1
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Rothman DL, Behar KL, Dienel GA. Mechanistic stoichiometric relationship between the rates of neurotransmission and neuronal glucose oxidation: Reevaluation of and alternatives to the pseudo-malate-aspartate shuttle model. J Neurochem 2024; 168:555-591. [PMID: 36089566 DOI: 10.1111/jnc.15619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 04/08/2022] [Accepted: 04/15/2022] [Indexed: 11/26/2022]
Abstract
The ~1:1 stoichiometry between the rates of neuronal glucose oxidation (CMRglc-ox-N) and glutamate (Glu)/γ-aminobutyric acid (GABA)-glutamine (Gln) neurotransmitter (NT) cycling between neurons and astrocytes (VNTcycle) has been firmly established. However, the mechanistic basis for this relationship is not fully understood, and this knowledge is critical for the interpretation of metabolic and brain imaging studies in normal and diseased brain. The pseudo-malate-aspartate shuttle (pseudo-MAS) model established the requirement for glycolytic metabolism in cultured glutamatergic neurons to produce NADH that is shuttled into mitochondria to support conversion of extracellular Gln (i.e., astrocyte-derived Gln in vivo) into vesicular neurotransmitter Glu. The evaluation of this model revealed that it could explain half of the 1:1 stoichiometry and it has limitations. Modifications of the pseudo-MAS model were, therefore, devised to address major knowledge gaps, that is, submitochondrial glutaminase location, identities of mitochondrial carriers for Gln and other model components, alternative mechanisms to transaminate α-ketoglutarate to form Glu and shuttle glutamine-derived ammonia while maintaining mass balance. All modified models had a similar 0.5 to 1.0 predicted mechanistic stoichiometry between VNTcycle and the rate of glucose oxidation. Based on studies of brain β-hydroxybutyrate oxidation, about half of CMRglc-ox-N may be linked to glutamatergic neurotransmission and localized in pre-synaptic structures that use pseudo-MAS type mechanisms for Glu-Gln cycling. In contrast, neuronal compartments that do not participate in transmitter cycling may use the MAS to sustain glucose oxidation. The evaluation of subcellular compartmentation of neuronal glucose metabolism in vivo is a critically important topic for future studies to understand glutamatergic and GABAergic neurotransmission.
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Affiliation(s)
- Douglas L Rothman
- Magnetic Resonance Research Center and Departments of Radiology and Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Kevin L Behar
- Magnetic Resonance Research Center and Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
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2
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Rose HM, Ferrán B, Ranjit R, Masingale AM, Owen DB, Hussong S, Kinter MT, Galvan V, Logan S, Díaz-García CM. Mitochondrial calcium uniporter deficiency in dentate granule cells remodels neuronal metabolism and impairs reversal learning. J Neurochem 2024; 168:592-607. [PMID: 37415312 PMCID: PMC10770303 DOI: 10.1111/jnc.15901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/27/2023] [Accepted: 06/12/2023] [Indexed: 07/08/2023]
Abstract
The mitochondrial calcium uniporter (MCU) is the main route of calcium (Ca2+) entry into neuronal mitochondria. This channel has been linked to mitochondrial Ca2+ overload and cell death under neurotoxic conditions, but its physiologic roles for normal brain function remain poorly understood. Despite high expression of MCU in excitatory hippocampal neurons, it is unknown whether this channel is required for learning and memory. Here, we genetically down-regulated the Mcu gene in dentate granule cells (DGCs) of the hippocampus and found that this manipulation increases the overall respiratory activity of mitochondrial complexes I and II, augmenting the generation of reactive oxygen species in the context of impaired electron transport chain. The metabolic remodeling of MCU-deficient neurons also involved changes in the expression of enzymes that participate in glycolysis and the regulation of the tricarboxylic acid cycle, as well as the cellular antioxidant defenses. We found that MCU deficiency in DGCs does not change circadian rhythms, spontaneous exploratory behavior, or cognitive function in middle-aged mice (11-13 months old), when assessed with a food-motivated working memory test with three choices. DGC-targeted down-regulation of MCU significantly impairs reversal learning assessed with an 8-arm radial arm water maze but does not affect their ability to learn the task for the first time. Our results indicate that neuronal MCU plays an important physiologic role in memory formation and may be a potential therapeutic target to develop interventions aimed at improving cognitive function in aging, neurodegenerative diseases, and brain injury.
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Affiliation(s)
- Hadyn M Rose
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Beatriz Ferrán
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Rojina Ranjit
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Anthony M Masingale
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Daniel B Owen
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Stacy Hussong
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Oklahoma City Veterans Health Care System, Oklahoma City, Oklahoma, USA
| | - Michael T Kinter
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Veronica Galvan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
- Oklahoma City Veterans Health Care System, Oklahoma City, Oklahoma, USA
| | - Sreemathi Logan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
| | - Carlos Manlio Díaz-García
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Center for Geroscience and Healthy Brain Aging, Oklahoma City, Oklahoma, USA
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3
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Pannoni KE, Fischer QS, Tarannum R, Cawley ML, Alsalman MM, Acosta N, Ezigbo C, Gil DV, Campbell LA, Farris S. MCU-enriched dendritic mitochondria regulate plasticity in distinct hippocampal circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.10.566606. [PMID: 37986798 PMCID: PMC10659405 DOI: 10.1101/2023.11.10.566606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Mitochondria are dynamic organelles that are morphologically and functionally diverse across cell types and subcellular compartments in order to meet unique energy demands. Mitochondrial dysfunction has been implicated in a wide variety of neurological disorders, including psychiatric disorders like schizophrenia and bipolar disorder. Despite it being well known that mitochondria are essential for synaptic transmission and synaptic plasticity, the mechanisms regulating mitochondria in support of normal synapse function are incompletely understood. The mitochondrial calcium uniporter (MCU) regulates calcium entry into the mitochondria, which in turn regulates the bioenergetics and distribution of mitochondria to active synapses. Evidence suggests that calcium influx via MCU couples neuronal activity to mitochondrial metabolism and ATP production, which would allow neurons to rapidly adapt to changing energy demands. Intriguingly, MCU is uniquely enriched in hippocampal CA2 distal dendrites relative to neighboring hippocampal CA1 or CA3 distal dendrites, however, the functional significance of this enrichment is not clear. Synapses from the entorhinal cortex layer II (ECII) onto CA2 distal dendrites readily express long term potentiation (LTP), unlike the LTP-resistant synapses from CA3 onto CA2 proximal dendrites, but the mechanisms underlying these different plasticity profiles are unknown. We hypothesized that enrichment of MCU near ECII-CA2 synapses promotes LTP in an otherwise plasticity-restricted cell type. Using a CA2-specific MCU knockout (cKO) mouse, we found that MCU is required for LTP at distal dendrite synapses but does not affect the lack of LTP at proximal dendrite synapses. Loss of LTP at ECII-CA2 synapses correlated with a trend for decreased spine density in CA2 distal dendrites of cKO mice compared to control (CTL) mice, which was predominantly seen in immature spines. Moreover, mitochondria were significantly smaller and more numerous across all dendritic layers of CA2 in cKO mice compared to CTL mice, suggesting an overall increase in mitochondrial fragmentation. Fragmented mitochondria might have functional changes, such as altered ATP production, that might explain a deficit in synaptic plasticity. Collectively, our data reveal that MCU regulates layer-specific forms of plasticity in CA2 dendrites, potentially by maintaining proper mitochondria morphology and distribution within dendrites. Differences in MCU expression across different cell types and circuits might be a general mechanism to tune the sensitivity of mitochondria to cytoplasmic calcium levels to power synaptic plasticity.
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Affiliation(s)
- Katy E. Pannoni
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Quentin S. Fischer
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Renesa Tarannum
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mikel L. Cawley
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia
| | - Mayd M. Alsalman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Nicole Acosta
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Chisom Ezigbo
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Daniela V. Gil
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Logan A. Campbell
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Shannon Farris
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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4
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Wang Y, Patti GJ. The Warburg effect: a signature of mitochondrial overload. Trends Cell Biol 2023; 33:1014-1020. [PMID: 37117116 PMCID: PMC10600323 DOI: 10.1016/j.tcb.2023.03.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/30/2023]
Abstract
A long-standing question in cancer biology has been why oxygenated tumors ferment the majority of glucose they consume to lactate rather than oxidizing it in their mitochondria, a phenomenon known as the 'Warburg effect.' An abundance of evidence shows not only that most cancer cells have fully functional mitochondria but also that mitochondrial activity is important to proliferation. It is therefore difficult to rationalize the metabolic benefit of cancer cells switching from respiration to fermentation. An emerging perspective is that rather than mitochondrial metabolism being suppressed in tumors, as is often suggested, mitochondrial activity increases to the level of saturation. As such, the Warburg effect becomes a signature of excess glucose being released as lactate due to mitochondrial overload.
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Affiliation(s)
- Yahui Wang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gary J Patti
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130, USA; Siteman Cancer Center, Washington University in St. Louis, St. Louis, MO 63130, USA.
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5
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Johnson GA, Krishnamoorthy RR, Stankowska DL. Modulating mitochondrial calcium channels (TRPM2/MCU/NCX) as a therapeutic strategy for neurodegenerative disorders. Front Neurosci 2023; 17:1202167. [PMID: 37928737 PMCID: PMC10622973 DOI: 10.3389/fnins.2023.1202167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Efficient cellular communication is essential for the brain to regulate diverse functions like muscle contractions, memory formation and recall, decision-making, and task execution. This communication is facilitated by rapid signaling through electrical and chemical messengers, including voltage-gated ion channels and neurotransmitters. These messengers elicit broad responses by propagating action potentials and mediating synaptic transmission. Calcium influx and efflux are essential for releasing neurotransmitters and regulating synaptic transmission. Mitochondria, which are involved in oxidative phosphorylation, and the energy generation process, also interact with the endoplasmic reticulum to store and regulate cytoplasmic calcium levels. The number, morphology, and distribution of mitochondria in different cell types vary based on energy demands. Mitochondrial damage can cause excess reactive oxygen species (ROS) generation. Mitophagy is a selective process that targets and degrades damaged mitochondria via autophagosome-lysosome fusion. Defects in mitophagy can lead to a buildup of ROS and cell death. Numerous studies have attempted to characterize the relationship between mitochondrial dysfunction and calcium dysregulation in neurodegenerative diseases such as Alzheimer's Disease, Parkinson's Disease, Huntington's Disease, Amyotrophic lateral sclerosis, spinocerebellar ataxia, and aging. Interventional strategies to reduce mitochondrial damage and accumulation could serve as a therapeutic target, but further research is needed to unravel this potential. This review offers an overview of calcium signaling related to mitochondria in various neuronal cells. It critically examines recent findings, exploring the potential roles that mitochondrial dysfunction might play in multiple neurodegenerative diseases and aging. Furthermore, the review identifies existing gaps in knowledge to guide the direction of future research.
