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Role of Infiltrating Microglia/Macrophages in Glioma. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1202:281-298. [PMID: 32034719 DOI: 10.1007/978-3-030-30651-9_14] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter we describe the state of the art knowledge of the role played by myeloid cells in promoting and supporting the growth and the invasive properties of a deadly brain tumor, glioblastoma. We provide a review of the works describing the intercellular communication among glioma and associated microglia/macrophage cells (GAMs) using in vitro cellular models derived from mice, rats and human patients and in vivo animal models using syngeneic or xenogeneic experimental systems. Special emphasis will be given to 1) the timing alteration of brain microenvironment under the influence of glioma, 2) the bidirectional communication among tumor and GAMs, 3) possible approaches to interfere with or to guide these interactions, with the aim to identify molecular and cellular targets which could revert or delay the vicious cycle that favors tumor biology.
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Wan Y, Hua Y, Garton HJL, Novakovic N, Keep RF, Xi G. Activation of epiplexus macrophages in hydrocephalus caused by subarachnoid hemorrhage and thrombin. CNS Neurosci Ther 2019; 25:1134-1141. [PMID: 31433571 PMCID: PMC6776740 DOI: 10.1111/cns.13203] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 01/08/2023] Open
Abstract
Aims We have found that hydrocephalus development in spontaneously hypertensive rats was associated with activation of epiplexus cells. The current study examined whether epiplexus cell activation occurs in a rat subarachnoid hemorrhage (SAH), whether activation would be greater in a subset of rats that developed hydrocephalus and the potential role of thrombin in epiplexus cell activation. Methods There were two parts in this study. First, an endovascular perforation was performed in rats to induce SAH. Second, rats received an intraventricular infusion of either thrombin or saline. Magnetic resonance imaging was used to measure the ventricular volumes. Immunofluorescence and immunohistochemistry were used to study epiplexus cell activation. Results Iba‐1, OX‐6, and CD68 were expressed in the epiplexus cells of the choroid plexus in sham‐operated rats. SAH increased Iba‐1 and CD68 immunoreactivity in epiplexus cells in addition to an increase in Iba‐1‐positive cell soma size. Those effects were greater in rats that developed hydrocephalus. Intraventricular thrombin mimicked the effects of SAH on epiplexus cell activation and hydrocephalus. Conclusion This study supports the concept that epiplexus cell activation is associated with hydrocephalus development. Epiplexus cell activation may be in response to thrombin production after hemorrhage, and it may be a therapeutic target.
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Affiliation(s)
- Yingfeng Wan
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA.,Department of Neurosurgery, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China
| | - Ya Hua
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Hugh J L Garton
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Nemanja Novakovic
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Guohua Xi
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
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Eyo UB, Wu LJ. Microglia: Lifelong patrolling immune cells of the brain. Prog Neurobiol 2019; 179:101614. [PMID: 31075285 PMCID: PMC6599472 DOI: 10.1016/j.pneurobio.2019.04.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/11/2019] [Accepted: 04/19/2019] [Indexed: 02/02/2023]
Abstract
Microglial cells are the predominant parenchymal immune cell of the brain. Recent evidence suggests that like peripheral immune cells, microglia patrol the brain in health and disease. Reviewing these data, we first examine the evidence that microglia invade the brain mesenchyme early in embryonic development, establish residence therein, proliferate and subsequently maintain their numbers throughout life. We, then, summarize established and novel evidence for microglial process surveillance in the healthy and injured brain. Finally, we discuss emerging evidence for microglial cell body dynamics that challenge existing assumptions of their sessile nature. We conclude that microglia are long-lived immune cells that patrol the brain through both cell body and process movements. This recognition has significant implications for neuroimmune interactions throughout the animal lifespan.
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Affiliation(s)
- Ukpong B Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, USA; Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
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Zusso M, Lunardi V, Franceschini D, Pagetta A, Lo R, Stifani S, Frigo AC, Giusti P, Moro S. Ciprofloxacin and levofloxacin attenuate microglia inflammatory response via TLR4/NF-kB pathway. J Neuroinflammation 2019; 16:148. [PMID: 31319868 PMCID: PMC6637517 DOI: 10.1186/s12974-019-1538-9] [Citation(s) in RCA: 287] [Impact Index Per Article: 57.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/08/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Neuroinflammation is the response of the central nervous system to events that interfere with tissue homeostasis and represents a common denominator in virtually all neurological diseases. Activation of microglia, the principal immune effector cells of the brain, contributes to neuronal injury by release of neurotoxic products. Toll-like receptor 4 (TLR4), expressed on the surface of microglia, plays an important role in mediating lipopolysaccharide (LPS)-induced microglia activation and inflammatory responses. We have previously shown that curcumin and some of its analogues harboring an α,β-unsaturated 1,3-diketone moiety, able to coordinate the magnesium ion, can interfere with LPS-mediated TLR4-myeloid differentiation protein-2 (MD-2) signaling. Fluoroquinolone (FQ) antibiotics are compounds that contain a keto-carbonyl group that binds divalent ions, including magnesium. In addition to their antimicrobial activity, FQs are endowed with immunomodulatory properties, but the mechanism underlying their anti-inflammatory activity remains to be defined. The aim of the current study was to elucidate the molecular mechanism of these compounds in the TLR4/NF-κB inflammatory signaling pathway. METHODS The putative binding mode of five FQs [ciprofloxacin (CPFX), levofloxacin (LVFX), moxifloxacin, ofloxacin, and delafloxacin] to TLR4-MD-2 was determined using molecular docking simulations. The effect of CPFX and LVFX on LPS-induced release of IL-1β and TNF-α and NF-κB activation was investigated in primary microglia by ELISA and fluorescence staining. The interaction of CPFX and LVFX with TLR4-MD-2 complex was assessed by immunoprecipitation followed by Western blotting using Ba/F3 cells. RESULTS CPFX and LVFX bound to the hydrophobic region of the MD-2 pocket and inhibited LPS-induced secretion of pro-inflammatory cytokines and activation of NF-κB in primary microglia. Furthermore, these FQs diminished the binding of LPS to TLR4-MD-2 complex and decreased the resulting TLR4-MD-2 dimerization in Ba/F3 cells. CONCLUSIONS These results provide new insight into the mechanism of the anti-inflammatory activity of CPFX and LVFX, which involves, at least in part, the activation of TLR4/NF-κB signaling pathway. Our findings might facilitate the development of new molecules directed at the TLR4-MD-2 complex, a potential key target for controlling neuroinflammation.
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Affiliation(s)
- Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy
| | - Valentina Lunardi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy
| | - Davide Franceschini
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy.,Present address: Selvita S.A., Park Life Science ul, Bobrzyńskiego 14, 30-348, Kraków, Poland
| | - Andrea Pagetta
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy
| | - Rita Lo
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Stefano Stifani
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Anna Chiara Frigo
- Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua, Padua, Italy
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy.
| | - Stefano Moro
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy
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Microglia along sex lines: From brain colonization, maturation and function, to implication in neurodevelopmental disorders. Semin Cell Dev Biol 2019; 94:152-163. [PMID: 31201858 DOI: 10.1016/j.semcdb.2019.06.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 12/30/2022]
Abstract
In addition to their traditional role as immune sentinels, recent discoveries over the last decade have shown that microglial functions now include regulation of neuronal/glial cell migration, differentiation and maturation, as well as neuronal network formation. It was thus proposed that disruption of these microglial roles, during critical periods of brain development, could lead to the pathological onset of several neurodevelopmental disorders, including autism spectrum disorder, attention deficit hyperactivity disorder, epilepsy, schizophrenia, and major depressive disorder. The prevalence of these disorders exhibits a clear distinction along sex lines with very little known about the mechanisms underlying this difference. One of the fundamental discoveries that arose from recent research into the physiological roles of microglia in neurodevelopment is their sexual dimorphism, raising the intriguing possibility that sex differences in microglial colonization, maturation and/or function in the developing brain could underlie the emergence of various neurodevelopmental disorders. This review discusses the physiological roles of microglia across neurodevelopment, these roles in the two sexes, and the recent evidence that microglial sexually dimorphic nature may contribute, at least partially, to neurodevelopmental disorders.
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Smolders SMT, Kessels S, Vangansewinkel T, Rigo JM, Legendre P, Brône B. Microglia: Brain cells on the move. Prog Neurobiol 2019; 178:101612. [PMID: 30954517 DOI: 10.1016/j.pneurobio.2019.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, tremendous progress has been made in understanding the biology of microglia - i.e. the fascinating immigrated resident immune cell population of the central nervous system (CNS). Recent literature reviews have largely dealt with the plentiful functions of microglia in CNS homeostasis, development and pathology, and the influences of sex and the microbiome. In this review, the intriguing aspect of their physical plasticity during CNS development will get specific attention. Microglia move around (mobility) and reshape their processes (motility). Microglial migration into and inside the CNS is most prominent throughout development and consequently most of the data described in this review concern mobility and motility in the changing environment of the developing brain. Here, we first define microglia based on their highly specialized age- and region-dependent gene expression signature and associated functional heterogeneity. Next, we describe their origin, the migration route of immature microglial cells towards the CNS, the mechanisms underlying their invasion of the CNS, and their spatiotemporal localization and surveying behaviour inside the developing CNS. These processes are dependent on microglial mobility and motility which are determined by the microenvironment of the CNS. Therefore, we further zoom in on the changing environment during CNS development. We elaborate on the extracellular matrix and the respective integrin receptors on microglia and we discuss the purinergic and molecular signalling in microglial mobility. In the last section, we discuss the physiological and pathological functions of microglia in which mobility and motility are involved to stress the importance of microglial 'movement'.
