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Nevelchuk S, Brawek B, Schwarz N, Valiente-Gabioud A, Wuttke TV, Kovalchuk Y, Koch H, Höllig A, Steiner F, Figarella K, Griesbeck O, Garaschuk O. Morphotype-specific calcium signaling in human microglia. J Neuroinflammation 2024; 21:175. [PMID: 39020359 PMCID: PMC11256502 DOI: 10.1186/s12974-024-03169-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
BACKGROUND Key functions of Ca2+ signaling in rodent microglia include monitoring the brain state as well as the surrounding neuronal activity and sensing the danger or damage in their vicinity. Microglial Ca2+ dyshomeostasis is a disease hallmark in many mouse models of neurological disorders but the Ca2+ signal properties of human microglia remain unknown. METHODS We developed a novel genetically-encoded ratiometric Ca2+ indicator, targeting microglial cells in the freshly resected human tissue, organotypically cultured tissue slices and analyzed in situ ongoing Ca2+ signaling of decades-old microglia dwelling in their native microenvironment. RESULTS The data revealed marked compartmentalization of Ca2+ signals, with signal properties differing across the compartments and resident morphotypes. The basal Ca2+ levels were low in ramified and high in ameboid microglia. The fraction of cells with ongoing Ca2+ signaling, the fraction and the amplitude of process Ca2+ signals and the duration of somatic Ca2+ signals decreased when moving from ramified via hypertrophic to ameboid microglia. In contrast, the size of active compartments, the fraction and amplitude of somatic Ca2+ signals and the duration of process Ca2+ signals increased along this pathway.
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Affiliation(s)
- Sofia Nevelchuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ariel Valiente-Gabioud
- Tools for Bio-Imaging, Max-Planck-Institute for Biological Intelligence, Martinsried, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Yury Kovalchuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Henner Koch
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Anke Höllig
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
| | - Frederik Steiner
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Katherine Figarella
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Oliver Griesbeck
- Tools for Bio-Imaging, Max-Planck-Institute for Biological Intelligence, Martinsried, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany.
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Green TRF, Rowe RK. Quantifying microglial morphology: an insight into function. Clin Exp Immunol 2024; 216:221-229. [PMID: 38456795 PMCID: PMC11097915 DOI: 10.1093/cei/uxae023] [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: 08/09/2023] [Revised: 01/17/2024] [Accepted: 03/06/2024] [Indexed: 03/09/2024] Open
Abstract
Microglia are specialized immune cells unique to the central nervous system (CNS). Microglia have a highly plastic morphology that changes rapidly in response to injury or infection. Qualitative and quantitative measurements of ever-changing microglial morphology are considered a cornerstone of many microglia-centric research studies. The distinctive morphological variations seen in microglia are a useful marker of inflammation and severity of tissue damage. Although a wide array of damage-associated microglial morphologies has been documented, the exact functions of these distinct morphologies are not fully understood. In this review, we discuss how microglia morphology is not synonymous with microglia function, however, morphological outcomes can be used to make inferences about microglial function. For a comprehensive examination of the reactive status of a microglial cell, both histological and genetic approaches should be combined. However, the importance of quality immunohistochemistry-based analyses should not be overlooked as they can succinctly answer many research questions.
