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Zhou J, Zhang L, Peng J, Zhang X, Zhang F, Wu Y, Huang A, Du F, Liao Y, He Y, Xie Y, Gu L, Kuang C, Ou W, Xie M, Tu T, Pang J, Zhang D, Guo K, Feng Y, Yin S, Cao Y, Li T, Jiang Y. Astrocytic LRP1 enables mitochondria transfer to neurons and mitigates brain ischemic stroke by suppressing ARF1 lactylation. Cell Metab 2024:S1550-4131(24)00192-X. [PMID: 38906140 DOI: 10.1016/j.cmet.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 09/11/2023] [Accepted: 05/23/2024] [Indexed: 06/23/2024]
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1) is an endocytic/signaling cell-surface receptor that regulates diverse cellular functions, including cell survival, differentiation, and proliferation. LRP1 has been previously implicated in the pathogenesis of neurodegenerative disorders, but there are inconsistencies in its functions. Therefore, whether and how LRP1 maintains brain homeostasis remains to be clarified. Here, we report that astrocytic LRP1 promotes astrocyte-to-neuron mitochondria transfer by reducing lactate production and ADP-ribosylation factor 1 (ARF1) lactylation. In astrocytes, LRP1 suppressed glucose uptake, glycolysis, and lactate production, leading to reduced lactylation of ARF1. Suppression of astrocytic LRP1 reduced mitochondria transfer into damaged neurons and worsened ischemia-reperfusion injury in a mouse model of ischemic stroke. Furthermore, we examined lactate levels in human patients with stroke. Cerebrospinal fluid (CSF) lactate was elevated in stroke patients and inversely correlated with astrocytic mitochondria. These findings reveal a protective role of LRP1 in brain ischemic stroke by enabling mitochondria-mediated astrocyte-neuron crosstalk.
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Affiliation(s)
- Jian Zhou
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China; Sichuan Clinical Research Center for Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Lifang Zhang
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China; Sichuan Clinical Research Center for Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Jianhua Peng
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China; Institute of Epigenetics and Brain Science, Southwest Medical University, Luzhou 646000, China; Academician (Expert) Workstation of Sichuan Province, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Xianhui Zhang
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Fan Zhang
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China; Sichuan Clinical Research Center for Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yuanyuan Wu
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - An Huang
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Fengling Du
- Department of Neonatology, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yuyan Liao
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yijing He
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yuke Xie
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Long Gu
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Chenghao Kuang
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Wei Ou
- Department of Anesthesiology, Laboratory of Mitochondrial Metabolism and Perioperative Medicine, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Maodi Xie
- Department of Anesthesiology, Laboratory of Mitochondrial Metabolism and Perioperative Medicine, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Tianqi Tu
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Jinwei Pang
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Dingkun Zhang
- Laboratory of Clinical Proteomics and Metabolomics, Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Kecheng Guo
- Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yue Feng
- Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Department of Nuclear Medicine, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Shigang Yin
- Institute of Epigenetics and Brain Science, Southwest Medical University, Luzhou 646000, China; Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China
| | - Yang Cao
- Department of Cardiology, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China; School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Tao Li
- Department of Anesthesiology, Laboratory of Mitochondrial Metabolism and Perioperative Medicine, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China.
| | - Yong Jiang
- Department of Neurosurgery, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China; Institute of Epigenetics and Brain Science, Southwest Medical University, Luzhou 646000, China; Laboratory of Neurological Diseases and Brain Function, the Affiliated Hospital, Southwest Medical University, Luzhou 646000, China.
