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Prasad SK, Acharjee A, Singh VV, Trigun SK, Acharjee P. Modulation of brain energy metabolism in hepatic encephalopathy: impact of glucose metabolic dysfunction. Metab Brain Dis 2024:10.1007/s11011-024-01407-7. [PMID: 39120853 DOI: 10.1007/s11011-024-01407-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024]
Abstract
Cerebral function is linked to a high level of metabolic activity and relies on glucose as its primary energy source. Glucose aids in the maintenance of physiological brain activities; as a result, a disruption in metabolism has a significant impact on brain function, launching a chain of events that leads to neuronal death. This metabolic insufficiency has been observed in a variety of brain diseases and neuroexcitotoxicity disorders, including hepatic encephalopathy. It is a significant neurological complication that develops in people with liver disease, ranging from asymptomatic abnormalities to coma. Hyperammonemia is the main neurotoxic villain in the development of hepatic encephalopathy and induces a wide range of complications in the brain. The neurotoxic effects of ammonia on brain function are thought to be mediated by impaired glucose metabolism. Accordingly, in this review, we provide an understanding of deranged brain energy metabolism, emphasizing the role of glucose metabolic dysfunction in the pathogenesis of hepatic encephalopathy. We also highlighted the differential metabolic profiles of brain cells and the status of metabolic cooperation between them. The major metabolic pathways that have been explored are glycolysis, glycogen metabolism, lactate metabolism, the pentose phosphate pathway, and the Krebs cycle. Furthermore, the lack of efficacy in current hepatic encephalopathy treatment methods highlights the need to investigate potential therapeutic targets for hepatic encephalopathy, with regulating deficient bioenergetics being a viable alternative in this case. This review also demonstrates the importance of the development of glucose metabolism-focused disease diagnostics and treatments, which are now being pursued for many ailments.
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Affiliation(s)
- Shambhu Kumar Prasad
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Arup Acharjee
- Department of Zoology, University of Allahabad, Prayagraj, 211002, India.
| | - Vishal Vikram Singh
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Surendra Kumar Trigun
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Papia Acharjee
- Biochemistry and Molecular Biology Unit, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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Llavero F, Zugaza JL. The importance of muscle glycogen phosphorylase in glial cells function. Biochem Soc Trans 2024; 52:1265-1274. [PMID: 38661212 DOI: 10.1042/bst20231058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024]
Abstract
The three isoforms of glycogen phosphorylase - PYGM, PYGB, and PYGL - are expressed in glial cells. Unlike PYGB and PYGL, PYGM is the only isoform regulated by Rac1. This specific regulation may confer a differential functional role compared with the other glycogen phosphorylases-PYGB and PYGL. The involvement of muscle glycogen phosphorylase in glial cells and its association with post-translational modifications (PTMs) of proteins through O-glycosylation is indeed a fascinating and emerging area of research. The dual role it plays in metabolic processes and the regulation of PTMs within the brain presents intriguing implications for various neurological conditions. Disruptions in the O-GlcNAcylation cycle and neurodegenerative diseases like Alzheimer's disease (AD) is particularly noteworthy. The alterations in O-GlcNAcylation levels of specific proteins, such as APP, c-Fos, and tau protein, highlight the intricate relationship between PTMs and AD. Understanding these processes and the regulatory function of muscle glycogen phosphorylase sheds light on its impact on protein function, signaling pathways, cellular homeostasis, neurological health, and potential interventions for brain-related conditions.
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Affiliation(s)
- Francisco Llavero
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, 3rd Floor, Barrio de Sarriena s/n, 48940 Leioa, Spain
| | - José L Zugaza
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, 3rd Floor, Barrio de Sarriena s/n, 48940 Leioa, Spain
- Department of Genetics, Physical Anthropology and Animal Physiology, Faculty of Science and Technology, UPV/EHU, Barrio de Sarriena s/n, 48940 Leioa, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
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Hu Y, Hruscha A, Pan C, Schifferer M, Schmidt MK, Nuscher B, Giera M, Kostidis S, Burhan Ö, van Bebber F, Edbauer D, Arzberger T, Haass C, Schmid B. Mis-localization of endogenous TDP-43 leads to ALS-like early-stage metabolic dysfunction and progressive motor deficits. Mol Neurodegener 2024; 19:50. [PMID: 38902734 PMCID: PMC11188230 DOI: 10.1186/s13024-024-00735-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 05/23/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND The key pathological signature of ALS/ FTLD is the mis-localization of endogenous TDP-43 from the nucleus to the cytoplasm. However, TDP-43 gain of function in the cytoplasm is still poorly understood since TDP-43 animal models recapitulating mis-localization of endogenous TDP-43 from the nucleus to the cytoplasm are missing. METHODS CRISPR/Cas9 technology was used to generate a zebrafish line (called CytoTDP), that mis-locates endogenous TDP-43 from the nucleus to the cytoplasm. Phenotypic characterization of motor neurons and the neuromuscular junction was performed by immunostaining, microglia were immunohistochemically localized by whole-mount tissue clearing and muscle ultrastructure was analyzed by scanning electron microscopy. Behavior was investigated by video tracking and quantitative analysis of swimming parameters. RNA sequencing was used to identify mis-regulated pathways with validation by molecular analysis. RESULTS CytoTDP fish have early larval phenotypes resembling clinical features of ALS such as progressive motor defects, neurodegeneration and muscle atrophy. Taking advantage of zebrafish's embryonic development that solely relys on yolk usage until 5 days post fertilization, we demonstrated that microglia proliferation and activation in the hypothalamus is independent from food intake. By comparing CytoTDP to a previously generated TDP-43 knockout line, transcriptomic analyses revealed that mis-localization of endogenous TDP-43, rather than TDP-43 nuclear loss of function, leads to early onset metabolic dysfunction. CONCLUSIONS The new TDP-43 model mimics the ALS/FTLD hallmark of progressive motor dysfunction. Our results suggest that functional deficits of the hypothalamus, the metabolic regulatory center, might be the primary cause of weight loss in ALS patients. Cytoplasmic gain of function of endogenous TDP-43 leads to metabolic dysfunction in vivo that are reminiscent of early ALS clinical non-motor metabolic alterations. Thus, the CytoTDP zebrafish model offers a unique opportunity to identify mis-regulated targets for therapeutic intervention early in disease progression.
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Affiliation(s)
- Yiying Hu
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Metabolic Biochemistry, Biomedical Centre (BMC), Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
- Munich Medical Research School (MMRS), Munich, Germany
| | - Alexander Hruscha
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Chenchen Pan
- Neurology Clinic and National Center for Tumor Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Martina Schifferer
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Michael K Schmidt
- Zentrum Für Neuropathologie, Ludwig-Maximilians University, Munich, Germany
| | - Brigitte Nuscher
- Metabolic Biochemistry, Biomedical Centre (BMC), Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
| | - Martin Giera
- Leiden University Medical Center, Leiden, Netherlands
| | | | - Özge Burhan
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Frauke van Bebber
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Metabolic Biochemistry, Biomedical Centre (BMC), Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Arzberger
- Zentrum Für Neuropathologie, Ludwig-Maximilians University, Munich, Germany
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- Metabolic Biochemistry, Biomedical Centre (BMC), Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Bettina Schmid
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.
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Rodrigues K, Batista-Silva H, de Moura KRS, Van Der Kraak G, Silva FRMB. Dibutyl phthalate disrupts energy metabolism and morphology in the gills and induces hepatotoxicity in zebrafish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2023; 49:883-893. [PMID: 37537493 DOI: 10.1007/s10695-023-01227-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 07/28/2023] [Indexed: 08/05/2023]
Abstract
This study investigated the acute effects of dibutyl phthalate (DBP) exposure on energy metabolism and gill histology in zebrafish (Danio rerio). The in vitro incubation of gill tissue with 10 μM DBP for 60 min altered tissue energy supply, as shown by decreased lactate content and lactate dehydrogenase (LDH) activity. Higher concentrations of DBP (100 μM and 1 mM) increased lactate content and LDH activity; however, they blocked glucose uptake, depleted the glycogen content in cellular stores, and induced injury to the gills, as measured by LDH release to the extracellular medium. In addition, in vivo exposure of fish to 1 pM DBP for 12 h induced liver damage by increasing alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) activities. Gill histology indicated hyperemia, lamellar fusion, lamellar telangiectasis, and necrosis. Data indicate that acute exposure of zebrafish gills to the higher DBP concentrations studied induces anaerobic cellular activity and high lactate production, causing gill damage, diminishing cell viability, and incurring liver dysfunction.
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Affiliation(s)
- Keyla Rodrigues
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Rua João Pio Duarte Silva, 241, Córrego Grande, CEP, Florianópolis, Santa Catarina, 88040-900, Brazil
| | - Hemily Batista-Silva
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Rua João Pio Duarte Silva, 241, Córrego Grande, CEP, Florianópolis, Santa Catarina, 88040-900, Brazil
| | - Kieiv Resende Sousa de Moura
- Departamento de Ciências Morfológicas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Glen Van Der Kraak
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Fátima Regina Mena Barreto Silva
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Rua João Pio Duarte Silva, 241, Córrego Grande, CEP, Florianópolis, Santa Catarina, 88040-900, Brazil.
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Mathomes RT, Koulas SM, Tsialtas I, Stravodimos G, Welsby PJ, Psarra AMG, Stasik I, Leonidas DD, Hayes JM. Multidisciplinary docking, kinetics and X-ray crystallography studies of baicalein acting as a glycogen phosphorylase inhibitor and determination of its' potential against glioblastoma in cellular models. Chem Biol Interact 2023; 382:110568. [PMID: 37277066 DOI: 10.1016/j.cbi.2023.110568] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/07/2023]
Abstract
Glycogen phosphorylase (GP) is the rate-determining enzyme in the glycogenolysis pathway. Glioblastoma (GBM) is amongst the most aggressive cancers of the central nervous system. The role of GP and glycogen metabolism in the context of cancer cell metabolic reprogramming is recognised, so that GP inhibitors may have potential treatment benefits. Here, baicalein (5,6,7-trihydroxyflavone) is studied as a GP inhibitor, and for its effects on glycogenolysis and GBM at the cellular level. The compound is revealed as a potent GP inhibitor against human brain GPa (Ki = 32.54 μM), human liver GPa (Ki = 8.77 μM) and rabbit muscle GPb (Ki = 5.66 μM) isoforms. It is also an effective inhibitor of glycogenolysis (IC50 = 119.6 μM), measured in HepG2 cells. Most significantly, baicalein demonstrated anti-cancer potential through concentration- and time-dependent decrease in cell viability for three GBM cell-lines (U-251 MG, U-87 MG, T98-G) with IC50 values of ∼20-55 μM (48- and 72-h). Its effectiveness against T98-G suggests potential against GBM with resistance to temozolomide (the first-line therapy) due to a positive O6-methylguanine-DNA methyltransferase (MGMT) status. The solved X-ray structure of rabbit muscle GP-baicalein complex will facilitate structure-based design of GP inhibitors. Further exploration of baicalein and other GP inhibitors with different isoform specificities against GBM is suggested.
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Affiliation(s)
- Rachel T Mathomes
- School of Pharmacy & Biomedical Sciences, University of Central Lancashire, Preston, PR1 2HE, United Kingdom
| | - Symeon M Koulas
- Department of Biochemistry & Biotechnology, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - Ioannis Tsialtas
- Department of Biochemistry & Biotechnology, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - George Stravodimos
- Department of Biochemistry & Biotechnology, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - Philip J Welsby
- Department of Postgraduate Medical Education, Edge Hill University, Ormskirk, L39 4QP, United Kingdom
| | - Anna-Maria G Psarra
- Department of Biochemistry & Biotechnology, University of Thessaly, Biopolis, 41500, Larissa, Greece
| | - Izabela Stasik
- School of Pharmacy & Biomedical Sciences, University of Central Lancashire, Preston, PR1 2HE, United Kingdom
| | - Demetres D Leonidas
- Department of Biochemistry & Biotechnology, University of Thessaly, Biopolis, 41500, Larissa, Greece.
| | - Joseph M Hayes
- School of Pharmacy & Biomedical Sciences, University of Central Lancashire, Preston, PR1 2HE, United Kingdom.
