7101
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Erickson MA, Dohi K, Banks WA. Neuroinflammation: a common pathway in CNS diseases as mediated at the blood-brain barrier. Neuroimmunomodulation 2012; 19:121-30. [PMID: 22248728 PMCID: PMC3707010 DOI: 10.1159/000330247] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 06/22/2011] [Indexed: 01/16/2023] Open
Abstract
The blood-brain barrier (BBB) is not simply a physical barrier but a regulatory interface between the central nervous system (CNS) and immune system. The BBB both affects and is affected by the immune system and connects at many levels with the CNS, including the following: (1) the BBB transports cytokines and secretes various substances with neuroinflammatory properties; (2) transporters are altered in disease states including traumatic injury, Alzheimer's disease and inflammatory processes; (3) cytokines and other immune secretions from the cells comprising the BBB are both constitutive and inducible; (4) immune cells are transported across the BBB by the highly regulated process termed diapedesis, which involves communication and interactions between the brain endothelial cells and the immune cells; (5) the neuroimmune system has various effects on the BBB, including modulation of important transport systems and in extreme pathological conditions even disruption of the BBB, and (6) the brain-to-blood efflux transporter P-glycoprotein is altered in inflammatory conditions, thus affecting drug delivery to the brain. In summary, the BBB is an interactive interface that regulates and defines many of the ways that the CNS and the immune system communicate with one another.
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Affiliation(s)
- Michelle A. Erickson
- Geriatrics Research Education and Clinical Center, Puget Sound Health Care System, Seattle, Wash., USA
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Mo., USA
| | - Kenji Dohi
- Geriatrics Research Education and Clinical Center, Puget Sound Health Care System, Seattle, Wash., USA
- Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, Wash., USA
- Department of Emergency and Critical Care Medicine, Showa University School of Medicine, Tokyo, Japan
| | - William A. Banks
- Geriatrics Research Education and Clinical Center, Puget Sound Health Care System, Seattle, Wash., USA
- Division of Gerontology and Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle, Wash., USA
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7102
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Spiegel DR, Chen V. A case of postoperative cognitive decline, with a highly elevated C- reactive protein, status post left ventricular assist device insertion: a review of the neuroinflammatory hypothesis of delirium. Innov Clin Neurosci 2012; 9:35-41. [PMID: 22347689 PMCID: PMC3280076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cognitive difficulties after surgery are a common complication and are associated with significant morbidity and mortality, which is concerning as the number of geriatric patients undergoing major procedures continues to rise. Postoperative cognitive impairment encompasses both postoperative delirium and postoperative cognitive decline. Delirium is a formal diagnosis and presents acutely while postoperative cognitive decline has yet to be defined and has a subtle presentation. Postoperative cognitive decline is a decline in cognitive function from baseline and has been described in elderly patients after cardiac surgery, such as coronary artery bypass graft. Although the etiology of postoperative cognitive decline has yet to be elucidated, it is most likely multifactorial with potential causes being surgery type, sleep disturbances, neuroinflammation, cerebral hypoperfusion, anesthesia, metabolic syndrome, and decreased cognitive reserve. In this case report, we present the first case of postoperative cognitive decline in a middle-age patient after left ventricular assist device placement.
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Affiliation(s)
- David R Spiegel
- Department of Psychiatry and Behavioral Sciences, Eastern Virginia Medical School, Norfolk, Virginia, USA.
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7103
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Abstract
Current therapies for immune-mediated inflammatory disorders in peripheral nerves are non-specific, and partly efficacious. Peripheral nerve regeneration following axonal degeneration or injury is suboptimal, with current therapies focused on modulating the underlying etiology and treating the consequences, such as neuropathic pain and weakness. Despite significant advances in understanding mechanisms of peripheral nerve inflammation, as well as axonal degeneration and regeneration, there has been limited translation into effective new drugs for these disorders. A major limitation in the field has been the unavailability of reliable disease models or research tools that mimic some key essential features of these human conditions. A relatively overlooked aspect of peripheral nerve regeneration has been neurovascular repair required to restore the homeostatic microenvironment necessary for normal function. Using Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) as examples of human acute and chronic immune-mediated peripheral neuroinflammatory disorders respectively, we have performed detailed studies in representative mouse models to demonstrate essential features of the human disorders. These models are important tools to develop and test treatment strategies using realistic outcomes measures applicable to affected patients. In vitro models of the human blood-nerve barrier using endothelial cells derived by endoneurial microvessels provide insights into pro-inflammatory leukocyte-endothelial cell interactions relevant to peripheral neuroinflammation, as well as potential mediators and signaling pathways required for vascular proliferation, angiogenesis, remodeling and tight junction specialization necessary to restore peripheral nerve function following injury. This review discusses the progress we are making in translational peripheral neurobiology and our future directions.
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7104
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Abstract
Antidepressant pharmacotherapy is to date the most often used treatment for depression, but the exact mechanism of action underlying its therapeutic effect is still unclear. Many theories have been put forward to account for depression, as well as antidepressant activity, but none of them is exhaustive. Neuroimmune endocrine impairment is found in depressed patients; high levels of circulating corticosteroids along with hyperactivation of the immune system, high levels of proinflammatory cytokines, low levels of melatonin in plasma and urine, and disentrainment of circadian rhythms have been demonstrated. Moreover, antidepressant treatment seems to correct or at least to interfere with these alterations. In this review, we summarize the complex neuroimmune endocrine and chronobiological alterations found in patients with depression and how these systems interact with each other. We also explain how antidepressant therapy can modify these systems, along with some possible mechanisms of action shown in animal and human models.
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Affiliation(s)
- Marco Antonioli
- Psychoimmunology Translational Laboratory, Health Science Research Centre, Roehampton University, London, UK
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7105
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Ratelade J, Bennett JL, Verkman AS. Evidence against cellular internalization in vivo of NMO-IgG, aquaporin-4, and excitatory amino acid transporter 2 in neuromyelitis optica. J Biol Chem 2011; 286:45156-64. [PMID: 22069320 PMCID: PMC3247969 DOI: 10.1074/jbc.m111.297275] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 11/05/2011] [Indexed: 11/06/2022] Open
Abstract
Autoantibodies against astrocyte water channel aquaporin-4 (AQP4) are thought to be pathogenic in neuromyelitis optica (NMO). Prior work has suggested that a key component of NMO autoantibody (NMO-IgG) pathogenesis is internalization of AQP4 and the associated glutamate transporter EAAT2, leading to glutamate excitotoxicity. Here, we show selective endocytosis of NMO-IgG and AQP4 in transfected cell cultures, but little internalization in brain in vivo. AQP4-dependent endocytosis of NMO-IgG occurred rapidly in various AQP4-transfected cell lines, with efficient transport from early endosomes to lysosomes. Cell surface AQP4 was also reduced following NMO-IgG exposure. However, little or no internalization of NMO-IgG, AQP4, or EAAT2 was found in primary astrocyte cultures, nor was glutamate uptake affected by NMO-IgG exposure. Following injection of NMO-IgG into mouse brain, NMO-IgG binding and AQP4 expression showed a perivascular astrocyte distribution, without detectable cellular internalization over 24 h. We conclude that astrocyte endocytosis of NMO-IgG, AQP4, and EAAT2 is not a significant consequence of AQP4 autoantibody in vivo, challenging generally accepted views about NMO pathogenesis.
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Affiliation(s)
- Julien Ratelade
- From the Departments of Medicine and Physiology, University of California, San Francisco, California 94143 and
| | - Jeffrey L. Bennett
- the Departments of Neurology and Ophthalmology, University of Colorado Denver, Aurora, Colorado 80045
| | - A. S. Verkman
- From the Departments of Medicine and Physiology, University of California, San Francisco, California 94143 and
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7106
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Abstract
The foundations of innate immunity in neurodegenerative disorders were first laid by Del Rio Hortega (1919). He identified and named microglia, recognizing them as cells of mesodermal origin. Van Furth in 1969 elaborated the monocyte phagocytic system with microglia as the brain representatives. Validation of these concepts did not occur until 1987 when HLA-DR was identified on activated microglia in a spectrum of neurological disorders. HLA-DR had already been established as a definitive marker of immunocompetent cells of mesodermal origin. It was soon determined that the observed inflammatory reaction was an innate immune response. A rapid expansion of the field took place as other markers of an innate immune response were found that were made by neurons, astrocytes, oligodendroglia, and endothelial cells. The molecules included complement proteins and their regulators, inflammatory cytokines, chemokines, acute phase reactants, prostaglandins, proteases, protease inhibitors, coagulation factors, fibrinolytic factors, anaphylatoxins, integrins, free radical generators, and other unidentified neurotoxins. The Nimmerjahn movies demonstrated that resting microglia were constantly active, sampling the surround, and responding rapidly to brain damage. Ways of reducing the neurotoxic innate immune response and stimulating a healing response continue to be sought as a means for ameliorating the pathology in a spectrum of chronic degenerative disorders.
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Affiliation(s)
- Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, University of British Columbia Vancouver, BC, Canada
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7107
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Costello DA, Lyons A, Denieffe S, Browne TC, Cox FF, Lynch MA. Long term potentiation is impaired in membrane glycoprotein CD200-deficient mice: a role for Toll-like receptor activation. J Biol Chem 2011; 286:34722-32. [PMID: 21835925 PMCID: PMC3186410 DOI: 10.1074/jbc.m111.280826] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Indexed: 12/26/2022] Open
Abstract
The membrane glycoprotein CD200 is expressed on several cell types, including neurons, whereas expression of its receptor, CD200R, is restricted principally to cells of the myeloid lineage, including microglia. The interaction between CD200 and CD200R maintains microglia and macrophages in a quiescent state; therefore, CD200-deficient mice express an inflammatory phenotype exhibiting increased macrophage or microglial activation in models of arthritis, encephalitis, and uveoretinitis. Here, we report that lipopolysaccharide (LPS) and Pam(3)CysSerLys(4) exerted more profound effects on release of the proinflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNFα), in glia prepared from CD200(-/-) mice compared with wild type mice. This effect is explained by the loss of CD200 on astrocytes, which modulates microglial activation. Expression of Toll-like receptors 4 and 2 (TLR4 and -2) was increased in glia prepared from CD200(-/-) mice, and the evidence indicates that microglial activation, assessed by the increased numbers of CD11b(+) cells that stained positively for both MHCII and CD40, was enhanced in CD200(-/-) mice compared with wild type mice. These neuroinflammatory changes were associated with impaired long term potentiation (LTP) in CA1 of hippocampal slices prepared from CD200(-/-) mice. One possible explanation for this is the increase in TNFα in hippocampal tissue prepared from CD200(-/-) mice because TNFα application inhibited LTP in CA1. Significantly, LPS and Pam(3)CysSerLys(4), at concentrations that did not affect LTP in wild type mice, inhibited LTP in slices prepared from CD200(-/-) mice, probably due to the accompanying increase in TLR2 and TLR4. Thus, the neuroinflammatory changes that result from CD200 deficiency have a negative impact on synaptic plasticity.
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Affiliation(s)
- Derek A Costello
- Department of Physiology and the Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
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7108
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Fonken LK, Xu X, Weil ZM, Chen G, Sun Q, Rajagopalan S, Nelson RJ. Air pollution impairs cognition, provokes depressive-like behaviors and alters hippocampal cytokine expression and morphology. Mol Psychiatry 2011; 16:987-95, 973. [PMID: 21727897 DOI: 10.1038/mp.2011.76] [Citation(s) in RCA: 265] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Particulate matter air pollution is a pervasive global risk factor implicated in the genesis of pulmonary and cardiovascular disease. Although the effects of prolonged exposure to air pollution are well characterized with respect to pulmonary and cardiovascular function, comparatively little is known about the impact of particulate matter on affective and cognitive processes. The central nervous system may be adversely affected by activation of reactive oxygen species and pro-inflammatory pathways that accompany particulate matter pollution. Thus, we investigated whether long-term exposure to ambient fine airborne particulate matter (<2.5 μm (PM(2.5))) affects cognition, affective responses, hippocampal inflammatory cytokines and neuronal morphology. Male mice were exposed to either PM(2.5) or filtered air (FA) for 10 months. PM(2.5) mice displayed more depressive-like responses and impairments in spatial learning and memory as compared with mice exposed to FA. Hippocampal pro-inflammatory cytokine expression was elevated among PM(2.5) mice. Apical dendritic spine density and dendritic branching were decreased in the hippocampal CA1 and CA3 regions, respectively, of PM(2.5) mice. Taken together, these data suggest that long-term exposure to particulate air pollution levels typical of exposure in major cities around the globe can alter affective responses and impair cognition.
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7109
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Abstract
Humans are exposed to nanoparticles (NPs; diameter < 100 nm) from ambient air and certain workplaces. There are two main types of NPs; combustion-derived NPs (e.g., particulate matters, diesel exhaust particles, welding fumes) and manufactured or engineered NPs (e.g., titanium dioxide, carbon black, carbon nanotubes, silver, zinc oxide, copper oxide). Recently, there have been increasing reports indicating that inhaled NPs can reach the brain and may be associated with neurodegeneration. It is necessary to evaluate the potential toxic effects of NPs on brain because most of the neurobehavioral disorders may be of environmental origin. This review highlights studies on both combustion-derived NP- and manufactured or engineered NP-induced neuroinflammation, oxidative stress, and gene expression, as well as the possible mechanism of these effects in animal models and in humans.
