51
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Hamilton L, Astell KR, Velikova G, Sieger D. A Zebrafish Live Imaging Model Reveals Differential Responses of Microglia Toward Glioblastoma Cells In Vivo. Zebrafish 2016; 13:523-534. [PMID: 27779463 PMCID: PMC5124743 DOI: 10.1089/zeb.2016.1339] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glioblastoma multiforme is the most common and deadliest form of brain cancer. Glioblastomas are infiltrated by a high number of microglia, which promote tumor growth and surrounding tissue invasion. However, it is unclear how microglia and glioma cells physically interact and if there are differences, depending on glioma cell type. Hence, we have developed a novel live imaging assay to study microglia-glioma interactions in vivo in the zebrafish brain. We transplanted well-established human glioblastoma cell lines, U87 and U251, into transgenic zebrafish lines with labelled macrophages/microglia. Our confocal live imaging results show distinct interactions between microglia and U87, as well as U251 glioblastoma cells that differ in number and nature. Importantly these interactions do not appear to be antitumoral as zebrafish microglia do not engulf and phagocytose the human glioblastoma cells. Finally, xenotransplants into the irf8-/- zebrafish mutant that lacks microglia, as well as pharmacological inhibition of the CSF-1 receptor (CSF-1R) on microglia, confirm a prominent role for zebrafish microglia in promoting human glioblastoma cell growth. This new model will be an important tool for drug screening and the development of future immunotherapeutics targeting microglia within glioma.
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Affiliation(s)
- Lloyd Hamilton
- Centre for Neuroregeneration, University of Edinburgh , Edinburgh, United Kingdom
| | - Katy R Astell
- Centre for Neuroregeneration, University of Edinburgh , Edinburgh, United Kingdom
| | - Gergana Velikova
- Centre for Neuroregeneration, University of Edinburgh , Edinburgh, United Kingdom
| | - Dirk Sieger
- Centre for Neuroregeneration, University of Edinburgh , Edinburgh, United Kingdom
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52
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Astell KR, Sieger D. Investigating microglia-brain tumor cell interactions in vivo in the larval zebrafish brain. Methods Cell Biol 2016; 138:593-626. [PMID: 28129859 DOI: 10.1016/bs.mcb.2016.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Glioblastoma is the most frequent and aggressive primary malignant brain tumor. Gliomas exhibit high genetic diversity in addition to complex and variable clinical features. Glioblastoma tumors are highly resistant to multimodal therapies and there is significant patient mortality within the first two years after prognosis. At present clinical treatments are palliative, not curative. Glioblastomas contain a high number of microglia and infiltrating macrophages, which are positively correlated with glioma grade and invasiveness. Microglia are the resident macrophages of the central nervous system. These cells constantly scan the brain and react promptly to any abnormality, removing detrimental factors and safeguarding the central nervous system against further damage. Microglia and macrophages that have colonized the glioblastoma display protumoral functions and promote tumor growth. The optically transparent zebrafish larva facilitates imaging of fluorescently labeled cells at high spatial and temporal resolution in vivo. It is therefore an excellent model to investigate microglia-glioma cell interactions at the early stages of tumor development. Here we provide several methods that can be used to study the early stages of microglia-glioma cell interactions in the zebrafish. We present a technique for the xenotransplantation of mammalian oncogenic cells into the zebrafish brain and provide advice for image capture and analysis.
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Affiliation(s)
- K R Astell
- University of Edinburgh, Edinburgh, United Kingdom
| | - D Sieger
- University of Edinburgh, Edinburgh, United Kingdom
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53
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Oosterhof N, Holtman IR, Kuil LE, van der Linde HC, Boddeke EWGM, Eggen BJL, van Ham TJ. Identification of a conserved and acute neurodegeneration-specific microglial transcriptome in the zebrafish. Glia 2016; 65:138-149. [PMID: 27757989 PMCID: PMC5215681 DOI: 10.1002/glia.23083] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/21/2016] [Accepted: 09/28/2016] [Indexed: 12/29/2022]
Abstract
Microglia are brain resident macrophages important for brain development, connectivity, homeostasis and disease. However, it is still largely unclear how microglia functions and their identity are regulated at the molecular level. Although recent transcriptomic studies have identified genes specifically expressed in microglia, the function of most of these genes in microglia is still unknown. Here, we performed RNA sequencing on microglia acutely isolated from healthy and neurodegenerative zebrafish brains. We found that a large fraction of the mouse microglial signature is conserved in the zebrafish, corroborating the use of zebrafish to help understand microglial genetics in mammals in addition to studying basic microglia biology. Second, our transcriptome analysis of microglia following neuronal ablation suggested primarily a proliferative response of microglia, which we confirmed by immunohistochemistry and in vivo imaging. Together with the recent improvements in genome editing technology in zebrafish, these data offer opportunities to facilitate functional genetic research on microglia in vivo in the healthy as well as in the diseased brain. GLIA 2016;65:138–149
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Affiliation(s)
- Nynke Oosterhof
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Inge R Holtman
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Laura E Kuil
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Herma C van der Linde
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
| | - Erik W G M Boddeke
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Bart J L Eggen
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 971 3, AV, Groningen, The Netherlands
| | - Tjakko J van Ham
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Wytemaweg 80, CN, 3015, The Netherlands
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54
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Weber T, Namikawa K, Winter B, Müller-Brown K, Kühn R, Wurst W, Köster RW. Caspase-mediated apoptosis induction in zebrafish cerebellar Purkinje neurons. Development 2016; 143:4279-4287. [PMID: 27729409 DOI: 10.1242/dev.122721] [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: 01/28/2015] [Accepted: 09/30/2016] [Indexed: 01/11/2023]
Abstract
The zebrafish is a well-established model organism in which to study in vivo mechanisms of cell communication, differentiation and function. Existing cell ablation methods are either invasive or they rely on the cellular expression of prokaryotic enzymes and the use of antibiotic drugs as cell death-inducing compounds. We have recently established a novel inducible genetic cell ablation system based on tamoxifen-inducible Caspase 8 activity, thereby exploiting mechanisms of cell death intrinsic to most cell types. Here, we prove its suitability in vivo by monitoring the ablation of cerebellar Purkinje cells (PCs) in transgenic zebrafish that co-express the inducible caspase and a fluorescent reporter. Incubation of larvae in tamoxifen for 8 h activated endogenous Caspase 3 and cell death, whereas incubation for 16 h led to the near-complete loss of PCs by apoptosis. We observed synchronous cell death autonomous to the PC population and phagocytosing microglia in the cerebellum, reminiscent of developmental apoptosis in the forebrain. Thus, induction of apoptosis through targeted activation of caspase by tamoxifen (ATTACTM) further expands the repertoire of genetic tools for conditional interrogation of cellular functions.
