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Qiu Q, Yang M, Gong D, Liang H, Chen T. Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders. Neural Regen Res 2025; 20:1258-1276. [PMID: 38845230 DOI: 10.4103/nrr.nrr-d-23-01766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/07/2024] [Indexed: 07/31/2024] Open
Abstract
The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channel-specific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood-brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.
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Affiliation(s)
- Qing Qiu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu Province, China
- Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu Province, China
| | - Mengting Yang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu Province, China
- Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu Province, China
| | - Danfeng Gong
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu Province, China
- Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu Province, China
| | - Haiying Liang
- Department of Pharmacy, Longyan First Affiliated Hospital of Fujian Medical University, Longyan, Fujian Province, China
| | - Tingting Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu Province, China
- Jiangsu Province Key Laboratory of Inflammation and Molecular Drug Target, Nantong, Jiangsu Province, China
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2
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Pramanik S, Devi M H, Chakrabarty S, Paylar B, Pradhan A, Thaker M, Ayyadhury S, Manavalan A, Olsson PE, Pramanik G, Heese K. Microglia signaling in health and disease - Implications in sex-specific brain development and plasticity. Neurosci Biobehav Rev 2024; 165:105834. [PMID: 39084583 DOI: 10.1016/j.neubiorev.2024.105834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 07/21/2024] [Accepted: 07/27/2024] [Indexed: 08/02/2024]
Abstract
Microglia, the intrinsic neuroimmune cells residing in the central nervous system (CNS), exert a pivotal influence on brain development, homeostasis, and functionality, encompassing critical roles during both aging and pathological states. Recent advancements in comprehending brain plasticity and functions have spotlighted conspicuous variances between male and female brains, notably in neurogenesis, neuronal myelination, axon fasciculation, and synaptogenesis. Nevertheless, the precise impact of microglia on sex-specific brain cell plasticity, sculpting diverse neural network architectures and circuits, remains largely unexplored. This article seeks to unravel the present understanding of microglial involvement in brain development, plasticity, and function, with a specific emphasis on microglial signaling in brain sex polymorphism. Commencing with an overview of microglia in the CNS and their associated signaling cascades, we subsequently probe recent revelations regarding molecular signaling by microglia in sex-dependent brain developmental plasticity, functions, and diseases. Notably, C-X3-C motif chemokine receptor 1 (CX3CR1), triggering receptors expressed on myeloid cells 2 (TREM2), calcium (Ca2+), and apolipoprotein E (APOE) emerge as molecular candidates significantly contributing to sex-dependent brain development and plasticity. In conclusion, we address burgeoning inquiries surrounding microglia's pivotal role in the functional diversity of developing and aging brains, contemplating their potential implications for gender-tailored therapeutic strategies in neurodegenerative diseases.
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Affiliation(s)
- Subrata Pramanik
- Jyoti and Bhupat Mehta School of Health Sciences and Technology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| | - Harini Devi M
- Jyoti and Bhupat Mehta School of Health Sciences and Technology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Saswata Chakrabarty
- Jyoti and Bhupat Mehta School of Health Sciences and Technology, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Berkay Paylar
- Biology, The Life Science Center, School of Science and Technology, Örebro University, Örebro 70182, Sweden
| | - Ajay Pradhan
- Biology, The Life Science Center, School of Science and Technology, Örebro University, Örebro 70182, Sweden
| | - Manisha Thaker
- Eurofins Lancaster Laboratories, Inc., 2425 New Holland Pike, Lancaster, PA 17601, USA
| | - Shamini Ayyadhury
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Arulmani Manavalan
- Department of Cariology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu 600077, India
| | - Per-Erik Olsson
- Biology, The Life Science Center, School of Science and Technology, Örebro University, Örebro 70182, Sweden
| | - Gopal Pramanik
- Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand 835215, India.
| | - Klaus Heese
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133791, the Republic of Korea.
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3
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Geloso MC, Zupo L, Corvino V. Crosstalk between peripheral inflammation and brain: Focus on the responses of microglia and astrocytes to peripheral challenge. Neurochem Int 2024; 180:105872. [PMID: 39362496 DOI: 10.1016/j.neuint.2024.105872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2024] [Revised: 09/18/2024] [Accepted: 09/30/2024] [Indexed: 10/05/2024]
Abstract
A growing body of evidence supports the link between peripheral inflammation and impairment of neurologic functions, including mood and cognitive abilities. The pathogenic event connecting peripheral inflammation and brain dysfunction is represented by neuroinflammation, a pathogenic phenomenon that provides an important contribution to neurodegeneration and cognitive decline also in Alzheimer's, Parkinson's, Huntington's diseases, as well as in Multiple Sclerosis. It is driven by resident brain immune cells, microglia and astrocytes, that acquire an activated phenotype in response to proinflammatory molecules moving from the periphery to the brain parenchyma. Although a huge progress has been made in clarifying cellular and molecular mechanisms bridging peripheral and central inflammation, a clear picture has not been achieved so far. Therefore, experimental models are of crucial relevance to clarify knowledge gaps in this regard. Many findings demonstrate that systemic inflammation induced by pathogen-associated molecular patterns, such as lipopolysaccharide (LPS), is able to trigger neuroinflammation. Therefore, LPS-administration is widely considered a useful tool to study this phenomenon. On this basis, the present review will focus on in vivo studies based on acute and subacute effects of systemic administration of LPS, with special attention on the state of art of microglia and astrocyte response to peripheral challenge.
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Affiliation(s)
- Maria Concetta Geloso
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy; Gemelli Science and Technology Park (GSTeP)-Organoids Research Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy.
| | - Luca Zupo
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
| | - Valentina Corvino
- Department of Neuroscience, Section of Human Anatomy, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168, Rome, Italy
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4
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Almalki WH, Almujri SS. Therapeutic approaches to microglial dysfunction in Alzheimer's disease: Enhancing phagocytosis and metabolic regulation. Pathol Res Pract 2024; 263:155614. [PMID: 39342887 DOI: 10.1016/j.prp.2024.155614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Revised: 09/04/2024] [Accepted: 09/24/2024] [Indexed: 10/01/2024]
Abstract
Microglia are essential in neurogenesis, synaptic pruning, and homeostasis. Nevertheless, aging, and cellular senescence may modify their role, causing them to shift from being shields to being players of neurodegeneration. In the aging brain, the population of microglia increases, followed by enhanced activity of genes related to neuroinflammation. This change increases their ability to cause inflammation, resulting in a long-lasting state of inflammation in the brain that harms the condition of neurons. In Alzheimer's Disease (AD), microglia are located inside amyloid plaques and exhibit an inflammatory phenotype characterized by a diminished ability to engulf and remove waste material, worsening the illness's advancement. Genetic polymorphisms in TREM2, APOE, and CD33 highlight the significant impact of microglial dysfunction in AD. This review examines therapeutic approaches that aim to address microglial dysfunction, such as enhancing the microglial capability to engulf and remove amyloid-β clumps and regulating microglial metabolism and mitochondrial activity. Microglial transplanting and reprogramming advancements show the potential to restore their ability to reduce inflammation. Although there has been notable advancement, there are still voids in our knowledge of microglial biology, including their relationships with other brain cells. Further studies should prioritize the improvement of human AD models, establish standardized methods for characterizing microglia, and explore how various factors influence microglial responses. It is essential to tackle these problems to create effective treatment plans that focus on reducing inflammation in the brain and protecting against damage in age-related neurodegenerative illnesses.
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Affiliation(s)
- Waleed Hassan Almalki
- Department of Pharmacology, College of Pharmacy, Umm Al-Qura University, Makkah, Saudi Arabia.
| | - Salem Salman Almujri
- Department of Pharmacology, College of Pharmacy, King Khalid University, Abha, Aseer 61421, Saudi Arabia
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5
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Poshtkohi A, Wade J, McDaid L, Liu J, Dallas ML, Bithell A. Mathematical Modeling of PI3K/Akt Pathway in Microglia. Neural Comput 2024; 36:645-676. [PMID: 38457763 DOI: 10.1162/neco_a_01643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/20/2023] [Indexed: 03/10/2024]
Abstract
The motility of microglia involves intracellular signaling pathways that are predominantly controlled by changes in cytosolic Ca2+ and activation of PI3K/Akt (phosphoinositide-3-kinase/protein kinase B). In this letter, we develop a novel biophysical model for cytosolic Ca2+ activation of the PI3K/Akt pathway in microglia where Ca2+ influx is mediated by both P2Y purinergic receptors (P2YR) and P2X purinergic receptors (P2XR). The model parameters are estimated by employing optimization techniques to fit the model to phosphorylated Akt (pAkt) experimental modeling/in vitro data. The integrated model supports the hypothesis that Ca2+ influx via P2YR and P2XR can explain the experimentally reported biphasic transient responses in measuring pAkt levels. Our predictions reveal new quantitative insights into P2Rs on how they regulate Ca2+ and Akt in terms of physiological interactions and transient responses. It is shown that the upregulation of P2X receptors through a repetitive application of agonist results in a continual increase in the baseline [Ca2+], which causes the biphasic response to become a monophasic response which prolongs elevated levels of pAkt.
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Affiliation(s)
- Alireza Poshtkohi
- School of Physics, Engineering and Computer Science, University of Hertfordshire, Hatfield, Hertfordshire, U.K.
| | - John Wade
- School of Computing, Engineering and Intelligent Systems, University of Ulster, Londonderry, U.K.
| | - Liam McDaid
- School of Computing, Engineering and Intelligent Systems, University of Ulster, Londonderry, U.K.
| | - Junxiu Liu
- School of Computing, Engineering and Intelligent Systems, University of Ulster, Londonderry, U.K.
| | - Mark L Dallas
- School of Pharmacy, University of Reading, Reading, U.K.
| | - Angela Bithell
- School of Pharmacy, University of Reading, Reading, U.K.
