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Dienel GA, Schousboe A, McKenna MC, Rothman DL. A tribute to Leif Hertz: The historical context of his pioneering studies of the roles of astrocytes in brain energy metabolism, neurotransmission, cognitive functions, and pharmacology identifies important, unresolved topics for future studies. J Neurochem 2024; 168:461-495. [PMID: 36928655 DOI: 10.1111/jnc.15812] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023]
Abstract
Leif Hertz, M.D., D.Sc. (honōris causā) (1930-2018), was one of the original and noteworthy participants in the International Conference on Brain Energy Metabolism (ICBEM) series since its inception in 1993. The biennial ICBEM conferences are organized by neuroscientists interested in energetics and metabolism underlying neural functions; they have had a high impact on conceptual and experimental advances in these fields and on promoting collaborative interactions among neuroscientists. Leif made major contributions to ICBEM discussions and understanding of metabolic and signaling characteristics of astrocytes and their roles in brain function. His studies ranged from uptake of K+ from extracellular fluid and its stimulation of astrocytic respiration, identification, and regulation of enzymes specifically or preferentially expressed in astrocytes in the glutamate-glutamine cycle of excitatory neurotransmission, a requirement for astrocytic glycogenolysis for fueling K+ uptake, involvement of glycogen in memory consolidation in the chick, and pharmacology of astrocytes. This tribute to Leif Hertz highlights his major discoveries, the high impact of his work on astrocyte-neuron interactions, and his unparalleled influence on understanding the cellular basis of brain energy metabolism. His work over six decades has helped integrate the roles of astrocytes into neurotransmission where oxidative and glycogenolytic metabolism during neurotransmitter glutamate turnover are key aspects of astrocytic energetics. Leif recognized that brain astrocytic metabolism is greatly underestimated unless the volume fraction of astrocytes is taken into account. Adjustment for pathway rates expressed per gram tissue for volume fraction indicates that astrocytes have much higher oxidative rates than neurons and astrocytic glycogen concentrations and glycogenolytic rates during sensory stimulation in vivo are similar to those in resting and exercising muscle, respectively. These novel insights are typical of Leif's astute contributions to the energy metabolism field, and his publications have identified unresolved topics that provide the neuroscience community with challenges and opportunities for future research.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA
- Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Mary C McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, 21201, USA
| | - Douglas L Rothman
- Department of Radiology, Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, 06520, USA
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Vaglio-Garro A, Halasz A, Nováková E, Gasser AS, Zavadskis S, Weidinger A, Kozlov AV. Interplay between Energy Supply and Glutamate Toxicity in the Primary Cortical Culture. Biomolecules 2024; 14:543. [PMID: 38785950 PMCID: PMC11118065 DOI: 10.3390/biom14050543] [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: 02/28/2024] [Revised: 04/24/2024] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
Limited substrate availability because of the blood-brain barrier (BBB) has made the brain develop specific molecular mechanisms to survive, using lactate synthesized by astrocytes as a source of energy in neurons. To understand if lactate improves cellular viability and susceptibility to glutamate toxicity, primary cortical cells were incubated in glucose- or lactate-containing media and toxic concentrations of glutamate for 24 h. Cell death was determined by immunostaining and lactate dehydrogenase (LDH) release. Mitochondrial membrane potential and nitric oxide (NO) levels were measured using Tetramethylrhodamine, methyl ester (TMRM) and 4-Amino-5-Methylamino-2',7'-Difluorofluorescein Diacetate (DAF-FM) live staining, respectively. LDH activity was quantified in single cells in the presence of lactate (LDH substrate) and oxamate (LDH inhibitor). Nuclei of cells were stained with DAPI and neurons with MAP2. Based on the distance between neurons and glial cells, they were classified as linked (<10 µm) and non-linked (>10 µm) neurons. Lactate increased cell death rate and the mean value of endogenous NO levels compared to glucose incubations. Mitochondrial membrane potential was lower in the cells cultured with lactate, but this effect was reversed when glutamate was added to the lactate medium. LDH activity was higher in linked neurons compared to non-linked neurons, supporting the hypothesis of the existence of the lactate shuttle between astrocytes and at least a portion of neurons. In conclusion, glucose or lactate can equally preserve primary cortical neurons, but those neurons having a low level of LDH activity and incubated with lactate cannot cover high energetic demand solely with lactate and become more susceptible to glutamate toxicity.
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Affiliation(s)
- Annette Vaglio-Garro
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Andrea Halasz
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
| | - Ema Nováková
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
| | - Andreas Sebastian Gasser
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
| | - Sergejs Zavadskis
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Adelheid Weidinger
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
| | - Andrey V. Kozlov
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, 1200 Vienna, Austria; (A.V.-G.); (A.H.); (E.N.); (A.S.G.); (S.Z.); (A.W.)
- Austrian Cluster for Tissue Regeneration, 1200 Vienna, Austria
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3
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Bhatti MS, Frostig RD. Astrocyte-neuron lactate shuttle plays a pivotal role in sensory-based neuroprotection in a rat model of permanent middle cerebral artery occlusion. Sci Rep 2023; 13:12799. [PMID: 37550353 PMCID: PMC10406860 DOI: 10.1038/s41598-023-39574-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/27/2023] [Indexed: 08/09/2023] Open
Abstract
We have previously demonstrated protection from impending cortical ischemic stroke is achievable by sensory stimulation of the ischemic area in an adult rat model of permanent middle cerebral artery occlusion (pMCAo). We have further demonstrated that a major underpinning mechanism that is necessary for such protection is the system of collaterals among cerebral arteries that results in reperfusion of the MCA ischemic territory. However, since such collateral flow is weak, it may be necessary but not sufficient for protection and therefore we sought other complementary mechanisms that contribute to sensory-based protection. We hypothesized that astrocytes-neuron lactate shuttle (ANLS) activation could be another potential underpinning mechanism that complements collateral flow in the protection process. Supporting our hypothesis, using functional imaging, pharmacological treatments, and postmortem histology, we showed that ANLS played a pivotal role in sensory stimulation-based protection of cortex and therefore serves as the other supporting mechanism underpinning the protection process.
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Affiliation(s)
- Mehwish S Bhatti
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, Irvine, CA, USA.
| | - Ron D Frostig
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, Irvine, CA, USA.
- Department of Biomedical Engineering, School of Engineering, University of California, Irvine, Irvine, CA, USA.
- Center for Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, USA.
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4
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Bhatti M, Frostig RD. Astrocyte-neuron lactate shuttle plays a pivotal role in sensory-based neuroprotection in a rat model of permanent middle cerebral artery occlusion. RESEARCH SQUARE 2023:rs.3.rs-2698138. [PMID: 37034797 PMCID: PMC10081351 DOI: 10.21203/rs.3.rs-2698138/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
We have previously demonstrated protection from impending cortical stroke is achievable by sensory stimulation of the ischemic area in an adult rat model of permanent middle cerebral artery occlusion (pMCAo). We have further demonstrated that a major underpinning mechanism that is necessary for such protection is the system of collaterals among cerebral arteries that results in reperfusion of the MCA ischemic territory. However, since such collateral flow is weak, it may be necessary but not sufficient for protection and therefore we were seeking other complementary mechanisms that contribute to sensory-based protection. We hypothesized that astrocytes-to-neuron shuttle (ANLS) is another potential underpinning mechanism that could complement collateral flow in the protection process. Supporting our hypothesis, using functional imaging, pharmacological treatments, and postmortem histology, we show that ANLS has a pivotal role in sensory-based protection of cortex and therefor serves as the other supporting mechanism underpinning the protection process.
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5
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Yassine HN, Self W, Kerman BE, Santoni G, Navalpur Shanmugam N, Abdullah L, Golden LR, Fonteh AN, Harrington MG, Gräff J, Gibson GE, Kalaria R, Luchsinger JA, Feldman HH, Swerdlow RH, Johnson LA, Albensi BC, Zlokovic BV, Tanzi R, Cunnane S, Samieri C, Scarmeas N, Bowman GL. Nutritional metabolism and cerebral bioenergetics in Alzheimer's disease and related dementias. Alzheimers Dement 2023; 19:1041-1066. [PMID: 36479795 PMCID: PMC10576546 DOI: 10.1002/alz.12845] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/12/2022] [Accepted: 10/05/2022] [Indexed: 12/13/2022]
Abstract
Disturbances in the brain's capacity to meet its energy demand increase the risk of synaptic loss, neurodegeneration, and cognitive decline. Nutritional and metabolic interventions that target metabolic pathways combined with diagnostics to identify deficits in cerebral bioenergetics may therefore offer novel therapeutic potential for Alzheimer's disease (AD) prevention and management. Many diet-derived natural bioactive components can govern cellular energy metabolism but their effects on brain aging are not clear. This review examines how nutritional metabolism can regulate brain bioenergetics and mitigate AD risk. We focus on leading mechanisms of cerebral bioenergetic breakdown in the aging brain at the cellular level, as well as the putative causes and consequences of disturbed bioenergetics, particularly at the blood-brain barrier with implications for nutrient brain delivery and nutritional interventions. Novel therapeutic nutrition approaches including diet patterns are provided, integrating studies of the gut microbiome, neuroimaging, and other biomarkers to guide future personalized nutritional interventions.
