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Maltsev A, Roshchin M, Bezprozvanny I, Smirnov I, Vlasova O, Balaban P, Borodinova A. Bidirectional regulation by "star forces": Ionotropic astrocyte's optical stimulation suppresses synaptic plasticity, metabotropic one strikes back. Hippocampus 2023; 33:18-36. [PMID: 36484471 DOI: 10.1002/hipo.23486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
The role of astrocytes in modulating synaptic plasticity is an important question that until recently was not addressed due to limitations of previously existing technology. In the present study, we took an advantage of optogenetics to specifically activate astrocytes in hippocampal slices in order to study effects on synaptic function. Using the AAV-based delivery strategy, we expressed the ionotropic channelrhodopsin-2 (ChR2) or the metabotropic Gq-coupled Opto-a1AR opsins specifically in hippocampal astrocytes to compare different modalities of astrocyte activation. In electrophysiological experiments, we observed a depression of basal field excitatory postsynaptic potentials (fEPSPs) in the CA1 hippocampal layer following light stimulation of astrocytic ChR2. The ChR2-mediated depression increased under simultaneous light and electrical theta-burst stimulation (TBS). Application of the type 2 purinergic receptor antagonist suramin prevented depression of basal synaptic transmission, and switched the ChR2-dependent depression into potentiation. The GABAB receptor antagonist, phaclofen, did not prevent the depression of basal fEPSPs, but switched the ChR2-dependent depression into potentiation comparable to the values for TBS in control slices. In contrast, light stimulation of Opto-a1AR expressed in astrocytes led to an increase in basal fEPSPs, as well as a potentiation of synaptic responses to TBS significantly. A specific blocker of the Gq protein downstream target, the phospholipase C, U73122, completely prevented the effects of Opto-a1AR stimulation on basal fEPSPs or Opto + TBS responses. To understand molecular basis for the observed effects, we performed an analysis of gene expression in these slices using quantitative PCR approach. We observed a significant upregulation of "immediate-early" gene expression in hippocampal slices after light activation of Opto-a1AR-expressing astrocytes alone (cRel, Arc, Fos, JunB, and Egr1) or paired with TBS (cRel, Fos, and Egr1). Activation of ChR2-expressing hippocampal astrocytes was insufficient to affect expression of these genes in our experimental conditions. Thus, we concluded that optostimulation of astrocytes with ChR2 and Opto-a1AR optogenetic tools enables bidirectional modulation of synaptic plasticity and gene expression in hippocampus.
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Affiliation(s)
- Alexander Maltsev
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Matvey Roshchin
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia.,Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
| | - Ivan Smirnov
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Olga Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Pavel Balaban
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Anastasia Borodinova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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2
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P2X7 Receptors Mediate CO-Induced Alterations in Gene Expression in Cultured Cortical Astrocytes—Transcriptomic Study. Mol Neurobiol 2018; 56:3159-3174. [DOI: 10.1007/s12035-018-1302-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/06/2018] [Indexed: 01/31/2023]
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3
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Vargas JR, Takahashi DK, Thomson KE, Wilcox KS. The expression of kainate receptor subunits in hippocampal astrocytes after experimentally induced status epilepticus. J Neuropathol Exp Neurol 2013; 72:919-32. [PMID: 24042195 PMCID: PMC3880830 DOI: 10.1097/nen.0b013e3182a4b266] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Astrocytes have emerged as active participants of synaptic transmission and are increasingly implicated in neurologic disorders including epilepsy. Adult glial fibrillary acidic protein (GFAP)-positive hippocampal astrocytes are not known for ionotropic glutamate receptor expression under basal conditions. Using a chemoconvulsive status epilepticus (SE) model of temporal lobe epilepsy, we show by immunohistochemistry and colocalization analysis that reactive hippocampal astrocytes express kainate receptor (KAR) subunits after SE. In the CA1 region, GluK1, GluK2/3, GluK4, and GluK5 subunit expression was observed in GFAP-positive astrocytes during the seizure-free or "latent" period 1 week after SE. At 8 weeks after SE, a time after SE when spontaneous behavioral seizures occur, the GluK1 and GluK5 subunits remained expressed at significant levels. Kainate receptor subunit expression was found in astrocytes in the hippocampus and surrounding cortex but not in GFAP-positive astrocytes of striatum, olfactory bulb, or brainstem. To examine hippocampal KAR expression more broadly, astroglial-enriched tissue fractions were prepared from dissected hippocampi and were found to have greater GluK4 expression after SE than controls. These results demonstrate that astrocytes begin to express KARs after seizure activity and suggest that their expression may contribute to the pathophysiology of epilepsy.
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Affiliation(s)
- Jay R. Vargas
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, Utah
| | - Daniel K. Takahashi
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah
| | - Kyle E. Thomson
- Department of Bioengineering, University of Utah, Salt Lake City, Utah
| | - Karen S. Wilcox
- Department of Pharmacology & Toxicology, University of Utah, Salt Lake City, Utah
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah
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4
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Hermann GE, Rogers RC. TNF activates astrocytes and catecholaminergic neurons in the solitary nucleus: implications for autonomic control. Brain Res 2009; 1273:72-82. [PMID: 19348788 PMCID: PMC2693276 DOI: 10.1016/j.brainres.2009.03.059] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Revised: 02/27/2009] [Accepted: 03/27/2009] [Indexed: 01/07/2023]
Abstract
Tumor necrosis factor [TNF] produces a profound anorexia associated with gastrointestinal stasis. Our work suggests that the principal site of action of TNF to cause this change in gastric function is via vagal afferents within the nucleus of the solitary tract [NST]. Excitation of these afferents presumably causes gastric stasis by activating downstream NST neurons that, in turn, suppress gastric motility via action on neurons in the dorsal motor nucleus of the vagus that project to the stomach. Results from our parallel studies on gastric vago-vagal reflexes suggest that noradrenergic neurons in the NST are particularly important to the generation of reflex gastroinhibition. Convergence of these observations led us to hypothesize that TNF action in the NST may preferentially affect putative noradrenergic neurons. The current study confirms our observations of a dose-dependent TNF activation of cells [as indicated by cFOS production] in the NST. The phenotypic identity of these TNF-activated neurons in the NST was approximately 29% tyrosine hydroxylase [TH]-positive [i.e., presumably noradrenergic neurons]. In contrast, less than 10% of the nitrergic neurons were activated after TNF exposure. Surprisingly, another 54% of the cFOS-activated cells in the NST were phenotypically identified to be astrocytes. Taken together with previous observations, the present results suggest that intense or prolonged vagal afferent activity [induced by visceral pathway activity, action of gut hormones or cytokines such as TNF] can alter local astrocyte immediate early gene expression that, in turn, can provoke long-term, perhaps permanent changes in the sensitivity of vagal-reflex circuitry.
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Affiliation(s)
- Gerlinda E Hermann
- Laboratory of Autonomic Nervous System, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA.
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5
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Metabotropic Glutamate Receptors in Glial Cells. Neurochem Res 2008; 33:2436-43. [DOI: 10.1007/s11064-008-9694-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Accepted: 04/01/2008] [Indexed: 12/29/2022]
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6
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Knapska E, Radwanska K, Werka T, Kaczmarek L. Functional internal complexity of amygdala: focus on gene activity mapping after behavioral training and drugs of abuse. Physiol Rev 2007; 87:1113-73. [PMID: 17928582 DOI: 10.1152/physrev.00037.2006] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The amygdala is a heterogeneous brain structure implicated in processing of emotions and storing the emotional aspects of memories. Gene activity markers such as c-Fos have been shown to reflect both neuronal activation and neuronal plasticity. Herein, we analyze the expression patterns of gene activity markers in the amygdala in response to either behavioral training or treatment with drugs of abuse and then we confront the results with data on other approaches to internal complexity of the amygdala. c-Fos has been the most often studied in the amygdala, showing specific expression patterns in response to various treatments, most probably reflecting functional specializations among amygdala subdivisions. In the basolateral amygdala, c-Fos expression appears to be consistent with the proposed role of this nucleus in a plasticity of the current stimulus-value associations. Within the medial part of the central amygdala, c-Fos correlates with acquisition of alimentary/gustatory behaviors. On the other hand, in the lateral subdivision of the central amygdala, c-Fos expression relates to attention and vigilance. In the medial amygdala, c-Fos appears to be evoked by emotional novelty of the experimental situation. The data on the other major subdivisions of the amygdala are scarce. In conclusion, the studies on the gene activity markers, confronted with other approaches involving neuroanatomy, physiology, and the lesion method, have revealed novel aspects of the amygdala, especially pointing to functional heterogeneity of this brain region that does not fit very well into contemporarily active debate on serial versus parallel information processing within the amygdala.
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7
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Iuvone T, Esposito G, De Filippis D, Bisogno T, Petrosino S, Scuderi C, Di Marzo V, Steardo L. Cannabinoid CB1 receptor stimulation affords neuroprotection in MPTP-induced neurotoxicity by attenuating S100B up-regulation in vitro. J Mol Med (Berl) 2007; 85:1379-92. [PMID: 17639288 DOI: 10.1007/s00109-007-0233-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 03/30/2007] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
In this study, we investigated the mechanism of S100B neurotoxicity and the effect of cannabinoids, in C6 cells treated with 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP) and co-cultured with differentiated PC12 cells. MPTP concentration- and time-dependently increased S100B density in C6 cells. This effect was followed by increased C6 cell proliferation and decreased cell viability of co-cultured PC12 cells. An antibody against S100B, given to PC12 cells before co-culture, led to their survival. Treatment with arachidonyl-2-chloroethylamide, a CB1 agonist, significantly inhibited MPTP-induced S100B density in C6 cells and protected co-cultured PC12 cells from cell death. Because MPTP selectively increased the levels of anandamide in C6 cells, the involvement of the endocannabinoid system was investigated by using selective inhibitors of endocannabinoid inactivation (cellular re-uptake or enzymatic hydrolysis) and selective cannabinoid CB1 and CB2 receptor antagonists and by silencing the CB1 receptor. Our data suggest that selective activation of CB1 receptors by either exogenous or endogenous cannabinoids might afford neuroprotection in MPTP-induced neurotoxicity also by controlling S100B up-regulation in activated glial cells.
