1
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Granzotto A, McQuade A, Chadarevian JP, Davtyan H, Sensi SL, Parker I, Blurton-Jones M, Smith IF. ER and SOCE Ca 2+ signals are not required for directed cell migration in human iPSC-derived microglia. Cell Calcium 2024; 123:102923. [PMID: 38970922 DOI: 10.1016/j.ceca.2024.102923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/29/2024] [Accepted: 06/12/2024] [Indexed: 07/08/2024]
Abstract
The central nervous system (CNS) is constantly surveilled by microglia, highly motile and dynamic cells deputed to act as the first line of immune defense in the brain and spinal cord. Alterations in the homeostasis of the CNS are detected by microglia that respond by extending their processes or - following major injuries - by migrating toward the affected area. Understanding the mechanisms controlling directed cell migration of microglia is crucial to dissect their responses to neuroinflammation and injury. We used a combination of pharmacological and genetic approaches to explore the involvement of calcium (Ca2+) signaling in the directed migration of human induced pluripotent stem cell (iPSC)-derived microglia challenged with a purinergic stimulus. This approach mimics cues originating from injury of the CNS. Unexpectedly, simultaneous imaging of microglia migration and intracellular Ca2+ changes revealed that this phenomenon does not require Ca2+ signals generated from the endoplasmic reticulum (ER) and store-operated Ca2+ entry (SOCE) pathways. Instead, we find evidence that human microglial chemotaxis to purinergic signals is mediated by cyclic AMP in a Ca2+-independent manner. These results challenge prevailing notions, with important implications in neurological conditions characterized by perturbation in Ca2+ homeostasis.
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Affiliation(s)
- Alberto Granzotto
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States; Center for Advanced Sciences and Technology (CAST), University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy; Department of Neuroscience, Imaging and Clinical Sciences, University G d'Annunzio of Chieti-Pescara, Chieti, Italy.
| | - Amanda McQuade
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, United States; Department of Neurobiology and Behavior, University of California, Irvine, CA, United States; Institute for Neurodegenerative Diseases, University of California, San Francisco, CA, United States
| | - Jean Paul Chadarevian
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, United States; Department of Neurobiology and Behavior, University of California, Irvine, CA, United States
| | - Hayk Davtyan
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, United States
| | - Stefano L Sensi
- Center for Advanced Sciences and Technology (CAST), University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy; Department of Neuroscience, Imaging and Clinical Sciences, University G d'Annunzio of Chieti-Pescara, Chieti, Italy; Institute for Advanced Biomedical Technologies (ITAB), "G. d'Annunzio" University, Chieti-Pescara, Italy
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, CA, United States; Department of Physiology and Biophysics, University of California, Irvine, CA, United States
| | - Mathew Blurton-Jones
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States; Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, United States; Department of Neurobiology and Behavior, University of California, Irvine, CA, United States; Institute for Immunology, University of California, Irvine, CA, United States
| | - Ian F Smith
- Department of Neurobiology and Behavior, University of California, Irvine, CA, United States
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2
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Izquierdo P, Jolivet RB, Attwell D, Madry C. Amyloid plaques and normal ageing have differential effects on microglial Ca 2+ activity in the mouse brain. Pflugers Arch 2024; 476:257-270. [PMID: 37966547 PMCID: PMC10791787 DOI: 10.1007/s00424-023-02871-3] [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: 08/10/2023] [Revised: 10/02/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
In microglia, changes in intracellular calcium concentration ([Ca2+]i) may regulate process motility, inflammasome activation, and phagocytosis. However, while neurons and astrocytes exhibit frequent spontaneous Ca2+ activity, microglial Ca2+ signals are much rarer and poorly understood. Here, we studied [Ca2+]i changes of microglia in acute brain slices using Fluo-4-loaded cells and mice expressing GCaMP5g in microglia. Spontaneous Ca2+ transients occurred ~ 5 times more frequently in individual microglial processes than in their somata. We assessed whether microglial Ca2+ responses change in Alzheimer's disease (AD) using AppNL-G-F knock-in mice. Proximity to Aβ plaques strongly affected microglial Ca2+ activity. Although spontaneous Ca2+ transients were unaffected in microglial processes, they were fivefold more frequent in microglial somata near Aβ plaques than in wild-type microglia. Microglia away from Aβ plaques in AD mice showed intermediate properties for morphology and Ca2+ responses, partly resembling those of wild-type microglia. By contrast, somatic Ca2+ responses evoked by tissue damage were less intense in microglia near Aβ plaques than in wild-type microglia, suggesting different mechanisms underlying spontaneous vs. damage-evoked Ca2+ signals. Finally, as similar processes occur in neurodegeneration and old age, we studied whether ageing affected microglial [Ca2+]i. Somatic damage-evoked Ca2+ responses were greatly reduced in microglia from old mice, as in the AD mice. In contrast to AD, however, old age did not alter the occurrence of spontaneous Ca2+ signals in microglial somata but reduced the rate of events in processes. Thus, we demonstrate distinct compartmentalised Ca2+ activity in microglia from healthy, aged and AD-like brains.
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Affiliation(s)
- Pablo Izquierdo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Renaud B Jolivet
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Paul-Henri Spaaklaan 1, 6229 EN, Maastricht, The Netherlands
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
| | - Christian Madry
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Institute of Neurophysiology, 10117, Berlin, Germany.
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3
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Granzotto A, McQuade A, Chadarevian JP, Davtyan H, Sensi SL, Parker I, Blurton-Jones M, Smith I. ER and SOCE Ca 2+ signals are not required for directed cell migration in human microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.18.576126. [PMID: 38293075 PMCID: PMC10827168 DOI: 10.1101/2024.01.18.576126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The central nervous system (CNS) is constantly surveilled by microglia, highly motile and dynamic cells deputed to act as the first line of immune defense in the brain and spinal cord. Alterations in the homeostasis of the CNS are detected by microglia that respond by migrating toward the affected area. Understanding the mechanisms controlling directed cell migration of microglia is crucial to dissect their responses to neuroinflammation and injury. We used a combination of pharmacological and genetic approaches to explore the involvement of calcium (Ca2+) signaling in the directed migration of induced pluripotent stem cell (iPSC)-derived microglia challenged with a purinergic stimulus. This approach mimics cues originating from injury of the CNS. Unexpectedly, simultaneous imaging of microglia migration and intracellular Ca2+ changes revealed that this phenomenon does not require Ca2+ signals generated from the endoplasmic reticulum (ER) and store-operated Ca2+ entry (SOCE) pathways. Instead, we find evidence that human microglial chemotaxis to purinergic signals is mediated by cyclic AMP in a Ca2+-independent manner. These results challenge prevailing notions, with important implications in neurological conditions characterized by perturbation in Ca2+ homeostasis.
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Affiliation(s)
- Alberto Granzotto
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States
- Center for Advanced Sciences and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, Chieti, Italy
- Department of Neuroscience, Imaging and Clinical Sciences, University G d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Amanda McQuade
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, United States
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
- Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, United States
| | - Jean Paul Chadarevian
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, United States
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
| | - Hayk Davtyan
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, United States
| | - Stefano L. Sensi
- Center for Advanced Sciences and Technology (CAST), University “G. d’Annunzio” of Chieti-Pescara, Chieti, Italy
- Department of Neuroscience, Imaging and Clinical Sciences, University G d’Annunzio of Chieti-Pescara, Chieti, Italy
- Institute for Advanced Biomedical Technologies (ITAB), “G. d’Annunzio” University, Chieti-Pescara, Italy
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
| | - Mathew Blurton-Jones
- UCI Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, United States
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
- Institute for Immunology, University of California, Irvine, Irvine, United States
| | - Ian Smith
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
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4
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Lia A, Sansevero G, Chiavegato A, Sbrissa M, Pendin D, Mariotti L, Pozzan T, Berardi N, Carmignoto G, Fasolato C, Zonta M. Rescue of astrocyte activity by the calcium sensor STIM1 restores long-term synaptic plasticity in female mice modelling Alzheimer's disease. Nat Commun 2023; 14:1590. [PMID: 36949142 PMCID: PMC10033875 DOI: 10.1038/s41467-023-37240-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 03/09/2023] [Indexed: 03/24/2023] Open
Abstract
Calcium dynamics in astrocytes represent a fundamental signal that through gliotransmitter release regulates synaptic plasticity and behaviour. Here we present a longitudinal study in the PS2APP mouse model of Alzheimer's disease (AD) linking astrocyte Ca2+ hypoactivity to memory loss. At the onset of plaque deposition, somatosensory cortical astrocytes of AD female mice exhibit a drastic reduction of Ca2+ signaling, closely associated with decreased endoplasmic reticulum Ca2+ concentration and reduced expression of the Ca2+ sensor STIM1. In parallel, astrocyte-dependent long-term synaptic plasticity declines in the somatosensory circuitry, anticipating specific tactile memory loss. Notably, we show that both astrocyte Ca2+ signaling and long-term synaptic plasticity are fully recovered by selective STIM1 overexpression in astrocytes. Our data unveil astrocyte Ca2+ hypoactivity in neocortical astrocytes as a functional hallmark of early AD stages and indicate astrocytic STIM1 as a target to rescue memory deficits.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gabriele Sansevero
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Angela Chiavegato
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Miriana Sbrissa
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Diana Pendin
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Letizia Mariotti
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, Padua, Italy
| | - Nicoletta Berardi
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (CNR), Padua, Italy.
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
| | - Cristina Fasolato
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (CNR), Padua, Italy.
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
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5
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Zhu T, Guo J, Wu Y, Lei T, Zhu J, Chen H, Kala S, Wong KF, Cheung CP, Huang X, Zhao X, Yang M, Sun L. The mechanosensitive ion channel Piezo1 modulates the migration and immune response of microglia. iScience 2023; 26:105993. [PMID: 36798430 PMCID: PMC9926228 DOI: 10.1016/j.isci.2023.105993] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/28/2022] [Accepted: 01/12/2023] [Indexed: 01/19/2023] Open
Abstract
Microglia are the brain's resident immune cells, performing surveillance to promote homeostasis and healthy functioning. While microglial chemical signaling is well-studied, mechanical cues regulating their function are less well-understood. Here, we investigate the role of the mechanosensitive ion channel Piezo1 in microglia migration, pro-inflammatory cytokine production, and stiffness sensing. In Piezo1 knockout transgenic mice, we demonstrated the functional expression of Piezo1 in microglia and identified genes whose expression was consequently affected. Functional assays revealed that Piezo1 deficiency in microglia enhanced migration toward amyloid β-protein, and decreased levels of pro-inflammatory cytokines produced upon stimulation by lipopolysaccharide, both in vitro and in vivo. The phenomenon could be mimicked or reversed chemically using a Piezo1-specific agonist or antagonist. Finally, we also showed that Piezo1 mediated the effect of substrate stiffness-induced migration and cytokine expression. Altogether, we show that Piezo1 is an important molecular mediator for microglia, its activation modulating microglial migration and immune responses.