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Wang NK, Liu PK, Kong Y, Tseng YJ, Jenny LA, Nolan ND, Chen N, Wang HH, Hsu CW, Huang WC, Sparrow JR, Lin CS, Tsang SH. Spatiotemporal control of genome engineering in cone photoreceptors. Cell Biosci 2023; 13:119. [PMID: 37381060 PMCID: PMC10304375 DOI: 10.1186/s13578-023-01033-3] [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: 12/02/2022] [Accepted: 04/15/2023] [Indexed: 06/30/2023] Open
Abstract
BACKGROUND Cones are essential for color recognition, high resolution, and central vision; therefore cone death causes blindness. Understanding the pathophysiology of each cell type in the retina is key to developing therapies for retinal diseases. However, studying the biology of cone cells in the rod-dominant mammalian retina is particularly challenging. In this study, we used a bacterial artificial chromosome (BAC) recombineering method to knock in the "CreERT2" sequence into the Gnat2 and Arr3 genes, respectively and generated three novel inducible CreERT2 mice with different cone cell specificities. RESULTS These models (Gnat2CreERT2, Arr3T2ACreERT2, and Arr3P2ACreERT2) express temporally controllable Cre recombinase that achieves conditional alleles in cone photoreceptors. Cre-LoxP recombination can be induced as early as postnatal day (PD) two upon tamoxifen injection at varying efficiencies, ranging from 10 to 15% in Gnat2CreERT2, 40% in Arr3T2ACreERT2, and 100% in Arr3P2ACreERT2. Notably, knocking in the P2A-CreERT2 cassette does not affect cone cell morphology and functionality. Most cone-phototransduction enzymes, including Opsins, CNGA3, etc. are not altered except for a reduction in the Arr3 transcript. CONCLUSIONS The Arr3P2ACreERT2 mouse, an inducible cone-specific Cre driver, is a valuable line in studying cone cell biology, function, as well as its relationship with rod and other retinal cells. Moreover, the Cre activity can be induced by delivering tamoxifen intragastrically as early as PD2, which will be useful for studying retinal development or in rapid degenerative mouse models.
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Affiliation(s)
- Nan-Kai Wang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Vagelos College of Physicians and Surgeons, Columbia University, New York, USA.
| | - Pei-Kang Liu
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Yang Kong
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Yun-Ju Tseng
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Laura A Jenny
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Nicholas D Nolan
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Department of Biomedical Engineering, The Fu Foundation School of Engineering and Applied Science, Columbia University, New York, NY, 10027, USA
| | - Nelson Chen
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Faculty of Health Sciences, Queen's University, Kingston, ON, Canada
| | - Hung-Hsi Wang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- College of Arts and Sciences, University of Miami, Coral Gables, FL, USA
| | - Chun Wei Hsu
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Wan-Chun Huang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Janet R Sparrow
- Departments of Ophthalmology, Pathology and Cell Biology, Columbia University, New York, USA
| | - Chyuan-Sheng Lin
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Stephen H Tsang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Jonas Children's Vision Care, and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, USA.
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Barmpagiannos K, Theotokis P, Petratos S, Pagnin M, Einstein O, Kesidou E, Boziki M, Artemiadis A, Bakirtzis C, Grigoriadis N. The Diversity of Astrocyte Activation during Multiple Sclerosis: Potential Cellular Targets for Novel Disease Modifying Therapeutics. Healthcare (Basel) 2023; 11:healthcare11111585. [PMID: 37297725 DOI: 10.3390/healthcare11111585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Neuroglial cells, and especially astrocytes, constitute the most varied group of central nervous system (CNS) cells, displaying substantial diversity and plasticity during development and in disease states. The morphological changes exhibited by astrocytes during the acute and chronic stages following CNS injury can be characterized more precisely as a dynamic continuum of astrocytic reactivity. Different subpopulations of reactive astrocytes may be ascribed to stages of degenerative progression through their direct pathogenic influence upon neurons, neuroglia, the blood-brain barrier, and infiltrating immune cells. Multiple sclerosis (MS) constitutes an autoimmune demyelinating disease of the CNS. Despite the previously held notion that reactive astrocytes purely form the structured glial scar in MS plaques, their continued multifaceted participation in neuroinflammatory outcomes and oligodendrocyte and neuronal function during chronicity, suggest that they may be an integral cell type that can govern the pathophysiology of MS. From a therapeutic-oriented perspective, astrocytes could serve as key players to limit MS progression, once the integral astrocyte-MS relationship is accurately identified. This review aims toward delineating the current knowledge, which is mainly focused on immunomodulatory therapies of the relapsing-remitting form, while shedding light on uncharted approaches of astrocyte-specific therapies that could constitute novel, innovative applications once the role of specific subgroups in disease pathogenesis is clarified.
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Affiliation(s)
- Konstantinos Barmpagiannos
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
| | - Paschalis Theotokis
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
| | - Steven Petratos
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Maurice Pagnin
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Ofira Einstein
- Department of Physical Therapy, Faculty of Health Sciences, Ariel University, Ariel 40700, Israel
| | - Evangelia Kesidou
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
| | - Marina Boziki
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
| | | | - Christos Bakirtzis
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
| | - Nikolaos Grigoriadis
- Laboratory of Experimental Neurology and Neuroimmunology, Second Department of Neurology, Aristotle University of Thessaloniki, 54621 Thessaloniki, Greece
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Stulczewski D, Zgorzynska E, Dziedzic B, Wieczorek-Szukala K, Szafraniec K, Walczewska A. EPA stronger than DHA increases the mitochondrial membrane potential and cardiolipin levels but does not change the ATP level in astrocytes. Exp Cell Res 2023; 424:113491. [PMID: 36708860 DOI: 10.1016/j.yexcr.2023.113491] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 12/22/2022] [Accepted: 01/22/2023] [Indexed: 01/27/2023]
Abstract
Astrocytes are highly energy-consuming glial cells critical for metabolic support to neurons. A growing body of evidence suggests that mitochondrial dysfunction in astrocytes is involved in age-related neurodegenerative disorders and that fish oil, rich in docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, may alleviate cognition impairment in Parkinson's and Alzheimer's diseases. The present study examines the effect of DHA and EPA on mitochondrial membrane potential (MMP), apoptosis activation and ATP levels in astrocytes cultured in medium containing glucose or galactose, which limits oxidative phosphorylation (OXPHOS). MMP, expressed as the ratio of red to green JC-10 and MitoTracker fluorescence, increased in EPA-incubated cells in a dose dependent manner and was higher than in DHA-incubated astrocytes, also after uncoupling of OXPHOS by carbonyl cyanide 3-chlorophenylhydrazone (CCCP). In cells cultured in glucose and galactose medium mitochondrial hyperpolarization had no impact on intracellular ATP level. Furthermore, both EPA and DHA elevated mitochondrial cardiolipin content, however only EPA did so in a dose-dependent manner and reduced apoptosis which was analyzed by flow cytometry.
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Affiliation(s)
- Dawid Stulczewski
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Emilia Zgorzynska
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland.
| | - Barbara Dziedzic
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | | | - Kacper Szafraniec
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
| | - Anna Walczewska
- Department of Cell-to-Cell Communication, Medical University of Lodz, Mazowiecka 6/8, 92-215, Lodz, Poland
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9
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Bastian C, Zerimech S, Nguyen H, Doherty C, Franke C, Faris A, Quinn J, Baltan S. Aging astrocytes metabolically support aging axon function by proficiently regulating astrocyte-neuron lactate shuttle. Exp Neurol 2022; 357:114173. [PMID: 35863500 PMCID: PMC11218845 DOI: 10.1016/j.expneurol.2022.114173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 06/23/2022] [Accepted: 07/14/2022] [Indexed: 11/19/2022]
Abstract
The astrocyte-neuron lactate shuttle (ANLS) is an essential metabolic support system that uptakes glucose, stores it as glycogen in astrocytes, and provides glycogen-derived lactate for axonal function. Aging intrinsically increases the vulnerability of white matter (WM) to injury. Therefore, we investigated the regulation of this shuttle to understand vascular-glial metabolic coupling to support axonal function during aging in two different WM tracts. Aging astrocytes displayed larger cell bodies and thicker horizontal processes in contrast to thinner vertically oriented processes of young astrocytes. Aging axons recovered less following aglycemia in mouse optic nerves (MONs) compared to young axons, although providing lactate during aglycemia equally supported young and aging axonal function. Incubating MONs in high glucose to upregulate glycogen stores in astrocytes delayed loss of function during aglycemia and improved recovery in both young and aging axons. Providing lactate during recovery from aglycemia unmasked a metabolic switch from glucose to lactate in aging axons. Young and aging corpus callosum consisting of a mixture of myelinated and unmyelinated axons sustained their function fully when lactate was available during aglycemia and surprisingly showed a greater resilience to aglycemia compared to fully myelinated axons of optic nerve. We conclude that lactate is a universal substrate for axons independent of their myelination content and age.
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Affiliation(s)
- Chinthasagar Bastian
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America
| | - Sarah Zerimech
- Anesthesia and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, United States of America
| | - Hung Nguyen
- Anesthesia and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, United States of America
| | - Christine Doherty
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America
| | - Caroline Franke
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America
| | - Anna Faris
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America
| | - John Quinn
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America
| | - Selva Baltan
- Anesthesia and Perioperative Medicine, Oregon Health and Science University, Portland, OR 97239, United States of America; Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH 441952, United States of America.
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Xue X, Liu B, Hu J, Bian X, Lou S. The potential mechanisms of lactate in mediating exercise-enhanced cognitive function: a dual role as an energy supply substrate and a signaling molecule. Nutr Metab (Lond) 2022; 19:52. [PMID: 35907984 PMCID: PMC9338682 DOI: 10.1186/s12986-022-00687-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 07/18/2022] [Indexed: 11/12/2022] Open
Abstract
Lactate has previously been considered a metabolic waste and is mainly involved in exercise-induced fatigue. However, recent studies have found that lactate may be a mediator of the beneficial effects of exercise on brain health. Lactate plays a dual role as an energy supply substrate and a signaling molecule in this process. On the one hand, astrocytes can uptake circulating glucose or degrade glycogen for glycolysis to produce lactate, which is released into the extracellular space. Neurons can uptake extracellular lactate as an important supplement to their energy metabolism substrates, to meet the demand for large amounts of energy when synaptic activity is enhanced. Thus, synaptic activity and energy transfer show tight metabolic coupling. On the other hand, lactate acts as a signaling molecule to activate downstream signaling transduction pathways by specific receptors, inducing the expression of immediate early genes and cerebral angiogenesis. Moderate to high-intensity exercise not only increases lactate production and accumulation in muscle and blood but also promotes the uptake of skeletal muscle-derived lactate by the brain and enhances aerobic glycolysis to increase brain-derived lactate production. Furthermore, exercise regulates the expression or activity of transporters and enzymes involved in the astrocyte-neuron lactate shuttle to maintain the efficiency of this process; exercise also activates lactate receptor HCAR1, thus affecting brain plasticity. Rethinking the role of lactate in cognitive function and the regulatory effect of exercise is the main focus and highlights of the review. This may enrich the theoretical basis of lactate-related to promote brain health during exercise, and provide new perspectives for promoting a healthy aging strategy.
