1
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Barry-Carroll L, Gomez-Nicola D. The molecular determinants of microglial developmental dynamics. Nat Rev Neurosci 2024; 25:414-427. [PMID: 38658739 DOI: 10.1038/s41583-024-00813-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2024] [Indexed: 04/26/2024]
Abstract
Microglia constitute the largest population of parenchymal macrophages in the brain and are considered a unique subset of central nervous system glial cells owing to their extra-embryonic origins in the yolk sac. During development, microglial progenitors readily proliferate and eventually colonize the entire brain. In this Review, we highlight the origins of microglial progenitors and their entry routes into the brain and discuss the various molecular and non-molecular determinants of their fate, which may inform their specific functions. Specifically, we explore recently identified mechanisms that regulate microglial colonization of the brain, including the availability of space, and describe how the expansion of highly proliferative microglial progenitors facilitates the occupation of the microglial niche. Finally, we shed light on the factors involved in establishing microglial identity in the brain.
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Affiliation(s)
- Liam Barry-Carroll
- Nutrineuro, UMR 1286 INRAE, Bordeaux University, Bordeaux INP, Bordeaux, France
| | - Diego Gomez-Nicola
- School of Biological Sciences, University of Southampton, Southampton General Hospital, Southampton, UK.
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2
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You Y, Chen Z, Hu WW. The role of microglia heterogeneity in synaptic plasticity and brain disorders: Will sequencing shed light on the discovery of new therapeutic targets? Pharmacol Ther 2024; 255:108606. [PMID: 38346477 DOI: 10.1016/j.pharmthera.2024.108606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/05/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Microglia play a crucial role in interacting with neuronal synapses and modulating synaptic plasticity. This function is particularly significant during postnatal development, as microglia are responsible for removing excessive synapses to prevent neurodevelopmental deficits. Dysregulation of microglial synaptic function has been well-documented in various pathological conditions, notably Alzheimer's disease and multiple sclerosis. The recent application of RNA sequencing has provided a powerful and unbiased means to decipher spatial and temporal microglial heterogeneity. By identifying microglia with varying gene expression profiles, researchers have defined multiple subgroups of microglia associated with specific pathological states, including disease-associated microglia, interferon-responsive microglia, proliferating microglia, and inflamed microglia in multiple sclerosis, among others. However, the functional roles of these distinct subgroups remain inadequately characterized. This review aims to refine our current understanding of the potential roles of heterogeneous microglia in regulating synaptic plasticity and their implications for various brain disorders, drawing from recent sequencing research and functional studies. This knowledge may aid in the identification of pathogenetic biomarkers and potential factors contributing to pathogenesis, shedding new light on the discovery of novel drug targets. The field of sequencing-based data mining is evolving toward a multi-omics approach. With advances in viral tools for precise microglial regulation and the development of brain organoid models, we are poised to elucidate the functional roles of microglial subgroups detected through sequencing analysis, ultimately identifying valuable therapeutic targets.
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Affiliation(s)
- Yi You
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhong Chen
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Wei-Wei Hu
- Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China.
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3
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Sun J, Wang X, Sun R, Xiao X, Wang Y, Peng Y, Gao Y. Microglia shape AgRP neuron postnatal development via regulating perineuronal net plasticity. Mol Psychiatry 2024; 29:306-316. [PMID: 38001338 DOI: 10.1038/s41380-023-02326-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/31/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023]
Abstract
The hypothalamus plays a crucial role in controlling metabolism and energy balance, with Agouti-related protein (AgRP) neurons and proopiomelanocortin (POMC) neurons being essential components of this process. The proper development of these neurons is important for metabolic regulation in later life. Microglia, the resident immune cells in the brain, have been shown to significantly influence neurodevelopment. However, their role in shaping the postnatal development of hypothalamic neural circuits remains underexplored. In this study, we investigated the dynamic changes of microglia in the hypothalamic arcuate nucleus (ARC) during lactation and their impact on the maturation of AgRP and POMC neurons. We demonstrated that microglial depletion during a critical period of ARC neuron maturation increases the number of AgRP neurons and fiber density, with less effect on POMC neurons. This depletion also resulted in increased neonatal feeding behavior. Mechanistically, microglia can engulf perineuronal net (PNN) components surrounding AgRP neurons both in vivo and ex vivo. The absence of microglia leads to increased PNN formation and enhanced leptin sensitivity in ARC. Our findings suggest that microglia participate in the postnatal development of AgRP neurons by regulating the plasticity of PNN formation. This study contributes to a better understanding of microglia's role in shaping hypothalamic neural circuits during postnatal development and their impact on metabolism regulation.
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Affiliation(s)
- Jia Sun
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Xinyuan Wang
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
- Geriatric Hospital of Nanjing Medical University, Nanjing, 210009, P. R. China
| | - Rui Sun
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Xiaoao Xiao
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yu Wang
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yu Peng
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China
| | - Yuanqing Gao
- Key Laboratory of Cardiovascular and Cerebrovascular Medicine, School of Pharmacy, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, P. R. China.
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4
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Marín-Teva JL, Sepúlveda MR, Neubrand VE, Cuadros MA. Microglial Phagocytosis During Embryonic and Postnatal Development. ADVANCES IN NEUROBIOLOGY 2024; 37:151-161. [PMID: 39207691 DOI: 10.1007/978-3-031-55529-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Microglia play decisive roles during the development of the central nervous system (CNS). Phagocytosis is one of the classical functions attributed to microglia, being involved in nearly all phases of the embryonic and postnatal development of the brain, such as rapid clearance of cell debris to avoid an inflammatory response, controlling the number of neuronal and glial cells or their precursors, contribution to axon guidance and to refinement of synaptic connections. To carry out all these tasks, microglial cells are equipped with a panoply of receptors, that convert microglia to the "professional phagocytes" of the nervous parenchyma. These receptors are modulated by spatiotemporal cues that adapt the properties of microglia to the needs of the developing CNS. Thus, in this chapter, we will discuss the role of microglial phagocytosis in all the aforementioned processes. First, we will explain the general phagocytic process, to describe afterward the performance of microglial cells in detail.