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7110
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Turkman N, Shavrin A, Ivanov RA, Rabinovich B, Volgin A, Gelovani JG, Alauddin MM. Fluorinated cannabinoid CB2 receptor ligands: synthesis and in vitro binding characteristics of 2-oxoquinoline derivatives. Bioorg Med Chem 2011; 19:5698-707. [PMID: 21872477 PMCID: PMC3174488 DOI: 10.1016/j.bmc.2011.07.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 06/28/2011] [Accepted: 07/04/2011] [Indexed: 10/17/2022]
Abstract
Cannabinoid receptor 2 (CB2) plays an important role in human physiology and the pathophysiology of different diseases, including neuroinflammation, neurodegeneration, and cancer. Several classes of CB2 receptor ligands, including 2-oxoquinoline derivatives, have been previously reported. We report the synthesis and results of in vitro receptor binding of a focused library of new fluorinated 2-oxoquinoline CB2 ligands. Twelve compounds, 13-1618, 19, 21-24, 27, and 28 were synthesized in good yields in multiple steps. Human U87 glioma cells expressing either hCB1 (control) or hCB2 were generated via lentiviral transduction. In vitro competitive binding assay was performed using [(3)H]CP-55,940 in U87hCB1 and U87hCB2 cells. Inhibition constant (K(i)) values of compounds 13-16, 18, 19, 21-24, 27, and 28 for CB2 were >10,000, 2.8, 5.0, 2.4, 22, 0.8, 1.4, >10,000, 486, 58, 620, and 2400 nM, respectively, and those for CB1 were >10,000 nM. Preliminary in vitro results suggest that six of these compounds may be useful for therapy of neuropathic pain, neuroinflammatory diseases and immune disorders. In addition, compound 19, with its subnanomolar K(i) value, could be radiolabeled with (18)F and explored for PET imaging of CB2 expression.
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MESH Headings
- Binding, Competitive/drug effects
- Cell Line, Tumor
- Dose-Response Relationship, Drug
- Glioma/metabolism
- Glioma/pathology
- Humans
- Ligands
- Molecular Structure
- Quinolones/chemical synthesis
- Quinolones/chemistry
- Quinolones/pharmacology
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/biosynthesis
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/biosynthesis
- Stereoisomerism
- Structure-Activity Relationship
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Affiliation(s)
- Nashaat Turkman
- Department of Experimental Diagnostic Imaging, The University of Texas, M D Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA
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7111
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DeSalvo MK, Mayer N, Mayer F, Bainton RJ. Physiologic and anatomic characterization of the brain surface glia barrier of Drosophila. Glia 2011; 59:1322-40. [PMID: 21351158 PMCID: PMC3130812 DOI: 10.1002/glia.21147] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 12/20/2010] [Indexed: 12/22/2022]
Abstract
Central nervous system (CNS) physiology requires special chemical, metabolic, and cellular privileges for normal function, and blood-brain barrier (BBB) structures are the anatomic and physiologic constructs that arbitrate communication between the brain and body. In the vertebrate BBB, two primary cell types create CNS exclusion biology, a polarized vascular endothelium (VE), and a tightly associated single layer of astrocytic glia (AG). Examples of direct action by the BBB in CNS disease are constantly expanding, including key pathophysiologic roles in multiple sclerosis, stroke, and cancer. In addition, its role as a pharmacologic treatment obstacle to the brain is long standing; thus, molecular model systems that can parse BBB functions and understand the complex integration of sophisticated cellular anatomy and highly polarized chemical protection physiology are desperately needed. Compound barrier structures that use two primary cell types (i.e., functional bicellularity) are common to other humoral/CNS barrier structures. For example, invertebrates use two cell layers of glia, perineurial and subperineurial, to control chemical access to the brain, and analogous glial layers, fenestrated and pseudocartridge, to maintain the blood-eye barrier. In this article, we summarize our current understanding of brain-barrier glial anatomy in Drosophila, demonstrate the power of live imaging as a screening methodology for identifying physiologic characteristics of BBB glia, and compare the physiologies of Drosophila barrier layers to the VE/AG interface of vertebrates. We conclude that many unique BBB physiologies are conserved across phyla and suggest new methods for modeling CNS physiology and disease.
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Affiliation(s)
- Michael K. DeSalvo
- University of California at San Francisco, Department of Anesthesia and Perioperative Care, Program in Biological Sciences, Mission Bay Genentech Hall, 600 16th Street, San Francisco, CA 94158-2517
| | - Nasima Mayer
- University of California at San Francisco, Department of Anesthesia and Perioperative Care, Program in Biological Sciences, Mission Bay Genentech Hall, 600 16th Street, San Francisco, CA 94158-2517
| | - Fahima Mayer
- University of California at San Francisco, Department of Anesthesia and Perioperative Care, Program in Biological Sciences, Mission Bay Genentech Hall, 600 16th Street, San Francisco, CA 94158-2517
| | - Roland J. Bainton
- University of California at San Francisco, Department of Anesthesia and Perioperative Care, Program in Biological Sciences, Mission Bay Genentech Hall, 600 16th Street, San Francisco, CA 94158-2517
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7112
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Choudhury ME, Sugimoto K, Kubo M, Nagai M, Nomoto M, Takahashi H, Yano H, Tanaka J. A cytokine mixture of GM-CSF and IL-3 that induces a neuroprotective phenotype of microglia leading to amelioration of (6-OHDA)-induced Parkinsonism of rats. Brain Behav 2011; 1:26-43. [PMID: 22398979 PMCID: PMC3217672 DOI: 10.1002/brb3.11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 06/02/2011] [Accepted: 06/16/2011] [Indexed: 01/09/2023] Open
Abstract
Dopamine (DA) agonists are widely used as primary treatments for Parkinson's disease. However, they do not prevent progressive degeneration of dopaminergic neurons, the central pathology of the disease. In this study, we found that subcutaneous injection of a cytokine mixture containing granulocyte macrophage colony-stimulating factor and interleukin-3 (IL-3) markedly suppressed dopaminergic neurodegeneration in 6-hydroxydopamine-lesioned rats, an animal model of Parkinson's disease. The cytokine mixture suppressed the decrease of DA content in the striatum, and ameliorated motor function in the lesioned rats. In response to the cytokine injection, dopaminergic neurons in the substantia nigra pars compacta increased expression of the antiapoptotic protein Bcl-xL. Microglial activation in the pars compacta was evident in both the saline- and cytokine-injected rats. However, the cytokine mixture suppressed expression of the proinflammatory cytokines IL-1β and tumor necrosis factors α, and upregulated the neuroprotective factors insulin-like growth factor-1 and hepatocyte growth factor. Similar responses were observed in cultured microglia. Detailed morphometric analyses revealed that NG2 proteoglycan-expressing glial cells increased in the cytokine-injected rats, while astrocytic activation with increased expression of antioxidative factors was evident only in the saline-injected rats. Thus, the present findings show that the cytokine mixture was markedly effective in suppressing neurodegeneration. Its neuroprotective effects may be mediated by increased expression of Bcl-xL in dopaminergic neurons, and the activation of beneficial actions of microglia that promote neuronal survival. Furthermore, this cytokine mixture may have indirect actions on NG2 proteoglycan-expressing glia, whose role may be implicated in neuronal survival.
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Affiliation(s)
| | - Kana Sugimoto
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
- Department of Basic and Clinical Neuroscience, Ehime Proteo‐Medicine Research Center, Ehime University, Toon, Ehime, Japan
| | - Madoka Kubo
- Department of Therapeutic Medicine, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Masahiro Nagai
- Department of Therapeutic Medicine, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Masahiro Nomoto
- Department of Therapeutic Medicine, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Hisaaki Takahashi
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
- Department of Basic and Clinical Neuroscience, Ehime Proteo‐Medicine Research Center, Ehime University, Toon, Ehime, Japan
| | - Hajime Yano
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
- Department of Basic and Clinical Neuroscience, Ehime Proteo‐Medicine Research Center, Ehime University, Toon, Ehime, Japan
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
- Department of Basic and Clinical Neuroscience, Ehime Proteo‐Medicine Research Center, Ehime University, Toon, Ehime, Japan
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7113
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Gaudet AD, Popovich PG, Ramer MS. Wallerian degeneration: gaining perspective on inflammatory events after peripheral nerve injury. J Neuroinflammation 2011; 8:110. [PMID: 21878126 PMCID: PMC3180276 DOI: 10.1186/1742-2094-8-110] [Citation(s) in RCA: 546] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/30/2011] [Indexed: 01/15/2023] Open
Abstract
In this review, we first provide a brief historical perspective, discussing how peripheral nerve injury (PNI) may have caused World War I. We then consider the initiation, progression, and resolution of the cellular inflammatory response after PNI, before comparing the PNI inflammatory response with that induced by spinal cord injury (SCI).In contrast with central nervous system (CNS) axons, those in the periphery have the remarkable ability to regenerate after injury. Nevertheless, peripheral nervous system (PNS) axon regrowth is hampered by nerve gaps created by injury. In addition, the growth-supportive milieu of PNS axons is not sustained over time, precluding long-distance regeneration. Therefore, studying PNI could be instructive for both improving PNS regeneration and recovery after CNS injury. In addition to requiring a robust regenerative response from the injured neuron itself, successful axon regeneration is dependent on the coordinated efforts of non-neuronal cells which release extracellular matrix molecules, cytokines, and growth factors that support axon regrowth. The inflammatory response is initiated by axonal disintegration in the distal nerve stump: this causes blood-nerve barrier permeabilization and activates nearby Schwann cells and resident macrophages via receptors sensitive to tissue damage. Denervated Schwann cells respond to injury by shedding myelin, proliferating, phagocytosing debris, and releasing cytokines that recruit blood-borne monocytes/macrophages. Macrophages take over the bulk of phagocytosis within days of PNI, before exiting the nerve by the circulation once remyelination has occurred. The efficacy of the PNS inflammatory response (although transient) stands in stark contrast with that of the CNS, where the response of nearby cells is associated with inhibitory scar formation, quiescence, and degeneration/apoptosis. Rather than efficiently removing debris before resolving the inflammatory response as in other tissues, macrophages infiltrating the CNS exacerbate cell death and damage by releasing toxic pro-inflammatory mediators over an extended period of time. Future research will help determine how to manipulate PNS and CNS inflammatory responses in order to improve tissue repair and functional recovery.
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Affiliation(s)
- Andrew D Gaudet
- Department of Neuroscience and Center for Brain and Spinal Cord Repair, College of Medicine, The Ohio State University, 770 Biomedical Research Tower, 460 West 12th Ave, Columbus, OH, 43210, USA
- International Collaboration On Repair Discoveries (ICORD), Vancouver Coastal Health Research Institute, and Department of Zoology, University of British Columbia, 818 West 10th Ave, Vancouver, BC, V5T 1M9, Canada
| | - Phillip G Popovich
- Department of Neuroscience and Center for Brain and Spinal Cord Repair, College of Medicine, The Ohio State University, 770 Biomedical Research Tower, 460 West 12th Ave, Columbus, OH, 43210, USA
| | - Matt S Ramer
- International Collaboration On Repair Discoveries (ICORD), Vancouver Coastal Health Research Institute, and Department of Zoology, University of British Columbia, 818 West 10th Ave, Vancouver, BC, V5T 1M9, Canada
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7114
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Furr SR, Chauhan VS, Moerdyk-Schauwecker MJ, Marriott I. A role for DNA-dependent activator of interferon regulatory factor in the recognition of herpes simplex virus type 1 by glial cells. J Neuroinflammation 2011; 8:99. [PMID: 21838860 PMCID: PMC3168419 DOI: 10.1186/1742-2094-8-99] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 08/12/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The rapid onset of potentially lethal neuroinflammation is a defining feature of viral encephalitis. Microglia and astrocytes are likely to play a significant role in viral encephalitis pathophysiology as they are ideally positioned to respond to invading central nervous system (CNS) pathogens by producing key inflammatory mediators. Recently, DNA-dependent activator of IFN regulatory factor (DAI) has been reported to function as an intracellular sensor for DNA viruses. To date, the expression and functional role of DAI in the inflammatory responses of resident CNS cells to neurotropic DNA viruses has not been reported. METHODS Expression of DAI and its downstream effector molecules was determined in C57BL/6-derived microglia and astrocytes, either at rest or following exposure to herpes simplex virus type 1 (HSV-1) and/or murine gammaherpesvirus-68 (MHV-68), by immunoblot analysis. In addition, such expression was studied in ex vivo microglia/macrophages and astrocytes from uninfected animals or mice infected with HSV-1. Inflammatory cytokine production by glial cultures following transfection with a DAI specific ligand (B-DNA), or following HSV-1 challenge in the absence or presence of siRNA directed against DAI, was assessed by specific capture ELISA. The production of soluble neurotoxic mediators by HSV-1 infected glia following DAI knockdown was assessed by analysis of the susceptibility of neuron-like cells to conditioned glial media. RESULTS We show that isolated microglia and astrocytes constitutively express DAI and its effector molecules, and show that such expression is upregulated following DNA virus challenge. We demonstrate that these resident CNS cells express DAI in situ, and show that its expression is similarly elevated in a murine model of HSV-1 encephalitis. Importantly, we show B-DNA transfection can elicit inflammatory cytokine production by isolated glial cells and DAI knockdown can significantly reduce microglial and astrocyte responses to HSV-1. Finally, we demonstrate that HSV-1 challenged microglia and astrocytes release neurotoxic mediators and show that such production is significantly attenuated following DAI knockdown. CONCLUSIONS The functional expression of DAI by microglia and astrocytes may represent an important innate immune mechanism underlying the rapid and potentially lethal inflammation associated with neurotropic DNA virus infection.