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Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium; INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Pascal Legendre
- INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
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Reichert F, Rotshenker S. Galectin-3 (MAC-2) Controls Microglia Phenotype Whether Amoeboid and Phagocytic or Branched and Non-phagocytic by Regulating the Cytoskeleton. Front Cell Neurosci 2019; 13:90. [PMID: 30930748 PMCID: PMC6427835 DOI: 10.3389/fncel.2019.00090] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 02/22/2019] [Indexed: 11/13/2022] Open
Abstract
Myelin surrounding central nervous system (CNS) axons breaks down in multiple sclerosis (MS) and following traumatic axonal injury. Myelin-debris so produced is harmful to repair since it impedes remyelination in MS and the regeneration of traumatized axons. These devastating outcomes are largely due to inefficient removal by phagocytosis of myelin-debris by microglia. Therefore, revealing mechanisms that control phagocytosis is vital. We previously showed that in phagocytosis, filopodia and lamellipodia extend/engulf and then retract/internalize myelin-debris. Moreover, cofilin activates phagocytosis by advancing the remodeling of actin filaments (i.e., existing filaments disassemble and new filaments assemble in a new configuration), causing filopodia/lamellipodia to protrude, and furthermore, Galectin-3 (formally named MAC-2) activates phagocytosis by enhancing K-Ras.GTP/PI3K signaling that leads to actin/myosin-based contraction, causing filopodia/lamellipodia to retract. To understand further how Galectin-3 controls phagocytosis we knocked-down (KD) Galectin-3 expression in cultured primary microglia using Galectin-3 small-hairpin RNA (Gal-3-shRNA). KD Galectin-3 protein levels reduced phagocytosis extensively. Further, inhibiting nucleolin (NCL) and nucleophosmin (NPM), which advance K-Ras signaling as does Galectin-3, also reduced phagocytosis. Strikingly and unexpectedly, knocking down Galectin-3 resulted in a dramatic transformation of microglia morphology from “amoeboid-like” to “branched-like,” rearrangement of actin filaments and inactivation of cofilin. Thus, Galectin-3 may control microglia morphology and phagocytosis by regulating the activation state of cofilin, which, in turn, affects how actin filaments organize and how stable they are. Furthermore, our current and previous findings together suggest that Galectin-3 activates phagocytosis by targeting the cytoskeleton twice: first, by advancing cofilin activation, causing filopodia/lamellipodia to extend/engulf myelin-debris. Second, by advancing actin/myosin-based contraction through K-Ras.GTP/PI3K signaling, causing filopodia/lamellipodia to retract/internalize myelin-debris.
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Affiliation(s)
- Fanny Reichert
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Shlomo Rotshenker
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University, Jerusalem, Israel
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58
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Tay TL, Carrier M, Tremblay MÈ. Physiology of Microglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:129-148. [PMID: 31583587 DOI: 10.1007/978-981-13-9913-8_6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Microglia constitute the major immune cells that permanently reside in the central nervous system (CNS) alongside neurons and other glial cells. These resident immune cells are critical for proper brain development, actively maintain brain health throughout the lifespan and rapidly adapt their function to the physiological or pathophysiological needs of the organism. Cutting-edge fate mapping and imaging techniques applied to animal models enabled a revolution in our understanding of their roles during normal physiological conditions. Here, we highlight studies that demonstrate the embryonic yolk sac origin of microglia and describe factors, including crosstalk with the periphery and external environment, that regulate their differentiation, homeostasis and function in the context of healthy CNS. The diversity of microglial phenotypes observed across the lifespan, between brain compartments and between sexes is also discussed. Understanding what defines specific microglial phenotypes is critical for the development of innovative therapies to modulate their effector functions and improve clinical outcomes.
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Affiliation(s)
- Tuan Leng Tay
- Institute of Biology I, University of Freiburg, Hauptstr. 1, 79104, Freiburg, Germany. .,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany. .,Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104, Freiburg, Germany.
| | - Micaël Carrier
- Axe Neurosciences, Centre de Recherche du CHU de Québec, 2705, Boulevard Laurier, Québec, QC, G1V 4G2, Canada
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, 2705, Boulevard Laurier, Québec, QC, G1V 4G2, Canada.
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Litvinchuk A, Wan YW, Swartzlander DB, Chen F, Cole A, Propson NE, Wang Q, Zhang B, Liu Z, Zheng H. Complement C3aR Inactivation Attenuates Tau Pathology and Reverses an Immune Network Deregulated in Tauopathy Models and Alzheimer's Disease. Neuron 2018; 100:1337-1353.e5. [PMID: 30415998 PMCID: PMC6309202 DOI: 10.1016/j.neuron.2018.10.031] [Citation(s) in RCA: 289] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 09/14/2018] [Accepted: 10/18/2018] [Indexed: 12/18/2022]
Abstract
Strong evidence implicates the complement pathway as an important contributor to amyloid pathology in Alzheimer's disease (AD); however, the role of complement in tau modulation remains unclear. Here we show that the expression of C3 and C3a receptor (C3aR1) are positively correlated with cognitive decline and Braak staging in human AD brains. Deletion of C3ar1 in PS19 mice results in the rescue of tau pathology and attenuation of neuroinflammation, synaptic deficits, and neurodegeneration. Through RNA sequencing and cell-type-specific transcriptomic analysis, we identify a C3aR-dependent transcription factor network that regulates a reactive glial switch whose inactivation ameliorates disease-associated microglia and neurotoxic astrocyte signatures. Strikingly, this C3aR network includes multiple genes linked to late-onset AD. Mechanistically, we identify STAT3 as a direct target of C3-C3aR signaling that functionally mediates tau pathogenesis. All together our findings demonstrate a crucial role for activation of the C3-C3aR network in mediating neuroinflammation and tau pathology.
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Affiliation(s)
- Alexandra Litvinchuk
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dan B Swartzlander
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Fading Chen
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Allysa Cole
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nicholas E Propson
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Qian Wang
- Department of Genetics and Genomics Science, Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY10029, USA
| | - Bin Zhang
- Department of Genetics and Genomics Science, Mount Sinai Center for Transformative Disease Modeling, Icahn Institute of Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY10029, USA
| | - Zhandong Liu
- Department of Pediatrics-Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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Yeh H, Ikezu T. Transcriptional and Epigenetic Regulation of Microglia in Health and Disease. Trends Mol Med 2018; 25:96-111. [PMID: 30578089 DOI: 10.1016/j.molmed.2018.11.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/30/2022]
Abstract
Microglia are the resident immune cells that maintain brain homeostasis and contribute to neurodegenerative disorders. Recent studies of microglia at transcriptomic and epigenetic levels revealed specific molecular pathways that regulate microglia development, maturation, and reactive states. The transcription factor PU.1 plays a key role in regulating several microglial functions. Environmental factors such as microbiota, early life stress, and maternal immune activation can dysregulate PU.1 and innate immune response. This review discusses the epigenetic regulation of key transcriptional factors in human and murine microglia, highlighting their networks for shaping the microglial function. PU.1 and other microglia-specific transcriptional factors can be further studied to determine their therapeutic applications in neurologic disorders.
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Affiliation(s)
- Hana Yeh
- Graduate Program in Neuroscience, Boston University School of Medicine, Boston, MA 02118, USA; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA.
| | - Tsuneya Ikezu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA.
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Tozaki-Saitoh H, Masuda J, Kawada R, Kojima C, Yoneda S, Masuda T, Inoue K, Tsuda M. Transcription factor MafB contributes to the activation of spinal microglia underlying neuropathic pain development. Glia 2018; 67:729-740. [PMID: 30485546 DOI: 10.1002/glia.23570] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 09/27/2018] [Accepted: 10/25/2018] [Indexed: 11/07/2022]
Abstract
Microglia, which are pathological effectors and amplifiers in the central nervous system, undergo various forms of activation. A well-studied microglial-induced pathological paradigm, spinal microglial activation following peripheral nerve injury (PNI), is a key event for the development of neuropathic pain but the transcription factors contributing to microglial activation are less understood. Herein, we demonstrate that MafB, a dominant transcriptional regulator of mature microglia, is involved in the pathology of a mouse model of neuropathic pain. PNI caused a rapid and marked increase of MafB expression selectively in spinal microglia but not in neurons. We also found that the microRNA mir-152 in the spinal cord which targets MafB expression decreased after PNI, and intrathecal administration of mir-152 mimic suppressed the development of neuropathic pain. Reduced MafB expression using heterozygous Mafb deficient mice and by intrathecal administration of siRNA alleviated the development of PNI-induced mechanical hypersensitivity. Furthermore, we found that intrathecal transfer of Mafb deficient microglia did not induce mechanical hypersensitivity and that conditional Mafb knockout mice did not develop neuropathic pain after PNI. We propose that MafB is a key mediator of the PNI-induced phenotypic alteration of spinal microglia and neuropathic pain development.
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Affiliation(s)
- Hidetoshi Tozaki-Saitoh
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Junya Masuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Ryu Kawada
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Chinami Kojima
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Sosuke Yoneda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Takahiro Masuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
| | - Makoto Tsuda
- Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
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Yang R, Wang H, Wen J, Ma K, Chen D, Chen Z, Huang C. Regulation of microglial process elongation, a featured characteristic of microglial plasticity. Pharmacol Res 2018; 139:286-297. [PMID: 30476531 DOI: 10.1016/j.phrs.2018.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/08/2018] [Accepted: 11/20/2018] [Indexed: 12/16/2022]
Abstract
Microglia, a type of glia within the brain characterized by a ramified morphology, are essential for removing neuronal debris and restricting the expansion of a lesion site. Upon moderate activation, they undergo a transformation in morphology inducing beneficial responses. However, upon strong stimulation, they mediate neuronal damage via production of pro-inflammatory cytokines. The inhibition of this cascade is considered an effective strategy for neuroinflammation-associated disorder therapy. During this pathological activation microglia also undergo a shortening of process length which contributes to the pathogenesis of such disorders. Thus, microglial plasticity should be considered to have two components: one is the production of inflammatory mediators, and the other is the dynamic changes in their processes. The former role has been well-documented in previous studies, while the latter one remains largely unknown. Recently, we and others have reported that the elongation of microglial process is associated with the transformation of microglia from a pro-inflammatory to an anti-inflammatory state, suggesting that the shortening of process length would make the microglia lose their ability to restrict pathological injury, while the elongation of microglial process would help attenuate neuroinflammation. Compared with the traditional anti-neuroinflammatory strategy, stimulating elongation of microglial process not only reduces the production of pro-inflammatory cytokines, but restores the ability of microglia to scan their surrounding environments, thus rendering their homeostasis regulation more effective. In this review, we provide a discussion of the factors that regulate microglial process elongation in vitro and in vivo, aiming to further drive the understanding of microglial process plasticity.