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Affiliation(s)
- José L Marín-Teva
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain.
| | - M Rosario Sepúlveda
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Veronika E Neubrand
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Miguel A Cuadros
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
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5
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Olmedillas M, Brawek B, Li K, Richter C, Garaschuk O. Plaque vicinity as a hotspot of microglial turnover in a mouse model of Alzheimer's disease. Glia 2023; 71:2884-2901. [PMID: 37596829 DOI: 10.1002/glia.24458] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/25/2023] [Accepted: 08/04/2023] [Indexed: 08/20/2023]
Abstract
Microglia, the major immune cells of the brain, are functionally heterogeneous but in vivo functional properties of these cells are rarely studied at single-cell resolution. By using microRNA-9 regulated viral vectors for multicolor labeling and longitudinal in vivo monitoring of individual microglia, we followed their fate in the cortex of healthy adult mice and at the onset of amyloidosis in a mouse model of Alzheimer's disease. In wild-type mice, microglia were rather mobile (16% of the cells migrated at least once in 10-20 days) but had a low turnover as documented by low division and death rates. Half of the migratory events were tightly associated with blood vessels. Surprisingly, basic migration properties of microglia (i.e., fraction of migrating cells, saltatory migration pattern, speed of migration, translocation distance, and strong association with blood vessels) were preserved in amyloid-depositing brains, despite amyloid plaques becoming the major destination of migration. Besides, amyloid deposition significantly increased microglial division and death rates. Moreover, the plaque vicinity became a hotspot of microglial turnover, harboring 33% of all migration, 70% of death and 54% of division events.
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Affiliation(s)
- Maria Olmedillas
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Kaizhen Li
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Cris Richter
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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6
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Deivasigamani S, Miteva MT, Natale S, Gutierrez-Barragan D, Basilico B, Di Angelantonio S, Weinhard L, Molotkov D, Deb S, Pape C, Bolasco G, Galbusera A, Asari H, Gozzi A, Ragozzino D, Gross CT. Microglia complement signaling promotes neuronal elimination and normal brain functional connectivity. Cereb Cortex 2023; 33:10750-10760. [PMID: 37718159 PMCID: PMC10629900 DOI: 10.1093/cercor/bhad313] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/19/2023] Open
Abstract
Complement signaling is thought to serve as an opsonization signal to promote the phagocytosis of synapses by microglia. However, while its role in synaptic remodeling has been demonstrated in the retino-thalamic system, it remains unclear whether complement signaling mediates synaptic pruning in the brain more generally. Here we found that mice lacking the Complement receptor 3, the major microglia complement receptor, failed to show a deficit in either synaptic pruning or axon elimination in the developing mouse cortex. Instead, mice lacking Complement receptor 3 exhibited a deficit in the perinatal elimination of neurons in the cortex, a deficit that is associated with increased cortical thickness and enhanced functional connectivity in these regions in adulthood. These data demonstrate a role for complement in promoting neuronal elimination in the developing cortex.
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Affiliation(s)
- Senthilkumar Deivasigamani
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Mariya T Miteva
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
- Neuroscience Masters Programme, Sapienza University, Piazza Aldo Moro 1, 00185 Roma, Italy
| | - Silvia Natale
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy
| | - Daniel Gutierrez-Barragan
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Bernadette Basilico
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Laetitia Weinhard
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Dmitry Molotkov
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Sukrita Deb
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Constantin Pape
- Cell Biology and Biophysics Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Giulia Bolasco
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Alberto Galbusera
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Hiroki Asari
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Alessandro Gozzi
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Via Ardeatina, 00179 Rome, Italy
| | - Cornelius T Gross
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
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7
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Gordon H, Schafer ZT, Smith CJ. A paradox promoted by microglia cannibalism shortens the lifespan of developmental microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532426. [PMID: 36993267 PMCID: PMC10055159 DOI: 10.1101/2023.03.15.532426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The overproduction of cells and subsequent production of debris is a universal principle of neurodevelopment. Here we show an additional feature of the developing nervous system that causes neural debris - promoted by the sacrificial nature of embryonic microglia that irreversibly become phagocytic after clearing other neural debris. Described as long-lived, microglia colonize the embryonic brain and persist into adulthood. Using transgenic zebrafish to investigate the microglia debris during brain construction, we identified that unlike other neural cell-types that die in developmental stages after they have expanded, necroptotic-dependent microglial debris is prevalent when microglia are expanding in the zebrafish brain. Time-lapse imaging of microglia demonstrates that this debris is cannibalized by other microglia. To investigate features that promote microglia death and cannibalism, we used time-lapse imaging and fate-mapping strategies to track the lifespan of individual developmental microglia. These approaches revealed that instead of embryonic microglia being long-lived cells that completely digest their phagocytic debris, once most developmental microglia in zebrafish become phagocytic they eventually die, including ones that are cannibalistic. These results establish a paradox -- which we tested by increasing neural debris and manipulating phagocytosis -- that once most microglia in the embryo become phagocytic, they die, create debris and then are cannibalized by other microglia, resulting in more phagocytic microglia that are destined to die.
