101
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Shi P, Raizada MK, Sumners C. Brain cytokines as neuromodulators in cardiovascular control. Clin Exp Pharmacol Physiol 2009; 37:e52-7. [PMID: 19566837 DOI: 10.1111/j.1440-1681.2009.05234.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. The role of cytokines in cardiovascular control, especially in neurogenic hypertension, has received considerable attention during the past few years. Brain cytokines have been shown to exert profound effects on neuronal activity. Recently, a number of studies have shown that administration of pro-inflammatory cytokines or anti-inflammatory cytokines into the central nervous system has a significant impact on sympathetic outflow, arterial pressure and cardiac remodelling in experimental models of hypertension and heart failure. 2. Our objective in this review is to present a succinct account of the effect of cytokines on neuronal activity and their role in cardiovascular disease. Furthermore, we propose a hypothesis for a neuromodulatory role of cytokines in the neural control of cardiovascular function.
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Affiliation(s)
- Peng Shi
- Department of Physiology and Functional Genomics, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610-0274, USA
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102
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Excitotoxic death of retinal neurons in vivo occurs via a non-cell-autonomous mechanism. J Neurosci 2009; 29:5536-45. [PMID: 19403821 DOI: 10.1523/jneurosci.0831-09.2009] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The central hypothesis of excitotoxicity is that excessive stimulation of neuronal NMDA-sensitive glutamate receptors is harmful to neurons and contributes to a variety of neurological disorders. Glial cells have been proposed to participate in excitotoxic neuronal loss, but their precise role is defined poorly. In this in vivo study, we show that NMDA induces profound nuclear factor kappaB (NF-kappaB) activation in Müller glia but not in retinal neurons. Intriguingly, NMDA-induced death of retinal neurons is effectively blocked by inhibitors of NF-kappaB activity. We demonstrate that tumor necrosis factor alpha (TNFalpha) protein produced in Müller glial cells via an NMDA-induced NF-kappaB-dependent pathway plays a crucial role in excitotoxic loss of retinal neurons. This cell loss occurs mainly through a TNFalpha-dependent increase in Ca(2+)-permeable AMPA receptors on susceptible neurons. Thus, our data reveal a novel non-cell-autonomous mechanism by which glial cells can profoundly exacerbate neuronal death following excitotoxic injury.
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103
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Balosso S, Ravizza T, Pierucci M, Calcagno E, Invernizzi R, Di Giovanni G, Esposito E, Vezzani A. Molecular and functional interactions between tumor necrosis factor-alpha receptors and the glutamatergic system in the mouse hippocampus: Implications for seizure susceptibility. Neuroscience 2009; 161:293-300. [DOI: 10.1016/j.neuroscience.2009.03.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 03/03/2009] [Accepted: 03/04/2009] [Indexed: 12/29/2022]
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104
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Mode of action of cytokines on nociceptive neurons. Exp Brain Res 2009; 196:67-78. [PMID: 19290516 DOI: 10.1007/s00221-009-1755-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 02/24/2009] [Indexed: 01/05/2023]
Abstract
Cytokines are pluripotent soluble proteins secreted by immune and glial cells and are key elements in the induction and maintenance of pain. They are categorized as pro-inflammatory cytokines, which are mostly algesic, and anti-inflammatory cytokines, which have analgesic properties. Progress has been made in understanding the mechanisms underlying the action of cytokines in pain. To date, several direct and indirect pathways are known that link cytokines with nociception or hyperalgesia. Cytokines may act via specific cytokine receptors inducing downstream signal transduction cascades, which then modulate the function of other receptors like the ionotropic glutamate receptor, the transient vanilloid receptors, or sodium channels. This receptor activation, either through amplification of the inflammatory reaction, or through direct modulation of ion channel currents, then results in pain sensation. Following up on results from animal experiments, cytokine profiles have recently been investigated in human pain states. An imbalance of pro- and anti-inflammatory cytokine expression may be of importance for individual pain susceptibility. Individual cytokine profiles may be of diagnostic importance in chronic pain states, and, in the future, might guide the choice of treatment.