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Affiliation(s)
- Rongrong Yang
- Department of Anesthesiology, Affiliated Hospital of Nantong University, #20 Xisi Road, Nantong 226001, Jiangsu, China.
| | - Hui Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, #19 Qixiu Road, Nantong 226001, Jiangsu, China; Department of Neuroscience & Cell Biology, Rutgers-Robert Wood Johnson Medical School, 675 Hoes lane, Piscataway, 08854, NJ, United States
| | - Jie Wen
- Beijing Allwegene Health, B-607 Wanlin Technology Mansion, 8 Malianwa North Road, Beijing 100094, China
| | - Kai Ma
- Probiotics Australia, 24-30 Blanck Street, Ormeau, QLD, 4208, Australia
| | - Dongjian Chen
- Invasive Technology Department, Nantong First People's Hospital, The Second Affiliated Hospital of Nantong University, #6 North Road Hai'er Xiang, Nantong 226001, Jiangsu, China
| | - Zhuo Chen
- Invasive Technology Department, Nantong First People's Hospital, The Second Affiliated Hospital of Nantong University, #6 North Road Hai'er Xiang, Nantong 226001, Jiangsu, China
| | - Chao Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, #19 Qixiu Road, Nantong 226001, Jiangsu, China.
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Pulido-Salgado M, Vidal-Taboada JM, Barriga GGD, Solà C, Saura J. RNA-Seq transcriptomic profiling of primary murine microglia treated with LPS or LPS + IFNγ. Sci Rep 2018; 8:16096. [PMID: 30382133 PMCID: PMC6208373 DOI: 10.1038/s41598-018-34412-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 10/17/2018] [Indexed: 01/20/2023] Open
Abstract
Microglia, the main resident immune cells in the CNS, are thought to participate in the pathogenesis of various neurological disorders. LPS and LPS + IFNγ are stimuli that are widely used to activate microglia. However, the transcriptomic profiles of microglia treated with LPS and LPS + IFNγ have not been properly compared. Here, we treated murine primary microglial cultures with LPS or LPS + IFNγ for 6 hours and then performed RNA-Sequencing. Gene expression patterns induced by the treatments were obtained by WGCNA and 11 different expression profiles were found, showing differential responses to LPS and LPS + IFNγ in many genes. Interestingly, a subset of genes involved in Parkinson’s, Alzheimer’s and Huntington’s disease were downregulated by both treatments. By DESeq analysis we found differentially upregulated and downregulated genes that confirmed LPS and LPS + IFNγ as inducers of microglial pro-inflammatory responses, but also highlighted their involvement in specific cell functions. In response to LPS, microglia tended to be more proliferative, pro-inflammatory and phagocytic; whereas LPS + IFNγ inhibited genes were involved in pain, cell division and, unexpectedly, production of some inflammatory mediators. In summary, this study provides a detailed description of the transcriptome of LPS- and LPS + IFNγ treated primary microglial cultures. It may be useful to determine whether these in vitro phenotypes resemble microglia in in vivo pathological conditions.
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Affiliation(s)
- Marta Pulido-Salgado
- Department of Biomedical Sciences, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Jose M Vidal-Taboada
- Department of Biomedical Sciences, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain. .,Institute of Neurosciences, University of Barcelona, Barcelona, Spain. .,Peripheral Nervous System, Neuroscience Dept, VHIR- Vall d'Hebron Research Institute, Barcelona, Spain.
| | - Gerardo Garcia-Diaz Barriga
- Department of Biomedical Sciences, Histology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Carme Solà
- Department of Cerebral Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, IDIBAPS, Barcelona, Spain
| | - Josep Saura
- Department of Biomedical Sciences, Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Barcelona, Spain. .,Institute of Neurosciences, University of Barcelona, Barcelona, Spain.
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64
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Lopez‐Atalaya JP, Askew KE, Sierra A, Gomez‐Nicola D. Development and maintenance of the brain's immune toolkit: Microglia and non-parenchymal brain macrophages. Dev Neurobiol 2018; 78:561-579. [PMID: 29030904 PMCID: PMC6001428 DOI: 10.1002/dneu.22545] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/29/2017] [Accepted: 10/06/2017] [Indexed: 01/10/2023]
Abstract
Microglia and non-parenchymal macrophages located in the perivascular space, the meninges and the choroid plexus are independent immune populations that play vital roles in brain development, homeostasis, and tissue healing. Resident macrophages account for a significant proportion of cells in the brain and their density remains stable throughout the lifespan thanks to constant turnover. Microglia develop from yolk sac progenitors, later evolving through intermediate progenitors in a fine-tuned process in which intrinsic factors and external stimuli combine to progressively sculpt their cell type-specific transcriptional profiles. Recent evidence demonstrates that non-parenchymal macrophages are also generated during early embryonic development. In recent years, the development of powerful fate mapping approaches combined with novel genomic and transcriptomic methodologies have greatly expanded our understanding of how brain macrophages develop and acquire specialized functions, and how cell population dynamics are regulated. Here, we review the transcription factors, epigenetic remodeling, and signaling pathways orchestrating the embryonic development of microglia and non-parenchymal macrophages. Next, we describe the dynamics of the macrophage populations of the brain and discuss the role of progenitor cells, to gain a better understanding of their functions in the healthy and diseased brain. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 561-579, 2018.
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Affiliation(s)
- Jose P. Lopez‐Atalaya
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández‐Consejo Superior de Investigaciones Científicas (UMH‐CSIC), Avenida Ramón y Cajal, s/n, Sant Joan d'AlacantSpain
| | - Katharine E. Askew
- Southampton General Hospital, Biological Sciences, University of Southampton, South Lab&Path Block, LD80C, MP840SO166YDSouthamptonUnited Kingdom
| | - Amanda Sierra
- Achucarro Basque Center for NeuroscienceLeioa48940Spain
- Ikerbasque FoundationBilbao48013Spain
- University of the Basque Country EHU/UPVLeioa48940Spain
| | - Diego Gomez‐Nicola
- Southampton General Hospital, Biological Sciences, University of Southampton, South Lab&Path Block, LD80C, MP840SO166YDSouthamptonUnited Kingdom
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65
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Jak kinase 3 signaling in microgliogenesis from the spinal nestin+ progenitors in both development and response to injury. Neuroreport 2018; 28:929-935. [PMID: 28817455 PMCID: PMC5585131 DOI: 10.1097/wnr.0000000000000854] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During spinal cord development, endogenous progenitors expressing nestin can migrate into the target and differentiate into neurons and other glial cells. Microglial cells can also be derived from nestin+ progenitor cells, even in the adult brain. Knockdown of Jak kinase 3 (Jak3) signaling can increase neurogenesis with longer neurite outgrowth in cortical progenitor cells. This study investigated the effect of Jak3 signaling on differentiation from nestin+ progenitor cells using E13.5 spinal progenitor cell cultures. In growth factors-enriched culture, developing neurons could not survive after several days and also a significant proportion of nestin-expressing cells transformed into ameboid Iba1+ microglial cells, which increased exponentially after 5 days. This microgliogenesis was predominantly regulated by Jak3 signaling, which was confirmed by transcription factors responsible for microgliogenesis, and microglial migration and phagocytosis, such as Pu.1, Irf8, and Runx1. Jak3 inhibition also significantly increased the Tuj1+ growing neurites with little microglial activation. These results indicated that neuronal and microglial cell differentiation was regulated primarily by Jak3 signaling and the developing neurons and neurite outgrowth might also be regulated by Jak3-dependent microglial activity.
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66
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Sorrenti V, Contarini G, Sut S, Dall'Acqua S, Confortin F, Pagetta A, Giusti P, Zusso M. Curcumin Prevents Acute Neuroinflammation and Long-Term Memory Impairment Induced by Systemic Lipopolysaccharide in Mice. Front Pharmacol 2018; 9:183. [PMID: 29556196 PMCID: PMC5845393 DOI: 10.3389/fphar.2018.00183] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 02/19/2018] [Indexed: 12/16/2022] Open
Abstract
Systemic lipopolysaccharide (LPS) induces an acute inflammatory response in the central nervous system (CNS) (“neuroinflammation”) characterized by altered functions of microglial cells, the major resident immune cells of the CNS, and an increased inflammatory profile that can result in long-term neuronal cell damage and severe behavioral and cognitive consequences. Curcumin, a natural compound, exerts CNS anti-inflammatory and neuroprotective functions mainly after chronic treatment. However, its effect after acute treatment has not been well investigated. In the present study, we provide evidence that 50 mg/kg of curcumin, orally administered for 2 consecutive days before a single intraperitoneal injection of a high dose of LPS (5 mg/kg) in young adult mice prevents the CNS immune response. Curcumin, able to enter brain tissue in biologically relevant concentrations, reduced acute and transient microglia activation, pro-inflammatory mediator production, and the behavioral symptoms of sickness. In addition, short-term treatment with curcumin, administered at the time of LPS challenge, anticipated the recovery from memory impairments observed 1 month after the inflammatory stimulus, when mice had completely recovered from the acute neuroinflammation. Together, these results suggest that the preventive effect of curcumin in inhibiting the acute effects of neuroinflammation could be of value in reducing the long-term consequences of brain inflammation, including cognitive deficits such as memory dysfunction.
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Affiliation(s)
- Vincenzo Sorrenti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Gabriella Contarini
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Stefania Sut
- Department of Agronomy, Food, Natural Resources, Animals and the Environment, University of Padova, Padua, Italy
| | - Stefano Dall'Acqua
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Francesca Confortin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Andrea Pagetta
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
| | - Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padua, Italy
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67
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A story of birth and death: Insights into the formation and dynamics of the microglial population. Brain Behav Immun 2018; 69:9-17. [PMID: 28341583 DOI: 10.1016/j.bbi.2017.03.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 12/24/2022] Open
Abstract
Microglia are the main resident immunocompetent cells of the brain with key roles in brain development, homeostasis and function. Here we briefly review our current knowledge of the homeostatic mechanisms regulating the composition and turnover of the microglial population under physiological conditions from development to ageing. A greater understanding of these mechanisms may inform understanding of how dysregulation of microglial dynamics could contribute to the pathogenesis and/or progression of neurological disorders.