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Affiliation(s)
- Gretchen A. Johnson
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
- Department of Microbiology, Immunology and Genetics, School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Raghu R. Krishnamoorthy
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
- Department of Pharmacology and Neuroscience, School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Dorota L. Stankowska
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
- Department of Microbiology, Immunology and Genetics, School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, United States
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6
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González-Moreno L, Santamaría-Cano A, Paradela A, Martínez-Chantar ML, Martín MÁ, Pérez-Carreras M, García-Picazo A, Vázquez J, Calvo E, González-Aseguinolaza G, Saheki T, del Arco A, Satrústegui J, Contreras L. Exogenous aralar/slc25a12 can replace citrin/slc25a13 as malate aspartate shuttle component in liver. Mol Genet Metab Rep 2023; 35:100967. [PMID: 36967723 PMCID: PMC10031141 DOI: 10.1016/j.ymgmr.2023.100967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
The deficiency of CITRIN, the liver mitochondrial aspartate-glutamate carrier (AGC), is the cause of four human clinical phenotypes, neonatal intrahepatic cholestasis caused by CITRIN deficiency (NICCD), silent period, failure to thrive and dyslipidemia caused by CITRIN deficiency (FTTDCD), and citrullinemia type II (CTLN2). Clinical symptoms can be traced back to disruption of the malate-aspartate shuttle due to the lack of citrin. A potential therapy for this condition is the expression of aralar, the AGC present in brain, to replace citrin. To explore this possibility we have first verified that the NADH/NAD+ ratio increases in hepatocytes from citrin(-/-) mice, and then found that exogenous aralar expression reversed the increase in NADH/NAD+ observed in these cells. Liver mitochondria from citrin (-/-) mice expressing liver specific transgenic aralar had a small (~ 4-6 nmoles x mg prot-1 x min-1) but consistent increase in malate aspartate shuttle (MAS) activity over that of citrin(-/-) mice. These results support the functional replacement between AGCs in the liver. To explore the significance of AGC replacement in human therapy we studied the relative levels of citrin and aralar in mouse and human liver through absolute quantification proteomics. We report that mouse liver has relatively high aralar levels (citrin/aralar molar ratio of 7.8), whereas human liver is virtually devoid of aralar (CITRIN/ARALAR ratio of 397). This large difference in endogenous aralar levels partly explains the high residual MAS activity in liver of citrin(-/-) mice and why they fail to recapitulate the human disease, but supports the benefit of increasing aralar expression to improve the redox balance capacity of human liver, as an effective therapy for CITRIN deficiency.
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7
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Kane DA, Foo ACY, Noftall EB, Brebner K, Marangoni DG. Lactate shuttling as an allostatic means of thermoregulation in the brain. Front Neurosci 2023; 17:1144639. [PMID: 37250407 PMCID: PMC10217782 DOI: 10.3389/fnins.2023.1144639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 04/18/2023] [Indexed: 05/31/2023] Open
Abstract
Lactate, the redox-balanced end product of glycolysis, travels within and between cells to fulfill an array of physiologic functions. While evidence for the centrality of this lactate shuttling in mammalian metabolism continues to mount, its application to physical bioenergetics remains underexplored. Lactate represents a metabolic "cul-de-sac," as it can only re-enter metabolism by first being converted back to pyruvate by lactate dehydrogenase (LDH). Given the differential distribution of lactate producing/consuming tissues during metabolic stresses (e.g., exercise), we hypothesize that lactate shuttling vis-à-vis the exchange of extracellular lactate between tissues serves a thermoregulatory function, i.e., an allostatic strategy to mitigate the consequences of elevated metabolic heat. To explore this idea, the rates of heat and respiratory oxygen consumption in saponin-permeabilized rat cortical brain samples fed lactate or pyruvate were measured. Heat and respiratory oxygen consumption rates, and calorespirometric ratios were lower during lactate vs. pyruvate-linked respiration. These results support the hypothesis of allostatic thermoregulation in the brain with lactate.
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Affiliation(s)
- Daniel A. Kane
- Department of Human Kinetics, St. Francis Xavier University, Antigonish, NS, Canada
| | - Alexander C. Y. Foo
- Department of Chemistry, St. Francis Xavier University, Antigonish, NS, Canada
| | - Erin B. Noftall
- Department of Human Kinetics, St. Francis Xavier University, Antigonish, NS, Canada
| | - Karen Brebner
- Department of Psychology, St. Francis Xavier University, Antigonish, NS, Canada
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8
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del Arco A, González-Moreno L, Pérez-Liébana I, Juaristi I, González-Sánchez P, Contreras L, Pardo B, Satrústegui J. Regulation of neuronal energy metabolism by calcium: Role of MCU and Aralar/malate-aspartate shuttle. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2023; 1870:119468. [PMID: 36997074 DOI: 10.1016/j.bbamcr.2023.119468] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
Calcium is a major regulator of cellular metabolism. Calcium controls mitochondrial respiration, and calcium signaling is used to meet cellular energetic demands through energy production in the organelle. Although it has been widely assumed that Ca2+-actions require its uptake by mitochondrial calcium uniporter (MCU), alternative pathways modulated by cytosolic Ca2+ have been recently proposed. Recent findings have indicated a role for cytosolic Ca2+ signals acting on mitochondrial NADH shuttles in the control of cellular metabolism in neurons using glucose as fuel. It has been demonstrated that AGC1/Aralar, the component of the malate/aspartate shuttle (MAS) regulated by cytosolic Ca2+, participates in the maintenance of basal respiration exerted through Ca2+-fluxes between ER and mitochondria, whereas mitochondrial Ca2+-uptake by MCU does not contribute. Aralar/MAS pathway, activated by small cytosolic Ca2+ signals, provides in fact substrates, redox equivalents and pyruvate, fueling respiration. Upon activation and increases in workload, neurons upregulate OxPhos, cytosolic pyruvate production and glycolysis, together with glucose uptake, in a Ca2+-dependent way, and part of this upregulation is via Ca2+ signaling. Both MCU and Aralar/MAS contribute to OxPhos upregulation, Aralar/MAS playing a major role, especially at small and submaximal workloads. Ca2+ activation of Aralar/MAS, by increasing cytosolic NAD+/NADH provides Ca2+-dependent increases in glycolysis and cytosolic pyruvate production priming respiration as a feed-forward mechanism in response to workload. Thus, except for glucose uptake, these processes are dependent on Aralar/MAS, whereas MCU is the relevant target for Ca2+ signaling when MAS is bypassed, by using pyruvate or β-hydroxybutyrate as substrates.
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9
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Meyer DJ, Díaz-García CM, Nathwani N, Rahman M, Yellen G. The Na +/K + pump dominates control of glycolysis in hippocampal dentate granule cells. eLife 2022; 11:e81645. [PMID: 36222651 PMCID: PMC9592084 DOI: 10.7554/elife.81645] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Cellular ATP that is consumed to perform energetically expensive tasks must be replenished by new ATP through the activation of metabolism. Neuronal stimulation, an energetically demanding process, transiently activates aerobic glycolysis, but the precise mechanism underlying this glycolysis activation has not been determined. We previously showed that neuronal glycolysis is correlated with Ca2+ influx, but is not activated by feedforward Ca2+ signaling (Díaz-García et al., 2021a). Since ATP-powered Na+ and Ca2+ pumping activities are increased following stimulation to restore ion gradients and are estimated to consume most neuronal ATP, we aimed to determine if they are coupled to neuronal glycolysis activation. By using two-photon imaging of fluorescent biosensors and dyes in dentate granule cell somas of acute mouse hippocampal slices, we observed that production of cytoplasmic NADH, a byproduct of glycolysis, is strongly coupled to changes in intracellular Na+, while intracellular Ca2+ could only increase NADH production if both forward Na+/Ca2+ exchange and Na+/K+ pump activity were intact. Additionally, antidromic stimulation-induced intracellular [Na+] increases were reduced >50% by blocking Ca2+ entry. These results indicate that neuronal glycolysis activation is predominantly a response to an increase in activity of the Na+/K+ pump, which is strongly potentiated by Na+ influx through the Na+/Ca2+ exchanger during extrusion of Ca2+ following stimulation.
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Affiliation(s)
- Dylan J Meyer
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | | | - Nidhi Nathwani
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Mahia Rahman
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
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10
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Zampese E, Wokosin DL, Gonzalez-Rodriguez P, Guzman JN, Tkatch T, Kondapalli J, Surmeier WC, D’Alessandro KB, De Stefani D, Rizzuto R, Iino M, Molkentin JD, Chandel NS, Schumacker PT, Surmeier DJ. Ca 2+ channels couple spiking to mitochondrial metabolism in substantia nigra dopaminergic neurons. SCIENCE ADVANCES 2022; 8:eabp8701. [PMID: 36179023 PMCID: PMC9524841 DOI: 10.1126/sciadv.abp8701] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 08/12/2022] [Indexed: 05/08/2023]
Abstract
How do neurons match generation of adenosine triphosphate by mitochondria to the bioenergetic demands of regenerative activity? Although the subject of speculation, this coupling is still poorly understood, particularly in neurons that are tonically active. To help fill this gap, pacemaking substantia nigra dopaminergic neurons were studied using a combination of optical, electrophysiological, and molecular approaches. In these neurons, spike-activated calcium (Ca2+) entry through Cav1 channels triggered Ca2+ release from the endoplasmic reticulum, which stimulated mitochondrial oxidative phosphorylation through two complementary Ca2+-dependent mechanisms: one mediated by the mitochondrial uniporter and another by the malate-aspartate shuttle. Disrupting either mechanism impaired the ability of dopaminergic neurons to sustain spike activity. While this feedforward control helps dopaminergic neurons meet the bioenergetic demands associated with sustained spiking, it is also responsible for their elevated oxidant stress and possibly to their decline with aging and disease.
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Affiliation(s)
- Enrico Zampese
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - David L. Wokosin
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Patricia Gonzalez-Rodriguez
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jaime N. Guzman
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Tatiana Tkatch
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Jyothisri Kondapalli
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - William C. Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Karis B. D’Alessandro
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy
| | - Masamitsu Iino
- Department of Physiology, Nihon University School of Medicine, 30-1, Oyaguchi Kami-cho, Itabashi-ku, Tokyo 173-8610, Japan
| | - Jeffery D. Molkentin
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Navdeep S. Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - D. James Surmeier
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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11
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Dhoundiyal A, Goeschl V, Boehm S, Kubista H, Hotka M. Glycerol-3-Phosphate Shuttle Is a Backup System Securing Metabolic Flexibility in Neurons. J Neurosci 2022; 42:7339-7354. [PMID: 35999055 PMCID: PMC9525167 DOI: 10.1523/jneurosci.0193-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 08/05/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Electrical activity in neurons is highly energy demanding and accompanied by rises in cytosolic Ca2+ Cytosolic Ca2+, in turn, secures energy supply by pushing mitochondrial metabolism either through augmented NADH (nicotinamide adenine dinucleotide) transfer into mitochondria via the malate-aspartate shuttle (MAS) or via direct activation of dehydrogenases of the TCA cycle after passing into the matrix through the mitochondrial Ca2+ uniporter (MCU). Another Ca2+-sensitive booster of mitochondrial ATP synthesis is the glycerol-3-phosphate shuttle (G3PS), whose role in neuronal energy supply has remained elusive. Essential components of G3PS are expressed in hippocampal neurons. Single neuron metabolic measurements in primary hippocampal cultures derived from rat pups of either sex reveal only moderate, if any, constitutive activity of G3PS. However, during electrical activity neurons fully rely on G3PS when MAS and MCU are unavailable. Under these conditions, G3PS is required for appropriate action potential firing. Accordingly, G3PS safeguards metabolic flexibility of neurons to cope with energy demands of electrical signaling.SIGNIFICANCE STATEMENT Ca2+ ions are known to provide a link between the energy-demanding electrical activity and an adequate ATP supply in neurons. To do so, Ca2+ acts both from outside and inside of the mitochondrial inner membrane. Neuronal function critically depends on this regulation, and its defects are often found in various neurologic disorders. Although interest in neuronal metabolism has increased, many aspects thereof have remained unresolved. In particular, a Ca2+-sensitive NADH (nicotinamide adenine dinucleotide) shuttling system, the glycerol-3-phosphate shuttle, has been largely ignored with respect to its function in neurons. Our results demonstrate that this shuttle is functional in hippocampal neurons and safeguards ATP supply and appropriate action potential firing when malate aspartate shuttle and mitochondrial Ca2+ uniporter are unavailable, thereby ensuring neuronal metabolic flexibility.
