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Sen ZD, Danyeli LV, Woelfer M, Lamers F, Wagner G, Sobanski T, Walter M. Linking atypical depression and insulin resistance-related disorders via low-grade chronic inflammation: Integrating the phenotypic, molecular and neuroanatomical dimensions. Brain Behav Immun 2021; 93:335-352. [PMID: 33359233 DOI: 10.1016/j.bbi.2020.12.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022] Open
Abstract
Insulin resistance (IR) and related disorders, such as T2DM, increase the risk of major depressive disorder (MDD) and vice versa. Current evidence indicates that psychological stress and overeating can induce chronic low-grade inflammation that can interfere with glutamate metabolism in MDD as well as insulin signaling, particularly in the atypical subtype. Here we first review the interactive role of inflammatory processes in the development of MDD, IR and related metabolic disorders. Next, we describe the role of the anterior cingulate cortex in the pathophysiology of MDD and IR-related disorders. Furthermore, we outline how specific clinical features of atypical depression, such as hyperphagia, are more associated with inflammation and IR-related disorders. Finally, we examine the regional specificity of the effects of inflammation on the brain that show an overlap with the functional and morphometric brain patterns activated in MDD and IR-related disorders.
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Affiliation(s)
- Zümrüt Duygu Sen
- Department of Psychiatry and Psychotherapy, University Tuebingen, Calwerstraße 14, 72076 Tuebingen, Germany; Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany
| | - Lena Vera Danyeli
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Marie Woelfer
- Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Femke Lamers
- Department of Psychiatry, Amsterdam UMC, Vrije Universiteit, Oldenaller 1, 1081 HJ Amsterdam, the Netherlands
| | - Gerd Wagner
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany
| | - Thomas Sobanski
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Thueringen-Kliniken "Georgius Agricola" GmbH, Rainweg 68, 07318 Saalfeld, Germany
| | - Martin Walter
- Department of Psychiatry and Psychotherapy, University Tuebingen, Calwerstraße 14, 72076 Tuebingen, Germany; Department of Psychiatry and Psychotherapy, Jena University Hospital, Philosophenweg 3, 07743 Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Leipziger Str. 44, Building 65, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany.
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2
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Oschwald A, Petry P, Kierdorf K, Erny D. CNS Macrophages and Infant Infections. Front Immunol 2020; 11:2123. [PMID: 33072074 PMCID: PMC7531029 DOI: 10.3389/fimmu.2020.02123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/05/2020] [Indexed: 12/11/2022] Open
Abstract
The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.
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Affiliation(s)
- Alexander Oschwald
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Philippe Petry
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany.,CIBBS Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Daniel Erny
- Faculty of Medicine, Institute of Neuropathology, University of Freiburg, Freiburg, Germany
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3
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Hensel N, Raker V, Förthmann B, Buch A, Sodeik B, Pich A, Claus P. The Proteome and Secretome of Cortical Brain Cells Infected With Herpes Simplex Virus. Front Neurol 2020; 11:844. [PMID: 32973653 PMCID: PMC7481480 DOI: 10.3389/fneur.2020.00844] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/07/2020] [Indexed: 01/22/2023] Open
Abstract
Infections of the brain with herpes simplex virus type 1 (HSV-1) cause life-threatening Herpes simplex encephalitis (HSE) characterized by viral replication in neurons and neuro-inflammation including an infiltration of peripheral immune cells. HSV-1 reprograms host cells to foster its own replication and for immune evasion, but eventually the immune responses clear the infection in most patients. However, many survivors suffer from long-term neuronal damage and cannot regenerate all brain functions. HSV-1 influences the physiology of neurons, astrocytes, oligodendrocytes and microglia, and significantly changes their protein expression and secretion pattern. To characterize temporal changes upon HSV-1 infection in detail, we inoculated mixed primary cultures of the murine brain cortex, and performed quantitative mass spectrometry analyses of the cell-associated proteome and the secretome. We identified 28 differentially regulated host proteins influencing inflammasome formation and intracellular vesicle trafficking during endocytosis and secretion. The NIMA-related kinase 7 (NEK7), a critical component of the inflammasome, and ArfGap1, a regulator of endocytosis, were significantly up-regulated upon HSV-1 infection. In the secretome, we identified 71 proteins including guidance cues regulating axonal regeneration, such as semaphorin6D, which were enriched in the conditioned media of HSV-1 infected cells. Modulation of inflammasome activity and intracellular membrane traffic are critical for HSV-1 cell entry, virus assembly, and intracellular spread. Our proteome analysis provides first clues on host factors that might dampen the inflammasome response and modulate intracellular vesicle transport to promote HSV infection of the brain. Furthermore, our secretome analysis revealed a set of proteins involved in neuroregeneration that might foster neuronal repair processes to restore brain functions after clearance of an HSV-1 infection.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hanover, Germany.,Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Center for Systems Neuroscience (ZSN), Hanover, Germany