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105
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Group I metabotropic glutamate receptors control metaplasticity of spinal cord learning through a protein kinase C-dependent mechanism. J Neurosci 2009; 28:11939-49. [PMID: 19005059 DOI: 10.1523/jneurosci.3098-08.2008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neurons within the spinal cord can support several forms of plasticity, including response-outcome (instrumental) learning. After a complete spinal transection, experimental subjects are capable of learning to hold the hindlimb in a flexed position (response) if shock (outcome) is delivered to the tibialis anterior muscle when the limb is extended. This response-contingent shock produces a robust learning that is mediated by ionotropic glutamate receptors (iGluRs). Exposure to nociceptive stimuli that are independent of limb position (e.g., uncontrollable shock; peripheral inflammation) produces a long-term (>24 h) inhibition of spinal learning. This inhibition of plasticity in spinal learning is itself a form of plasticity that requires iGluR activation and protein synthesis. Plasticity of plasticity (metaplasticity) in the CNS has been linked to group I metabotropic glutamate receptors (subtypes mGluR1 and mGluR5) and activation of protein kinase C (PKC). The present study explores the role of mGluRs and PKC in the metaplastic inhibition of spinal cord learning using a combination of behavioral, pharmacological, and biochemical techniques. Activation of group I mGluRs was found to be both necessary and sufficient for metaplastic inhibition of spinal learning. PKC was activated by stimuli that inhibit spinal learning, and inhibiting PKC activity restored the capacity for spinal learning. Finally, a PKC inhibitor blocked the metaplastic inhibition of spinal learning produced by a group I mGluR agonist. The data strongly suggest that group I mGluRs control metaplasticity of spinal learning through a PKC-dependent mechanism, providing a potential therapeutic target for promoting use-dependent plasticity after spinal cord injury.
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106
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Youn DH, Wang H, Jeong SJ. Exogenous tumor necrosis factor-alpha rapidly alters synaptic and sensory transmission in the adult rat spinal cord dorsal horn. J Neurosci Res 2008; 86:2867-75. [PMID: 18543334 DOI: 10.1002/jnr.21726] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) is involved in the generation of inflammatory and neuropathic pain. This study investigated if TNF-alpha has any effect on spinal synaptic and/or sensory transmission by using whole-cell recordings of substantia gelatinosa (SG) neurons in transverse lumbar spinal cord slices of adult rats and by using behavioral tests. After intrathecal administration of TNF-alpha in adult rats, spontaneous hind paw withdrawal behavior and thermal hyperalgesia were rapidly induced (approximately 30 min), while mechanical allodynia slowly developed. Bath application of TNF-alpha (0.1-1 nM, 8 min) depressed peak amplitude of monosynaptic Adelta and C fiber-evoked excitatory postsynaptic currents (EPSCs) without changing in holding currents and input resistances, whereas this application generally potentiated polysynaptic Adelta fiber-evoked EPSCs. Moreover, the frequencies, but not the amplitudes, of spontaneous and miniature EPSCs and spontaneous inhibitory postsynaptic currents were significantly increased by bath-applied TNF-alpha in most of the SG neurons. The effects of TNF-alpha on Adelta/C fiber-evoked monosynaptic and polysynaptic or spontaneous EPSCs were significantly blocked by 5 microM TNF-alpha antagonist that inhibits TNF-alpha binding to its type 1 receptor (TNFR1). Because this study also found high protein expression of TNFR1 in the adult dorsal root ganglion and no change of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) induced whole-cell currents by TNF-alpha, we conclude that presynaptic TNFR1 at Adelta/C primary afferent terminals contributes to the rapid alteration of synaptic transmission in the spinal SG, and the development of abnormal pain hypersensitivity by exogenous TNF-alpha.
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Affiliation(s)
- Dong-Ho Youn
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA.