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MESH Headings
- Animals
- Astrocytes/cytology
- Astrocytes/metabolism
- Astrocytes/virology
- Cell Death
- Cells, Cultured
- DNA, B-Form/chemistry
- DNA, B-Form/metabolism
- Encephalitis, Viral/immunology
- Encephalitis, Viral/physiopathology
- Encephalitis, Viral/virology
- Female
- Herpesvirus 1, Human/immunology
- Humans
- Immunity, Innate/immunology
- Interferon Regulatory Factors/genetics
- Interferon Regulatory Factors/metabolism
- Interleukin-6/immunology
- Mice
- Mice, Inbred C57BL
- Microglia/cytology
- Microglia/metabolism
- Microglia/virology
- Neurons/pathology
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Tumor Necrosis Factor-alpha/immunology
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Affiliation(s)
- Samantha R Furr
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Vinita S Chauhan
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | | | - Ian Marriott
- Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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7115
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Funk JA, Gohlke J, Kraft AD, McPherson CA, Collins JB, Harry GJ. Voluntary exercise protects hippocampal neurons from trimethyltin injury: possible role of interleukin-6 to modulate tumor necrosis factor receptor-mediated neurotoxicity. Brain Behav Immun 2011; 25:1063-77. [PMID: 21435392 PMCID: PMC3138904 DOI: 10.1016/j.bbi.2011.03.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 03/16/2011] [Accepted: 03/16/2011] [Indexed: 01/02/2023] Open
Abstract
In the periphery, exercise induces interleukin (IL)-6 to downregulate tumor necrosis factor (TNF), elevate interleukin-1 receptor antagonist (IL-1RA), decreasing inflammation. Exercise also offers neuroprotection and facilitates brain repair. IL-6 production in the hippocampus following exercise suggests the potential of a similar protective role as in the periphery to down-regulate TNFα and inflammation. Using a chemical-induced model of hippocampal dentate granule cell death (trimethyltin, TMT 2.4 mg/kg, ip) dependent upon TNF receptor signaling, we demonstrate neuroprotection in mice with 2 weeks access to running wheel. Exercise attenuated neuronal death and diminished elevations in TNFα, TNF receptor 1, myeloid differentiation primary response gene (MyD) 88, transforming growth factor β, chemokine (C-C motif) ligand 2 (CCL2), and CCL3. Elevated mRNA levels for IL-1α, IL-1RA, occurred with injury and protection. mRNA and protein levels of IL-6 and neuronal expression of IL-6 receptor α, were elevated with injury and protection. Microarray pathway analysis supported an up-regulation of TNFα cell death signaling pathways with TMT and inhibition by exercise. IL-6 pathway recruitment occurred in both conditions. IL-6 downstream signal events differed in the level of STAT3 activation. Exercise did not increase mRNA levels of brain derived neurotrophic factor, nerve growth factor, or glial derived neurotrophic factor. In IL-6 deficient mice, exercise did not attenuate TMT-induced tremor and a diminished level of neuroprotection was observed. These data suggest a contributory role for IL-6 induced by exercise for neuroprotection in the CNS similar to that seen in the periphery.
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Affiliation(s)
- Jason A. Funk
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC
| | - Julia Gohlke
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC,Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL
| | - Andrew D. Kraft
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC
| | - Christopher A. McPherson
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC
| | - Jennifer B. Collins
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC
| | - G. Jean Harry
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Dept of Health and Human Services, Research Triangle Park, NC,corresponding author: G. Jean Harry, National Institute of Environmental Health Sciences, P.O. Box 12233, MD C1-04, Research Triangle Park, NC 27709. Ph. (919) 541-0927, Fax. (919) 541-4634,
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7116
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Levesque S, Taetzsch T, Lull ME, Kodavanti U, Stadler K, Wagner A, Johnson JA, Duke L, Kodavanti P, Surace MJ, Block ML. Diesel exhaust activates and primes microglia: air pollution, neuroinflammation, and regulation of dopaminergic neurotoxicity. Environ Health Perspect 2011; 119:1149-55. [PMID: 21561831 PMCID: PMC3237351 DOI: 10.1289/ehp.1002986] [Citation(s) in RCA: 257] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 05/11/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Air pollution is linked to central nervous system disease, but the mechanisms responsible are poorly understood. OBJECTIVES Here, we sought to address the brain-region-specific effects of diesel exhaust (DE) and key cellular mechanisms underlying DE-induced microglia activation, neuroinflammation, and dopaminergic (DA) neurotoxicity. METHODS Rats were exposed to DE (2.0, 0.5, and 0 mg/m3) by inhalation over 4 weeks or as a single intratracheal administration of DE particles (DEP; 20 mg/kg). Primary neuron-glia cultures and the HAPI (highly aggressively proliferating immortalized) microglial cell line were used to explore cellular mechanisms. RESULTS Rats exposed to DE by inhalation demonstrated elevated levels of whole-brain IL-6 (interleukin-6) protein, nitrated proteins, and IBA-1 (ionized calcium-binding adaptor molecule 1) protein (microglial marker), indicating generalized neuroinflammation. Analysis by brain region revealed that DE increased TNFα (tumor necrosis factor-α), IL-1β, IL-6, MIP-1α (macrophage inflammatory protein-1α) RAGE (receptor for advanced glycation end products), fractalkine, and the IBA-1 microglial marker in most regions tested, with the midbrain showing the greatest DE response. Intratracheal administration of DEP increased microglial IBA-1 staining in the substantia nigra and elevated both serum and whole-brain TNFα at 6 hr posttreatment. Although DEP alone failed to cause the production of cytokines and chemokines, DEP (5 μg/mL) pretreatment followed by lipopolysaccharide (2.5 ng/mL) in vitro synergistically amplified nitric oxide production, TNFα release, and DA neurotoxicity. Pretreatment with fractalkine (50 pg/mL) in vitro ameliorated DEP (50 μg/mL)-induced microglial hydrogen peroxide production and DA neurotoxicity. CONCLUSIONS Together, these findings reveal complex, interacting mechanisms responsible for how air pollution may cause neuroinflammation and DA neurotoxicity.
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Affiliation(s)
- Shannon Levesque
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Campus, Richmond, Virginia, USA
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7117
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Kraft AD, Harry GJ. Features of microglia and neuroinflammation relevant to environmental exposure and neurotoxicity. Int J Environ Res Public Health 2011; 8:2980-3018. [PMID: 21845170 DOI: 10.3390/ijerph8072980] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/05/2011] [Accepted: 07/13/2011] [Indexed: 02/07/2023]
Abstract
Microglia are resident cells of the brain involved in regulatory processes critical for development, maintenance of the neural environment, injury and repair. They belong to the monocytic-macrophage lineage and serve as brain immune cells to orchestrate innate immune responses; however, they are distinct from other tissue macrophages due to their relatively quiescent phenotype and tight regulation by the CNS microenvironment. Microglia actively survey the surrounding parenchyma and respond rapidly to changes such that any disruption to neural architecture or function can contribute to the loss in regulation of the microglia phenotype. In many models of neurodegeneration and neurotoxicity, early events of synaptic degeneration and neuronal loss are accompanied by an inflammatory response including activation of microglia, perivascular monocytes, and recruitment of leukocytes. In culture, microglia have been shown to be capable of releasing several potentially cytotoxic substances, such as reactive oxygen intermediates, nitric oxide, proteases, arachidonic acid derivatives, excitatory amino acids, and cytokines; however, they also produce various neurotrophic factors and quench damage from free radicals and excitotoxins. As the primary source for pro-inflammatory cytokines, microglia are implicated as pivotal mediators of neuroinflammation and can induce or modulate a broad spectrum of cellular responses. Neuroinflammation should be considered as a balanced network of processes whereby subtle modifications can shift the cells toward disparate outcomes. For any evaluation of neuroinflammation and microglial responses, within the framework of neurotoxicity or degeneration, one key question in determining the consequence of neuroinflammation is whether the response is an initiating event or the consequence of tissue damage. As examples of environmental exposure-related neuroinflammation in the literature, we provide an evaluation of data on manganese and diesel exhaust particles.
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7118
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Wang X, Michaelis ML, Michaelis EK. Functional genomics of brain aging and Alzheimer's disease: focus on selective neuronal vulnerability. Curr Genomics 2011; 11:618-33. [PMID: 21629439 PMCID: PMC3078686 DOI: 10.2174/138920210793360943] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 10/05/2010] [Accepted: 10/21/2010] [Indexed: 01/02/2023] Open
Abstract
Pivotal brain functions, such as neurotransmission, cognition, and memory, decline with advancing age and, especially, in neurodegenerative conditions associated with aging, such as Alzheimer’s disease (AD). Yet, deterioration in structure and function of the nervous system during aging or in AD is not uniform throughout the brain. Selective neuronal vulnerability (SNV) is a general but sometimes overlooked characteristic of brain aging and AD. There is little known at the molecular level to account for the phenomenon of SNV. Functional genomic analyses, through unbiased whole genome expression studies, could lead to new insights into a complex process such as SNV. Genomic data generated using both human brain tissue and brains from animal models of aging and AD were analyzed in this review. Convergent trends that have emerged from these data sets were considered in identifying possible molecular and cellular pathways involved in SNV. It appears that during normal brain aging and in AD, neurons vulnerable to injury or cell death are characterized by significant decreases in the expression of genes related to mitochondrial metabolism and energy production. In AD, vulnerable neurons also exhibit down-regulation of genes related to synaptic neurotransmission and vesicular transport, cytoskeletal structure and function, and neurotrophic factor activity. A prominent category of genes that are up-regulated in AD are those related to inflammatory response and some components of calcium signaling. These genomic differences between sensitive and resistant neurons can now be used to explore the molecular underpinnings of previously suggested mechanisms of cell injury in aging and AD.
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Affiliation(s)
- Xinkun Wang
- Higuchi Biosciences Center and Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS 66047, USA
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7119
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Fields J, Gardner-Mercer J, Borgmann K, Clark I, Ghorpade A. CCAAT/enhancer binding protein β expression is increased in the brain during HIV-1-infection and contributes to regulation of astrocyte tissue inhibitor of metalloproteinase-1. J Neurochem 2011; 118:93-104. [PMID: 21281310 PMCID: PMC3112278 DOI: 10.1111/j.1471-4159.2011.07203.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human immunodeficiency virus (HIV)-1-associated neurocognitive disorders (HAND) associated with infection and activation of mononuclear phagocytes (MP) in the brain, occur late in disease. Infected/activated MP initiate neuroinflammation activating glial cells and ultimately disrupting neuronal function. Astrocytes secrete tissue inhibitor of metalloproteinase (TIMP)-1 in response to neural injury. Altered TIMP-1 levels are implicated in several CNS diseases. CCAAT enhancer-binding protein β (C/EBPβ), a transcription factor, is expressed in rodent brains in response to neuroinflammation, implicating it in Alzheimer's, Parkinson's, and HAND. Here, we report that C/EBPβ mRNA levels are elevated and its isoforms differentially expressed in total brain tissue lysates of HIV-1-infected and HIV-1 encephalitis patients. In vitro, HAND-relevant stimuli additively induce C/EBPβ nuclear expression in human astrocytes through 7 days of treatment. Over-expression of C/EBPβ increases TIMP-1 promoter activity, mRNA, and protein levels in human astrocytes activated with interleukin-1β. Knockdown of C/EBPβ with siRNA decreases TIMP-1 mRNA and protein levels. These data suggest that C/EBPβ isoforms are involved in complex regulation of astrocyte TIMP-1 production during HIV-1 infection; however, further studies are required to completely understand their role during disease progression.
