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Adekunbi DA, Huber HF, Li C, Nathanielsz PW, Cox LA, Salmon AB. Differential mitochondrial bioenergetics and cellular resilience in astrocytes, hepatocytes, and fibroblasts from aging baboons. GeroScience 2024:10.1007/s11357-024-01155-7. [PMID: 38607532 DOI: 10.1007/s11357-024-01155-7] [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: 02/06/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
Biological resilience, broadly defined as the ability to recover from an acute challenge and return to homeostasis, is of growing importance to the biology of aging. At the cellular level, there is variability across tissue types in resilience and these differences are likely to contribute to tissue aging rate disparities. However, there are challenges in addressing these cell-type differences at regional, tissue, and subject level. To address this question, we established primary cells from aged male and female baboons between 13.3 and 17.8 years spanning across different tissues, tissue regions, and cell types including (1) fibroblasts from skin and from the heart separated into the left ventricle (LV), right ventricle (RV), left atrium (LA), and right atrium (RA); (2) astrocytes from the prefrontal cortex and hippocampus; and (3) hepatocytes. Primary cells were characterized by their cell surface markers and their cellular respiration was assessed with Seahorse XFe96. Cellular resilience was assessed by modifying a live-cell imaging approach; we previously reported that monitors proliferation of dividing cells following response and recovery to oxidative (50 µM-H2O2), metabolic (1 mM-glucose), and proteostasis (0.1 µM-thapsigargin) stress. We noted significant differences even among similar cell types that are dependent on tissue source and the diversity in cellular response is stressor-specific. For example, astrocytes had a higher oxygen consumption rate and exhibited greater resilience to oxidative stress (OS) than both fibroblasts and hepatocytes. RV and RA fibroblasts were less resilient to OS compared with LV and LA, respectively. Skin fibroblasts were less impacted by proteostasis stress compared to astrocytes and cardiac fibroblasts. Future studies will test the functional relationship of these outcomes to the age and developmental status of donors as potential predictive markers.
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Affiliation(s)
- Daniel A Adekunbi
- Department of Molecular Medicine and Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA
| | - Hillary F Huber
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Cun Li
- Department of Animal Science, Texas Pregnancy and Life-Course Health Research Center, University of Wyoming, Laramie, WY, USA
| | - Peter W Nathanielsz
- Department of Animal Science, Texas Pregnancy and Life-Course Health Research Center, University of Wyoming, Laramie, WY, USA
| | - Laura A Cox
- Center for Precision Medicine, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Adam B Salmon
- Department of Molecular Medicine and Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA.
- Geriatric Research Education and Clinical Center, Audie L. Murphy Hospital, Southwest Veterans Health Care System, San Antonio, TX, USA.
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Vizuete AFK, Leal MB, Moreira AP, Seady M, Taday J, Gonçalves CA. Arundic acid (ONO-2506) downregulates neuroinflammation and astrocyte dysfunction after status epilepticus in young rats induced by Li-pilocarpine. Prog Neuropsychopharmacol Biol Psychiatry 2023; 123:110704. [PMID: 36565981 DOI: 10.1016/j.pnpbp.2022.110704] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 08/08/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Astrocytes, the most abundant glial cells, have several metabolic functions, including ionic, neurotransmitter and energetic homeostasis for neuronal activity. Reactive astrocytes and their dysfunction have been associated with several brain disorders, including the epileptogenic process. Glial Fibrillary Acidic Protein (GFAP) and S100 calcium-binding protein B (S100B) are astrocyte biomarkers associated with brain injury. We hypothesize that arundic acid (ONO-2506), which is known as an inhibitor of S100B synthesis and secretion, protects the hippocampal tissue from neuroinflammation and astrocyte dysfunction after status epileptics (SE) induction by Li-pilocarpine in young rats. Herein, we investigated the effects of arundic acid treatment, at time points of 6 or 24 h after the induction of SE by Li-pilocarpine, in young rats. In SE animals, arundic acid was able to prevent the damage induced by Li-pilocarpine in the hippocampus, decreasing neuroinflammatory signaling (reducing IL-1β, COX2, TLR4 and RAGE contents), astrogliosis (decreasing GFAP and S100B) and astrocytic dysfunction (recovering levels of GSH, glutamine synthetase and connexin-43). Furthermore, arundic acid improved glucose metabolism and reduced the glutamate excitotoxicity found in epilepsy. Our data reinforce the role of astrocytes in epileptogenesis development and the neuroprotective role of arundic acid, which modulates astrocyte function and neuroinflammation in SE animals.
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Affiliation(s)
- Adriana Fernanda K Vizuete
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil.
| | - Miriara B Leal
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil
| | - Ana Paula Moreira
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil
| | - Marina Seady
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil
| | - Jéssica Taday
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Laboratory of Calcium-Binding Proteins in CNS, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Pos Graduate Program in Biochemistry, Institute of Basic Health Sciences, UFRGS, Porto Alegre, RS, Brazil
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Abstract
To maintain energy supply to the brain, a direct energy source called adenosine triphosphate (ATP) is produced by oxidative phosphorylation and aerobic glycolysis of glucose in the mitochondria and cytoplasm. Brain glucose metabolism is reduced in many neurodegenerative diseases, including Alzheimer's disease (AD), where it appears presymptomatically in a progressive and region-specific manner. Following dysregulation of energy metabolism in AD, many cellular repair/regenerative processes are activated to conserve the energy required for cell viability. Glucose metabolism plays an important role in the pathology of AD and is closely associated with the tricarboxylic acid cycle, type 2 diabetes mellitus, and insulin resistance. The glucose intake in neurons is from endothelial cells, astrocytes, and microglia. Damage to neurocentric glucose also damages the energy transport systems in AD. Gut microbiota is necessary to modulate bidirectional communication between the gastrointestinal tract and brain. Gut microbiota may influence the process of AD by regulating the immune system and maintaining the integrity of the intestinal barrier. Furthermore, some therapeutic strategies have shown promising therapeutic effects in the treatment of AD at different stages, including the use of antidiabetic drugs, rescuing mitochondrial dysfunction, and epigenetic and dietary intervention. This review discusses the underlying mechanisms of alterations in energy metabolism in AD and provides potential therapeutic strategies in the treatment of AD.
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Pan SM, Zhou YF, Zuo N, Jiao RQ, Kong LD, Pan Y. Fluoxetine increases astrocytic glucose uptake and glycolysis in corticosterone-induced depression through restricting GR-TXNIP-GLUT1 Pathway. Front Pharmacol 2022; 13:872375. [PMID: 36105196 PMCID: PMC9465171 DOI: 10.3389/fphar.2022.872375] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022] Open
Abstract
Antidepressant fluoxetine can affect cerebral glucose metabolism in clinic, but the underlying molecular mechanism remains poorly understood. Here, we examined the effect of fluoxetine on brain regional glucose metabolism in a rat model of depression induced by repeated corticosterone injection, and explored the molecular mechanism. Fluoxetine was found to recover the decrease of 18F-fluorodeoxyglucose (18F-FDG) signal in prefrontal cortex (PFC), and increased 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG, a fluorescent glucose analog) uptake in an astrocyte-specific manner in ex vivo cultured PFC slices from corticosterone-induced depressive rats, which were consistent with its improvement of animal depressive behaviors. Furthermore, fluoxetine restricted nuclear translocation of glucocorticoid receptor (GR) to suppress the transcription of thioredoxin interacting protein (TXNIP). Subsequently, it promoted glucose transporter 1 (GLUT1)-mediated glucose uptake and glycolysis of PFC astrocytes through suppressing TXNIP expression under corticosterone-induced depressive state. More importantly, fluoxetine could improve glucose metabolism of corticosterone-stimulated astrocytes via TXNIP-GLUT1 pathway. These results demonstrated that fluoxetine increased astrocytic glucose uptake and glycolysis in corticosterone-induced depression via restricting GR-TXNIP-GLUT1 pathway. The modulation of astrocytic glucose metabolism by fluoxetine was suggested as a novel mechanism of its antidepressant action.
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Affiliation(s)
- Shu-Man Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Yi-Fan Zhou
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Na Zuo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Rui-Qing Jiao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu, China
- *Correspondence: Ling-Dong Kong, ; Ying Pan,
| | - Ying Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu, China
- *Correspondence: Ling-Dong Kong, ; Ying Pan,
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Tiwari AK, Adhikari A, Mishra LC, Srivastava A. Current Status of Our Understanding for Brain Integrated Functions and its Energetics. Neurochem Res 2022; 47:2499-2512. [PMID: 35689788 DOI: 10.1007/s11064-022-03633-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/07/2022] [Accepted: 05/09/2022] [Indexed: 10/18/2022]
Abstract
Human/animal brain is a unique organ with substantially high metabolism but it contains no energy reserve that is the reason it requires continuous supply of O2 and energy fluxes through CBF. The main source of energy remains glucose as the other biomolecules do not able to cross the blood-brain barrier. The speed of glucose metabolism is heterogeneous throughout the brain. One of the major flux consumption is Neuron-astrocyte cycling of glutamate and glutamine in glutamatergic neurons (approximately 80% of glucose metabolism in brain). The quantification of cellular glucose and other related substrate in resting, activated state can be analyzed through [18 F]FDG -positron-emission tomography (studying CMRglc) and [13 C/31P -MRS: for neuroenergetics & neurotransmitter cycling &31P-MRS: for energy induction & redox state). Merging basic in vitro studies with these techniques will help to develop new treatment paradigms for human brain diseased conditions.
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Affiliation(s)
- Anjani Kumar Tiwari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University (A Central University), 226025, Lucknow, Uttar Pradesh, India.
| | - Anupriya Adhikari
- Department of Chemistry, Babasaheb Bhimrao Ambedkar University (A Central University), 226025, Lucknow, Uttar Pradesh, India
| | - Lokesh Chandra Mishra
- Department of Zoology, Hansraj College, University of Delhi, North Campus, 110007, Delhi, India
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Rudayni HA, Stephenson G, Posterino GS. Measurements of basal d-glucose transport through GLUT1 across the intact plasma membrane of isolated segments from single fast- and slow-twitch skeletal muscle fibres of rat. Acta Physiol (Oxf) 2022; 234:e13789. [PMID: 35038771 PMCID: PMC9541404 DOI: 10.1111/apha.13789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 01/09/2022] [Accepted: 01/12/2022] [Indexed: 12/24/2022]
Abstract
Aim To develop a method for direct measurement of the fluorescent d‐glucose analogue 2‐NBDG transport across the plasma membrane of single skeletal muscle fibres and derive the theoretical framework for determining the kinetic parameters for d‐glucose transport under basal conditions. Methods A novel method is described for measuring free 2‐NBDG transport across plasma membrane of single rat muscle fibres at rest. The 2‐NBDG uptake was >90% suppressed by 100 µM cytochalasin B in both fast‐twitch and slow‐twitch fibres, indicating that the 2‐NBDG transport is GLUT‐mediated. Fibres were identified as fast‐twitch or slow‐twitch based on the differential sensitivity of their contractile apparatus to Sr2+. Results The time course of 2‐NBDG uptake in the presence of 50 µM 2‐NBDG follows a one‐phase exponential plateau curve and is faster in fast‐twitch (rate constant 0.053 ± 0.0024 s‐1) than in slow‐twitch fibres (rate constant 0.031 ± 0.0021 s‐1). The rate constants were markedly reduced in the presence of 20 mM d‐glucose to 0.0082 ± 0.0004 s‐1 and 0.0056 ± 0.0002 s‐1 in fast‐twitch and slow‐twitch fibres respectively. 2‐NBDG transport was asymmetric, consistent with GLUT1 being the major functional GLUT isoform transporting 2‐NBDG in muscle fibres at rest. The parameters describing the transport kinetics for both 2‐NBDG and d‐glucose (dissociation constants, Michaelis–Menten constants, maximal rates of uptake and outflow) were calculated from the measurements made with 2‐NBDG. Conclusion Free 2‐NBDG and d‐glucose transport across the plasma membrane of single rat muscle fibres at rest is fast, conclusively showing that the rate‐limiting step in d‐glucose uptake in skeletal muscle is not necessarily the GLUT‐mediated transport of d‐glucose.