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107
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Park KM, Yule DI, Bowers WJ. Tumor necrosis factor-alpha potentiates intraneuronal Ca2+ signaling via regulation of the inositol 1,4,5-trisphosphate receptor. J Biol Chem 2008; 283:33069-79. [PMID: 18838384 PMCID: PMC2586262 DOI: 10.1074/jbc.m802209200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 09/12/2008] [Indexed: 01/01/2023] Open
Abstract
Inflammatory events have long been implicated in initiating and/or propagating the pathophysiology associated with a number of neurological diseases. In addition, defects in Ca2+-handling processes, which shape membrane potential, influence gene transcription, and affect neuronal spiking patterns, have also been implicated in disease progression and cognitive decline. The mechanisms underlying the purported interplay that exists between neuroinflammation and Ca2+ homeostasis have yet to be defined. Herein, we describe a novel neuron-intrinsic pathway in which the expression of the type-1 inositol 1,4,5-trisphosphate receptor is regulated by the potent pro-inflammatory cytokine tumor necrosis factor-alpha. Exposure of primary murine neurons to tumor necrosis factor-alpha resulted in significant enhancement of Ca2+ signals downstream of muscarinic and purinergic stimulation. An increase in type-1 inositol 1,4,5-trisphosphate receptor mRNA and protein steady-state levels following cytokine exposure positively correlated with this alteration in Ca2+ homeostasis. Modulation of Ca2+ responses arising from this receptor subtype and its downstream effectors may exact significant consequences on neuronal function and could underlie the compromise in neuronal activity observed in the setting of chronic neuroinflammation, such as that associated with Parkinson disease and Alzheimer disease.
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Affiliation(s)
- Keigan M Park
- Center for Neural Development and Disease, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York 14642, USA
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108
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Savin C, Triesch J, Meyer-Hermann M. Epileptogenesis due to glia-mediated synaptic scaling. J R Soc Interface 2008; 6:655-68. [PMID: 18986963 DOI: 10.1098/rsif.2008.0387] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Homeostatic regulation of neuronal activity is fundamental for the stable functioning of the cerebral cortex. One form of homeostatic synaptic scaling has been recently shown to be mediated by glial cells that interact with neurons through the diffusible messenger tumour necrosis factor-alpha (TNF-alpha). Interestingly, TNF-alpha is also used by the immune system as a pro-inflammatory messenger, suggesting potential interactions between immune system signalling and the homeostatic regulation of neuronal activity. We present the first computational model of neuron-glia interaction in TNF-alpha-mediated synaptic scaling. The model shows how under normal conditions the homeostatic mechanism is effective in balancing network activity. After chronic immune activation or TNF-alpha overexpression by glia, however, the network develops seizure-like activity patterns. This may explain why under certain conditions brain inflammation increases the risk of seizures. Additionally, the model shows that TNF-alpha diffusion may be responsible for epileptogenesis after localized brain lesions.
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Affiliation(s)
- Cristina Savin
- Frankfurt Institute for Advanced Studies, Ruth Moufang Strasse 1, 60438 Frankfurt am Main, Germany.
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109
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Simões PF, Silva AP, Pereira FC, Marques E, Milhazes N, Borges F, Ribeiro CF, Macedo TR. Methamphetamine Changes NMDA and AMPA Glutamate Receptor Subunit Levels in the Rat Striatum and Frontal Cortex. Ann N Y Acad Sci 2008; 1139:232-41. [DOI: 10.1196/annals.1432.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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110
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Zhao P, Ignacio S, Beattie EC, Abood ME. Altered presymptomatic AMPA and cannabinoid receptor trafficking in motor neurons of ALS model mice: implications for excitotoxicity. Eur J Neurosci 2008; 27:572-9. [PMID: 18279310 DOI: 10.1111/j.1460-9568.2008.06041.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder involving the selective loss of spinal cord motor neurons. Excitotoxicity mediated by glutamate has been implicated as a cause of this progressive degeneration. In this study we examined two types of receptors, the excitatory alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors (AMPARs) and inhibitory cannabinoid receptor (CB1) with respect to their localization and total expression in spinal cord motor neurons. AMPAR and CB1 represent major excitatory and inhibitory transmission input, respectively, and their expression levels on the plasma membrane have direct relevance to the vulnerability of the motor neurons to glutamatergic excitotoxicity. We used quantitative immunofluorescence microscopy to comparatively measure the total cellular expression and the synaptic localization of specific subclasses of AMPARs [as determined by the presence of the subunits glutamate receptor 1 (GluR1) or glutamate receptor 2 (GluR2)] and CB1 in spinal cord motor neurons during disease progression in a G93ASOD1 mouse model of ALS. We found an increase in synaptic GluR1 and a decrease of synaptic and total GluR2 at early ages (6 weeks, prior to disease onset). Total CB1 receptor levels were decreased at 6 weeks old. We determined the gene expression of CB1, GluR1 and GluR2 using quantitative real-time reverse transcriptase-polymerase chain reaction. The decreased synaptic and total GluR2 and increased synaptic GluR1 levels may result in increased numbers of Ca2+-permeable AMPARs, thus contributing to neuronal death. Early alterations in CB1 expression may also predispose motor neurons to excitotoxicity. To our knowledge, this is the first demonstration of presymptomatic changes in trafficking of receptors that are in direct control of excitotoxicity and death in a mouse model of ALS.
