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Crapser JD, Arreola MA, Tsourmas KI, Green KN. Microglia as hackers of the matrix: sculpting synapses and the extracellular space. Cell Mol Immunol 2021; 18:2472-2488. [PMID: 34413489 PMCID: PMC8546068 DOI: 10.1038/s41423-021-00751-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia shape the synaptic environment in health and disease, but synapses do not exist in a vacuum. Instead, pre- and postsynaptic terminals are surrounded by extracellular matrix (ECM), which together with glia comprise the four elements of the contemporary tetrapartite synapse model. While research in this area is still just beginning, accumulating evidence points toward a novel role for microglia in regulating the ECM during normal brain homeostasis, and such processes may, in turn, become dysfunctional in disease. As it relates to synapses, microglia are reported to modify the perisynaptic matrix, which is the diffuse matrix that surrounds dendritic and axonal terminals, as well as perineuronal nets (PNNs), specialized reticular formations of compact ECM that enwrap neuronal subsets and stabilize proximal synapses. The interconnected relationship between synapses and the ECM in which they are embedded suggests that alterations in one structure necessarily affect the dynamics of the other, and microglia may need to sculpt the matrix to modify the synapses within. Here, we provide an overview of the microglial regulation of synapses, perisynaptic matrix, and PNNs, propose candidate mechanisms by which these structures may be modified, and present the implications of such modifications in normal brain homeostasis and in disease.
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Affiliation(s)
- Joshua D. Crapser
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Miguel A. Arreola
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kate I. Tsourmas
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kim N. Green
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
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52
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Basilico B, Ferrucci L, Ratano P, Golia MT, Grimaldi A, Rosito M, Ferretti V, Reverte I, Sanchini C, Marrone MC, Giubettini M, De Turris V, Salerno D, Garofalo S, St-Pierre MK, Carrier M, Renzi M, Pagani F, Modi B, Raspa M, Scavizzi F, Gross CT, Marinelli S, Tremblay MÈ, Caprioli D, Maggi L, Limatola C, Di Angelantonio S, Ragozzino D. Microglia control glutamatergic synapses in the adult mouse hippocampus. Glia 2021; 70:173-195. [PMID: 34661306 PMCID: PMC9297980 DOI: 10.1002/glia.24101] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/26/2022]
Abstract
Microglia cells are active players in regulating synaptic development and plasticity in the brain. However, how they influence the normal functioning of synapses is largely unknown. In this study, we characterized the effects of pharmacological microglia depletion, achieved by administration of PLX5622, on hippocampal CA3‐CA1 synapses of adult wild type mice. Following microglial depletion, we observed a reduction of spontaneous and evoked glutamatergic activity associated with a decrease of dendritic spine density. We also observed the appearance of immature synaptic features and higher levels of plasticity. Microglia depleted mice showed a deficit in the acquisition of the Novel Object Recognition task. These events were accompanied by hippocampal astrogliosis, although in the absence ofneuroinflammatory condition. PLX‐induced synaptic changes were absent in Cx3cr1−/− mice, highlighting the role of CX3CL1/CX3CR1 axis in microglia control of synaptic functioning. Remarkably, microglia repopulation after PLX5622 withdrawal was associated with the recovery of hippocampal synapses and learning functions. Altogether, these data demonstrate that microglia contribute to normal synaptic functioning in the adult brain and that their removal induces reversible changes in organization and activity of glutamatergic synapses.
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Affiliation(s)
- Bernadette Basilico
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Laura Ferrucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Patrizia Ratano
- Neurophysiology and Neuropharmacology Inflammaging Unit, IRCCS Neuromed, Mediterranean Neurological Institute, Pozzilli, IS, Italy
| | - Maria T Golia
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Alfonso Grimaldi
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Maria Rosito
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Valentina Ferretti
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Ingrid Reverte
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - Caterina Sanchini
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Maria C Marrone
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Maria Giubettini
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy.,CrestOptics S.p.A, Rome, Italy
| | - Valeria De Turris
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Debora Salerno
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Marie-Kim St-Pierre
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada
| | - Micael Carrier
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada
| | - Massimiliano Renzi
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Francesca Pagani
- Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Brijesh Modi
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Marcello Raspa
- National Research Council, Institute of Biochemistry and Cell Biology (CNR-IBBC/EMMA/Infrafrontier/IMPC), International Campus "A. Buzzati-Traverso", Monterotondo (Rome), Italy
| | - Ferdinando Scavizzi
- National Research Council, Institute of Biochemistry and Cell Biology (CNR-IBBC/EMMA/Infrafrontier/IMPC), International Campus "A. Buzzati-Traverso", Monterotondo (Rome), Italy
| | - Cornelius T Gross
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory (EMBL), Monterotondo, Italy
| | - Silvia Marinelli
- European Brain Research Institute (EBRI) 'Rita Levi-Montalcini', Rome, Italy
| | - Marie-Ève Tremblay
- Centre de Recherche du CHU de Québec, Axe Neurosciences Québec, Quebec City, Canada.,Département de Médecine Moléculaire, Université Laval Québec, Quebec City, Canada.,Division of Medical Sciences, University of Victoria, Victoria, Canada
| | - Daniele Caprioli
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - Laura Maggi
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Cristina Limatola
- Neurophysiology and Neuropharmacology Inflammaging Unit, IRCCS Neuromed, Mediterranean Neurological Institute, Pozzilli, IS, Italy.,Department of Physiology and Pharmacology, Sapienza University, Laboratory affiliated to Istituto Pasteur Italia, Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Center for Life Nano- and Neuro-science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
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Forner S, Kawauchi S, Balderrama-Gutierrez G, Kramár EA, Matheos DP, Phan J, Javonillo DI, Tran KM, Hingco E, da Cunha C, Rezaie N, Alcantara JA, Baglietto-Vargas D, Jansen C, Neumann J, Wood MA, MacGregor GR, Mortazavi A, Tenner AJ, LaFerla FM, Green KN. Systematic phenotyping and characterization of the 5xFAD mouse model of Alzheimer's disease. Sci Data 2021; 8:270. [PMID: 34654824 PMCID: PMC8519958 DOI: 10.1038/s41597-021-01054-y] [Citation(s) in RCA: 139] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/02/2021] [Indexed: 12/13/2022] Open
Abstract
Mouse models of human diseases are invaluable tools for studying pathogenic mechanisms and testing interventions and therapeutics. For disorders such as Alzheimer's disease in which numerous models are being generated, a challenging first step is to identify the most appropriate model and age to effectively evaluate new therapeutic approaches. Here we conducted a detailed phenotypic characterization of the 5xFAD model on a congenic C57BL/6 J strain background, across its lifespan - including a seldomly analyzed 18-month old time point to provide temporally correlated phenotyping of this model and a template for characterization of new models of LOAD as they are generated. This comprehensive analysis included quantification of plaque burden, Aβ biochemical levels, and neuropathology, neurophysiological measurements and behavioral and cognitive assessments, and evaluation of microglia, astrocytes, and neurons. Analysis of transcriptional changes was conducted using bulk-tissue generated RNA-seq data from microdissected cortices and hippocampi as a function of aging, which can be explored at the MODEL-AD Explorer and AD Knowledge Portal. This deep-phenotyping pipeline identified novel aspects of age-related pathology in the 5xFAD model.
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Affiliation(s)
- Stefania Forner
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Shimako Kawauchi
- Transgenic Mouse Facility, University Laboratory Animal Resources, Office of Research, University of California, Irvine, CA, 92697, USA
| | - Gabriela Balderrama-Gutierrez
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA
| | - Enikö A Kramár
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA
| | - Dina P Matheos
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA
| | - Jimmy Phan
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Dominic I Javonillo
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Kristine M Tran
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Edna Hingco
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Celia da Cunha
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Narges Rezaie
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA
| | - Joshua A Alcantara
- Transgenic Mouse Facility, University Laboratory Animal Resources, Office of Research, University of California, Irvine, CA, 92697, USA
| | - David Baglietto-Vargas
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
| | - Camden Jansen
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA
| | - Jonathan Neumann
- Transgenic Mouse Facility, University Laboratory Animal Resources, Office of Research, University of California, Irvine, CA, 92697, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA
| | - Grant R MacGregor
- Transgenic Mouse Facility, University Laboratory Animal Resources, Office of Research, University of California, Irvine, CA, 92697, USA
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
- Center for Complex Biological Systems, University of California, Irvine, CA, 92697, USA
| | - Andrea J Tenner
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, 92697, USA
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA, 92697, USA
| | - Frank M LaFerla
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA
| | - Kim N Green
- Institute for Memory Impairments and Neurological Disorders (UCI MIND), University of California, Irvine, CA, 92697, USA.
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697, USA.
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54
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Qiu S, Palavicini JP, Wang J, Gonzalez NS, He S, Dustin E, Zou C, Ding L, Bhattacharjee A, Van Skike CE, Galvan V, Dupree JL, Han X. Adult-onset CNS myelin sulfatide deficiency is sufficient to cause Alzheimer's disease-like neuroinflammation and cognitive impairment. Mol Neurodegener 2021; 16:64. [PMID: 34526055 PMCID: PMC8442347 DOI: 10.1186/s13024-021-00488-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Human genetic association studies point to immune response and lipid metabolism, in addition to amyloid-beta (Aβ) and tau, as major pathways in Alzheimer's disease (AD) etiology. Accumulating evidence suggests that chronic neuroinflammation, mainly mediated by microglia and astrocytes, plays a causative role in neurodegeneration in AD. Our group and others have reported early and dramatic losses of brain sulfatide in AD cases and animal models that are mediated by ApoE in an isoform-dependent manner and accelerated by Aβ accumulation. To date, it remains unclear if changes in specific brain lipids are sufficient to drive AD-related pathology. METHODS To study the consequences of CNS sulfatide deficiency and gain insights into the underlying mechanisms, we developed a novel mouse model of adult-onset myelin sulfatide deficiency, i.e., tamoxifen-inducible myelinating glia-specific cerebroside sulfotransferase (CST) conditional knockout mice (CSTfl/fl/Plp1-CreERT), took advantage of constitutive CST knockout mice (CST-/-), and generated CST/ApoE double knockout mice (CST-/-/ApoE-/-), and assessed these mice using a broad range of methodologies including lipidomics, RNA profiling, behavioral testing, PLX3397-mediated microglia depletion, mass spectrometry (MS) imaging, immunofluorescence, electron microscopy, and Western blot. RESULTS We found that mild central nervous system (CNS) sulfatide losses within myelinating cells are sufficient to activate disease-associated microglia and astrocytes, and to increase the expression of AD risk genes (e.g., Apoe, Trem2, Cd33, and Mmp12), as well as previously established causal regulators of the immune/microglia network in late-onset AD (e.g., Tyrobp, Dock, and Fcerg1), leading to chronic AD-like neuroinflammation and mild cognitive impairment. Notably, neuroinflammation and mild cognitive impairment showed gender differences, being more pronounced in females than males. Subsequent mechanistic studies demonstrated that although CNS sulfatide losses led to ApoE upregulation, genetically-induced myelin sulfatide deficiency led to neuroinflammation independently of ApoE. These results, together with our previous studies (sulfatide deficiency in the context of AD is mediated by ApoE and accelerated by Aβ accumulation) placed both Aβ and ApoE upstream of sulfatide deficiency-induced neuroinflammation, and suggested a positive feedback loop where sulfatide losses may be amplified by increased ApoE expression. We also demonstrated that CNS sulfatide deficiency-induced astrogliosis and ApoE upregulation are not secondary to microgliosis, and that astrogliosis and microgliosis seem to be driven by activation of STAT3 and PU.1/Spi1 transcription factors, respectively. CONCLUSION Our results strongly suggest that sulfatide deficiency is an important contributor and driver of neuroinflammation and mild cognitive impairment in AD pathology.
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Affiliation(s)
- Shulan Qiu
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
| | - Juan Pablo Palavicini
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Jianing Wang
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
- Present Address: State Key Lab. of Environmental & Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hongkong, China
| | - Nancy S Gonzalez
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
| | - Sijia He
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
| | - Elizabeth Dustin
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, 23284, USA
| | - Cheng Zou
- BRC Bioinformatics Facility, Institute of Biotechnology, Cornell University, Ithaca, NY, 14853, USA
| | - Lin Ding
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Anindita Bhattacharjee
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
| | - Candice E Van Skike
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Veronica Galvan
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, 23284, USA
- Research Division, McGuire Veterans Affairs Medical Center, Richmond, Virginia, 23249, USA
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 4939 Charles Katz Drive, San Antonio, TX, 78229, USA.