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Affiliation(s)
- Xiangli Xue
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, 200438, China.,Shanghai Frontiers Science Research Base of Exercise and Metabolic Health, Shanghai University of Sport, Shanghai, 200438, China
| | - Beibei Liu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, 200438, China.,Department of Clinical Medicine, Weifang Medical College, Weifang, 261053, Shandong, China
| | - Jingyun Hu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, 200438, China
| | - Xuepeng Bian
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, 200438, China
| | - Shujie Lou
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, 200438, China. .,Shanghai Frontiers Science Research Base of Exercise and Metabolic Health, Shanghai University of Sport, Shanghai, 200438, China.
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11
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Miller AL, Fuller-Carter PI, Masarini K, Samardzija M, Carter KW, Rashwan R, Lim XR, Brunet AA, Chopra A, Ram R, Grimm C, Ueffing M, Carvalho LS, Trifunović D. Increased H3K27 trimethylation contributes to cone survival in a mouse model of cone dystrophy. Cell Mol Life Sci 2022; 79:409. [PMID: 35810394 PMCID: PMC9271452 DOI: 10.1007/s00018-022-04436-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 11/30/2022]
Abstract
Inherited retinal diseases (IRDs) are a heterogeneous group of blinding disorders, which result in dysfunction or death of the light-sensing cone and rod photoreceptors. Despite individual IRDs (Inherited retinal disease) being rare, collectively, they affect up to 1:2000 people worldwide, causing a significant socioeconomic burden, especially when cone-mediated central vision is affected. This study uses the Pde6ccpfl1 mouse model of achromatopsia, a cone-specific vision loss IRD (Inherited retinal disease), to investigate the potential gene-independent therapeutic benefits of a histone demethylase inhibitor GSK-J4 on cone cell survival. We investigated the effects of GSK-J4 treatment on cone cell survival in vivo and ex vivo and changes in cone-specific gene expression via single-cell RNA sequencing. A single intravitreal GSK-J4 injection led to transcriptional changes in pathways involved in mitochondrial dysfunction, endoplasmic reticulum stress, among other key epigenetic pathways, highlighting the complex interplay between methylation and acetylation in healthy and diseased cones. Furthermore, continuous administration of GSK-J4 in retinal explants increased cone survival. Our results suggest that IRD (Inherited retinal disease)-affected cones respond positively to epigenetic modulation of histones, indicating the potential of this approach in developing a broad class of novel therapies to slow cone degeneration.
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Affiliation(s)
- Annie L Miller
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Paula I Fuller-Carter
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia
| | - Klaudija Masarini
- Institute for Ophthalmic Research, Tübingen University, Elfriede-Aulhorn-Straße 7, 72076, Tübingen, Germany
| | - Marijana Samardzija
- Lab for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zürich, University of Zürich, Zurich, Switzerland
| | - Kim W Carter
- Analytical Computing Solutions, Willetton, WA, 6155, Australia
| | - Rabab Rashwan
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia
- Department of Microbiology and Immunology, Faculty of Medicine, Minia University, Minia, Egypt
| | - Xin Ru Lim
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Alicia A Brunet
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Abha Chopra
- Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, WA, Australia
- Department of Medicine, Vanderbilt University Medical Centre, Nashville, TN, USA
| | - Ramesh Ram
- Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, WA, Australia
| | - Christian Grimm
- Lab for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zürich, University of Zürich, Zurich, Switzerland
| | - Marius Ueffing
- Institute for Ophthalmic Research, Tübingen University, Elfriede-Aulhorn-Straße 7, 72076, Tübingen, Germany
| | - Livia S Carvalho
- Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, 2 Verdun Street, Nedlands, WA, 6009, Australia.
- Centre for Ophthalmology and Visual Science, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia.
| | - Dragana Trifunović
- Institute for Ophthalmic Research, Tübingen University, Elfriede-Aulhorn-Straße 7, 72076, Tübingen, Germany.
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12
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Jurga AM, Paleczna M, Kadluczka J, Kuter KZ. Beyond the GFAP-Astrocyte Protein Markers in the Brain. Biomolecules 2021; 11:biom11091361. [PMID: 34572572 PMCID: PMC8468264 DOI: 10.3390/biom11091361] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/13/2022] Open
Abstract
The idea of central nervous system as one-man band favoring neurons is long gone. Now we all are aware that neurons and neuroglia are team players and constant communication between those various cell types is essential to maintain functional efficiency and a quick response to danger. Here, we summarize and discuss known and new markers of astroglial multiple functions, their natural heterogeneity, cellular interactions, aging and disease-induced dysfunctions. This review is focused on newly reported facts regarding astrocytes, which are beyond the old stereotypes. We present an up-to-date list of marker proteins used to identify a broad spectrum of astroglial phenotypes related to the various physiological and pathological nervous system conditions. The aim of this review is to help choose markers that are well-tailored for specific needs of further experimental studies, precisely recognizing differential glial phenotypes, or for diagnostic purposes. We hope it will help to categorize the functional and structural diversity of the astroglial population and ease a clear readout of future experimental results.
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13
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Migocka-Patrzałek M, Elias M. Muscle Glycogen Phosphorylase and Its Functional Partners in Health and Disease. Cells 2021; 10:cells10040883. [PMID: 33924466 PMCID: PMC8070155 DOI: 10.3390/cells10040883] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 02/07/2023] Open
Abstract
Glycogen phosphorylase (PG) is a key enzyme taking part in the first step of glycogenolysis. Muscle glycogen phosphorylase (PYGM) differs from other PG isoforms in expression pattern and biochemical properties. The main role of PYGM is providing sufficient energy for muscle contraction. However, it is expressed in tissues other than muscle, such as the brain, lymphoid tissues, and blood. PYGM is important not only in glycogen metabolism, but also in such diverse processes as the insulin and glucagon signaling pathway, insulin resistance, necroptosis, immune response, and phototransduction. PYGM is implicated in several pathological states, such as muscle glycogen phosphorylase deficiency (McArdle disease), schizophrenia, and cancer. Here we attempt to analyze the available data regarding the protein partners of PYGM to shed light on its possible interactions and functions. We also underline the potential for zebrafish to become a convenient and applicable model to study PYGM functions, especially because of its unique features that can complement data obtained from other approaches.
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14
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Pfeiffer-Guglielmi B, Jansen RP. The Motor Neuron-Like Cell Line NSC-34 and Its Parent Cell Line N18TG2 Have Glycogen that is Degraded Under Cellular Stress. Neurochem Res 2021; 46:1567-1576. [PMID: 33786720 PMCID: PMC8084819 DOI: 10.1007/s11064-021-03297-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/07/2021] [Accepted: 03/08/2021] [Indexed: 11/24/2022]
Abstract
Brain glycogen has a long and versatile history: Primarily regarded as an evolutionary remnant, it was then thought of as an unspecific emergency fuel store. A dynamic role for glycogen in normal brain function has been proposed later but exclusively attributed to astrocytes, its main storage site. Neuronal glycogen had long been neglected, but came into focus when sensitive technical methods allowed quantification of glycogen at low concentration range and the detection of glycogen metabolizing enzymes in cells and cell lysates. Recently, an active role of neuronal glycogen and even its contribution to neuronal survival could be demonstrated. We used the neuronal cell lines NSC-34 and N18TG2 and could demonstrate that they express the key-enzymes of glycogen metabolism, glycogen phosphorylase and glycogen synthase and contain glycogen which is mobilized on glucose deprivation and elevated potassium concentrations, but not by hormones stimulating cAMP formation. Conditions of metabolic stress, namely hypoxia, oxidative stress and pH lowering, induce glycogen degradation. Our studies revealed that glycogen can contribute to the energy supply of neuronal cell lines in situations of metabolic stress. These findings shed new light on the so far neglected role of neuronal glycogen. The key-enzyme in glycogen degradation is glycogen phosphorylase. Neurons express only the brain isoform of the enzyme that is supposed to be activated primarily by the allosteric activator AMP and less by covalent phosphorylation via the cAMP cascade. Our results indicate that neuronal glycogen is not degraded upon hormone action but by factors lowering the energy charge of the cells directly.
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Affiliation(s)
- Brigitte Pfeiffer-Guglielmi
- Interfaculty Institute for Biochemistry, University of Tübingen, Auf der Morgenstelle 34, 72076, Tübingen, Germany.
| | - Ralf-Peter Jansen
- Interfaculty Institute for Biochemistry, University of Tübingen, Auf der Morgenstelle 34, 72076, Tübingen, Germany
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15
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The Suitability of Glioblastoma Cell Lines as Models for Primary Glioblastoma Cell Metabolism. Cancers (Basel) 2020; 12:cancers12123722. [PMID: 33322454 PMCID: PMC7764800 DOI: 10.3390/cancers12123722] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 12/21/2022] Open
Abstract
Simple Summary Glioblastoma (GBM) is a deadly brain tumour with no effective treatments. Recently, new treatments which target the cancer’s unique metabolic properties are beginning to emerge. However, this preclinical research is commonly undertaken in human cell lines which poorly recapitulate the properties of the cancer in situ. This study has examined the metabolic properties of five commonly used GBM cell lines in comparison to healthy brain and GBM tissue. While no cell line faithfully recapitulates GBM, certain lines are useful for aspects of metabolic analysis in GBM cells. We identified three cell lines which accurately reflect the mitochondrial metabolism of GBM tumours, and one cell line suited for studies into glycolysis. In addition to providing detailed metabolic profiles of these commonly used cell lines, this research can guide preclinical experiments to assess the efficacy of desperately needed, novel therapeutics for GBM. Abstract In contrast to most non-malignant tissue, cells comprising the brain tumour glioblastoma (GBM) preferentially utilise glycolysis for metabolism via “the Warburg effect”. Research into therapeutics targeting the disease’s highly glycolytic state offer a promising avenue to improve patient survival. These studies often employ GBM cell lines for in vitro studies which translate poorly to the in vivo patient context. The metabolic traits of five of the most used GBM cell lines were assessed and compared to primary GBM and matched, healthy brain tissue. In patient-derived GBM cell lines, the basal mitochondrial rate (p = 0.043) and ATP-linked respiration (p < 0.001) were lower than primary adjacent normal cells from the same patient, while reserve capacity (p = 0.037) and Krebs cycle capacity (p = 0.002) were higher. Three cell lines, U251MG, U373MG and D54, replicate the mitochondrial metabolism of primary GBM cells. Surprisingly, glycolytic capacity is not different between healthy and GBM tissue. The T98G cell line recapitulated glycolysis-related metabolic parameters of the primary GBM cells and is recommended for research relating to glycolysis. These findings can guide preclinical research into the development of novel therapeutics targeting metabolic pathways in GBM.
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16
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Verhoog QP, Holtman L, Aronica E, van Vliet EA. Astrocytes as Guardians of Neuronal Excitability: Mechanisms Underlying Epileptogenesis. Front Neurol 2020; 11:591690. [PMID: 33324329 PMCID: PMC7726323 DOI: 10.3389/fneur.2020.591690] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are key homeostatic regulators in the central nervous system and play important roles in physiology. After brain damage caused by e.g., status epilepticus, traumatic brain injury, or stroke, astrocytes may adopt a reactive phenotype. This process of reactive astrogliosis is important to restore brain homeostasis. However, persistent reactive astrogliosis can be detrimental for the brain and contributes to the development of epilepsy. In this review, we will focus on physiological functions of astrocytes in the normal brain as well as pathophysiological functions in the epileptogenic brain, with a focus on acquired epilepsy. We will discuss the role of astrocyte-related processes in epileptogenesis, including reactive astrogliosis, disturbances in energy supply and metabolism, gliotransmission, and extracellular ion concentrations, as well as blood-brain barrier dysfunction and dysregulation of blood flow. Since dysfunction of astrocytes can contribute to epilepsy, we will also discuss their role as potential targets for new therapeutic strategies.