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Affiliation(s)
- Pingwei Zhao
- Forbes Norris ALS/MDA Research Center, California Pacific Medical Center Research Institute, 475 Brannan St, Suite 220, San Francisco, CA 94107, USA
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111
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Rapid tumor necrosis factor alpha-induced exocytosis of glutamate receptor 2-lacking AMPA receptors to extrasynaptic plasma membrane potentiates excitotoxicity. J Neurosci 2008; 28:2119-30. [PMID: 18305246 DOI: 10.1523/jneurosci.5159-07.2008] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The postinjury inflammatory response in the CNS leads to neuronal excitotoxicity. Our previous studies show that a major component of this response, the inflammatory cytokine tumor necrosis factor alpha (TNFalpha), causes a rapid increase in AMPA glutamate receptors (AMPARs) on the plasma membrane of cultured hippocampal neurons. This may potentiate neuron death through an increased vulnerability to AMPAR-dependent excitotoxic stress. Here, we test this hypothesis with an in vitro lactose dehydrogenase death assay and examine in detail the AMPAR surface delivery time course, receptor subtype, and synaptic and extrasynaptic distribution after TNFalpha exposure. These data demonstrate that surface levels of glutamate receptor 2 (GluR2)-lacking Ca2+-permeable AMPARs peak at 15 min after TNFalpha treatment, and the majority are directed to extrasynaptic sites. TNFalpha also induces an increase in GluR2-containing surface AMPARs but with a slower time course. We propose that this activity contributes to excitotoxic neuron death because TNFalpha potentiation of kainate excitotoxicity is blocked by a Ca2+-permeable AMPAR antagonist [NASPM (1-naphthyl acetyl spermine)] and a specific phosphoinositide 3 kinase (PI3 kinase) inhibitor (LY294,002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one]) previously shown to block the TNFalpha-induced increase in AMPAR surface delivery. This information forms the basis for future in vivo studies examining AMPAR-dependent potentiation of excitotoxic neuron death and dysfunction caused by TNFalpha after acute injury and during neurodegenerative or neuropsychiatric disorders.
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112
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Effect of cytokines on neuronal excitability. Neurosci Lett 2008; 437:188-93. [PMID: 18420346 DOI: 10.1016/j.neulet.2008.03.052] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2007] [Revised: 02/28/2008] [Accepted: 03/19/2008] [Indexed: 01/11/2023]
Abstract
Numerous studies have shown that proinflammatory cytokines induce or facilitate pain and hyperalgesia in the presence of inflammation, injury to the nervous system or cancer. Besides acting as inflammatory mediators, increasing evidence indicates that cytokines may also specifically interact with receptor and ion channels regulating neuronal excitability, synaptic plasticity and injury under both physiological and pathological conditions. Here we summarize findings on two prototypical proinflammatory cytokines, tumor-necrosis factor-alpha and interleukin-1 beta, and their effects on neuronal excitability and ion channels with special regards to pain and hyperalgesia.