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MESH Headings
- 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/adverse effects
- Amidohydrolases/antagonists & inhibitors
- Amidohydrolases/metabolism
- Animals
- Antibodies
- Apoptosis/drug effects
- Arachidonic Acids/metabolism
- Arachidonic Acids/pharmacology
- Calcium/metabolism
- Caspase 3/metabolism
- Cell Communication/drug effects
- Cell Differentiation
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Coculture Techniques
- Culture Media, Conditioned/metabolism
- Dose-Response Relationship, Drug
- Endocannabinoids
- Enzyme Activation
- Enzyme Inhibitors/pharmacology
- Indoles/pharmacology
- MPTP Poisoning/metabolism
- MPTP Poisoning/pathology
- Nerve Growth Factors/immunology
- Nerve Growth Factors/metabolism
- Neuroglia/drug effects
- Neuroglia/metabolism
- Neuroglia/pathology
- Neurons/drug effects
- Neurons/enzymology
- Neurons/metabolism
- Neurons/pathology
- Neuroprotective Agents/pharmacology
- PC12 Cells
- Piperidines/pharmacology
- Polyunsaturated Alkamides/metabolism
- Pyrazoles/pharmacology
- RNA Interference
- RNA, Small Interfering/metabolism
- Rats
- Receptor, Cannabinoid, CB1/drug effects
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/drug effects
- Receptor, Cannabinoid, CB2/metabolism
- Rimonabant
- S100 Calcium Binding Protein beta Subunit
- S100 Proteins/immunology
- S100 Proteins/metabolism
- Serotonin/analogs & derivatives
- Serotonin/pharmacology
- Time Factors
- Up-Regulation
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Affiliation(s)
- Teresa Iuvone
- Department of Experimental Pharmacology, Faculty of Pharmacy, University of Naples Federico II, Via D. Montesano, 49, 80131, Naples, Italy,
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8
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Sugiyama C, Nakamichi N, Ogura M, Honda E, Maeda S, Taniura H, Yoneda Y. Activator protein-1 responsive to the group II metabotropic glutamate receptor subtype in association with intracellular calcium in cultured rat cortical neurons. Neurochem Int 2007; 51:467-75. [PMID: 17559977 DOI: 10.1016/j.neuint.2007.04.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 04/12/2007] [Accepted: 04/25/2007] [Indexed: 11/28/2022]
Abstract
Activation of ionotropic glutamate (Glu) receptors, such as N-methyl-d-aspartate receptors, is shown to modulate the gene transcription mediated by the transcription factor activator protein-1 (AP1) composed of Fos and Jun family proteins in the brain, while little attention has been paid to the modulation of AP1 expression by metabotropic Glu receptors (mGluRs). In cultured rat cortical neurons, where constitutive expression was seen with all groups I, II and III mGluR subtypes, a significant and selective increase was seen in the DNA binding activity of AP1 120 min after the brief exposure to the group II mGluR agonist (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) for 5 min. In cultured rat cortical astrocytes, by contrast, a significant increase was induced by a group I mGluR agonist, but not by either a group II or III mGluR agonist. The increase by DCG-IV was significantly prevented by a group II mGluR antagonist as well as by either an intracellular Ca(2+) chelator or a voltage-sensitive Ca(2+) channel blocker, but not by an intracellular Ca(2+) store inhibitor. Moreover, DCG-IV significantly prevented the increase of cAMP formation by forskolin in cultured neurons. Western blot analysis revealed differential expression profiles of Fos family members in neurons briefly exposed to DCG-IV and NMDA. Prior or simultaneous exposure to DCG-IV led to significant protection against neuronal cell death by NMDA. These results suggest that activation of the group II mGluR subtype would modulate the gene expression mediated by AP1 through increased intracellular Ca(2+) levels in cultured rat cortical neurons.
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Affiliation(s)
- Chie Sugiyama
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School of Natural Science and Technology, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan
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9
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Mudo G, Trovato-Salinaro A, Caniglia G, Cheng Q, Condorelli DF. Cellular localization of mGluR3 and mGluR5 mRNAs in normal and injured rat brain. Brain Res 2007; 1149:1-13. [PMID: 17428452 DOI: 10.1016/j.brainres.2007.02.041] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 02/04/2007] [Accepted: 02/12/2007] [Indexed: 11/18/2022]
Abstract
In order to understand the role of metabotropic glutamate receptors (mGluRs) in the brain, it is important to know how the mGluRs are differentially expressed among the different cell types. At present, the cellular expression of mGluR3 and mGluR5 has been mostly studied in terms of proteins with observations suggesting the expression of both mGluR3 and mGluR5 in neuronal and in glial cells. In order to verify the brain cell type-expressing mGluR3 and mGluR5 mRNAs, both in normal and injured brain, we performed a double labeling analysis, by in situ hybridization for mGluR3 or mGluR5 mRNA and immunohistochemistry for specific cellular markers. This approach allowed us to find mGluR3 mRNA expressed in neurons (NeuN-positive cells), and in glial cells, such as astrocytes (GFAP-positive cells) and oligodendrocytes (CNPase-positive cells). The same analysis showed that only NeuN-positive cells express mGluR5 mRNA. The time course of mGluR3 mRNA expression in two models of hippocampal formation lesion, kainate-induced seizures or ibotenic acid injection, showed an increased expression of mGluR3 in the area of lesion. This effect appears 1 week after the injury and was localized in GFAP- and CNPase-positive cells. In contrast, mGluR5 was not found expressed in the area of lesion. The present results contribute to extend available data on cell type-expressing mGluR3 and mGluR5 in normal and injured brain and could be relevant to understand the mechanisms that drive neuron-glial cells interaction both in normal and repairing processes.
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Affiliation(s)
- Giuseppa Mudo
- Department of Experimental Medicine, Division of Human Physiology, University of Palermo, corso Tukory 129 90134 Palermo, Italy.
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10
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Radwanska K, Valjent E, Trzaskos J, Caboche J, Kaczmarek L. Regulation of cocaine-induced activator protein 1 transcription factors by the extracellular signal-regulated kinase pathway. Neuroscience 2005; 137:253-64. [PMID: 16263220 DOI: 10.1016/j.neuroscience.2005.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 08/26/2005] [Accepted: 09/03/2005] [Indexed: 10/25/2022]
Abstract
Extracellular signal-regulated kinases and activator protein 1 transcription factor have been functionally linked to addiction. It has also been shown that extracellular signal-regulated kinase activation can regulate cocaine-induced expression of c-Fos and FosB, two possible components of activator protein 1. A direct link between extracellular signal-regulated kinases and activator protein 1 activation has, however, remained unexplored. In this study, we investigated the role of extracellular signal-regulated kinases in the regulation of DNA-binding activity and composition of activator protein 1 induced in the mouse caudate putamen by cocaine treatment. We have found that pre-treatment with SL327, a selective inhibitor the extracellular signal-regulated kinase pathway, has no influence on cocaine-induced DNA-binding activity of activator protein 1, when examined one hour after an acute cocaine treatment. This phenomenon results from simultaneous decrease of c-Fos protein level and increases in JunB and deltaFosB protein levels. SL327 pre-treatment, however, reduces the DNA-binding activity of the activator protein 1 complex induced six hours after an acute cocaine treatment as well as one hour after the last of the chronic cocaine injections, a phenomenon that results from the concomitant reduction of all cocaine-induced proteins (c-Fos, FosB, deltaFosB, JunB). In conclusion, we have found that extracellular signal-regulated kinase inhibition may not only interfere with cocaine-induced gene expression and activator protein 1 complex activation, but may also disturb the time-course of gene expression and composition of activator protein 1 complex. Our results support the notion that inhibitors of the extracellular signal-regulated kinase pathway could be valuable tools to obliterate cocaine-induced molecular changes and the development of addiction.
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Affiliation(s)
- K Radwanska
- Laboratory of Molecular Neurobiology, Nencki Institute, Pasteura 3, 02 093 Warsaw, Poland
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11
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Geller SF, Stone J. Quantitative PCR analysis of FosB mRNA expression after short duration oxygen and light stress. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 533:249-57. [PMID: 15180271 DOI: 10.1007/978-1-4615-0067-4_31] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Quantitative polymerase chain reaction (QPCR) was used to examine changes in FosB mRNA expression in models of oxygen and light stress to the retina. C57BL/6 mice or Sprague-Dawley (SD) albino rats were subjected to several experimental paradigms: short-term light or oxygen stress, extended hyperoxia (75% oxygen), or a model of oxygen-induced retinopathy (OIR). Control animals were subjected to room air and 5 lux cyclic light. FosB expression dramatically increases in response to light stress as well as in a model of OIR, but not in response to sustained 75% oxygen. These data suggest that both hypoxia and light stress induce expression of FosB in the retina.
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Affiliation(s)
- Scott F Geller
- School of Optometry, University of California, Berkeley, CA 94720-2020, USA.
