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Marciante AB, Tadjalli A, Burrowes KA, Oberto JR, Luca EK, Seven YB, Nikodemova M, Watters JJ, Baker TL, Mitchell GS. Microglia regulate motor neuron plasticity via reciprocal fractalkine/adenosine signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592939. [PMID: 38765982 PMCID: PMC11100694 DOI: 10.1101/2024.05.07.592939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Microglia are innate CNS immune cells that play key roles in supporting key CNS functions including brain plasticity. We now report a previously unknown role for microglia in regulating neuroplasticity within spinal phrenic motor neurons, the neurons driving diaphragm contractions and breathing. We demonstrate that microglia regulate phrenic long-term facilitation (pLTF), a form of respiratory memory lasting hours after repetitive exposures to brief periods of low oxygen (acute intermittent hypoxia; AIH) via neuronal/microglial fractalkine signaling. AIH-induced pLTF is regulated by the balance between competing intracellular signaling cascades initiated by serotonin vs adenosine, respectively. Although brainstem raphe neurons release the relevant serotonin, the cellular source of adenosine is unknown. We tested a model in which hypoxia initiates fractalkine signaling between phrenic motor neurons and nearby microglia that triggers extracellular adenosine accumulation. With moderate AIH, phrenic motor neuron adenosine 2A receptor activation undermines serotonin-dominant pLTF; in contrast, severe AIH drives pLTF by a unique, adenosine-dominant mechanism. Phrenic motor neuron fractalkine knockdown, cervical spinal fractalkine receptor inhibition on nearby microglia, and microglial depletion enhance serotonin-dominant pLTF with moderate AIH but suppress adenosine-dominant pLTF with severe AIH. Thus, microglia play novel functions in the healthy spinal cord, regulating hypoxia-induced neuroplasticity within the motor neurons responsible for breathing.
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Affiliation(s)
- Alexandria B. Marciante
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Arash Tadjalli
- Current Address: Nova Southeastern University, College of Allopathic Medicine (NSU MD), Department of Medical Education, 3200 South University Drive, Fort Lauderdale, FL 33328-2018
| | - Kayla A. Burrowes
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jose R. Oberto
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Edward K. Luca
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Yasin B. Seven
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Maria Nikodemova
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
| | - Jyoti J. Watters
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Tracy L. Baker
- Current Address: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706
| | - Gordon S. Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida; Gainesville, FL, USA 32610
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Fractalkine/CX3CR1-Dependent Modulation of Synaptic and Network Plasticity in Health and Disease. Neural Plast 2023; 2023:4637073. [PMID: 36644710 PMCID: PMC9833910 DOI: 10.1155/2023/4637073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 01/06/2023] Open
Abstract
CX3CR1 is a G protein-coupled receptor that is expressed exclusively by microglia within the brain parenchyma. The only known physiological CX3CR1 ligand is the chemokine fractalkine (FKN), which is constitutively expressed in neuronal cell membranes and tonically released by them. Through its key role in microglia-neuron communication, the FKN/CX3CR1 axis regulates microglial state, neuronal survival, synaptic plasticity, and a variety of synaptic functions, as well as neuronal excitability via cytokine release modulation, chemotaxis, and phagocytosis. Thus, the absence of CX3CR1 or any failure in the FKN/CX3CR1 axis has been linked to alterations in different brain functions, including changes in synaptic and network plasticity in structures such as the hippocampus, cortex, brainstem, and spinal cord. Since synaptic plasticity is a basic phenomenon in neural circuit integration and adjustment, here, we will review its modulation by the FKN/CX3CR1 axis in diverse brain circuits and its impact on brain function and adaptation in health and disease.
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Zhao J, Li Q, Ouyang X, Wang F, Li Q, Xu Z, Ji D, Wu Q, Zhang J, Lu C, Ji S, Li S. The effect of CX3CL1/ CX3CR1 signal axis on microglia in central nervous system diseases. JOURNAL OF NEURORESTORATOLOGY 2023. [DOI: 10.1016/j.jnrt.2023.100042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Cellular, synaptic, and network effects of chemokines in the central nervous system and their implications to behavior. Pharmacol Rep 2021; 73:1595-1625. [PMID: 34498203 PMCID: PMC8599319 DOI: 10.1007/s43440-021-00323-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 02/07/2023]
Abstract
Accumulating evidence highlights chemokines as key mediators of the bidirectional crosstalk between neurons and glial cells aimed at preserving brain functioning. The multifaceted role of these immune proteins in the CNS is mirrored by the complexity of the mechanisms underlying its biological function, including biased signaling. Neurons, only in concert with glial cells, are essential players in the modulation of brain homeostatic functions. Yet, attempts to dissect these complex multilevel mechanisms underlying coordination are still lacking. Therefore, the purpose of this review is to summarize the current knowledge about mechanisms underlying chemokine regulation of neuron-glia crosstalk linking molecular, cellular, network, and behavioral levels. Following a brief description of molecular mechanisms by which chemokines interact with their receptors and then summarizing cellular patterns of chemokine expression in the CNS, we next delve into the sequence and mechanisms of chemokine-regulated neuron-glia communication in the context of neuroprotection. We then define the interactions with other neurotransmitters, neuromodulators, and gliotransmitters. Finally, we describe their fine-tuning on the network level and the behavioral relevance of their modulation. We believe that a better understanding of the sequence and nature of events that drive neuro-glial communication holds promise for the development of new treatment strategies that could, in a context- and time-dependent manner, modulate the action of specific chemokines to promote brain repair and reduce the neurological impairment.
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Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
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Microglia-neuron crosstalk: Signaling mechanism and control of synaptic transmission. Semin Cell Dev Biol 2019; 94:138-151. [PMID: 31112798 DOI: 10.1016/j.semcdb.2019.05.017] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/17/2019] [Accepted: 05/16/2019] [Indexed: 12/13/2022]
Abstract
The continuous crosstalk between microglia and neurons is required for microglia housekeeping functions and contributes to brain homeostasis. Through these exchanges, microglia take part in crucial brain functions, including development and plasticity. The alteration of neuron-microglia communication contributes to brain disease states with consequences, ranging from synaptic function to neuronal survival. This review focuses on the signaling pathways responsible for neuron-microglia crosstalk, highlighting their physiological roles and their alteration or specific involvement in disease. In particular, we discuss studies, establishing how these signaling allow microglial cells to control relevant physiological functions during brain development, including synaptic formation and circuit refinement. In addition, we highlight how microglia and neurons interact functionally to regulate highly dynamical synaptic functions. Microglia are able to release several signaling molecules involved in the regulation of synaptic activity and plasticity. On the other side, molecules of neuronal origin control microglial processes motility in an activity-dependent manner. Indeed, the continuous crosstalk between microglia and neurons is required for the sensing and housekeeping functions of microglia and contributes to the maintenance of brain homeostasis and, particularly, to the sculpting of neuronal connections during development. These interactions lay on the delicate edge between physiological processes and homeostasis alteration in pathology and are themselves altered during neuroinflammation. The full description of these processes could be fundamental for understanding brain functioning in health and disease.