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Affiliation(s)
- Tabitha R F Green
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
| | - Rachel K Rowe
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
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González-González MA, Conde SV, Latorre R, Thébault SC, Pratelli M, Spitzer NC, Verkhratsky A, Tremblay MÈ, Akcora CG, Hernández-Reynoso AG, Ecker M, Coates J, Vincent KL, Ma B. Bioelectronic Medicine: a multidisciplinary roadmap from biophysics to precision therapies. Front Integr Neurosci 2024; 18:1321872. [PMID: 38440417 PMCID: PMC10911101 DOI: 10.3389/fnint.2024.1321872] [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: 10/16/2023] [Accepted: 01/10/2024] [Indexed: 03/06/2024] Open
Abstract
Bioelectronic Medicine stands as an emerging field that rapidly evolves and offers distinctive clinical benefits, alongside unique challenges. It consists of the modulation of the nervous system by precise delivery of electrical current for the treatment of clinical conditions, such as post-stroke movement recovery or drug-resistant disorders. The unquestionable clinical impact of Bioelectronic Medicine is underscored by the successful translation to humans in the last decades, and the long list of preclinical studies. Given the emergency of accelerating the progress in new neuromodulation treatments (i.e., drug-resistant hypertension, autoimmune and degenerative diseases), collaboration between multiple fields is imperative. This work intends to foster multidisciplinary work and bring together different fields to provide the fundamental basis underlying Bioelectronic Medicine. In this review we will go from the biophysics of the cell membrane, which we consider the inner core of neuromodulation, to patient care. We will discuss the recently discovered mechanism of neurotransmission switching and how it will impact neuromodulation design, and we will provide an update on neuronal and glial basis in health and disease. The advances in biomedical technology have facilitated the collection of large amounts of data, thereby introducing new challenges in data analysis. We will discuss the current approaches and challenges in high throughput data analysis, encompassing big data, networks, artificial intelligence, and internet of things. Emphasis will be placed on understanding the electrochemical properties of neural interfaces, along with the integration of biocompatible and reliable materials and compliance with biomedical regulations for translational applications. Preclinical validation is foundational to the translational process, and we will discuss the critical aspects of such animal studies. Finally, we will focus on the patient point-of-care and challenges in neuromodulation as the ultimate goal of bioelectronic medicine. This review is a call to scientists from different fields to work together with a common endeavor: accelerate the decoding and modulation of the nervous system in a new era of therapeutic possibilities.
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Affiliation(s)
- María Alejandra González-González
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
- Department of Pediatric Neurology, Baylor College of Medicine, Houston, TX, United States
| | - Silvia V. Conde
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NOVA University, Lisbon, Portugal
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stéphanie C. Thébault
- Laboratorio de Investigación Traslacional en salud visual (D-13), Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro, Mexico
| | - Marta Pratelli
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Nicholas C. Spitzer
- Neurobiology Department, Kavli Institute for Brain and Mind, UC San Diego, La Jolla, CA, United States
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
- International Collaborative Center on Big Science Plan for Purinergic Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Cuneyt G. Akcora
- Department of Computer Science, University of Central Florida, Orlando, FL, United States
| | | | - Melanie Ecker
- Department of Biomedical Engineering, University of North Texas, Denton, TX, United States
| | | | - Kathleen L. Vincent
- Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX, United States
| | - Brandy Ma
- Stanley H. Appel Department of Neurology, Houston Methodist Hospital, Houston, TX, United States
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4
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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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Liu J, Peng S, Ye L, Sun Y, Zhao Q, Wei H, Luo Q, He M, Wang G. Neuroinflammation aggravated by traumatic brain injury at high altitude is reversed by L-serine via NFAT1-mediated microglial polarization. Front Cell Neurosci 2023; 17:1152392. [PMID: 37124395 PMCID: PMC10140564 DOI: 10.3389/fncel.2023.1152392] [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: 01/27/2023] [Accepted: 03/24/2023] [Indexed: 05/02/2023] Open
Abstract
Traumatic brain injury (TBI) is one of the main causes of disability and death, especially in plateau areas, where the degree of injury is often more serious than in plain areas. It is likely that high altitude (HA) aggravates neuroinflammation; however, prior studies are limited. This study was designed to evaluate the effects of HA on the degree of TBI and the neuroprotective effects and underlying mechanisms of L-serine against TBI at HA (HA-TBI). In in vivo experiments, wild-type mice and mice with Nfat1 (Nfat1-/- ) deficiency in the C57BL/6 background were kept in a hypobaric chamber for 3 days under simulated conditions of 4,000 m, 6,000 m and 8,000 m above sea level. After leaving the chamber, the standardized TBI model was established immediately. Mice were then intraperitoneally injected with L-serine (342 mg.kg-1) 2 h after TBI and then daily for 5 days. Behavioral tests and histological analysis were assessed at different time points post TBI induction. In vitro, we applied primary cultured microglia for hypoxia treatment (1% O2 for 24 h). The major findings include the following: (1) with increasing altitude, the neurological function of TBI mice decreased, and the damage to cerebral gray matter and white matter became more significant, (2) L-serine significantly improved the sensorimotor function of mice, reversed the increase in brain lesion volume, and promoted the renovation of brain tissue after HA-TBI, (3) L-serine significantly decreased the activation of microglia and promoted microglia polarization toward the protective M2 phenotype both in vivo and in vitro, (4) L-serine significantly suppressed the expression of NFAT1 in mice after HA-TBI and inhibited NFAT1 expression in primary microglia after hypoxia, and (5) knockout of Nfat1 inhibited the inflammatory reaction caused by excessive activation of microglia, and L-serine lost its neuroprotective effect in Nfat1 knockout mice. The present study suggests that HA aggravates brain damage after TBI and that the damage also increases with increasing altitude. As an endogenous amino acid, L-serine may be a neuroprotective agent against HA-TBI, and suppression of NFAT1 in microglia is a potential therapy for neuroinflammation in the future.