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6
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Qian H, Zhang HN, Gao T, Wang XS, Wang X, Yu MY, Li MK, Huang J. Upregulation of TRPC1 in microglia promotes neutrophil infiltration after ischemic stroke. Brain Res Bull 2024; 208:110894. [PMID: 38325758 DOI: 10.1016/j.brainresbull.2024.110894] [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: 12/06/2023] [Revised: 01/22/2024] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
Neutrophil infiltration has been linked to worse clinical outcomes after ischemic stroke. Microglia, a key type of immune-competent cell, engage in cross-talk with the infiltrating immune cells in the inflamed brain area, yet the molecular mechanisms involved remain largely unexplored. In this study, we investigated the mechanisms of how canonical transient receptor potential 1 (TRPC1) modulated neutrophil infiltration in male mouse cerebral ischemia and reperfusion injury (CIRI) models. Our findings revealed a notable upregulation of TRPC1 in microglia within both middle cerebral artery occlusion reperfusion (MCAO/R) and in vitro oxygen-glucose deprivation/regeneration (OGD/R) model. Conditional Trpc1 knockdown in microglia markedly reduced infarct volumes and alleviated neurological deficits. Microglia conditional Trpc1 knockdown mice displayed less neutrophil infiltration in peri-infarct area. Trpc1 knockdown microglia exhibited a reduced primed proinflammatory phenotype with less secretion of CC-Chemokines ligand (CCL) 5 and CCL2 after MCAO/R. Blocking CCL5/2 significantly mitigated neutrophil infiltration in microglia/neutrophil transwell co-culture system upon OGD/R condition. Trpc1 knockdown markedly reduced store-operated calcium entry and nuclear factor of activated T-cells c1 (NFATc1) level in OGD/R treated microglia. Overexpression of Nfatc1 reversed the CCL5/2 reducing effect of Trpc1 knockdown, which is mediated by small interfering RNA in BV2 cells upon OGD/R. Our data indicate that upregulation of TRPC1 in microglia stimulates the production of CCL5/2 through the Ca2+/NFATc1 pathway. Upregulated CCL5/2 leads to an increase in neutrophil infiltration into the brain, thereby aggravating reperfusion injury. Our results demonstrate the importance of TRPC1 in microglia-mediated neuroinflammation and suggest a potential means for reducing CIRI induced neurological injury.
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Affiliation(s)
- Hao Qian
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
| | - Hui-Nan Zhang
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Neurology, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China
| | - Tian Gao
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Neurology, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China
| | - Xin-Shang Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
| | - Xing Wang
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Neurology, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China
| | - Man-Yang Yu
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Neurology, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China
| | - Ming-Kai Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China.
| | - Jing Huang
- Health Management Center, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China; Department of Neurology, Second Affiliated Hospital, Fourth Military Medical University, Xi'an 710038, China.
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7
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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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Crockett A, Fuhrmann M, Garaschuk O, Davalos D. Progress in Structural and Functional In Vivo Imaging of Microglia and Their Application in Health and Disease. ADVANCES IN NEUROBIOLOGY 2024; 37:65-80. [PMID: 39207687 DOI: 10.1007/978-3-031-55529-9_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The first line of defense for the central nervous system (CNS) against injury or disease is provided by microglia. Microglia were long believed to stay in a dormant/resting state, reacting only to injury or disease. This view changed dramatically with the development of modern imaging techniques that allowed the study of microglial behavior in the intact brain over time, to reveal the dynamic nature of their responses. Over the past two decades, in vivo imaging using multiphoton microscopy has revealed numerous new functions of microglia in the developing, adult, aged, injured, and diseased CNS. As the most dynamic cells in the brain, microglia continuously contact all structures and cell types, such as glial and vascular cells, neuronal cell bodies, axons, dendrites, and dendritic spines, and are believed to play a central role in sculpting neuronal networks throughout life. Following trauma, or in neurodegenerative or neuroinflammatory diseases, microglial responses range from protective to harmful, underscoring the need to better understand their diverse roles and states in different pathological conditions. In this chapter, we introduce multiphoton microscopy and discuss recent advances in structural and functional imaging technologies that have expanded our toolbox to study microglial states and behaviors in new ways and depths. We also discuss relevant mouse models available for in vivo imaging studies of microglia and review how such studies are constantly refining our understanding of the multifaceted role of microglia in the healthy and diseased CNS.
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Affiliation(s)
- Alexis Crockett
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Martin Fuhrmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Dimitrios Davalos
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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Garaschuk O, Verkhratsky A. Calcium Signalling in Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:123-133. [PMID: 39207689 DOI: 10.1007/978-3-031-55529-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Intracellular Ca2+ signalling represents the substrate of microglial excitability. Spatially and temporally organised changes in the free cytoplasmic Ca2+ concentration ([Ca2+]i) are generated in response to physiological and pathological stimuli. Parameters of these intracellular Ca2+ signals are defined by Ca2+ signalling toolkits that may change with age or context therefore increasing adaptive capabilities of microglia. Main Ca2+ signalling pathways in microglial cells are associated with dynamic endoplasmic reticulum Ca2+ stores and with plasmalemmal Ca2+ entry mediated by several sets of Ca2+-permeable channels including transient receptor potential (TRP) channels, ORAI channels and P2X4/7 purinoceptors. Microglial Ca2+ dynamics is also linked to TREM2 signalling cascade, contributing to neuroprotection in neurodegenerative diseases. Microglial Ca2+ signals act as reliable and precise sensors of brain dyshomeostasis and pathological insults.
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Affiliation(s)
- Olga Garaschuk
- Institute of Physiology, Department Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Department of Neurosciences, University of the Basque Country, Leioa, Spain.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Pan K, Garaschuk O. The role of intracellular calcium-store-mediated calcium signals in in vivo sensor and effector functions of microglia. J Physiol 2023; 601:4203-4215. [PMID: 35315518 DOI: 10.1113/jp279521] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/09/2022] [Indexed: 11/08/2022] Open
Abstract
Under physiological conditions microglia, the immune sentinels of the brain, constantly monitor their microenvironment. In the case of danger, damage or cell/tissue dyshomeostasis, they react with changes in process motility, polarization, directed process movement, morphology and gene expression profile; release pro- and anti-inflammatory mediators; proliferate; and clean brain parenchyma by means of phagocytosis. Based on recent transcriptomic and in vivo Ca2+ imaging data, we argue that the local cell/tissue dyshomeostasis is sensed by microglia via intracellular Ca2+ signals, many of which are mediated by Ca2+ release from the intracellular Ca2+ stores. These signals encode the strength, duration and spatiotemporal pattern of the stimulus and, at the same time, relay this information further to trigger the respective Ca2+ -dependent effector pathways. We also point to the fact that microglial Ca2+ signalling is sexually dimorphic and undergoes profound changes across the organism's lifespan. Interestingly, the first changes in microglial Ca2+ signalling are visible already in 9- to 11-month-old mice, roughly corresponding to 40-year-old humans.
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Affiliation(s)
- Kuang Pan
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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Shin YK, Seol GH. Effects of linalyl acetate on oxidative stress, inflammation and endothelial dysfunction: can linalyl acetate prevent mild cognitive impairment? Front Pharmacol 2023; 14:1233977. [PMID: 37576815 PMCID: PMC10416234 DOI: 10.3389/fphar.2023.1233977] [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: 06/03/2023] [Accepted: 07/21/2023] [Indexed: 08/15/2023] Open
Abstract
Mild cognitive impairment (MCI) is a major public health challenge with an increasing prevalence. Although the mechanisms underlying the development of MCI remain unclear, MCI has been reported to be associated with oxidative stress, inflammatory responses, and endothelial dysfunction, suggesting that agents that reduce these factors may be key to preventing MCI. Currently, no agents have been approved for the treatment of MCI, with the efficacy of commonly prescribed cholinesterase inhibitors remaining unclear. Relatively safe natural products that can prevent the development of MCI are of great interest. Linalyl acetate (LA), the major component of clary sage and lavender essential oils, has been shown to have a variety of pharmacological effects, including anti-hypertensive, anti-diabetic, neuroprotective, anti-inflammatory, and antioxidant properties, which may have the potential for the prevention of MCI. The present review briefly summarizes the pathogenesis of MCI related to oxidative stress, inflammatory responses, and endothelial dysfunction as well as the benefits of LA against these MCI-associated factors. The PubMed and Google Scholar databases were used to search the relevant literature. Further clinical research may lead to the development of new strategies for preventing MCI, particularly in high-risk populations with oxidative stress, inflammatory responses, and endothelial dysfunction (e.g., patients with hypertension and/or diabetes mellitus).
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Affiliation(s)
- You Kyoung Shin
- Department of Basic Nursing Science, College of Nursing, Korea University, Seoul, Republic of Korea
| | - Geun Hee Seol
- Department of Basic Nursing Science, College of Nursing, Korea University, Seoul, Republic of Korea
- BK21 FOUR Program of Transdisciplinary Major in Learning Health Systems, Graduate School, Korea University, Seoul, Republic of Korea
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12
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Wickline JL, Smith S, Shin R, Odfalk K, Sanchez J, Javors M, Ginsburg B, Hopp SC. L-type calcium channel antagonist isradipine age-dependently decreases plaque associated dystrophic neurites in 5XFAD mouse model. Neuropharmacology 2023; 227:109454. [PMID: 36740015 PMCID: PMC9987839 DOI: 10.1016/j.neuropharm.2023.109454] [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: 11/15/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
Epidemiological studies suggest that L-type calcium channel (LTCC) antagonists may reduce the incidence of age-associated neurodegenerative diseases including Alzheimer's disease (AD). However, the neuroprotective mechanism of LTCC antagonists is unknown. Amyloid-β (Aβ) pathology disrupts intracellular calcium signaling, which regulates lysosomes and microglial responses. Neurons near Aβ plaques develop dystrophic neurites, which are abnormal swellings that accumulate lysosomes. Further, microglia accumulate around Aβ plaques and secrete inflammatory cytokines. We hypothesized that antagonism of LTCCs with isradipine would reduce Aβ plaque-associated dystrophic neurites and inflammatory microglia in the 5XFAD mouse model by restoring normal intracellular calcium regulation. To test this hypothesis, we treated 6- and 9-month-old 5XFAD mice with isradipine and tested behavior, examined Aβ plaques, microglia, and dystrophic neurites. We found that isradipine treatment age-dependently reduces dystrophic neurites and leads to trending decreases in Aβ but does not modulate plaque associated microglia regardless of age. Our findings provide insight into how antagonizing LTCCs alters specific cell types in the Aβ plaque environment, providing valuable information for potential treatment targets in future AD studies.