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Affiliation(s)
- Quirijn P. Verhoog
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Linda Holtman
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Erwin A. van Vliet
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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17
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Bernaus A, Blanco S, Sevilla A. Glia Crosstalk in Neuroinflammatory Diseases. Front Cell Neurosci 2020; 14:209. [PMID: 32848613 PMCID: PMC7403442 DOI: 10.3389/fncel.2020.00209] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 06/15/2020] [Indexed: 12/11/2022] Open
Abstract
Neuroinflammation constitutes a fundamental cellular process to signal the loss of brain homeostasis. Glial cells play a central role in orchestrating these neuroinflammation processes in both deleterious and beneficial ways. These cellular responses depend on their intercellular interactions with neurons, astrocytes, the blood–brain barrier (BBB), and infiltrated T cells in the central nervous system (CNS). However, this intercellular crosstalk seems to be activated by specific stimuli for each different neurological scenario. This review summarizes key studies linking neuroinflammation with certain neurodegenerative diseases such as Alzheimer disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) and for the development of better therapeutic strategies based on immunomodulation.
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Affiliation(s)
- Ada Bernaus
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Sandra Blanco
- Molecular Mechanisms Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Ana Sevilla
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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18
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Huang PC, Liu TY, Hu MY, Casties I, Tseng YC. Energy and nitrogenous waste from glutamate/glutamine catabolism facilitates acute osmotic adjustment in non-neuroectodermal branchial cells. Sci Rep 2020; 10:9460. [PMID: 32528019 PMCID: PMC7289822 DOI: 10.1038/s41598-020-65913-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 05/12/2020] [Indexed: 11/30/2022] Open
Abstract
Maintenance of homeostasis is one of the most important physiological responses for animals upon osmotic perturbations. Ionocytes of branchial epithelia are the major cell types responsible for active ion transport, which is mediated by energy-consuming ion pumps (e.g., Na+-K+-ATPase, NKA) and secondary active transporters. Consequently, in addition to osmolyte adjustments, sufficient and immediate energy replenishment is essenttableial for acclimation to osmotic changes. In this study, we propose that glutamate/glutamine catabolism and trans-epithelial transport of nitrogenous waste may aid euryhaline teleosts Japanese medaka (Oryzias latipes) during acclimation to osmotic changes. Glutamate family amino acid contents in gills were increased by hyperosmotic challenge along an acclimation period of 72 hours. This change in amino acids was accompanied by a stimulation of putative glutamate/glutamine transporters (Eaats, Sat) and synthesis enzymes (Gls, Glul) that participate in regulating glutamate/glutamine cycling in branchial epithelia during acclimation to hyperosmotic conditions. In situ hybridization of glutaminase and glutamine synthetase in combination with immunocytochemistry demonstrate a partial colocalization of olgls1a and olgls2 but not olglul with Na+/K+-ATPase-rich ionocytes. Also for the glutamate and glutamine transporters colocalization with ionocytes was found for oleaat1, oleaat3, and olslc38a4, but not oleaat2. Morpholino knock-down of Sat decreased Na+ flux from the larval epithelium, demonstrating the importance of glutamate/glutamine transport in osmotic regulation. In addition to its role as an energy substrate, glutamate deamination produces NH4+, which may contribute to osmolyte production; genes encoding components of the urea production cycle, including carbamoyl phosphate synthetase (CPS) and ornithine transcarbamylase (OTC), were upregulated under hyperosmotic challenges. Based on these findings the present work demonstrates that the glutamate/glutamine cycle and subsequent transepithelial transport of nitrogenous waste in branchial epithelia represents an essential component for the maintenance of ionic homeostasis under a hyperosmotic challenge.
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Affiliation(s)
- Pei-Chen Huang
- Marine Research Station, Institute of Cellular and organismic Biology, Academia Sinica, I-Lan County, Taiwan (ROC)
| | - Tzu-Yen Liu
- Marine Research Station, Institute of Cellular and organismic Biology, Academia Sinica, I-Lan County, Taiwan (ROC)
| | - Marian Y Hu
- Institute of Physiology, Christian-Albrechts University Kiel, Kiel, Germany
| | - Isabel Casties
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Yung-Che Tseng
- Marine Research Station, Institute of Cellular and organismic Biology, Academia Sinica, I-Lan County, Taiwan (ROC).
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19
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A thermodynamic function of glycogen in brain and muscle. Prog Neurobiol 2020; 189:101787. [PMID: 32151532 DOI: 10.1016/j.pneurobio.2020.101787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/30/2020] [Accepted: 03/03/2020] [Indexed: 11/20/2022]
Abstract
Brain and muscle glycogen are generally thought to function as local glucose reserves, for use during transient mismatches between glucose supply and demand. However, quantitative measures show that glucose supply is likely never rate-limiting for energy metabolism in either brain or muscle under physiological conditions. These tissues nevertheless do utilize glycogen during increased energy demand, despite the availability of free glucose, and despite the ATP cost of cycling glucose through glycogen polymer. This seemingly wasteful process can be explained by considering the effect of glycogenolysis on the amount of energy obtained from ATP (ΔG'ATP). The amount of energy obtained from ATP is reduced by elevations in inorganic phosphate (Pi). Glycogen utilization sequesters Pi in the glycogen phosphorylase reaction and in downstream phosphorylated glycolytic intermediates, thereby buffering Pi elevations and maximizing energy yield at sites of rapid ATP consumption. This thermodynamic effect of glycogen may be particularly important in the narrow, spatially constrained astrocyte processes that ensheath neuronal synapses and in cells such as astrocytes and myocytes that release Pi from phosphocreatine during energy demand. The thermodynamic effect may also explain glycolytic super-compensation in brain when glycogen is not available, and aspects of exercise physiology in muscle glycogen phosphorylase deficiency (McArdle disease).
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20
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McArdle Disease: New Insights into Its Underlying Molecular Mechanisms. Int J Mol Sci 2019; 20:ijms20235919. [PMID: 31775340 PMCID: PMC6929006 DOI: 10.3390/ijms20235919] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/14/2019] [Accepted: 11/21/2019] [Indexed: 01/05/2023] Open
Abstract
McArdle disease, also known as glycogen storage disease type V (GSDV), is characterized by exercise intolerance, the second wind phenomenon, and high serum creatine kinase activity. Here, we recapitulate PYGM mutations in the population responsible for this disease. Traditionally, McArdle disease has been considered a metabolic myopathy caused by the lack of expression of the muscle isoform of the glycogen phosphorylase (PYGM). However, recent findings challenge this view, since it has been shown that PYGM is present in other tissues than the skeletal muscle. We review the latest studies about the molecular mechanism involved in glycogen phosphorylase activity regulation. Further, we summarize the expression and functional significance of PYGM in other tissues than skeletal muscle both in health and McArdle disease. Furthermore, we examine the different animal models that have served as the knowledge base for better understanding of McArdle disease. Finally, we give an overview of the latest state-of-the-art clinical trials currently being carried out and present an updated view of the current therapies.
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21
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Quantification of Changes in Visual Function During Disease Development in a Mouse Model of Pigmentary Glaucoma. J Glaucoma 2019; 27:828-841. [PMID: 30001268 DOI: 10.1097/ijg.0000000000001024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE We investigated the relationship between visual parameters that are commonly affected during glaucomatous disease progression with functional measures of retina physiology using electroretinography and behavioral measures of visual function in a mouse model of glaucoma. Electroretinogram components measuring retinal ganglion cell (RGC) responses were determined using the non-invasive Ganzfeld flash electroretinography (fERG) to assess RGC loss in a mouse model of glaucoma. METHODS Intraocular pressure (IOP), behaviorally assessed measures of visual function, namely visual acuity and contrast sensitivity as well as fERG responses were recorded in 4- and 11-month-old male DBA/2 mice. Scotopic threshold response (STR) and photopic negative response components as well as oscillatory potentials (OPs) were isolated from fERG responses and correlated with IOP, optomotor reflex measurements, and RGC counts. RESULTS The 11-month-old DBA/2 mice had significantly elevated IOP, reduced visual performance, as assessed behaviorally, significant RGC loss, deficits in standardized fERG responses, reduced STRs, and differences in OP amplitudes and latencies, when compared with 4-month-old mice of the same strain. STRs and OPs correlated with some visual and physiological parameters. In addition, elevated IOP and RGC loss correlated positively with measures of visual function, specifically with surrogate measures of RGC function derived from fERG. CONCLUSIONS Our data suggest that RGC function as well as interactions of RGCs with other retinal cell types is impaired during glaucoma. In addition, a later OP wavelet denoted as OP4 in this study was identified as a very reproducible indicator of loss of visual function in the glaucoma mouse model.
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22
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Descalzi G, Gao V, Steinman MQ, Suzuki A, Alberini CM. Lactate from astrocytes fuels learning-induced mRNA translation in excitatory and inhibitory neurons. Commun Biol 2019; 2:247. [PMID: 31286064 PMCID: PMC6606643 DOI: 10.1038/s42003-019-0495-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/05/2019] [Indexed: 12/12/2022] Open
Abstract
Glycogenolysis and lactate transport from astrocytes to neurons is required for long-term memory formation, but the role of this lactate is poorly understood. Here we show that the Krebs cycle substrates pyruvate and ketone body B3HB can functionally replace lactate in rescuing memory impairment caused by inhibition of glycogenolysis or expression knockdown of glia monocarboxylate transporters (MCTs) 1 and 4 in the dorsal hippocampus of rats. In contrast, either metabolite is unable to rescue memory impairment produced by expression knockdown of MCT2, which is selectively expressed by neurons, indicating that a critical role of astrocytic lactate is to provide energy for neuronal responses required for long-term memory. These responses include learning-induced mRNA translation in both excitatory and inhibitory neurons, as well as expression of Arc/Arg3.1. Thus, astrocytic lactate acts as an energy substrate to fuel learning-induced de novo neuronal translation critical for long-term memory.
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Affiliation(s)
- Giannina Descalzi
- Center for Neural Science, New York University, New York, NY 10003 USA
| | - Virginia Gao
- Center for Neural Science, New York University, New York, NY 10003 USA
| | | | - Akinobu Suzuki
- Center for Neural Science, New York University, New York, NY 10003 USA
- Present Address: Department of Biochemistry, Faculty of Medicine, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194 Japan
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23
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Wu L, Wong CP, Swanson RA. Methodological considerations for studies of brain glycogen. J Neurosci Res 2019; 97:914-922. [PMID: 30892752 DOI: 10.1002/jnr.24412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 01/02/2023]
Abstract
Glycogen stores in the brain have been recognized for decades, but the underlying physiological function of this energy reserve remains elusive. This uncertainty stems in part from several technical challenges inherent in the study of brain glycogen metabolism. These include low glycogen content in the brain, non-homogeneous labeling of glycogen by radiotracers, rapid glycogenolysis during postmortem tissue handling, and effects of the stress response on brain glycogen turnover. Here we briefly review the aspects of the glycogen structure and metabolism that bear on these technical challenges and present ways they can be addressed.
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Affiliation(s)
- Long Wu
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, San Francisco, California
| | - Candance P Wong
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, San Francisco, California
| | - Raymond A Swanson
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, San Francisco, California
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Morita M, Ikeshima-Kataoka H, Kreft M, Vardjan N, Zorec R, Noda M. Metabolic Plasticity of Astrocytes and Aging of the Brain. Int J Mol Sci 2019; 20:ijms20040941. [PMID: 30795555 PMCID: PMC6413111 DOI: 10.3390/ijms20040941] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/17/2019] [Accepted: 02/18/2019] [Indexed: 01/03/2023] Open
Abstract
As part of the blood-brain-barrier, astrocytes are ideally positioned between cerebral vasculature and neuronal synapses to mediate nutrient uptake from the systemic circulation. In addition, astrocytes have a robust enzymatic capacity of glycolysis, glycogenesis and lipid metabolism, managing nutrient support in the brain parenchyma for neuronal consumption. Here, we review the plasticity of astrocyte energy metabolism under physiologic and pathologic conditions, highlighting age-dependent brain dysfunctions. In astrocytes, glycolysis and glycogenesis are regulated by noradrenaline and insulin, respectively, while mitochondrial ATP production and fatty acid oxidation are influenced by the thyroid hormone. These regulations are essential for maintaining normal brain activities, and impairments of these processes may lead to neurodegeneration and cognitive decline. Metabolic plasticity is also associated with (re)activation of astrocytes, a process associated with pathologic events. It is likely that the recently described neurodegenerative and neuroprotective subpopulations of reactive astrocytes metabolize distinct energy substrates, and that this preference is supposed to explain some of their impacts on pathologic processes. Importantly, physiologic and pathologic properties of astrocytic metabolic plasticity bear translational potential in defining new potential diagnostic biomarkers and novel therapeutic targets to mitigate neurodegeneration and age-related brain dysfunctions.
