1
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Zha X, Zheng G, Skutella T, Kiening K, Unterberg A, Younsi A. Microglia: a promising therapeutic target in spinal cord injury. Neural Regen Res 2025; 20:454-463. [PMID: 38819048 DOI: 10.4103/nrr.nrr-d-23-02044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/22/2024] [Indexed: 06/01/2024] Open
Abstract
Microglia are present throughout the central nervous system and are vital in neural repair, nutrition, phagocytosis, immunological regulation, and maintaining neuronal function. In a healthy spinal cord, microglia are accountable for immune surveillance, however, when a spinal cord injury occurs, the microenvironment drastically changes, leading to glial scars and failed axonal regeneration. In this context, microglia vary their gene and protein expression during activation, and proliferation in reaction to the injury, influencing injury responses both favorably and unfavorably. A dynamic and multifaceted injury response is mediated by microglia, which interact directly with neurons, astrocytes, oligodendrocytes, and neural stem/progenitor cells. Despite a clear understanding of their essential nature and origin, the mechanisms of action and new functions of microglia in spinal cord injury require extensive research. This review summarizes current studies on microglial genesis, physiological function, and pathological state, highlights their crucial roles in spinal cord injury, and proposes microglia as a therapeutic target.
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Affiliation(s)
- Xiaowei Zha
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Guoli Zheng
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Thomas Skutella
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Karl Kiening
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Andreas Unterberg
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
| | - Alexander Younsi
- Department of Neurosurgery, Heidelberg University Hospital, Heidelberg, Germany
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2
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Lénárt N, Cserép C, Császár E, Pósfai B, Dénes Á. Microglia-neuron-vascular interactions in ischemia. Glia 2024; 72:833-856. [PMID: 37964690 DOI: 10.1002/glia.24487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
Cerebral ischemia is a devastating condition that results in impaired blood flow in the brain leading to acute brain injury. As the most common form of stroke, occlusion of cerebral arteries leads to a characteristic sequence of pathophysiological changes in the brain tissue. The mechanisms involved, and comorbidities that determine outcome after an ischemic event appear to be highly heterogeneous. On their own, the processes leading to neuronal injury in the absence of sufficient blood supply to meet the metabolic demand of the cells are complex and manifest at different temporal and spatial scales. While the contribution of non-neuronal cells to stroke pathophysiology is increasingly recognized, recent data show that microglia, the main immune cells of the central nervous system parenchyma, play previously unrecognized roles in basic physiological processes beyond their inflammatory functions, which markedly change during ischemic conditions. In this review, we aim to discuss some of the known microglia-neuron-vascular interactions assumed to contribute to the acute and delayed pathologies after cerebral ischemia. Because the mechanisms of neuronal injury have been extensively discussed in several excellent previous reviews, here we focus on some recently explored pathways that may directly or indirectly shape neuronal injury through microglia-related actions. These discoveries suggest that modulating gliovascular processes in different forms of stroke and other neurological disorders might have presently unexplored therapeutic potential in combination with neuroprotective and flow restoration strategies.
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Affiliation(s)
- Nikolett Lénárt
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Eszter Császár
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Pósfai
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ádám Dénes
- Momentum Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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3
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Cheng YT, Lett KM, Xu C, Schaffer CB. Three-photon excited fluorescence microscopy enables imaging of blood flow, neural structure and inflammatory response deep into mouse spinal cord in vivo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588110. [PMID: 38617307 PMCID: PMC11014502 DOI: 10.1101/2024.04.04.588110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Nonlinear optical microscopy enables non-invasive imaging in scattering samples with cellular resolution. The spinal cord connects the brain with the periphery and governs fundamental behaviors such as locomotion and somatosensation. Because of dense myelination on the dorsal surface, imaging to the spinal grey matter is challenging, even with two-photon microscopy. Here we show that three-photon excited fluorescence (3PEF) microscopy enables multicolor imaging at depths of up to ~550 μm into the mouse spinal cord, in vivo. We quantified blood flow across vessel types along the spinal vascular network. We then followed the response of neurites and microglia after occlusion of a surface venule, where we observed depth-dependent structural changes in neurites and interactions of perivascular microglia with vessel branches upstream from the clot. This work establishes that 3PEF imaging enables studies of functional dynamics and cell type interactions in the top 550 μm of the murine spinal cord, in vivo.
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Affiliation(s)
- Yu-Ting Cheng
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA
| | - Kawasi M. Lett
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Chris Xu
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Chris B. Schaffer
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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4
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Deng W, Yi P, Xiong Y, Ying J, Lin Y, Dong Y, Wei G, Wang X, Hua F. Gut Metabolites Acting on the Gut-Brain Axis: Regulating the Functional State of Microglia. Aging Dis 2024; 15:480-502. [PMID: 37548933 PMCID: PMC10917527 DOI: 10.14336/ad.2023.0727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/27/2023] [Indexed: 08/08/2023] Open
Abstract
The gut-brain axis is a communication channel that mediates a complex interplay of intestinal flora with the neural, endocrine, and immune systems, linking gut and brain functions. Gut metabolites, a group of small molecules produced or consumed by biochemical processes in the gut, are involved in central nervous system regulation via the highly interconnected gut-brain axis affecting microglia indirectly by influencing the structure of the gut-brain axis or directly affecting microglia function and activity. Accordingly, pathological changes in the central nervous system are connected with changes in intestinal metabolite levels as well as altered microglia function and activity, which may contribute to the pathological process of each neuroinflammatory condition. Here, we discuss the mechanisms by which gut metabolites, for instance, the bile acids, short-chain fatty acids, and tryptophan metabolites, regulate the structure of each component of the gut-brain axis, and explore the important roles of gut metabolites in the central nervous system from the perspective of microglia. At the same time, we highlight the roles of gut metabolites affecting microglia in the pathogenesis of neurodegenerative diseases and neurodevelopmental disorders. Understanding the relationship between microglia, gut microbiota, neuroinflammation, and neurodevelopmental disorders will help us identify new strategies for treating neuropsychiatric disorders.
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Affiliation(s)
- Wenze Deng
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Pengcheng Yi
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Yanhong Xiong
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Jun Ying
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Yue Lin
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Yao Dong
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Gen Wei
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
| | - Xifeng Wang
- Department of Anesthesiology, the First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
| | - Fuzhou Hua
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
- Key Laboratory of Anesthesiology of Jiangxi Province, Nanchang City, Jiangxi, China.
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5
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Halder SK, Sapkota A, Milner R. β1 integrins play a critical role maintaining vascular integrity in the hypoxic spinal cord, particularly in white matter. Acta Neuropathol Commun 2024; 12:45. [PMID: 38509621 PMCID: PMC10953150 DOI: 10.1186/s40478-024-01749-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/24/2024] [Indexed: 03/22/2024] Open
Abstract
Interactions between extracellular matrix (ECM) proteins and β1 integrins play an essential role maintaining vascular integrity in the brain, particularly under vascular remodeling conditions. As blood vessels in the spinal cord are reported to have distinct properties from those in the brain, here we examined the impact of β1 integrin inhibition on spinal cord vascular integrity, both under normoxic conditions, when blood vessels are stable, and during exposure to chronic mild hypoxia (CMH), when extensive vascular remodeling occurs. We found that a function-blocking β1 integrin antibody triggered a small degree of vascular disruption in the spinal cord under normoxic conditions, but under hypoxic conditions, it greatly enhanced (20-fold) vascular disruption, preferentially in spinal cord white matter (WM). This resulted in elevated microglial activation as well as marked loss of myelin integrity and reduced density of oligodendroglial cells. To understand why vascular breakdown is localized to WM, we compared expression levels of major BBB components of WM and grey matter (GM) blood vessels, but this revealed no obvious differences. Interestingly however, hypoxyprobe staining demonstrated that the most severe levels of spinal cord hypoxia induced by CMH occurred in the WM. Analysis of brain tissue revealed a similar preferential vulnerability of WM tracts to show vascular disruption under these conditions. Taken together, these findings demonstrate an essential role for β1 integrins in maintaining vascular integrity in the spinal cord, and unexpectedly, reveal a novel and fundamental difference between WM and GM blood vessels in their dependence on β1 integrin function during hypoxic exposure. Our data support the concept that the preferential WM vulnerability described may be less a result of intrinsic differences in vascular barrier properties between WM and GM, and more a consequence of differences in vascular density and architecture.
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, 92121, San Diego, CA, USA
| | - Arjun Sapkota
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, 92121, San Diego, CA, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, 92121, San Diego, CA, USA.
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6
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Procès A, Alpizar YA, Halliez S, Brône B, Saudou F, Ris L, Gabriele S. Stretch-injury promotes microglia activation with enhanced phagocytic and synaptic stripping activities. Biomaterials 2024; 305:122426. [PMID: 38134473 DOI: 10.1016/j.biomaterials.2023.122426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 11/29/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
Microglial cells, as the primary defense line in the central nervous system, play a crucial role in responding to various mechanical signals that can trigger their activation. Despite extensive research on the impact of chemical signaling on brain cells, the understanding of mechanical signaling in microglia remains limited. To bridge this gap, we subjected microglial cells to a singular mechanical stretch and compared their responses with those induced by lipopolysaccharide treatment, a well-established chemical activator. Here we show that stretching microglial cells leads to their activation, highlighting their significant mechanosensitivity. Stretched microglial cells exhibited distinct features, including elevated levels of Iba1 protein, a denser actin cytoskeleton, and increased persistence in migration. Unlike LPS-treated microglial cells, the secretory profile of chemokines and cytokines remained largely unchanged in response to stretching, except for TNF-α. Intriguingly, a single stretch injury resulted in more compacted chromatin and DNA damage, suggesting potential long-term genomic instabilities in stretched microglia. Using compartmentalized microfluidic chambers with neuronal networks, we observed that stretched microglial cells exhibited enhanced phagocytic and synaptic stripping activities. These findings collectively suggest that stretching events can unlock the immune potential of microglial cells, contributing to the maintenance of brain tissue homeostasis following mechanical injury.
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Affiliation(s)
- Anthony Procès
- Mechanobiology & Biomaterials Group, CIRMAP, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium; Neuroscience Laboratory, Neuroscience Department, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium
| | - Yeranddy A Alpizar
- Neurophysiology Laboratory, BIOMED Research Institute, UHasselt, B-3500, Hasselt, Belgium
| | - Sophie Halliez
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, F-59000, Lille, France
| | - Bert Brône
- Neurophysiology Laboratory, BIOMED Research Institute, UHasselt, B-3500, Hasselt, Belgium
| | - Frédéric Saudou
- Univ. Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neuroscience, F-38000, Grenoble, France
| | - Laurence Ris
- Neuroscience Laboratory, Neuroscience Department, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium
| | - Sylvain Gabriele
- Mechanobiology & Biomaterials Group, CIRMAP, Research Institute for Biosciences, University of Mons, B-7000, Mons, Belgium.