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Affiliation(s)
- Hannah Gordon
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
- The Center for Stem Cells and Regenerative Medicine at the University of Notre Dame, Notre Dame, IN
| | - Zachary T. Schafer
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
| | - Cody J. Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN
- The Center for Stem Cells and Regenerative Medicine at the University of Notre Dame, Notre Dame, IN
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8
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Balbi M, Bonanno G, Bonifacino T, Milanese M. The Physio-Pathological Role of Group I Metabotropic Glutamate Receptors Expressed by Microglia in Health and Disease with a Focus on Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:ijms24065240. [PMID: 36982315 PMCID: PMC10048889 DOI: 10.3390/ijms24065240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
Microglia cells are the resident immune cells of the central nervous system. They act as the first-line immune guardians of nervous tissue and central drivers of neuroinflammation. Any homeostatic alteration that can compromise neuron and tissue integrity could activate microglia. Once activated, microglia exhibit highly diverse phenotypes and functions related to either beneficial or harmful consequences. Microglia activation is associated with the release of protective or deleterious cytokines, chemokines, and growth factors that can in turn determine defensive or pathological outcomes. This scenario is complicated by the pathology-related specific phenotypes that microglia can assume, thus leading to the so-called disease-associated microglia phenotypes. Microglia express several receptors that regulate the balance between pro- and anti-inflammatory features, sometimes exerting opposite actions on microglial functions according to specific conditions. In this context, group I metabotropic glutamate receptors (mGluRs) are molecular structures that may contribute to the modulation of the reactive phenotype of microglia cells, and this is worthy of exploration. Here, we summarize the role of group I mGluRs in shaping microglia cells' phenotype in specific physio-pathological conditions, including some neurodegenerative disorders. A significant section of the review is specifically focused on amyotrophic lateral sclerosis (ALS) since it represents an entirely unexplored topic of research in the field.
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Affiliation(s)
- Matilde Balbi
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
| | - Giambattista Bonanno
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Marco Milanese
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
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9
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Guedes JR, Ferreira PA, Costa JM, Cardoso AL, Peça J. Microglia-dependent remodeling of neuronal circuits. J Neurochem 2022; 163:74-93. [PMID: 35950924 PMCID: PMC9826178 DOI: 10.1111/jnc.15689] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 01/11/2023]
Abstract
Microglia are tissue-resident macrophages responsible for the surveillance, neuronal support, and immune defense of the brain parenchyma. Recently, the role played by microglia in the formation and function of neuronal circuits has garnered substantial attention. During development, microglia have been shown to engulf neuronal precursors and participate in pruning mechanisms while, in the mature brain, they influence synaptic signaling, provide trophic support and shape synaptic plasticity. Recently, studies have unveiled different microglial characteristics associated with specific brain regions. This emerging view suggests that the maturation and function of distinct neuronal circuits may be potentially associated with the molecular identity microglia adopts across the brain. Here, we review and summarize the known role of these cells in the thalamus, hippocampus, cortex, and cerebellum. We focus on in vivo studies to highlight the characteristics of microglia that may be important in the remodeling of these neuronal circuits and in relation to neurodevelopmental and neuropsychiatric disorders.
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Affiliation(s)
- Joana R. Guedes
- CNC—Center for Neuroscience and Cell BiologyUniversity of CoimbraCoimbraPortugal,Institute of Interdisciplinary Research (IIIUC), University of CoimbraCoimbraPortugal
| | - Pedro A. Ferreira
- CNC—Center for Neuroscience and Cell BiologyUniversity of CoimbraCoimbraPortugal,Department of Life SciencesUniversity of CoimbraCoimbraPortugal
| | - Jéssica M. Costa
- CNC—Center for Neuroscience and Cell BiologyUniversity of CoimbraCoimbraPortugal,Institute of Interdisciplinary Research (IIIUC), University of CoimbraCoimbraPortugal
| | - Ana L. Cardoso
- CNC—Center for Neuroscience and Cell BiologyUniversity of CoimbraCoimbraPortugal,Institute of Interdisciplinary Research (IIIUC), University of CoimbraCoimbraPortugal
| | - João Peça
- CNC—Center for Neuroscience and Cell BiologyUniversity of CoimbraCoimbraPortugal,Department of Life SciencesUniversity of CoimbraCoimbraPortugal
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10
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Abstract
In mammals, the selective transformation of transient experience into stored memory occurs in the hippocampus, which develops representations of specific events in the context in which they occur. In this review, we focus on the development of hippocampal circuits and the self-organized dynamics embedded within them since the latter critically support the role of the hippocampus in learning and memory. We first discuss evidence that adult hippocampal cells and circuits are sculpted by development as early as during embryonic neurogenesis. We argue that these primary developmental programs provide a scaffold onto which later experience of the external world can be grafted. Next, we review the different sequences in the development of hippocampal cells and circuits at anatomical and functional levels. We cover a period extending from neurogenesis and migration to the appearance of phenotypic diversity within hippocampal cells, and their wiring into functional networks. We describe the progressive emergence of network dynamics in the hippocampus, from sensorimotor-driven early sharp waves to sequences of place cells tracking relational information. We outline the critical turn points and discontinuities in that developmental journey, and close by formulating open questions. We propose that rewinding the process of hippocampal development helps understand the main organization principles of memory circuits.
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Affiliation(s)
- Rosa Cossart
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France
| | - Rustem Khazipov
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France.,Laboratory of Neurobiology, Kazan Federal University, Kazan Russia
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11
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Sharma K, Bisht K, Eyo UB. A Comparative Biology of Microglia Across Species. Front Cell Dev Biol 2021; 9:652748. [PMID: 33869210 PMCID: PMC8047420 DOI: 10.3389/fcell.2021.652748] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/10/2021] [Indexed: 12/26/2022] Open
Abstract
Microglia are unique brain-resident, myeloid cells. They have received growing interest for their implication in an increasing number of neurodevelopmental, acute injury, and neurodegenerative disorders of the central nervous system (CNS). Fate-mapping studies establish microglial ontogeny from the periphery during development, while recent transcriptomic studies highlight microglial identity as distinct from other CNS cells and peripheral myeloid cells. This evidence for a unique microglial ontogeny and identity raises questions regarding their identity and functions across species. This review will examine the available evidence for microglia in invertebrate and vertebrate species to clarify similarities and differences in microglial identity, ontogeny, and physiology across species. This discussion highlights conserved and divergent microglial properties through evolution. Finally, we suggest several interesting research directions from an evolutionary perspective to adequately understand the significance of microglia emergence. A proper appreciation of microglia from this perspective could inform the development of specific therapies geared at targeting microglia in various pathologies.
