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Hushmandi K, Einollahi B, Saadat SH, Lee EHC, Farani MR, Okina E, Huh YS, Nabavi N, Salimimoghadam S, Kumar AP. Amino acid transporters within the solute carrier superfamily: Underappreciated proteins and novel opportunities for cancer therapy. Mol Metab 2024; 84:101952. [PMID: 38705513 PMCID: PMC11112377 DOI: 10.1016/j.molmet.2024.101952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/24/2024] [Accepted: 04/27/2024] [Indexed: 05/07/2024] Open
Abstract
BACKGROUND Solute carrier (SLC) transporters, a diverse family of membrane proteins, are instrumental in orchestrating the intake and efflux of nutrients including amino acids, vitamins, ions, nutrients, etc, across cell membranes. This dynamic process is critical for sustaining the metabolic demands of cancer cells, promoting their survival, proliferation, and adaptation to the tumor microenvironment (TME). Amino acids are fundamental building blocks of cells and play essential roles in protein synthesis, nutrient sensing, and oncogenic signaling pathways. As key transporters of amino acids, SLCs have emerged as crucial players in maintaining cellular amino acid homeostasis, and their dysregulation is implicated in various cancer types. Thus, understanding the intricate connections between amino acids, SLCs, and cancer is pivotal for unraveling novel therapeutic targets and strategies. SCOPE OF REVIEW In this review, we delve into the significant impact of amino acid carriers of the SLCs family on the growth and progression of cancer and explore the current state of knowledge in this field, shedding light on the molecular mechanisms that underlie these relationships and highlighting potential avenues for future research and clinical interventions. MAJOR CONCLUSIONS Amino acids transportation by SLCs plays a critical role in tumor progression. However, some studies revealed the tumor suppressor function of SLCs. Although several studies evaluated the function of SLC7A11 and SLC1A5, the role of some SLC proteins in cancer is not studied well. To exert their functions, SLCs mediate metabolic rewiring, regulate the maintenance of redox balance, affect main oncogenic pathways, regulate amino acids bioavailability within the TME, and alter the sensitivity of cancer cells to therapeutics. However, different therapeutic methods that prevent the function of SLCs were able to inhibit tumor progression. This comprehensive review provides insights into a rapidly evolving area of cancer biology by focusing on amino acids and their transporters within the SLC superfamily.
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Affiliation(s)
- Kiavash Hushmandi
- Nephrology and Urology Research Center, Clinical Sciences Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
| | - Behzad Einollahi
- Nephrology and Urology Research Center, Clinical Sciences Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Seyed Hassan Saadat
- Nephrology and Urology Research Center, Clinical Sciences Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - E Hui Clarissa Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Marzieh Ramezani Farani
- NanoBio High-Tech Materials Research Center, Department of Biological Sciences and Bioengineering, Inha University, Incheon 22212, Republic of Korea
| | - Elena Okina
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yun Suk Huh
- NanoBio High-Tech Materials Research Center, Department of Biological Sciences and Bioengineering, Inha University, Incheon 22212, Republic of Korea
| | - Noushin Nabavi
- Department of Urologic Sciences and Vancouver Prostate Centre, University of British Columbia, V6H3Z6, Vancouver, BC, Canada
| | - Shokooh Salimimoghadam
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
| | - Alan Prem Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Fontana IC, Souza DG, Souza DO, Gee A, Zimmer ER, Bongarzone S. A Medicinal Chemistry Perspective on Excitatory Amino Acid Transporter 2 Dysfunction in Neurodegenerative Diseases. J Med Chem 2023; 66:2330-2346. [PMID: 36787643 PMCID: PMC9969404 DOI: 10.1021/acs.jmedchem.2c01572] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The excitatory amino acid transporter 2 (EAAT2) plays a key role in the clearance and recycling of glutamate - the major excitatory neurotransmitter in the mammalian brain. EAAT2 loss/dysfunction triggers a cascade of neurodegenerative events, comprising glutamatergic excitotoxicity and neuronal death. Nevertheless, our current knowledge regarding EAAT2 in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD), is restricted to post-mortem analysis of brain tissue and experimental models. Thus, detecting EAAT2 in the living human brain might be crucial to improve diagnosis/therapy for ALS and AD. This perspective article describes the role of EAAT2 in physio/pathological processes and provides a structure-activity relationship of EAAT2-binders, bringing two perspectives: therapy (activators) and diagnosis (molecular imaging tools).
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Affiliation(s)
- Igor C Fontana
- School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom.,Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90035-003 Porto Alegre, Brazil.,Division of Clinical Geriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Blickagången 16 - Neo floor seventh, 141 83 Stockholm, Sweden
| | - Débora G Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90035-003 Porto Alegre, Brazil.,Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 Porto Alegre, Brazil
| | - Diogo O Souza
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90035-003 Porto Alegre, Brazil.,Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90035-003 Porto Alegre, Brazil
| | - Antony Gee
- School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
| | - Eduardo R Zimmer
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90035-003 Porto Alegre, Brazil.,Department of Pharmacology, Universidade Federal do Rio Grande do Sul, Av. Sarmento Leite 500, sala, 90035-003 Porto Alegre, Brazil.,Graduate Program in Biological Sciences: Biochemistry (PPGBioq), and Pharmacology and Therapeutics (PPGFT), Universidade Federal do Rio Grande do Sul, Av. Sarmento Leite 500, sala, 305 Porto Alegre, Brazil.,Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 Porto Alegre, Brazil.,McGill University Research Centre for Studies in Aging, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Salvatore Bongarzone
- School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, King's College London, London SE1 7EH, United Kingdom
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Gale JR, Kosobucki GJ, Hartnett-Scott KA, Aizenman E. Imprecision in Precision Medicine: Differential Response of a Disease-Linked GluN2A Mutant to NMDA Channel Blockers. Front Pharmacol 2021; 12:773455. [PMID: 34776984 PMCID: PMC8581401 DOI: 10.3389/fphar.2021.773455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in N-methyl-d-aspartate receptors (NMDAR) subunits have been implicated in a growing number of human neurodevelopmental disorders. Previously, a de novo mutation in GRIN2A, encoding the GluN2A subunit, was identified in a patient with severe epilepsy and developmental delay. This missense mutation, which leads to GluN2A-P552R, produces significant dendrotoxicity in transfected rodent cortical neurons, as evidenced by pronounced dendritic blebbing. This injurious process can be prevented by treatment with the NMDA antagonist memantine. Given the increasing use of FDA approved NMDA antagonists to treat patients with GRIN mutations, who may have seizures refractory to traditional anti-epileptic drugs, we investigated whether additional NMDA antagonists were effective in attenuating neurotoxicity associated with GluN2A-P552R expression. Intriguingly, we found that while treatment with memantine can effectively block GluN2A-P552R-mediated dendrotoxicity, treatment with ketamine does not, despite the fact that both drugs work as open NMDAR channel blockers. Interestingly, we found that neurons expressing GluN2A-P552R were more vulnerable to an excitotoxic insult-an effect that, in this case, could be equally rescued by both memantine and ketamine. These findings suggest that GluN2A-P552R induced dendrotoxicity and increased vulnerability to excitotoxic stress are mediated through two distinct mechanisms. The differences between memantine and ketamine in halting GluN2A-P552R dendrotoxicity could not be explained by NMDA antagonist induced changes in MAP or Src kinase activation, previously shown to participate in NMDA-induced excitotoxicity. Our findings strongly suggest that not all NMDA antagonists may be of equal clinical utility in treating GRIN2A-mediated neurological disorders, despite a shared mechanism of action.
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Affiliation(s)
- Jenna R Gale
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Gabrielle J Kosobucki
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Karen A Hartnett-Scott
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Elias Aizenman
- Department of Neurobiology and Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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Goshi N, Morgan RK, Lein PJ, Seker E. A primary neural cell culture model to study neuron, astrocyte, and microglia interactions in neuroinflammation. J Neuroinflammation 2020; 17:155. [PMID: 32393376 PMCID: PMC7216677 DOI: 10.1186/s12974-020-01819-z] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Background Interactions between neurons, astrocytes, and microglia critically influence neuroinflammatory responses to insult in the central nervous system. In vitro astrocyte and microglia cultures are powerful tools to study specific molecular pathways involved in neuroinflammation; however, in order to better understand the influence of cellular crosstalk on neuroinflammation, new multicellular culture models are required. Methods Primary cortical cells taken from neonatal rats were cultured in a serum-free “tri-culture” medium formulated to support neurons, astrocytes, and microglia, or a “co-culture” medium formulated to support only neurons and astrocytes. Caspase 3/7 activity and morphological changes were used to quantify the response of the two culture types to different neuroinflammatory stimuli mimicking sterile bacterial infection (lipopolysaccharide (LPS) exposure), mechanical injury (scratch), and seizure activity (glutamate-induced excitotoxicity). The secreted cytokine profile of control and LPS-exposed co- and tri-cultures were also compared. Results The tri-culture maintained a physiologically relevant representation of neurons, astrocytes, and microglia for 14 days in vitro, while the co-cultures maintained a similar population of neurons and astrocytes, but lacked microglia. The continuous presence of microglia did not negatively impact the overall health of the neurons in the tri-culture, which showed reduced caspase 3/7 activity and similar neurite outgrowth as the co-cultures, along with an increase in the microglia-secreted neurotrophic factor IGF-1 and a significantly reduced concentration of CX3CL1 in the conditioned media. LPS-exposed tri-cultures showed significant astrocyte hypertrophy, increase in caspase 3/7 activity, and the secretion of a number of pro-inflammatory cytokines (e.g., TNF, IL-1α, IL-1β, and IL-6), none of which were observed in LPS-exposed co-cultures. Following mechanical trauma, the tri-culture showed increased caspase 3/7 activity, as compared to the co-culture, along with increased astrocyte migration towards the source of injury. Finally, the microglia in the tri-culture played a significant neuroprotective role during glutamate-induced excitotoxicity, with significantly reduced neuron loss and astrocyte hypertrophy in the tri-culture. Conclusions The tri-culture consisting of neurons, astrocytes, and microglia more faithfully mimics in vivo neuroinflammatory responses than standard mono- and co-cultures. This tri-culture can be a useful tool to study neuroinflammation in vitro with improved accuracy in predicting in vivo neuroinflammatory phenomena.
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Affiliation(s)
- Noah Goshi
- Department of Biomedical Engineering, University of California - Davis, Davis, CA, 95616, USA
| | - Rhianna K Morgan
- Department of Molecular Biosciences, University of California - Davis, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California - Davis, Davis, CA, 95616, USA
| | - Erkin Seker
- Department of Electrical and Computer Engineering, University of California - Davis, 3177 Kemper Hall, Davis, CA, 95616, USA.