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Affiliation(s)
- Hussein N Yassine
- Department of Medicine, Keck School of Medicine, University of Southern, California, Los Angeles, California, USA
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Wade Self
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Bilal E Kerman
- Department of Medicine, Keck School of Medicine, University of Southern, California, Los Angeles, California, USA
| | - Giulia Santoni
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
| | - NandaKumar Navalpur Shanmugam
- Department of Neurology, Genetics and Aging Research Unit, McCance Center for Brain Health, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Lesley R Golden
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Alfred N Fonteh
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Huntington Medical Research Institutes, Pasadena, California, USA
| | - Michael G Harrington
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Johannes Gräff
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
| | - Gary E Gibson
- Brain and Mind Research Institute, Weill Cornell Medicine, Burke Neurological Institute, White Plains, New York, USA
| | - Raj Kalaria
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Jose A Luchsinger
- Department of Medicine and Epidemiology, Columbia University Irving Medical Center, New York City, New York, USA
| | - Howard H Feldman
- Department of Neurosciences, University of California, San Diego, California, USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas School of Medicine, Kansas City, Kansas, USA
| | - Lance A Johnson
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Benedict C Albensi
- Nova Southeastern Univ. College of Pharmacy, Davie, Florida, USA
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Berislav V Zlokovic
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Rudolph Tanzi
- Department of Neurology, Genetics and Aging Research Unit, McCance Center for Brain Health, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Stephen Cunnane
- Department of Medicine, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Cécilia Samieri
- Univ. Bordeaux, INSERM, BPH, U1219, F-33000, Bordeaux, France
| | - Nikolaos Scarmeas
- 1st Department of Neurology, Aiginition Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece
- Department of Neurology, Columbia University, New York City, New York, USA
| | - Gene L Bowman
- Department of Neurology, Genetics and Aging Research Unit, McCance Center for Brain Health, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, USA
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6
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The Effects of Prenatal Dexamethasone Exposure on Brain Metabolic Homeostasis in Adulthood: Implications for Depression. Int J Mol Sci 2023; 24:ijms24021156. [PMID: 36674678 PMCID: PMC9866429 DOI: 10.3390/ijms24021156] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/09/2022] [Accepted: 12/29/2022] [Indexed: 01/10/2023] Open
Abstract
Since depression produces a long-term negative impact on quality of life, understanding the pathophysiological changes implicated in this disorder is urgent. There is growing evidence that demonstrates a key role for dysfunctional energy metabolism in driving the onset of depression; thus, bioenergetic alterations should be extensively studied. Brain metabolism is known to be a glucocorticoid-sensitive process, but the long-lasting consequences in adulthood following high levels of glucocorticoids at the early stages of life are unclear. We examined a possible association between brain energetic changes induced by synthetic glucocorticoid-dexamethasone treatment in the prenatal period and depressive-like behavior. The results show a reduction in the oxidative phosphorylation process, Krebs cycle impairment, and a weakening of the connection between the Krebs cycle and glycolysis in the frontal cortex of animals receiving dexamethasone, which leads to ATP reduction. These changes appear to be mainly due to decreased expression of pyruvate dehydrogenase, impairment of lactate transport to neurons, and pyruvate to the mitochondria. Acute stress in adulthood only slightly modified the observed alterations in the frontal cortex, while in the case of the hippocampus, prenatal exposure to dexamethasone made this structure more sensitive to future adverse factors.
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7
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Schurr A. From rags to riches: Lactate ascension as a pivotal metabolite in neuroenergetics. Front Neurosci 2023; 17:1145358. [PMID: 36937681 PMCID: PMC10019773 DOI: 10.3389/fnins.2023.1145358] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
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8
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Cruz E, Bessières B, Magistretti P, Alberini CM. Differential role of neuronal glucose and PFKFB3 in memory formation during development. Glia 2022; 70:2207-2231. [PMID: 35916383 PMCID: PMC9474594 DOI: 10.1002/glia.24248] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/21/2022] [Accepted: 07/05/2022] [Indexed: 11/06/2022]
Abstract
The consumption of glucose in the brain peaks during late childhood; yet, whether and how glucose metabolism is differentially regulated in the brain during childhood compared to adulthood remains to be understood. In particular, it remains to be determined how glucose metabolism is involved in behavioral activations such as learning. Here we show that, compared to adult, the juvenile rat hippocampus has significantly higher mRNA levels of several glucose metabolism enzymes belonging to all glucose metabolism pathways, as well as higher levels of the monocarboxylate transporters MCT1 and MCT4 and the glucose transporters endothelial-GLUT1 and GLUT3 proteins. Furthermore, relative to adults, long-term episodic memory formation in juvenile animals requires significantly higher rates of aerobic glycolysis and astrocytic-neuronal lactate coupling in the hippocampus. Only juvenile but not adult long-term memory formation recruits GLUT3, neuronal 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and more efficiently engages glucose in the hippocampus. Hence, compared to adult, the juvenile hippocampus distinctively regulates glucose metabolism pathways, and formation of long-term memory in juveniles involves differential neuronal glucose metabolism mechanisms.
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Affiliation(s)
- Emmanuel Cruz
- 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
| | - Pierre Magistretti
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Cristina M. Alberini
- Center for Neural Science, New York University, New York, New York 10003
- Lead contact: Cristina M. Alberini
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9
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Głombik K, Detka J, Budziszewska B. Hormonal Regulation of Oxidative Phosphorylation in the Brain in Health and Disease. Cells 2021; 10:2937. [PMID: 34831160 PMCID: PMC8616269 DOI: 10.3390/cells10112937] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/18/2022] Open
Abstract
The developing and adult brain is a target organ for the vast majority of hormones produced by the body, which are able to cross the blood-brain barrier and bind to their specific receptors on neurons and glial cells. Hormones ensure proper communication between the brain and the body by activating adaptive mechanisms necessary to withstand and react to changes in internal and external conditions by regulating neuronal and synaptic plasticity, neurogenesis and metabolic activity of the brain. The influence of hormones on energy metabolism and mitochondrial function in the brain has gained much attention since mitochondrial dysfunctions are observed in many different pathological conditions of the central nervous system. Moreover, excess or deficiency of hormones is associated with cell damage and loss of function in mitochondria. This review aims to expound on the impact of hormones (GLP-1, insulin, thyroid hormones, glucocorticoids) on metabolic processes in the brain with special emphasis on oxidative phosphorylation dysregulation, which may contribute to the formation of pathological changes. Since the brain concentrations of sex hormones and neurosteroids decrease with age as well as in neurodegenerative diseases, in parallel with the occurrence of mitochondrial dysfunction and the weakening of cognitive functions, their beneficial effects on oxidative phosphorylation and expression of antioxidant enzymes are also discussed.
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Affiliation(s)
- Katarzyna Głombik
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
| | - Jan Detka
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
| | - Bogusława Budziszewska
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
- Department of Biochemical Toxicology, Chair of Toxicology, Medical College, Jagiellonian University, Medyczna 9, 30-688 Kraków, Poland
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10
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Lee S, Kim TD, Kim RY, Joo Y, Chung YA, Lim SM, Lyoo IK, Kim J, Yoon S. Hippocampal subregional alterations and verbal fluency in the early stage of type 2 diabetes mellitus. Eur J Neurosci 2021; 54:7550-7559. [PMID: 34687097 DOI: 10.1111/ejn.15505] [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: 04/15/2021] [Revised: 10/16/2021] [Accepted: 10/21/2021] [Indexed: 11/30/2022]
Abstract
Growing evidence indicates that type 2 diabetes mellitus (T2DM)-related cognitive dysfunction may develop in the early stage of the disease and is often accompanied by hippocampal structural alterations. In the current study, we investigated volume and shape alterations of the hippocampus at a subregional level in patients with T2DM. With the use of high-resolution brain structural images that were obtained from 30 T2DM patients with less than 5 years of disease duration and 30 healthy individuals, volumetric and shape analyses were performed. We also assessed the relationship between T2DM-related hippocampal structural alterations and performance on verbal fluency. In volumetric analysis, total hippocampal volume was smaller in the T2DM group, relative to the control group. At a subregional level, T2DM patients showed significant inward deformation and volume reduction of the right dentate gyrus and cornu ammonis 2/3 subregions as compared with healthy individuals. In particular, T2DM patients with lower performance on verbal fluency had smaller right dentate gyrus volumes relative to those with higher performance. These findings suggest that the hippocampus may undergo atrophy at a subregional level even in the early stage of T2DM, and this subregion-specific atrophy may be associated with reduced performance on verbal fluency.
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Affiliation(s)
- Suji Lee
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
| | - Tammy D Kim
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea
| | - Rye Young Kim
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea.,Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, South Korea
| | - Yoonji Joo
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea.,Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, South Korea
| | - Yong-An Chung
- Department of Radiology, Incheon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Incheon, South Korea
| | - Soo Mee Lim
- Department of Radiology, College of Medicine, Ewha Womans University, Seoul, South Korea
| | - In Kyoon Lyoo
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea.,Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea.,The Brain Institute and Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA
| | - Jungyoon Kim
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Sujung Yoon
- Ewha Brain Institute, Ewha Womans University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
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11
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Głombik K, Detka J, Budziszewska B. Venlafaxine and L-Thyroxine Treatment Combination: Impact on Metabolic and Synaptic Plasticity Changes in an Animal Model of Coexisting Depression and Hypothyroidism. Cells 2021; 10:cells10061394. [PMID: 34198731 PMCID: PMC8227539 DOI: 10.3390/cells10061394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/23/2022] Open
Abstract
The clinical effectiveness of supportive therapy with thyroid hormones in drug-resistant depression is well-known; however, the mechanisms of action of these hormones in the adult brain have not been fully elucidated to date. We determined the effects of venlafaxine and/or L-thyroxine on metabolic parameters and markers involved in the regulation of synaptic plasticity and cell damage in an animal model of coexisting depression and hypothyroidism, namely, Wistar Kyoto rats treated with propylthiouracil. In this model, in relation to the depression model itself, the glycolysis process in the brain was weakened, and a reduction in pyruvate dehydrogenase in the frontal cortex was normalized only by the combined treatment with L-thyroxine and venlafaxine, whereas changes in pyruvate and lactate levels were affected by all applied therapies. None of the drugs improved the decrease in the expression of mitochondrial respiratory chain enzymes. No intensification of glucocorticoid action was shown, while an unfavorable change caused by the lack of thyroid hormones was an increase in the caspase-1 level, which was not reversed by venlafaxine alone. The results indicated that the combined administration of drugs was more effective in normalizing glycolysis and the transition to the Krebs cycle than the use of venlafaxine or L-thyroxine alone.
