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Nevelchuk S, Brawek B, Schwarz N, Valiente-Gabioud A, Wuttke TV, Kovalchuk Y, Koch H, Höllig A, Steiner F, Figarella K, Griesbeck O, Garaschuk O. Morphotype-specific calcium signaling in human microglia. J Neuroinflammation 2024; 21:175. [PMID: 39020359 PMCID: PMC11256502 DOI: 10.1186/s12974-024-03169-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
BACKGROUND Key functions of Ca2+ signaling in rodent microglia include monitoring the brain state as well as the surrounding neuronal activity and sensing the danger or damage in their vicinity. Microglial Ca2+ dyshomeostasis is a disease hallmark in many mouse models of neurological disorders but the Ca2+ signal properties of human microglia remain unknown. METHODS We developed a novel genetically-encoded ratiometric Ca2+ indicator, targeting microglial cells in the freshly resected human tissue, organotypically cultured tissue slices and analyzed in situ ongoing Ca2+ signaling of decades-old microglia dwelling in their native microenvironment. RESULTS The data revealed marked compartmentalization of Ca2+ signals, with signal properties differing across the compartments and resident morphotypes. The basal Ca2+ levels were low in ramified and high in ameboid microglia. The fraction of cells with ongoing Ca2+ signaling, the fraction and the amplitude of process Ca2+ signals and the duration of somatic Ca2+ signals decreased when moving from ramified via hypertrophic to ameboid microglia. In contrast, the size of active compartments, the fraction and amplitude of somatic Ca2+ signals and the duration of process Ca2+ signals increased along this pathway.
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Affiliation(s)
- Sofia Nevelchuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ariel Valiente-Gabioud
- Tools for Bio-Imaging, Max-Planck-Institute for Biological Intelligence, Martinsried, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Yury Kovalchuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Henner Koch
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Anke Höllig
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
| | - Frederik Steiner
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Katherine Figarella
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Oliver Griesbeck
- Tools for Bio-Imaging, Max-Planck-Institute for Biological Intelligence, Martinsried, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany.
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2
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Han PC, Baker TG. Glial and glioneuronal tumors: Navigating the complexity of evolving concepts and new classification. J Neurol Sci 2024; 461:123058. [PMID: 38781807 DOI: 10.1016/j.jns.2024.123058] [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: 02/26/2024] [Revised: 04/25/2024] [Accepted: 05/18/2024] [Indexed: 05/25/2024]
Abstract
The World Health Organization (WHO) published the 5th edition classification of tumors of central nervous system in 2021, commonly abbreviated as WHO CNS5, which became the new standard for brain tumor diagnosis and therapy. This edition dramatically impacted tumor diagnostics. In short it introduced new tumors, changed the names of previously recognized tumors, and modified the working definition of previously known tumors. The new system appears complex due to the integration of morphological and multiple molecular criteria. The most radical changes occurred in the field of glial and glioneuronal tumors, which constitutes the lengthy first chapter of this new edition. Herein we present an illustrative outline of the evolving concepts of glial and glioneuronal tumors. We also attempt to explain the rationales behind this substantial change in tumor classification and the challenges to update and integrate it into clinical practice. We aim to present a concise and precise roadmap to aid navigation through the intricate conceptual framework of glial and glioneuronal tumors in the context of WHO CNS5.
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Affiliation(s)
- Peng Cheng Han
- Department of Pathology, Anatomy and Laboratory Medicine, Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America.
| | - Tiffany G Baker
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, United States of America
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3
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Tremblay MÈ, Verkhratsky A. General Pathophysiology of Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:3-14. [PMID: 39207683 DOI: 10.1007/978-3-031-55529-9_1] [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, which are the resident innate immune cells of the central nervous system (CNS), have emerged as critical for maintaining health by not only ensuring proper development, activity, and plasticity of neurones and glial cells but also maintaining and restoring homeostasis when faced with various challenges across the lifespan. This chapter is dedicated to the current understanding of microglia, including their beneficial versus detrimental roles, which are highly complex, rely on various microglial states, and intimately depend on their spatiotemporal context. Microglia are first contextualized within the perspective of finding therapeutic strategies to cure diseases in the twenty-first century-the overall functions of neuroglia with relation one to another and to neurones, and their shared CNS environment. A historical framework is provided, and the main principles of glial neuropathology are enunciated. The current view of microglial nomenclature is then covered, notably by discussing the rejected concepts of microglial activation, their polarisation into M1 and M2 phenotypes, and neuroinflammation. The transformation of the microglial population through the addition, migration, and elimination of individual members, as well as their dynamic metamorphosis between a wide variety of structural and functional states, based on the experienced physiological and pathological stimuli, is subsequently discussed. Lastly, the perspective of microglia as a cell type endowed with a health status determining their outcomes on adaptive CNS plasticity as well as disease pathology is proposed for twenty-first-century approaches to disease prevention and treatment.