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The Relationship Between Glutamate Dynamics and Activity-Dependent Synaptic Plasticity. J Neurosci 2020; 40:2793-2807. [PMID: 32102922 DOI: 10.1523/jneurosci.1655-19.2020] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 02/05/2020] [Accepted: 02/13/2020] [Indexed: 12/22/2022] Open
Abstract
The spatiotemporal dynamics of excitatory neurotransmission must be tightly regulated to achieve efficient synaptic communication. By limiting spillover, glutamate transporters are believed to prevent excessive activation of extrasynaptically located receptors that can impair synaptic plasticity. While glutamate transporter expression is reduced in numerous neurodegenerative diseases, the contributions of transporter dysfunction to disease pathophysiology remain ambiguous as the fundamental relationship between glutamate dynamics and plasticity, and the mechanisms linking these two phenomena, remain poorly understood. Here, we combined electrophysiology and real-time high-speed imaging of extracellular glutamate transients during LTP induction and characterized the sensitivity of the relationship between glutamate dynamics during theta burst stimulation (TBS) and the resulting magnitude of LTP consolidation, both in control conditions and following selective and nonselective glutamate transporter blockade. Glutamate clearance times were negatively correlated with LTP magnitude following nonselective glutamate transporter inhibition but not following selective blockade of a majority of GLT-1, the brain's most abundant glutamate transporter. Although glutamate transporter inhibition reduced the postsynaptic population response to TBS, calcium responses to TBS were greatly exaggerated. The source of excess calcium was dependent on NMDARs, L-type VGCCs, GluA2-lacking AMPARs, and internal calcium stores. Surprisingly, inhibition of L-type VGCCs, but not GluA2-lacking AMPARs or ryanodine receptors, was required to restore robust LTP. In all, these data provide a detailed understanding of the relationship between glutamate dynamics and plasticity and uncover important mechanisms by which poor glutamate uptake can negatively impact LTP consolidation.SIGNIFICANCE STATEMENT Specific patterns of neural activity can promote long-term changes in the strength of synaptic connections through a phenomenon known as synaptic plasticity. Synaptic plasticity is well accepted to represent the cellular mechanisms underlying learning and memory, and many forms of plasticity are initiated by the excitatory neurotransmitter glutamate. While essential for rapid cellular communication in the brain, excessive levels of extracellular glutamate can negatively impact brain function. In this study, we demonstrate that pharmacological manipulations that increase the availability of extracellular glutamate during neural activity can have profoundly negative consequences on synaptic plasticity. We identify mechanisms through which excess glutamate can negatively influence synaptic plasticity, and we discuss the relevance of these findings to neurodegenerative diseases and in the aging brain.
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Trujillo-Chacón LM, Alarcón-Enos JE, Céspedes-Acuña CL, Bustamante L, Baeza M, López MG, Fernández-Mendívil C, Cabezas F, Pastene-Navarrete ER. Neuroprotective activity of isoquinoline alkaloids from of Chilean Amaryllidaceae plants against oxidative stress-induced cytotoxicity on human neuroblastoma SH-SY5Y cells and mouse hippocampal slice culture. Food Chem Toxicol 2019; 132:110665. [DOI: 10.1016/j.fct.2019.110665] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/13/2022]
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Dal-Cim T, Poluceno GG, Lanznaster D, de Oliveira KA, Nedel CB, Tasca CI. Guanosine prevents oxidative damage and glutamate uptake impairment induced by oxygen/glucose deprivation in cortical astrocyte cultures: involvement of A 1 and A 2A adenosine receptors and PI3K, MEK, and PKC pathways. Purinergic Signal 2019; 15:465-476. [PMID: 31520282 DOI: 10.1007/s11302-019-09679-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 08/22/2019] [Indexed: 12/31/2022] Open
Abstract
Glial cells are involved in multiple cerebral functions that profoundly influence brain tissue viability during ischemia, and astrocytes are the main source of extracellular purines as adenosine and guanosine. The endogenous guanine-based nucleoside guanosine is a neuromodulator implicated in important processes in the brain, such as modulation of glutamatergic transmission and protection against oxidative and inflammatory damage. We evaluated if the neuroprotective effect of guanosine is also observed in cultured cortical astrocytes subjected to oxygen/glucose deprivation (OGD) and reoxygenation. We also assessed the involvement of A1 and A2A adenosine receptors and phosphatidylinositol-3 kinase (PI3K), MAPK, and protein kinase C (PKC) signaling pathways on the guanosine effects. OGD/reoxygenation decreased cell viability and glutamate uptake and increased reactive oxygen species (ROS) production in cultured astrocytes. Guanosine treatment prevented these OGD-induced damaging effects. Dipropyl-cyclopentyl-xanthine (an adenosine A1 receptor antagonist) and 4-[2-[[6-amino-9-(N-ethyl-β-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl] benzenepropanoic acid hydrochloride (an adenosine A2A receptor agonist) abolished guanosine-induced protective effects on ROS production, glutamate uptake, and cell viability. The PI3K pathway inhibitor 2-morpholin-4-yl-8-phenylchromen-4-one, the extracellular-signal regulated kinase kinase (MEK) inhibitor 2'-amino-3'-methoxyflavone, or the PKC inhibitor chelerythrine abolished the guanosine effect of preventing OGD-induced cells viability reduction. PI3K inhibition partially prevented the guanosine effect of reducing ROS production, whereas MEK and PKC inhibitions prevented the guanosine effect of restoring glutamate uptake. The total immunocontent of the main astrocytic glutamate transporter glutamate transporter-1 (GLT-1) was not altered by OGD and guanosine. However, MEK and PKC inhibitions also abolished the guanosine effect of increasing cell-surface expression of GLT-1 in astrocytes subjected to OGD. Then, guanosine prevents oxidative damage and stimulates astrocytic glutamate uptake during ischemic events via adenosine A1 and A2A receptors and modulation of survival signaling pathways, contributing to microenvironment homeostasis that culminates in neuroprotection.
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Affiliation(s)
- Tharine Dal-Cim
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianopolis, SC, 88040-900, Brazil
- Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Gabriela G Poluceno
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianopolis, SC, 88040-900, Brazil
- Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Débora Lanznaster
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianopolis, SC, 88040-900, Brazil
- Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Karen A de Oliveira
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianopolis, SC, 88040-900, Brazil
- Programa de Pós-graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Claudia B Nedel
- Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Carla I Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianopolis, SC, 88040-900, Brazil.
- Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil.
- Programa de Pós-graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil.
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Gegelashvili G, Bjerrum OJ. Glutamate transport system as a key constituent of glutamosome: Molecular pathology and pharmacological modulation in chronic pain. Neuropharmacology 2019; 161:107623. [PMID: 31047920 DOI: 10.1016/j.neuropharm.2019.04.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 01/07/2023]
Abstract
Neural uptake of glutamate is executed by the structurally related members of the SLC1A family of solute transporters: GLAST/EAAT1, GLT-1/EAAT2, EAAC1/EAAT3, EAAT4, ASCT2. These plasma membrane proteins ensure supply of glutamate, aspartate and some neutral amino acids, including glutamine and cysteine, for synthetic, energetic and signaling purposes, whereas effective removal of glutamate from the synaptic cleft shapes excitatory neurotransmission and prevents glutamate toxicity. Glutamate transporters (GluTs) possess also receptor-like properties and can directly initiate signal transduction. GluTs are physically linked to other glutamate signaling-, transporting- and metabolizing molecules (e.g., glutamine transporters SNAT3 and ASCT2, glutamine synthetase, NMDA receptor, synaptic vesicles), as well as cellular machineries fueling the transmembrane transport of glutamate (e.g., ion gradient-generating Na/K-ATPase, glycolytic enzymes, mitochondrial membrane- and matrix proteins, glucose transporters). We designate this supramolecular functional assembly as 'glutamosome'. GluTs play important roles in the molecular pathology of chronic pain, due to the predominantly glutamatergic nature of nociceptive signaling in the spinal cord. Down-regulation of GluTs often precedes or occurs simultaneously with development of pain hypersensitivity. Pharmacological inhibition or gene knock-down of spinal GluTs can induce/aggravate pain, whereas enhancing expression of GluTs by viral gene transfer can mitigate chronic pain. Thus, functional up-regulation of GluTs is turning into a prospective pharmacotherapeutic approach for the management of chronic pain. A number of novel positive pharmacological regulators of GluTs, incl. pyridazine derivatives and β-lactams, have recently been introduced. However, design and development of new analgesics based on this principle will require more precise knowledge of molecular mechanisms underlying physiological or aberrant functioning of the glutamate transport system in nociceptive circuits. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Georgi Gegelashvili
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark; Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia.
| | - Ole Jannik Bjerrum
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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Kristensen BW, Blaabjerg M, Noraberg J, Zimmer J. Long-term, Repeated Dose In Vitro Neurotoxicity of the Glutamate Receptor Antagonist L-AP3, Demonstrated in Rat Hippocampal Slice Cultures by Using Continuous Propidium Iodide Incubation. Altern Lab Anim 2019; 35:211-21. [PMID: 17559310 DOI: 10.1177/026119290703500208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most in vitro models are only used to assess short-term effects of test compounds. However, as demonstrated here, hippocampal slice cultures can be used for long-term studies. The test compound used was the metabotropic glutamate receptor antagonist, L(+)-2-amino-3-phosphonopropionic acid (L-AP3), which is known to be toxic in vivo after subchronic, but not acute, administration. Degenerative effects were monitored by measuring the cellular uptake of propidium iodide (PI; continuously present in the medium) and lactate dehydrogenase (LDH) leakage, and by using a panel of histological stains. Hippocampal slices, derived from 2-3 day old rats and grown for 3 weeks, were subsequently exposed for the next 3 weeks to 0, 10 or 100microM L-AP3, with PI (2microM) in the culture medium. Exposure to 100microM L-AP3 induced severe toxicity after 4-6 days, shown by massive PI uptake, LDH leakage, changes in MAP2 and GFAP immunostaining, and in Nissl and Timm staining. In contrast, 10microM L-AP3 did not induce detectable neuronal degeneration. Treatment with the NMDA receptor antagonist, MK-801, or the AMPA/KA receptor antagonist NBQX, together with 100microM L-AP3, reduced neurodegeneration down to close to control values. It is concluded that continuous incubation of hippocampal slice cultures with PI is technically feasible for use in studies of inducible neuronal degeneration over time.
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Affiliation(s)
- Bjarne W Kristensen
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Odense, Denmark
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10
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Spampinato SF, Copani A, Nicoletti F, Sortino MA, Caraci F. Metabotropic Glutamate Receptors in Glial Cells: A New Potential Target for Neuroprotection? Front Mol Neurosci 2018; 11:414. [PMID: 30483053 PMCID: PMC6243036 DOI: 10.3389/fnmol.2018.00414] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/25/2018] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are characterized by excitotoxicity and neuroinflammation that finally lead to slow neuronal degeneration and death. Although neurons are the principal target, glial cells are important players as they contribute by either exacerbating or dampening the events that lead to neuroinflammation and neuronal damage. A dysfunction of the glutamatergic system is a common event in the pathophysiology of these diseases. Metabotropic glutamate (mGlu) receptors belong to a large family of G protein-coupled receptors largely expressed in neurons as well as in glial cells. They often appear overexpressed in areas involved in neurodegeneration, where they can modulate glutamatergic transmission. Of note, mGlu receptor upregulation may involve microglia or, even more frequently, astrocytes, where their activation causes release of factors potentially able to influence neuronal death. The expression of mGlu receptors has been also reported on oligodendrocytes, a glial cell type specifically involved in the development of multiple sclerosis. Here we will provide a general overview on the possible involvement of mGlu receptors expressed on glial cells in the pathogenesis of different neurodegenerative disorders and the potential use of subtype-selective mGlu receptor ligands as candidate drugs for the treatment of neurodegenerative disorders. Negative allosteric modulators (NAM) of mGlu5 receptors might represent a relevant pharmacological tool to develop new neuroprotective strategies in these diseases. Recent evidence suggests that targeting astrocytes and microglia with positive allosteric modulators (PAM) of mGlu3 receptor or oligodendrocytes with mGlu4 PAMS might represent novel pharmacological approaches for the treatment of neurodegenerative disorders.