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Liu X, Liu S, Wang Y, Shi Y, Chen Q. New insights into the antibiofilm activity and mechanism of Mannosylerythritol Lipid-A against Listeria monocytogenes EGD-e. Biofilm 2024; 7:100201. [PMID: 38779407 PMCID: PMC11108854 DOI: 10.1016/j.bioflm.2024.100201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/28/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Listeria monocytogenes is one of the leading causative agents of foodborne disease outbreaks worldwide. Herein, the antibiofilm effect and mechanism of Mannosylerythritol Lipid-A against L. monocytogenes EGD-e is reported for the first time. MEL-A effectively attenuated biofilm formation while reducing the viability and motility of bacteria within the biofilm in the early stage, and influenced bacterial adhesion by affecting the secretion of extracellular polysaccharides and eDNA. RT-qPCR revealed that MEL-A significantly suppressed the expression of genes involved in flagellar movement and virulence. Untargeted LC-MS metabolomics indicated that MEL-A affected the fluidity and permeability of cell membranes by significantly upregulating unsaturated fatty acids, lipids and glycoside metabolites, and affected protein biosynthesis, nucleotide metabolism and DNA synthesis and repair by significantly downregulating amino acid metabolism and nucleic acid metabolism. These pathways may constitute the key targets of biofilm formation inhibition by MEL-A. Furthermore, MEL-A showed good removal effects on mature biofilms under different temperatures, different materials and milk. Our data indicated that MEL-A could be used as a novel antibiofilm agent to improve food safety. Our study provides new insights into the possible inhibitory mechanism of MEL-A and the response of L. monocytogenes EGD-e to MEL-A.
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Affiliation(s)
- Xiayu Liu
- Innovation Center of Yangtze River Delta, Zhejiang University, Jiashan, 314100, China
| | - Siyu Liu
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
- Innovation Center of Yangtze River Delta, Zhejiang University, Jiashan, 314100, China
| | - Yuxi Wang
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
| | - Ying Shi
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
| | - Qihe Chen
- Department of Food Science and Nutrition, Zhejiang University, Hangzhou, 310058, China
- Innovation Center of Yangtze River Delta, Zhejiang University, Jiashan, 314100, China
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NAD + metabolism drives astrocyte proinflammatory reprogramming in central nervous system autoimmunity. Proc Natl Acad Sci U S A 2022; 119:e2211310119. [PMID: 35994674 PMCID: PMC9436380 DOI: 10.1073/pnas.2211310119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). Astrocytes are the most abundant glial cells in the CNS, and their dysfunction contributes to the pathogenesis of MS and its animal model, experimental autoimmune encephalomyelitis (EAE). Recent advances highlight the pivotal role of cellular metabolism in programming immune responses. However, the underlying immunometabolic mechanisms that drive astrocyte pathogenicity remain elusive. Nicotinamide adenine dinucleotide (NAD+) is a vital coenzyme involved in cellular redox reactions and a substrate for NAD+-dependent enzymes. Cellular NAD+ levels are dynamically controlled by synthesis and degradation, and dysregulation of this balance has been associated with inflammation and disease. Here, we demonstrate that cell-autonomous generation of NAD+ via the salvage pathway regulates astrocyte immune function. Inhibition of nicotinamide phosphoribosyltransferase (NAMPT), a key enzyme in the salvage pathway, results in depletion of NAD+, inhibits oxidative phosphorylation, and limits astrocyte inflammatory potential. We identified CD38 as the main NADase up-regulated in reactive mouse and human astrocytes in models of neuroinflammation and MS. Genetic or pharmacological blockade of astrocyte CD38 activity augmented NAD+ levels, suppressed proinflammatory transcriptional reprogramming, impaired chemotactic potential to inflammatory monocytes, and ameliorated EAE. We found that CD38 activity is mediated via calcineurin/NFAT signaling in mouse and human reactive astrocytes. Thus, NAMPT-NAD+-CD38 circuitry in astrocytes controls their ability to meet their energy demands and drives the expression of proinflammatory transcriptional modules, contributing to CNS pathology in EAE and, potentially, MS. Our results identify candidate therapeutic targets in MS.
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Chenna S, Koopman WJH, Prehn JHM, Connolly NMC. Mechanisms and mathematical modelling of ROS production by the mitochondrial electron transport chain. Am J Physiol Cell Physiol 2022; 323:C69-C83. [PMID: 35613354 DOI: 10.1152/ajpcell.00455.2021] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Reactive oxygen species (ROS) are recognised both as damaging molecules and intracellular signalling entities. In addition to its role in ATP generation, the mitochondrial electron transport chain (ETC) constitutes a relevant source of mitochondrial ROS, in particular during pathological conditions. Mitochondrial ROS homeostasis depends on species- and site-dependent ROS production, their bioreactivity, diffusion, and scavenging. However, our quantitative understanding of mitochondrial ROS homeostasis has thus far been hampered by technical limitations, including lack of truly site- and/or ROS-specific reporter molecules. In this context, the use of computational models is of great value to complement and interpret empirical data, as well as to predict variables that are difficult to assess experimentally. During the last decades, various mechanistic models of ETC-mediated ROS production have been developed. Although these often-complex models have generated novel insights, their parameterisation, analysis, and integration with other computational models is not straightforward. In contrast, phenomenological (sometimes termed "minimal") models use a relatively small set of equations to describe empirical relationship(s) between ROS-related and other parameters, and generally aim to explore system behaviour and generate hypotheses for experimental validation. In this review, we first discuss ETC-linked ROS homeostasis and introduce various detailed mechanistic models. Next, we present how bioenergetic parameters (e.g. NADH/NAD+ ratio, mitochondrial membrane potential) relate to site-specific ROS production within the ETC and how these relationships can be used to design minimal models of ROS homeostasis. Finally, we illustrate how minimal models have been applied to explore pathophysiological aspects of ROS.