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
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55
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Affiliation(s)
- Lorna Bo
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Xuenong Bo
- Centre for Neuroscience, Surgery and Trauma, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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56
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Fague L, Liu YA, Marsh-Armstrong N. The basic science of optic nerve regeneration. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1276. [PMID: 34532413 PMCID: PMC8421956 DOI: 10.21037/atm-20-5351] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/15/2021] [Indexed: 12/25/2022]
Abstract
Diverse insults to the optic nerve result in partial to total vision loss as the axons of retinal ganglion cells are destroyed. In glaucoma, axons are injured at the optic nerve head; in other optic neuropathies, axons can be damaged along the entire visual pathway. In all cases, as mammals cannot regenerate injured central nervous system cells, once the axons are lost, vision loss is irreversible. However, much has been learned about how retinal ganglion cells respond to axon injuries, and many of these crucial discoveries offer hope for future regenerative therapies. Here we review the current understanding regarding the temporal progression of axonal degeneration. We summarize known survival and regenerative mechanisms in mammals, including specific signaling pathways, key transcription factors, and reprogramming genes. We cover mechanisms intrinsic to retinal ganglion cells as well as their interactions with myeloid and glial cell populations in the retina and optic nerve that affect survival and regeneration. Finally, we highlight some non-mammalian species that are able to regenerate their retinal ganglion cell axons after injury, as understanding these successful regenerative responses may be essential to the rational design of future clinical interventions to regrow the optic nerve. In the end, a combination of many different molecular and cellular interventions will likely be the only way to achieve functional recovery of vision and restore quality of life to millions of patients around the world.
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Affiliation(s)
- Lindsay Fague
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
| | - Yin Allison Liu
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
| | - Nicholas Marsh-Armstrong
- UC Davis Eye Center, Department of Ophthalmology & Vision Science, University of California, Davis, Sacramento, CA, USA
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57
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Li Q, Shen C, Liu Z, Ma Y, Wang J, Dong H, Zhang X, Wang Z, Yu M, Ci L, Sun R, Shen R, Fei J, Huang F. Partial depletion and repopulation of microglia have different effects in the acute MPTP mouse model of Parkinson's disease. Cell Prolif 2021; 54:e13094. [PMID: 34312932 PMCID: PMC8349650 DOI: 10.1111/cpr.13094] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVES Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the progressive and selective degeneration of dopaminergic neurons. Microglial activation and neuroinflammation are associated with the pathogenesis of PD. However, the relationship between microglial activation and PD pathology remains to be explored. MATERIALS AND METHODS An acute regimen of MPTP was administered to adult C57BL/6J mice with normal, much reduced or repopulated microglial population. Damages of the dopaminergic system were comprehensively assessed. Inflammation-related factors were assessed by quantitative PCR and Multiplex immunoassay. Behavioural tests were carried out to evaluate the motor deficits in MPTP-challenged mice. RESULTS The receptor for colony-stimulating factor 1 inhibitor PLX3397 could effectively deplete microglia in the nigrostriatal pathway of mice via feeding a PLX3397-formulated diet for 21 days. Microglial depletion downregulated both pro-inflammatory and anti-inflammatory molecule expression at baseline and after MPTP administration. At 1d post-MPTP injection, dopaminergic neurons showed a significant reduction in PLX3397-fed mice, but not in control diet (CD)-fed mice. However, partial microglial depletion in mice exerted little effect on MPTP-induced dopaminergic injuries compared with CD mice at later time points. Interestingly, microglial repopulation brought about apparent resistance to MPTP intoxication. CONCLUSIONS Microglia can inhibit PD development at a very early stage; partial microglial depletion has little effect in terms of the whole process of the disease; and microglial replenishment elicits neuroprotection in PD mice.
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Affiliation(s)
- Qing Li
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China.,Shanghai Engineering Research Center for Model Organisms, Shanghai Model Organisms Center, INC, Shanghai, China
| | - Chenye Shen
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Zhaolin Liu
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yuanyuan Ma
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Jinghui Wang
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Hongtian Dong
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xiaoshuang Zhang
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Zishan Wang
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Mei Yu
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
| | - Lei Ci
- Shanghai Engineering Research Center for Model Organisms, Shanghai Model Organisms Center, INC, Shanghai, China
| | - Ruilin Sun
- Shanghai Engineering Research Center for Model Organisms, Shanghai Model Organisms Center, INC, Shanghai, China
| | - Ruling Shen
- Joint Laboratory for Technology of Model Organism, Shanghai Laboratory Animal Research Center and School of Life Science and Technology, Tongji University.,Shanghai Laboratory Animal Research Center, Shanghai, China
| | - Jian Fei
- Joint Laboratory for Technology of Model Organism, Shanghai Laboratory Animal Research Center and School of Life Science and Technology, Tongji University.,Shanghai Laboratory Animal Research Center, Shanghai, China.,School of Life Science and Technology, Tongji University, Shanghai, China
| | - Fang Huang
- Department of Translational Neuroscience, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Jing' an District Centre Hospital of Shanghai Institutes of Brain Science, Fudan University, Shanghai, China
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58
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Strackeljan L, Baczynska E, Cangalaya C, Baidoe-Ansah D, Wlodarczyk J, Kaushik R, Dityatev A. Microglia Depletion-Induced Remodeling of Extracellular Matrix and Excitatory Synapses in the Hippocampus of Adult Mice. Cells 2021; 10:1862. [PMID: 34440631 PMCID: PMC8393852 DOI: 10.3390/cells10081862] [Citation(s) in RCA: 33] [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: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 12/13/2022] Open
Abstract
The extracellular matrix (ECM) plays a key role in synaptogenesis and the regulation of synaptic functions in the central nervous system. Recent studies revealed that in addition to dopaminergic and serotoninergic neuromodulatory systems, microglia also contribute to the regulation of ECM remodeling. In the present work, we investigated the physiological role of microglia in the remodeling of perineuronal nets (PNNs), predominantly associated with parvalbumin-immunopositive (PV+) interneurons, and the perisynaptic ECM around pyramidal neurons in the hippocampus. Adult mice were treated with PLX3397 (pexidartinib), as the inhibitor of colony-stimulating factor 1 receptor (CSF1-R), to deplete microglia. Then, confocal analysis of the ECM and synapses was performed. Although the elimination of microglia did not alter the overall number or intensity of PNNs in the CA1 region of the hippocampus, it decreased the size of PNN holes and elevated the expression of the surrounding ECM. In the neuropil area in the CA1 str. radiatum, the depletion of microglia increased the expression of perisynaptic ECM proteoglycan brevican, which was accompanied by the elevated expression of presynaptic marker vGluT1 and the increased density of dendritic spines. Thus, microglia regulate the homeostasis of pre- and postsynaptic excitatory terminals and the surrounding perisynaptic ECM as well as the fine structure of PNNs enveloping perisomatic-predominantly GABAergic-synapses.
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Affiliation(s)
- Luisa Strackeljan
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; (L.S.); (C.C.); (D.B.-A.)
| | - Ewa Baczynska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; (E.B.); (J.W.)
| | - Carla Cangalaya
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; (L.S.); (C.C.); (D.B.-A.)
- Institut für Biochemie und Zellbiologie, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany
- ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory Processes, 39120 Magdeburg, Germany
| | - David Baidoe-Ansah
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; (L.S.); (C.C.); (D.B.-A.)
| | - Jakub Wlodarczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; (E.B.); (J.W.)
| | - Rahul Kaushik
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; (L.S.); (C.C.); (D.B.-A.)
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany; (L.S.); (C.C.); (D.B.-A.)
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
- Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany
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59
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Mendes MS, Le L, Atlas J, Brehm Z, Ladron-de-Guevara A, Matei E, Lamantia C, McCall MN, Majewska AK. The role of P2Y12 in the kinetics of microglial self-renewal and maturation in the adult visual cortex in vivo. eLife 2021; 10:61173. [PMID: 34250902 PMCID: PMC8341987 DOI: 10.7554/elife.61173] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 07/10/2021] [Indexed: 12/31/2022] Open
Abstract
Microglia are the brain’s resident immune cells with a tremendous capacity to autonomously self-renew. Because microglial self-renewal has largely been studied using static tools, its mechanisms and kinetics are not well understood. Using chronic in vivo two-photon imaging in awake mice, we confirm that cortical microglia show limited turnover and migration under basal conditions. Following depletion, however, microglial repopulation is remarkably rapid and is sustained by the dynamic division of remaining microglia, in a manner that is largely independent of signaling through the P2Y12 receptor. Mathematical modeling of microglial division demonstrates that the observed division rates can account for the rapid repopulation observed in vivo. Additionally, newly born microglia resemble mature microglia within days of repopulation, although morphological maturation is different in newly born microglia in P2Y12 knock out mice. Our work suggests that microglia rapidly locally and that newly born microglia do not recapitulate the slow maturation seen in development but instead take on mature roles in the CNS.
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Affiliation(s)
- Monique S Mendes
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States
| | - Linh Le
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States
| | - Jason Atlas
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States
| | - Zachary Brehm
- Department of Biostatistics, University of Rochester Medical Center, Rochester, United States
| | - Antonio Ladron-de-Guevara
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States.,Department of Biomedical Engineering, University of Rochester, Rochester, United States
| | - Evelyn Matei
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States
| | - Cassandra Lamantia
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States
| | - Matthew N McCall
- Department of Biostatistics, University of Rochester Medical Center, Rochester, United States
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, United States.,Center for Visual Science, University of Rochester, Rochester, United States
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60
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Vitamin K2 Holds Promise for Alzheimer's Prevention and Treatment. Nutrients 2021; 13:nu13072206. [PMID: 34199021 PMCID: PMC8308377 DOI: 10.3390/nu13072206] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/24/2021] [Accepted: 06/24/2021] [Indexed: 12/24/2022] Open
Abstract
Recent studies have highlighted the importance of vitamin K2 (VK2) in human health. However, there have been no clinical studies investigating the role of VK2 in the prevention or treatment of Alzheimer's disease (AD), a debilitating disease for which currently there is no cure. In reviewing basic science research and clinical studies that have connected VK2 to factors involved in AD pathogenesis, we have found a growing body of evidence demonstrating that VK2 has the potential to slow the progression of AD and contribute to its prevention. In our review, we consider the antiapoptotic and antioxidant effects of VK2 and its impact on neuroinflammation, mitochondrial dysfunction, cognition, cardiovascular health, and comorbidities in AD. We also examine the link between dysbiosis and VK2 in the context of the microbiome's role in AD pathogenesis. Our review is the first to consider the physiological roles of VK2 in the context of AD, and, given the recent shift in AD research toward nonpharmacological interventions, our findings emphasize the timeliness and need for clinical studies involving VK2.
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61
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Wyatt-Johnson SK, Sommer AL, Shim KY, Brewster AL. Suppression of Microgliosis With the Colony-Stimulating Factor 1 Receptor Inhibitor PLX3397 Does Not Attenuate Memory Defects During Epileptogenesis in the Rat. Front Neurol 2021; 12:651096. [PMID: 34149593 PMCID: PMC8209304 DOI: 10.3389/fneur.2021.651096] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 05/11/2021] [Indexed: 12/03/2022] Open
Abstract
Events of status epilepticus (SE) trigger the development of temporal lobe epilepsy (TLE), a type of focal epilepsy that is commonly drug-resistant and is highly comorbid with cognitive deficits. While SE-induced hippocampal injury, accompanied by gliosis and neuronal loss, typically disrupts cognitive functions resulting in memory defects, it is not definitively known how. Our previous studies revealed extensive hippocampal microgliosis that peaked between 2 and 3 weeks after SE and paralleled the development of cognitive impairments, suggesting a role for reactive microglia in this pathophysiology. Microglial survival and proliferation are regulated by the colony-stimulating factor 1 receptor (CSF1R). The CSF1R inhibitor PLX3397 has been shown to reduce/deplete microglial populations and improve cognitive performance in models of neurodegenerative disorders. Therefore, we hypothesized that suppression of microgliosis with PLX3397 during epileptogenesis may attenuate the hippocampal-dependent spatial learning and memory deficits in the rat pilocarpine model of SE and acquired TLE. Different groups of control and SE rats were fed standard chow (SC) or chow with PLX3397 starting immediately after SE and for 3 weeks. Novel object recognition (NOR) and Barnes maze (BM) were performed to determine memory function between 2 and 3 weeks after SE. Then microglial populations were assessed using immunohistochemistry. Control rats fed with either SC or PLX3397 performed similarly in both NOR and BM tests, differentiating novel vs. familiar objects in NOR, and rapidly learning the location of the hidden platform in BM. In contrast, both SE groups (SC and PLX3397) showed significant deficits in both NOR and BM tests compared to controls. Both PLX3397-treated control and SE groups had significantly decreased numbers of microglia in the hippocampus (60%) compared to those in SC. In parallel, we found that PLX3397 treatment also reduced SE-induced hippocampal astrogliosis. Thus, despite drastic reductions in microglial cells, memory was unaffected in the PLX3397-treated groups compared to those in SC, suggesting that remaining microglia may be sufficient to help maintain hippocampal functions. In sum, PLX3397 did not improve or worsen the memory deficits in rats that sustained pilocarpine-induced SE. Further research is required to determine whether microglia play a role in cognitive decline during epileptogenesis.