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Affiliation(s)
- Mitsuhiro Morita
- Department of Biology, Graduate School of Sciences, Kobe University, 657-8501 Kobe, Japan.
| | - Hiroko Ikeshima-Kataoka
- Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Marko Kreft
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia.
- Department of Biology, Biotechnical Faculty University of Ljubljana, 1000 Ljubljana, Slovenia.
| | - Nina Vardjan
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia.
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, 1000 Ljubljana, Slovenia.
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia.
| | - Mami Noda
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
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Glycogenolysis in Cerebral Cortex During Sensory Stimulation, Acute Hypoglycemia, and Exercise: Impact on Astrocytic Energetics, Aerobic Glycolysis, and Astrocyte-Neuron Interactions. ADVANCES IN NEUROBIOLOGY 2019; 23:209-267. [DOI: 10.1007/978-3-030-27480-1_8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Dienel GA, Carlson GM. Major Advances in Brain Glycogen Research: Understanding of the Roles of Glycogen Have Evolved from Emergency Fuel Reserve to Dynamic, Regulated Participant in Diverse Brain Functions. ADVANCES IN NEUROBIOLOGY 2019; 23:1-16. [DOI: 10.1007/978-3-030-27480-1_1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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27
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The Structure and the Regulation of Glycogen Phosphorylases in Brain. ADVANCES IN NEUROBIOLOGY 2019; 23:125-145. [DOI: 10.1007/978-3-030-27480-1_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Bastian C, Quinn J, Doherty C, Franke C, Faris A, Brunet S, Baltan S. Role of Brain Glycogen During Ischemia, Aging and Cell-to-Cell Interactions. ADVANCES IN NEUROBIOLOGY 2019; 23:347-361. [PMID: 31667815 PMCID: PMC11218841 DOI: 10.1007/978-3-030-27480-1_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The astrocyte-neuron lactate transfer shuttle (ANLS) is one of the important metabolic systems that provides a physiological infrastructure for glia-neuronal interactions where specialized architectural organization supports the function. Perivascular astrocyte end-feet take up glucose via glucose transporter 1 to actively regulate glycogen stores, such that high ambient glucose upregulates glycogen and low levels of glucose deplete glycogen stores. A rapid breakdown of glycogen into lactate during increased neuronal activity or low glucose conditions becomes essential for maintaining axon function. However, it fails to benefit axon function during an ischemic episode in white matter (WM). Aging causes a remarkable change in astrocyte architecture characterized by thicker, larger processes oriented parallel to axons, as opposed to vertically-transposing processes. Subsequently, aging axons become more vulnerable to depleted glycogen, although aging axons can use lactate as efficiently as young axons. Lactate equally supports function during aglycemia in corpus callosum (CC), which consists of a mixture of myelinated and unmyelinated axons. Moreover, axon function in CC shows greater resilience to a lack of glucose compared to optic nerve, although both WM tracts show identical recovery after aglycemic injury. Interestingly, emerging evidence implies that a lactate transport system is not exclusive to astrocytes, as oligodendrocytes support the axons they myelinate, suggesting another metabolic coupling pathway in WM. Future studies are expected to unravel the details of oligodendrocyte-axon lactate metabolic coupling to establish that all WM components metabolically cooperate and that lactate may be the universal metabolite to sustain central nervous system function.
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Affiliation(s)
- Chinthasagar Bastian
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - John Quinn
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Christine Doherty
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Caroline Franke
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Anna Faris
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Sylvain Brunet
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Selva Baltan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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Coggan JS, Keller D, Calì C, Lehväslaiho H, Markram H, Schürmann F, Magistretti PJ. Norepinephrine stimulates glycogenolysis in astrocytes to fuel neurons with lactate. PLoS Comput Biol 2018; 14:e1006392. [PMID: 30161133 PMCID: PMC6160207 DOI: 10.1371/journal.pcbi.1006392] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 09/27/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022] Open
Abstract
The mechanism of rapid energy supply to the brain, especially to accommodate the heightened metabolic activity of excited states, is not well-understood. We explored the role of glycogen as a fuel source for neuromodulation using the noradrenergic stimulation of glia in a computational model of the neural-glial-vasculature ensemble (NGV). The detection of norepinephrine (NE) by the astrocyte and the coupled cAMP signal are rapid and largely insensitive to the distance of the locus coeruleus projection release sites from the glia, implying a diminished impact for volume transmission in high affinity receptor transduction systems. Glucosyl-conjugated units liberated from glial glycogen by NE-elicited cAMP second messenger transduction winds sequentially through the glycolytic cascade, generating robust increases in NADH and ATP before pyruvate is finally transformed into lactate. This astrocytic lactate is rapidly exported by monocarboxylate transporters to the associated neuron, demonstrating that the astrocyte-to-neuron lactate shuttle activated by glycogenolysis is a likely fuel source for neuromodulation and enhanced neural activity. Altogether, the energy supply for both astrocytes and neurons can be supplied rapidly by glycogenolysis upon neuromodulatory stimulus. Although efficient compared to computers, the human brain utilizes energy at 10-fold the rate of other organs by mass. How the brain is supplied with sufficient on-demand energy to support its activity in the absence of neuronal storage capacity remains unknown. Neurons are not capable of meeting their own energy requirements, instead energy supply in the brain is managed by an oligocellular cartel composed of neurons, glia and the local vasculature (NGV), wherein glia can provide the ergogenic metabolite lactate to the neuron in a process called the astrocyte-to-neuron shuttle (ANLS). The only means of energy storage in the brain is glycogen, a polymerized form of glucose that is localized largely to astrocytes, but its exact role and conditions of use are not clear. In this computational model we show that neuromodulatory stimulation by norepinephrine induces astrocytes to recover glucosyl subunits from glycogen for use in a glycolytic process that favors the production of lactate. The ATP and NADH produced support metabolism in the astrocyte while the lactate is exported to feed the neuron. Thus, rapid energy demands by both neurons and glia in a stimulated brain can be met by glycogen mobilization.
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Affiliation(s)
- Jay S. Coggan
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- * E-mail: (JSC); (PJM)
| | - Daniel Keller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Corrado Calì
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Heikki Lehväslaiho
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Felix Schürmann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Pierre J. Magistretti
- Blue Brain Project, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
- * E-mail: (JSC); (PJM)
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Pang JJ, Yang Z, Jacoby RA, Wu SM. Cone synapses in mammalian retinal rod bipolar cells. J Comp Neurol 2018; 526:1896-1909. [PMID: 29667170 PMCID: PMC6031453 DOI: 10.1002/cne.24456] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 01/25/2023]
Abstract
Some mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2 ), but anatomical evidence for mammalian cone-RBC contacts has been sparse. We examined anatomical cone-RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno-markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)-opsin, whereas baboon cones were positive for calbindin D-28k. All synapses in the outer plexiform layer were labeled for synaptic vesicle protein 2 (SV2) and PSD (postsynaptic density)-95, and those that coincided with PNA resided closest to bipolar cell somas. Cone-RBC synaptic contacts were identified by: (a) RBC dendrites deeply invaginating into the center of cone pedicles (invaginating synapses), (b) RBC dendritic spines intruding into the surface of cone pedicles (superficial synapses), and (c) PKCα immunoreactivity coinciding with synaptic marker SV2, PSD-95, mGluR6, G protein beta 5 or PNA at cone pedicles. One RBC could form 0-1 invaginating and 1-3 superficial contacts with cones. 20.7% and 38.9% of mouse RBCs contacted cones in the peripheral and central retina (p < .05, n = 14 samples), respectively, while 34.4% (peripheral) and 48.5% (central) of cones contacted RBCs (p > .05). In baboon retinas (n = 4 samples), cone-RBC contacts involved 12.2% of RBCs (n = 416 cells) and 22.5% of cones (n = 225 cells). This suggests that rod and cone signals in the ON pathway are integrated in some RBCs before reaching AII amacrine cells.
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Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Zhuo Yang
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Roy A Jacoby
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
| | - Samuel M Wu
- Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, 77030
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Shah AK, Kreibich CD, Amdam GV, Münch D. Metabolic enzymes in glial cells of the honeybee brain and their associations with aging, starvation and food response. PLoS One 2018; 13:e0198322. [PMID: 29927967 PMCID: PMC6013123 DOI: 10.1371/journal.pone.0198322] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/17/2018] [Indexed: 12/03/2022] Open
Abstract
The honey bee has been extensively studied as a model for neuronal circuit and memory function and more recently has emerged as an unconventional model in biogerontology. Yet, the detailed knowledge of neuronal processing in the honey bee brain contrasts with the very sparse information available on glial cells. In other systems glial cells are involved in nutritional homeostasis, detoxification, and aging. These glial functions have been linked to metabolic enzymes, such as glutamine synthetase and glycogen phosphorylase. As a step in identifying functional roles and potential differences among honey bee glial types, we examined the spatial distribution of these enzymes and asked if enzyme abundance is associated with aging and other processes essential for survival. Using immunohistochemistry and confocal laser microscopy we demonstrate that glutamine synthetase and glycogen phosphorylase are abundant in glia but appear to co-localize with different glial sub-types. The overall spatial distribution of both enzymes was not homogenous and differed markedly between different neuropiles and also within each neuropil. Using semi-quantitative Western blotting we found that rapid aging, typically observed in shortest-lived worker bees (foragers), was associated with declining enzyme levels. Further, we found enzyme abundance changes after severe starvation stress, and that glutamine synthetase is associated with food response. Together, our data indicate that aging and nutritional physiology in bees are linked to glial specific metabolic enzymes. Enzyme specific localization patterns suggest a functional differentiation among identified glial types.
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Affiliation(s)
- Ashish K. Shah
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
| | - Claus D. Kreibich
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
| | - Gro V. Amdam
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Daniel Münch
- Faculty of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Aas, Norway
- * E-mail:
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Alberini CM, Cruz E, Descalzi G, Bessières B, Gao V. Astrocyte glycogen and lactate: New insights into learning and memory mechanisms. Glia 2018; 66:1244-1262. [PMID: 29076603 PMCID: PMC5903986 DOI: 10.1002/glia.23250] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 09/05/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Memory, the ability to retain learned information, is necessary for survival. Thus far, molecular and cellular investigations of memory formation and storage have mainly focused on neuronal mechanisms. In addition to neurons, however, the brain comprises other types of cells and systems, including glia and vasculature. Accordingly, recent experimental work has begun to ask questions about the roles of non-neuronal cells in memory formation. These studies provide evidence that all types of glial cells (astrocytes, oligodendrocytes, and microglia) make important contributions to the processing of encoded information and storing memories. In this review, we summarize and discuss recent findings on the critical role of astrocytes as providers of energy for the long-lasting neuronal changes that are necessary for long-term memory formation. We focus on three main findings: first, the role of glucose metabolism and the learning- and activity-dependent metabolic coupling between astrocytes and neurons in the service of long-term memory formation; second, the role of astrocytic glucose metabolism in arousal, a state that contributes to the formation of very long-lasting and detailed memories; and finally, in light of the high energy demands of the brain during early development, we will discuss the possible role of astrocytic and neuronal glucose metabolisms in the formation of early-life memories. We conclude by proposing future directions and discussing the implications of these findings for brain health and disease. Astrocyte glycogenolysis and lactate play a critical role in memory formation. Emotionally salient experiences form strong memories by recruiting astrocytic β2 adrenergic receptors and astrocyte-generated lactate. Glycogenolysis and astrocyte-neuron metabolic coupling may also play critical roles in memory formation during development, when the energy requirements of brain metabolism are at their peak.