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Affiliation(s)
- Kaushik Sharma
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, United States.,Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
| | - Kanchan Bisht
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, United States.,Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
| | - Ukpong B Eyo
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, United States.,Department of Neuroscience, University of Virginia, Charlottesville, VA, United States
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12
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Andoh M, Koyama R. Assessing Microglial Dynamics by Live Imaging. Front Immunol 2021; 12:617564. [PMID: 33763064 PMCID: PMC7982483 DOI: 10.3389/fimmu.2021.617564] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/16/2021] [Indexed: 12/13/2022] Open
Abstract
Microglia are highly dynamic in the brain in terms of their ability to migrate, proliferate, and phagocytose over the course of an individual's life. Real-time imaging is a useful tool to examine how microglial behavior is regulated and how it affects the surrounding environment. However, microglia are sensitive to environmental stimuli, so they possibly change their state during live imaging in vivo, mainly due to surgical damage, and in vitro due to various effects associated with culture conditions. Therefore, it is difficult to perform live imaging without compromising the properties of the microglia under physiological conditions. To overcome this barrier, various experimental conditions have been developed; recently, it has become possible to perform live imaging of so-called surveillant microglia in vivo, ex vivo, and in vitro, although there are various limitations. Now, we can choose in vivo, ex vivo, or in vitro live imaging systems according to the research objective. In this review, we discuss the advantages and disadvantages of each experimental system and outline the physiological significance and molecular mechanisms of microglial behavior that have been elucidated by live imaging.
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Affiliation(s)
- Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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13
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Ambrose N, Rodriguez M, Waters KA, Machaalani R. Microglia in the human infant brain and factors that affect expression. Brain Behav Immun Health 2020; 7:100117. [PMID: 34589874 PMCID: PMC8474518 DOI: 10.1016/j.bbih.2020.100117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/21/2022] Open
Abstract
The present study reports on the microglial populations present in 34 regions of the human infant brain (1-11 months), and whether developmental parameters or extrinsic factors such as cigarette smoke exposure, prone sleeping and an upper respiratory tract infection (URTI) influence their expression. Further, we compare microglia populations amongst three sudden unexpected death in infancy (SUDI) sub-groups: explained SUDI (eSUDI, n = 7), sudden infant death syndrome (SIDS) I (n = 8) and SIDS II (n = 13). Ionised calcium binding adaptor molecule-1 (Iba1) was used to determine the morphology and area covered by microglia in a given brain region. Activation was explored using cluster-of-differentiation factor 68 (CD68) and human leukocyte antigen-DP,DQ,DR (HLA). We found regional heterogeneity in the area covered and activation status of microglia across the infant brain. The hippocampus, basal ganglia, white matter and dentate nucleus of the cerebellum showed larger areas of Iba1, while the brainstem had the smallest. Microglia in regions of the basal ganglia and cortex demonstrated positive correlations with infant developmental parameters, while in nuclei of the rostral medulla, negative correlations between microglia parameters were seen. URTI and cigarette smoke exposure were associated with a reduced microglial area in regions of the hippocampus and cortex (parietal and occipital), respectively. In the context of SIDS, a reduced microglial area was seen in SIDS II and fewer SIDS I infants demonstrated activated phenotypes in the hippocampus. Overall, we identify the distribution of microglia in the infant brain to be heterogenous, and influenced by intrinsic and extrinsic factors, and that the SIDS I group is a useful control group for future research into other infant CNS pathologies.
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Affiliation(s)
- Natalie Ambrose
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Michael Rodriguez
- Department of Pathology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Karen A. Waters
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
- Discipline of Child and Adolescent Health, Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Rita Machaalani
- Discipline of Medicine, Central Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
- Discipline of Child and Adolescent Health, Children’s Hospital at Westmead Clinical School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
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14
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Maksoud MJE, Tellios V, Xiang YY, Lu WY. Nitric oxide signaling inhibits microglia proliferation by activation of protein kinase-G. Nitric Oxide 2019; 94:125-134. [PMID: 31759970 DOI: 10.1016/j.niox.2019.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 02/06/2023]
Abstract
Microglia population is primarily determined by a finely-regulated proliferation process during early development of the central nervous system (CNS). Nitric oxide (NO) is known to inhibit proliferation in numerous cell types. However, how NO signaling regulates microglia proliferation remains elusive. Using wildtype (WT) and inducible nitric oxide synthase knockout (iNOS-/-) mice, this study investigated the role and underlying mechanisms of iNOS/NO signaling in microglia proliferation. Here we reported that iNOS-/- mice displayed significantly more BrdU-labeled proliferating microglia in the cortex than that in WT mice at postnatal day 10. Compared to microglia isolated from WT mouse cortex, significantly more iNOS-/- microglia displayed the specific cell-cycle markers Ki67 and phospho-histone H3 (pH3) in their nuclei. In addition, treating WT microglia with the NOS inhibitor LNAME drastically increased the percentage of cells expressing Ki67 and pH3, whereas treating iNOS-/- microglia with NOC18, a slow-release NO-donor, significantly decreased the percentage of microglia expressing the two cell-cycle markers. Moreover, inhibition of protein kinase-G (PKG) in WT microglia increased the proportion of microglia expressing Ki67 and pH3, whereas activation of PKG signaling using 8Br-cGMP in iNOS-/- microglia significantly decreased the fraction of microglia displaying Ki67 and pH3. Interestingly, in the presence of a PKG inhibitor, NOC18 increased the quantity of iNOS-/- microglia expressing Ki67 and pH3. Together, these results indicate that basal activity of iNOS/NO signaling impedes microglial cell-cycle progression and attenuates proliferation through activation of the cGMP-PKG pathway. However, NO increases microglia cell-cycle progression in the absence of cGMP-PKG signaling.