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7
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Elder GA, Gama Sosa MA, De Gasperi R, Perez Garcia G, Perez GM, Abutarboush R, Kawoos U, Zhu CW, Janssen WGM, Stone JR, Hof PR, Cook DG, Ahlers ST. The Neurovascular Unit as a Locus of Injury in Low-Level Blast-Induced Neurotrauma. Int J Mol Sci 2024; 25:1150. [PMID: 38256223 PMCID: PMC10816929 DOI: 10.3390/ijms25021150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Blast-induced neurotrauma has received much attention over the past decade. Vascular injury occurs early following blast exposure. Indeed, in animal models that approximate human mild traumatic brain injury or subclinical blast exposure, vascular pathology can occur in the presence of a normal neuropil, suggesting that the vasculature is particularly vulnerable. Brain endothelial cells and their supporting glial and neuronal elements constitute a neurovascular unit (NVU). Blast injury disrupts gliovascular and neurovascular connections in addition to damaging endothelial cells, basal laminae, smooth muscle cells, and pericytes as well as causing extracellular matrix reorganization. Perivascular pathology becomes associated with phospho-tau accumulation and chronic perivascular inflammation. Disruption of the NVU should impact activity-dependent regulation of cerebral blood flow, blood-brain barrier permeability, and glymphatic flow. Here, we review work in an animal model of low-level blast injury that we have been studying for over a decade. We review work supporting the NVU as a locus of low-level blast injury. We integrate our findings with those from other laboratories studying similar models that collectively suggest that damage to astrocytes and other perivascular cells as well as chronic immune activation play a role in the persistent neurobehavioral changes that follow blast injury.
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Affiliation(s)
- Gregory A. Elder
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA;
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; (M.A.G.S.); (R.D.G.)
- Mount Sinai Alzheimer’s Disease Research Center and the Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (C.W.Z.); (P.R.H.)
| | - Miguel A. Gama Sosa
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; (M.A.G.S.); (R.D.G.)
- General Medical Research Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY 10468, USA
| | - Rita De Gasperi
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; (M.A.G.S.); (R.D.G.)
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA;
| | - Georgina Perez Garcia
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA;
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA;
| | - Gissel M. Perez
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA;
| | - Rania Abutarboush
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical ResearchCommand, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; (R.A.); (U.K.); (S.T.A.)
- The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD 20817, USA
| | - Usmah Kawoos
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical ResearchCommand, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; (R.A.); (U.K.); (S.T.A.)
- The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD 20817, USA
| | - Carolyn W. Zhu
- Mount Sinai Alzheimer’s Disease Research Center and the Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (C.W.Z.); (P.R.H.)
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA;
- Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - William G. M. Janssen
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - James R. Stone
- Department of Radiology and Medical Imaging, University of Virginia, 480 Ray C Hunt Drive, Charlottesville, VA 22903, USA;
| | - Patrick R. Hof
- Mount Sinai Alzheimer’s Disease Research Center and the Ronald M. Loeb Center for Alzheimer’s Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (C.W.Z.); (P.R.H.)
- Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - David G. Cook
- Geriatric Research Education and Clinical Center, VA Puget Sound Health Care System, 1660 S Columbian Way, Seattle, WA 98108, USA;
- Department of Medicine, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Stephen T. Ahlers
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical ResearchCommand, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA; (R.A.); (U.K.); (S.T.A.)
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8
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Halder SK, Sapkota A, Milner R. The importance of laminin at the blood-brain barrier. Neural Regen Res 2023; 18:2557-2563. [PMID: 37449589 DOI: 10.4103/1673-5374.373677] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
The blood-brain barrier is a unique property of central nervous system blood vessels that protects sensitive central nervous system cells from potentially harmful blood components. The mechanistic basis of this barrier is found at multiple levels, including the adherens and tight junction proteins that tightly bind adjacent endothelial cells and the influence of neighboring pericytes, microglia, and astrocyte endfeet. In addition, extracellular matrix components of the vascular basement membrane play a critical role in establishing and maintaining blood-brain barrier integrity, not only by providing an adhesive substrate for blood-brain barrier cells to adhere to, but also by providing guidance cues that strongly influence vascular cell behavior. The extracellular matrix protein laminin is one of the most abundant components of the basement membrane, and several lines of evidence suggest that it plays a key role in directing blood-brain barrier behavior. In this review, we describe the basic structure of laminin and its receptors, the expression patterns of these molecules in central nervous system blood vessels and how they are altered in disease states, and most importantly, how genetic deletion of different laminin isoforms or their receptors reveals the contribution of these molecules to blood-brain barrier function and integrity. Finally, we discuss some of the important unanswered questions in the field and provide a "to-do" list of some of the critical outstanding experiments.
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, San Diego, CA, USA
| | - Arjun Sapkota
- San Diego Biomedical Research Institute, San Diego, CA, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, San Diego, CA, USA
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9
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Quan H, Zhang R. Microglia dynamic response and phenotype heterogeneity in neural regeneration following hypoxic-ischemic brain injury. Front Immunol 2023; 14:1320271. [PMID: 38094292 PMCID: PMC10716326 DOI: 10.3389/fimmu.2023.1320271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/14/2023] [Indexed: 12/18/2023] Open
Abstract
Hypoxic-ischemic brain injury poses a significant threat to the neural niche within the central nervous system. In response to this pathological process, microglia, as innate immune cells in the central nervous system, undergo rapid morphological, molecular and functional changes. Here, we comprehensively review these dynamic changes in microglial response to hypoxic-ischemic brain injury under pathological conditions, including stroke, chronic intermittent hypoxia and neonatal hypoxic-ischemic brain injury. We focus on the regulation of signaling pathways under hypoxic-ischemic brain injury and further describe the process of microenvironment remodeling and neural tissue regeneration mediated by microglia after hypoxic-ischemic injury.
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Affiliation(s)
- Hongxin Quan
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
| | - Runrui Zhang
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan, China
- Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan, China
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10
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Lana D, Magni G, Landucci E, Wenk GL, Pellegrini-Giampietro DE, Giovannini MG. Phenomic Microglia Diversity as a Druggable Target in the Hippocampus in Neurodegenerative Diseases. Int J Mol Sci 2023; 24:13668. [PMID: 37761971 PMCID: PMC10531074 DOI: 10.3390/ijms241813668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
Phenomics, the complexity of microglia phenotypes and their related functions compels the continuous study of microglia in disease animal models to find druggable targets for neurodegenerative disorders. Activation of microglia was long considered detrimental for neuron survival, but more recently it has become apparent that the real scenario of microglia morphofunctional diversity is far more complex. In this review, we discuss the recent literature on the alterations in microglia phenomics in the hippocampus of animal models of normal brain aging, acute neuroinflammation, ischemia, and neurodegenerative disorders, such as AD. Microglia undergo phenomic changes consisting of transcriptional, functional, and morphological changes that transform them into cells with different properties and functions. The classical subdivision of microglia into M1 and M2, two different, all-or-nothing states is too simplistic, and does not correspond to the variety of phenotypes recently discovered in the brain. We will discuss the phenomic modifications of microglia focusing not only on the differences in microglia reactivity in the diverse models of neurodegenerative disorders, but also among different areas of the brain. For instance, in contiguous and highly interconnected regions of the rat hippocampus, microglia show a differential, finely regulated, and region-specific reactivity, demonstrating that microglia responses are not uniform, but vary significantly from area to area in response to insults. It is of great interest to verify whether the differences in microglia reactivity may explain the differential susceptibility of different brain areas to insults, and particularly the higher sensitivity of CA1 pyramidal neurons to inflammatory stimuli. Understanding the spatiotemporal heterogeneity of microglia phenomics in health and disease is of paramount importance to find new druggable targets for the development of novel microglia-targeted therapies in different CNS disorders. This will allow interventions in three different ways: (i) by suppressing the pro-inflammatory properties of microglia to limit the deleterious effect of their activation; (ii) by modulating microglia phenotypic change to favor anti-inflammatory properties; (iii) by influencing microglia priming early in the disease process.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Giada Magni
- Institute of Applied Physics “Nello Carrara”, National Research Council (IFAC-CNR), Via Madonna del Piano 10, 50019 Florence, Italy;
| | - Elisa Landucci
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Gary L. Wenk
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA;
| | - Domenico Edoardo Pellegrini-Giampietro
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy; (E.L.); (D.E.P.-G.); (M.G.G.)
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11
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Boghozian R, Sharma S, Narayana K, Cheema M, Brown CE. Sex and interferon gamma signaling regulate microglia migration in the adult mouse cortex in vivo. Proc Natl Acad Sci U S A 2023; 120:e2302892120. [PMID: 37428916 PMCID: PMC10629543 DOI: 10.1073/pnas.2302892120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 06/02/2023] [Indexed: 07/12/2023] Open
Abstract
Although microglia possess the unique ability to migrate, whether mobility is evident in all microglia, is sex dependent, and what molecular mechanisms drive this, is not well understood in the adult brain. Using longitudinal in vivo two-photon imaging of sparsely labeled microglia, we find a relatively small population of microglia (~5%) are mobile under normal conditions. Following injury (microbleed), the fraction of mobile microglia increased in a sex-dependent manner, with male microglia migrating significantly greater distances toward the microbleed relative to their female counterparts. To understand the signaling pathways involved, we interrogated the role of interferon gamma (IFNγ). Our data show that in male mice, stimulating microglia with IFNγ promotes migration whereas inhibiting IFNγ receptor 1 signaling inhibits them. By contrast, female microglia were generally unaffected by these manipulations. These findings highlight the diversity of microglia migratory responses to injury, its dependence on sex and the signaling mechanisms that modulate this behavior.
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Affiliation(s)
- Roobina Boghozian
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Kamal Narayana
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Manjinder Cheema
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Craig E. Brown
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, BCV6T 2A1, Canada
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12
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Halder SK, Milner R. Spinal Cord Blood Vessels in Aged Mice Show Greater Levels of Hypoxia-Induced Vascular Disruption and Microglial Activation. Int J Mol Sci 2023; 24:11235. [PMID: 37510999 PMCID: PMC10378993 DOI: 10.3390/ijms241411235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/06/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
In response to chronic mild hypoxia (CMH, 8% O2), spinal cord blood vessels launch a robust angiogenic response that is associated with transient disruption of the blood-spinal cord barrier (BSCB) which, in turn, triggers a microglial vasculo-protective response. Because hypoxia occurs in many age-related conditions, the goal of this study was to define how aging influences these responses by comparing events in young (8-10 weeks) and aged (20 months) mice. This revealed that aged mice had much greater (3-4-fold) levels of hypoxic-induced BSCB disruption than young mice and that, while the early stage of the angiogenic response in aged mice was no different to young mice, the maturation of newly formed vessels was significantly delayed. Interestingly, microglia in the spinal cords of aged mice were much more activated than young mice, even under normoxic conditions, and this was further enhanced by CMH, though, surprisingly, this resulted in reduced microglial clustering around leaky blood vessels and diminished vasculo-protection. Vascular disruption was associated with loss of myelin in spinal cord white matter (WM) in both young and aged mice. Furthermore, it was notable that the spinal cord of aged mice contained a lower density of Olig2+ oligodendroglial cells even under normoxic conditions and that CMH significantly reduced the density of Olig2+ cells in spinal cord WM of the aged, but not the young, mice. These results demonstrate that spinal cord blood vessels of aged mice are much more vulnerable to the damaging effects of hypoxia than young mice, in part due to the reduced vasculo-protection conferred by chronically activated microglial cells. These observations may have implications for the pathogenesis and/or treatment of spinal cord diseases such as amyotrophic lateral sclerosis (ALS) and suggest that an improvement in microglial function could offer therapeutic potential for treating these age-related conditions.