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12
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Méndez JA, López-Bayghen E, Rojas F, Hernández ME, Ortega A. Glutamate regulates Oct-2 DNA-binding activity through α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors in cultured chick Bergmann glia cells. J Neurochem 2004; 88:835-43. [PMID: 14756804 DOI: 10.1046/j.1471-4159.2003.02206.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ionotropic glutamate receptors in cerebellar Bergmann glial cells are linked to transcriptional regulation and, by these means, are thought to play an important role in plasticity, learning and memory and in several neuropathologies. Within the CNS, the transcription factors of the POU family bind their target DNA sequences after a growth factor-dependent phosphorylation-dephosphorylation cascade. Exposure of cultured Bergmann glial cells to glutamate leads to a time- and dose-dependent increase in Oct-2 DNA-binding activity. The use of specific pharmacological tools established the involvement of Ca2+-permeable alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors. Furthermore, the signaling cascade includes phosphatidyl inositol 3-kinase as well as protein kinase C activation. Interestingly, transcriptional as well as translational inhibitors abolish the glutamate effect, suggesting a transcriptional up-regulation of the oct-2 gene. These data demonstrate that Oct-2 expression is not restricted to neurons and further strengthen the notion that the glial glutamate receptors participate in the modulation of glutamatergic cerebellar neurotransmission.
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Affiliation(s)
- J Alfredo Méndez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del instituto Politécnico Nacional, México
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13
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Wang XS, Ong WY, Connor JR. Quinacrine attenuates increases in divalent metal transporter-1 and iron levels in the rat hippocampus, after kainate-induced neuronal injury. Neuroscience 2003; 120:21-9. [PMID: 12849737 DOI: 10.1016/s0306-4522(03)00293-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present investigation was carried out to elucidate the effect of the antimalarial drug quinacrine on levels of expression of the non-heme iron transporter, divalent metal transporter-1 (DMT1) and iron, in the hippocampus of rats after kainate treatment. The untreated hippocampus was lightly stained for DMT1, while an increase in DMT1 staining in astrocytes in the degenerating cornu ammonis (CA) fields, after kainate lesions. The increased DMT1 immunoreactivity was correlated with increased levels of Fe3+ and Fe2+ staining in the CA fields, as demonstrated by iron histochemistry (Perl's and Turnbull's blue stain for Fe3+ and Fe2+). The increases in DMT1 and iron staining were significantly attenuated by quinacrine. Rats injected with kainate and daily i.p. injections of quinacrine (5 mg/kg) for 7 days or 2 weeks showed significantly lower levels of DMT1 immunoreactivity and iron staining, compared with rats injected with kainate and saline. These results show that DMT1 expression is closely linked to iron levels, and provide further support for a crucial role that DMT1 plays in iron accumulation in the degenerating hippocampus.
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Affiliation(s)
- X S Wang
- Department of Anatomy, National University of Singapore, Singapore, 119260 Singapore
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14
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Campisi A, Caccamo D, Raciti G, Cannavò G, Macaione V, Currò M, Macaione S, Vanella A, Ientile R. Glutamate-induced increases in transglutaminase activity in primary cultures of astroglial cells. Brain Res 2003; 978:24-30. [PMID: 12834894 DOI: 10.1016/s0006-8993(03)02725-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Glutamate exposure of astroglial cells caused ligand-gated channel receptor activation, associated with excitotoxic cell response. We investigated the effects of 24 h glutamate exposure on transglutaminase in astrocytes primary cultures at 7, 14, and 21 days in vitro (DIV). Increases in enzyme activity were observed as a function of cell differentiation stage in glutamate-treated cultures. These effects were significantly reduced when GYKI 52466, an AMPA/KA receptors inhibitor, was added to the culture medium prior to incubation with glutamate. Microscopy observation on transglutaminase-mediated, fluorescent dansylcadaverine incorporation in living cells was consistent with these results. Western blotting analysis with monoclonal antibody showed that glutamate also up-regulated tissue transglutaminase expression, which reached the highest values in 14 DIV cultures. Confocal laser scanning microscopy analysis of immunostained astroglial cells showed a mainly cytoplasmic localisation of the enzyme both in control and treated cultures; nevertheless, counterstaining with the nuclear dye acridine orange demonstrated the presence of tissue transglutaminase also into the nucleus of glutamate-exposed and 21 DIV cells. The increases in enzyme expression and localisation in the nucleus of glutamate-treated astroglial cells may be part of biochemical alterations induced by excitotoxic stimulus.
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Affiliation(s)
- A Campisi
- Department of Biological Chemistry, Medical Chemistry and Molecular Biology, University of Catania, Catania, Italy
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15
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Matsui F, Kawashima S, Shuo T, Yamauchi S, Tokita Y, Aono S, Keino H, Oohira A. Transient expression of juvenile-type neurocan by reactive astrocytes in adult rat brains injured by kainate-induced seizures as well as surgical incision. Neuroscience 2002; 112:773-81. [PMID: 12088737 DOI: 10.1016/s0306-4522(02)00136-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurocan is one of the major chondroitin sulfate proteoglycans expressed in nervous tissues. The expression of neurocan is developmentally regulated, and full-length neurocan is detected in juvenile brains but not in adult brains. In the present study, we demonstrated by western blot analysis that full-length neurocan transiently appeared in adult rat hippocampus when it was lesioned by kainate-induced seizures. Immunohistochemical studies showed that neurocan was detected mainly around the CA1 region although the seizure resulted in neuronal cell degeneration in both the CA1 and CA3 regions of the hippocampus. Double-labeling for neurocan mRNA and glial fibrillary acidic protein demonstrated that many reactive astrocytes expressed neurocan mRNA. The re-expression of full-length neurocan was also observed in the surgically injured adult rat brain. In contrast, the expression of other nervous tissue chondroitin sulfate proteoglycans, such as phosphacan and neuroglycan C, was not intensified but rather was either reduced in the kainate-lesioned hippocampus or in the surgically injured cerebral cortex. These observations indicate that induction of neurocan expression by reactive astrocytes is a common phenomenon in the repair process of adult brain injury, and therefore, it can be postulated that juvenile-type neurocan plays some roles in brain repair.
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Affiliation(s)
- F Matsui
- Department of Perinatology, Institute for Developmental Research, Kasugai, Aichi 480-0392, Japan.
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16
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Yamagata K, Tagami M, Ikeda K, Tsumagari S, Yamori Y, Nara Y. Differential regulation of glial cell line-derived neurotrophic factor (GDNF) mRNA expression during hypoxia and reoxygenation in astrocytes isolated from stroke-prone spontaneously hypertensive rats. Glia 2002; 37:1-7. [PMID: 11746778 DOI: 10.1002/glia.10003] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF) plays several important roles in the survival and recovery of mature neurons during ischemia. We examined the possibility that the expression of GDNF mRNA and the release of GDNF protein are regulated differentially in cultured astrocytes from the stroke-prone spontaneously hypertensive rat (SHRSP) compared with those from Wistar Kyoto rats (WKY) during hypoxia and reoxygenation (H/R) and after exposure to glutamate and hydrogen peroxide (H(2)O(2)). The mRNA expression was quantitated by reverse transcription-polymerase chain reaction (RT-PCR) based on the fluorescent TaqMan methodology. A new instrument capable of measuring fluorescence in real-time was used to quantify gene amplification in astrocytes. GDNF protein was investigated by enzyme-linked immunosorbent assay (ELISA). GDNF mRNA expression and GDNF protein release at normoxia were greater in SHRSP than in WKY astrocytes. During H/R, however, the mRNA expression and protein release tended to be reduced in SHRSP compared with WKY. Glutamate and H(2)O(2) induced the expression of GDNF mRNA and the release of GDNF protein in both WKY and SHRSP in a dose-dependent manner. Levels of GDNF mRNA and protein in SHRSP were significantly lower than in WKY. These findings indicate that GDNF production in SHRSP astrocytes was low in response to H/R, glutamate, and H(2)O(2), compared with that observed in WKY. We conclude that the attenuated production of GDNF in astrocytes is involved in neuronal vulnerability in SHRSP during H/R, as GDNF production, which is stimulated by glutamate and H(2)O(2), is closely related to the protective effect against H/R-mediated neurotoxicity.
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Affiliation(s)
- Kazuo Yamagata
- Division of Life Science, Graduate School of Integrated Science and Art, University of East Asia, Yamaguchi, Japan.
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17
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Seifert G, Steinhäuser C. Ionotropic glutamate receptors in astrocytes. PROGRESS IN BRAIN RESEARCH 2001; 132:287-99. [PMID: 11544996 DOI: 10.1016/s0079-6123(01)32083-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- G Seifert
- Department of Neurosurgery, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
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18
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Elezgarai I, Bilbao A, Mateos JM, Azkue JJ, Benítez R, Osorio A, Díez J, Puente N, Doñate-Oliver F, Grandes P. Group II metabotropic glutamate receptors are differentially expressed in the medial nucleus of the trapezoid body in the developing and adult rat. Neuroscience 2001; 104:487-98. [PMID: 11377849 DOI: 10.1016/s0306-4522(01)00080-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The existence of a neuronal-glial signalling through the activation of neurotransmitter receptors expressed in glia is well-documented. In excitatory synapses, glutamate released from presynaptic terminals activates not only postsynaptic receptors, but also ionotropic and metabotropic glutamate receptors localized in the glia ensheathing the synapses. The medial nucleus of the trapezoid body of the auditory system is involved in the localization of sounds in the space. In this nucleus, the large excitatory synaptic terminals formed by the calyces of Held on the principal globular cell bodies are wrapped by astrocytic processes. Since these synapses are functional from early postnatal days, glia receiving excitatory synaptic signals from the calyces may participate in modulating the maturation and development of the system. Groups I and II of metabotropic glutamate receptors (mGluRs) have been localized in glial cells in different brain regions. To investigate whether group II mGluRs are present in the medial nucleus of the trapezoid body, we have studied the pattern of expression of mGluR2/3 in the developing and mature nucleus by means of immunocytochemichal methods. The most remarkable finding was the switch in the occurrence of mGluR2/3 from glial to neuronal compartments. Thus, a preferential localization of mGluR2/3 immunoreactivity was observed in astrocytic processes surrounding the calyces of Held during the early postnatal development. In contrast, the main feature in adult rats was the presence of the group II mGluRs in presynaptic calyces of Held and postsynaptic principal globular cells.From these observations we suggest a role for group II mGluRs in neuronal-glial signalling in the calyx of Held-principal globular neuron synapses. Activation of these receptors might be relevant to the maturation and modulation of synaptic transmission in the medial nucleus of the trapezoid body.