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Affiliation(s)
- Thomas Weber
- TU Braunschweig, Zoological Institute, Cellular and Molecular Neurobiology, Spielmannstr. 7, Braunschweig 38106, Germany.,Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Kazuhiko Namikawa
- TU Braunschweig, Zoological Institute, Cellular and Molecular Neurobiology, Spielmannstr. 7, Braunschweig 38106, Germany
| | - Barbara Winter
- TU Braunschweig, Zoological Institute, Cellular and Molecular Neurobiology, Spielmannstr. 7, Braunschweig 38106, Germany
| | - Karina Müller-Brown
- TU Braunschweig, Zoological Institute, Cellular and Molecular Neurobiology, Spielmannstr. 7, Braunschweig 38106, Germany
| | - Ralf Kühn
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Wolfgang Wurst
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Developmental Genetics, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen e. V. (DZNE), Standort München, Feodor-Lynen-Str. 17, München 81377, Germany.,Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Str. 17, München 81377, Germany.,Technische Universität München-Weihenstephan, Lehrstuhl für Entwicklungsgenetik, c/o Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Reinhard W Köster
- TU Braunschweig, Zoological Institute, Cellular and Molecular Neurobiology, Spielmannstr. 7, Braunschweig 38106, Germany
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55
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Xu J, Wang T, Wu Y, Jin W, Wen Z. Microglia Colonization of Developing Zebrafish Midbrain Is Promoted by Apoptotic Neuron and Lysophosphatidylcholine. Dev Cell 2016; 38:214-22. [PMID: 27424497 DOI: 10.1016/j.devcel.2016.06.018] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 05/13/2016] [Accepted: 06/15/2016] [Indexed: 02/08/2023]
Abstract
Microglia are CNS-resident macrophages and play important roles in neural development and function. However, how microglial precursors born in peripheral tissues colonize the CNS remains undefined. Using in vivo imaging and genetic manipulation of zebrafish, we showed that microglial precursors enter the optic tectum of the midbrain, where the majority of microglia reside during early development, via the lateral periphery between the eyes and brain and the ventral periphery of the brain in a circulation-independent manner. The colonization of the optic tectum by microglial precursors is dynamic and driven by apoptotic neuronal death, which occurs naturally in the midbrain during neurogenesis. We further show that lysophosphatidylcholine, a phospholipid known to be released from apoptotic cells, can promote microglial precursor entry into the brain via its cognate receptors grp132b. Our study reveals that microglia colonization of developing zebrafish midbrain is triggered by apoptotic neuronal death, possibly via releasing lysophosphatidylcholine.
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Affiliation(s)
- Jin Xu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China
| | - Tienan Wang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China
| | - Yi Wu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China
| | - Wan Jin
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China
| | - Zilong Wen
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China.