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Affiliation(s)
- Jessica L Wickline
- 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
| | - Sabrina Smith
- 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
| | - Riley Shin
- Department of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
| | - Kristian Odfalk
- 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
| | - Jesse Sanchez
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Martin Javors
- Department of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, TX, USA; Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Brett Ginsburg
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - 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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Du T, Zhou X, Zhang RDY, Du XF. Roles of Ca2+ activity in injury-induced migration of microglia in zebrafish in vivo. Biochem Biophys Rep 2022; 32:101340. [PMID: 36120493 PMCID: PMC9471311 DOI: 10.1016/j.bbrep.2022.101340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/21/2022] [Accepted: 08/30/2022] [Indexed: 10/28/2022] Open
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14
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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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15
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Kim J, Jeon SG, Jeong HR, Park H, Kim JI, Hoe HS. L-Type Ca 2+ Channel Inhibition Rescues the LPS-Induced Neuroinflammatory Response and Impairments in Spatial Memory and Dendritic Spine Formation. Int J Mol Sci 2022; 23:13606. [PMID: 36362394 PMCID: PMC9655622 DOI: 10.3390/ijms232113606] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/26/2022] [Accepted: 11/03/2022] [Indexed: 08/11/2023] Open
Abstract
Ca2+ signaling is implicated in the transition between microglial surveillance and activation. Several L-type Ca2+ channel blockers (CCBs) have been shown to ameliorate neuroinflammation by modulating microglial activity. In this study, we examined the effects of the L-type CCB felodipine on LPS-mediated proinflammatory responses. We found that felodipine treatment significantly diminished LPS-evoked proinflammatory cytokine levels in BV2 microglial cells in an L-type Ca2+ channel-dependent manner. In addition, felodipine leads to the inhibition of TLR4/AKT/STAT3 signaling in BV2 microglial cells. We further examined the effects of felodipine on LPS-stimulated neuroinflammation in vivo and found that daily administration (3 or 7 days, i.p.) significantly reduced LPS-mediated gliosis and COX-2 and IL-1β levels in C57BL/6 (wild-type) mice. Moreover, felodipine administration significantly reduced chronic neuroinflammation-induced spatial memory impairment, dendritic spine number, and microgliosis in C57BL/6 mice. Taken together, our results suggest that the L-type CCB felodipine could be repurposed for the treatment of neuroinflammation/cognitive function-associated diseases.
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Affiliation(s)
- Jieun Kim
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu 41062, Korea
| | - Seong Gak Jeon
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu 41062, Korea
| | - Ha-Ram Jeong
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu 41062, Korea
| | - HyunHee Park
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu 41062, Korea
| | - Jae-Ick Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), 61, Cheomdan-ro, Dong-gu, Daegu 41062, Korea
- Department of Brain and Cognitive Science, Daegu Gyeongbuk Institute of Science & Technology (DGIST), 333, Techno Jungang-Daero, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Korea
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16
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Wendimu MY, Hooks SB. Microglia Phenotypes in Aging and Neurodegenerative Diseases. Cells 2022; 11:2091. [PMID: 35805174 PMCID: PMC9266143 DOI: 10.3390/cells11132091] [Citation(s) in RCA: 91] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation is a hallmark of many neurodegenerative diseases (NDs) and plays a fundamental role in mediating the onset and progression of disease. Microglia, which function as first-line immune guardians of the central nervous system (CNS), are the central drivers of neuroinflammation. Numerous human postmortem studies and in vivo imaging analyses have shown chronically activated microglia in patients with various acute and chronic neuropathological diseases. While microglial activation is a common feature of many NDs, the exact role of microglia in various pathological states is complex and often contradictory. However, there is a consensus that microglia play a biphasic role in pathological conditions, with detrimental and protective phenotypes, and the overall response of microglia and the activation of different phenotypes depends on the nature and duration of the inflammatory insult, as well as the stage of disease development. This review provides a comprehensive overview of current research on the various microglia phenotypes and inflammatory responses in health, aging, and NDs, with a special emphasis on the heterogeneous phenotypic response of microglia in acute and chronic diseases such as hemorrhagic stroke (HS), Alzheimer's disease (AD), and Parkinson's disease (PD). The primary focus is translational research in preclinical animal models and bulk/single-cell transcriptome studies in human postmortem samples. Additionally, this review covers key microglial receptors and signaling pathways that are potential therapeutic targets to regulate microglial inflammatory responses during aging and in NDs. Additionally, age-, sex-, and species-specific microglial differences will be briefly reviewed.
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Affiliation(s)
| | - Shelley B. Hooks
- Hooks Lab, Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA;
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17
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Rieder P, Gobbo D, Stopper G, Welle A, Damo E, Kirchhoff F, Scheller A. Astrocytes and Microglia Exhibit Cell-Specific Ca2+ Signaling Dynamics in the Murine Spinal Cord. Front Mol Neurosci 2022; 15:840948. [PMID: 35431801 PMCID: PMC9006623 DOI: 10.3389/fnmol.2022.840948] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/22/2022] [Indexed: 12/31/2022] Open
Abstract
The spinal cord is the main pathway connecting brain and peripheral nervous system. Its functionality relies on the orchestrated activity of both neurons and glial cells. To date, most advancement in understanding the spinal cord inner mechanisms has been made either by in vivo exposure of its dorsal surface through laminectomy or by acute ex vivo slice preparation, likely affecting spinal cord physiology in virtue of the necessary extensive manipulation of the spinal cord tissue. This is especially true of cells immediately responding to alterations of the surrounding environment, such as microglia and astrocytes, reacting within seconds or minutes and for up to several days after the original insult. Ca2+ signaling is considered one of the most immediate, versatile, and yet elusive cellular responses of glia. Here, we induced the cell-specific expression of the genetically encoded Ca2+ indicator GCaMP3 to evaluate spontaneous intracellular Ca2+ signaling in astrocytes and microglia. Ca2+ signals were then characterized in acute ex vivo (both gray and white matter) as well as in chronic in vivo (white matter) preparations using MSparkles, a MATLAB-based software for automatic detection and analysis of fluorescence events. As a result, we were able to segregate distinct astroglial and microglial Ca2+ signaling patterns along with method-specific Ca2+ signaling alterations, which must be taken into consideration in the reliable evaluation of any result obtained in physiological as well as pathological conditions. Our study revealed a high degree of Ca2+ signaling diversity in glial cells of the murine spinal cord, thus adding to the current knowledge of the astonishing glial heterogeneity and cell-specific Ca2+ dynamics in non-neuronal networks.
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Affiliation(s)
- Phillip Rieder
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Davide Gobbo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gebhard Stopper
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anna Welle
- Department of Genetics and Epigenetics, University of Saarland, Saarbrücken, Germany
| | - Elisa Damo
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
- Institute of Pharmacology, Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Frank Kirchhoff
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Department of Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
- *Correspondence: Anja Scheller,
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18
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Logiacco F, Xia P, Georgiev SV, Franconi C, Chang YJ, Ugursu B, Sporbert A, Kühn R, Kettenmann H, Semtner M. Microglia sense neuronal activity via GABA in the early postnatal hippocampus. Cell Rep 2021; 37:110128. [PMID: 34965412 DOI: 10.1016/j.celrep.2021.110128] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 09/14/2021] [Accepted: 11/22/2021] [Indexed: 01/05/2023] Open
Abstract
Microglia, the resident macrophages in the central nervous system, express receptors for classical neurotransmitters, such as γ-aminobutyric acid (GABA) and glutamate, suggesting that they sense synaptic activity. To detect microglial Ca2+ responses to neuronal activity, we generate transgenic mouse lines expressing the fluorescent Ca2+ indicator GCaMP6m, specifically in microglia and demonstrate that electrical stimulation of the Schaffer collateral pathway results in microglial Ca2+ responses in early postnatal but not adult hippocampus. Preceding the microglial responses, we also observe similar Ca2+ responses in astrocytes, and both are sensitive to tetrodotoxin. Blocking astrocytic glutamate uptake or GABA transport abolishes stimulation-induced microglial responses as well as antagonizing the microglial GABAB receptor. Our data, therefore, suggest that the neuronal activity-induced glutamate uptake and the release of GABA by astrocytes trigger the activation of GABAB receptors in microglia. This neuron, astrocyte, and microglia communication pathway might modulate microglial activity in developing neuronal networks.
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Affiliation(s)
- Francesca Logiacco
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany; Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 12169 Berlin, Germany
| | - Pengfei Xia
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Svilen Veselinov Georgiev
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Celeste Franconi
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Yi-Jen Chang
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Bilge Ugursu
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany; Experimental Ophthalmology, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Anje Sporbert
- Advanced Light Microscopy, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Ralf Kühn
- Transgenic Core Facility, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany; Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.
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19
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Cocozza G, Garofalo S, Capitani R, D’Alessandro G, Limatola C. Microglial Potassium Channels: From Homeostasis to Neurodegeneration. Biomolecules 2021; 11:1774. [PMID: 34944418 PMCID: PMC8698630 DOI: 10.3390/biom11121774] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/21/2022] Open
Abstract
The growing interest in the role of microglia in the progression of many neurodegenerative diseases is developing in an ever-expedited manner, in part thanks to emergent new tools for studying the morphological and functional features of the CNS. The discovery of specific biomarkers of the microglia phenotype could find application in a wide range of human diseases, and creates opportunities for the discovery and development of tailored therapeutic interventions. Among these, recent studies highlight the pivotal role of the potassium channels in regulating microglial functions in physiological and pathological conditions such as Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis. In this review, we summarize the current knowledge of the involvement of the microglial potassium channels in several neurodegenerative diseases and their role as modulators of microglial homeostasis and dysfunction in CNS disorders.
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Affiliation(s)
- Germana Cocozza
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
| | - Stefano Garofalo
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Riccardo Capitani
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Giuseppina D’Alessandro
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; (S.G.); (R.C.)
| | - Cristina Limatola
- Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy; (G.C.); (G.D.)