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Affiliation(s)
- Season K Wyatt-Johnson
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Alexandra L Sommer
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Kevin Y Shim
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States
| | - Amy L Brewster
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, United States.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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62
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Mendes MS, Majewska AK. An overview of microglia ontogeny and maturation in the homeostatic and pathological brain. Eur J Neurosci 2021; 53:3525-3547. [PMID: 33835613 PMCID: PMC8225243 DOI: 10.1111/ejn.15225] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/17/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022]
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and are increasingly recognized as critical players in development, brain homeostasis, and disease pathogenesis. The lifespan, maintenance, proliferation, and turnover of microglia are important factors that regulate microglial behavior and affect their roles in the CNS. However, emerging evidence suggests that microglia are morphologically and phenotypically distinct in different brain areas, at different ages, and during disease. Ongoing research focuses on understanding how microglia acquire specific phenotypes in response to extrinsic cues in the environment and how phenotypes are specified by intrinsic properties of different populations of microglia. With the development of pharmacological and genetic tools that allow the investigation of microglia in vivo, there have been considerable advances in understanding molecular signatures of both homeostatic microglia and those reacting to injury and disease. Here, we review the master gene regulators that define microglia as well as discuss the evidence that microglia are heterogeneous and fall into distinct clusters that display specific intrinsic properties and perform unique tasks in different settings. Taken together, the information presented supports the idea that microglia morphology and transcriptional heterogeneity should be considered when studying the complex nature of microglia and their roles in brain health and disease.
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Affiliation(s)
- Monique S Mendes
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
- Center for Visual Science, University of Rochester, Rochester, NY, USA
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63
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Kono R, Ikegaya Y, Koyama R. Phagocytic Glial Cells in Brain Homeostasis. Cells 2021; 10:1348. [PMID: 34072424 PMCID: PMC8229427 DOI: 10.3390/cells10061348] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Phagocytosis by glial cells has been shown to play an important role in maintaining brain homeostasis. Microglia are currently considered to be the major phagocytes in the brain parenchyma, and these cells phagocytose a variety of materials, including dead cell debris, abnormally aggregated proteins, and, interestingly, the functional synapses of living neurons. The intracellular signaling mechanisms that regulate microglial phagocytosis have been studied extensively, and several important factors, including molecules known as "find me" signals and "eat me" signals and receptors on microglia that are involved in phagocytosis, have been identified. In addition, recent studies have revealed that astrocytes, which are another major glial cell in the brain parenchyma, also have phagocytic abilities. In this review, we will discuss the roles of microglia and astrocytes in phagocytosis-mediated brain homeostasis, focusing on the characteristics and differences of their phagocytic abilities.
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Affiliation(s)
- Rena Kono
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
- Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City 565-0871, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.K.); (Y.I.)
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64
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Saxena S, Kruys V, Vamecq J, Maze M. The Role of Microglia in Perioperative Neuroinflammation and Neurocognitive Disorders. Front Aging Neurosci 2021; 13:671499. [PMID: 34122048 PMCID: PMC8193130 DOI: 10.3389/fnagi.2021.671499] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/04/2021] [Indexed: 12/14/2022] Open
Abstract
The aseptic trauma of peripheral surgery activates a systemic inflammatory response that results in neuro-inflammation; the microglia, the resident immunocompetent cells in the brain, are a key element of the neuroinflammatory response. In most settings microglia perform a surveillance role in the brain detecting and responding to “invaders” to maintain homeostasis. However, microglia have also been implicated in producing harm possibly by changing its phenotype from its beneficial, anti-inflammatory state (termed M2) into an injurious pro-inflammatory state (termed M1); it is likely that there are intermediates states between these polar phenotypes and some consider that a gradient exists with a number of intermediates, rather than a strict dichotomy between M1 and M2. In the pro-inflammatory phenotypes, microglia can disrupt synaptic plasticity such as long- term potentiation that can result in disorders of learning and memory of the type observed in Peri-operative Neurocognitive Disorders. Therefore, investigators have sought strategies to prevent microglia from provoking this adverse event in the perioperative period. In preclinical studies microglia can be depleted by removing trophic factors required for its maintenance; subsequent repopulation with a more beneficial microglial phenotype may result in memory enhancement, improved sensory motor function, as well as suppression of neuroinflammatory and oxidative stress pathways. Another approach consists of preventing microglial activation using the non-specific P38 MAP kinase blockers such as minocycline. Perhaps a more physiologic approach is the use of inhibitors of potassium (K+) channels that are required to convert the microglia into an active state. In this context the specific K+ channels that are implicated are termed Kv1.3 and KCa3.1 and high selective inhibitors for each have been developed. Data are accumulating demonstrating the utility of these K+ channel blockers in preventing Perioperative Neurocognitive Disorders.
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Affiliation(s)
- Sarah Saxena
- Department of Anesthesia, University Hospital Center (CHU de Charleroi), Charleroi, Belgium.,Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, San Francisco, CA, United States
| | - Veronique Kruys
- Laboratory of Molecular Biology of the Gene, Department of Molecular Biology, ULB Immunology Research Center (UIRC), Free University of Brussels (ULB), Gosselies, Belgium
| | - Joseph Vamecq
- Inserm, CHU Lille, Univ Lille, Department of Biochemistry and Molecular Biology, Laboratory of Hormonology, Metabolism-Nutrition and Oncology (HMNO), Center of Biology and Pathology (CBP) Pierre-Marie Degand, CHRU Lille, University of North France, Lille, France
| | - Mervyn Maze
- Department of Anesthesia and Perioperative Care, Center for Cerebrovascular Research, University of California, San Francisco, San Francisco, CA, United States
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65
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Semaphorin3A increases M1-like microglia and retinal ganglion cell apoptosis after optic nerve injury. Cell Biosci 2021; 11:97. [PMID: 34039431 PMCID: PMC8157735 DOI: 10.1186/s13578-021-00603-7] [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: 02/18/2021] [Accepted: 05/04/2021] [Indexed: 11/10/2022] Open
Abstract
Background The mechanisms leading to retinal ganglion cell (RGC) death after optic nerve injury have not been fully elucidated. Current evidence indicates that microglial activation and M1- and M2-like dynamics may be an important factor in RGC apoptosis after optic nerve crush (ONC). Semaphorin3A (Sema3A) is a classic axonal guidance protein,which has been found to have a role in neuroinflammation processes. In this study, we investigated the contribution of microglial-derived Sema3A to progressive RGC apoptosis through regulating paradigm of M1- and M2-like microglia after ONC. Method
A mouse ONC model and a primary microglial-RGC co-culture system were used in the present study. The expression of M1- and M2-like microglial activation markers were assessed by real-time polymerase chain reaction (RT-qPCR). Histological and Western blot (WB) analyses were used to investigate the polarization patterns of microglia transitions and the levels of Sema3A. RGC apoptosis was investigated by TUNEL staining and caspase-3 detection. Results Levels of Sema3A in the mouse retina increased after ONC. Treatment of mice with the stimulating factor 1 receptor antagonist PLX3397 resulted in a decrease of retinal microglia. The levels of CD16/32 (M1) were up-regulated at days 3 and 7 post-ONC. However, CD206 (M2) declined on day 7 after ONC. Exposure to anti-Sema3A antibodies (anti-Sema3A) resulted in a decrease in the number of M1-like microglia, an increase in the number of M2-like microglia, and the amelioration of RGC apoptosis. Conclusions An increase in microglia-derived Sema3A in the retina after ONC partially leads to a continuous increase of M1-like microglia and plays an important role in RGC apoptosis. Inhibition of Sema3A activity may be a novel approach to the prevention of RGC apoptosis after optic nerve injury. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-021-00603-7.
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66
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Andrew PM, Lein PJ. Neuroinflammation as a Therapeutic Target for Mitigating the Long-Term Consequences of Acute Organophosphate Intoxication. Front Pharmacol 2021; 12:674325. [PMID: 34054549 PMCID: PMC8153682 DOI: 10.3389/fphar.2021.674325] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/30/2021] [Indexed: 12/14/2022] Open
Abstract
Acute intoxication with organophosphates (OPs) can cause a potentially fatal cholinergic crisis characterized by peripheral parasympathomimetic symptoms and seizures that rapidly progress to status epilepticus (SE). While current therapeutic countermeasures for acute OP intoxication significantly improve the chances of survival when administered promptly, they are insufficient for protecting individuals from chronic neurologic outcomes such as cognitive deficits, affective disorders, and acquired epilepsy. Neuroinflammation is posited to contribute to the pathogenesis of these long-term neurologic sequelae. In this review, we summarize what is currently known regarding the progression of neuroinflammatory responses after acute OP intoxication, drawing parallels to other models of SE. We also discuss studies in which neuroinflammation was targeted following OP-induced SE, and explain possible reasons why such therapeutic interventions have inconsistently and only partially improved long-term outcomes. Finally, we suggest future directions for the development of therapeutic strategies that target neuroinflammation to mitigate the neurologic sequelae of acute OP intoxication.
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Affiliation(s)
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, United States
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67
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Socodato R, Portugal CC, Canedo T, Rodrigues A, Almeida TO, Henriques JF, Vaz SH, Magalhães J, Silva CM, Baptista FI, Alves RL, Coelho-Santos V, Silva AP, Paes-de-Carvalho R, Magalhães A, Brakebusch C, Sebastião AM, Summavielle T, Ambrósio AF, Relvas JB. Microglia Dysfunction Caused by the Loss of Rhoa Disrupts Neuronal Physiology and Leads to Neurodegeneration. Cell Rep 2021; 31:107796. [PMID: 32579923 DOI: 10.1016/j.celrep.2020.107796] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 05/29/2019] [Accepted: 06/01/2020] [Indexed: 12/28/2022] Open
Abstract
Nervous tissue homeostasis requires the regulation of microglia activity. Using conditional gene targeting in mice, we demonstrate that genetic ablation of the small GTPase Rhoa in adult microglia is sufficient to trigger spontaneous microglia activation, producing a neurological phenotype (including synapse and neuron loss, impairment of long-term potentiation [LTP], formation of β-amyloid plaques, and memory deficits). Mechanistically, loss of Rhoa in microglia triggers Src activation and Src-mediated tumor necrosis factor (TNF) production, leading to excitotoxic glutamate secretion. Inhibiting Src in microglia Rhoa-deficient mice attenuates microglia dysregulation and the ensuing neurological phenotype. We also find that the Rhoa/Src signaling pathway is disrupted in microglia of the APP/PS1 mouse model of Alzheimer disease and that low doses of Aβ oligomers trigger microglia neurotoxic polarization through the disruption of Rhoa-to-Src signaling. Overall, our results indicate that disturbing Rho GTPase signaling in microglia can directly cause neurodegeneration.
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Affiliation(s)
- Renato Socodato
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Camila C Portugal
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Teresa Canedo
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Artur Rodrigues
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Tiago O Almeida
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Joana F Henriques
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Sandra H Vaz
- Instituto de Farmacologia e Neurociências, Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - João Magalhães
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Cátia M Silva
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Filipa I Baptista
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal
| | - Renata L Alves
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Vanessa Coelho-Santos
- Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Ana Paula Silva
- Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Roberto Paes-de-Carvalho
- Department of Neurobiology and Program of Neurosciences, Institute of Biology, Fluminense Federal University, Niterói, Brazil
| | - Ana Magalhães
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Cord Brakebusch
- Molecular Pathology Section, BRIC, Københavns Biocenter, Copenhagen, Denmark
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Teresa Summavielle
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal; Escola Superior de Saúde, Politécnico do Porto, Porto, Portugal
| | - António F Ambrósio
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), Faculty of Medicine, Coimbra, Portugal; Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | - João B Relvas
- Instituto de Investigação e Inovação em Saúde and Instituto de Biologia Molecular e Celular, Porto, Portugal; Faculdade de Medicina, Universidade do Porto, Porto, Portugal; The Discoveries Centre for Regeneration and Precision Medicine, Porto Campus, Porto, Portugal.
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68
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Sharon A, Jankowski MM, Shmoel N, Erez H, Spira ME. Inflammatory Foreign Body Response Induced by Neuro-Implants in Rat Cortices Depleted of Resident Microglia by a CSF1R Inhibitor and Its Implications. Front Neurosci 2021; 15:646914. [PMID: 33841088 PMCID: PMC8032961 DOI: 10.3389/fnins.2021.646914] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/25/2021] [Indexed: 12/30/2022] Open
Abstract
Inflammatory encapsulation of implanted cortical-neuro-probes [the foreign body response (FBR)] severely limits their use in basic brain research and in clinical applications. A better understanding of the inflammatory FBR is needed to effectively mitigate these critical limitations. Combining the use of the brain permeant colony stimulating factor 1 receptor inhibitor PLX5622 and a perforated polyimide-based multielectrode array platform (PPMP) that can be sectioned along with the surrounding tissue, we examined the contribution of microglia to the formation of inflammatory FBR. To that end, we imaged the inflammatory processes induced by PPMP implantations after eliminating 89-94% of the cortical microglia by PLX5622 treatment. The observations showed that: (I) inflammatory encapsulation of implanted PPMPs proceeds by astrocytes in microglia-free cortices. The activated astrocytes adhered to the PPMP's surfaces. This suggests that the roles of microglia in the FBR might be redundant. (II) PPMP implantation into control or continuously PLX5622-treated rats triggered a localized surge of microglia mitosis. The daughter cells that formed a "cloud" of short-lived (T 1 / 2 ≤ 14 days) microglia around and in contact with the implant surfaces were PLX5622 insensitive. (III) Neuron degeneration by PPMP implantation and the ensuing recovery in time, space, and density progressed in a similar manner in the cortices following 89-94% depletion of microglia. This implies that microglia do not serve a protective role with respect to the neurons. (IV) Although the overall cell composition and dimensions of the encapsulating scar in PLX5622-treated rats differed from the controls, the recorded field potential (FP) qualities and yield were undistinguishable. This is accounted for by assuming that the FP amplitudes in the control and PLX5622-treated rats were related to the seal resistance formed at the interface between the adhering microglia and/or astrocytes and the PPMP platform rather than across the scar tissue. These observations suggest that the prevention of both astrocytes and microglia adhesion to the electrodes is required to improve FP recording quality and yield.