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113
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Czeschik JC, Hagenacker T, Schäfers M, Büsselberg D. TNF-alpha differentially modulates ion channels of nociceptive neurons. Neurosci Lett 2008; 434:293-8. [PMID: 18314270 DOI: 10.1016/j.neulet.2008.01.070] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/04/2008] [Accepted: 01/29/2008] [Indexed: 11/16/2022]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine involved in the development and maintenance of inflammatory and neuropathic pain conditions. The mechanisms by which TNF-alpha elicits pain behavior are still incompletely understood. Numerous studies suggest that TNF-alpha sensitizes primary afferent neurons. Most recently, it was shown that TNF-alpha induced an enhancement of TTX-R Na(+) current in dorsal root ganglion (DRG) cells. In the present study, we have tested the effect of acute application of TNF-alpha on voltage-gated potassium, calcium and sodium channel currents as well as its influence on membrane conductance in isolated rat DRG neurons. We report that voltage-gated potassium channel currents of nociceptive DRG neurons are not influenced by TNF-alpha (100 ng/ml), while voltage-gated calcium channel currents were decreased voltage-dependently by -7.73+/-6.01% (S.D.), and voltage-activated sodium channels currents were increased by +5.62+/-4.27%, by TNF-alpha. In addition, TNF-alpha induced a significant increase in IV ramps at a potential of +20 mV, which did not exist when the experiments were conducted in a potassium-free solution, indicating that this effect is mainly the result of a change in potassium conductance. These different actions of TNF-alpha might help to explain how it sensitizes primary afferent neurons after nerve injury and thus facilitates pain.
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114
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Wakita H, Ruetzler C, Illoh KO, Chen Y, Takanohashi A, Spatz M, Hallenbeck JM. Mucosal tolerization to E-selectin protects against memory dysfunction and white matter damage in a vascular cognitive impairment model. J Cereb Blood Flow Metab 2008; 28:341-53. [PMID: 17637705 PMCID: PMC2601631 DOI: 10.1038/sj.jcbfm.9600528] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Vascular cognitive impairment (VCI) is the second most prevalent type of dementia in the world. The white matter damage that characterizes the common subcortical ischemic form of VCI can be modeled by ligating both common carotid arteries in the Wistar rat to induce protracted cerebral hypoperfusion. In this model, we find that repetitive intranasal administration of recombinant E-selectin to induce mucosal tolerance and to target immunomodulation to activating blood vessels potently suppresses both white matter (and possibly gray matter) damage and markers of vessel activation (tumor necrosis factor and E-selectin); it also preserves behavioral function in T-maze spontaneous alternation, T-maze spatial discrimination memory retention, and object recognition tests. Immunomodulation may be an effective novel strategy to prevent progression of VCI.
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Affiliation(s)
- Hideaki Wakita
- Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-4476, USA
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115
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Lin CY, Hilgenberg LGW, Smith MA, Lynch G, Gall CM. Integrin regulation of cytoplasmic calcium in excitatory neurons depends upon glutamate receptors and release from intracellular stores. Mol Cell Neurosci 2008; 37:770-80. [PMID: 18289871 DOI: 10.1016/j.mcn.2008.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 11/27/2007] [Accepted: 01/03/2008] [Indexed: 01/12/2023] Open
Abstract
Integrins regulate cytoplasmic calcium levels ([Ca(2+)]i) in various cell types but information on activities in neurons is limited. The issue is of current interest because of the evidence that both integrins and changes in [Ca(2+)]i are required for Long-Term Potentiation. Accordingly, the present studies evaluated integrin ligand effects in cortical neurons. Integrin ligands or alpha5beta1 integrin activating antisera rapidly increased [Ca(2+)]i with effects greater in glutamatergic than GABAergic neurons, absent in astroglia, and blocked by beta1 integrin neutralizing antisera and the tyrosine kinase antagonist genistein. Increases depended upon extracellular calcium and intracellular store release. Ligand-induced effects were reduced by voltage-sensitive calcium channel and NMDA receptor antagonists, but blocked by tetrodotoxin or AMPA receptor antagonists. These results indicate that integrin ligation triggers AMPA receptor/depolarization-dependent calcium influx followed by intracellular store release and suggest the possibility that integrin modulation of activity-induced changes in [Ca(2+)]i contributes importantly to lasting synaptic plasticity in forebrain neurons.