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Affiliation(s)
- Hassan A. Rudayni
- Department of Biology College of Science Imam Mohammad Ibn Saud Islamic University Riyadh Saudi Arabia
| | - George Stephenson
- Department of Physiology, Anatomy and Microbiology La Trobe University Melbourne Victoria Australia
| | - Giuseppe S. Posterino
- Department of Physiology, Anatomy and Microbiology La Trobe University Melbourne Victoria Australia
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San Martín A, Arce-Molina R, Aburto C, Baeza-Lehnert F, Barros LF, Contreras-Baeza Y, Pinilla A, Ruminot I, Rauseo D, Sandoval PY. Visualizing physiological parameters in cells and tissues using genetically encoded indicators for metabolites. Free Radic Biol Med 2022; 182:34-58. [PMID: 35183660 DOI: 10.1016/j.freeradbiomed.2022.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/07/2023]
Abstract
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
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Affiliation(s)
- A San Martín
- Centro de Estudios Científicos (CECs), Valdivia, Chile.
| | - R Arce-Molina
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - C Aburto
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | | | - L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - Y Contreras-Baeza
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - A Pinilla
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile
| | - D Rauseo
- Centro de Estudios Científicos (CECs), Valdivia, Chile; Universidad Austral de Chile, Valdivia, Chile
| | - P Y Sandoval
- Centro de Estudios Científicos (CECs), Valdivia, Chile
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Clozapine induces astrocyte-dependent FDG-PET hypometabolism. Eur J Nucl Med Mol Imaging 2022; 49:2251-2264. [PMID: 35122511 DOI: 10.1007/s00259-022-05682-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/09/2022] [Indexed: 01/30/2023]
Abstract
PURPOSE Advances in functional imaging allowed us to visualize brain glucose metabolism in vivo and non-invasively with [18F]fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) imaging. In the past decades, FDG-PET has been instrumental in the understanding of brain function in health and disease. The source of the FDG-PET signal has been attributed to neuronal uptake, with hypometabolism being considered as a direct index of neuronal dysfunction or death. However, other brain cells are also metabolically active, including astrocytes. Based on the astrocyte-neuron lactate shuttle hypothesis, the activation of the glutamate transporter 1 (GLT-1) acts as a trigger for glucose uptake by astrocytes. With this in mind, we investigated glucose utilization changes after pharmacologically downregulating GLT-1 with clozapine (CLO), an anti-psychotic drug. METHODS Adult male Wistar rats (control, n = 14; CLO, n = 12) received CLO (25/35 mg kg-1) for 6 weeks. CLO effects were evaluated in vivo with FDG-PET and cortical tissue was used to evaluate glutamate uptake and GLT-1 and GLAST levels. CLO treatment effects were also assessed in cortical astrocyte cultures (glucose and glutamate uptake, GLT-1 and GLAST levels) and in cortical neuronal cultures (glucose uptake). RESULTS CLO markedly reduced in vivo brain glucose metabolism in several brain areas, especially in the cortex. Ex vivo analyses demonstrated decreased cortical glutamate transport along with GLT-1 mRNA and protein downregulation. In astrocyte cultures, CLO decreased GLT-1 density as well as glutamate and glucose uptake. By contrast, in cortical neuronal cultures, CLO did not affect glucose uptake. CONCLUSION This work provides in vivo demonstration that GLT-1 downregulation induces astrocyte-dependent cortical FDG-PET hypometabolism-mimicking the hypometabolic signature seen in people developing dementia-and adds further evidence that astrocytes are key contributors of the FDG-PET signal.
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Scavuzzo CJ, Newman LA, Gold PE, Korol DL. Time-dependent changes in hippocampal and striatal glycogen long after maze training in male rats. Neurobiol Learn Mem 2021; 185:107537. [PMID: 34634434 PMCID: PMC8672440 DOI: 10.1016/j.nlm.2021.107537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 09/09/2021] [Accepted: 10/04/2021] [Indexed: 12/20/2022]
Abstract
Long-lasting biological changes reflecting past experience have been studied in and typically attributed to neurons in the brain. Astrocytes, which are also present in large number in the brain, have recently been found to contribute critically to learning and memory processing. In the brain, glycogen is primarily found in astrocytes and is metabolized to lactate, which can be released from astrocytes. Here we report that astrocytes themselves have intrinsic neurochemical plasticity that alters the availability and provision of metabolic substrates long after an experience. Rats were trained to find food on one of two versions of a 4-arm maze: a hippocampus-sensitive place task and a striatum-sensitive response task. Remarkably, hippocampal glycogen content increased while striatal levels decreased during the 30 days after rats were trained to find food in the place version, but not the response version, of the maze tasks. A long-term consequence of the durable changes in glycogen stores was seen in task-by-site differences in extracellular lactate responses activated by testing on a working memory task administered 30 days after initial training, the time when differences in glycogen content were most robust. These results suggest that astrocytic plasticity initiated by a single experience may augment future availability of energy reserves, perhaps priming brain areas to process learning of subsequent experiences more effectively.
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Affiliation(s)
- Claire J Scavuzzo
- Department of Psychology, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
| | - Lori A Newman
- Psychological Science Department, Vassar College, 124 Raymond Avenue, Box 713, Poughkeepsie, NY 12604, USA
| | - Paul E Gold
- Biology Department, Syracuse University, Syracuse, NY 13244, USA
| | - Donna L Korol
- Biology Department, Syracuse University, Syracuse, NY 13244, USA.
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Cleland NRW, Al-Juboori SI, Dobrinskikh E, Bruce KD. Altered substrate metabolism in neurodegenerative disease: new insights from metabolic imaging. J Neuroinflammation 2021; 18:248. [PMID: 34711251 PMCID: PMC8555332 DOI: 10.1186/s12974-021-02305-w] [Citation(s) in RCA: 21] [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: 08/11/2021] [Accepted: 10/21/2021] [Indexed: 12/13/2022] Open
Abstract
Neurodegenerative diseases (NDs), such as Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS), are relatively common and devastating neurological disorders. For example, there are 6 million individuals living with AD in the United States, a number that is projected to grow to 14 million by the year 2030. Importantly, AD, PD and MS are all characterized by the lack of a true disease-modifying therapy that is able to reverse or halt disease progression. In addition, the existing standard of care for most NDs only addresses the symptoms of the disease. Therefore, alternative strategies that target mechanisms underlying the neuropathogenesis of disease are much needed. Recent studies have indicated that metabolic alterations in neurons and glia are commonly observed in AD, PD and MS and lead to changes in cell function that can either precede or protect against disease onset and progression. Specifically, single-cell RNAseq studies have shown that AD progression is tightly linked to the metabolic phenotype of microglia, the key immune effector cells of the brain. However, these analyses involve removing cells from their native environment and performing measurements in vitro, influencing metabolic status. Therefore, technical approaches that can accurately assess cell-specific metabolism in situ have the potential to be transformative to our understanding of the mechanisms driving AD. Here, we review our current understanding of metabolism in both neurons and glia during homeostasis and disease. We also evaluate recent advances in metabolic imaging, and discuss how emerging modalities, such as fluorescence lifetime imaging microscopy (FLIM) have the potential to determine how metabolic perturbations may drive the progression of NDs. Finally, we propose that the temporal, regional, and cell-specific characterization of brain metabolism afforded by FLIM will be a critical first step in the rational design of metabolism-focused interventions that delay or even prevent NDs.
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Affiliation(s)
- Nicholas R W Cleland
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
- School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Saif I Al-Juboori
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Evgenia Dobrinskikh
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, USA
- Division of Pulmonary Sciences and Critical Care, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA
| | - Kimberley D Bruce
- Endocrinology, Metabolism and Diabetes, Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA.
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Astrocyte Gliotransmission in the Regulation of Systemic Metabolism. Metabolites 2021; 11:metabo11110732. [PMID: 34822390 PMCID: PMC8623475 DOI: 10.3390/metabo11110732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/28/2022] Open
Abstract
Normal brain function highly relies on the appropriate functioning of astrocytes. These glial cells are strategically situated between blood vessels and neurons, provide significant substrate support to neuronal demand, and are sensitive to neuronal activity and energy-related molecules. Astrocytes respond to many metabolic conditions and regulate a wide array of physiological processes, including cerebral vascular remodeling, glucose sensing, feeding, and circadian rhythms for the control of systemic metabolism and behavior-related responses. This regulation ultimately elicits counterregulatory mechanisms in order to couple whole-body energy availability with brain function. Therefore, understanding the role of astrocyte crosstalk with neighboring cells via the release of molecules, e.g., gliotransmitters, into the parenchyma in response to metabolic and neuronal cues is of fundamental relevance to elucidate the distinct roles of these glial cells in the neuroendocrine control of metabolism. Here, we review the mechanisms underlying astrocyte-released gliotransmitters that have been reported to be crucial for maintaining homeostatic regulation of systemic metabolism.
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Pan SM, Pan Y, Tang YL, Zuo N, Zhang YX, Jia KK, Kong LD. Thioredoxin interacting protein drives astrocytic glucose hypometabolism in corticosterone-induced depressive state. J Neurochem 2021; 161:84-100. [PMID: 34368959 DOI: 10.1111/jnc.15489] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/30/2021] [Accepted: 08/04/2021] [Indexed: 01/18/2023]
Abstract
Brain energetics disturbance is a hypothesized cause of depression. Glucose is the predominant fuel of brain energy metabolism, however, the cell-specific change of glucose metabolism and underlying molecular mechanism in depression remain unclear. In this study, we firstly applied 18 F-FDG PET and observed brain glucose hypometabolism in prefrontal cortex (PFC) of corticosterone-induced depression of rats. Next, astrocytic glucose hypometabolism was identified in PFC slices in in both corticosterone-induced depression of rats and cultured primary astrocytes from newborn rat PFC after stress-level corticosterone (100 nM) stimulation. Furthermore, we found the blockage of glucose uptake and the decrease of plasma membrane (PM) translocation of glucose transporter 1 (GLUT1) in astrocytic glucose hypometabolism under depressive condition. Interestingly, thioredoxin interacting protein (TXNIP), a glucose metabolism sensor and controller, was found to be overexpressed in corticosterone-stimulated astrocytes in vivo and in vitro. High TXNIP level could restrict GLUT1-mediated glucose uptake in primary astrocytes in vitro. Adeno-associated virus vector-mediated astrocytic TXNIP overexpression in rat medial PFC suppressed GLUT1 PM translocation, consequently developed depressive-like behavior. Conversely, TXNIP siRNA facilitated GLUT1 PM translocation to recover glucose hypometabolism in corticosterone-exposed cultured astrocytes. Notably, astrocyte-specific knockdown of TXNIP in medial PFC of rats facilitated astrocytic GLUT1 PM translocation, showing obvious antidepressant activity. These findings provide a new astrocytic energetic perspective in the pathogenesis of depression, more importantly, provide TXNIP as a promising molecular target for novel depression therapy.
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Affiliation(s)
- Shu-Man Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ying Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ya-Li Tang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Na Zuo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Yan-Xiu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ke-Ke Jia
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu Province, P. R. China
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13
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Astrocyte Networks as Therapeutic Targets in Glaucomatous Neurodegeneration. Cells 2021; 10:cells10061368. [PMID: 34199470 PMCID: PMC8228804 DOI: 10.3390/cells10061368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/28/2021] [Accepted: 05/30/2021] [Indexed: 11/22/2022] Open
Abstract
Astrocytes are intimately involved in the response to neurodegenerative stress and have become an attractive target for the development of neuroprotective therapies. However, studies often focus on astrocytes as single-cell units. Astrocytes are densely interconnected by gap junctions that are composed primarily of the protein connexin-43 (Cx43) and can function as a broader network of cells. Such networks contribute to a number of important processes, including metabolite distribution and extracellular ionic buffering, and are likely to play an important role in the progression of neurodegenerative disease. This review will focus on the pro-degenerative and pro-survival influence of astrocyte Cx43 in disease progression, with a focus on the roles of gap junctions and hemichannels in the spread of degenerative stress. Finally, we will highlight the specific evidence for targeting these networks in the treatment of glaucomatous neurodegeneration and other optic neuropathies.