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Affiliation(s)
- Sandeep Chenna
- Centre for Systems Medicine, Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Werner J H Koopman
- Department of Pediatrics, Amalia Children's Hospital, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud Center for Mitochondrial Disorders (RCMM), Radboud University Medical Center (Radboudumc), Nijmegen, The Netherlands.,Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Jochen H M Prehn
- Centre for Systems Medicine, Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,SFI FutureNeuro Research Centre, Dublin, Ireland
| | - Niamh M C Connolly
- Centre for Systems Medicine, Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
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Hou W, Chen Q, Wang H, Qiu P, Lyu X, Chen W, Chua MLK, Chinn YE, Deng CX, Wang R. The metabolic footprint during adipocyte commitment highlights ceramide modulation as an adequate approach for obesity treatment. EBioMedicine 2020; 51:102605. [PMID: 31901865 PMCID: PMC6940659 DOI: 10.1016/j.ebiom.2019.102605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Metabolic modulation is capable of maintaining cell potency, regulating niche homeostasis, or determining cell fate. However, little is known regarding the metabolic landscape during early adipogenesis or whether metabolic modulation could be a potential approach for obesity treatment. METHODS The metabolic footprint during adipocyte commitment was evaluated by metabolomics analysis in mouse embryonic fibroblasts (MEFs). The role of apoptosis induced by ceramide and how ceramide is regulated were evaluated by omics analysis in vitro, human database and the adipocyte-specific Sirt1 knockout mouse. FINDINGS The metabolic footprint showed that a complicated diversity of metabolism was enriched as early as 3 h and tended to fluctuate throughout differentiation. Subsequently, the scale of these perturbed metabolic patterns was reduced to reach a balanced state. Of high relevance is the presence of apoptosis induced by ceramide accumulation, which is associated with metabolic dynamics. Interestingly, apoptotic cells were not merely a byproduct of adipogenesis but rather promoted the release of lipid components to facilitate adipogenesis. Mechanistically, ceramide accumulation stemming from hydrolysis and the de novo pathway during early adipogenesis is regulated by Sirt1 upon epigenetic alterations of constitutive Histone H3K4 methylation and H3K9 acetylation. INTERPRETATION The metabolic footprint during adipocyte commitment highlights that apoptosis induced by ceramide is essential for adipogenesis, which is reversed by suppression of Sirt1. Therefore, Sirt1 may constitute a target to treat obesity or other ceramide-associated metabolic syndromes. FUNDING This project was supported by grants from the University of Macau (SRG2015-00008-FHS, MYRG2016-00054-FHS and MYRG2017-00096-FHS to RHW; CPG2019-00019-FHS to CXD) and from the National Natural Science Foundation of China (81672603 and 81401978) to QC.
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Affiliation(s)
- Weilong Hou
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Qiang Chen
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Haitao Wang
- Faculty of Health Sciences, University of Macau, Macau SAR, China; Division of Radiation Oncology, National Cancer Centre Singapore, Singapore; Division of Medical Sciences, National Cancer Centre Singapore, Singapore; Oncology Academic Programme, Duke-NUS Medical School, Singapore
| | - Pengxiang Qiu
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Xueying Lyu
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Weiping Chen
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, United States
| | - Melvin L K Chua
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore; Division of Medical Sciences, National Cancer Centre Singapore, Singapore; Oncology Academic Programme, Duke-NUS Medical School, Singapore
| | - Y Eugene Chinn
- Institute of Biology and Medical Sciences, Soochow University School of Medicine, 199# Ren'ai Road, Suzhou Jiangsu 215123, China
| | - Chu-Xia Deng
- Faculty of Health Sciences, University of Macau, Macau SAR, China.