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The Role of Chemokines in the Pathophysiology of Major Depressive Disorder. Int J Mol Sci 2019; 20:ijms20092283. [PMID: 31075818 PMCID: PMC6539240 DOI: 10.3390/ijms20092283] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022] Open
Abstract
Major depressive disorder (MDD) is a debilitating condition, whose high prevalence and multisymptomatic nature set its standing as a leading contributor to global disability. To better understand this psychiatric disease, various pathophysiological mechanisms have been proposed, including changes in monoaminergic neurotransmission, imbalance of excitatory and inhibitory signaling in the brain, hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, and abnormalities in normal neurogenesis. While previous findings led to a deeper understanding of the disease, the pathogenesis of MDD has not yet been elucidated. Accumulating evidence has confirmed the association between chronic inflammation and MDD, which is manifested by increased levels of the C-reactive protein, as well as pro-inflammatory cytokines, such as Interleukin 1 beta, Interleukin 6, and the Tumor necrosis factor alpha. Furthermore, recent findings have implicated a related family of cytokines with chemotactic properties, known collectively as chemokines, in many neuroimmune processes relevant to psychiatric disorders. Chemokines are small (8–12 kDa) chemotactic cytokines, which are known to play roles in direct chemotaxis induction, leukocyte and macrophage migration, and inflammatory response propagation. The inflammatory chemokines possess the ability to induce migration of immune cells to the infection site, whereas their homeostatic chemokine counterparts are responsible for recruiting cells for their repair and maintenance. To further support the role of chemokines as central elements to healthy bodily function, recent studies suggest that these proteins demonstrate novel, brain-specific mechanisms including the modulation of neuroendocrine functions, chemotaxis, cell adhesion, and neuroinflammation. Elevated levels of chemokines in patient-derived serum have been detected in individuals diagnosed with major depressive disorder, bipolar disorder, and schizophrenia. Furthermore, despite the considerable heterogeneity of experimental samples and methodologies, existing biomarker studies have clearly demonstrated the important role of chemokines in the pathophysiology of psychiatric disorders. The purpose of this review is to summarize the data from contemporary experimental and clinical studies, and to evaluate available evidence for the role of chemokines in the central nervous system (CNS) under physiological and pathophysiological conditions. In light of recent results, chemokines could be considered as possible peripheral markers of psychiatric disorders, and/or targets for treating depressive disorders.
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Innes S, Pariante CM, Borsini A. Microglial-driven changes in synaptic plasticity: A possible role in major depressive disorder. Psychoneuroendocrinology 2019; 102:236-247. [PMID: 30594100 DOI: 10.1016/j.psyneuen.2018.12.233] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 12/16/2022]
Abstract
Recent data gathered from both in vitro and in vivo models of Major Depressive Disorder (MDD) have indicated that microglia play an active role in modifying some of the most important sources for neuronal plasticity, specifically long-term potentiation (LTP) and long-term depression (LTD). In addition, microglia have been implicated in neuro-immune interaction dysregulations, which are considered a core constituent of MDD pathology. While prior studies have investigated the diverse effects activated microglia can have in the context of depression, including regulation of inflammatory cytokine production and structural changes, recent evidence has revealed a more direct relationship between microglial activation and changes in synaptic function and plasticity, including LTP and LTD. Here we review these findings from animal models, as well as discuss how current preclinical evidence might shed light on novel therapeutic targets for patients with depressive disorder.
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Affiliation(s)
- Stuart Innes
- Guy's King's and St Thomas' School of Life Science and Medicine, King's College London, UK
| | - Carmine M Pariante
- Stress, Psychiatry and Immunology Laboratory, Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK
| | - Alessandra Borsini
- Stress, Psychiatry and Immunology Laboratory, Department of Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK.
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Luo P, Chu SF, Zhang Z, Xia CY, Chen NH. Fractalkine/CX3CR1 is involved in the cross-talk between neuron and glia in neurological diseases. Brain Res Bull 2018; 146:12-21. [PMID: 30496784 DOI: 10.1016/j.brainresbull.2018.11.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 11/17/2018] [Accepted: 11/23/2018] [Indexed: 01/27/2023]
Abstract
Fractalkine (CX3C chemokine ligand 1, CX3CL1) is an essential chemokine, for regulating adhesion and chemotaxis through binding to CX3CR1, which plays a critical role in the crosstalk between glial cells and neurons by direct or indirect ways in the central nervous system (CNS). Fractalkine/CX3CR1 axis regulates microglial activation and function, neuronal survival and synaptic function by controlling the release of inflammatory cytokines and synaptic plasticity in the course of the neurological disease. The multiple functions of fractalkine/CX3CR1 make it exert neuroprotective or neurotoxic effects, which determines the pathogenesis. However, the role of fractalkine/CX3CR1 in the CNS remains controversial. Whether it can be used as a therapeutic target for neurological diseases needs to be further investigated. In this review, we summarize the studies highlighting fractalkine/CX3CR1-mediated effects and discuss the potential neurotoxic and neuroprotective actions of fractalkine/CX3CR1 in brain injury for providing useful insights into the potential applications of fractalkine/CX3CR1 in neurological diseases.
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Affiliation(s)
- Piao Luo
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Zhao Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China
| | - Nai-Hong Chen
- College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, People's Republic of China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, People's Republic of China.
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Basilico B, Pagani F, Grimaldi A, Cortese B, Di Angelantonio S, Weinhard L, Gross C, Limatola C, Maggi L, Ragozzino D. Microglia shape presynaptic properties at developing glutamatergic synapses. Glia 2018; 67:53-67. [DOI: 10.1002/glia.23508] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/13/2018] [Accepted: 06/22/2018] [Indexed: 12/30/2022]
Affiliation(s)
| | | | | | - Barbara Cortese
- CNR NANOTEC-Istituto di Nanotecnologia, Dept of Physics; Sapienza University; Rome Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- Istituto Italiano di Tecnologia; Rome Italy
| | | | | | - Cristina Limatola
- Pasteur Institute, Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- IRCCS NEUROMED; Via Atinese Pozzilli Italy
| | - Laura Maggi
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology; Sapienza University; Rome Italy
- IRCCS NEUROMED; Via Atinese Pozzilli Italy
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Werneburg S, Feinberg PA, Johnson KM, Schafer DP. A microglia-cytokine axis to modulate synaptic connectivity and function. Curr Opin Neurobiol 2017; 47:138-145. [PMID: 29096242 DOI: 10.1016/j.conb.2017.10.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/25/2017] [Accepted: 10/07/2017] [Indexed: 02/05/2023]
Abstract
Microglia have recently been recognized as key regulators of synapse development, function, and plasticity. Critical to progressing the field is the identification of molecular underpinnings necessary for microglia to carry out these important functions within neural circuits. Here, we focus a review specifically on roles for microglial cytokine signaling within developing and mature neural circuits. We review exciting new studies demonstrating essential roles for microglial cytokine signaling in axon outgrowth, synaptogenesis and synapse maturation during development, as well as synaptic transmission and plasticity in adulthood. Together, these studies identify microglia and cytokines as critical modulators of neural circuits within the healthy brain, with implications for a broad range of neurological disorders with disruptions in synaptic structure and function.