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Affiliation(s)
| | - Richard Milner
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA 92121, USA;
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13
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Novorolsky RJ, Kasheke GDS, Hakim A, Foldvari M, Dorighello GG, Sekler I, Vuligonda V, Sanders ME, Renden RB, Wilson JJ, Robertson GS. Preserving and enhancing mitochondrial function after stroke to protect and repair the neurovascular unit: novel opportunities for nanoparticle-based drug delivery. Front Cell Neurosci 2023; 17:1226630. [PMID: 37484823 PMCID: PMC10360135 DOI: 10.3389/fncel.2023.1226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/22/2023] [Indexed: 07/25/2023] Open
Abstract
The neurovascular unit (NVU) is composed of vascular cells, glia, and neurons that form the basic component of the blood brain barrier. This intricate structure rapidly adjusts cerebral blood flow to match the metabolic needs of brain activity. However, the NVU is exquisitely sensitive to damage and displays limited repair after a stroke. To effectively treat stroke, it is therefore considered crucial to both protect and repair the NVU. Mitochondrial calcium (Ca2+) uptake supports NVU function by buffering Ca2+ and stimulating energy production. However, excessive mitochondrial Ca2+ uptake causes toxic mitochondrial Ca2+ overloading that triggers numerous cell death pathways which destroy the NVU. Mitochondrial damage is one of the earliest pathological events in stroke. Drugs that preserve mitochondrial integrity and function should therefore confer profound NVU protection by blocking the initiation of numerous injury events. We have shown that mitochondrial Ca2+ uptake and efflux in the brain are mediated by the mitochondrial Ca2+ uniporter complex (MCUcx) and sodium/Ca2+/lithium exchanger (NCLX), respectively. Moreover, our recent pharmacological studies have demonstrated that MCUcx inhibition and NCLX activation suppress ischemic and excitotoxic neuronal cell death by blocking mitochondrial Ca2+ overloading. These findings suggest that combining MCUcx inhibition with NCLX activation should markedly protect the NVU. In terms of promoting NVU repair, nuclear hormone receptor activation is a promising approach. Retinoid X receptor (RXR) and thyroid hormone receptor (TR) agonists activate complementary transcriptional programs that stimulate mitochondrial biogenesis, suppress inflammation, and enhance the production of new vascular cells, glia, and neurons. RXR and TR agonism should thus further improve the clinical benefits of MCUcx inhibition and NCLX activation by increasing NVU repair. However, drugs that either inhibit the MCUcx, or stimulate the NCLX, or activate the RXR or TR, suffer from adverse effects caused by undesired actions on healthy tissues. To overcome this problem, we describe the use of nanoparticle drug formulations that preferentially target metabolically compromised and damaged NVUs after an ischemic or hemorrhagic stroke. These nanoparticle-based approaches have the potential to improve clinical safety and efficacy by maximizing drug delivery to diseased NVUs and minimizing drug exposure in healthy brain and peripheral tissues.
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Affiliation(s)
- Robyn J. Novorolsky
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Gracious D. S. Kasheke
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Antoine Hakim
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Marianna Foldvari
- School of Pharmacy, Faculty of Science, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel G. Dorighello
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Israel Sekler
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben Gurion University, Beersheva, Israel
| | | | | | - Robert B. Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Justin J. Wilson
- Department of Chemistry and Chemical Biology, College of Arts and Sciences, Cornell University, Ithaca, NY, United States
| | - George S. Robertson
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Brain Repair Centre, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
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14
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Halder SK, Delorme-Walker VD, Milner R. β1 integrin is essential for blood-brain barrier integrity under stable and vascular remodelling conditions; effects differ with age. Fluids Barriers CNS 2023; 20:52. [PMID: 37400852 DOI: 10.1186/s12987-023-00453-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/14/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Maintaining a tight blood-brain barrier (BBB) is an important prerequisite for the preservation of neurological health, though current evidence suggests it declines with age. While extracellular matrix-integrin interactions play critical roles in regulating the balance between vascular stability and remodeling, it remains to be established whether manipulation of integrin function weakens or strengthens vascular integrity. Indeed, recent reports have generated conflicting outcomes in this regard. METHODS Here, in young (8-10 weeks) and aged (20 months) mice, we examined the impact of intraperitoneal injection of a function-blocking β1 integrin antibody, both under normoxic conditions, when the BBB is stable, and during chronic mild hypoxic (CMH; 8% O2) conditions, when a vigorous vascular remodeling response is ongoing. Brain tissue was examined by immunofluorescence (IF) for markers of vascular remodeling and BBB disruption, and microglial activation and proliferation. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison post-hoc test. RESULTS In both young and aged mice, β1 integrin block greatly amplified hypoxia-induced vascular disruption, though it was much less under normoxic conditions. Interestingly, under both normoxic and hypoxic conditions, β1 integrin antibody-induced BBB disruption was greater in young mice. Enhanced BBB breakdown was associated with increased levels of the leaky BBB marker MECA-32 and with greater loss of endothelial tight junction proteins and the adherens protein VE-cadherin. Surprisingly, β1 integrin blockade did not reduce hypoxia-induced endothelial proliferation, nor did it prevent the hypoxia-associated increase in vascularity. Commensurate with the increased vascular disruption, β1 integrin blockade enhanced microglial activation both in young and aged brain, though the impact was much greater in young brain. In vitro studies revealed that β1 integrin blockade also reduced the integrity of a brain endothelial monolayer and triggered disruptions in tight junction proteins. CONCLUSIONS These data demonstrate that β1 integrin plays an essential role in maintaining BBB integrity, both under stable normoxic conditions and during hypoxia-induced vascular remodeling. As β1 integrin blockade had a greater disruptive effect in young brain, effectively shifting the BBB phenotype of young brain towards that of the aged, we speculate that enhancing β1 integrin function at the aged BBB may hold therapeutic potential by reverting the deteriorating BBB phenotype back towards that of the young.
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA
| | - Violaine D Delorme-Walker
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA.
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15
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Cao Y, Yue X, Jia M, Wang J. Neuroinflammation and anti-inflammatory therapy for ischemic stroke. Heliyon 2023; 9:e17986. [PMID: 37519706 PMCID: PMC10372247 DOI: 10.1016/j.heliyon.2023.e17986] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 04/25/2023] [Accepted: 07/04/2023] [Indexed: 08/01/2023] Open
Abstract
Stroke remains one of the most devastating and challenging neurological diseases worldwide. Inflammation, as well as oxidative stress is one of the main contributors to post-stroke injuries, and oxidative stress can further induce inflammation. Moreover, the inflammatory response is closely related to immune modulation in ischemic stroke progression. Hence, major ischemic stroke treatment strategies include targeting inflammatory responses, immune modulation (especially immune cells), and inflammatory response to suppress stroke progression. To date, several drugs have demonstrated clinical efficacy, such as Etanercept and Fingolimod. However, only edaravone dexborneol has successfully passed the phase III clinical trial and been approved by the National Medical Products Administration (NMPA) to treat ischemic stroke in China, which can restore redox balance and regulate inflammatory immune responses, thus providing neuroprotection in ischemic stroke. In this review, we will comprehensively summarize the current advances in the application of inflammatory biomarkers, neuroinflammation and neuro-immunotherapeutic scenarios for ischemic stroke, thus aiming to provide a theoretical basis and new prospects and frontiers for clinical applications.
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Affiliation(s)
- Yangyue Cao
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xuanye Yue
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Meng Jia
- National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jiawei Wang
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
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16
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Halder SK, Sapkota A, Milner R. Harnessing the vasculo-protective potential of microglia. Aging (Albany NY) 2023; 15:597-598. [PMID: 36734938 PMCID: PMC9970318 DOI: 10.18632/aging.204509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 01/24/2023] [Indexed: 02/04/2023]
Affiliation(s)
- Sebok K. Halder
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
| | - Arjun Sapkota
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
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17
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Gao L, Pan X, Zhang JH, Xia Y. Glial cells: an important switch for the vascular function of the central nervous system. Front Cell Neurosci 2023; 17:1166770. [PMID: 37206667 PMCID: PMC10188976 DOI: 10.3389/fncel.2023.1166770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023] Open
Abstract
In this review, we first describe the current understanding of glial-mediated vascular function affecting the role of the blood-brain barrier (BBB) in central nervous system (CNS) disorders. BBB, mainly composed of glial and endothelial cells (ECs), is the protective structure that orchestrates the transport of substances, including ions, molecules, and cells from brain vessels into or out of the CNS. Then, we display the multiple communication between glial and vascular function based on angiogenesis, vascular wrapping, and blood perfusion in the brain. Glial can support microvascular ECs to form a blood network connecting to neurons. Astrocytes, microglia, and oligodendrocytes are the common types of glial surrounding the brain vessel. Glial-vessel interaction is required for the permeability and integrity of BBB. Glial cells surrounding the cerebral blood vessels can transmit communication signals to ECs and regulate the activity of vascular endothelial growth factor (VEGF) or Wnt-dependent endothelial angiogenesis mechanism. In addition, these glial cells monitor the blood flow in the brain via Ca2+/K+-dependent pathways. Finally, we provide a potential research direction for the glial-vessel axis in CNS disorders. Microglial activation can trigger astrocyte activation, which suggests that microglia-astrocyte interaction may play a key role in monitoring cerebral blood flow. Thus, microglia-astrocyte interaction can be the key point of follow-up studies focusing on the microglia-blood mechanism. More investigations focus on the mechanism of how oligodendrocyte progenitor cells communicate and interact with ECs. The direct role of oligodendrocytes in modulating vascular function needs to be explored in the future.
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Affiliation(s)
- Ling Gao
- Department of Neurosurgery, Affiliated Haikou Hospital, Xiangya School of Medicine, Central South University, Haikou, China
- Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Xuezhen Pan
- Department of Neurosurgery, Affiliated Haikou Hospital, Xiangya School of Medicine, Central South University, Haikou, China
| | - John H. Zhang
- Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
- John H. Zhang,
| | - Ying Xia
- Department of Neurosurgery, Affiliated Haikou Hospital, Xiangya School of Medicine, Central South University, Haikou, China
- *Correspondence: Ying Xia,
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18
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Galea E, Graeber MB. Neuroinflammation: The Abused Concept. ASN Neuro 2023; 15:17590914231197523. [PMID: 37647500 PMCID: PMC10469255 DOI: 10.1177/17590914231197523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023] Open
Abstract
Scientific progress requires the relentless correction of errors and refinement of hypotheses. Clarity of terminology is essential for clarity of thought and proper experimental interrogation of nature. Therefore, the application of the same scientific term to different and even conflicting phenomena and concepts is not useful and must be corrected. Such abuse of terminology has happened and is still increasing in the case of "neuroinflammation," a term that until the 1990s meant classical inflammation affecting the central nervous system (CNS) and thereon was progressively used to mostly denote microglia activation. The resulting confusion is very wasteful and detrimental not only for scientists but also for patients, given the numerous failed clinical trials in acute and chronic CNS diseases over the last decade with "anti-inflammatory" drugs. Despite this failure, reassessments of the "neuroinflammation" concept are rare, especially considering the number of articles still using the term. This undesirable situation motivates this article. We review the origins and evolution of the term "neuroinflammation," discuss the unique tissue defense and repair strategies in the CNS, define CNS immunity, and emphasize the notion of gliopathies to help readdress, if not bury, the term "neuroinflammation" as it stands in the way of scientific progress.
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Affiliation(s)
- Elena Galea
- Departament de Bioquímica, Unitat de Bioquímica, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
- ICREA, Barcelona, Spain
| | - Manuel B. Graeber
- Faculty of Medicine and Health, Brain and Mind Centre, The University of Sydney, Camperdown, Australia
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19
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Knopp RC, Banks WA, Erickson MA. Physical associations of microglia and the vascular blood-brain barrier and their importance in development, health, and disease. Curr Opin Neurobiol 2022; 77:102648. [PMID: 36347075 DOI: 10.1016/j.conb.2022.102648] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022]
Abstract
Brain endothelial cells (BEC) of the vascular blood-brain barrier (BBB) interact with many different cell types in the brain, including microglia, the brain's resident immune cells. Physical associations of microglia with the BBB and the importance of these interactions in health and disease are an emerging area of study and likely involved in neuroimmune communication. In this mini-review, we consider how microglia and the BBB are intrinsically linked in the developing brain, discuss possible mechanisms that attract microglia to the vasculature in healthy physiological conditions, and examine the known microglial-vascular associated changes in systemic infection and various disease states. Our findings shed light on the complexities of microglial-vascular interactions and highlight the contributions of microglia to the functions of the neurovascular unit.