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Affiliation(s)
- Matthew J E Maksoud
- Graduate Program of Neuroscience, The University of Western Ontario, Canada; Robarts Research Institute, The University of Western Ontario, Canada.
| | - Vasiliki Tellios
- Graduate Program of Neuroscience, The University of Western Ontario, Canada; Robarts Research Institute, The University of Western Ontario, Canada.
| | - Yun-Yan Xiang
- Robarts Research Institute, The University of Western Ontario, Canada.
| | - Wei-Yang Lu
- Graduate Program of Neuroscience, The University of Western Ontario, Canada; Robarts Research Institute, The University of Western Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, Canada.
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15
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VanRyzin JW, Marquardt AE, Pickett LA, McCarthy MM. Microglia and sexual differentiation of the developing brain: A focus on extrinsic factors. Glia 2019; 68:1100-1113. [PMID: 31691400 DOI: 10.1002/glia.23740] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 12/16/2022]
Abstract
Microglia, the innate immune cells of the brain, have recently been removed from the position of mere sentinels and promoted to the role of active sculptors of developing circuits and cells. Alongside their functions in normal brain development, microglia coordinate sexual differentiation of the brain, a set of processes which vary by region and endpoint like that of microglia function itself. In this review, we highlight the ways microglia are both targets and drivers of brain sexual differentiation. We examine the factors that may drive sex differences in microglia, with a special focus on how changing microenvironments in the developing brain dictate microglia phenotypes and discuss how their diverse functions sculpt lasting sex-specific changes in the brain. Finally, we consider how sex-specific early life environments contribute to epigenetic programming and lasting sex differences in microglia identity.
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Affiliation(s)
- Jonathan W VanRyzin
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Ashley E Marquardt
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lindsay A Pickett
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland
| | - Margaret M McCarthy
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland
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16
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Eyo UB, Mo M, Yi MH, Murugan M, Liu J, Yarlagadda R, Margolis DJ, Xu P, Wu LJ. P2Y12R-Dependent Translocation Mechanisms Gate the Changing Microglial Landscape. Cell Rep 2019; 23:959-966. [PMID: 29694903 PMCID: PMC5965271 DOI: 10.1016/j.celrep.2018.04.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/21/2018] [Accepted: 03/30/2018] [Indexed: 01/01/2023] Open
Abstract
Microglia are an exquisitely tiled and self-contained population in the CNS that do not receive contributions from circulating monocytes in the periphery. While microglia are long-lived cells, the extent to which their cell bodies are fixed and the molecular mechanisms by which the microglial landscape is regulated have not been determined. Using chronic in vivo two-photon imaging to follow the microglial population in young adult mice, we document a daily rearrangement of the microglial landscape. Furthermore, we show that the microglial landscape can be modulated by severe seizures, acute injury, and sensory deprivation. Finally, we demonstrate a critical role for microglial P2Y12Rs in regulating the microglial landscape through cellular translocation independent of proliferation. These findings suggest that microglial patrol the CNS through both process motility and soma translocation.
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Affiliation(s)
- Ukpong B Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Mingshu Mo
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA; Department of Neurology, First Affiliated Hospital of Guangzhou Medical University, Guangdong 510120, China
| | - Min-Hee Yi
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Madhuvika Murugan
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Junting Liu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Rohan Yarlagadda
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - David J Margolis
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Pingyi Xu
- Department of Neurology, First Affiliated Hospital of Guangzhou Medical University, Guangdong 510120, China.
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
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17
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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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18
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Uweru JO, Eyo UB. A decade of diverse microglial-neuronal physical interactions in the brain (2008-2018). Neurosci Lett 2019; 698:33-38. [PMID: 30625349 PMCID: PMC6435396 DOI: 10.1016/j.neulet.2019.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/29/2018] [Accepted: 01/01/2019] [Indexed: 12/17/2022]
Abstract
Microglia are unique cells of the central nervous system (CNS) with a distinct ontogeny and molecular profile. They are the predominant immune resident cell in the CNS. Recent studies have revealed a diversity of transient and terminal physical interactions between microglia and neurons in the vertebrate brain. In this review, we follow the historical trail of the discovery of these interactions, summarize their notable features, provide implications of these discoveries to CNS function, emphasize emerging themes along the way and peak into the future of what outstanding questions remain to move the field forward.
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Affiliation(s)
- Joseph O Uweru
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, United States; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, United States
| | - Ukpong B Eyo
- Department of Neuroscience, University of Virginia, Charlottesville, VA, United States; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, United States; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, United States.
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19
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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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20
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Zhao X, Eyo UB, Murguan M, Wu LJ. Microglial interactions with the neurovascular system in physiology and pathology. Dev Neurobiol 2018; 78:604-617. [PMID: 29318762 PMCID: PMC5980686 DOI: 10.1002/dneu.22576] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/01/2018] [Accepted: 01/06/2018] [Indexed: 01/11/2023]
Abstract
Microglia as immune cells of the central nervous system (CNS) play significant roles not only in pathology but also in physiology, such as shaping of the CNS during development and its proper maintenance in maturity. Emerging research is showing a close association between microglia and the neurovasculature that is critical for brain energy supply. In this review, we summarize the current literature on microglial interaction with the vascular system in the normal and diseased brain. First, we highlight data that indicate interesting potential involvement of microglia in developmental angiogenesis. Then we discuss the evidence for microglial participation with the vasculature in neuropathologies from brain tumors to acute injuries such as ischemic stroke to chronic neurodegenerative conditions. We conclude by suggesting future areas of research to advance the field in light of current technical progress and outstanding questions. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 604-617, 2018.