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Affiliation(s)
- Ankit Dhoundiyal
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Vanessa Goeschl
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Stefan Boehm
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Helmut Kubista
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Matej Hotka
- Center of Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, 1090 Vienna, Austria
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12
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Wang Y, Stancliffe E, Fowle-Grider R, Wang R, Wang C, Schwaiger-Haber M, Shriver LP, Patti GJ. Saturation of the mitochondrial NADH shuttles drives aerobic glycolysis in proliferating cells. Mol Cell 2022; 82:3270-3283.e9. [PMID: 35973426 PMCID: PMC10134440 DOI: 10.1016/j.molcel.2022.07.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 05/12/2022] [Accepted: 07/14/2022] [Indexed: 12/21/2022]
Abstract
Proliferating cells exhibit a metabolic phenotype known as "aerobic glycolysis," which is characterized by an elevated rate of glucose fermentation to lactate irrespective of oxygen availability. Although several theories have been proposed, a rationalization for why proliferating cells seemingly waste glucose carbon by excreting it as lactate remains elusive. Using the NCI-60 cell lines, we determined that lactate excretion is strongly correlated with the activity of mitochondrial NADH shuttles, but not proliferation. Quantifying the fluxes of the malate-aspartate shuttle (MAS), the glycerol 3-phosphate shuttle (G3PS), and lactate dehydrogenase under various conditions demonstrated that proliferating cells primarily transform glucose to lactate when glycolysis outpaces the mitochondrial NADH shuttles. Increasing mitochondrial NADH shuttle fluxes decreased glucose fermentation but did not reduce the proliferation rate. Our results reveal that glucose fermentation, a hallmark of cancer, is a secondary consequence of MAS and G3PS saturation rather than a unique metabolic driver of cellular proliferation.
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Affiliation(s)
- Yahui Wang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Ethan Stancliffe
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Ronald Fowle-Grider
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Rencheng Wang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Cheng Wang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Michaela Schwaiger-Haber
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Leah P Shriver
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gary J Patti
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130, USA; Siteman Cancer Center, Washington University in St. Louis, St. Louis, MO 63130, USA; Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, MO 63130, USA.
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13
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Pardo B, Herrada-Soler E, Satrústegui J, Contreras L, del Arco A. AGC1 Deficiency: Pathology and Molecular and Cellular Mechanisms of the Disease. Int J Mol Sci 2022; 23:528. [PMID: 35008954 PMCID: PMC8745132 DOI: 10.3390/ijms23010528] [Citation(s) in RCA: 4] [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: 11/22/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 02/01/2023] Open
Abstract
AGC1/Aralar/Slc25a12 is the mitochondrial carrier of aspartate-glutamate, the regulatory component of the NADH malate-aspartate shuttle (MAS) that transfers cytosolic redox power to neuronal mitochondria. The deficiency in AGC1/Aralar leads to the human rare disease named "early infantile epileptic encephalopathy 39" (EIEE 39, OMIM # 612949) characterized by epilepsy, hypotonia, arrested psychomotor neurodevelopment, hypo myelination and a drastic drop in brain aspartate (Asp) and N-acetylaspartate (NAA). Current evidence suggest that neurons are the main brain cell type expressing Aralar. However, paradoxically, glial functions such as myelin and Glutamine (Gln) synthesis are markedly impaired in AGC1 deficiency. Herein, we discuss the role of the AGC1/Aralar-MAS pathway in neuronal functions such as Asp and NAA synthesis, lactate use, respiration on glucose, glutamate (Glu) oxidation and other neurometabolic aspects. The possible mechanism triggering the pathophysiological findings in AGC1 deficiency, such as epilepsy and postnatal hypomyelination observed in humans and mice, are also included. Many of these mechanisms arise from findings in the aralar-KO mice model that extensively recapitulate the human disease including the astroglial failure to synthesize Gln and the dopamine (DA) mishandling in the nigrostriatal system. Epilepsy and DA mishandling are a direct consequence of the metabolic defect in neurons due to AGC1/Aralar deficiency. However, the deficits in myelin and Gln synthesis may be a consequence of neuronal affectation or a direct effect of AGC1/Aralar deficiency in glial cells. Further research is needed to clarify this question and delineate the transcellular metabolic fluxes that control brain functions. Finally, we discuss therapeutic approaches successfully used in AGC1-deficient patients and mice.
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Affiliation(s)
- Beatriz Pardo
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (E.H.-S.); (J.S.); (L.C.)
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain;
- Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Eduardo Herrada-Soler
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (E.H.-S.); (J.S.); (L.C.)
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain;
- Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (E.H.-S.); (J.S.); (L.C.)
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain;
- Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (E.H.-S.); (J.S.); (L.C.)
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain;
- Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Araceli del Arco
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-Consejo Superior de Investigaciones Científicas (CSIC), 28049 Madrid, Spain;
- Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Centro Regional de Investigaciones Biomédicas, Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla La Mancha, 45071 Toledo, Spain
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14
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de Moura Alvorcem L, Britto R, Cecatto C, Cristina Roginski A, Rohden F, Nathali Scholl J, Guma FCR, Figueiró F, Umpierrez Amaral A, Zanatta G, Seminotti B, Wajner M, Leipnitz G. Ethylmalonic acid impairs bioenergetics by disturbing succinate and glutamate oxidation and induces mitochondrial permeability transition pore opening in rat cerebellum. J Neurochem 2021; 158:262-281. [PMID: 33837559 DOI: 10.1111/jnc.15363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 03/04/2021] [Accepted: 04/06/2021] [Indexed: 12/01/2022]
Abstract
Tissue accumulation and high urinary excretion of ethylmalonic acid (EMA) are found in ethylmalonic encephalopathy (EE), an inherited disorder associated with cerebral and cerebellar atrophy whose pathogenesis is poorly established. The in vitro and in vivo effects of EMA on bioenergetics and redox homeostasis were investigated in rat cerebellum. For the in vitro studies, cerebellum preparations were exposed to EMA, whereas intracerebellar injection of EMA was used for the in vivo evaluation. EMA reduced state 3 and uncoupled respiration in vitro in succinate-, glutamate-, and malate-supported mitochondria, whereas decreased state 4 respiration was observed using glutamate and malate. Furthermore, mitochondria permeabilization and succinate supplementation diminished the decrease in state 3 with succinate. EMA also inhibited the activity of KGDH, an enzyme necessary for glutamate oxidation, in a mixed manner and augmented mitochondrial efflux of α-ketoglutarate. ATP levels were markedly reduced by EMA, reflecting a severe bioenergetic disruption. Docking simulations also indicated interactions between EMA and KGDH and a competition with glutamate and succinate for their mitochondrial transporters. In vitro findings also showed that EMA decreased mitochondrial membrane potential and Ca2+ retention capacity, and induced swelling in the presence of Ca2+ , which were prevented by cyclosporine A and ADP and ruthenium red, indicating mitochondrial permeability transition (MPT). Moreover, EMA, at high concentrations, mildly increased ROS levels and altered antioxidant defenses in vitro and in vivo. Our data indicate that EMA-induced impairment of glutamate and succinate oxidation and MPT may contribute to the pathogenesis of the cerebellum abnormalities in EE.
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Affiliation(s)
- Leonardo de Moura Alvorcem
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Renata Britto
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Cristiane Cecatto
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ana Cristina Roginski
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Francieli Rohden
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Juliete Nathali Scholl
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fátima C R Guma
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fabrício Figueiró
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Alexandre Umpierrez Amaral
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, RS, Brazil
| | - Geancarlo Zanatta
- Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - Bianca Seminotti
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Programa de Pós-Graduação em Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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15
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Han M, Zhang C, Suglo P, Sun S, Wang M, Su T. l-Aspartate: An Essential Metabolite for Plant Growth and Stress Acclimation. Molecules 2021; 26:molecules26071887. [PMID: 33810495 PMCID: PMC8037285 DOI: 10.3390/molecules26071887] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 01/07/2023] Open
Abstract
L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.
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Affiliation(s)
- Mei Han
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
| | - Can Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
| | - Peter Suglo
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
| | - Shuyue Sun
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
| | - Mingyao Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
| | - Tao Su
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China; (M.H.); (C.Z.); (P.S.); (S.S.); (M.W.)
- Key Laboratory of State Forestry Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing 210037, China
- Correspondence:
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16
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Xie N, Zhang L, Gao W, Huang C, Huber PE, Zhou X, Li C, Shen G, Zou B. NAD + metabolism: pathophysiologic mechanisms and therapeutic potential. Signal Transduct Target Ther 2020; 5:227. [PMID: 33028824 PMCID: PMC7539288 DOI: 10.1038/s41392-020-00311-7] [Citation(s) in RCA: 360] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/04/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) and its metabolites function as critical regulators to maintain physiologic processes, enabling the plastic cells to adapt to environmental changes including nutrient perturbation, genotoxic factors, circadian disorder, infection, inflammation and xenobiotics. These effects are mainly achieved by the driving effect of NAD+ on metabolic pathways as enzyme cofactors transferring hydrogen in oxidation-reduction reactions. Besides, multiple NAD+-dependent enzymes are involved in physiology either by post-synthesis chemical modification of DNA, RNA and proteins, or releasing second messenger cyclic ADP-ribose (cADPR) and NAADP+. Prolonged disequilibrium of NAD+ metabolism disturbs the physiological functions, resulting in diseases including metabolic diseases, cancer, aging and neurodegeneration disorder. In this review, we summarize recent advances in our understanding of the molecular mechanisms of NAD+-regulated physiological responses to stresses, the contribution of NAD+ deficiency to various diseases via manipulating cellular communication networks and the potential new avenues for therapeutic intervention.
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Affiliation(s)
- Na Xie
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Lu Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Wei Gao
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Canhua Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 611137, China
| | - Peter Ernst Huber
- CCU Molecular and Radiation Oncology, German Cancer Research Center; Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Xiaobo Zhou
- First Department of Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Changlong Li
- West China School of Basic Medical Sciences & Forensic Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Guobo Shen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China.
| | - Bingwen Zou
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China.
- CCU Molecular and Radiation Oncology, German Cancer Research Center; Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.
- Department of Thoracic Oncology and Department of Radiation Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
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17
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Abstract
T cells are an essential component of the immune system that provide antigen-specific acute and long lasting immune responses to infections and tumors, ascertain the maintenance of immunological tolerance and, on the flipside, mediate autoimmunity in a variety of diseases. The activation of T cells through antigen recognition by the T cell receptor (TCR) results in transient and sustained Ca2+ signals that are shaped by the opening of Ca2+ channels in the plasma membrane and cellular organelles. The dynamic regulation of intracellular Ca2+ concentrations controls a variety of T cell functions on the timescale of seconds to days after signal initiation. Among the more recently identified roles of Ca2+ signaling in T cells is the regulation of metabolic pathways that control the function of many T cell subsets. In this review, we discuss how Ca2+ regulates several metabolic programs in T cells such as the activation of AMPK and the PI3K-AKT-mTORC1 pathway, aerobic glycolysis, mitochondrial metabolism including tricarboxylic acid (TCA) cycle function and oxidative phosphorylation (OXPHOS), as well as lipid metabolism.
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Affiliation(s)
- Yinhu Wang
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Anthony Tao
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Martin Vaeth
- Institute of Systems Immunology, Julius Maximilians University of Würzburg, Würzburg, Germany
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY, USA
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18
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Borst P. The malate-aspartate shuttle (Borst cycle): How it started and developed into a major metabolic pathway. IUBMB Life 2020; 72:2241-2259. [PMID: 32916028 PMCID: PMC7693074 DOI: 10.1002/iub.2367] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022]
Abstract
This article presents a personal and critical review of the history of the malate–aspartate shuttle (MAS), starting in 1962 and ending in 2020. The MAS was initially proposed as a route for the oxidation of cytosolic NADH by the mitochondria in Ehrlich ascites cell tumor lacking other routes, and to explain the need for a mitochondrial aspartate aminotransferase (glutamate oxaloacetate transaminase 2 [GOT2]). The MAS was soon adopted in the field as a major pathway for NADH oxidation in mammalian tissues, such as liver and heart, even though the energetics of the MAS remained a mystery. Only in the 1970s, LaNoue and coworkers discovered that the efflux of aspartate from mitochondria, an essential step in the MAS, is dependent on the proton‐motive force generated by the respiratory chain: for every aspartate effluxed, mitochondria take up one glutamate and one proton. This makes the MAS in practice uni‐directional toward oxidation of cytosolic NADH, and explains why the free NADH/NAD ratio is much higher in the mitochondria than in the cytosol. The MAS is still a very active field of research. Most recently, the focus has been on the role of the MAS in tumors, on cells with defects in mitochondria and on inborn errors in the MAS. The year 2019 saw the discovery of two new inborn errors in the MAS, deficiencies in malate dehydrogenase 1 and in aspartate transaminase 2 (GOT2). This illustrates the vitality of ongoing MAS research.