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Affiliation(s)
- Rachel C Knopp
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - William A Banks
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - Michelle A Erickson
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
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20
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Halder SK, Milner R. Exaggerated hypoxic vascular breakdown in aged brain due to reduced microglial vasculo-protection. Aging Cell 2022; 21:e13720. [PMID: 36130175 PMCID: PMC9649604 DOI: 10.1111/acel.13720] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/04/2022] [Accepted: 08/31/2022] [Indexed: 01/25/2023] Open
Abstract
In a recent study of young mice, we showed that chronic mild hypoxia (CMH, 8% O2 ) triggers transient blood-brain barrier (BBB) disruption, and that microglia play an important vasculo-protective function in maintaining BBB integrity. As hypoxia is a common component of many age-related diseases, here we extended these studies to aged mice and found that hypoxia-induced vascular leak was greatly amplified (5-fold to 10-fold) in aged mice, being particularly high in the olfactory bulb and midbrain. While aged mice showed no obvious difference in the early stages of hypoxic angiogenic remodeling, the compensatory increase in vascularity and vessel maturation was significantly delayed. Compared with young brain, microglia in the normoxic aged brain were markedly activated, and this was further increased under hypoxic conditions, but paradoxically, this correlated with reduced vasculo-protection. Microglial depletion studies showed that microglial still play an important vasculo-protective role in aged brain, but interestingly, partial attenuation of microglial activation with minocycline resulted in fewer vascular leaks and reduced loss of endothelial tight junction proteins. Taken together, these findings suggest that increased BBB disruption in hypoxic aged mice can be explained both by a delayed vascular remodeling response and reduced microglial vasculo-protection. Importantly, they show that overly activated microglia in the aged brain are less effective at maintaining vascular integrity, though this can be improved by reducing microglial activation with minocycline, suggesting therapeutic potential for enhancing BBB integrity in the hypoxia-predisposed elderly population.
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Affiliation(s)
- Sebok K. Halder
- San Diego Biomedical Research InstituteSan DiegoCaliforniaUSA
| | - Richard Milner
- San Diego Biomedical Research InstituteSan DiegoCaliforniaUSA
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21
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Basova LV, Bortell N, Conti B, Fox HS, Milner R, Marcondes MCG. Age-associated changes in microglia activation and Sirtuin-1- chromatin binding patterns. Aging (Albany NY) 2022; 14:8205-8220. [PMID: 36227148 PMCID: PMC9648798 DOI: 10.18632/aging.204329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/30/2022] [Indexed: 11/25/2022]
Abstract
The aging process is associated with changes in mechanisms maintaining physiology, influenced by genetics and lifestyle, and impacting late life quality and longevity. Brain health is critical in healthy aging. Sirtuin 1 (Sirt1), a histone deacetylase with silencing properties, is one of the molecular determinants experimentally linked to health and longevity. We compared brain pathogenesis and Sirt1-chromatin binding dynamics in brain pre-frontal cortex from 2 groups of elder rhesus macaques, divided by age of necropsy: shorter-lived animals (18-20 years old (yo)), equivalent to 60-70 human yo; and longer-lived animals (23-29 yo), corresponding to 80-100 human yo and modeling successful aging. These were compared with young adult brains (4-7 yo). Our findings indicated drastic differences in the microglia marker Iba1, along with factors influencing Sirt1 levels and activity, such as CD38 (an enzyme limiting NAD that controls Sirt1 activity) and mir142 (a microRNA targeting Sirt1 transcription) between the elder groups. Iba1 was lower in shorter-lived animals than in the other groups, while CD38 was higher in both aging groups compared to young. mir142 and Sirt1 levels were inversely correlated in longer-lived brains (>23yo), but not in shorter-lived brains (18-20 yo). We also found that Sirt1 binding showed signs of better efficiency in longer-lived animals compared to shorter-lived ones, in genes associated with nuclear activity and senescence. Overall, differences in neuroinflammation and Sirt1 interactions with chromatin distinguished shorter- and longer-lived animals, suggesting the importance of preserving microglia and Sirt1 functional efficiency for longevity.
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Affiliation(s)
- Liana V. Basova
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
| | | | - Bruno Conti
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
| | - Howard S. Fox
- University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, San Diego, CA 92121, USA
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22
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Berthiaume AA, Schmid F, Stamenkovic S, Coelho-Santos V, Nielson CD, Weber B, Majesky MW, Shih AY. Pericyte remodeling is deficient in the aged brain and contributes to impaired capillary flow and structure. Nat Commun 2022; 13:5912. [PMID: 36207315 PMCID: PMC9547063 DOI: 10.1038/s41467-022-33464-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/14/2022] [Indexed: 02/06/2023] Open
Abstract
Deterioration of brain capillary flow and architecture is a hallmark of aging and dementia. It remains unclear how loss of brain pericytes in these conditions contributes to capillary dysfunction. Here, we conduct cause-and-effect studies by optically ablating pericytes in adult and aged mice in vivo. Focal pericyte loss induces capillary dilation without blood-brain barrier disruption. These abnormal dilations are exacerbated in the aged brain, and result in increased flow heterogeneity in capillary networks. A subset of affected capillaries experience reduced perfusion due to flow steal. Some capillaries stall in flow and regress, leading to loss of capillary connectivity. Remodeling of neighboring pericytes restores endothelial coverage and vascular tone within days. Pericyte remodeling is slower in the aged brain, resulting in regions of persistent capillary dilation. These findings link pericyte loss to disruption of capillary flow and structure. They also identify pericyte remodeling as a therapeutic target to preserve capillary flow dynamics.
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Affiliation(s)
- Andrée-Anne Berthiaume
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Franca Schmid
- Institute of Fluid Dynamics, ETH Zurich, Sonneggstrasse 3, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
| | - Stefan Stamenkovic
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Vanessa Coelho-Santos
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Cara D Nielson
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
- Graduate Program in Neuroscience, University of Washington, Seattle, WA, USA
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Winterthurerstrasse 190, Zurich, Switzerland
| | - Mark W Majesky
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA.
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Department of Pediatrics, University of Washington, Seattle, WA, USA.
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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23
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Smith BC, Tinkey RA, Shaw BC, Williams JL. Targetability of the neurovascular unit in inflammatory diseases of the central nervous system. Immunol Rev 2022; 311:39-49. [PMID: 35909222 PMCID: PMC9489669 DOI: 10.1111/imr.13121] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The blood-brain barrier (BBB) is a selectively permeable barrier separating the periphery from the central nervous system (CNS). The BBB restricts the flow of most material into and out of the CNS, including many drugs that could be used as potent therapies. BBB permeability is modulated by several cells that are collectively called the neurovascular unit (NVU). The NVU consists of specialized CNS endothelial cells (ECs), pericytes, astrocytes, microglia, and neurons. CNS ECs maintain a complex "seal" via tight junctions, forming the BBB; breakdown of these tight junctions leads to BBB disruption. Pericytes control the vascular flow within capillaries and help maintain the basal lamina. Astrocytes control much of the flow of material that has moved beyond the CNS EC layer and can form a secondary barrier under inflammatory conditions. Microglia survey the border of the NVU for noxious material. Neuronal activity also plays a role in the maintenance of the BBB. Since astrocytes, pericytes, microglia, and neurons are all able to modulate the permeability of the BBB, understating the complex contributions of each member of the NVU will potentially uncover novel and effective methods for delivery of neurotherapies to the CNS.
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Affiliation(s)
- Brandon C. Smith
- Department of NeurosciencesLerner Research Institute, Cleveland ClinicClevelandOhioUSA,Department of Biological, Geological, and Environmental SciencesCleveland State UniversityClevelandOhioUSA
| | - Rachel A. Tinkey
- Department of NeurosciencesLerner Research Institute, Cleveland ClinicClevelandOhioUSA,School of Biomedical SciencesKent State UniversityKentOhioUSA
| | - Benjamin C. Shaw
- Department of NeurosciencesLerner Research Institute, Cleveland ClinicClevelandOhioUSA
| | - Jessica L. Williams
- Department of NeurosciencesLerner Research Institute, Cleveland ClinicClevelandOhioUSA,Brain Health Research Institute, Kent State UniversityKentOhioUSA
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24
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Microglia Contributes to BAF-312 Effects on Blood–Brain Barrier Stability. Biomolecules 2022; 12:biom12091174. [PMID: 36139013 PMCID: PMC9496388 DOI: 10.3390/biom12091174] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
Microglia, together with astrocytes and pericytes, cooperate to ensure blood–brain barrier (BBB) stability, modulating endothelial responses to inflammatory insults. Agonists of the sphingosine 1 phosphate (S1P) receptors, such as siponimod (BAF-312), are important pharmacological tools in multiple sclerosis and other inflammatory diseases. Modulation of S1P receptors may result in a reduced inflammatory response and increased BBB stability. An in vitro BBB model was reproduced using human-derived endothelial cells, astrocytes and microglia. Co-cultures were exposed to inflammatory cytokines (TNFα, 10 UI and IFNγ, 5 UI) in the presence of BAF-312 (100 nM), and the BBB properties and microglia role were evaluated. The drug facilitated microglial migration towards endothelial/astrocyte co-cultures, involving the activity of the metalloprotease 2 (MMP2). Microglia actively cooperated with astrocytes in the maintenance of endothelial barrier stability: in the triple co-culture, selective treatment of microglial cells with BAF-312 significantly prevented cytokines’ effects on the endothelial barrier. In conclusion, BAF-312, modulating S1P receptors in microglia, may contribute to the reinforcement of the endothelial barrier at the BBB, suggesting an additional effect of the drug in the treatment of multiple sclerosis.
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25
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Chen S, Li L, Peng C, Bian C, Ocak PE, Zhang JH, Yang Y, Zhou D, Chen G, Luo Y. Targeting Oxidative Stress and Inflammatory Response for Blood-Brain Barrier Protection in Intracerebral Hemorrhage. Antioxid Redox Signal 2022; 37:115-134. [PMID: 35383484 DOI: 10.1089/ars.2021.0072] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Significance: Blood-brain barrier (BBB) disruption is a major pathological change after intracerebral hemorrhage (ICH) and is both the cause and result of oxidative stress and of the immune response post-ICH. These processes contribute to ICH-induced brain injury. Recent Advances: After the breakdown of cerebral vessels, blood components, including erythrocytes and their metabolites, thrombin, and fibrinogen, can access the cerebral parenchyma through the compromised BBB, triggering oxidative stress and inflammatory cascades. These aggravate BBB disruption and contribute to further infiltration of blood components, resulting in a vicious cycle that exacerbates brain edema and neurological injury after ICH. Experimental and clinical studies have highlighted the role of BBB disruption in ICH-induced brain injury. Critical Issues: In this review, we focus on the strategies to protect the BBB in ICH. Specifically, we summarize the evidence and the underlying mechanisms, including the ICH-induced process of oxidative stress and inflammatory response, and we highlight the potential therapeutic targets to protect BBB integrity after ICH. Future Directions: Future studies should probe the mechanism of ferroptosis as well as oxidative stress-inflammation coupling in BBB disruption after ICH and investigate the effects of antioxidants and immunomodulatory agents in more ICH clinical trials. Antioxid. Redox Signal. 37, 115-134.