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Affiliation(s)
- Sebastian Werneburg
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester MA 01605, USA
| | - Philip A Feinberg
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester MA 01605, USA
| | - Kasey M Johnson
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester MA 01605, USA
| | - Dorothy P Schafer
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester MA 01605, USA.
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Peña-Ortega F. Pharmacological Tools to Activate Microglia and their Possible use to Study Neural Network Patho-physiology. Curr Neuropharmacol 2017; 15:595-619. [PMID: 27697040 PMCID: PMC5543677 DOI: 10.2174/1570159x14666160928151546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/05/2016] [Accepted: 09/26/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Microglia are the resident immunocompetent cells of the CNS and also constitute a unique cell type that contributes to neural network homeostasis and function. Understanding microglia cell-signaling not only will reveal their diverse functions but also will help to identify pharmacological and non-pharmacological tools to modulate the activity of these cells. METHODS We undertook a search of bibliographic databases for peer-reviewed research literature to identify microglial activators and their cell-specificity. We also looked for their effects on neural network function and dysfunction. RESULTS We identified several pharmacological targets to modulate microglial function, which are more or less specific (with the proper control experiments). We also identified pharmacological targets that would require the development of new potent and specific modulators. We identified a wealth of evidence about the participation of microglia in neural network function and their alterations in pathological conditions. CONCLUSION The identification of specific microglia-activating signals provides experimental tools to modulate the activity of this heterogeneous cell type in order to evaluate its impact on other components of the nervous system, and it also helps to identify therapeutic approaches to ease some pathological conditions related to microglial dysfunction.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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Xu MX, Yu R, Shao LF, Zhang YX, Ge CX, Liu XM, Wu WY, Li JM, Kong LD. Up-regulated fractalkine (FKN) and its receptor CX3CR1 are involved in fructose-induced neuroinflammation: Suppression by curcumin. Brain Behav Immun 2016; 58:69-81. [PMID: 26765996 DOI: 10.1016/j.bbi.2016.01.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/08/2015] [Accepted: 01/01/2016] [Indexed: 12/11/2022] Open
Abstract
Recent studies suggest that diet-induced fractalkine (FKN) stimulates neuroinflammation in animal models of obesity, yet how it occurs is unclear. This study investigated the role of FKN and it receptor, CX3CR1, in fructose-induced neuroinflammation, and examined curcumin's beneficial effect. Fructose feeding was found to induce hippocampal microglia activation with neuroinflammation through the activation of the Toll-like receptor 4 (TLR4)/nuclear transcription factor κB (NF-κB) signaling, resulting in the reduction of neurogenesis in the dentate gyrus (DG) of mice. Serum FKN levels, as well as hypothalamic FKN and CX3CR1 gene expression, were significantly increased in fructose-fed mice with hypothalamic microglia activation. Hippocampal gene expression of FKN and CX3CR1 was also up-regulated at 14d and normalized at 56d in mice fed with fructose, which were consistent with the change of GFAP. Furthermore, immunostaining showed that GFAP and FKN expression was increased in cornu amonis 1, but decreased in DG in fructose-fed mice. In vitro studies showed that GFAP and FKN expression was stimulated in astrocytes, and suppressed in mixed glial cells exposed to 48h-fructose, with the continual increase of pro-inflammatory cytokines. Thus, increased FKN and CX3CR1 may cause a cross-talk between activated glial cells and neurons, playing an important role in the development of neuroinflammation in fructose-fed mice. Curcumin protected against neuronal damage in hippocampal DG of fructose-fed mice by inhibiting microglia activation and suppressed FKN/CX3CR1 up-regulation in the neuronal network. These results suggest a new therapeutic approach to protect against neuronal damage associated with dietary obesity-associated neuroinflammation.
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Affiliation(s)
- Min-Xuan Xu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Rong Yu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Li-Fei Shao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Yan-Xiu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Chen-Xu Ge
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Xin-Meng Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Wen-Yuan Wu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China
| | - Jian-Mei Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, PR China.
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The chemokine CXCL16 modulates neurotransmitter release in hippocampal CA1 area. Sci Rep 2016; 6:34633. [PMID: 27721466 PMCID: PMC5056385 DOI: 10.1038/srep34633] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/16/2016] [Indexed: 12/04/2022] Open
Abstract
Chemokines have several physio-pathological roles in the brain. Among them, the modulation of synaptic contacts and neurotransmission recently emerged as crucial activities during brain development, in adulthood, upon neuroinflammation and neurodegenerative diseases. CXCL16 is a chemokine normally expressed in the brain, where it exerts neuroprotective activity against glutamate-induced damages through cross communication with astrocytes and the involvement of the adenosine receptor type 3 (A3R) and the chemokine CCL2. Here we demonstrated for the first time that CXCL16 exerts a modulatory activity on inhibitory and excitatory synaptic transmission in CA1 area. We found that CXCL16 increases the frequency of the miniature inhibitory synaptic currents (mIPSCs) and the paired-pulse ratio (PPR) of evoked IPSCs (eIPSCs), suggesting a presynaptic modulation of the probability of GABA release. In addition, CXCL16 increases the frequency of the miniature excitatory synaptic currents (mEPSCs) and reduces the PPR of evoked excitatory transmission, indicating that the chemokine also modulates and enhances the release of glutamate. These effects were not present in the A3RKO mice and in WT slices treated with minocycline, confirming the involvement of A3 receptors and introducing microglial cells as key mediators of the modulatory activity of CXCL16 on neurons.
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CX3CL1/CX3CR1 in Alzheimer's Disease: A Target for Neuroprotection. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8090918. [PMID: 27429982 PMCID: PMC4939332 DOI: 10.1155/2016/8090918] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/05/2016] [Indexed: 12/31/2022]
Abstract
CX3C chemokine ligand 1 (CX3CL1) is an intriguing chemokine belonging to the CX3C family. CX3CL1 is secreted by neurons and plays an important role in modulating glial activation in the central nervous system after binding to its sole receptor CX3CR1 which mainly is expressed on microglia. Emerging data highlights the beneficial potential of CX3CL1-CX3CR1 in the pathogenesis of Alzheimer's disease (AD), a common progressive neurodegenerative disease, and in the progression of which neuroinflammation plays a vital role. Even so, the importance of CX3CL1/CX3CR1 in AD is still controversial and needs further clarification. In this review, we make an attempt to present a concise map of CX3CL1-CX3CR1 associated with AD to find biomarkers for early diagnosis or therapeutic interventions.
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Wu Y, Dissing-Olesen L, MacVicar BA, Stevens B. Microglia: Dynamic Mediators of Synapse Development and Plasticity. Trends Immunol 2016; 36:605-613. [PMID: 26431938 DOI: 10.1016/j.it.2015.08.008] [Citation(s) in RCA: 469] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 12/25/2022]
Abstract
Neuronal communication underlies all brain activity and the genesis of complex behavior. Emerging research has revealed an unexpected role for immune molecules in the development and plasticity of neuronal synapses. Moreover microglia, the resident immune cells of the brain, express and secrete immune-related signaling molecules that alter synaptic transmission and plasticity in the absence of inflammation. When inflammation does occur, microglia modify synaptic connections and synaptic plasticity required for learning and memory. Here we review recent findings demonstrating how the dynamic interactions between neurons and microglia shape the circuitry of the nervous system in the healthy brain and how altered neuron-microglia signaling could contribute to disease.