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14
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Viegas FO, Neuhauss SCF. A Metabolic Landscape for Maintaining Retina Integrity and Function. Front Mol Neurosci 2021; 14:656000. [PMID: 33935647 PMCID: PMC8081888 DOI: 10.3389/fnmol.2021.656000] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/22/2021] [Indexed: 01/27/2023] Open
Abstract
Neurons have high metabolic demands that are almost exclusively met by glucose supplied from the bloodstream. Glucose is utilized in complex metabolic interactions between neurons and glia cells, described by the astrocyte-neuron lactate shuttle (ANLS) hypothesis. The neural retina faces similar energy demands to the rest of the brain, with additional high anabolic needs to support continuous renewal of photoreceptor outer segments. This demand is met by a fascinating variation of the ANLS in which photoreceptors are the central part of a metabolic landscape, using glucose and supplying surrounding cells with metabolic intermediates. In this review we summarize recent evidence on how neurons, in particular photoreceptors, meet their energy and biosynthetic requirements by comprising a metabolic landscape of interdependent cells.
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Affiliation(s)
- Filipe O Viegas
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Life Science Zurich Graduate School, Ph.D. Program in Molecular Life Sciences, Zurich, Switzerland
| | - Stephan C F Neuhauss
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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15
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Hanani M, Verkhratsky A. Satellite Glial Cells and Astrocytes, a Comparative Review. Neurochem Res 2021; 46:2525-2537. [PMID: 33523395 DOI: 10.1007/s11064-021-03255-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022]
Abstract
Astroglia are neural cells, heterogeneous in form and function, which act as supportive elements of the central nervous system; astrocytes contribute to all aspects of neural functions in health and disease. Through their highly ramified processes, astrocytes form close physical contacts with synapses and blood vessels, and are integrated into functional syncytia by gap junctions. Astrocytes interact among themselves and with other cells types (e.g., neurons, microglia, blood vessel cells) by an elaborate repertoire of chemical messengers and receptors; astrocytes also influence neural plasticity and synaptic transmission through maintaining homeostasis of neurotransmitters, K+ buffering, synaptic isolation and control over synaptogenesis and synaptic elimination. Satellite glial cells (SGCs) are the most abundant glial cells in sensory ganglia, and are believed to play major roles in sensory functions, but so far research into SGCs attracted relatively little attention. In this review we compare SGCs to astrocytes with the purpose of using the vast knowledge on astrocytes to explore new aspects of SGCs. We survey the main properties of these two cells types and highlight similarities and differences between them. We conclude that despite the much greater diversity in morphology and signaling mechanisms of astrocytes, there are some parallels between them and SGCs. Both types serve as boundary cells, separating different compartments in the nervous system, but much more needs to be learned on this aspect of SGCs. Astrocytes and SGCs employ chemical messengers and calcium waves for intercellular signaling, but their significance is still poorly understood for both cell types. Both types undergo major changes under pathological conditions, which have a protective function, but an also contribute to disease, and chronic pain in particular. The knowledge obtained on astrocytes is likely to benefit future research on SGCs.
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Affiliation(s)
- Menachem Hanani
- Laboratory of Experimental Surgery, Hadassah-Hebrew University Medical Center and Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.,Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain
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16
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Rose J, Brian C, Pappa A, Panayiotidis MI, Franco R. Mitochondrial Metabolism in Astrocytes Regulates Brain Bioenergetics, Neurotransmission and Redox Balance. Front Neurosci 2020; 14:536682. [PMID: 33224019 PMCID: PMC7674659 DOI: 10.3389/fnins.2020.536682] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 10/14/2020] [Indexed: 01/17/2023] Open
Abstract
In the brain, mitochondrial metabolism has been largely associated with energy production, and its dysfunction is linked to neuronal cell loss. However, the functional role of mitochondria in glial cells has been poorly studied. Recent reports have demonstrated unequivocally that astrocytes do not require mitochondria to meet their bioenergetics demands. Then, the question remaining is, what is the functional role of mitochondria in astrocytes? In this work, we review current evidence demonstrating that mitochondrial central carbon metabolism in astrocytes regulates overall brain bioenergetics, neurotransmitter homeostasis and redox balance. Emphasis is placed in detailing carbon source utilization (glucose and fatty acids), anaplerotic inputs and cataplerotic outputs, as well as carbon shuttles to neurons, which highlight the metabolic specialization of astrocytic mitochondria and its relevance to brain function.
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Affiliation(s)
- Jordan Rose
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, United States.,School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Christian Brian
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, United States.,School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Aglaia Pappa
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Mihalis I Panayiotidis
- Department of Electron Microscopy & Molecular Pathology, Cyprus Institute of Neurology & Genetics, Nicosia, Cyprus
| | - Rodrigo Franco
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, United States.,School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
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17
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Abstract
Astrocytes, initially described as merely support cells, are now known as a heterogeneous population of cells actively involved in a variety of biological functions such as: neuronal migration and differentiation; regulation of cerebral blood flow; metabolic control of extracellular potassium concentration; and modulation of synapse formation and elimination; among others. Cerebellar glial cells have been shown to play a significant role in proliferation, differentiation, migration, and synaptogenesis. However, less evidence is available about the role of neuron-astrocyte interactions during cerebellar development and their impact on diseases of the cerebellum. In this review, we will focus on the mechanisms underlying cellular interactions, specifically neuron-astrocyte interactions, during cerebellar development, function, and disease. We will discuss how cerebellar glia, astrocytes, and Bergmann glia play a fundamental role in several steps of cerebellar development, such as granule cell migration, axonal growth, neuronal differentiation, and synapse formation, and in diseases associated with the cerebellum. We will focus on how astrocytes and thyroid hormones impact cerebellar development. Furthermore, we will provide evidence of how growth factors secreted by glial cells, such as epidermal growth factor and transforming growth factors, control cerebellar organogenesis. Finally, we will argue that glia are a key mediator of cerebellar development and that identification of molecules and pathways involved in neuron-glia interactions may contribute to a better understanding of cerebellar development and associated disorders.
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18
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Takahashi S. Metabolic compartmentalization between astroglia and neurons in physiological and pathophysiological conditions of the neurovascular unit. Neuropathology 2020; 40:121-137. [PMID: 32037635 PMCID: PMC7187297 DOI: 10.1111/neup.12639] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 12/17/2022]
Abstract
Astroglia or astrocytes, the most abundant cells in the brain, are interposed between neuronal synapses and microvasculature in the brain gray matter. They play a pivotal role in brain metabolism as well as in the regulation of cerebral blood flow, taking advantage of their unique anatomical location. In particular, the astroglial cellular metabolic compartment exerts supportive roles in dedicating neurons to the generation of action potentials and protects them against oxidative stress associated with their high energy consumption. An impairment of normal astroglial function, therefore, can lead to numerous neurological disorders including stroke, neurodegenerative diseases, and neuroimmunological diseases, in which metabolic derangements accelerate neuronal damage. The neurovascular unit (NVU), the major components of which include neurons, microvessels, and astroglia, is a conceptual framework that was originally used to better understand the pathophysiology of cerebral ischemia. At present, the NVU is a tool for understanding normal brain physiology as well as the pathophysiology of numerous neurological disorders. The metabolic responses of astroglia in the NVU can be either protective or deleterious. This review focuses on three major metabolic compartments: (i) glucose and lactate; (ii) fatty acid and ketone bodies; and (iii) D- and L-serine. Both the beneficial and the detrimental roles of compartmentalization between neurons and astroglia will be discussed. A better understanding of the astroglial metabolic response in the NVU is expected to lead to the development of novel therapeutic strategies for diverse neurological diseases.
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Affiliation(s)
- Shinichi Takahashi
- Department of Neurology and StrokeSaitama Medical University International Medical CenterSaitamaJapan
- Department of PhysiologyKeio University School of MedicineTokyoJapan
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19
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L-Glucose: Another Path to Cancer Cells. Cancers (Basel) 2020; 12:cancers12040850. [PMID: 32244695 PMCID: PMC7225996 DOI: 10.3390/cancers12040850] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/24/2020] [Accepted: 03/30/2020] [Indexed: 01/31/2023] Open
Abstract
Cancerous tumors comprise cells showing metabolic heterogeneity. Among numerous efforts to understand this property, little attention has been paid to the possibility that cancer cells take up and utilize otherwise unusable substrates as fuel. Here we discuss this issue by focusing on l-glucose, the mirror image isomer of naturally occurring d-glucose; l-glucose is an unmetabolizable sugar except in some bacteria. By combining relatively small fluorophores with l-glucose, we generated fluorescence-emitting l-glucose tracers (fLGs). To our surprise, 2-NBDLG, one of these fLGs, which we thought to be merely a control substrate for the fluorescent d-glucose tracer 2-NBDG, was specifically taken up into tumor cell aggregates (spheroids) that exhibited nuclear heterogeneity, a major cytological feature of malignancy in cancer diagnosis. Changes in mitochondrial activity were also associated with the spheroids taking up fLG. To better understand these phenomena, we review here the Warburg effect as well as key studies regarding glucose uptake. We also discuss tumor heterogeneity involving aberrant uptake of glucose and mitochondrial changes based on the data obtained by fLG. We then consider the use of fLGs as novel markers for visualization and characterization of malignant tumor cells.
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20
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Alambyan V, Pace J, Sukpornchairak P, Yu X, Alnimir H, Tatton R, Chitturu G, Yarlagadda A, Ramos-Estebanez C. Imaging Guidance for Therapeutic Delivery: The Dawn of Neuroenergetics. Neurotherapeutics 2020; 17:522-538. [PMID: 32240530 PMCID: PMC7283376 DOI: 10.1007/s13311-020-00843-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Modern neurocritical care relies on ancillary diagnostic testing in the form of multimodal monitoring to address acute changes in the neurological homeostasis. Much of our armamentarium rests upon physiological and biochemical surrogates of organ or regional level metabolic activity, of which a great deal is invested at the metabolic-hemodynamic-hydrodynamic interface to rectify the traditional intermediaries of glucose consumption. Despite best efforts to detect cellular neuroenergetics, current modalities cannot appreciate the intricate coupling between astrocytes and neurons. Invasive monitoring is not without surgical complication, and noninvasive strategies do not provide an adequate spatial or temporal resolution. Without knowledge of the brain's versatile behavior in specific metabolic states (glycolytic vs oxidative), clinical practice would lag behind laboratory empiricism. Noninvasive metabolic imaging represents a new hope in delineating cellular, nigh molecular level energy exchange to guide targeted management in a diverse array of neuropathology.