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Affiliation(s)
- Ting Zhu
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Jinghui Guo
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Yong Wu
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Ting Lei
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Jiejun Zhu
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Hui Chen
- Biotherapy Centre, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China,Cell-gene Therapy Translational Medicine Research Centre, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shashwati Kala
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Kin Fung Wong
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Chi Pong Cheung
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Xiaohui Huang
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Xinyi Zhao
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Minyi Yang
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China
| | - Lei Sun
- Department of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR 999077, P. R. China,Corresponding author
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6
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Arnst N, Redolfi N, Lia A, Bedetta M, Greotti E, Pizzo P. Mitochondrial Ca 2+ Signaling and Bioenergetics in Alzheimer's Disease. Biomedicines 2022; 10:3025. [PMID: 36551781 PMCID: PMC9775979 DOI: 10.3390/biomedicines10123025] [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: 11/07/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Alzheimer's disease (AD) is a hereditary and sporadic neurodegenerative illness defined by the gradual and cumulative loss of neurons in specific brain areas. The processes that cause AD are still under investigation and there are no available therapies to halt it. Current progress puts at the forefront the "calcium (Ca2+) hypothesis" as a key AD pathogenic pathway, impacting neuronal, astrocyte and microglial function. In this review, we focused on mitochondrial Ca2+ alterations in AD, their causes and bioenergetic consequences in neuronal and glial cells, summarizing the possible mechanisms linking detrimental mitochondrial Ca2+ signals to neuronal death in different experimental AD models.
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Affiliation(s)
- Nikita Arnst
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
| | - Nelly Redolfi
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
| | - Annamaria Lia
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
| | - Martina Bedetta
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
| | - Elisa Greotti
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Padova Neuroscience Center (PNC), University of Padova, 35131 Padua, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padova, 35131 Padua, Italy
- Neuroscience Institute, Italian National Research Council (CNR), 35131 Padua, Italy
- Study Centre for Neurodegeneration (CESNE), University of Padova, 35131 Padua, Italy
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7
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Hübschmann V, Korkut-Demirbaş M, Siegert S. Assessing human iPSC-derived microglia identity and function by immunostaining, phagocytosis, calcium activity, and inflammation assay. STAR Protoc 2022; 3:101866. [PMID: 36595902 PMCID: PMC9678782 DOI: 10.1016/j.xpro.2022.101866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/28/2022] [Accepted: 10/28/2022] [Indexed: 11/19/2022] Open
Abstract
To understand how potential gene manipulations affect in vitro microglia, we provide a set of short protocols to evaluate microglia identity and function. We detail steps for immunostaining to determine microglia identity. We describe three functional assays for microglia: phagocytosis, calcium response following ATP stimulation, and cytokine expression upon inflammatory stimuli. We apply these protocols to human induced-pluripotent-stem-cell (hiPSC)-derived microglia, but they can be also applied to other in vitro microglial models including primary mouse microglia. For complete details on the use and execution of this protocol, please refer to Bartalska et al. (2022).1.
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Affiliation(s)
- Verena Hübschmann
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Medina Korkut-Demirbaş
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
| | - Sandra Siegert
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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8
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Role of Microglia and Astrocytes in Alzheimer’s Disease: From Neuroinflammation to Ca2+ Homeostasis Dysregulation. Cells 2022; 11:cells11172728. [PMID: 36078138 PMCID: PMC9454513 DOI: 10.3390/cells11172728] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia worldwide, with a complex, poorly understood pathogenesis. Cerebral atrophy, amyloid-β (Aβ) plaques, and neurofibrillary tangles represent the main pathological hallmarks of the AD brain. Recently, neuroinflammation has been recognized as a prominent feature of the AD brain and substantial evidence suggests that the inflammatory response modulates disease progression. Additionally, dysregulation of calcium (Ca2+) homeostasis represents another early factor involved in the AD pathogenesis, as intracellular Ca2+ concentration is essential to ensure proper cellular and neuronal functions. Although growing evidence supports the involvement of Ca2+ in the mechanisms of neurodegeneration-related inflammatory processes, scant data are available on its contribution in microglia and astrocytes functioning, both in health and throughout the AD continuum. Nevertheless, AD-related aberrant Ca2+ signalling in astrocytes and microglia is crucially involved in the mechanisms underpinning neuroinflammatory processes that, in turn, impact neuronal Ca2+ homeostasis and brain function. In this light, we attempted to provide an overview of the current understanding of the interactions between the glia cells-mediated inflammatory responses and the molecular mechanisms involved in Ca2+ homeostasis dysregulation in AD.
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9
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Jäntti H, Sitnikova V, Ishchenko Y, Shakirzyanova A, Giudice L, Ugidos IF, Gómez-Budia M, Korvenlaita N, Ohtonen S, Belaya I, Fazaludeen F, Mikhailov N, Gotkiewicz M, Ketola K, Lehtonen Š, Koistinaho J, Kanninen KM, Hernández D, Pébay A, Giugno R, Korhonen P, Giniatullin R, Malm T. Microglial amyloid beta clearance is driven by PIEZO1 channels. J Neuroinflammation 2022; 19:147. [PMID: 35706029 PMCID: PMC9199162 DOI: 10.1186/s12974-022-02486-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/15/2022] [Indexed: 02/06/2023] Open
Abstract
Background Microglia are the endogenous immune cells of the brain and act as sensors of pathology to maintain brain homeostasis and eliminate potential threats. In Alzheimer's disease (AD), toxic amyloid beta (Aβ) accumulates in the brain and forms stiff plaques. In late-onset AD accounting for 95% of all cases, this is thought to be due to reduced clearance of Aβ. Human genome-wide association studies and animal models suggest that reduced clearance results from aberrant function of microglia. While the impact of neurochemical pathways on microglia had been broadly studied, mechanical receptors regulating microglial functions remain largely unexplored. Methods Here we showed that a mechanotransduction ion channel, PIEZO1, is expressed and functional in human and mouse microglia. We used a small molecule agonist, Yoda1, to study how activation of PIEZO1 affects AD-related functions in human induced pluripotent stem cell (iPSC)-derived microglia-like cells (iMGL) under controlled laboratory experiments. Cell survival, metabolism, phagocytosis and lysosomal activity were assessed using real-time functional assays. To evaluate the effect of activation of PIEZO1 in vivo, 5-month-old 5xFAD male mice were infused daily with Yoda1 for two weeks through intracranial cannulas. Microglial Iba1 expression and Aβ pathology were quantified with immunohistochemistry and confocal microscopy. Published human and mouse AD datasets were used for in-depth analysis of PIEZO1 gene expression and related pathways in microglial subpopulations. Results We show that PIEZO1 orchestrates Aβ clearance by enhancing microglial survival, phagocytosis, and lysosomal activity. Aβ inhibited PIEZO1-mediated calcium transients, whereas activation of PIEZO1 with a selective agonist, Yoda1, improved microglial phagocytosis resulting in Aβ clearance both in human and mouse models of AD. Moreover, PIEZO1 expression was associated with a unique microglial transcriptional phenotype in AD as indicated by assessment of cellular metabolism, and human and mouse single-cell datasets. Conclusion These results indicate that the compromised function of microglia in AD could be improved by controlled activation of PIEZO1 channels resulting in alleviated Aβ burden. Pharmacological regulation of these mechanoreceptors in microglia could represent a novel therapeutic paradigm for AD. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02486-y.
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Affiliation(s)
- Henna Jäntti
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Valeriia Sitnikova
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Yevheniia Ishchenko
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.,Departments of Molecular Biophysics and Biochemistry and Neuroscience, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Anastasia Shakirzyanova
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Luca Giudice
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.,Department of Computer Science, University of Verona, 37134, Verona, Italy
| | - Irene F Ugidos
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Mireia Gómez-Budia
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Nea Korvenlaita
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Sohvi Ohtonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Irina Belaya
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Feroze Fazaludeen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Nikita Mikhailov
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Maria Gotkiewicz
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Kirsi Ketola
- Institute of Biomedicine, University of Eastern Finland, 70210, Kuopio, Finland
| | - Šárka Lehtonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Jari Koistinaho
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.,Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Katja M Kanninen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Damian Hernández
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia
| | - Alice Pébay
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Rosalba Giugno
- Department of Computer Science, University of Verona, 37134, Verona, Italy
| | - Paula Korhonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Rashid Giniatullin
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Tarja Malm
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.
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Cheng J, Dong Y, Ma J, Pan R, Liao Y, Kong X, Li X, Li S, Chen P, Wang L, Yu Y, Yuan Z. Microglial Calhm2 regulates neuroinflammation and contributes to Alzheimer's disease pathology. SCIENCE ADVANCES 2021; 7:7/35/eabe3600. [PMID: 34433553 PMCID: PMC8386937 DOI: 10.1126/sciadv.abe3600] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease in the world. Neuronal calcium dysfunction and microglial-mediated neuroinflammation are closely associated with the development of AD. However, it remains unknown whether calcium dysfunction contributes to microglial activation and, in turn, AD pathology in vivo. In this study, we demonstrated that the expression of calcium homeostasis modulator family protein 2 (Calhm2) is increased in an AD mouse model. In 5×FAD mice carrying five familial AD gene mutations, both conventional knockout of Calhm2 and conditional microglial knockout of Calhm2 significantly reduced amyloid β deposition, neuroinflammation, and cognitive impairments. Mechanistically, knockout of Calhm2 inhibited microglial proinflammatory activity but increased phagocytic activity, leading to restoration of the balance between inflammation and phagocytosis. In addition, knockout of Calhm2 reduced acute LPS-induced neuroinflammation. These results highlight an important role for Calhm2 in microglial activation and provide a potential therapeutic target for diseases related to microglia-mediated neuroinflammation.
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Affiliation(s)
- Jinbo Cheng
- Center on Translational Neuroscience, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China.
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Yuan Dong
- Department of Biochemistry, Medical College, Qingdao University, Qingdao, Shandong 266071, China
| | - Jun Ma
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Ruiyuan Pan
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Yajin Liao
- Center on Translational Neuroscience, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Xiangxi Kong
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Xiaoheng Li
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Shuoshuo Li
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
| | - Pingfang Chen
- School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Liang Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Influenza Research and Early-warning (CASCIRE), CAS-TWAS Center of Excellence for Emerging Infectious Diseases (CEEID), Chinese Academy of Sciences, Beijing 100101, China
| | - Ye Yu
- School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Zengqiang Yuan
- Center on Translational Neuroscience, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China.