| | - Ruihong Wang
- Faculty of Health Sciences, University of Macau, Macau SAR, China; Center for Cancer Research, Nation Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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Xu JZ, Ruan HZ, Chen XL, Zhang F, Zhang W. Equilibrium of the intracellular redox state for improving cell growth and L-lysine yield of Corynebacterium glutamicum by optimal cofactor swapping. Microb Cell Fact 2019; 18:65. [PMID: 30943966 PMCID: PMC6448238 DOI: 10.1186/s12934-019-1114-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/28/2019] [Indexed: 02/06/2023] Open
Abstract
Background NAD(H/+) and NADP(H/+) are the most important redox cofactors in bacteria. However, the intracellular redox balance is in advantage of the cell growth and production of NAD(P)H-dependent products. Results In this paper, we rationally engineered glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and isocitrate dehydrogenase (IDH) to switch the nucleotide-cofactor specificity resulting in an increase in final titer [from 85.6 to 121.4 g L−1] and carbon yield [from 0.33 to 0.46 g (g glucose)−1] of l-lysine in strain RGI in fed-batch fermentation. To do this, we firstly analyzed the production performance of original strain JL-6, indicating that the imbalance of intracellular redox was the limiting factor for l-lysine production. Subsequently, we modified the native GAPDH and indicated that recombinant strain RG with nonnative NADP-GAPDH dramatically changed the intracellular levels of NADH and NADPH. However, l-lysine production did not significantly increase because cell growth was harmed at low NADH level. Lastly, the nonnative NAD-IDH was introduced in strain RG to increase the NADH availability and to equilibrate the intracellular redox. The resulted strain RGI showed the stable ratio of NADPH/NADH at about 1.00, which in turn improved cell growth (μmax. = 0.31 h−1) and l-lysine productivity (qLys, max. = 0.53 g g−1 h−1) as compared with strain RG (μmax. = 0.14 h−1 and qLys, max. = 0.42 g g−1 h−1). Conclusions This is the first report of balancing the intracellular redox state by switching the nucleotide-cofactor specificity of GAPDH and IDH, thereby improving cell growth and l-lysine production.![]() Electronic supplementary material The online version of this article (10.1186/s12934-019-1114-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian-Zhong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, Wuxi, 214122, China.
| | - Hao-Zhe Ruan
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, Wuxi, 214122, China
| | - Xiu-Lai Chen
- State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, 1800# Lihu Road, Wuxi, 214122, China
| | - Feng Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, Wuxi, 214122, China
| | - Weiguo Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, Wuxi, 214122, China
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Electrochemical Glucose Quantification as a Strategy for Ethanolic Fermentation Monitoring. CHEMOSENSORS 2019. [DOI: 10.3390/chemosensors7010014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The possibility of using an electrochemical biosensor, using screen-printed electrodes modified with a carbonaceous material and a commercial kit for the determination of glucose, to monitor an ethanolic fermentation was analyzed. The determination is based on the electrochemical oxidation reaction of NADH that occurs at a potential where the components of the kit do not generate a current signal, even in the presence of the fermentation medium. The electrochemical system was used to analyze the variation of glucose concentration during a laboratory-scale fermentation. The results were contrasted with the variation of standard characterization parameters such as pH, total soluble solids (TSS), the viability of the yeast, and concentration of ethanol produced. Of these values, the total soluble solids should be related to the concentration of glucose obtained by the electrochemical sensor, however, this last measure is more specific for sugar since the TSS refers to all soluble solids. The obtained results allow us to verify the usefulness of the electrochemical method for real-time monitoring of a fermentation.