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University of Rome, 00185 Rome, Italy
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20
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Poshtkohi A, Wade J, McDaid L, Liu J, Dallas M, Bithell A. Mathematical modelling of human P2X-mediated plasma membrane electrophysiology and calcium dynamics in microglia. PLoS Comput Biol 2021; 17:e1009520. [PMID: 34723961 PMCID: PMC8584768 DOI: 10.1371/journal.pcbi.1009520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 11/11/2021] [Accepted: 10/02/2021] [Indexed: 01/14/2023] Open
Abstract
Regulation of cytosolic calcium (Ca2+) dynamics is fundamental to microglial function. Temporal and spatial Ca2+ fluxes are induced from a complicated signal transduction pathway linked to brain ionic homeostasis. In this paper, we develop a novel biophysical model of Ca2+ and sodium (Na+) dynamics in human microglia and evaluate the contribution of purinergic receptors (P2XRs) to both intracellular Ca2+ and Na+ levels in response to agonist/ATP binding. This is the first comprehensive model that integrates P2XRs to predict intricate Ca2+ and Na+ transient responses in microglia. Specifically, a novel compact biophysical model is proposed for the capture of whole-cell patch-clamp currents associated with P2X4 and P2X7 receptors, which is composed of only four state variables. The entire model shows that intricate intracellular ion dynamics arise from the coupled interaction between P2X4 and P2X7 receptors, the Na+/Ca2+ exchanger (NCX), Ca2+ extrusion by the plasma membrane Ca2+ ATPase (PMCA), and Ca2+ and Na+ leak channels. Both P2XRs are modelled as two separate adenosine triphosphate (ATP) gated Ca2+ and Na+ conductance channels, where the stoichiometry is the removal of one Ca2+ for the hydrolysis of one ATP molecule. Two unique sets of model parameters were determined using an evolutionary algorithm to optimise fitting to experimental data for each of the receptors. This allows the proposed model to capture both human P2X7 and P2X4 data (hP2X7 and hP2X4). The model architecture enables a high degree of simplicity, accuracy and predictability of Ca2+ and Na+ dynamics thus providing quantitative insights into different behaviours of intracellular Na+ and Ca2+ which will guide future experimental research. Understanding the interactions between these receptors and other membrane-bound transporters provides a step forward in resolving the qualitative link between purinergic receptors and microglial physiology and their contribution to brain pathology. Mathematical modelling and computer simulation are powerful tools by which we can analyse complex biological systems, particularly, neural phenomena involved in brain dysfunction. In this research, we develop a theoretical foundation for studying P2X-mediated calcium and sodium signalling in human microglial cells. Microglia, which are brain-resident macrophages, restructure their intracellular actin cytoskeleton to enable motility; this restructuring requires a complex molecular cascade involving a set of ionic channels, membrane-coupled receptors and cytosolic components. Recent studies highlight the importance for increasing our understanding of microglia physiology, since their functions play critical roles in both normal physiological and pathological dynamics of the brain. There is a need to develop reliable human cellular models to investigate the biology of microglia aimed at understanding the influence of purinergic signalling in brain dysfunction to provide novel drug discovery targets. In this work, a detailed mathematical model is built for the dynamics of human P2XRs in microglia. Subsequently, experimental whole-cell currents are used to derive P2X-mediated electrophysiology of human microglia (i.e. sodium and calcium dynamics, and membrane potential). Our predictions reveal new quantitative insights into P2XRs on how they regulate ionic concentrations in terms of physiological interactions and transient responses.
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Affiliation(s)
- Alireza Poshtkohi
- School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom
- * E-mail:
| | - John Wade
- School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom
| | - Liam McDaid
- School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom
| | - Junxiu Liu
- School of Computing, Engineering and Intelligent Systems, Ulster University, Londonderry, United Kingdom
| | - Mark Dallas
- School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Angela Bithell
- School of Pharmacy, University of Reading, Reading, United Kingdom
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21
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Lushchak VI, Duszenko M, Gospodaryov DV, Garaschuk O. Oxidative Stress and Energy Metabolism in the Brain: Midlife as a Turning Point. Antioxidants (Basel) 2021; 10:1715. [PMID: 34829586 PMCID: PMC8614699 DOI: 10.3390/antiox10111715] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/23/2021] [Accepted: 10/25/2021] [Indexed: 01/10/2023] Open
Abstract
Neural tissue is one of the main oxygen consumers in the mammalian body, and a plentitude of metabolic as well as signaling processes within the brain is accompanied by the generation of reactive oxygen (ROS) and nitrogen (RNS) species. Besides the important signaling roles, both ROS and RNS can damage/modify the self-derived cellular components thus promoting neuroinflammation and oxidative stress. While previously, the latter processes were thought to progress linearly with age, newer data point to midlife as a critical turning point. Here, we describe (i) the main pathways leading to ROS/RNS generation within the brain, (ii) the main defense systems for their neutralization and (iii) summarize the recent literature about considerable changes in the energy/ROS homeostasis as well as activation state of the brain's immune system at midlife. Finally, we discuss the role of calorie restriction as a readily available and cost-efficient antiaging and antioxidant lifestyle intervention.
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Affiliation(s)
- Volodymyr I. Lushchak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., 76018 Ivano-Frankivsk, Ukraine; (V.I.L.); (D.V.G.)
- Department of Medical Biochemistry, I. Horbachevsky Ternopil National Medical University, 46002 Ternopil, Ukraine
- Research and Development University, 13a Shota Rustaveli Str., 76018 Ivano-Frankivsk, Ukraine
| | - Michael Duszenko
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, 72074 Tübingen, Germany;
| | - Dmytro V. Gospodaryov
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., 76018 Ivano-Frankivsk, Ukraine; (V.I.L.); (D.V.G.)
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, 72074 Tübingen, Germany;
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22
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Synapse development is regulated by microglial THIK-1 K + channels. Proc Natl Acad Sci U S A 2021; 118:2106294118. [PMID: 34642249 PMCID: PMC8545484 DOI: 10.1073/pnas.2106294118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2021] [Indexed: 12/17/2022] Open
Abstract
Microglia are the brain’s resident immune cells, surveying the brain with motile processes, which can remove pathogens but also prune unnecessary junctions between the neurons (synapses). A potassium channel, THIK-1, in the microglial membrane allows efflux of potassium from these cells and thereby regulates their membrane voltage as well as their process motility and release of inflammatory mediators. Here, using THIK-1–blocking drugs and THIK-1–deficient mice, we demonstrate that THIK-1 controls removal of synaptic material by microglia, which reduces the number of functional synapses in the developing brain.
Microglia are the resident immune cells of the central nervous system. They constantly survey the brain parenchyma for redundant synapses, debris, or dying cells, which they remove through phagocytosis. Microglial ramification, motility, and cytokine release are regulated by tonically active THIK-1 K+ channels on the microglial plasma membrane. Here, we examined whether these channels also play a role in phagocytosis. Using pharmacological blockers and THIK-1 knockout (KO) mice, we found that a lack of THIK-1 activity approximately halved both microglial phagocytosis and marker levels for the lysosomes that degrade phagocytically removed material. These changes may reflect a decrease of intracellular [Ca2+]i activity, which was observed when THIK-1 activity was reduced, since buffering [Ca2+]i reduced phagocytosis. Less phagocytosis is expected to result in impaired pruning of synapses. In the hippocampus, mice lacking THIK-1 expression had an increased number of anatomically and electrophysiologically defined glutamatergic synapses during development. This resulted from an increased number of presynaptic terminals, caused by impaired removal by THIK-1 KO microglia. The dependence of synapse number on THIK-1 K+ channels, which control microglial surveillance and phagocytic ability, implies that changes in the THIK-1 expression level in disease states may contribute to altering neural circuit function.
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23
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Effects of Metformin on Spontaneous Ca 2+ Signals in Cultured Microglia Cells under Normoxic and Hypoxic Conditions. Int J Mol Sci 2021; 22:ijms22179493. [PMID: 34502402 PMCID: PMC8430509 DOI: 10.3390/ijms22179493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/20/2021] [Accepted: 08/28/2021] [Indexed: 12/12/2022] Open
Abstract
Microglial functioning depends on Ca2+ signaling. By using Ca2+ sensitive fluorescence dye, we studied how inhibition of mitochondrial respiration changed spontaneous Ca2+ signals in soma of microglial cells from 5-7-day-old rats grown under normoxic and mild-hypoxic conditions. In microglia under normoxic conditions, metformin or rotenone elevated the rate and the amplitude of Ca2+ signals 10-15 min after drug application. Addition of cyclosporin A, a blocker of mitochondrial permeability transition pore (mPTP), antioxidant trolox, or inositol 1,4,5-trisphosphate receptor (IP3R) blocker caffeine in the presence of rotenone reduced the elevated rate and the amplitude of the signals implying sensitivity to reactive oxygen species (ROS), and involvement of mitochondrial mPTP together with IP3R. Microglial cells exposed to mild hypoxic conditions for 24 h showed elevated rate and increased amplitude of Ca2+ signals. Application of metformin or rotenone but not phenformin before mild hypoxia reduced this elevated rate. Thus, metformin and rotenone had the opposing fast action in normoxia after 10-15 min and the slow action during 24 h mild-hypoxia implying activation of different signaling pathways. The slow action of metformin through inhibition of complex I could stabilize Ca2+ homeostasis after mild hypoxia and could be important for reduction of ischemia-induced microglial activation.
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Zhang Y, Cui D. Evolving Models and Tools for Microglial Studies in the Central Nervous System. Neurosci Bull 2021; 37:1218-1233. [PMID: 34106404 PMCID: PMC8353053 DOI: 10.1007/s12264-021-00706-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/27/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia play multiple roles in such processes as brain development, homeostasis, and pathology. Due to their diverse mechanisms of functions, the complex sub-classifications, and the large differences between different species, especially compared with humans, very different or even opposite conclusions can be drawn from studies with different research models. The choice of appropriate research models and the associated tools are thus key ingredients of studies on microglia. Mice are the most commonly used animal models. In this review, we summarize in vitro and in vivo models of mouse and human-derived microglial research models, including microglial cell lines, primary microglia, induced microglia-like cells, transgenic mice, human-mouse chimeric models, and microglial replacement models. We also summarize recent developments in novel single-cell and in vivo imaging technologies. We hope our review can serve as an efficient reference for the future study of microglia.