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Affiliation(s)
- C-Y Lin
- Department of Anatomy and Neurobiology, University of California, Irvine CA 92697-4292, USA
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116
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Homeostatic regulation of AMPA receptor expression at single hippocampal synapses. Proc Natl Acad Sci U S A 2008; 105:775-80. [PMID: 18174334 DOI: 10.1073/pnas.0706447105] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Homeostatic synaptic response is an important measure in confining neuronal activity within a narrow physiological range. Whether or not homeostatic plasticity demonstrates synapse specificity, a key feature characteristic of Hebbian-type plasticity, is largely unknown. Here, we report that in cultured hippocampal neurons, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid subtype glutamate receptor (AMPAR) accumulation is increased selectively in chronically inhibited single synapses, whereas the neighboring normal synapses remain unaffected. This synapse-specific homeostatic regulation depends on the disparity of synaptic activity and is mediated by GluR2-lacking AMPARs and PI3-kinase signaling. These results demonstrate the existence of synaptic specificity and the crucial role of AMPAR-gated calcium in homeostatic plasticity in central neurons.
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117
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Developmental expression of Ca2+-permeable AMPA receptors underlies depolarization-induced long-term depression at mossy fiber CA3 pyramid synapses. J Neurosci 2007; 27:11651-62. [PMID: 17959808 DOI: 10.1523/jneurosci.2671-07.2007] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Many central excitatory synapses undergo developmental alterations in the molecular and biophysical characteristics of postsynaptic ionotropic glutamate receptors via changes in subunit composition. Concerning AMPA receptors (AMPARs), glutamate receptor 2 subunit (GluR2)-containing, Ca2+-impermeable AMPARs (CI-AMPARs) prevail at synapses between mature principal neurons; however, accumulating evidence indicates that GluR2-lacking, Ca2+-permeable AMPARs (CP-AMPARs) contribute at these synapses early in development. Here, we used a combination of imaging and electrophysiological recording techniques to investigate potential roles for CP-AMPARs at developing hippocampal mossy fiber-CA3 pyramidal cell (MF-PYR) synapses. We found that transmission at nascent MF-PYR synapses is mediated by a mixed population of CP- and CI-AMPARs as evidenced by polyamine-dependent inwardly rectifying current-voltage (I-V) relationships, and partial philanthotoxin sensitivity of synaptic events. CP-AMPAR expression at MF-PYR synapses is transient, being limited to the first 3 postnatal weeks. Moreover, the expression of CP-AMPARs is regulated by the PDZ (postsynaptic density-95/Discs large/zona occludens-1) domain-containing protein interacting with C kinase 1 (PICK1), because MF-PYR synapses in young PICK1 knock-out mice are philanthotoxin insensitive with linear I-V relationships. Strikingly, MF-PYR transmission via CP-AMPARs is selectively depressed during depolarization-induced long-term depression (DiLTD), a postsynaptic form of MF-PYR plasticity observed only at young MF-PYR synapses. The selective depression of CP-AMPARs during DiLTD was evident as a loss of postsynaptic CP-AMPAR-mediated Ca2+ transients in PYR spines and reduced rectification of MF-PYR synaptic currents. Preferential targeting of CP-AMPARs during DiLTD is further supported by a lack of DiLTD in young PICK1 knock-out mice. Together, these findings indicate that the transient participation of CP-AMPARs at young MF-PYR synapses dictates the developmental window to observe DiLTD.
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118
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Jara JH, Singh BB, Floden AM, Combs CK. Tumor necrosis factor alpha stimulates NMDA receptor activity in mouse cortical neurons resulting in ERK-dependent death. J Neurochem 2007; 100:1407-20. [PMID: 17241124 PMCID: PMC3619402 DOI: 10.1111/j.1471-4159.2006.04330.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Multiple cytokines are secreted in the brain during pro-inflammatory conditions and likely affect neuron survival. Previously, we demonstrated that glutamate and tumor necrosis factor alpha (TNFalpha) kill neurons via activation of the N-methyl-d-aspartate (NMDA) and TNFalpha receptors, respectively. This report continues characterizing the signaling cross-talk pathway initiated during this inflammation-related mechanism of death. Stimulation of mouse cortical neuron cultures with TNFalpha results in a transient increase in NMDA receptor-dependent calcium influx that is additive with NMDA stimulation and inhibited by pre-treatment with the NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid, or the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainate receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione. Pre-treatment with N-type calcium channel antagonist, omega-conotoxin, or the voltage-gated sodium channel antagonist, tetrodotoxin, also prevents the TNFalpha-stimulated calcium influx. Combined TNFalpha and NMDA stimulation results in a transient increase in activity of extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Specific inhibition of ERKs but not JNKs is protective against TNFalpha and NMDA-dependent death. Death is mediated via the low-affinity TNFalpha receptor, TNFRII, as agonist antibodies for TNFRII but not TNFRI stimulate NMDA receptor-dependent calcium influx and death. These data demonstrate how microglial pro-inflammatory secretions including TNFalpha can acutely facilitate glutamate-dependent neuron death.