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Affiliation(s)
- Yuwen Wu
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02215, USA; These authors contributed equally to this work
| | - Lasse Dissing-Olesen
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 2B5, Canada; These authors contributed equally to this work
| | - Brian A MacVicar
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Beth Stevens
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02215, USA.
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17
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Di Angelantonio S, Bertollini C, Piccinin S, Rosito M, Trettel F, Pagani F, Limatola C, Ragozzino D. Basal adenosine modulates the functional properties of AMPA receptors in mouse hippocampal neurons through the activation of A1R A2AR and A3R. Front Cell Neurosci 2015; 9:409. [PMID: 26528137 PMCID: PMC4601258 DOI: 10.3389/fncel.2015.00409] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/25/2015] [Indexed: 11/30/2022] Open
Abstract
Adenosine is a widespread neuromodulator within the CNS and its extracellular level is increased during hypoxia or intense synaptic activity, modulating pre- and postsynaptic sites. We studied the neuromodulatory action of adenosine on glutamatergic currents in the hippocampus, showing that activation of multiple adenosine receptors (ARs) by basal adenosine impacts postsynaptic site. Specifically, the stimulation of both A1R and A3R reduces AMPA currents, while A2AR has an opposite potentiating effect. The effect of ARs stimulation on glutamatergic currents in hippocampal cultures was investigated using pharmacological and genetic approaches. A3R inhibition by MRS1523 increased GluR1-Ser845 phosphorylation and potentiated AMPA current amplitude, increasing the apparent affinity for the agonist. A similar effect was observed blocking A1R with DPCPX or by genetic deletion of either A3R or A1R. Conversely, impairment of A2AR reduced AMPA currents, and decreased agonist sensitivity. Consistently, in hippocampal slices, ARs activation by AR agonist NECA modulated glutamatergic current amplitude evoked by AMPA application or afferent fiber stimulation. Opposite effects of AR subtypes stimulation are likely associated to changes in GluR1 phosphorylation and represent a novel mechanism of physiological modulation of glutamatergic transmission by adenosine, likely acting in normal conditions in the brain, depending on the level of extracellular adenosine and the distribution of AR subtypes.
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Affiliation(s)
- Silvia Di Angelantonio
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy ; Center for Life Nanoscience, Istituto Italiano di Tecnologia Rome, Italy
| | - Cristina Bertollini
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy
| | - Sonia Piccinin
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy
| | - Maria Rosito
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy
| | - Flavia Trettel
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy
| | - Francesca Pagani
- Center for Life Nanoscience, Istituto Italiano di Tecnologia Rome, Italy
| | - Cristina Limatola
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy ; Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico Pozzilli, Italy
| | - Davide Ragozzino
- Istituto Pasteur-Fondazione Cenci Bolognetti and Dipartimento di Fisiologia e Farmacologia, Sapienza Università di Roma Roma, Italy ; Neuromed, Istituto di Ricovero e Cura a Carattere Scientifico Pozzilli, Italy
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18
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Stuart MJ, Singhal G, Baune BT. Systematic Review of the Neurobiological Relevance of Chemokines to Psychiatric Disorders. Front Cell Neurosci 2015; 9:357. [PMID: 26441528 PMCID: PMC4564736 DOI: 10.3389/fncel.2015.00357] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/26/2015] [Indexed: 12/13/2022] Open
Abstract
Psychiatric disorders are highly prevalent and disabling conditions of increasing public health relevance. Much recent research has focused on the role of cytokines in the pathophysiology of psychiatric disorders; however, the related family of immune proteins designated chemokines has been relatively neglected. Chemokines were originally identified as having chemotactic function on immune cells; however, recent evidence has begun to elucidate novel, brain-specific functions of these proteins of relevance to the mechanisms of psychiatric disorders. A systematic review of both human and animal literature in the PubMed and Google Scholar databases was undertaken. After application of all inclusion and exclusion criteria, 157 references were remained for the review. Some early mechanistic evidence does associate select chemokines with the neurobiological processes, including neurogenesis, modulation of the neuroinflammatory response, regulation of the hypothalamus–pituitary–adrenal axis, and modulation of neurotransmitter systems. This early evidence however does not clearly demonstrate any specificity for a certain psychiatric disorder, but is primarily relevant to mechanisms which are shared across disorders. Notable exceptions include CCL11 that has recently been shown to impair hippocampal function in aging – of distinct relevance to Alzheimer’s disease and depression in the elderly, and pre-natal exposure to CXCL8 that may disrupt early neurodevelopmental periods predisposing to schizophrenia. Pro-inflammatory chemokines, such as CCL2, CCL7, CCL8, CCL12, and CCL13, have been shown to drive chemotaxis of pro-inflammatory cells to the inflamed or injured CNS. Likewise, CX3CL has been implicated in promoting glial cells activation, pro-inflammatory cytokines secretion, expression of ICAM-1, and recruitment of CD4+ T-cells into the CNS during neuroinflammatory processes. With further translational research, chemokines may present novel diagnostic and/or therapeutic targets in psychiatric disorders.
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Affiliation(s)
- Michael J Stuart
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia ; School of Medicine, University of Queensland , Brisbane, QLD , Australia
| | - Gaurav Singhal
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia
| | - Bernhard T Baune
- Psychiatric Neuroscience Lab, Discipline of Psychiatry, University of Adelaide , Adelaide, SA , Australia
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Dworzak J, Renvoisé B, Habchi J, Yates EV, Combadière C, Knowles TP, Dobson CM, Blackstone C, Paulsen O, Murphy PM. Neuronal Cx3cr1 Deficiency Protects against Amyloid β-Induced Neurotoxicity. PLoS One 2015; 10:e0127730. [PMID: 26038823 PMCID: PMC4454597 DOI: 10.1371/journal.pone.0127730] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 04/20/2015] [Indexed: 01/06/2023] Open
Abstract
Cx3cr1, the receptor for the chemokine Cx3cl1 (fractalkine), has been implicated in the progression and severity of Alzheimer's disease-like pathology in mice, but the underlying mechanisms remain unclear. A complicating factor is that Cx3cr1 has been demonstrated in both neurons and microglia. Here, we have dissected the differences between neuronal and microglial Cx3cr1, specifically by comparing direct amyloid-β-induced toxicity in cultured, mature, microglia-depleted hippocampal neurons from wild-type and Cx3cr1-/- mice. Wild-type neurons expressed both Cx3cl1 and Cx3cr1 and released Cx3cl1 in response to amyloid-β. Knockout of neuronal Cx3cr1 abated amyloid-β-induced lactate dehydrogenase release. Furthermore, amyloid-β differentially induced depression of pre- and postsynaptic components of miniature excitatory postsynaptic currents, in a peptide conformation-dependent manner. Knockout of neuronal Cx3cr1 abated effects of both amyloid-β conformational states, which were differentiable by aggregation kinetics and peptide morphology. We obtained similar results after both acute and chronic treatment of cultured neurons with the Cx3cr1 antagonist F1. Thus, neuronal Cx3cr1 may impact Alzheimer's disease-like pathology by modulating conformational state-dependent amyloid-β-induced synaptotoxicity.