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Affiliation(s)
- Xiaoliang Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
| | - Ukpong B. Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Madhuvika Murguan
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
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21
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VanRyzin JW, Pickett LA, McCarthy MM. Microglia: Driving critical periods and sexual differentiation of the brain. Dev Neurobiol 2018; 78:580-592. [PMID: 29243403 DOI: 10.1002/dneu.22569] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 12/05/2017] [Accepted: 12/13/2017] [Indexed: 12/12/2022]
Abstract
The proverbial role of microglia during brain development is shifting from passive members of the brain's immune system to active participants that are able to dictate enduring outcomes. Despite these advances, little attention has been paid to one of the most critical components of early brain development-sexual differentiation. Mounting evidence suggests that the normal developmental functions microglia perform-cell number regulation and synaptic connectivity-may be involved in the sex-specific patterning of the brain during these early sensitive periods, and may have lasting sex-dependent and sex-independent effects on behavior. In this review, we outline the known functions of microglia during developmental sensitive periods, and highlight the role they play in the establishment of sex differences in brain and behavior. We also propose a framework for how researchers can incorporate microglia in their study of sex differences and vice versa. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 580-592, 2018.
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Affiliation(s)
- Jonathan W VanRyzin
- Department of Pharmacology, The University of Maryland School of Medicine, Baltimore, Maryland, 21201.,Program in Neuroscience, The University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - Lindsay A Pickett
- Department of Pharmacology, The University of Maryland School of Medicine, Baltimore, Maryland, 21201.,Program in Neuroscience, The University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - Margaret M McCarthy
- Department of Pharmacology, The University of Maryland School of Medicine, Baltimore, Maryland, 21201.,Program in Neuroscience, The University of Maryland School of Medicine, Baltimore, Maryland, 21201
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22
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Paris I, Savage JC, Escobar L, Abiega O, Gagnon S, Hui CW, Tremblay MÈ, Sierra A, Valero J. ProMoIJ: A new tool for automatic three-dimensional analysis of microglial process motility. Glia 2017; 66:828-845. [PMID: 29288586 DOI: 10.1002/glia.23287] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/28/2017] [Accepted: 12/11/2017] [Indexed: 12/31/2022]
Abstract
Microglia, the immune cells of the central nervous system, continuously survey the brain to detect alterations and maintain tissue homeostasis. The motility of microglial processes is indicative of their surveying capacity in normal and pathological conditions. The gold standard technique to study motility involves the use of two-photon microscopy to obtain time-lapse images from brain slices or the cortex of living animals. This technique generates four dimensionally-coded images which are analyzed manually using time-consuming, non-standardized protocols. Microglial process motility analysis is frequently performed using Z-stack projections with the consequent loss of three-dimensional (3D) information. To overcome these limitations, we developed ProMoIJ, a pack of ImageJ macros that perform automatic motility analysis of cellular processes in 3D. The main core of ProMoIJ is formed by two macros that assist the selection of processes, automatically reconstruct their 3D skeleton, and analyze their motility (process and tip velocity). Our results show that ProMoIJ presents several key advantages compared with conventional manual analysis: (1) reduces the time required for analysis, (2) is less sensitive to experimenter bias, and (3) is more robust to varying numbers of processes analyzed. In addition, we used ProMoIJ to demonstrate that commonly performed 2D analysis underestimates microglial process motility, to reveal that only cells adjacent to a laser injured area extend their processes toward the lesion site, and to demonstrate that systemic inflammation reduces microglial process motility. ProMoIJ is a novel, open-source, freely-available tool which standardizes and accelerates the time-consuming labor of 3D analysis of microglial process motility.
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Affiliation(s)
- Iñaki Paris
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Bizkaia, Spain
| | - Julie C Savage
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada.,Département de médecine moléculaire, Université Laval, Québec, Canada
| | - Laura Escobar
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Bizkaia, Spain
| | - Oihane Abiega
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Bizkaia, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Bizkaia, Spain
| | - Steven Gagnon
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada.,Département de médecine moléculaire, Université Laval, Québec, Canada
| | - Chin-Wai Hui
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada.,Département de médecine moléculaire, Université Laval, Québec, Canada
| | - Marie-Ève Tremblay
- Centre de recherche du CHU de Québec, Axe Neurosciences, Québec, Canada.,Département de médecine moléculaire, Université Laval, Québec, Canada
| | - Amanda Sierra
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Bizkaia, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Bizkaia, Spain.,University of the Basque Country, Leioa, Bizkaia, Spain
| | - Jorge Valero
- Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Bizkaia, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Bizkaia, Spain
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23
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Fernández-Arjona MDM, Grondona JM, Granados-Durán P, Fernández-Llebrez P, López-Ávalos MD. Microglia Morphological Categorization in a Rat Model of Neuroinflammation by Hierarchical Cluster and Principal Components Analysis. Front Cell Neurosci 2017; 11:235. [PMID: 28848398 PMCID: PMC5550745 DOI: 10.3389/fncel.2017.00235] [Citation(s) in RCA: 236] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/25/2017] [Indexed: 12/24/2022] Open
Abstract
It is known that microglia morphology and function are closely related, but only few studies have objectively described different morphological subtypes. To address this issue, morphological parameters of microglial cells were analyzed in a rat model of aseptic neuroinflammation. After the injection of a single dose of the enzyme neuraminidase (NA) within the lateral ventricle (LV) an acute inflammatory process occurs. Sections from NA-injected animals and sham controls were immunolabeled with the microglial marker IBA1, which highlights ramifications and features of the cell shape. Using images obtained by section scanning, individual microglial cells were sampled from various regions (septofimbrial nucleus, hippocampus and hypothalamus) at different times post-injection (2, 4 and 12 h). Each cell yielded a set of 15 morphological parameters by means of image analysis software. Five initial parameters (including fractal measures) were statistically different in cells from NA-injected rats (most of them IL-1β positive, i.e., M1-state) compared to those from control animals (none of them IL-1β positive, i.e., surveillant state). However, additional multimodal parameters were revealed more suitable for hierarchical cluster analysis (HCA). This method pointed out the classification of microglia population in four clusters. Furthermore, a linear discriminant analysis (LDA) suggested three specific parameters to objectively classify any microglia by a decision tree. In addition, a principal components analysis (PCA) revealed two extra valuable variables that allowed to further classifying microglia in a total of eight sub-clusters or types. The spatio-temporal distribution of these different morphotypes in our rat inflammation model allowed to relate specific morphotypes with microglial activation status and brain location. An objective method for microglia classification based on morphological parameters is proposed. Main pointsMicroglia undergo a quantifiable morphological change upon neuraminidase induced inflammation. Hierarchical cluster and principal components analysis allow morphological classification of microglia. Brain location of microglia is a relevant factor.