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Calì C, Tauffenberger A, Magistretti P. The Strategic Location of Glycogen and Lactate: From Body Energy Reserve to Brain Plasticity. Front Cell Neurosci 2019; 13:82. [PMID: 30894801 PMCID: PMC6415680 DOI: 10.3389/fncel.2019.00082] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/18/2019] [Indexed: 01/08/2023] Open
Abstract
Brain energy metabolism has been the object of intense research in recent years. Pioneering work has identified the different cell types involved in energy production and use. Recent evidence has demonstrated a key role of L-Lactate in brain energy metabolism, producing a paradigm-shift in our understanding of the neuronal energy metabolism. At the center of this shift, is the identification of a central role of astrocytes in neuroenergetics. Thanks to their morphological characteristics, they are poised to take up glucose from the circulation and deliver energy substrates to neurons. Astrocyte neuron lactate shuttle (ANLS) model, has shown that the main energy substrate that astrocytes deliver to neurons is L-Lactate, to sustain neuronal oxidative metabolism. L-Lactate can also be produced from glycogen, the storage form of glucose, which is exclusively localized in astrocytes. Inhibition of glycogen metabolism and the ensuing inhibition of L-Lactate production leads to cognitive dysfunction. Experimental evidence indicates that the role of lactate in cognitive function relates not only to its role as a metabolic substrate for neurons but also as a signaling molecule for synaptic plasticity. Interestingly, a similar metabolic uncoupling appears to exist in peripheral tissues plasma, whereby glucose provides L-Lactate as the substrate for cellular oxidative metabolism. In this perspective article, we review the known information on the distribution of glycogen and lactate within brain cells, and how this distribution relates to the energy regime of glial vs. neuronal cells.
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Affiliation(s)
- Corrado Calì
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Arnaud Tauffenberger
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Pierre Magistretti
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Köhler S, Winkler U, Sicker M, Hirrlinger J. NBCe1 mediates the regulation of the NADH/NAD + redox state in cortical astrocytes by neuronal signals. Glia 2018; 66:2233-2245. [PMID: 30208253 DOI: 10.1002/glia.23504] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/19/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022]
Abstract
Astrocytes are a glial cell type, which is indispensable for brain energy metabolism. Within cells, the NADH/NAD+ redox state is a crucial node in metabolism connecting catabolic pathways to oxidative phosphorylation and ATP production in mitochondria. To characterize the dynamics of the intracellular NADH/NAD+ redox state in cortical astrocytes Peredox, a genetically encoded sensor for the NADH/NAD+ redox state, was expressed in cultured cortical astrocytes as well as in cortical astrocytes in acutely isolated brain slices. Calibration of the sensor in cultured astrocytes revealed a mean basal cytosolic NADH/NAD+ redox ratio of about 0.01; however, with a broad distribution and heterogeneity in the cell population, which was mirrored by a heterogeneous basal cellular concentration of lactate. Inhibition of glucose uptake decreased the NADH/NAD+ redox state while inhibition of lactate dehydrogenase or of lactate release resulted in an increase in the NADH/NAD+ redox ratio. Furthermore, the NADH/NAD+ redox state was regulated by the extracellular concentration of K+ , and application of the neurotransmitters ATP or glutamate increased the NADH/NAD+ redox state dependent on purinergic receptors and glutamate uptake, respectively. This regulation by K+ , ATP, and glutamate involved NBCe1 mediated sodium-bicarbonate transport. These results demonstrate that the NADH/NAD+ redox state in astrocytes is a metabolic node regulated by neuronal signals reflecting physiological activity, most likely contributing to adjust astrocytic metabolism to energy demand of the brain.
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Affiliation(s)
- Susanne Köhler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Ulrike Winkler
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Marit Sicker
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Johannes Hirrlinger
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
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Ji J, Zeng XN, Cao LL, Zhang L, Zhao Z, Yang DD, Sun XL. PPARβ/δ activation protects against corticosterone-induced ER stress in astrocytes by inhibiting the CpG hypermethylation of microRNA-181a. Neuropharmacology 2016; 113:396-406. [PMID: 27789312 DOI: 10.1016/j.neuropharm.2016.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/27/2016] [Accepted: 10/22/2016] [Indexed: 12/23/2022]
Abstract
Increasing evidence indicates that peroxisome proliferator-activated receptors (PPARs) play neuroprotective roles in various neurodegenerative disease models in vivo and in vitro. However, the underlying mechanisms remain unclear. Astrocyte proliferation is a key process in neural development and plays significant roles in the regeneration of neural tissue after a penetrating injury. Corticosterone can significantly reduce the expression of glial fibrillary acid protein (GFAP) in cultured rat hippocampal astrocytes in vitro, and induce astrocytic dysfunction. Our research found that corticosterone treatment resulted in astrocyte damage and reduced the expression of PPARβ/δ. GW0742, a selective and high-affinity PPARβ/δ agonist, attenuated the corticosterone-induced astrocyte damage, but also significantly reversed the increase in the expression of GRP78 and CHOP, the two predominant proteins in endoplasmic reticulum (ER) stress. Moreover, GW0742 decreased the levels of caspase-12 and cleaved caspase-3, thereby protecting astrocytes against corticosterone-induced astrocyte apoptosis. We then confirmed that GRP78 was a target gene of microRNA-181a and found that PPARβ/δ activation increased microRNA-181a levels. Finally, we demonstrated that PPARβ/δ activation by GW0742 noticeably inhibited the activities and expression of DNA methyltransferases, and reduced the corticosterone-induced CpG island hypermethylation of microRNA-181a1 in astrocytes. Therefore, the present study is the first to reveal that PPARβ/δ activation suppresses CpG island hypermethylation-associated silencing of microRNA-181a and thereby protects against ER stress-induced damage in astrocytes. Our findings suggest that PPARβ/δ activation in astrocytes might be a promising target for regulating ER stress-induced astrocytic injury.