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Affiliation(s)
- Piet Borst
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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19
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Szibor M, Gizatullina Z, Gainutdinov T, Endres T, Debska-Vielhaber G, Kunz M, Karavasili N, Hallmann K, Schreiber F, Bamberger A, Schwarzer M, Doenst T, Heinze HJ, Lessmann V, Vielhaber S, Kunz WS, Gellerich FN. Cytosolic, but not matrix, calcium is essential for adjustment of mitochondrial pyruvate supply. J Biol Chem 2020; 295:4383-4397. [PMID: 32094224 PMCID: PMC7135991 DOI: 10.1074/jbc.ra119.011902] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) and cellular workload are tightly balanced by the key cellular regulator, calcium (Ca2+). Current models assume that cytosolic Ca2+ regulates workload and that mitochondrial Ca2+ uptake precedes activation of matrix dehydrogenases, thereby matching OXPHOS substrate supply to ATP demand. Surprisingly, knockout (KO) of the mitochondrial Ca2+ uniporter (MCU) in mice results in only minimal phenotypic changes and does not alter OXPHOS. This implies that adaptive activation of mitochondrial dehydrogenases by intramitochondrial Ca2+ cannot be the exclusive mechanism for OXPHOS control. We hypothesized that cytosolic Ca2+, but not mitochondrial matrix Ca2+, may adapt OXPHOS to workload by adjusting the rate of pyruvate supply from the cytosol to the mitochondria. Here, we studied the role of malate-aspartate shuttle (MAS)-dependent substrate supply in OXPHOS responses to changing Ca2+ concentrations in isolated brain and heart mitochondria, synaptosomes, fibroblasts, and thymocytes from WT and MCU KO mice and the isolated working rat heart. Our results indicate that extramitochondrial Ca2+ controls up to 85% of maximal pyruvate-driven OXPHOS rates, mediated by the activity of the complete MAS, and that intramitochondrial Ca2+ accounts for the remaining 15%. Of note, the complete MAS, as applied here, included besides its classical NADH oxidation reaction the generation of cytosolic pyruvate. Part of this largely neglected mechanism has previously been described as the “mitochondrial gas pedal.” Its implementation into OXPHOS control models integrates seemingly contradictory results and warrants a critical reappraisal of metabolic control mechanisms in health and disease.
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Affiliation(s)
- Marten Szibor
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland.,Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Zemfira Gizatullina
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany
| | - Timur Gainutdinov
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany.,Research Institute for Problems of Ecology and Mineral Wealth Use, Tatarstan Academy of Sciences, Kazan 420087, Russia
| | - Thomas Endres
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland
| | | | - Matthias Kunz
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany
| | - Niki Karavasili
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany
| | - Kerstin Hallmann
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Frank Schreiber
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany
| | - Alexandra Bamberger
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Michael Schwarzer
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Torsten Doenst
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Hans-Jochen Heinze
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), D-39120 Magdeburg, Germany
| | - Volkmar Lessmann
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland.,Center for Behavioral Brain Sciences (CBBS), D-39120 Magdeburg, Germany
| | - Stefan Vielhaber
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany.,German Center for Neurodegenerative Diseases, D-39120 Magdeburg, Germany
| | - Wolfram S Kunz
- Department of Cardiothoracic Surgery, Jena University Hospital, D-07747 Jena, Germany
| | - Frank N Gellerich
- Department of Neurology, Otto-von-Guericke-University, D-39120 Magdeburg, Germany .,Leibniz-Institute for Neurobiology, D-39120 Magdeburg, Germany
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20
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Liu Y, Liu XM, Bi J, Yu S, Yang N, Song B, Chen X. Cell migration and osteo/odontogenesis stimulation of iRoot FS as a potential apical barrier material in apexification. Int Endod J 2019; 53:467-477. [PMID: 31622505 DOI: 10.1111/iej.13237] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 10/06/2019] [Accepted: 10/14/2019] [Indexed: 12/11/2022]
Abstract
AIM To investigate the in vitro biological effects of a nanoparticle bioceramic material, iRoot Fast Set root repair material (iRoot FS), on the proliferation, migration and osteo/odontogenic differentiation of human stem cells from the apical papilla (hSCAP), and to further explore the mechanism involved in osteo/odontogenic induction of iRoot FS. METHODOLOGY hSCAP were isolated and characterized in vitro. iRoot FS conditioned medium were prepared and used to treat hSCAP, while using mineral trioxide aggregate (MTA) conditioned medium as the positive control and regular medium as the negative control. MTT assay and BrdU labelling assay were performed to determine cell proliferation. Wound healing assay and transwell assay were conducted to evaluate cell migration. The osteo/odontogenic differentiation of hSCAP was evaluated by qPCR, Western blot and Alizarin red S staining. Wnt inhibitor was used for downregulating the expression level of β-catenin of hSCAP. RESULTS The cell proliferation of hSACP in the iRoot FS group was not significantly different compared with the control groups. The cell migration of hSCAP in the iRoot FS group was significantly increased than the MTA and negative control groups (P < 0.01). The expression levels of osteo/odontogenic markers and mineralization nodule formation of hSCAP in the iRoot FS group were significantly elevated (P < 0.01). Furthermore, iRoot FS enhanced the osteo/odontogenic differentiation of hSCAP by activating Wnt/β-catenin signalling. CONCLUSIONS iRoot FS promoted the cell migration of hSCAP and enhanced their oseto/odontogenesis potential via the Wnt/β-catenin pathway without cytotoxicity. iRoot FS had satisfactory biological properties and has potential to be used as an apical barrier in apexification or as a coronal sealing material in regenerative endodontic treatment.
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Affiliation(s)
- Y Liu
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
| | - X M Liu
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
| | - J Bi
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
| | - S Yu
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
| | - N Yang
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
| | - B Song
- School of Dentistry, Cardiff University, Cardiff, UK
| | - X Chen
- Department of Paediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China.,Liaoning Province Key Laboratory of Oral Disease, Shenyang, China
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21
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Wen M, Jin Y, Zhang H, Sun X, Kuai Y, Tan W. Proteomic Analysis of Rat Cerebral Cortex in the Subacute to Long-Term Phases of Focal Cerebral Ischemia-Reperfusion Injury. J Proteome Res 2019; 18:3099-3118. [PMID: 31265301 DOI: 10.1021/acs.jproteome.9b00220] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Stroke is a leading cause of mortality and disability, and ischemic stroke accounts for more than 80% of the disease occurrence. Timely reperfusion is essential in the treatment of ischemic stroke, but it is known to cause ischemia-reperfusion (I/R) injury and the relevant studies have mostly focused on the acute phase. Here we reported on a global proteomic analysis to investigate the development of cerebral I/R injury in the subacute and long-term phases. A rat model was used, with 2 h-middle cerebral artery occlusion (MCAO) followed with 1, 7, and 14 days of reperfusion. The proteins of cerebral cortex were analyzed by SDS-PAGE, whole-gel slicing, and quantitative LC-MS/MS. Totally 5621 proteins were identified, among which 568, 755, and 492 proteins were detected to have significant dys-regulation in the model groups with 1, 7, and 14 days of reperfusion, respectively, when compared with the corresponding sham groups (n = 4, fold change ≥1.5 or ≤0.67 and p ≤ 0.05). Bioinformatic analysis on the functions and reperfusion time-dependent dys-regulation profiles of the proteins exhibited changes of structures and biological processes in cytoskeleton, synaptic plasticity, energy metabolism, inflammation, and lysosome from subacute to long-term phases of cerebral I/R injury. Disruption of cytoskeleton and synaptic structures, impairment of energy metabolism processes, and acute inflammation responses were the most significant features in the subacute phase. With the elongation of reperfusion time to the long-term phase, a tendency of recovery was detected on cytoskeleton, while inflammation pathways different from the subacute phase were activated. Also, lysosomal structures and functions might be restored. This is the first work reporting the proteome changes that occurred at different time points from the subacute to long-term phases of cerebral I/R injury and we expect it would provide useful information to improve the understanding of the mechanisms involved in the development of cerebral I/R injury and suggest candidates for treatment.
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Affiliation(s)
- Meiling Wen
- School of Biology and Biological Engineering , South China University of Technology , Guangzhou 510006 , P. R. China
| | - Ya Jin
- Institute of Biomedical and Pharmaceutical Sciences , Guangdong University of Technology , Guangzhou 510006 , P. R. China
| | - Hao Zhang
- Institute of Biomedical and Pharmaceutical Sciences , Guangdong University of Technology , Guangzhou 510006 , P. R. China
| | - Xiaoou Sun
- Institute of Biomedical and Pharmaceutical Sciences , Guangdong University of Technology , Guangzhou 510006 , P. R. China
| | - Yihe Kuai
- Institute of Biomedical and Pharmaceutical Sciences , Guangdong University of Technology , Guangzhou 510006 , P. R. China
| | - Wen Tan
- Institute of Biomedical and Pharmaceutical Sciences , Guangdong University of Technology , Guangzhou 510006 , P. R. China
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22
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Distinct modes of mitochondrial metabolism uncouple T cell differentiation and function. Nature 2019; 571:403-407. [PMID: 31217581 DOI: 10.1038/s41586-019-1311-3] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 05/22/2019] [Indexed: 12/25/2022]
Abstract
Activated CD4 T cells proliferate rapidly and remodel epigenetically before exiting the cell cycle and engaging acquired effector functions. Metabolic reprogramming from the naive state is required throughout these phases of activation1. In CD4 T cells, T-cell-receptor ligation-along with co-stimulatory and cytokine signals-induces a glycolytic anabolic program that is required for biomass generation, rapid proliferation and effector function2. CD4 T cell differentiation (proliferation and epigenetic remodelling) and function are orchestrated coordinately by signal transduction and transcriptional remodelling. However, it remains unclear whether these processes are regulated independently of one another by cellular biochemical composition. Here we demonstrate that distinct modes of mitochondrial metabolism support differentiation and effector functions of mouse T helper 1 (TH1) cells by biochemically uncoupling these two processes. We find that the tricarboxylic acid cycle is required for the terminal effector function of TH1 cells through succinate dehydrogenase (complex II), but that the activity of succinate dehydrogenase suppresses TH1 cell proliferation and histone acetylation. By contrast, we show that complex I of the electron transport chain, the malate-aspartate shuttle and mitochondrial citrate export are required to maintain synthesis of aspartate, which is necessary for the proliferation of T helper cells. Furthermore, we find that mitochondrial citrate export and the malate-aspartate shuttle promote histone acetylation, and specifically regulate the expression of genes involved in T cell activation. Combining genetic, pharmacological and metabolomics approaches, we demonstrate that the differentiation and terminal effector functions of T helper cells are biochemically uncoupled. These findings support a model in which the malate-aspartate shuttle, mitochondrial citrate export and complex I supply the substrates needed for proliferation and epigenetic remodelling early during T cell activation, whereas complex II consumes the substrates of these pathways, which antagonizes differentiation and enforces terminal effector function. Our data suggest that transcriptional programming acts together with a parallel biochemical network to enforce cell state.