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Affiliation(s)
- Jerel Fields
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107
| | | | - Kathleen Borgmann
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107
| | - Ian Clark
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
| | - Anuja Ghorpade
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107
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7120
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Ploix CC, Noor S, Crane J, Masek K, Carter W, Lo DD, Wilson EH, Carson MJ. CNS-derived CCL21 is both sufficient to drive homeostatic CD4+ T cell proliferation and necessary for efficient CD4+ T cell migration into the CNS parenchyma following Toxoplasma gondii infection. Brain Behav Immun 2011; 25:883-96. [PMID: 20868739 PMCID: PMC3032828 DOI: 10.1016/j.bbi.2010.09.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/16/2010] [Accepted: 09/16/2010] [Indexed: 12/29/2022] Open
Abstract
Injury, infection and autoimmune triggers increase CNS expression of the chemokine CCL21. Outside the CNS, CCL21 contributes to chronic inflammatory disease and autoimmunity by three mechanisms: recruitment of lymphocytes into injured or infected tissues, organization of inflammatory infiltrates into lymphoid-like structures and promotion of homeostatic CD4+ T-cell proliferation. To test if CCL21 plays the same role in CNS inflammation, we generated transgenic mice with astrocyte-driven expression of CCL21 (GFAP-CCL21 mice). Astrocyte-produced CCL21 was bioavailable and sufficient to support homeostatic CD4+ T-cell proliferation in cervical lymph nodes even in the absence of endogenous CCL19/CCL21. However, lymphocytes and glial-activation were not detected in the brains of uninfected GFAP-CCL21 mice, although CCL21 levels in GFAP-CCL21 brains were higher than levels expressed in inflamed Toxoplasma-infected non-transgenic brains. Following Toxoplasma infection, T-cell extravasation into submeningeal, perivascular and ventricular sites of infected CNS was not CCL21-dependent, occurring even in CCL19/CCL21-deficient mice. However, migration of extravasated CD4+, but not CD8+ T cells from extra-parenchymal CNS sites into the CNS parenchyma was CCL21-dependent. CD4+ T cells preferentially accumulated at perivascular, submeningeal and ventricular spaces in infected CCL21/CCL19-deficient mice. By contrast, greater numbers of CD4+ T cells infiltrated the parenchyma of infected GFAP-CCL21 mice than in wild-type or CCL19/CCL21-deficient mice. Together these data indicate that CCL21 expression within the CNS has the potential to contribute to T cell-mediated CNS pathology via: (a) homeostatic priming of CD4+ T-lymphocytes outside the CNS and (b) by facilitating CD4+ T-cell migration into parenchymal sites following pathogenic insults to the CNS.
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Affiliation(s)
| | - Shahani Noor
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, Graduate Program in Biomedical Sciences, University of California Riverside
| | - Janelle Crane
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside
| | - Kokoechat Masek
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside
| | - Whitney Carter
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside
| | - David D. Lo
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside
| | - Emma H. Wilson
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside,Correspondence should be directed to: Emma H. Wilson and Monica J. Carson, Division of Biomedical Sciences, University of California Riverside, 900 University Ave, Riverside, CA 92421, Tel: 951-827-2584, FAX: 951-827-5504, ,
| | - Monica J. Carson
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside,Correspondence should be directed to: Emma H. Wilson and Monica J. Carson, Division of Biomedical Sciences, University of California Riverside, 900 University Ave, Riverside, CA 92421, Tel: 951-827-2584, FAX: 951-827-5504, ,
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7121
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McPherson CA, Aoyama M, Harry GJ. Interleukin (IL)-1 and IL-6 regulation of neural progenitor cell proliferation with hippocampal injury: differential regulatory pathways in the subgranular zone (SGZ) of the adolescent and mature mouse brain. Brain Behav Immun 2011; 25:850-62. [PMID: 20833246 PMCID: PMC3033445 DOI: 10.1016/j.bbi.2010.09.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 09/03/2010] [Accepted: 09/06/2010] [Indexed: 12/13/2022] Open
Abstract
Current data suggests an association between elevations in interleukin 1 (IL-1)α, IL-1β, and IL-6 and the proliferation of neural progenitor cells (NPCs) following brain injury. A limited amount of work implicates changes in these pro-inflammatory responses with diminished NPC proliferation observed as a function of aging. In the current study, adolescent (21day-old) and 1year-old CD-1 male mice were injected with trimethyltin (TMT, 2.3mg/kg, i.p.) to produce acute apoptosis of hippocampal dentate granule cells. In this model, fewer 5-bromo-2'-deoxyuridine (BrdU)+ NPC were observed in both naive and injured adult hippocampus as compared to the corresponding number seen in adolescent mice. At 48h post-TMT, a similar level of neuronal death was observed across ages, yet activated ameboid microglia were observed in the adolescent and hypertrophic process-bearing microglia in the adult. IL-1α mRNA levels were elevated in the adolescent hippocampus; IL-6 mRNA levels were elevated in the adult. In subgranular zone (SGZ) isolated by laser-capture microdissection, IL-1β was detected but not elevated by TMT, IL-1a was elevated at both ages, while IL-6 was elevated only in the adult. Naïve NPCs isolated from the hippocampus expressed transcripts for IL-1R1, IL-6Rα, and gp130 with significantly higher levels of IL-6Rα mRNA in the adult. In vitro, IL-1α (150pg/ml) stimulated proliferation of adolescent NPCs; IL-6 (10ng/ml) inhibited proliferation of adolescent and adult NPCs. Microarray analysis of SGZ post-TMT indicated a prominence of IL-1a/IL-1R1 signaling in the adolescent and IL-6/gp130 signaling in the adult.
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Affiliation(s)
- CA McPherson
- Neurotoxicology Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health
,Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - M Aoyama
- Neurotoxicology Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health
,Department of Molecular Neurobiology, Nagoya City University, Nagoya, Japan
| | - GJ Harry
- Neurotoxicology Group, Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health
,
Corresponding address: National Institute of Environmental Health Sciences, P.O. Box 12233, MD C1-04, Research Triangle Park, NC 27709. Ph. (919) 541-0927, Fax. (919) 541-4634,
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7122
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Kroenke MA, Segal BM. IL-23 modulated myelin-specific T cells induce EAE via an IFNγ driven, IL-17 independent pathway. Brain Behav Immun 2011; 25:932-7. [PMID: 20951792 PMCID: PMC3064959 DOI: 10.1016/j.bbi.2010.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 09/17/2010] [Accepted: 10/01/2010] [Indexed: 11/25/2022] Open
Abstract
Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyelinating disease of the central nervous system (CNS) mediated by myelin-reactive CD4(+) T cells. An unresolved issue that has important clinical implications concerns the cytokines produced by myelin-reactive T cells that determine their pathogenicity. Initially, IL-12 polarized, IFNγ producing Th1 cells were thought to be essential for the development of EAE. More recently, IL-23 polarized, IL-17 producing Th17 cells have been highlighted as critical encephalitogenic effectors. There is growing evidence that parallel autoimmune pathways can result in common clinical and histopathological endpoints. In the current study, we describe a form of EAE induced by the transfer of IL-23 modulated CD4(+) T cells into IL-17 receptor (IL-17R) deficient hosts. We found that IL-23 stimulates myelin-reactive T cells to produce both IFNγ and IL-17. Surprisingly, in this model the development of EAE is IFNγ dependent. Our findings illustrate a novel mechanism by which IL-23 promotes encephalitogenicity and they further expand the spectrum of autoreactive T cells capable of mediating inflammatory demyelinating disease of the CNS.
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Affiliation(s)
- Mark A. Kroenke
- Holtom-Garrett Program in Neuroimmunology and Multiple Sclerosis Center, Department of Neurology, University of Michigan, Ann Arbor, MI 48109,Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Benjamin M. Segal
- Holtom-Garrett Program in Neuroimmunology and Multiple Sclerosis Center, Department of Neurology, University of Michigan, Ann Arbor, MI 48109
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7123
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Morgan TE, Davis DA, Iwata N, Tanner JA, Snyder D, Ning Z, Kam W, Hsu YT, Winkler JW, Chen JC, Petasis NA, Baudry M, Sioutas C, Finch CE. Glutamatergic neurons in rodent models respond to nanoscale particulate urban air pollutants in vivo and in vitro. Environ Health Perspect 2011; 119:1003-9. [PMID: 21724521 PMCID: PMC3222976 DOI: 10.1289/ehp.1002973] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 03/29/2011] [Indexed: 05/06/2023]
Abstract
BACKGROUND Inhalation of airborne particulate matter (PM) derived from urban traffic is associated with pathology in the arteries, heart, and lung; effects on brain are also indicated but are less documented. OBJECTIVE We evaluated rodent brain responses to urban nanoscale (< 200 nm) PM (nPM). METHODS Ambient nPM collected near an urban freeway was transferred to aqueous suspension and reaerosolized for 10-week inhalation exposure of mice or directly applied to rat brain cell cultures. RESULTS Free radicals were detected by electron paramagnetic resonance in the nPM 30 days after initial collection. Chronic inhalation of reaerosolized nPM altered selected neuronal and glial activities in mice. The neuronal glutamate receptor subunit (GluA1) was decreased in hippocampus, whereas glia were activated and inflammatory cytokines were induced [interleukin-1α (IL-1α), tumor necrosis factor-α (TNFα)] in cerebral cortex. Two in vitro models showed effects of nPM suspensions within 24-48 hr of exposure that involved glutamatergic functions. In hippocampal slice cultures, nPM increased the neurotoxicity of NMDA (N-methyl-d-aspartic acid), a glutamatergic agonist, which was in turn blocked by the NMDA antagonist AP5 [(2R)-amino-5-phosphonopentanoate]. In embryonic neuron cultures, nPM impaired neurite outgrowth, also blocked by AP5. Induction of IL-1α and TNFα in mixed glia cultures required higher nPM concentrations than did neuronal effects. Because conditioned media from nPM-exposed glia also impaired outgrowth of embryonic neurites, nPM can act indirectly, as well as directly, on neurons in vitro. CONCLUSIONS nPM can affect embryonic and adult neurons through glutamatergic mechanisms. The interactions of nPM with glutamatergic neuronal functions suggest that cerebral ischemia, which involves glutamatergic excitotoxicity, could be exacerbated by nPM.
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Affiliation(s)
- Todd E Morgan
- Davis School of Gerontology, University of Southern California, Los Angeles, California 90089, USA
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7124
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Choi BR, Kwon KJ, Park SH, Jeon WK, Han SH, Kim HY, Han JS. Alternations of Septal-hippocampal System in the Adult Wistar Rat with Spatial Memory Impairments Induced by Chronic Cerebral Hypoperfusion. Exp Neurobiol 2011; 20:92-9. [PMID: 22110366 PMCID: PMC3213701 DOI: 10.5607/en.2011.20.2.92] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/12/2011] [Indexed: 11/19/2022] Open
Abstract
In the current investigation, the status of the septo-hippocampal cholinergic pathway and hippocampal mitogen-activated protein kinase (MAPK) signaling was examined in male Wistar rats with chronic cerebral hypoperfusion, which showed cognitive deficits based on assessment on a version of the Morris water maze. Chronic cerebral hypoperfusion was induced by bilateral common artery occlusion and maintained for 12 weeks until behavioral testing. Chronic cerebral hypoperfusion was shown to induce memory impairments and microglial activation in regions of white matter, including the fimbria of hippocampus. Choline acetyltransferase expression of the basal forebrain and expression of hippocampal MAPKs was decreased in rats with BCCAo compared to control rats. The results of this study suggest that cognitive decline induced by chronic cerebral hypoperfusion could be related to dysfunction of the basal forebrain cholinergic system and reduction of hippocampal MAPK activities.
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Affiliation(s)
- Bo-Ryoung Choi
- Department of Biological Sciences & Center for Geriatric Neuroscience Research, IBST, Konkuk University, Seoul 143-701, Korea
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7125
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Bartels AL, Leenders KL. Cyclooxygenase and neuroinflammation in Parkinson's disease neurodegeneration. Curr Neuropharmacol 2011; 8:62-8. [PMID: 20808546 PMCID: PMC2866462 DOI: 10.2174/157015910790909485] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 09/21/2009] [Accepted: 11/02/2009] [Indexed: 01/07/2023] Open
Abstract
Cyclooxygenase (COX) expression in the brain is associated with pro-inflammatory activities, which are instrumental in neurodegenerative processes such as Parkinson’s disease (PD). It is discussed that drugs with the capacity to rescue dopaminergic neurons from microglia toxicity and neuroinflammatory processes may result in an amelioration of parkinsonian symptoms by delaying the onset or slowing progression. This article reviews the involvement of COX in neuroinflammation, specifically focussing at the role of selective COX-2 inhibition in neuroinflammation and neurodegeneration in Parkinson’s disease.
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Affiliation(s)
- Anna L Bartels
- Dept. of Neurology, University Medical Centre Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands.
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7126
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Bondy SC. Nanoparticles and colloids as contributing factors in neurodegenerative disease. Int J Environ Res Public Health 2011; 8:2200-11. [PMID: 21776226 PMCID: PMC3138021 DOI: 10.3390/ijerph8062200] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 05/13/2011] [Accepted: 05/16/2011] [Indexed: 11/16/2022]
Abstract
This review explores the processes underlying the deleterious effects of the presence of insoluble or colloidal depositions within the central nervous system. These materials are chemically unreactive and can have a prolonged residence in the brain. They can be composed of mineral or proteinaceous materials of intrinsic or exogenous origin. Such nanoparticulates and colloids are associated with a range of slow-progressing neurodegenerative states. The potential common basis of toxicity of these materials is discussed. A shared feature of these disorders involves the appearance of deleterious inflammatory changes in the CNS. This may be due to extended and ineffective immune responses. Another aspect is the presence of excess levels of reactive oxygen species within the brain. In addition with their induction by inflammatory events, these may be further heightened by the presence of redox active transition metals to the large surface area afforded by nanoparticles and amphipathic micelles.