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Affiliation(s)
- I Elezgarai
- Department of Neurosciences, Faculty of Medicine and Dentistry, Basque Country University, 699-48080, Bilbao, Spain
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19
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Abstract
Functional and molecular analysis of glial voltage- and ligand-gated ion channels underwent tremendous boost over the last 15 years. The traditional image of the glial cell as a passive, structural element of the nervous system was transformed into the concept of a plastic cell, capable of expressing a large variety of ion channels and neurotransmitter receptors. These molecules might enable glial cells to sense neuronal activity and to integrate it within glial networks, e.g., by means of spreading calcium waves. In this review we shall give a comprehensive summary of the main functional properties of ion channels and ionotropic receptors expressed by macroglial cells, i.e., by astrocytes, oligodendrocytes and Schwann cells. In particular we will discuss in detail glial sodium, potassium and anion channels, as well as glutamate, GABA and ATP activated ionotropic receptors. A majority of available data was obtained from primary cell culture, these results have been compared with corresponding studies that used acute tissue slices or freshly isolated cells. In view of these data, an active glial participation in information processing seems increasingly likely and a physiological role for some of the glial channels and receptors is gradually emerging.
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Affiliation(s)
- A Verkhratsky
- School of Biological Sciences, The University of Manchester, Oxford Road, Manchester, UK.
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20
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Condorelli DF, Conti F, Gallo V, Kirchhoff F, Seifert G, Steinhäuser C, Verkhratsky A, Yuan X. Expression and functional analysis of glutamate receptors in glial cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 468:49-67. [PMID: 10635019 DOI: 10.1007/978-1-4615-4685-6_5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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21
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Toms NJ, Roberts PJ. Group 1 mGlu receptors elevate [Ca2+]i in rat cultured cortical type 2 astrocytes: [Ca2+]i synergy with adenosine A1 receptors. Neuropharmacology 1999; 38:1511-7. [PMID: 10530813 DOI: 10.1016/s0028-3908(99)00090-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Brain macroglia are known to express a diverse array of neurotransmitter receptors whose signal transduction pathways may be subject to heteroreceptor 'cross-talk'. In the current study we have examined group 1 mGlu receptor-evoked [Ca2+]i signalling, and possible heteroreceptor cross-talk, in cultured type 2 astrocytes. The selective group 1 metabotropic glutamate (mGlu) receptor agonist (S)-3,5-dihydroxyphenylglycine (DHPG) elevated [Ca2+]i (EC50 = 1.7 +/- 0.6 microM); an effect reversed by the selective mGlu receptor antagonist (S)-alpha-methyl-4-carboxyphenylglycine (IC50 = 52.7 +/- 8.7 microM). DHPG-evoked [Ca2+]i responses were abolished by (1) thapsigargin (100 nM), implicating the involvement of internal Ca2+ stores in group 1 mGlu [Ca2+]i responses and (2) the removal of extracellular Ca2+. When applied alone, the selective adenosine A1 receptor agonist, N6-cyclopentyladenosine (CPA, 100 nM) failed to influence [Ca2+]i. However, in the presence of 1 microM DHPG, CPA potently (EC50 = 12.3 +/- 1.9 nM) increased [Ca2+]i responses. In the presence of 100 nM CPA, the efficacy of DHPG was doubled without any significant change in the DHPG EC50 value. This effect was reversed by either the selective adenosine A1 receptor antagonist, 8-cyclopentyltheophylline (IC50 = 50.3 +/- 19.9 nM) or overnight incubation with Pertussis toxin (100 ng/ml). We conclude that (1) type 2 astrocytes contain group 1 mGlu receptors coupled to [Ca2+]i signalling and (2) co-activation of adenosine A1 receptors enhances group 1 mGlu-evoked [Ca2+]i responses in these cells via a Gi/o G protein-mediated mechanism.
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Affiliation(s)
- N J Toms
- Department of Pharmacology, School of Medical Sciences, University of Bristol, UK
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22
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Biber K, Laurie DJ, Berthele A, Sommer B, Tölle TR, Gebicke-Härter PJ, van Calker D, Boddeke HW. Expression and signaling of group I metabotropic glutamate receptors in astrocytes and microglia. J Neurochem 1999; 72:1671-80. [PMID: 10098876 DOI: 10.1046/j.1471-4159.1999.721671.x] [Citation(s) in RCA: 171] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stimulation of astrocytes with the excitatory neurotransmitter glutamate leads to the formation of inositol 1,4,5-trisphosphate and the subsequent increase of intracellular calcium content. Astrocytes express both ionotropic receptors and metabotropic glutamate (mGlu) receptors, of which mGlu5 receptors are probably involved in glutamate-induced calcium signaling. The mGlu5 receptor occurs as two splice variants, mGlu5a and mGlu5b, but it was hitherto unknown which splice variant is responsible for the glutamate-induced effects in astrocytes. We report here that both mRNAs encoding mGlu5 receptor splice variants are expressed by cultured astrocytes. The expression of mGlu5a receptor mRNA is much stronger than that of mGlu5b receptor mRNA in these cells. In situ hybridization experiments reveal neuronal expression of mGlu5b receptor mRNA in adult rat forebrain but a strong neuronal expression of mGlu5a mRNA only in olfactory bulb. Signals for mGlu5a receptor mRNA in the rest of the brain were diffuse and weak but consistently above background. Activation of mGlu5 receptors in astrocytes yields increases in inositol phosphate production and transient calcium responses. It is surprising that the rank order of agonist potency [quisqualate > (2S,1 'S,2'S)-2-(carboxycyclopropyl)glycine = trans-(1S,3R)-1-amino-1,3-cyclopentanedicarboxylic acid (1S,3R-ACPD) > glutamate] differs from that reported for recombinantly expressed mGlu5a receptors. The expression of mGlu5a receptor mRNA and the occurrence of 1S,3R-ACPD-induced calcium signaling were found also in cultured microglia, indicating for the first time expression of mGlu5a receptors in these macrophage-like cells.
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Affiliation(s)
- K Biber
- Institute for Medical Physiology, University of Groningen, The Netherlands
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23
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Yagle K, Costa LG. Effects of Alcohol on Immediate-Early Gene Expression in Primary Cultures of Rat Cortical Astrocytes. Alcohol Clin Exp Res 1999. [DOI: 10.1111/j.1530-0277.1999.tb04136.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Abstract
Astrocytes closely contact neurons where they respond to neuronally released glutamate in immature brain slices. In previous studies, neither metabotropic nor ionotropic glutamate receptor-mediated responses were detected by imaging Ca2+ in astrocytes from mature (P21-P42) animals, suggesting astrocyte glutamate receptors only contribute to hippocampus physiology during development. In contrast to Ca2+ imaging, published electrophysiological experiments suggest P30-P35 astrocytes have alpha-amino-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. For this study, we imaged astrocytes in P31-P38 hippocampal slices to determine if metabotropic and ionotropic glutamate receptor activation elevates intracellular calcium in mature astrocytes. Drugs were perfused while [Ca2+]i was monitored (confocal imaging) in cells loaded with Calcium Green 1-AM. Imaged cells were subsequently identified as astrocytes by GFAP/S-100 immunostaining. Astrocytic Ca2+ increased after glutamate application in the presence of a glutamate uptake inhibitor. An agonist at group I/II metabotropic glutamate receptors, (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD), elicited Ca2+ increases as did group I agonist 3,5-dihydroxyphenylglycine (DHPG), suggesting that mature astrocytes respond to glutamate via metabotropic glutamate receptors. AMPA also elicited Ca2+ elevations that were inhibited by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and occurred after treatment with omega-conotoxin MVIIC to block neurotransmitter release. These results demonstrate that astrocytes in mature hippocampus have functional ionotropic and metabotropic glutamate receptors that regulate astrocytic calcium levels. Glutamatergic regulation of astrocytic [Ca2+]i may be involved in synapse modeling, long-term potentiation, excitotoxicity and other events dependent on glutamatergic transmission in adult hippocampus.
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Affiliation(s)
- M K Shelton
- Department of Pharmacology, University of North Carolina, Chapel Hill 27599, USA
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25
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López T, López-Colomé AM, Ortega A. Changes in GluR4 expression induced by metabotropic receptor activation in radial glia cultures. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 58:40-6. [PMID: 9685580 DOI: 10.1016/s0169-328x(98)00094-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The expression of neurotransmitter receptors in glial cells has suggested a regulatory role of these cells in synaptic function. In radial glia, glutamate receptors elicit a cascade from the membrane to the nucleus and a consequent change in gene expression. In order to gain insight into this process, we address the question of whether receptor activation leads to changes in the repertoire of AMPA/KA glutamate receptor subunits in Bergmann and Müller glial cells. Of the subunits investigated, only GluR4 was up-regulated in Bergmann glial cells both at mRNA and protein levels. In contrast, in Müller glial cells Glu treatment leads to a reduction in GluR4 mRNA and protein expression. Both effects are receptor-mediated and must probably involve group I of metabotropic glutamate receptors. Accordingly, using Northern blot analysis and RT-PCR we detected the expression of both mGluR1 and mGluR5 transcripts in the cultured cells. Our results confirm that glutamate receptors in Bergmann and Müller cells modulate gene expression and further strengthen a plausible role of glial cells in long-lasting changes in the central nervous system.