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Affiliation(s)
- Yang Zhang
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030, China
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai, 201108, China
| | - Donghong Cui
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030, China.
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai, 201108, China.
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Xia P, Logiacco F, Huang Y, Kettenmann H, Semtner M. Histamine triggers microglial responses indirectly via astrocytes and purinergic signaling. Glia 2021; 69:2291-2304. [PMID: 34080730 DOI: 10.1002/glia.24039] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
Histamine is a monoaminergic neurotransmitter which is released within the entire brain from ascending axons originating in the tuberomammillary nucleus in a sleep state-dependent fashion. Besides the modulation of neuronal firing patterns, brain histamine levels are also thought to modulate functions of glial cells. Microglia are the innate immune cells and professional phagocytes of the central nervous system, and histamine was previously shown to have multiple effects on microglial functions in health and disease. Isolated microglia respond only to agonists of the Hrh2 subtype of histamine receptors (Hrh), and the expression of that isoform is confirmed by a metadata analysis of microglia transcriptomes. When we studied the effect of the histamine receptor isoforms in cortical and thalamic microglia by in situ live cell Ca2+ imaging using a novel, microglia-specific indicator mouse line, microglial cells respond to external histamine application mainly in a Hrh1-, and to a lower extent also in a Hrh2-dependent manner. The Hrh1 response was sensitive to blockers of purinergic P2ry12 receptors, and since Hrh1 expression was predominantly found in astrocytes, we suggest that the Hrh1 response in microglia is mediated by astrocyte ATP release and activation of P2ry12 receptors in microglia. Histamine also stimulates microglial phagocytic activity via Hrh1- and P2ry12-mediated signaling. Taken together, we provide evidence that histamine acts indirectly on microglial Ca2+ levels and phagocytic activity via astrocyte histamine receptor-controlled purinergic signaling.
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Affiliation(s)
- Pengfei Xia
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Charité-Universitätsmedizin, Berlin, Germany
| | - Francesca Logiacco
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Yimin Huang
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Charité-Universitätsmedizin, Berlin, Germany
| | - Helmut Kettenmann
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.,Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Changing Functional Signatures of Microglia along the Axis of Brain Aging. Int J Mol Sci 2021; 22:ijms22031091. [PMID: 33499206 PMCID: PMC7865559 DOI: 10.3390/ijms22031091] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/19/2022] Open
Abstract
Microglia, the innate immune cells of the brain, are commonly perceived as resident macrophages of the central nervous system (CNS). This definition, however, requires further specification, as under healthy homeostatic conditions, neither morphological nor functional properties of microglia mirror those of classical macrophages. Indeed, microglia adapt exceptionally well to their microenvironment, becoming a legitimate member of the cellular brain architecture. The ramified or surveillant microglia in the young adult brain are characterized by specific morphology (small cell body and long, thin motile processes) and physiology (a unique pattern of Ca2+ signaling, responsiveness to various neurotransmitters and hormones, in addition to classic “immune” stimuli). Their numerous physiological functions far exceed and complement their immune capabilities. As the brain ages, the respective changes in the microglial microenvironment impact the functional properties of microglia, triggering further rounds of adaptation. In this review, we discuss the recent data showing how functional properties of microglia adapt to age-related changes in brain parenchyma in a sex-specific manner, with a specific focus on early changes occurring at middle age as well as some strategies counteracting the aging of microglia.
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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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Morales-Ropero JM, Arroyo-Urea S, Neubrand VE, Martín-Oliva D, Marín-Teva JL, Cuadros MA, Vangheluwe P, Navascués J, Mata AM, Sepúlveda MR. The endoplasmic reticulum Ca 2+ -ATPase SERCA2b is upregulated in activated microglia and its inhibition causes opposite effects on migration and phagocytosis. Glia 2020; 69:842-857. [PMID: 33105046 DOI: 10.1002/glia.23931] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
Activation of microglia is an early immune response to damage in the brain. Although a key role for Ca2+ as trigger of microglial activation has been considered, little is known about the molecular scenario for regulating Ca2+ homeostasis in these cells. Taking into account the importance of the endoplasmic reticulum as a cellular Ca2+ store, the sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA2b) is an interesting target to modulate intracellular Ca2+ dynamics. We found upregulation of SERCA2b in activated microglia of human brain with Alzheimer's disease and we further studied the participation of SERCA2b in microglial functions by using the BV2 murine microglial cell line and primary microglia isolated from mouse brain. To trigger microglia activation, we used the bacterial lipopolysaccharide (LPS), which is known to induce an increase of cytosolic Ca2+ . Our results showed an upregulated expression of SERCA2b in LPS-induced activated microglia likely associated to an attempt to restore the increased cytosolic Ca2+ concentration. We analyzed SERCA2b contribution in microglial migration by using the specific SERCA inhibitor thapsigargin in scratch assays. Microglial migration was strongly stimulated with thapsigargin, even more than with LPS-induction, but delayed in time. However, phagocytic capacity of microglia was blocked in the presence of the SERCA inhibitor, indicating the importance of a tight control of cytosolic Ca2+ in these processes. All together, these results provide for the first time compelling evidence for SERCA2b as a major player regulating microglial functions, affecting migration and phagocytosis in an opposite manner.
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Affiliation(s)
- Juan M Morales-Ropero
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Sandra Arroyo-Urea
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Veronika E Neubrand
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - David Martín-Oliva
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - José L Marín-Teva
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Miguel A Cuadros
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Julio Navascués
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
| | - Ana M Mata
- Department of Biochemistry and Molecular Biology and Genetics, Faculty of Sciences, University of Extremadura, Badajoz, Spain
| | - M Rosario Sepúlveda
- Department of Cell Biology, Faculty of Sciences, University of Granada, Granada, Spain
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Gamage R, Wagnon I, Rossetti I, Childs R, Niedermayer G, Chesworth R, Gyengesi E. Cholinergic Modulation of Glial Function During Aging and Chronic Neuroinflammation. Front Cell Neurosci 2020; 14:577912. [PMID: 33192323 PMCID: PMC7594524 DOI: 10.3389/fncel.2020.577912] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Aging is a complex biological process that increases the risk of age-related cognitive degenerative diseases such as dementia, including Alzheimer’s disease (AD), Lewy Body Dementia (LBD), and mild cognitive impairment (MCI). Even non-pathological aging of the brain can involve chronic oxidative and inflammatory stress, which disrupts the communication and balance between the brain and the immune system. There has been an increasingly strong connection found between chronic neuroinflammation and impaired memory, especially in AD. While microglia and astrocytes, the resident immune cells of the central nervous system (CNS), exerting beneficial effects during the acute inflammatory phase, during chronic neuroinflammation they can become more detrimental. Central cholinergic circuits are involved in maintaining normal cognitive function and regulating signaling within the entire cerebral cortex. While neuronal-glial cholinergic signaling is anti-inflammatory and anti-oxidative, central cholinergic neuronal degeneration is implicated in impaired learning, memory sleep regulation, and attention. Although there is evidence of cholinergic involvement in memory, fewer studies have linked the cholinergic anti-inflammatory and anti-oxidant pathways to memory processes during development, normal aging, and disease states. This review will summarize the current knowledge of cholinergic effects on microglia and astroglia, and their role in both anti-inflammatory and anti-oxidant mechanisms, concerning normal aging and chronic neuroinflammation. We provided details on how stimulation of α7 nicotinic acetylcholine (α7nACh) receptors can be neuroprotective by increasing amyloid-β phagocytosis, decreasing inflammation and reducing oxidative stress by promoting the nuclear factor erythroid 2-related factor 2 (Nrf2) pathways and decreasing the release of pro-inflammatory cytokines. There is also evidence for astroglial α7nACh receptor stimulation mediating anti-inflammatory and antioxidant effects by inhibiting the nuclear factor-κB (NF-κB) pathway and activating the Nrf2 pathway respectively. We conclude that targeting cholinergic glial interactions between neurons and glial cells via α7nACh receptors could regulate neuroinflammation and oxidative stress, relevant to the treatment of several neurodegenerative diseases.
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Affiliation(s)
- Rashmi Gamage
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ingrid Wagnon
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ilaria Rossetti
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ryan Childs
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Garry Niedermayer
- School of Science, Western Sydney University, Penrith, NSW, Australia
| | - Rose Chesworth
- School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Erika Gyengesi
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
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31
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de Melo Reis RA, Freitas HR, de Mello FG. Cell Calcium Imaging as a Reliable Method to Study Neuron-Glial Circuits. Front Neurosci 2020; 14:569361. [PMID: 33122991 PMCID: PMC7566175 DOI: 10.3389/fnins.2020.569361] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022] Open
Abstract
Complex dynamic cellular networks have been studied in physiological and pathological processes under the light of single-cell calcium imaging (SCCI), a method that correlates functional data based on calcium shifts operated by different intracellular and extracellular mechanisms integrated with their cell phenotypes. From the classic synaptic structure to tripartite astrocytic model or the recent quadripartite microglia added ensemble, as well as other physiological tissues, it is possible to follow how cells signal spatiotemporally to cellular patterns. This methodology has been used broadly due to the universal properties of calcium as a second messenger. In general, at least two types of receptor operate through calcium permeation: a fast-acting ionotropic receptor channel and a slow-activating metabotropic receptor, added to exchangers/transporters/pumps and intracellular Ca2+ release activated by messengers. These prototypes have gained an enormous amount of information in dynamic signaling circuits. SCCI has also been used as a method to associate phenotypic markers during development and stage transitions in progenitors, stem, vascular cells, neuro- and glioblasts, neurons, astrocytes, oligodendrocytes, and microglia that operate through ion channels, transporters, and receptors. Also, cancer cells or inducible cell lines from human organoids characterized by transition stages are currently being used to model diseases or reconfigure healthy cells in terms of the expression of calcium-binding/permeable molecules and shed light on therapy.