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Affiliation(s)
- Jenny Dworzak
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- Neuronal Oscillations Group, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Benoît Renvoisé
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Johnny Habchi
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Emma V. Yates
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christophe Combadière
- Centre d'Immunologie et des Maladies Infectieuses-Paris, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Tuomas P. Knowles
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ole Paulsen
- Neuronal Oscillations Group, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (PMM); (OP)
| | - Philip M. Murphy
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (PMM); (OP)
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20
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Huang Y, Thathiah A. Regulation of neuronal communication by G protein-coupled receptors. FEBS Lett 2015; 589:1607-19. [PMID: 25980603 DOI: 10.1016/j.febslet.2015.05.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 02/06/2023]
Abstract
Neuronal communication plays an essential role in the propagation of information in the brain and requires a precisely orchestrated connectivity between neurons. Synaptic transmission is the mechanism through which neurons communicate with each other. It is a strictly regulated process which involves membrane depolarization, the cellular exocytosis machinery, neurotransmitter release from synaptic vesicles into the synaptic cleft, and the interaction between ion channels, G protein-coupled receptors (GPCRs), and downstream effector molecules. The focus of this review is to explore the role of GPCRs and G protein-signaling in neurotransmission, to highlight the function of GPCRs, which are localized in both presynaptic and postsynaptic membrane terminals, in regulation of intrasynaptic and intersynaptic communication, and to discuss the involvement of astrocytic GPCRs in the regulation of neuronal communication.
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Affiliation(s)
- Yunhong Huang
- VIB Center for the Biology of Disease, Leuven, Belgium; Center for Human Genetics (CME) and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KUL), Leuven, Belgium.
| | - Amantha Thathiah
- VIB Center for the Biology of Disease, Leuven, Belgium; Center for Human Genetics (CME) and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KUL), Leuven, Belgium.
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21
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Pagani F, Paolicelli RC, Murana E, Cortese B, Di Angelantonio S, Zurolo E, Guiducci E, Ferreira TA, Garofalo S, Catalano M, D'Alessandro G, Porzia A, Peruzzi G, Mainiero F, Limatola C, Gross CT, Ragozzino D. Defective microglial development in the hippocampus of Cx3cr1 deficient mice. Front Cell Neurosci 2015; 9:111. [PMID: 25873863 PMCID: PMC4379915 DOI: 10.3389/fncel.2015.00111] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/11/2015] [Indexed: 11/13/2022] Open
Abstract
Microglial cells participate in brain development and influence neuronal loss and synaptic maturation. Fractalkine is an important neuronal chemokine whose expression increases during development and that can influence microglia function via the fractalkine receptor, CX3CR1. Mice lacking Cx3cr1 show a variety of neuronal defects thought to be the result of deficient microglia function. Activation of CX3CR1 is important for the proper migration of microglia to sites of injury and into the brain during development. However, little is known about how fractalkine modulates microglial properties during development. Here we examined microglial morphology, response to ATP, and K+ current properties in acute brain slices from Cx3cr1 knockout mice across postnatal hippocampal development. We found that fractalkine signaling is necessary for the development of several morphological and physiological features of microglia. Specifically, we found that the occurrence of an outward rectifying K+ current, typical of activated microglia, that peaked during the second and third postnatal week, was reduced in Cx3cr1 knockout mice. Fractalkine signaling also influenced microglial morphology and ability to extend processes in response to ATP following its focal application to the slice. Our results reveal the developmental profile of several morphological and physiological properties of microglia and demonstrate that these processes are modulated by fractalkine signaling.
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Affiliation(s)
- Francesca Pagani
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zürich, Zürich Switzerland ; Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Emanuele Murana
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Barbara Cortese
- Consiglio Nazionale delle Ricerche - Institute of Inorganic Methodologies and Plasmas, Department of Physics, Sapienza University of Rome, Rome Italy
| | - Silvia Di Angelantonio
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy ; Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Emanuele Zurolo
- Department of Neuropathology, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Eva Guiducci
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Tiago A Ferreira
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy
| | - Myriam Catalano
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Giuseppina D'Alessandro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Alessandra Porzia
- Department of Molecular Medicine, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome Rome, Italy
| | - Giovanna Peruzzi
- Center for Life Nanoscience - Istituto Italiano di Tecnologia@Sapienza, Rome Italy
| | - Fabrizio Mainiero
- Department of Experimental Medicine, Sapienza University of Rome Rome, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
| | - Cornelius T Gross
- Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome Italy ; Istituto di Ricovero e Cura a Carattere Scientifico Neuromed Pozzilli, Italy
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22
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Bian C, Zhao ZQ, Zhang YQ, Lü N. Involvement of CX3CL1/CX3CR1 signaling in spinal long term potentiation. PLoS One 2015; 10:e0118842. [PMID: 25768734 PMCID: PMC4358970 DOI: 10.1371/journal.pone.0118842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/14/2015] [Indexed: 12/30/2022] Open
Abstract
The long-term potentiation (LTP) of spinal C-fiber-evoked field potentials is considered as a fundamental mechanism of central sensitization in the spinal cord. Accumulating evidence has showed the contribution of spinal microglia to spinal LTP and pathological pain. As a key signaling of neurons-microglia interactions, the involvement of CX3CL1/CX3CR1 signaling in pathological pain has also been investigated extensively. The present study examined whether CX3CL1/CX3CR1 signaling plays a role in spinal LTP. The results showed that 10-trains tetanic stimulation (100 Hz, 2s) of the sciatic nerve (TSS) produced a significant LTP of C-fiber-evoked field potentials lasting for over 3 h in the rat spinal dorsal horn. Blockade of CX3CL1/CX3CR1 signaling with an anti-CX3CR1 neutralizing antibody (CX3CR1 AB) markedly suppressed TSS-induced LTP. Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats. Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice. However, in CX3CR1-/- mice, TSS failed to induce LTP and behavioral hypersensitivity, confirming an essential role of CX3CR1 in spinal LTP induction. Furthermore, blockade of IL-18 or IL-23, the potential downstream factors of CX3CL1/CX3CR1 signaling, with IL-18 BP or anti-IL-23 neutralizing antibody (IL-23 AB), obviously suppressed spinal LTP in rats. These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.