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Affiliation(s)
- Jinchun Liu
- Department of Medicine, Henan Vocational College of Nursing, Anyang, Henan, China
- Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Shunhua Peng
- Department of Basic Medicine, Yiyang Medical College, Yiyang, Hunan, China
| | - Lisha Ye
- Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yechao Sun
- Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Qiong Zhao
- Department of Medicine, Henan Vocational College of Nursing, Anyang, Henan, China
| | - Hua Wei
- Department of Medicine, Henan Vocational College of Nursing, Anyang, Henan, China
| | - Qianqian Luo
- Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Min He
- Department of Medicine, Henan Vocational College of Nursing, Anyang, Henan, China
- Department of Scientific Research, Henan Vocational College of Nursing, Anyang, Henan, China
- Min He,
| | - Guohua Wang
- Department of Physiology and Hypoxic Biomedicine, Institute of Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
- *Correspondence: Guohua Wang,
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Grienberger C, Giovannucci A, Zeiger W, Portera-Cailliau C. Two-photon calcium imaging of neuronal activity. NATURE REVIEWS. METHODS PRIMERS 2022; 2:67. [PMID: 38124998 PMCID: PMC10732251 DOI: 10.1038/s43586-022-00147-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/07/2022] [Indexed: 12/23/2023]
Abstract
In vivo two-photon calcium imaging (2PCI) is a technique used for recording neuronal activity in the intact brain. It is based on the principle that, when neurons fire action potentials, intracellular calcium levels rise, which can be detected using fluorescent molecules that bind to calcium. This Primer is designed for scientists who are considering embarking on experiments with 2PCI. We provide the reader with a background on the basic concepts behind calcium imaging and on the reasons why 2PCI is an increasingly powerful and versatile technique in neuroscience. The Primer explains the different steps involved in experiments with 2PCI, provides examples of what ideal preparations should look like and explains how data are analysed. We also discuss some of the current limitations of the technique, and the types of solutions to circumvent them. Finally, we conclude by anticipating what the future of 2PCI might look like, emphasizing some of the analysis pipelines that are being developed and international efforts for data sharing.
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Affiliation(s)
- Christine Grienberger
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, MA, USA
| | - Andrea Giovannucci
- Joint Department of Biomedical Engineering University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
- UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - William Zeiger
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Carlos Portera-Cailliau
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Comparison of Microglial Morphology and Function in Primary Cerebellar Cell Cultures on Collagen and Collagen-Mimetic Hydrogels. Biomedicines 2022; 10:biomedicines10051023. [PMID: 35625762 PMCID: PMC9139096 DOI: 10.3390/biomedicines10051023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/21/2022] [Accepted: 04/26/2022] [Indexed: 12/07/2022] Open
Abstract
Neuronal-glial cell cultures are usually grown attached to or encapsulated in an adhesive environment as evenly distributed networks lacking tissue-like cell density, organization and morphology. In such cultures, microglia have activated amoeboid morphology and do not display extended and intensively branched processes characteristic of the ramified tissue microglia. We have recently described self-assembling functional cerebellar organoids promoted by hydrogels containing collagen-like peptides (CLPs) conjugated to a polyethylene glycol (PEG) core. Spontaneous neuronal activity was accompanied by changes in the microglial morphology and behavior, suggesting the cells might play an essential role in forming the functional neuronal networks in response to the peptide signalling. The present study examines microglial cell morphology and function in cerebellar cell organoid cultures on CLP-PEG hydrogels and compares them to the cultures on crosslinked collagen hydrogels of similar elastomechanical properties. Material characterization suggested more expressed fibril orientation and denser packaging in crosslinked collagen than CLP-PEG. However, CLP-PEG promoted a significantly higher microglial motility (determined by time-lapse imaging) accompanied by highly diverse morphology including the ramified (brightfield and confocal microscopy), more active Ca2+ signalling (intracellular Ca2+ fluorescence recordings), and moderate inflammatory cytokine level (ELISA). On the contrary, on the collagen hydrogels, microglial cells were significantly less active and mostly round-shaped. In addition, the latter hydrogels did not support the neuron synaptic activity. Our findings indicate that the synthetic CLP-PEG hydrogels ensure more tissue-like microglial morphology, motility, and function than the crosslinked collagen substrates.