| | - Verena Raker
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hanover, Germany.,Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Center for Systems Neuroscience (ZSN), Hanover, Germany
| | - Benjamin Förthmann
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hanover, Germany.,Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Center for Systems Neuroscience (ZSN), Hanover, Germany
| | - Anna Buch
- Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Institute of Virology, Hannover Medical School, Hanover, Germany
| | - Beate Sodeik
- Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Center for Systems Neuroscience (ZSN), Hanover, Germany.,Institute of Virology, Hannover Medical School, Hanover, Germany.,DZIF-German Centre for Infection Research, Partner Site Hannover-Braunschweig, Hanover, Germany
| | - Andreas Pich
- Institute for Toxicology, Hannover Medical School, Hanover, Germany.,Core Facility Proteomics, Hannover Medical School, Hanover, Germany
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hanover, Germany.,Niedersachsen-Research Network on Neuroinfectiology (N-RENNT), Hanover, Germany.,Center for Systems Neuroscience (ZSN), Hanover, Germany
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4
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Wang Y, Jia J, Wang Y, Li F, Song X, Qin S, Wang Z, Kitazato K, Wang Y. Roles of HSV-1 infection-induced microglial immune responses in CNS diseases: friends or foes? Crit Rev Microbiol 2019; 45:581-594. [PMID: 31512533 DOI: 10.1080/1040841x.2019.1660615] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Microglia, as brain-resident macrophages, are the first line of defense against brain invading pathogens. Further, their dysfunction has been recognized to be closely associated with mounting CNS diseases. Of note, chronic HSV-1 infection leads to the persistent activation of microglia, which elicit a comprehensive response by generating certain factors with neurotoxic and neuroprotective effects. CNS infection with HSV-1 results in herpes simplex encephalitis and herpes simplex keratitis. Microglial immune response plays a crucial role in the development of these diseases. Moreover, HSV-1 infection is strongly associated with several CNS diseases, especially Alzheimer's disease and schizophrenia. These CNS diseases can be effectively ameliorated by eliciting an appropriate immune response, such as inhibition of microglial proliferation and activation. Therefore, it is crucial to reassess the positive and negative roles of microglia in HSV-1 CNS infection for a more comprehensive and detailed understanding of the relationship between microglia and CNS diseases. Hence, the present review focuses on the dual roles of microglia in mediating HSV-1 CNS infection, as well as on the strategy of targeting microglia to ameliorate CNS diseases. Further research in this field can help comprehensively elucidate the dual role of the microglial immune response in HSV-1 CNS infection, providing a theoretical basis for identifying therapeutic targets against overactive microglia in CNS diseases and HSV-1 infection.
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Affiliation(s)
- Yiliang Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China
| | - Jiaoyan Jia
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China
| | - Yun Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Feng Li
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China
| | - Xiaowei Song
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China.,College of Pharmacy, Jinan University, Guangzhou, China
| | - Shurong Qin
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China.,College of Pharmacy, Jinan University, Guangzhou, China
| | - Zhaoyang Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China.,Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan University, Guangzhou, China
| | - Kaio Kitazato
- Division of Molecular Pharmacology of Infectious Agents, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yifei Wang
- Guangzhou Jinan Biomedicine Research and Development Center, Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China.,Key Laboratory of Virology of Guangzhou, Jinan University, Guangzhou, China
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5
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Burmeister AR, Johnson MB, Yaemmongkol JJ, Marriott I. Murine astrocytes produce IL-24 and are susceptible to the immunosuppressive effects of this cytokine. J Neuroinflammation 2019; 16:55. [PMID: 30825881 PMCID: PMC6397747 DOI: 10.1186/s12974-019-1444-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/24/2019] [Indexed: 01/03/2023] Open
Abstract
Background Glia are key regulators of inflammatory responses within the central nervous system (CNS) following infection or trauma. We have previously demonstrated the ability of activated glia to rapidly produce pro-inflammatory mediators followed by a transition to an anti-inflammatory cytokine production profile that includes the immunosuppressive cytokine interleukin (IL)-10 and the closely related cytokine IL-19. IL-24, another member of the IL-10 family, has been studied in a number of inflammatory conditions in the periphery and is known to modulate immune cell activity. However, the ability of glia to produce IL-24 remains unclear and the effects of this pleiotropic cytokine on glial immune functions have not been investigated. Methods In this study, we have assessed whether primary murine glia produce IL-24 following stimulation and evaluated the effect of this cytokine on the immune responses of such cells. We have utilized RT-PCR and immunoblot analyses to assess the expression of IL-24 and its cognate receptors by astrocytes following challenge with bacteria or their components. Furthermore, we have determined the effect of recombinant IL-24 on astrocyte immune signaling and responses to clinically relevant bacteria using