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Affiliation(s)
- Chao Bian
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhi-Qi Zhao
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Yu-Qiu Zhang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
- * E-mail: (NL); (YQZ)
| | - Ning Lü
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
- * E-mail: (NL); (YQZ)
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23
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Ali I, Chugh D, Ekdahl CT. Role of fractalkine-CX3CR1 pathway in seizure-induced microglial activation, neurodegeneration, and neuroblast production in the adult rat brain. Neurobiol Dis 2014; 74:194-203. [PMID: 25461978 DOI: 10.1016/j.nbd.2014.11.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/21/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022] Open
Abstract
Temporal lobe seizures lead to an acute inflammatory response in the brain primarily characterized by activation of parenchymal microglial cells. Simultaneously, degeneration of pyramidal cells and interneurons is evident together with a seizure-induced increase in the production of new neurons within the dentate gyrus of the hippocampus. We have previously shown a negative correlation between the acute seizure-induced inflammation and the survival of newborn hippocampal neurons. Here, we aimed to evaluate the role of the fractalkine-CX3CR1 pathway for these acute events. Fractalkine is a chemokine expressed by both neurons and glia, while its receptor, CX3CR1 is primarily expressed on microglia. Electrically-induced partial status epilepticus (SE) was induced in adult rats through stereotaxically implanted electrodes in the hippocampus. Recombinant rat fractalkine or CX3CR1 antibody was infused intraventricularly during one week post-SE. A significant increase in the expression of CX3CR1, but not fractalkine, was observed in the dentate gyrus at one week. CX3CR1 antibody treatment resulted in a reduction in microglial activation, neurodegeneration, as well as neuroblast production. In contrast, fractalkine treatment had only minor effects. This study provides evidence for a role of the fractalkine-CX3CR1 signaling pathway in seizure-induced microglial activation and suggests that neuroblast production following seizures may partly occur as a result of microglial activation.
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Affiliation(s)
- Idrish Ali
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden
| | - Deepti Chugh
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden
| | - Christine T Ekdahl
- Inflammation and Stem Cell Therapy Group, Wallenberg Neuroscience Center, Division of Clinical Neurophysiology, Lund University, Sweden; Lund Epilepsy Center, Lund University, SE-221 84 Lund, Sweden.
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24
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Sheridan GK, Wdowicz A, Pickering M, Watters O, Halley P, O'Sullivan NC, Mooney C, O'Connell DJ, O'Connor JJ, Murphy KJ. CX3CL1 is up-regulated in the rat hippocampus during memory-associated synaptic plasticity. Front Cell Neurosci 2014; 8:233. [PMID: 25161610 PMCID: PMC4130185 DOI: 10.3389/fncel.2014.00233] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/25/2014] [Indexed: 11/13/2022] Open
Abstract
Several cytokines and chemokines are now known to play normal physiological roles in the brain where they act as key regulators of communication between neurons, glia, and microglia. In particular, cytokines and chemokines can affect cardinal cellular and molecular processes of hippocampal-dependent long-term memory consolidation including synaptic plasticity, synaptic scaling and neurogenesis. The chemokine, CX3CL1 (fractalkine), has been shown to modulate synaptic transmission and long-term potentiation (LTP) in the CA1 pyramidal cell layer of the hippocampus. Here, we confirm widespread expression of CX3CL1 on mature neurons in the adult rat hippocampus. We report an up-regulation in CX3CL1 protein expression in the CA1, CA3 and dentate gyrus (DG) of the rat hippocampus 2 h after spatial learning in the water maze task. Moreover, the same temporal increase in CX3CL1 was evident following LTP-inducing theta-burst stimulation in the DG. At physiologically relevant concentrations, CX3CL1 inhibited LTP maintenance in the DG. This attenuation in dentate LTP was lost in the presence of GABAA receptor/chloride channel antagonism. CX3CL1 also had opposing actions on glutamate-mediated rise in intracellular calcium in hippocampal organotypic slice cultures in the presence and absence of GABAA receptor/chloride channel blockade. Using primary dissociated hippocampal cultures, we established that CX3CL1 reduces glutamate-mediated intracellular calcium rises in both neurons and glia in a dose dependent manner. In conclusion, CX3CL1 is up-regulated in the hippocampus during a brief temporal window following spatial learning the purpose of which may be to regulate glutamate-mediated neurotransmission tone. Our data supports a possible role for this chemokine in the protective plasticity process of synaptic scaling.
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Affiliation(s)
- Graham K Sheridan
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland ; Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK
| | - Anita Wdowicz
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Mark Pickering
- School of Medicine and Medical Science, Health Sciences Centre, University College Dublin Dublin, Ireland
| | - Orla Watters
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Paul Halley
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Claire Mooney
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - David J O'Connell
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - John J O'Connor
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
| | - Keith J Murphy
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin Dublin, Ireland
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26
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Paolicelli RC, Bisht K, Tremblay MÈ. Fractalkine regulation of microglial physiology and consequences on the brain and behavior. Front Cell Neurosci 2014; 8:129. [PMID: 24860431 PMCID: PMC4026677 DOI: 10.3389/fncel.2014.00129] [Citation(s) in RCA: 214] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/24/2014] [Indexed: 11/16/2022] Open
Abstract
Neural circuits are constantly monitored and supported by the surrounding microglial cells, using finely tuned mechanisms which include both direct contact and release of soluble factors. These bidirectional interactions are not only triggered by pathological conditions as a S.O.S. response to noxious stimuli, but they rather represent an established repertoire of dynamic communication for ensuring continuous immune surveillance and homeostasis in the healthy brain. In addition, recent studies are revealing key tasks for microglial interactions with neurons during normal physiological conditions, especially in regulating the maturation of neural circuits and shaping their connectivity in an activity- and experience-dependent manner. Chemokines, a family of soluble and membrane-bound cytokines, play an essential role in mediating neuron-microglia crosstalk in the developing and mature brain. As part of this special issue on Cytokines as players of neuronal plasticity and sensitivity to environment in healthy and pathological brain, our review focuses on the fractalkine signaling pathway, involving the ligand CX3CL1 which is mainly expressed by neurons, and its receptor CX3CR1 that is exclusively found on microglia within the healthy brain. An extensive literature largely based on transgenic mouse models has revealed that fractalkine signaling plays a critical role in regulating a broad spectrum of microglial properties during normal physiological conditions, especially their migration and dynamic surveillance of the brain parenchyma, in addition to influencing the survival of developing neurons, the maturation, activity and plasticity of developing and mature synapses, the brain functional connectivity, adult hippocampal neurogenesis, as well as learning and memory, and the behavioral outcome.
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Affiliation(s)
| | - Kanchan Bisht
- Axe Neurosciences, Centre de Recherche du CHU de Québec Québec, Canada ; Department of Molecular Medicine, Université Laval Québec, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec Québec, Canada ; Department of Molecular Medicine, Université Laval Québec, Canada
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Audinat E, Arnoux I. [Microglia: immune cells sculpting and controlling neuronal synapses]. Med Sci (Paris) 2014; 30:153-9. [PMID: 24572113 DOI: 10.1051/medsci/20143002012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The development of new animal models and functional analysis methods has dramatically changed our understanding of the physiology of microglial cells. These cells which are the resident macrophages of central nervous system have the ability to adapt rapidly to subtle changes of their environment. Recent findings indicate in particular that they can establish contacts with neuronal synapses that they can eliminate and modulate by releasing specific mediators. Here we review the experimental observations that have revealed the occurrence of these interactions not only in pathological conditions but also in the healthy brain and in particular during normal brain development. The discovery of bi-directional communications between synapses and microglia sheds a new light on our understanding of brain functioning and should allow a better understanding of brain functioning and of interactions between immune and nervous systems.