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Affiliation(s)
- Ricardo Augusto de Melo Reis
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hércules Rezende Freitas
- Department of Pathology and Laboratory Medicine, MIND Institute, University of California, Davis, Sacramento, CA, United States
| | - Fernando Garcia de Mello
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Venkateswarlu K, Suman G, Dhyani V, Swain S, Giri L, Samavedi S. Three‐dimensional imaging and quantification of real‐time cytosolic calcium oscillations in microglial cells cultured on electrospun matrices using laser scanning confocal microscopy. Biotechnol Bioeng 2020; 117:3108-3123. [DOI: 10.1002/bit.27465] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/24/2020] [Accepted: 06/16/2020] [Indexed: 12/28/2022]
Affiliation(s)
- Kojja Venkateswarlu
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
| | - Gare Suman
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
| | - Vaibhav Dhyani
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
| | - Sarpras Swain
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
| | - Lopamudra Giri
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
| | - Satyavrata Samavedi
- Department of Chemical Engineering Indian Institute of Technology Hyderabad Sangareddy Telangana India
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Saddala MS, Lennikov A, Mukwaya A, Yang Y, Hill MA, Lagali N, Huang H. Discovery of novel L-type voltage-gated calcium channel blockers and application for the prevention of inflammation and angiogenesis. J Neuroinflammation 2020; 17:132. [PMID: 32334630 PMCID: PMC7183139 DOI: 10.1186/s12974-020-01801-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 04/02/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The ways in which microglia activate and promote neovascularization (NV) are not fully understood. Recent in vivo evidence supports the theory that calcium is required for the transition of microglia from a surveillance state to an active one. The objectives of this study were to discover novel L-type voltage-gated channel (L-VGCC) blockers and investigate their application for the prevention of inflammation and angiogenesis. METHODS Pharmacophore-based computational modeling methods were used to screen for novel calcium channel blockers (CCBs) from the ZINC compound library. The effects of CCBs on calcium blockade, microglial pro-inflammatory activation, and cell toxicity were validated in BV-2 microglial cell and freshly isolated smooth muscle cell (SMC) cultures. Laser-induced choroidal neovascularization (NV) and the suture-induced inflammatory corneal NV models of angiogenesis were used for in vivo validation of the novel CCBs. CX3CR1gfp/+ mice were used to examine the infiltration of GFP-labeled microglial cells. RESULTS We identified three compounds from the ZINC database (Zinc20267861, Zinc18204217, and Zinc33254827) as new blockers of L-type voltage-gated calcium channels (L-VGCC) using a structure-based pharmacophore approach. The effects of the three CCBs on Ca2+ influx into cells were verified in BV-2 microglial cells using Fura-2 fluorescent dye and in freshly isolated SMCs using the voltage-patch clamp. All three CCBs reduced microglial cell migration, activation stimulated by lipopolysaccharide (LPS), and reduced the expression of the inflammatory markers NF-κB (phospho-IκBα) and cyclooxygenase-2 (COX-2) as well as reactive oxygen species. Of the three compounds, we further examined the in vivo activity of Zinc20267861. Topical treatment with Zinc20267861 in a rat model of suture-induced inflammatory cornea neovascularization demonstrated efficacy of the compound in reducing monocyte infiltration and overall corneal NV response. Subconjunctival administration of the compound in the choroidal NV mouse model effectively prevented CNV and microglial infiltration. CONCLUSIONS Our findings suggest that the novel CCBs identified here are effective anti-inflammatory agents that can be further evaluated for treating NV disorders and can be potentially applied in the treatment of ocular inflammatory and pathological angiogenetic disorders.
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Affiliation(s)
- Madhu Sudhana Saddala
- Department of Ophthalmology, School of Medicine, University of Missouri-Columbia, 1 Hospital Drive, MA102C, Columbia, MO, 65212, USA
| | - Anton Lennikov
- Department of Ophthalmology, School of Medicine, University of Missouri-Columbia, 1 Hospital Drive, MA102C, Columbia, MO, 65212, USA
| | - Anthony Mukwaya
- Department of Ophthalmology, Institute for Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Yan Yang
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Michael A Hill
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO, USA
| | - Neil Lagali
- Department of Ophthalmology, Institute for Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden
| | - Hu Huang
- Department of Ophthalmology, School of Medicine, University of Missouri-Columbia, 1 Hospital Drive, MA102C, Columbia, MO, 65212, USA.
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Spencer SA, Suárez-Pozos E, Escalante M, Myo YP, Fuss B. Sodium-Calcium Exchangers of the SLC8 Family in Oligodendrocytes: Functional Properties in Health and Disease. Neurochem Res 2020; 45:1287-1297. [PMID: 31927687 DOI: 10.1007/s11064-019-02949-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022]
Abstract
The solute carrier 8 (SLC8) family of sodium-calcium exchangers (NCXs) functions as an essential regulatory system that couples opposite fluxes of sodium and calcium ions across plasmalemmal membranes. NCXs, thereby, play key roles in maintaining an ion homeostasis that preserves cellular integrity. Hence, alterations in NCX expression and regulation have been found to lead to ionic imbalances that are often associated with intracellular calcium overload and cell death. On the other hand, intracellular calcium has been identified as a key driver for a multitude of downstream signaling events that are crucial for proper functioning of biological systems, thus highlighting the need for a tightly controlled balance. In the CNS, NCXs have been primarily characterized in the context of synaptic transmission and ischemic brain damage. However, a much broader picture is emerging. NCXs are expressed by virtually all cells of the CNS including oligodendrocytes (OLGs), the cells that generate the myelin sheath. With a growing appreciation of dynamic calcium signals in OLGs, NCXs are becoming increasingly recognized for their crucial roles in shaping OLG function under both physiological and pathophysiological conditions. In order to provide a current update, this review focuses on the importance of NCXs in cells of the OLG lineage. More specifically, it provides a brief introduction into plasmalemmal NCXs and their modes of activity, and it discusses the roles of OLG expressed NCXs in regulating CNS myelination and in contributing to CNS pathologies associated with detrimental effects on OLG lineage cells.
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Affiliation(s)
- Samantha A Spencer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Edna Suárez-Pozos
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Miguel Escalante
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.,Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Yu Par Myo
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA, 23298, USA.
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Figarella K, Wolburg H, Garaschuk O, Duszenko M. Microglia in neuropathology caused by protozoan parasites. Biol Rev Camb Philos Soc 2019; 95:333-349. [PMID: 31682077 DOI: 10.1111/brv.12566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/31/2022]
Abstract
Involvement of the central nervous system (CNS) is the most severe consequence of some parasitic infections. Protozoal infections comprise a group of diseases that together affect billions of people worldwide and, according to the World Health Organization, are responsible for more than 500000 deaths annually. They include African and American trypanosomiasis, leishmaniasis, malaria, toxoplasmosis, and amoebiasis. Mechanisms underlying invasion of the brain parenchyma by protozoa are not well understood and may depend on parasite nature: a vascular invasion route is most common. Immunosuppression favors parasite invasion into the CNS and therefore the host immune response plays a pivotal role in the development of a neuropathology in these infectious diseases. In the brain, microglia are the resident immune cells active in defense against pathogens that target the CNS. Beside their direct role in innate immunity, they also play a principal role in coordinating the trafficking and recruitment of other immune cells from the periphery to the CNS. Despite their evident involvement in the neuropathology of protozoan infections, little attention has given to microglia-parasite interactions. This review describes the most prominent features of microglial cells and protozoan parasites and summarizes the most recent information regarding the reaction of microglial cells to parasitic infections. We highlight the involvement of the periphery-brain axis and emphasize possible scenarios for microglia-parasite interactions.
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Affiliation(s)
- Katherine Figarella
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Hartwig Wolburg
- Institute of Pathology and Neuropathology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Michael Duszenko
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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Nicoletti CG, Landi D, Monteleone F, Mataluni G, Albanese M, Lauretti B, Rocchi C, Simonelli I, Boffa L, Buttari F, Mercuri NB, Centonze D, Marfia GA. Treatment with Dimethyl Fumarate Enhances Cholinergic Transmission in Multiple Sclerosis. CNS Drugs 2019; 33:1133-1139. [PMID: 31650471 DOI: 10.1007/s40263-019-00676-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Dimethyl fumarate (DMF) exerts anti-inflammatory effects in multiple sclerosis by activating the Nrf2 antioxidant pathway, which is also stimulated by acetylcholine via alpha-7 nicotinic acetylcholine receptors. In animal models, Nrf2 potentiates cholinergic synaptic plasticity. OBJECTIVE The aim of this study was to test whether treatment with DMF modulates cholinergic pathways in relapsing-remitting multiple sclerosis (RRMS). METHODS Patients starting DMF (20) or IFN-β 1a (20) and healthy subjects (20) were enrolled. Short-latency afferent inhibition (SAI), which is a transcranial stimulation measure of central cholinergic transmission, was recorded in patients and controls at baseline and, in patients only, after 6 months of treatment. Patients treated with DMF also underwent autonomic function testing to further explore peripheral and central cholinergic tone. RESULTS At baseline, SAI was similar in patients and in controls (p = 0.983). Treatment with DMF significantly increased SAI (p = 0.01), while IFNβ had no effect (p = 0.80). In the cold face test, DMF treatment also increased reflex bradycardia (p = 0.013), and reduced diastolic blood pressure variation (p = 0.010), further indicating its ability to stimulate cholinergic transmission. CONCLUSIONS Treatment of MS patients with DMF results in increased cholinergic stimulation, with possible implications for neuroinflammation and neuroprotection.