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Affiliation(s)
- Aviv Sharon
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maciej M. Jankowski
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nava Shmoel
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Micha E. Spira
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Charles E. Smith Family and Prof. Joel Elkes Laboratory for Collaborative Research in Psychobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- The Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem, Jerusalem, Israel
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69
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Li T, Zhao J, Xie W, Yuan W, Guo J, Pang S, Gan WB, Gómez-Nicola D, Zhang S. Specific depletion of resident microglia in the early stage of stroke reduces cerebral ischemic damage. J Neuroinflammation 2021; 18:81. [PMID: 33757565 PMCID: PMC7986495 DOI: 10.1186/s12974-021-02127-w] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/11/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ischemia can induce rapid activation of microglia in the brain. As key immunocompetent cells, reactive microglia play an important role in pathological development of ischemic stroke. However, the role of activated microglia during the development of ischemia remains controversial. Thus, we aimed to investigate the function of reactive microglia in the early stage of ischemic stroke. METHODS A Rose Bengal photothrombosis model was applied to induce targeted ischemic stroke in mice. CX3CR1CreER:R26iDTR mice were used to specifically deplete resident microglia through intragastric administration of tamoxifen (Ta) and intraperitoneal injection of diphtheria toxin (DT). At day 3 after ischemic stroke, behavioral tests were performed. After that, mouse brains were collected for further histological analysis and detection of mRNA expression of inflammatory factors. RESULTS The results showed that specific depletion of microglia resulted in a significant decrease in ischemic infarct volume and improved performance in motor ability 3 days after stroke. Microglial depletion caused a remarkable reduction in the densities of degenerating neurons and inducible nitric oxide synthase positive (iNOS+) cells. Importantly, depleting microglia induced a significant increase in the mRNA expression level of anti-inflammatory factors TGF-β1, Arg1, IL-10, IL-4, and Ym1 as well as a significant decline of pro-inflammatory factors TNF-α, iNOS, and IL-1β 3 days after stroke. CONCLUSIONS These results suggest that activated microglia is an important modulator of the brain's inflammatory response in stroke, contributing to neurological deficit and infarct expansion. Modulation of the inflammatory response through the elimination of microglia at a precise time point may be a promising therapeutic approach for the treatment of cerebral ischemia.
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Affiliation(s)
- Ting Li
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Jin Zhao
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Wenguang Xie
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Wanru Yuan
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Jing Guo
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Shengru Pang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China
| | - Wen-Biao Gan
- Molecular Neurobiology Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, 10016, USA.
| | - Diego Gómez-Nicola
- Centre for Biological Sciences, University of Southampton, South Lab and Path Block, Mail Point 840 LD80C, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.
| | - Shengxiang Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, Gansu, 730000, People's Republic of China.
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70
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Clayton K, Delpech JC, Herron S, Iwahara N, Ericsson M, Saito T, Saido TC, Ikezu S, Ikezu T. Plaque associated microglia hyper-secrete extracellular vesicles and accelerate tau propagation in a humanized APP mouse model. Mol Neurodegener 2021; 16:18. [PMID: 33752701 PMCID: PMC7986521 DOI: 10.1186/s13024-021-00440-9] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/03/2021] [Indexed: 01/09/2023] Open
Abstract
Background Recent studies suggest that microglia contribute to tau pathology progression in Alzheimer’s disease. Amyloid plaque accumulation transforms microglia, the primary innate immune cells in the brain, into neurodegenerative microglia (MGnD), which exhibit enhanced phagocytosis of plaques, apoptotic neurons and dystrophic neurites containing aggregated and phosphorylated tau (p-tau). It remains unclear how microglia promote disease progression while actively phagocytosing pathological proteins, therefore ameliorating pathology. Methods Adeno-associated virus expressing P301L tau mutant (AAV-P301L-tau) was stereotaxically injected into the medial entorhinal cortex (MEC) in C57BL/6 (WT) and humanized APP mutant knock-in homozygote (AppNL-G-F) mice at 5 months of age. Mice were fed either chow containing a colony stimulating factor-1 receptor inhibitor (PLX5622) or control chow from 4 to 6 months of age to test the effect of microglia depletion. Animals were tested at 6 months of age for immunofluorescence, biochemistry, and FACS of microglia. In order to monitor microglial extracellular vesicle secretion in vivo, a novel lentiviral EV reporter system was engineered to express mEmerald-CD9 (mE-CD9) specifically in microglia, which was injected into the same region of MEC. Results Expressing P301L tau mutant in the MEC induced tau propagation to the granule cell layer of the hippocampal dentate gyrus, which was significantly exacerbated in AppNL-G-F mice compared to WT control mice. Administration of PLX5622 depleted nearly all microglia in mouse brains and dramatically reduced propagation of p-tau in WT and to a greater extent in AppNL-G-F mice, although it increased plaque burden and plaque-associated p-tau+ dystrophic neurites. Plaque-associated MGnD microglia strongly expressed an EV marker, tumor susceptibility gene 101, indicative of heightened synthesis of EVs. Intracortical injection of mE-CD9 lentivirus successfully induced microglia-specific expression of mE-CD9+ EV particles, which were significantly enhanced in Mac2+ MGnD microglia compared to Mac2− homeostatic microglia. Finally, consecutive intracortical injection of mE-CD9 lentivirus and AAV-P301L-tau into AppNL-G-F mice revealed encapsulation of p-tau in microglia-specific mE-CD9+ EVs as determined by super-resolution microscopy and immuno-electron microscopy. Discussion Our findings suggest that MGnD microglia hyper-secrete p-tau+ EVs while compacting Aβ plaques and clearing NP tau, which we propose as a novel mechanistic link between amyloid plaque deposition and exacerbation of tau propagation in AppNL-G-F mice. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-021-00440-9.
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Affiliation(s)
- Kevin Clayton
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Jean Christophe Delpech
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Shawn Herron
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Naotoshi Iwahara
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Maria Ericsson
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Takashi Saito
- Department of Neurocognitive Science, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.,Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Seiko Ikezu
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Tsuneya Ikezu
- Departments of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA. .,Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA. .,Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA.
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71
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Neuroinflammatory changes of the normal brain tissue in cured mice following combined radiation and anti-PD-1 blockade therapy for glioma. Sci Rep 2021; 11:5057. [PMID: 33658642 PMCID: PMC7930115 DOI: 10.1038/s41598-021-84600-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 02/11/2021] [Indexed: 12/16/2022] Open
Abstract
The efficacy of combining radiation therapy with immune checkpoint inhibitor blockade to treat brain tumors is currently the subject of multiple investigations and holds significant therapeutic promise. However, the long-term effects of this combination therapy on the normal brain tissue are unknown. Here, we examined mice that were intracranially implanted with murine glioma cell line and became long-term survivors after treatment with a combination of 10 Gy cranial irradiation (RT) and anti-PD-1 checkpoint blockade (aPD-1). Post-mortem analysis of the cerebral hemisphere contralateral to tumor implantation showed complete abolishment of hippocampal neurogenesis, but neural stem cells were well preserved in subventricular zone. In addition, we observed a drastic reduction in the number of mature oligodendrocytes in the subcortical white matter. Importantly, this observation was evident specifically in the combined (RT + aPD-1) treatment group but not in the single treatment arm of either RT alone or aPD-1 alone. Elimination of microglia with a small molecule inhibitor of colony stimulated factor-1 receptor (PLX5622) prevented the loss of mature oligodendrocytes. These results identify for the first time a unique pattern of normal tissue changes in the brain secondary to combination treatment with radiotherapy and immunotherapy. The results also suggest a role for microglia as key mediators of the adverse treatment effect.
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72
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Gaidhani N, Tucci FC, Kem WR, Beaton G, Uteshev VV. Therapeutic efficacy of α7 ligands after acute ischaemic stroke is linked to conductive states of α7 nicotinic ACh receptors. Br J Pharmacol 2021; 178:1684-1704. [PMID: 33496352 DOI: 10.1111/bph.15392] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/22/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Targeting α7 nicotinic ACh receptors (nAChRs) in neuroinflammatory disorders including acute ischaemic stroke holds significant therapeutic promise. However, therapeutically relevant signalling mechanisms remain unidentified. Activation of neuronal α7 nAChRs triggers ionotropic signalling, but there is limited evidence for it in immunoglial tissues. The α7 ligands which are effective in reducing acute ischaemic stroke damage promote α7 ionotropic activity, suggesting a link between their therapeutic effects for treating acute ischaemic stroke and activation of α7 conductive states. EXPERIMENTAL APPROACH This hypothesis was tested using a transient middle cerebral artery occlusion (MCAO) model of acute ischaemic stroke, NS6740, a known selective non-ionotropic agonist of α7 nAChRs and 4OH-GTS-21, a partial α7 agonist. NS6740-like ligands exhibiting low efficacy/potency for ionotropic activity will be referred to as non-ionotropic agonists or "metagonists". KEY RESULTS 4OH-GTS-21, used as a positive control, significantly reduced neurological deficits and brain injury after MCAO as compared to vehicle and NS6740. By contrast, NS6740 was ineffective in identical assays and reversed the effects of 4OH-GTS-21 when these compounds were co-applied. Electrophysiological recordings from acute hippocampal slices obtained from NS6740-injected animals demonstrated its remarkable brain availability and protracted effects on α7 nAChRs as evidenced by sustained (>8 h) alterations in α7 ionotropic responsiveness. CONCLUSION AND IMPLICATIONS These results suggest that α7 ionotropic activity may be obligatory for therapeutic efficacy of α7 ligands after acute ischaemic stroke yet, highlight the potential for selective application of α7 ligands to disease states based on their mode of receptor activation.
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Affiliation(s)
- Nikhil Gaidhani
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Fabio C Tucci
- Epigen Biosciences, Inc., San Diego, California, USA
| | - William R Kem
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Graham Beaton
- Epigen Biosciences, Inc., San Diego, California, USA
| | - Victor V Uteshev
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
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73
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Crews FT, Zou J, Coleman LG. Extracellular microvesicles promote microglia-mediated pro-inflammatory responses to ethanol. J Neurosci Res 2021; 99:1940-1956. [PMID: 33611821 PMCID: PMC8451840 DOI: 10.1002/jnr.24813] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022]
Abstract
Alcohol use disorder (AUD) pathology features pro-inflammatory gene induction and microglial activation. The underlying cellular processes that promote this activation remain unclear. Previously considered cellular debris, extracellular vesicles (EVs) have emerged as mediators of inflammatory signaling in several disease states. We investigated the role of microvesicles (MVs, 50 nm-100 µm diameter EVs) in pro-inflammatory and microglial functional gene expression using primary organotypic brain slice culture (OBSC). Ethanol caused a unique immune gene signature that featured: temporal induction of pro-inflammatory TNF-α and IL-1β, reduction of homeostatic microglia state gene Tmem119, progressive increases in purinergic receptor P2RY12 and the microglial inhibitory fractalkine receptor CX3CR1, an increase in the microglial presynaptic gene C1q, and a reduction in the phagocytic gene TREM2. MV signaling was implicated in this response as reduction of MV secretion by imipramine blocked pro-inflammatory TNF-α and IL-1β induction by ethanol, and ethanol-conditioned MVs (EtOH-MVs) reproduced the ethanol-associated immune gene signature in naïve OBSC slices. Depletion of microglia prior to ethanol treatment prevented pro-inflammatory activity of EtOH-MVs, as did incubation of EtOH-MVs with the HMGB1 inhibitor glycyrrhizin. Ethanol caused HMGB1 secretion from cultured BV2 microglia in MVs through activation of PI3 kinase. In summary, these studies find MVs modulate pro-inflammatory gene induction and microglial activation changes associated with ethanol. Thus, MVs may represent a novel therapeutic target to reduce neuroinflammation in the setting of alcohol abuse or other diseases that feature a neuroimmune component. [Correction added on 5 April 2021, after first online publication: The copyright line was changed.].