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Affiliation(s)
- Cristina M Alberini
- Center for Neural Science, New York University, New York, New York, 10003
- Associate Investigator, Neuroscience Institute, NYU Langone Medical Center, New York, New York, 10016
| | - Emmanuel Cruz
- Center for Neural Science, New York University, New York, New York, 10003
| | - Giannina Descalzi
- Center for Neural Science, New York University, New York, New York, 10003
| | - Benjamin Bessières
- Center for Neural Science, New York University, New York, New York, 10003
| | - Virginia Gao
- Center for Neural Science, New York University, New York, New York, 10003
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Bak LK, Walls AB, Schousboe A, Waagepetersen HS. Astrocytic glycogen metabolism in the healthy and diseased brain. J Biol Chem 2018; 293:7108-7116. [PMID: 29572349 DOI: 10.1074/jbc.r117.803239] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The brain contains a fairly low amount of glycogen, mostly located in astrocytes, a fact that has prompted the suggestion that glycogen does not have a significant physiological role in the brain. However, glycogen metabolism in astrocytes is essential for several key physiological processes and is adversely affected in disease. For instance, diminished ability to break down glycogen impinges on learning, and epilepsy, Alzheimer's disease, and type 2 diabetes are all associated with abnormal astrocyte glycogen metabolism. Glycogen metabolism supports astrocytic K+ and neurotransmitter glutamate uptake and subsequent glutamine synthesis-three fundamental steps in excitatory signaling at most brain synapses. Thus, there is abundant evidence for a key role of glycogen in brain function. Here, we summarize the physiological brain functions that depend on glycogen, discuss glycogen metabolism in disease, and investigate how glycogen breakdown is regulated at the cellular and molecular levels.
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Affiliation(s)
- Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Anne B Walls
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen, Denmark
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Carlson GM, Dienel GA, Colbran RJ. Introduction to the Thematic Minireview Series: Brain glycogen metabolism. J Biol Chem 2018. [PMID: 29514979 DOI: 10.1074/jbc.tm118.002642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The synthesis of glycogen allows for efficient intracellular storage of glucose molecules in a soluble form that can be rapidly released to enter glycolysis in response to energy demand. Intensive studies of glucose and glycogen metabolism, predominantly in skeletal muscle and liver, have produced innumerable insights into the mechanisms of hormone action, resulting in the award of several Nobel Prizes over the last one hundred years. Glycogen is actually present in all cells and tissues, albeit at much lower levels than found in muscle or liver. However, metabolic and physiological roles of glycogen in other tissues are poorly understood. This series of Minireviews summarizes what is known about the enzymes involved in brain glycogen metabolism and studies that have linked glycogen metabolism to multiple brain functions involving metabolic communication between astrocytes and neurons. Recent studies unexpectedly linking some forms of epilepsy to mutations in two poorly understood proteins involved in glycogen metabolism are also reviewed.
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Affiliation(s)
- Gerald M Carlson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160.
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72201.
| | - Roger J Colbran
- Department of Molecular Physiology & Biophysics, The Vanderbilt Brain Institute, and The Vanderbilt Kennedy Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615.
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Gentry MS, Guinovart JJ, Minassian BA, Roach PJ, Serratosa JM. Lafora disease offers a unique window into neuronal glycogen metabolism. J Biol Chem 2018; 293:7117-7125. [PMID: 29483193 DOI: 10.1074/jbc.r117.803064] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Lafora disease (LD) is a fatal, autosomal recessive, glycogen-storage disorder that manifests as severe epilepsy. LD results from mutations in the gene encoding either the glycogen phosphatase laforin or the E3 ubiquitin ligase malin. Individuals with LD develop cytoplasmic, aberrant glycogen inclusions in nearly all tissues that more closely resemble plant starch than human glycogen. This Minireview discusses the unique window into glycogen metabolism that LD research offers. It also highlights recent discoveries, including that glycogen contains covalently bound phosphate and that neurons synthesize glycogen and express both glycogen synthase and glycogen phosphorylase.
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Affiliation(s)
- Matthew S Gentry
- Lafora Epilepsy Cure Initiative, Lexington, Kentucky 40503; Department of Biochemistry and Molecular Biology, Lexington, Kentucky 40503; University of Kentucky Epilepsy Research Center (EpiC), University of Kentucky, Lexington, Kentucky 40503.
| | - Joan J Guinovart
- Lafora Epilepsy Cure Initiative, Lexington, Kentucky 40503; Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, 08028 Barcelona, Spain; Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders (CIBERDEM), 28029 Madrid, Spain; Department of Biochemistry and Molecular Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Berge A Minassian
- Lafora Epilepsy Cure Initiative, Lexington, Kentucky 40503; Department of Pediatrics and Dallas Children's Medical Center, University of Texas Southwestern, Dallas, Texas 75390-9063; Department of Pediatrics, The Hospital for Sick Children Research Institute, University of Toronto, Toronto, Ontario M5G 0A4, Canada
| | - Peter J Roach
- Lafora Epilepsy Cure Initiative, Lexington, Kentucky 40503; Department of Biochemistry and Molecular Biology, Center for Diabetes and Metabolic Diseases and Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jose M Serratosa
- Lafora Epilepsy Cure Initiative, Lexington, Kentucky 40503; Laboratory of Neurology, IIS-Jimenez Diaz Foundation, UAM, 28045 Madrid, Spain; Biomedical Research Networking Center on Rare Diseases (CIBERER), 28029 Madrid, Spain
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Abstract
The key regulatory enzymes of glycogenolysis are phosphorylase kinase, a hetero-oligomer with four different types of subunits, and glycogen phosphorylase, a homodimer. Both enzymes are activated by phosphorylation and small ligands, and both enzymes have distinct isoforms that are predominantly expressed in muscle, liver, or brain; however, whole-transcriptome high-throughput sequencing analyses show that in brain both of these enzymes are likely composed of subunit isoforms representing all three tissues. This Minireview examines the regulatory properties of the isoforms of these two enzymes expressed in the three tissues, focusing on their potential regulatory similarities and differences. Additionally, the activity, structure, and regulation of the remaining enzyme necessary for glycogenolysis, glycogen-debranching enzyme, are also reviewed.
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Affiliation(s)
- Owen W Nadeau
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160-7421
| | - Joseph D Fontes
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160-7421
| | - Gerald M Carlson
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160-7421.
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Glycogen metabolism in brain and neurons - astrocytes metabolic cooperation can be altered by pre- and neonatal lead (Pb) exposure. Toxicology 2017; 390:146-158. [PMID: 28916327 DOI: 10.1016/j.tox.2017.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/28/2017] [Accepted: 09/07/2017] [Indexed: 11/22/2022]
Abstract
Lead (Pb) is an environmental neurotoxin which particularly affects the developing brain but the molecular mechanism of its neurotoxicity still needs clarification. The aim of this paper was to examine whether pre- and neonatal exposure to Pb (concentration of Pb in rat offspring blood below the "threshold level") may affect the brain's energy metabolism in neurons and astrocytes via the amount of available glycogen. We investigated the glycogen concentration in the brain, as well as the expression of the key enzymes involved in glycogen metabolism in brain: glycogen synthase 1 (Gys1), glycogen phosphorylase (PYGM, an isoform active in astrocytes; and PYGB, an isoform active in neurons) and phosphorylase kinase β (PHKB). Moreover, the expression of connexin 43 (Cx43) was evaluated to analyze whether Pb poisoning during the early phase of life may affect the neuron-astrocytes' metabolic cooperation. This work shows for the first time that exposure to Pb in early life can impair brain energy metabolism by reducing the amount of glycogen and decreasing the rate of its metabolism. This reduction in brain glycogen level was accompanied by a decrease in Gys1 expression. We noted a reduction in the immunoreactivity and the gene expression of both PYGB and PYGM isoform, as well as an increase in the expression of PHKB in Pb-treated rats. Moreover, exposure to Pb induced decrease in connexin 43 immunoexpression in all the brain structures analyzed, both in astrocytes as well as in neurons. Our data suggests that exposure to Pb in the pre- and neonatal periods results in a decrease in the level of brain glycogen and a reduction in the rate of its metabolism, thereby reducing glucose availability, which as a further consequence may lead to the impairment of brain energy metabolism and the metabolic cooperation between neurons and astrocytes.
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Liu B, Teschemacher AG, Kasparov S. Neuroprotective potential of astroglia. J Neurosci Res 2017; 95:2126-2139. [PMID: 28836687 DOI: 10.1002/jnr.24140] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 07/14/2017] [Accepted: 07/24/2017] [Indexed: 12/13/2022]
Abstract
Astroglia are the homoeostatic cells of the central nervous system, which participate in all essential functions of the brain. Astrocytes support neuronal networks by handling water and ion fluxes, transmitter clearance, provision of antioxidants, and metabolic precursors and growth factors. The critical dependence of neurons on constant support from the astrocytes confers astrocytes with intrinsic neuroprotective properties. On the other hand, loss of astrocytic support or their pathological transformation compromises neuronal functionality and viability. Manipulating neuroprotective functions of astrocytes is thus an important strategy to enhance neuronal survival and improve outcomes in disease states. © 2017 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Beihui Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom
| | - A G Teschemacher
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom
| | - Sergey Kasparov
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom.,Institute of Living Systems, School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russian Federation
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39
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Ashrafi G, Ryan TA. Glucose metabolism in nerve terminals. Curr Opin Neurobiol 2017; 45:156-161. [PMID: 28605677 DOI: 10.1016/j.conb.2017.03.007] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/16/2017] [Indexed: 12/25/2022]
Abstract
Nerve terminals in the brain carry out the primary form of intercellular communication between neurons. Neurotransmission, however, requires adequate supply of ATP to support energetically demanding steps, including the maintenance of ionic gradients, reversing changes in intracellular Ca2+ that arise from opening voltage-gated Ca2+ channels, as well recycling synaptic vesicles. The energy demands of the brain are primarily met by glucose which is oxidized through glycolysis and oxidative phosphorylation to produce ATP. The pathways of ATP production have to respond rapidly to changes in energy demand at the synapse to sustain neuronal activity. In this review, we discuss recent progress in understanding the mechanisms regulating glycolysis at nerve terminals, their contribution to synaptic function, and how dysregulation of glycolysis may contribute to neurodegeneration.
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Affiliation(s)
- Ghazaleh Ashrafi
- Department of Biochemistry, Weill Cornell Medical College, New York, USA
| | - Timothy A Ryan
- Department of Biochemistry, Weill Cornell Medical College, New York, USA.