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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: 28] [Impact Index Per Article: 9.3] [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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Augusto-Oliveira M, Arrifano GP, Delage CI, Tremblay MÈ, Crespo-Lopez ME, Verkhratsky A. Plasticity of microglia. Biol Rev Camb Philos Soc 2021; 97:217-250. [PMID: 34549510 DOI: 10.1111/brv.12797] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Microglial cells are the scions of foetal macrophages which invade the neural tube early during embryogenesis. The nervous tissue environment instigates the phenotypic metamorphosis of foetal macrophages into idiosyncratic surveilling microglia, which are generally characterised by a small cell body and highly ramified motile processes that constantly scan the nervous tissue for signs of changes in homeostasis and allow microglia to perform crucial homeostatic functions. The surveilling microglial phenotype is evolutionarily conserved from early invertebrates to humans. Despite this evolutionary conservation, microglia show substantial heterogeneity in their gene and protein expression, as well as morphological appearance. These differences are age, region and context specific and reflect a high degree of plasticity underlying the life-long adaptation of microglia, supporting the exceptional adaptive capacity of the central nervous system. Microgliocytes are essential elements of cellular network formation and refinement in the developing nervous tissue. Several distinct patrolling modes of microglial processes contribute to the formation, modification, and pruning of synapses; to the support and protection of neurones through microglial-somatic junctions; and to the control of neuronal and axonal excitability by specific microglia-axonal contacts. In pathology, microglia undergo proliferation and reactive remodelling known as microgliosis, which is context dependent, yet represents an evolutionarily conserved defence response. Microgliosis results in the emergence of multiple disease and context-specific reactive states; in addition, neuropathology is associated with the appearance of specific protective or recovery microglial forms. In summary, the plasticity of microglia supports the development and functional activity of healthy nervous tissue and provides highly sophisticated defences against disease.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Charlotte Isabelle Delage
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada.,Neurology and Neurosurgery Department, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.,Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Bureau 4835, 1050 Avenue de la Médecine, Québec City, QC, G1V 0A6, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.,Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania
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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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11
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Redmon SN, Yarishkin O, Lakk M, Jo A, Mustafić E, Tvrdik P, Križaj D. TRPV4 channels mediate the mechanoresponse in retinal microglia. Glia 2021; 69:1563-1582. [PMID: 33624376 PMCID: PMC8989051 DOI: 10.1002/glia.23979] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 12/12/2022]
Abstract
The physiological and neurological correlates of plummeting brain osmolality during edema, traumatic CNS injury, and severe ischemia are compounded by neuroinflammation. Using multiple approaches, we investigated how retinal microglia respond to challenges mediated by increases in strain, osmotic gradients, and agonists of the stretch-activated cation channel TRPV4. Dissociated and intact microglia were TRPV4-immunoreactive and responded to the selective agonist GSK1016790A and substrate stretch with altered motility and elevations in intracellular calcium ([Ca2+ ]i ). Agonist- and hypotonicity-induced swelling was associated with a nonselective outwardly rectifying cation current, increased [Ca2+ ]i , and retraction of higher-order processes. The antagonist HC067047 reduced the extent of hypotonicity-induced microglial swelling and inhibited the suppressive effects of GSK1016790A and hypotonicity on microglial branching. Microglial TRPV4 signaling required intermediary activation of phospholipase A2 (PLA2), cytochrome P450, and epoxyeicosatrienoic acid production (EETs). The expression pattern of vanilloid thermoTrp genes in retinal microglia was markedly different from retinal neurons, astrocytes, and cortical microglia. These results suggest that TRPV4 represents a primary retinal microglial sensor of osmochallenges under physiological and pathological conditions. Its activation, associated with PLA2, modulates calcium signaling and cell architecture. TRPV4 inhibition might be a useful strategy to suppress microglial overactivation in the swollen and edematous CNS.
