MCT2. We also show that Xenopus laevis oocytes contain endogenous neuroplastin and its knockdown with antisense RNA reduces the surface expression of MCT2 and associated lactate transport. Immunocytochemical studies show that MCT2 and the neuroplastins are co-localised in rat cerebellum. Strikingly neuroplastin and MCT2 are enriched in the same parasagittal zebrin II-negative stripes. CONCLUSIONS These data strongly suggest that neuroplastins act as key ancillary proteins for MCT2 cell surface localisation and activity in some neuronal populations, thus playing an important role in facilitating the uptake of lactate for use as a respiratory fuel.
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Affiliation(s)
| | - Michaela Kraus
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
| | - Hassan Marzban
- Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Justyna R. Sarna
- Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Yisong Wang
- Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Richard Hawkes
- Department of Cell Biology and Anatomy and Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | | | - Philip W. Beesley
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
- * E-mail:
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Saab AS, Tzvetanova ID, Nave KA. The role of myelin and oligodendrocytes in axonal energy metabolism. Curr Opin Neurobiol 2013; 23:1065-72. [PMID: 24094633 DOI: 10.1016/j.conb.2013.09.008] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 09/14/2013] [Accepted: 09/16/2013] [Indexed: 12/15/2022]
Abstract
In vertebrates, the myelination of long axons by oligodendrocytes and Schwann cells enables rapid impulse propagation. However, myelin sheaths are not only passive insulators. Oligodendrocytes are also known to support axonal functions and long-term integrity. Some of the underlying mechanisms have now been identified. It could be shown that oligodendrocytes can survive in vivo by aerobic glycolysis. Myelinating oligodendrocytes release lactate through the monocarboxylate transporter MCT1. Lactate is then utilized by axons for mitochondrial ATP generation. Studying axo-glial signalling and energy metabolism will lead to a better understanding of neurodegenerative diseases, in which axonal energy metabolism fails. These include neurological disorders as diverse as multiple sclerosis, leukodystrophies, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Aiman S Saab
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen, Germany
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Tulpule K, Dringen R. Formaldehyde in brain: an overlooked player in neurodegeneration? J Neurochem 2013; 127:7-21. [PMID: 23800365 DOI: 10.1111/jnc.12356] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 06/12/2013] [Accepted: 06/21/2013] [Indexed: 02/06/2023]
Abstract
Formaldehyde is an environmental pollutant that is also generated in substantial amounts in the human body during normal metabolism. This aldehyde is a well-established neurotoxin that affects memory, learning, and behavior. In addition, in several pathological conditions, including Alzheimer's disease, an increase in the expression of formaldehyde-generating enzymes and elevated levels of formaldehyde in brain have been reported. This article gives an overview on the current knowledge on the generation and metabolism of formaldehyde in brain cells as well as on formaldehyde-induced alterations in metabolic processes. Brain cells have the potential to generate and to dispose formaldehyde. In culture, both astrocytes and neurons efficiently oxidize formaldehyde to formate which can be exported or further oxidized. Although moderate concentrations of formaldehyde are not acutely toxic for brain cells, exposure to formaldehyde severely affects their metabolism as demonstrated by the formaldehyde-induced acceleration of glycolytic flux and by the rapid multidrug resistance protein 1-mediated export of glutathione from both astrocytes and neurons. These formaldehyde-induced alterations in the metabolism of brain cells may contribute to the impaired cognitive performance observed after formaldehyde exposure and to the neurodegeneration in diseases that are associated with increased formaldehyde levels in brain.