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Affiliation(s)
- Juan Ji
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China
| | - Xiao-Ning Zeng
- The First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu 210029, China
| | - Lu-Lu Cao
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China
| | - Ling Zhang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China
| | - Zhan Zhao
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China
| | - Dan-Dan Yang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China
| | - Xiu-Lan Sun
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Road, Nanjing, Jiangsu 211166, China.
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Orellana JA, Retamal MA, Moraga-Amaro R, Stehberg J. Role of Astroglial Hemichannels and Pannexons in Memory and Neurodegenerative Diseases. Front Integr Neurosci 2016; 10:26. [PMID: 27489539 PMCID: PMC4951483 DOI: 10.3389/fnint.2016.00026] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/06/2016] [Indexed: 11/13/2022] Open
Abstract
Under physiological conditions, astroglial hemichannels and pannexons allow the release of gliotransmitters from astrocytes. These gliotransmitters are critical in modulating synaptic transmission, plasticity and memory. However, recent evidence suggests that under pathological conditions, they may be central in the development of various neurodegenerative diseases. Here we review current literature on the role of astroglial hemichannels and pannexons in memory, stress and the development of neurodegenerative diseases, and propose that they are not only crucial for normal brain function, including memory, but also a potential target for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Juan A Orellana
- Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Mauricio A Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Rodrigo Moraga-Amaro
- Laboratorio de Neurobiología, Centro de Investigaciones Biomédicas, Universidad Andres Bello Santiago, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Centro de Investigaciones Biomédicas, Universidad Andres Bello Santiago, Chile
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Dienel GA. The metabolic trinity, glucose-glycogen-lactate, links astrocytes and neurons in brain energetics, signaling, memory, and gene expression. Neurosci Lett 2015; 637:18-25. [PMID: 25725168 DOI: 10.1016/j.neulet.2015.02.052] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/23/2015] [Indexed: 10/23/2022]
Abstract
Glucose, glycogen, and lactate are traditionally identified with brain energetics, ATP turnover, and pathophysiology. However, recent studies extend their roles to include involvement in astrocytic signaling, memory consolidation, and gene expression. Emerging roles for these brain fuels and a readily-diffusible by-product are linked to differential fluxes in glycolytic and oxidative pathways, astrocytic glycogen dynamics, redox shifts, neuron-astrocyte interactions, and regulation of astrocytic activities by noradrenaline released from the locus coeruleus. Disproportionate utilization of carbohydrate compared with oxygen during brain activation is influenced by catecholamines, but its physiological basis is not understood and its magnitude may be affected by technical aspects of metabolite assays. Memory consolidation and gene expression are impaired by glycogenolysis blockade, and prevention of these deficits by injection of abnormally-high concentrations of lactate was interpreted as a requirement for astrocyte-to-neuron lactate shuttling in memory and gene expression. However, lactate transport was not measured and evidence for presumed shuttling is not compelling. In fact, high levels of lactate used to preserve memory consolidation and induce gene expression are sufficient to shut down neuronal firing via the HCAR1 receptor. In contrast, low lactate levels activate a receptor in locus coeruleus that stimulates noradrenaline release that may activate astrocytes throughout brain. Physiological relevance of exogenous concentrations of lactate used to mimic and evaluate metabolic, molecular, and behavioral effects of lactate requires close correspondence with the normal lactate levels, the biochemical and cellular sources and sinks, and specificity of lactate delivery to target cells.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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Crosstalk of Signaling and Metabolism Mediated by the NAD(+)/NADH Redox State in Brain Cells. Neurochem Res 2015; 40:2394-401. [PMID: 25876186 DOI: 10.1007/s11064-015-1526-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/16/2015] [Accepted: 01/23/2015] [Indexed: 12/26/2022]
Abstract