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Affiliation(s)
- Stephen C Bondy
- Division of Occupational & Environmental Health, Department of Medicine, University of California, Irvine, Irvine, CA 92697, USA.
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7127
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Rosi S. Neuroinflammation and the plasticity-related immediate-early gene Arc. Brain Behav Immun 2011; 25 Suppl 1:S39-49. [PMID: 21320587 PMCID: PMC3098296 DOI: 10.1016/j.bbi.2011.02.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/07/2011] [Accepted: 02/07/2011] [Indexed: 12/01/2022] Open
Abstract
Neurons exist within a microenvironment that significantly influences their function and survival. While there are many environmental factors that can potentially impact neuronal function, activation of the innate immune system (microglia) is an important element common to many neurological and pathological conditions associated with memory loss. Learning and memory processes rely on the ability of neurons to alter their transcriptional programs in response to synaptic input. Recent advances in cell-based imaging of plasticity-related immediate-early gene (IEG) expression have provided a tool to investigate plasticity-related changes across multiple brain regions. The activity-regulated, cytoskeleton-associated IEG Arc is a regulator of protein synthesis-dependent forms of synaptic plasticity, which are essential for memory formation. Visualisation of Arc provides cellular level resolution for the mapping of neuronal networks. Chronic activation of the innate immune system alters Arc activity patterns, and this may be a mechanism by which it induces the cognitive dysfunction frequently associated with neuroinflammatory conditions. This review discusses the use of Arc expression during activation of the innate immune system as a valid marker of altered plasticity and a predictor of cognitive dysfunction.
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Affiliation(s)
- Susanna Rosi
- Brain and Spinal Injury Center, University of California San Francisco, San Francisco, CA 94110, USA.
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7128
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Frank MG, Watkins LR, Maier SF. Stress- and glucocorticoid-induced priming of neuroinflammatory responses: potential mechanisms of stress-induced vulnerability to drugs of abuse. Brain Behav Immun 2011; 25 Suppl 1:S21-8. [PMID: 21256955 DOI: 10.1016/j.bbi.2011.01.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/10/2011] [Accepted: 01/10/2011] [Indexed: 11/22/2022] Open
Abstract
Stress and stress-induced glucocorticoids (GCs) sensitize drug abuse behavior as well as the neuroinflammatory response to a subsequent pro-inflammatory challenge. Stress also predisposes or sensitizes individuals to develop substance abuse. There is an emerging evidence that glia and glia-derived neuroinflammatory mediators play key roles in the development of drug abuse. Drugs of abuse such as opioids, psychostimulants, and alcohol induce neuroinflammatory mediators such as pro-inflammatory cytokines (e.g. interleukin (IL)-1β), which modulate drug reward, dependence, and tolerance as well as analgesic properties. Drugs of abuse may directly activate microglial and astroglial cells via ligation of Toll-like receptors (TLRs), which mediate the innate immune response to pathogens as well as xenobiotic agents (e.g. drugs of abuse). The present review focuses on understanding the immunologic mechanism(s) whereby stress primes or sensitizes the neuroinflammatory response to drugs of abuse and explores whether stress- and GC-induced sensitization of neuroimmune processes predisposes individuals to drug abuse liability and the role of neuroinflammatory mediators in the development of drug addiction.
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7129
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Alikunju S, Muneer PA, Zhang Y, Szlachetka AM, Haorah J. The inflammatory footprints of alcohol-induced oxidative damage in neurovascular components. Brain Behav Immun 2011; 25 Suppl 1:S129-36. [PMID: 21262340 PMCID: PMC3098299 DOI: 10.1016/j.bbi.2011.01.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/13/2011] [Accepted: 01/14/2011] [Indexed: 01/21/2023] Open
Abstract
Microvessels, the main components of the blood-brain barrier (BBB) are vulnerable to oxidative damage during alcohol-induced stress. Alcohol produces oxidative damage within the vessels and in the brain. Using our animal model of catheter implant into the common carotid artery (CCA), we trace the footprints of alcohol-induced oxidative damage and inflammatory process at the BBB and into the brain. The uniqueness of the finding is that ethanol causes oxidative damage in all neurovascular components by activating NADPH oxidase and inducible nitric oxide synthase in the brain. It is not the oxidants but the ethanol that traverses through the BBB because we found that the highly reactive peroxynitrite does not cross the BBB. Thus, oxidative damage is caused at the site of oxidant production in the microvessels and in the brain. Our data indicate that acetaldehyde (the primary metabolite of ethanol) is the inducer/activator of these enzymes that generate oxidants in brain neurovascular cells. Evidence for alcohol-induced BBB damage is indicated by the alterations of the tight junction protein occludin in intact microvessels. Importantly, we demonstrate that the site of BBB oxidative damage is also the site of immune cells aggregation in the microvessels, which paves the path for inflammatory footprints. These findings reveal the underlying mechanisms that ethanol-elicited BBB oxidative damage initiates the brain vascular inflammatory process, which ultimately leads to neuroinflammation.
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Affiliation(s)
| | | | | | | | - James Haorah
- Corresponding author: James Haorah, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985215 Nebraska Medical Center, Omaha, NE 68198-5215, Phone: (402) 559-5406, Fax: (402) 559-8922,
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7130
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Persidsky Y, Ho W, Ramirez SH, Potula R, Abood ME, Unterwald E, Tuma R. HIV-1 infection and alcohol abuse: neurocognitive impairment, mechanisms of neurodegeneration and therapeutic interventions. Brain Behav Immun 2011; 25 Suppl 1:S61-70. [PMID: 21397004 PMCID: PMC3098312 DOI: 10.1016/j.bbi.2011.03.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/02/2011] [Accepted: 03/02/2011] [Indexed: 01/12/2023] Open
Abstract
Clinical studies indicate that alcohol dependence has an additive effect on cognitive deficits associated with HIV-1 infection. Findings in humans and animal models suggest that alcohol, similar to HIV-1, induces inflammatory processes in the brain leading to neurodegeneration. The causes of HIV-1-associated neurotoxicity are comparable to those mediating alcohol-induced neuronal injury. This review aims to present the mechanisms of the combined effects of HIV-1 and alcohol abuse in the brain and to discuss neuroprotective therapies. Oxidative stress, overproduction of pro-inflammatory factors, impairment of blood-brain barrier and glutamate associated neurotoxicity appear to play important roles in alcohol driven neurodegeneration. Diminution of neuroinflammation constitutes a logical approach for prevention of HIV-1 and alcohol mediated neurodegeneration. Agonists of cannabinoid receptor 2 (CB₂) possess potent anti-inflammatory and neuroprotective properties. We address multifaceted beneficial effects of CB₂ activation in the setting of HIV-1 brain infection and alcohol abuse.
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Affiliation(s)
- Yuri Persidsky
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
| | - Wenzhe Ho
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia PA
,Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia PA
| | - Servio H. Ramirez
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia PA
| | - Raghava Potula
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia PA
,Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia PA
| | - Mary E. Abood
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia PA
,Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia PA
| | - Ellen Unterwald
- Department of Pharmacology, Temple University School of Medicine, Philadelphia PA
,Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia PA
| | - Ronald Tuma
- Department of Physiology, Temple University School of Medicine, Philadelphia PA
,Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia PA
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7131
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Yakovleva T, Bazov I, Watanabe H, Hauser KF, Bakalkin G. Transcriptional control of maladaptive and protective responses in alcoholics: a role of the NF-κB system. Brain Behav Immun 2011; 25 Suppl 1:S29-38. [PMID: 21195164 PMCID: PMC3588165 DOI: 10.1016/j.bbi.2010.12.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/22/2010] [Accepted: 12/22/2010] [Indexed: 11/27/2022] Open
Abstract
Alcohol dependence and associated cognitive impairment appear to result from maladaptive neuroplasticity in response to chronic alcohol consumption, neuroinflammation and neurodegeneration. The inherent stability of behavioral alterations associated with the addicted state suggests that transcriptional and epigenetic mechanisms are operative. NF-κB transcription factors are regulators of synaptic plasticity and inflammation, and responsive to a variety of stimuli including alcohol. These factors are abundant in the brain where they have diverse functions that depend on the composition of the NF-κB complex and cellular context. In neuron cell bodies, NF-κB is constitutively active, and involved in neuronal injury and neuroprotection. However, at the synapse, NF-κB is present in a latent form and upon activation is transported to the cell nucleus. In glia, NF-κB is inducible and regulates inflammatory processes that exacerbate alcohol-induced neurodegeneration. Animal studies demonstrate that acute alcohol exposure transiently activates NF-κB, which induces neuroinflammatory responses and neurodegeneration. Postmortem studies of brains of human alcoholics suggest that repeated cycles of alcohol consumption and withdrawal cause adaptive changes in the NF-κB system that may permit the system to better tolerate excessive stimulation. This type of tolerance, ensuring a low degree of responsiveness to applied stimuli, apparently differs from that in the immune system, and may represent a compensatory response that protects brain cells against alcohol neurotoxicity. This view is supported by findings showing preferential downregulation of pro-apoptotic gene expression in the affected brain areas in human alcoholics. Although further verification is needed, we speculate that NF-κB-driven neuroinflammation and disruption to neuroplasticity play a significant role in regulating alcohol dependence and cognitive impairment.
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Affiliation(s)
- Tatjana Yakovleva
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Igor Bazov
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Hiroyuki Watanabe
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Kurt F. Hauser
- Department of Pharmacology & Toxicology, and Institute for Drug and Alcohol Studies, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA
| | - Georgy Bakalkin
- Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden,To whom correspondence may be addressed: Georgy Bakalkin, Division of Biological Research on Drug Dependence, Department of Pharmaceutical Biosciences, Uppsala University, Box 591, 751 24 Uppsala, Sweden, , Phone: (+46) 18 471 5050, Fax: (+046) 18-50 19 20
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7132
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McClain JA, Morris SA, Deeny MA, Marshall SA, Hayes DM, Kiser ZM, Nixon K. Adolescent binge alcohol exposure induces long-lasting partial activation of microglia. Brain Behav Immun 2011; 25 Suppl 1:S120-8. [PMID: 21262339 DOI: 10.1016/j.bbi.2011.01.006] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 01/12/2011] [Accepted: 01/14/2011] [Indexed: 12/30/2022] Open
Abstract
Accumulating evidence indicates that the adolescent hippocampus is highly susceptible to alcohol-induced structural damage and behavioral deficits. Microglia are vitally important brain constituents needed to support and maintain proper neural function; however, alcohol's effects on microglia have only recently gained attention. The microglial response to alcohol during adolescence has yet to be studied; therefore, we examined hippocampal microglial activation in an adolescence binge alcohol exposure model. Adolescent male Sprague-Dawley rats were administered ethanol 3 times/day for 4 days and were sacrificed 2, 7, and 30 days later. Bromo-deoxy-Uridine was injected 2 days after ethanol exposure to label dividing cells. Microglia morphology was scored using the microglia marker Iba-1, while the extent of microglial activation was examined with ED-1, major histocompatibility complex-II (MHC-II), and tumor necrosis factor (TNF)-α expression. Ethanol induced significant morphological change in hippocampal microglia, consistent with activation. In addition, ethanol increased the number of BrdU+ cells throughout all regions of the hippocampus 2 days after the last dose. Confocal microscopy showed that the proliferating BrdU+ cells in each region were Iba-1+ microglia. Importantly, newly born microglia survived and retained their morphological characteristics 30 days after ethanol exposure. Ethanol did not alter hippocampal ED-1, MHC-II, or TNF-α expression, suggesting that a single period of binge ethanol exposure does not induce a full microglial-driven neuroinflammatory response. These results establish that ethanol triggers partial microglial activation in the adolescent hippocampus that persists through early adulthood, suggesting that alcohol exposure during this unique developmental time period has long-lasting consequences.
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7133
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Tahanian E, Sanchez LA, Shiao TC, Roy R, Annabi B. Flavonoids targeting of IκB phosphorylation abrogates carcinogen-induced MMP-9 and COX-2 expression in human brain endothelial cells. Drug Des Devel Ther 2011; 5:299-309. [PMID: 21625419 PMCID: PMC3100225 DOI: 10.2147/dddt.s19931] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Indexed: 12/11/2022]
Abstract
Brain endothelial cells play an essential role as structural and functional components of the blood–brain barrier (BBB). Increased BBB breakdown and brain injury are associated with neuroinflammation and are thought to trigger mechanisms involving matrix metalloproteinase upregulation. Emerging evidence also indicates that cyclooxygenase (COX) inhibition limits BBB disruption, but the mechanisms linking metalloproteinase to COX remain unknown. In this study, we sought to investigate the nuclear factor-kappa B (NF-κB) signaling pathway, a common pathway in both the regulation of matrix metalloproteinase-9 (MMP-9) and COX-2 expression, and the inhibitory properties of several chemopreventive flavonoids. Human brain microvascular endothelial cells were treated with a combination of phorbol 12-myristate 13-acetate (PMA), a carcinogen documented to increase MMP-9 and COX-2 through NF-κB, and several naturally occurring flavonoids. Among the molecules tested, we found that fisetin, apigenin, and luteolin specifically and dose-dependently antagonized PMA-induced COX-2 and MMP-9 gene and protein expressions as assessed by qRT-PCR, immunoblotting, and zymography respectively. We further demonstrate that flavonoids impact on IκK-mediated phosphorylation activity as demonstrated by the inhibition of PMA-induced IκB phosphorylation levels. Our results suggest that BBB disruption during neuroinflammation could be pharmacologically reduced by a specific class of flavonoids acting as NF-κB signal transduction inhibitors.