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Affiliation(s)
- Javier H. Jara
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
| | - Brij B. Singh
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
| | - Angela M. Floden
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
| | - Colin K. Combs
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
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119
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Stone TW, Behan WMH. Interleukin-1β but not tumor necrosis factor-α potentiates neuronal damage by quinolinic acid: Protection by an adenosine A2A receptor antagonist. J Neurosci Res 2007; 85:1077-85. [PMID: 17304576 DOI: 10.1002/jnr.21212] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Quinolinic acid is an agonist at glutamate receptors sensitive to N-methyl-D-aspartate (NMDA). It has been implicated in neural dysfunction associated with infections, trauma, and ischemia, although its neurotoxic potency is relatively low. This study was designed to examine the effects of a combination of quinolinic acid and the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). Compounds were administered to the hippocampus of anesthetized male rats, animals being allowed to recover for 7 days before histological analysis of the hippocampus for neuronal damage estimated by counting of intact, healthy neurons. A low dose of quinolinic acid or IL-1beta produced no damage by itself, but the two together induced a significant loss of pyramidal neurons in the hippocampus. Higher doses produced almost total loss of pyramidal cells. Intrahippocampal TNF-alpha produced no effect alone but significantly reduced the neuronal loss produced by quinolinic acid. The adenosine A(2A) receptor antagonist ZM241385 reduced neuronal loss produced by the combinations of quinolinic acid and IL-1beta. The results suggest that simultaneous quinolinic acid and IL-1beta, both being induced by cerebral infection or injury, are synergistic in the production of neuronal damage and could together contribute substantially to traumatic, infective, or ischemic cerebral damage. Antagonism of adenosine A(2A) receptors protects neurons against the combination of quinolinic acid and IL-1beta.
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Affiliation(s)
- Trevor W Stone
- Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom.
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Ikenaga T, Huesa G, Finger TE. Co-occurrence of calcium-binding proteins and calcium-permeable glutamate receptors in the primary gustatory nucleus of goldfish. J Comp Neurol 2006; 499:90-105. [PMID: 16958099 DOI: 10.1002/cne.21079] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Primary vagal gustatory afferents utilize glutamate as a neurotransmitter acting on AMPA/kainate receptors of second-order neurons. Some forms of ionotropic glutamate receptors permit passage of Ca++ ions upon activation by appropriate ligands. Calcium-binding proteins (CaBPs) play a buffering role for regulating the concentration of intracellular calcium. In the present study, we used immunohistochemistry to examine the distribution and morphology of neurons with CaBPs, including calretinin, calbindin, and parvalbumin, and to compare this distribution with neurons exhibiting Ca++-permeable glutamate receptors as determined by kainate-stimulated uptake of Co++ in the vagal lobe of goldfish. Calretinin- and calbindin-positive neurons occurred throughout the sensory zone including round unipolar, horizontal; and perpendicular bipolar or multipolar somata. Parvalbumin neurons were mainly round monopolar neurons, especially common in the superficial layers of the sensory zone. In the motor zone, while parvalbumin labeled nearly all motoneurons, calretinin labeled only external motoneurons. In double labeling with calretinin and parvalbumin, few neurons in the sensory layer labeled with both antisera. Immunocytochemistry following kainate-stimulate uptake of Co++ showed that most calretinin, but few parvalbumin immunopositive neurons also were labeled by cobalt in the central and deep layers of the sensory zone. All motoneurons were labeled by Co++, including those immunoreactive for calretinin or parvalbumin. These results indicate that calretinin expression is strongly correlated with calcium-permeable ionotropic glutamate receptors in the neurons of the sensory zone of the goldfish vagal lobe, but even within this limited region, not all Ca++-permeable neurons possess any of the CaBPs examined.