The energy metabolism of the brain has to be precisely adjusted to activity to cope with the organ's energy demand, implying that signaling regulates metabolism and metabolic states feedback to signaling. The NAD(+)/NADH redox state constitutes a metabolic node well suited for integration of metabolic and signaling events. It is affected by flux through metabolic pathways within a cell, but also by the metabolic state of neighboring cells, for example by lactate transferred between cells. Furthermore, signaling events both in neurons and astrocytes have been reported to change the NAD(+)/NADH redox state. Vice versa, a number of signaling events like astroglial Ca(2+) signals, neuronal NMDA-receptors as well as the activity of transcription factors are modulated by the NAD(+)/NADH redox state. In this short review, this bidirectional interdependence of signaling and metabolism involving the NAD(+)/NADH redox state as well as its potential relevance for the physiology of the brain and the whole organism in respect to blood glucose regulation and body weight control are discussed.
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Hertz L, Gibbs ME, Dienel GA. Fluxes of lactate into, from, and among gap junction-coupled astrocytes and their interaction with noradrenaline. Front Neurosci 2014; 8:261. [PMID: 25249930 PMCID: PMC4158791 DOI: 10.3389/fnins.2014.00261] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/04/2014] [Indexed: 01/06/2023] Open
Abstract
Lactate is a versatile metabolite with important roles in modulation of brain glucose utilization rate (CMRglc), diagnosis of brain-injured patients, redox- and receptor-mediated signaling, memory, and alteration of gene transcription. Neurons and astrocytes release and accumulate lactate using equilibrative monocarboxylate transporters that carry out net transmembrane transport of lactate only until intra- and extracellular levels reach equilibrium. Astrocytes have much faster lactate uptake than neurons and shuttle more lactate among gap junction-coupled astrocytes than to nearby neurons. Lactate diffusion within syncytia can provide precursors for oxidative metabolism and glutamate synthesis and facilitate its release from endfeet to perivascular space to stimulate blood flow. Lactate efflux from brain during activation underlies the large underestimation of CMRglc with labeled glucose and fall in CMRO2/CMRglc ratio. Receptor-mediated effects of lactate on locus coeruleus neurons include noradrenaline release in cerebral cortex and c-AMP-mediated stimulation of astrocytic gap junctional coupling, thereby enhancing its dispersal and release from brain. Lactate transport is essential for its multifunctional roles.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University Shenyang, China
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Clayton, VIC, Australia
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences Little Rock, AR, USA
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Hirrlinger J, Nave KA. Adapting brain metabolism to myelination and long-range signal transduction. Glia 2014; 62:1749-61. [DOI: 10.1002/glia.22737] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 07/23/2014] [Accepted: 07/23/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Johannes Hirrlinger
- Department of Neurogenetics; Max-Planck-Institute for Experimental Medicine; Göttingen Germany
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig; Leipzig Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics; Max-Planck-Institute for Experimental Medicine; Göttingen Germany
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Primary Cultures of Astrocytes and Neurons as Model Systems to Study the Metabolism and Metabolite Export from Brain Cells. BRAIN ENERGY METABOLISM 2014. [DOI: 10.1007/978-1-4939-1059-5_3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Protective effect of nicotinamide on high glucose/palmitate-induced glucolipotoxicity to INS-1 beta cells is attributed to its inhibitory activity to sirtuins. Arch Biochem Biophys 2013; 535:187-96. [PMID: 23562377 DOI: 10.1016/j.abb.2013.03.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/14/2013] [Accepted: 03/17/2013] [Indexed: 11/20/2022]
Abstract
This study was initiated to determine whether the protective effect of nicotinamide (NAM) on high glucose/palmitate (HG/PA)-induced INS-1 beta cell death was due to its role as an anti-oxidant, nicotinamide dinucleotide (NAD+) precursor, or inhibitor of NAD+-consuming enzymes such as poly (ADP-ribose) polymerase (PARP) or sirtuins. All anti-oxidants tested were not protective against HG/PA-induced INS-1 cell death. Direct supplementation of NAD+ or indirect supplementation through NAD+ salvage or de novo pathway did not protect the death. Knockdown of the NAD+ salvage pathway enzymes such as nicotinamide phosphoribosyl transferase (NAMPT) or nicotinamide mononucleotide adenyltransferase (NMNAT) did not augment death. On the other hand, pharmacological inhibition or knockdown of PARP did not affect death. However, sirtinol as an inhibitor of NAD-dependant deacetylase or knockdown of SIRT3 or SIRT4 significantly reduced the HG/PA-induced death. These data suggest that protective effect of NAM on beta cell glucolipotoxicity is attributed to its inhibitory activity on sirtuins.