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Affiliation(s)
- Elizabeth Tahanian
- Centre de Recherche BioMED, Département de chimie, Université du Québec à Montréal, QC, Canada
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7134
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Puntambekar SS, Davis DS, Hawel L, Crane J, Byus CV, Carson MJ. LPS-induced CCL2 expression and macrophage influx into the murine central nervous system is polyamine-dependent. Brain Behav Immun 2011; 25:629-39. [PMID: 21237263 PMCID: PMC3081407 DOI: 10.1016/j.bbi.2010.12.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/30/2010] [Accepted: 12/21/2010] [Indexed: 12/31/2022] Open
Abstract
Increased polyamine production is observed in a variety of chronic neuroinflammatory disorders, but in vitro and in vivo studies yield conflicting data on the immunomodulatory consequences of their production. Ornithine decarboxylase (ODC) is the rate-limiting enzyme in endogenous polyamine production. To identify the role of polyamine production in CNS-intrinsic inflammatory responses, we defined CNS sites of ODC expression and the consequences of inhibiting ODC in response to intracerebral injection of LPS±IFNγ. In situ hybridization analysis revealed that both neurons and non-neuronal cells rapidly respond to LPS±IFNγ by increasing ODC expression. Inhibiting ODC by co-injecting DFMO decreased LPS-induced CCL2 expression and macrophage influx into the CNS, without altering LPS-induced microglial or macrophage activation. Conversely, intracerebral injection of polyamines was sufficient to trigger macrophage influx into the CNS of wild-type but not CCL2KO mice, demonstrating the dependence of macrophage influx on CNS expression of CCL2. Consistent with these data, addition of putrescine and spermine to mixed glial cultures dramatically increased CCL2 expression and to a much lesser extent, TNF expression. Addition of all three polyamines to mixed glial cultures also decreased the numbers and percentages of oligodendrocytes present. However, in vivo, inhibiting the basal levels of polyamine production was sufficient to induce expression of apolipoprotein D, a marker of oxidative stress, within white matter tracts. Considered together, our data indicate that: (1) CNS-resident cells including neurons play active roles in recruiting pro-inflammatory TREM1-positive macrophages into the CNS via polyamine-dependent induction of CCL2 expression and (2) modulating polyamine production in vivo may be a difficult strategy to limit inflammation and promote repair due to the dual homeostatic and pro-inflammatory roles played by polyamines.
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Affiliation(s)
- Shweta S. Puntambekar
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA,Graduate Program in Cell, Molecular and Developmental Biology, University of California Riverside, USA
| | - Deirdre S. Davis
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA,Graduate Program in Biomedical Sciences, University of California Riverside, USA
| | - Leo Hawel
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA
| | - Janelle Crane
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA
| | - Craig V. Byus
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA
| | - Monica J. Carson
- Division of Biomedical Sciences, Center for Glial-Neuronal Interactions, University of California Riverside, USA,To whom correspondence should be addressed: Monica J Carson Division of Biomedical Sciences Center for Glial-Neuronal Interactions University of California Riverside 900 University Ave Riverside, CA 92521
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7135
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Frankola KA, Greig NH, Luo W, Tweedie D. Targeting TNF-α to elucidate and ameliorate neuroinflammation in neurodegenerative diseases. CNS Neurol Disord Drug Targets 2011; 10:391-403. [PMID: 21288189 PMCID: PMC4663975 DOI: 10.2174/187152711794653751] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 09/30/2010] [Indexed: 12/21/2022]
Abstract
Inflammatory signals generated within the brain and peripheral nervous system direct diverse biological processes. Key amongst the inflammatory molecules is tumor necrosis factor-α (TNF-α), a potent pro-inflammatory cytokine that, via binding to its associated receptors, is considered to be a master regulator of cellular cascades that control a number of diverse processes coupled to cell viability, gene expression, synaptic integrity and ion homeostasis. Whereas a self-limiting neuroinflammatory response generally results in the resolution of an intrinsically or extrinsically triggered insult by the elimination of toxic material or injured tissue to restore brain homeostasis and function, in the event of an unregulated reaction, where the immune response persists, inappropriate chronic neuroinflammation can ensue. Uncontrolled neuroinflammatory activity can induce cellular dysfunction and demise, and lead to a self-propagating cascade of harmful pathogenic events. Such chronic neuroinflammation is a typical feature across a range of debilitating common neurodegenerative diseases, epitomized by Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, in which TNF-α expression appears to be upregulated and may represent a valuable target for intervention. Elaboration of the protective homeostasis signaling cascades from the harmful pathogenic ones that likely drive disease onset and progression could aid in the clinical translation of approaches to lower brain and peripheral nervous system TNF-α levels, and amelioration of inappropriate neuroinflammation.
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Affiliation(s)
- Kathryn A. Frankola
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Nigel H. Greig
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Weiming Luo
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - David Tweedie
- Drug Design & Development Section, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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7136
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Zoppi S, Pérez Nievas BG, Madrigal JL, Manzanares J, Leza JC, García-Bueno B. Regulatory role of cannabinoid receptor 1 in stress-induced excitotoxicity and neuroinflammation. Neuropsychopharmacology 2011; 36:805-18. [PMID: 21150911 DOI: 10.1038/npp.2010.214] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exposure to stress elicits excitoxicity and neuroinflammation in the brain, contributing to cell death and damage in stress-related neurological and neuropsychiatric diseases. The endocannabinoid system is present in stress-responsive neural circuits and has been proposed as an endogenous neuroprotective system activated in some neuropathological scenarios to restore homeostasis. To elucidate the possible regulatory role of cannabinoid receptor 1 (CB1) in stress-induced excitotoxicity and neuroinflammation, both genetic and pharmacological approaches were used alternatively: (1) wild-type (WT) and CB1 knockout mice (CB1-KO) were exposed to immobilization/acoustic stress (2 h/day for 4 days) and (2) to specifically activate CB1, the selective CB1 agonist Arachidonyl-2'-chloroethylamide (ACEA) (2.5 mg/kg) was intraperitoneally administered daily to some groups of animals. Stress exposure increased CB1 mRNA and protein expression in the prefrontal cortex of WT mice in a mechanism related to N-methyl-D-aspartate glutamate receptor activation. Daily ACEA pretreatment prevented stress-induced: (1) upregulation of CB1 mRNA and protein, (2) decrease in glutamate uptake and glutamate astroglial transporter excitatory amino acid transporter 2 expression, (3) increase in consecutive proinflammatory molecules, such as cytokines (tumor necrosis factor-α and MCP-1), nuclear factor kappa B, and enzymatic sources, such as inducible nitric oxide synthase (NOS-2) and cyclooxygenase-2 (COX-2), (4) increase in lipid peroxidation; although having no effect on plasma corticosterone. Interestingly, a possible related mechanism could be the positive ACEA modulation of the antiinflammatory pathway deoxyprostaglandin/peroxisome proliferator-activated receptor γ (15d-PGJ(2)/PPARγ). Conversely, KO animal experiments indicated that a lack of CB1 produces hypothalamic/pituitary/adrenal (HPA) axis dysregulation and exacerbates stress-induced excitotoxic/neuroinflammatory responses. These multifaceted neuroprotective effects suggest that CB1 activation could be a new therapeutic strategy against neurological/neuropsychiatric pathologies with HPA axis dysregulation and an excitotoxic/neuroinflammatory component in their pathophysiology.
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7137
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Abstract
STUDY OBJECTIVES Sleep loss has pro-inflammatory effects, but the roles of specific cell populations in mediating these effects have not been delineated. We assessed the modulation of the electroencephalographic and molecular responses to sleep deprivation (S-DEP) by minocycline, a compound that attenuates microglial activation occurring in association with neuroinflammatory events. DESIGN Laboratory rodents were subjected to assessment of sleep and wake in baseline and sleep deprived conditions. PARTICIPANTS Adult male CD-1 mice (30-35 g) subjected to telemetric electroencephalography. INTERVENTIONS Minocycline was administered daily. Mice were subjected to baseline data collection on the first day of minocycline administration and, on subsequent days, 2 S-DEP sessions, 1 and 3 h in duration, followed by recovery sleep. Following EEG studies, mice were euthanized either at the end of a 3 h S-DEP or as time-of day controls for sampling of brain messenger RNAs. Gene expression was measured by real-time polymerase chain reaction. MEASUREMENTS AND RESULTS Minocycline-treated mice exhibited a reduction in time spent asleep, relative to saline-treated mice, in the 3-h interval immediately after administration. S-DEP resulted in an increase in EEG slow wave activity relative to baseline in saline-treated mice. This response to S-DEP was abolished in animals subjected to chronic minocycline administration. S-DEP suppressed the expression of the microglial-specific transcript cd11b and the neuroinflammation marker peripheral benzodiazepine receptor, in the brain at the mRNA level. Minocycline attenuated the elevation of c-fos expression by S-DEP. Brain levels of pro-inflammatory cytokine mRNAs interleukin-1β (il-1β), interleukin-6 (il-6), and tumor necrosis factor-α (tnfα) were unaffected by S-DEP, but were elevated in minocycline-treated mice relative to saline-treated mice. CONCLUSIONS The anti-neuroinflammatory agent minocycline prevents either the buildup or expression of sleep need in rodents. The molecular mechanism underlying this effect is not known, but it is not mediated by suppression of il-1β, il-6, and tnfα at the transcript level.
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Affiliation(s)
- Jonathan P Wisor
- WWAMI Medical Education Program and Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Spokane, WA, USA.
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7138
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Miller JA, Trout BR, Sullivan KA, Bialecki RA, Roberts RA, Tjalkens RB. Low-dose 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine causes inflammatory activation of astrocytes in nuclear factor-κB reporter mice prior to loss of dopaminergic neurons. J Neurosci Res 2011; 89:406-17. [PMID: 21259327 PMCID: PMC6487665 DOI: 10.1002/jnr.22549] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 10/08/2010] [Accepted: 10/11/2010] [Indexed: 01/07/2023]
Abstract
Neuroinflammation is implicated in the progression of numerous disease states of the CNS, but early inflammatory signaling events in glial cells that may predispose neurons to injury are not easily characterized in vivo. To address this question, we exposed transgenic mice expressing a nuclear factor-κB (NF-κB)-driven enhanced green fluorescent protein (EGFP) reporter construct to low doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and examined inflammatory activation of astrocytes in relation to neurobehavioral and neuropathological outcomes. The highest dose of MPTP (60 mg/kg total dose) caused a decrease in locomotor activity and a reduction in stride length. No significant loss of dopaminergic neurons in the substantia nigra was apparent at any dose. In contrast, expression of tyrosine hydroxylase in striatal fibers was reduced at 60 mg/kg MPTP, as were levels of dopamine and DOPAC. Colocalized expression of EGFP and inducible nitric oxide synthase (NOS2) occurred in astrocytes at 30 and 60 mg/kg MPTP and was associated with increased protein nitration in nigral dopaminergic neurons. Inhibition of NF-κB in primary astrocytes by expression of mutant IκBα suppressed expression of NOS2 and protected cocultured neurons from astrocyte-mediated apoptosis. These data indicate that inflammatory activation of astrocytes and enhanced nitrosative stress occurs at low doses of MPTP prior to loss of dopaminergic neurons. NF-κB-mediated expression of NOS2 appears to be a sensitive indicator of neuroinflammation that correlates with MPTP-induced neurochemical and neurobehavioral deficits prior to loss of dopaminergic neurons in the subtantia nigra.