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Affiliation(s)
- Katarzyna Głombik
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
- Correspondence: ; Tel.: +48-12-662-33-94
| | - Jan Detka
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
| | - Bogusława Budziszewska
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
- Department of Biochemical Toxicology, Medical College, Jagiellonian University, Medyczna 9, 30-688 Kraków, Poland
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12
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Głombik K, Budziszewska B, Basta-Kaim A. Mitochondria-targeting therapeutic strategies in the treatment of depression. Mitochondrion 2021; 58:169-178. [PMID: 33766747 DOI: 10.1016/j.mito.2021.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 02/26/2021] [Accepted: 03/17/2021] [Indexed: 12/12/2022]
Abstract
Depression is an affective disease with a complex clinical picture that is characterized by mood and emotional disturbances. It is known that several factors contribute to the risk of developing depression. The concept that mitochondrial dysfunction is one of the causes of depression is supported by a wide range of studies on cell cultures, animal models, and clinical research. An understanding the relationship between mitochondrial processes and central nervous system abnormalities that occur in the course of depression can guide the development of novel mitochondrial targeted therapeutic strategies as well as the usage of currently available antidepressants in a new context. This brief review aims to summarize recent findings on mitochondria dysfunction in depression, provide insight into therapeutic strategies targeting mitochondrial pathways, allude to future promising therapies, and discuss factors that can be used to improve treatment outcomes. The main focus is on new aspects (the effects of nutraceuticals and physical activity on brain metabolism), which can be combined with the available treatment options [monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs) and atypical drugs] to enhance their therapeutic effects.
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Affiliation(s)
- Katarzyna Głombik
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Kraków 31-343, Poland.
| | - Bogusława Budziszewska
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Kraków 31-343, Poland
| | - Agnieszka Basta-Kaim
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, Kraków 31-343, Poland
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13
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Pires Monteiro S, Voogd E, Muzzi L, De Vecchis G, Mossink B, Levers M, Hassink G, Van Putten M, Le Feber J, Hofmeijer J, Frega M. Neuroprotective effect of hypoxic preconditioning and neuronal activation in a in vitro human model of the ischemic penumbra. J Neural Eng 2021; 18:036016. [PMID: 33724235 DOI: 10.1088/1741-2552/abe68a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE In ischemic stroke, treatments to protect neurons from irreversible damage are urgently needed. Studies in animal models have shown that neuroprotective treatments targeting neuronal silencing improve brain recovery, but in clinical trials none of these were effective in patients. This failure of translation poses doubts on the real efficacy of treatments tested and on the validity of animal models for human stroke. Here, we established a human neuronal model of the ischemic penumbra by using human induced pluripotent stem cells and we provided an in-depth characterization of neuronal responses to hypoxia and treatment strategies at the network level. APPROACH We generated neurons from induced pluripotent stem cells derived from healthy donor and we cultured them on micro-electrode arrays. We measured the electrophysiological activity of human neuronal networks under controlled hypoxic conditions. We tested the effect of different treatment strategies on neuronal network functionality. MAIN RESULTS Human neuronal networks are vulnerable to hypoxia reflected by a decrease in activity and synchronicity under low oxygen conditions. We observe that full, partial or absent recovery depend on the timing of re-oxygenation and we provide a critical time threshold that, if crossed, is associated with irreversible impairments. We found that hypoxic preconditioning improves resistance to a second hypoxic insult. Finally, in contrast to previously tested, ineffective treatments, we show that stimulatory treatments counteracting neuronal silencing during hypoxia, such as optogenetic stimulation, are neuroprotective. SIGNIFICANCE We presented a human neuronal model of the ischemic penumbra and we provided insights that may offer the basis for novel therapeutic approaches for patients after stroke. The use of human neurons might improve drug discovery and translation of findings to patients and might open new perspectives for personalized investigations.
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Affiliation(s)
- Sara Pires Monteiro
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands
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14
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Glucose transporters in brain in health and disease. Pflugers Arch 2020; 472:1299-1343. [PMID: 32789766 PMCID: PMC7462931 DOI: 10.1007/s00424-020-02441-x] [Citation(s) in RCA: 219] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/15/2022]
Abstract
Energy demand of neurons in brain that is covered by glucose supply from the blood is ensured by glucose transporters in capillaries and brain cells. In brain, the facilitative diffusion glucose transporters GLUT1-6 and GLUT8, and the Na+-d-glucose cotransporters SGLT1 are expressed. The glucose transporters mediate uptake of d-glucose across the blood-brain barrier and delivery of d-glucose to astrocytes and neurons. They are critically involved in regulatory adaptations to varying energy demands in response to differing neuronal activities and glucose supply. In this review, a comprehensive overview about verified and proposed roles of cerebral glucose transporters during health and diseases is presented. Our current knowledge is mainly based on experiments performed in rodents. First, the functional properties of human glucose transporters expressed in brain and their cerebral locations are described. Thereafter, proposed physiological functions of GLUT1, GLUT2, GLUT3, GLUT4, and SGLT1 for energy supply to neurons, glucose sensing, central regulation of glucohomeostasis, and feeding behavior are compiled, and their roles in learning and memory formation are discussed. In addition, diseases are described in which functional changes of cerebral glucose transporters are relevant. These are GLUT1 deficiency syndrome (GLUT1-SD), diabetes mellitus, Alzheimer’s disease (AD), stroke, and traumatic brain injury (TBI). GLUT1-SD is caused by defect mutations in GLUT1. Diabetes and AD are associated with changed expression of glucose transporters in brain, and transporter-related energy deficiency of neurons may contribute to pathogenesis of AD. Stroke and TBI are associated with changes of glucose transporter expression that influence clinical outcome.
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15
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Byman E, Schultz N, Blom AM, Wennström M. A Potential Role for α-Amylase in Amyloid-β-Induced Astrocytic Glycogenolysis and Activation. J Alzheimers Dis 2020; 68:205-217. [PMID: 30775997 DOI: 10.3233/jad-180997] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Astrocytes produce and store the energy reserve glycogen. However, abnormal large glycogen units accumulate if the production or degradation of glycogen is disturbed, a finding often seen in patients with Alzheimer's disease (AD). We have shown increased activity of glycogen degrading α-amylase in AD patients and α-amylase positive glial cells adjacent to AD characteristic amyloid-β (Aβ) plaques. OBJECTIVES Investigate the role of α-amylase in astrocytic glycogenolysis in presence of Aβ. METHODS Presence of α-amylase and large glycogen units in postmortem entorhinal cortex from AD patients and non-demented controls were analyzed by immunohistological stainings. Impact of different Aβ42 aggregation forms on enzymatic activity (α-amylase, pyruvate kinase, and lactate dehydrogenase), lactate secretion, and accumulation of large glycogen units in cultured astrocytes were analyzed by activity assays, ELISA, and immunocytochemistry, respectively. RESULTS AD patients showed increased number of α-amylase positive glial cells. The glial cells co-expressed the astrocytic marker glial fibrillary acidic protein, displayed hypertrophic features, and increased amount of large glycogen units. We further found increased load of large glycogen units, α-amylase immunoreactivity and α-amylase activity in cultured astrocytes stimulated with fibril Aβ42, with increased pyruvate kinase activity, but unaltered lactate release as downstream events. The fibril Aβ42-induced α-amylase activity was attenuated by β-adrenergic receptor antagonist propranolol. DISCUSSION We hypothesize that astrocytes respond to fibril Aβ42 in Aβ plaques by increasing their α-amylase production to either liberate energy or regulate functions needed in reactive processes. These findings indicate α-amylase as an important actor involved in AD associated neuroinflammation.
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Affiliation(s)
- Elin Byman
- Department of Clinical Sciences Malmö, Clinical Memory Research Unit, Lund University, Malmö, Sweden
| | - Nina Schultz
- Department of Clinical Sciences Malmö, Clinical Memory Research Unit, Lund University, Malmö, Sweden
| | | | - Anna M Blom
- Department of Translational Medicine, Division of Medical Protein Chemistry, Lund University, Malmö, Sweden
| | - Malin Wennström
- Department of Clinical Sciences Malmö, Clinical Memory Research Unit, Lund University, Malmö, Sweden
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16
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Roosterman D, Cottrell GS. Astrocytes and neurons communicate via a monocarboxylic acid shuttle. AIMS Neurosci 2020; 7:94-106. [PMID: 32607414 PMCID: PMC7321766 DOI: 10.3934/neuroscience.2020007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023] Open
Abstract
Since formulation of the Astrocyte-Neuron Lactate Shuttle (ANLS) hypothesis in 1994, the hypothesis has provoked criticism and debate. Our review does not criticise, but rather integrates experimental data characterizing proton-linked monocarboxylate transporters (MCTs) into the ANLS. MCTs have wide substrate specificity and are discussed to be in protein complex with a proton donor (PD). We particularly focus on the proton-driven transfer of l-lactic acid (l-lacH) and pyruvic acid (pyrH), were PDs link MCTs to a flow of energy. The precise nature of the PD predicts the activity and catalytic direction of MCTs. By doing so, we postulate that the MCT4·phosphoglycerate kinase complex exports and at the same time in the same astrocyte, MCT1·carbonic anhydrase II complex imports monocarboxylic acids. Similarly, neuronal MCT2 preferentially imports pyrH. The repertoire of MCTs in astrocytes and neurons allows them to communicate via monocarboxylic acids. A change in imported pyrH/l-lacH ratio in favour of l-lacH encodes signals stabilizing the transit of glucose from astrocytes to neurons. The presented astrocyte neuron communication hypothesis has the potential to unite the community by suggesting that the exchange of monocarboxylic acids paves the path of glucose provision.