RT-PCR and specific capture ELISAs. Results We demonstrate that astrocytes express IL-24 mRNA and release detectable amounts of this cytokine protein in a delayed manner following bacterial challenge. In addition, we have determined that glia constitutively express the cognate receptors for IL-24 and show that such expression can be increased in astrocytes following activation. Importantly, our results indicate that IL-24 exerts an immunosuppressive effect on astrocytes by elevating suppressor of cytokine signaling 3 expression and limiting IL-6 production following challenge. Furthermore, we have demonstrated that IL-24 can also augment the release of IL-10 by bacterially challenged astrocytes and can induce the expression of the potentially neuroprotective mediators, glutamate transporter 1, and cyclooxygenase 2. Conclusions The expression of IL-24 and its cognate receptors by astrocytes following bacterial challenge, and the ability of this cytokine to limit inflammatory responses while promoting the expression of immunosuppressive and/or neuroprotective mediators, raises the intriguing possibility that IL-24 functions to regulate or resolve CNS inflammation following bacterial infection in order to limit neuronal damage.
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Affiliation(s)
- Amanda R Burmeister
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - M Brittany Johnson
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - Jessica J Yaemmongkol
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, NC, 28223, USA.
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6
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Burmeister AR, Marriott I. The Interleukin-10 Family of Cytokines and Their Role in the CNS. Front Cell Neurosci 2018; 12:458. [PMID: 30542269 PMCID: PMC6277801 DOI: 10.3389/fncel.2018.00458] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022] Open
Abstract
Resident cells of the central nervous system (CNS) play an important role in detecting insults and initiating protective or sometimes detrimental host immunity. At peripheral sites, immune responses follow a biphasic course with the rapid, but transient, production of inflammatory mediators giving way to the delayed release of factors that promote resolution and repair. Within the CNS, it is well known that glial cells contribute to the onset and progression of neuroinflammation, but it is only now becoming apparent that microglia and astrocytes also play an important role in producing and responding to immunosuppressive factors that serve to limit the detrimental effects of such responses. Interleukin-10 (IL-10) is generally considered to be the quintessential immunosuppressive cytokine, and its ability to resolve inflammation and promote wound repair at peripheral sites is well documented. In the present review article, we discuss the evidence for the production of IL-10 by glia, and describe the ability of CNS cells, including microglia and astrocytes, to respond to this suppressive factor. Furthermore, we review the literature for the expression of other members of the IL-10 cytokine family, IL-19, IL-20, IL-22 and IL-24, within the brain, and discuss the evidence of a role for these poorly understood cytokines in the regulation of infectious and sterile neuroinflammation. In concert, the available data indicate that glia can produce IL-10 and the related cytokines IL-19 and IL-24 in a delayed manner, and these cytokines can limit glial inflammatory responses and/or provide protection against CNS insult. However, the roles of other IL-10 family members within the CNS remain unclear, with IL-20 appearing to act as a pro-inflammatory factor, while IL-22 may play a protective role in some instances and a detrimental role in others, perhaps reflecting the pleiotropic nature of this cytokine family. What is clear is that our current understanding of the role of IL-10 and related cytokines within the CNS is limited at best, and further research is required to define the actions of this understudied family in inflammatory brain disorders.
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Affiliation(s)
- Amanda R Burmeister
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Ian Marriott
- Department of Biological Sciences, The University of North Carolina at Charlotte, Charlotte, NC, United States
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7
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Baxter VK, Glowinski R, Braxton AM, Potter MC, Slusher BS, Griffin DE. Glutamine antagonist-mediated immune suppression decreases pathology but delays virus clearance in mice during nonfatal alphavirus encephalomyelitis. Virology 2017; 508:134-149. [PMID: 28531865 PMCID: PMC5510753 DOI: 10.1016/j.virol.2017.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/14/2017] [Accepted: 05/17/2017] [Indexed: 01/21/2023]
Abstract
Infection of weanling C57BL/6 mice with the TE strain of Sindbis virus (SINV) causes nonfatal encephalomyelitis associated with hippocampal-based memory impairment that is partially prevented by treatment with 6-diazo-5-oxo-l-norleucine (DON), a glutamine antagonist (Potter et al., J Neurovirol 21:159, 2015). To determine the mechanism(s) of protection, lymph node and central nervous system (CNS) tissues from SINV-infected mice treated daily for 1 week with low (0.3mg/kg) or high (0.6mg/kg) dose DON were examined. DON treatment suppressed lymphocyte proliferation in cervical lymph nodes resulting in reduced CNS immune cell infiltration, inflammation, and cell death compared to untreated SINV-infected mice. Production of SINV-specific antibody and interferon-gamma were also impaired by DON treatment with a delay in virus clearance. Cessation of treatment allowed activation of the antiviral immune response and viral clearance, but revived CNS pathology, demonstrating the ability of the immune response to mediate both CNS damage and virus clearance.