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Affiliation(s)
- Vilakshan Alambyan
- Department of Neurology, Albert Einstein Medical Center, Philadelphia, Pennsylvania, USA
| | - Jonathan Pace
- Neurological Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Persen Sukpornchairak
- Neurological Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Hamza Alnimir
- Neurological Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ryan Tatton
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Gautham Chitturu
- Department of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Anisha Yarlagadda
- Department of Arts and Sciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ciro Ramos-Estebanez
- Neurological Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
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21
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Staricha K, Meyers N, Garvin J, Liu Q, Rarick K, Harder D, Cohen S. Effect of high glucose condition on glucose metabolism in primary astrocytes. Brain Res 2020; 1732:146702. [PMID: 32032612 DOI: 10.1016/j.brainres.2020.146702] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 01/29/2020] [Accepted: 02/03/2020] [Indexed: 12/23/2022]
Abstract
In the brain, glucose enters astrocytes through glucose transporter (GLUT1) and either enters glycolysis or the glycogen shunt. Astrocytes meet the energy needs of neurons by building up and breaking down their glycogen supply. High glucose exposure causes astrocyte dysregulation, but its effects on glucose metabolism are relatively unknown. We hypothesized that high glucose conditioning induces a glycogenic state in the astrocyte, resulting in an inefficient mobilization of substrates when challenged with glucose deprivation. Using neonatal rat astrocytes, we used normal glucose (NG, 5.5 mM) vs. high glucose (HG, 25 mM) feeding media and measured cell membrane GLUT1 expression, glucose analog uptake, glycogen content, and cellular bioenergetics. This study demonstrates that HG conditioning causes increased glucose analog uptake (p < 0.05) without affecting GLUT1 membrane expression when compared to NG conditioned astrocytes. Increased glucose uptake in HG astrocytes is associated with higher baseline glycogen content compared to NG exposed astrocytes (p < 0.05). When challenged with glucose deprivation, HG astrocytes break down more than double the amount of glycogen molecules compared to NG astrocytes, although they break down a similar percentage of the starting glycogen stores (NG = 62%, HG = 55%). Additionally, HG conditioning negatively impacts astrocyte maximal respiration and glycolytic reserve capacity assessed by the Seahorse mitochondrial stress test and glycolytic stress test, respectively (p < 0.05). These results suggest that HG conditioning shifts astrocytes towards glycogen storage at baseline. Despite increased glycogen storage, HG astrocytes demonstrate decreased metabolic efficiency and capacity putting them at higher risk during extended periods of glucose deprivation.
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Affiliation(s)
- Kelly Staricha
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - Nicholas Meyers
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - Jodi Garvin
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - Qiuli Liu
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - Kevin Rarick
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - David Harder
- Department of Physiology, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States
| | - Susan Cohen
- Department of Pediatrics, Medical College of Wisconsin, 8701 W Watertown Plank Rd, Wauwatosa, WI 53226, United States.
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22
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Beiersdorfer A, Wolburg H, Grawe J, Scheller A, Kirchhoff F, Lohr C. Sublamina-specific organization of the blood brain barrier in the mouse olfactory nerve layer. Glia 2019; 68:631-645. [PMID: 31696993 DOI: 10.1002/glia.23744] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 01/19/2023]
Abstract
Astrocytes constitute the main glial component of the mammalian blood brain barrier (BBB). However, in the olfactory bulb (OB), the olfactory nerve layer (ONL) is almost devoid of astrocytes, raising the question which glial cells are part of the BBB. We used mice expressing EGFP in astrocytes and tdTomato in olfactory ensheathing cells (OECs), a specialized type of glial cells in the ONL, to unequivocally identify both glial cell types and investigate their contribution to the BBB in the olfactory bulb. OECs were located exclusively in the ONL, while somata of astrocytes were located in deeper layers and extended processes in the inner sublamina of the ONL. These processes surrounded blood vessels and contained aquaporin-4, an astrocytic protein enriched at the BBB. In the outer sublamina of the ONL, in contrast, blood vessels were surrounded by aquaporin-4-negative processes of OECs. Transcardial perfusion of blood vessels with lanthanum and subsequent visualization by electron microscopy showed that blood vessels enwrapped by OECs possessed intact tight junctions. In acute olfactory bulb preparations, injection of fluorescent glucose 6-NBDG into blood vessels resulted in labeling of OECs, indicating glucose transport from the perivascular space into OECs. In addition, Ca2+ transients in OECs in the outer sublamina evoked vasoconstriction, whereas Ca2+ signaling in OECs of the inner sublamina had no effect on adjacent blood vessels. Our results demonstrate that the BBB in the inner sublamina of the ONL contains astrocytes, while in the outer ONL OECs are part of the BBB.
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Affiliation(s)
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, University of Tübingen, Tübingen, Germany
| | - Janine Grawe
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Christian Lohr
- Division of Neurophysiology, University of Hamburg, Hamburg, Germany
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23
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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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24
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Ruminot I, Schmälzle J, Leyton B, Barros LF, Deitmer JW. Tight coupling of astrocyte energy metabolism to synaptic activity revealed by genetically encoded FRET nanosensors in hippocampal tissue. J Cereb Blood Flow Metab 2019; 39:513-523. [PMID: 29083247 PMCID: PMC6421254 DOI: 10.1177/0271678x17737012] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 11/17/2022]
Abstract
The potassium ion, K+, a neuronal signal that is released during excitatory synaptic activity, produces acute activation of glucose consumption in cultured astrocytes, a phenomenon mediated by the sodium bicarbonate cotransporter NBCe1 ( SLC4A4). We have explored here the relevance of this mechanism in brain tissue by imaging the effect of neuronal activity on pH, glucose, pyruvate and lactate dynamics in hippocampal astrocytes using BCECF and FRET nanosensors. Electrical stimulation of Schaffer collaterals produced fast activation of glucose consumption in astrocytes with a parallel increase in intracellular pyruvate and biphasic changes in lactate . These responses were blocked by TTX and were absent in tissue slices prepared from NBCe1-KO mice. Direct depolarization of astrocytes with elevated extracellular K+ or Ba2+ mimicked the metabolic effects of electrical stimulation. We conclude that the glycolytic pathway of astrocytes in situ is acutely sensitive to neuronal activity, and that extracellular K+ and the NBCe1 cotransporter are involved in metabolic crosstalk between neurons and astrocytes. Glycolytic activation of astrocytes in response to neuronal K+ helps to provide an adequate supply of lactate, a metabolite that is released by astrocytes and which acts as neuronal fuel and an intercellular signal.
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Affiliation(s)
- Iván Ruminot
- Abteilung für Allgemeine Zoologie, FB
Biologie, University of Kaiserslautern, Germany
- Centro de Estudios Científicos (CECs),
Valdivia, Chile
| | - Jana Schmälzle
- Abteilung für Allgemeine Zoologie, FB
Biologie, University of Kaiserslautern, Germany
| | - Belén Leyton
- Centro de Estudios Científicos (CECs),
Valdivia, Chile
- Universidad Austral de Chile, Valdivia,
Chile
| | | | - Joachim W Deitmer
- Abteilung für Allgemeine Zoologie, FB
Biologie, University of Kaiserslautern, Germany
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25
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Aerobic Glycolysis Is Required for Spatial Memory Acquisition But Not Memory Retrieval in Mice. eNeuro 2019; 6:eN-NWR-0389-18. [PMID: 30809587 PMCID: PMC6390195 DOI: 10.1523/eneuro.0389-18.2019] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/23/2019] [Accepted: 01/26/2019] [Indexed: 12/18/2022] Open
Abstract
The consolidation of newly formed memories and their retrieval are energetically demanding processes. Aerobic glycolysis (AG), also known as the Warburg effect, consists of the production of lactate from glucose in the presence of oxygen. The astrocyte neuron lactate shuttle hypothesis posits that astrocytes process glucose by AG to generate lactate, which is used as a fuel source within neurons to maintain synaptic activity. Studies in mice have demonstrated that lactate transport between astrocytes and neurons is required for long-term memory formation, yet the role of lactate production in memory acquisition and retrieval has not previously been explored. Here, we examined the effect of dichloroacetate (DCA), a chemical inhibitor of lactate production, on spatial learning and memory in mice using the Morris water maze (MWM). In vivo hyperpolarized 13C-pyruvate magnetic resonance spectroscopy revealed decreased conversion of pyruvate to lactate in the mouse brain following DCA administration, concomitant with a reduction in the phosphorylation of pyruvate dehydrogenase. DCA exposure before each training session in the MWM impaired learning, which subsequently resulted in impaired memory during the probe trial. In contrast, mice that underwent training without DCA exposure, but received a single DCA injection before the probe trial exhibited normal memory. Our findings indicate that AG plays a key role during memory acquisition but is less important for the retrieval of established memories. Thus, the activation of AG may be important for learning-dependent synaptic plasticity rather than the activation of signaling cascades required for memory retrieval.
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26
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Takado Y, Cheng T, Bastiaansen JAM, Yoshihara HAI, Lanz B, Mishkovsky M, Lengacher S, Comment A. Hyperpolarized 13C Magnetic Resonance Spectroscopy Reveals the Rate-Limiting Role of the Blood-Brain Barrier in the Cerebral Uptake and Metabolism of l-Lactate in Vivo. ACS Chem Neurosci 2018; 9:2554-2562. [PMID: 29771492 PMCID: PMC6119468 DOI: 10.1021/acschemneuro.8b00066] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The dynamics of l-lactate transport across the blood-brain barrier (BBB) and its cerebral metabolism are still subject to debate. We studied lactate uptake and intracellular metabolism in the mouse brain using hyperpolarized 13C magnetic resonance spectroscopy (MRS). Following the intravenous injection of hyperpolarized [1-13C]lactate, we observed that the distribution of the 13C label between lactate and pyruvate, which has been shown to be representative of their pool size ratio, is different in NMRI and C57BL/6 mice, the latter exhibiting a higher level of cerebral lactate dehydrogenase A ( Ldha) expression. On the basis of this observation, and an additional set of experiments showing that the cerebral conversion of [1-13C]lactate to [1-13C]pyruvate increases after exposing the brain to ultrasound irradiation that reversibly opens the BBB, we concluded that lactate transport is rate-limited by the BBB, with a 30% increase in lactate uptake after its disruption. It was also deduced from these results that hyperpolarized 13C MRS can be used to detect a variation in cerebral lactate uptake of <40 nmol in a healthy brain during an in vivo experiment lasting only 75 s, opening new opportunities to study the role of lactate in brain metabolism.
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Affiliation(s)
- Yuhei Takado
- Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Department of Functional Brain Imaging Research, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tian Cheng
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, United Kingdom
| | - Jessica A. M. Bastiaansen
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Department of Radiology, University Hospital Lausanne (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Hikari A. I. Yoshihara
- Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Bernard Lanz
- Sir Peter Mansfield Magnetic Resonance Center, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Mor Mishkovsky
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Sylvain Lengacher
- Laboratory of Neuroenergetics and Cellular Dynamics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Arnaud Comment
- Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- General Electric Healthcare, Chalfont St Giles, Buckinghamshire HP8 4SP, United Kingdom
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27
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Lu WT, Sun SQ, Li Y, Xu SY, Gan SW, Xu J, Qiu GP, Zhuo F, Huang SQ, Jiang XL, Huang J. Curcumin Ameliorates Memory Deficits by Enhancing Lactate Content and MCT2 Expression in APP/PS1 Transgenic Mouse Model of Alzheimer's Disease. Anat Rec (Hoboken) 2018; 302:332-338. [PMID: 30312017 DOI: 10.1002/ar.23969] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 05/01/2018] [Accepted: 06/03/2018] [Indexed: 12/16/2022]
Abstract
Curcumin is a natural product with several anti-Alzheimer's disease (AD) neuroprotective properties. This study aimed to investigate the effects of curcumin on memory deficits, lactate content, and monocarboxylate transporter 2 (MCT2) in APP/PS1 mouse model of AD. APP/PS1 transgenic mice and wild-type (WT) C57BL/6J mice were used in the present study. Spatial learning and memory of the mice was detected using Morris water-maze test. Cerebral cortex and hippocampus lactate contents were detected using lactate assay. MCT2 expression in the cerebral cortex and hippocampus was examined by immunohistochemistry and Western blotting. Results showed that spatial learning and memory deficits were improved in curcumin-treated APP/PS1 mouse group compared with those in APP/PS1 mice group. Brain lactate content and MCT2 protein level were increased in curcumin-treated APP/PS1 mice than in APP/PS1 mice. In summary, our findings indicate that curcumin could ameliorate memory impairments in APP/PS1 mouse model of AD. This phenomenon may be at least partially due to its improving effect on the lactate content and MCT2 protein expression in the brain. Anat Rec, 302:332-338, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Wei-Tian Lu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
| | - Shan-Quan Sun
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
| | - Yu Li
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China
| | - Shi-Ye Xu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
| | - Sheng-Wei Gan
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
| | - Jin Xu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
| | - Guo-Ping Qiu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China
| | - Fei Zhuo
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China
| | - Si-Qin Huang
- Traditional Chinese Medicine College, Chongqing Medical University, Chongqing, 40016, China
| | - Xu-Li Jiang
- Department of Anatomy, Science and Technology College of Hubei University for Nationalities, Enshi, 445000, China
| | - Juan Huang
- Institute of Neuroscience, Chongqing Medical University, Chongqing, 40016, China.,Department of Anatomy, Chongqing Medical University, Chongqing, 40016, China
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28
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Nuñez MT, Chana-Cuevas P. New Perspectives in Iron Chelation Therapy for the Treatment of Neurodegenerative Diseases. Pharmaceuticals (Basel) 2018; 11:ph11040109. [PMID: 30347635 PMCID: PMC6316457 DOI: 10.3390/ph11040109] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 02/07/2023] Open
Abstract
Iron chelation has been introduced as a new therapeutic concept for the treatment of neurodegenerative diseases with features of iron overload. At difference with iron chelators used in systemic diseases, effective chelators for the treatment of neurodegenerative diseases must cross the blood–brain barrier. Given the promissory but still inconclusive results obtained in clinical trials of iron chelation therapy, it is reasonable to postulate that new compounds with properties that extend beyond chelation should significantly improve these results. Desirable properties of a new generation of chelators include mitochondrial destination, the center of iron-reactive oxygen species interaction, and the ability to quench free radicals produced by the Fenton reaction. In addition, these chelators should have moderate iron binding affinity, sufficient to chelate excessive increments of the labile iron pool, estimated in the micromolar range, but not high enough to disrupt physiological iron homeostasis. Moreover, candidate chelators should have selectivity for the targeted neuronal type, to lessen unwanted secondary effects during long-term treatment. Here, on the basis of a number of clinical trials, we discuss critically the current situation of iron chelation therapy for the treatment of neurodegenerative diseases with an iron accumulation component. The list includes Parkinson’s disease, Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration, Huntington disease and Alzheimer’s disease. We also review the upsurge of new multifunctional iron chelators that in the future may replace the conventional types as therapeutic agents for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Marco T Nuñez
- Faculty of Sciences, Universidad de Chile, Las Palmeras 3425, Santiago 7800024, Chile.