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Affiliation(s)
- Takanori Ikenaga
- Department of Cell and Developmental Biology, University of Colorado Medical School, Aurora, Colorado 80045, USA
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121
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Kwak S, Weiss JH. Calcium-permeable AMPA channels in neurodegenerative disease and ischemia. Curr Opin Neurobiol 2006; 16:281-7. [PMID: 16698262 DOI: 10.1016/j.conb.2006.05.004] [Citation(s) in RCA: 196] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 05/04/2006] [Indexed: 11/19/2022]
Abstract
Compelling evidence supports contributions of glutamate receptor overactivation ('excitotoxicity') to neurodegeneration in both acute conditions, such as stroke, and chronic neurodegenerative conditions, such as amyotrophic lateral sclerosis. However, anti-excitotoxic therapeutic trials, which have generally targeted highly Ca2+ permeable NMDA-type glutamate channels, have to date failed to demonstrate impressive efficacy. Whereas most AMPA type glutamate channels are Ca2+ impermeable, an evolving body of evidence supports the contention that relatively unusual Ca2+ permeable AMPA channels might be crucial contributors to injury in these conditions. These channels are preferentially expressed in discrete neuronal subpopulations, and their numbers appear to be upregulated in amyotrophic lateral sclerosis and stroke. In addition, unlike NMDA channels, Ca2+ permeable AMPA channels are not blocked by Mg2+, but are highly permeable to another potentially harmful endogenous cation, Zn2+. The targeting of these channels might provide efficacious new avenues in the therapy of certain neurological diseases.
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Affiliation(s)
- Shin Kwak
- Department of Neurology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8655 Tokyo, Japan
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122
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Elger B, Gieseler M, Schmuecker O, Schumann I, Seltz A, Huth A. Extended therapeutic time window after focal cerebral ischemia by non-competitive inhibition of AMPA receptors. Brain Res 2006; 1085:189-94. [PMID: 16580649 DOI: 10.1016/j.brainres.2006.02.080] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 02/06/2006] [Accepted: 02/09/2006] [Indexed: 11/18/2022]
Abstract
In acute stroke, the therapeutic time window is a critical factor which may have contributed to the failure of several phase III clinical trials with so-called neuroprotective agents. Since cerebral glutamate levels are elevated for many hours in progressing stroke, we investigated the novel AMPA glutamate receptor antagonist ZK 187638 in rodent models of stroke using up to 12 h delays in the start of therapy after permanent occlusion of the middle cerebral artery (MCA). In rats, ZK 187638 reduced total infarct volume by 43% and 33% when therapy was started immediately or with a delay of 6 h, respectively, but no effect was observed after a 12 h delay. Dose-dependent decreases of total infarct volume (up to 42%) were measured in mice given the first injection of ZK 187638 6 h after permanent MCA occlusion. In conclusion, the AMPA receptor antagonist ZK 187638 has a therapeutic time window of at least 6 h after permanent focal cerebral ischemia in rodents.
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123
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Myers RR, Campana WM, Shubayev VI. The role of neuroinflammation in neuropathic pain: mechanisms and therapeutic targets. Drug Discov Today 2006; 11:8-20. [PMID: 16478686 DOI: 10.1016/s1359-6446(05)03637-8] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neuroinflammation is a proinflammatory cytokine-mediated process that can be provoked by systemic tissue injury but it is most often associated with direct injury to the nervous system. It involves neural-immune interactions that activate immune cells, glial cells and neurons and can lead to the debilitating pain state known as neuropathic pain. It occurs most commonly with injury to peripheral nerves and involves axonal injury with Wallerian degeneration mediated by hematogenous macrophages. Therapy is problematic but new trials with anti-cytokine agents, cytokine receptor antibodies, cytokine-signaling inhibitors, and glial and neuron stabilizers provide hope for future success in treating neuropathic pain.
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Affiliation(s)
- Robert R Myers
- Department of Anesthesiology (0629), University of California-San Diego, La Jolla, CA 92093-0629, USA.
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