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Affiliation(s)
| | - Agata Copani
- Department of Drug Sciences, University of Catania, Catania, Italy.,Institute of Biostructure and Bioimaging, National Research Council, Catania, Italy
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico, Pozzilli, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy.,Oasi Research Institute, Istituto di Ricovero e Cura a Carattere Scientifico, Troina, Italy
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11
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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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12
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Mironova YS, Zhukova NG, Zhukova IA, Alifirova VM, Izhboldina OP, Latypova AV. Parkinson's disease and glutamatergic system. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:138-142. [DOI: 10.17116/jnevro201811851138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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13
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Grabiec U, Hohmann T, Hammer N, Dehghani F. Organotypic Hippocampal Slice Cultures As a Model to Study Neuroprotection and Invasiveness of Tumor Cells. J Vis Exp 2017. [PMID: 28872113 DOI: 10.3791/55359] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. This model is suitable for addressing different research questions that involve studies on neuroprotection, electrophysiological experiments on neurons, neuronal networks or tumor invasion. The hippocampal architecture and neuronal activity in multisynaptic circuits are well conserved in OHSC, even though the slicing procedure itself initially lesions and leads to formation of a glial scar. The scar formation alters presumably the mechanical properties and diffusive behavior of small molecules, etc. Slices allow the monitoring of time dependent processes after brain injury without animal surgery, and studies on interactions between various brain-derived cell types, namely astrocytes, microglia and neurons under both physiological and pathological conditions. An ambivalent aspect of this model is the absence of blood flow and immune blood cells. During the progression of the neuronal injury, migrating immune cells from the blood play an important role. As those cells are missing in slices, the intrinsic processes in the culture may be observed without external interference. Moreover, in OHSC the composition of the medium-external environment is precisely controlled. A further advantage of this method is the lower number of sacrificed animals compared to standard preparations. Several OHSC can be obtained from one animal making simultaneous studies with multiple treatments in one animal possible. For these reasons, OHSC are well suited to analyze the effects of new protective therapeutics after tissue damage or during tumor invasion. The protocol presented here describes a preparation method of OHSC that allows generating highly reproducible, well preserved slices that can be used for a variety of experimental research, like neuroprotection or tumor invasion studies.
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Affiliation(s)
- Urszula Grabiec
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg;
| | - Tim Hohmann
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg
| | | | - Faramarz Dehghani
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg
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14
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Glutamate Transport System as a Novel Therapeutic Target in Chronic Pain: Molecular Mechanisms and Pharmacology. ADVANCES IN NEUROBIOLOGY 2017; 16:225-253. [PMID: 28828613 DOI: 10.1007/978-3-319-55769-4_11] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The vast majority of peripheral neurons sensing noxious stimuli and conducting pain signals to the dorsal horn of the spinal cord utilize glutamate as a chemical transmitter of excitation. High-affinity glutamate transporter subtypes GLAST/EAAT1, GLT1/EAAT2, EAAC1/EAAT3, and EAAT4, differentially expressed on sensory neurons, postsynaptic spinal interneurons, and neighboring glia, ensure fine modulation of glutamate neurotransmission in the spinal cord. The glutamate transport system seems to play important roles in molecular mechanisms underlying chronic pain and analgesia. Downregulation of glutamate transporters (GluTs) often precedes or occurs simultaneously with development of hypersensitivity to thermal or tactile stimuli in various models of chronic pain. Moreover, antisense knockdown or pharmacological inhibition of these membrane proteins can induce or aggravate pain. In contrast, upregulation of GluTs by positive pharmacological modulators or by viral gene transfer to the spinal cord can reverse the development of such pathological hypersensitivity. Furthermore, some multi-target drugs displaying analgesic properties (e.g., tricyclic antidepressant amitriptyline, riluzole, anticonvulsant valproate, tetracycline antibiotic minocycline, β-lactam antibiotic ceftriaxone and its structural analog devoid of antibacterial activity, clavulanic acid) can significantly increase the spinal glutamate uptake. Thus, mounting evidence points at GluTs as prospective therapeutic target for chronic pain treatment. However, design and development of new analgesics based on the modulation of glutamate uptake will require more precise knowledge of molecular mechanisms underlying physiological or aberrant functioning of this transport system in the spinal cord.
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15
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Lanznaster D, Dal-Cim T, Piermartiri TCB, Tasca CI. Guanosine: a Neuromodulator with Therapeutic Potential in Brain Disorders. Aging Dis 2016; 7:657-679. [PMID: 27699087 PMCID: PMC5036959 DOI: 10.14336/ad.2016.0208] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/08/2016] [Indexed: 12/20/2022] Open
Abstract
Guanosine is a purine nucleoside with important functions in cell metabolism and a protective role in response to degenerative diseases or injury. The past decade has seen major advances in identifying the modulatory role of extracellular action of guanosine in the central nervous system (CNS). Evidence from rodent and cell models show a number of neurotrophic and neuroprotective effects of guanosine preventing deleterious consequences of seizures, spinal cord injury, pain, mood disorders and aging-related diseases, such as ischemia, Parkinson’s and Alzheimer’s diseases. The present review describes the findings of in vivo and in vitro studies and offers an update of guanosine effects in the CNS. We address the protein targets for guanosine action and its interaction with glutamatergic and adenosinergic systems and with calcium-activated potassium channels. We also discuss the intracellular mechanisms modulated by guanosine preventing oxidative damage, mitochondrial dysfunction, inflammatory burden and modulation of glutamate transport. New and exciting avenues for future investigation into the protective effects of guanosine include characterization of a selective guanosine receptor. A better understanding of the neuromodulatory action of guanosine will allow the development of therapeutic approach to brain diseases.
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Affiliation(s)
- Débora Lanznaster
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Tharine Dal-Cim
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Tetsadê C B Piermartiri
- 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil; 3CAPES Foundation, Ministry of Education of Brazil, Brasília - DF 70040-020, Brazil
| | - Carla I Tasca
- 1Departamento de Bioquímica,; 2Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina-UFSC, Campus Trindade, 88040-900, Florianópolis, SC, Brazil
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16
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Kuebler ES, Tauskela JS, Aylsworth A, Zhao X, Thivierge JP. Burst predicting neurons survive an in vitro glutamate injury model of cerebral ischemia. Sci Rep 2015; 5:17718. [PMID: 26648112 PMCID: PMC4673430 DOI: 10.1038/srep17718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/04/2015] [Indexed: 12/29/2022] Open
Abstract
Neuronal activity in vitro exhibits network bursts characterized by brief periods of increased spike rates. Recent work shows that a subpopulation of neurons reliably predicts the occurrence of network bursts. Here, we examined the role of burst predictors in cultures undergoing an in vitro model of cerebral ischemia. Dissociated primary cortical neurons were plated on multielectrode arrays and spontaneous activity was recorded at 17 days in vitro (DIV). This activity was characterized by neuronal avalanches where burst statistics followed a power law. We identified burst predictors as channels that consistently fired immediately prior to network bursts. The timing of these predictors relative to bursts followed a skewed distribution that differed sharply from a null model based on branching ratio. A portion of cultures were subjected to an excitotoxic insult (DIV 18). Propidium iodine and fluorescence imaging confirmed cell death in these cultures. While the insult did not alter the distribution of avalanches, it resulted in alterations in overall spike rates. Burst predictors, however, maintained baseline levels of activity. The resilience of burst predictors following excitotoxic insult suggests a key role of these units in maintaining network activity following injury, with implications for the selective effects of ischemia in the brain.
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Affiliation(s)
- Eric S Kuebler
- Center for Neural Dynamics and School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
| | - Joseph S Tauskela
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Amy Aylsworth
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Xigeng Zhao
- Department of Translational Bioscience, Human Health Therapeutics, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Jean-Philippe Thivierge
- Center for Neural Dynamics and School of Psychology, University of Ottawa, Ottawa, Ontario, Canada
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17
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Martins WC, Tasca CI, Cimarosti H. Battling Alzheimer's Disease: Targeting SUMOylation-Mediated Pathways. Neurochem Res 2015; 41:568-78. [PMID: 26227998 DOI: 10.1007/s11064-015-1681-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 06/29/2015] [Accepted: 07/22/2015] [Indexed: 01/10/2023]
Abstract
SUMO (small ubiquitin-like modifier) conjugation is a critically important control process in all eukaryotic cells, because it acts as a biochemical switch and regulates the function of hundreds of proteins in many different pathways. Although the diverse functional consequences and molecular targets of SUMOylation remain largely unknown, SUMOylation is becoming increasingly implicated in the pathophysiology of Alzheimer's disease (AD). Apart from the central SUMO-modified disease-associated proteins, such as amyloid precursor protein, amyloid β, and tau, SUMOylation also regulates several other processes underlying AD. These are involved in inflammation, mitochondrial dynamics, synaptic transmission and plasticity, as well as in protective responses to cell stress. Herein, we review current reports on the involvement of SUMOylation in AD, and present an overview of potential SUMO targets and pathways underlying AD pathogenesis.
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Affiliation(s)
- Wagner Carbolin Martins
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Carla Inês Tasca
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil
| | - Helena Cimarosti
- Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC), Campus Trindade, Florianópolis, SC, 88040-900, Brazil.
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18
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Buendia I, Gómez-Rangel V, González-Lafuente L, Parada E, León R, Gameiro I, Michalska P, Laudon M, Egea J, López MG. Neuroprotective mechanism of the novel melatonin derivative Neu-P11 in brain ischemia related models. Neuropharmacology 2015; 99:187-95. [PMID: 26188145 DOI: 10.1016/j.neuropharm.2015.07.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 11/28/2022]
Abstract
Stopping the ischemic cascade by targeting its components is a potential strategy for acute ischemic stroke treatment. During ischemia and especially over reperfusion, oxidative stress plays a major role in causing neuronal cell death. Melatonin has been previously reported to provide neuroprotective effects in in vivo models of stroke by a mechanism that implicates melatonin receptors. In this context, this study was planned to test the potential neuroprotective effects of the novel melatonin MT1/MT2 receptor agonist, Neu-P11, against brain ischemia in in vitro and in vivo models, and to elucidate its underlying mechanism of action. Neu-P11 proved to be a good antioxidant, to protect against glutamate-induced excitotoxicity and oxygen and glucose deprivation in hippocampal slices, and to reduce infarct volume in an in vivo stroke model. Regarding its mechanism of action, the protective effect of Neu-P11 was reverted by luzindole (melatonin receptor antagonist), AG490 (JAK2 inhibitor), LY294002 (PI3/AKT inhibitor) and PD98059 (MEK/ERK1/2 inhibitor). In conclusion, Neu-P11 affords neuroprotection against brain ischemia in in vitro and in vivo models by activating a pro-survival signaling pathway that involves melatonin receptors, JAK/STAT, PI3K/Akt and MEK/ERK1/2.