| | - Pedro Chana-Cuevas
- Center for the Treatment of Movement Disorders, Universidad de Santiago de Chile, Belisario Prat 1597, Santiago 83800000, Chile.
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29
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Li W, Roy Choudhury G, Winters A, Prah J, Lin W, Liu R, Yang SH. Hyperglycemia Alters Astrocyte Metabolism and Inhibits Astrocyte Proliferation. Aging Dis 2018; 9:674-684. [PMID: 30090655 PMCID: PMC6065301 DOI: 10.14336/ad.2017.1208] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 12/08/2017] [Indexed: 12/01/2022] Open
Abstract
Diabetes milieu is a complex metabolic disease that has been known to associate with high risk of various neurological disorders. Hyperglycemia in diabetes could dramatically increase neuronal glucose levels which leads to neuronal damage, a phenomenon referred to as glucose neurotoxicity. On the other hand, the impact of hyperglycemia on astrocytes has been less explored. Astrocytes play important roles in brain energy metabolism through neuron-astrocyte coupling. As the component of blood brain barrier, glucose might be primarily transported into astrocytes, hence, impose direct impact on astrocyte metabolism and function. In the present study, we determined the effect of high glucose on the energy metabolism and function of primary astrocytes. Hyperglycemia level glucose (25 mM) induced cell cycle arrest and inhibited proliferation and migration of primary astrocytes. Consistently, high glucose decreased cyclin D1 and D3 expression. High glucose enhanced glycolytic metabolism, increased ATP and glycogen content in primary astrocytes. In addition, high glucose activated AMP-activated protein kinase (AMPK) signaling pathway in astrocytes. In summary, our in vitro study indicated that hyperglycemia might impact astrocyte energy metabolism and function phenotype. Our study provides a potential mechanism which may underlie the diabetic cerebral neuropathy and warrant further in vivo study to determine the effect of hyperglycemia on astrocyte metabolism and function.
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Affiliation(s)
- Wenjun Li
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Gourav Roy Choudhury
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Ali Winters
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Jude Prah
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Wenping Lin
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.,2Department of Orthopedic Surgery, The Second Affiliated Hospital, Fujian Medical University, Fujian Province, 362000, China
| | - Ran Liu
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Shao-Hua Yang
- 1Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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30
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Finelli MJ, Paramo T, Pires E, Ryan BJ, Wade-Martins R, Biggin PC, McCullagh J, Oliver PL. Oxidation Resistance 1 Modulates Glycolytic Pathways in the Cerebellum via an Interaction with Glucose-6-Phosphate Isomerase. Mol Neurobiol 2018; 56:1558-1577. [PMID: 29905912 PMCID: PMC6368252 DOI: 10.1007/s12035-018-1174-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/01/2018] [Indexed: 12/13/2022]
Abstract
Glucose metabolism is essential for the brain: it not only provides the required energy for cellular function and communication but also participates in balancing the levels of oxidative stress in neurons. Defects in glucose metabolism have been described in neurodegenerative disease; however, it remains unclear how this fundamental process contributes to neuronal cell death in these disorders. Here, we investigated the molecular mechanisms driving the selective neurodegeneration in an ataxic mouse model lacking oxidation resistance 1 (Oxr1) and discovered an unexpected function for this protein as a regulator of the glycolytic enzyme, glucose-6-phosphate isomerase (GPI/Gpi1). Initially, we present a dysregulation of metabolites of glucose metabolism at the pre-symptomatic stage in the Oxr1 knockout cerebellum. We then demonstrate that Oxr1 and Gpi1 physically and functionally interact and that the level of Gpi1 oligomerisation is disrupted when Oxr1 is deleted in vivo. Furthermore, we show that Oxr1 modulates the additional and less well-understood roles of Gpi1 as a cytokine and neuroprotective factor. Overall, our data identify a new molecular function for Oxr1, establishing this protein as important player in neuronal survival, regulating both oxidative stress and glucose metabolism in the brain.
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Affiliation(s)
- Mattéa J Finelli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
| | - Teresa Paramo
- Department of Biochemistry, University of Oxford, Parks Road, Oxford, OX1 3QU, UK
| | - Elisabete Pires
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Brent J Ryan
- Oxford Parkinson's Disease Centre, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK
| | - Richard Wade-Martins
- Department of Biochemistry, University of Oxford, Parks Road, Oxford, OX1 3QU, UK
| | - Philip C Biggin
- Department of Biochemistry, University of Oxford, Parks Road, Oxford, OX1 3QU, UK
| | - James McCullagh
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK. .,MRC Harwell Institute, Harwell Campus, South Parks Road, Oxford, Oxfordshire, OX11 0RD, UK.
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31
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Barros LF, Bolaños JP, Bonvento G, Bouzier-Sore AK, Brown A, Hirrlinger J, Kasparov S, Kirchhoff F, Murphy AN, Pellerin L, Robinson MB, Weber B. Current technical approaches to brain energy metabolism. Glia 2018; 66:1138-1159. [PMID: 29110344 PMCID: PMC5903992 DOI: 10.1002/glia.23248] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/14/2017] [Accepted: 10/04/2017] [Indexed: 12/19/2022]
Abstract
Neuroscience is a technology-driven discipline and brain energy metabolism is no exception. Once satisfied with mapping metabolic pathways at organ level, we are now looking to learn what it is exactly that metabolic enzymes and transporters do and when, where do they reside, how are they regulated, and how do they relate to the specific functions of neurons, glial cells, and their subcellular domains and organelles, in different areas of the brain. Moreover, we aim to quantify the fluxes of metabolites within and between cells. Energy metabolism is not just a necessity for proper cell function and viability but plays specific roles in higher brain functions such as memory processing and behavior, whose mechanisms need to be understood at all hierarchical levels, from isolated proteins to whole subjects, in both health and disease. To this aim, the field takes advantage of diverse disciplines including anatomy, histology, physiology, biochemistry, bioenergetics, cellular biology, molecular biology, developmental biology, neurology, and mathematical modeling. This article presents a well-referenced synopsis of the technical side of brain energy metabolism research. Detail and jargon are avoided whenever possible and emphasis is given to comparative strengths, limitations, and weaknesses, information that is often not available in regular articles.
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Affiliation(s)
- L Felipe Barros
- Centro de Estudios Científicos (CECs), Valdivia, 5110466, Chile
| | - Juan P Bolaños
- Instituto de Biologia Funcional y Genomica-CSIC, Universidad de Salamanca, CIBERFES, Salamanca, 37007, Spain
| | - Gilles Bonvento
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Anne-Karine Bouzier-Sore
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS-Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Angus Brown
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Johannes Hirrlinger
- Carl Ludwig Institute of Physiology, University of Leipzig, Liebigstr. 27, D-04103, Leipzig, Germany
- Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, Göttingen, D-37075, Germany
| | - Sergey Kasparov
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, BS8 1TD, United Kingdom
- Baltic Federal University, Kalinigrad, Russian Federation
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine, University of Saarland, Building 48, Homburg, 66421, Germany
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093
| | - Luc Pellerin
- Département de Physiologie, 7 rue du Bugnon, Lausanne, CH1005, Switzerland
| | - Michael B Robinson
- Department of Pediatrics, and Department of Systems Pharmacology and Translational Therapeutics, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, Zurich, Switzerland
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32
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Vandoorne T, De Bock K, Van Den Bosch L. Energy metabolism in ALS: an underappreciated opportunity? Acta Neuropathol 2018; 135:489-509. [PMID: 29549424 PMCID: PMC5978930 DOI: 10.1007/s00401-018-1835-x] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/08/2018] [Accepted: 03/08/2018] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive and fatal neurodegenerative disorder that primarily affects motor neurons. Despite our increased understanding of the genetic factors contributing to ALS, no effective treatment is available. A growing body of evidence shows disturbances in energy metabolism in ALS. Moreover, the remarkable vulnerability of motor neurons to ATP depletion has become increasingly clear. Here, we review metabolic alterations present in ALS patients and models, discuss the selective vulnerability of motor neurons to energetic stress, and provide an overview of tested and emerging metabolic approaches to treat ALS. We believe that a further understanding of the metabolic biology of ALS can lead to the identification of novel therapeutic targets.
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Affiliation(s)
- Tijs Vandoorne
- Department of Neurosciences, Experimental Neurology, KU Leuven-University of Leuven, Campus Gasthuisberg O&N 4, Herestraat 49, PB 602, 3000, Leuven, Belgium
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, 3000, Leuven, Belgium
| | - Katrien De Bock
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology, KU Leuven-University of Leuven, Campus Gasthuisberg O&N 4, Herestraat 49, PB 602, 3000, Leuven, Belgium.
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, 3000, Leuven, Belgium.
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33
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Vallée A, Lecarpentier Y, Guillevin R, Vallée JN. Thermodynamics in Neurodegenerative Diseases: Interplay Between Canonical WNT/Beta-Catenin Pathway-PPAR Gamma, Energy Metabolism and Circadian Rhythms. Neuromolecular Med 2018; 20:174-204. [PMID: 29572723 DOI: 10.1007/s12017-018-8486-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 03/20/2018] [Indexed: 02/06/2023]
Abstract
Entropy production rate is increased by several metabolic and thermodynamics abnormalities in neurodegenerative diseases (NDs). Irreversible processes are quantified by changes in the entropy production rate. This review is focused on the opposing interactions observed in NDs between the canonical WNT/beta-catenin pathway and PPAR gamma and their metabolic and thermodynamic implications. In amyotrophic lateral sclerosis and Huntington's disease, WNT/beta-catenin pathway is upregulated, whereas PPAR gamma is downregulated. In Alzheimer's disease and Parkinson's disease, WNT/beta-catenin pathway is downregulated while PPAR gamma is upregulated. The dysregulation of the canonical WNT/beta-catenin pathway is responsible for the modification of thermodynamics behaviors of metabolic enzymes. Upregulation of WNT/beta-catenin pathway leads to aerobic glycolysis, named Warburg effect, through activated enzymes, such as glucose transporter (Glut), pyruvate kinase M2 (PKM2), pyruvate dehydrogenase kinase 1(PDK1), monocarboxylate lactate transporter 1 (MCT-1), lactic dehydrogenase kinase-A (LDH-A) and inactivation of pyruvate dehydrogenase complex (PDH). Downregulation of WNT/beta-catenin pathway leads to oxidative stress and cell death through inactivation of Glut, PKM2, PDK1, MCT-1, LDH-A but activation of PDH. In addition, in NDs, PPAR gamma is dysregulated, whereas it contributes to the regulation of several key circadian genes. NDs show many dysregulation in the mediation of circadian clock genes and so of circadian rhythms. Thermodynamics rhythms operate far-from-equilibrium and partly regulate interactions between WNT/beta-catenin pathway and PPAR gamma. In NDs, metabolism, thermodynamics and circadian rhythms are tightly interrelated.