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Affiliation(s)
- Fulton T Crews
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA.,Department of Pharmacology, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA.,Department of Psychiatry, The University of North Carolina, School of Medicine, Chapel Hill, NC, USA
| | - Jian Zou
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA
| | - Leon G Coleman
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA.,Department of Pharmacology, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA
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74
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Zhang B, Ran Y, Wu S, Zhang F, Huang H, Zhu C, Zhang S, Zhang X. Inhibition of Colony Stimulating Factor 1 Receptor Suppresses Neuroinflammation and Neonatal Hypoxic-Ischemic Brain Injury. Front Neurol 2021; 12:607370. [PMID: 33679579 PMCID: PMC7930561 DOI: 10.3389/fneur.2021.607370] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/28/2021] [Indexed: 12/17/2022] Open
Abstract
Hypoxic-ischemic (HI) brain injury is a major cause of neonatal death or lifetime disability without widely accepted effective pharmacological treatments. It has been shown that the survival of microglia requires colony-stimulating factor 1 receptor (CSF1R) signaling and microglia participate in neonatal HI brain injury. We therefore hypothesize that microglia depletion during a HI insult period could reduce immature brain injury. In this study, CD1 mouse pups were treated with a CSF1R inhibitor (PLX3397, 25 mg/kg/daily) or a vehicle from postnatal day 4 to day 11 (P4-11), and over 90% of total brain microglia were deleted at P9. Unilateral hemisphere HI injury was induced at P9 by permanently ligating the left common carotid arteries and exposing the pups to 10% oxygen for 30 min to produce moderate left hemisphere injury. We found that the PLX3397 treatment reduced HI brain injury by 46.4%, as evaluated by the percentage of brain infarction at 48 h after HI. Furthermore, CSF1R inhibition suppressed the infiltration of neutrophils (69.7% reduction, p = 0.038), macrophages (77.4% reduction, p = 0.009), and T cells (72.9% reduction, p = 0.008) to the brain, the production of cytokines and chemokines (such as CCL12, CCL6, CCL21, CCL22, CCL19, IL7, CD14, and WISP-1), and reduced neuronal apoptosis as indicated by active caspase-3 labeled cells at 48 h after HI (615.20 ± 156.84/mm2 vs. 1,205.00 ± 99.15/mm2, p = 0.013). Our results suggest that CSF1R inhibition suppresses neuroinflammation and neonatal brain injury after acute cerebral hypoxia-ischemia in neonatal mice.
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Affiliation(s)
- Bohao Zhang
- Henan Key Laboratory of Child Brain Injury, Institute of Neuroscience and Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Center of Advanced Analysis & Gene Sequencing, Zhengzhou University, Zhengzhou, China
| | - Yunwei Ran
- Medical Research Center, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Siting Wu
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Fang Zhang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Huachen Huang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Changlian Zhu
- Henan Key Laboratory of Child Brain Injury, Institute of Neuroscience and Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,Department of Clinical Neuroscience, Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Shusheng Zhang
- Center of Advanced Analysis & Gene Sequencing, Zhengzhou University, Zhengzhou, China
| | - Xiaoan Zhang
- Henan Key Laboratory of Child Brain Injury, Institute of Neuroscience and Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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75
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Lee P. Electrodiffusion with Calcium-Activated Potassium Channels in Dendritic Spine. Bull Math Biol 2021; 83:30. [PMID: 33594481 DOI: 10.1007/s11538-020-00854-4] [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: 08/29/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
We investigate calcium signaling feedback through calcium-activated potassium channels of a dendritic spine by applying the immersed boundary method with electrodiffusion. We simulate the stochastic gating of such ion channels and the resulting spatial distribution of concentration, current, and membrane voltage within the dendritic spine. In this simulation, the permeability to ionic flow across the membrane is regulated by the amplitude of chemical potential barriers. With spatially localized ion channels, chemical potential barriers are locally and stochastically regulated. This regulation represents the ion channel gating with multiple subunits, the open and closed states governed by a continuous-time Markov process. The model simulation recapitulates an inhibitory action on voltage-sensitive calcium channels by the calcium-activated potassium channels in a stochastic manner as a non-local feedback loop. The model predicts amplified calcium influx with more closely placed channel complexes, proposing a potential mechanism of differential calcium handling by channel distributions. This work provides a foundation for future computer simulation studies of dendritic spine motility and structural plasticity.
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Affiliation(s)
- Pilhwa Lee
- Department of Mathematics, Morgan State University, Baltimore, MD, USA.
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76
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Verboon LN, Patel HC, Greenhalgh AD. The Immune System's Role in the Consequences of Mild Traumatic Brain Injury (Concussion). Front Immunol 2021; 12:620698. [PMID: 33679762 PMCID: PMC7928307 DOI: 10.3389/fimmu.2021.620698] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/25/2021] [Indexed: 12/14/2022] Open
Abstract
Mild traumatic brain injury (mild TBI), often referred to as concussion, is the most common form of TBI and affects millions of people each year. A history of mild TBI increases the risk of developing emotional and neurocognitive disorders later in life that can impact on day to day living. These include anxiety and depression, as well as neurodegenerative conditions such as chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD). Actions of brain resident or peripherally recruited immune cells are proposed to be key regulators across these diseases and mood disorders. Here, we will assess the impact of mild TBI on brain and patient health, and evaluate the recent evidence for immune cell involvement in its pathogenesis.
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Affiliation(s)
- Laura N. Verboon
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, United Kingdom
| | - Hiren C. Patel
- Division of Cardiovascular Sciences, Salford Royal National Health Service Foundation Trust, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance National Health Service Group, University of Manchester, Manchester, United Kingdom
| | - Andrew D. Greenhalgh
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, School of Biological Sciences, The University of Manchester, Manchester, United Kingdom
- Geoffrey Jefferson Brain Research Centre, The Manchester Academic Health Science Centre, Northern Care Alliance National Health Service Group, University of Manchester, Manchester, United Kingdom
- Lydia Becker Institute of Immunology and Inflammation, The University of Manchester, Manchester, United Kingdom
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77
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Yegla B, Boles J, Kumar A, Foster TC. Partial microglial depletion is associated with impaired hippocampal synaptic and cognitive function in young and aged rats. Glia 2021; 69:1494-1514. [PMID: 33586813 DOI: 10.1002/glia.23975] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/11/2022]
Abstract
The role of microglia in mediating age-related changes in cognition and hippocampal synaptic function was examined by microglial depletion and replenishment using PLX3397. We observed age-related differences in microglial number and morphology, as well as increased Iba-1 expression, indicating microglial activation. PLX3397 treatment decreased microglial number, with aged rats exhibiting the lowest density. Young rats exhibited increased expression of pro-inflammatory cytokines during depletion and repopulation and maintenance of Iba-1 levels despite reduced microglial number. For aged rats, several cytokines increased with depletion and recovered during repopulation; however, aged rats did not fully recover microglial cell number or Iba-1 expression during repopulation, with a recovery comparable to young control levels rather than aged controls. Hippocampal CA3-CA1 synaptic transmission was impaired with age, and microglial depletion was associated with decreased total synaptic transmission in young and aged rats. A robust decline in N-methyl-d-aspartate-receptor-mediated synaptic transmission arose in young depleted rats specifically. Microglial replenishment normalized depletion-induced synaptic function to control levels; however, recovery of aged animals did not mirror young. Microglial depletion was associated with decreased context-object discrimination memory in both age groups, which recovered with microglial repopulation. Aged rats displayed impaired contextual and cued fear memory, and microglial replenishment did not recover their memory to the level of young. The current study indicates that cognitive function and synaptic transmission benefit from the support of aged microglia and are hindered by removal of these cells. Replenishment of microglia in aging did not ameliorate age-related cognitive impairments or senescent synaptic function.
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Affiliation(s)
- Brittney Yegla
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Jake Boles
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA.,Genetics and Genomics Program, University of Florida, Gainesville, Florida, USA
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Delaney C, Farrell M, Doherty CP, Brennan K, O’Keeffe E, Greene C, Byrne K, Kelly E, Birmingham N, Hickey P, Cronin S, Savvides SN, Doyle SL, Campbell M. Attenuated CSF-1R signalling drives cerebrovascular pathology. EMBO Mol Med 2021; 13:e12889. [PMID: 33350588 PMCID: PMC7863388 DOI: 10.15252/emmm.202012889] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/21/2022] Open
Abstract
Cerebrovascular pathologies occur in up to 80% of cases of Alzheimer's disease; however, the underlying mechanisms that lead to perivascular pathology and accompanying blood-brain barrier (BBB) disruption are still not fully understood. We have identified previously unreported mutations in colony stimulating factor-1 receptor (CSF-1R) in an ultra-rare autosomal dominant condition termed adult-onset leucoencephalopathy with axonal spheroids and pigmented glia (ALSP). Cerebrovascular pathologies such as cerebral amyloid angiopathy (CAA) and perivascular p-Tau were some of the primary neuropathological features of this condition. We have identified two families with different dominant acting alleles with variants located in the kinase region of the CSF-1R gene, which confer a lack of kinase activity and signalling. The protein product of this gene acts as the receptor for 2 cognate ligands, namely colony stimulating factor-1 (CSF-1) and interleukin-34 (IL-34). Here, we show that depletion in CSF-1R signalling induces BBB disruption and decreases the phagocytic capacity of peripheral macrophages but not microglia. CSF-1R signalling appears to be critical for macrophage and microglial activation, and macrophage localisation to amyloid appears reduced following the induction of Csf-1r heterozygosity in macrophages. Finally, we show that endothelial/microglial crosstalk and concomitant attenuation of CSF-1R signalling causes re-modelling of BBB-associated tight junctions and suggest that regulating BBB integrity and systemic macrophage recruitment to the brain may be therapeutically relevant in ALSP and other Alzheimer's-like dementias.
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Affiliation(s)
- Conor Delaney
- Smurfit Institute of GeneticsTrinity College DublinDublin 2Ireland
| | - Michael Farrell
- Department of NeuropathologyBeaumont HospitalDublin 9Ireland
| | - Colin P Doherty
- Department of NeurologyHealth Care CentreSt James's HospitalDublin 8Ireland
- Academic Unit of NeurologyBiomedical Sciences InstituteTrinity College DublinDublin 2Ireland
- FutureNeuro SFI Research CentreRoyal College of Surgeons in IrelandDublinIreland
| | - Kiva Brennan
- Trinity College Institute of NeuroscienceTrinity College Dublin 2Dublin 2Ireland
| | - Eoin O’Keeffe
- Smurfit Institute of GeneticsTrinity College DublinDublin 2Ireland
| | - Chris Greene
- Smurfit Institute of GeneticsTrinity College DublinDublin 2Ireland
| | - Kieva Byrne
- Smurfit Institute of GeneticsTrinity College DublinDublin 2Ireland
| | - Eoin Kelly
- Department of NeurologyHealth Care CentreSt James's HospitalDublin 8Ireland
| | | | | | - Simon Cronin
- Department of MedicineUniversity College CorkCorkIreland
| | - Savvas N Savvides
- Unit for Structural BiologyDepartment of Biochemistry and MicrobiologyGhent UniversityGhentBelgium
- VIB‐UGent Center for Inflammation ResearchGhentBelgium
| | - Sarah L Doyle
- Trinity College Institute of NeuroscienceTrinity College Dublin 2Dublin 2Ireland
| | - Matthew Campbell
- Smurfit Institute of GeneticsTrinity College DublinDublin 2Ireland
- FutureNeuro SFI Research CentreRoyal College of Surgeons in IrelandDublinIreland
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79
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Heinz R, Brandenburg S, Nieminen-Kelhä M, Kremenetskaia I, Boehm-Sturm P, Vajkoczy P, Schneider UC. Microglia as target for anti-inflammatory approaches to prevent secondary brain injury after subarachnoid hemorrhage (SAH). J Neuroinflammation 2021; 18:36. [PMID: 33516246 PMCID: PMC7847606 DOI: 10.1186/s12974-021-02085-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/14/2021] [Indexed: 12/11/2022] Open
Abstract
Background Microglia-driven cerebral spreading inflammation is a key contributor to secondary brain injury after SAH. Genetic depletion or deactivation of microglia has been shown to ameliorate neuronal cell death. Therefore, clinically feasible anti-inflammatory approaches counteracting microglia accumulation or activation are interesting targets for SAH treatment. Here, we tested two different methods of interference with microglia-driven cerebral inflammation in a murine SAH model: (i) inflammatory preconditioning and (ii) pharmacological deactivation. Methods 7T-MRI-controlled SAH was induced by endovascular perforation in four groups of C57Bl/6 mice: (i) Sham-operation, (ii) SAH naïve, (iii) SAH followed by inflammatory preconditioning (LPS intraperitoneally), and (iv) SAH followed by pharmacological microglia deactivation (colony-stimulating factor-1 receptor-antagonist PLX3397 intraperitoneally). Microglia accumulation and neuronal cell death (immuno-fluorescence), as well as activation status (RT-PCR for inflammation-associated molecules from isolated microglia) were recorded at day 4 and 14. Toll-like receptor4 (TLR4) status was analyzed using FACS. Results Following SAH, significant cerebral spreading inflammation occurred. Microglia accumulation and pro-inflammatory gene expression were accompanied by neuronal cell death with a maximum on day 14 after SAH. Inflammatory preconditioning as well as PLX3397-treatment resulted in significantly reduced microglia accumulation and activation as well as neuronal cell death. TLR4 surface expression in preconditioned animals was diminished as a sign for receptor activation and internalization. Conclusions Microglia-driven cerebral spreading inflammation following SAH contributes to secondary brain injury. Two microglia-focused treatment strategies, (i) inflammatory preconditioning with LPS and (ii) pharmacological deactivation with PLX3397, led to significant reduction of neuronal cell death. Increased internalization of inflammation-driving TLR4 after preconditioning leaves less receptor molecules on the cell surface, providing a probable explanation for significantly reduced microglia activation. Our findings support microglia-focused treatment strategies to overcome secondary brain injury after SAH. Delayed inflammation onset provides a valuable clinical window of opportunity. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02085-3.