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Affiliation(s)
- Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, Canada.
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec City, QC, Canada.
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada.
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, Vancouver, BC, Canada.
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK.
- Department of Neurosciences,University of the Basque Country,, Leioa, Spain.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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4
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Augusto-Oliveira M, Tremblay MÈ, Verkhratsky A. Receptors on Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:83-121. [PMID: 39207688 DOI: 10.1007/978-3-031-55529-9_6] [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
Microglial cells are the most receptive cells in the central nervous system (CNS), expressing several classes of receptors reflecting their immune heritage and newly acquired neural specialisation. Microglia possess, depending on the particular context, receptors to neurotransmitters and neuromodulators as well as immunocompetent receptors. This rich complement allows microglial cells to monitor the functional status of the nervous system, contribute actively to the regulation of neural activity and plasticity and homeostasis, and guard against pathogens as well as other challenges to the CNS's integrity and function.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
- Programa de Pós-Graduação em Farmacologia e Bioquímica, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, Canada
- Axe neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, Vancouver, BC, Canada
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK.
- Department of Neurosciences, University of the Basque Country, Leioa, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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5
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Garaschuk O, Verkhratsky A. Calcium Signalling in Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:123-133. [PMID: 39207689 DOI: 10.1007/978-3-031-55529-9_7] [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
Intracellular Ca2+ signalling represents the substrate of microglial excitability. Spatially and temporally organised changes in the free cytoplasmic Ca2+ concentration ([Ca2+]i) are generated in response to physiological and pathological stimuli. Parameters of these intracellular Ca2+ signals are defined by Ca2+ signalling toolkits that may change with age or context therefore increasing adaptive capabilities of microglia. Main Ca2+ signalling pathways in microglial cells are associated with dynamic endoplasmic reticulum Ca2+ stores and with plasmalemmal Ca2+ entry mediated by several sets of Ca2+-permeable channels including transient receptor potential (TRP) channels, ORAI channels and P2X4/7 purinoceptors. Microglial Ca2+ dynamics is also linked to TREM2 signalling cascade, contributing to neuroprotection in neurodegenerative diseases. Microglial Ca2+ signals act as reliable and precise sensors of brain dyshomeostasis and pathological insults.
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Affiliation(s)
- Olga Garaschuk
- Institute of Physiology, Department Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Department of Neurosciences, University of the Basque Country, Leioa, Spain.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Liu Y, Zhang J, Li Y, Zhao Y, Kuermanbayi S, Zhuang J, Zhang H, Xu F, Li F. Matrix stiffness-dependent microglia activation in response to inflammatory cues: in situ investigation by scanning electrochemical microscopy. Chem Sci 2023; 15:171-184. [PMID: 38131065 PMCID: PMC10732011 DOI: 10.1039/d3sc03504b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 11/26/2023] [Indexed: 12/23/2023] Open
Abstract
Microglia play a crucial role in maintaining the homeostasis of the central nervous system (CNS) by sensing and responding to mechanical and inflammatory cues in their microenvironment. However, the interplay between mechanical and inflammatory cues in regulating microglia activation remains elusive. In this work, we constructed in vitro mechanical-inflammatory coupled microenvironment models of microglia by culturing BV2 cells (a murine microglial cell line) on polyacrylamide gels with tunable stiffness and incorporating a lipopolysaccharide (LPS) to mimic the physiological and pathological microenvironment of microglia in the hippocampus. Through characterization of activation-related proteins, cytokines, and reactive oxygen species (ROS) levels, we observed that the LPS treatment induced microglia on a stiff matrix to exhibit overexpression of NOX2, higher levels of ROS and inflammatory factors compared to those on a soft matrix. Additionally, using scanning electrochemical microscopy (SECM), we performed in situ characterization and discovered that microglia on a stiff matrix promoted extracellular ROS production, leading to a disruption in their redox balance and increased susceptibility to LPS-induced ROS production. Furthermore, the respiratory activity and migration behavior of microglia were closely associated with their activation process, with the stiff matrix-LPS-induced microglia demonstrating the most pronounced changes in respiratory activity and migration ability. This work represents the first in situ and dynamic monitoring of microglia activation state alterations under a mechanical-inflammatory coupled microenvironment using SECM. Our findings shed light on matrix stiffness-dependent activation of microglia in response to an inflammatory microenvironment, providing valuable insights into the mechanisms underlying neuroinflammatory processes in the CNS.