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Affiliation(s)
- Izaskun Buendia
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Vanessa Gómez-Rangel
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura González-Lafuente
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Esther Parada
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rafael León
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Isabel Gameiro
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Patrycja Michalska
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Moshe Laudon
- Neurim Pharmaceuticals Ltd., 27 Habarzel St, Tel-Aviv 6971039, Israel
| | - Javier Egea
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, Spain
| | - Manuela G López
- Instituto Teófilo Hernando (ITH), Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
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19
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Gegelashvili G, Bjerrum OJ. High-affinity glutamate transporters in chronic pain: an emerging therapeutic target. J Neurochem 2014; 131:712-30. [DOI: 10.1111/jnc.12957] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/18/2014] [Accepted: 09/25/2014] [Indexed: 01/13/2023]
Affiliation(s)
- Georgi Gegelashvili
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
- Institute of Chemical Biology; Ilia State University; Tbilisi Georgia
| | - Ole J. Bjerrum
- Department of Drug Design and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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20
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Thrombin-Facilitated Efflux of d-[3H]-Aspartate from Cultured Astrocytes and Neurons Under Hyponatremia and Chemical Ischemia. Neurochem Res 2014; 39:1219-31. [DOI: 10.1007/s11064-014-1300-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 03/26/2014] [Accepted: 03/28/2014] [Indexed: 01/17/2023]
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21
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Dal-Cim T, Ludka FK, Martins WC, Reginato C, Parada E, Egea J, López MG, Tasca CI. Guanosine controls inflammatory pathways to afford neuroprotection of hippocampal slices under oxygen and glucose deprivation conditions. J Neurochem 2013; 126:437-50. [DOI: 10.1111/jnc.12324] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 05/02/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Tharine Dal-Cim
- Departamento de Bioquímica; Centro de Ciências Biológicas; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - Fabiana K. Ludka
- Departamento de Bioquímica; Centro de Ciências Biológicas; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
- Curso de Farmácia; Universidade do Contestado; Canoinhas SC Brazil
| | - Wagner C. Martins
- Departamento de Bioquímica; Centro de Ciências Biológicas; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - Charlise Reginato
- Departamento de Bioquímica; Centro de Ciências Biológicas; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
| | - Esther Parada
- Departamento de Farmacología y Terapéutica; Facultad de Medicina; Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
| | - Javier Egea
- Departamento de Farmacología y Terapéutica; Facultad de Medicina; Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
| | - Manuela G. López
- Departamento de Farmacología y Terapéutica; Facultad de Medicina; Instituto Teófilo Hernando; Universidad Autónoma de Madrid; Madrid Spain
| | - Carla I. Tasca
- Departamento de Bioquímica; Centro de Ciências Biológicas; Universidade Federal de Santa Catarina; Florianópolis SC Brazil
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22
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Stobart JL, Anderson CM. Multifunctional role of astrocytes as gatekeepers of neuronal energy supply. Front Cell Neurosci 2013; 7:38. [PMID: 23596393 PMCID: PMC3622037 DOI: 10.3389/fncel.2013.00038] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 03/26/2013] [Indexed: 01/01/2023] Open
Abstract
Dynamic adjustments to neuronal energy supply in response to synaptic activity are critical for neuronal function. Glial cells known as astrocytes have processes that ensheath most central synapses and express G-protein-coupled neurotransmitter receptors and transporters that respond to neuronal activity. Astrocytes also release substrates for neuronal oxidative phosphorylation and have processes that terminate on the surface of brain arterioles and can influence vascular smooth muscle tone and local blood flow. Membrane receptor or transporter-mediated effects of glutamate represent a convergence point of astrocyte influence on neuronal bioenergetics. Astrocytic glutamate uptake drives glycolysis and subsequent shuttling of lactate from astrocytes to neurons for oxidative metabolism. Astrocytes also convert synaptically reclaimed glutamate to glutamine, which is returned to neurons for glutamate salvage or oxidation. Finally, astrocytes store brain energy currency in the form of glycogen, which can be mobilized to produce lactate for neuronal oxidative phosphorylation in response to glutamatergic neurotransmission. These mechanisms couple synaptically driven astrocytic responses to glutamate with release of energy substrates back to neurons to match demand with supply. In addition, astrocytes directly influence the tone of penetrating brain arterioles in response to glutamatergic neurotransmission, coordinating dynamic regulation of local blood flow. We will describe the role of astrocytes in neurometabolic and neurovascular coupling in detail and discuss, in turn, how astrocyte dysfunction may contribute to neuronal bioenergetic deficit and neurodegeneration. Understanding the role of astrocytes as a hub for neurometabolic and neurovascular coupling mechanisms is a critical underpinning for therapeutic development in a broad range of neurodegenerative disorders characterized by chronic generalized brain ischemia and brain microvascular dysfunction.
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Affiliation(s)
- Jillian L Stobart
- Division of Neurodegenerative Disorders, Department of Pharmacology and Therapeutics, St. Boniface Hospital Research, University of Manitoba Winnipeg, MB, Canada ; Department of Nuclear Medicine, Institute of Pharmacology and Toxicology, University of Zürich Zürich, Switzerland
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23
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Liu CH, Jiao H, Guo ZH, Peng Y, Wang WZ. Up-regulated GLT-1 resists glutamate toxicity and attenuates glutamate-induced calcium loading in cultured neurocytes. Basic Clin Pharmacol Toxicol 2012; 112:19-24. [PMID: 22998524 DOI: 10.1111/bcpt.12011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 09/03/2012] [Indexed: 11/28/2022]
Abstract
Glutamate transporter-1 (GLT-1) plays a dual role in glutamate transportation: both normally devotion to the clearance of glutamate and during some pathological conditions extruding glutamate to the extracellular space. Therefore, it is uncertain whether increased expression of GLT-1 will actually be helpful against glutamate excitotoxicity. In this study, GLT-1 up-regulation was induced by ceftriaxone, and L-glutamate was added to induce glutamate toxicity in primary cultured rat cortical cells. The results showed that up-regulated GLT-1 induced by 1 μM ceftriaxone for 2 days markedly increased cell viability, decreased apoptotic cell death and alleviated ultrastructural damage induced by 50 μM glutamate 15 min. as well as promoted L-[(3) H]-glutamate uptake in cultured cells. GLT-1 up-regulation had no effect on the intracellular free calcium concentration ([Ca(2+) ](i) ) in the resting situation, while relieved intracellular calcium overloading by reducing the elevation and promoting the recovery of [Ca(2+) ](i) following stimulation of 50 μM glutamate for 2 min. Applying 100 μM dihydrokainic acid (GLT-1 antagonist) 30 sec. before glutamate eliminated the above effect of GLT-1 up-regulation on [Ca(2+) ](i) . In conclusion, GLT-1 up-regulation induced by ceftriaxone plays a positive glutamate transporting role against glutamate toxicity in primary cultured rat cortical cells.
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Affiliation(s)
- Chun-hua Liu
- Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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Guanosine is neuroprotective against oxygen/glucose deprivation in hippocampal slices via large conductance Ca²+-activated K+ channels, phosphatidilinositol-3 kinase/protein kinase B pathway activation and glutamate uptake. Neuroscience 2011; 183:212-20. [PMID: 21435378 DOI: 10.1016/j.neuroscience.2011.03.022] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 03/04/2011] [Accepted: 03/09/2011] [Indexed: 12/20/2022]
Abstract
Guanine derivatives (GD) have been implicated in many relevant brain extracellular roles, such as modulation of glutamate transmission and neuronal protection against excitotoxic damage. GD are spontaneously released to the extracellular space from cultured astrocytes and during oxygen/glucose deprivation (OGD). The aim of this study has been to evaluate the potassium channels and phosphatidilinositol-3 kinase (PI3K) pathway involvement in the mechanisms related to the neuroprotective role of guanosine in rat hippocampal slices subjected to OGD. The addition of guanosine (100 μM) to hippocampal slices subjected to 15 min of OGD and followed by 2 h of re-oxygenation is neuroprotective. The presence of K+ channel blockers, glibenclamide (20 μM) or apamin (300 nM), revealed that neuroprotective effect of guanosine was not dependent on ATP-sensitive K+ channels or small conductance Ca²+-activated K+ channels. The presence of charybdotoxin (100 nM), a large conductance Ca²+-activated K+ channel (BK) blocker, inhibited the neuroprotective effect of guanosine. Hippocampal slices subjected to OGD and re-oxygenation showed a significant reduction of glutamate uptake. Addition of guanosine in the re-oxygenation period has blocked the reduction of glutamate uptake. This guanosine effect was inhibited when hippocampal slices were pre-incubated with charybdotoxin or wortmanin (a PI3K inhibitor, 1 μM) in the re-oxygenation period. Guanosine promoted an increase in Akt protein phosphorylation. However, the presence of charybdotoxin blocked such effect. In conclusion, the neuroprotective effect of guanosine involves augmentation of glutamate uptake, which is modulated by BK channels and the activation of PI3K pathway. Moreover, neuroprotection caused by guanosine depends on the increased expression of phospho-Akt protein.
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25
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Bagetta G, Morrone LA, Rombolà L, Amantea D, Russo R, Berliocchi L, Sakurada S, Sakurada T, Rotiroti D, Corasaniti MT. Neuropharmacology of the essential oil of bergamot. Fitoterapia 2010; 81:453-61. [DOI: 10.1016/j.fitote.2010.01.013] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/02/2010] [Accepted: 01/10/2010] [Indexed: 01/25/2023]
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26
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Shirasaki Y, Sugimura M, Sato T. Bromocriptine, an ergot alkaloid, inhibits excitatory amino acid release mediated by glutamate transporter reversal. Eur J Pharmacol 2010; 643:48-57. [PMID: 20599932 DOI: 10.1016/j.ejphar.2010.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 05/11/2010] [Accepted: 06/04/2010] [Indexed: 11/26/2022]
Abstract
Bromocriptine, a dopamine D(2) receptor agonist, has widely been used for patients with Parkinson's disease. The aim of the present study was to investigate the effect of bromocriptine on glutamate transporter. Since the astroglial glutamate transporter GLT-1 (EAAT2) is the predominant isoform in the forebrain, we generated EAAT2-expressing human embryonic kidney cells and immortalized mouse astrocytes. In the present studies, we observed a GLT-1-immunoreactive band and significant Na(+)-dependent d-[(3)H] aspartate uptake. Furthermore, the glutamate transporter inhibitors, dl-threo-beta-benzyloxyaspartic acid (TBOA) and dihydrokainate (DHK), displayed a dose-dependent reduction of d-[(3)H] aspartate uptake in both types of cells. In contrast, cells exposed to either chemical anoxia or high KCl elicited a marked release of d-[(3)H] aspartate, and the release was inhibited by TBOA and DHK, implying the contribution of glutamate transporter reversal. Interestingly, we found that bromocriptine dose-dependently inhibits d-[(3)H] aspartate release elicited by chemical anoxia or high KCl, while no changes occurred in the uptake. The inhibitory action of bromocriptine was not affected by sulpiride, a dopamine D(2) receptor antagonist. On the other hand, bromocriptine had no effect on swelling-induced d-[(3)H] aspartate release, which is mediated by volume-regulated anion channels. In vivo studies revealed that bromocriptine suppresses the excessive elevation of glutamate levels in gerbils subjected to transient forebrain ischemia in a manner similar to DHK. Taken together, these results provide evidence that bromocriptine inhibits excitatory amino acid release via reversed operation of GLT-1 without altering forward transport.
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Affiliation(s)
- Yasufumi Shirasaki
- Biological Research Laboratories, Daiichi-Sankyo Co., Ltd., Tokyo, Japan.