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23
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Bugaj O, Zieliński J, Kusy K, Kantanista A, Wieliński D, Guzik P. The Effect of Exercise on the Skin Content of the Reduced Form of NAD and Its Response to Transient Ischemia and Reperfusion in Highly Trained Athletes. Front Physiol 2019; 10:600. [PMID: 31156467 PMCID: PMC6529559 DOI: 10.3389/fphys.2019.00600] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/26/2019] [Indexed: 12/22/2022] Open
Abstract
Reduced nicotinamide adenine dinucleotide (NADH) is synthesized in the cellular nucleus, cytoplasm and mitochondria but oxidized into NAD+ almost exclusively in mitochondria. Activation of human skin by the 340 nm ultraviolet light triggers natural fluorescence at the light length of 460 nm, which intensity is proportional to the skin NADH content. This phenomenon is used by the Flow Mediated Skin Fluorescence (FMSF) which measures changes in the skin NADH content during transient ischemia and reperfusion. We examined the effects of exercise to exhaustion on the skin changes of NADH in response to 200 s forearm ischemia and reperfusion in 121 highly trained athletes (94 men and 27 women, long-distance running, triathlon, taekwondo, rowing, futsal, sprint running, fencing, and tennis). We found that exercise until exhaustion changes the skin content of NADH, modifies NADH turnover at rest, during ischemia and reperfusion in the most superficial living skin cells. Compared to the pre-exercise, there were significant increases in: mean fluorescence recorded during rest as the baseline value (B mean) (p < 0.001), the maximal fluorescence that increased above the baseline during controlled forearm ischemia (FImax) (p < 0.001, only in men), the minimal fluorescence after decreasing below the baseline during reperfusion (FRmin) (p < 0.001 men; p < 0.01 women) and the difference between B mean and FRmin (R min) (p < 0.01), and reductions in the difference between FImax and B mean (I max) (p < 0.001) and I max/IRampl ratio (CImax) (p < 0.001) after the incremental exercise test. There was no statistical difference between pre- and post-exercise the maximal range of the fluorescence change during ischemia and reperfusion (IRampl). In conclusion, exercise to exhaustion modifies the skin NADH content at rest, during ischemia and reperfusion as well as the magnitude of changes in the NADH caused by ischemia and reperfusion. Our findings suggest that metabolic changes in the skin NADH accompanying exercise extend beyond muscles and affect other cells and organs.
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Affiliation(s)
- Olga Bugaj
- Department of Athletics, Strength and Conditioning, Poznań University of Physical Education, Poznań, Poland
| | - Jacek Zieliński
- Department of Athletics, Strength and Conditioning, Poznań University of Physical Education, Poznań, Poland
| | - Krzysztof Kusy
- Department of Athletics, Strength and Conditioning, Poznań University of Physical Education, Poznań, Poland
| | - Adam Kantanista
- Department of Sport Kinesiology, Poznań University of Physical Education, Poznań, Poland
| | - Dariusz Wieliński
- Department of Anthropology and Biometry, Poznań University of Physical Education, Poznań, Poland
| | - Przemysław Guzik
- Department of Cardiology-Intensive Therapy, Poznań University of Medical Sciences, Poznań, Poland
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24
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Juaristi I, Contreras L, González-Sánchez P, Pérez-Liébana I, González-Moreno L, Pardo B, Del Arco A, Satrústegui J. The Response to Stimulation in Neurons and Astrocytes. Neurochem Res 2019; 44:2385-2391. [PMID: 31016552 DOI: 10.1007/s11064-019-02803-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 12/19/2022]
Abstract
The brain uses mainly glucose as fuel with an index of glucose to oxygen utilization close to 6, the maximal index if all glucose was completely oxidized. However, this high oxidative index, contrasts with the metabolic traits of the major cell types in the brain studied in culture, neurons and astrocytes, including the selective use of the malate-aspartate shuttle (MAS) in neurons and the glycerol-phosphate shuttle in astrocytes. Metabolic interactions among these cell types may partly explain the high oxidative index of the brain. In vivo, neuronal activation results in a decrease in the oxygen glucose index, which has been attributed to a stimulation of glycolysis and lactate production in astrocytes in response to glutamate uptake (astrocyte-neuron lactate shuttle, ANLS). Recent findings indicate that this is accompanied with a stimulation of pyruvate formation and astrocyte respiration, indicating that lactate formation is not the only astrocytic response to neuronal activation. ANLS proposes that neurons utilize lactate produced by neighboring astrocytes. Indeed, neurons can use lactate to support an increase in respiration with different workloads, and this depends on the Ca2+ activation of MAS. However, whether this activation operates in the brain, particularly at high stimulation conditions, remains to be established.
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Affiliation(s)
- Inés Juaristi
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Paloma González-Sánchez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Irene Pérez-Liébana
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Luis González-Moreno
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Araceli Del Arco
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
- Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla la Mancha, Toledo, Spain
- Centro Regional de Investigaciones Biomédicas, Unidad Asociada de Biomedicina UCLM-CSIC, Toledo, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Nicolás Cabrera, 1, 28049, Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
- Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain.
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25
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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Egnatchik RA, Leamy AK, Sacco SA, Cheah YE, Shiota M, Young JD. Glutamate-oxaloacetate transaminase activity promotes palmitate lipotoxicity in rat hepatocytes by enhancing anaplerosis and citric acid cycle flux. J Biol Chem 2018; 294:3081-3090. [PMID: 30563841 DOI: 10.1074/jbc.ra118.004869] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/04/2018] [Indexed: 12/17/2022] Open
Abstract
Hepatocyte lipotoxicity is characterized by aberrant mitochondrial metabolism, which predisposes cells to oxidative stress and apoptosis. Previously, we reported that translocation of calcium from the endoplasmic reticulum to mitochondria of palmitate-treated hepatocytes activates anaplerotic flux from glutamine to α-ketoglutarate (αKG), which subsequently enters the citric acid cycle (CAC) for oxidation. We hypothesized that increased glutamine anaplerosis fuels elevations in CAC flux and oxidative stress following palmitate treatment. To test this hypothesis, primary rat hepatocytes or immortalized H4IIEC3 rat hepatoma cells were treated with lipotoxic levels of palmitate while modulating anaplerotic pathways leading to αKG. We found that culture media supplemented with glutamine, glutamate, or dimethyl-αKG increased palmitate lipotoxicity compared with media that lacked these anaplerotic substrates. Knockdown of glutamate-oxaloacetate transaminase activity significantly reduced the lipotoxic effects of palmitate, whereas knockdown of glutamate dehydrogenase (Glud1) had no effect on palmitate lipotoxicity. 13C flux analysis of H4IIEC3 cells co-treated with palmitate and the pan-transaminase inhibitor aminooxyacetic acid confirmed that reductions in lipotoxic markers were associated with decreases in anaplerosis, CAC flux, and oxygen consumption. Taken together, these results demonstrate that lipotoxic palmitate treatments enhance anaplerosis in cultured rat hepatocytes, causing a shift to aberrant transaminase metabolism that fuels CAC dysregulation and oxidative stress.
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Affiliation(s)
| | | | | | | | - Masakazu Shiota
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37235
| | - Jamey D Young
- From Chemical and Biomolecular Engineering and .,Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37235
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27
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Nutritional Regulators of Bcl-xL in the Brain. Molecules 2018; 23:molecules23113019. [PMID: 30463183 PMCID: PMC6278276 DOI: 10.3390/molecules23113019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/15/2018] [Accepted: 11/18/2018] [Indexed: 01/12/2023] Open
Abstract
B-cell lymphoma-extra large (Bcl-xL) is an anti-apoptotic Bcl-2 protein found in the mitochondrial membrane. Bcl-xL is reported to support normal brain development and protects neurons against toxic stimulation during pathological process via its roles in regulation of mitochondrial functions. Despite promising evidence showing neuroprotective properties of Bcl-xL, commonly applied molecular approaches such as genetic manipulation may not be readily applicable for human subjects. Therefore, findings at the bench may be slow to be translated into treatments for disease. Currently, there is no FDA approved application that specifically targets Bcl-xL and treats brain-associated pathology in humans. In this review, we will discuss naturally occurring nutrients that may exhibit regulatory effects on Bcl-xL expression or activity, thus potentially providing affordable, readily-applicable, easy, and safe strategies to protect the brain.
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28
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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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Wang T, Yao W, Li J, He Q, Shao Y, Huang F. Acetyl-CoA from inflammation-induced fatty acids oxidation promotes hepatic malate-aspartate shuttle activity and glycolysis. Am J Physiol Endocrinol Metab 2018; 315:E496-E510. [PMID: 29763372 DOI: 10.1152/ajpendo.00061.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hepatic metabolic syndrome is associated with inflammation, as inflammation stimulates the reprogramming of nutrient metabolism and hepatic mitochondria-generated acetyl-CoA, but how acetyl-CoA affects the reprogramming of nutrient metabolism, especially glucose and fatty acids, in the condition of inflammation is still unclear. Here, we used an acute inflammation model in which pigs were injected with lipopolysaccharide (LPS) and found that hepatic glycolysis and fatty acid oxidation are both promoted. Acetyl-proteome profiling of LPS-infected pigs liver showed that inflammatory stress exacerbates the acetylation of mitochondrial proteins. Both mitochondrial glutamate oxaloacetate transaminase 2 (GOT2) and malate dehydrogenase 2 (MDH2) were acetylated, and the malate-aspartate shuttle (MAS) activity was stimulated to maintain glycolysis. With the use of 13C-carbon tracing in vitro, acetyl-CoA was found to be mainly supplied by lipid-derived fatty acid oxidation rather than glucose-derived pyruvate oxidative decarboxylation, while glucose was mainly used for lactate production in response to inflammatory stress. The results of the mitochondrial experiment showed that acetyl-CoA directly increases MDH2 and, in turn, the GOT2 acetylation level affects MAS activity. Treatment with palmitate in primary hepatocytes from LPS-injected pigs increased the hepatic production of acetyl-CoA, pyruvate, and lactate; MAS activity; and hepatic MDH2 and GOT2 hyperacetylation, while the deficiency of long-chain acetyl-CoA dehydrogenase resulted in the stabilization of these parameters. These observations suggest that acetyl-CoA produced by fatty acid oxidation promotes MAS activity and glycolysis via nonenzymatic acetylation during the inflammatory stress response.
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Affiliation(s)
- Tongxin Wang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Weilei Yao
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Ji Li
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Qiongyu He
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Yafei Shao
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Feiruo Huang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University , Wuhan , China
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Bak LK, Walls AB. CrossTalk opposing view: lack of evidence supporting an astrocyte-to-neuron lactate shuttle coupling neuronal activity to glucose utilisation in the brain. J Physiol 2018; 596:351-353. [PMID: 29292507 DOI: 10.1113/jp274945] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Affiliation(s)
- Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Anne B Walls
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
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31
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Sun Y, Luo T, Shen Y, Haapasalo M, Zou L, Liu J. Effect of iRoot Fast Set root repair material on the proliferation, migration and differentiation of human dental pulp stem cells in vitro. PLoS One 2017; 12:e0186848. [PMID: 29059236 PMCID: PMC5653327 DOI: 10.1371/journal.pone.0186848] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 10/09/2017] [Indexed: 02/06/2023] Open
Abstract
The present study investigated the effect of iRoot Fast Set root repair material (iRoot FS) on the proliferation, migration and differentiation of human dental pulp stem cells (hDPSCs). The hDPSCs were treated with eluates of iRoot FS at concentrations of 0.2 and 2 mg/mL, referred to as FS0.2 and FS2, respectively, and Biodentine (BD; Septodont, Saint Maur des Faussés, France) eluates at the corresponding concentrations as positive controls. A CCK8 assay was performed to determine cell proliferation. Wound healing and transwell assays were conducted to examine cell migration. Osteogenic differentiation was evaluated based on alkaline phosphatase activity, Alizarin Red S staining and quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR) to analyze the mRNA expression of differentiation gene markers. Cell proliferation was higher in the FS and BD groups than in the blank controls at 3 and 7 days. Moreover, FS0.2 enhanced cell migration and significantly promoted the osteogenic differentiation of hDPSCs. These findings suggested that iRoot FS is a bioactive material that promotes the proliferation, migration and osteogenic differentiation of hDPSCs.