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68
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Ciernia AV, Careaga M, Ashwood P, LaSalle J. Microglia from offspring of dams with allergic asthma exhibit epigenomic alterations in genes dysregulated in autism. Glia 2018; 66:505-521. [PMID: 29134693 PMCID: PMC5767155 DOI: 10.1002/glia.23261] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/18/2017] [Accepted: 10/25/2017] [Indexed: 12/24/2022]
Abstract
Dysregulation in immune responses during pregnancy increases the risk of a having a child with an autism spectrum disorder (ASD). Asthma is one of the most common chronic diseases among pregnant women, and symptoms often worsen during pregnancy. We recently developed a mouse model of maternal allergic asthma (MAA) that induces changes in sociability, repetitive, and perseverative behaviors in the offspring. Since epigenetic changes help a static genome adapt to the maternal environment, activation of the immune system may epigenetically alter fetal microglia, the brain's resident immune cells. We therefore tested the hypothesis that epigenomic alterations to microglia may be involved in behavioral abnormalities observed in MAA offspring. We used the genome-wide approaches of whole genome bisulfite sequencing to examine DNA methylation and RNA sequencing to examine gene expression in microglia from juvenile MAA offspring. Differentially methylated regions were enriched for immune signaling pathways and important microglial developmental transcription factor binding motifs. Differential expression analysis identified genes involved in controlling microglial sensitivity to the environment and shaping neuronal connections in the developing brain. Differentially expressed genes significantly overlapped genes with altered expression in human ASD cortex, supporting a role for microglia in the pathogenesis of ASD.
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Affiliation(s)
- Annie Vogel Ciernia
- Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616
| | - Milo Careaga
- MIND Institute, 2825 50 Street, Sacramento, CA 95817, University of California, Davis
| | - Paul Ashwood
- MIND Institute, 2825 50 Street, Sacramento, CA 95817, University of California, Davis
| | - Janine LaSalle
- Medical Microbiology and Immunology, University of California, Davis, Davis, CA 95616
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69
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Brown LN, Xing Y, Noble KV, Barth JL, Panganiban CH, Smythe NM, Bridges MC, Zhu J, Lang H. Macrophage-Mediated Glial Cell Elimination in the Postnatal Mouse Cochlea. Front Mol Neurosci 2017; 10:407. [PMID: 29375297 PMCID: PMC5770652 DOI: 10.3389/fnmol.2017.00407] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/23/2017] [Indexed: 12/20/2022] Open
Abstract
Hearing relies on the transmission of auditory information from sensory hair cells (HCs) to the brain through the auditory nerve. This relay of information requires HCs to be innervated by spiral ganglion neurons (SGNs) in an exclusive manner and SGNs to be ensheathed by myelinating and non-myelinating glial cells. In the developing auditory nerve, mistargeted SGN axons are retracted or pruned and excessive cells are cleared in a process referred to as nerve refinement. Whether auditory glial cells are eliminated during auditory nerve refinement is unknown. Using early postnatal mice of either sex, we show that glial cell numbers decrease after the first postnatal week, corresponding temporally with nerve refinement in the developing auditory nerve. Additionally, expression of immune-related genes was upregulated and macrophage numbers increase in a manner coinciding with the reduction of glial cell numbers. Transient depletion of macrophages during early auditory nerve development, using transgenic CD11bDTR/EGFP mice, resulted in the appearance of excessive glial cells. Macrophage depletion caused abnormalities in myelin formation and transient edema of the stria vascularis. Macrophage-depleted mice also showed auditory function impairment that partially recovered in adulthood. These findings demonstrate that macrophages contribute to the regulation of glial cell number during postnatal development of the cochlea and that glial cells play a critical role in hearing onset and auditory nerve maturation.
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Affiliation(s)
- LaShardai N. Brown
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Yazhi Xing
- Department of Otorhinolaryngology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Kenyaria V. Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Jeremy L. Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Clarisse H. Panganiban
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Nancy M. Smythe
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Mary C. Bridges
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Juhong Zhu
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
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70
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Abstract
Microglia and non-parenchymal macrophages in the brain are mononuclear phagocytes that are increasingly recognized to be essential players in the development, homeostasis and diseases of the central nervous system. With the availability of new genetic, molecular and pharmacological tools, considerable advances have been made towards our understanding of the embryonic origins, developmental programmes and functions of these cells. These exciting discoveries, some of which are still controversial, also raise many new questions, which makes brain macrophage biology a fast-growing field at the intersection of neuroscience and immunology. Here, we review the current knowledge of how and where brain macrophages are generated, with a focus on parenchymal microglia. We also discuss their normal functions during development and homeostasis, the disturbance of which may lead to various neurodegenerative and neuropsychiatric diseases.
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71
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Brunet T, King N. The Origin of Animal Multicellularity and Cell Differentiation. Dev Cell 2017; 43:124-140. [PMID: 29065305 PMCID: PMC6089241 DOI: 10.1016/j.devcel.2017.09.016] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/31/2017] [Accepted: 09/19/2017] [Indexed: 12/14/2022]
Abstract
Over 600 million years ago, animals evolved from a unicellular or colonial organism whose cell(s) captured bacteria with a collar complex, a flagellum surrounded by a microvillar collar. Using principles from evolutionary cell biology, we reason that the transition to multicellularity required modification of pre-existing mechanisms for extracellular matrix synthesis and cytokinesis. We discuss two hypotheses for the origin of animal cell types: division of labor from ancient plurifunctional cells and conversion of temporally alternating phenotypes into spatially juxtaposed cell types. Mechanistic studies in diverse animals and their relatives promise to deepen our understanding of animal origins and cell biology.
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Affiliation(s)
- Thibaut Brunet
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Nicole King
- Howard Hughes Medical Institute and the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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72
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Mice deficient in NRROS show abnormal microglial development and neurological disorders. Nat Immunol 2017; 18:633-641. [DOI: 10.1038/ni.3743] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/05/2017] [Indexed: 12/13/2022]
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73
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Quiescence of adult oligodendrocyte precursor cells requires thyroid hormone and hypoxia to activate Runx1. Sci Rep 2017; 7:1019. [PMID: 28432293 PMCID: PMC5430791 DOI: 10.1038/s41598-017-01023-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/23/2017] [Indexed: 12/15/2022] Open
Abstract
The adult mammalian central nervous system (CNS) contains a population of slowly dividing oligodendrocyte precursor cells (OPCs), i.e., adult OPCs, which supply new oligodendrocytes throughout the life of animal. While adult OPCs develop from rapidly dividing perinatal OPCs, the mechanisms underlying their quiescence remain unknown. Here, we show that perinatal rodent OPCs cultured with thyroid hormone (TH) under hypoxia become quiescent and acquire adult OPCs-like characteristics. The cyclin-dependent kinase inhibitor p15/INK4b plays crucial roles in the TH-dependent cell cycle deceleration in OPCs under hypoxia. Klf9 is a direct target of TH-dependent signaling. Under hypoxic conditions, hypoxia-inducible factors mediates runt-related transcription factor 1 activity to induce G1 arrest in OPCs through enhancing TH-dependent p15/INK4b expression. As adult OPCs display phenotypes of adult somatic stem cells in the CNS, the current results shed light on environmental requirements for the quiescence of adult somatic stem cells during their development from actively proliferating stem/progenitor cells.
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74
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Matyash M, Zabiegalov O, Wendt S, Matyash V, Kettenmann H. The adenosine generating enzymes CD39/CD73 control microglial processes ramification in the mouse brain. PLoS One 2017; 12:e0175012. [PMID: 28376099 PMCID: PMC5380357 DOI: 10.1371/journal.pone.0175012] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/20/2017] [Indexed: 02/03/2023] Open
Abstract
Microglial cells invade the brain as amoeboid precursors and acquire a highly ramified morphology in the postnatal brain. Microglia express all essential purinergic elements such as receptors, nucleoside transporters and ecto-enzymes, including CD39 (NTPDase1) and CD73 (5'-nucleotidase), which sequentially degrade extracellular ATP to adenosine. Here, we show that constitutive deletion of CD39 and CD73 or both caused an inhibition of the microglia ramified phenotype in the brain with a reduction in the length of processes, branching frequency and number of intersections with Sholl spheres. In vitro, unlike wild-type microglia, cd39-/- and cd73-/- microglial cells were less complex and did not respond to ATP with the transformation into a more ramified phenotype. In acute brain slices, wild-type microglia retracted approximately 50% of their processes within 15 min after slicing of the brain, and this phenomenon was augmented in cd39-/- mice; moreover, the elongation of microglial processes towards the source of ATP or towards a laser lesion was observed only in wild-type but not in cd39-/- microglia. An elevation of extracellular adenosine 1) by the inhibition of adenosine transport with dipyridamole, 2) by application of exogenous adenosine or 3) by degradation of endogenous ATP/ADP with apyrase enhanced spontaneous and ATP-induced ramification of cd39-/- microglia in acute brain slices and facilitated the transformation of cd39-/- and cd73-/- microglia into a ramified process-bearing phenotype in vitro. These data indicate that under normal physiological conditions, CD39 and CD73 nucleotidases together with equilibrative nucleoside transporter 1 (ENT1) control the fate of extracellular adenosine and thereby the ramification of microglial processes.