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing 100850, China
- Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing 100069, China
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11
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Palomba NP, Martinello K, Cocozza G, Casciato S, Mascia A, Di Gennaro G, Morace R, Esposito V, Wulff H, Limatola C, Fucile S. ATP-evoked intracellular Ca 2+ transients shape the ionic permeability of human microglia from epileptic temporal cortex. J Neuroinflammation 2021; 18:44. [PMID: 33588880 PMCID: PMC7883449 DOI: 10.1186/s12974-021-02096-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/02/2021] [Indexed: 12/18/2022] Open
Abstract
Background Intracellular Ca2+ modulates several microglial activities, such as proliferation, migration, phagocytosis, and inflammatory mediator secretion. Extracellular ATP, the levels of which significantly change during epileptic seizures, activates specific receptors leading to an increase of intracellular free Ca2+ concentration ([Ca2+]i). Here, we aimed to functionally characterize human microglia obtained from cortices of subjects with temporal lobe epilepsy, focusing on the Ca2+-mediated response triggered by purinergic signaling. Methods Fura-2 based fluorescence microscopy was used to measure [Ca2+]i in primary cultures of human microglial cells obtained from surgical specimens. The perforated patch-clamp technique, which preserves the cytoplasmic milieu, was used to measure ATP-evoked Ca2+-dependent whole-cell currents. Results In human microglia extracellular ATP evoked [Ca2+]i increases depend on Ca2+ entry from the extracellular space and on Ca2+ mobilization from intracellular compartments. Extracellular ATP also induced a transient fivefold potentiation of the total transmembrane current, which was completely abolished when [Ca2+]i increases were prevented by removing external Ca2+ and using an intracellular Ca2+ chelator. TRAM-34, a selective KCa3.1 blocker, significantly reduced the ATP-induced current potentiation but did not abolish it. The removal of external Cl− in the presence of TRAM-34 further lowered the ATP-evoked effect. A direct comparison between the ATP-evoked mean current potentiation and mean Ca2+ transient amplitude revealed a linear correlation. Treatment of microglial cells with LPS for 48 h did not prevent the ATP-induced Ca2+ mobilization but completely abolished the ATP-mediated current potentiation. The absence of the Ca2+-evoked K+ current led to a less sustained ATP-evoked Ca2+ entry, as shown by the faster Ca2+ transient kinetics observed in LPS-treated microglia. Conclusions Our study confirms a functional role for KCa3.1 channels in human microglia, linking ATP-evoked Ca2+ transients to changes in membrane conductance, with an inflammation-dependent mechanism, and suggests that during brain inflammation the KCa3.1-mediated microglial response to purinergic signaling may be reduced. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02096-0.
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Affiliation(s)
| | | | | | | | | | | | | | - Vincenzo Esposito
- IRCCS Neuromed, Pozzilli, IS, Italy.,Department of Human Neurosciences, Sapienza Rome University, Rome, Italy
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Cristina Limatola
- IRCCS Neuromed, Pozzilli, IS, Italy.,Department of Physiology and Pharmacology "V. Erspamer", Sapienza Rome University, Rome, Italy
| | - Sergio Fucile
- IRCCS Neuromed, Pozzilli, IS, Italy.,Department of Physiology and Pharmacology "V. Erspamer", Sapienza Rome University, Rome, Italy
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12
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Hopp SC. Targeting microglia L-type voltage-dependent calcium channels for the treatment of central nervous system disorders. J Neurosci Res 2021; 99:141-162. [PMID: 31997405 PMCID: PMC9394523 DOI: 10.1002/jnr.24585] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/03/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+ ) is a ubiquitous mediator of a multitude of cellular functions in the central nervous system (CNS). Intracellular Ca2+ is tightly regulated by cells, including entry via plasma membrane Ca2+ permeable channels. Of specific interest for this review are L-type voltage-dependent Ca2+ channels (L-VDCCs), due to their pleiotropic role in several CNS disorders. Currently, there are numerous approved drugs that target L-VDCCs, including dihydropyridines. These drugs are safe and effective for the treatment of humans with cardiovascular disease and may also confer neuroprotection. Here, we review the potential of L-VDCCs as a target for the treatment of CNS disorders with a focus on microglia L-VDCCs. Microglia, the resident immune cells of the brain, have attracted recent attention for their emerging inflammatory role in several CNS diseases. Intracellular Ca2+ regulates microglia transition from a resting quiescent state to an "activated" immune-effector state and is thus a valuable target for manipulation of microglia phenotype. We will review the literature on L-VDCC expression and function in the CNS and on microglia in vitro and in vivo and explore the therapeutic landscape of L-VDCC-targeting agents at present and future challenges in the context of Alzheimer's disease, Parkinson's disease, Huntington's disease, neuropsychiatric diseases, and other CNS disorders.
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Affiliation(s)
- Sarah C. Hopp
- Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
- Department of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
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13
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Zhang I, Hu H. Store-Operated Calcium Channels in Physiological and Pathological States of the Nervous System. Front Cell Neurosci 2020; 14:600758. [PMID: 33328896 PMCID: PMC7732603 DOI: 10.3389/fncel.2020.600758] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Store-operated calcium channels (SOCs) are widely expressed in excitatory and non-excitatory cells where they mediate significant store-operated calcium entry (SOCE), an important pathway for calcium signaling throughout the body. While the activity of SOCs has been well studied in non-excitable cells, attention has turned to their role in neurons and glia in recent years. In particular, the role of SOCs in the nervous system has been extensively investigated, with links to their dysregulation found in a wide variety of neurological diseases from Alzheimer’s disease (AD) to pain. In this review, we provide an overview of their molecular components, expression, and physiological role in the nervous system and describe how the dysregulation of those roles could potentially lead to various neurological disorders. Although further studies are still needed to understand how SOCs are activated under physiological conditions and how they are linked to pathological states, growing evidence indicates that SOCs are important players in neurological disorders and could be potential new targets for therapies. While the role of SOCE in the nervous system continues to be multifaceted and controversial, the study of SOCs provides a potentially fruitful avenue into better understanding the nervous system and its pathologies.
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Affiliation(s)
- Isis Zhang
- Department of Anesthesiology, Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Huijuan Hu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
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14
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Luo L, Song S, Ezenwukwa CC, Jalali S, Sun B, Sun D. Ion channels and transporters in microglial function in physiology and brain diseases. Neurochem Int 2020; 142:104925. [PMID: 33248207 DOI: 10.1016/j.neuint.2020.104925] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/19/2022]
Abstract
Microglial cells interact with all components of the central nervous system (CNS) and are increasingly recognized to play essential roles during brain development, homeostasis and disease pathologies. Functions of microglia include maintaining tissue integrity, clearing cellular debris and dead neurons through the process of phagocytosis, and providing tissue repair by releasing anti-inflammatory cytokines and neurotrophic factors. Changes of microglial ionic homeostasis (Na+, Ca2+, K+, H+, Cl-) are important for microglial activation, including proliferation, migration, cytokine release and reactive oxygen species production, etc. These are mediated by ion channels and ion transporters in microglial cells. Here, we review the current knowledge about the role of major microglial ion channels and transporters, including several types of Ca2+ channels (store-operated Ca2+ entry (SOCE) channels, transient receptor potential (TRP) channels and voltage-gated Ca2+ channels (VGCCs)) and Na+ channels (voltage-gated Na+ channels (Nav) and acid-sensing ion channels (ASICs)), K+ channels (inward rectifier K+ channels (Kir), voltage-gated K+ channels (KV) and calcium-activated K+ channels (KCa)), proton channels (voltage-gated proton channel (Hv1)), and Cl- channels (volume (or swelling)-regulated Cl- channels (VRCCs) and chloride intracellular channels (CLICs)). In addition, ion transporter proteins such as Na+/Ca2+ exchanger (NCX), Na+-K+-Cl- cotransporter (NKCC1), and Na+/H+ exchanger (NHE1) are also involved in microglial function in physiology and brain diseases. We discussed microglial activation and neuroinflammation in relation to the ion channel/transporter stimulation under brain disease conditions and therapeutic aspects of targeting microglial ion channels/transporters for neurodegenerative disease, ischemic stroke, traumatic brain injury and neuropathic pain.
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Affiliation(s)
- Lanxin Luo
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | | | - Shayan Jalali
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Baoshan Sun
- Pólo DoisPortos, Instituto National de InvestigaçãoAgrária e Veterinária, I.P., Quinta da Almoinha, DoisPortos, 2565-191, Portugal.
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
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15
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Therapeutic Strategies to Target Calcium Dysregulation in Alzheimer's Disease. Cells 2020; 9:cells9112513. [PMID: 33233678 PMCID: PMC7699688 DOI: 10.3390/cells9112513] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, affecting millions of people worldwide. Unfortunately, none of the current treatments are effective at improving cognitive function in AD patients and, therefore, there is an urgent need for the development of new therapies that target the early cause(s) of AD. Intracellular calcium (Ca2+) regulation is critical for proper cellular and neuronal function. It has been suggested that Ca2+ dyshomeostasis is an upstream factor of many neurodegenerative diseases, including AD. For this reason, chemical agents or small molecules aimed at targeting or correcting this Ca2+ dysregulation might serve as therapeutic strategies to prevent the development of AD. Moreover, neurons are not alone in exhibiting Ca2+ dyshomeostasis, since Ca2+ disruption is observed in other cell types in the brain in AD. In this review, we examine the distinct Ca2+ channels and compartments involved in the disease mechanisms that could be potential targets in AD.
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16
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Hemonnot AL, Hua J, Ulmann L, Hirbec H. Microglia in Alzheimer Disease: Well-Known Targets and New Opportunities. Front Aging Neurosci 2019; 11:233. [PMID: 31543810 PMCID: PMC6730262 DOI: 10.3389/fnagi.2019.00233] [Citation(s) in RCA: 187] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/14/2019] [Indexed: 12/21/2022] Open
Abstract
Microglia are the resident macrophages of the central nervous system. They play key roles in brain development, and physiology during life and aging. Equipped with a variety of molecular sensors and through the various functions they can fulfill, they are critically involved in maintaining the brain’s homeostasis. In Alzheimer disease (AD), microglia reaction was initially thought to be incidental and triggered by amyloid deposits and dystrophic neurites. However, recent genome-wide association studies have established that the majority of AD risk loci are found in or near genes that are highly and sometimes uniquely expressed in microglia. This leads to the concept of microglia being critically involved in the early steps of the disease and identified them as important potential therapeutic targets. Whether microglia reaction is beneficial, detrimental or both to AD progression is still unclear and the subject of intense debate. In this review, we are presenting a state-of-knowledge report intended to highlight the variety of microglial functions and pathways shown to be critically involved in AD progression. We first address both the acquisition of new functions and the alteration of their homeostatic roles by reactive microglia. Second, we propose a summary of new important parameters currently emerging in the field that need to be considered to identify relevant microglial targets. Finally, we discuss the many obstacles in designing efficient therapeutic strategies for AD and present innovative technologies that may foster our understanding of microglia roles in the pathology. Ultimately, this work aims to fly over various microglial functions to make a general and reliable report of the current knowledge regarding microglia’s involvement in AD and of the new research opportunities in the field.