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Affiliation(s)
- Alexandre Vallée
- DRCI, Hôpital Foch, Suresnes, France.
- LMA (Laboratoire de Mathématiques et Applications) CNRS 7348, University of Poitiers, 11 Boulevard Marie et Pierre Curie, Poitiers, France.
| | - Yves Lecarpentier
- Centre de Recherche Clinique, Grand Hôpital de l'Est Francilien, Meaux, France
| | - Rémy Guillevin
- DACTIM, UMR CNRS 7348, Université de Poitiers et CHU de Poitiers, Poitiers, France
| | - Jean-Noël Vallée
- DRCI, Hôpital Foch, Suresnes, France
- CHU Amiens Picardie, Université Picardie Jules Verne (UPJV), Amiens, France
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34
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Abstract
Lactate in the brain has long been associated with ischaemia; however, more recent evidence shows that it can be found there under physiological conditions. In the brain, lactate is formed predominantly in astrocytes from glucose or glycogen in response to neuronal activity signals. Thus, neurons and astrocytes show tight metabolic coupling. Lactate is transferred from astrocytes to neurons to match the neuronal energetic needs, and to provide signals that modulate neuronal functions, including excitability, plasticity and memory consolidation. In addition, lactate affects several homeostatic functions. Overall, lactate ensures adequate energy supply, modulates neuronal excitability levels and regulates adaptive functions in order to set the 'homeostatic tone' of the nervous system.
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35
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Barros LF, Weber B. CrossTalk proposal: an important astrocyte-to-neuron lactate shuttle couples neuronal activity to glucose utilisation in the brain. J Physiol 2018; 596:347-350. [PMID: 29292516 DOI: 10.1113/jp274944] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- L F Barros
- Centro de Estudios Científicos, Valdivia, 5110466, Chile
| | - B Weber
- Institute of Pharmacology and Toxicology, University of Zurich, and Neuroscience Center Zurich, Zurich, CH-8057, Switzerland
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36
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Lanthanum chloride reduces lactate production in primary culture rat cortical astrocytes and suppresses primary co-culture rat cortical astrocyte-neuron lactate transport. Arch Toxicol 2017; 92:1407-1419. [DOI: 10.1007/s00204-017-2148-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/14/2017] [Indexed: 12/18/2022]
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37
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Kong L, Zhao Y, Zhou WJ, Yu H, Teng SW, Guo Q, Chen Z, Wang Y. Direct Neuronal Glucose Uptake Is Required for Contextual Fear Acquisition in the Dorsal Hippocampus. Front Mol Neurosci 2017; 10:388. [PMID: 29209168 PMCID: PMC5702440 DOI: 10.3389/fnmol.2017.00388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/07/2017] [Indexed: 11/13/2022] Open
Abstract
The metabolism of glucose is a nearly exclusive source of energy for maintaining neuronal survival, synaptic transmission and information processing in the brain. Two glucose metabolism pathways have been reported, direct neuronal glucose uptake and the astrocyte-neuron lactate shuttle (ANLS), which can be involved in these functions simultaneously or separately. Although ANLS in the dorsal hippocampus (DH) has been proved to be required for memory consolidation, the specific metabolic pathway involved during memory acquisition remains unclear. The DH and amygdala are two key brain regions for acquisition of contextual fear conditioning (CFC). In 2-NBDG experiments, we observed that 2-NBDG-positive neurons were significantly increased during the acquisition of CFC in the DH. However, in the amygdala and cerebellum, 2-NBDG-positive neurons were not changed during CFC training. Strikingly, microinjection of a glucose transporter (GLUT) inhibitor into the DH decreased freezing values during CFC training and 1 h later, while injection of a monocarboxylate transporter (MCT) inhibitor into the amygdala also reduced freezing values. Therefore, we demonstrated that direct neuronal glucose uptake was the primary means of energy supply in the DH, while ANLS might supply energy in the amygdala during acquisition. Furthermore, knockdown of GLUT3 by a lentivirus in the DH impaired the acquisition of CFC. Taken together, the results indicated that there were two different glucose metabolism pathways in the DH and amygdala during acquisition of contextual fear memory and that direct neuronal glucose uptake in the DH may be regulated by GLUT3.
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Affiliation(s)
- Liang Kong
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China.,Department of Clinical Laboratory, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yan Zhao
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Wen-Juan Zhou
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Hui Yu
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Shuai-Wen Teng
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Qi Guo
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Zheyu Chen
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
| | - Yue Wang
- Department of Cell and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Science, Shandong University, Jinan, China
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38
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Reprogramming energetic metabolism in Alzheimer's disease. Life Sci 2017; 193:141-152. [PMID: 29079469 DOI: 10.1016/j.lfs.2017.10.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/23/2017] [Indexed: 12/20/2022]
Abstract
Entropy rate is increased by several metabolic and thermodynamics abnormalities in neurodegenerative diseases (NDs). Changes in Gibbs energy, heat production, ionic conductance or intracellular acidity are irreversibles processes which driven modifications of the entropy rate. The present review focusses on the thermodynamic implications in the reprogramming of cellular energy metabolism enabling in Alzheimer's disease (AD) through the opposite interplay of the molecular signaling pathways WNT/β-catenin and PPARγ. In AD, WNT/β-catenin pathway is downregulated while PPARγ is upregulated. Thermodynamics behaviors of metabolic enzymes are modified by dysregulation of the canonical WNT/β-catenin pathway. Downregulation of WNT/β-catenin pathway leads to oxidative stress and cell death through inactivation of glycolytic enzymes such as Glut, PKM2, PDK1, MCT-1, LDH-A but activation of PDH. In addition, in NDs, PPARγ is dysregulated whereas it contributes to the regulation of several key circadian genes. AD is considered as a dissipative structure that exchanges energy or matter with its environment far from the thermodynamic equilibrium. Far-from-equilibrium thermodynamics are notions driven by circadian rhythms. Circadian rhythms directly participate in regulating the molecular pathways WNT/β-catenin and PPARγ involved in the reprogramming of cellular energy metabolism enabling AD processes.
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39
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Lourenço CF, Ledo A, Barbosa RM, Laranjinha J. Neurovascular-neuroenergetic coupling axis in the brain: master regulation by nitric oxide and consequences in aging and neurodegeneration. Free Radic Biol Med 2017; 108:668-682. [PMID: 28435052 DOI: 10.1016/j.freeradbiomed.2017.04.026] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 02/21/2017] [Accepted: 04/18/2017] [Indexed: 02/08/2023]
Abstract
The strict energetic demands of the brain require that nutrient supply and usage be fine-tuned in accordance with the specific temporal and spatial patterns of ever-changing levels of neuronal activity. This is achieved by adjusting local cerebral blood flow (CBF) as a function of activity level - neurovascular coupling - and by changing how energy substrates are metabolized and shuttled amongst astrocytes and neurons - neuroenergetic coupling. Both activity-dependent increase of CBF and O2 and glucose utilization by active neural cells are inextricably linked, establishing a functional metabolic axis in the brain, the neurovascular-neuroenergetic coupling axis. This axis incorporates and links previously independent processes that need to be coordinated in the normal brain. We here review evidence supporting the role of neuronal-derived nitric oxide (•NO) as the master regulator of this axis. Nitric oxide is produced in tight association with glutamatergic activation and, diffusing several cell diameters, may interact with different molecular targets within each cell type. Hemeproteins such as soluble guanylate cyclase, cytochrome c oxidase and hemoglobin, with which •NO reacts at relatively fast rates, are but a few of the key in determinants of the regulatory role of •NO in the neurovascular-neuroenergetic coupling axis. Accordingly, critical literature supporting this concept is discussed. Moreover, in view of the controversy regarding the regulation of catabolism of different neural cells, we further discuss key aspects of the pathways through which •NO specifically up-regulates glycolysis in astrocytes, supporting lactate shuttling to neurons for oxidative breakdown. From a biomedical viewpoint, derailment of neurovascular-neuroenergetic axis is precociously linked to aberrant brain aging, cognitive impairment and neurodegeneration. Thus, we summarize current knowledge of how both neurovascular and neuroenergetic coupling are compromised in aging, traumatic brain injury, epilepsy and age-associated neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease, suggesting that a shift in cellular redox balance may contribute to divert •NO bioactivity from regulation to dysfunction.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Ana Ledo
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Rui M Barbosa
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.
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40
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Oheim M, Schmidt E, Hirrlinger J. Local energy on demand: Are 'spontaneous' astrocytic Ca 2+-microdomains the regulatory unit for astrocyte-neuron metabolic cooperation? Brain Res Bull 2017; 136:54-64. [PMID: 28450076 DOI: 10.1016/j.brainresbull.2017.04.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/18/2017] [Accepted: 04/21/2017] [Indexed: 12/21/2022]
Abstract
Astrocytes are a neural cell type critically involved in maintaining brain energy homeostasis as well as signaling. Like neurons, astrocytes are a heterogeneous cell population. Cortical astrocytes show a complex morphology with a highly branched aborization and numerous fine processes ensheathing the synapses of neighboring neurons, and typically extend one process connecting to blood vessels. Recent studies employing genetically encoded fluorescent calcium (Ca2+) indicators have described 'spontaneous' localized Ca2+-transients in the astrocyte periphery that occur asynchronously, independently of signals in other parts of the cells, and that do not involve somatic Ca2+ transients; however, neither it is known whether these Ca2+-microdomains occur at or near neuronal synapses nor have their molecular basis nor downstream effector(s) been identified. In addition to Ca2+ microdomains, sodium (Na+) transients occur in astrocyte subdomains, too, most likely as a consequence of Na+ co-transport with the neurotransmitter glutamate, which also regulates mitochondrial movements locally - as do cytoplasmic Ca2+ levels. In this review, we cover various aspects of these local signaling events and discuss how structural and biophysical properties of astrocytes might foster such compartmentation. Astrocytes metabolically interact with neurons by providing energy substrates to active neurons. As a single astrocyte branch covers hundreds to thousands of synapses, it is tempting to speculate that these metabolic interactions could occur localized to specific subdomains of astrocytes, perhaps even at the level of small groups of synapses. We discuss how astrocytic metabolism might be regulated at this scale and which signals might contribute to its regulation. We speculate that the astrocytic structures that light up transiently as Ca2+-microdomains might be the functional units of astrocytes linking signaling and metabolic processes to adapt astrocytic function to local energy demands. The understanding of these local regulatory and metabolic interactions will be fundamental to fully appreciate the complexity of brain energy homeostasis as well as its failure in disease and may shed new light on the controversy about neuron-glia bi-directional signaling at the tripartite synapse.
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Affiliation(s)
- Martin Oheim
- CNRS UMR 8118, Brain Physiology Laboratory, F-75006 Paris, France; Fédération de Recherche en Neurosciences FR3636, Faculté de Sciences Fondamentales et Biomédicales, Université Paris Descartes, PRES Université Sorbonne Paris Cité (USPC), F-75006 Paris, France.
| | - Elke Schmidt
- CNRS UMR 8118, Brain Physiology Laboratory, F-75006 Paris, France; Fédération de Recherche en Neurosciences FR3636, Faculté de Sciences Fondamentales et Biomédicales, Université Paris Descartes, PRES Université Sorbonne Paris Cité (USPC), F-75006 Paris, France
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, D-04103 Leipzig, Germany; Dept. of Neurogenetics, Max-Planck-Institute for Experimental Medicine, D-37075 Göttingen, Germany.