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56
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Casano A, Albert M, Peri F. Developmental Apoptosis Mediates Entry and Positioning of Microglia in the Zebrafish Brain. Cell Rep 2016; 16:897-906. [DOI: 10.1016/j.celrep.2016.06.033] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/11/2016] [Accepted: 06/03/2016] [Indexed: 01/15/2023] Open
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57
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Johnson K, Barragan J, Bashiruddin S, Smith CJ, Tyrrell C, Parsons MJ, Doris R, Kucenas S, Downes GB, Velez CM, Schneider C, Sakai C, Pathak N, Anderson K, Stein R, Devoto SH, Mumm JS, Barresi MJF. Gfap-positive radial glial cells are an essential progenitor population for later-born neurons and glia in the zebrafish spinal cord. Glia 2016; 64:1170-89. [PMID: 27100776 PMCID: PMC4918407 DOI: 10.1002/glia.22990] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 03/27/2016] [Accepted: 03/30/2016] [Indexed: 11/12/2022]
Abstract
Radial glial cells are presumptive neural stem cells (NSCs) in the developing nervous system. The direct requirement of radial glia for the generation of a diverse array of neuronal and glial subtypes, however, has not been tested. We employed two novel transgenic zebrafish lines and endogenous markers of NSCs and radial glia to show for the first time that radial glia are essential for neurogenesis during development. By using the gfap promoter to drive expression of nuclear localized mCherry we discerned two distinct radial glial-derived cell types: a major nestin+/Sox2+ subtype with strong gfap promoter activity and a minor Sox2+ subtype lacking this activity. Fate mapping studies in this line indicate that gfap+ radial glia generate later-born CoSA interneurons, secondary motorneurons, and oligodendroglia. In another transgenic line using the gfap promoter-driven expression of the nitroreductase enzyme, we induced cell autonomous ablation of gfap+ radial glia and observed a reduction in their specific derived lineages, but not Blbp+ and Sox2+/gfap-negative NSCs, which were retained and expanded at later larval stages. Moreover, we provide evidence supporting classical roles of radial glial in axon patterning, blood-brain barrier formation, and locomotion. Our results suggest that gfap+ radial glia represent the major NSC during late neurogenesis for specific lineages, and possess diverse roles to sustain the structure and function of the spinal cord. These new tools will both corroborate the predicted roles of astroglia and reveal novel roles related to development, physiology, and regeneration in the vertebrate nervous system. GLIA 2016;64:1170-1189.
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Affiliation(s)
- Kimberly Johnson
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts
| | - Jessica Barragan
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Sarah Bashiruddin
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Cody J Smith
- Department of Biology, University of Virginia, Charlottesville, Virginia
| | - Chelsea Tyrrell
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, Massachusetts
| | - Michael J Parsons
- Department of Surgery, Johns Hopkins University, Baltimore, Maryland
| | - Rosemarie Doris
- Department of Biology, Wesleyan University, Middletown, Connecticut
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, Virginia
| | - Gerald B Downes
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Carla M Velez
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Caitlin Schneider
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Catalina Sakai
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Narendra Pathak
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Katrina Anderson
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Rachael Stein
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
| | - Stephen H Devoto
- Department of Biology, Wesleyan University, Middletown, Connecticut
| | - Jeff S Mumm
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | - Michael J F Barresi
- Department of Biological Sciences, Smith College, Northampton, Massachusetts
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, Massachusetts
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58
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Eyo UB, Miner SA, Weiner JA, Dailey ME. Developmental changes in microglial mobilization are independent of apoptosis in the neonatal mouse hippocampus. Brain Behav Immun 2016; 55:49-59. [PMID: 26576723 PMCID: PMC4864211 DOI: 10.1016/j.bbi.2015.11.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/09/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
During CNS development, microglia transform from highly mobile amoeboid-like cells to primitive ramified forms and, finally, to highly branched but relatively stationary cells in maturity. The factors that control developmental changes in microglia are largely unknown. Because microglia detect and clear apoptotic cells, developmental changes in microglia may be controlled by neuronal apoptosis. Here, we assessed the extent to which microglial cell density, morphology, motility, and migration are regulated by developmental apoptosis, focusing on the first postnatal week in the mouse hippocampus when the density of apoptotic bodies peaks at postnatal day 4 and declines sharply thereafter. Analysis of microglial form and distribution in situ over the first postnatal week showed that, although there was little change in the number of primary microglial branches, microglial cell density increased significantly, and microglia were often seen near or engulfing apoptotic bodies. Time-lapse imaging in hippocampal slices harvested at different times over the first postnatal week showed differences in microglial motility and migration that correlated with the density of apoptotic bodies. The extent to which these changes in microglia are driven by developmental neuronal apoptosis was assessed in tissues from BAX null mice lacking apoptosis. We found that apoptosis can lead to local microglial accumulation near apoptotic neurons in the pyramidal cell body layer but, unexpectedly, loss of apoptosis did not alter overall microglial cell density in vivo or microglial motility and migration in ex vivo tissue slices. These results demonstrate that developmental changes in microglial form, distribution, motility, and migration occur essentially normally in the absence of developmental apoptosis, indicating that factors other than neuronal apoptosis regulate these features of microglial development.
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59
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Morsch M, Radford R, Lee A, Don EK, Badrock AP, Hall TE, Cole NJ, Chung R. In vivo characterization of microglial engulfment of dying neurons in the zebrafish spinal cord. Front Cell Neurosci 2015; 9:321. [PMID: 26379496 PMCID: PMC4553390 DOI: 10.3389/fncel.2015.00321] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 08/03/2015] [Indexed: 11/13/2022] Open
Abstract
Microglia are specialized phagocytes in the vertebrate central nervous system (CNS). As the resident immune cells of the CNS they play an important role in the removal of dying neurons during both development and in several neuronal pathologies. Microglia have been shown to prevent the diffusion of damaging degradation products of dying neurons by engulfment and ingestion. Here we describe a live imaging approach that uses UV laser ablation to selectively stress and kill spinal neurons and visualize the clearance of neuronal remnants by microglia in the zebrafish spinal cord. In vivo imaging confirmed the motile nature of microglia within the uninjured spinal cord. However, selective neuronal ablation triggered rapid activation of microglia, leading to phagocytic uptake of neuronal debris by microglia within 20-30 min. This process of microglial engulfment is highly dynamic, involving the extension of processes toward the lesion site and consequently the ingestion of the dying neuron. 3D rendering analysis of time-lapse recordings revealed the formation of phagosome-like structures in the activated microglia located at the site of neuronal ablation. This real-time representation of microglial phagocytosis in the living zebrafish spinal cord provides novel opportunities to study the mechanisms of microglia-mediated neuronal clearance.