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Affiliation(s)
- James A. Miller
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado
- Program in Molecular, Cellular, and Integrative Neuroscience, Colorado State University, Fort Collins, Colorado
| | - Briana R. Trout
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado
- Program in Molecular, Cellular, and Integrative Neuroscience, Colorado State University, Fort Collins, Colorado
| | - Kelly A. Sullivan
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado
| | | | - Ruth A. Roberts
- AstraZeneca Safety Assessment, Alderley Park, United Kingdom
| | - Ronald B. Tjalkens
- Center for Environmental Medicine, Colorado State University, Fort Collins, Colorado
- Program in Molecular, Cellular, and Integrative Neuroscience, Colorado State University, Fort Collins, Colorado
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7139
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Hattiangady B, Kuruba R, Shetty AK. Acute Seizures in Old Age Leads to a Greater Loss of CA1 Pyramidal Neurons, an Increased Propensity for Developing Chronic TLE and a Severe Cognitive Dysfunction. Aging Dis 2011; 2:1-17. [PMID: 21339903 PMCID: PMC3041587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 01/26/2010] [Accepted: 01/26/2010] [Indexed: 05/30/2023] Open
Abstract
The aged population displays an enhanced risk for developing acute seizure (AS) activity. However, it is unclear whether AS activity in old age would result in a greater magnitude of hippocampal neurodegeneration and inflammation, and an increased predilection for developing chronic temporal lobe epilepsy (TLE) and cognitive dysfunction. Therefore, we addressed these issues in young-adult (5-months old) and aged (22-months old) F344 rats after three-hours of AS activity, induced through graded intraperitoneal injections of kainic acid (KA), and terminated through a diazepam injection. During the three-hours of AS activity, both young adult and aged groups exhibited similar numbers of stage-V motor seizures but the numbers of stage-IV motor seizures were greater in the aged group. In both age groups, three-hour AS activity induced degeneration of 50-55% of neurons in the dentate hilus, 22-32% of neurons in the granule cell layer and 49-52% neurons in the CA3 pyramidal cell layer without showing any interaction between the age and AS activity. However, degeneration of neurons in the CA1 pyramidal cell layer showed a clear interaction between the age and AS activity (12% in the young adult group and 56% in the aged group), suggesting that an advanced age makes the CA1 pyramidal neurons more susceptible to die with AS activity. The extent of inflammation measured through the numbers of activated microglial cells was similar between the two age groups. Interestingly, the predisposition for developing chronic TLE at 2-3 months after AS activity was 60% for young adult rats but 100% for aged rats. Moreover, both frequency & intensity of spontaneous recurrent seizures in the chronic phase after AS activity were 6-12 folds greater in aged rats than in young adult rats. Furthermore, aged rats lost their ability for spatial learning even in a scrupulous eleven-session water maze learning paradigm after AS activity, in divergence from young adult rats which retained the ability for spatial learning but had memory retrieval dysfunction after AS activity. Thus, AS activity in old age results in a greater loss of hippocampal CA1 pyramidal neurons, an increased propensity for developing robust chronic TLE, and a severe cognitive dysfunction.
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Affiliation(s)
| | | | - Ashok K. Shetty
- Correspondence should be addressed to: Ashok K. Shetty, M.Sc., Ph.D., Division of Neurosurgery, DUMC Box 3807, Duke University Medical Center, Durham NC 27710. E-mail:
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7140
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Lahaie-Collins V, Bournival J, Plouffe M, Carange J, Martinoli MG. Sesamin modulates tyrosine hydroxylase, superoxide dismutase, catalase, inducible NO synthase and interleukin-6 expression in dopaminergic cells under MPP+-induced oxidative stress. Oxid Med Cell Longev 2011; 1:54-62. [PMID: 19794909 PMCID: PMC2715194 DOI: 10.4161/oxim.1.1.6958] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 08/28/2008] [Accepted: 09/08/2008] [Indexed: 11/19/2022]
Abstract
Oxidative stress is regarded as a mediator of nerve cell death in several neurodegenerative disorders, such as Parkinson's disease. Sesamin, a lignan mainly found in sesame oil, is currently under study for its anti-oxidative and possible neuroprotective properties. We used 1-methyl-4-phenyl-pyridine (MPP(+)) ion, the active metabolite of the potent parkinsonism-causing toxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine, to produce oxidative stress and neurodegeneration in neuronal PC12 cells, which express dopamine, as well as neurofilaments. Our results show that picomolar doses of sesamin protected neuronal PC12 cells from MPP(+)-induced cellular death, as revealed by colorimetric measurements and production of reactive oxygen species. We also demonstrated that sesamin acted by rescuing tyrosine hydroxylase levels from MPP(+)-induced depletion. Sesamin, however, did not modulate dopamine transporter levels, and estrogen receptor-alpha and -beta protein expression. By examining several parameters of cell distress, we found that sesamin also elicited a strong increase in superoxide dismutase activity as well as protein expression and decreased catalase activity and the MPP(+) stimulated inducible nitric oxide synthase protein expression, in neuronal PC12 cells. Finally, sesamin possessed significant anti-inflammatory properties, as disclosed by its potential to reduce MPP(+)-induced interleukin-6 mRNA levels in microglia. From these studies, we determined the importance of the lignan sesamin as a neuroprotective molecule and its possible role in complementary and/or preventive therapies of neurodegenerative diseases.
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Affiliation(s)
- Vicky Lahaie-Collins
- Department of Biochemistry, Neuroscience Research Group, Université du Québec, Trois-Rivières, Québec, Canada
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7141
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Stienen MN, Haghikia A, Dambach H, Thöne J, Wiemann M, Gold R, Chan A, Dermietzel R, Faustmann PM, Hinkerohe D, Prochnow N. Anti-inflammatory effects of the anticonvulsant drug levetiracetam on electrophysiological properties of astroglia are mediated via TGFβ1 regulation. Br J Pharmacol 2011; 162:491-507. [PMID: 20955362 PMCID: PMC3031068 DOI: 10.1111/j.1476-5381.2010.01038.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 08/29/2010] [Accepted: 09/02/2010] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE The involvement of astrocytes as immune-competent players in inflammation and the pathogenesis of epilepsy and seizure-induced brain damage has recently been recognized. In clinical trials and practice, levetiracetam (LEV) has proven to be an effective antiepileptic drug (AED) in various forms of epileptic seizures, when applied as mono- or added therapy. Little is known about the mechanism(s) of action of LEV. Evidence so far suggests a mode of action different from that of classical AEDs. We have shown that LEV restored functional gap junction coupling and basic membrane properties in an astrocytic inflammatory model in vitro. EXPERIMENTAL APPROACH Here, we used neonatal rat astrocytes co-cultured with high proportions (30%) of activated microglia or treated with the pro-inflammatory cytokine interleukin-1β to provoke inflammatory responses. Effects of LEV (50 µg·mL⁻¹) on electrophysiological properties of astrocytes (by whole cell patch clamp) and on secretion of TGFβ1 (by (ELISA)) were studied in these co-cultures. KEY RESULTS LEV restored impaired astrocyte membrane resting potentials via modification of inward and outward rectifier currents, and promoted TGFβ1 expression in inflammatory and control co-cultures. Furthermore, LEV and TGFβ1 exhibited similar facilitating effects on the generation of astrocyte voltage-gated currents in inflammatory co-cultures and the effects of LEV were prevented by antibody to TGFβ1. CONCLUSIONS AND IMPLICATIONS Our data suggest that LEV is likely to reduce the harmful spread of excitation elicited by seizure events within the astro-glial functional syncytium, with stabilizing consequences for neuronal-glial interactions.
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7142
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Zhang W, Phillips K, Wielgus AR, Liu J, Albertini A, Zucca FA, Faust R, Qian SY, Miller DS, Chignell CF, Wilson B, Jackson-Lewis V, Przedborski S, Joset D, Loike J, Hong JS, Sulzer D, Zecca L. Neuromelanin activates microglia and induces degeneration of dopaminergic neurons: implications for progression of Parkinson's disease. Neurotox Res 2011; 19:63-72. [PMID: 19957214 PMCID: PMC3603276 DOI: 10.1007/s12640-009-9140-z] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/19/2009] [Accepted: 11/19/2009] [Indexed: 12/28/2022]
Abstract
In Parkinson's disease (PD), there is a progressive loss of neuromelanin (NM)-containing dopamine neurons in substantia nigra (SN) which is associated with microgliosis and presence of extracellular NM. Herein, we have investigated the interplay between microglia and human NM on the degeneration of SN dopaminergic neurons. Although NM particles are phagocytized and degraded by microglia within minutes in vitro, extracellular NM particles induce microglial activation and ensuing production of superoxide, nitric oxide, hydrogen peroxide (H₂O₂), and pro-inflammatory factors. Furthermore, NM produces, in a microglia-depended manner, neurodegeneration in primary ventral midbrain cultures. Neurodegeneration was effectively attenuated with microglia derived from mice deficient in macrophage antigen complex-1, a microglial integrin receptor involved in the initiation of phagocytosis. Neuronal loss was also attenuated with microglia derived from mice deficient in phagocytic oxidase, a subunit of NADPH oxidase, that is responsible for superoxide and H₂O₂ production, or apocynin, an NADPH oxidase inhibitor. In vivo, NM injected into rat SN produces microgliosis and a loss of tyrosine hydroxylase neurons. Thus, these results show that extracellular NM can activate microglia, which in turn may induce dopaminergic neurodegeneration in PD. Our study may have far-reaching implications, both pathogenic and therapeutic.
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Affiliation(s)
- Wei Zhang
- Department of Neurology, Beijing Tiantan Hospital, Beijing 100050, China
| | - Kester Phillips
- Department of Psychiatry, Neurology and Pharmacology, Columbia University, New York, NY 10032, USA
| | - Albert R. Wielgus
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Jie Liu
- Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Alberto Albertini
- Institute of Biomedical Technologies-Italian National Research Council, 20090 Segrate (Milano), Italy
| | - Fabio A. Zucca
- Institute of Biomedical Technologies-Italian National Research Council, 20090 Segrate (Milano), Italy
| | - Rudolph Faust
- Department of Psychiatry, Neurology and Pharmacology, Columbia University, New York, NY 10032, USA
| | - Steven Y. Qian
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - David S. Miller
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Colin F. Chignell
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Belinda Wilson
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | - Serge Przedborski
- Department of Neurology, Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Danielle Joset
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - John Loike
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Jau-Shyong Hong
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - David Sulzer
- Department of Psychiatry, Neurology and Pharmacology, Columbia University, New York, NY 10032, USA
| | - Luigi Zecca
- Institute of Biomedical Technologies-Italian National Research Council, 20090 Segrate (Milano), Italy
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7143
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Wager-Smith K, Markou A. Depression: a repair response to stress-induced neuronal microdamage that can grade into a chronic neuroinflammatory condition? Neurosci Biobehav Rev 2011; 35:742-64. [PMID: 20883718 PMCID: PMC3777427 DOI: 10.1016/j.neubiorev.2010.09.010] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 09/17/2010] [Accepted: 09/21/2010] [Indexed: 12/19/2022]
Abstract
Depression is a major contributor to the global burden of disease and disability, yet it is poorly understood. Here we review data supporting a novel theoretical model for the biology of depression. In this model, a stressful life event leads to microdamage in the brain. This damage triggers an injury repair response consisting of a neuroinflammatory phase to clear cellular debris and a spontaneous tissue regeneration phase involving neurotrophins and neurogenesis. During healing, released inflammatory mediators trigger sickness behavior and psychological pain via mechanisms similar to those that produce physical pain during wound healing. The depression remits if the neuronal injury repair process resolves successfully. Importantly, however, the acute psychological pain and neuroinflammation often transition to chronicity and develop into pathological depressive states. This hypothesis for depression explains substantially more data than alternative models, including why emerging data show that analgesic, anti-inflammatory, pro-neurogenic and pro-neurotrophic treatments have antidepressant effects. Thus, an acute depressive episode can be conceptualized as a normally self-limiting but highly error-prone process of recuperation from stress-triggered neuronal microdamage.
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Affiliation(s)
- Karen Wager-Smith
- Department of Psychiatry, School of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA.
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7144
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Gemma C. Neuroimmunomodulation and Aging. Aging Dis 2010; 1:169-172. [PMID: 21297896 PMCID: PMC3033048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
Inflammation is by definition a protective phase of the immune response. The very first goal of inflammation is destroying and phagocytosing infected or damaged cells to avoid the spread of the pathogen or of the damage to neighboring, healthy, cells. However, we now know that during many chronic neurological disorders, inflammation and degeneration always coexist at certain time points. For example, inflammation comes first in multiple sclerosis, but degeneration follows, while in Alzheimer's or Parkinson's disease degeneration starts and inflammation is secondary. Either way these are the two pathological detectable problems. The central nervous system (CNS) has long been viewed as exempt from the effects of the immune system. The brain has physical barriers for protection, and it is now clear that cells in the nervous system respond to inflammation and injury in unique ways. In recent years, researchers have presented evidence supporting the idea that in the CNS there is an ongoing protective inflammatory mechanism, which involves macrophage, monocytes, T cells, regulatory T-cells, effector T cells and many others; these, in turn, promote repair mechanisms in the brain not only during inflammatory, and degenerative disorders but also in healthy people. This "repair mechanism" can be considered as an intrinsic part of the physiological activities of the brain. It is now well known that the microenvironment of the brain is a crucial player in determining the relative contribution of the two different outcomes. Failure of molecular and cellular mechanisms sustaining the "brain-repair programme" might be, at least in part, a cause of neurological disorders. Today, the neurotoxic and neuroprotective roles of the innate immune reactions in aging, brain injury, ischemia, autoimmune and neurodegenerative disorders of the CNS are widely investigated and highly debated research topics. Nevertheless, several issues remain to be elucidated, notably the earlier cellular events that initiate dysregulation of brain inflammatory pathways. If these inflammatory processes could be identified and harnessed, then cognitive function may be protected during aging and age-related neurodegenerative diseases through early interventions directed against the negative consequences of inflammation. This commentary highlights the major issues/opinions presented by experts on the involvement of the brain immune system in aging and age-related diseases in a special edition of the journal Aging and Disease.