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41
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Zimmer P, Binnebößel S, Bloch W, Hübner ST, Schenk A, Predel HG, Wright P, Stritt C, Oberste M. Exhaustive Exercise Alters Thinking Times in a Tower of London Task in a Time-Dependent Manner. Front Physiol 2017; 7:694. [PMID: 28127289 PMCID: PMC5226945 DOI: 10.3389/fphys.2016.00694] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 12/29/2016] [Indexed: 11/13/2022] Open
Abstract
Purpose: In contrast to other aspects of executive functions, acute exercise-induced alterations in planning are poorly investigated. While only few studies report improved planning performances after exercise, even less is known about their time course after exhaustive exercise. Methods: One hundred and nineteen healthy adults performed the Tower of London (ToL) task at baseline, followed by a graded exercise test (GXT). Participants were subsequently randomized into one of four groups (immediately, 30, 60, and 90 min after the GXT) to repeat the ToL. Main outcomes of the ToL were planning (number of tasks completed in the minimum number of moves), solutions (correct responses independent of the given number of moves) as well as thinking times (time between presentation of each problem and first action) for tasks with varying difficulty (four-, five,- and six-move problems). Blood lactate levels were analyzed as a potential mediator. Results: No effect of exercise on planning could be detected. In contrast to complex problem conditions, median thinking times deteriorated significantly in the immediately after GXT tested group in less challenging problem conditions (four-move problems: p = 0.001, F = 5.933, df = 3; five-move problems: p = 0.005, F = 4.548, df = 3). Decreased lactate elimination rates were associated with impaired median thinking times across all groups ΔMTT4-6 (p = 0.001, r = −0.309), ΔMTT4 (p < 0.001, r = −0.367), and ΔMTT5 (p = 0.001, r = −0.290). Conclusion: These results suggest that planning does not improve within 90 min after exhaustive exercise. In line with previous research, revealing a negative impact of exhaustive exercise on memory and attention, our study extends this knowledge of exercise-induced alterations in cognitive functioning as thinking times as subcomponents of planning are negatively affected immediately after exercise. This is further associated with peripheral lactate levels.
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Affiliation(s)
- Philipp Zimmer
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University CologneCologne, Germany; National Center for Tumor Diseases (NCT) and German Cancer Research CenterHeidelberg, Germany
| | - Stephan Binnebößel
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Wilhelm Bloch
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Sven T Hübner
- Institute of Cardiovascular Research and Sports Medicine, Department for Preventive and Rehabilitative Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Alexander Schenk
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Hans-Georg Predel
- Institute of Cardiovascular Research and Sports Medicine, Department for Preventive and Rehabilitative Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Peter Wright
- Chair of Sports Medicine, Chemnitz University of Technology Chemnitz, Germany
| | - Christian Stritt
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne Cologne, Germany
| | - Max Oberste
- Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne Cologne, Germany
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Gutiérrez Aguilar GF, Alquisiras-Burgos I, Espinoza-Rojo M, Aguilera P. Glial Excitatory Amino Acid Transporters and Glucose Incorporation. ADVANCES IN NEUROBIOLOGY 2017; 16:269-282. [PMID: 28828615 DOI: 10.1007/978-3-319-55769-4_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Excitatory amino acid transporters (EAATs) expressed in astrocytes remove the glutamate released by neurons in and around the synaptic cleft. In this manner, astrocytes preserve the signaling functions mediated by glutamate on synapses and prevent excitotoxicity. Additionally, EAAT activation stimulates glucose utilization in astrocytes, linking neuronal activity with astrocyte metabolism. In this chapter, we briefly review the characteristics of the EAATs and the glucose transporters (GLUTs) expressed in the brain. Thereafter, we focus on the effect of EAATs activation and its association with glucose utilization in astrocytes, specifically addressing the role played by Na+ and Ca2+ ions. Next, we analyze evidence that proposes mechanisms by which the activity of GLUTs could be modulated after EAAT activation (e.g., kinases altering GLUTs traffic to cell membrane). Finally, we analyzed the current knowledge on EAAT function during energy deficiency as a possible inducer of GLUT expression to prevent neuronal damage.
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Affiliation(s)
- Germán Fernando Gutiérrez Aguilar
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, Col. La Fama, Tlalpan, Ciudad de México, 14269, México
| | - Ivan Alquisiras-Burgos
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, Col. La Fama, Tlalpan, Ciudad de México, 14269, México
| | - Mónica Espinoza-Rojo
- Laboratorio de Biología Molecular y Genómica, Universidad Autónoma de Guerrero, Chilpancingo, Guerrero, 39087, México
| | - Penélope Aguilera
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Insurgentes Sur #3877, Col. La Fama, Tlalpan, Ciudad de México, 14269, México.
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Hladky SB, Barrand MA. Fluid and ion transfer across the blood-brain and blood-cerebrospinal fluid barriers; a comparative account of mechanisms and roles. Fluids Barriers CNS 2016; 13:19. [PMID: 27799072 PMCID: PMC5508927 DOI: 10.1186/s12987-016-0040-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/01/2016] [Indexed: 12/24/2022] Open
Abstract
The two major interfaces separating brain and blood have different primary roles. The choroid plexuses secrete cerebrospinal fluid into the ventricles, accounting for most net fluid entry to the brain. Aquaporin, AQP1, allows water transfer across the apical surface of the choroid epithelium; another protein, perhaps GLUT1, is important on the basolateral surface. Fluid secretion is driven by apical Na+-pumps. K+ secretion occurs via net paracellular influx through relatively leaky tight junctions partially offset by transcellular efflux. The blood-brain barrier lining brain microvasculature, allows passage of O2, CO2, and glucose as required for brain cell metabolism. Because of high resistance tight junctions between microvascular endothelial cells transport of most polar solutes is greatly restricted. Because solute permeability is low, hydrostatic pressure differences cannot account for net fluid movement; however, water permeability is sufficient for fluid secretion with water following net solute transport. The endothelial cells have ion transporters that, if appropriately arranged, could support fluid secretion. Evidence favours a rate smaller than, but not much smaller than, that of the choroid plexuses. At the blood-brain barrier Na+ tracer influx into the brain substantially exceeds any possible net flux. The tracer flux may occur primarily by a paracellular route. The blood-brain barrier is the most important interface for maintaining interstitial fluid (ISF) K+ concentration within tight limits. This is most likely because Na+-pumps vary the rate at which K+ is transported out of ISF in response to small changes in K+ concentration. There is also evidence for functional regulation of K+ transporters with chronic changes in plasma concentration. The blood-brain barrier is also important in regulating HCO3- and pH in ISF: the principles of this regulation are reviewed. Whether the rate of blood-brain barrier HCO3- transport is slow or fast is discussed critically: a slow transport rate comparable to those of other ions is favoured. In metabolic acidosis and alkalosis variations in HCO3- concentration and pH are much smaller in ISF than in plasma whereas in respiratory acidosis variations in pHISF and pHplasma are similar. The key similarities and differences of the two interfaces are summarized.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD UK
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Fonseca R, Carvalho RA, Lemos C, Sequeira AC, Pita IR, Carvalho F, Silva CD, Prediger RDS, Jarak I, Cunha RA, Fontes Ribeiro CA, Köfalvi A, Pereira FC. Methamphetamine Induces Anhedonic-Like Behavior and Impairs Frontal Cortical Energetics in Mice. CNS Neurosci Ther 2016; 23:119-126. [PMID: 27762079 DOI: 10.1111/cns.12649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 01/18/2023] Open
Abstract
INTRODUCTION We recently showed that a single high dose of methamphetamine (METH) induces a persistent frontal cortical monoamine depletion that is accompanied by helpless-like behavior in mice. However, brain metabolic alterations underlying both neurochemical and mood alterations remain unknown. AIMS Herein, we aimed at characterizing frontal cortical metabolic alterations associated with early negative mood behavior triggered by METH. Adult C57BL/6 mice were injected with METH (30 mg/kg, i.p.), and their frontal cortical metabolic status was characterized after probing their mood and anxiety-related phenotypes 3 days postinjection. RESULTS Methamphetamine induced depressive-like behavior, as indicated by the decreased grooming time in the splash test and by a transient decrease in sucrose preference. At this time, METH did not alter anxiety-like behavior or motor functions. Depolarization-induced glucose uptake was reduced in frontocortical slices from METH-treated mice compared to controls. Consistently, astrocytic glucose transporter (GluT1) density was lower in the METH group. A proton high rotation magic angle spinning (HRMAS) spectroscopic approach revealed that METH induced a significant decrease in N-acetyl aspartate (NAA) and glutamate levels, suggesting that METH decreased neuronal glutamatergic function in frontal cortex. CONCLUSIONS We report, for the first time, that a single METH injection triggers early self-care and hedonic deficits and impairs frontal cortical energetics in mice.
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Affiliation(s)
- Raquel Fonseca
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui A Carvalho
- CNC.IBILI, University of Coimbra, Coimbra, Portugal.,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Cristina Lemos
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ana C Sequeira
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Inês R Pita
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Fábio Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Carlos D Silva
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Rui D S Prediger
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, UFSC, Florianópolis, Brazil
| | - Ivana Jarak
- CNC.IBILI, University of Coimbra, Coimbra, Portugal.,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC.IBILI, University of Coimbra, Coimbra, Portugal.,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Carlos A Fontes Ribeiro
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
| | - Attila Köfalvi
- CNC.IBILI, University of Coimbra, Coimbra, Portugal.,CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Frederico C Pereira
- Laboratory of Pharmacology and Experimental Therapeutics/Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI, University of Coimbra, Coimbra, Portugal
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45
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Valdebenito R, Ruminot I, Garrido-Gerter P, Fernández-Moncada I, Forero-Quintero L, Alegría K, Becker HM, Deitmer JW, Barros LF. Targeting of astrocytic glucose metabolism by beta-hydroxybutyrate. J Cereb Blood Flow Metab 2016; 36:1813-1822. [PMID: 26661221 PMCID: PMC5076786 DOI: 10.1177/0271678x15613955] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 07/14/2015] [Indexed: 11/17/2022]
Abstract
The effectiveness of ketogenic diets and intermittent fasting against neurological disorders has brought interest to the effects of ketone bodies on brain cells. These compounds are known to modify the metabolism of neurons, but little is known about their effect on astrocytes, cells that control the supply of glucose to neurons and also modulate neuronal excitability through the glycolytic production of lactate. Here we have used genetically-encoded Förster Resonance Energy Transfer nanosensors for glucose, pyruvate and ATP to characterize astrocytic energy metabolism at cellular resolution. Our results show that the ketone body beta-hydroxybutyrate strongly inhibited astrocytic glucose consumption in mouse astrocytes in mixed cultures, in organotypic hippocampal slices and in acute hippocampal slices prepared from ketotic mice, while blunting the stimulation of glycolysis by physiological and pathophysiological stimuli. The inhibition of glycolysis was paralleled by an increased ability of astrocytic mitochondria to metabolize pyruvate. These results support the emerging notion that astrocytes contribute to the neuroprotective effect of ketone bodies.