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Affiliation(s)
- María Del Mar Fernández-Arjona
- Departamento de Biología Celular, Facultad de Ciencias, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de MálagaMálaga, Spain
| | - Jesús M Grondona
- Departamento de Biología Celular, Facultad de Ciencias, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de MálagaMálaga, Spain
| | - Pablo Granados-Durán
- Departamento de Biología Celular, Facultad de Ciencias, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de MálagaMálaga, Spain
| | - Pedro Fernández-Llebrez
- Departamento de Biología Celular, Facultad de Ciencias, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de MálagaMálaga, Spain
| | - María D López-Ávalos
- Departamento de Biología Celular, Facultad de Ciencias, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de MálagaMálaga, Spain
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24
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Nelson LH, Warden S, Lenz KM. Sex differences in microglial phagocytosis in the neonatal hippocampus. Brain Behav Immun 2017; 64:11-22. [PMID: 28341582 PMCID: PMC5512447 DOI: 10.1016/j.bbi.2017.03.010] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/07/2017] [Accepted: 03/20/2017] [Indexed: 12/12/2022] Open
Abstract
Microglia regulate brain development through many processes, such as promoting neurogenesis, supporting cell survival, and phagocytizing progenitor, newly-born, and dying cells. Many of these same developmental processes show robust sex differences, yet very few studies have assessed sex differences in microglia function during development. Hormonally-induced sexual differentiation of the brain occurs during the perinatal period, thus we examined sex differences in microglial morphology, phagocytosis, and proliferation in the hippocampus during the early postnatal period. We found that the neonatal female hippocampus had significantly more microglia with phagocytic cups than the male hippocampus. We subsequently found that female microglia phagocytized more neural progenitor cells and healthy cells compared to males, but there were no sex differences in the number of newly-born or dying cells targeted by microglial phagocytosis. We found that the number of phagocytic microglia in females was reduced to male-typical levels by treatment with estradiol, the hormone responsible for masculinizing the rodent brain. Females also had higher expression of several phagocytic pathway genes in the hippocampus compared to males. In contrast to robust sex differences in phagocytic microglia, we found no sex differences in the number of microglia with amoeboid, transitioning, or ramified morphologies or differences in three-dimensional reconstructions of microglial morphology. While we did not find a baseline sex difference in microglial proliferation during or following the prenatal gonadal hormone surge in males, we found that estradiol treatment increased microglia proliferation in females. Overall, these data show that there are important sex differences in microglia function in the hippocampus during the early neonatal period.
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Affiliation(s)
- Lars H Nelson
- Department of Neuroscience, The Ohio State University, 333 W. 10th Ave., Columbus, OH 43210, USA; Group in Behavioral Neuroendocrinology, The Ohio State University, Columbus OH, USA.
| | - Spencer Warden
- Department of Psychology, The Ohio State University, 1835 Neil Ave, Columbus, OH 43210,Group in Behavioral Neuroendocrinology, The Ohio State University, Columbus OH
| | - Kathryn M Lenz
- Department of Neuroscience, The Ohio State University, 333 W. 10th Ave., Columbus, OH 43210, USA; Department of Psychology, The Ohio State University, 1835 Neil Ave, Columbus, OH 43210, USA; Group in Behavioral Neuroendocrinology, The Ohio State University, Columbus OH, USA.
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25
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Martín-Estebané M, Navascués J, Sierra-Martín A, Martín-Guerrero SM, Cuadros MA, Carrasco MC, Marín-Teva JL. Onset of microglial entry into developing quail retina coincides with increased expression of active caspase-3 and is mediated by extracellular ATP and UDP. PLoS One 2017; 12:e0182450. [PMID: 28763502 PMCID: PMC5538646 DOI: 10.1371/journal.pone.0182450] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 07/18/2017] [Indexed: 12/31/2022] Open
Abstract
Microglial cell precursors located in the area of the base of the pecten and the optic nerve head (BP/ONH) start to enter the retina of quail embryos at the 7th day of incubation (E7), subsequently colonizing the entire retina by central-to-peripheral tangential migration, as previously shown by our group. The present study demonstrates a precise chronological coincidence of the onset of microglial cell entry into the retina with a striking increase in death of retinal cells, as revealed by their active caspase-3 expression and TUNEL staining, in regions dorsal to the BP/ONH area, suggesting that dying retinal cells would contribute to the microglial cell inflow into the retina. However, the molecular mechanisms involved in this inflow are currently unclear. Extracellular nucleotides, such as ATP and UDP, have previously been shown to favor migration of microglia towards brain injuries because they are released by apoptotic cells and stimulate both chemotaxis and chemokinesis in microglial cells via signaling through purinergic receptors. Hence, we tested here the hypothesis that ATP and UDP play a role in the entry and migration of microglial precursors into the developing retina. For this purpose, we used an experimental model system based on organotypic cultures of E6.5 quail embryo retina explants, which mimics the entry and migration of microglial precursors in the in situ developing retina. Inhibition of purinergic signaling by treating retina explants with either apyrase, a nucleotide-hydrolyzing enzyme, or suramin, a broad spectrum antagonist of purinergic receptors, significantly prevents the entry of microglial cells into the retina. In addition, treatment of retina explants with either exogenous ATP or UDP results in significantly increased numbers of microglial cells entering the retina. In light of these findings, we conclude that purinergic signaling by extracellular ATP and UDP is necessary for the entry and migration of microglial cells into the embryonic retina by inducing chemokinesis in these cells.