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Affiliation(s)
- Ketki Tulpule
- Indian Institute of Science Education and Research, Pashan, Pune, India
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Vijay N, Morris ME. Role of monocarboxylate transporters in drug delivery to the brain. Curr Pharm Des 2013; 20:1487-98. [PMID: 23789956 DOI: 10.2174/13816128113199990462] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/18/2013] [Indexed: 02/08/2023]
Abstract
Monocarboxylate transporters (MCTs) are known to mediate the transport of short chain monocarboxylates such as lactate, pyruvate and butyrate. Currently, fourteen members of this transporter family have been identified by sequence homology, of which only the first four members (MCT1- MCT4) have been shown to mediate the proton-linked transport of monocarboxylates. Another transporter family involved in the transport of endogenous monocarboxylates is the sodium coupled MCTs (SMCTs). These act as a symporter and are dependent on a sodium gradient for their functional activity. MCT1 is the predominant transporter among the MCT isoforms and is present in almost all tissues including kidney, intestine, liver, heart, skeletal muscle and brain. The various isoforms differ in terms of their substrate specificity and tissue localization. Due to the expression of these transporters in the kidney, intestine, and brain, they may play an important role in influencing drug disposition. Apart from endogenous short chain monocarboxylates, they also mediate the transport of exogenous drugs such as salicylic acid, valproic acid, and simvastatin acid. The influence of MCTs on drug pharmacokinetics has been extensively studied for γ-hydroxybutyrate (GHB) including distribution of this drug of abuse into the brain and the results will be summarized in this review. The physiological role of these transporters in the brain and their specific cellular localization within the brain will also be discussed. This review will also focus on utilization of MCTs as potential targets for drug delivery into the brain including their role in the treatment of malignant brain tumors.
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Eid T, Tu N, Lee TSW, Lai JCK. Regulation of astrocyte glutamine synthetase in epilepsy. Neurochem Int 2013; 63:670-81. [PMID: 23791709 DOI: 10.1016/j.neuint.2013.06.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 05/28/2013] [Accepted: 06/08/2013] [Indexed: 11/20/2022]
Abstract
Astrocytes play a crucial role in regulating and maintaining the extracellular chemical milieu of the central nervous system under physiological conditions. Moreover, proliferation of phenotypically altered astrocytes (a.k.a. reactive astrogliosis) has been associated with many neurologic and psychiatric disorders, including mesial temporal lobe epilepsy (MTLE). Glutamine synthetase (GS), which is found in astrocytes, is the only enzyme known to date that is capable of converting glutamate and ammonia to glutamine in the mammalian brain. This reaction is important, because a continuous supply of glutamine is necessary for the synthesis of glutamate and GABA in neurons. The known stoichiometry of glutamate transport across the astrocyte plasma membrane also suggests that rapid metabolism of intracellular glutamate via GS is a prerequisite for efficient glutamate clearance from the extracellular space. Several studies have indicated that the activity of GS in astrocytes is diminished in several brain disorders, including MTLE. It has been hypothesized that the loss of GS activity in MTLE leads to increased extracellular glutamate concentrations and epileptic seizures. Understanding the mechanisms by which GS is regulated may lead to novel therapeutic approaches to MTLE, which is frequently refractory to antiepileptic drugs. This review discusses several known mechanisms by which GS expression and function are influenced, from transcriptional control to enzyme modification.
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Affiliation(s)
- Tore Eid
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, United States.
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Reevaluating Metabolism in Alzheimer's Disease from the Perspective of the Astrocyte-Neuron Lactate Shuttle Model. JOURNAL OF NEURODEGENERATIVE DISEASES 2013; 2013:234572. [PMID: 26316984 PMCID: PMC4437330 DOI: 10.1155/2013/234572] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/02/2013] [Indexed: 01/19/2023]
Abstract
The conventional view of central nervous system (CNS) metabolism is based on the assumption that glucose is the main fuel source for active neurons and is processed in an oxidative manner. However, since the early 1990s research has challenged the idea that the energy needs of nerve cells are met exclusively by glucose and oxidative metabolism. This alternative view of glucose utilization contends that astrocytes metabolize glucose to lactate, which is then released and taken up by nearby neurons and used as a fuel source, commonly known as the astrocyte-neuron lactate shuttle (ANLS) model. Once thought of as a waste metabolite, lactate has emerged as a central player in the maintenance of neuronal function and long-term memory. Decreased neuronal metabolism has traditionally been viewed as a hallmark feature of Alzheimer's disease (AD). However, a more complex picture of CNS metabolism is emerging that may provide valuable insight into the pathophysiological changes that occur during AD and other neurodegenerative diseases. This review will examine the ANLS model and present recent evidence highlighting the critical role that lactate plays in neuronal survival and memory. Moreover, the role of glucose and lactate metabolism in AD will be re-evaluated from the perspective of the ANLS.
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