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Affiliation(s)
- Carolina Gabri Nicoletti
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Doriana Landi
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Fabrizia Monteleone
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Giorgia Mataluni
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Maria Albanese
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Benedetta Lauretti
- Neurology Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Camilla Rocchi
- Neurology Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Ilaria Simonelli
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy.,Service of Medical Statistics and Information Technology, Fondazione Fatebenefratelli per la Ricerca e la Formazione Sanitaria e Sociale, Lungotevere de' Cenci 5, 00186, Rome, Italy
| | - Laura Boffa
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy
| | - Fabio Buttari
- Neurology and Neurorehabilitation Units, IRCCS NEUROMED, Via Atinense 18, 86077, Pozzilli, IS, Italy
| | - Nicola Biagio Mercuri
- Neurology Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy.,Laboratory of Experimental Neurology, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00143, Rome, Italy
| | - Diego Centonze
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy. .,Neurology and Neurorehabilitation Units, IRCCS NEUROMED, Via Atinense 18, 86077, Pozzilli, IS, Italy.
| | - Girolama Alessandra Marfia
- Multiple Sclerosis Clinical and Research Unit, Department of Systems Medicine, Tor Vergata University and Hospital, Via Montpellier 1, 00133, Rome, Italy.,Neurology and Neurorehabilitation Units, IRCCS NEUROMED, Via Atinense 18, 86077, Pozzilli, IS, Italy
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37
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Calcium Signaling in Neurons and Glial Cells: Role of Cav1 channels. Neuroscience 2019; 421:95-111. [DOI: 10.1016/j.neuroscience.2019.09.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 11/18/2022]
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Soldozy S, Sharifi KA, Desai B, Giraldo D, Yeghyayan M, Liu L, Norat P, Sokolowski JD, Yağmurlu K, Park MS, Tvrdik P, Kalani MYS. Cortical Spreading Depression in the Setting of Traumatic Brain Injury. World Neurosurg 2019; 134:50-57. [PMID: 31655239 DOI: 10.1016/j.wneu.2019.10.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/06/2019] [Accepted: 10/08/2019] [Indexed: 12/31/2022]
Abstract
Cortical spreading depression (CSD) is a pathophysiologic phenomenon that describes an expanding wave of depolarization within the cortical gray matter. Originally described over 70 years ago, this spreading depression disrupts neuronal and glial ionic equilibrium, leading to increased energy demands that can cause a metabolic crisis. This results in secondary insult, further perpetuating brain injury and neuronal death. Initially not thought to be of clinical significance, the view of CSD was modified with the advent of intracranial electroencephalography, or electrocorticography. With these improved monitoring techniques, CSD has been identified as a major mechanism by which traumatic brain injury (TBI) imparts its negative sequalae. TBI is a heterogenous disease process that runs the gamut of clinical presentations. This includes concussion, epidural and subdural hematoma, diffuse axonal injury, and subarachnoid hemorrhage. Nonetheless, CSD appears to be frequently occurring among the various types of TBI, thus allowing for the potential development of targeted therapies in an otherwise ill-fated patient cohort. Although a complete understanding of the interplay between CSD and TBI has not yet been achieved, the authors recount the efforts that have been employed over the last several decades in an effort to bridge this gap. In addition, our current understanding of the role neuroimmune cells play in CSD is discussed in the context of TBI. Finally, current therapeutic strategies using CSD as a pharmacologic target are explored with respect to their clinical use in patients with TBI.
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Affiliation(s)
- Sauson Soldozy
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Khadijeh A Sharifi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Bhargav Desai
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Daniel Giraldo
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Michelle Yeghyayan
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Lei Liu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Pedro Norat
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jennifer D Sokolowski
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Kaan Yağmurlu
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Min S Park
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA
| | - M Yashar S Kalani
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA; Department of Neuroscience, University of Virginia Health System, Charlottesville, Virginia, USA.
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Healthy Brain Aging Modifies Microglial Calcium Signaling In Vivo. Int J Mol Sci 2019; 20:ijms20030589. [PMID: 30704036 PMCID: PMC6386999 DOI: 10.3390/ijms20030589] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/11/2019] [Accepted: 01/24/2019] [Indexed: 12/22/2022] Open
Abstract
Brain aging is characterized by a chronic, low-grade inflammatory state, promoting deficits in cognition and the development of age-related neurodegenerative diseases. Malfunction of microglia, the brain-resident immune cells, was suggested to play a critical role in neuroinflammation, but the mechanisms underlying this malfunctional phenotype remain unclear. Specifically, the age-related changes in microglial Ca2+ signaling, known to be linked to its executive functions, are not well understood. Here, using in vivo two-photon imaging, we characterize intracellular Ca2+ signaling and process extension of cortical microglia in young adult (2–4-month-old), middle-aged (9–11-month-old), and old (18–21-month-old) mice. Our data revealed a complex and nonlinear dependency of the properties of intracellular Ca2+ signals on an animal’s age. While the fraction of cells displaying spontaneous Ca2+ transients progressively increased with age, the frequencies and durations of the spontaneous Ca2+ transients followed a bell-shaped relationship, with the most frequent and largest Ca2+ transients seen in middle-aged mice. Moreover, in old mice microglial processes extending toward an ATP source moved faster but in a more disorganized manner, compared to young adult mice. Altogether, these findings identify two distinct phenotypes of aging microglia: a reactive phenotype, abundantly present in middle-aged animals, and a dysfunctional/senescent phenotype ubiquitous in old mice.
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Abstract
Microglia are neural cells of nonneural origin; they originate from fetal macrophages that invade neural tube early in embryogenesis and undergo the most idiosyncratic metamorphosis which coverts them into elements of neural circuitry. Microglia appeared early in evolution with neural immune cells being operative in leeches and mollusks. Microglial cells acquire specific morphology characterized by small cell bodies and long motile processes which are packed with receptors sensing both physiological and pathological stimuli. Microglial cells actively sculpture neuronal networks through synaptic stripping and phagocytosis of redundant neurons; microglia also secrete neuroactive factors regulating synaptic transmission. Novel techniques emerging in recent decade allowed an in-depth understanding of physiological and pathophysiological functions of microglia.
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Affiliation(s)
- Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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41
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Abstract
Genetically encoded calcium indicators (GECIs) have become widely used for Ca2+ imaging in cultured cells as well as in living organisms. Transduction of microglia with viral vectors encoding GECIs provides a convenient means to label microglia for in vivo Ca2+ imaging. We describe a method using microglia-specific microRNA-9-regulated viral vector, to label microglial cells with a ratiometric GECI (Twitch-2B). This method enables longitudinal recording of both transient and sustained elevations of Ca2+ in microglia in live animals.
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Affiliation(s)
- Yajie Liang
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
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42
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Garaschuk O, Semchyshyn HM, Lushchak VI. Healthy brain aging: Interplay between reactive species, inflammation and energy supply. Ageing Res Rev 2018; 43:26-45. [PMID: 29452266 DOI: 10.1016/j.arr.2018.02.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/13/2017] [Accepted: 02/08/2018] [Indexed: 02/07/2023]
Abstract
Brains' high energy expenditure with preferable utilization of glucose and ketone bodies, defines the specific features of its energy homeostasis. The extensive oxidative metabolism is accompanied by a concomitant generation of high amounts of reactive oxygen, nitrogen, and carbonyl species, which will be here collectively referred to as RONCS. Such metabolism in combination with high content of polyunsaturated fatty acids creates specific problems in maintaining brains' redox homeostasis. While the levels of products of interaction between RONCS and cellular components increase slowly during the first two trimesters of individuals' life, their increase is substantially accelerated towards the end of life. Here we review the main mechanisms controlling the redox homeostasis of the mammalian brain, their age-dependencies as well as their adaptive potential, which might turn out to be much higher than initially assumed. According to recent data, the organism seems to respond to the enhancement of aging-related toxicity by forming a new homeostatic set point. Therefore, further research will focus on understanding the properties of the new set point(s), the general nature of this phenomenon and will explore the limits of brains' adaptivity.
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Affiliation(s)
- O Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, 72074 Tübingen, Germany.
| | - H M Semchyshyn
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str, Ivano-Frankivsk, 76018, Ukraine.
| | - V I Lushchak
- Department of Biochemistry and Biotechnology, Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str, Ivano-Frankivsk, 76018, Ukraine.
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43
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Su L, Yimaer A, Xu Z, Chen G. Effects of 1800 MHz RF-EMF exposure on DNA damage and cellular functions in primary cultured neurogenic cells. Int J Radiat Biol 2018; 94:295-305. [PMID: 29368975 DOI: 10.1080/09553002.2018.1432913] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To systematically evaluate the effects of 1800 MHz radiofrequency electromagnetic fields (RF-EMF) exposure on DNA damage and cellular functions in primary cultured neurogenic cells. MATERIALS AND METHODS The primary cultured astrocytes, microglia and cortical neurons were exposed to RF-EMF at a SAR of 4.0 W/kg. The DNA damage was evaluated by γH2AX foci formation assay. The secretions of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) in astrocytes and microglia, microglial phagocytic activity and neuronal development were examined by enzyme-linked immunosorbent assay, phagocytosis assay and immunofluorescent staining on microtubule-associated protein tau, microtubule-associated protein 2, postsynaptic density 95 and gephyrin, respectively. RESULTS RF-EMF exposure did not significantly induce γH2AX foci formation in three primary cultured neurogenic cells. Furthermore, RF-EMF exposure did not significantly affect the secretion of cytokines in astrocytes and microglia, and the morphological indicators of dendrites or synapses of cortical neurons. However, the exposure significantly reduced the phagocytic activity of microglia and inhibited the axon branch length and branch number of cortical neurons. CONCLUSIONS Our data demonstrated that exposure to RF-EMF did not elicit DNA damage but inhibited the phagocytic ability of microglia and the axon branch length and branch number of cortical neurons.