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Affiliation(s)
- Dirk Roosterman
- Ruhr Universität Bochum, LWL-Hospital of Psychiatry, Bochum, Germany
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17
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Fujiwara A, Nakao K, Ueno T, Matsumura S, Ito S, Minami T. Stiripentol alleviates neuropathic pain in L5 spinal nerve-transected mice. J Anesth 2020; 34:373-381. [PMID: 32189128 DOI: 10.1007/s00540-020-02762-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/07/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE Antiepileptic drugs are used not only for the treatment of epilepsy but also for that of neuropathic pain. However, their action mechanisms have not always been well explained. Stiripentol, an effective antiepileptic drug indicated as a therapeutic for Dravet syndrome, was recently shown to act as an inhibitor of lactate dehydrogenase in astrocytes. In this present study, we examined the effect of stiripentol on neuropathic pain in L5 spinal nerve-transected mice. METHODS We carried out behavioral tests using calibrated von Frey filaments and the immunohistochemistry of glial fibrillary acidic protein, an astrocyte marker, in L5 spinal nerve-transected mice after intrathecal administration of drugs. RESULTS Like other anticonvulsants such as gabapentin and carbamazepine, stiripentol alleviated mechanical hyperalgesia induced by L5 spinal nerve transection in a dose-dependent manner, when intrathecally administered to mice 7, 14, and 28 days after L5 spinal nerve transection. Likewise, α-cyano-4-hydroxycinnamic acid, a broad inhibitor of monocarboxylate transporters, diminished mechanical hyperalgesia induced by L5 spinal nerve transection. Simultaneous administration of L-lactate negated the analgesic effect elicited by stiripentol, carbamazepine or α-cyano-4-hydroxycinnamic acid, but not that by gabapentin. None of the anticonvulsants affected the immunoreactivity of glial fibrillary acidic protein. CONCLUSIONS This present study demonstrated that stiripentol was effective against neuropathic pain and suggested that the astrocyte-neuron lactate shuttle was involved in such pain.
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Affiliation(s)
- Atsushi Fujiwara
- Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, 569-8686, Japan
| | - Kenta Nakao
- Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, 569-8686, Japan
| | - Takeshi Ueno
- Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, 569-8686, Japan
| | - Shinji Matsumura
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Seiji Ito
- Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, 569-8686, Japan
| | - Toshiaki Minami
- Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, 569-8686, Japan.
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18
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Girish KS, Katkar GD, Harrison RA, Kemparaju K. Research into the Causes of Venom-Induced Mortality and Morbidity Identifies New Therapeutic Opportunities. Am J Trop Med Hyg 2020; 100:1043-1048. [PMID: 30675839 PMCID: PMC6493937 DOI: 10.4269/ajtmh.17-0877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Snakebite primarily affects rural subsistent farming populations in underdeveloped and developing nations. The annual number of deaths (100,000) and physical disabilities (400,000) of snakebite victims is a societal tragedy that poses a significant added socioeconomic burden to the society. Antivenom therapy is the treatment of choice for snakebite but, as testified by the continuing high rates of mortality and morbidity, too many rural tropical snakebite victims fail to access effective treatment. Here, we advocate for more basic research to better understand the pathogenesis of systemic and local envenoming and describe how research outcomes can identify novel snakebite therapeutic strategies with the potential to be more accessible and affordable to victims than current treatment.
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Affiliation(s)
- Kesturu S Girish
- Department of Studies and Research in Biochemistry, Tumkur University, Tumakuru, India.,Department of Studies in Biochemistry, University of Mysore, Mysuru, India
| | - Gajanan D Katkar
- Cardiovascular Research Lab, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Studies in Biochemistry, University of Mysore, Mysuru, India
| | - Robert A Harrison
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kempaiah Kemparaju
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
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19
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Abstract
Both intense physical activity and potent psychosocial stressors increase blood lactate. Raising lactate levels by infusing the chemical can have an anxiogenic effect. Here, we compare the relationship between changes in lactate and anxiety levels resulting from two standardized stressors. We investigated the effects of the Multiple Wingate All-Out Performance Test (WG), a strong physical stressor, and the Trier Social Stress Test (TSST), a well-documented psychosocial stressor, in 32 healthy young men using a crossover design. Before and after each stressor, venous blood was analyzed for lactate levels and the State-Trait-Anxiety Inventory (STAI) was given. Both stressors raised both lactate and anxiety significantly above their baseline levels. While the rise in lactate was much higher for the WG than for the TSST, the rises in anxiety were nearly equal. Individual fitness did not influence the results for lactate or anxiety. No significant relation between lactate and anxiety changes were found. Thus, our results as well as the literature suggest that lactate is an important variable for understanding the impact of sport participation.
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Affiliation(s)
- Robin Hermann
- Institute of Preventive Research, German Sport University Cologne , Cologne , Germany
- Clinic and Policlinic for Psychosomatic Medicine and Psychotherapy, University Medicine Mainz , Mainz , Germany
| | - Daniel Lay
- Department of Preventative and Rehabilitative Sports and Performance Medicine, Institute of Cardiology and Sports Medicine, German Sport University Cologne , Cologne , Germany
| | - Patrick Wahl
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiology and Sports Medicine, German Sport University Cologne , Cologne , Germany
| | - Walton T Roth
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine , Stanford , CA , USA
| | - Katja Petrowski
- Clinic and Policlinic for Psychosomatic Medicine and Psychotherapy, University Medicine Mainz , Mainz , Germany
- Klinik und Poliklinik für Psychotherapie und Psychosomatik, Technische Universität Dresden , Dresden , Germany
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20
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Zahra K, Gopal N, Freeman WD, Turnbull MT. Using Cerebral Metabolites to Guide Precision Medicine for Subarachnoid Hemorrhage: Lactate and Pyruvate. Metabolites 2019; 9:metabo9110245. [PMID: 31652842 PMCID: PMC6918279 DOI: 10.3390/metabo9110245] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/09/2019] [Accepted: 10/22/2019] [Indexed: 12/20/2022] Open
Abstract
Subarachnoid hemorrhage (SAH) is one of the deadliest types of strokes with high rates of morbidity and permanent injury. Fluctuations in the levels of cerebral metabolites following SAH can be indicators of brain injury severity. Specifically, the changes in the levels of key metabolites involved in cellular metabolism, lactate and pyruvate, can be used as a biomarker for patient prognosis and tailor treatment to an individual’s needs. Here, clinical research is reviewed on the usefulness of cerebral lactate and pyruvate measurements as a predictive tool for SAH outcomes and their potential to guide a precision medicine approach to treatment.
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Affiliation(s)
- Kaneez Zahra
- Department of Neurology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
| | - Neethu Gopal
- Department of Neurology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
| | - William D Freeman
- Department of Neurology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
- Department of Neurologic Surgery, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
- Department of Critical Care Medicine, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
| | - Marion T Turnbull
- Department of Neurology, Mayo Clinic, 4500 San Pablo Rd, Jacksonville, FL 32224, USA.
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21
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Capo Rangel G, Prezioso J, Gerardo-Giorda L, Somersalo E, Calvetti D. Brain energetics plays a key role in the coordination of electrophysiology, metabolism and hemodynamics: Evidence from an integrated computational model. J Theor Biol 2019; 478:26-39. [DOI: 10.1016/j.jtbi.2019.06.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 10/26/2022]
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22
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Abbink MR, van Deijk ALF, Heine VM, Verheijen MH, Korosi A. The involvement of astrocytes in early-life adversity induced programming of the brain. Glia 2019; 67:1637-1653. [PMID: 31038797 PMCID: PMC6767561 DOI: 10.1002/glia.23625] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 12/13/2022]
Abstract
Early‐life adversity (ELA) in the form of stress, inflammation, or malnutrition, can increase the risk of developing psychopathology or cognitive problems in adulthood. The neurobiological substrates underlying this process remain unclear. While neuronal dysfunction and microglial contribution have been studied in this context, only recently the role of astrocytes in early‐life programming of the brain has been appreciated. Astrocytes serve many basic roles for brain functioning (e.g., synaptogenesis, glutamate recycling), and are unique in their capacity of sensing and integrating environmental signals, as they are the first cells to encounter signals from the blood, including hormonal changes (e.g., glucocorticoids), immune signals, and nutritional information. Integration of these signals is especially important during early development, and therefore we propose that astrocytes contribute to ELA induced changes in the brain by sensing and integrating environmental signals and by modulating neuronal development and function. Studies in rodents have already shown that ELA can impact astrocytes on the short and long term, however, a critical review of these results is currently lacking. Here, we will discuss the developmental trajectory of astrocytes, their ability to integrate stress, immune, and nutritional signals from the early environment, and we will review how different types of early adversity impact astrocytes.