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Affiliation(s)
- Marina Matyash
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Oleksandr Zabiegalov
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Stefan Wendt
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Vitali Matyash
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- * E-mail:
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75
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Zusso M, Mercanti G, Belluti F, Di Martino RMC, Pagetta A, Marinelli C, Brun P, Ragazzi E, Lo R, Stifani S, Giusti P, Moro S. Phenolic 1,3-diketones attenuate lipopolysaccharide-induced inflammatory response by an alternative magnesium-mediated mechanism. Br J Pharmacol 2017; 174:1090-1103. [PMID: 28198010 DOI: 10.1111/bph.13746] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Toll-like receptor 4 (TLR4) plays a key role in the induction of inflammatory responses both in peripheral organs and the CNS. Curcumin exerts anti-inflammatory functions by interfering with LPS-induced dimerization of TLR4-myeloid differentiation protein-2 (MD-2) complex and suppressing pro-inflammatory mediator release. However, the inhibitory mechanism of curcumin remains to be defined. EXPERIMENTAL APPROACH Binding of bis-demethoxycurcumin (GG6) and its cyclized pyrazole analogue (GG9), lacking the 1,3-dicarbonyl function, to TLR4-MD-2 was determined using molecular docking simulations. The effects of these compounds on cytokine release and NF-κB activation were examined by ELISA and fluorescence staining in LPS-stimulated primary microglia. Interference with TLR4 dimerization was assessed by immunoprecipitation in Ba/F3 cells. KEY RESULTS Both curcumin analogues bound to the hydrophobic region of the MD-2 pocket. However, only curcumin and GG6, both possessing the 1,3-diketone moiety, inhibited LPS-induced TLR4 dimerization, activation of NF-κB and secretion of pro-inflammatory cytokines in primary microglia. Consistent with the ability of 1,3-diketones to coordinate divalent metal ions, LPS stimulation in a low magnesium environment decreased pro-inflammatory cytokine release and NF-κB p65 nuclear translocation in microglia and decreased TLR4-MD-2 dimerization in Ba/F3 cells. Curcumin and GG6 also significantly reduced cytokine output in contrast to the pyrazole analogue GG9. CONCLUSIONS AND IMPLICATIONS These results indicate that phenolic 1,3-diketones, with a structural motif able to coordinate magnesium ions, can modulate LPS-mediated TLR4-MD-2 signalling. Taken together, these studies identify a previously uncharacterized mechanism involving magnesium, underlying the inflammatory responses to LPS.
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Affiliation(s)
- Morena Zusso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Giulia Mercanti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Federica Belluti
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | | | - Andrea Pagetta
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Carla Marinelli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Paola Brun
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | - Eugenio Ragazzi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Rita Lo
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Stefano Stifani
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Pietro Giusti
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
| | - Stefano Moro
- Molecular Modeling Section, Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy
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76
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Wang JW, Stifani S. Roles of Runx Genes in Nervous System Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 962:103-116. [PMID: 28299654 DOI: 10.1007/978-981-10-3233-2_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Runt-related (Runx) transcription factors play essential roles during development and adult tissue homeostasis and are responsible for several human diseases. They regulate a variety of biological mechanisms in numerous cell lineages. Recent years have seen significant progress in our understanding of the functions performed by Runx proteins in the developing and postnatal mammalian nervous system. In both central and peripheral nervous systems, Runx1 and Runx3 display remarkably specific expression in mostly non-overlapping groups of postmitotic neurons. In the central nervous system, Runx1 is involved in the development of selected motor neurons controlling neural circuits mediating vital functions such as chewing, swallowing, breathing, and locomotion. In the peripheral nervous system, Runx1 and Runx3 play essential roles during the development of sensory neurons involved in circuits mediating pain, itch, thermal sensation and sense of relative position. Runx1 and Runx3 orchestrate complex gene expression programs controlling neuronal subtype specification and axonal connectivity. Runx1 is also important in the olfactory system, where it regulates the progenitor-to-neuron transition in undifferentiated neural progenitor cells in the olfactory epithelium as well as the proliferation and developmental maturation of specific glial cells termed olfactory ensheathing cells. Moreover, upregulated Runx expression is associated with brain injury and disease. Increasing knowledge of the functions of Runx proteins in the developing and postnatal nervous system is therefore expected to improve our understanding of nervous system development, homeostasis and disease.
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Affiliation(s)
- Jae Woong Wang
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A2B4, Canada
| | - Stefano Stifani
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A2B4, Canada.
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Zhang M, Mu H, Shang Z, Kang K, Lv H, Duan L, Li J, Chen X, Teng Y, Jiang Y, Zhang R. Genome-wide pathway-based association analysis identifies risk pathways associated with Parkinson's disease. Neuroscience 2016; 340:398-410. [PMID: 27840232 DOI: 10.1016/j.neuroscience.2016.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 11/03/2016] [Accepted: 11/03/2016] [Indexed: 01/02/2023]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease. It is generally believed that it is influenced by both genetic and environmental factors, but the precise pathogenesis of PD is unknown to date. In this study, we performed a pathway analysis based on genome-wide association study (GWAS) to detect risk pathways of PD in three GWAS datasets. We first mapped all SNP markers to autosomal genes in each GWAS dataset. Then, we evaluated gene risk values using the minimum P-value of the tagSNPs. We took a pathway as a unit to identify the risk pathways based on the cumulative risks of the genes in the pathway. Finally, we combine the analysis results of the three datasets to detect the high risk pathways associated with PD. We found there were five same pathways in the three datasets. Besides, we also found there were five pathways which were shared in two datasets. Most of these pathways are associated with nervoussystem. Five pathways had been reported to be PD-related pathways in the previous literature. Our findings also implied that there was a close association between immune response and PD. Continued investigation of these pathways will further help us explain the pathogenesis of PD.
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Affiliation(s)
- Mingming Zhang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Hongbo Mu
- College of Science, Northeast Forestry University, Harbin, China
| | - Zhenwei Shang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Kai Kang
- Department of Cardiovascular Surgery, The Second Affiliated Hospital of Harbin Medical University, China
| | - Hongchao Lv
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Lian Duan
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Jin Li
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Xinren Chen
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Yanbo Teng
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
| | - Yongshuai Jiang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China.
| | - Ruijie Zhang
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China.
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78
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Cloarec R, Bauer S, Luche H, Buhler E, Pallesi-Pocachard E, Salmi M, Courtens S, Massacrier A, Grenot P, Teissier N, Watrin F, Schaller F, Adle-Biassette H, Gressens P, Malissen M, Stamminger T, Streblow DN, Bruneau N, Szepetowski P. Cytomegalovirus Infection of the Rat Developing Brain In Utero Prominently Targets Immune Cells and Promotes Early Microglial Activation. PLoS One 2016; 11:e0160176. [PMID: 27472761 PMCID: PMC4966896 DOI: 10.1371/journal.pone.0160176] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 07/14/2016] [Indexed: 11/25/2022] Open
Abstract
Background Congenital cytomegalovirus infections are a leading cause of neurodevelopmental disorders in human and represent a major health care and socio-economical burden. In contrast with this medical importance, the pathophysiological events remain poorly known. Murine models of brain cytomegalovirus infection, mostly neonatal, have brought recent insights into the possible pathogenesis, with convergent evidence for the alteration and possible involvement of brain immune cells. Objectives and Methods In order to confirm and expand those findings, particularly concerning the early developmental stages following infection of the fetal brain, we have created a model of in utero cytomegalovirus infection in the developing rat brain. Rat cytomegalovirus was injected intraventricularly at embryonic day 15 (E15) and the brains analyzed at various stages until the first postnatal day, using a combination of gene expression analysis, immunohistochemistry and multicolor flow cytometry experiments. Results Rat cytomegalovirus infection was increasingly seen in various brain areas including the choroid plexi and the ventricular and subventricular areas and was prominently detected in CD45low/int, CD11b+ microglial cells, in CD45high, CD11b+ cells of the myeloid lineage including macrophages, and in CD45+, CD11b– lymphocytes and non-B non-T cells. In parallel, rat cytomegalovirus infection of the developing rat brain rapidly triggered a cascade of pathophysiological events comprising: chemokines upregulation, including CCL2-4, 7 and 12; infiltration by peripheral cells including B-cells and monocytes at E17 and P1, and T-cells at P1; and microglia activation at E17 and P1. Conclusion In line with previous findings in neonatal murine models and in human specimen, our study further suggests that neuroimmune alterations might play critical roles in the early stages following cytomegalovirus infection of the brain in utero. Further studies are now needed to determine which role, whether favorable or detrimental, those putative double-edge swords events actually play.
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Affiliation(s)
- Robin Cloarec
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Sylvian Bauer
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Hervé Luche
- CIPHE (Centre d'Immunophénomique), PHENOMIN, UM2 Aix-Marseille University, Marseille, France
- INSERM US012, Marseille, France
- CNRS UMS3367, Marseille, France
| | - Emmanuelle Buhler
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
- PPGI platform, INMED, Marseille, France
| | - Emilie Pallesi-Pocachard
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
- PBMC platform, INMED, Marseille, France
| | - Manal Salmi
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Sandra Courtens
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Annick Massacrier
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Pierre Grenot
- CIPHE (Centre d'Immunophénomique), PHENOMIN, UM2 Aix-Marseille University, Marseille, France
- CNRS UMS3367, Marseille, France
| | - Natacha Teissier
- INSERM, U1141, Paris, France
- Paris Diderot University, Sorbonne Paris Cité, Paris, France
- PremUP, Paris, France
| | - Françoise Watrin
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
| | - Fabienne Schaller
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
- PPGI platform, INMED, Marseille, France
| | - Homa Adle-Biassette
- INSERM, U1141, Paris, France
- Paris Diderot University, Sorbonne Paris Cité, Paris, France
- PremUP, Paris, France
| | - Pierre Gressens
- INSERM, U1141, Paris, France
- Paris Diderot University, Sorbonne Paris Cité, Paris, France
- PremUP, Paris, France
| | - Marie Malissen
- CIPHE (Centre d'Immunophénomique), PHENOMIN, UM2 Aix-Marseille University, Marseille, France
- INSERM US012, Marseille, France
- CNRS UMS3367, Marseille, France
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Daniel N. Streblow
- Vaccine & Gene Therapy Institute, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Nadine Bruneau
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
- * E-mail: (NB); (PS)
| | - Pierre Szepetowski
- INSERM U901, Marseille, France
- Mediterranean Institute of Neurobiology (INMED), Marseille, France
- UMR_S901, Aix-Marseille University, Marseille, France
- * E-mail: (NB); (PS)
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79
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Tay TL, Savage JC, Hui CW, Bisht K, Tremblay MÈ. Microglia across the lifespan: from origin to function in brain development, plasticity and cognition. J Physiol 2016; 595:1929-1945. [PMID: 27104646 DOI: 10.1113/jp272134] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/15/2016] [Indexed: 12/11/2022] Open
Abstract
Microglia are the only immune cells that permanently reside in the central nervous system (CNS) alongside neurons and other types of glial cells. The past decade has witnessed a revolution in our understanding of their roles during normal physiological conditions. Cutting-edge techniques revealed that these resident immune cells are critical for proper brain development, actively maintain health in the mature brain, and rapidly adapt their function to physiological or pathophysiological needs. In this review, we highlight recent studies on microglial origin (from the embryonic yolk sac) and the factors regulating their differentiation and homeostasis upon brain invasion. Elegant experiments tracking microglia in the CNS allowed studies of their unique roles compared with other types of resident macrophages. Here we review the emerging roles of microglia in brain development, plasticity and cognition, and discuss the implications of the depletion or dysfunction of microglia for our understanding of disease pathogenesis. Immune activation, inflammation and various other conditions resulting in undesirable microglial activity at different stages of life could severely impair learning, memory and other essential cognitive functions. The diversity of microglial phenotypes across the lifespan, between compartments of the CNS, and sexes, as well as their crosstalk with the body and external environment, is also emphasised. Understanding what defines particular microglial phenotypes is of major importance for future development of innovative therapies controlling their effector functions, with consequences for cognition across chronic stress, ageing, neuropsychiatric and neurological diseases.