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Affiliation(s)
- Shengpan Chen
- Department of Neurosurgery, Guangdong Provincial People's Hospital, Guangdong Institute of Neuroscience, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Lingzhi Li
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Chao Peng
- Department of Neurosurgery, Guangdong Provincial People's Hospital, Guangdong Institute of Neuroscience, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Chunjing Bian
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Pinar Eser Ocak
- Department of Neurosurgery, Uludag University School of Medicine, Bursa, Turkey
| | - John H Zhang
- Department of Physiology and Pharmacology, School of Medicine, Loma Linda University, Loma Linda, California, USA
- Department of Neurosurgery, Loma Linda University, Loma Linda, California, USA
| | - Yong Yang
- Department of Neurosurgery, Guangdong Provincial People's Hospital, Guangdong Institute of Neuroscience, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Dong Zhou
- Department of Neurosurgery, Guangdong Provincial People's Hospital, Guangdong Institute of Neuroscience, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Guangzhong Chen
- Department of Neurosurgery, Guangdong Provincial People's Hospital, Guangdong Institute of Neuroscience, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yumin Luo
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
- Beijing Geriatric Medical Research Center and Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, China
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26
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Burtscher J, Niedermeier M, Hüfner K, van den Burg E, Kopp M, Stoop R, Burtscher M, Gatterer H, Millet GP. The interplay of hypoxic and mental stress: Implications for anxiety and depressive disorders. Neurosci Biobehav Rev 2022; 138:104718. [PMID: 35661753 DOI: 10.1016/j.neubiorev.2022.104718] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 12/14/2022]
Abstract
Adequate oxygen supply is essential for the human brain to meet its high energy demands. Therefore, elaborate molecular and systemic mechanism are in place to enable adaptation to low oxygen availability. Anxiety and depressive disorders are characterized by alterations in brain oxygen metabolism and of its components, such as mitochondria or hypoxia inducible factor (HIF)-pathways. Conversely, sensitivity and tolerance to hypoxia may depend on parameters of mental stress and the severity of anxiety and depressive disorders. Here we discuss relevant mechanisms of adaptations to hypoxia, as well as their involvement in mental stress and the etiopathogenesis of anxiety and depressive disorders. We suggest that mechanisms of adaptations to hypoxia (including metabolic responses, inflammation, and the activation of chemosensitive brain regions) modulate and are modulated by stress-related pathways and associated psychiatric diseases. While severe chronic hypoxia or dysfunctional hypoxia adaptations can contribute to the pathogenesis of anxiety and depressive disorders, harnessing controlled responses to hypoxia to increase cellular and psychological resilience emerges as a novel treatment strategy for these diseases.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Martin Niedermeier
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Clinic for Psychiatry II, Innsbruck Medical University, Innsbruck, Austria
| | - Erwin van den Burg
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Kopp
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Ron Stoop
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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27
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Halder SK, Sapkota A, Milner R. The impact of genetic manipulation of laminin and integrins at the blood-brain barrier. Fluids Barriers CNS 2022; 19:50. [PMID: 35690759 PMCID: PMC9188059 DOI: 10.1186/s12987-022-00346-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/18/2022] [Indexed: 12/26/2022] Open
Abstract
Blood vessels in the central nervous system (CNS) are unique in having high electrical resistance and low permeability, which creates a selective barrier protecting sensitive neural cells within the CNS from potentially harmful components in the blood. The molecular basis of this blood–brain barrier (BBB) is found at the level of endothelial adherens and tight junction protein complexes, extracellular matrix (ECM) components of the vascular basement membrane (BM), and the influence of adjacent pericytes and astrocyte endfeet. Current evidence supports the concept that instructive cues from the BBB ECM are not only important for the development and maturation of CNS blood vessels, but they are also essential for the maintenance of vascular stability and BBB integrity. In this review, we examine the contributions of one of the most abundant ECM proteins, laminin to BBB integrity, and summarize how genetic deletions of different laminin isoforms or their integrin receptors impact BBB development, maturation, and stability.
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA
| | - Arjun Sapkota
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, 3525 John Hopkins Court, Suite 200, San Diego, CA, 92121, USA.
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28
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Tsivelekas KK, Evangelopoulos DS, Pallis D, Benetos IS, Papadakis SA, Vlamis J, Pneumaticos SG. Angiogenesis in Spinal Cord Injury: Progress and Treatment. Cureus 2022; 14:e25475. [PMID: 35800787 PMCID: PMC9246426 DOI: 10.7759/cureus.25475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2022] [Indexed: 11/22/2022] Open
Abstract
Traumatic spinal cord injury (SCI) provokes the onset of an intricate pathological process. Initial primary injury ruptures local micro-neuro-vascularcomplex triggering the commencement of multi-factorial secondary sequences which exert significant influence on neurological deterioration progress. Stimulating by local ischemia, neovascularization pathways emerge to provide neuroprotection and improve functional recovery. Although angiogenetic processes are prompted, newly formed vascular system is frequently inadequate to distribute sufficient blood supply and improve axonal recovery. Several treatment interventions have been endeavored to achieve the optimal conditions in SCI microenvironment, enhancing angiogenesis and improve functional recovery. In this study we review the revascularization pathogenesis and importance within the secondary processes and condense the proangiogenic influence of several angiogenetic-targeted treatment interventions.
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29
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Advances in Visualizing Microglial Cells in Human Central Nervous System Tissue. Biomolecules 2022; 12:biom12050603. [PMID: 35625531 PMCID: PMC9138569 DOI: 10.3390/biom12050603] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 04/12/2022] [Accepted: 04/13/2022] [Indexed: 02/06/2023] Open
Abstract
Neuroinflammation has recently been identified as a fundamentally important pathological process in most, if not all, CNS diseases. The main contributor to neuroinflammation is the microglia, which constitute the innate immune response system. Accurate identification of microglia and their reactivity state is therefore essential to further our understanding of CNS pathophysiology. Many staining techniques have been used to visualise microglia in rodent and human tissue, and immunostaining is currently the most frequently used. Historically, identification of microglia was predominantly based on morphological structure, however, recently there has been a reliance on selective antigen expression, and microglia-specific markers have been identified providing increased certainty that the cells observed are in fact microglia, rather than the similar yet distinct macrophages. To date, the most microglia-specific markers are P2Y12 and TMEM119. However, other microglia-related markers can also be useful for demonstrating activation state, phagocytic state, and for neuroimaging purposes in longitudinal studies. Overall, it is important to be aware of the microglia-selectivity issues of the various stains and immunomarkers used by researchers to distinguish microglia in CNS tissue to avoid misinterpretation.
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30
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Marola OJ, Howell GR, Libby RT. Vascular derived endothelin receptor A controls endothelin-induced retinal ganglion cell death. Cell Death Dis 2022; 8:207. [PMID: 35429992 PMCID: PMC9013356 DOI: 10.1038/s41420-022-00985-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/13/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022]
Abstract
Endothelin (EDN, also known as ET) signaling has been suggested to be an important mediator of retinal ganglion cell (RGC) death in glaucoma. Antagonism of EDN receptors (EDNRA and EDNRB, also known as ET-A and ET-B) prevented RGC death in mouse models of chronic ocular hypertension, and intravitreal injection of EDN ligand was sufficient to drive RGC death. However, it remains unclear which cell types EDN ligands directly affect to elicit RGC death. Multiple cell types in the retina and optic nerve express EDNRA and EDNRB and thus could respond to EDN ligands in the context of glaucoma. Here, we systematically deleted Edn receptors from specific cell types to identify the critical EDN receptor mediating RGC death in vivo. Deletion of both Ednra and Ednrb from retinal neurons (including RGCs) and macroglia did not prevent RGC loss after exposure to EDN1 ligands, suggesting EDN1 ligands cause RGC death via an indirect mechanism involving a secondary cell type. Deletion of Ednra from the full body, and then specifically from vascular mural cells, prevented EDN1-induced vasoconstriction and RGC death. Together, these data suggest EDN ligands cause RGC death via a mechanism initiated by vascular mural cells. It is possible RGC death is a consequence of vascular mural cell-induced vasoconstriction and its pathological sequelae. These results highlight the potential importance of neurovascular dysfunction in glaucoma.
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31
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Császár E, Lénárt N, Cserép C, Környei Z, Fekete R, Pósfai B, Balázsfi D, Hangya B, Schwarcz AD, Szabadits E, Szöllősi D, Szigeti K, Máthé D, West BL, Sviatkó K, Brás AR, Mariani JC, Kliewer A, Lenkei Z, Hricisák L, Benyó Z, Baranyi M, Sperlágh B, Menyhárt Á, Farkas E, Dénes Á. Microglia modulate blood flow, neurovascular coupling, and hypoperfusion via purinergic actions. J Exp Med 2022; 219:213035. [PMID: 35201268 PMCID: PMC8932534 DOI: 10.1084/jem.20211071] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/28/2021] [Accepted: 01/03/2022] [Indexed: 12/13/2022] Open
Abstract
Microglia, the main immunocompetent cells of the brain, regulate neuronal function, but their contribution to cerebral blood flow (CBF) regulation has remained elusive. Here, we identify microglia as important modulators of CBF both under physiological conditions and during hypoperfusion. Microglia establish direct, dynamic purinergic contacts with cells in the neurovascular unit that shape CBF in both mice and humans. Surprisingly, the absence of microglia or blockade of microglial P2Y12 receptor (P2Y12R) substantially impairs neurovascular coupling in mice, which is reiterated by chemogenetically induced microglial dysfunction associated with impaired ATP sensitivity. Hypercapnia induces rapid microglial calcium changes, P2Y12R-mediated formation of perivascular phylopodia, and microglial adenosine production, while depletion of microglia reduces brain pH and impairs hypercapnia-induced vasodilation. Microglial actions modulate vascular cyclic GMP levels but are partially independent of nitric oxide. Finally, microglial dysfunction markedly impairs P2Y12R-mediated cerebrovascular adaptation to common carotid artery occlusion resulting in hypoperfusion. Thus, our data reveal a previously unrecognized role for microglia in CBF regulation, with broad implications for common neurological diseases.
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Affiliation(s)
- Eszter Császár
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Nikolett Lénárt
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Csaba Cserép
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Zsuzsanna Környei
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Rebeka Fekete
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Pósfai
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Diána Balázsfi
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Balázs Hangya
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Anett D Schwarcz
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Eszter Szabadits
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
| | - Dávid Szöllősi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Domokos Máthé
- Hungarian Centre of Excellence for Molecular Medicine, Szeged, Hungary
| | | | - Katalin Sviatkó
- Lendület Laboratory of Systems Neuroscience, Institute of Experimental Medicine, Budapest, Hungary
| | - Ana Rita Brás
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School of Neurosciences, Schools of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Jean-Charles Mariani
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - Andrea Kliewer
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - Zsolt Lenkei
- Institute of Psychiatry and Neurosciences of Paris, INSERM U1266, Université de Paris, Paris, France
| | - László Hricisák
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltán Benyó
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Mária Baranyi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Ákos Menyhárt
- Hungarian Centre of Excellence for Molecular Medicine, University of Szeged, Cerebral Blood Flow and Metabolism Research Group, Szeged, Hungary.,Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Hungarian Centre of Excellence for Molecular Medicine, University of Szeged, Cerebral Blood Flow and Metabolism Research Group, Szeged, Hungary.,Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám Dénes
- "Momentum" Laboratory of Neuroimmunology, Institute of Experimental Medicine, Budapest, Hungary
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32
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van Vliet EA, Marchi N. Neurovascular unit dysfunction as a mechanism of seizures and epilepsy during aging. Epilepsia 2022; 63:1297-1313. [PMID: 35218208 PMCID: PMC9321014 DOI: 10.1111/epi.17210] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/23/2022] [Accepted: 02/23/2022] [Indexed: 11/30/2022]
Abstract
The term neurovascular unit (NVU) describes the structural and functional liaison between specialized brain endothelium, glial and mural cells, and neurons. Within the NVU, the blood‐brain barrier (BBB) is the microvascular structure regulating neuronal physiology and immune cross‐talk, and its properties adapt to brain aging. Here, we analyze a research framework where NVU dysfunction, caused by acute insults or disease progression in the aging brain, represents a converging mechanism underlying late‐onset seizures or epilepsy and neurological or neurodegenerative sequelae. Furthermore, seizure activity may accelerate brain aging by sustaining regional NVU dysfunction, and a cerebrovascular pathology may link seizures to comorbidities. Next, we focus on NVU diagnostic approaches that could be tailored to seizure conditions in the elderly. We also examine the impending disease‐modifying strategies based on the restoration of the NVU and, more in general, the homeostatic control of anti‐ and pro‐inflammatory players. We conclude with an outlook on current pre‐clinical knowledge gaps and clinical challenges pertinent to seizure onset and conditions in an aging population.