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Affiliation(s)
- Maralinde R Abbink
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Anne-Lieke F van Deijk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit, Amsterdam, The Netherlands
| | - Vivi M Heine
- Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit, Amsterdam, The Netherlands
| | - Mark H Verheijen
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit, Amsterdam, The Netherlands
| | - Aniko Korosi
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
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Schurr A. Glycolysis Paradigm Shift Dictates a Reevaluation of Glucose and Oxygen Metabolic Rates of Activated Neural Tissue. Front Neurosci 2018; 12:700. [PMID: 30364172 PMCID: PMC6192285 DOI: 10.3389/fnins.2018.00700] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/18/2018] [Indexed: 01/31/2023] Open
Abstract
In 1988 two seminal studies were published, both instigating controversy. One concluded that “the energy needs of activated neural tissue are minimal, being fulfilled via the glycolytic pathway alone,” a conclusion based on the observation that neural activation increased glucose consumption, which was not accompanied by a corresponding increase in oxygen consumption (Fox et al., 1988). The second demonstrated that neural tissue function can be supported exclusively by lactate as the energy substrate (Schurr et al., 1988). While both studies continue to have their supporters and detractors, the present review attempts to clarify the issues responsible for the persistence of the controversies they have provoked and offer a possible rationalization. The concept that lactate rather than pyruvate, is the glycolytic end-product, both aerobically and anaerobically, and thus the real mitochondrial oxidative substrate, has gained a greater acceptance over the years. The idea of glycolysis as the sole ATP supplier for neural activation (glucose → lactate + 2ATP) continues to be controversial. Lactate oxidative utilization by activated neural tissue could explain the mismatch between glucose and oxygen consumption and resolve the existing disagreements among users of imaging methods to measure the metabolic rates of the two energy metabolic substrates. The postulate that the energy necessary for active neural tissue is supplied by glycolysis alone stems from the original aerobic glycolysis paradigm. Accordingly, glucose consumption is accompanied by oxygen consumption at 1–6 ratio. Since Fox et al. (1988) observed only a minimal if non-existent oxygen consumption compared to glucose consumption, their conclusion make sense. Nevertheless, considering (a) the shift in the paradigm of glycolysis (glucose → lactate; lactate + O2 + mitochondria → pyruvate → TCA cycle → CO2 + H2O + 17ATP); (b) that one mole of lactate oxidation requires only 50% of the amount of oxygen necessary for the oxidation of one mole of glucose; and (c) that lactate, as a mitochondrial substrate, is over eight times more efficient at ATP production than glucose as a glycolytic substrate, suggest that future studies of cerebral metabolic rates of activated neural tissue should include along with the measurements of CMRO2 and CMRglucose the measurement of CMRlactate.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Louisville, Louisville, KY, United States
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24
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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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Liu B, Teschemacher AG, Kasparov S. Astroglia as a cellular target for neuroprotection and treatment of neuro-psychiatric disorders. Glia 2017; 65:1205-1226. [PMID: 28300322 PMCID: PMC5669250 DOI: 10.1002/glia.23136] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 12/12/2022]
Abstract
Astrocytes are key homeostatic cells of the central nervous system. They cooperate with neurons at several levels, including ion and water homeostasis, chemical signal transmission, blood flow regulation, immune and oxidative stress defense, supply of metabolites and neurogenesis. Astroglia is also important for viability and maturation of stem-cell derived neurons. Neurons critically depend on intrinsic protective and supportive properties of astrocytes. Conversely, all forms of pathogenic stimuli which disturb astrocytic functions compromise neuronal functionality and viability. Support of neuroprotective functions of astrocytes is thus an important strategy for enhancing neuronal survival and improving outcomes in disease states. In this review, we first briefly examine how astrocytic dysfunction contributes to major neurological disorders, which are traditionally associated with malfunctioning of processes residing in neurons. Possible molecular entities within astrocytes that could underpin the cause, initiation and/or progression of various disorders are outlined. In the second section, we explore opportunities enhancing neuroprotective function of astroglia. We consider targeting astrocyte-specific molecular pathways which are involved in neuroprotection or could be expected to have a therapeutic value. Examples of those are oxidative stress defense mechanisms, glutamate uptake, purinergic signaling, water and ion homeostasis, connexin gap junctions, neurotrophic factors and the Nrf2-ARE pathway. We propose that enhancing the neuroprotective capacity of astrocytes is a viable strategy for improving brain resilience and developing new therapeutic approaches.
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Affiliation(s)
- Beihui Liu
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Anja G. Teschemacher
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
| | - Sergey Kasparov
- School of Physiology, Pharmacology and NeuroscienceUniversity of Bristol, University WalkBS8 1TDUnited Kingdom
- Institute for Chemistry and BiologyBaltic Federal UniversityKaliningradRussian Federation
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26
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Waitt AE, Reed L, Ransom BR, Brown AM. Emerging Roles for Glycogen in the CNS. Front Mol Neurosci 2017; 10:73. [PMID: 28360839 PMCID: PMC5352909 DOI: 10.3389/fnmol.2017.00073] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/03/2017] [Indexed: 11/20/2022] Open
Abstract
The ability of glycogen, the depot into which excess glucose is stored in mammals, to act as a source of rapidly available energy substrate, has been exploited by several organs for both general and local advantage. The liver, expressing the highest concentration of glycogen maintains systemic normoglycemia ensuring the brain receives a supply of glucose in excess of demand. However the brain also contains glycogen, although its role is more specialized. Brain glycogen is located exclusively in astrocytes in the adult, with the exception of pathological conditions, thus in order to benefit neurons, and energy conduit (lactate) is trafficked inter-cellularly. Such a complex scheme requires cell type specific expression of a variety of metabolic enzymes and transporters. Glycogen supports neural elements during withdrawal of glucose, but once the limited buffer of glycogen is exhausted neural function fails and irreversible injury ensues. Under physiological conditions glycogen acts to provide supplemental substrates when ambient glucose is unable to support function during increased energy demand. Glycogen also supports learning and memory where it provides lactate to neurons during the conditioning phase of in vitro long-term potentiation (LTP), an experimental correlate of learning. Inhibiting the breakdown of glycogen or intercellular transport of lactate in in vivo rat models inhibits the retention of memory. Our current understanding of the importance of brain glycogen is expanding to encompass roles that are fundamental to higher brain function.
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Affiliation(s)
- Alice E. Waitt
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Liam Reed
- School of Life Sciences, University of NottinghamNottingham, UK
| | - Bruce R. Ransom
- Department of Neurology, University of WashingtonSeattle, WA, USA
| | - Angus M. Brown
- School of Life Sciences, University of NottinghamNottingham, UK
- Department of Neurology, University of WashingtonSeattle, WA, USA
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Tups A, Benzler J, Sergi D, Ladyman SR, Williams LM. Central Regulation of Glucose Homeostasis. Compr Physiol 2017; 7:741-764. [DOI: 10.1002/cphy.c160015] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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[ 18F]FDG PET signal is driven by astroglial glutamate transport. Nat Neurosci 2017; 20:393-395. [PMID: 28135241 PMCID: PMC5378483 DOI: 10.1038/nn.4492] [Citation(s) in RCA: 203] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/03/2017] [Indexed: 11/20/2022]
Abstract
Contributions of glial cells to neuroenergetics have been the focus of extensive debate. Here we provide the first positron emission tomography (PET) evidence that activation of the astrocytic glutamate transport via GLT-1 triggers widespread but graded glucose uptake in the rodent brain. Our results highlight the need for a reevaluation of the interpretation of [18F]FDG PET data, whereby astrocytes would be recognized to contribute significantly to the [18F]FDG signal.
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Hackett MJ, Sylvain NJ, Hou H, Caine S, Alaverdashvili M, Pushie MJ, Kelly ME. Concurrent Glycogen and Lactate Imaging with FTIR Spectroscopy To Spatially Localize Metabolic Parameters of the Glial Response Following Brain Ischemia. Anal Chem 2016; 88:10949-10956. [DOI: 10.1021/acs.analchem.6b02588] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mark J. Hackett
- Nanochemistry
Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia
| | - Nicole J. Sylvain
- Department
of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Suite B419 Health
Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Huishu Hou
- Department
of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Suite B419 Health
Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Sally Caine
- College
of Pharmacy and Nutrition, College of Medicine, University of Saskatchewan, 107 Wiggins
Road, Suite B221 Health Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Mariam Alaverdashvili
- College
of Pharmacy and Nutrition, College of Medicine, University of Saskatchewan, 107 Wiggins
Road, Suite B221 Health Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Michael J. Pushie
- Department
of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Suite B419 Health
Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Michael E. Kelly
- Department
of Surgery, Division of Neurosurgery, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Suite B419 Health
Sciences Building, Saskatoon, Saskatchewan S7N 5E5, Canada
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30
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Angleys H, Jespersen SN, Østergaard L. The Effects of Capillary Transit Time Heterogeneity (CTH) on the Cerebral Uptake of Glucose and Glucose Analogs: Application to FDG and Comparison to Oxygen Uptake. Front Comput Neurosci 2016; 10:103. [PMID: 27790110 PMCID: PMC5062759 DOI: 10.3389/fncom.2016.00103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 09/15/2016] [Indexed: 11/13/2022] Open
Abstract
Glucose is the brain's principal source of ATP, but the extent to which cerebral glucose consumption (CMRglc) is coupled with its oxygen consumption (CMRO2) remains unclear. Measurements of the brain's oxygen-glucose index OGI = CMRO2/CMRglc suggest that its oxygen uptake largely suffices for oxidative phosphorylation. Nevertheless, during functional activation and in some disease states, brain tissue seemingly produces lactate although cerebral blood flow (CBF) delivers sufficient oxygen, so-called aerobic glycolysis. OGI measurements, in turn, are method-dependent in that estimates based on glucose analog uptake depend on the so-called lumped constant (LC) to arrive at CMRglc. Capillary transit time heterogeneity (CTH), which is believed to change during functional activation and in some disease states, affects the extraction efficacy of oxygen from blood. We developed a three-compartment model of glucose extraction to examine whether CTH also affects glucose extraction into brain tissue. We then combined this model with our previous model of oxygen extraction to examine whether differential glucose and oxygen extraction might favor non-oxidative glucose metabolism under certain conditions. Our model predicts that glucose uptake is largely unaffected by changes in its plasma concentration, while changes in CBF and CTH affect glucose and oxygen uptake to different extents. Accordingly, functional hyperemia facilitates glucose uptake more than oxygen uptake, favoring aerobic glycolysis during enhanced energy demands. Applying our model to glucose analogs, we observe that LC depends on physiological state, with a risk of overestimating relative increases in CMRglc during functional activation by as much as 50%.