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Affiliation(s)
- Victoria K Baxter
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Rebecca Glowinski
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Alicia M Braxton
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Michelle C Potter
- Johns Hopkins Drug Discovery and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Barbara S Slusher
- Johns Hopkins Drug Discovery and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Diane E Griffin
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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8
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Microglia derived from the axotomized adult rat facial nucleus uptake glutamate and metabolize it to glutamine in vitro. Neurochem Int 2016; 102:1-12. [PMID: 27816478 DOI: 10.1016/j.neuint.2016.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/12/2016] [Accepted: 10/31/2016] [Indexed: 11/22/2022]
Abstract
Microglia in the axotomized adult rat facial nucleus (axoFN) have been shown to highly express a glutamate transporter (GLT-1). The microglia appear to serve as glutamate (Glu) scavengers in the axoFN. However, there is no evidence that the microglia actually have the ability to uptake Glu and convert it to Gln. In this study, we investigated whether axoFN-derived microglia (axoFN-microglia) can uptake Glu and metabolize it to Gln. Microglia obtained by explant culture of axoFN on poly(N-isopropylacrylamide)-grafted dishes were non-invasively sub-cultured onto dishes or wells. Immunoblotting and Glu-uptake experiments revealed that the axoFN-microglia uptake 14C-Glu mainly by GLT-1 activity. Immunoblotting and immunocytochemical methods clarified that axoFN-microglia express the Gln synthetase (GS) protein in the same manner as newborn rat brain-derived primary microglia (NRB-microglia). Biochemical analysis demonstrated that the specific activity of GS of axoFN-microglia is similar to that of NRB-microglia, suggesting that these microglia play equivalent roles in the metabolic conversion of Glu to Gln. Nuclear magnetic resonance analysis clarified that NRB-microglia metabolize [13C]Glu to [13C]Gln depending on the incubation time, inferring the similar potential of axoFN-microglia. Taken together, these results demonstrate that axoFN-microglia express functional GLT-1 and GS proteins, and are strongly suggested to serve as Glu scavengers in vivo.
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9
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Bhandare AM, Kapoor K, Farnham MM, Pilowsky PM. Microglia PACAP and glutamate: Friends or foes in seizure-induced autonomic dysfunction and SUDEP? Respir Physiol Neurobiol 2016; 226:39-50. [DOI: 10.1016/j.resp.2016.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 12/18/2022]
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10
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Buckingham SC, Robel S. Glutamate and tumor-associated epilepsy: glial cell dysfunction in the peritumoral environment. Neurochem Int 2013; 63:696-701. [PMID: 23385090 DOI: 10.1016/j.neuint.2013.01.027] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 11/30/2012] [Accepted: 01/27/2013] [Indexed: 01/22/2023]
Abstract
Seizures are a serious and debilitating co-morbidity of primary brain tumors that affect most patients, yet their etiology is poorly understood. In many CNS pathologies, including epilepsy and brain injury, high levels of extracellular glutamate have been implicated in seizure generation. It has been shown that gliomas release neurotoxic levels of glutamate through their high expression of system xc-. More recently it was shown that the surrounding peritumoral cortex is spontaneously hyperexcitable. In this review, we discuss how gliomas induce changes in the surrounding environment that may further contribute to elevated extracellular glutamate and tumor-associated seizures. Peritumoral astrocytes become reactive and lose their ability to remove glutamate, while microglia, in response to signals from glioma cells, may release glutamate. In addition, gliomas increase blood brain barrier permeability, allowing seizure-inducing serum components, including glutamate, into the peritumoral region. These factors, working together or alone, may influence the frequency and severity of tumor-associated epilepsy.
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Affiliation(s)
- Susan C Buckingham
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, 1719 6th Avenue South, Birmingham, AL 35294, USA.