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A novel method for inducing focal ischemia in vitro. J Neurosci Methods 2010; 190:20-7. [PMID: 20417233 DOI: 10.1016/j.jneumeth.2010.04.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/15/2010] [Accepted: 04/15/2010] [Indexed: 11/23/2022]
Abstract
Current in vitro models of stroke involve applying oxygen-glucose deprived (OGD) media over an entire brain slice or plate of cultured neurons. Thus, these models fail to mimic the focal nature of stroke as observed clinically and with in vivo rodent models of stroke. Our aim was to develop a novel in vitro brain slice model of stroke that would mimic focal ischemia and thus allow for the investigation of events occurring in the penumbra. This was accomplished by focally applying OGD medium to a small portion of a brain slice while bathing the remainder of the slice with normal oxygenated media. This technique produced a focal infarct on the brain slice that increased as a function of time. Electrophysiological recordings made within the flow of the OGD solution ("core") revealed that neurons rapidly depolarized (anoxic depolarization; AD) in a manner similar to that observed in other stroke models. Edaravone, a known neuroprotectant, significantly delayed this onset of AD. Electrophysiological recordings made outside the flow of the OGD solution ("penumbra") revealed that neurons within this region progressively depolarized throughout the 75 min of OGD application. Edaravone attenuated this depolarization and doubled neuronal survival. Finally, synaptic transmission in the penumbra was abolished within 50 min of focal OGD application. These results suggest that this in vitro model mimics events that occur during focal ischemia in vivo and can be used to determine the efficacy of therapeutics that target neuronal survival in the core and/or penumbra.
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Nani F, Cifra A, Nistri A. Transient oxidative stress evokes early changes in the functional properties of neonatal rat hypoglossal motoneurons in vitro. Eur J Neurosci 2010; 31:951-66. [PMID: 20214680 DOI: 10.1111/j.1460-9568.2010.07108.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Oxidative stress of motoneurons is believed to be an important contributor to neurodegeneration underlying the familial (and perhaps even the sporadic) form of amyotrophic lateral sclerosis (ALS). This concept has generated numerous rodent genetic models with inborn oxidative stress to mimic the clinical condition. ALS is, however, a predominantly sporadic disorder probably triggered by environmental causes. Thus, it is interesting to understand how wild-type motoneurons react to strong oxidative stress as this response might cast light on the presymptomatic disease stage. The present study used, as a model, hypoglossal motoneurons from the rat brainstem slice to investigate how hydrogen peroxide could affect synaptic transmission and intrinsic motoneuron excitability in relation to their survival. Hydrogen peroxide (1 mm; 30 min) induced inward current or membrane depolarization accompanied by an increase in input resistance, enhanced firing and depressed spontaneous synaptic events. Despite enhanced intracellular oxidative processes, there was no death of motoneurons, although most cells were immunopositive for activating transcription factor 3, a stress-related transcription factor. Voltage-clamp experiments indicated increased frequency of excitatory or inhibitory miniature events, and reduced voltage-gated persistent currents of motoneurons. The global effect of this transient oxidative challenge was to depress the input flow from the premotor interneurons to motoneurons that became more excitable due to a combination of enhanced input resistance and impaired spike afterhyperpolarization. Our data show previously unreported changes in motoneuron activity associated with cell distress caused by a transient oxidative insult.
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Affiliation(s)
- Francesca Nani
- Neurobiology Sector, International School for Advanced Studies (SISSA), Via Beirut 2-4, 34151 Trieste, Italy
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Nathaniel TI, Saras A, Umesiri FE, Olajuyigbe F. Tolerance to oxygen nutrient deprivation in the hippocampal slices of the naked mole rats. J Integr Neurosci 2009; 8:123-36. [PMID: 19618484 DOI: 10.1142/s0219635209002149] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 05/04/2009] [Indexed: 11/18/2022] Open
Abstract
Hypoxia tolerance in the naked mole rats (Heterocephalus glaber) represents a unique physiological phenomenon characterized by the capability to regulate oxygen demand to attenuate energetically costly response to low oxygen condition. Several aspects of tolerance to hypoxia in the naked mole rat are consistent with a state of neuroprotection; however, it remains to be established if such protective capability is expressed in the brain cells of mole rats subjected to hypoxia insults. The objective of this study was to determine whether evidence of tolerance to oxygen nutrient deprivation exists in the chronic cultures of the naked mole rats hippocampal slices. We used oxygen nutrient deprivation (OND), an in vitro model of hypoxia tolerance, to determine neuronal survival in the hippocampal slices of mole rats and rats (Rattus sp.). Our results indicate that hippocampal slices of mole rats kept in hypoxic condition consistently tolerate OND right from the onset time of 5 hrs and the tolerance to OND is maintained for 24 hrs, suggesting that there is evidence of tolerance to OND in hippocampal slices of mole rats.
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Affiliation(s)
- Thomas I Nathaniel
- Center for Natural and Health Sciences, Science Department, Marywood University, 2300 Adams Avenue, Scranton, PA 18509, USA.
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Synaptopathy under conditions of altered gravity: changes in synaptic vesicle fusion and glutamate release. Neurochem Int 2009; 55:724-31. [PMID: 19631248 DOI: 10.1016/j.neuint.2009.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 07/14/2009] [Indexed: 11/22/2022]
Abstract
Glutamate release and synaptic vesicle heterotypic/homotypic fusion were characterized in brain synaptosomes of rats exposed to hypergravity (10 G, 1h). Stimulated vesicular exocytosis determined as KCl-evoked fluorescence spike of pH-sensitive dye acridine orange (AO) was decreased twice in synaptosomes under hypergravity conditions as compared to control. Sets of measurements demonstrated reduced ability of synaptic vesicles to accumulate AO ( approximately 10% higher steady-state baseline level of AO fluorescence). Experiments with preloaded l-[(14)C]glutamate exhibited similar amount of total glutamate accumulated by synaptosomes, equal concentration of ambient glutamate, but the enlarged level of cytoplasmic glutamate measuring as leakage from digitonin-permeabilized synaptosomes in hypergravity. Thus, it may be suggested that +G-induced changes in stimulated vesicular exocytosis were a result of the redistribution of intracellular pool of glutamate, i.e. a decrease in glutamate content of synaptic vesicles and an enrichment of the cytoplasmic glutamate level. To investigate the effect of hypergravity on the last step of exocytosis, i.e. membrane fusion, a cell-free system consisted of synaptic vesicles, plasma membrane vesicles, cytosolic proteins isolated from rat brain synaptosomes was used. It was found that hypergravity reduced the fusion competence of synaptic vesicles and plasma membrane vesicles, whereas synaptosomal cytosolic proteins became more active to promote membrane fusion. The total rate of homo- and heterotypic fusion reaction initiated by Ca(2+) or Mg(2+)/ATP remained unchanged under hypergravity conditions. Thus, hypergravity could induce synaptopathy that was associated with incomplete filling of synaptic vesicles with the neuromediator and changes in exocytotic release.
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Guanosine-5'-monophosphate induces cell death in rat hippocampal slices via ionotropic glutamate receptors activation and glutamate uptake inhibition. Neurochem Int 2009; 55:703-9. [PMID: 19576258 DOI: 10.1016/j.neuint.2009.06.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 06/19/2009] [Accepted: 06/23/2009] [Indexed: 12/23/2022]
Abstract
Guanine derivatives modulate the glutamatergic system through displacement of binding of glutamate to its receptors acting as antagonist of glutamate receptors in moderate to high micromolar concentrations. Guanosine-5'-monophosphate (GMP) is shown to be neuroprotective against glutamate- or oxygen/glucose deprivation-induced neurotoxicity and also against NMDA-induced apoptosis in hippocampal slices. However, in this study we are showing that high extracellular GMP concentrations (5mM) reduced cell viability in hippocampal brain slices. The toxic effect of GMP was not blocked by dipyridamole, a nucleoside transport inhibitor, nor mimicked by guanosine, suggesting an extracellular mode of action to GMP which does not involve its hydrolysis to guanosine. GMP-dependent cell damage was not blocked by P1 purinergic receptor antagonists, neither altered by adenosine A(1) or A(2A) receptor agonists. The blockage of the ionotropic glutamate receptors AMPA or NMDA, but not KA or metabotropic glutamate receptors, reversed the toxicity induced by GMP. GMP (5mM) induced a decrease in glutamate uptake into hippocampal slices, which was reversed by dl-TBOA. Therefore, GMP-induced hippocampal cell damage involves activation of ionotropic glutamate receptors and inhibition of glutamate transporters activity.
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Molz S, Tharine DC, Decker H, Tasca CI. GMP prevents excitotoxicity mediated by NMDA receptor activation but not by reversal activity of glutamate transporters in rat hippocampal slices. Brain Res 2008; 1231:113-20. [PMID: 18655777 DOI: 10.1016/j.brainres.2008.07.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 01/11/2023]
Abstract
Glutamate is the main excitatory neurotransmitter in the mammalian nervous system and is essential for its normal functions. However, overstimulation of glutamatergic system due to hyperactivation of NMDA receptors and/or impairment of glutamate reuptake system has been implicated in many acute and chronic neurological diseases. Regulation of extracellular glutamate concentrations relies on the function of glutamate transporters which can be reversed in situations related to excitotoxicity. Guanosine-5'-monophosphate (GMP), a guanine nucleotide which displays important extracellular roles, such as trophic effects to neurons and astrocytes, behaves as antagonist of glutamate receptors and is neuroprotective in hippocampal slices against excitotoxicity or ischemic conditions. Hippocampal slices exposed to 1 or 10 mM glutamate, or 100 microM NMDA with 10 microM glycine for 1 h and evaluated after 6 or 18 h, showed reduced cell viability and DNA fragmentation, respectively. Glutamate- or NMDA-induced cell death was prevented by 50 microM MK-801, but only NMDA-induced cell damage was prevented by GMP (1 mM). Glutamate-induced cell viability impairment and glutamate-induced l-[(3)H]glutamate release were both prevented by adding DL-TBOA (10 microM). Otherwise, NMDA-induced cell viability loss was not prevented by 10 microM of DL-TBOA and NMDA did not induce l-[(3)H]glutamate release. Our results demonstrate that GMP is neuroprotective when acting selectively at NMDA receptors. Glutamate-induced hippocampal slice damage and glutamate release were blocked by glutamate transporter inhibitor, indicating that glutamate-induced toxicity also involves the reversal of glutamate uptake, which cannot be prevented by GMP.
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Affiliation(s)
- Simone Molz
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, Florianópolis, SC, Brazil
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Weller ML, Stone IM, Goss A, Rau T, Rova C, Poulsen DJ. Selective overexpression of excitatory amino acid transporter 2 (EAAT2) in astrocytes enhances neuroprotection from moderate but not severe hypoxia-ischemia. Neuroscience 2008; 155:1204-11. [PMID: 18620031 DOI: 10.1016/j.neuroscience.2008.05.059] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 05/26/2008] [Indexed: 02/08/2023]
Abstract
Attempts have been made to elevate excitatory amino acid transporter 2 (EAAT2) expression in an effort to compensate for loss of function and expression associated with disease or pathology. Increased EAAT2 expression has been noted following treatment with beta-lactam antibiotics, and during ischemic preconditioning (IPC). However, both of these conditions induce multiple changes in addition to alterations in EAAT2 expression that could potentially contribute to neuroprotection. Therefore, the aim of this study was to selectively overexpress EAAT2 in astrocytes and characterize the cell type specific contribution of this transporter to neuroprotection. To accomplish this we used a recombinant adeno-associated virus vector, AAV1-glial fibrillary acidic protein (GFAP)-EAAT2, designed to selectively drive the overexpression of EAAT2 within astrocytes. Both viral-mediated gene delivery and beta-lactam antibiotic (penicillin-G) treatment of rat hippocampal slice cultures resulted in a significant increase in both the expression of EAAT2, and dihydrokainate (DHK) sensitive glutamate uptake. Penicillin-G provided significant neuroprotection in rat hippocampal slice cultures under conditions of both moderate and severe oxygen glucose deprivation (OGD). In contrast, viral-mediated overexpression of EAAT2 in astrocytes provided enhanced neuroprotection only following a moderate OGD insult. These results indicate that functional EAAT2 can be selectively overexpressed in astrocytes, leading to enhanced neuroprotection. However, this cell type specific increase in EAAT2 expression offers only limited protection compared to treatment with penicillin-G.