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Affiliation(s)
- Erwin A van Vliet
- Amsterdam UMC, University of Amsterdam, dept. of (Neuro)pathology, Amsterdam, the Netherlands.,University of Amsterdam, Swammerdam Institute for Life Sciences, Center for Neuroscience, Amsterdam, the Netherlands
| | - Nicola Marchi
- Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
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33
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McConnell HL, Mishra A. Cells of the Blood-Brain Barrier: An Overview of the Neurovascular Unit in Health and Disease. Methods Mol Biol 2022; 2492:3-24. [PMID: 35733036 PMCID: PMC9987262 DOI: 10.1007/978-1-0716-2289-6_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
The brain is endowed with highly specialized vasculature that is both structurally and functionally unique compared to vasculature supplying peripheral organs. The blood-brain barrier (BBB) is formed by endothelial cells of the cerebral vasculature and prevents extravasation of blood products into the brain to protect neural tissue and maintain a homeostatic environment. The BBB functions as part of the neurovascular unit (NVU), which is composed of neurons, astrocytes, and microglia in addition to the specialized endothelial cells, mural cells, and the basement membrane. Through coordinated intercellular signaling, these cells function as a dynamic unit to tightly regulate brain blood flow, vascular function, neuroimmune responses, and waste clearance. In this chapter, we review the functions of individual NVU components, describe neurovascular coupling as a classic example of NVU function, and discuss archetypal NVU pathophysiology during disease.
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Affiliation(s)
- Heather L McConnell
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA
- Office of Academic Development, Houston Methodist Research Institute, Houston, TX, USA
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, USA.
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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34
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Guo L, Zhu L. Multiple Roles of Peripheral Immune System in Modulating Ischemia/Hypoxia-Induced Neuroinflammation. Front Mol Biosci 2021; 8:752465. [PMID: 34881289 PMCID: PMC8645603 DOI: 10.3389/fmolb.2021.752465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/05/2021] [Indexed: 12/20/2022] Open
Abstract
Given combined efforts of neuroscience and immunology, increasing evidence has revealed the critical roles of the immune system in regulating homeostasis and disorders of the central nervous system (CNS). Microglia have long been considered as the only immune cell type in parenchyma, while at the interface between CNS and the peripheral (meninges, choroid plexus, and perivascular space), embryonically originated border-associated macrophages (BAMs) and multiple surveilling leukocytes capable of migrating into and out of the brain have been identified to function in the healthy brain. Hypoxia-induced neuroinflammation is the key pathological procedure that can be detected in healthy people at high altitude or in various neurodegenerative diseases, during which a very thin line between a beneficial response of the peripheral immune system in maintaining brain homeostasis and a pathological role in exacerbating neuroinflammation has been revealed. Here, we are going to focus on the role of the peripheral immune system and its crosstalk with CNS in the healthy brain and especially in hypobaric or ischemic hypoxia-associated neuroinflammation.
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Affiliation(s)
- Liang Guo
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Lingling Zhu
- Beijing Institute of Basic Medical Sciences, Beijing, China.,University of Nanhua, Hengyang, China.,Anhui Medical University, Hefei, China
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35
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Zhao M, Jiang XF, Zhang HQ, Sun JH, Pei H, Ma LN, Cao Y, Li H. Interactions between glial cells and the blood-brain barrier and their role in Alzheimer's disease. Ageing Res Rev 2021; 72:101483. [PMID: 34610479 DOI: 10.1016/j.arr.2021.101483] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/14/2021] [Accepted: 09/30/2021] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD), which is an irreversible neurodegenerative disorder characterized by senile plaques and neurofibrillary tangles, is the most common form of dementia worldwide. However, currently, there are no satisfying curative therapies for AD. The blood-brain barrier (BBB) acts as a selective physical barrier and plays protective roles in maintaining brain homeostasis. BBB dysfunction as an upstream or downstream event promotes the onset and progression of AD. Moreover, the pathogenesis of AD caused by BBB injury hasn't been well elucidated. Glial cells, BBB compartments and neurons form a minimal functional unit called the neurovascular unit (NVU). Emerging evidence suggests that glial cells are regulators in maintaining the BBB integrity and neuronal function. Illustrating the regulatory mechanism of glial cells in the BBB assists us in drawing a glial-vascular coupling diagram of AD, which may offer new insight into the pathogenesis of AD and early intervention strategies for AD. This review aims to summarize our current knowledge of glial-BBB interactions and their pathological implications in AD and to provide new therapeutic potentials for future investigations.
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36
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Halder SK, Milner R. The impact of chronic mild hypoxia on cerebrovascular remodelling; uncoupling of angiogenesis and vascular breakdown. Fluids Barriers CNS 2021; 18:50. [PMID: 34789271 PMCID: PMC8597176 DOI: 10.1186/s12987-021-00284-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chronic mild hypoxia (CMH, 8% O2) stimulates robust vascular remodelling in the brain, but it also triggers transient vascular disruption. This raises the fundamental question: is the vascular leak an unwanted side-effect of angiogenic remodelling or is it a pathological response, unrelated to endothelial proliferation, in which declining oxygen levels trigger endothelial dysfunction? METHODS To answer this question, mice were exposed to CMH (8% O2) for periods up to 14 days, after which, brain tissue was examined by immunofluorescence (IF) to determine which type of blood vessel (arteriole, capillary or venule) was most commonly associated with endothelial proliferation and vascular leak and how this correlated with tight junction protein expression. Vascular perfusion was examined using DiI. Data were analysed using one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison post-hoc test. RESULTS The following was observed: (1) most endothelial proliferation and extravascular fibrinogen leak occurred in capillaries and to a lesser degree in venules, (2) much to our surprise, endothelial proliferation and extravascular fibrinogen leak never colocalized, (3) interestingly however, endothelial proliferation was strongly associated with an intravascular fibrinogen staining pattern not seen in stable blood vessels, (4) DiI perfusion studies revealed that angiogenic vessels were adequately perfused, suggesting that fibrinogen retention in angiogenic vessels is not due to temporary closure of the vessel, but more likely because fibrinogen is retained within the vessel wall, (5) bromodeoxyuridine (BrdU) labelling as a means to more permanently label proliferating endothelial cells, confirmed lack of any connection between endothelial proliferation and extravascular fibrinogen leak, while (6) in contrast, proliferating microglia were detected within extravascular leaks. CONCLUSIONS Taken together, our findings support the concept that in the short-term, hypoxia-induced endothelial proliferation triggers transient fibrinogen deposition within the walls of angiogenic blood vessels, but no overt vascular leak occurs in these vessels. Importantly, endothelial proliferation and extravascular fibrinogen leaks never co-localize, demonstrating that extravascular leak is not an unwanted side-effect of angiogenic endothelial proliferation, but rather a dysfunctional vascular response to hypoxia that occurs in a distinct group of non-angiogenic blood vessels.
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Affiliation(s)
- Sebok K Halder
- San Diego Biomedical Research Institute, 10865 Road to the Cure, Suite 100, San Diego, CA, 92121, USA
| | - Richard Milner
- San Diego Biomedical Research Institute, 10865 Road to the Cure, Suite 100, San Diego, CA, 92121, USA.
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Lu D, Ma R, Xie Q, Xu Z, Yuan J, Ren M, Li J, Li Y, Wang J. Application and advantages of zebrafish model in the study of neurovascular unit. Eur J Pharmacol 2021; 910:174483. [PMID: 34481878 DOI: 10.1016/j.ejphar.2021.174483] [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: 07/14/2021] [Revised: 08/25/2021] [Accepted: 09/01/2021] [Indexed: 11/15/2022]
Abstract
The concept of "Neurovascular Unit" (NVU) was put forward, so that the research goal of Central Nervous System (CNS) diseases gradually transitioned from a single neuron to the structural and functional integrity of the NVU. Zebrafish has the advantages of high homology with human genes, strong reproductive capacity and visualization of neural circuits, so it has become an emerging model organism for NVU research and has been applied to a variety of CNS diseases. Based on CNKI (https://www.cnki.net/) and PubMed (https://pubmed.ncbi.nlm.nih.gov/about/) databases, the author of this article sorted out the relevant literature, analyzed the construction of a zebrafish model of various CNS diseases,and the use of diagrams showed the application of zebrafish in the NVU, revealed its relationship, which would provide new methods and references for the treatment and research of CNS diseases.
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Affiliation(s)
- Danni Lu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Rong Ma
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Qian Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Zhuo Xu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Jianmei Yuan
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Mihong Ren
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Jinxiu Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Yong Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China
| | - Jian Wang
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu, 611137, China; School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, China.
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38
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Gama Sosa MA, De Gasperi R, Pryor D, Perez Garcia GS, Perez GM, Abutarboush R, Kawoos U, Hogg S, Ache B, Janssen WG, Sowa A, Tetreault T, Cook DG, Tappan SJ, Gandy S, Hof PR, Ahlers ST, Elder GA. Low-level blast exposure induces chronic vascular remodeling, perivascular astrocytic degeneration and vascular-associated neuroinflammation. Acta Neuropathol Commun 2021; 9:167. [PMID: 34654480 PMCID: PMC8518227 DOI: 10.1186/s40478-021-01269-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/29/2021] [Indexed: 02/08/2023] Open
Abstract
Cerebral vascular injury as a consequence of blast-induced traumatic brain injury is primarily the result of blast wave-induced mechanical disruptions within the neurovascular unit. In rodent models of blast-induced traumatic brain injury, chronic vascular degenerative processes are associated with the development of an age-dependent post-traumatic stress disorder-like phenotype. To investigate the evolution of blast-induced chronic vascular degenerative changes, Long-Evans rats were blast-exposed (3 × 74.5 kPa) and their brains analyzed at different times post-exposure by X-ray microcomputed tomography, immunohistochemistry and electron microscopy. On microcomputed tomography scans, regional cerebral vascular attenuation or occlusion was observed as early as 48 h post-blast, and cerebral vascular disorganization was visible at 6 weeks and more accentuated at 13 months post-blast. Progression of the late-onset pathology was characterized by detachment of the endothelial and smooth muscle cellular elements from the neuropil due to degeneration and loss of arteriolar perivascular astrocytes. Development of this pathology was associated with vascular remodeling and neuroinflammation as increased levels of matrix metalloproteinases (MMP-2 and MMP-9), collagen type IV loss, and microglial activation were observed in the affected vasculature. Blast-induced chronic alterations within the neurovascular unit should affect cerebral blood circulation, glymphatic flow and intramural periarterial drainage, all of which may contribute to development of the blast-induced behavioral phenotype. Our results also identify astrocytic degeneration as a potential target for the development of therapies to treat blast-induced brain injury.