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Affiliation(s)
- Yan Sun
- State Key Laboratory of Oral Diseases, Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Tao Luo
- State Key Laboratory of Oral Diseases, Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Markus Haapasalo
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ling Zou
- State Key Laboratory of Oral Diseases, Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- * E-mail: (JL); ) (LZ)
| | - Jun Liu
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- * E-mail: (JL); ) (LZ)
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Juaristi I, García-Martín ML, Rodrigues TB, Satrústegui J, Llorente-Folch I, Pardo B. ARALAR/AGC1 deficiency, a neurodevelopmental disorder with severe impairment of neuronal mitochondrial respiration, does not produce a primary increase in brain lactate. J Neurochem 2017; 142:132-139. [PMID: 28429368 DOI: 10.1111/jnc.14047] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 03/07/2017] [Accepted: 04/07/2017] [Indexed: 12/28/2022]
Abstract
ARALAR/AGC1 (aspartate-glutamate mitochondrial carrier 1) is an important component of the NADH malate-aspartate shuttle (MAS). AGC1-deficiency is a rare disease causing global cerebral hypomyelination, developmental arrest, hypotonia, and epilepsy (OMIM ID #612949); the aralar-KO mouse recapitulates the major findings in humans. This study was aimed at understanding the impact of ARALAR-deficiency in brain lactate levels as a biomarker. We report that lactate was equally abundant in wild-type and aralar-KO mouse brain in vivo at postnatal day 17. We find that lactate production upon mitochondrial blockade depends on up-regulation of lactate formation in astrocytes rather than in neurons. However, ARALAR-deficiency decreased cell respiration in neurons, not astrocytes, which maintained unchanged respiration and lactate production. As the primary site of ARALAR-deficiency is neuronal, this explains the lack of accumulation of brain lactate in ARALAR-deficiency in humans and mice. On the other hand, we find that the cytosolic and mitochondrial components of the glycerol phosphate shuttle are present in astrocytes with similar activities. This suggests that glycerol phosphate shuttle is the main NADH shuttle in astrocytes and explains the absence of effects of ARALAR-deficiency in these cells.
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Affiliation(s)
- Inés Juaristi
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.,CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD); Universidad Autónoma de Madrid, Madrid, Spain
| | - María L García-Martín
- Laboratory of Metabolomics and Molecular Imaging, BIONAND, Andalusian Centre for Nanomedicine and Biotechnology (Junta de Andalucía, Universidad de Málaga), Malaga, Spain
| | - Tiago B Rodrigues
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.,Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.,CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD); Universidad Autónoma de Madrid, Madrid, Spain
| | - Irene Llorente-Folch
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.,CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD); Universidad Autónoma de Madrid, Madrid, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain.,CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD); Universidad Autónoma de Madrid, Madrid, Spain
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Contreras L, Ramirez L, Du J, Hurley JB, Satrústegui J, de la Villa P. Deficient glucose and glutamine metabolism in Aralar/AGC1/Slc25a12 knockout mice contributes to altered visual function. Mol Vis 2016; 22:1198-1212. [PMID: 27746674 PMCID: PMC5063090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 10/10/2016] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To characterize the vision phenotype of mice lacking Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier mutated in global cerebral hypomyelination (OMIM 612949). METHODS We tested overnight dark-adapted control and aralar-deficient mice for the standard full electroretinogram (ERG) response. The metabolic stress of dark-adaptation was reduced by 5 min illumination after which the ERG response was monitored in darkness. We used the electrical response to two identical saturating light flashes (paired-flash stimulation) to isolate the inner retina and photoreceptor responses. Retinal morphology was examined with hematoxylin and eosin staining, immunohistochemistry of antibodies against retinal cells, and 4',6-diamidino-2-phenylindole (DAPI) labeling. RESULTS Aralar plays a pivotal role in retina metabolism as aralar provides de novo synthesis pathway for glutamine, protects glutamate from oxidation, and is required for efficient glucose oxidative metabolism. Aralar-deficient mice are not blind as their retinas have light-evoked activity. However, we report an approximate 50% decrease in the ERG amplitude response in the light-evoked activity of dark-adapted retinas from aralar-deficient mice, in spite of normal retina histology. The defective response is partly reversed by exposure to a brief illumination period, which lowers the metabolic stress of dark-adaptation. The metabolic stress and ERG alteration takes place primarily in photoreceptors, but the response to two flashes applied in fast succession also revealed an alteration in synaptic transmission consistent with an imbalance of glutamate and an energy deficit in the inner retina neurons. CONCLUSIONS We propose that compromised glucose oxidation and altered glutamine and glutamate metabolism in the absence of aralar are responsible for the phenotype reported.
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Affiliation(s)
- Laura Contreras
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, CI.B.E.R. de Enfermedades Raras, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Ramirez
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
| | - Jianhai Du
- Department of Biochemistry, University of Washington, Seattle, WA.,Department of Ophthalmology, University of Washington, Seattle, WA
| | - James B. Hurley
- Department of Biochemistry, University of Washington, Seattle, WA.,Department of Ophthalmology, University of Washington, Seattle, WA
| | - Jorgina Satrústegui
- Centro de Biología Molecular Severo Ochoa CSIC-UAM, CI.B.E.R. de Enfermedades Raras, Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid, Spain
| | - Pedro de la Villa
- Department of Systems Biology, University of Alcalá, Alcalá de Henares, Spain
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L-Lactate-Mediated Neuroprotection against Glutamate-Induced Excitotoxicity Requires ARALAR/AGC1. J Neurosci 2016; 36:4443-56. [PMID: 27098689 DOI: 10.1523/jneurosci.3691-15.2016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/20/2016] [Indexed: 01/20/2023] Open
Abstract
UNLABELLED ARALAR/AGC1/Slc25a12, the aspartate-glutamate carrier from brain mitochondria, is the regulatory step in the malate-aspartate NADH shuttle, MAS. MAS is used to oxidize cytosolic NADH in mitochondria, a process required to maintain oxidative glucose utilization. The role of ARALAR was analyzed in two paradigms of glutamate-induced excitotoxicity in cortical neurons: glucose deprivation and acute glutamate stimulation. ARALAR deficiency did not aggravate glutamate-induced neuronal death in vitro, although glutamate-stimulated respiration was impaired. In contrast, the presence of L-lactate as an additional source protected against glutamate-induced neuronal death in control, but not ARALAR-deficient neurons.l-Lactate supplementation increased glutamate-stimulated respiration partially prevented the decrease in the cytosolic ATP/ADP ratio induced by glutamate and substantially diminished mitochondrial accumulation of 8-oxoguanosine, a marker of reactive oxygen species production, only in the presence, but not the absence, of ARALAR. In addition,l-lactate potentiated glutamate-induced increase in cytosolic Ca(2+), in a way independent of the presence of ARALAR. Interestingly,in vivo, the loss of half-a-dose of ARALAR in aralar(+/-)mice enhanced kainic acid-induced seizures and neuronal damage with respect to control animals, in a model of excitotoxicity in which increased L-lactate levels and L-lactate consumption have been previously proven. These results suggest that,in vivo, an inefficient operation of the shuttle in the aralar hemizygous mice prevents the protective role of L-lactate on glutamate excitotoxiciy and that the entry and oxidation of L-lactate through ARALAR-MAS pathway is required for its neuroprotective function. SIGNIFICANCE STATEMENT Lactate now stands as a metabolite necessary for multiple functions in the brain and is an alternative energy source during excitotoxic brain injury. Here we find that the absence of a functional malate-aspartate NADH shuttle caused by aralar/AGC1 disruption causes a block in lactate utilization by neurons, which prevents the protective role of lactate on excitotoxicity, but not glutamate excitotoxicity itself. Thus, failure to use lactate is detrimental and is possibly responsible for the exacerbated in vivo excitotoxicity in aralar(+/-)mice.
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35
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Proia P, Di Liegro CM, Schiera G, Fricano A, Di Liegro I. Lactate as a Metabolite and a Regulator in the Central Nervous System. Int J Mol Sci 2016; 17:E1450. [PMID: 27598136 PMCID: PMC5037729 DOI: 10.3390/ijms17091450] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 12/21/2022] Open
Abstract
More than two hundred years after its discovery, lactate still remains an intriguing molecule. Considered for a long time as a waste product of metabolism and the culprit behind muscular fatigue, it was then recognized as an important fuel for many cells. In particular, in the nervous system, it has been proposed that lactate, released by astrocytes in response to neuronal activation, is taken up by neurons, oxidized to pyruvate and used for synthesizing acetyl-CoA to be used for the tricarboxylic acid cycle. More recently, in addition to this metabolic role, the discovery of a specific receptor prompted a reconsideration of its role, and lactate is now seen as a sort of hormone, even involved in processes as complex as memory formation and neuroprotection. As a matter of fact, exercise offers many benefits for our organisms, and seems to delay brain aging and neurodegeneration. Now, exercise induces the production and release of lactate into the blood which can reach the liver, the heart, and also the brain. Can lactate be a beneficial molecule produced during exercise, and offer neuroprotection? In this review, we summarize what we have known on lactate, discussing the roles that have been attributed to this molecule over time.
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Affiliation(s)
- Patrizia Proia
- Department of Psychological, Pedagogical and Educational Sciences, Sport and Exercise Sciences Research Unit, University of Palermo, Palermo I-90128, Italy.
| | - Carlo Maria Di Liegro
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Gabriella Schiera
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Anna Fricano
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Italia Di Liegro
- Department of Experimental Biomedicine and Clinical Neurosciences (BIONEC), University of Palermo, Palermo I-90127, Italy.
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36
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Herbst EA, Holloway GP. Exercise increases mitochondrial glutamate oxidation in the mouse cerebral cortex. Appl Physiol Nutr Metab 2016; 41:799-801. [DOI: 10.1139/apnm-2016-0033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study investigated the impact of acute exercise on stimulating mitochondrial respiratory function in mouse cerebral cortex. Where pyruvate-stimulated respiration was not affected by acute exercise, glutamate respiration was enhanced following the exercise bout. Additional assessment revealed that this affect was dependent on the presence of malate and did not occur when substituting glutamine for glutamate. As such, our results suggest that glutamate oxidation is enhanced with acute exercise through activation of the malate–aspartate shuttle.