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Affiliation(s)
- T López
- Departamento de Genética y Biología Molecular, CINVESTAV-IPN, Apartado Postal 14-740, México D.F. 07000, Mexico
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26
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Labrakakis C, Patt S, Hartmann J, Kettenmann H. Glutamate receptor activation can trigger electrical activity in human glioma cells. Eur J Neurosci 1998; 10:2153-62. [PMID: 9753101 DOI: 10.1046/j.1460-9568.1998.00226.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cells from major types of gliomas, i.e. oligodendrogliomas and glioblastomas, are able to generate action potentials upon a current injection similar to neurons (Patt et al. (1996) Neuroscience, 71, 601-611; Labrakakis et al. (1997b) J. Neuropath. Exp. Neurol., 56, 243-254. Here, we report that activation of ionotropic glutamate receptors by the selective agonist, kainate, or by glutamate itself, depolarized the tumour cells in culture and living slices from tumour tissue, and can elicit volleys of action potentials, as recorded with the patch-clamp technique. Sixty-six percent of the glioblastoma cells, 44% of the astocytoma and 86% of the oligodendroglioma cells responded to glutamate and the specific agonist of AMPA/kainate receptors, kainate. The involvement of non-NMDA (N-methyl-D-aspartate) receptors is further supported by the observation that both kainate and glutamate currents were blocked by CNQX (6-cyano-7-nitroquinoxaline-2,3-dione). The receptor activation was accompanied by an increase in cytosolic Ca2+, as recorded with a fura-2 microfluorometric system. The Ca2+ elevation was mediated by the activation of Ca2+ channels due to membrane depolarization. The presence of voltage-gated Ca2+ channels was confirmed by patch-clamp experiments. Taken together, these findings imply that the electrophysiological properties of glioma cells are more reminiscent of those of neurons than of glial cells.
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Affiliation(s)
- C Labrakakis
- Department of Cellular Neurosciences, Max Delbrück Center for Molecular Medicine, Berlin, Germany
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27
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Abstract
GFAP(+) cells were acutely isolated from the hippocampi of 1-10 day old rats, and the intracellular calcium responses to L-glutamate, ATP, and 5-HT were studied in single cells. Eighty-two percent of such cells responded to glutamate, 20% of them responded to ATP, and none responded to 5-HT. The same cells that failed to respond to ATP and 5-HT often responded to glutamate. These proportions of cells responding to glutamate and ATP are very similar to those reported for GFAP(+) astrocytes in hippocampal slices (Porter and McCarthy, 1995a,b). After culturing for 1-2 days in serum-containing medium, 60% of such acutely isolated cells responded to either glutamate or ATP, and 5% to 5-HT. After 1 week in culture, the percentage of cells responding to glutamate remained essentially the same (62%) but the percentages of cells responding to ATP and 5-HT increased to 92% and 62%, respectively. These percentages were very close to the results obtained from primary hippocampal astrocyte cultures prepared from 1 day old rats and cultured for 1-2 weeks in vitro. Pharmacological characterization showed that the Ca2+ responses of acutely isolated hippocampal astrocytes from P1-10 rats was due to activation of a group I metabotropic glutamate receptor. The calcium responses to ATP and 5-HT in acutely isolated cells that were then cultured were mediated by P2y and 5-HT2A receptors, respectively. These data show that, like cortical astrocytes (Kimelberg et al., 1997), GFAP(+) astrocytes cultured from the hippocampi of young rats showed marked differences in receptor expression compared to their acutely isolated counterparts. Also, since the astrocytes acutely isolated from these 2 different brain regions showed qualitatively the same responses for the 3 receptors selected, it indicates a degree of homogeneity of receptor expression for astrocytes from these 2 brain regions.
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Affiliation(s)
- Z Cai
- Department of Pharmacology and Neuroscience, Albany Medical College, New York 12208, USA
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28
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Condorelli DF, Dell'Albani P, Corsaro M, Giuffrida R, Caruso A, Trovato Salinaro A, Spinella F, Nicoletti F, Albanese V, Giuffrida Stella AM. Metabotropic glutamate receptor expression in cultured rat astrocytes and human gliomas. Neurochem Res 1997; 22:1127-33. [PMID: 9251103 DOI: 10.1023/a:1027317319166] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In order to confirm the existence of metabotropic glutamate receptors in astroglial cultures and to provide information on different receptor subtypes, the expression of different mGluRs was analysed in cultures highly enriched in rat astroglial cells. mRNA levels for mGluR1, 2, 3, 4, 7 were undetectable by Northern blot analysis in primary type-1 astroglial cultures derived from total cerebral hemispheres, cerebral cortex and striatum. Interestingly, these cultures expressed a low, but detectable, level of mGluR5 mRNA. The more sensitive technique Reverse Transcription-Polymerase Chain Reaction (RT-PCR) confirmed the presence of mGluR5 transcript in cultured astrocytes and, in addition, revealed the presence of mGluR3 mRNA. The lack of expression of mGluR5 in CG-4 cells, a rat cell line able to differentiate in type-2 astrocytes or oligodendrocytes depending on the culture conditions, suggested that the presence of mGluR5 was not a general feature of cells of glial origin. Moreover, all the examined mGluR transcript were undetectable by RT-PCR in CG4 cells. In order to confirm the possible expression of mGluR5 in cell of glial origin we examined the mRNA levels for this receptor in tissue samples from human gliomas obtained after surgical resection of the tumors: only 1 sample (grade II astrocytoma), out of 8 examined, showed the presence of mGluR5 mRNA. In conclusion our data show that the only cloned metabotropic receptor linked to phosphoinositide hydrolysis, whose expression is detectable in cultured type-1 astrocytes, in mGluR5. It remains to be established if the low level of expression of mGluR3 could be responsible for the group II metabotropic glutamate receptor activity previously observed in cultured astroglial cells.
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Affiliation(s)
- D F Condorelli
- Institute of Biochemistry, School of Medicine, University of Catania, Italy
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29
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Seifert G, Rehn L, Weber M, Steinhäuser C. AMPA receptor subunits expressed by single astrocytes in the juvenile mouse hippocampus. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1997; 47:286-94. [PMID: 9221927 DOI: 10.1016/s0169-328x(97)00059-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The subunit composition of native AMPA receptor (AMPA-R) channels was recently described in several neuronal cell types but less information is available on glial cells. Evidence from recombinant receptor studies suggests that the expression of distinct subunits determines the specific functional properties of the receptor channel. In the present study, we combined the patch clamp technique with the reverse transcription-polymerase chain reaction (RT-PCR) to correlate the expression of gene transcripts with functional properties of AMPA-R in single identified glial cells of the hippocampus. The cells were freshly isolated from the stratum radiatum of the CA1 subregion. We focused on cells expressing AMPA-R with an intermediate Ca2+ permeability which were identified as immature astrocytes due to their morphological, immunocytochemical and electrophysiological characteristics. After recording, the cells were harvested and RT-PCR was performed with the same individual cell to investigate the composition of their AMPA-R transcripts. Our results suggest the expression of a heteromeric subunit architecture. In all cells, the GluR2 subunit was present, which is known to confer a low Ca2+ permeability to the receptor complex. Most frequently, we met co-expression of GluR2 and GluR4. This study demonstrates that astrocytes in the hippocampus express a distinct AMPA-R subunit composition which differs from neurons. The glial receptors might be involved in the modulation of gene expression as well as the regulation of proliferation and differentiation.
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Affiliation(s)
- G Seifert
- Institute of Physiology, Department of Neurophysiology, Friedrich-Schiller University Jena, Germany
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30
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Chisamore B, Solc M, Dow K. Excitatory amino acid regulation of astrocyte proteoglycans. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1996; 97:22-8. [PMID: 8946051 DOI: 10.1016/s0165-3806(96)00129-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Activity-dependent enduring change in cellular communication is essential for specific connectivity during development of the nervous system and for adaptive responses of the mature nervous system. Here we report that glutamate activation of excitatory amino acid receptors induces the synthesis and release of proteoglycans (PGs) from fetal hippocampal-astrocytes in dissociated culture. PG synthesis and release are mediated via kainate and metabotropic receptor activation. Glutamate exposure did not regulate the release of a specific family of PG, but glutamate inhibited the synthesis of heparan sulfate (HS) PGs that appeared within the extracellular environment of the astrocyte. Particulate protein kinase C (PKC) activity was increased by glutamate and the PKC activator phorbol 10-myristate 13-acetate produced a dose-dependent increase in PG release. However, glutamate-induced PG release was not blocked by inhibition of PKC activity. These data suggest that PKC activation can lead to PG release, but is not necessary for it. Activity-dependent influences on a class of substrate-bound molecular species with growth-modulatory properties may be involved in spatial regulation of neuronal growth responses produced by excitatory amino acids.
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Affiliation(s)
- B Chisamore
- Department of Pediatrics, Kingston General Hospital, Queen's University, Canada
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31
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Yano S, Fukunaga K, Takiguchi M, Ushio Y, Mori M, Miyamoto E. Regulation of CCAAT/enhancer-binding protein family members by stimulation of glutamate receptors in cultured rat cortical astrocytes. J Biol Chem 1996; 271:23520-7. [PMID: 8798561 DOI: 10.1074/jbc.271.38.23520] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Regulation of mRNA levels, DNA binding activities, and phosphorylation of CCAAT/enhancer-binding protein (C/EBP) family members by stimulation of glutamate receptors were studied in cultured rat cortical astrocytes. Indirect immunofluorescence and immunoblot analyses with specific antibodies to C/EBP family members revealed that both C/EBPbeta and C/EBPdelta but not C/EBPalpha are expressed in the nuclei of astrocytes. After exposure to glutamate, C/EBPbeta mRNA levels increased within 10 min, reached the maximal level at about 1 h, and returned to the basal level within 6 h. In contrast, C/EBPdelta mRNA levels decreased by 6 h and were recovered within 12 h. These changes in mRNA levels were accompanied by an increase and a decrease in proteins for C/EBPbeta and C/EBPdelta, respectively. Elevation of C/EBPbeta mRNA levels by glutamate treatment required an increase in intracellular Ca2+ concentration and depended on activations of protein kinase C and calmodulin-dependent protein kinases. Gel mobility shift analysis using nuclear extracts from the glutamate-treated cells showed increases in C/EBP site binding activities 2 h after the exposure to glutamate. Moreover, glutamate stimulated phosphorylation of C/EBPbeta in 32P-labeled astrocytes in a Ca2+-dependent manner. These results suggest that glutamate regulates functions of C/EBP family members in brain astrocytes through changes in mRNA levels of C/EBPbeta and C/EBPdelta as well as through phosphorylation of C/EBPbeta.