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Affiliation(s)
- Sarah N Redmon
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Andrew Jo
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Edin Mustafić
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, USA.,Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA.,Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA
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12
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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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13
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Cheng H, Tong S, Deng X, Li J, Qiu P, Wang K. In vivo deep-brain imaging of microglia enabled by three-photon fluorescence microscopy. OPTICS LETTERS 2020; 45:5271-5274. [PMID: 32932509 DOI: 10.1364/ol.408329] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Microglia act as the first and main form of active immune defense in brain. However, in animal models, research on these cells is limited to the superficial layer of the brain, due to the lack of a deep-imaging technique. Here we break this depth limit using three-photon fluorescence (3PF) microscopy excited at the 1700-nm window. Three-photon action cross-section (ησ3) measurement lays the basis for dye selection and the resultant maximization of 3PF generation. 3PF imaging suppresses the surface background, leading to a much improved signal-to-background ratio compared to the commonly used two-photon microscopy (2PM). We can image microglia 1124 µm below the brain surface in vivo, 3.7 times deeper than previous results using 2PM for microglia imaging. This technique enables us to visualize microglia in the white matter layer in vivo for the first time.
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14
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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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15
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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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16
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Kyrargyri V, Attwell D, Jolivet RB, Madry C. Analysis of Signaling Mechanisms Regulating Microglial Process Movement. Methods Mol Biol 2019; 2034:191-205. [PMID: 31392686 DOI: 10.1007/978-1-4939-9658-2_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microglia, the brain's innate immune cells, are extremely motile cells, continuously surveying the central nervous system (CNS) to serve homeostatic functions and to respond to pathological events. In the healthy brain, microglia exhibit a small cell body with long, branched, and highly motile processes, which constantly extend and retract, effectively "patrolling" the brain parenchyma. Over the last decade, methodological advances in microscopy and the availability of genetically encoded reporter mice have allowed us to probe microglial physiology in situ. Beyond their classical immunological roles, unexpected functions of microglia have been revealed, both in the developing and the adult brain: microglia regulate the generation of newborn neurons, control the formation and elimination of synapses, and modulate neuronal activity. Many of these newly ascribed functions depend directly on microglial process movement. Thus, elucidating the mechanisms underlying microglial motility is of great importance to understand their role in brain physiology and pathophysiology. Two-photon imaging of fluorescently labeled microglia, either in vivo or ex vivo in acute brain slices, has emerged as an indispensable tool for investigating microglial movements and their functional consequences. This chapter aims to provide a detailed description of the experimental data acquisition and analysis needed to address these questions, with a special focus on key dynamic and morphological metrics such as surveillance, directed motility, and ramification.
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Affiliation(s)
- Vasiliki Kyrargyri
- Department of Immunology, Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Renaud Blaise Jolivet
- Département de Physique Nucléaire et Corpusculaire, University of Geneva, Geneva, Switzerland
- CERN, Geneva, Switzerland
| | - Christian Madry
- Institute of Neurophysiology, Charité-Universitätsmedizin, Berlin, Germany.
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17
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Baez-Jurado E, Rincón-Benavides MA, Hidalgo-Lanussa O, Guio-Vega G, Ashraf GM, Sahebkar A, Echeverria V, Garcia-Segura LM, Barreto GE. Molecular mechanisms involved in the protective actions of Selective Estrogen Receptor Modulators in brain cells. Front Neuroendocrinol 2019; 52:44-64. [PMID: 30223003 DOI: 10.1016/j.yfrne.2018.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/09/2018] [Accepted: 09/12/2018] [Indexed: 02/06/2023]
Abstract
Synthetic selective modulators of the estrogen receptors (SERMs) have shown to protect neurons and glial cells against toxic insults. Among the most relevant beneficial effects attributed to these compounds are the regulation of inflammation, attenuation of astrogliosis and microglial activation, prevention of excitotoxicity and as a consequence the reduction of neuronal cell death. Under pathological conditions, the mechanism of action of the SERMs involves the activation of estrogen receptors (ERs) and G protein-coupled receptor for estrogens (GRP30). These receptors trigger neuroprotective responses such as increasing the expression of antioxidants and the activation of kinase-mediated survival signaling pathways. Despite the advances in the knowledge of the pathways activated by the SERMs, their mechanism of action is still not entirely clear, and there are several controversies. In this review, we focused on the molecular pathways activated by SERMs in brain cells, mainly astrocytes, as a response to treatment with raloxifene and tamoxifen.