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Affiliation(s)
- Rebecca Heinz
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Susan Brandenburg
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Melina Nieminen-Kelhä
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Irina Kremenetskaia
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Philipp Boehm-Sturm
- Department of Experimental Neurology and Center for Stroke Research, Charité - Universitätsmedizin Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Vajkoczy
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Experimental Neurology and Center for Stroke Research, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Neurosurgery, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany
| | - Ulf C Schneider
- Experimental Neurosurgery, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany. .,Department of Neurosurgery, Charité - Universitätsmedizin Berlin, 10117, Berlin, Germany.
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80
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Chintamen S, Imessadouene F, Kernie SG. Immune Regulation of Adult Neurogenic Niches in Health and Disease. Front Cell Neurosci 2021; 14:571071. [PMID: 33551746 PMCID: PMC7855589 DOI: 10.3389/fncel.2020.571071] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/23/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia regulate neuronal development during embryogenesis, postnatal development, and in specialized microenvironments of the adult brain. Recent evidence demonstrates that in adulthood, microglia secrete factors which modulate adult hippocampal neurogenesis by inhibiting cell proliferation and survival both in vitro and in vivo, maintaining a balance between cell division and cell death in neurogenic niches. These resident immune cells also shape the nervous system by actively pruning synapses during critical periods of learning and engulfing excess neurons. In neurodegenerative diseases, aberrant microglial activity can impede the proper formation and prevent the development of appropriate functional properties of adult born granule cells. Ablating microglia has been presented as a promising therapeutic approach to alleviate the brain of maladaptive immune response. Here, we review key mechanisms through which the immune system actively shapes neurogenic niches throughout the lifespan of the mammalian brain in both health and disease. We discuss how interactions between immune cells and developing neurons may be leveraged for pharmacological intervention and as a means to preserve adult neurogenesis.
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Affiliation(s)
- Sana Chintamen
- Neurobiology and Behavior, Columbia University Irving Medical Center, New York, NY, United States.,Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
| | - Fatima Imessadouene
- Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
| | - Steven G Kernie
- Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
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81
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Meng J, Ding T, Chen Y, Long T, Xu Q, Lian W, Liu W. LncRNA-Meg3 promotes Nlrp3-mediated microglial inflammation by targeting miR-7a-5p. Int Immunopharmacol 2021; 90:107141. [PMID: 33189612 DOI: 10.1016/j.intimp.2020.107141] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/15/2020] [Accepted: 10/25/2020] [Indexed: 12/13/2022]
Abstract
Recent studies have identified neuroinflammation as a significant contributor to the pathological process of traumatic brain injury (TBI) and as a potentially effective target for treatment. LncRNA maternally expressed gene 3 (Meg3) has further been observed to play a critical role in diverse biological processes, including microglial activation and the inflammatory response. However, its target gene and associated signaling pathway require further elucidation. This study found that lipopolysaccharide + ATP upregulated Meg3, promoted microglia activation, Nlrp3/caspase1 activation and inflammation, and markedly reduced miR-7a-5p. Overexpression of miR-7a-5p attenuated Meg3-induced microglial activation, but not Meg3 expression. Bioinformatic analysis and dual-luciferase assays indicated that Meg3 was a direct target of miR-7a-5p that negatively regulates miR-7a-5p expression. Further, we showed that Meg3 acted as a competing endogenous RNA for miR-7a-5p and induced microglial inflammation by regulating nod-like receptor protein 3 (Nlrp3) expression. Our study thus demonstrates Meg3 regulates microglia inflammation by targeting the miR-7a-5p /Nlrp3 pathway.
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Affiliation(s)
- Jiao Meng
- School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ting Ding
- Department of Anesthesiology and Critical Care Medicine, Peking University First Hospital, Beijing 100034, China
| | - Yuhua Chen
- Department of Neurosurgery, Bijie First People's Hospital, Bijie 551700, China
| | - Tianlin Long
- Department of Neurosurgery, Bijie First People's Hospital, Bijie 551700, China
| | - Quanhua Xu
- Department of Neurosurgery, Bijie First People's Hospital, Bijie 551700, China
| | - Wenqing Lian
- Departmentof Critical Care Medicine, Peking University First Hospital, Beijing 100034, China
| | - Wei Liu
- Department of Neurosurgery, Bijie First People's Hospital, Bijie 551700, China.
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82
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Tan J, Chen SX, Lei QY, Yi SQ, Wu N, Wang YL, Xiao ZJ, Wu H. Mitochonic acid 5 regulates mitofusin 2 to protect microglia. Neural Regen Res 2021; 16:1813-1820. [PMID: 33510088 PMCID: PMC8328753 DOI: 10.4103/1673-5374.306094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Microglial apoptosis is associated with neuroinflammation and no effective strategies are currently available to protect microglia against inflammation-induced apoptosis. Mouse microglial BV-2 cells (5 × 106) were incubated with 10 μg/mL lipopolysaccharides for 12 hours to mimic an inflammatory environment. Then the cells were co-cultured with mitochonic acid 5 (MA-5) for another 12 hours. MA-5 improved the survival of lipopolysaccharide-exposed cells. MA-5 decreased the activity of caspase-3, which is associated with apoptosis. MA-5 reduced the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cells, and increased adenosine triphosphate levels in cells. MA-5 decreased the open state of the mitochondrial permeability transition pore and reduced calcium overload and diffusion of second mitochondria-derived activator of caspase (Smac). MA-5 decreased the expression of apoptosis-related proteins (mitochondrial Smac, cytoplasmic Smac, pro-caspase-3, cleaved-caspase-3, and caspase-9), and increased the levels of anti-apoptotic proteins (Bcl2 and X-linked inhibitor of apoptosis protein), mitochondria-related proteins (mitochondrial fusion protein 2, mitochondrial microtubule-associated proteins 1A/1B light chain 3B II), and autophagy-related proteins (Beclin1, p62 and autophagy related 5). However, MA-5 did not promote mitochondrial homeostasis or decrease microglial apoptosis when Mitofusin 2 expression was silenced. This shows that MA-5 increased Mitofusin 2-related mitophagy, reversed cellular energy production and maintained energy metabolism in BV-2 cells in response to lipopolysaccharide-induced inflammation. These findings indicate that MA-5 may promote the survival of microglial cells via Mitofusin 2-related mitophagy in response to lipopolysaccharide-induced inflammation.
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Affiliation(s)
- Jian Tan
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Shuang-Xi Chen
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Qing-Yun Lei
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Shan-Qing Yi
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Na Wu
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Yi-Lin Wang
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Zi-Jian Xiao
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
| | - Heng Wu
- Department of Neurology, The First Affiliated Hospital of University of South China, Hengyang, Hunan Province, China
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83
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Pimenova AA, Herbinet M, Gupta I, Machlovi SI, Bowles KR, Marcora E, Goate AM. Alzheimer's-associated PU.1 expression levels regulate microglial inflammatory response. Neurobiol Dis 2021; 148:105217. [PMID: 33301878 PMCID: PMC7808757 DOI: 10.1016/j.nbd.2020.105217] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 11/09/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023] Open
Abstract
More than forty loci contribute to genetic risk for Alzheimer's disease (AD). These risk alleles are enriched in myeloid cell enhancers suggesting that microglia, the brain-resident macrophages, contribute to AD risk. We have previously identified SPI1/PU.1, a master regulator of myeloid cell development in the brain and periphery, as a genetic risk factor for AD. Higher expression of SPI1 is associated with increased risk for AD, while lower expression is protective. To investigate the molecular and cellular phenotypes associated with higher and lower expression of PU.1 in microglia, we used stable overexpression and knock-down of PU.1 in BV2, an immortalized mouse microglial cell line. Transcriptome analysis suggests that reduced PU.1 expression suppresses expression of homeostatic genes similar to the disease-associated microglia response to amyloid plaques in mouse models of AD. Moreover, PU.1 knock-down resulted in activation of protein translation, antioxidant action and cholesterol/lipid metabolism pathways with a concomitant decrease of pro-inflammatory gene expression. PU.1 overexpression upregulated and knock-down downregulated phagocytic uptake in BV2 cells independent of the nature of the engulfed material. However, cells with reduced PU.1 expression retained their ability to internalize myelin similar to control albeit with a delay, which aligns with their anti-inflammatory profile. Here we identified several microglial responses that are modulated by PU.1 expression levels and propose that risk association of PU.1 to AD is driven by increased pro-inflammatory response due to increased viability of cells under cytotoxic conditions. In contrast, low expression of PU.1 leads to increased cell death under cytotoxic conditions accompanied by reduced pro-inflammatory signaling that decreased A1 reactive astrocytes signature supporting the protective effect of SPI1 genotype in AD. These findings inform future in vivo validation studies and design of small molecule screens for therapeutic discovery in AD.
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Affiliation(s)
- Anna A Pimenova
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manon Herbinet
- Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ishaan Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, India
| | - Saima I Machlovi
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kathryn R Bowles
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Edoardo Marcora
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alison M Goate
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Ronald M. Loeb Center for Alzheimer's disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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84
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Barnett AM, Crews FT, Coleman LG. Microglial depletion and repopulation: a new era of regenerative medicine? Neural Regen Res 2021; 16:1204-1205. [PMID: 33269777 PMCID: PMC8224128 DOI: 10.4103/1673-5374.300439] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Alexandra M Barnett
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA
| | - Fulton T Crews
- Bowles Center for Alcohol Studies; Department of Pharmacology; Department of Psychiatry, The University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Leon G Coleman
- Bowles Center for Alcohol Studies; Department of Pharmacology, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, NC, USA
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85
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Microglia Elimination Increases Neural Circuit Connectivity and Activity in Adult Mouse Cortex. J Neurosci 2020; 41:1274-1287. [PMID: 33380470 DOI: 10.1523/jneurosci.2140-20.2020] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/16/2020] [Accepted: 12/13/2020] [Indexed: 12/21/2022] Open
Abstract
Microglia have crucial roles in sculpting synapses and maintaining neural circuits during development. To test the hypothesis that microglia continue to regulate neural circuit connectivity in adult brain, we have investigated the effects of chronic microglial depletion, via CSF1R inhibition, on synaptic connectivity in the visual cortex in adult mice of both sexes. We find that the absence of microglia dramatically increases both excitatory and inhibitory synaptic connections to excitatory cortical neurons assessed with functional circuit mapping experiments in acutely prepared adult brain slices. Microglia depletion leads to increased densities and intensities of perineuronal nets. Furthermore, in vivo calcium imaging across large populations of visual cortical neurons reveals enhanced neural activities of both excitatory neurons and parvalbumin-expressing interneurons in the visual cortex following microglia depletion. These changes recover following adult microglia repopulation. In summary, our new results demonstrate a prominent role of microglia in sculpting neuronal circuit connectivity and regulating subsequent functional activity in adult cortex.SIGNIFICANCE STATEMENT Microglia are the primary immune cell of the brain, but recent evidence supports that microglia play an important role in synaptic sculpting during development. However, it remains unknown whether and how microglia regulate synaptic connectivity in adult brain. Our present work shows chronic microglia depletion in adult visual cortex induces robust increases in perineuronal nets, and enhances local excitatory and inhibitory circuit connectivity to excitatory neurons. Microglia depletion increases in vivo neural activities of both excitatory neurons and parvalbumin inhibitory neurons. Our new results reveal new potential avenues to modulate adult neural plasticity by microglia manipulation to better treat brain disorders, such as Alzheimer's disease.
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86
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Lee JH, Kim JY, Noh S, Lee H, Lee SY, Mun JY, Park H, Chung WS. Astrocytes phagocytose adult hippocampal synapses for circuit homeostasis. Nature 2020; 590:612-617. [PMID: 33361813 DOI: 10.1038/s41586-020-03060-3] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023]
Abstract
In the adult hippocampus, synapses are constantly formed and eliminated1,2. However, the exact function of synapse elimination in the adult brain, and how it is regulated, are largely unknown. Here we show that astrocytic phagocytosis3 is important for maintaining proper hippocampal synaptic connectivity and plasticity. By using fluorescent phagocytosis reporters, we find that excitatory and inhibitory synapses are eliminated by glial phagocytosis in the CA1 region of the adult mouse hippocampus. Unexpectedly, we found that astrocytes have a major role in the neuronal activity-dependent elimination of excitatory synapses. Furthermore, mice in which astrocytes lack the phagocytic receptor MEGF10 show a reduction in the elimination of excitatory synapses; as a result, excessive but functionally impaired synapses accumulate. Finally, Megf10-knockout mice show defective long-term synaptic plasticity and impaired formation of hippocampal memories. Together, our data provide strong evidence that astrocytes eliminate unnecessary excitatory synaptic connections in the adult hippocampus through MEGF10, and that this astrocytic function is crucial for maintaining circuit connectivity and thereby supporting cognitive function.