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Affiliation(s)
- Hugo Angleys
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus University Aarhus, Denmark
| | - Sune N Jespersen
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus UniversityAarhus, Denmark; Department of Physics and Astronomy, Aarhus UniversityAarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience and MINDLab, Aarhus UniversityAarhus, Denmark; Department of Neuroradiology, Aarhus University HospitalAarhus, Denmark
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An atypical distribution of lactate dehydrogenase isoenzymes in the hooded seal (Cystophora cristata) brain may reflect a biochemical adaptation to diving. J Comp Physiol B 2016; 186:373-86. [DOI: 10.1007/s00360-015-0956-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/29/2015] [Accepted: 12/04/2015] [Indexed: 12/13/2022]
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32
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Scharbarg E, Daenens M, Lemaître F, Geoffroy H, Guille-Collignon M, Gallopin T, Rancillac A. Astrocyte-derived adenosine is central to the hypnogenic effect of glucose. Sci Rep 2016; 6:19107. [PMID: 26755200 PMCID: PMC4709579 DOI: 10.1038/srep19107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/02/2015] [Indexed: 12/11/2022] Open
Abstract
Sleep has been hypothesised to maintain a close relationship with metabolism. Here we focus on the brain structure that triggers slow-wave sleep, the ventrolateral preoptic nucleus (VLPO), to explore the cellular and molecular signalling pathways recruited by an increase in glucose concentration. We used infrared videomicroscopy on ex vivo brain slices to establish that glucose induces vasodilations specifically in the VLPO via the astrocytic release of adenosine. Real-time detection by in situ purine biosensors further revealed that the adenosine level doubles in response to glucose, and triples during the wakefulness period. Finally, patch-clamp recordings uncovered the depolarizing effect of adenosine and its A2A receptor agonist, CGS-21680, on sleep-promoting VLPO neurons. Altogether, our results provide new insights into the metabolically driven release of adenosine. We hypothesise that adenosine adjusts the local energy supply to local neuronal activity in response to glucose. This pathway could contribute to sleep-wake transition and sleep intensity.
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Affiliation(s)
- Emeric Scharbarg
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Marion Daenens
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Frédéric Lemaître
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, Paris, F-75005, France
- CNRS, UMR 8640 Pasteur, Paris, F-75005, France
| | - Hélène Geoffroy
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Manon Guille-Collignon
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, Paris, F-75005, France
- CNRS, UMR 8640 Pasteur, Paris, F-75005, France
| | - Thierry Gallopin
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Armelle Rancillac
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
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Falkowska A, Gutowska I, Goschorska M, Nowacki P, Chlubek D, Baranowska-Bosiacka I. Energy Metabolism of the Brain, Including the Cooperation between Astrocytes and Neurons, Especially in the Context of Glycogen Metabolism. Int J Mol Sci 2015; 16:25959-81. [PMID: 26528968 PMCID: PMC4661798 DOI: 10.3390/ijms161125939] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/27/2015] [Accepted: 10/16/2015] [Indexed: 01/15/2023] Open
Abstract
Glycogen metabolism has important implications for the functioning of the brain, especially the cooperation between astrocytes and neurons. According to various research data, in a glycogen deficiency (for example during hypoglycemia) glycogen supplies are used to generate lactate, which is then transported to neighboring neurons. Likewise, during periods of intense activity of the nervous system, when the energy demand exceeds supply, astrocyte glycogen is immediately converted to lactate, some of which is transported to the neurons. Thus, glycogen from astrocytes functions as a kind of protection against hypoglycemia, ensuring preservation of neuronal function. The neuroprotective effect of lactate during hypoglycemia or cerebral ischemia has been reported in literature. This review goes on to emphasize that while neurons and astrocytes differ in metabolic profile, they interact to form a common metabolic cooperation.
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Affiliation(s)
- Anna Falkowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Izabela Gutowska
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Broniewskiego 24, 71-460 Szczecin, Poland.
| | - Marta Goschorska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Przemysław Nowacki
- Department of Neurology, Pomeranian Medical University, Unii Lubelskiej 1, 71-225 Szczecin, Poland.
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
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34
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Sharma RD, Katkar GD, Sundaram MS, Paul M, NaveenKumar SK, Swethakumar B, Hemshekhar M, Girish KS, Kemparaju K. Oxidative stress-induced methemoglobinemia is the silent killer during snakebite: a novel and strategic neutralization by melatonin. J Pineal Res 2015; 59:240-54. [PMID: 26103459 DOI: 10.1111/jpi.12256] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/19/2015] [Indexed: 12/20/2022]
Abstract
Oxidative stress-induced methemoglobinemia remained an untouched area in venom pharmacology till date. This study for the first time explored the potential of animal venoms to oxidize hemoglobin to methemoglobin. In in vitro whole-blood assay, methemoglobin forming ability of venoms varied as Naja naja > Ophiophagus hannah > Echis carinatus > Daboia russellii > Apis mellifera > Mesobuthus tamulus > Hippasa partita. Being highly potential, N. naja venom was further studied to observe methemoglobin formation in RBCs and in combinations with PMNs and PBMCs, where maximum effect was observed in RBCs + PMNs combination. Naja naja venom/externally added methemoglobin-induced methemoglobin formation was in parallel with ROS generation in whole blood/RBCs/RBCs + PMNs/RBCs + PBMCs. In in vivo studies, the lethal dose (1 mg/kg body weight, i.p.) of N. naja venom readily induced methemoglobin formation, ROS generation, expression of inflammatory markers, and hypoxia-inducible factor-3α. Although the mice administered with three effective doses of antivenom recorded zero mortality; the methemoglobin and ROS levels remained high. However, one effective dose of antivenom when administered along with melatonin (1:50; venom/melatonin, w/w), not only offered 100% survival of experimental mice, but also significantly reduced methemoglobin level, and oxidative stress markers including hypoxia-inducible factor-3α. This study provides strong drive that, complementing melatonin would not only reduce the antivenom load, but for sure greatly increase the success rate of antivenom therapy and drastically minimize the global incidence of snakebite deaths. However, further detailed investigations are needed before translating the combined therapy towards the bed side.
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Affiliation(s)
- Rachana D Sharma
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
| | - Gajanan D Katkar
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
| | | | - Manoj Paul
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
| | | | | | - Mahadevappa Hemshekhar
- Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, MB, Canada
| | - Kesturu S Girish
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
- Department of Studies and Research in Biochemistry, Tumkur University, Tumkur, India
| | - Kempaiah Kemparaju
- Department of Studies in Biochemistry, University of Mysore, Mysuru, India
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35
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Raichle ME. The restless brain: how intrinsic activity organizes brain function. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140172. [PMID: 25823869 PMCID: PMC4387513 DOI: 10.1098/rstb.2014.0172] [Citation(s) in RCA: 261] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2015] [Indexed: 11/12/2022] Open
Abstract
Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease.
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Affiliation(s)
- Marcus E Raichle
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 4525 Scott Avenue, Room 2116, St Louis, MO 63110, USA
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36
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Direct neuronal glucose uptake heralds activity-dependent increases in cerebral metabolism. Nat Commun 2015; 6:6807. [PMID: 25904018 PMCID: PMC4410436 DOI: 10.1038/ncomms7807] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 02/27/2015] [Indexed: 11/16/2022] Open
Abstract
Metabolically, the brain is a highly active organ that relies almost exclusively on glucose as its energy source. According to the astrocyte-to-neuron lactate shuttle hypothesis, glucose is taken up by astrocytes and converted to lactate, which is then oxidized by neurons. Here we show, using 2-photon imaging of a near-infrared 2-deoxyglucose analogue (2DG-IR), that glucose is taken up preferentially by neurons in awake behaving mice. Anesthesia suppressed neuronal 2DG-IR uptake and sensory stimulation was associated with a sharp increase in neuronal, but not astrocytic, 2DG-IR uptake. Moreover, hexokinase, which catalyze the first enzymatic steps in glycolysis, was highly enriched in neurons compared with astrocytes, in mouse as well as in human cortex. These observations suggest that brain activity and neuronal glucose metabolism are directly linked, and identifies the neuron as the principal locus of glucose uptake as visualized by functional brain imaging.
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37
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Fryer KL, Brown AM. Pluralistic roles for glycogen in the central and peripheral nervous systems. Metab Brain Dis 2015; 30:299-306. [PMID: 24610115 DOI: 10.1007/s11011-014-9516-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/24/2014] [Indexed: 11/24/2022]
Abstract
Glycogen is present in the mammalian nervous system, but at concentrations of up to one hundred times lower than those found in liver and skeletal muscle. This relatively low concentration has resulted in neglect of assigning a role(s) for brain glycogen, but in the last 15 years enormous progress has been made in revealing the multifaceted roles that glycogen plays in the mammalian nervous system. Initial studies highlighted a role for glycogen in supporting neural elements (neurons and axons) during aglycemia, where glycogen supplied supplementary energy substrate in the form of lactate to fuel neural oxidative metabolism. The appropriate enzymes and membrane bound transporters have been localized to cellular locations consistent with astrocyte to neuron energy substrate shuttling. A role for glycogen in supporting the induction of long term potential (LTP) in the hippocampus has recently been described, where glycogen is metabolized to lactate and shuttled to neurons via the extracellular space by monocarboxylate transporters, where it plays an integral role in the induction process of LTP. This is the first time that glycogen has been assigned a role in a distinct, complex physiological brain function, where the lack of glycogen, in the presence of normoglycemia, results in disturbance of the function. The signalling pathway that alerts astrocytes to increased neuronal activity has been recently described, highlighting a pivotal role for increased extracellular potassium ([K(+)]o) that routinely accompanies increased neural activity. An astrocyte membrane bound bicarbonate transporter is activated by the [K(+)]o, the resulting increase in intracellular bicarbonate alkalizing the cell's interior and activating soluble adenyl cyclase (sAC). The sAC promotes glycogenolysis via increases in cyclic AMP, ultimately producing lactate, which is shuttled out of the astrocyte and presumably taken up by neurons from the extracellular space.