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Affiliation(s)
- Marco Morsch
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Rowan Radford
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Albert Lee
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Emily K Don
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Andrew P Badrock
- Faculty of Life Sciences, The University of Manchester Manchester, UK
| | - Thomas E Hall
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland Brisbane, QLD, Australia
| | - Nicholas J Cole
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
| | - Roger Chung
- Motor Neuron Disease Research Group, Faculty of Medicine and Health Sciences, Macquarie University Sydney, NSW, Australia
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60
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Svahn AJ, Giacomotto J, Graeber MB, Rinkwitz S, Becker TS. miR-124 Contributes to the functional maturity of microglia. Dev Neurobiol 2015; 76:507-18. [PMID: 26184457 DOI: 10.1002/dneu.22328] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 12/31/2022]
Abstract
During early development of the central nervous system (CNS), a subset of yolk-sac derived myeloid cells populate the brain and provide the seed for the microglial cell population, which will self-renew throughout life. As development progresses, individual microglial cells transition from a phagocytic amoeboid state through a transitional morphing phase into the sessile, ramified, and normally nonphagocytic microglia observed in the adult CNS under healthy conditions. The molecular drivers of this tissue-specific maturation profile are not known. However, a survey of tissue resident macrophages identified miR-124 to be expressed in microglia. In this study, we used transgenic zebrafish to overexpress miR-124 in the mpeg1 expressing yolk-sac-derived myeloid cells that seed the microglia. In addition, a systemic sponge designed to neutralize the effects of miR-124 was used to assess microglial development in a miR-124 loss-of-function environment. Following the induction of miR-124 overexpression, microglial motility and phagocytosis of apoptotic cells were significantly reduced. miR-124 overexpression in microglia resulted in the accumulation of residual apoptotic cell bodies in the optic tectum, which could not be achieved by miR-124 overexpression in differentiated neurons. Conversely, expression of the miR-124 sponge caused an increase in the motility of microglia and transiently rescued motility and phagocytosis functions when activated simultaneously with miR-124 overexpression. This study provides in vivo evidence that miR-124 activity has a key role in the development of functionally mature microglia.
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Affiliation(s)
- Adam J Svahn
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Jean Giacomotto
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Manuel B Graeber
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Sydney, Australia.,Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - Silke Rinkwitz
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Physiology and School of Medicine, University of Sydney, Sydney, Australia
| | - Thomas S Becker
- Brain and Mind Research Institute, Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Physiology and School of Medicine, University of Sydney, Sydney, Australia
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61
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Rossi F, Casano AM, Henke K, Richter K, Peri F. The SLC7A7 Transporter Identifies Microglial Precursors prior to Entry into the Brain. Cell Rep 2015; 11:1008-17. [PMID: 25959825 DOI: 10.1016/j.celrep.2015.04.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/10/2015] [Accepted: 04/13/2015] [Indexed: 01/13/2023] Open
Abstract
During development, macrophages invade organs to establish phenotypically and transcriptionally distinct tissue-resident populations. How they invade and colonize these organs is unclear. In particular, it remains to be established whether they arise from naive equivalents that colonize organs randomly or whether there are committed macrophages that follow pre-determined migration paths. Here, by using a combination of genetics and imaging approaches in the zebrafish embryo, we have addressed how macrophages colonize the brain to become microglia. Identification and cloning of a mutant that lacks microglia has shown that Slc7a7, a Leucine/Arginine transporter, defines a restricted macrophage sub-lineage and is necessary for brain colonization. By taking a photoconversion approach, we show that these macrophages give rise to microglia. This study provides direct experimental evidence for the existence of sub-lineages among embryonic macrophages.
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Affiliation(s)
- Federico Rossi
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidbelberg, Germany
| | - Alessandra Maria Casano
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidbelberg, Germany
| | - Katrin Henke
- Department of Genetics, Max-Planck Institute (MPI) for Developmental Biology, Spemannstraße 35-39, 72076 Tübingen, Germany
| | - Kerstin Richter
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidbelberg, Germany
| | - Francesca Peri
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidbelberg, Germany.
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62
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Solchenberger B, Russell C, Kremmer E, Haass C, Schmid B. Granulin knock out zebrafish lack frontotemporal lobar degeneration and neuronal ceroid lipofuscinosis pathology. PLoS One 2015; 10:e0118956. [PMID: 25785851 PMCID: PMC4365039 DOI: 10.1371/journal.pone.0118956] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 01/26/2015] [Indexed: 02/04/2023] Open
Abstract
Loss of function mutations in granulin (GRN) are linked to two distinct neurological disorders, frontotemporal lobar degeneration (FTLD) and neuronal ceroid lipofuscinosis (NCL). It is so far unknown how a complete loss of GRN in NCL and partial loss of GRN in FTLD can result in such distinct diseases. In zebrafish, there are two GRN homologues, Granulin A (Grna) and Granulin B (Grnb). We have generated stable Grna and Grnb loss of function zebrafish mutants by zinc finger nuclease mediated genome editing. Surprisingly, the grna and grnb single and double mutants display neither spinal motor neuron axonopathies nor a reduced number of myogenic progenitor cells as previously reported for Grna and Grnb knock down embryos. Additionally, grna−/−;grnb−/− double mutants have no obvious FTLD- and NCL-related biochemical and neuropathological phenotypes. Taken together, the Grna and Grnb single and double knock out zebrafish lack any obvious morphological, pathological and biochemical phenotypes. Loss of zebrafish Grna and Grnb might therefore either be fully compensated or only become symptomatic upon additional challenge.