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Affiliation(s)
- Joon-Hyuk Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Ji-Young Kim
- Research Group for Neurovascular Unit, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Seulgi Noh
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.,Research Group for Neural Circuit, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Hyoeun Lee
- Research Group for Neurovascular Unit, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Se Young Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Ji Young Mun
- Research Group for Neural Circuit, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea
| | - Hyungju Park
- Research Group for Neurovascular Unit, Korea Brain Research Institute (KBRI), Daegu, Republic of Korea. .,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.
| | - Won-Suk Chung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
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87
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Suppression of microglial activation and monocyte infiltration ameliorates cerebellar hemorrhage induced-brain injury and ataxia. Brain Behav Immun 2020; 89:400-413. [PMID: 32717406 DOI: 10.1016/j.bbi.2020.07.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 02/07/2023] Open
Abstract
Ataxia, characterized by uncoordinated movement, is often found in patients with cerebellar hemorrhage (CH), leading to long-term disability without effective management. Microglia are among the first responders to CNS insult. Yet the role and mechanism of microglia in cerebellar injury and ataxia after CH are still unknown. Using Ki20227, an inhibitor for colony-stimulating factor 1 receptor which mediates the signaling responsible for the survival of microglia, we determined the impact of microglial depletion on cerebellar injury and ataxia in a murine model of CH. Microglial depletion reduced cerebellar lesion volume and alleviated gait abnormality, motor incoordination, and locomotor dysfunction after CH. Suppression of CH-initiated microglial activation with minocycline ameliorated cerebellum infiltration of monocytes/macrophages, as well as production of proinflammatory cytokines and chemokine C-C motif ligand-2 (CCL-2) that recruits monocytes/macrophages. Furthermore, both minocycline and bindarit, a CCL-2 inhibitor, prevented apoptosis and electrophysiological dysfunction of Purkinje cells, the principal neurons and sole outputs of the cerebellar cortex, and consequently improved ataxia-like motor abnormalities. Our findings suggest a detrimental role of microglia in neuroinflammation and ataxic motor symptoms after CH, and pave a new path to understand the neuroimmune mechanism underlying CH-induced cerebellar ataxia.
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88
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Hardy RA, Rached NA, Jones JA, Archer DR, Hyacinth HI. Role of age and neuroinflammation in the mechanism of cognitive deficits in sickle cell disease. Exp Biol Med (Maywood) 2020; 246:106-120. [PMID: 32962408 DOI: 10.1177/1535370220958011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
IMPACT STATEMENT This study provides crucial information that could be helpful in the development of new or repurposing of existing therapies for the treatment of cognitive deficit in individuals with sickle cell disease (SCD). Its impact is in demonstrating for the first time that neuroinflammation and along with abnormal neuroplasticity are among the underlying mechanism of cognitive and behavioral deficits in SCD and that drugs such as minocycline which targets these pathophysiological mechanisms could be repurposed for the treatment of this life altering complication of SCD.
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Affiliation(s)
- Raven A Hardy
- Neuroscience Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA 30322, USA.,Atlanta Sickle Cell Disease Consortium, Emory University, Atlanta, GA 30322, USA
| | - Noor Abi Rached
- Neuroscience and Behavioral Biology Program, Emory University, Atlanta, GA 30322, USA
| | - Jayre A Jones
- Aflac Cancer and Blood Disorder Center, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.,Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
| | - David R Archer
- Atlanta Sickle Cell Disease Consortium, Emory University, Atlanta, GA 30322, USA.,Aflac Cancer and Blood Disorder Center, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.,Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
| | - Hyacinth I Hyacinth
- Neuroscience Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA 30322, USA.,Atlanta Sickle Cell Disease Consortium, Emory University, Atlanta, GA 30322, USA.,Aflac Cancer and Blood Disorder Center, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA.,Department of Pediatrics, Emory University, Atlanta, GA 30322, USA
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89
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Hohsfield LA, Najafi AR, Ghorbanian Y, Soni N, Hingco EE, Kim SJ, Jue AD, Swarup V, Inlay MA, Green KN. Effects of long-term and brain-wide colonization of peripheral bone marrow-derived myeloid cells in the CNS. J Neuroinflammation 2020; 17:279. [PMID: 32951604 PMCID: PMC7504855 DOI: 10.1186/s12974-020-01931-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/17/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Microglia, the primary resident myeloid cells of the brain, play critical roles in immune defense by maintaining tissue homeostasis and responding to injury or disease. However, microglial activation and dysfunction has been implicated in a number of central nervous system (CNS) disorders, thus developing tools to manipulate and replace these myeloid cells in the CNS is of therapeutic interest. METHODS Using whole body irradiation, bone marrow transplant, and colony-stimulating factor 1 receptor inhibition, we achieve long-term and brain-wide (~ 80%) engraftment and colonization of peripheral bone marrow-derived myeloid cells (i.e., monocytes) in the brain parenchyma and evaluated the long-term effects of their colonization in the CNS. RESULTS Here, we identify a monocyte signature that includes an upregulation in Ccr1, Ms4a6b, Ms4a6c, Ms4a7, Apobec1, Lyz2, Mrc1, Tmem221, Tlr8, Lilrb4a, Msr1, Nnt, and Wdfy1 and a downregulation of Siglech, Slc2a5, and Ccl21a/b. We demonstrate that irradiation and long-term (~ 6 months) engraftment of the CNS by monocytes induces brain region-dependent alterations in transcription profiles, astrocytes, neuronal structures, including synaptic components, and cognition. Although our results show that microglial replacement with peripherally derived myeloid cells is feasible and that irradiation-induced changes can be reversed by the replacement of microglia with monocytes in the hippocampus, we also observe that brain-wide engraftment of peripheral myeloid cells (relying on irradiation) can result in cognitive and synaptic deficits. CONCLUSIONS These findings provide insight into better understanding the role and complexity of myeloid cells in the brain, including their regulation of other CNS cells and functional outcomes.
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Affiliation(s)
- Lindsay A Hohsfield
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Allison R Najafi
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Yasamine Ghorbanian
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, 92697, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, 92697, USA
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Edna E Hingco
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Sung Jin Kim
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Ayer Darling Jue
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Vivek Swarup
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA
| | - Mathew A Inlay
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, 92697, USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA, 92697, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, 3208 Biological Sciences III, Irvine, CA, 92697-4545, USA.
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90
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Li Y, Ritzel RM, Khan N, Cao T, He J, Lei Z, Matyas JJ, Sabirzhanov B, Liu S, Li H, Stoica BA, Loane DJ, Faden AI, Wu J. Delayed microglial depletion after spinal cord injury reduces chronic inflammation and neurodegeneration in the brain and improves neurological recovery in male mice. Am J Cancer Res 2020; 10:11376-11403. [PMID: 33052221 PMCID: PMC7545988 DOI: 10.7150/thno.49199] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 09/02/2020] [Indexed: 12/15/2022] Open
Abstract
Neuropsychological deficits, including impairments in learning and memory, occur after spinal cord injury (SCI). In experimental SCI models, we and others have reported that such changes reflect sustained microglia activation in the brain that is associated with progressive neurodegeneration. In the present study, we examined the effect of pharmacological depletion of microglia on posttraumatic cognition, depressive-like behavior, and brain pathology after SCI in mice. Methods: Young adult male C57BL/6 mice were subjected to moderate/severe thoracic spinal cord contusion. Microglial depletion was induced with the colony-stimulating factor 1 receptor (CSF1R) antagonist PLX5622 administered starting either 3 weeks before injury or one day post-injury and continuing through 6 weeks after SCI. Neuroinflammation in the injured spinal cord and brain was assessed using flow cytometry and NanoString technology. Neurological function was evaluated using a battery of neurobehavioral tests including motor function, cognition, and depression. Lesion volume and neuronal counts were quantified by unbiased stereology. Results: Flow cytometry analysis demonstrated that PLX5622 pre-treatment significantly reduced the number of microglia, as well as infiltrating monocytes and neutrophils, and decreased reactive oxygen species production in these cells from injured spinal cord at 2-days post-injury. Post-injury PLX5622 treatment reduced both CD45int microglia and CD45hi myeloid counts at 7-days. Following six weeks of PLX5622 treatment, there were substantial changes in the spinal cord and brain transcriptomes, including those involved in neuroinflammation. These alterations were associated with improved neuronal survival in the brain and neurological recovery. Conclusion: These findings indicate that pharmacological microglia-deletion reduces neuroinflammation in the injured spinal cord and brain, improving recovery of cognition, depressive-like behavior, and motor function.
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91
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Green KN, Crapser JD, Hohsfield LA. To Kill a Microglia: A Case for CSF1R Inhibitors. Trends Immunol 2020; 41:771-784. [PMID: 32792173 PMCID: PMC7484341 DOI: 10.1016/j.it.2020.07.001] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 07/02/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022]
Abstract
Microglia, the brain's immune sentinels, have garnered much attention in recent years. Researchers have begun to identify the manifold roles that these cells play in the central nervous system (CNS), and this work has been greatly facilitated by microglial depletion paradigms. The varying degrees of spatiotemporal manipulation afforded by such techniques allow microglial ablation before, during, and/or following insult, injury, or disease. We review the major methods of microglial depletion, including toxin-based, genetic, and pharmacological approaches, which differ in key factors including depletion onset, duration, and off-target effects. We conclude that pharmacological CSF1R inhibitors afford the most extensive versatility in manipulating microglia, making them ideal candidates for future studies investigating microglial function in health and disease.
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Affiliation(s)
- Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA.
| | - Joshua D Crapser
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Lindsay A Hohsfield
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
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92
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Du X, Xu Y, Chen S, Fang M. Inhibited CSF1R Alleviates Ischemia Injury via Inhibition of Microglia M1 Polarization and NLRP3 Pathway. Neural Plast 2020; 2020:8825954. [PMID: 32908485 PMCID: PMC7474788 DOI: 10.1155/2020/8825954] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/31/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022] Open
Abstract
Ischemia cerebral stroke is one of the common neurological diseases with severe inflammatory response and neuron death. The inhibition of colony-stimulating factor 1 receptor (CSF1R) which especially expressed in microglia/macrophage exerted neuroprotection in stroke. However, the underlying neuroinflammatory regulation effects of CSF1R in ischemia stroke are not clear. In this study, cerebral ischemia stroke mice model was established. The C57/B6J mice were administered with Ki20227, a CSF1R inhibitor, by gavage for 7 consecutive days (0.002 mg/kg/day) before modeling. The Rota-Rod test and neurobehavioral score test were investigated to assess neurobehavioral functions. The area of infarction was assessed by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. The mRNA expressions of M1/M2 microglia markers were evaluated by real-time PCR. Immunofluorescence and Western blot were utilized to detect the changes of Iba1 and NLRP3 pathway proteins. Results showed that neurobehavioral function improvement was demonstrated by an increased stay time on the Rota-Rod test and a decreased neurobehavioral score in the Ki20227 treatment group. The area of infarction reduced in Ki20227 group when compared to the stroke group. Moreover, the mRNA expression of M1 microglia markers (TNF-α and iNOS) decreased while M2 microglia markers (IL-10 and Arg-1) increased. Meanwhile, compared to the stroke and stroke+PBS group, Ki20227 administration downregulated the expression of NLRP3, active caspase 1, and NF-κB protein in the ischemia penumbra of Ki20227 treatment group mice. In short, the CSF1R inhibitor, Ki20227, played vital neuroprotective roles in ischemia cerebral stroke mice, and the mechanisms may be via inhibiting microglia M1 polarization and NLRP3 inflammasome pathway activation. Our study provides a potential new target for the treatment of ischemic stroke injury.
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Affiliation(s)
- Xiaoxue Du
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, 310006 Zhejiang, China
- Translational Medicine Center, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, 310006 Zhejiang, China
| | - Yuzhen Xu
- Department of Neurology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Shijia Chen
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, 310006 Zhejiang, China
| | - Marong Fang
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, 310006 Zhejiang, China
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93
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Crapser JD, Ochaba J, Soni N, Reidling JC, Thompson LM, Green KN. Microglial depletion prevents extracellular matrix changes and striatal volume reduction in a model of Huntington's disease. Brain 2020; 143:266-288. [PMID: 31848580 DOI: 10.1093/brain/awz363] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/22/2019] [Accepted: 10/01/2019] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease is associated with a reactive microglial response and consequent inflammation. To address the role of these cells in disease pathogenesis, we depleted microglia from R6/2 mice, a rapidly progressing model of Huntington's disease marked by behavioural impairment, mutant huntingtin (mHTT) accumulation, and early death, through colony-stimulating factor 1 receptor inhibition (CSF1Ri) with pexidartinib (PLX3397) for the duration of disease. Although we observed an interferon gene signature in addition to downregulated neuritogenic and synaptic gene pathways with disease, overt inflammation was not evident by microglial morphology or cytokine transcript levels in R6/2 mice. Nonetheless, CSF1Ri-induced microglial elimination reduced or prevented disease-related grip strength and object recognition deficits, mHTT accumulation, astrogliosis, and striatal volume loss, the latter of which was not associated with reductions in cell number but with the extracellular accumulation of chondroitin sulphate proteoglycans (CSPGs)-a primary component of glial scars. A concurrent loss of proteoglycan-containing perineuronal nets was also evident in R6/2 mice, and microglial elimination not only prevented this but also strikingly increased perineuronal nets in the brains of naïve littermates, suggesting a new role for microglia as homeostatic regulators of perineuronal net formation and integrity.