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Affiliation(s)
- M L Weller
- NIH COBRE Center for Structural and Functional Neuroscience, Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA.
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Hertz L. Bioenergetics of cerebral ischemia: a cellular perspective. Neuropharmacology 2008; 55:289-309. [PMID: 18639906 DOI: 10.1016/j.neuropharm.2008.05.023] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 05/14/2008] [Accepted: 05/14/2008] [Indexed: 12/27/2022]
Abstract
In cerebral ischemia survival of neurons, astrocytes, oligodendrocytes and endothelial cells is threatened during energy deprivation and/or following re-supply of oxygen and glucose. After a brief summary of characteristics of different cells types, emphasizing the dependence of all on oxidative metabolism, the bioenergetics of focal and global ischemia is discussed, distinguishing between events during energy deprivation and subsequent recovery attempt after re-circulation. Gray and white matter ischemia are described separately, and distinctions are made between mature and immature brains. Next comes a description of bioenergetics in individual cell types in culture during oxygen/glucose deprivation or exposure to metabolic inhibitors and following re-establishment of normal aerated conditions. Due to their expression of NMDA and non-NMDA receptors neurons and oligodendrocytes are exquisitely sensitive to excitotoxicity by glutamate, which reaches high extracellular concentrations in ischemic brain for several reasons, including failing astrocytic uptake. Excitotoxicity kills brain cells by energetic exhaustion (due to Na(+) extrusion after channel-mediated entry) combined with mitochondrial Ca(2+)-mediated injury and formation of reactive oxygen species. Many (but not all) astrocytes survive energy deprivation for extended periods, but after return to aerated conditions they are vulnerable to mitochondrial damage by cytoplasmic/mitochondrial Ca(2+) overload and to NAD(+) deficiency. Ca(2+) overload is established by reversal of Na(+)/Ca(2+) exchangers following Na(+) accumulation during Na(+)-K(+)-Cl(-) cotransporter stimulation or pH regulation, compensating for excessive acid production. NAD(+) deficiency inhibits glycolysis and eventually oxidative metabolism, secondary to poly(ADP-ribose)polymerase (PARP) activity following DNA damage. Hyperglycemia can be beneficial for neurons but increases astrocytic death due to enhanced acidosis.
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Affiliation(s)
- Leif Hertz
- College of Basic Medical Sciences, China Medical University, Shenyang, PR China.
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Goursaud S, Maloteaux JM, Hermans E. Activation of VIP/PACAP type 2 receptor by the peptide histidine isoleucine in astrocytes influences GLAST-mediated glutamate uptake. J Neurochem 2008; 105:1165-75. [DOI: 10.1111/j.1471-4159.2008.05231.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Colleoni S, Jensen AA, Landucci E, Fumagalli E, Conti P, Pinto A, De Amici M, Pellegrini-Giampietro DE, De Micheli C, Mennini T, Gobbi M. Neuroprotective effects of the novel glutamate transporter inhibitor (-)-3-hydroxy-4,5,6,6a-tetrahydro-3aH-pyrrolo[3,4-d]-isoxazole-4-carboxylic acid, which preferentially inhibits reverse transport (glutamate release) compared with glutamate reuptake. J Pharmacol Exp Ther 2008; 326:646-56. [PMID: 18451317 DOI: 10.1124/jpet.107.135251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
(+/-)-3-Hydroxy-4,5,6,6a-tetrahydro-3aH-pyrrolo [3,4 -d]-isoxazole-4-carboxylic acid (HIP-A) and (+/-)-3-hydroxy-4,5,6, 6a-tetrahydro-3aH-pyrrolo[3,4-d]isoxazole-6-carboxylic acid (HIP-B) are selective inhibitors of excitatory amino acid transporters (EAATs), as potent as DL-threo-beta-benzyloxyaspartic acid (TBOA). We report here that the active isomers are (-)-HIP-A and (+)-HIP-B, being approximately 150- and 10-fold more potent than the corresponding enantiomers as inhibitors of [3H]aspartate uptake in rat brain synaptosomes and hEAAT1-3-expressing cells. Comparable IC(50) values were found on the three hEAAT subtypes. (-)-HIP-A maintained the remarkable property, previously reported with the racemates, of inhibiting synaptosomal glutamate-induced [3H]D-aspartate release (reverse transport) at concentrations significantly lower than those inhibiting [3H]L-glutamate uptake. New data suggest that the noncompetitive-like interaction described previously is probably the consequence of an insurmountable, long-lasting impairment of EAAT's function. Some minutes of preincubation are required to induce this impairment, the duration of preincubation having more effect on inhibition of glutamate-induced release than of glutamate uptake. In organotypic rat hippocampal slices and mixed mouse brain cortical cultures, TBOA, but not (-)-HIP-A, had toxic effects. Under ischemic conditions, a neuroprotective effect was found with 10 to 30 microM (-)-HIP-A, but not with 10 to 30 microM TBOA or 100 microM (-)-HIP-A. The effect of (-)-HIP-A suggests that, under ischemia, EAATs mediate both release (reverse transport) and uptake of glutamate. The neuroprotection with the lower (-)-HIP-A concentrations may indicate a selective inhibition of the reverse transport confirming the data obtained in synaptosomes. The selective interference with glutamate-induced glutamate release might offer a new strategy for neuroprotective action.
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Affiliation(s)
- Simona Colleoni
- Istituto di Ricerche Farmacologiche "Mario Negri," 20156 Milan, Italy
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Synthesis of enantiomerically pure HIP-A and HIP-B and investigation of their activity as inhibitors of excitatory amino acid transporters. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Napier S, Bingham M. Pharmacology of Glutamate Transport in the CNS: Substrates and Inhibitors of Excitatory Amino Acid Transporters (EAATs) and the Glutamate/Cystine Exchanger System x c −. TOPICS IN MEDICINAL CHEMISTRY 2008. [PMCID: PMC7123079 DOI: 10.1007/7355_2008_026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
As the primary excitatory neurotransmitter in the mammalian CNS, l-glutamateparticipates not only in standard fast synaptic communication, but also contributes to higher order signalprocessing, as well as neuropathology. Given this variety of functional roles, interest has been growingas to how the extracellular concentrations of l-glutamate surroundingneurons are regulated by cellular transporter proteins. This review focuses on two prominent systems, eachof which appears capable of influencing both the signaling and pathological actions of l-glutamatewithin the CNS: the sodium-dependent excitatory amino acid transporters (EAATs) and the glutamate/cystineexchanger, system xc−(Sxc−). Whilethe family of EAAT subtypes limit access to glutamate receptors by rapidly and efficiently sequesteringl-glutamate in neurons and glia, Sxc−provides a route for the export of glutamate from cells into the extracellular environment. The primaryintent of this work is to provide an overview of the inhibitors and substrates that have been developedto delineate the pharmacological specificity of these transport systems, as well as be exploited as probeswith which to selectively investigate function. Particular attention is paid to the development of smallmolecule templates that mimic the structural properties of the endogenous substrates, l-glutamate,l-aspartate and l-cystine andhow strategic control of functional group position and/or the introduction of lipophilic R-groups can impactmultiple aspects of the transport process, including: subtype selectivity, inhibitory potency, and substrateactivity.
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Madsen KK, Larsson OM, Schousboe A. Regulation of excitation by GABA neurotransmission: focus on metabolism and transport. Results Probl Cell Differ 2008; 44:201-21. [PMID: 17579816 DOI: 10.1007/400_2007_036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The vast majority of excitatory synapses in the central nervous system (CNS) utilize glutamate as the neurotransmitter. The level of excitation appears to be under regulatory control by the major inhibitory neurotransmitter GABA, which is synthesized from glutamate by its decarboxylation catalysed by glutamate decarboxylase (GAD). The inactivation of GABA is brought about by high affinity GABA transporters located in the presynaptic GABAergic neurons as well as surrounding astrocytes and subsequently GABA may be metabolized by GABA-transaminase (GABA-T) ultimately allowing the carbon skeleton to enter the tricarboxylic acid (TCA) cycle for oxidative metabolism. In the presynaptic GABAergic neuron, GABA taken up seems, however, preferentially to enter the vesicular GABA pool and hence it is recycled as a transmitter. It has become clear that compounds acting as inhibitors at either the transporters or GABA-T are capable of regulating the inhibitory tonus thus controlling excitation. This has led to development of clinically efficatious antiepileptic drugs. This paper shall review recent progress in targeting these pharmacological entities.
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Affiliation(s)
- Karsten K Madsen
- Department of Pharmacology, Danish University of Pharmaceutical Sciences, Universitetsparken 2, 2100 Copenhagen, Denmark
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Sheldon AL, Robinson MB. The role of glutamate transporters in neurodegenerative diseases and potential opportunities for intervention. Neurochem Int 2007; 51:333-55. [PMID: 17517448 PMCID: PMC2075474 DOI: 10.1016/j.neuint.2007.03.012] [Citation(s) in RCA: 436] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 03/28/2007] [Accepted: 03/30/2007] [Indexed: 12/20/2022]
Abstract
Extracellular concentrations of the predominant excitatory neurotransmitter, glutamate, and related excitatory amino acids are maintained at relatively low levels to ensure an appropriate signal-to-noise ratio and to prevent excessive activation of glutamate receptors that can result in cell death. The latter phenomenon is known as 'excitotoxicity' and has been associated with a wide range of acute and chronic neurodegenerative disorders, as well as disorders that result in the loss of non-neural cells such as oligodendroglia in multiple sclerosis. Unfortunately clinical trials with glutamate receptor antagonists that would logically seem to prevent the effects of excessive receptor activation have been associated with untoward side effects or little clinical benefit. In the mammalian CNS, the extracellular concentrations of glutamate are controlled by two types of transporters; these include a family of Na(+)-dependent transporters and a cystine-glutamate exchange process, referred to as system X(c)(-). In this review, we will focus primarily on the Na(+)-dependent transporters. A brief introduction to glutamate as a neurotransmitter will be followed by an overview of the properties of these transporters, including a summary of the presumed physiologic mechanisms that regulate these transporters. Many studies have provided compelling evidence that impairing the function of these transporters can increase the sensitivity of tissue to deleterious effects of aberrant activation of glutamate receptors. Over the last decade, it has become clear that many neurodegenerative disorders are associated with a change in localization and/or expression of some of the subtypes of these transporters. This would suggest that therapies directed toward enhancing transporter expression might be beneficial. However, there is also evidence that glutamate transporters might increase the susceptibility of tissue to the consequences of insults that result in a collapse of the electrochemical gradients required for normal function such as stroke. In spite of the potential adverse effects of upregulation of glutamate transporters, there is recent evidence that upregulation of one of the glutamate transporters, GLT-1 (also called EAAT2), with beta-lactam antibiotics attenuates the damage observed in models of both acute and chronic neurodegenerative disorders. While it seems somewhat unlikely that antibiotics specifically target GLT-1 expression, these studies identify a potential strategy to limit excitotoxicity. If successful, this type of approach could have widespread utility given the large number of neurodegenerative diseases associated with decreases in transporter expression and excitotoxicity. However, given the massive effort directed at developing glutamate receptor agents during the 1990s and the relatively modest advances to date, one wonders if we will maintain the patience needed to carefully understand the glutamatergic system so that it will be successfully targeted in the future.