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Affiliation(s)
- Anne-Laure Hemonnot
- Institute for Functional Genomics (IGF), University of Montpellier, Centre National de la Recherche Scientififique, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
| | - Jennifer Hua
- Institute for Functional Genomics (IGF), University of Montpellier, Centre National de la Recherche Scientififique, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
| | - Lauriane Ulmann
- Institute for Functional Genomics (IGF), University of Montpellier, Centre National de la Recherche Scientififique, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
| | - Hélène Hirbec
- Institute for Functional Genomics (IGF), University of Montpellier, Centre National de la Recherche Scientififique, Institut National de la Santé et de la Recherche Médicale, Montpellier, France
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17
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Lue LF, Beach TG, Walker DG. Alzheimer's Disease Research Using Human Microglia. Cells 2019; 8:cells8080838. [PMID: 31387311 PMCID: PMC6721636 DOI: 10.3390/cells8080838] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 02/06/2023] Open
Abstract
Experimental studies of neuroinflammation in Alzheimer's disease (AD) have mostly investigated microglia, the brain-resident macrophages. This review focused on human microglia obtained at rapid autopsies. Studies employing methods to isolate and culture human brain microglia in high purity for experimental studies were discussed. These methods were employed to isolate human microglia for investigation of a number of features of neuroinflammation, including activation phenotypes, neurotoxicity, responses to abnormal aggregated proteins such as amyloid beta, phagocytosis, and the effects of aging and disease on microglia cellular properties. In recent years, interest in human microglia and neuroinflammation has been renewed due to the identification of inflammation-related AD genetic risk factors, in particular the triggering receptor expressed on myeloid cells (TREM)-2. Because of the difficulties in developing effective treatments for AD, there has been a general need for greater understanding of the functions of microglia in normal and AD brains. While most experimental studies on neuroinflammation have employed rodent microglia, this review considered the role of human microglia in experimental studies. This review focused on the development of in vitro methodology for the culture of postmortem human microglia and the key findings obtained from experimental studies with these cells.
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Affiliation(s)
- Lih-Fen Lue
- Banner Sun Health Research Institute, Sun City, AZ, 85351, USA.
- Neurodegenerative Disease Research Center and School of Life Sciences, Arizona State University, Tempe, AZ 84027, USA.
| | - Thomas G Beach
- Banner Sun Health Research Institute, Sun City, AZ, 85351, USA
| | - Douglas G Walker
- Neurodegenerative Disease Research Center and School of Life Sciences, Arizona State University, Tempe, AZ 84027, USA
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu 520, Japan
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18
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Mustaly-Kalimi S, Littlefield AM, Stutzmann GE. Calcium Signaling Deficits in Glia and Autophagic Pathways Contributing to Neurodegenerative Disease. Antioxid Redox Signal 2018; 29:1158-1175. [PMID: 29634342 DOI: 10.1089/ars.2017.7266] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
SIGNIFICANCE Numerous cellular processes and signaling mechanisms have been identified that contribute to Alzheimer's disease (AD) pathology; however, a comprehensive or unifying pathway that binds together the major disease features remains elusive. As an upstream mechanism, altered calcium (Ca2+) signaling is a common driving force for many pathophysiological events that emerge during normal aging and development of neurodegenerative disease. Recent Advances: Over the previous three decades, accumulated evidence has validated the concept that intracellular Ca2+ dysregulation is centrally involved in AD pathogenesis, including the aggregation of pathogenic β-amyloid (Aβ) and phospho-τ species, synapse loss and dysfunction, cognitive impairment, and neurotoxicity. CRITICAL ISSUES Although neuronal Ca2+ signaling within the cytosol and endoplasmic reticulum (ER) has been well studied, other critical central nervous system-resident cell types affected by aberrant Ca2+ signaling, such as astrocytes and microglia, have not been considered as thoroughly. In addition, certain intracellular Ca2+-harboring organelles have been well studied, such as the ER and mitochondria; however other critical Ca2+-regulated organelles, such as lysosomes and autophagosomes, have only more recently been investigated. In this review, we examine Ca2+ dysregulation in microglia and astrocytes, as well as key intracellular organelles important for cellular maintenance and protein handling. Ca2+ dysregulation within these non-neuronal cells and organelles is hypothesized to disrupt the effective clearance of misaggregated proteins and cellular signaling pathways needed for memory networks. FUTURE DIRECTIONS Overall, we aim to explore how these disrupted mechanisms could be involved in AD pathology and consider their role as potential therapeutic targets. Antioxid. Redox Signal. 29, 1158-1175.
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Affiliation(s)
- Sarah Mustaly-Kalimi
- 1 Department of Neuroscience, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science , North Chicago, Illinois
| | - Alyssa M Littlefield
- 1 Department of Neuroscience, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science , North Chicago, Illinois
| | - Grace E Stutzmann
- 2 Department of Neuroscience, The Chicago Medical School, Rosalind Franklin University of Medicine and Science , North Chicago, Illinois
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19
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Nirzhor SSR, Khan RI, Neelotpol S. The Biology of Glial Cells and Their Complex Roles in Alzheimer's Disease: New Opportunities in Therapy. Biomolecules 2018; 8:biom8030093. [PMID: 30201881 PMCID: PMC6164719 DOI: 10.3390/biom8030093] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 08/28/2018] [Accepted: 09/06/2018] [Indexed: 01/01/2023] Open
Abstract
Even though Alzheimer's disease (AD) is of significant interest to the scientific community, its pathogenesis is very complicated and not well-understood. A great deal of progress has been made in AD research recently and with the advent of these new insights more therapeutic benefits may be identified that could help patients around the world. Much of the research in AD thus far has been very neuron-oriented; however, recent studies suggest that glial cells, i.e., microglia, astrocytes, oligodendrocytes, and oligodendrocyte progenitor cells (NG2 glia), are linked to the pathogenesis of AD and may offer several potential therapeutic targets against AD. In addition to a number of other functions, glial cells are responsible for maintaining homeostasis (i.e., concentration of ions, neurotransmitters, etc.) within the central nervous system (CNS) and are crucial to the structural integrity of neurons. This review explores the: (i) role of glial cells in AD pathogenesis; (ii) complex functionalities of the components involved; and (iii) potential therapeutic targets that could eventually lead to a better quality of life for AD patients.
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20
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Haraguchi Y, Mizoguchi Y, Ohgidani M, Imamura Y, Murakawa-Hirachi T, Nabeta H, Tateishi H, Kato TA, Monji A. Donepezil suppresses intracellular Ca 2+ mobilization through the PI3K pathway in rodent microglia. J Neuroinflammation 2017; 14:258. [PMID: 29273047 PMCID: PMC5741946 DOI: 10.1186/s12974-017-1033-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/11/2017] [Indexed: 12/17/2022] Open
Abstract
Background Microglia are resident innate immune cells which release many factors including proinflammatory cytokines or nitric oxide (NO) when they are activated in response to immunological stimuli. Pathophysiology of Alzheimer’s disease (AD) is related to the inflammatory responses mediated by microglia. Intracellular Ca2+ signaling is important for microglial functions such as release of NO and cytokines. In addition, alteration of intracellular Ca2+ signaling underlies the pathophysiology of AD, while it remains unclear how donepezil, an acetylcholinesterase inhibitor, affects intracellular Ca2+ mobilization in microglial cells. Methods We examined whether pretreatment with donepezil affects the intracellular Ca2+ mobilization using fura-2 imaging and tested the effects of donepezil on phagocytic activity by phagocytosis assay in rodent microglial cells. Results In this study, we observed that pretreatment with donepezil suppressed the TNFα-induced sustained intracellular Ca2+ elevation in both rat HAPI and mouse primary microglial cells. On the other hand, pretreatment with donepezil did not suppress the mRNA expression of both TNFR1 and TNFR2 in rodent microglia we used. Pretreatment with acetylcholine but not donepezil suppressed the TNFα-induced intracellular Ca2+ elevation through the nicotinic α7 receptors. In addition, sigma 1 receptors were not involved in the donepezil-induced suppression of the TNFα-mediated intracellular Ca2+ elevation. Pretreatment with donepezil suppressed the TNFα-induced intracellular Ca2+ elevation through the PI3K pathway in rodent microglial cells. Using DAF-2 imaging, we also found that pretreatment with donepezil suppressed the production of NO induced by TNFα treatment and the PI3K pathway could be important for the donepezil-induced suppression of NO production in rodent microglial cells. Finally, phagocytosis assay showed that pretreatment with donepezil promoted phagocytic activity of rodent microglial cells through the PI3K but not MAPK/ERK pathway. Conclusions These suggest that donepezil could directly modulate the microglial function through the PI3K pathway in the rodent brain, which might be important to understand the effect of donepezil in the brain. Electronic supplementary material The online version of this article (10.1186/s12974-017-1033-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yoshinori Haraguchi
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Yoshito Mizoguchi
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan.
| | - Masahiro Ohgidani
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yoshiomi Imamura
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Toru Murakawa-Hirachi
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Hiromi Nabeta
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Hiroshi Tateishi
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
| | - Takahiro A Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Akira Monji
- Department of Psychiatry, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, 849-8501, Japan
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21
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Tvrdik P, Kalani MYS. In Vivo Imaging of Microglial Calcium Signaling in Brain Inflammation and Injury. Int J Mol Sci 2017; 18:ijms18112366. [PMID: 29117112 PMCID: PMC5713335 DOI: 10.3390/ijms18112366] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 11/01/2017] [Accepted: 11/04/2017] [Indexed: 12/20/2022] Open
Abstract
Microglia, the innate immune sentinels of the central nervous system, are the most dynamic cells in the brain parenchyma. They are the first responders to insult and mediate neuroinflammation. Following cellular damage, microglia extend their processes towards the lesion, modify their morphology, release cytokines and other mediators, and eventually migrate towards the damaged area and remove cellular debris by phagocytosis. Intracellular Ca2+ signaling plays important roles in many of these functions. However, Ca2+ in microglia has not been systematically studied in vivo. Here we review recent findings using genetically encoded Ca2+ indicators and two-photon imaging, which have enabled new insights into Ca2+ dynamics and signaling pathways in large populations of microglia in vivo. These new approaches will help to evaluate pre-clinical interventions and immunomodulation for pathological brain conditions such as stroke and neurodegenerative diseases.