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Affiliation(s)
- Kirsty L Fryer
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
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38
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Mason S, van Furth AM, Mienie LJ, Engelke UFH, Wevers RA, Solomons R, Reinecke CJ. A hypothetical astrocyte-microglia lactate shuttle derived from a 1H NMR metabolomics analysis of cerebrospinal fluid from a cohort of South African children with tuberculous meningitis. Metabolomics 2015; 11:822-837. [PMID: 26109926 PMCID: PMC4475545 DOI: 10.1007/s11306-014-0741-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/04/2014] [Indexed: 12/16/2022]
Abstract
Tuberculosis meningitis (TBM) is the most severe form of extra-pulmonary tuberculosis and is particularly intense in small children; there is no universally accepted algorithm for the diagnosis and substantiation of TB infection, which can lead to delayed intervention, a high risk factor for morbidity and mortality. In this study a proton magnetic resonance (1H NMR)-based metabolomics analysis and several chemometric methods were applied to data generated from lumber cerebrospinal fluid (CSF) samples from three experimental groups: (1) South African infants and children with confirmed TBM, (2) non-meningitis South African infants and children as controls, and (3) neurological controls from the Netherlands. A total of 16 NMR-derived CSF metabolites were identified, which clearly differentiated between the controls and TBM cases under investigation. The defining metabolites were the combination of perturbed glucose and highly elevated lactate, common to some other neurological disorders. The remaining 14 metabolites of the host's response to TBM were likewise mainly energy-associated indicators. We subsequently generated a hypothesis expressed as an "astrocyte-microglia lactate shuttle" (AMLS) based on the host's response, which emerged from the NMR-metabolomics information. Activation of microglia, as implied by the AMLS hypothesis, does not, however, present a uniform process and involves intricate interactions and feedback loops between the microglia, astrocytes and neurons that hamper attempts to construct basic and linear cascades of cause and effect; TBM involves a complex integration of the responses from the various cell types present within the CNS, with microglia and the astrocytes as main players.
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Affiliation(s)
- Shayne Mason
- Centre for Human Metabonomics, Faculty of Natural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, 2531 South Africa
| | - A. Marceline van Furth
- Department of Paediatric Infectious Diseases–Immunology and Rheumatology, Vrije Universiteit Medical Centre, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Lodewyk J. Mienie
- Potchefstroom Laboratory for Inborn Errors of Metabolism, Division for Biochemistry, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Udo F. H. Engelke
- Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Ron A. Wevers
- Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Regan Solomons
- Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 19063, Tygerberg, 7505 South Africa
| | - Carolus J. Reinecke
- Centre for Human Metabonomics, Faculty of Natural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, 2531 South Africa
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Abstract
Genetic, biochemical, pathological, and biomarker data demonstrate that Alzheimer's disease (AD) pathology, including the initiation and progressive buildup of insoluble forms of beta-amyloid (Aβ), appears to begin ~ 10-15 years prior to the onset of cognitive decline associated with AD. Metabolic dysfunction, a prominent feature of the evolving brain pathology, is reflected in a decline of total glucose utilization. Despite decades of interest in declining glucose use in AD no detailed consideration had been given to the possibility that this decline is not just a decline in energy consumption but rather in glycolysis alone. Glycolysis is a multi-step process that prepares the glucose molecule for oxidative phosphorylation and the generation of energy. In the normal brain, glycolysis exceeds that required for the needs of oxidative phosphorylation. Because it is occurring in a setting with adequate oxygen available for oxidative phosphorylation it is often referred to as aerobic glycolysis (AG). AG is a biomarker of a group of metabolic functions broadly supporting biosynthesis and neuroprotection. The distribution of AG in normal young adults correlates spatially with Aβ deposition in AD patients and cognitively normal individuals with elevated Aβ. In transgenic mice extracellular fluid Aβ and lactate, a marker of AG, vary in parallel regionally and with changes in activity. Reducing neuronal activity locally in transgenic mice attenuates plaque formation suggesting that plaque formation is an activity dependent process associated with aerobic glycolysis.
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40
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Swerdlow RH. Bioenergetic medicine. Br J Pharmacol 2014; 171:1854-69. [PMID: 24004341 DOI: 10.1111/bph.12394] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 08/17/2013] [Accepted: 08/22/2013] [Indexed: 12/12/2022] Open
Abstract
Here we discuss a specific therapeutic strategy we call 'bioenergetic medicine'. Bioenergetic medicine refers to the manipulation of bioenergetic fluxes to positively affect health. Bioenergetic medicine approaches rely heavily on the law of mass action, and impact systems that monitor and respond to the manipulated flux. Since classically defined energy metabolism pathways intersect and intertwine, targeting one flux also tends to change other fluxes, which complicates treatment design. Such indirect effects, fortunately, are to some extent predictable, and from a therapeutic perspective may also be desirable. Bioenergetic medicine-based interventions already exist for some diseases, and because bioenergetic medicine interventions are presently feasible, new approaches to treat certain conditions, including some neurodegenerative conditions and cancers, are beginning to transition from the laboratory to the clinic.
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Affiliation(s)
- Russell H Swerdlow
- Departments of Neurology, Molecular and Integrative Physiology, Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, KS, USA; Alzheimer's Disease Center, University of Kansas Medical Center, Fairway, KS, USA
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41
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Schurr A. Cerebral glycolysis: a century of persistent misunderstanding and misconception. Front Neurosci 2014; 8:360. [PMID: 25477776 PMCID: PMC4237041 DOI: 10.3389/fnins.2014.00360] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/21/2014] [Indexed: 11/18/2022] Open
Abstract
Since its discovery in 1780, lactate (lactic acid) has been blamed for almost any illness outcome in which its levels are elevated. Beginning in the mid-1980s, studies on both muscle and brain tissues, have suggested that lactate plays a role in bioenergetics. However, great skepticism and, at times, outright antagonism has been exhibited by many to any perceived role for this monocarboxylate in energy metabolism. The present review attempts to trace the negative attitudes about lactate to the first four or five decades of research on carbohydrate metabolism and its dogma according to which lactate is a useless anaerobic end-product of glycolysis. The main thrust here is the review of dozens of scientific publications, many by the leading scientists of their times, through the first half of the twentieth century. Consequently, it is concluded that there exists a barrier, described by Howard Margolis as “habit of mind,” that many scientists find impossible to cross. The term suggests “entrenched responses that ordinarily occur without conscious attention and that, even if noticed, are hard to change.” Habit of mind has undoubtedly played a major role in the above mentioned negative attitudes toward lactate. As early as the 1920s, scientists investigating brain carbohydrate metabolism had discovered that lactate can be oxidized by brain tissue preparations, yet their own habit of mind redirected them to believe that such an oxidation is simply a disposal mechanism of this “poisonous” compound. The last section of the review invites the reader to consider a postulated alternative glycolytic pathway in cerebral and, possibly, in most other tissues, where no distinction is being made between aerobic and anaerobic glycolysis; lactate is always the glycolytic end product. Aerobically, lactate is readily shuttled and transported into the mitochondrion, where it is converted to pyruvate via a mitochondrial lactate dehydrogenase (mLDH) and then is entered the tricarboxylic acid (TCA) cycle.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, University of Louisville School of Medicine Louisville, KY, USA
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42
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Inhibition of lactate dehydrogenase activity as an approach to cancer therapy. Future Med Chem 2014; 6:429-45. [PMID: 24635523 DOI: 10.4155/fmc.13.206] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the attempt of developing innovative anticancer treatments, growing interest has recently focused on the peculiar metabolic properties of cancer cells. In this context, LDH, which converts pyruvate to lactate at the end of glycolysis, is emerging as one of the most interesting molecular targets for the development of new inhibitors. In fact, because LDH activity is not needed for pyruvate metabolism through the TCA cycle, inhibitors of this enzyme should spare glucose metabolism of normal non-proliferating cells, which usually completely degrade the glucose molecule to CO2. This review is aimed at summarizing the available data on LDH biology in normal and neoplastic cells, which support the anticancer therapeutic approach based on LDH inhibition. These data encouraged pharmaceutical industries and academic institutions in the search of small-molecule inhibitors and promising candidates have recently been identified. The availability of inhibitors with drug-like properties will allow the evaluation in the near future of the real potential of LDH inhibition in anticancer treatment, also making the identification of the most responsive neoplastic conditions possible.
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Iron transport across the blood-brain barrier: development, neurovascular regulation and cerebral amyloid angiopathy. Cell Mol Life Sci 2014; 72:709-27. [PMID: 25355056 DOI: 10.1007/s00018-014-1771-4] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/10/2014] [Accepted: 10/23/2014] [Indexed: 12/14/2022]
Abstract
There are two barriers for iron entry into the brain: (1) the brain-cerebrospinal fluid (CSF) barrier and (2) the blood-brain barrier (BBB). Here, we review the literature on developmental iron accumulation by the brain, focusing on the transport of iron through the brain microvascular endothelial cells (BMVEC) of the BBB. We review the iron trafficking proteins which may be involved in the iron flux across BMVEC and discuss the plausible mechanisms of BMVEC iron uptake and efflux. We suggest a model for how BMVEC iron uptake and efflux are regulated and a mechanism by which the majority of iron is trafficked across the developing BBB under the direct guidance of neighboring astrocytes. Thus, we place brain iron uptake in the context of the neurovascular unit of the adult brain. Last, we propose that BMVEC iron is involved in the aggregation of amyloid-β peptides leading to the progression of cerebral amyloid angiopathy which often occurs prior to dementia and the onset of Alzheimer's disease.