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Affiliation(s)
- Amanda L. Sheldon
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA. 19104-4318
- Departments of Pediatrics and Pharmacology, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA. 19104-4318
| | - Michael B. Robinson
- Departments of Pediatrics and Pharmacology, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA. 19104-4318
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Thomazi AP, Boff B, Pires TD, Godinho G, Battú CE, Gottfried C, Souza DO, Salbego C, Wofchuk ST. Profile of glutamate uptake and cellular viability in hippocampal slices exposed to oxygen and glucose deprivation: developmental aspects and protection by guanosine. Brain Res 2007; 1188:233-40. [PMID: 18053975 DOI: 10.1016/j.brainres.2007.10.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 10/16/2007] [Accepted: 10/17/2007] [Indexed: 11/30/2022]
Abstract
Stroke syndromes are a major cause of disability in middle and later life resulting in severe neuronal degeneration and loss of brain functions. In situations with energy failure, glutamate transport is impaired and high levels of this amino acid accumulate on the synaptic cleft. Our group has showed that guanosine exerts neuroprotection against neurotoxicity situations. The aim of this work is draw a post-ischemic profile of glutamate uptake and cell damage using an oxygen and glucose deprivation model (OGD) in hippocampal slices from young (P10) and adult (P60) rats, analyzing guanosine effect. OGD decreases glutamate uptake in both ages and recovery times, although decrease in cell viability was only observed 1 and 3 h after OGD in young and adult animals, respectively. Guanosine partially protected cell damage from 1 h in P10 and at 3 h in P60 rats and avoided glutamate uptake decrease from P10 rats at 3 h. The impairment of glutamate transporters since immediately after the insult observed here is probably due to an energetic failure; loss of cell viability was only observed from 1 h after OGD. The mechanism by which guanosine acts in the 'ischemic' model used here is still unknown, but evidence leads to its antiapoptotic effect.
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Affiliation(s)
- Ana Paula Thomazi
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, UFRGS, Ramiro Barcelos, Porto Alegre, RS, Brazil.
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Montero M, Nielsen M, Rønn LCB, Møller A, Noraberg J, Zimmer J. Neuroprotective effects of the AMPA antagonist PNQX in oxygen-glucose deprivation in mouse hippocampal slice cultures and global cerebral ischemia in gerbils. Brain Res 2007; 1177:124-35. [PMID: 17894933 DOI: 10.1016/j.brainres.2007.08.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/08/2007] [Accepted: 08/10/2007] [Indexed: 11/17/2022]
Abstract
PNQX (9-methyl-amino-6-nitro-hexahydro-benzo(F)quinoxalinedione) is a selective AMPA antagonist with demonstrated neuroprotective effects in focal ischemia in rats. Here we report corresponding effects in mouse hippocampal slice cultures subjected to oxygen and glucose deprivation (OGD) and in transient global cerebral ischemia in gerbils. For in vitro studies, hippocampal slice cultures derived from 7-day-old mice and grown for 14 days, were submersed in oxygen-glucose deprived medium for 30 min and exposed to PNQX for 24 h, starting together with OGD, immediately after OGD, or 2 h after OGD. For comparison, other cultures were exposed to the NMDA antagonist MK-801 using the same protocol. Both PNQX and MK-801 displayed significant neuroprotective effects in all hippocampal subfields when present during and after OGD. When added just after OGD, only PNQX retained some neuroprotective effect. When added 2 h after OGD neither PNQX nor MK-801 had an effect. Transient global cerebral ischemia was induced in Mongolian gerbils by occlusion of both common carotid arteries for 4.5 min, with PNQX (10 mg/kg) being injected i.p. 30, 60 and 90 min after the insult. Subsequent analysis of brain sections stained for the neurodegeneration marker Fluoro-Jade B and immunostained for the astroglial marker glial fibrillary acidic protein revealed a significant PNQX-induced decrease in neuronal cell death and astroglial activation. We conclude that, PNQX provided neuroprotection against both global cerebral ischemia in gerbils in vivo and oxygen-glucose deprivation in mouse hippocampal slice cultures.
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Affiliation(s)
- Maria Montero
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Winslowparken 21st, DK-5000 Odense C, Denmark.
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Oleskovicz SPB, Martins WC, Leal RB, Tasca CI. Mechanism of guanosine-induced neuroprotection in rat hippocampal slices submitted to oxygen-glucose deprivation. Neurochem Int 2007; 52:411-8. [PMID: 17822807 DOI: 10.1016/j.neuint.2007.07.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 07/17/2007] [Accepted: 07/25/2007] [Indexed: 12/23/2022]
Abstract
Guanine derivates have been implicated in many relevant extracellular roles, such as modulation of glutamate transmission, protecting neurons against excitotoxic damage. Guanine derivatives are spontaneously released to the extracellular space from cultured astrocytes during oxygen-glucose deprivation (OGD) and may act as trophic factors, glutamate receptors blockers or glutamate transport modulators, thus promoting neuroprotection. The aim of this study was to evaluate the mechanisms involved in the neuroprotective role of the nucleoside guanosine in rat hippocampal slices submitted to OGD, identifying a putative extracellular binding site and the intracellular signaling pathways related to guanosine-induced neuroprotection. Cell damage to hippocampal slices submitted to 15 min of OGD followed by 2 h of reperfusion was decreased by the addition of guanosine (100 microM) or guanosine-5'-monophosphate (GMP, 100 microM). The neuroprotective effect of guanosine was not altered by the addition of adenosine receptor antagonists, nucleosides transport inhibitor, glutamate receptor antagonists, glutamate transport inhibitors, and a non-selective Na(+) and Ca(2+) channel blocker. However, in a Ca(2+)-free medium (by adding EGTA), guanosine was ineffective. Nifedipine (a Ca(2+) channel blocker) increased the neuroprotective effect of guanosine and 4-aminopyridine, a K(+) channel blocker, reversed the neuroprotective effect of guanosine. Evaluation of the intracellular signaling pathways associated with guanosine-induced neuroprotection showed the involvement of PKA, PKC, MEK and PI-3 K pathways, but not CaMKII. Therefore, this study shows guanosine is acting via K(+) channels activation, depending on extracellular Ca(2+) levels and via modulation of the PKA, PKC, MEK and/or PI-3 K pathways.
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Affiliation(s)
- Scheyla P B Oleskovicz
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Trindade, 88040-900 Florianópolis, SC, Brazil
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Lipski J, Wan CK, Bai JZ, Pi R, Li D, Donnelly D. Neuroprotective potential of ceftriaxone in in vitro models of stroke. Neuroscience 2007; 146:617-29. [PMID: 17363173 DOI: 10.1016/j.neuroscience.2007.02.003] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 02/01/2007] [Accepted: 02/03/2007] [Indexed: 12/01/2022]
Abstract
Astrocytic glutamate transporters are considered an important target for neuroprotective therapies as the function of these transporters is abnormal in stroke and other neurological disorders associated with excitotoxicity. Recently, Rothstein et al., [Rothstein JD, Patel S, Regan MR, Haenggeli C, Huang YH, Bergles DE, Jin L, Dykes Hoberg M, Vidensky S, Chung DS, Toan SV, Bruijn LI, Su ZZ, Gupta P, Fisher PB (2005) Beta-lactam antibiotics offer neuroprotection by increasing glutamate transporter expression. Nature 433:73-77] reported that beta-lactam antibiotics (including ceftriaxone, which easily crosses the blood-brain barrier) increase glutamate transporter 1 (GLT-1) expression and reduce cell death resulting from oxygen-glucose deprivation (OGD) in dissociated embryonic cortical cultures. To determine whether a similar neuroprotective mechanism operates in more mature neurons, which show a different pattern of response to ischemia than primary cultures, we exposed acute hippocampal slices obtained from rats treated with ceftriaxone for 5 days (200 mg/kg; i.p.) to OGD. Whole-cell patch clamp recording of glutamate-induced N-methyl-d-aspartate (NMDA) currents from CA1 pyramidal neurons showed a larger potentiation of these currents after application of 15 microM dl-threo-beta-benzyloxyaspartic acid (TBOA; a potent blocker of glutamate transporters) in ceftriaxone-injected animals than in untreated animals, indicating increased glutamate transporter activity. Western blot analysis did not reveal GLT-1 upregulation in the hippocampus. Delay to OGD-induced hypoxic spreading depression (HSD) recorded in slices obtained from ceftriaxone-treated rats was longer (6.3+/-0.2 vs. 5.2+/-0.2 min; P<0.001) than that in the control group, demonstrating a neuroprotective action of the antibiotic in this model. The effect of ceftriaxone was also tested in organotypic hippocampal slices obtained from P7-9 rats (>14 days in vitro). OGD or glutamate (3.5-5.0 mM) damaged CA1 pyramidal neurons as assessed by propidium iodide (PI) fluorescence. Similar damage was observed after pre-treatment with ceftriaxone (10-200 microM; 5 days) and ceftriaxone exposure did not result in GLT-1 upregulation as assayed by Western blot. Treatment of slice cultures with dibutyryl cAMP (100-250 microM; 5 days) increased GLT-1 expression but did not reduce cell damage induced by OGD or glutamate. Thus we confirm the neuroprotective effect of antibiotic exposure on OGD-induced injury, but suggest that this action is related to independent modulation of transporter activity rather than to the level of GLT-1 protein expression. In addition, our results indicate that the protective effects of beta-lactam antibiotics are highly dependent on the experimental model.
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Affiliation(s)
- J Lipski
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92-019, Auckland 1142, New Zealand.
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Estrada-Sánchez AM, Camacho A, Montiel T, Massieu L. Cerebellar Granule Neurons are More Vulnerable to Transient Transport-Mediated Glutamate Release than to Glutamate Uptake Blockade. Correlation with Excitatory Amino Acids Levels. Neurochem Res 2007; 32:423-32. [PMID: 17268852 DOI: 10.1007/s11064-006-9243-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 11/29/2006] [Indexed: 10/23/2022]
Abstract
The extracellular concentration of glutamate is highly regulated due to its excitotoxic nature. Failure of glutamate uptake or reversed activation of its transporters contributes to neurodegeneration related to some pathological conditions. We have compared the neurotoxicity of the substrate glutamate uptake inhibitor, L-trans-pyrrolidine-2,4-dicarboxylate (PDC), which promotes glutamate release by hetero-exchange, with that of DL-threo-beta-benzyloxyaspartate (DL-TBOA), a non-substrate inhibitor, in cerebellar granule cell cultures. PDC substantially increases the extracellular concentration of glutamate during 30 min exposure and causes neuronal death at high concentrations, while DL-TBOA neurotoxicity is only observed after long-term exposure (8-24 h). During mitochondrial inhibition by 3-nitropropionic acid (3-NP), PDC-induced neuronal death is facilitated, but not that of DL-TBOA. In cultures containing a higher population of astrocytes DL-TBOA-induced increase in glutamate levels is more pronounced, but neuronal death is only triggered in the presence of 3-NP. Results suggest that cerebellar granule neurons are more vulnerable to acute transport-mediated glutamate release than to uptake blockade, which correlates with the extracellular excitatory amino acids levels.