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Bhatt DP, Houdek HM, Watt JA, Rosenberger TA. Acetate supplementation increases brain phosphocreatine and reduces AMP levels with no effect on mitochondrial biogenesis. Neurochem Int 2013; 62:296-305. [PMID: 23321384 DOI: 10.1016/j.neuint.2013.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/02/2013] [Accepted: 01/04/2013] [Indexed: 12/20/2022]
Abstract
Acetate supplementation in rats increases plasma acetate and brain acetyl-CoA levels. Although acetate is used as a marker to study glial energy metabolism, the effect that acetate supplementation has on normal brain energy stores has not been quantified. To determine the effect(s) that an increase in acetyl-CoA levels has on brain energy metabolism, we measured brain nucleotide, phosphagen and glycogen levels, and quantified cardiolipin content and mitochondrial number in rats subjected to acetate supplementation. Acetate supplementation was induced with glyceryl triacetate (GTA) by oral gavage (6 g/kg body weight). Rats used for biochemical analysis were euthanized using head-focused microwave irradiation at 2, and 4h following treatment to immediately stop metabolism. We found that acetate did not alter brain ATP, ADP, NAD, GTP levels, or the energy charge ratio [ECR, (ATP+½ ADP)/(ATP+ADP+AMP)] when compared to controls. However, after 4h of treatment brain phosphocreatine levels were significantly elevated with a concomitant reduction in AMP levels with no change in glycogen levels. In parallel studies where rats were treated with GTA for 28 days, we found that acetate did not alter brain glycogen and mitochondrial biogenesis as determined by measuring brain cardiolipin content, the fatty acid composition of cardiolipin and using quantitative ultra-structural analysis to determine mitochondrial density/unit area of cytoplasm in hippocampal CA3 neurons. Collectively, these data suggest that an increase in brain acetyl-CoA levels by acetate supplementation does increase brain energy stores however it has no effect on brain glycogen and neuronal mitochondrial biogenesis.
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Affiliation(s)
- Dhaval P Bhatt
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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Abstract
Metabolic signals are used for imaging and spectroscopic studies of brain function and disease and to elucidate the cellular basis of neuroenergetics. The major fuel for activated neurons and the models for neuron–astrocyte interactions have been controversial because discordant results are obtained in different experimental systems, some of which do not correspond to adult brain. In rats, the infrastructure to support the high energetic demands of adult brain is acquired during postnatal development and matures after weaning. The brain's capacity to supply and metabolize glucose and oxygen exceeds demand over a wide range of rates, and the hyperaemic response to functional activation is rapid. Oxidative metabolism provides most ATP, but glycolysis is frequently preferentially up-regulated during activation. Underestimation of glucose utilization rates with labelled glucose arises from increased lactate production, lactate diffusion via transporters and astrocytic gap junctions, and lactate release to blood and perivascular drainage. Increased pentose shunt pathway flux also causes label loss from C1 of glucose. Glucose analogues are used to assay cellular activities, but interpretation of results is uncertain due to insufficient characterization of transport and phosphorylation kinetics. Brain activation in subjects with low blood-lactate levels causes a brain-to-blood lactate gradient, with rapid lactate release. In contrast, lactate flooding of brain during physical activity or infusion provides an opportunistic, supplemental fuel. Available evidence indicates that lactate shuttling coupled to its local oxidation during activation is a small fraction of glucose oxidation. Developmental, experimental, and physiological context is critical for interpretation of metabolic studies in terms of theoretical models.
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