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Affiliation(s)
- Tuan Leng Tay
- Institute of Neuropathology, University of Freiburg, Germany
| | - Julie C Savage
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Chin Wai Hui
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
| | - Kanchan Bisht
- Axe Neurosciences, Centre de recherche du CHU de Québec, Québec, Canada
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80
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Tay TL, Hagemeyer N, Prinz M. The force awakens: insights into the origin and formation of microglia. Curr Opin Neurobiol 2016; 39:30-7. [PMID: 27107946 DOI: 10.1016/j.conb.2016.04.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 12/12/2022]
Abstract
Microglia are tissue resident macrophages of the central nervous system (CNS) that maintain homeostasis and respond to immune challenges. New genetic fate mapping tools have revealed a yolk sac origin of microglia. Once established in the CNS, microglia persist throughout the lifetime of the organism behind the blood-brain barrier and maintain themselves by self-renewal. Recent studies uncovered a broad spectrum of microglial functions that are influenced by the dynamism of brain formation and neuronal wiring. This review focuses on current findings concerning microglia origin and formation during development and discusses the factors important for microglia survival and function.
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Affiliation(s)
- Tuan Leng Tay
- Institute of Neuropathology, University of Freiburg, Germany
| | - Nora Hagemeyer
- Institute of Neuropathology, University of Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, University of Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, University of Freiburg, Germany.
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81
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Abstract
Microglia are the resident monocytic cells in the central nervous system (CNS), where they constitute the complex tissue structure together with a diverse set of cell-types, including neurons, glial cells, and vasculature. Different from other cells, microglia have distinct features, including not only their origin but functions in the CNS, and serve multiple roles within healthy and diseased CNS tissue. The present review highlights the latest advance in our understanding of the nature of microglia in the CNS, from their origin to both the physiological and pathological roles throughout their whole life.
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Affiliation(s)
- Takahiro Masuda
- Institute
of Neuropathology, University of Freiburg, D-79106 Freiburg, Germany
| | - Marco Prinz
- Institute
of Neuropathology, University of Freiburg, D-79106 Freiburg, Germany
- BIOSS
Centre for Biological Signalling Studies, University of Freiburg, D-79106 Freiburg, Germany
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82
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Crotti A, Ransohoff RM. Microglial Physiology and Pathophysiology: Insights from Genome-wide Transcriptional Profiling. Immunity 2016; 44:505-515. [DOI: 10.1016/j.immuni.2016.02.013] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/06/2016] [Accepted: 02/17/2016] [Indexed: 12/22/2022]
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83
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Masuda T, Tsuda M, Inoue K. Transcriptional regulation in microglia and neuropathic pain. Pain Manag 2016; 6:91-4. [PMID: 26912109 DOI: 10.2217/pmt.15.34] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Takahiro Masuda
- Department of Molecular & System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.,Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.,Institute of Neuropathology, University of Freiburg, Freiburg 79106, Germany.,Core Research for Evolution Science & Technology, Japan Science & Technology Agency, Tokyo 102-0076, Japan
| | - Makoto Tsuda
- Department of Molecular & System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.,Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Kazuhide Inoue
- Department of Molecular & System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.,Core Research for Evolution Science & Technology, Japan Science & Technology Agency, Tokyo 102-0076, Japan
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84
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Transcriptional regulation of mouse hypoglossal motor neuron somatotopic map formation. Brain Struct Funct 2015; 221:4187-4202. [DOI: 10.1007/s00429-015-1160-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/24/2015] [Indexed: 11/25/2022]
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85
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High Gestational Folic Acid Supplementation Alters Expression of Imprinted and Candidate Autism Susceptibility Genes in a sex-Specific Manner in Mouse Offspring. J Mol Neurosci 2015; 58:277-86. [PMID: 26547318 DOI: 10.1007/s12031-015-0673-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/30/2015] [Indexed: 02/07/2023]
Abstract
Maternal nutrients play critical roles in modulating epigenetic events and exert long-term influences on the progeny's health. Folic acid (FA) supplementation during pregnancy has decreased the incidence of neural tube defects in newborns, but the influence of high doses of maternal FA supplementation on infants' brain development is unclear. The present study was aimed at investigating the effects of a high dose of gestational FA on the expression of genes in the cerebral hemispheres (CHs) of 1-day-old pups. One week prior to mating and throughout the entire period of gestation, female C57BL/6J mice were fed a diet, containing FA at either 2 mg/kg (control diet (CD)) or 20 mg/kg (high maternal folic acid (HMFA)). At postnatal day 1, pups from different dams were sacrificed and CH tissues were collected. Quantitative RT-PCR and Western blot analysis confirmed sex-specific alterations in the expression of several genes that modulate various cellular functions (P < 0.05) in pups from the HMFA group. Genomic DNA methylation analysis showed no difference in the level of overall methylation in pups from the HMFA group. These findings demonstrate that HMFA supplementation alters offsprings' CH gene expression in a sex-specific manner. These changes may influence infants' brain development.
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86
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Voon DCC, Hor YT, Ito Y. The RUNX complex: reaching beyond haematopoiesis into immunity. Immunology 2015; 146:523-36. [PMID: 26399680 DOI: 10.1111/imm.12535] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/13/2015] [Accepted: 07/15/2015] [Indexed: 12/24/2022] Open
Abstract
Among their diverse roles as transcriptional regulators during development and cell fate specification, the RUNX transcription factors are best known for the parts they play in haematopoiesis. RUNX proteins are expressed throughout all haematopoietic lineages, being necessary for the emergence of the first haematopoietic stem cells to their terminal differentiation. Although much progress has been made since their discoveries almost two decades ago, current appreciation of RUNX in haematopoiesis is largely grounded in their lineage-specifying roles. In contrast, the importance of RUNX to immunity has been mostly obscured for historic, technical and conceptual reasons. However, this paradigm is likely to shift over time, as a primary purpose of haematopoiesis is to resource the immune system. Furthermore, recent evidence suggests a role for RUNX in the innate immunity of non-haematopoietic cells. This review takes a haematopoiesis-centric approach to collate what is known of RUNX's contribution to the overall mammalian immune system and discuss their growing prominence in areas such as autoimmunity, inflammatory diseases and mucosal immunity.
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Affiliation(s)
- Dominic Chih-Cheng Voon
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan.,Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
| | | | - Yoshiaki Ito
- Cancer Biology Programme, Cancer Science Institute of Singapore, Singapore
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87
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Wieghofer P, Prinz M. Genetic manipulation of microglia during brain development and disease. Biochim Biophys Acta Mol Basis Dis 2015; 1862:299-309. [PMID: 26432479 DOI: 10.1016/j.bbadis.2015.09.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/24/2015] [Accepted: 09/25/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Peter Wieghofer
- Institute of Neuropathology, University of Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, University of Freiburg, Germany; BIOSS Centre for Biological Signaling Studies, University of Freiburg, Germany.
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88
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Logan TT, Rusnak M, Symes AJ. Runx1 promotes proliferation and neuronal differentiation in adult mouse neurosphere cultures. Stem Cell Res 2015; 15:554-564. [PMID: 26473321 DOI: 10.1016/j.scr.2015.09.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/21/2015] [Accepted: 09/26/2015] [Indexed: 02/06/2023] Open
Abstract
Traumatic brain injury alters the signaling environment of the adult neurogenic niche and may activate unique proliferative cell populations that contribute to the post-injury neurogenic response. Runx1 is not normally expressed by adult neural stem or progenitor cells (NSPCs) but is induced in a subpopulation of putative NSPCs after brain injury in adult mice. In order to investigate the role of Runx1 in NSPCs, we established neurosphere cultures of adult mouse subventricular zone NSPCs. We show that Runx1 is basally expressed in neurosphere culture. Removal of the mitogen bFGF or addition of 1% FBS decreased Runx1 expression. Inhibition of endogenous Runx1 activity with either Ro5-3335 or shRNA-mediated Runx1 knockdown inhibited NSPC proliferation without affecting differentiation. Lentiviral mediated over-expression of Runx1 in neurospheres caused a significant change in cell morphology without reducing proliferation. Runx1-overexpressing neurospheres changed from floating spheres to adherent colonies or individual unipolar or bipolar cells. Flow cytometry analysis indicated that Runx1 over-expression produced a significant increase in expression of the neuronal marker TuJ1 and a minor increase in the astrocytic marker S100β. Thus, Runx1 expression drove adult NSPC differentiation, predominantly toward a neuronal lineage. These data suggest that Runx1 could be manipulated after injury to promote neuronal differentiation to facilitate repair of the CNS.