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Affiliation(s)
- S Yano
- Department of Pharmacology, Kumamoto University School of Medicine, Kumamoto 860, Japan
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32
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Abstract
Glutamate (Glu) receptors convey most of the excitatory synaptic transmission in the mammalian CNS. Distinct Glu-receptor genes and different subtypes of glutamate-activated channels are expressed ubiquitously throughout the developing and mature brain in the two major macroglial cell types, astrocytes and oligodendrocytes. These glial receptors are found in acutely isolated cells and in brain slices, and are therefore functional in vivo. Glutamate receptors in glial cells are activated during neuronal activity, and their activation modulates gene expression in astrocytes and oligodendrocytes. The proliferation and differentiation of glial precursor cells are also regulated by activation of Glu receptors, suggesting that the excitatory transmitter might be one of the environmental signals that regulate glial-cell development.
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Affiliation(s)
- C Steinhäuser
- Abteilung Neurophysiologie, Friedrich-Schiller Universität Jena, Germany
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33
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Liu HN, Almazan G. Glutamate induces c-fos proto-oncogene expression and inhibits proliferation in oligodendrocyte progenitors: receptor characterization. Eur J Neurosci 1995; 7:2355-63. [PMID: 8845939 DOI: 10.1111/j.1460-9568.1995.tb01032.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of glutamate on c-fos expression in oligodendrocyte progenitors was investigated by Northern blot analysis. Glutamate caused rapid and transient induction. Both 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), two competitive non-NMDA ionotropic receptor antagonists, reduced glutamate-induced c-fos expression, whereas the NMDA antagonist MK-801 was ineffective. In addition, the glutamate receptor agonists (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrobromide (AMPA) and kainate strongly induced c-fos. However, the metabotropic receptor agonist trans-(+/-)-1-amino-(1S,3R)-cyclopentanedicarboxylic acid (trans-(+/-)-ACPD) did not increase c-fos mRNA level and the antagonist L-(+)-2-amino-3-phosphonopropionic acid did not block glutamate-induced c-fos mRNA. These findings indicate that c-fos induction in oligodendrocyte progenitors is mediated through the AMPA/kainate receptors, while NMDA and metabotropic receptor subtypes are not involved. Chelation of extracellular calcium by EDTA prevented glutamate-induced c-fos expression. Similarly, the protein kinase C inhibitor 1-(5-isoquinoline-sulphonyl)-2-methylpiperazine dihydrochloride (H7) and down-regulation of protein kinase C by prolonged exposure to phorbol-12-myristate 13-acetate blocked c-fos induction. These results suggest that induction of c-fos through AMPA/kainate receptors is dependent on extracellular calcium influx and involves downstream activation of phorbol ester-sensitive protein kinase C. The effect of glutamate on oligodendrocyte progenitor proliferation was assessed by [3H]thymidine incorporation. Glutamate and the agonists kainate and AMPA, but not trans-(+/-)-ACPD, caused a dose-dependent decrease in [3H]thymidine incorporation. All these pharmacological agents were not toxic to oligodendrocyte progenitors. CNQX reversed the inhibitory effects produced by glutamate and the various agonists. These results suggest that glutamate may modulate the growth and differentiation of oligodendrocytes in the central nervous system.
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Affiliation(s)
- H N Liu
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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Condorelli DF, Salin T, Dell' Albani P, Mudo G, Corsaro M, Timmusk T, Metsis M, Belluardo N. Neurotrophins and their trk receptors in cultured cells of the glial lineage and in white matter of the central nervous system. J Mol Neurosci 1995; 6:237-48. [PMID: 8860235 DOI: 10.1007/bf02736783] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous studies have analyzed the expression of different members of the neurotrophin family and their trk receptors in glial cultures composed mainly or exclusively of type-1 astrocytes, whereas only partial data have been published on other cultured glial types. In this article we compare the mRNA levels for neurotrophins (NGF, BDNF, NT-3, NT-4) and their high-affinity receptors (trkA, trkB, trkC) in cultures enriched in specific glial types, such as microglia, type-1 astroglia, and cells of the O/2A lineage (type-2 astroglia and oligodendroglia). Relatively high levels of NGF mRNA (comparable to those observed in adult rat cerebral cortex) are present in all types of cultured glial cells, except for a low level of expression in cultures enriched in microglial cells. In contrast, BDNF mRNA is undetectable in all cultures examined. NT-3 and NT-4 mRNA molecules, at a level equal to that observed in adult rat cerebral cortex, are easily detected in type-1 astrocyte cultures, whereas their hybridization signals are undetectable in cells of the O/2A lineage and in microglial cultures. The analysis of neurotrophin receptor mRNAs confirms the absence of trkA mRNA, the presence of relatively high levels of trkB mRNA (70-100% of cerebral cortex values), and low levels of trkC mRNA (10-18% of cerebral cortex values) in both cultured astroglial and oligodendroglial cells. Only very low levels of trkB and trkC mRNAs are observed in microglial cultures. Although cultured glial cells express mainly mRNAs encoding for the truncated form of trkB and trkC, a low level of mRNA encoding for the full-length catalytic form of these receptors is detected by the sensitive ribonuclease protection assay.
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Gallo V, Russell JT. Excitatory amino acid receptors in glia: different subtypes for distinct functions? J Neurosci Res 1995; 42:1-8. [PMID: 8531218 DOI: 10.1002/jnr.490420102] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
It is now well established that expression of voltage- and ligand-gated ionic channels, as well as G protein-coupled receptors, is not a property unique to neurons, but is also shared by macroglial cells (astrocytes and oligodendrocytes). These glial cells can receive a variety of signals from neurons at different stages of their development. Activation of membrane receptors may affect glial cell activity, proliferation, maturation, and survival through a complex cascade of intracellular events leading to long-term changes in glial cell phenotype and functional organization. Here we review the experimental evidence for glutamate receptor expression in glial cells in culture and in situ, and the molecular and functional properties of these receptors. We also describe some experimental models that identify possible functions of glutamate receptors in glia. Now that the existence of glutamate receptors in glia has been unambiguously demonstrated, future research will have to 1) determine which receptor subtypes are expressed in macroglial cells in vivo; 2) analyze, in adequate experimental models, the short- and long-term changes produced by glutamate receptor activation in glia; and 3) establish whether these receptors play a role in neuron-glia communication in the brain.
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Affiliation(s)
- V Gallo
- Laboratory of Cellular and Molecular Neurophysiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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36
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López-Colomé AM, Murbartián J, Ortega A. Excitatory amino acid-induced AP-1 DNA binding activity in Müller glia. J Neurosci Res 1995; 41:179-84. [PMID: 7650753 DOI: 10.1002/jnr.490410205] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effect of L-glutamate (L-Glu) and its structural analogs N-methyl-D-aspartate (NMDA), quisqualate (QA), and kainate (KA) on the DNA binding activity of the Activator Protein 1 (AP-1) and the Ca2+/cAMP Responsive Element Binding Protein (CREB) families of transcription factors was examined in cultured chick retinal Müller glia cells. L-Glu, NMDA, and KA evoked a dose and time dependent increase in AP-1 DNA binding activity and had no effect on CREB binding. The order of potency for stimulating AP-1 DNA binding was NMDA > or = Glu > KA >> QA. L-Glu responses were partially blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and by 3-[RS)-2-carboxypiperazin-4-yl)]-propyl-1-phosphonate (CPP) indicating that the increase in DNA binding is mediated both by an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/low affinity KA and a NMDA subtypes of L-Glu receptors. Since Müller glia L-Glu receptors are probably mediators of the efficacy of the excitatory transmission in the retina, the present findings suggest that a stimulus-transcription coupling triggered by L-Glu in the glial cells might have a role in the long-term modulation of these synapses.
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37
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Smith TL, Bitrick MS. Lack of involvement of protein kinase C in ethanol-induced inhibition of metabotropic-glutamate receptor function in primary cultures of astrocytes. Life Sci 1995; 56:PL485-9. [PMID: 7540711 DOI: 10.1016/0024-3205(95)00236-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The stimulation of [3H] inositol phosphate (InP) formation by the selective metabotropic-glutamate receptor agonist, 1S, 3R-ACPD, was significantly reduced in rat cortical astrocytes chronically exposed to 100 mM ethanol for 4 days. Under the same conditions, chronic ethanol either increased or did not affect the InP responses to norepinephrine and carbachol, respectively. The InP responses to all three agonists were sensitive to phorbol 12-myristate 13-acetate. Although the protein kinase C inhibitors, calphostin C and staurosporine, significantly relieved the ethanol induced inhibtion of the InP response to 1S, 3R-ACPD, these responses were still significantly less than corresponding values obtained from control cells treated with these inhibitors. The data suggests that mechanisms in addition to protein kinase C are responsible for the ethanol induced inhibition of metabotropic-glutamate function.
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Affiliation(s)
- T L Smith
- Department of Veterans Affairs Medical Center, Tucson, AZ 85723, USA
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Gallo V, Pende M, Scherer S, Molné M, Wright P. Expression and regulation of kainate and AMPA receptors in uncommitted and committed neural progenitors. Neurochem Res 1995; 20:549-60. [PMID: 7643960 DOI: 10.1007/bf01694536] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Here we review experimental evidence of non-NMDA glutamate receptor expression in the embryonic central nervous system. AMPA- and kainate-preferring glutamate receptor subunit mRNA transcripts are detected in embryonic neurons, glia and neural progenitors. Functional assays demonstrate that in some cell subpopulations ionotropic glutamate receptors are expressed by progenitors before synapse formation and terminal differentiation, and may be present before lineage determination is specified. The activation of these receptors triggers induction of immediate early gene transcription in progenitor cells. The cloning and transcriptional analysis of upstream regulatory regions of glutamate receptor genes governing their temporal and tissue-specific expression are also discussed.