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40
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Kaczor PT, Mozrzymas JW. Key Metabolic Enzymes Underlying Astrocytic Upregulation of GABAergic Plasticity. Front Cell Neurosci 2017; 11:144. [PMID: 28559800 PMCID: PMC5432623 DOI: 10.3389/fncel.2017.00144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/02/2017] [Indexed: 11/30/2022] Open
Abstract
GABAergic plasticity is recognized as a key mechanism of shaping the activity of the neuronal networks. However, its description is challenging because of numerous neuron-specific mechanisms. In particular, while essential role of glial cells in the excitatory plasticity is well established, their involvement in GABAergic plasticity only starts to emerge. To address this problem, we used two models: neuronal cell culture (NC) and astrocyte-neuronal co-culture (ANCC), where we chemically induced long-term potentiation at inhibitory synapses (iLTP). iLTP could be induced both in NC and ANCC but in ANCC its extent was larger. Importantly, this functional iLTP manifestation was accompanied by an increase in gephyrin puncta size. Furthermore, blocking astrocyte Krebs cycle with fluoroacetate (FA) in ANCC prevented enhancement of both mIPSC amplitude and gephyrin puncta size but this effect was not observed in NC, indicating a key role in neuron-astrocyte cross-talk. Blockade of monocarboxylate transport with α-Cyano-4-hydroxycinnamic acid (4CIN) abolished iLTP both in NC and ANCC and in the latter model prevented also enlargement of gephyrin puncta. Similarly, blockade of glycogen phosphorylase with BAYU6751 prevented enlargement of gephyrin puncta upon iLTP induction. Finally, block of glutamine synthetase with methionine sulfoxide (MSO) nearly abolished mIPSC increase in both NMDA stimulated cell groups but did not prevent enlargement of gephyrin puncta. In conclusion, we provide further evidence that GABAergic plasticity is strongly regulated by astrocytes and the underlying mechanisms involve key metabolic enzymes. Considering the strategic role of GABAergic interneurons, the plasticity described here indicates possible mechanism whereby metabolism regulates the network activity.
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Affiliation(s)
- Przemysław T Kaczor
- Department of Molecular Physiology and Neurobiology, Faculty of Biological Sciences, University of WrocławWrocław, Poland
| | - Jerzy W Mozrzymas
- Department of Molecular Physiology and Neurobiology, Faculty of Biological Sciences, University of WrocławWrocław, Poland.,Laboratory of Neuroscience, Department of Biophysics, Wrocław Medical UniversityWrocław, Poland
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41
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Hirayama-Kurogi M, Takizawa Y, Kunii Y, Matsumoto J, Wada A, Hino M, Akatsu H, Hashizume Y, Yamamoto S, Kondo T, Ito S, Tachikawa M, Niwa SI, Yabe H, Terasaki T, Setou M, Ohtsuki S. Downregulation of GNA13-ERK network in prefrontal cortex of schizophrenia brain identified by combined focused and targeted quantitative proteomics. J Proteomics 2017; 158:31-42. [DOI: 10.1016/j.jprot.2017.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 01/06/2023]
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42
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Mathieu C, Bui LC, Petit E, Haddad I, Agbulut O, Vinh J, Dupret JM, Rodrigues-Lima F. Molecular Mechanisms of Allosteric Inhibition of Brain Glycogen Phosphorylase by Neurotoxic Dithiocarbamate Chemicals. J Biol Chem 2016; 292:1603-1612. [PMID: 27965358 DOI: 10.1074/jbc.m116.766725] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/08/2016] [Indexed: 12/19/2022] Open
Abstract
Dithiocarbamates (DTCs) are important industrial chemicals used extensively as pesticides and in a variety of therapeutic applications. However, they have also been associated with neurotoxic effects and in particular with the development of Parkinson-like neuropathy. Although different pathways and enzymes (such as ubiquitin ligases or the proteasome) have been identified as potential targets of DTCs in the brain, the molecular mechanisms underlying their neurotoxicity remain poorly understood. There is increasing evidence that alteration of glycogen metabolism in the brain contributes to neurodegenerative processes. Interestingly, recent studies with N,N-diethyldithiocarbamate suggest that brain glycogen phosphorylase (bGP) and glycogen metabolism could be altered by DTCs. Here, we provide molecular and mechanistic evidence that bGP is a target of DTCs. To examine this system, we first tested thiram, a DTC pesticide known to display neurotoxic effects, observing that it can react rapidly with bGP and readily inhibits its glycogenolytic activity (kinact = 1.4 × 105 m-1 s-1). Using cysteine chemical labeling, mass spectrometry, and site-directed mutagenesis approaches, we show that thiram (and certain of its metabolites) alters the activity of bGP through the formation of an intramolecular disulfide bond (Cys318-Cys326), known to act as a redox switch that precludes the allosteric activation of bGP by AMP. Given the key role of glycogen metabolism in brain functions and neurodegeneration, impairment of the glycogenolytic activity of bGP by DTCs such as thiram may be a new mechanism by which certain DTCs exert their neurotoxic effects.
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Affiliation(s)
- Cécile Mathieu
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Linh-Chi Bui
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Emile Petit
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Iman Haddad
- ESPCI ParisTech, Université Paris Sciences et Lettres, Laboratoire de Spectrométrie de Masse Biologique et Protéomique, CNRS USR, 3149 Paris, France
| | - Onnik Agbulut
- the Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, UMR CNRS 8256, Biological Adaptation and Ageing, 75005 Paris, France
| | - Joelle Vinh
- ESPCI ParisTech, Université Paris Sciences et Lettres, Laboratoire de Spectrométrie de Masse Biologique et Protéomique, CNRS USR, 3149 Paris, France
| | - Jean-Marie Dupret
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France; UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France
| | - Fernando Rodrigues-Lima
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France; UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France.
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43
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Mathieu C, Dupret JM, Rodrigues Lima F. The structure of brain glycogen phosphorylase-from allosteric regulation mechanisms to clinical perspectives. FEBS J 2016; 284:546-554. [PMID: 27782369 DOI: 10.1111/febs.13937] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 10/13/2016] [Accepted: 10/24/2016] [Indexed: 01/15/2023]
Abstract
Glycogen phosphorylase (GP) is the key enzyme that regulates glycogen mobilization in cells. GP is a complex allosteric enzyme that comprises a family of three isozymes: muscle GP (mGP), liver GP (lGP), and brain GP (bGP). Although the three isozymes display high similarity and catalyze the same reaction, they differ in their sensitivity to the allosteric activator adenosine monophosphate (AMP). Moreover, inactivating mutations in mGP and lGP have been known to be associated with glycogen storage diseases (McArdle and Hers disease, respectively). The determination, decades ago, of the structure of mGP and lGP have allowed to better understand the allosteric regulation of these two isoforms and the development of specific inhibitors. Despite its important role in brain glycogen metabolism, the structure of the brain GP had remained elusive. Here, we provide an overview of the human brain GP structure and its relationship with the two other members of this key family of the metabolic enzymes. We also summarize how this structure provides valuable information to understand the regulation of bGP and to design specific ligands of potential pharmacological interest.
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Affiliation(s)
- Cécile Mathieu
- Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, Université Paris Diderot, France
| | - Jean-Marie Dupret
- Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, Université Paris Diderot, France.,UFR Sciences du Vivant, Université Paris Diderot, France
| | - Fernando Rodrigues Lima
- Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, Université Paris Diderot, France.,UFR Sciences du Vivant, Université Paris Diderot, France
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44
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Pinacho R, Vila E, Prades R, Tarragó T, Castro E, Ferrer I, Ramos B. The glial phosphorylase of glycogen isoform is reduced in the dorsolateral prefrontal cortex in chronic schizophrenia. Schizophr Res 2016; 177:37-43. [PMID: 27156240 DOI: 10.1016/j.schres.2016.04.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/10/2016] [Accepted: 04/13/2016] [Indexed: 12/13/2022]
Abstract
Reduced glutamatergic activity and energy metabolism in the dorsolateral prefrontal cortex (DLPFC) have been described in schizophrenia. Glycogenolysis in astrocytes is responsible for providing neurons with lactate as a transient energy supply helping to couple glutamatergic neurotransmission and glucose utilization in the brain. This mechanism could be disrupted in schizophrenia. The aim of this study was to explore whether the protein levels of the astrocyte isoform of glycogen phosphorylase (PYGM), key enzyme of glycogenolysis, and the isoform A of Ras-related C3 botulinum toxin substrate 1 (RAC1), a kinase that regulates PYGM activity, are altered in the postmortem DLPFC of chronic schizophrenia patients (n=23) and matched controls (n=23). We also aimed to test NMDAR blockade effect on these proteins in the mouse cortex and cortical astrocytes and antipsychotic treatments in rats. Here we report a reduction in PYGM and RAC1 protein levels in the DLPFC in schizophrenia. We found that treatment with the NMDAR antagonist dizocilpine in mice as a model of psychosis increased PYGM and reduced RAC1 protein levels. The same result was observed in rat cortical astroglial-enriched cultures. 21-day haloperidol treatment increased PYGM levels in rats. These results show that PYGM and RAC1 are altered in the DLPFC in chronic schizophrenia and are controlled by NMDA signalling in the rodent cortex and cortical astrocytes suggesting an altered NMDA-dependent glycogenolysis in astrocytes in schizophrenia. Together, this study provides evidence of a NMDA-dependent transient local energy deficit in neuron-glia crosstalk in schizophrenia, contributing to energy deficits of the disorder.
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Affiliation(s)
- Raquel Pinacho
- Unitat de recerca, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Universitat de Barcelona, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM. Dr. Antoni Pujadas, 42, 08830, Sant Boi de Llobregat, Barcelona, Spain
| | - Elia Vila
- Unitat de recerca, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Universitat de Barcelona, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM. Dr. Antoni Pujadas, 42, 08830, Sant Boi de Llobregat, Barcelona, Spain
| | - Roger Prades
- Iproteos S.L., Baldiri I Reixac, 10, 08028 Barcelona, Spain
| | - Teresa Tarragó
- Iproteos S.L., Baldiri I Reixac, 10, 08028 Barcelona, Spain; Institute for Research in Biomedicine (IRB Barcelona), Baldiri I Reixac, 10, 08028 Barcelona, Spain
| | - Elena Castro
- Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC (Universidad de Cantabria, CSIC, SODERCAN), Departamento de Fisiología y Farmacología, Universidad de Cantabria, 39011, Santander, Spain, Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Spain
| | - Isidre Ferrer
- Instituto de Neuropatología, IDIBELL-Hospital Universitari de Bellvitge, Universitat de Barcelona, Centro de Investigación Biomédica en Red para enfermedades neurodegenerativas, CIBERNED, Feixa Llarga s/n, 08907 Hospitalet de LLobregat, Barcelona, Spain
| | - Belén Ramos
- Unitat de recerca, Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Universitat de Barcelona, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM. Dr. Antoni Pujadas, 42, 08830, Sant Boi de Llobregat, Barcelona, Spain.
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45
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Mathieu C, Duval R, Cocaign A, Petit E, Bui LC, Haddad I, Vinh J, Etchebest C, Dupret JM, Rodrigues-Lima F. An Isozyme-specific Redox Switch in Human Brain Glycogen Phosphorylase Modulates Its Allosteric Activation by AMP. J Biol Chem 2016; 291:23842-23853. [PMID: 27660393 DOI: 10.1074/jbc.m116.757062] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 09/21/2016] [Indexed: 12/22/2022] Open
Abstract
Brain glycogen and its metabolism are increasingly recognized as major players in brain functions. Moreover, alteration of glycogen metabolism in the brain contributes to neurodegenerative processes. In the brain, both muscle and brain glycogen phosphorylase isozymes regulate glycogen mobilization. However, given their distinct regulatory features, these two isozymes could confer distinct metabolic functions of glycogen in brain. Interestingly, recent proteomics studies have identified isozyme-specific reactive cysteine residues in brain glycogen phosphorylase (bGP). In this study, we show that the activity of human bGP is redox-regulated through the formation of a disulfide bond involving a highly reactive cysteine unique to the bGP isozyme. We found that this disulfide bond acts as a redox switch that precludes the allosteric activation of the enzyme by AMP without affecting its activation by phosphorylation. This unique regulatory feature of bGP sheds new light on the isoform-specific regulation of glycogen phosphorylase and glycogen metabolism.