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Affiliation(s)
- Miguel A Gama Sosa
- General Medical Research Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
| | - Rita De Gasperi
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
| | - Dylan Pryor
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
| | - Georgina S Perez Garcia
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
| | - Gissel M Perez
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
| | - Rania Abutarboush
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc, Bethesda, MD, USA
| | - Usmah Kawoos
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine Inc, Bethesda, MD, USA
| | - Seth Hogg
- Micro Photonics, Inc, 1550 Pond Road, Suite 110, Allentown, PA, 18104, USA
| | - Benjamin Ache
- Micro Photonics, Inc, 1550 Pond Road, Suite 110, Allentown, PA, 18104, USA
| | - William G Janssen
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Allison Sowa
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | | | - David G Cook
- Geriatric Research Education and Clinical Center, VA Puget Sound Health Care System, 1660 S Columbian Way, Seattle, WA, 98108, USA
- Department of Medicine, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Susan J Tappan
- MBF Bioscience LLC, 185 Allen Brook Lane, Williston, VT, 05495, USA
| | - Sam Gandy
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
- Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- NFL Neurological Care Center, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Patrick R Hof
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Stephen T Ahlers
- Department of Neurotrauma, Operational and Undersea Medicine Directorate, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
| | - Gregory A Elder
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY, 10029, USA
- Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY, 10468, USA
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Lecordier S, Manrique-Castano D, El Moghrabi Y, ElAli A. Neurovascular Alterations in Vascular Dementia: Emphasis on Risk Factors. Front Aging Neurosci 2021; 13:727590. [PMID: 34566627 PMCID: PMC8461067 DOI: 10.3389/fnagi.2021.727590] [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: 06/19/2021] [Accepted: 08/05/2021] [Indexed: 12/25/2022] Open
Abstract
Vascular dementia (VaD) constitutes the second most prevalent cause of dementia in the world after Alzheimer’s disease (AD). VaD regroups heterogeneous neurological conditions in which the decline of cognitive functions, including executive functions, is associated with structural and functional alterations in the cerebral vasculature. Among these cerebrovascular disorders, major stroke, and cerebral small vessel disease (cSVD) constitute the major risk factors for VaD. These conditions alter neurovascular functions leading to blood-brain barrier (BBB) deregulation, neurovascular coupling dysfunction, and inflammation. Accumulation of neurovascular impairments over time underlies the cognitive function decline associated with VaD. Furthermore, several vascular risk factors, such as hypertension, obesity, and diabetes have been shown to exacerbate neurovascular impairments and thus increase VaD prevalence. Importantly, air pollution constitutes an underestimated risk factor that triggers vascular dysfunction via inflammation and oxidative stress. The review summarizes the current knowledge related to the pathological mechanisms linking neurovascular impairments associated with stroke, cSVD, and vascular risk factors with a particular emphasis on air pollution, to VaD etiology and progression. Furthermore, the review discusses the major challenges to fully elucidate the pathobiology of VaD, as well as research directions to outline new therapeutic interventions.
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Affiliation(s)
- Sarah Lecordier
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Daniel Manrique-Castano
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Yara El Moghrabi
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Ayman ElAli
- Neuroscience Axis, Research Center of CHU de Québec-Université Laval, Québec City, QC, Canada.,Department of Psychiatry and Neuroscience, Faculty of Medicine, Université Laval, Québec City, QC, Canada
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40
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St-Pierre MK, Šimončičová E, Bögi E, Tremblay MÈ. Shedding Light on the Dark Side of the Microglia. ASN Neuro 2021; 12:1759091420925335. [PMID: 32443939 PMCID: PMC7249604 DOI: 10.1177/1759091420925335] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Microglia, the resident immune cells of the central nervous system, are not a
homogeneous population; their morphology, molecular profile, and even their
ultrastructure greatly vary from one cell to another. Recent advances in the
field of neuroimmunology have helped to demystify the enigma that currently
surrounds microglial heterogeneity. Indeed, numerous microglial subtypes have
been discovered such as the disease-associated microglia, neurodegenerative
phenotype, and Cd11c-positive developmental population. Another subtype is the
dark microglia (DM), a population defined by its ultrastructural changes
associated with cellular stress. Since their first characterization using
transmission electron microscopy, they have been identified in numerous disease
conditions, from mouse models of Alzheimer’s disease, schizophrenia, fractalkine
signaling deficiency to chronic stress, just to name a few. A recent study also
identified the presence of cells with a similar ultrastructure to the DM in
postmortem brain samples from schizophrenic patients,
underlining the importance of understanding the function of these cells. In this
minireview, we aim to summarize the current knowledge on the DM, from their
initial ultrastructural characterization to their documentation in various
pathological contexts across multiple species. We will also highlight the
current limitations surrounding the study of these cells and the future that
awaits the DM.
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Affiliation(s)
| | - Eva Šimončičová
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval.,Department of Pharmacology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic.,Institute of Experimental Pharmacology and Toxicology, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Eszter Bögi
- Department of Pharmacology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval
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41
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The Role of Microglia in Modulating Neuroinflammation after Spinal Cord Injury. Int J Mol Sci 2021; 22:ijms22189706. [PMID: 34575871 PMCID: PMC8470129 DOI: 10.3390/ijms22189706] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/27/2021] [Accepted: 09/03/2021] [Indexed: 01/10/2023] Open
Abstract
The pathobiology of traumatic and nontraumatic spinal cord injury (SCI), including degenerative myelopathy, is influenced by neuroinflammation. The neuroinflammatory response is initiated by a multitude of injury signals emanating from necrotic and apoptotic cells at the lesion site, recruiting local and infiltrating immune cells that modulate inflammatory cascades to aid in the protection of the lesion site and encourage regenerative processes. While peripheral immune cells are involved, microglia, the resident immune cells of the central nervous system (CNS), are known to play a central role in modulating this response. Microglia are armed with numerous cell surface receptors that interact with neurons, astrocytes, infiltrating monocytes, and endothelial cells to facilitate a dynamic, multi-faceted injury response. While their origin and essential nature are understood, their mechanisms of action and spatial and temporal profiles warrant extensive additional research. In this review, we describe the role of microglia and the cellular network in SCI, discuss tools for their investigation, outline their spatiotemporal profile, and propose translationally-relevant therapeutic targets to modulate neuroinflammation in the setting of SCI.
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42
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Hanslik KL, Marino KM, Ulland TK. Modulation of Glial Function in Health, Aging, and Neurodegenerative Disease. Front Cell Neurosci 2021; 15:718324. [PMID: 34531726 PMCID: PMC8439422 DOI: 10.3389/fncel.2021.718324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/27/2021] [Indexed: 01/15/2023] Open
Abstract
In the central nervous system (CNS), glial cells, such as microglia and astrocytes, are normally associated with support roles including contributions to energy metabolism, synaptic plasticity, and ion homeostasis. In addition to providing support for neurons, microglia and astrocytes function as the resident immune cells in the brain. The glial function is impacted by multiple aspects including aging and local CNS changes caused by neurodegeneration. During aging, microglia and astrocytes display alterations in their homeostatic functions. For example, aged microglia and astrocytes exhibit impairments in the lysosome and mitochondrial function as well as in their regulation of synaptic plasticity. Recent evidence suggests that glia can also alter the pathology associated with many neurodegenerative disorders including Alzheimer's disease (AD) and Parkinson's disease (PD). Shifts in the microbiome can impact glial function as well. Disruptions in the microbiome can lead to aberrant microglial and astrocytic reactivity, which can contribute to an exacerbation of disease and neuronal dysfunction. In this review, we will discuss the normal physiological functions of microglia and astrocytes, summarize novel findings highlighting the role of glia in aging and neurodegenerative diseases, and examine the contribution of microglia and astrocytes to disease progression.
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Affiliation(s)
- Kendra L. Hanslik
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
| | - Kaitlyn M. Marino
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
| | - Tyler K. Ulland
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, United States
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43
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Microglia as the Critical Regulators of Neuroprotection and Functional Recovery in Cerebral Ischemia. Cell Mol Neurobiol 2021; 42:2505-2525. [PMID: 34460037 DOI: 10.1007/s10571-021-01145-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022]
Abstract
Microglial activation is considered as the critical pathogenic event in diverse central nervous system disorders including cerebral ischemia. Proinflammatory responses of activated microglia have been well reported in the ischemic brain and neuroinflammatory responses of activated microglia have been believed to be the potential therapeutic strategy. However, despite having proinflammatory roles, microglia can have significant anti-inflammatory roles and they are associated with the production of growth factors which are responsible for neuroprotection and recovery after ischemic injury. Microglia can directly promote neuroprotection by preventing ischemic infarct expansion and promoting functional outcomes. Indirectly, microglia are involved in promoting anti-inflammatory responses, neurogenesis, and angiogenesis in the ischemic brain which are crucial pathophysiological events for ischemic recovery. In fact, anti-inflammatory cytokines and growth factors produced by microglia can promote neuroprotection and attenuate neurobehavioral deficits. In addition, microglia regulate phagocytosis, axonal regeneration, blood-brain barrier protection, white matter integrity, and synaptic remodeling, which are essential for ischemic recovery. Microglia can also regulate crosstalk with neurons and other cell types to promote neuroprotection and ischemic recovery. This review mainly focuses on the roles of microglia in neuroprotection and recovery following ischemic injury. Furthermore, this review also sheds the light on the therapeutic potential of microglia in stroke patients.
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Kim W, Kwon HJ, Jung HY, Hahn KR, Moon SM, Yoon YS, Hwang IK, Choi SY, Kim DW. Tat-p27 Ameliorates Neuronal Damage Reducing α-Synuclein and Inflammatory Responses in Motor Neurons After Spinal Cord Ischemia. Neurochem Res 2021; 46:3123-3134. [PMID: 34403064 DOI: 10.1007/s11064-021-03392-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 11/25/2022]
Abstract
p27Kip1 (p27) regulates the cell cycle by inhibiting G1 progression in cells. Several studies have shown conflicting results on the effects of p27 against cell death in various insults. In the present study, we examined the neuroprotective effects of p27 against H2O2-induced oxidative stress in NSC34 cells and against spinal cord ischemia-induced neuronal damage in rabbits. To promote delivery into NSC34 cells and motor neurons in the spinal cord, Tat-p27 fusion protein and its control protein (Control-p27) were synthesized with or without Tat peptide, respectively. Tat-p27, but not Control-27, was efficiently introduced into NSC34 cells in a concentration- and time-dependent manner, and the protein was detected in the cytoplasm. Tat-p27 showed neuroprotective effects against oxidative stress induced by H2O2 treatment and reduced the formation of reactive oxygen species, DNA fragmentation, and lipid peroxidation in NSC34 cells. Tat-p27, but not Control-p27, ameliorated ischemia-induced neurological deficits and cell damage in the rabbit spinal cord. In addition, Tat-p27 treatment reduced the expression of α-synuclein, activation of microglia, and release of pro-inflammatory cytokines such as interleukin-1β and tumor necrosis factor-α in the spinal cord. Taken together, these results suggest that Tat-p27 inhibits neuronal damage by decreasing oxidative stress, α-synuclein expression, and inflammatory responses after ischemia.