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Affiliation(s)
- T T Logan
- Department of Pharmacology and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - M Rusnak
- Department of Pharmacology and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - A J Symes
- Department of Pharmacology and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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89
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Shemer A, Erny D, Jung S, Prinz M. Microglia Plasticity During Health and Disease: An Immunological Perspective. Trends Immunol 2015; 36:614-624. [DOI: 10.1016/j.it.2015.08.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/02/2015] [Accepted: 08/12/2015] [Indexed: 12/23/2022]
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90
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Wehrspaun CC, Haerty W, Ponting CP. Microglia recapitulate a hematopoietic master regulator network in the aging human frontal cortex. Neurobiol Aging 2015; 36:2443.e9-2443.e20. [PMID: 26002684 PMCID: PMC4503803 DOI: 10.1016/j.neurobiolaging.2015.04.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/18/2015] [Accepted: 04/17/2015] [Indexed: 12/11/2022]
Abstract
Microglia form the immune system of the brain. Previous studies in cell cultures and animal models suggest altered activation states and cellular senescence in the aged brain. Instead, we analyzed 3 transcriptome data sets from the postmortem frontal cortex of 381 control individuals to show that microglia gene markers assemble into a transcriptional module in a gene coexpression network. These markers predominantly represented M1 and M1/M2b activation phenotypes. Expression of genes in this module generally declines over the adult life span. This decrease was more pronounced in microglia surface receptors for microglia and/or neuron crosstalk than in markers for activation state phenotypes. In addition to these receptors for exogenous signals, microglia are controlled by brain-expressed regulatory factors. We identified a subnetwork of transcription factors, including RUNX1, IRF8, PU.1, and TAL1, which are master regulators (MRs) for the age-dependent microglia module. The causal contributions of these MRs on the microglia module were verified using publicly available ChIP-Seq data. Interactions of these key MRs were preserved in a protein-protein interaction network. Importantly, these MRs appear to be essential for regulating microglia homeostasis in the adult human frontal cortex in addition to their crucial roles in hematopoiesis and myeloid cell-fate decisions during embryogenesis.
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Affiliation(s)
- Claudia C Wehrspaun
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK; Section on Neuropathology, Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, IRP, NIMH, NIH, Bethesda, MD, USA.
| | - Wilfried Haerty
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK; Department of Physiology, Anatomy and Genetics, MRC Functional Genomics Unit, University of Oxford, UK
| | - Chris P Ponting
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK; Department of Physiology, Anatomy and Genetics, MRC Functional Genomics Unit, University of Oxford, UK
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91
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Tsuda M. Microglia in the spinal cord and neuropathic pain. J Diabetes Investig 2015; 7:17-26. [PMID: 26813032 PMCID: PMC4718109 DOI: 10.1111/jdi.12379] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 05/13/2015] [Accepted: 05/16/2015] [Indexed: 12/13/2022] Open
Abstract
In contrast to physiological pain, pathological pain is not dependent on the presence of tissue‐damaging stimuli. One type of pathological pain – neuropathic pain – is often a consequence of nerve injury or of diseases such as diabetes. Neuropathic pain can be agonizing, can persist over long periods and is often resistant to known painkillers. A growing body of evidence shows that many pathological processes within the central nervous system are mediated by complex interactions between neurons and glial cells. In the case of painful peripheral neuropathy, spinal microglia react and undergo a series of changes that directly influence the establishment of neuropathic pain states. After nerve damage, purinergic P2X4 receptors (non‐selective cation channels activated by extracellular adenosine triphosphate) are upregulated in spinal microglia in a manner that depends on the transcription factors interferon regulatory factor 8 and 5, both of which are expressed in microglia after peripheral nerve injury. P2X4 receptor expression on the cell surface of microglia is also regulated at the post‐translational level by signaling from CC chemokine receptor chemotactic cytokine receptor 2. Furthermore, spinal microglia in response to extracellular stimuli results in signal transduction through intracellular signaling cascades, such as mitogen‐activated protein kinases, p38 and extracellular signal‐regulated protein kinase. Importantly, inhibiting the function or expression of these microglial molecules suppresses the aberrant excitability of dorsal horn neurons and neuropathic pain. These findings show that spinal microglia are a central player in mechanisms for neuropathic pain, and might be a potential target for treating the chronic pain state.
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Affiliation(s)
- Makoto Tsuda
- Department of Life Innovation Graduate School of Pharmaceutical Sciences Kyushu University Fukuoka Japan
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92
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Abstract
This review summarizes and organizes the literature concerning the effects of microglia on neurogenesis, particularly focusing on the subgranular zone (SGZ) of the hippocampus and subventricular zone (SVZ) of the lateral ventricles, in which the neurogenic potential is progressively restricted during the life of the organism. A comparison of microglial roles in neurogenesis in these two regions indicates that microglia regulate neurogenesis in a temporally and spatially specific manner. Microglia may also sense signals from the surrounding environment and have regulatory effects on neurogenesis. We speculate microglia function as a hub for the information obtained from the inner and outer brain regions for regulating neurogenesis.
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Affiliation(s)
- Kaoru Sato
- Division of Pharmacology, Laboratory of Neuropharmacology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-Ku, Tokyo, 158-8501, Japan
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93
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KhorshidAhmad T, Acosta C, Cortes C, Lakowski TM, Gangadaran S, Namaka M. Transcriptional Regulation of Brain-Derived Neurotrophic Factor (BDNF) by Methyl CpG Binding Protein 2 (MeCP2): a Novel Mechanism for Re-Myelination and/or Myelin Repair Involved in the Treatment of Multiple Sclerosis (MS). Mol Neurobiol 2015; 53:1092-1107. [PMID: 25579386 DOI: 10.1007/s12035-014-9074-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/29/2014] [Indexed: 12/13/2022]
Abstract
Multiple sclerosis (MS) is a chronic progressive, neurological disease characterized by the targeted immune system-mediated destruction of central nervous system (CNS) myelin. Autoreactive CD4+ T helper cells have a key role in orchestrating MS-induced myelin damage. Once activated, circulating Th1-cells secrete a variety of inflammatory cytokines that foster the breakdown of blood-brain barrier (BBB) eventually infiltrating into the CNS. Inside the CNS, they become reactivated upon exposure to the myelin structural proteins and continue to produce inflammatory cytokines such as tumor necrosis factor α (TNFα) that leads to direct activation of antibodies and macrophages that are involved in the phagocytosis of myelin. Proliferating oligodendrocyte precursors (OPs) migrating to the lesion sites are capable of acute remyelination but unable to completely repair or restore the immune system-mediated myelin damage. This results in various permanent clinical neurological disabilities such as cognitive dysfunction, fatigue, bowel/bladder abnormalities, and neuropathic pain. At present, there is no cure for MS. Recent remyelination and/or myelin repair strategies have focused on the role of the neurotrophin brain-derived neurotrophic factor (BDNF) and its upstream transcriptional repressor methyl CpG binding protein (MeCP2). Research in the field of epigenetic therapeutics involving histone deacetylase (HDAC) inhibitors and lysine acetyl transferase (KAT) inhibitors is being explored to repress the detrimental effects of MeCP2. This review will address the role of MeCP2 and BDNF in remyelination and/or myelin repair and the potential of HDAC and KAT inhibitors as novel therapeutic interventions for MS.
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Affiliation(s)
- Tina KhorshidAhmad
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Crystal Acosta
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Claudia Cortes
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Ted M Lakowski
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Surendiran Gangadaran
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada.,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada
| | - Michael Namaka
- College of Pharmacy, University of Manitoba, 750 McDermot Avenue, Winnipeg, R3E 0T5, Manitoba, Canada. .,Manitoba Multiple Sclerosis Research Network Organization (MMSRNO), Winnipeg, Canada. .,College of Medicine, University of Manitoba, Winnipeg, Canada. .,School of Medical Rehabilitation, College of Medicine, University of Manitoba, Winnipeg, Canada.
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94
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Satoh JI, Asahina N, Kitano S, Kino Y. A Comprehensive Profile of ChIP-Seq-Based PU.1/Spi1 Target Genes in Microglia. GENE REGULATION AND SYSTEMS BIOLOGY 2014; 8:127-39. [PMID: 25574134 PMCID: PMC4262374 DOI: 10.4137/grsb.s19711] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/02/2014] [Accepted: 11/10/2014] [Indexed: 01/08/2023]
Abstract
Microglia are resident mononuclear phagocytes that play a principal role in the maintenance of normal tissue homeostasis in the central nervous system (CNS). Microglia, rapidly activated in response to proinflammatory stimuli, are accumulated in brain lesions of neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. The E26 transformation-specific (ETS) family transcription factor PU.1/Spi1 acts as a master regulator of myeloid and lymphoid development. PU.1-deficient mice show a complete loss of microglia, indicating that PU.1 plays a pivotal role in microgliogenesis. However, the comprehensive profile of PU.1/Spi1 target genes in microglia remains unknown. By analyzing a chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) dataset numbered SRP036026 with the Strand NGS program, we identified 5,264 Spi1 target protein-coding genes in BV2 mouse microglial cells. They included Spi1, Irf8, Runx1, Csf1r, Csf1, Il34, Aif1 (Iba1), Cx3cr1, Trem2, and Tyrobp. By motif analysis, we found that the PU-box consensus sequences were accumulated in the genomic regions surrounding ChIP-Seq peaks. By using pathway analysis tools of bioinformatics, we found that ChIP-Seq-based Spi1 target genes show a significant relationship with diverse pathways essential for normal function of monocytes/macrophages, such as endocytosis, Fc receptor-mediated phagocytosis, and lysosomal degradation. These results suggest that PU.1/Spi1 plays a crucial role in regulation of the genes relevant to specialized functions of microglia. Therefore, aberrant regulation of PU.1 target genes might contribute to the development of neurodegenerative diseases with accumulation of activated microglia.