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Affiliation(s)
- Eric A.F. Herbst
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Graham P. Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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37
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Dienel GA, Cruz NF. Aerobic glycolysis during brain activation: adrenergic regulation and influence of norepinephrine on astrocytic metabolism. J Neurochem 2016; 138:14-52. [DOI: 10.1111/jnc.13630] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/24/2016] [Accepted: 03/31/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Gerald A. Dienel
- Department of Cell Biology and Physiology; University of New Mexico; Albuquerque; New Mexico USA
- Department of Neurology; University of Arkansas for Medical Sciences; Little Rock Arkansas USA
| | - Nancy F. Cruz
- Department of Neurology; University of Arkansas for Medical Sciences; Little Rock Arkansas USA
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38
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Amoedo ND, Punzi G, Obre E, Lacombe D, De Grassi A, Pierri CL, Rossignol R. AGC1/2, the mitochondrial aspartate-glutamate carriers. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2394-412. [PMID: 27132995 DOI: 10.1016/j.bbamcr.2016.04.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/28/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
Abstract
In this review we discuss the structure and functions of the aspartate/glutamate carriers (AGC1-aralar and AGC2-citrin). Those proteins supply the aspartate synthesized within mitochondrial matrix to the cytosol in exchange for glutamate and a proton. A structure of an AGC carrier is not available yet but comparative 3D models were proposed. Moreover, transport assays performed by using the recombinant AGC1 and AGC2, reconstituted into liposome vesicles, allowed to explore the kinetics of those carriers and to reveal their specific transport properties. AGCs participate to a wide range of cellular functions, as the control of mitochondrial respiration, calcium signaling and antioxydant defenses. AGC1 might also play peculiar tissue-specific functions, as it was found to participate to cell-to-cell metabolic symbiosis in the retina. On the other hand, AGC1 is involved in the glutamate-mediated excitotoxicity in neurons and AGC gene or protein alterations were discovered in rare human diseases. Accordingly, a mice model of AGC1 gene knock-out presented with growth delay and generalized tremor, with myelinisation defects. More recently, AGC was proposed to play a crucial role in tumor metabolism as observed from metabolomic studies showing that the asparate exported from the mitochondrion by AGC1 is employed in the regeneration of cytosolic glutathione. Therefore, given the central role of AGCs in cell metabolism and human pathology, drug screening are now being developed to identify pharmacological modulators of those carriers. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- N D Amoedo
- Univ. Bordeaux, U1211, Bordeaux, France; INSERM, U1211, Bordeaux, France; Instituto de Bioquímica Médica Leopoldo De Meis, UFRJ, Rio de Janeiro, Brazil
| | - G Punzi
- Univ. Bordeaux, U1211, Bordeaux, France; INSERM, U1211, Bordeaux, France; Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari
| | - E Obre
- Univ. Bordeaux, U1211, Bordeaux, France; INSERM, U1211, Bordeaux, France
| | - D Lacombe
- Univ. Bordeaux, U1211, Bordeaux, France; INSERM, U1211, Bordeaux, France
| | - A De Grassi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari
| | - C L Pierri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari.
| | - R Rossignol
- Univ. Bordeaux, U1211, Bordeaux, France; INSERM, U1211, Bordeaux, France.
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39
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Del Arco A, Contreras L, Pardo B, Satrustegui J. Calcium regulation of mitochondrial carriers. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2413-21. [PMID: 27033520 DOI: 10.1016/j.bbamcr.2016.03.024] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/23/2016] [Accepted: 03/23/2016] [Indexed: 11/16/2022]
Abstract
Mitochondrial function is regulated by calcium. In addition to the long known effects of matrix Ca(2+), regulation of metabolite transport by extramitochondrial Ca(2+) represents an alternative Ca(2+)-dependent mechanism to regulate mitochondrial function. The Ca(2+) regulated mitochondrial transporters (CaMCs) are well suited for that role, as they contain long N-terminal extensions harboring EF-hand Ca(2+) binding domains facing the intermembrane space. They fall in two groups, the aspartate/glutamate exchangers, AGCs, major components of the NADH malate aspartate shuttle (MAS) and urea cycle, and the ATP-Mg(2+)/Pi exchangers or short CaMCs (APCs or SCaMCs). The AGCs are activated by relatively low Ca(2+) levels only slightly higher than resting Ca(2+), whereas all SCaMCs studied so far require strong Ca(2+) signals, above micromolar, for activation. In addition, AGCs are not strictly Ca(2+) dependent, being active even in Ca(2+)-free conditions. Thus, AGCs are well suited to respond to small Ca(2+) signals and that do not reach mitochondria. In contrast, ATP-Mg(2+)/Pi carriers are inactive in Ca(2+) free conditions and activation requires Ca(2+) signals that will also activate the calcium uniporter (MCU). By changing the net content of adenine nucleotides of the matrix upon activation, SCaMCs regulate the activity of the permeability transition pore, and the Ca(2+) retention capacity of mitochondria (CRC), two functions synergizing with those of the MCU. The different Ca(2+) activation properties of the two CaMCs are discussed in relation to their newly obtained structures. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Araceli Del Arco
- Facultad de Ciencias Ambientales y Bioquímica, Centro RegionaI de Investigaciones Biomédicas, Universidad de Castilla la Mancha, Toledo 45071, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain
| | - Jorgina Satrustegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Madrid, Spain.
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Maciejak P, Szyndler J, Turzyńska D, Sobolewska A, Kołosowska K, Krząścik P, Płaźnik A. Is the interaction between fatty acids and tryptophan responsible for the efficacy of a ketogenic diet in epilepsy? The new hypothesis of action. Neuroscience 2016; 313:130-48. [DOI: 10.1016/j.neuroscience.2015.11.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/10/2015] [Accepted: 11/13/2015] [Indexed: 01/09/2023]
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41
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Du J, Rountree A, Cleghorn WM, Contreras L, Lindsay KJ, Sadilek M, Gu H, Djukovic D, Raftery D, Satrústegui J, Kanow M, Chan L, Tsang SH, Sweet IR, Hurley JB. Phototransduction Influences Metabolic Flux and Nucleotide Metabolism in Mouse Retina. J Biol Chem 2015; 291:4698-710. [PMID: 26677218 DOI: 10.1074/jbc.m115.698985] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 01/20/2023] Open
Abstract
Production of energy in a cell must keep pace with demand. Photoreceptors use ATP to maintain ion gradients in darkness, whereas in light they use it to support phototransduction. Matching production with consumption can be accomplished by coupling production directly to consumption. Alternatively, production can be set by a signal that anticipates demand. In this report we investigate the hypothesis that signaling through phototransduction controls production of energy in mouse retinas. We found that respiration in mouse retinas is not coupled tightly to ATP consumption. By analyzing metabolic flux in mouse retinas, we also found that phototransduction slows metabolic flux through glycolysis and through intermediates of the citric acid cycle. We also evaluated the relative contributions of regulation of the activities of α-ketoglutarate dehydrogenase and the aspartate-glutamate carrier 1. In addition, a comprehensive analysis of the retinal metabolome showed that phototransduction also influences steady-state concentrations of 5'-GMP, ribose-5-phosphate, ketone bodies, and purines.
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Affiliation(s)
- Jianhai Du
- From the Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington 98109
| | | | | | - Laura Contreras
- Department of Molecular Biology, Centre for Molecular Biology Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Científicas, CIBER of Rare Diseases (CIBERER), and Health Research Institute Jimenez Diaz Foundation, Autonomous University of Madrid, 28049 Madrid, Spain
| | | | | | - Haiwei Gu
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Danijel Djukovic
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Dan Raftery
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine
| | - Jorgina Satrústegui
- Department of Molecular Biology, Centre for Molecular Biology Severo Ochoa, Universidad Autonoma de Madrid-Consejo Superior de Investigaciones Científicas, CIBER of Rare Diseases (CIBERER), and Health Research Institute Jimenez Diaz Foundation, Autonomous University of Madrid, 28049 Madrid, Spain
| | | | - Lawrence Chan
- Bernard and Shirlee Brown Glaucoma Laboratory and Barbara and Donald Jonas Stem Cell Laboratory, Department of Ophthalmology, Columbia University, New York, New York, and
| | - Stephen H Tsang
- Bernard and Shirlee Brown Glaucoma Laboratory and Barbara and Donald Jonas Stem Cell Laboratory, Department of Ophthalmology, Columbia University, New York, New York, and Department of Pathology and Cell Biology and Institute of Human Nutrition, Columbia University, New York, New York 10032
| | | | - James B Hurley
- From the Department of Biochemistry, Department of Ophthalmology, University of Washington, Seattle, Washington 98109,
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Lu Y, Tucker D, Dong Y, Zhao N, Zhuo X, Zhang Q. Role of Mitochondria in Neonatal Hypoxic-Ischemic Brain Injury. JOURNAL OF NEUROSCIENCE AND REHABILITATION 2015; 2:1-14. [PMID: 27441209 PMCID: PMC4948590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Hypoxic-ischemia (HI) causes severe brain injury in neonates. It's one of the leading causes to neonatal death and pediatric disability, resulting in devastating consequences, emotionally and economically, to their families. A series of events happens in this process, e.g. excitatory transmitter release, extracelluar Ca2+ influxing, mitochondrial dysfunction, energy failure, and neuron death. There are two forms of neuron death after HI insult: necrosis and apoptosis, apoptosis being the more prevalent form. Mitochondria handle a series of oxidative reactions, and yield energy for various cellular activities including the maintainance of membrane potential and preservation of intracellular ionic homeostasis. Therefore mitochondria play a critical role in neonatal neurodegeneration following HI, and mitochondrial dysfunction is the key point in neurodegenerative evolution. Because of this, exploring effective mitochondria-based clinical strategies is crucial. Today the only efficacious clinic treatment is hypothermia. However, due to its complex management, clinical complication and autoimmune decrease, its clinical application is limited. So far, many mitochondria-based strategies have been reported neuroprotective in animal models, which offers promise on neonatal therapy. However, since their clinical effectiveness are still unclear, plenty of studies need to be continued in the future. According to recent reports, two novel strategies have been proposed: methylene blue (MB) and melatonin. Although they are still in primary stage, the underlying mechanisms indicate promising clinical applications. Every neurological therapeutic strategy has its intrinsic deficit and limited efficacy, therefore in the long run, the perfect clinical therapy for hypoxic-ischemic neonatal brain injury will be based on the combination of multiple strategies.
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Affiliation(s)
- Yujiao Lu
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
| | - Donovan Tucker
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
| | - Yan Dong
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
| | - Ningjun Zhao
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
| | - Xiaoying Zhuo
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
| | - Quanguang Zhang
- Department of Neuroscience & Regenerative Medicine, Georgia Regents University, USA
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Gusdon AM, Fernandez-Bueno GA, Wohlgemuth S, Fernandez J, Chen J, Mathews CE. Respiration and substrate transport rates as well as reactive oxygen species production distinguish mitochondria from brain and liver. BMC BIOCHEMISTRY 2015; 16:22. [PMID: 26358560 PMCID: PMC4564979 DOI: 10.1186/s12858-015-0051-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 09/02/2015] [Indexed: 12/04/2022]
Abstract
BACKGROUND Aberrant mitochondrial function, including excessive reactive oxygen species (ROS) production, has been implicated in the pathogenesis of human diseases. The use of mitochondrial inhibitors to ascertain the sites in the electron transport chain (ETC) resulting in altered ROS production can be an important tool. However, the response of mouse mitochondria to ETC inhibitors has not been thoroughly assessed. Here we set out to characterize the differences in phenotypic response to ETC inhibitors between the more energetically demanding brain mitochondria and less energetically demanding liver mitochondria in commonly utilized C57BL/6J mice. RESULTS We show that in contrast to brain mitochondria, inhibiting distally within complex I or within complex III does not increase liver mitochondrial ROS production supported by complex I substrates, and liver mitochondrial ROS production supported by complex II substrates occurred primarily independent of membrane potential. Complex I, II, and III enzymatic activities and membrane potential were equivalent between liver and brain and responded to ETC. inhibitors similarly. Brain mitochondria exhibited an approximately two-fold increase in complex I and II supported respiration compared with liver mitochondria while exhibiting similar responses to inhibitors. Elevated NADH transport and heightened complex II-III coupled activity accounted for increased complex I and II supported respiration, respectively in brain mitochondria. CONCLUSIONS We conclude that important mechanistic differences exist between mouse liver and brain mitochondria and that mouse mitochondria exhibit phenotypic differences compared with mitochondria from other species.
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Affiliation(s)
- Aaron M Gusdon
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida College of Medicine, Gainesville, FL, 32610, USA.
- Department of Neurology, Weill Cornell Medical Center/NewYork-Presbyterian Hospital, New York, NY, 10065, USA.
| | - Gabriel A Fernandez-Bueno
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida College of Medicine, Gainesville, FL, 32610, USA.
| | - Stephanie Wohlgemuth
- Department of Animal Sciences, Institute of Food and Agricultural Sciences, The University of Florida, Gainesville, FL, 32610, USA.
| | - Jenelle Fernandez
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida College of Medicine, Gainesville, FL, 32610, USA.
| | - Jing Chen
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida College of Medicine, Gainesville, FL, 32610, USA.
| | - Clayton E Mathews
- Department of Pathology, Immunology, and Laboratory Medicine, The University of Florida College of Medicine, Gainesville, FL, 32610, USA.