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Affiliation(s)
- Barbara Solchenberger
- Adolf-Butenandt-Institute—Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Claire Russell
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Elisabeth Kremmer
- Institute of Molecular Immunology, Helmholtz Center Munich, Munich, Germany
| | - Christian Haass
- Adolf-Butenandt-Institute—Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Bettina Schmid
- Adolf-Butenandt-Institute—Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
- * E-mail:
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63
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van Ham TJ, Brady CA, Kalicharan RD, Oosterhof N, Kuipers J, Veenstra-Algra A, Sjollema KA, Peterson RT, Kampinga HH, Giepmans BNG. Intravital correlated microscopy reveals differential macrophage and microglial dynamics during resolution of neuroinflammation. Dis Model Mech 2015; 7:857-69. [PMID: 24973753 PMCID: PMC4073275 DOI: 10.1242/dmm.014886] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Many brain diseases involve activation of resident and peripheral immune cells to clear damaged and dying neurons. Which immune cells respond in what way to cues related to brain disease, however, remains poorly understood. To elucidate these in vivo immunological events in response to brain cell death we used genetically targeted cell ablation in zebrafish. Using intravital microscopy and large-scale electron microscopy, we defined the kinetics and nature of immune responses immediately following injury. Initially, clearance of dead cells occurs by mononuclear phagocytes, including resident microglia and macrophages of peripheral origin, whereas amoeboid microglia are exclusively involved at a later stage. Granulocytes, on the other hand, do not migrate towards the injury. Remarkably, following clearance, phagocyte numbers decrease, partly by phagocyte cell death and subsequent engulfment of phagocyte corpses by microglia. Here, we identify differential temporal involvement of microglia and peripheral macrophages in clearance of dead cells in the brain, revealing the chronological sequence of events in neuroinflammatory resolution. Remarkably, recruited phagocytes undergo cell death and are engulfed by microglia. Because adult zebrafish treated at the larval stage lack signs of pathology, it is likely that this mode of resolving immune responses in brain contributes to full tissue recovery. Therefore, these findings suggest that control of such immune cell behavior could benefit recovery from neuronal damage.
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Affiliation(s)
- Tjakko J van Ham
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands.
| | - Colleen A Brady
- Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA
| | - Ruby D Kalicharan
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Nynke Oosterhof
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Jeroen Kuipers
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Anneke Veenstra-Algra
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Klaas A Sjollema
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Randall T Peterson
- Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA
| | - Harm H Kampinga
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Ben N G Giepmans
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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Torraca V, Masud S, Spaink HP, Meijer AH. Macrophage-pathogen interactions in infectious diseases: new therapeutic insights from the zebrafish host model. Dis Model Mech 2015; 7:785-97. [PMID: 24973749 PMCID: PMC4073269 DOI: 10.1242/dmm.015594] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Studying macrophage biology in the context of a whole living organism provides unique possibilities to understand the contribution of this extremely dynamic cell subset in the reaction to infections, and has revealed the relevance of cellular and molecular processes that are fundamental to the cell-mediated innate immune response. In particular, various recently established zebrafish infectious disease models are contributing substantially to our understanding of the mechanisms by which different pathogens interact with macrophages and evade host innate immunity. Transgenic zebrafish lines with fluorescently labeled macrophages and other leukocyte populations enable non-invasive imaging at the optically transparent early life stages. Furthermore, there is a continuously expanding availability of vital reporters for subcellular compartments and for probing activation of immune defense mechanisms. These are powerful tools to visualize the activity of phagocytic cells in real time and shed light on the intriguing paradoxical roles of these cells in both limiting infection and supporting the dissemination of intracellular pathogens. This Review will discuss how several bacterial and fungal infection models in zebrafish embryos have led to new insights into the dynamic molecular and cellular mechanisms at play when pathogens encounter host macrophages. We also describe how these insights are inspiring novel therapeutic strategies for infectious disease treatment.
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Affiliation(s)
- Vincenzo Torraca
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Samrah Masud
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Herman P Spaink
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Annemarie H Meijer
- Institute of Biology, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
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Shiau CE, Kaufman Z, Meireles AM, Talbot WS. Differential requirement for irf8 in formation of embryonic and adult macrophages in zebrafish. PLoS One 2015; 10:e0117513. [PMID: 25615614 PMCID: PMC4304715 DOI: 10.1371/journal.pone.0117513] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/28/2014] [Indexed: 12/21/2022] Open
Abstract
Interferon regulatory factor 8 (Irf8) is critical for mammalian macrophage development and innate immunity, but its role in teleost myelopoiesis remains incompletely understood. In particular, genetic tools to analyze the role of Irf8 in zebrafish macrophage development at larval and adult stages are lacking. We generated irf8 null mutants in zebrafish using TALEN-mediated targeting. Our analysis defines different requirements for irf8 at different stages. irf8 is required for formation of all macrophages during primitive and transient definitive hematopoiesis, but not during adult-phase definitive hematopoiesis starting at 5-6 days postfertilization. At early stages, irf8 mutants have excess neutrophils and excess cell death in pu.1-expressing myeloid cells. Macrophage fates were recovered in irf8 mutants after wildtype irf8 expression in neutrophil and macrophage lineages, suggesting that irf8 regulates macrophage specification and survival. In juvenile irf8 mutant fish, mature macrophages are present, but at numbers significantly reduced compared to wildtype, indicating an ongoing requirement for irf8 after embryogenesis. As development progresses, tissue macrophages become apparent in zebrafish irf8 mutants, with the possible exception of microglia. Our study defines distinct requirement for irf8 in myelopoiesis before and after transition to the adult hematopoietic system.