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Affiliation(s)
- Woosuk Kim
- Department of Biomedical Sciences, Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon, 24252, South Korea
- Department of Anatomy, College of Veterinary Medicine, and Veterinary Science Research Institute, Konkuk University, Seoul, 05030, South Korea
| | - Hyun Jung Kwon
- Department of Biomedical Sciences, Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon, 24252, South Korea
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, 25457, South Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
- Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon, 34134, South Korea
| | - Kyu Ri Hahn
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Seung Myung Moon
- Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong, 18450, South Korea
- Research Institute for Complementary & Alternative Medicine, Hallym University, Chuncheon, 24253, South Korea
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
| | - Soo Young Choi
- Department of Biomedical Sciences, Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon, 24252, South Korea.
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung, 25457, South Korea.
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45
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Mehina EMF, Taylor S, Boghozian R, White E, Choi SE, Cheema MS, Korbelin J, Brown CE. Invasion of phagocytic Galectin 3 expressing macrophages in the diabetic brain disrupts vascular repair. SCIENCE ADVANCES 2021; 7:7/34/eabg2712. [PMID: 34407943 PMCID: PMC8373127 DOI: 10.1126/sciadv.abg2712] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
The cellular events that dictate the repair of damaged vessels in the brain, especially in those with vascular risk factors such as diabetes, is poorly understood. Here, we dissected the role of resident microglia and infiltrative macrophages in determining the repair of ruptured cerebral microvessels. Using in vivo time-lapse imaging, gene expression analysis, and immunohistochemistry, we identified a unique population of phagocytic Galectin 3 (Gal3) expressing macrophages, distinct from resident microglia, which infiltrated and aggregated at the site of injury in diabetic mice and were associated with the elimination of microvessels. Depletion of these infiltrative macrophages in diabetic mice attenuated phagocytic activity and prevented the loss of blood vessels after injury. These findings highlight a previously unknown role for infiltrative Gal3 expressing macrophages in promoting vessel elimination after brain injury and provide impetus for future studies to determine whether depleting these cells can facilitate vascular repair in at risk populations.
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Affiliation(s)
- Eslam M F Mehina
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Stephanie Taylor
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Roobina Boghozian
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Emily White
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Sun Eui Choi
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Manjinder S Cheema
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Jakob Korbelin
- Department of Oncology, Hematology and Bone Marrow Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Craig E Brown
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
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46
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Stackhouse TL, Mishra A. Neurovascular Coupling in Development and Disease: Focus on Astrocytes. Front Cell Dev Biol 2021; 9:702832. [PMID: 34327206 PMCID: PMC8313501 DOI: 10.3389/fcell.2021.702832] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/09/2021] [Indexed: 12/14/2022] Open
Abstract
Neurovascular coupling is a crucial mechanism that matches the high energy demand of the brain with a supply of energy substrates from the blood. Signaling within the neurovascular unit is responsible for activity-dependent changes in cerebral blood flow. The strength and reliability of neurovascular coupling form the basis of non-invasive human neuroimaging techniques, including blood oxygen level dependent (BOLD) functional magnetic resonance imaging. Interestingly, BOLD signals are negative in infants, indicating a mismatch between metabolism and blood flow upon neural activation; this response is the opposite of that observed in healthy adults where activity evokes a large oversupply of blood flow. Negative neurovascular coupling has also been observed in rodents at early postnatal stages, further implying that this is a process that matures during development. This rationale is consistent with the morphological maturation of the neurovascular unit, which occurs over a similar time frame. While neurons differentiate before birth, astrocytes differentiate postnatally in rodents and the maturation of their complex morphology during the first few weeks of life links them with synapses and the vasculature. The vascular network is also incomplete in neonates and matures in parallel with astrocytes. Here, we review the timeline of the structural maturation of the neurovascular unit with special emphasis on astrocytes and the vascular tree and what it implies for functional maturation of neurovascular coupling. We also discuss similarities between immature astrocytes during development and reactive astrocytes in disease, which are relevant to neurovascular coupling. Finally, we close by pointing out current gaps in knowledge that must be addressed to fully elucidate the mechanisms underlying neurovascular coupling maturation, with the expectation that this may also clarify astrocyte-dependent mechanisms of cerebrovascular impairment in neurodegenerative conditions in which reduced or negative neurovascular coupling is noted, such as stroke and Alzheimer’s disease.
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Affiliation(s)
- Teresa L Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States.,Knight Cardiovascular Institute, Oregon Health & Sciences University, Portland, OR, United States
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47
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Liu J, Gu Y, Guo M, Ji X. Neuroprotective effects and mechanisms of ischemic/hypoxic preconditioning on neurological diseases. CNS Neurosci Ther 2021; 27:869-882. [PMID: 34237192 PMCID: PMC8265941 DOI: 10.1111/cns.13642] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/20/2022] Open
Abstract
As the organ with the highest demand for oxygen, the brain has a poor tolerance to ischemia and hypoxia. Despite severe ischemia/hypoxia induces the occurrence and development of various central nervous system (CNS) diseases, sublethal insult may induce strong protection against subsequent fatal injuries by improving tolerance. Searching for potential measures to improve brain ischemic/hypoxic is of great significance for treatment of ischemia/hypoxia related CNS diseases. Ischemic/hypoxic preconditioning (I/HPC) refers to the approach to give the body a short period of mild ischemic/hypoxic stimulus which can significantly improve the body's tolerance to subsequent more severe ischemia/hypoxia event. It has been extensively studied and been considered as an effective therapeutic strategy in CNS diseases. Its protective mechanisms involved multiple processes, such as activation of hypoxia signaling pathways, anti-inflammation, antioxidant stress, and autophagy induction, etc. As a strategy to induce endogenous neuroprotection, I/HPC has attracted extensive attention and become one of the research frontiers and hotspots in the field of neurotherapy. In this review, we discuss the basic and clinical research progress of I/HPC on CNS diseases, and summarize its mechanisms. Furthermore, we highlight the limitations and challenges of their translation from basic research to clinical application.
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Affiliation(s)
- Jia Liu
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Yakun Gu
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Mengyuan Guo
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China
| | - Xunming Ji
- Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Capital Medical University, Beijing, China.,Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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48
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Barca C, Kiliaan AJ, Foray C, Wachsmuth L, Hermann S, Faber C, Schaefers M, Wiesmann M, Jacobs AH, Zinnhardt B. A longitudinal PET/MR imaging study of colony stimulating factor-1 receptor-mediated microglia depletion in experimental stroke. J Nucl Med 2021; 63:446-452. [PMID: 34168016 PMCID: PMC8978197 DOI: 10.2967/jnumed.121.262279] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/27/2021] [Indexed: 11/23/2022] Open
Abstract
Microglia-induced neuroinflammation after stroke contributes to the exacerbation of postischemic damage but also supports neurorestorative events. Longitudinal molecular imaging of microglia-targeted therapies will support the assessment of target engagement, therapy efficacy, and deciphering of the mode of action. We investigated the effects of chronic colony-stimulating factor 1 receptor (CSF-1R) inhibitor–mediated microglia depletion on translocator protein (TSPO)–dependent neuroinflammation and cerebrovascular parameters using PET/MRI. Methods: Forty C57BL/6 mice underwent a 30-min transient occlusion of the middle cerebral artery and were randomly assigned to either a control group or a group treated with CSF-1R inhibitor (PLX5622). Eight mice per group were used for N,N-diethyl-2-(2-(4-(2-18F-fluoroethoxy) phenyl)5,7dimethylpyrazolo[1, 5a]pyrimidin-3-yl)acetamide (18F-DPA-714) (TSPO) PET imaging on days 7, 14, 21, and 30 after ischemia and behavioral tests before and after surgery. An extra group of 8 mice underwent MRI, including T2-weighted (infarct), perfusion-weighted (cerebral blood flow), and diffusion-weighted (water diffusion, cellular density) sequences, on days 1, 3, 7, 14, 21, and 30. Ex vivo analysis (immunoreactivity, gene expression) was performed to characterize the inflammatory environment. Results: We demonstrated that long-term CSF-1R inhibition transiently decreased the TSPO PET signal within the infarct. Residual TSPO activity was partly due to a potentially resistant Iba-1–positive cell populations with low CSF-1R and transmembrane 119 expression. The decrease in selected pro- and antiinflammatory marker expression suggested an apparent global dampening of the neuroinflammatory response. Furthermore, the temporal changes in the MRI parameters highlighted treatment-induced effects on reperfusion and tissue homeostasis, associated with impaired motor function at late stages. Conclusion: Longitudinal TSPO PET/MRI allows the assessment of target engagement and optimization of drug efficiency. PLX5622 has promising immunomodulatory effects, and the optimal therapeutic time window for its application needs to be defined.
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Affiliation(s)
| | - Amanda J Kiliaan
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Netherlands
| | | | - Lydia Wachsmuth
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University Hospital Munster, Germany
| | - Sven Hermann
- European Institute of Molecular Imaging, Germany
| | - Cornelius Faber
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University Hospital Munster, Germany
| | | | - Maximilian Wiesmann
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Netherlands
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49
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Yao C, Cao X, Yu B. Revascularization After Traumatic Spinal Cord Injury. Front Physiol 2021; 12:631500. [PMID: 33995118 PMCID: PMC8119644 DOI: 10.3389/fphys.2021.631500] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/06/2021] [Indexed: 12/12/2022] Open
Abstract
Traumatic spinal cord injury (SCI) is a complex pathological process. The initial mechanical damage is followed by a progressive secondary injury cascade. The injury ruptures the local microvasculature and disturbs blood-spinal cord barriers, exacerbating inflammation and tissue damage. Although endogenous angiogenesis is triggered, the new vessels are insufficient and often fail to function normally. Numerous blood vessel interventions, such as proangiogenic factor administration, gene modulation, cell transplantation, biomaterial implantation, and physical stimulation, have been applied as SCI treatments. Here, we briefly describe alterations and effects of the vascular system on local microenvironments after SCI. Therapies targeted at revascularization for SCI are also summarized.
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Affiliation(s)
- Chun Yao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Xuemin Cao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
| | - Bin Yu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, China
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50
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Dixon MA, Greferath U, Fletcher EL, Jobling AI. The Contribution of Microglia to the Development and Maturation of the Visual System. Front Cell Neurosci 2021; 15:659843. [PMID: 33967697 PMCID: PMC8102829 DOI: 10.3389/fncel.2021.659843] [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: 01/28/2021] [Accepted: 03/29/2021] [Indexed: 12/20/2022] Open
Abstract
Microglia, the resident immune cells of the central nervous system (CNS), were once considered quiescent cells that sat in readiness for reacting to disease and injury. Over the last decade, however, it has become clear that microglia play essential roles in maintaining the normal nervous system. The retina is an easily accessible part of the central nervous system and therefore much has been learned about the function of microglia from studies in the retina and visual system. Anatomically, microglia have processes that contact all synapses within the retina, as well as blood vessels in the major vascular plexuses. Microglia contribute to development of the visual system by contributing to neurogenesis, maturation of cone photoreceptors, as well as refining synaptic contacts. They can respond to neural signals and in turn release a range of cytokines and neurotrophic factors that have downstream consequences on neural function. Moreover, in light of their extensive contact with blood vessels, they are also essential for regulation of vascular development and integrity. This review article summarizes what we have learned about the role of microglia in maintaining the normal visual system and how this has helped in understanding their role in the central nervous system more broadly.
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Affiliation(s)
- Michael A Dixon
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
| | - Ursula Greferath
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
| | - Erica L Fletcher
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
| | - Andrew I Jobling
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, VIC, Australia
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