- , Present address: 1275 Center Dr, Room J597, P.O. Box 100275, Gainesville, FL, 32610-0275, USA.
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Contreras L. Role of AGC1/aralar in the metabolic synergies between neuron and glia. Neurochem Int 2015; 88:38-46. [DOI: 10.1016/j.neuint.2015.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/30/2015] [Accepted: 04/07/2015] [Indexed: 10/23/2022]
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Lange SC, Winkler U, Andresen L, Byhrø M, Waagepetersen HS, Hirrlinger J, Bak LK. Dynamic Changes in Cytosolic ATP Levels in Cultured Glutamatergic Neurons During NMDA-Induced Synaptic Activity Supported by Glucose or Lactate. Neurochem Res 2015; 40:2517-26. [PMID: 26184116 DOI: 10.1007/s11064-015-1651-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 06/17/2015] [Accepted: 06/23/2015] [Indexed: 11/30/2022]
Abstract
We have previously shown that synaptic transmission fails in cultured neurons in the presence of lactate as the sole substrate. Thus, to test the hypothesis that the failure of synaptic transmission is a consequence of insufficient energy supply, ATP levels were monitored employing the ATP biosensor Ateam1.03YEMK. While inducing synaptic activity by subjecting cultured neurons to two 30 s pulses of NMDA (30 µM) with a 4 min interval, changes in relative ATP levels were measured in the presence of lactate (1 mM), glucose (2.5 mM) or the combination of the two. ATP levels reversibly declined following NMDA-induced neurotransmission activity, as indicated by a reversible 10-20 % decrease in the response of the biosensor. The responses were absent when the NMDA receptor antagonist memantine was present. In the presence of lactate alone, the ATP response dropped significantly more than in the presence of glucose following the 2nd pulse of NMDA (approx. 10 vs. 20 %). Further, cytosolic Ca(2+) homeostasis during NMDA-induced synaptic transmission is partially inhibited by verapamil indicating that voltage-gated Ca(2+) channels are activated. Lastly, we showed that cytosolic Ca(2+) homeostasis is supported equally well by both glucose and lactate, and that a pulse of NMDA causes accumulation of Ca(2+) in the mitochondrial matrix. In summary, we have shown that ATP homeostasis during neurotransmission activity in cultured neurons is supported by both glucose and lactate. However, ATP homeostasis seems to be negatively affected by the presence of lactate alone, suggesting that glucose is needed to support neuronal energy metabolism during activation.
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Affiliation(s)
- Sofie C Lange
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Ulrike Winkler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Liebigstr. 27, 04103, Leipzig, Germany
| | - Lars Andresen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, 15 Grønnegårdsvej, 1870, Frederiksberg, Denmark
| | - Mathilde Byhrø
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Johannes Hirrlinger
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Liebigstr. 27, 04103, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, 37075, Göttingen, Germany
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100, Copenhagen, Denmark.
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Fluctuations in Cytosolic Calcium Regulate the Neuronal Malate-Aspartate NADH Shuttle: Implications for Neuronal Energy Metabolism. Neurochem Res 2015; 40:2425-30. [PMID: 26138554 DOI: 10.1007/s11064-015-1652-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/15/2015] [Accepted: 06/23/2015] [Indexed: 12/21/2022]
Abstract
The malate-aspartate NADH shuttle (MAS) operates in neurons and other cells to translocate reducing equivalents from the cytosol to the mitochondrial matrix, thus allowing a continued flux through the glycolytic pathway and metabolism of extracellular lactate. Recent discoveries have taught us that MAS is regulated by fluctuations in cytosolic Ca(2+) levels, and that this regulation is required to maintain a tight coupling between neuronal activity and mitochondrial respiration and oxidative phosphorylation. At cytosolic Ca(2+) fluctuations below the threshold of the mitochondrial calcium uniporter, there is a positive correlation between Ca(2+) and MAS activity; however, if cytosolic Ca(2+) increases above the threshold, MAS activity is thought to be reduced by an intricate mechanism. The latter forces the neurons to partly rely on anaerobic glycolysis producing lactate that may be metabolized subsequently, by neurons or other cells. In this review, we will discuss the evidence for Ca(2+)-mediated regulation of MAS that have been uncovered over the last decade or so, together with the need for further verification, and examine the metabolic ramifications for neurons.
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Mitochondrial ATP-Mg/Pi carrier SCaMC-3/Slc25a23 counteracts PARP-1-dependent fall in mitochondrial ATP caused by excitotoxic insults in neurons. J Neurosci 2015; 35:3566-81. [PMID: 25716855 DOI: 10.1523/jneurosci.2702-14.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Glutamate excitotoxicity is caused by sustained activation of neuronal NMDA receptors causing a large Ca(2+) and Na(+) influx, activation of poly(ADP ribose) polymerase-1 (PARP-1), and delayed Ca(2+) deregulation. Mitochondria undergo early changes in membrane potential during excitotoxicity, but their precise role in these events is still controversial. Using primary cortical neurons derived from mice, we show that NMDA exposure results in a rapid fall in mitochondrial ATP in neurons deficient in SCaMC-3/Slc25a23, a Ca(2+)-regulated mitochondrial ATP-Mg/Pi carrier. This fall is associated with blunted increases in respiration and a delayed decrease in cytosolic ATP levels, which are prevented by PARP-1 inhibitors or by SCaMC-3 activity promoting adenine nucleotide uptake into mitochondria. SCaMC-3 KO neurons show an earlier delayed Ca(2+) deregulation, and SCaMC-3-deficient mitochondria incubated with ADP or ATP-Mg had reduced Ca(2+) retention capacity, suggesting a failure to maintain matrix adenine nucleotides as a cause for premature delayed Ca(2+) deregulation. SCaMC-3 KO neurons have higher vulnerability to in vitro excitotoxicity, and SCaMC-3 KO mice are more susceptible to kainate-induced seizures, showing that early PARP-1-dependent fall in mitochondrial ATP levels, counteracted by SCaMC-3, is an early step in the excitotoxic cascade.
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Korzeniewski B. 'Idealized' state 4 and state 3 in mitochondria vs. rest and work in skeletal muscle. PLoS One 2015; 10:e0117145. [PMID: 25647747 PMCID: PMC4412265 DOI: 10.1371/journal.pone.0117145] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/19/2014] [Indexed: 11/18/2022] Open
Abstract
A computer model of oxidative phosphorylation (OXPHOS) in skeletal muscle is used to compare state 3, intermediate state and state 4 in mitochondria with rest and work in skeletal muscle. 'Idealized' state 4 and 3 in relation to various 'experimental' states 4 and 3 are defined. Theoretical simulations show, in accordance with experimental data, that oxygen consumption (V'O2), ADP and Pi are higher, while ATP/ADP and Δp are lower in rest than in state 4, because of the presence of basal ATP consuming reactions in the former. It is postulated that moderate and intensive work in skeletal muscle is very different from state 3 in isolated mitochondria. V'O2, ATP/ADP, Δp and the control of ATP usage over V'O2 are much higher, while ADP and Pi are much lower in the former. The slope of the phenomenological V'O2-ADP relationship is much steeper during the rest-work transition than during the state 4-state 3 transition. The work state in intact muscle is much more similar to intermediate state than to state 3 in isolated mitochondria in terms of ADP, ATP/ADP, Δp and metabolic control pattern, but not in terms of V'O2. The huge differences between intact muscle and isolated mitochondria are proposed to be caused by the presence of the each-step activation (ESA) mechanism of the regulation of OXPHOS in intact skeletal muscle. Generally, the present study suggests that isolated mitochondria (at least in the absence of Ca2+) cannot serve as a good model of OXPHOS regulation in intact skeletal muscle.
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Affiliation(s)
- Bernard Korzeniewski
- Faculty of Biochemistry, Biophysics and Biotechnology,
Jagiellonian University, Kraków, Poland
- * E-mail:
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Kane DA. Lactate oxidation at the mitochondria: a lactate-malate-aspartate shuttle at work. Front Neurosci 2014; 8:366. [PMID: 25505376 PMCID: PMC4243568 DOI: 10.3389/fnins.2014.00366] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/25/2014] [Indexed: 11/30/2022] Open
Abstract
Lactate, the conjugate base of lactic acid occurring in aqueous biological fluids, has been derided as a “dead-end” waste product of anaerobic metabolism. Catalyzed by the near-equilibrium enzyme lactate dehydrogenase (LDH), the reduction of pyruvate to lactate is thought to serve to regenerate the NAD+ necessary for continued glycolytic flux. Reaction kinetics for LDH imply that lactate oxidation is rarely favored in the tissues of its own production. However, a substantial body of research directly contradicts any notion that LDH invariably operates unidirectionally in vivo. In the current Perspective, a model is forwarded in which the continuous formation and oxidation of lactate serves as a mitochondrial electron shuttle, whereby lactate generated in the cytosol of the cell is oxidized at the mitochondria of the same cell. From this perspective, an intracellular lactate shuttle operates much like the malate-aspartate shuttle (MAS); it is also proposed that the two shuttles are necessarily interconnected in a lactate-MAS. Among the requisite features of such a model, significant compartmentalization of LDH, much like the creatine kinase of the phosphocreatine shuttle, would facilitate net cellular lactate oxidation in a variety of cell types.
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Affiliation(s)
- Daniel A Kane
- Department of Human Kinetics, St. Francis Xavier University Antigonish, NS, Canada
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50
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Egnatchik RA, Leamy AK, Jacobson DA, Shiota M, Young JD. ER calcium release promotes mitochondrial dysfunction and hepatic cell lipotoxicity in response to palmitate overload. Mol Metab 2014; 3:544-53. [PMID: 25061559 PMCID: PMC4099508 DOI: 10.1016/j.molmet.2014.05.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 12/22/2022] Open
Abstract
Palmitate overload induces hepatic cell dysfunction characterized by enhanced apoptosis and altered citric acid cycle (CAC) metabolism; however, the mechanism of how this occurs is incompletely understood. We hypothesize that elevated doses of palmitate disrupt intracellular calcium homeostasis resulting in a net flux of calcium from the ER to mitochondria, activating aberrant oxidative metabolism. We treated primary hepatocytes and H4IIEC3 cells with palmitate and calcium chelators to identify the roles of intracellular calcium flux in lipotoxicity. We then applied 13C metabolic flux analysis (MFA) to determine the impact of calcium in promoting palmitate-stimulated mitochondrial alterations. Co-treatment with the calcium-specific chelator BAPTA resulted in a suppression of markers for apoptosis and oxygen consumption. Additionally, 13C MFA revealed that BAPTA co-treated cells had reduced CAC fluxes compared to cells treated with palmitate alone. Our results demonstrate that palmitate-induced lipoapoptosis is dependent on calcium-stimulated mitochondrial activation, which induces oxidative stress.
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Key Words
- APE, atom percent enrichment
- BSA, bovine serum albumin
- CAC, citric acid cycle
- ER stress
- FFA, free fatty acid
- Fatty liver
- GC–MS, gas chromatography–mass spectrometry
- H2DCFDA, 2′,7′-dichlorodihydrofluorescein diacetate
- Lipotoxicity
- MFA, metabolic flux analysis
- MUFA, monounsaturated fatty acid
- Metabolic flux analysis
- NAFLD, non-alcoholic fatty liver disease
- NASH, non-alcoholic steatohepatitis
- OA, oleate
- Oxidative stress
- PA, palmitate
- PI, propidium iodide
- ROS, reactive oxygen species
- SERCA, sarcoplasmic-endoplasmic reticulum calcium ATPase
- SFA, saturated fatty acid
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Affiliation(s)
- Robert A. Egnatchik
- Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Alexandra K. Leamy
- Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - David A. Jacobson
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Masakazu Shiota
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Jamey D. Young
- Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
- Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
- Corresponding author. Chemical and Biomolecular Engineering, VU Station B 351604, Vanderbilt University, Nashville, TN, USA. Tel.: +1 615 343 4253; fax: +1 615 343 7951.
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