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Affiliation(s)
- Celia E. Shiau
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (WST); (CES)
| | - Zoe Kaufman
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Ana M. Meireles
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - William S. Talbot
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (WST); (CES)
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66
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Argente-Arizón P, Freire-Regatillo A, Argente J, Chowen JA. Role of non-neuronal cells in body weight and appetite control. Front Endocrinol (Lausanne) 2015; 6:42. [PMID: 25859240 PMCID: PMC4374626 DOI: 10.3389/fendo.2015.00042] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/11/2015] [Indexed: 12/14/2022] Open
Abstract
The brain is composed of neurons and non-neuronal cells, with the latter encompassing glial, ependymal and endothelial cells, as well as pericytes and progenitor cells. Studies aimed at understanding how the brain operates have traditionally focused on neurons, but the importance of non-neuronal cells has become increasingly evident. Once relegated to supporting roles, it is now indubitable that these diverse cell types are fundamental for brain development and function, including that of metabolic circuits, and they may play a significant role in obesity onset and complications. They participate in processes of neurogenesis, synaptogenesis, and synaptic plasticity of metabolic circuits both during development and in adulthood. Some glial cells, such as tanycytes and astrocytes, transport circulating nutrients and metabolic factors that are fundamental for neuronal viability and activity into and within the hypothalamus. All of these cell types express receptors for a variety of metabolic factors and hormones, suggesting that they participate in metabolic function. They are the first line of defense against any assault to neurons. Indeed, microglia and astrocytes participate in the hypothalamic inflammatory response to high fat diet (HFD)-induced obesity, with this process contributing to inflammatory-related insulin and leptin resistance. Moreover, HFD-induced obesity and hyperleptinemia modify hypothalamic astroglial morphology, which is associated with changes in the synaptic inputs to neuronal metabolic circuits. Astrocytic contact with the microvasculature is increased by HFD intake and this could modify nutrient/hormonal uptake into the brain. In addition, progenitor cells in the hypothalamus are now known to have the capacity to renew metabolic circuits, and this can be affected by HFD intake and obesity. Here, we discuss our current understanding of how non-neuronal cells participate in physiological and physiopathological metabolic control.
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Affiliation(s)
- Pilar Argente-Arizón
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
- Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centros de Investigación Biomédica en Red, Instituto de Salud Carlos III, Madrid, Spain
| | - Alejandra Freire-Regatillo
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
- Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centros de Investigación Biomédica en Red, Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Argente
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Department of Pediatrics, Universidad Autónoma de Madrid, Madrid, Spain
- Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centros de Investigación Biomédica en Red, Instituto de Salud Carlos III, Madrid, Spain
| | - Julie A. Chowen
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain
- Fisiopatología de la Obesidad y Nutrición (CIBERobn), Centros de Investigación Biomédica en Red, Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Julie A. Chowen, Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Avda. Menéndez Pelayo, 65, Madrid E-28009, Spain e-mail: ;
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67
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Abstract
The zebrafish is a premier vertebrate model system that offers many experimental advantages for in vivo imaging and genetic studies. This review provides an overview of glial cell types in the central and peripheral nervous system of zebrafish. We highlight some recent work that exploited the strengths of the zebrafish system to increase the understanding of the role of Gpr126 in Schwann cell myelination and illuminate the mechanisms controlling oligodendrocyte development and myelination. We also summarize similarities and differences between zebrafish radial glia and mammalian astrocytes and consider the possibility that their distinct characteristics may represent extremes in a continuum of cell identity. Finally, we focus on the emergence of zebrafish as a model for elucidating the development and function of microglia. These recent studies have highlighted the power of the zebrafish system for analyzing important aspects of glial development and function.
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Affiliation(s)
- David A Lyons
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom
| | - William S Talbot
- Department of Developmental Biology, Stanford University, Stanford, California 94305
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68
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Svahn AJ, Becker TS, Graeber MB. Emergent properties of microglia. Brain Pathol 2014; 24:665-70. [PMID: 25345896 PMCID: PMC8029137 DOI: 10.1111/bpa.12195] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 08/07/2014] [Indexed: 12/31/2022] Open
Abstract
More than 80 years ago, Pio Del Rio-Hortega recognized that one of the "main controversial points in regard to the microglia" is "whether it belongs to the reticulo-endothelial system [i.e. monocytes and macrophages] and possesses the ordinary characteristics of this system or has a more specialized function." The notion of microglia having functions that are different from those of other macrophages has gained significant support in recent years. The brain represents a unique environment and shows species, developmental and regional specialization. Thus, any consideration of microglial activity has to be thought of in this tissue context. Contexts may be normal (health, physiology) or disease conditions showing either primary or secondary microglial involvement. Subclinical, reversible "soft pathologies" (Kreutzberg) such as pain that involves microglia also exist. Here, we examine a multilayered approach to understanding microglia that illustrates the emergent character of the microglial (population) phenotype. Accordingly, terms such as microglial "activation" and microgliosis, which are of increasing importance for our understanding of neurological disorders, need to be filled with refined meaning. It is suggested that the pathophysiological context guides nomenclatorial considerations; for example, development, trauma or pain-associated microglia is preferred over the traditional but less distinctive "microglial activation." This should also help to tease out the different functional subtypes currently hidden under the umbrella term "neuroinflammation," which is being applied so widely that it has become effectively useless in practice and even inhibits research progress because both true and pseudo-inflammation are covered by this term.