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Affiliation(s)
- E Baez-Jurado
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - M A Rincón-Benavides
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - O Hidalgo-Lanussa
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - G Guio-Vega
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - G M Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - A Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - V Echeverria
- Universidad San Sebastián, Fac. Cs de la Salud, Lientur 1457, Concepción 4080871, Chile; Research & Development Service, Bay Pines VA Healthcare System, Bay Pines, FL 33744, USA
| | - L M Garcia-Segura
- Instituto Cajal, CSIC, Madrid, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - G E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
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18
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Abstract
Microglial cells derive from fetal macrophages which immigrate into and disseminate throughout the central nervous system (CNS) in early embryogenesis. After settling in the nerve tissue, microglial progenitors acquire an idiosyncratic morphological phenotype with small cell body and moving thin and highly ramified processes currently defined as "resting or surveillant microglia". Physiology of microglia is manifested by second messenger-mediated cellular excitability, low resting membrane conductance, and expression of receptors to pathogen- or damage-associated molecular patterns (PAMPs and DAMPs), as well as receptors to classical neurotransmitters and neurohormones. This specific physiological profile reflects adaptive changes of myeloid cells to the CNS environment.
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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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19
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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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20
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Hierro-Bujalance C, Bacskai BJ, Garcia-Alloza M. In Vivo Imaging of Microglia With Multiphoton Microscopy. Front Aging Neurosci 2018; 10:218. [PMID: 30072888 PMCID: PMC6060250 DOI: 10.3389/fnagi.2018.00218] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/26/2018] [Indexed: 01/04/2023] Open
Abstract
Neuroimaging has become an unparalleled tool to understand the central nervous system (CNS) anatomy, physiology and neurological diseases. While an altered immune function and microglia hyperactivation are common neuropathological features for many CNS disorders and neurodegenerative diseases, direct assessment of the role of microglial cells remains a challenging task. Non-invasive neuroimaging techniques, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single positron emission computed tomography (SPECT) are widely used for human clinical applications, and a variety of ligands are available to detect neuroinflammation. In animal models, intravital imaging has been largely used, and minimally invasive multiphoton microcopy (MPM) provides high resolution detection of single microglia cells, longitudinally, in living brain. In this study, we review in vivo real-time MPM approaches to assess microglia in preclinical studies, including individual cell responses in surveillance, support, protection and restoration of brain tissue integrity, synapse formation, homeostasis, as well as in different pathological situations. We focus on in vivo studies that assess the role of microglia in mouse models of Alzheimer’s disease (AD), analyzing microglial motility and recruitment, as well as the role of microglia in anti-amyloid-β treatment, as a key therapeutic approach to treat AD. Altogether, MPM provides a high contrast and high spatial resolution approach to follow microglia chronically in vivo in complex models, supporting MPM as a powerful tool for deep intravital tissue imaging.
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Affiliation(s)
- Carmen Hierro-Bujalance
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
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21
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Lannes N, Eppler E, Etemad S, Yotovski P, Filgueira L. Microglia at center stage: a comprehensive review about the versatile and unique residential macrophages of the central nervous system. Oncotarget 2017; 8:114393-114413. [PMID: 29371994 PMCID: PMC5768411 DOI: 10.18632/oncotarget.23106] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/15/2017] [Indexed: 02/07/2023] Open
Abstract
Microglia cells are the unique residential macrophages of the central nervous system (CNS). They have a special origin, as they derive from the embryonic yolk sac and enter the developing CNS at a very early stage. They play an important role during CNS development and adult homeostasis. They have a major contribution to adult neurogenesis and neuroinflammation. Thus, they participate in the pathogenesis of neurodegenerative diseases and contribute to aging. They play an important role in sustaining and breaking the blood-brain barrier. As innate immune cells, they contribute substantially to the immune response against infectious agents affecting the CNS. They play also a major role in the growth of tumours of the CNS. Microglia are consequently the key cell population linking the nervous and the immune system. This review covers all different aspects of microglia biology and pathology in a comprehensive way.