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Oria M, Jalan R. Brain lactate in hepatic encephalopathy: friend or foe? J Hepatol 2014; 60:476-7. [PMID: 24308990 DOI: 10.1016/j.jhep.2013.11.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 01/12/2023]
Affiliation(s)
- Marc Oria
- Liver Failure Group, UCL Institute for Liver and Digestive Health, The Royal Free Hospital, Pond Street, London NW3 2PF, United Kingdom
| | - Rajiv Jalan
- Liver Failure Group, UCL Institute for Liver and Digestive Health, The Royal Free Hospital, Pond Street, London NW3 2PF, United Kingdom.
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Quantitative proteomics analysis highlights the role of redox hemostasis and energy metabolism in human embryonic stem cell differentiation to neural cells. J Proteomics 2014; 101:1-16. [PMID: 24530625 DOI: 10.1016/j.jprot.2014.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 01/16/2014] [Accepted: 02/01/2014] [Indexed: 01/15/2023]
Abstract
UNLABELLED Neural differentiation of human embryonic stem cells (hESCs) is a unique opportunity for in vitro analyses of neurogenesis in humans. Extrinsic cues through neural plate formation are well described in the hESCs although intracellular mechanisms underlying neural development are largely unknown. Proteome analysis of hESC differentiation to neural cells will help to further define molecular mechanisms involved in neurogenesis in humans. Using a two-dimensional differential gel electrophoresis (2D-DIGE) system, we analyzed the proteome of hESC differentiation to neurons at three stages, early neural differentiation, neural ectoderm and mature neurons. Out of 137 differentially accumulated protein spots, 118 spots were identified using MALDI-TOF/TOF and LC MS/MS. We observed that proteins involved in redox hemostasis, vitamin and energy metabolism and ubiquitin dependent proteolysis were more abundant in differentiated cells, whereas the abundance of proteins associated with RNA processing and protein folding was higher in hESCs. Higher abundance of proteins involved in maintaining cellular redox state suggests the importance of redox hemostasis in neural differentiation. Furthermore, our results support the concept of a coupling mechanism between neuronal activity and glucose utilization. The protein network analysis showed that the majority of the interacting proteins were associated with the cell cycle and cellular proliferation. These results enhanced our understanding of the molecular dynamics that underlie neural commitment and differentiation. BIOLOGICAL SIGNIFICANCE In highlighting the role of redox and unique metabolic properties of neuronal cells, the present findings add insight to our understanding of hESC differentiation to neurons. The abundance of fourteen proteins involved in maintaining cellular redox state, including 10 members of peroxiredoxin (Prdx) family, mainly increased during differentiation, thus highlighting a link of neural differentiation to redox. Our results revealed markedly higher expression of genes encoding enzymes involved in the glycolysis and amino acid synthesis during differentiation. Protein network analysis predicted a number of critical mediators in hESC differentiation. These proteins included TP53, CTNNB1, SMARCA4, TNF, TERT, E2F1, MYC, RB1, and AR.
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Vardjan N, Kreft M, Zorec R. Regulated Exocytosis in Astrocytes is as Slow as the Metabolic Availability of Gliotransmitters: Focus on Glutamate and ATP. GLUTAMATE AND ATP AT THE INTERFACE OF METABOLISM AND SIGNALING IN THE BRAIN 2014; 11:81-101. [DOI: 10.1007/978-3-319-08894-5_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Rodrigues TB, Valette J, Bouzier-Sore AK. (13)C NMR spectroscopy applications to brain energy metabolism. FRONTIERS IN NEUROENERGETICS 2013; 5:9. [PMID: 24367329 PMCID: PMC3856424 DOI: 10.3389/fnene.2013.00009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 11/15/2013] [Indexed: 12/31/2022]
Abstract
(13)C nuclear magnetic resonance (NMR) spectroscopy is the method of choice for studying brain metabolism. Indeed, the most convincing data obtained to decipher metabolic exchanges between neurons and astrocytes have been obtained using this technique, thus illustrating its power. It may be difficult for non-specialists, however, to grasp thefull implication of data presented in articles written by spectroscopists. The aim of the review is, therefore, to provide a fundamental understanding of this topic to facilitate the non-specialists in their reading of this literature. In the first part of this review, we present the metabolic fate of (13)C-labeled substrates in the brain in a detailed way, including an overview of some general neurochemical principles. We also address and compare the various spectroscopic strategies that can be used to study brain metabolism. Then, we provide an overview of the (13)C NMR experiments performed to analyze both intracellular and intercellular metabolic fluxes. More particularly, the role of lactate as a potential energy substrate for neurons is discussed in the light of (13)C NMR data. Finally, new perspectives and applications offered by (13)C hyperpolarization are described.
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Affiliation(s)
- Tiago B. Rodrigues
- Cancer Research UK Cambridge Institute and Department of Biochemistry, University of CambridgeCambridge, UK
| | - Julien Valette
- Commissariat à l’Energie Atomique, Institut d’Imagerie Biomédicale, Molecular Imaging Research CenterFontenay-Aux-Roses, France
| | - Anne-Karine Bouzier-Sore
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, Université Bordeaux Segalen - Centre National de la Recherche ScientifiqueBordeaux, France
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Gan X, Huang S, Wu L, Wang Y, Hu G, Li G, Zhang H, Yu H, Swerdlow RH, Chen JX, Yan SS. Inhibition of ERK-DLP1 signaling and mitochondrial division alleviates mitochondrial dysfunction in Alzheimer's disease cybrid cell. Biochim Biophys Acta Mol Basis Dis 2013; 1842:220-31. [PMID: 24252614 DOI: 10.1016/j.bbadis.2013.11.009] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/27/2013] [Accepted: 11/11/2013] [Indexed: 02/05/2023]
Abstract
Mitochondrial dysfunction is an early pathological feature of Alzheimer's disease (AD). The underlying mechanisms and strategies to repair it remain unclear. Here, we demonstrate for the first time the direct consequences and potential mechanisms of mitochondrial functional defects associated with abnormal mitochondrial dynamics in AD. Using cytoplasmic hybrid (cybrid) neurons with incorporated platelet mitochondria from AD and age-matched non-AD human subjects into mitochondrial DNA (mtDNA)-depleted neuronal cells, we observed that AD cybrid cells had significant changes in morphology and function; such changes associate with altered expression and distribution of dynamin-like protein (DLP1) and mitofusin 2 (Mfn2). Treatment with antioxidant protects against AD mitochondria-induced extracellular signal-regulated kinase (ERK) activation and mitochondrial fission-fusion imbalances. Notably, inhibition of ERK activation not only attenuates aberrant mitochondrial morphology and function but also restores the mitochondrial fission and fusion balance. These effects suggest a role of oxidative stress-mediated ERK signal transduction in modulation of mitochondrial fission and fusion events. Further, blockade of the mitochondrial fission protein DLP1 by a genetic manipulation with a dominant negative DLP1 (DLP1(K38A)), its expression with siRNA-DLP1, or inhibition of mitochondrial division with mdivi-1 attenuates mitochondrial functional defects observed in AD cybrid cells. Our results provide new insights into mitochondrial dysfunction resulting from changes in the ERK-fission/fusion (DLP1) machinery and signaling pathway. The protective effect of mdivi-1 and inhibition of ERK signaling on maintenance of normal mitochondrial structure and function holds promise as a potential novel therapeutic strategy for AD.
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Affiliation(s)
- Xueqi Gan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du 610041, China
| | - Shengbin Huang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du 610041, China
| | - Long Wu
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Yongfu Wang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Gang Hu
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Guangyue Li
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du 610041, China
| | - Hongju Zhang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du 610041, China
| | | | - John Xi Chen
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY 1003, USA
| | - Shirley ShiDu Yan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA.
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An J, Haile WB, Wu F, Torre E, Yepes M. Tissue-type plasminogen activator mediates neuroglial coupling in the central nervous system. Neuroscience 2013; 257:41-8. [PMID: 24200922 DOI: 10.1016/j.neuroscience.2013.10.060] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/23/2013] [Accepted: 10/24/2013] [Indexed: 02/07/2023]
Abstract
The interaction between neurons, astrocytes and endothelial cells plays a central role coupling energy supply with changes in neuronal activity. For a long time it was believed that glucose was the only source of energy for neurons. However, a growing body of experimental evidence indicates that lactic acid, generated by aerobic glycolysis in perivascular astrocytes, is also a source of energy for neuronal activity, particularly when the supply of glucose from the intravascular space is interrupted. Adenosine monophosphate-activated protein kinase (AMPK) is an evolutionary conserved kinase that couples cellular activity with energy consumption via induction of the uptake of glucose and activation of the glycolytic pathway. The uptake of glucose by the blood-brain barrier is mediated by glucose transporter-1 (GLUT1), which is abundantly expressed in endothelial cells and astrocytic end-feet processes. Tissue-type plasminogen activator (tPA) is a serine proteinase that is found in endothelial cells, astrocytes and neurons. Genetic overexpression of neuronal tPA or treatment with recombinant tPA protects neurons from the deleterious effects of metabolic stress or excitotoxicity, via a mechanism independent of tPA's ability to cleave plasminogen into plasmin. The work presented here shows that exposure to metabolic stress induces the rapid release of tPA from murine neurons but not from astrocytes. This tPA induces AMPK activation, membrane recruitment of GLUT1, and GLUT1-mediated glucose uptake in astrocytes and endothelial cells. Our data indicate that this is followed by the synthesis and release of lactic acid from astrocytes, and that the uptake of this lactic acid via the monocarboxylate transporter-2 promotes survival in neurons exposed to metabolic stress.
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Affiliation(s)
- J An
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA; Department of Pharmacology, Shandong University School of Medicine, Jinan, China
| | - W B Haile
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - F Wu
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - E Torre
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - M Yepes
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA; Department of Neurology, Veterans Affairs Medical Center, Atlanta, GA, USA.
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Aerobic glycolysis in the primate brain: reconsidering the implications for growth and maintenance. Brain Struct Funct 2013; 219:1149-67. [DOI: 10.1007/s00429-013-0662-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/15/2013] [Indexed: 12/15/2022]
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