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Affiliation(s)
- Adam J. Svahn
- Developmental Neurobiology LaboratoryUniversity of SydneySydneyNSWAustralia
| | - Thomas S. Becker
- Developmental Neurobiology LaboratoryUniversity of SydneySydneyNSWAustralia
| | - Manuel B. Graeber
- Brain Tumor Research LaboratoriesBrain and Mind Research InstituteFaculty of Medicine and Faculty of Health SciencesUniversity of SydneySydneyNSWAustralia
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69
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70
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The phosphate exporter xpr1b is required for differentiation of tissue-resident macrophages. Cell Rep 2014; 8:1659-1667. [PMID: 25220463 DOI: 10.1016/j.celrep.2014.08.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/23/2014] [Accepted: 08/08/2014] [Indexed: 12/23/2022] Open
Abstract
Phosphate concentration is tightly regulated at the cellular and organismal levels. The first metazoan phosphate exporter, XPR1, was recently identified, but its in vivo function remains unknown. In a genetic screen, we identified a mutation in a zebrafish ortholog of human XPR1, xpr1b. xpr1b mutants lack microglia, the specialized macrophages that reside in the brain, and also displayed an osteopetrotic phenotype characteristic of defects in osteoclast function. Transgenic expression studies indicated that xpr1b acts autonomously in developing macrophages. xpr1b mutants display no gross developmental defects that may arise from phosphate imbalance. We constructed a targeted mutation of xpr1a, a duplicate of xpr1b in the zebrafish genome, to determine whether Xpr1a and Xpr1b have redundant functions. Single mutants for xpr1a were viable, and double mutants for xpr1b;xpr1a were similar to xpr1b single mutants. Our genetic analysis reveals a specific role for the phosphate exporter Xpr1 in the differentiation of tissue macrophages.
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71
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Bloom O. Non-mammalian model systems for studying neuro-immune interactions after spinal cord injury. Exp Neurol 2014; 258:130-40. [PMID: 25017894 PMCID: PMC4099969 DOI: 10.1016/j.expneurol.2013.12.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/24/2013] [Accepted: 12/26/2013] [Indexed: 01/09/2023]
Abstract
Mammals exhibit poor recovery after injury to the spinal cord, where the loss of neurons and neuronal connections can be functionally devastating. In contrast, it has long been appreciated that many non-mammalian vertebrate species exhibit significant spontaneous functional recovery after spinal cord injury (SCI). Identifying the biological responses that support an organism's inability or ability to recover function after SCI is an important scientific and medical question. While recent advances have been made in understanding the responses to SCI in mammals, we remain without an effective clinical therapy for SCI. A comparative biological approach to understanding responses to SCI in non-mammalian vertebrates will yield important insights into mechanisms that promote recovery after SCI. Presently, mechanistic studies aimed at elucidating responses, both intrinsic and extrinsic to neurons, that result in different regenerative capacities after SCI across vertebrates are just in their early stages. There are several inhibitory mechanisms proposed to impede recovery from SCI in mammals, including reactive gliosis and scarring, myelin associated proteins, and a suboptimal immune response. One hypothesis to explain the robust regenerative capacity of several non-mammalian vertebrates is a lack of some or all of these inhibitory signals. This review presents the current knowledge of immune responses to SCI in several non-mammalian species that achieve anatomical and functional recovery after SCI. This subject is of growing interest, as studies increasingly show both beneficial and detrimental roles of the immune response following SCI in mammals. A long-term goal of biomedical research in all experimental models of SCI is to understand how to promote functional recovery after SCI in humans. Therefore, understanding immune responses to SCI in non-mammalian vertebrates that achieve functional recovery spontaneously may identify novel strategies to modulate immune responses in less regenerative species and promote recovery after SCI.
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Affiliation(s)
- Ona Bloom
- The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA; The Hofstra North Shore-LIJ School of Medicine, Hempstead Turnpike, Hempstead, NY 11549, USA.
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72
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Kyritsis N, Kizil C, Brand M. Neuroinflammation and central nervous system regeneration in vertebrates. Trends Cell Biol 2013; 24:128-35. [PMID: 24029244 DOI: 10.1016/j.tcb.2013.08.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/09/2013] [Accepted: 08/12/2013] [Indexed: 01/11/2023]
Abstract
Injuries in the central nervous system (CNS) are one of the leading causes of mortality or persistent disabilities in humans. One of the reasons why humans cannot recover from neuronal loss is the limited regenerative capacity of their CNS. By contrast, non-mammalian vertebrates exhibit widespread regeneration in diverse tissues including the CNS. Understanding those mechanisms activated during regeneration may improve the regenerative outcome in the severed mammalian CNS. Of those mechanisms, recent evidence suggests that inflammation may be important in regeneration. In this review we compare the different events following acute CNS injury in mammals and non-mammalian vertebrates. We also discuss the involvement of the immune response in initiating regenerative programs and how immune cells and neural stem/progenitor cells (NSPCs) communicate.