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11
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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12
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Persson M, Rönnbäck L. Microglial self-defence mediated through GLT-1 and glutathione. Amino Acids 2011; 42:207-19. [PMID: 21373770 DOI: 10.1007/s00726-011-0865-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 11/27/2022]
Abstract
Glutamate is stored in synaptic vesicles in presynaptic neurons. It is released into the synaptic cleft to provide signalling to postsynaptic neurons. Normally, the astroglial glutamate transporters GLT-1 and GLAST take up glutamate to mediate a high signal-to-noise ratio in the synaptic signalling, and also to prevent excitotoxic effects by glutamate. In astrocytes, glutamate is transformed into glutamine, which is safely transported back to neurons. However, in pathological conditions, such as an ischemia or virus infection, astroglial transporters are down-regulated which could lead to excitotoxicity. Lately, it was shown that even microglia can express glutamate transporters during pathological events. Microglia have two systems for glutamate transport: GLT-1 for transport into the cells and the x (c) (-) system for transport out of the cells. We here review results from our work and others, which demonstrate that microglia in culture express GLT-1, but not GLAST, and transport glutamate from the extracellular space. We also show that TNF-α can induce increased microglial GLT-1 expression, possibly associating the expression with inflammatory systems. Furthermore, glutamate taken up through GLT-1 may be used for direct incorporation into glutathione and to fuel the intracellular glutamate pool to allow cystine uptake through the x (c) (-) system. This can lead to a defence against oxidative stress and have an antiviral function.
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Affiliation(s)
- Mikael Persson
- Department of Clinical Neuroscience and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Per Dubbsgatan 14, 1tr, 41345, Gothenburg, Sweden
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13
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Gras G, Samah B, Hubert A, Léone C, Porcheray F, Rimaniol AC. EAAT expression by macrophages and microglia: still more questions than answers. Amino Acids 2011; 42:221-9. [PMID: 21373769 DOI: 10.1007/s00726-011-0866-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/17/2011] [Indexed: 01/07/2023]
Abstract
Glutamate is the main excitatory amino acid, but its presence in the extracellular milieu has deleterious consequences. It may induce excitotoxicity and also compete with cystine for the use of the cystine-glutamate exchanger, blocking glutathione neosynthesis and inducing an oxidative stress-induced cell death. Both mechanisms are critical in the brain where up to 20% of total body oxygen consumption occurs. In normal conditions, the astrocytes ensure that extracellular concentration of glutamate is kept in the micromolar range, thanks to their coexpression of high-affinity glutamate transporters (EAATs) and glutamine synthetase (GS). Their protective function is nevertheless sensitive to situations such as oxidative stress or inflammatory processes. On the other hand, macrophages and microglia do not express EAATs and GS in physiological conditions and are the principal effector cells of brain inflammation. Since the late 1990s, a number of studies have now shown that both microglia and macrophages display inducible EAAT and GS expression, but the precise significance of this still remains poorly understood. Brain macrophages and microglia are sister cells but yet display differences. Both are highly sensitive to their microenvironment and can perform a variety of functions that may oppose each other. However, in the very particular environment of the healthy brain, they are maintained in a repressed state. The aim of this review is to present the current state of knowledge on brain macrophages and microglial cells activation, in order to help clarify their role in the regulation of glutamate under pathological conditions as well as its outcome.
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Affiliation(s)
- Gabriel Gras
- Division of Immuno-Virology, Institute of Emerging Diseases and Innovative Therapies, UMR E1 CEA DSV/IMETI/SIV and University Paris South-Paris 11, 18, route du Panorama, 92265, Fontenay-aux Roses, France.
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Changes in brain function and morphology in patients with recurring herpes simplex virus infections and chronic pain. Pain 2009; 144:200-8. [DOI: 10.1016/j.pain.2009.04.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 04/06/2009] [Accepted: 04/16/2009] [Indexed: 11/20/2022]
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15
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Persson M, Pekna M, Hansson E, Rönnbäck L. The complement-derived anaphylatoxin C5a increases microglial GLT-1 expression and glutamate uptake in a TNF-α-independent manner. Eur J Neurosci 2009; 29:267-74. [DOI: 10.1111/j.1460-9568.2008.06575.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lactate Contributes to Ammonia-Mediated Astroglial Dysfunction During Hyperammonemia. Neurochem Res 2008; 34:556-65. [DOI: 10.1007/s11064-008-9819-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Accepted: 07/31/2008] [Indexed: 10/21/2022]
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Widespread Unilateral Pain Associated With Herpes Simplex Virus Infections. THE JOURNAL OF PAIN 2008; 9:658-65. [DOI: 10.1016/j.jpain.2008.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/01/2008] [Accepted: 02/02/2008] [Indexed: 11/21/2022]
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