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Affiliation(s)
- Etienne Audinat
- Inserm U1128, Paris, France ; Université Paris Descartes, laboratoire de neurophysiologie et nouvelles microscopies, 45, rue des Saints-Pères, 75006 Paris, France
| | - Isabelle Arnoux
- Inserm U1128, Paris, France ; Université Paris Descartes, laboratoire de neurophysiologie et nouvelles microscopies, 45, rue des Saints-Pères, 75006 Paris, France
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Chen JF. Adenosine receptor control of cognition in normal and disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 119:257-307. [PMID: 25175970 DOI: 10.1016/b978-0-12-801022-8.00012-x] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Adenosine and adenosine receptors (ARs) are increasingly recognized as important therapeutic targets for controlling cognition under normal and disease conditions for its dual roles of neuromodulation as well as of homeostatic function in the brain. This chapter first presents the unique ability of adenosine, by acting on the inhibitory A1 and facilitating A2A receptor, to integrate dopamine, glutamate, and BNDF signaling and to modulate synaptic plasticity (e.g., long-term potentiation and long-term depression) in brain regions relevant to learning and memory, providing the molecular and cellular bases for adenosine receptor (AR) control of cognition. This led to the demonstration of AR modulation of social recognition memory, working memory, reference memory, reversal learning, goal-directed behavior/habit formation, Pavlovian fear conditioning, and effort-related behavior. Furthermore, human and animal studies support that AR activity can also, through cognitive enhancement and neuroprotection, reverse cognitive impairments in animal models of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, and schizophrenia. Lastly, epidemiological evidence indicates that regular human consumption of caffeine, the most widely used psychoactive drug and nonselective AR antagonists, is associated with the reduced cognitive decline in aging and AD patients, and with the reduced risk in developing PD. Thus, there is a convergence of the molecular studies revealing AR as molecular targets for integrating neurotransmitter signaling and controlling synaptic plasticity, with animal studies demonstrating the strong procognitive impact upon AR antagonism in normal and disease brains and with epidemiological and clinical evidences in support of caffeine and AR drugs for therapeutic modulation of cognition. Since some of adenosine A2A receptor antagonists are already in phase III clinical trials for motor benefits in PD patients with remarkable safety profiles, additional animal and human studies to better understand the mechanism underlying the AR-mediated control of cognition under normal and disease conditions will provide the required rationale to stimulate the necessary clinical investigation to rapidly translate adenosine and AR drug as a novel strategy to control memory impairment in neuropsychiatric disorders.
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Affiliation(s)
- Jiang-Fan Chen
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA; The Molecular Medicine Institute, Wenzhou Medical University, Wenzhou, Zhejiang, PR China.
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Sheridan GK, Murphy KJ. Neuron-glia crosstalk in health and disease: fractalkine and CX3CR1 take centre stage. Open Biol 2013; 3:130181. [PMID: 24352739 PMCID: PMC3877844 DOI: 10.1098/rsob.130181] [Citation(s) in RCA: 236] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
An essential aspect of normal brain function is the bidirectional interaction and communication between neurons and neighbouring glial cells. To this end, the brain has evolved ligand-receptor partnerships that facilitate crosstalk between different cell types. The chemokine, fractalkine (FKN), is expressed on neuronal cells, and its receptor, CX(3)CR1, is predominantly expressed on microglia. This review focuses on several important functional roles for FKN/CX(3)CR1 in both health and disease of the central nervous system. It has been posited that FKN is involved in microglial infiltration of the brain during development. Microglia, in turn, are implicated in the developmental synaptic pruning that occurs during brain maturation. The abundance of FKN on mature hippocampal neurons suggests a homeostatic non-inflammatory role in mechanisms of learning and memory. There is substantial evidence describing a role for FKN in hippocampal synaptic plasticity. FKN, on the one hand, appears to prevent excess microglial activation in the absence of injury while promoting activation of microglia and astrocytes during inflammatory episodes. Thus, FKN appears to be neuroprotective in some settings, whereas it contributes to neuronal damage in others. Many progressive neuroinflammatory disorders that are associated with increased microglial activation, such as Alzheimer's disease, show disruption of the FKN/CX(3)CR1 communication system. Thus, targeting CX(3)CR1 receptor hyperactivation with specific antagonists in such neuroinflammatory conditions may eventually lead to novel neurotherapeutics.
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Affiliation(s)
- Graham K Sheridan
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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Ferrini F, De Koninck Y. Microglia control neuronal network excitability via BDNF signalling. Neural Plast 2013; 2013:429815. [PMID: 24089642 PMCID: PMC3780625 DOI: 10.1155/2013/429815] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 07/28/2013] [Indexed: 12/27/2022] Open
Abstract
Microglia-neuron interactions play a crucial role in several neurological disorders characterized by altered neural network excitability, such as epilepsy and neuropathic pain. While a series of potential messengers have been postulated as substrates of the communication between microglia and neurons, including cytokines, purines, prostaglandins, and nitric oxide, the specific links between messengers, microglia, neuronal networks, and diseases have remained elusive. Brain-derived neurotrophic factor (BDNF) released by microglia emerges as an exception in this riddle. Here, we review the current knowledge on the role played by microglial BDNF in controlling neuronal excitability by causing disinhibition. The efforts made by different laboratories during the last decade have collectively provided a robust mechanistic paradigm which elucidates the mechanisms involved in the synthesis and release of BDNF from microglia, the downstream TrkB-mediated signals in neurons, and the biophysical mechanism by which disinhibition occurs, via the downregulation of the K⁺-Cl⁻ cotransporter KCC2, dysrupting Cl⁻ homeostasis, and hence the strength of GABA(A)- and glycine receptor-mediated inhibition. The resulting altered network activity appears to explain several features of the associated pathologies. Targeting the molecular players involved in this canonical signaling pathway may lead to novel therapeutic approach for ameliorating a wide array of neural dysfunctions.