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Affiliation(s)
- Nikos Kyritsis
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Caghan Kizil
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany
| | - Michael Brand
- DFG Center for Regenerative Therapies Dresden - Cluster of Excellence (CRTD), Technische Universität Dresden, Fetscherstraße 105, 01307, Dresden, Germany.
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73
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Singh SK, Sethi S, Aravamudhan S, Krüger M, Grabher C. Proteome mapping of adult zebrafish marrow neutrophils reveals partial cross species conservation to human peripheral neutrophils. PLoS One 2013; 8:e73998. [PMID: 24019943 PMCID: PMC3760823 DOI: 10.1371/journal.pone.0073998] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 07/30/2013] [Indexed: 11/18/2022] Open
Abstract
Neutrophil granulocytes are pivotal cells within the first line of host defense of the innate immune system. In this study, we have used a gel-based LC-MS/MS approach to explore the proteome of primary marrow neutrophils from adult zebrafish. The identified proteins originated from all major cellular compartments. Gene ontology analysis revealed significant association of proteins with different immune-related network and pathway maps. 75% of proteins identified in neutrophils were identified in neutrophils only when compared to neutrophil-free brain tissue. Moreover, cross-species comparison with human peripheral blood neutrophils showed partial conservation of immune-related proteins between human and zebrafish. This study provides the first zebrafish neutrophil proteome and may serve as a valuable resource for an understanding of neutrophil biology and innate immunity.
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Affiliation(s)
- Sachin Kumar Singh
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sachin Sethi
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | | | - Marcus Krüger
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Clemens Grabher
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
- * E-mail:
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74
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Eyo UB, Dailey ME. Microglia: key elements in neural development, plasticity, and pathology. J Neuroimmune Pharmacol 2013; 8:494-509. [PMID: 23354784 DOI: 10.1007/s11481-013-9434-z] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 01/14/2013] [Indexed: 12/31/2022]
Abstract
A century after Cajal identified a "third element" of the nervous system, many issues have been clarified about the identity and function of one of its major components, the microglia. Here, we review recent findings by microgliologists, highlighting results from imaging studies that are helping provide new views of microglial behavior and function. In vivo imaging in the intact adult rodent CNS has revolutionized our understanding of microglial behaviors in situ and has raised speculation about their function in the uninjured adult brain. Imaging studies in ex vivo mammalian tissue preparations and in intact model organisms including zebrafish are providing insights into microglial behaviors during brain development. These data suggest that microglia play important developmental roles in synapse remodeling, developmental apoptosis, phagocytic clearance, and angiogenesis. Because microglia also contribute to pathology, including neurodevelopmental and neurobehavioral disorders, ischemic injury, and neuropathic pain, promising new results raise the possibility of leveraging microglia for therapeutic roles. Finally, exciting recent work is addressing unanswered questions regarding the nature of microglial-neuronal communication. While it is now apparent that microglia play diverse roles in neural development, behavior, and pathology, future research using neuroimaging techniques will be essential to more fully exploit these intriguing cellular targets for effective therapeutic intervention applied to a variety of conditions.
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Affiliation(s)
- Ukpong B Eyo
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
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75
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Abstract
Hematopoiesis is well-conserved between Drosophila and vertebrates. Similar as in vertebrates, the sites of hematopoiesis shift during Drosophila development. Blood cells (hemocytes) originate de novo during hematopoietic waves in the embryo and in the Drosophila lymph gland. In contrast, the hematopoietic wave in the larva is based on the colonization of resident hematopoietic sites by differentiated hemocytes that arise in the embryo, much like in vertebrates the colonization of peripheral tissues by primitive macrophages of the yolk sac, or the seeding of fetal liver, spleen and bone marrow by hematopoietic stem and progenitor cells. At the transition to the larval stage, Drosophila embryonic hemocytes retreat to hematopoietic "niches," i.e., segmentally repeated hematopoietic pockets of the larval body wall that are jointly shared with sensory neurons and other cells of the peripheral nervous system (PNS). Hemocytes rely on the PNS for their localization and survival, and are induced to proliferate in these microenvironments, expanding to form the larval hematopoietic system. In this process, differentiated hemocytes from the embryo resume proliferation and self-renew, omitting the need for an undifferentiated prohemocyte progenitor. Larval hematopoiesis is the first Drosophila model for blood cell colonization and niche support by the PNS. It suggests an interface where innocuous or noxious sensory inputs regulate blood cell homeostasis or immune responses. The system adds to the growing concept of nervous system dependence of hematopoietic microenvironments and organ stem cell niches, which is being uncovered across phyla.
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Affiliation(s)
- Kalpana Makhijani
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research; University of California, San Francisco; San Francisco, CA USA
- Department of Cell and Tissue Biology; University of California, San Francisco; San Francisco, CA USA
| | - Katja Brückner
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research; University of California, San Francisco; San Francisco, CA USA
- Department of Cell and Tissue Biology; University of California, San Francisco; San Francisco, CA USA
- Department of Anatomy; University of California, San Francisco; San Francisco, CA USA
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