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Affiliation(s)
- Cécile Mathieu
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris
| | - Romain Duval
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris
| | - Angélique Cocaign
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris
| | - Emile Petit
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris
| | - Linh-Chi Bui
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris
| | - Iman Haddad
- ESPCI Paris, PSL Research University, Spectrométrie de Masse Biologique et Protéomique (SMPB), CNRS USR 3149, 10 rue Vauquelin, F75231 Paris cedex 05, France
| | - Joelle Vinh
- ESPCI Paris, PSL Research University, Spectrométrie de Masse Biologique et Protéomique (SMPB), CNRS USR 3149, 10 rue Vauquelin, F75231 Paris cedex 05, France
| | - Catherine Etchebest
- INSERM, UMR S1134, Université Paris Diderot, F-75015 Paris.,Université Paris Diderot, Sorbonne Paris Cité, F-75013 Paris.,Institut National de la Transfusion Sanguine (INTS), 75015 Paris.,GR-Ex, Laboratoire d'excellence, 75015 Paris, and.,UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France
| | - Jean-Marie Dupret
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris.,UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France
| | - Fernando Rodrigues-Lima
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, .,UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France
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46
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Kulkarni M, Trifunović D, Schubert T, Euler T, Paquet-Durand F. Calcium dynamics change in degenerating cone photoreceptors. Hum Mol Genet 2016; 25:3729-3740. [PMID: 27402880 DOI: 10.1093/hmg/ddw219] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/24/2016] [Accepted: 06/25/2016] [Indexed: 11/14/2022] Open
Abstract
Cone photoreceptors (cones) are essential for high-resolution daylight vision and colour perception. Loss of cones in hereditary retinal diseases has a dramatic impact on human vision. The mechanisms underlying cone death are poorly understood, and consequently, there are no treatments available. Previous studies suggest a central role for calcium (Ca2+) homeostasis deficits in photoreceptor degeneration; however, direct evidence for this is scarce and physiological measurements of Ca2+ in degenerating mammalian cones are lacking.Here, we took advantage of the transgenic HR2.1:TN-XL mouse line that expresses a genetically encoded Ca2+ biosensor exclusively in cones. We cross-bred this line with mouse models for primary ("cone photoreceptor function loss-1", cpfl1) and secondary ("retinal degeneration-1", rd1) cone degeneration, respectively, and assessed resting Ca2+ levels and light-evoked Ca2+ responses in cones using two-photon imaging. We found that Ca2+ dynamics were altered in cpfl1 cones, showing higher noise and variable Ca2+ levels, with significantly wider distribution than for wild-type and rd1 cones. Unexpectedly, up to 21% of cpfl1 cones still displayed light-evoked Ca2+ responses, which were larger and slower than wild-type responses. In contrast, genetically intact rd1 cones were characterized by lower noise and complete lack of visual function.Our study demonstrates alterations in cone Ca2+ dynamics in both primary and secondary cone degeneration. Our results are consistent with the view that higher (fluctuating) cone Ca2+ levels are involved in photoreceptor cell death in primary (cpfl1) but not in secondary (rd1) cone degeneration. These findings may guide the future development of therapies targeting photoreceptor Ca2+ homeostasis.
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Affiliation(s)
- Manoj Kulkarni
- Institute for Ophthalmic Research.,Werner Reichardt Centre for Integrative Neuroscience.,Graduate School of Cellular & Molecular Neuroscience
| | | | - Timm Schubert
- Institute for Ophthalmic Research.,Werner Reichardt Centre for Integrative Neuroscience
| | - Thomas Euler
- Institute for Ophthalmic Research (F.P-D.) (T.E.).,Werner Reichardt Centre for Integrative Neuroscience.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
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47
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Mathieu C, Li de la Sierra-Gallay I, Duval R, Xu X, Cocaign A, Léger T, Woffendin G, Camadro JM, Etchebest C, Haouz A, Dupret JM, Rodrigues-Lima F. Insights into Brain Glycogen Metabolism: THE STRUCTURE OF HUMAN BRAIN GLYCOGEN PHOSPHORYLASE. J Biol Chem 2016; 291:18072-83. [PMID: 27402852 DOI: 10.1074/jbc.m116.738898] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Indexed: 11/06/2022] Open
Abstract
Brain glycogen metabolism plays a critical role in major brain functions such as learning or memory consolidation. However, alteration of glycogen metabolism and glycogen accumulation in the brain contributes to neurodegeneration as observed in Lafora disease. Glycogen phosphorylase (GP), a key enzyme in glycogen metabolism, catalyzes the rate-limiting step of glycogen mobilization. Moreover, the allosteric regulation of the three GP isozymes (muscle, liver, and brain) by metabolites and phosphorylation, in response to hormonal signaling, fine-tunes glycogenolysis to fulfill energetic and metabolic requirements. Whereas the structures of muscle and liver GPs have been known for decades, the structure of brain GP (bGP) has remained elusive despite its critical role in brain glycogen metabolism. Here, we report the crystal structure of human bGP in complex with PEG 400 (2.5 Å) and in complex with its allosteric activator AMP (3.4 Å). These structures demonstrate that bGP has a closer structural relationship with muscle GP, which is also activated by AMP, contrary to liver GP, which is not. Importantly, despite the structural similarities between human bGP and the two other mammalian isozymes, the bGP structures reveal molecular features unique to the brain isozyme that provide a deeper understanding of the differences in the activation properties of these allosteric enzymes by the allosteric effector AMP. Overall, our study further supports that the distinct structural and regulatory properties of GP isozymes contribute to the different functions of muscle, liver, and brain glycogen.
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Affiliation(s)
- Cécile Mathieu
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Ines Li de la Sierra-Gallay
- the Fonction et Architecture des Assemblages Macromoléculaires, Institut de Biologie Intégrative de la Cellule, Université Paris Sud, UMR 9198 Orsay, 91405 France
| | - Romain Duval
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Ximing Xu
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Angélique Cocaign
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France
| | - Thibaut Léger
- the Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, 75013 Paris, France
| | - Gary Woffendin
- Thermo Fisher Scientific, Hemel Hempstead HP2 7GE, United Kingdom
| | - Jean-Michel Camadro
- the Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, CNRS UMR 7592, 75013 Paris, France
| | - Catherine Etchebest
- INSERM, UMR S1134, Université Paris Diderot, 75015 Paris, France, Université Paris Diderot, Sorbonne Paris Cité, 75004 Paris, France, Institut National de la Transfusion Sanguine, 75015 Paris, France, Laboratoire d'Excellence GR-Ex, 75015 Paris, France, UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France, and
| | - Ahmed Haouz
- the Institut Pasteur, Plateforme de Cristallographie, CNRS UMR 3528, 75015 Paris, France
| | - Jean-Marie Dupret
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France, UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France, and
| | - Fernando Rodrigues-Lima
- From the Université Paris Diderot, Sorbonne Paris Cité, Unité BFA, CNRS UMR 8251, 75013 Paris, France, UFR Sciences du Vivant, Université Paris Diderot, 75013 Paris, France, and
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48
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Park HJ, Chang Y, Lee JE, Koo H, Oh J, Choi YC, Park KD. Recurrent Episodes of Rhabdomyolysis after Seizures in a Patient with Glycogen Storage Disease Type V. J Clin Neurol 2016; 12:373-5. [PMID: 27273923 PMCID: PMC4960225 DOI: 10.3988/jcn.2016.12.3.373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 11/17/2022] Open
Affiliation(s)
- Hyung Jun Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Yoonkyung Chang
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Jee Eun Lee
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Heasoo Koo
- Department of Pathology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Jeeyoung Oh
- Department of Neurology, Konkuk University School of Medicine, Seoul, Korea
| | - Young Chul Choi
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
| | - Kee Duk Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea.
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49
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Zhang Y, Xue Y, Meng S, Luo Y, Liang J, Li J, Ai S, Sun C, Shen H, Zhu W, Wu P, Lu L, Shi J. Inhibition of Lactate Transport Erases Drug Memory and Prevents Drug Relapse. Biol Psychiatry 2016; 79:928-39. [PMID: 26293178 DOI: 10.1016/j.biopsych.2015.07.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/23/2015] [Accepted: 07/10/2015] [Indexed: 12/31/2022]
Abstract
BACKGROUND Drug memories that associate drug-paired stimuli with the effects of abused drugs contribute to relapse. Exposure to drug-associated contexts causes consolidated drug memories to be in a labile state, during which manipulations can be given to impair drug memories. Although substantial evidence demonstrates the crucial role of neuronal signaling in addiction, little is known about the contribution of astrocyte-neuron communication. METHODS Rats were trained for cocaine-induced conditioned place preference (CPP) or self-administration and microinjected with the glycogen phosphorylation inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol into the basolateral amygdala (BLA) immediately after retrieval. The concentration of lactate was measured immediately after retrieval via microdialysis, and the CPP score and number of nosepokes were recorded 24 hours later. Furthermore, we used antisense oligodeoxynucleotides to disrupt the expression of astrocytic lactate transporters (monocarboxylate transporters 1 and 2) in the BLA after retrieval, tested the expression of CPP 1 day later, and injected L-lactate into the BLA 15 minutes before retrieval to rescue the effects of the oligodeoxynucleotides. RESULTS Injection of 1,4-dideoxy-1,4-imino-D-arabinitol into the BLA immediately after retrieval prevented the subsequent expression of cocaine-induced CPP, decreased the concentration of lactate in the BLA, and reduced the number of nosepokes for cocaine self-administration. Disrupting the expression of monocarboxylate transporters 1 and 2 in the BLA also caused subsequent deficits in the expression of cocaine-induced CPP, which was rescued by pretreatment with L-lactate. CONCLUSIONS Our results suggest that astrocyte-neuron lactate transport in the BLA is critical for the reconsolidation of cocaine memory.
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Affiliation(s)
- Yan Zhang
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Yanxue Xue
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Shiqiu Meng
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Yixiao Luo
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Jie Liang
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Jiali Li
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Sizhi Ai
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Chengyu Sun
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Haowei Shen
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Weili Zhu
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Ping Wu
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China
| | - Lin Lu
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China; Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Beijing, China; Peking-Tsinghua Center for Life Sciences and Peking University-International Data Group/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - Jie Shi
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Beijing, China.
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Astroglial glutamate transporters coordinate excitatory signaling and brain energetics. Neurochem Int 2016; 98:56-71. [PMID: 27013346 DOI: 10.1016/j.neuint.2016.03.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 12/22/2022]
Abstract
In the mammalian brain, a family of sodium-dependent transporters maintains low extracellular glutamate and shapes excitatory signaling. The bulk of this activity is mediated by the astroglial glutamate transporters GLT-1 and GLAST (also called EAAT2 and EAAT1). In this review, we will discuss evidence that these transporters co-localize with, form physical (co-immunoprecipitable) interactions with, and functionally couple to various 'energy-generating' systems, including the Na(+)/K(+)-ATPase, the Na(+)/Ca(2+) exchanger, glycogen metabolizing enzymes, glycolytic enzymes, and mitochondria/mitochondrial proteins. This functional coupling is bi-directional with many of these systems both being regulated by glutamate transport and providing the 'fuel' to support glutamate uptake. Given the importance of glutamate uptake to maintaining synaptic signaling and preventing excitotoxicity, it should not be surprising that some of these systems appear to 'redundantly' support the energetic costs of glutamate uptake. Although the glutamate-glutamine cycle contributes to recycling of neurotransmitter pools of glutamate, this is an over-simplification. The ramifications of co-compartmentalization of glutamate transporters with mitochondria for glutamate metabolism are discussed. Energy consumption in the brain accounts for ∼20% of the basal metabolic rate and relies almost exclusively on glucose for the production of ATP. However, the brain does not possess substantial reserves of glucose or other fuels. To ensure adequate energetic supply, increases in neuronal activity are matched by increases in cerebral blood flow via a process known as 'neurovascular coupling'. While the mechanisms for this coupling are not completely resolved, it is generally agreed that astrocytes, with processes that extend to synapses and endfeet that surround blood vessels, mediate at least some of the signal that causes vasodilation. Several studies have shown that either genetic deletion or pharmacologic inhibition of glutamate transport impairs neurovascular coupling. Together these studies strongly suggest that glutamate transport not only coordinates excitatory signaling, but also plays a pivotal role in regulating brain energetics.
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