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Affiliation(s)
- María Martín-Estebané
- 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
| | - Ana Sierra-Martín
- Departamento de Biología Celular, Fisiología e Inmunología, Facultad de Biociencias, Universidad Autónoma de Barcelona, Bellaterra, Barcelona, Spain
| | | | - Miguel A. Cuadros
- 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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26
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Smolders SMT, Swinnen N, Kessels S, Arnauts K, Smolders S, Le Bras B, Rigo JM, Legendre P, Brône B. Age-specific function of α5β1 integrin in microglial migration during early colonization of the developing mouse cortex. Glia 2017; 65:1072-1088. [PMID: 28417486 DOI: 10.1002/glia.23145] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/10/2017] [Accepted: 03/14/2017] [Indexed: 12/31/2022]
Abstract
Microglia, the immune cells of the central nervous system, take part in brain development and homeostasis. They derive from primitive myeloid progenitors that originate in the yolk sac and colonize the brain mainly through intensive migration. During development, microglial migration speed declines which suggests that their interaction with the microenvironment changes. However, the matrix-cell interactions allowing dispersion within the parenchyma are unknown. Therefore, we aimed to better characterize the migration behavior and to assess the role of matrix-integrin interactions during microglial migration in the embryonic brain ex vivo. We focused on microglia-fibronectin interactions mediated through the fibronectin receptor α5β1 integrin because in vitro work indirectly suggested a role for this ligand-receptor pair. Using 2-photon time-lapse microscopy on acute ex vivo embryonic brain slices, we found that migration occurs in a saltatory pattern and is developmentally regulated. Most importantly, there is an age-specific function of the α5β1 integrin during microglial cortex colonization. At embryonic day (E) 13.5, α5β1 facilitates migration while from E15.5, it inhibits migration. These results indicate a developmentally regulated function of α5β1 integrin in microglial migration during colonization of the embryonic brain.
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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
| | | | | | | | - Silke Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium.,Laboratory of Neuronal Differentiation, VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Barbara Le Bras
- 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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27
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Mosser CA, Baptista S, Arnoux I, Audinat E. Microglia in CNS development: Shaping the brain for the future. Prog Neurobiol 2017; 149-150:1-20. [DOI: 10.1016/j.pneurobio.2017.01.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/22/2022]
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28
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Wang Y, Fang W, Wu L, Yao X, Wu S, Wang J, Xu Z, Tian F, He Z, Dong B. Neuroprotective effect of picroside II in brain injury in mice. Am J Transl Res 2016; 8:5532-5544. [PMID: 28078024 PMCID: PMC5209504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 12/04/2016] [Indexed: 06/06/2023]
Abstract
Various types of brain injury which led to the damage of brain tissue structure and neurological dysfunction continues to be the major causes of disability and mortality. Picroside II (PII) possesses a wide range of pharmacological effects and has been proved to ameliorate ischemia and reperfusion injury of kidney and brain. However, critical questions remain about other brain injuries. We investigated the protective effect of PII in four well-characterized murine models of brain injury. Models showed a subsequent regional inflammatory response and oxidative stress in common, which might be improved by the administration of PII (20 mg/kg). Meanwhile, a series of morphological and histological analyses for reinforcement was performed. In traumatic, ischemic and infectious induced injuries, it was observed that the survival rate, apoptosis related proteins, Caspase-3, and the expression of acute inflammatory cytokines (IL-1β, IL-6 and TNF-α) were significantly alleviated after PII injection, but PII treatment alone showed no effect on them as well. The western blot results indicated that TLR4 and NF-κB were clearly downregulated with PII administration. In conclusion, our results suggested that PII with a recommended concentration of 20 mg/kg could provide neuroprotective effects against multi-cerebral injuries in mice by suppressing the over-reactive inflammatory responses and oxidative stress and attenuating the damage of brain tissue for further neurological recovery.
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Affiliation(s)
- Yida Wang
- Department of Neurosurgery, The First Affiliated Hospital of Dalian Medical UniversityDalian, China
| | - Wei Fang
- Department of Medicine, Hebei North UniversityZhangjiakou, Hebei, China
| | - Liang Wu
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical UniversityXuzhou, China
| | - Xueya Yao
- Department of Medicine, Hebei North UniversityZhangjiakou, Hebei, China
| | - Suzhen Wu
- Department of Anesthesiology, Ningxiang People’s Hospital of Hunan ProvinceNingxiang, Hunan, China
| | - Jie Wang
- Department of Neurosurgery, The First Affiliated Hospital of Dalian Medical UniversityDalian, China
| | - Zhen Xu
- Department of Neurosurgery, The First Affiliated Hospital of Dalian Medical UniversityDalian, China
| | - Fubo Tian
- Department of Anesthesiology, Shanghai Obstetrics and Gynecology Hospital, Fudan UniversityShanghai, China
| | - Zhenzhou He
- Department of Anesthesiology and ICU, South Campus, Renji Hospital School of Medicine, Shanghai Jiao Tong UniversityChina
| | - Bin Dong
- Department of Neurosurgery, The First Affiliated Hospital of Dalian Medical UniversityDalian, China
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29
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Rohan Walker F, Yirmiya R. Microglia, physiology and behavior: A brief commentary. Brain Behav Immun 2016; 55:1-5. [PMID: 26975889 DOI: 10.1016/j.bbi.2016.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 03/10/2016] [Indexed: 01/21/2023] Open
Affiliation(s)
- F Rohan Walker
- School of Biomedical Sciences and Newcastle, University of Newcastle, Australia; Department of Psychology, The Hebrew University of Jerusalem, Israel
| | - Raz Yirmiya
- School of Biomedical Sciences and Newcastle, University of Newcastle, Australia; Department of Psychology, The Hebrew University of Jerusalem, Israel.
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