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Affiliation(s)
- Petr Tvrdik
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
| | - M Yashar S Kalani
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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Mizoguchi Y, Monji A. TRPC Channels and Brain Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 976:111-121. [DOI: 10.1007/978-94-024-1088-4_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Savchenko E, Malm T, Konttinen H, Hämäläinen RH, Guerrero-Toro C, Wojciechowski S, Giniatullin R, Koistinaho J, Magga J. Aβ and Inflammatory Stimulus Activate Diverse Signaling Pathways in Monocytic Cells: Implications in Retaining Phagocytosis in Aβ-Laden Environment. Front Cell Neurosci 2016; 10:279. [PMID: 27994540 PMCID: PMC5136556 DOI: 10.3389/fncel.2016.00279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/21/2016] [Indexed: 12/21/2022] Open
Abstract
Background: Accumulation of amyloid β (Aβ) is one of the main hallmarks of Alzheimer’s disease (AD). The enhancement of Aβ clearance may provide therapeutic means to restrict AD pathology. The cellular responses to different forms of Aβ in monocytic cells are poorly known. We aimed to study whether different forms of Aβ induce inflammatory responses in monocytic phagocytes and how Aβ may affect monocytic cell survival and function to retain phagocytosis in Aβ-laden environment. Methods: Monocytic cells were differentiated from bone marrow hematopoietic stem cells (HSC) in the presence of macrophage-colony stimulating factor. Monocytic cells were stimulated with synthetic Aβ42 and intracellular calcium responses were recorded with calcium imaging. The formation of reactive oxygen species (ROS), secretion of cytokines and cell viability were also assessed. Finally, monocytic cells were introduced to native Aβ deposits ex vivo and the cellular responses in terms of cell viability, pro-inflammatory activation and phagocytosis were determined. The ability of monocytic cells to phagocytose Aβ plaques was determined after intrahippocampal transplantation in vivo. Results: Freshly solubilized Aβ induced calcium oscillations, which persisted after removal of the stimulus. After few hours of aggregation, Aβ was not able to induce oscillations in monocytic cells. Instead, lipopolysaccharide (LPS) induced calcium responses divergent from Aβ-induced response. Furthermore, while LPS induced massive production of pro-inflammatory cytokines, neither synthetic Aβ species nor native Aβ deposits were able to induce pro-inflammatory activation of monocytic cells, contrary to primary microglia. Finally, monocytic cells retained their viability in the presence of Aβ and exhibited phagocytic activity towards native fibrillar Aβ deposits and congophilic Aβ plaques. Conclusion: Monocytic cells carry diverse cellular responses to Aβ and inflammatory stimulus LPS. Even though Aβ species cause specific responses in calcium signaling, they completely lack the ability to induce pro-inflammatory phenotype of monocytic cells. Monocytes retain their viability and function in Aβ-laden brain.
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Affiliation(s)
- Ekaterina Savchenko
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Tarja Malm
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Henna Konttinen
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Riikka H Hämäläinen
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Cindy Guerrero-Toro
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Sara Wojciechowski
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Rashid Giniatullin
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Jari Koistinaho
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland Kuopio, Finland
| | - Johanna Magga
- Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern FinlandKuopio, Finland; Department of Pharmacology and Toxicology, Research Unit of Biomedicine, University of OuluOulu, Finland
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Agostini M, Fasolato C. When, where and how? Focus on neuronal calcium dysfunctions in Alzheimer's Disease. Cell Calcium 2016; 60:289-298. [PMID: 27451385 DOI: 10.1016/j.ceca.2016.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD), since its characterization as a precise form of dementia with its own pathological hallmarks, has captured scientists' attention because of its complexity. The last 30 years have been filled with discoveries regarding the elusive aetiology of this disease and, thanks to advances in molecular biology and live imaging techniques, we now know that an important role is played by calcium (Ca2+). Ca2+, as ubiquitous second messenger, regulates a vast variety of cellular processes, from neuronal excitation and communication, to muscle fibre contraction and hormone secretion, with its action spanning a temporal scale that goes from microseconds to hours. It is therefore very challenging to conceive a single hypothesis that can integrate the numerous findings on this issue with those coming from the classical fields of AD research such as amyloid-beta (Aβ) and tau pathology. In this contribution, we will focus our attention on the Ca2+ hypothesis of AD, dissecting it, as much as possible, in its subcellular localization, where the Ca2+ signal meets its specificity. We will also follow the temporal evolution of the Ca2+ hypothesis, providing some of the most updated discoveries. Whenever possible, we will link the findings regarding Ca2+ dysfunction to the other players involved in AD pathogenesis, hoping to provide a crossover body of evidence, useful to amplify the knowledge that will lead towards the discovery of an effective therapy.
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Affiliation(s)
- Mario Agostini
- Department of Biomedical Sciences, University of Padua, Italy.
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25
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Park JH, Kim JN, Jang BC, Im SS, Song DK, Bae JH. Glucosamine suppresses platelet-activating factor-induced activation of microglia through inhibition of store-operated calcium influx. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 42:1-8. [PMID: 26745504 DOI: 10.1016/j.etap.2015.12.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 12/17/2015] [Accepted: 12/19/2015] [Indexed: 06/05/2023]
Abstract
Microglia activation and subsequent release of inflammatory mediators are implicated in the pathophysiology of neurodegenerative diseases. Platelet-activating factor (PAF), a potent lipid mediator synthesized by microglia, is known to stimulate microglia functional responses. In this study, we determined that endogenous PAF exert autocrine effects on microglia activation, as well as the underlying mechanism involved. We also investigated the effect of D-glucosamine (GlcN) on PAF-induced cellular activation in human HMO6 microglial cells. PAF induced sustained intracellular Ca(2+) ([Ca(2+)]i) increase through store-operated Ca(2+) channels (SOC) and reactive oxygen species (ROS) generation. PAF also induced pro-inflammatory markers through NFκB/COX-2 signaling. GlcN significantly inhibited PAF-induced Ca(2+) influx and ROS generation without significant cytotoxicity. GlcN downregulated excessive expression of pro-inflammatory markers and promoted filopodia formation through NFκB/COX-2 inhibition in PAF-stimulated HMO6 cells. Taken together, these data suggest that GlcN may offer substantial therapeutic potential for treating inflammatory and neurodegenerative diseases accompanied by microglial activation.
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Affiliation(s)
- Jae-Hyung Park
- Department of Physiology, Keimyung University School of Medicine, Daegu, South Korea
| | - Jeong-Nam Kim
- Department of Physiology, Keimyung University School of Medicine, Daegu, South Korea
| | - Byeong-Churl Jang
- Department of Molecular Medicine, Keimyung University School of Medicine, Daegu, South Korea
| | - Seung-Soon Im
- Department of Physiology, Keimyung University School of Medicine, Daegu, South Korea
| | - Dae-Kyu Song
- Department of Physiology, Keimyung University School of Medicine, Daegu, South Korea
| | - Jae-Hoon Bae
- Department of Physiology, Keimyung University School of Medicine, Daegu, South Korea.
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Paeoniflorin attenuates Aβ1-42-induced inflammation and chemotaxis of microglia in vitro and inhibits NF-κB- and VEGF/Flt-1 signaling pathways. Brain Res 2015; 1618:149-58. [PMID: 26049130 DOI: 10.1016/j.brainres.2015.05.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 03/25/2015] [Accepted: 05/26/2015] [Indexed: 01/08/2023]
Abstract
Alzheimer׳s disease (AD) is a neurodegenerative disease with elusive pathogenesis, which accounts for most cases of dementia in the aged population. It has been reported that persistent inflammatory responses and excessive chemotaxis of microglia stimulated by beta-amyloid (Aβ) oligomers in the brain may accelerate the progression of AD. The present study was conducted to explore whether paeoniflorin (PF), a water-soluble monoterpene glycoside isolated from the root of Paeonia lactiflora Pallas, could attenuate Aβ1-42-induced toxic effects on primary and BV-2 microglial cells in vitro. Our data showed that PF pretreatment inhibited Aβ1-42-induced production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in rodent microglia. Also, the nuclear translocation of nuclear factor kappa B (NF-κB) subunit p65 and the phosphorylation of NF-κB inhibitor alpha (IκBα) in Aβ1-42-stimulated microglial cells were suppressed by PF administration. Moreover, PF treatment reduced the release of chemokine (C-X-C motif) ligand 1 (CXCL1) and chemokine (C-C motif) ligand 2 (CCL-2) from Aβ1-42-stimulated microglia. Additionally, application of PF inhibited the increases in vascular endothelial growth factor (VEGF) and VEGF receptor 1 (Flt-1) triggered by Aβ1-42, and resulted in a concomitant reduction in microglial chemotaxis. Restoration of VEGF was noted to counteract the inhibitory effect of PF, suggesting that PF mitigated Aβ1-42-elicited microglial migration at least partly by suppressing the VEGF/Flt-1 axis. In summary, in presence of Aβ1-42, PF pretreatment inhibited the excessive microglial activation and chemotaxis.
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27
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Chantong B, Kratschmar DV, Lister A, Odermatt A. Inhibition of metabotropic glutamate receptor 5 induces cellular stress through pertussis toxin-sensitive Gi-proteins in murine BV-2 microglia cells. J Neuroinflammation 2014; 11:190. [PMID: 25407356 PMCID: PMC4240888 DOI: 10.1186/s12974-014-0190-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/30/2014] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Activation of metabotropic glutamate receptor 5 (mGluR5) by (RS)-2-chloro-5-hydroxyphenylglycine (CHPG) was shown to suppress microglia activation and decrease the release of associated pro-inflammatory mediators. In contrast, the consequences of mGluR5 inhibition are less well understood. Here, we used BV-2 cells, retaining key characteristics of primary mouse microglia, to examine whether mGluR5 inhibition by 2-methyl-6-(phenylethynyl)-pyridine (MPEP) enhances cellular stress and production of inflammatory mediators. METHODS BV-2 cells were treated with MPEP, followed by determination of cellular stress using fluorescent dyes and high-content imaging. The expression of inflammatory mediators, endoplasmic reticulum (ER)-stress markers and phosphorylated AMPKα was analyzed by quantitative PCR, ELISA and Western blotting. Additionally, phospholipase C (PLC) activity, cellular ATP content and changes in intracellular free Ca(2+) ([Ca(2+)]i) were measured using luminescence and fluorescence assays. RESULTS Treatment of BV-2 microglia with 100 μM MPEP increased intracellular reactive oxygen species (ROS), mitochondrial superoxide, mitochondrial mass as well as inducible nitric oxide synthase (iNOS) and IL-6 expression. Furthermore, MPEP reduced cellular ATP and induced AMPKα phosphorylation and the expression of the ER-stress markers CHOP, GRP78 and GRP96. The MPEP-dependent effects were preceded by a rapid concentration-dependent elevation of [Ca(2+)]i, following Ca(2+) release from the ER, mainly via inositol triphosphate-induced receptors (IP3R). The MPEP-induced ER-stress could be blocked by pretreatment with the chemical chaperone 4-phenylbutyrate and the Ca(2+) chelator BAPTA-AM. Pretreatment with the AMPK agonist AICAR partially abolished, whilst the inhibitor compound C potentiated, the MPEP-dependent ER-stress. Importantly, the PLC inhibitor U-73122 and the Gi-protein inhibitor pertussis toxin (PTX) blocked the MPEP-induced increase in [Ca(2+)]i. Moreover, pretreatment of microglia with AICAR, BAPTA-AM, U-73122 and PTX prevented the MPEP-induced generation of oxidative stress and inflammatory mediators, further supporting a role for Gi-protein-mediated activation of PLC. CONCLUSIONS The results emphasize the potential pathophysiological role of mGluR5 antagonism in mediating oxidative stress, ER-stress and inflammation through a Ca(2+)-dependent pathway in microglia. The induction of cellular stress and inflammatory mediators involves PTX-sensitive Gi-proteins and subsequent activation of PLC, IP3R and Ca(2+) release from the ER.