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Affiliation(s)
- V Gallo
- Unit on Neurobiology, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland 20892, USA
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39
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Copani A, Bruno V, Dell'Albani P, Battaglia G, Barresi V, Caruso A, Nicoletti F, Condorelli DF. Growth conditions differentially affect the constitutive expression of primary response genes in cultured cerebellar granule cells. Neurochem Res 1995; 20:611-6. [PMID: 7643967 DOI: 10.1007/bf01694544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cultured cerebellar granule cells underwent apoptotic degeneration when grown in medium containing 10 instead of 25 mM K+. Knowing that apoptosis is associated with changes in the expression of primary response genes, we have measured c-fos, zif/268, and c-jun mRNA levels during maturation of cultured granule cells grown in 10 or 25 mM K+. The constitutive expression of c-fos and zif/268 was differentially regulated by extracellular K+ concentration at 5 days of maturation in vitro (DIV), when cells grown under suboptimal conditions (i.e. in 10 mM K+) are committed to degenerate. At this stage, c-fos mRNA levels were detectable only in cultures grown in 25 mM K+, whereas zif/268 mRNA levels were dramatically elevated in cultures grown in 10 mM K+. This provides one of the few conditions in which c-fos and zif/268 are differentially regulated in nerve cells. Substantial changes in c-jun, or beta-actin mRNA levels were detectable only at 7 DIV, when the percentage of apoptotic cells had already reached a plateau in cultures grown in 10 mM K+. We speculate that changes in the expression of zif/268 are important in the gene program associated with the induction of apoptosis by trophic deprivation in cultured neurons.
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Affiliation(s)
- A Copani
- Institute of Pharmacology, School of Medicine, University of Catania, Italy
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40
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Zabłocka B, Lukasiuk K, Lazarewicz JW, Domańska-Janik K. Modulation of ischemic signal by antagonists of N-methyl-D-aspartate, nitric oxide synthase, and platelet-activating factor in gerbil hippocampus. J Neurosci Res 1995; 40:233-40. [PMID: 7745616 DOI: 10.1002/jnr.490400212] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cerebral ischemia in the gerbil results in early hippocampal changes, which include transient activation and/or translocation of protein kinase C (PKC), increased enzymatic activity of ornithine decarboxylase (ODC), and elevated DNA binding ability of activator protein-1 (AP1). The time-course of all three of these postischemic responses was found to be almost parallel, peaking at 3 hr after the ischemic insult. The effectiveness of known modulators of postischemic morphological outcome (MK-801, L-NAME, and gingkolides BN 52020 and BN 52021) in counteracting the induction of PKC, ODC, and AP1 formation was tested. These drugs were administrated as followed: MK-801 (a noncompetitive inhibitor of NMDA channel), 0.8 mg/kg i.p., 30 min before ischemia, and 5 min after the insult; L-NAME (competitive inhibitor of NO synthase), 10 mg/kg i.p., 30 min before ischemia, and 5 mg/kg, 5 min after ischemia; BN52020 and BN52021 (inhibitors of platelet-activating factor: PAF receptors) were administered as a suspension in 5% ethanol in water by oral route, 10 mg/kg for 3 days before ischemia. Three of these drugs, MK-801, L-NAME, and BN52021, significantly reduced ischemia-elevated activity of PKC and ODC, whereas AP1 formation was only partially attenuated. Our observations implicate the existence of different mechanism(s) for postischemic PKC and ODC activation, which in turn is engaged in AP1 induction.
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Affiliation(s)
- B Zabłocka
- Department of Neurochemistry, Polish Academy of Sciences, Warsaw
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41
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Lukasiuk K, Kaczmarek L, Condorelli DF. Inducible and constitutive transcription factor NF-kappa B-like DNA binding activities in rat brain cells cultured in vitro. Neurochem Int 1995; 26:173-8. [PMID: 7599537 DOI: 10.1016/0197-0186(94)00121-a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Description of constitutive and inducible transcription factors in brain cells is a prerequisite for understanding phenomena of long-term neuronal plasticity. In this report we report that basal levels of NF-kappa B-like transcription factor DNA binding activity (measured by electrophoretic mobility shift assay) are observed in two kinds of cultured rat brain cells, namely neurons of fetal cerebral hemispheres and astroglia derived from newborn brains. In the latter culture, phorbol ester induces additional forms of DNA binding activity, whereas L-glutamate fails to do so. In neurons, neither treatment is effective in inducing NF-kappa B-like DNA binding activity over the basal level. These results are in contrast to the fact that L-glutamate in both neurons and glia elevates DNA binding activity of AP-1, another transcription factor. These data, besides describing behavior of NF-kappa B-like DNA binding activities, also provide some evidence that L-glutamate exerts its modulatory functions on neurons and glia through specific transcription factors like AP-1.
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Affiliation(s)
- K Lukasiuk
- Institute of Biochemistry, Faculty of Medicine, University of Catania, Italy
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42
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Kohmura E, Yuguchi T, Yamada K, Sakaguchi T, Wanaka A, Hayakawa T. Expression of c-fos mRNA after cortical ablation in rat brain is modulated by basic fibroblast growth factor (bFGF) and the NMDA receptor is involved in c-fos expression. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1995; 28:117-21. [PMID: 7707864 DOI: 10.1016/0169-328x(94)00198-n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Expression of c-fos mRNA after cortical injury was studied using the in situ hybridization technique. Strong signals for c-fos mRNA were observed immediately after cortical ablation in neurons throughout the cortex ipsilateral to the injury. However, this c-fos mRNA expression was transient and disappeared within 6 h after the injury. When basic fibroblast growth factor (bFGF; 1 micrograms) was applied to the site of ablation, c-fos mRNA signals were observed for a much longer period. Even 24 h after injury, diffuse expression of c-fos mRNA was detected throughout the cortex, being mainly confined to non-neuronal cells. Intraperitoneal injection of MK-801 (3 mg/kg), a non-competitive NMDA receptor antagonist, suppressed the expression of c-fos mRNA after cortical ablation. It suppressed both the immediate and late expression induced by cortical ablation and bFGF. The immediate expression of c-fos in neurons is likely to be due to spreading depression, while neuronal-glial interactions would be involved in the mechanism of late c-fos expression by non-neuronal cells. Our results suggest that induction of c-fos after cortical injury can be modulated by topically applied bFGF and that the N-methyl-D-aspartate (NMDA) receptor is involved in c-fos expression not only caused by injury itself but also induced by injury and bFGF. As the immediate early genes regulate secondary gene responses, the induction of c-fos may contribute to neuronal plasticity and bFGF may enhance its effect.
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Affiliation(s)
- E Kohmura
- Department of Neurosurgery, Osaka University Medical School, Japan
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43
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Kaminska B, Filipkowski RK, Zurkowska G, Lason W, Przewlocki R, Kaczmarek L. Dynamic changes in the composition of the AP-1 transcription factor DNA-binding activity in rat brain following kainate-induced seizures and cell death. Eur J Neurosci 1994; 6:1558-66. [PMID: 7850019 DOI: 10.1111/j.1460-9568.1994.tb00546.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Kainate, a potent excitatory and neurotoxic agent, has also proved useful in studies on other glutamate-driven phenomena, such as neuronal plasticity. Long-term effects of kainate are apparently dependent on its influence on the expression of various genes, including those encoding the AP-1 transcription factor, consisting of proteins belonging to the Fos and Jun families. In our studies we analysed c-fos, fos B, c-jun, jun B and jun D mRNA levels as well as a functional feature of AP-1, its DNA-binding activity, in the rat brain following systemic injection of kainate. Two phases of elevated AP-1 DNA-binding activity were observed in the hippocampus and entorhinal cortex, and were correlated with period of seizures (2 and 6 h after kainate injection) and neuron damage (48-72 h). At 72 h after kainate treatment DNA fragmentation, believed to be diagnostic of apoptotic processes typical of programmed cell death phenomena, was noted. Two and six hours after the treatment, AP-1 consisted predominantly of Fos B, c-Fos, Fra-2 and Jun B, while at 72 h Jun D constituted the major AP-1 component in place of Jun B, and no c-Fos was detected. Only a slight AP-1 increase was seen 24 h after kainate treatment. In the sensory cortex, only the late phase of AP-1 elevation was detected. Contrary to AP-1, no effect of kainate on levels of two other transcription factors, CREB/ATF (cAMP-responsive element binding proteins) and OCT (octamer element DNA-binding activity) was seen.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B Kaminska
- Nencki Institute of Experimental Biology, Warsaw, Poland
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44
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Smith TL. Selective effects of ethanol exposure on metabotropic glutamate receptor and guanine nucleotide stimulated phospholipase C activity in primary cultures of astrocytes. Alcohol 1994; 11:405-9. [PMID: 7818799 DOI: 10.1016/0741-8329(94)90025-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of acute and chronic ethanol exposures on the stimulation of inositol specific phospholipase C by metabotropic glutamate receptor activation were determined in primary cultures of rat cortical astrocytes. Phospholipase C activity was monitored by the formation of [3H]inositol phosphates in the presence of lithium in cells prelabelled with [3H]inositol. Acute exposure to 200 mM ethanol had no significant effect on either basal or L-glutamate stimulated [3H]inositol phosphate formation. In cells chronically exposed to ethanol for 4 days, the [3H]inositol phosphate responses to L-glutamate, quisqualate, and the selective metabotropic receptor agonist, 1S,3R-1-amino-cyclopentane-1,3 dicarboxylic acid (trans-ACPD), were significantly inhibited when compared to control (untreated) cells. In contrast, chronic ethanol exposure had no significant effect on the [3H]inositol phosphate response to endothelin-1, a peptide structurally and functionally unrelated to L-glutamate. Similarly, the stimulation of [3H]inositol phosphate formation by the stable GTP analog, guanine 5'-(gamma-thiotrisphosphate), was also unaffected by chronic ethanol exposure. The results suggest that chronic ethanol exposure does not affect the coupling of GTP binding proteins to phospholipase C, but rather acts in a selective manner to either alter the metabotropic receptor number or to disrupt the normal coupling of this receptor to its GTP binding protein, which may in turn affect receptor affinity.