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Affiliation(s)
- Ana María Estrada-Sánchez
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, México, D.F. CP 04510, México
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Morrone LA, Rombolà L, Pelle C, Corasaniti MT, Zappettini S, Paudice P, Bonanno G, Bagetta G. The essential oil of bergamot enhances the levels of amino acid neurotransmitters in the hippocampus of rat: implication of monoterpene hydrocarbons. Pharmacol Res 2006; 55:255-62. [PMID: 17196823 DOI: 10.1016/j.phrs.2006.11.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2006] [Revised: 11/29/2006] [Accepted: 11/29/2006] [Indexed: 10/23/2022]
Abstract
The effects of bergamot essential oil (BEO) on the release of amino acid neurotransmitters in rat hippocampus have been studied by in vivo microdialysis and by in vitro superfusion of isolated nerve terminals. Intraperitoneal administration of BEO (100microl/kg) significantly elevated the extracellular concentration of aspartate, glycine and taurine in a Ca(2+)-dependent manner. A dose-relation study generated a bell-shaped curve. When perfused into the hippocampus via the dialysis probe (20microl/20min), BEO produced a significant increase of extracellular aspartate, glycine, taurine as well as of GABA and glutamate. The augmentation of all amino acids was Ca(2+)-independent. Focally injected 1:1 diluted BEO preferentially caused extracellular increase of glutamate. Interestingly, this release appeared to be strictly Ca(2+)-dependent. BEO concentration-dependently enhanced the release of [(3)H]D-aspartate from superfused hippocampal synaptosomes. Similar results were obtained by monitoring the BEO-evoked release of endogenous glutamate. At relatively high concentrations, the BEO-induced [(3)H]d-aspartate release was almost entirely prevented by the glutamate transporter blocker dl-threo-beta-benzyloxyaspartic acid (DL-TBOA) and was Ca(2+)-independent. At relatively low concentrations the release of [(3)H]D-aspartate was only in part ( approximately 50%) DL-TBOA-sensitive and Ca(2+)-independent; the remaining portion of release was dependent on extracellular Ca(2+). Interestingly, the monoterpene hydrocarbon-free fraction of the essential oil appeared to be inactive while the bergapten-free fraction superimposed the releasing effect of BEO supporting the deduction that psoralens may not be implicated. To conclude, BEO contains into its volatile fraction still unidentified monoterpene hydrocarbons able to stimulate glutamate release by transporter reversal and/or by exocytosis, depending on the dose administered.
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Affiliation(s)
- Luigi A Morrone
- Department of Pharmacobiology and University Center for Adaptive Disorders and Headache (UCHAD), section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Arcavacata di Rende (CS), Italy
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Ross AP, Christian SL, Zhao HW, Drew KL. Persistent tolerance to oxygen and nutrient deprivation and N-methyl-D-aspartate in cultured hippocampal slices from hibernating Arctic ground squirrel. J Cereb Blood Flow Metab 2006; 26:1148-56. [PMID: 16395285 DOI: 10.1038/sj.jcbfm.9600271] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hibernating Arctic ground squirrel (hAGS), Spermophilus parryii, survive profound decreases in cerebral perfusion during torpor and return to normal blood flow during intermittent rewarming periods without neurologic damage. Hibernating AGS tolerate traumatic brain injury in vivo, and acute hippocampal slices from hibernating animals tolerate oxygen and glucose deprivation. It remains unclear, however, if neuroprotection results from intrinsic tissue properties or from differences in response to acute trauma associated with slice preparation. The goal of this work was therefore to determine whether an intrinsic tissue tolerance persists in chronic culture of AGS hippocampal slices at 37 degrees C. A second goal was to address N-methyl-D-aspartate (NMDA) receptor involvement and channel arrest as potential mechanisms of intrinsic tissue tolerance. Baseline neuronal survival and tolerance to oxygen and nutrient deprivation (OND), an in vitro model of ischemia-reperfusion, were assessed in the CA1 region of hippocampal slices from juvenile, hAGS and interbout euthermic AGS (ibeAGS). Early in culture (insult onset at 3 h), slices from both hAGS and ibeAGS tolerate OND (4 h deprivation followed by 20 h recovery) and 500 micromol/L NMDA plus 20 mmol/L KCl. Later in culture (insult onset at 24 h), tolerance persists in slices from hAGS but not in slices from ibeAGS. Ouabain (Na(+)K(+)ATPase inhibitor) administered 24 h in culture enhances survival of slices from hAGS (assessed 24 h later). Thus, tolerance to OND in slices from hAGS is due to intrinsic tissue properties likely involving NMDA receptors and ion channel arrest.
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Affiliation(s)
- Austin P Ross
- Alaskan Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks, 99775-7000, USA
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Rattray M, Bendotti C. Does excitotoxic cell death of motor neurons in ALS arise from glutamate transporter and glutamate receptor abnormalities? Exp Neurol 2006; 201:15-23. [PMID: 16806177 DOI: 10.1016/j.expneurol.2006.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 05/02/2006] [Accepted: 05/04/2006] [Indexed: 12/14/2022]
Affiliation(s)
- Marcus Rattray
- King's College London, Wolfson Centre for Age-Related Diseases, Guy's Hospital Campus, London SE1 1UL, UK
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Chechneva O, Dinkel K, Cavaliere F, Martinez-Sanchez M, Reymann KG. Anti-inflammatory treatment in oxygen-glucose-deprived hippocampal slice cultures is neuroprotective and associated with reduced cell proliferation and intact neurogenesis. Neurobiol Dis 2006; 23:247-59. [PMID: 16733089 DOI: 10.1016/j.nbd.2006.02.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2005] [Revised: 01/27/2006] [Accepted: 02/27/2006] [Indexed: 10/24/2022] Open
Abstract
Increased neurogenesis in response to brain injury is considered a mechanism of regeneration after neuronal loss. Using organotypic hippocampal cultures (OHC), we investigated the interplay between neuronal damage (propidium iodide uptake), microglia activation (OX-42 immunohistochemistry), cell proliferation (bromodeoxyuridine incorporation), and neurogenesis (double labeling of bromodeoxyuridine with doublecortin or beta-III tubulin) after oxygen-glucose deprivation (OGD). We observed that microglia activation and upregulation of pro-inflammatory cytokines mRNA preceded neuronal loss and was followed by increased cell proliferation. Neurogenesis was inhibited 3 days after OGD in both neurogenic zones of the slice, the dentate gyrus and the posterior periventricle (pPV). After 6 days, neurogenesis was restored and significantly increased in the pPV. Indomethacin or minocycline reduced the OGD-induced damage, proliferation, and increase of microglia. Both agents did not interfere with OGD-induced pPV neurogenesis. Our study shows for the first time that neuroprotection against OGD-induced damage in OHC by anti-inflammatory treatment is associated with intact neurogenesis.
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Affiliation(s)
- Olga Chechneva
- Leibniz Institute for Neurobiology, Project Group Neuropharmacology, Magdeburg, Germany.
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Bonde C, Noraberg J, Noer H, Zimmer J. Ionotropic glutamate receptors and glutamate transporters are involved in necrotic neuronal cell death induced by oxygen-glucose deprivation of hippocampal slice cultures. Neuroscience 2006; 136:779-94. [PMID: 16344151 DOI: 10.1016/j.neuroscience.2005.07.020] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 06/27/2005] [Accepted: 07/12/2005] [Indexed: 11/18/2022]
Abstract
Organotypic hippocampal slice cultures represent a feasible model for studies of cerebral ischemia and the role of ionotropic glutamate receptors in oxygen-glucose deprivation-induced neurodegeneration. New results and a review of existing data are presented in the first part of this paper. The role of glutamate transporters, with special reference to recent results on inhibition of glutamate transporters under normal and energy-failure (ischemia-like) conditions is reviewed in the last part of the paper. The experimental work is based on hippocampal slice cultures derived from 7 day old rats and grown for about 3 weeks. In such cultures we investigated the subfield neuronal susceptibility to oxygen-glucose deprivation, the type of induced cell death and the involvement of ionotropic glutamate receptors. Hippocampal slice cultures were also used in our studies on glutamate transporters reviewed in the last part of this paper. Neurodegeneration was monitored and/or shown by cellular uptake of propidium iodide, loss of immunocytochemical staining for microtubule-associated protein 2 and staining with Fluoro-Jade B. To distinguish between necrotic vs. apoptotic neuronal cell death we used immunocytochemical staining for active caspase-3 (apoptosis indicator) and Hoechst 33342 staining of nuclear chromatin. Our experimental studies on oxygen-glucose deprivation confirmed that CA1 pyramidal cells were the most susceptible to this ischemia-like condition. Judged by propidium iodide uptake, a selective CA1 lesion, with only minor affection on CA3, occurred in cultures exposed to oxygen-glucose deprivation for 30 min. Nuclear chromatin staining by Hoechst 33342 and staining for active caspase-3 showed that oxygen-glucose deprivation induced necrotic cell death only. Addition of 10 microM of the N-methyl-D-aspartate glutamate receptor antagonist MK-801, and 20 microM of the non-N-methyl-D-aspartate glutamate receptor antagonist 2,3-dihyroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline to the culture medium confirmed that both N-methyl-D-aspartate and non-N-methyl-D-aspartate ionotropic glutamate receptors were involved in the oxygen-glucose deprivation-induced cell death. Glutamate is normally quickly removed, from the extracellular space by sodium-dependent glutamate transporters. Effects of blocking the transporters by addition of the DL-threo-beta-benzyloxyaspartate are reviewed in the last part of the paper. Under normal conditions addition of DL-threo-beta-benzyloxyaspartate in concentrations of 25 microM or more to otherwise untreated hippocampal slice cultures induced neuronal cell death, which was prevented by addition of 2,3-dihyroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline and MK-801. In energy failure situations, like cerebral ischemia and oxygen-glucose deprivation, the transporters are believed to reverse and release glutamate to the extracellular space. Blockade of the transporters by a subtoxic (10 microM) dose of DL-threo-beta-benzyloxyaspartate during oxygen-glucose deprivation (but not during the next 48 h after oxygen-glucose deprivation) significantly reduced the oxygen-glucose deprivation-induced propidium iodide uptake, suggesting a neuroprotective inhibition of reverse transporter activity by DL-threo-beta-benzyloxyaspartate during oxygen-glucose deprivation under these conditions. Adding to this, other results from our laboratory have demonstrated that pre-treatment of the slice cultures with glial cell-line derived neurotrophic factor upregulates glutamate transporters. As a logical, but in some glial cell-line derived neurotrophic factor therapy-related conditions clearly unwanted consequence the susceptibility for oxygen-glucose deprivation-induced glutamate receptor-mediated cell death is increased after glial cell-line derived neurotrophic factor treatment. In summary, we conclude that both ionotropic glutamate receptors and glutamate transporters are involved in oxygen-glucose deprivation-induced necrotic cell death in hippocampal slice cultures, which have proven to be a feasible tool in experimental studies on this topic.
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Affiliation(s)
- C Bonde
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Winslowparken 21, DK-5000 Odense, Denmark
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