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Affiliation(s)
- Jun-Ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
| | - Naohiro Asahina
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
| | - Shouta Kitano
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
| | - Yoshihiro Kino
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
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95
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Nikodemova M, Kimyon RS, De I, Small AL, Collier LS, Watters JJ. Microglial numbers attain adult levels after undergoing a rapid decrease in cell number in the third postnatal week. J Neuroimmunol 2014; 278:280-8. [PMID: 25468773 DOI: 10.1016/j.jneuroim.2014.11.018] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 12/23/2022]
Abstract
During postnatal development, microglia, CNS resident innate immune cells, are essential for synaptic pruning, neuronal apoptosis and remodeling. During this period microglia undergo morphological and phenotypic transformations; however, little is known about how microglial number and density is regulated during postnatal CNS development. We found that after an initial increase during the first 14 postnatal days, microglial numbers in mouse brain began declining in the third postnatal week and were reduced by 50% by 6weeks of age; these "adult" levels were maintained until at least 9months of age. Microglial CD11b levels increased, whereas CD45 and ER-MP58 declined between P10 and adulthood, consistent with a maturing microglial phenotype. Our data indicate that both increased microglial apoptosis and a decreased proliferative capacity contribute to the developmental reduction in microglial numbers. We found no correlation between developmental reductions in microglial numbers and brain mRNA levels of Cd200, Cx3Cl1, M-Csf or Il-34. We tested the ability of M-Csf-overexpression, a key growth factor promoting microglial proliferation and survival, to prevent microglial loss in the third postnatal week. Mice overexpressing M-Csf in astrocytes had higher numbers of microglia at all ages tested. However, the developmental decline in microglial numbers still occurred, suggesting that chronically elevated M-CSF is unable to overcome the developmental decrease in microglial numbers. Whereas the identity of the factor(s) regulating microglial number and density during development remains to be determined, it is likely that microglia respond to a "maturation" signal since the reduction in microglial numbers coincides with CNS maturation.
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Affiliation(s)
- Maria Nikodemova
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Rebecca S Kimyon
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Ishani De
- School of Pharmacy and Molecular and Cellular Pharmacology Graduate Program, University of Wisconsin-Madison, United States
| | - Alissa L Small
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Lara S Collier
- School of Pharmacy and Molecular and Cellular Pharmacology Graduate Program, University of Wisconsin-Madison, United States
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States.
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96
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Sierra A, Navascués J, Cuadros MA, Calvente R, Martín-Oliva D, Ferrer-Martín RM, Martín-Estebané M, Carrasco MC, Marín-Teva JL. Expression of inducible nitric oxide synthase (iNOS) in microglia of the developing quail retina. PLoS One 2014; 9:e106048. [PMID: 25170849 PMCID: PMC4149512 DOI: 10.1371/journal.pone.0106048] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/28/2014] [Indexed: 12/17/2022] Open
Abstract
Inducible nitric oxide synthase (iNOS), which produce large amounts of nitric oxide (NO), is induced in macrophages and microglia in response to inflammatory mediators such as LPS and cytokines. Although iNOS is mainly expressed by microglia that become activated in different pathological and experimental situations, it was recently reported that undifferentiated amoeboid microglia can also express iNOS during normal development. The aim of this study was to investigate the pattern of iNOS expression in microglial cells during normal development and after their activation with LPS by using the quail retina as model. iNOS expression was analyzed by iNOS immunolabeling, western-blot, and RT-PCR. NO production was determined by using DAR-4M AM, a reliable fluorescent indicator of subcellular NO production by iNOS. Embryonic, postnatal, and adult in situ quail retinas were used to analyze the pattern of iNOS expression in microglial cells during normal development. iNOS expression and NO production in LPS-treated microglial cells were investigated by an in vitro approach based on organotypic cultures of E8 retinas, in which microglial cell behavior is similar to that of the in situ retina, as previously demonstrated in our laboratory. We show here that amoeboid microglia in the quail retina express iNOS during normal development. This expression is stronger in microglial cells migrating tangentially in the vitreal part of the retina and is downregulated, albeit maintained, when microglia differentiate and become ramified. LPS treatment of retina explants also induces changes in the morphology of amoeboid microglia compatible with their activation, increasing their lysosomal compartment and upregulating iNOS expression with a concomitant production of NO. Taken together, our findings demonstrate that immature microglial cells express iNOS during normal development, suggesting a certain degree of activation. Furthermore, LPS treatment induces overactivation of amoeboid microglia, resulting in a significant iNOS upregulation.
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Affiliation(s)
- Ana Sierra
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Julio Navascués
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Miguel A. Cuadros
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Ruth Calvente
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - David Martín-Oliva
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Rosa M. Ferrer-Martín
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - María Martín-Estebané
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - María-Carmen Carrasco
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - José L. Marín-Teva
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
- * E-mail:
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97
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Transcription factors FOXG1 and Groucho/TLE promote glioblastoma growth. Nat Commun 2014; 4:2956. [PMID: 24356439 PMCID: PMC3984242 DOI: 10.1038/ncomms3956] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/18/2013] [Indexed: 01/24/2023] Open
Abstract
Glioblastoma (GBM) is the most common and deadly malignant brain cancer, with a median survival of less than two years. GBM displays a cellular complexity that includes brain tumour-initiating cells (BTICs), which are considered as potential key targets for GBM therapies. Here we show that the transcription factors FOXG1 and Groucho/TLE are expressed in poorly differentiated astroglial cells in human GBM specimens and in primary cultures of GBM-derived BTICs, where they form a complex. FOXG1 knockdown in BTICs causes downregulation of neural stem/progenitor and proliferation markers, increased replicative senescence, upregulation of astroglial differentiation genes, and decreased BTIC-initiated tumour growth upon intracranial transplantation into host mice. These effects are phenocopied by Groucho/TLE knockdown or dominant-inhibition of the FOXG1:Groucho/TLE complex. These results provide evidence that transcriptional programs regulated by FOXG1 and Groucho/TLE are important for BTIC-initiated brain tumour growth, implicating FOXG1 and Groucho/TLE in GBM tumorigenesis.
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98
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Microglia and brain macrophages in the molecular age: from origin to neuropsychiatric disease. Nat Rev Neurosci 2014; 15:300-12. [PMID: 24713688 DOI: 10.1038/nrn3722] [Citation(s) in RCA: 931] [Impact Index Per Article: 93.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mononuclear phagocytic cells in the CNS used to be defined according to their anatomical location and surface marker expression. Recently, this concept has been challenged by the results of developmental and gene expression profiling studies that have used novel molecular biological tools to unravel the origin of microglia and to define their role as specialized tissue macrophages with long lifespans. Here, we describe how these results have redefined microglia and helped us to understand how different myeloid cell populations operate in the CNS based on their cell-specific gene expression signatures, distinct ontogeny and differential functions. Moreover, we describe the vulnerability of microglia to dysfunction and propose that myelomonocytic cells might be used in the treatment of neurological and psychiatric disorders that are characterized by primary or secondary 'microgliopathy'.
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99
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Murthy M, Bocking S, Verginelli F, Stifani S. Transcription factor Runx1 inhibits proliferation and promotes developmental maturation in a selected population of inner olfactory nerve layer olfactory ensheathing cells. Gene 2014; 540:191-200. [PMID: 24582971 DOI: 10.1016/j.gene.2014.02.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 01/30/2014] [Accepted: 02/21/2014] [Indexed: 11/18/2022]
Abstract
The olfactory system undergoes persistent regeneration throughout life. Olfactory ensheathing cells (OECs) are a specialized class of glia found exclusively in the olfactory system. OECs wrap olfactory sensory neuron axons and support their growth from the olfactory epithelium, and targeting to the olfactory bulb, during development and life-long regeneration. Because of this function and their ability to cross the boundary between central and peripheral nervous systems, OECs are attractive candidates for cell-based regenerative therapies to promote axonal repair in the injured nervous system. OECs are a molecularly, topologically and functionally heterogeneous group of cells and the mechanisms underlying the development and function of specific OEC subpopulations are poorly defined. This situation has affected the outcome and interpretation of OEC-based regenerative strategies. Here we show that the transcription factor Runx1 is selectively expressed in OECs of the inner olfactory nerve layer of the mouse olfactory bulb and in their precursors in the OEC migratory mass. Furthermore, we provide evidence that in vivo knockdown of mouse Runx1 increases the proliferation of the OECs in which Runx1 is expressed. Conversely, Runx1 overexpression in primary cultures of OECs reduces cell proliferation in vitro. Decreased Runx1 activity also leads to an increase in Runx1-expressing OEC precursors, with a parallel decrease in the number of more developmentally mature OECs. These results identify Runx1 as a useful new marker of a distinct OEC subpopulation and suggest that Runx1 is important for the development of this group of OECs. These observations provide an avenue for further exploration into the molecular mechanisms underlying the development and function of specific OEC subpopulations.
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Affiliation(s)
- Manjari Murthy
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Sarah Bocking
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Federica Verginelli
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Stefano Stifani
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
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100
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Abstract
Proper development and function of the mammalian central nervous system (CNS) depend critically on the activity of parenchymal sentinels referred to as microglia. Although microglia were first described as ramified brain-resident phagocytes, research conducted over the past century has expanded considerably upon this narrow view and ascribed many functions to these dynamic CNS inhabitants. Microglia are now considered among the most versatile cells in the body, possessing the capacity to morphologically and functionally adapt to their ever-changing surroundings. Even in a resting state, the processes of microglia are highly dynamic and perpetually scan the CNS. Microglia are in fact vital participants in CNS homeostasis, and dysregulation of these sentinels can give rise to neurological disease. In this review, we discuss the exciting developments in our understanding of microglial biology, from their developmental origin to their participation in CNS homeostasis and pathophysiological states such as neuropsychiatric disorders, neurodegeneration, sterile injury responses, and infectious diseases. We also delve into the world of microglial dynamics recently uncovered using real-time imaging techniques.
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Affiliation(s)
- Debasis Nayak
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892;
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