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Affiliation(s)
- Boonrat Chantong
- Current address: Department of Preclinical Science and Applied Animal Science, Faculty of Veterinary Science, Mahidol University, Phutthamonthon, Nakhonpathom, Thailand.
| | - Denise V Kratschmar
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
| | - Adam Lister
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
| | - Alex Odermatt
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056, Basel, Switzerland.
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Gofman L, Cenna JM, Potula R. P2X4 receptor regulates alcohol-induced responses in microglia. J Neuroimmune Pharmacol 2014; 9:668-78. [PMID: 25135400 DOI: 10.1007/s11481-014-9559-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 07/28/2014] [Indexed: 12/18/2022]
Abstract
Mounting evidence indicates that alcohol-induced neuropathology may result from multicellular responses in which microglia cells play a prominent role. Purinergic receptor signaling plays a key role in regulating microglial function and, more importantly, mediates alcohol-induced effects. Our findings demonstrate that alcohol increases expression of P2X4 receptor (P2X4R), which alters the function of microglia, including calcium mobilization, migration and phagocytosis. Our results show a significant up-regulation of P2X4 gene expression as analyzed by real-time qPCR (***p < 0.002) and protein expression as analyzed by flow cytometry (**p < 0.004) in embryonic stem cell-derived microglial cells (ESdM) after 48 hours of alcohol treatment, as compared to untreated controls. Calcium mobilization in ethanol treated ESdM cells was found to be P2X4R dependent using 5-BDBD, a P2X4R selective antagonist. Alcohol decreased migration of microglia towards fractalkine (CX3CL1) by 75 % following 48 h of treatment compared to control (***p < 0.001). CX3CL1-dependent migration was confirmed to be P2X4 receptor-dependent using the antagonist 5-BDBD, which reversed the effects as compared to alcohol alone (***p < 0.001). Similarly, 48 h of alcohol treatment significantly decreased phagocytosis of microglia by 15 % compared to control (*p < 0.05). 5-BDBD pre-treatment prior to alcohol treatment significantly increased microglial phagocytosis (***p < 0.001). Blocking P2X4R signaling with 5-BDBD decreased the level of calcium mobilization compared to ethanol treatment alone. These findings demonstrate that P2X4 receptor may play a role in modulating microglial function in the context of alcohol abuse.
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Affiliation(s)
- Larisa Gofman
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, 3500 N. Broad Street, MERB 845A, Philadelphia, PA, 19140, USA
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29
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Network-wide dysregulation of calcium homeostasis in Alzheimer’s disease. Cell Tissue Res 2014; 357:427-38. [DOI: 10.1007/s00441-014-1798-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 01/09/2014] [Indexed: 12/19/2022]
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30
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Sharma P, Ping L. Calcium ion influx in microglial cells: physiological and therapeutic significance. J Neurosci Res 2014; 92:409-23. [PMID: 24464907 DOI: 10.1002/jnr.23344] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 11/09/2013] [Accepted: 11/12/2013] [Indexed: 01/16/2023]
Abstract
Microglial cells, the immunocompetent cells of the central nervous system (CNS), exhibit a resting phenotype under healthy conditions. In response to injury, however, they transform into an activated state, which is a hallmark feature of many CNS diseases. Factors or agents released from the neurons, blood vessels, and/or astrocytes could activate these cells, leading to their functional and structural modifications. Microglial cells are well equipped to sense environmental changes within the brain under both physiological and pathological conditions. Entry of calcium ions (Ca(2+)) plays a critical role in the process of microglial transformation; several channels and receptors have been identified on the surface of microglial cells. These include store-operated channel, Orai1, and its sensor protein, stromal interaction molecule 1 (STIM1), in microglial cells, and their functions are modulated under pathological stimulations. Transient receptor potential (TRP) channels and voltage- and ligand-gated channels (ionotropic and metabotropic receptors) are also responsible for Ca(2+) influx into the microglial cells. An elevation of intracellular Ca(2+) concentration subsequently regulates microglial cell functions by activating a diverse array of Ca(2+)-sensitive signaling cascades. Perturbed Ca(2+) homeostasis contributes to the progression of a number of CNS disorders. Thus, regulation of Ca(2+) entry into microglial cells could be a pharmacological target for several CNS-related pathological conditions. This Review addresses the recent insights into microglial cell Ca(2+) influx mechanisms, their roles in the regulation of functions, and alterations of Ca(2+) entry in specific CNS disorders.
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Affiliation(s)
- Purnima Sharma
- All India Institute of Medical Sciences-Physiology, Basni Industrial Area Phase II Jodhpur, Rajasthan, India
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31
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Analysis of calcium homeostasis in fresh lymphocytes from patients with sporadic Alzheimer's disease or mild cognitive impairment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1692-9. [DOI: 10.1016/j.bbamcr.2013.01.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 12/21/2012] [Accepted: 01/11/2013] [Indexed: 11/20/2022]
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Verkhratsky A, Parpura V. Store-operated calcium entry in neuroglia. Neurosci Bull 2013; 30:125-33. [PMID: 23677809 DOI: 10.1007/s12264-013-1343-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 02/14/2013] [Indexed: 11/30/2022] Open
Abstract
Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca(2+) signals that define the "Ca(2+) excitability" of glia. In mammalian glial cells the major source of Ca(2+) for this excitability is the lumen of the endoplasmic reticulum (ER), which is ultimately (re)filled from the extracellular space. This occurs via store-operated Ca(2+) entry (SOCE) which is supported by a specific signaling system connecting the ER with plasmalemmal Ca(2+) entry. Here, emptying of the ER Ca(2+) store is necessary and sufficient for the activation of SOCE, and without Ca(2+) influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca(2+) sensors, such as stromal interaction molecule, and possibly ER Ca(2+) pumps (of the SERCA type). There are at least two sets of plasmalemmal channels mediating SOCE, the Ca(2+)-release activated channels, Orai, and transient receptor potential (TRP) channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca(2+) signal observed following stimulation of metabotropic receptors on glial cells.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK,
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Brawek B, Garaschuk O. Microglial calcium signaling in the adult, aged and diseased brain. Cell Calcium 2013; 53:159-69. [PMID: 23395344 DOI: 10.1016/j.ceca.2012.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
Microglial cells are the resident immune cells of the CNS. They mediate innate immune response of the brain to injury, inflammation and neurodegenerative diseases. Apart from their role in disease they are critically involved in the development and plasticity-driven reorganization of neuronal networks and the homeostatic maintenance of brain tissue. Accumulating in vitro evidence suggests that executive functions of microglia are coupled to the intracellular Ca(2+) signaling of these cells. So far, however, very little is known about microglial Ca(2+) signaling in situ or in vivo, both in the healthy and in the diseased brain. Here, we summarize the recent in vivo/in situ findings and compare the properties of surveillant microglia in these preparations with those of microglia in vitro. The data suggest that surveillant microglia rarely show spontaneous Ca(2+) transients, express fewer functional receptors directly coupled to changes in the intracellular free Ca(2+) concentration on their surface, but vividly respond with Ca(2+) transients to cell or tissue damage in their microenvironment. Interestingly, some of these properties microglia share with monocytes engrafting in the brain under pathological conditions.
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Affiliation(s)
- Bianca Brawek
- Institute of Physiology II, Eberhard Karls University of Tuebingen, Keplerstr. 15, 72074 Tuebingen, Germany
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Boche D, Perry VH, Nicoll JAR. Review: Activation patterns of microglia and their identification in the human brain. Neuropathol Appl Neurobiol 2013; 39:3-18. [PMID: 23252647 DOI: 10.1111/nan.12011] [Citation(s) in RCA: 701] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 12/07/2012] [Indexed: 12/17/2022]
Affiliation(s)
- D. Boche
- Clinical Neurosciences; Clinical and Experimental Sciences; Faculty of Medicine; University of Southampton; Southampton; UK
| | - V. H. Perry
- Centre for Biological Sciences; Faculty of Natural and Environmental Science; University of Southampton; Southampton; UK
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Store-operated Ca2+ entry in hippocampal neurons: Regulation by protein tyrosine phosphatase PTP1B. Cell Calcium 2012; 53:125-38. [PMID: 23218930 DOI: 10.1016/j.ceca.2012.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 10/12/2012] [Accepted: 11/04/2012] [Indexed: 11/20/2022]
Abstract
Store operated Ca(2+) entry (SOCE) replenishes intracellular Ca(2+) stores and activates a number of intracellular signalling pathways. Whilst several molecular components forming store operated Ca(2+) channels (SOCC) have been identified, their modulation in neurons remains poorly understood. Here, we extend on our previous findings and show that neuronal SOCE is modulated by tyrosine phosphorylation. Cyclopiazonic acid induced SOCE was characterised in hippocampal cultures derived from forebrain specific protein tyrosine phosphatase 1B knockout (PTP1B KO) mice and wild type (WT) litter mates using Fura-2 Ca(2+) imaging. PTP1B KO cultures expressed elevated SOCE relative to WT cultures without changes in cytoplasmic Ca(2+) homeostasis or depolarisation-induced Ca(2+) influx. WT and PTP1B KO cultures displayed similar pharmacological sensitivities towards the SOCE inhibitors gadolinium and 2-aminoethoxydiphenyl borate, as well as the tyrosine kinase inhibitor Ag126 indicating an augmentation of native SOCCs by PTP1B. Following store depletion WT culture homogenates showed heightened phospho-tyrosine levels, an increase in Src tyrosine kinase activation and two minor PTP1B species. These data suggest tyrosine phosphorylation gating SOCE, and implicate PTP1B as a key regulatory enzyme. The involvement of PTP1B in SOCE and its relation to SOCC components and mechanism of regulation are discussed.