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Affiliation(s)
- Yulin Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Junjie Zhang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Yabei Li
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
- School of Chemistry, Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Yuxiang Zhao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Shuake Kuermanbayi
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Jian Zhuang
- Key Laboratory of Education Ministry for Modern Design Rotor-Bearing System, School of Mechanical Engineering, Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Hua Zhang
- Department of Neurosurgery, The First Affiliated Hospital, Xi'an Jiaotong University Xi'an 710061 P. R. China
| | - Feng Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
| | - Fei Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China
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Pan K, Garaschuk O. The role of intracellular calcium-store-mediated calcium signals in in vivo sensor and effector functions of microglia. J Physiol 2023; 601:4203-4215. [PMID: 35315518 DOI: 10.1113/jp279521] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/09/2022] [Indexed: 11/08/2022] Open
Abstract
Under physiological conditions microglia, the immune sentinels of the brain, constantly monitor their microenvironment. In the case of danger, damage or cell/tissue dyshomeostasis, they react with changes in process motility, polarization, directed process movement, morphology and gene expression profile; release pro- and anti-inflammatory mediators; proliferate; and clean brain parenchyma by means of phagocytosis. Based on recent transcriptomic and in vivo Ca2+ imaging data, we argue that the local cell/tissue dyshomeostasis is sensed by microglia via intracellular Ca2+ signals, many of which are mediated by Ca2+ release from the intracellular Ca2+ stores. These signals encode the strength, duration and spatiotemporal pattern of the stimulus and, at the same time, relay this information further to trigger the respective Ca2+ -dependent effector pathways. We also point to the fact that microglial Ca2+ signalling is sexually dimorphic and undergoes profound changes across the organism's lifespan. Interestingly, the first changes in microglial Ca2+ signalling are visible already in 9- to 11-month-old mice, roughly corresponding to 40-year-old humans.
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Affiliation(s)
- Kuang Pan
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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Steardo L, Steardo L, Scuderi C. Astrocytes and the Psychiatric Sequelae of COVID-19: What We Learned from the Pandemic. Neurochem Res 2023; 48:1015-1025. [PMID: 35922744 PMCID: PMC9362636 DOI: 10.1007/s11064-022-03709-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/01/2022] [Accepted: 07/22/2022] [Indexed: 11/05/2022]
Abstract
COVID-19, initially regarded as specific lung disease, exhibits an extremely broad spectrum of symptoms. Extrapulmonary manifestations of the disease also include important neuropsychiatric symptoms with atypical characteristics. Are these disturbances linked to stress accompanying every systemic infection, or are due to specific neurobiological changes associated with COVID-19? Evidence accumulated so far indicates that the pathophysiology of COVID-19 is characterized by systemic inflammation, hypoxia resulting from respiratory failure, and neuroinflammation (either due to viral neurotropism or in response to cytokine storm), all affecting the brain. It is reasonable to hypothesize that all these events may initiate or worsen psychiatric and cognitive disorders. Damage to the brain triggers a specific type of reactive response mounted by neuroglia cells, in particular by astrocytes which are the homeostatic cell par excellence. Astrocytes undergo complex morphological, biochemical, and functional remodeling aimed at mobilizing the regenerative potential of the central nervous system. If the brain is not directly damaged, resolution of systemic pathology usually results in restoration of the physiological homeostatic status of neuroglial cells. The completeness and dynamics of this process in pathological conditions remain largely unknown. In a subset of patients, glial cells could fail to recover after infection thus promoting the onset and progression of COVID-19-related neuropsychiatric diseases. There is evidence from post-mortem examinations of the brains of COVID-19 patients of alterations in both astrocytes and microglia. In conclusion, COVID-19 activates a huge reactive response of glial cells, that physiologically act as the main controller of the inflammatory, protective and regenerative events. However, in some patients the restoration of glial physiological state does not occur, thus compromising glial function and ultimately resulting in homeostatic failure underlying a set of specific neuropsychiatric symptoms related to COVID-19.