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Affiliation(s)
- Liling Su
- a Bioelectromagnetics Laboratory , Zhejiang University School of Medicine , Hangzhou , PR China.,b Department of Clinical Medicine , Jiangxi Medical College , Shangrao , PR China
| | - Aziguli Yimaer
- a Bioelectromagnetics Laboratory , Zhejiang University School of Medicine , Hangzhou , PR China
| | - Zhengping Xu
- a Bioelectromagnetics Laboratory , Zhejiang University School of Medicine , Hangzhou , PR China
| | - Guangdi Chen
- a Bioelectromagnetics Laboratory , Zhejiang University School of Medicine , Hangzhou , PR China.,c Institute of Environmental Health , Zhejiang University School of Public Health , Hangzhou , PR China
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44
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Thangthaeng N, Poulose SM, Fisher DR, Shukitt-Hale B. Walnut extract modulates activation of microglia through alteration in intracellular calcium concentration. Nutr Res 2017; 49:88-95. [PMID: 29420996 DOI: 10.1016/j.nutres.2017.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/23/2017] [Accepted: 10/27/2017] [Indexed: 12/17/2022]
Abstract
Diets supplemented with walnuts have shown to protect brain against oxidative and inflammatory cytotoxicity and promote protective cellular and cognitive function. The current study was undertaken to test the hypothesize that whole walnut extract (WNE) inhibits lipopolysaccharide (LPS)-induced microglial activation by regulating calmodulin (CaM) expression through [Ca2+]i. To test this hypothesis, we used an in vitro model the highly aggressively proliferating immortalized cells, a rat microglial cell line, treated with various concentrations of WNEs. Treatment with WNE (1.5%, 3%, or 6%) induced a slow rise in intracellular calcium in a concentration- and time-dependent manner, and this rise became exaggerated when cells were depolarized with potassium chloride (100 mmol/L). Cells treated with WNE (1%, 3%, or 6%) upregulated CaM protein levels, with 1 hour posttreatment being the peak time, regardless of WNE concentration. Interestingly, this WNE-induced upregulation of CaM was blocked by pretreatment with thapsigargin. Additionally, treatment with WNE (1%, 3%, or 6%) 1 hour prior to LPS treatment was found to be effective in preventing LPS-induced upregulation of inducible nitric oxide synthase expression, upregulation of ionized Ca2+-binding adaptor-1, and downregulation of CaM. These findings suggest that bioactive compounds in walnut are capable of modulating microglial activation through regulation of intracellular calcium and CaM expression. Nutritional interventions using walnuts may be effective in the amelioration of chronic inflammation and neurodegeneration.
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Affiliation(s)
- Nopporn Thangthaeng
- USDA-ARS, Human Nutrition Research Center on Aging at Tufts University, Boston, MA
| | - Shibu M Poulose
- USDA-ARS, Human Nutrition Research Center on Aging at Tufts University, Boston, MA
| | - Derek R Fisher
- USDA-ARS, Human Nutrition Research Center on Aging at Tufts University, Boston, MA
| | - Barbara Shukitt-Hale
- USDA-ARS, Human Nutrition Research Center on Aging at Tufts University, Boston, MA.
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45
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Doolen S, Cook J, Riedl M, Kitto K, Kohsaka S, Honda CN, Fairbanks CA, Taylor BK, Vulchanova L. Complement 3a receptor in dorsal horn microglia mediates pronociceptive neuropeptide signaling. Glia 2017; 65:1976-1989. [PMID: 28850719 DOI: 10.1002/glia.23208] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/02/2017] [Accepted: 08/04/2017] [Indexed: 01/03/2023]
Abstract
The complement 3a receptor (C3aR1) participates in microglial signaling under pathological conditions and was recently shown to be activated by the neuropeptide TLQP-21. We previously demonstrated that TLQP-21 elicits hyperalgesia and contributes to nerve injury-induced hypersensitivity through an unknown mechanism in the spinal cord. Here we determined that this mechanism requires C3aR1 and that microglia are the cellular target for TLQP-21. We propose a novel neuroimmune signaling pathway involving TLQP-21-induced activation of microglial C3aR1 that then contributes to spinal neuroplasticity and neuropathic pain. This unique dual-ligand activation of C3aR1 by a neuropeptide (TLQP-21) and an immune mediator (C3a) represents a potential broad-spectrum mechanism throughout the CNS for integration of neuroimmune crosstalk at the molecular level.
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Affiliation(s)
- Suzanne Doolen
- Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, Kentucky, 40536-0298
| | - Jennifer Cook
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Maureen Riedl
- Departments of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455
| | - Kelley Kitto
- Departments of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455
| | | | - Christopher N Honda
- Departments of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455
| | - Carolyn A Fairbanks
- Departments of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455.,Departments of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota, 55455.,Departments of Pharmacology, University of Minnesota, Minneapolis, Minnesota, 55455
| | - Bradley K Taylor
- Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, Kentucky, 40536-0298
| | - Lucy Vulchanova
- Departments of Neuroscience, University of Minnesota, Minneapolis, Minnesota, 55455
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46
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Brawek B, Liang Y, Savitska D, Li K, Fomin-Thunemann N, Kovalchuk Y, Zirdum E, Jakobsson J, Garaschuk O. A new approach for ratiometric in vivo calcium imaging of microglia. Sci Rep 2017; 7:6030. [PMID: 28729628 PMCID: PMC5519759 DOI: 10.1038/s41598-017-05952-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/07/2017] [Indexed: 11/09/2022] Open
Abstract
Microglia, resident immune cells of the brain, react to the presence of pathogens/danger signals with a large repertoire of functional responses including morphological changes, proliferation, chemotaxis, production/release of cytokines, and phagocytosis. In vitro studies suggest that many of these effector functions are Ca2+-dependent, but our knowledge about in vivo Ca2+ signalling in microglia is rudimentary. This is mostly due to technical reasons, as microglia largely resisted all attempts of in vivo labelling with Ca2+ indicators. Here, we introduce a novel approach, utilizing a microglia-specific microRNA-9-regulated viral vector, enabling the expression of a genetically-encoded ratiometric Ca2+ sensor Twitch-2B in microglia. The Twitch-2B-assisted in vivo imaging enables recording of spontaneous and evoked microglial Ca2+ signals and allows for the first time to monitor the steady state intracellular Ca2+ levels in microglia. Intact in vivo microglia show very homogenous and low steady state intracellular Ca2+ levels. However, the levels increase significantly after acute slice preparation and cell culturing along with an increase in the expression of activation markers CD68 and IL-1β. These data identify the steady state intracellular Ca2+ level as a versatile microglial activation marker, which is highly sensitive to the cell's environment.
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Affiliation(s)
- Bianca Brawek
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | - Yajie Liang
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | - Daria Savitska
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | - Kaizhen Li
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | | | - Yury Kovalchuk
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | - Elizabeta Zirdum
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany
| | - Johan Jakobsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, 221 84, Sweden
| | - Olga Garaschuk
- Institute of Physiology II, University of Tübingen, 72074, Tübingen, Germany.
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47
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Brawek B, Garaschuk O. Monitoring in vivo function of cortical microglia. Cell Calcium 2017; 64:109-117. [DOI: 10.1016/j.ceca.2017.02.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 02/08/2017] [Indexed: 02/01/2023]
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48
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Mosser CA, Baptista S, Arnoux I, Audinat E. Microglia in CNS development: Shaping the brain for the future. Prog Neurobiol 2017; 149-150:1-20. [DOI: 10.1016/j.pneurobio.2017.01.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/22/2022]
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49
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Sadigh-Eteghad S, Majdi A, Mahmoudi J, Golzari SEJ, Talebi M. Astrocytic and microglial nicotinic acetylcholine receptors: an overlooked issue in Alzheimer's disease. J Neural Transm (Vienna) 2016; 123:1359-1367. [PMID: 27262818 DOI: 10.1007/s00702-016-1580-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/27/2016] [Indexed: 02/01/2023]
Abstract
It is increasingly recognized that astrocytes and microglia-associated dysfunction contribute to AD pathology. In addition, glial nicotinic acetylcholine receptors (nAChRs) play a role in AD-related phenomena, such as neuron survival, synaptic plasticity, and memory. From mechanistic point of view, the glial regulation of pro-inflammatory cytokines, as common contributors in AD, is modulated by nAChRs. Astrocytic and microglial nAChRs contribute to Aβ metabolism, including Aβ phagocytosis and degradation as well as Aβ-related oxidative stress and neurotoxicity. These receptors are also involved in neurotransmission and gliotransmission through indirect interaction with N-Methyl-D-aspartate (NMDA) and a-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid (AMPA) receptors as well as gamma-aminobutyric acid (GABA) and intracellular calcium regulation. In addition, glial nAChRs participate in trophic factors-induced neuroprotection. This review gathers the most recent advances along with the previous data on astrocytic and microglial nAChRs role in AD pathogenesis.
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Affiliation(s)
- Saeed Sadigh-Eteghad
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Alireza Majdi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Javad Mahmoudi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Samad E J Golzari
- Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahnaz Talebi
- Neurosciences Research Center (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
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Fumarates modulate microglia activation through a novel HCAR2 signaling pathway and rescue synaptic dysregulation in inflamed CNS. Acta Neuropathol 2015; 130:279-95. [PMID: 25920452 PMCID: PMC4503882 DOI: 10.1007/s00401-015-1422-3] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/09/2015] [Accepted: 04/09/2015] [Indexed: 11/02/2022]
Abstract
Dimethyl fumarate (DMF), recently approved as an oral immunomodulatory treatment for relapsing-remitting multiple sclerosis (MS), metabolizes to monomethyl fumarate (MMF) which crosses the blood-brain barrier and has demonstrated neuroprotective effects in experimental studies. We postulated that MMF exerts neuroprotective effects through modulation of microglia activation, a critical component of the neuroinflammatory cascade that occurs in neurodegenerative diseases such as MS. To ascertain our hypothesis and define the mechanistic pathways involved in the modulating effect of fumarates, we used real-time PCR and biochemical assays to assess changes in the molecular and functional phenotype of microglia, quantitative Western blotting to monitor activation of postulated pathway components, and ex vivo whole-cell patch clamp recording of excitatory post-synaptic currents in corticostriatal slices from mice with experimental autoimmune encephalomyelitis (EAE), a model for MS, to study synaptic transmission. We show that exposure to MMF switches the molecular and functional phenotype of activated microglia from classically activated, pro-inflammatory type to alternatively activated, neuroprotective one, through activation of the hydroxycarboxylic acid receptor 2 (HCAR2). We validate a downstream pathway mediated through the AMPK-Sirt1 axis resulting in deacetylation, and thereby inhibition, of NF-κB and, consequently, of secretion of pro-inflammatory molecules. We demonstrate through ex vivo monitoring of spontaneous glutamate-mediated excitatory post-synaptic currents of single neurons in corticostriatal slices from EAE mice that the neuroprotective effect of DMF was exerted on neurons at pre-synaptic terminals by modulating glutamate release. By exposing control slices to untreated and MMF-treated activated microglia, we confirm the modulating effect of MMF on microglia function and, thereby, its indirect neuroprotective effect at post-synaptic level. These findings, whereby DMF-induced activation of a new HCAR2-dependent pathway on microglia leads to the modulation of neuroinflammation and restores synaptic alterations occurring in EAE, represent a possible novel mechanism of action for DMF in MS.
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