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Affiliation(s)
- Francesco Ferrini
- Department of Veterinary Sciences, University of Turin, Grugliasco, 10095 Turin, Italy
| | - Yves De Koninck
- Institut Universitaire en Santé Mentale de Québec, Québec, QC, Canada G1J 2G3
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada G13 7P4
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Scianni M, Antonilli L, Chece G, Cristalli G, Di Castro MA, Limatola C, Maggi L. Fractalkine (CX3CL1) enhances hippocampal N-methyl-D-aspartate receptor (NMDAR) function via D-serine and adenosine receptor type A2 (A2AR) activity. J Neuroinflammation 2013; 10:108. [PMID: 23981568 PMCID: PMC3765929 DOI: 10.1186/1742-2094-10-108] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 05/28/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND N-Methyl-D-aspartate receptors (NMDARs) play fundamental roles in basic brain functions such as excitatory neurotransmission and learning and memory processes. Their function is largely regulated by factors released by glial cells, including the coagonist d-serine. We investigated whether the activation of microglial CX3CR1 induces the release of factors that modulate NMDAR functions. METHODS We recorded the NMDAR component of the field excitatory postsynaptic potentials (NMDA-fEPSPs) elicited in the CA1 stratum radiatum of mouse hippocampal slices by Shaffer collateral stimulation and evaluated D-serine content in the extracellular medium of glial primary cultures by mass spectrometry analysis. RESULTS We demonstrated that CX3CL1 increases NMDA-fEPSPs by a mechanism involving the activity of the adenosine receptor type A2 (A2AR) and the release of the NMDAR coagonist D-serine. Specifically (1) the selective A2AR blocker 7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH58261) and the genetic ablation of A2AR prevent CX3CL1 action while the A2AR agonist 5-(6-amino-2-(phenethylthio)-9H-purin-9-yl)-N-ethyl-3,4-dihydroxytetrahydrofuran-2-carboxamide (VT7) mimics CX3CL1 effect, and (2) the selective blocking of the NMDAR glycine (and D-serine) site by 5,7-dicholorokynurenic acid (DCKA), the enzymatic degradation of D-serine by D-amino acid oxidase (DAAO) and the saturation of the coagonist site by D-serine, all block the CX3CL1 effect. In addition, mass spectrometry analysis demonstrates that stimulation of microglia and astrocytes with CX3CL1 or VT7 increases D-serine release in the extracellular medium. CONCLUSIONS CX3CL1 transiently potentiates NMDAR function though mechanisms involving A2AR activity and the release of D-serine.
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Affiliation(s)
- Maria Scianni
- Institute Pasteur-Cenci Bolognetti Foundation, Department of Physiology and Pharmacology, University Sapienza, Rome, Italy.
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Béchade C, Cantaut-Belarif Y, Bessis A. Microglial control of neuronal activity. Front Cell Neurosci 2013; 7:32. [PMID: 23543873 PMCID: PMC3610058 DOI: 10.3389/fncel.2013.00032] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/13/2013] [Indexed: 01/27/2023] Open
Abstract
Fine-tuning of neuronal activity was thought to be a neuron-autonomous mechanism until the discovery that astrocytes are active players of synaptic transmission. The involvement of astrocytes has changed our understanding of the roles of non-neuronal cells and shed new light on the regulation of neuronal activity. Microglial cells are the macrophages of the brain and they have been mostly investigated as immune cells. However, recent data discussed in this review support the notion that, similarly to astrocytes, microglia are involved in the regulation of neuronal activity. For instance, in most, if not all, brain pathologies a strong temporal correlation has long been known to exist between the pathological activation of microglia and dysfunction of neuronal activity. Recent studies have convincingly shown that alteration of microglial function is responsible for pathological neuronal activity. This causal relationship has also been demonstrated in mice bearing loss-of-function mutations in genes specifically expressed by microglia. In addition to these long-term regulations of neuronal activity, recent data show that microglia can also rapidly regulate neuronal activity, thereby acting as partners of neurotransmission.
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Affiliation(s)
- Catherine Béchade
- Institut de Biologie, Ecole Normale Supérieure, Inserm U1025, CNRS UMR8197 Paris, France
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Rostène W, Dansereau MA, Godefroy D, Van Steenwinckel J, Goazigo ARL, Mélik-Parsadaniantz S, Apartis E, Hunot S, Beaudet N, Sarret P. Neurochemokines: a menage a trois providing new insights on the functions of chemokines in the central nervous system. J Neurochem 2011; 118:680-94. [DOI: 10.1111/j.1471-4159.2011.07371.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Baines AE, Corrêa SAL, Irving AJ, Frenguelli BG. Differential trafficking of adenosine receptors in hippocampal neurons monitored using GFP- and super-ecliptic pHluorin-tagged receptors. Neuropharmacology 2011; 61:1-11. [PMID: 21315741 DOI: 10.1016/j.neuropharm.2011.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/28/2011] [Accepted: 02/02/2011] [Indexed: 01/18/2023]
Abstract
Adenosine receptors (ARs) modulate many cellular and systems-level processes in the mammalian CNS. However, little is known about the trafficking of ARs in neurons, despite their importance in controlling seizure activity and in neuroprotection in cerebral ischaemia. To address this we examined the agonist-dependent internalisation of C-terminal GFP-tagged A(1)Rs, A(2A)Rs and A(3)Rs in primary hippocampal neurons. Furthermore, we developed a novel super-ecliptic pHluorin (SEP)-tagged A(1)R which, via the N-terminal SEP tag, reports the cell-surface expression and trafficking of A(1)Rs in real-time. We demonstrate the differential trafficking of ARs in neurons: A(3)Rs internalise more rapidly than A1Rs, with little evidence of appreciable A(2A)R trafficking over the time-course of the experiments. Furthermore, the novel SEP-A(1)R construct revealed the time-course of internalisation and recovery of cell-surface expression to occur within minutes of agonist exposure and removal, respectively. These observations highlight the labile nature of A(1)R and A(3)Rs when expressed at the neuronal plasma membrane. Given the high levels of adenosine in the brain during ischaemia and seizures, internalisation of the inhibitory A(1)R may result in hyperexcitability, increased brain damage and the development of chronic epileptic states.
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Affiliation(s)
- A E Baines
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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Wei CJ, Li W, Chen JF. Normal and abnormal functions of adenosine receptors in the central nervous system revealed by genetic knockout studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1358-79. [PMID: 21185258 DOI: 10.1016/j.bbamem.2010.12.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 12/14/2010] [Accepted: 12/15/2010] [Indexed: 12/17/2022]
Abstract
Endogenous adenosine is a widely distributed upstream regulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways that converge to contribute to the expression of an array of important brain functions. Over the past decade, the generation and characterization of genetic knockout models for all four G-protein coupled adenosine receptors, the A1 and A2A receptors in particular, has confirmed and extended the neuromodulatory and integrated role of adenosine receptors in the control of a broad spectrum of normal and abnormal brain functions. After a brief introduction of the available adenosine receptor knockout models, this review focuses on findings from the genetic knockout approach, placing particular emphasis on the most recent findings. This review is organized into two sections to separately address (i) the role of adenosine receptors in normal brain processes including neuroplasticity, sleep-wake cycle, motor function, cognition, and emotion-related behaviors; and (ii) their role in the response to various pathologic insults to brain such as ischemic stroke, neurodegeneration, or brain dysfunction/disorders. We largely limit our overview to the prominent adenosine receptor subtypes in brain-the A1 and A2A receptors-for which numerous genetic knockout studies on brain function are available. A1 and A2A receptor knockouts have provided significant new insights into adenosine's control of complex physiologic (e.g., cognition) and pathologic (e.g., neuroinflammation) phenomena. These findings extend and strengthen the support for A1 and A2A receptors in brain as therapeutic targets in several neurologic and psychiatric diseases. However, they also emphasize the importance of considering the disease context-dependent effect when developing adenosine receptor-based therapeutic strategies.
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Affiliation(s)
- Catherine J Wei
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
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