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Affiliation(s)
- Luca Steardo
- Psychiatric Unit, Department of Health Sciences, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Luca Steardo
- Department of Physiology and Pharmacology "Vittorio Erspamer", SAPIENZA University of Rome, Rome, Italy
- Università Giustino Fortunato, Benevento, Italy
| | - Caterina Scuderi
- Department of Physiology and Pharmacology "Vittorio Erspamer", SAPIENZA University of Rome, Rome, Italy.
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9
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Drug-induced microglial phagocytosis in multiple sclerosis and experimental autoimmune encephalomyelitis and the underlying mechanisms. Mol Biol Rep 2023; 50:749-759. [PMID: 36309614 DOI: 10.1007/s11033-022-07968-z] [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: 04/11/2022] [Accepted: 09/21/2022] [Indexed: 02/01/2023]
Abstract
Microglia are resident macrophages of the central nervous system (CNS). It plays a significant role in immune surveillance under physiological conditions. On stimulation by pathogens, microglia change their phenotypes, phagocytize toxic molecules, secrete pro-inflammatory/anti-inflammatory factors, promotes tissue repair, and maintain the homeostasis in CNS. Accumulation of myelin debris in multiple sclerosis (MS)/experimental autoimmune encephalomyelitis (EAE) inhibits remyelination by decreasing the phagocytosis by microglia and prevent the recovery of MS/EAE. Drug induced microglia phagocytosis could be a novel therapeutic intervention for the treatment of MS/EAE. But the abnormal phagocytosis of neurons and synapses by activated microglia will lead to neuronal damage and degeneration. It indicates that the phagocytosis of microglia has many beneficial and harmful effects in central neurodegenerative diseases. Therefore, simply promoting or inhibiting the phagocytic activity of microglia may not achieve ideal therapeutic results. However, limited reports are available to elucidate the microglia mediated phagocytosis and its underlying molecular mechanisms. On this basis, the present review describes microglia-mediated phagocytosis, drug-induced microglia phagocytosis, molecular mechanism, and novel approach for MS/EAE treatment.
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10
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Augusto-Oliveira M, Arrifano GP, Delage CI, Tremblay MÈ, Crespo-Lopez ME, Verkhratsky A. Plasticity of microglia. Biol Rev Camb Philos Soc 2021; 97:217-250. [PMID: 34549510 DOI: 10.1111/brv.12797] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Microglial cells are the scions of foetal macrophages which invade the neural tube early during embryogenesis. The nervous tissue environment instigates the phenotypic metamorphosis of foetal macrophages into idiosyncratic surveilling microglia, which are generally characterised by a small cell body and highly ramified motile processes that constantly scan the nervous tissue for signs of changes in homeostasis and allow microglia to perform crucial homeostatic functions. The surveilling microglial phenotype is evolutionarily conserved from early invertebrates to humans. Despite this evolutionary conservation, microglia show substantial heterogeneity in their gene and protein expression, as well as morphological appearance. These differences are age, region and context specific and reflect a high degree of plasticity underlying the life-long adaptation of microglia, supporting the exceptional adaptive capacity of the central nervous system. Microgliocytes are essential elements of cellular network formation and refinement in the developing nervous tissue. Several distinct patrolling modes of microglial processes contribute to the formation, modification, and pruning of synapses; to the support and protection of neurones through microglial-somatic junctions; and to the control of neuronal and axonal excitability by specific microglia-axonal contacts. In pathology, microglia undergo proliferation and reactive remodelling known as microgliosis, which is context dependent, yet represents an evolutionarily conserved defence response. Microgliosis results in the emergence of multiple disease and context-specific reactive states; in addition, neuropathology is associated with the appearance of specific protective or recovery microglial forms. In summary, the plasticity of microglia supports the development and functional activity of healthy nervous tissue and provides highly sophisticated defences against disease.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Charlotte Isabelle Delage
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada.,Neurology and Neurosurgery Department, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.,Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Bureau 4835, 1050 Avenue de la Médecine, Québec City, QC, G1V 0A6, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.,Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania
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11