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36
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Farooqui AA, Farooqui T, Panza F, Frisardi V. Metabolic syndrome as a risk factor for neurological disorders. Cell Mol Life Sci 2012; 69:741-62. [PMID: 21997383 PMCID: PMC11115054 DOI: 10.1007/s00018-011-0840-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/08/2011] [Accepted: 09/15/2011] [Indexed: 02/07/2023]
Abstract
The metabolic syndrome is a cluster of common pathologies: abdominal obesity linked to an excess of visceral fat, insulin resistance, dyslipidemia and hypertension. At the molecular level, metabolic syndrome is accompanied not only by dysregulation in the expression of adipokines (cytokines and chemokines), but also by alterations in levels of leptin, a peptide hormone released by white adipose tissue. These changes modulate immune response and inflammation that lead to alterations in the hypothalamic 'bodyweight/appetite/satiety set point,' resulting in the initiation and development of metabolic syndrome. Metabolic syndrome is a risk factor for neurological disorders such as stroke, depression and Alzheimer's disease. The molecular mechanism underlying the mirror relationship between metabolic syndrome and neurological disorders is not fully understood. However, it is becoming increasingly evident that all cellular and biochemical alterations observed in metabolic syndrome like impairment of endothelial cell function, abnormality in essential fatty acid metabolism and alterations in lipid mediators along with abnormal insulin/leptin signaling may represent a pathological bridge between metabolic syndrome and neurological disorders such as stroke, Alzheimer's disease and depression. The purpose of this review is not only to describe the involvement of brain in the pathogenesis of metabolic syndrome, but also to link the pathogenesis of metabolic syndrome with neurochemical changes in stroke, Alzheimer's disease and depression to a wider audience of neuroscientists with the hope that this discussion will initiate more studies on the relationship between metabolic syndrome and neurological disorders.
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Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43221, USA.
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Jantaratnotai N, McGeer PL, McLarnon JG. Mechanisms of Mg2+ inhibition of BzATP-dependent Ca2+ responses in THP-1 monocytes. Brain Res 2012; 1442:1-8. [PMID: 22297175 DOI: 10.1016/j.brainres.2012.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 12/14/2011] [Accepted: 01/04/2012] [Indexed: 12/31/2022]
Abstract
We have recently reported effects of Mg2+ to confer neuroprotection against toxicity of purinergic stimulated microglia and THP-1 monocytes. To examine mechanisms underlying neuroprotection, we have studied Mg2+ modulation of transient changes in intracellular Ca2+ ([Ca2+]i) in THP-1 cells induced by P2X7R agonist 2',3'-[benzoyl-4-benzoyl]-ATP (BzATP). Application of BzATP caused a rapid transient increase in [Ca2+]i followed by a prolonged component. The time course of the secondary slower phase was significantly reduced with Ca2+-free extracellular solution, with treatment of THP-1 cells by the P2X7R antagonist, oxATP or with exposure of cells to the store-operated channel (SOC) inhibitor, SKF96365. These results suggest that Ca2+ influx, mediated by both the P2X7R or by SOC, contribute to the slow component of [Ca2+]i. Treatment of THP-1 cells with 10 mMMg2+ was highly effective in reducing the time course of BzATP-induced Ca2+ decay; unlike the other modulatory protocols, Mg2+ markedly inhibited the amplitudes of slow and rapid components. In addition, acute application of Mg2+ during BzATP-induced responses elicited in the presence of either oxATP or SKF96365 to block respective P2X7R and SOC contributions, rapidly attenuated [Ca2+]i to baseline levels. Priming of cells with the inflammatory stimulus LPS/IFN-γ markedly enhanced the slower, but not rapid, phase of BzATP-induced [Ca2+]i with application of 10 mMMg2+ inhibiting both components of response. A model is proposed to account for BzATP stimulation of both ionotropic P2XR and metabotropic P2YR which provides a mechanistic basis for elevated Mg2+ anti-inflammatory and neuroprotective actions in inflamed brain.
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Affiliation(s)
- Nattinee Jantaratnotai
- Department of Anesthesiology, Pharmacology and Therapeutics, 2176 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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Jantaratnotai N, McLarnon JG. Calcium dependence of purinergic subtype P2Y₁ receptor modulation of C6 glioma cell migration. Neurosci Lett 2011; 497:80-4. [PMID: 21540076 DOI: 10.1016/j.neulet.2011.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/12/2011] [Accepted: 04/12/2011] [Indexed: 10/18/2022]
Abstract
We have examined activation of purinergic P2Y₁ receptor-dependent Ca²⁺-signaling pathways in mediating C6 glioma cell migration. The administration of 2-methylthioadenosine 5'-diphosphate (2MeSADP), a selective agonist for P2Y₁R, induced marked increases in patterns of glioma migration in both scratch wound and Boyden chamber assays. Antagonism of P2Y₁R with either the broad spectrum purinergic blocker, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS) or the specific P2Y₁R antagonist, 2'-deoxy-N⁶-methyladenosine-3',5'-bisphosphate (MRS2179), significantly inhibited C6 cell migration. Calcium-sensitive spectrofluorometry showed 2MeSADP stimulation of glioma cells caused a biphasic change in intracellular Ca²⁺ ([Ca²⁺]i). The rapid transient phase was unchanged in Ca²⁺-free solution reflecting a [Ca²⁺]i component due to intracellular stores release subsequent to activation of a metabotropic P2Y subtype receptor. The secondary prolonged phase of [Ca²⁺]i was abolished in Ca²⁺-free solution or in glioma cells treated with the store-operated channel (SOC) blocker, SKF96365. Treatment of glioma with either MRS2179 or PPADS significantly attenuated both the rapid and prolonged phases of [Ca²⁺]i. These results suggest critical roles for activation of P2Y₁R in mediating glioma cell mobility and migration with changes in [Ca²⁺]i contributing as a mechanistic link between activated receptor and functional response. Our findings suggest that pharmacological modulation of metabotropic P2Y₁R-dependent signaling pathways may serve as a novel therapeutic procedure to slow glioma progression.
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Affiliation(s)
- Nattinee Jantaratnotai
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T1Z3 Canada
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Roberts-Thomson SJ, Peters AA, Grice DM, Monteith GR. ORAI-mediated calcium entry: mechanism and roles, diseases and pharmacology. Pharmacol Ther 2010; 127:121-30. [PMID: 20546784 DOI: 10.1016/j.pharmthera.2010.04.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 04/28/2010] [Indexed: 12/22/2022]
Abstract
ORAI1 is a protein located on the plasma membrane that acts as a calcium channel. Calcium enters via ORAI1 as a mechanism to refill the sarcoplasmic/endoplasmic reticulum calcium stores, the depletion of which can be detected by the sensor protein STIM1. Isoforms of these proteins ORAI2, ORAI3 and STIM2 also have roles in cellular calcium homeostasis but are less well characterized. This pathway of filling the calcium stores is termed store-operated calcium entry and while the pathway itself was proposed in 1986, the identity of the key molecular components was only discovered in 2005 and 2006. The characterization of the ORAI and STIM proteins has provided clearer information on some calcium-regulated pathways that are important in processes from gene transcription to immune cell function. Recent studies have also suggested the importance of the components of ORAI-mediated calcium entry in some diseases or processes significant in disease including the migration of breast cancer cells and thrombus formation. This review will provide a brief overview of ORAI-mediated calcium entry, its role in physiological and pathophysiological processes, as well as current and potential pharmacological modulators of the components of this important cellular calcium entry pathway.
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Amyloid β-peptide directly induces spontaneous calcium transients, delayed intercellular calcium waves and gliosis in rat cortical astrocytes. ASN Neuro 2010; 2:e00026. [PMID: 20001968 PMCID: PMC2810812 DOI: 10.1042/an20090035] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 11/23/2009] [Accepted: 12/08/2009] [Indexed: 12/14/2022] Open
Abstract
The contribution of astrocytes to the pathophysiology of AD (Alzheimer's disease) and the molecular and signalling mechanisms that potentially underlie them are still very poorly understood. However, there is mounting evidence that calcium dysregulation in astrocytes may be playing a key role. Intercellular calcium waves in astrocyte networks in vitro can be mechanically induced after Aβ (amyloid β-peptide) treatment, and spontaneously forming intercellular calcium waves have recently been shown in vivo in an APP (amyloid precursor protein)/PS1 (presenilin 1) Alzheimer's transgenic mouse model. However, spontaneous intercellular calcium transients and waves have not been observed in vitro in isolated astrocyte cultures in response to direct Aβ stimulation in the absence of potentially confounding signalling from other cell types. Here, we show that Aβ alone at relatively low concentrations is directly able to induce intracellular calcium transients and spontaneous intercellular calcium waves in isolated astrocytes in purified cultures, raising the possibility of a potential direct effect of Aβ exposure on astrocytes in vivo in the Alzheimer's brain. Waves did not occur immediately after Aβ treatment, but were delayed by many minutes before spontaneously forming, suggesting that intracellular signalling mechanisms required sufficient time to activate before intercellular effects at the network level become evident. Furthermore, the dynamics of intercellular calcium waves were heterogeneous, with distinct radial or longitudinal propagation orientations. Lastly, we also show that changes in the expression levels of the intermediate filament proteins GFAP (glial fibrillary acidic protein) and S100B are affected by Aβ-induced calcium changes differently, with GFAP being more dependent on calcium levels than S100B.
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Jantaratnotai N, Choi HB, McLarnon JG. ATP stimulates chemokine production via a store-operated calcium entry pathway in C6 glioma cells. BMC Cancer 2009; 9:442. [PMID: 20003523 PMCID: PMC2807438 DOI: 10.1186/1471-2407-9-442] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 12/15/2009] [Indexed: 11/25/2022] Open
Abstract
Background Glioma present as one of the most challenging cancers to treat, however, understanding of tumor cell biology is not well understood. Extracellular adenosine triphosphate (ATP) could serve as a critical signaling molecule regulating tumor development. This study has examined pharmacological modulation of calcium (Ca2+) entry through store-operated channels (SOC) on cellular expression and production of immune-cell mobilizing chemokines in ATP-stimulated C6 glioma cells. Methods Calcium spectrofluorometry was carried out to measure mobilization of intracellular Ca2+ [Ca2+]i following ATP stimulation of rat C6 glioma cells. Pretreatment with two inhibitors of SOC, SKF96365 or gadolinium, was used to examine for effects on [Ca2+]i. RT-PCR was performed to determine effects of purinergic stimulation on C6 cell expression of metabotropic P2Y receptors (P2YR) and the chemokines, monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8). ELISA was carried out to measure production of MCP-1 and IL-8 with ATP stimulation of glioma cells. Results Application of ATP (at 100 μM) to C6 glioma induced an increase in [Ca2+]i with the response exhibiting two components of decay. In the presence of the SOC inhibitors, SKF96365 or gadolinium, or with Ca2+-free solution, ATP responses lacked a slow phase suggesting the secondary component was due to SOC-mediated influx of Ca2+. RT-PCR confirmed expression of purinergic P2Y-subtype receptors in C6 cells which would serve as a precursor to activation of SOC. In addition, ATP-stimulated C6 cells showed enhanced expression of the chemokines, MCP-1 and IL-8, with SKF96365 or gadolinium effective in reducing chemokine expression. Gadolinium treatment of ATP-stimulated C6 cells was also found to inhibit the production of MCP-1 and IL-8. Conclusion These results suggest ATP-induced Ca2+ entry, mediated by activation of SOC in C6 glioma, as a mechanism leading to increased cellular expression and release of chemokines. Elevated levels of MCP-1 and IL-8 are predicted to enhance the mobility of tumor cells and promote recruitment of microglia into developing tumors thereby supporting tumor growth.