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Affiliation(s)
- Joshua D Crapser
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Joseph Ochaba
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Jack C Reidling
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA.,Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
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94
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Willis EF, MacDonald KPA, Nguyen QH, Garrido AL, Gillespie ER, Harley SBR, Bartlett PF, Schroder WA, Yates AG, Anthony DC, Rose-John S, Ruitenberg MJ, Vukovic J. Repopulating Microglia Promote Brain Repair in an IL-6-Dependent Manner. Cell 2020; 180:833-846.e16. [PMID: 32142677 DOI: 10.1016/j.cell.2020.02.013] [Citation(s) in RCA: 271] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 11/21/2019] [Accepted: 02/05/2020] [Indexed: 12/20/2022]
Abstract
Cognitive dysfunction and reactive microglia are hallmarks of traumatic brain injury (TBI), yet whether these cells contribute to cognitive deficits and secondary inflammatory pathology remains poorly understood. Here, we show that removal of microglia from the mouse brain has little effect on the outcome of TBI, but inducing the turnover of these cells through either pharmacologic or genetic approaches can yield a neuroprotective microglial phenotype that profoundly aids recovery. The beneficial effects of these repopulating microglia are critically dependent on interleukin-6 (IL-6) trans-signaling via the soluble IL-6 receptor (IL-6R) and robustly support adult neurogenesis, specifically by augmenting the survival of newborn neurons that directly support cognitive function. We conclude that microglia in the mammalian brain can be manipulated to adopt a neuroprotective and pro-regenerative phenotype that can aid repair and alleviate the cognitive deficits arising from brain injury.
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Affiliation(s)
- Emily F Willis
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Kelli P A MacDonald
- Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Quan H Nguyen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Adahir Labrador Garrido
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Ellen R Gillespie
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Samuel B R Harley
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Perry F Bartlett
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Wayne A Schroder
- Department of Immunology, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; School of Environment and Science, Griffith University, QLD, Brisbane, Australia
| | - Abi G Yates
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Daniel C Anthony
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Stefan Rose-John
- Biochemisches Institut, Christian Albrechts Universität Kiel, Kiel, Germany
| | - Marc J Ruitenberg
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Jana Vukovic
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
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95
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Crapser JD, Spangenberg EE, Barahona RA, Arreola MA, Hohsfield LA, Green KN. Microglia facilitate loss of perineuronal nets in the Alzheimer's disease brain. EBioMedicine 2020; 58:102919. [PMID: 32745992 PMCID: PMC7399129 DOI: 10.1016/j.ebiom.2020.102919] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Microglia, the brain's principal immune cell, are increasingly implicated in Alzheimer's disease (AD), but the molecular interfaces through which these cells contribute to amyloid beta (Aβ)-related neurodegeneration are unclear. We recently identified microglial contributions to the homeostatic and disease-associated modulation of perineuronal nets (PNNs), extracellular matrix structures that enwrap and stabilize neuronal synapses, but whether PNNs are altered in AD remains controversial. METHODS Extensive histological analysis was performed on male and female 5xFAD mice at 4, 8, 12, and 18 months of age to assess plaque burden, microgliosis, and PNNs. Findings were validated in postmortem AD tissue. The role of neuroinflammation in PNN loss was investigated via LPS treatment, and the ability to prevent or rescue disease-related reductions in PNNs was assessed by treating 5xFAD and 3xTg-AD model mice with colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 to deplete microglia. FINDINGS Utilizing the 5xFAD mouse model and human cortical tissue, we report that PNNs are extensively lost in AD in proportion to plaque burden. Activated microglia closely associate with and engulf damaged nets in the 5xFAD brain, and inclusions of PNN material are evident in mouse and human microglia, while aggrecan, a critical PNN component, deposits within human dense-core plaques. Disease-associated reductions in parvalbumin (PV)+ interneurons, frequently coated by PNNs, are preceded by PNN coverage and integrity impairments, and similar phenotypes are elicited in wild-type mice following microglial activation with LPS. Chronic pharmacological depletion of microglia prevents 5xFAD PNN loss, with similar results observed following depletion in aged 3xTg-AD mice, and this occurs despite plaque persistence. INTERPRETATION We conclude that phenotypically altered microglia facilitate plaque-dependent PNN loss in the AD brain. FUNDING The NIH (NIA, NINDS) and the Alzheimer's Association.
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Affiliation(s)
- Joshua D Crapser
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | | | - Rocio A Barahona
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Miguel A Arreola
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Lindsay A Hohsfield
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA.
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96
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Hao T, Du X, Yang S, Zhang Y, Liang F. Astrocytes-induced neuronal inhibition contributes to depressive-like behaviors during chronic stress. Life Sci 2020; 258:118099. [PMID: 32682917 DOI: 10.1016/j.lfs.2020.118099] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/01/2020] [Accepted: 07/10/2020] [Indexed: 01/09/2023]
Abstract
Although emerging evidence has highlighted the heterogeneities of astrocytes under physiological versus pathological conditions, little is known regarding these processes in different brain regions during stress. Thus, the present study established a mouse model of chronic social defeat stress (CSDS) and isolated astrocytes from the medial prefrontal cortex (mPFC) and hippocampus. The results revealed dramatic A1-specific (neurotoxic phenotype) astrocytic responses, depressive-like behaviors, and significant inhibition of neuronal activities in both the mPFC and hippocampus according to electrophysiological data. Subsequently, astrocytes in the mPFC and hippocampus of CSDS mice were suppressed and this reversed the astrocytic responses and rescued depressive-like behaviors. Furthermore, when astrocytes were activated in the mPFC and hippocampus in healthy mice, there was a non-specific phenotypic activation of astrocytes in the absence of depressive-like behaviors. Next, microglia were depleted and the mice subsequently performed in the CSDS model; this reduced astrocyte responses and restored depressive-like behaviors. On the other hand, when microglia were depleted but astrocytes were activated in CSDS mice, this abolished the restoration of microglia depletion-induced depressive-like behaviors. Taken together, these results indicate that neuronal inhibition by astrocytes in the mPFC and hippocampus contributed to depressive-like behaviors mediated by activated microglia. This study provides evidence regarding the interaction of microglia and astrocytes during stress and how that relationship can trigger depressive-like behaviors.
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Affiliation(s)
- Tianpao Hao
- Department of Emergency, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Xiaohong Du
- Department of geriatric medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Shen Yang
- Departments of Neurology, Tai'an City Central Hospital, Tai'an 271000, China
| | - Yang Zhang
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Feiyu Liang
- Department of geriatric medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China.
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97
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Fu H, Zhao Y, Hu D, Wang S, Yu T, Zhang L. Depletion of microglia exacerbates injury and impairs function recovery after spinal cord injury in mice. Cell Death Dis 2020; 11:528. [PMID: 32661227 PMCID: PMC7359318 DOI: 10.1038/s41419-020-2733-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 06/18/2020] [Accepted: 06/22/2020] [Indexed: 11/24/2022]
Abstract
The role of microglia in spinal cord injury (SCI) remains ambiguous, partially due to the paucity of efficient methods to discriminate these resident microglia with blood-derived monocytes/macrophages. Here, we used pharmacological treatments to specifically eliminate microglia and subsequently to investigate the response of microglia after SCI in mice. We showed that treatment with colony stimulating factor 1 receptor (CSF1R) inhibitor PLX3397 eliminated ~90% microglia and did not affect other cell types in mouse spinal cord. PLX3397 treatment also induced a strong decrease in microglial proliferation induced by SCI. Depletion of microglia after SCI disrupted glial scar formation, enhanced immune cell infiltrates, reduced neuronal survival, delayed astrocyte repopulation, exacerbated axonal dieback, and impaired locomotor recovery. Therefore, our findings suggest microglia may play a protective role after SCI in mice.
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Affiliation(s)
- Haitao Fu
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China.,Department of Orthopaedics, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yanpeng Zhao
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China
| | - Die Hu
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, China
| | - Song Wang
- School of Medicine, Nankai University, Tianjin, China
| | - Tengbo Yu
- Department of Orthopaedics, The Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Licheng Zhang
- Department of Orthopedics, Chinese PLA General Hospital, Beijing, China.
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98
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Extracellular Vesicles miRNA Cargo for Microglia Polarization in Traumatic Brain Injury. Biomolecules 2020; 10:biom10060901. [PMID: 32545705 PMCID: PMC7356143 DOI: 10.3390/biom10060901] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/06/2020] [Accepted: 06/09/2020] [Indexed: 02/07/2023] Open
Abstract
Traumatic brain injury (TBI) is one of the major causes of death and disability worldwide, and despite its high dissemination, effective pharmacotherapies are lacking. TBI can be divided into two phases: the instantaneous primary mechanical injury, which occurs at the moment of insult, and the delayed secondary injury, which involves a cascade of biological processes that lead to neuroinflammation. Neuroinflammation is a hallmark of both acute and chronic TBI, and it is considered to be one of the major determinants of the outcome and progression of disease. In TBI one of the emerging mechanisms for cell–cell communication involved in the immune response regulation is represented by Extracellular Vesicles (EVs). These latter are produced by all cell types and are considered a fingerprint of their generating cells. Exosomes are the most studied nanosized vesicles and can carry a variety of molecular constituents of their cell of origin, including microRNAs (miRNAs). Several miRNAs have been shown to target key neuropathophysiological pathways involved in TBI. The focus of this review is to analyze exosomes and their miRNA cargo to modulate TBI neuroinflammation providing new strategies for prevent long-term progression of disease.
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99
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Li Y, Cao T, Ritzel RM, He J, Faden AI, Wu J. Dementia, Depression, and Associated Brain Inflammatory Mechanisms after Spinal Cord Injury. Cells 2020; 9:cells9061420. [PMID: 32521597 PMCID: PMC7349379 DOI: 10.3390/cells9061420] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/04/2020] [Accepted: 06/04/2020] [Indexed: 12/28/2022] Open
Abstract
Evaluation of the chronic effects of spinal cord injury (SCI) has long focused on sensorimotor deficits, neuropathic pain, bladder/bowel dysfunction, loss of sexual function, and emotional distress. Although not well appreciated clinically, SCI can cause cognitive impairment including deficits in learning and memory, executive function, attention, and processing speed; it also commonly leads to depression. Recent large-scale longitudinal population-based studies indicate that patients with isolated SCI (without concurrent brain injury) are at a high risk of dementia associated with substantial cognitive impairments. Yet, little basic research has addressed potential mechanisms for cognitive impairment and depression after injury. In addition to contributing to disability in their own right, these changes can adversely affect rehabilitation and recovery and reduce quality of life. Here, we review clinical and experimental work on the complex and varied responses in the brain following SCI. We also discuss potential mechanisms responsible for these less well-examined, important SCI consequences. In addition, we outline the existing and developing therapeutic options aimed at reducing SCI-induced brain neuroinflammation and post-injury cognitive and emotional impairments.
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Affiliation(s)
- Yun Li
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
| | - Tuoxin Cao
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
| | - Rodney M. Ritzel
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
| | - Junyun He
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
| | - Alan I. Faden
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
- University of Maryland Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
| | - Junfang Wu
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, MD 21201, USA; (Y.L.); (T.C.); (R.M.R.); (J.H.); (A.I.F.)
- University of Maryland Center to Advance Chronic Pain Research, University of Maryland, Baltimore, MD 21201, USA
- Correspondence: ; Tel.: +1-410-706-5189
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Microglia depletion fails to abrogate inflammation-induced sickness in mice and rats. J Neuroinflammation 2020; 17:172. [PMID: 32475344 PMCID: PMC7262755 DOI: 10.1186/s12974-020-01832-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/27/2020] [Indexed: 12/14/2022] Open
Abstract
Background Production of inflammatory mediators by reactive microglial cells in the brain is generally considered the primary mechanism underlying the development of symptoms of sickness in response to systemic inflammation. Methods Depletion of microglia was achieved in C57BL/6 mice by chronic oral administration of PLX5622, a specific antagonist of colony stimulating factor-1 receptor, and in rats by a knock-in model in which the diphtheria toxin receptor was expressed under the control of the endogenous fractalkine receptor (CX3CR1) promoter sequence. After successful microglia depletion, mice and rats were injected with a sickness-inducing dose of lipopolysaccharide according to a 2 (depletion vs. control) × 2 (LPS vs. saline) factorial design. Sickness was measured by body weight loss and decreased locomotor activity in rats and mice, and reduced voluntary wheel running in mice. Results Chronic administration of PLX5622 in mice and administration of diphtheria toxin to knock-in rats depleted microglia and peripheral tissue macrophages. However, it did not abrogate the inducible expression of proinflammatory cytokines in the brain in response to LPS and even exacerbated it for some of the cytokines. In accordance with these neuroimmune effects, LPS-induced sickness was not abrogated, rather it was exacerbated when measured by running wheel activity in mice. Conclusions These findings reveal that the sickness-inducing effects of acute inflammation can develop independently of microglia activation.
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