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Augusto-Oliveira M, Verkhratsky A. Lifestyle-dependent microglial plasticity: training the brain guardians. Biol Direct 2021; 16:12. [PMID: 34353376 PMCID: PMC8340437 DOI: 10.1186/s13062-021-00297-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Lifestyle is one of the most powerful instruments shaping mankind; the lifestyle includes many aspects of interactions with the environment, from nourishment and education to physical activity and quality of sleep. All these factors taken in complex affect neuroplasticity and define brain performance and cognitive longevity. In particular, physical exercise, exposure to enriched environment and dieting act through complex modifications of microglial cells, which change their phenotype and modulate their functional activity thus translating lifestyle events into remodelling of brain homoeostasis and reshaping neural networks ultimately enhancing neuroprotection and cognitive longevity.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal Do Pará, Belém, 66075-110, Brazil.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, 01102, Vilnius, Lithuania. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain. .,Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
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12
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Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
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Lin SS, Tang Y, Illes P, Verkhratsky A. The Safeguarding Microglia: Central Role for P2Y 12 Receptors. Front Pharmacol 2021; 11:627760. [PMID: 33519493 PMCID: PMC7840491 DOI: 10.3389/fphar.2020.627760] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/30/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Si-Si Lin
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- International Collaborative Center on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yong Tang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- International Collaborative Center on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Peter Illes
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- International Collaborative Center on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
| | - Alexei Verkhratsky
- International Collaborative Center on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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14
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Rai MA, Hammonds J, Pujato M, Mayhew C, Roskin K, Spearman P. Comparative analysis of human microglial models for studies of HIV replication and pathogenesis. Retrovirology 2020; 17:35. [PMID: 33213476 PMCID: PMC7678224 DOI: 10.1186/s12977-020-00544-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
Background HIV associated neurocognitive disorders cause significant morbidity and mortality despite the advent of highly active antiretroviral therapy. A deeper understanding of fundamental mechanisms underlying HIV infection and pathogenesis in the central nervous system is warranted. Microglia are resident myeloid cells of the brain that are readily infected by HIV and may constitute a CNS reservoir. We evaluated two microglial model cell lines (C20, HMC3) and two sources of primary cell-derived microglia (monocyte-derived microglia [MMG] and induced pluripotent stem cell-derived microglia [iPSC-MG]) as potential model systems for studying HIV-microglia interactions. Results All four microglial model cells expressed typical myeloid markers with the exception of low or absent CD45 and CD11b expression by C20 and HMC3, and all four expressed the microglia-specific markers P2RY12 and TMEM119. Marked differences were observed upon gene expression profiling, however, indicating that MMG and iPSC-MG cluster closely together with primary human microglial cells, while C20 and HMC3 were similar to each other but very different from primary microglia. Expression of HIV-relevant genes also revealed important differences, with iPSC-MG and MMG expressing relevant genes at levels more closely resembling primary microglia. iPSC-MG and MMG were readily infected with R5-tropic HIV, while C20 and HMC3 lack CD4 and require pseudotyping for infection. Despite many similarities, HIV replication dynamics and HIV-1 particle capture by Siglec-1 differed markedly between the MMG and iPSC-MG. Conclusions MMG and iPSC-MG appear to be viable microglial models that are susceptible to HIV infection and bear more similarities to authentic microglia than two transformed microglia cell lines. The observed differences in HIV replication and particle capture between MMG and iPSC-MG warrant further study.
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Affiliation(s)
- Mohammad A Rai
- Division of Infectious Diseases, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7017, Cincinnati, OH, 45229, USA.,Division of Infectious Diseases, Department of Medicine, University of Cincinnati School of Medicine, Cincinnati, OH, USA
| | - Jason Hammonds
- Division of Infectious Diseases, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7017, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, OH, USA
| | - Mario Pujato
- Division of Biomedical Informatics, Cincinnati Children's Hospital, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, OH, USA
| | - Christopher Mayhew
- Pluripotent Stem Cell Core Facility, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Krishna Roskin
- Division of Biomedical Informatics, Cincinnati Children's Hospital, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, OH, USA
| | - Paul Spearman
- Division of Infectious Diseases, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7017, Cincinnati, OH, 45229, USA. .,Department of Pediatrics, University of Cincinnati School of Medicine, Cincinnati, OH, USA.
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