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Affiliation(s)
- T L Smith
- Department of Veterans Affairs Medical Center, Research Service (151), Tucson, Arizona 85723
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45
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Gallo V, Patneau DK, Mayer ML, Vaccarino FM. Excitatory amino acid receptors in glial progenitor cells: molecular and functional properties. Glia 1994; 11:94-101. [PMID: 7927651 DOI: 10.1002/glia.440110204] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have analyzed the molecular and biophysical properties of glutamate-gated channels in cells of the oligodendrocyte lineage, using both the CG-4 primary cell line (Louis et al: J. Neurosci. Res. 31:193-204, 1992a) and oligodendrocyte progenitors purified from the rat cerebral cortex. CG-4 progenitor cells, as well as primary progenitors, were stained with a specific anti-GABA antibody. In whole-cell patch-clamp recordings, rapid perfusion of the agonists L-glutamate, kainate, and AMPA produced rapidly desensitizing currents in CG-4 cells. NMDA was ineffective. Both rapidly desensitizing and steady-state components of responses to kainate were inhibited by the kainate/AMPA receptor antagonist CNQX. Northern blot analysis of total mRNA isolated from CG-4 cells revealed co-expression of both AMPA- and kainate-preferring glutamate receptor subunits. The activation of glutamate receptors in CG-4 cells caused a rapid and transient elevation of mRNAs for the immediate early gene NGFI-A.
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Affiliation(s)
- V Gallo
- Laboratory of Cellular and Molecular Neurophysiology, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland 20892
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46
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Matute C, Pulakat L, Río C, Valcárcel C, Miledi R. Properties of angiotensin II receptors in glial cells from the adult corpus callosum. Proc Natl Acad Sci U S A 1994; 91:3774-8. [PMID: 8170986 PMCID: PMC43664 DOI: 10.1073/pnas.91.9.3774] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The existence and the properties of angiotensin II receptors in the adult bovine and human corpus callosum (CC) were investigated by using Xenopus oocytes and primary glial cell cultures. In oocytes injected with CC mRNA, angiotensin II elicited oscillatory Cl- currents due to activation of the inositol phosphate/Ca(2+)-receptor-channel coupling system. The receptors expressed in oocytes and in CC cultures were pharmacologically similar to the AT1 receptor type as assayed by binding. Northern blot analysis and in situ hybridization studies in sections from CC and in glial cultures revealed that the receptors were molecularly related to the AT1 receptor and that they were present in astrocytes. In these cells, activation of the receptors with angiotensin II increased de novo DNA synthesis, promoted the release of aldosterone, and induced c-Fos expression. These findings indicate that CC astrocytes possess functional AT1 receptors that participate in various physiological processes.
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Affiliation(s)
- C Matute
- Department of Psychobiology, University of California, Irvine 92717
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47
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Pende M, Holtzclaw LA, Curtis JL, Russell JT, Gallo V. Glutamate regulates intracellular calcium and gene expression in oligodendrocyte progenitors through the activation of DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Proc Natl Acad Sci U S A 1994; 91:3215-9. [PMID: 8159727 PMCID: PMC43546 DOI: 10.1073/pnas.91.8.3215] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Oligodendrocytes and their progenitors (O-2A) express functional kainate- and DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-preferring glutamate receptors. The physiological consequences of activation of these receptors were studied in purified rat cortical O-2A progenitors and in the primary oligodendrocyte cell line CG-4. Changes in the mRNA levels of a set of immediate early genes were studied and were correlated to intracellular Ca2+ concentration, as measured by fura-2 Ca2+ imaging. Both in CG-4 and in cortical O-2A progenitors, basal mRNA levels of NGFI-A were much higher than c-fos, c-jun, or jun-b. Glutamate, kainate, and AMPA greatly increased NGFI-A mRNA and protein by activation of membrane receptors in a Ca(2+)-dependent fashion. Agonists at non-N-methyl-D-aspartate receptors promoted transmembrane Ca2+ influx through voltage-dependent channels as well as kainate and/or AMPA channels. The influx of Ca2+ ions occurring through glutamate-gated channels was sufficient by itself to increase the expression of NGFI-A mRNA. AMPA receptors were found to be directly involved in intracellular Ca2+ and NGFI-A mRNA regulation, because the effects of kainate were greatly enhanced by cyclothiazide, an allosteric modulator that selectively suppresses desensitization of AMPA but not kainate receptors. Our results indicate that glutamate acting at AMPA receptors regulates immediate early gene expression in cells of the oligodendrocyte lineage by increasing intracellular calcium. Consequently, modulation of these receptor channels may have immediate effects at the genomic level and regulate oligodendrocyte development at critical stages.
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Affiliation(s)
- M Pende
- Laboratory of Cellular and Molecular Neurophysiology, National Institute of Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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48
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Mack KJ, Kriegler S, Chang S, Chiu SY. Transcription factor expression is induced by axonal stimulation and glutamate in the glia of the developing optic nerve. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 23:73-80. [PMID: 7913204 DOI: 10.1016/0169-328x(94)90213-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recent experiments have demonstrated that stimulation of the developing optic nerve affects several glial cell characteristics, such as ionic fluxes and cell proliferation. This investigation asked if transcription factor expression may be another stimulation-dependent process in the glia of the developing optic nerve. In unstimulated optic nerves, an antibody to c-fos-related antigens demonstrated positive cell body staining at postnatal days (P) 2, 7, 14, and 60. This nuclear staining was most prominent at early postnatal ages, although young adult (P60) optic nerves showed occasional positive cells. To demonstrate the inducibility of transcription factor antigens, optic nerves from P7 animals received intermittent 15-20 Hz electrical stimulation for 5-15 min. Two hours after this stimulation, an increased number of immunoreactive cells for c-fos-related antigens, c-jun, and NGFI-A was demonstrated. Additionally, optic nerves were exposed for 5-30 min to a solution of 300 microM glutamate, latter maintained in a glutamate-free solution for 2 h, and then quickly frozen. Glutamate-treated nerves showed an increased expression of c-fos-related antigens compared to control nerves. No c-fos increase was seen in the absence of calcium. Expression of c-fos or NGFI-A occurred in cells that were S-100 positive, and most likely represented type 1 astrocytes. These studies indicate that developing (P7) optic nerves show a baseline expression of c-fos-related antigens, c-jun and NGFI-A. Stimulation through electrical nerve stimulation or glutamate results in an increased expression of these transcription factors.
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Affiliation(s)
- K J Mack
- Waisman Center on Mental Retardation, Department of Neurology, University of Wisconsin, Madison 53717
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Condorelli DF, Dell'Albani P, Amico C, Lukasiuk K, Kaczmarek L, Giuffrida-Stella AM. Glutamate receptor-driven activation of transcription factors in primary neuronal cultures. Neurochem Res 1994; 19:489-99. [PMID: 7520539 DOI: 10.1007/bf00967329] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have used primary neuronal cultures prepared from fetal cerebral hemispheres to investigate the effects of different glutamate receptor agonists and antagonists on the expression of transcription factor encoding genes, such as c-fos, fosB, c-jun, junB, junD, c-myc, and zif/268. The addition of glutamate (100 microM) to the culture medium rapidly activated c-fos, fosB, c-jun, junB and zif/268 gene expression, reaching the maximal level at 30-60 minutes for zif/268 and at 60 minutes for the other genes. The onset of fosB mRNA accumulation was slightly delayed in comparison to the other genes. No clear induction was found for junD and c-myc. Different glutamate receptor agonists, such as NMDA, kainate, quisqualate, trans-(+/-)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) were able to increase c-fos, c-jun, and zif-268 mRNA levels with rapid and transient kinetics similar to those observed after glutamate treatment. Similar results were obtained for junB and fosB after kainate and quisqualate stimulation. Pretreatment with MK-801, a non competitive NMDA antagonist, produced an almost complete inhibition of glutamate-driven expression of transcription factor genes, thus suggesting that NMDA receptor plays a major role in glutamate induced-gene expression. On the contrary the kainate/AMPA receptor antagonist, DNQX, did not influence glutamate induced-gene expression. Under the conditions used in the present study, NMDA was effective in inducing the simultaneous activation of several IEGs even when added to the culture medium containing millimolar concentration of magnesium. When experiments were performed in Krebs solution, NMDA was effective in stimulating zif/268 and c-fos mRNAs only in the absence of Mg2+, while glutamate activated c-fos and zif/268 both in the presence and absence of magnesium ions. As expected, NMDA effect was fully inhibited by MK-801. The level of AP-1 DNA binding activity, as measured by electrophoretic mobility shift assay, increased after addition of glutamate and NMDA to cultured neurons and such increase was antagonized by the pretreatment with MK-801.
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Affiliation(s)
- D F Condorelli
- Institute of Biochemistry, Faculty of Medicine, University of Catania, Italy
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Kaczmarek L. Glutamate-evoked gene expression in brain cells ? Focus on transcription factors. Amino Acids 1994; 7:245-54. [DOI: 10.1007/bf00807700] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/1993] [Accepted: 10/04/1993] [Indexed: 11/30/2022]
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