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Affiliation(s)
- Carmelina Gemma
- Correspondence should be addressed to: Dr. Carmelina Gemma, Department of Neurosurgery and Brain Repair MDC-78, USF HEALTH, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA.
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7145
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Üllen A, Fauler G, Köfeler H, Waltl S, Nusshold C, Bernhart E, Reicher H, Leis HJ, Wintersperger A, Malle E, Sattler W. Mouse brain plasmalogens are targets for hypochlorous acid-mediated modification in vitro and in vivo. Free Radic Biol Med 2010; 49:1655-65. [PMID: 20807565 PMCID: PMC4061399 DOI: 10.1016/j.freeradbiomed.2010.08.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 08/02/2010] [Accepted: 08/23/2010] [Indexed: 11/18/2022]
Abstract
Plasmalogens, 1-O-alk-1'-enyl-2-acyl-sn-glycerophospholipids, are significant constituents of cellular membranes and are essential for normal brain development. Plasmalogens, which contain a vinyl ether bond at the sn-1 position, are preferential targets for hypochlorous acid (HOCl), generated by myeloperoxidase (MPO) from H(2)O(2) and chloride ions. Because MPO is implicated in neurodegeneration, this study pursued two aims: (i) to investigate the reactivity of mouse brain plasmalogens toward HOCl in vitro and (ii) to obtain in vivo evidence for MPO-mediated brain plasmalogen modification. Liquid chromatography coupled to hybrid linear ion trap-Fourier transform-ion cyclotron resonance mass spectrometry revealed plasmalogen modification in mouse brain lipid extracts at lower HOCl concentrations as observed for diacylphospholipids, resulting in the generation of 2-chloro fatty aldehydes and lysophospholipids. Lysophosphatidylethanolamine accumulation was transient, whereas lysophosphatidylcholine species containing saturated acyl residues remained stable. In vivo, a single, systemic endotoxin injection resulted in upregulation of cerebral MPO mRNA levels to a range comparable to that observed for tumor necrosis factor-α and cyclooxygenase-2. This inflammatory response was accompanied by a significant decrease in several brain plasmalogen species and concomitant in vivo generation of 2-chlorohexadecanal. The present findings demonstrate that activation of the MPO-H(2)O(2)-chloride system under neuroinflammatory conditions results in oxidative attack of the total cerebral plasmalogen pool. As this lipid class is indispensable for normal neuronal function, HOCl-mediated plasmalogen modification is likely to compromise normal synaptic transmission.
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Affiliation(s)
- Andreas Üllen
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Günter Fauler
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, 8010 Graz, Austria
| | - Harald Köfeler
- Center of Medical Research, Medical University of Graz, 8010 Graz, Austria
| | - Sabine Waltl
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Christoph Nusshold
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Eva Bernhart
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Helga Reicher
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Hans-Jörg Leis
- Research Unit of Osteology and Analytical Mass Spectrometry, University Children’s Hospital, Medical University of Graz, 8010 Graz, Austria
| | - Andrea Wintersperger
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Ernst Malle
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
| | - Wolfgang Sattler
- Institute of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, 8010 Graz, Austria
- Corresponding author. Fax: +43 316 380 9615.
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7146
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Wu X, He Y, Hsuchou H, Kastin AJ, Rood JC, Pan W. Essential role of interleukin-15 receptor in normal anxiety behavior. Brain Behav Immun 2010; 24:1340-6. [PMID: 20600810 PMCID: PMC2949491 DOI: 10.1016/j.bbi.2010.06.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/15/2010] [Accepted: 06/22/2010] [Indexed: 10/19/2022] Open
Abstract
The interactions between the cytokine interleukin (IL)-15 and the classical neurotransmitter GABA have been shown in IL15Rα receptor knockout mice by observations of memory deficits and reduction of GABA. To test the hypothesis that IL15 affects anxiety-like behavior, knockout mice without IL15, IL15Rα, or the co-receptor IL2Rγ were subjected to open-field and elevated plus maze tests. All three strains showed reduction of anxiety, with greater changes in the IL15Rα knockout mice than in the IL15 or IL2Rγ knockout mice. This unexpected observation is opposite to the reported increase of anxiety in mice lacking other proinflammatory cytokines or their receptors. The reduced anxiety was not associated with changes in associated serum cytokines. However, Western blotting, qPCR, and immunohistochemistry all showed that IL15Rα knockout mice had mild microgliosis and astrogliosis in the hippocampus. To determine whether this gliosis plays a role in decreasing anxiety, IL15Rα knockout mice were treated with minocycline, but this did not cause a change in open field performance. To determine whether IL15 plays a direct role in anxiety, wildtype mice were treated with IL15 by intraperitoneal injection. This also failed to cause a change in open field behavior under the experimental conditions tested. Thus, IL15Rα is essential for normal anxiety-like behavior, but inhibition of gliosis in the fearless IL15Rα knockout mice or IL15 treatment of normal mice did not acutely modulate behavioral performance as tested.
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7147
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Gelbard HA, Dewhurst S, Maggirwar SB, Kiebala M, Polesskaya O, Gendelman HE. Rebuilding synaptic architecture in HIV-1 associated neurocognitive disease: a therapeutic strategy based on modulation of mixed lineage kinase. Neurotherapeutics 2010; 7:392-8. [PMID: 20880503 PMCID: PMC2948545 DOI: 10.1016/j.nurt.2010.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 07/28/2010] [Accepted: 08/04/2010] [Indexed: 12/13/2022] Open
Abstract
Work from our laboratories has validated mixed lineage kinase type 3 (MLK3) as an enzyme pathologically activated in the CNS by human immunodeficiency virus 1 (HIV-1) neurotoxins. In this review, we discuss MLK3 activation in the context of the neuropathogenesis of HIV-1 associated neurocognitive deficits (HAND). We use findings from the literature to substantiate the neuropathologic relevance of MLK3 to neurodegenerative disease, with an emphasis on Parkinson's disease that shares a number of important phenotypic and neuropathologic characteristics with HAND. We discuss signal transduction pathways downstream from MLK3 activation, with an emphasis on their involvement in microglia and neurons in preclinical models of HAND. Finally, we make a case for pharmacologic intervention targeted at inhibition of MLK3 as a strategy to reverse HAND, in light of the fact that combination antiretroviral therapy, despite successfully managing systemic infection of HIV-1, has been largely unsuccessful in eradicating HAND.
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Affiliation(s)
- Harris A Gelbard
- Center for Neural Development and Disease, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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7148
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Langdon KD, Maclellan CL, Corbett D. Prolonged, 24-h delayed peripheral inflammation increases short- and long-term functional impairment and histopathological damage after focal ischemia in the rat. J Cereb Blood Flow Metab 2010; 30:1450-9. [PMID: 20332799 DOI: 10.1038/jcbfm.2010.23] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The incidence of infection among stroke patients is alarmingly high and both acute and delayed infections increase morbidity and mortality. Experimental studies support the acute clinical data, but little attention has focused on delayed systemic infections. Here, we investigated the effects of prolonged systemic inflammation either before or 24-h after ischemia. Systemic inflammation was induced by injecting rats with three separate doses of lipopolysaccharide (LPS; 50 mug/kg, i.p.) with core temperature monitoring for 48-h after middle cerebral artery occlusion (MCAo). Lipopolysaccharide injected before MCAo increased injury by approximately 30%, whereas delayed injection increased injury by approximately 85% (30-day survival). Proinflammatory cytokines assessed repeatedly for 72 h were significantly and persistently elevated with inflammation. This was accompanied by increases in microglia/macrophage and infiltrating leukocyte numbers in delayed LPS-treated animals. Behavioral assessments at 7 and 30 days revealed approximately 15% deficit in hindlimb function in animals treated with LPS 24-h after ischemia. Clearly, delayed and prolonged postischemic systemic inflammation has devastating effects on stroke outcome, in the absence of a prolonged febrile response. These findings, together with corroborative clinical data, emphasize the importance of early intervention to counteract the deleterious consequences of stroke-associated inflammation and infection.
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7149
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Horti AG, Gao Y, Ravert HT, Finley P, Valentine H, Wong DF, Endres CJ, Savonenko AV, Dannals RF. Synthesis and biodistribution of [11C]A-836339, a new potential radioligand for PET imaging of cannabinoid type 2 receptors (CB2). Bioorg Med Chem 2010; 18:5202-7. [PMID: 20554448 PMCID: PMC2903661 DOI: 10.1016/j.bmc.2010.05.058] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 05/17/2010] [Accepted: 05/20/2010] [Indexed: 12/22/2022]
Abstract
Recently, A-836339 [2,2,3,3-tetramethylcyclopropanecarboxylic acid [3-(2-methoxyethyl)-4,5-dimethyl-3H-thiazol-(2Z)-ylidene]amide] (1) was reported to be a selective CB2 agonist with high binding affinity. Here we describe the radiosynthesis of [11C]A-836339 ([11C]1) via its desmethyl precursor as a candidate radioligand for imaging CB2 receptors with positron-emission tomography (PET). Whole body and the regional brain distribution of [11C]1 in control CD1 mice demonstrated that this radioligand exhibits specific uptake in the CB2-rich spleen and little specific in vivo binding in the control mouse brain. However, [11C]1 shows specific cerebral uptake in the lipopolysaccharide (LPS)-induced mouse model of neuroinflammation and in the brain areas with Abeta amyloid plaque deposition in a mouse model of Alzheimer's disease (APPswe/PS1dE9 mice). These data establish a proof of principle that CB2 receptors binding in the neuroinflammation and related disorders can be measured in vivo.
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Affiliation(s)
- Andrew G Horti
- Division of Nuclear Medicine, Department of Radiology, Johns Hopkins Medical Institutions, 600 North Wolfe Street, Baltimore, MD 21287-0816, USA.
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7150
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Melchior B, Garcia AE, Hsiung BK, Lo KM, Doose JM, Thrash JC, Stalder AK, Staufenbiel M, Neumann H, Carson MJ. Dual induction of TREM2 and tolerance-related transcript, Tmem176b, in amyloid transgenic mice: implications for vaccine-based therapies for Alzheimer's disease. ASN Neuro 2010; 2:e00037. [PMID: 20640189 DOI: 10.1042/AN20100010] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/07/2010] [Accepted: 06/14/2010] [Indexed: 12/12/2022] Open
Abstract
Vaccine-based autoimmune (anti-amyloid) treatments are currently being examined for their therapeutic potential in Alzheimer's disease. In the present study we examined, in a transgenic model of amyloid pathology, the expression of two molecules previously implicated in decreasing the severity of autoimmune responses: TREM2 (triggering receptor expressed on myeloid cells 2) and the intracellular tolerance-associated transcript, Tmem176b (transmembrane domain protein 176b). In situ hybridization analysis revealed that both molecules were highly expressed in plaque-associated microglia, but their expression defined two different zones of plaque-associated activation. Tmem176b expression was highest in the inner zone of amyloid plaques, whereas TREM2 expression was highest in the outer zone. Induced expression of TREM2 occurred co-incident with detection of thioflavine-S-positive amyloid deposits. Transfection studies revealed that expression of TREM2 correlated negatively with motility, but correlated positively with the ability of microglia to stimulate CD4+ T-cell proliferation, TNF (tumour necrosis factor) and CCL2 (chemokine ligand 2) production, but not IFNγ (interferon γ) production. TREM2 expression also showed a positive correlation with amyloid phagocytosis in unactivated cells. However, activating cells with LPS (lipopolysaccharide), but not IFNγ, reduced the correlation between TREM2 expression and phagocytosis. Transfection of Tmem176b into both microglial and macrophage cell lines increased apoptosis. Taken together, these data suggest that, in vivo, Tmem176b+ cells in closest apposition to amyloid may be the least able to clear amyloid. Conversely, the phagocytic TREM2+ microglia on the plaque outer zones are positioned to capture and present self-antigens to CNS (central nervous system)-infiltrating lymphocytes without promoting pro-inflammatory lymphocyte responses. Instead, plaque-associated TREM2+ microglia have the potential to evoke neuroprotective immune responses that may serve to support CNS function during pro-inflammatory anti-amyloid immune therapies.
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Key Words
- Aβ, amyloid β peptide
- CCL2, chemokine ligand 2
- CFSE, carboxyfluorescein succinimidyl ester
- CNS, central nervous system
- Clast1
- DAMP, danger-associated molecular pattern
- DMEM, Dulbecco's modified Eagle's medium
- EAE, experimentally induced autoimmune encephalomyelitis
- FBS, fetal bovine serum
- GFP, green fluorescent protein
- HPRT, hypoxanthine phosphoribosyl transferase
- IFNγ, interferon γ
- IL, interleukin
- KO, knockout
- LPS, lipopolysaccharide
- PFA, paraformaldehyde
- TNF, tumour necrosis factor
- TREM2, triggering receptor expressed on myeloid cells 2
- Thio-S, thioflavine-S
- Tmem176b, transmembrane domain protein 176b
- Torid
- WT, wild-type
- antigen presentation
- autoimmunity
- neuroinflammation
- qPCR, quantitative PCR
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