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Affiliation(s)
| | - Iván Ruminot
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
| | - Pamela Garrido-Gerter
- Centro de Estudios Científicos, Valdivia, Chile Universidad Austral de Chile, Valdivia, Chile
| | | | | | | | - Holger M Becker
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
| | - Joachim W Deitmer
- General Zoology/University of Kaiserslautern, Kaiserslautern, Germany
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46
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DiNuzzo M, Giove F, Maraviglia B, Mangia S. Computational Flux Balance Analysis Predicts that Stimulation of Energy Metabolism in Astrocytes and their Metabolic Interactions with Neurons Depend on Uptake of K + Rather than Glutamate. Neurochem Res 2016; 42:202-216. [PMID: 27628293 PMCID: PMC5283516 DOI: 10.1007/s11064-016-2048-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 12/04/2022]
Abstract
Brain activity involves essential functional and metabolic interactions between neurons and astrocytes. The importance of astrocytic functions to neuronal signaling is supported by many experiments reporting high rates of energy consumption and oxidative metabolism in these glial cells. In the brain, almost all energy is consumed by the Na+/K+ ATPase, which hydrolyzes 1 ATP to move 3 Na+ outside and 2 K+ inside the cells. Astrocytes are commonly thought to be primarily involved in transmitter glutamate cycling, a mechanism that however only accounts for few % of brain energy utilization. In order to examine the participation of astrocytic energy metabolism in brain ion homeostasis, here we attempted to devise a simple stoichiometric relation linking glutamatergic neurotransmission to Na+ and K+ ionic currents. To this end, we took into account ion pumps and voltage/ligand-gated channels using the stoichiometry derived from available energy budget for neocortical signaling and incorporated this stoichiometric relation into a computational metabolic model of neuron-astrocyte interactions. We aimed at reproducing the experimental observations about rates of metabolic pathways obtained by 13C-NMR spectroscopy in rodent brain. When simulated data matched experiments as well as biophysical calculations, the stoichiometry for voltage/ligand-gated Na+ and K+ fluxes generated by neuronal activity was close to a 1:1 relationship, and specifically 63/58 Na+/K+ ions per glutamate released. We found that astrocytes are stimulated by the extracellular K+ exiting neurons in excess of the 3/2 Na+/K+ ratio underlying Na+/K+ ATPase-catalyzed reaction. Analysis of correlations between neuronal and astrocytic processes indicated that astrocytic K+ uptake, but not astrocytic Na+-coupled glutamate uptake, is instrumental for the establishment of neuron-astrocytic metabolic partnership. Our results emphasize the importance of K+ in stimulating the activation of astrocytes, which is relevant to the understanding of brain activity and energy metabolism at the cellular level.
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Affiliation(s)
- Mauro DiNuzzo
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 24.2.40, 2200, Copenhagen N, Denmark.
| | - Federico Giove
- Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy.,Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Bruno Maraviglia
- Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi", Rome, Italy.,Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Silvia Mangia
- Center for Magnetic Resonance Research, Department of Radiology, Univeristy of Minnesota, Minneapolis, MN, USA
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Theparambil SM, Weber T, Schmälzle J, Ruminot I, Deitmer JW. Proton Fall or Bicarbonate Rise: GLYCOLYTIC RATE IN MOUSE ASTROCYTES IS PAVED BY INTRACELLULAR ALKALINIZATION. J Biol Chem 2016; 291:19108-17. [PMID: 27422823 PMCID: PMC5009280 DOI: 10.1074/jbc.m116.730143] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Indexed: 01/08/2023] Open
Abstract
Glycolysis is the primary step for major energy production in the cell. There is strong evidence suggesting that glucose consumption and rate of glycolysis are highly modulated by cytosolic pH/[H(+)], but those can also be stimulated by an increase in the intracellular [HCO3 (-)]. Because proton and bicarbonate shift concomitantly, it remained unclear whether enhanced glucose consumption and glycolytic rate were mediated by the changes in intracellular [H(+)] or [HCO3 (-)]. We have asked whether glucose metabolism is enhanced by either a fall in intracellular [H(+)] or a rise in intracellular [HCO3 (-)], or by both, in mammalian astrocytes. We have recorded intracellular glucose in mouse astrocytes using a FRET-based nanosensor, while imposing different intracellular [H(+)] and [CO2]/[HCO3 (-)]. Glucose consumption and glycolytic rate were augmented by a fall in intracellular [H(+)], irrespective of a concomitant rise or fall in intracellular [HCO3 (-)]. Transport of HCO3 (-) into and out of astrocytes by the electrogenic sodium bicarbonate cotransporter (NBCe1) played a crucial role in causing changes in intracellular pH and [HCO3 (-)], but was not obligatory for the pH-dependent changes in glucose metabolism. Our results clearly show that it is the cytosolic pH that modulates glucose metabolism in cortical astrocytes, and possibly also in other cell types.
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Affiliation(s)
- Shefeeq M Theparambil
- From the Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserlautern, P. B. 3049, D-67653 Kaiserslautern, Germany and
| | - Tobias Weber
- From the Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserlautern, P. B. 3049, D-67653 Kaiserslautern, Germany and
| | - Jana Schmälzle
- From the Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserlautern, P. B. 3049, D-67653 Kaiserslautern, Germany and
| | - Ivàn Ruminot
- From the Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserlautern, P. B. 3049, D-67653 Kaiserslautern, Germany and the Centro de Estudios Científicos (CECs), Valdivia 5110466, Chile
| | - Joachim W Deitmer
- From the Abteilung für Allgemeine Zoologie, FB Biologie, University of Kaiserlautern, P. B. 3049, D-67653 Kaiserslautern, Germany and
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48
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Hernandez-Garzón E, Fernandez AM, Perez-Alvarez A, Genis L, Bascuñana P, Fernandez de la Rosa R, Delgado M, Angel Pozo M, Moreno E, McCormick PJ, Santi A, Trueba-Saiz A, Garcia-Caceres C, Tschöp MH, Araque A, Martin ED, Torres Aleman I. The insulin-like growth factor I receptor regulates glucose transport by astrocytes. Glia 2016; 64:1962-71. [PMID: 27462832 DOI: 10.1002/glia.23035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 12/20/2022]
Abstract
Previous findings indicate that reducing brain insulin-like growth factor I receptor (IGF-IR) activity promotes ample neuroprotection. We now examined a possible action of IGF-IR on brain glucose transport to explain its wide protective activity, as energy availability is crucial for healthy tissue function. Using (18) FGlucose PET we found that shRNA interference of IGF-IR in mouse somatosensory cortex significantly increased glucose uptake upon sensory stimulation. In vivo microscopy using astrocyte specific staining showed that after IGF-IR shRNA injection in somatosensory cortex, astrocytes displayed greater increases in glucose uptake as compared to astrocytes in the scramble-injected side. Further, mice with the IGF-IR knock down in astrocytes showed increased glucose uptake in somatosensory cortex upon sensory stimulation. Analysis of underlying mechanisms indicated that IGF-IR interacts with glucose transporter 1 (GLUT1), the main facilitative glucose transporter in astrocytes, through a mechanism involving interactions with the scaffolding protein GIPC and the multicargo transporter LRP1 to retain GLUT1 inside the cell. These findings identify IGF-IR as a key modulator of brain glucose metabolism through its inhibitory action on astrocytic GLUT1 activity. GLIA 2016;64:1962-1971.
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Affiliation(s)
| | | | - Alberto Perez-Alvarez
- Cajal Institute, CSIC, Madrid, Spain.,Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Laura Genis
- Cajal Institute, CSIC, Madrid, Spain.,Ciberned, Spain
| | - Pablo Bascuñana
- Pluridisciplinary Institute, Complutense University, Madrid, Spain
| | | | - Mercedes Delgado
- Pluridisciplinary Institute, Complutense University, Madrid, Spain
| | | | - Estefania Moreno
- Ciberned, Spain.,Dept Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
| | - Peter J McCormick
- Ciberned, Spain.,Dept Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain.,School of Pharmacy, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Andrea Santi
- Cajal Institute, CSIC, Madrid, Spain.,Ciberned, Spain
| | | | | | | | | | - Eduardo D Martin
- Science and Technology Park, Institute for Research in Neurological Disabilities, University of Castilla-La Mancha, Albacete, Spain
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49
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Mendez-Flores OG, Hernández-Kelly LC, Suárez-Pozos E, Najimi M, Ortega A. Coupling of glutamate and glucose uptake in cultured Bergmann glial cells. Neurochem Int 2016; 98:72-81. [PMID: 27184733 DOI: 10.1016/j.neuint.2016.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 04/25/2016] [Accepted: 05/02/2016] [Indexed: 11/17/2022]
Abstract
Glutamate, the main excitatory neurotransmitter in the vertebrate brain, exerts its actions through specific membrane receptors present in neurons and glial cells. Over-stimulation of glutamate receptors results in neuronal death, phenomena known as excitotoxicity. A family of sodium-dependent, glutamate uptake transporters mainly expressed in glial cells, removes the amino acid from the synaptic cleft preventing neuronal death. The sustained sodium influx associated to glutamate removal in glial cells, activates the sodium/potassium ATPase restoring the ionic balance, additionally, glutamate entrance activates glutamine synthetase, both events are energy demanding, therefore glia cells increase their ATP expenditure favouring glucose uptake, and triggering several signal transduction pathways linked to proper neuronal glutamate availability, via the glutamate/glutamine shuttle. To further characterize these complex transporters interactions, we used the well-established model system of cultured chick cerebellum Bergmann glia cells. A time and dose-dependent increase in the activity, plasma membrane localization and protein levels of glucose transporters was detected upon d-aspartate exposure. Interestingly, this increase is the result of a protein kinase C-dependent signaling cascade. Furthermore, a glutamate-dependent glucose and glutamate transporters co-immunoprecipitation was detected. These results favour the notion that glial cells are involved in glutamatergic neuronal physiology.
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Affiliation(s)
- Orquidia G Mendez-Flores
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Luisa C Hernández-Kelly
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Edna Suárez-Pozos
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico
| | - Mustapha Najimi
- Laboratory of Pediatric Hepatology and Cell Therapy, Institut de Recherche Expérimentale et Clinique, Cliniques Universitaires St Luc, Université catholique de Louvain, 1200 Brussels, Belgium
| | - Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados (Cinvestav) del Instituto Politécnico Nacional (IPN), México D.F. 07000, Mexico.
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50
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Lee CY, Dallérac G, Ezan P, Anderova M, Rouach N. Glucose Tightly Controls Morphological and Functional Properties of Astrocytes. Front Aging Neurosci 2016; 8:82. [PMID: 27148048 PMCID: PMC4834307 DOI: 10.3389/fnagi.2016.00082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/01/2016] [Indexed: 01/14/2023] Open
Abstract
The main energy source powering the brain is glucose. Strong energy needs of our nervous system are fulfilled by conveying this essential metabolite through blood via an extensive vascular network. Glucose then reaches brain tissues by cell uptake, diffusion and metabolization, processes primarily undertaken by astrocytes. Deprivation of glucose can however occur in various circumstances. In particular, ageing is associated with cognitive disturbances that are partly attributable to metabolic deficiency leading to brain glycopenia. Despite the crucial role of glucose and its metabolites in sustaining neuronal activity, little is known about its moment-to-moment contribution to astroglial physiology. We thus here investigated the early structural and functional alterations induced in astrocytes by a transient metabolic challenge consisting in glucose deprivation. Electrophysiological recordings of hippocampal astroglial cells of the stratum radiatumin situ revealed that shortage of glucose specifically increases astrocyte membrane capacitance, whilst it has no impact on other passive membrane properties. Consistent with this change, morphometric analysis unraveled a prompt increase in astrocyte volume upon glucose deprivation. Furthermore, characteristic functional properties of astrocytes are also affected by transient glucose deficiency. We indeed found that glucoprivation decreases their gap junction-mediated coupling, while it progressively and reversibly increases their intracellular calcium levels during the slow depression of synaptic transmission occurring simultaneously, as assessed by dual electrophysiological and calcium imaging recordings. Together, these data indicate that astrocytes rapidly respond to metabolic dysfunctions, and are therefore central to the neuroglial dialog at play in brain adaptation to glycopenia.
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Affiliation(s)
- Chun-Yao Lee
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University Paris, France
| | - Glenn Dallérac
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University Paris, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University Paris, France
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech RepublicPrague, Czech Republic; Department of Neuroscience, 2nd Faculty of Medicine, Charles UniversityPrague, Czech Republic
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, Centre National de la Recherche Scientifique UMR 7241, Institut National de la Santé et de la Recherche Médicale U1050, Labex Memolife, PSL Research University Paris, France
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