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Affiliation(s)
- Nattinee Jantaratnotai
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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Microglial VEGF receptor response is an integral chemotactic component in Alzheimer's disease pathology. J Neurosci 2009; 29:3-13. [PMID: 19129379 DOI: 10.1523/jneurosci.2888-08.2009] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We hypothesize that microglial chemotactic responses to amyloid-beta peptide (Abeta(1-42)) serve as an early and integral component of inflammatory response in Alzheimer's disease (AD) brain. This study reports a receptor for vascular endothelial growth factor (VEGF), termed VEGF-1 (Flt-1), subserves microglial chemotactic responses induced by Abeta(1-42) stimulation, in vivo and in vitro. Expression of Flt-1 was significantly increased in tissue obtained from AD patients [compared with tissue from nondemented (ND) individuals], in Abeta(1-42)-injected rat hippocampus, and in peptide-stimulated human microglia. Single and double immunohistochemical staining demonstrated marked immunoreactivity, for both Flt-1 and its ligand VEGF, in association with microglia and Abeta deposits in AD, but not ND, brain tissue. Functionally, treatment with anti-Flt-1 antibody was highly effective in inhibiting microglial mobility and chemotactic responses measured in vitro using a transwell migration assay. In vivo, transplanted enhanced green fluorescent protein (EGFP)-labeled microglia exhibited Flt-1-dependent chemotaxis induced by peptide injection with anti-Flt-1 effective in blocking migration of cells. Importantly, anti-Flt-1 reduction of microglial mobility was neuroprotective in peptide-injected hippocampus and associated with a significant increase in numbers of viable hippocampal neurons. The results of this study suggest critical functional roles for Flt-1 in mediating microglial chemotactic inflammatory responses which contribute to pathological conditions in AD brain.
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Stone TW, Ceruti S, Abbracchio MP. Adenosine receptors and neurological disease: neuroprotection and neurodegeneration. Handb Exp Pharmacol 2009:535-87. [PMID: 19639293 DOI: 10.1007/978-3-540-89615-9_17] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Adenosine receptors modulate neuronal and synaptic function in a range of ways that may make them relevant to the occurrence, development and treatment of brain ischemic damage and degenerative disorders. A(1) adenosine receptors tend to suppress neural activity by a predominantly presynaptic action, while A(2A) adenosine receptors are more likely to promote transmitter release and postsynaptic depolarization. A variety of interactions have also been described in which adenosine A(1) or A(2) adenosine receptors can modify cellular responses to conventional neurotransmitters or receptor agonists such as glutamate, NMDA, nitric oxide and P2 purine receptors. Part of the role of adenosine receptors seems to be in the regulation of inflammatory processes that often occur in the aftermath of a major insult or disease process. All of the adenosine receptors can modulate the release of cytokines such as interleukins and tumor necrosis factor-alpha from immune-competent leukocytes and glia. When examined directly as modifiers of brain damage, A(1) adenosine receptor (AR) agonists, A(2A)AR agonists and antagonists, as well as A(3)AR antagonists, can protect against a range of insults, both in vitro and in vivo. Intriguingly, acute and chronic treatments with these ligands can often produce diametrically opposite effects on damage outcome, probably resulting from adaptational changes in receptor number or properties. In some cases molecular approaches have identified the involvement of ERK and GSK-3beta pathways in the protection from damage. Much evidence argues for a role of adenosine receptors in neurological disease. Receptor densities are altered in patients with Alzheimer's disease, while many studies have demonstrated effects of adenosine and its antagonists on synaptic plasticity in vitro, or on learning adequacy in vivo. The combined effects of adenosine on neuronal viability and inflammatory processes have also led to considerations of their roles in Lesch-Nyhan syndrome, Creutzfeldt-Jakob disease, Huntington's disease and multiple sclerosis, as well as the brain damage associated with stroke. In addition to the potential pathological relevance of adenosine receptors, there are earnest attempts in progress to generate ligands that will target adenosine receptors as therapeutic agents to treat some of these disorders.
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Affiliation(s)
- Trevor W Stone
- Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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Apolloni S, Montilli C, Finocchi P, Amadio S. Membrane compartments and purinergic signalling: P2X receptors in neurodegenerative and neuroinflammatory events. FEBS J 2008; 276:354-64. [DOI: 10.1111/j.1742-4658.2008.06796.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Burnstock G. Purinergic signalling and disorders of the central nervous system. Nat Rev Drug Discov 2008; 7:575-90. [PMID: 18591979 DOI: 10.1038/nrd2605] [Citation(s) in RCA: 446] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Purines have key roles in neurotransmission and neuromodulation, with their effects being mediated by the purine and pyrimidine receptor subfamilies, P1, P2X and P2Y. Recently, purinergic mechanisms and specific receptor subtypes have been shown to be involved in various pathological conditions including brain trauma and ischaemia, neurodegenerative diseases involving neuroimmune and neuroinflammatory reactions, as well as in neuropsychiatric diseases, including depression and schizophrenia. This article reviews the role of purinergic signalling in CNS disorders, highlighting specific purinergic receptor subtypes, most notably A(2A), P2X(4) and P2X(7), that might be therapeutically targeted for the treatment of these conditions.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, Rowland Hill Street, London NW3 2PF, UK.
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Selective loss of P2Y2 nucleotide receptor immunoreactivity is associated with Alzheimer's disease neuropathology. J Neural Transm (Vienna) 2008; 115:1165-72. [PMID: 18506388 DOI: 10.1007/s00702-008-0067-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 05/05/2008] [Indexed: 10/22/2022]
Abstract
The uridine nucleotide-activated P2Y2, P2Y4 and P2Y6 receptors are widely expressed in the brain and are involved in many CNS processes, including those which malfunction in Alzheimer's disease (AD). However, the status of these receptors in the AD neocortex, as well as their putative roles in the pathogenesis of neuritic plaques and neurofibrillary tangles, remain unclear. In this study, we used immunoblotting to measure P2Y2, P2Y4 and P2Y6 receptors in two regions of the postmortem neocortex of neuropathologically assessed AD patients and aged controls. P2Y2 immunoreactivity was found to be selectively reduced in the AD parietal cortex, while P2Y4 and P2Y6 levels were unchanged. In contrast, all three receptors were preserved in the occipital cortex, which is known to be minimally affected by AD neuropathology. Furthermore, reductions in parietal P2Y2 immunoreactivity correlated both with neuropathologic scores and markers of synapse loss. These results provide a basis for considering P2Y2 receptor changes as a neurochemical substrate of AD, and point towards uridine nucleotide-activated P2Y receptors as novel targets for disease-modifying AD pharmacotherapeutic strategies.
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Wei W, Ryu JK, Choi HB, McLarnon JG. Expression and function of the P2X(7) receptor in rat C6 glioma cells. Cancer Lett 2007; 260:79-87. [PMID: 18039556 DOI: 10.1016/j.canlet.2007.10.025] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 10/03/2007] [Accepted: 10/17/2007] [Indexed: 11/15/2022]
Abstract
Our results demonstrate the first findings of expression and function of the purinergic P2X7 receptor (P2X7R) in rat C6 glioma cells. P2X7R mRNA and protein were present in unstimulated C6 cells and were up-regulated by cell exposure to the P2X7R agonist, 2',3'-(benzoyl-4-benzoyl)-ATP (BzATP). Activation of P2X7R in C6 in response to BzATP led to increased mobilization of intracellular calcium [Ca2+]i and formation of large pores. Chronic exposure of C6 cells to BzATP enhanced the expression of pro-inflammatory factors including MCP-1, IL-8 and VEGF. In a scratch-wound migration assay, the P2X7R was shown to regulate cell mobility. The overall results suggest that P2X7R activation in C6 is linked with increased pro-inflammatory factors and tumor cell migration.
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Affiliation(s)
- Wei Wei
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
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Klegeris A, Choi HB, McLarnon JG, McGeer PL. Functional ryanodine receptors are expressed by human microglia and THP-1 cells: Their possible involvement in modulation of neurotoxicity. J Neurosci Res 2007; 85:2207-15. [PMID: 17526017 DOI: 10.1002/jnr.21361] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ryanodine receptors (RyRs) are intracellular Ca(2+) channels that mediate the release of calcium from internal stores and therefore play an important role in Ca(2+) signaling and homeostasis. Three RyR isoforms have been described thus far, and various areas of brain are known to express each of them. It is well established that neurons can express different RyR isoforms, but it is not known whether microglial cells do so. In the present study we showed that cultured human microglia from both fetal and adult brain specimens express mRNA for RyR1 and RyR2, whereas RyR3 mRNA can be detected only in fetal microglial cells. Calcium spectrofluorometry showed that high levels of the RyR agonist 4-chloro-m-cresol (4-CmC, 1-5 mM) induced elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) in both types of cultured human microglial cells. This effect was attenuated by the RyR antagonist 1,1'-diheptyl-4,4'-bipyridinium dibromide (DHBP, 10 microM). Neurotoxicity of conditioned medium from human microglia and THP-1 monocytic cells stimulated with a combination of interferon-gamma (IFN-gamma) with either lipopolysaccharide (LPS) or alpha-synuclein was diminished by DHBP. It was also diminished by 4-CmC at concentrations approximately 100-fold lower than those used to stimulate intracellular Ca(2+) release. These data indicate that human microglial cells express functional RyRs and that selective RyR ligands exert antineurotoxic action on this cell type. Therefore, RyR ligands may represent a novel class of compounds that have utility in reducing microglial-mediated inflammation, which is believed to contribute to the pathogenesis of a number of neurodegenerative disorders including Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Andis Klegeris
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
This review is focused on purinergic neurotransmission, i.e., ATP released from nerves as a transmitter or cotransmitter to act as an extracellular signaling molecule on both pre- and postjunctional membranes at neuroeffector junctions and synapses, as well as acting as a trophic factor during development and regeneration. Emphasis is placed on the physiology and pathophysiology of ATP, but extracellular roles of its breakdown product, adenosine, are also considered because of their intimate interactions. The early history of the involvement of ATP in autonomic and skeletal neuromuscular transmission and in activities in the central nervous system and ganglia is reviewed. Brief background information is given about the identification of receptor subtypes for purines and pyrimidines and about ATP storage, release, and ectoenzymatic breakdown. Evidence that ATP is a cotransmitter in most, if not all, peripheral and central neurons is presented, as well as full accounts of neurotransmission and neuromodulation in autonomic and sensory ganglia and in the brain and spinal cord. There is coverage of neuron-glia interactions and of purinergic neuroeffector transmission to nonmuscular cells. To establish the primitive and widespread nature of purinergic neurotransmission, both the ontogeny and phylogeny of purinergic signaling are considered. Finally, the pathophysiology of purinergic neurotransmission in both peripheral and central nervous systems is reviewed, and speculations are made about future developments.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neurscience Centre, Royal Free and University College Medical School, London, UK.
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