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Affiliation(s)
- Nils Lannes
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Elisabeth Eppler
- Pestalozzistrasse Zo, Department of BioMedicine, University of Basel, CH-4056 Basel, Switzerland
| | - Samar Etemad
- Building 71/218 RBWH Herston, Centre for Clinical Research, The University of Queensland, QLD 4029 Brisbane, Australia
| | - Peter Yotovski
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Luis Filgueira
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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22
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de Lange ECM, van den Brink W, Yamamoto Y, de Witte WEA, Wong YC. Novel CNS drug discovery and development approach: model-based integration to predict neuro-pharmacokinetics and pharmacodynamics. Expert Opin Drug Discov 2017; 12:1207-1218. [PMID: 28933618 DOI: 10.1080/17460441.2017.1380623] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION CNS drug development has been hampered by inadequate consideration of CNS pharmacokinetic (PK), pharmacodynamics (PD) and disease complexity (reductionist approach). Improvement is required via integrative model-based approaches. Areas covered: The authors summarize factors that have played a role in the high attrition rate of CNS compounds. Recent advances in CNS research and drug discovery are presented, especially with regard to assessment of relevant neuro-PK parameters. Suggestions for further improvements are also discussed. Expert opinion: Understanding time- and condition dependent interrelationships between neuro-PK and neuro-PD processes is key to predictions in different conditions. As a first screen, it is suggested to use in silico/in vitro derived molecular properties of candidate compounds and predict concentration-time profiles of compounds in multiple compartments of the human CNS, using time-course based physiology-based (PB) PK models. Then, for selected compounds, one can include in vitro drug-target binding kinetics to predict target occupancy (TO)-time profiles in humans. This will improve neuro-PD prediction. Furthermore, a pharmaco-omics approach is suggested, providing multilevel and paralleled data on systems processes from individuals in a systems-wide manner. Thus, clinical trials will be better informed, using fewer animals, while also, needing fewer individuals and samples per individual for proof of concept in humans.
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Affiliation(s)
- Elizabeth C M de Lange
- a Leiden Academic Center of Drug Research, Translational Pharmacology , Leiden University , Leiden , The Netherlands
| | - Willem van den Brink
- a Leiden Academic Center of Drug Research, Translational Pharmacology , Leiden University , Leiden , The Netherlands
| | - Yumi Yamamoto
- a Leiden Academic Center of Drug Research, Translational Pharmacology , Leiden University , Leiden , The Netherlands
| | - Wilhelmus E A de Witte
- a Leiden Academic Center of Drug Research, Translational Pharmacology , Leiden University , Leiden , The Netherlands
| | - Yin Cheong Wong
- a Leiden Academic Center of Drug Research, Translational Pharmacology , Leiden University , Leiden , The Netherlands
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23
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Abstract
Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integrate and/or respond to sensory cues. In contrast, zebrafish (Danio rerio) possess an endogenous capacity to regenerate lost neurons. Here, we will focus on the processes that lead to neuronal regeneration in the zebrafish retina. Dying retinal neurons release a damage signal, tumor necrosis factor α, which induces the resident radial glia, the Müller glia, to reprogram and re-enter the cell cycle. The Müller glia divide asymmetrically to produce a Müller glia that exits the cell cycle and a neuronal progenitor cell. The arising neuronal progenitor cells undergo several rounds of cell divisions before they migrate to the site of damage to differentiate into the neuronal cell types that were lost. Molecular and immunohistochemical studies have predominantly provided insight into the mechanisms that regulate retinal regeneration. However, many processes during retinal regeneration are dynamic and require live-cell imaging to fully discern the underlying mechanisms. Recently, a multiphoton imaging approach of adult zebrafish retinal cultures was developed. We will discuss the use of live-cell imaging, the currently available tools and those that need to be developed to advance our knowledge on major open questions in the field of retinal regeneration.
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Affiliation(s)
- Manuela Lahne
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - David R Hyde
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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