1
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Gellner AK, Reis J, Fiebich BL, Fritsch B. Cx3cr1 deficiency interferes with learning- and direct current stimulation-mediated neuroplasticity of the motor cortex. Eur J Neurosci 2024; 59:177-191. [PMID: 38049944 DOI: 10.1111/ejn.16206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/18/2023] [Accepted: 11/12/2023] [Indexed: 12/06/2023]
Abstract
Microglia are essential contributors to synaptic transmission and stability and communicate with neurons via the fractalkine pathway. Transcranial direct current stimulation [(t)DCS], a form of non-invasive electrical brain stimulation, modulates cortical excitability and promotes neuroplasticity, which has been extensively demonstrated in the motor cortex and for motor learning. The role of microglia and their fractalkine receptor CX3CR1 in motor cortical neuroplasticity mediated by DCS or motor learning requires further elucidation. We demonstrate the effects of pharmacological microglial depletion and genetic Cx3cr1 deficiency on the induction of DCS-induced long-term potentiation (DCS-LTP) ex vivo. The relevance of microglia-neuron communication for DCS response and structural neuroplasticity underlying motor learning are assessed via 2-photon in vivo imaging. The behavioural consequences of impaired CX3CR1 signalling are investigated for both gross and fine motor learning. We show that DCS-mediated neuroplasticity in the motor cortex depends on the presence of microglia and is driven in part by CX3CR1 signalling ex vivo and provide the first evidence of microglia interacting with neurons during DCS in vivo. Furthermore, CX3CR1 signalling is required for motor learning and underlying structural neuroplasticity in concert with microglia interaction. Although we have recently demonstrated the microglial response to DCS in vivo, we now provide a link between microglial integrity and neuronal activity for the expression of DCS-dependent neuroplasticity. In addition, we extend the knowledge on the relevance of CX3CR1 signalling for motor learning and structural neuroplasticity. The underlying molecular mechanisms and the potential impact of DCS in rescuing CX3CR1 deficits remain to be addressed in the future.
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Affiliation(s)
- Anne-Kathrin Gellner
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
- Department of Neurology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Institute of Physiology II, Medical Faculty, University of Bonn, Bonn, Germany
| | - Janine Reis
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
| | - Bernd L Fiebich
- Neurochemistry and Neuroimmunology Research Group, Department of Psychiatry and Psychotherapy, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Brita Fritsch
- Department of Psychiatry and Psychotherapy, University Hospital Bonn, Bonn, Germany
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2
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Moya-Gómez A, Font LP, Burlacu A, Alpizar YA, Cardonne MM, Brône B, Bronckaers A. Extremely Low-Frequency Electromagnetic Stimulation (ELF-EMS) Improves Neurological Outcome and Reduces Microglial Reactivity in a Rodent Model of Global Transient Stroke. Int J Mol Sci 2023; 24:11117. [PMID: 37446295 DOI: 10.3390/ijms241311117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Extremely low-frequency electromagnetic stimulation (ELF-EMS) was demonstrated to be significantly beneficial in rodent models of permanent stroke. The mechanism involved enhanced cerebrovascular perfusion and endothelial cell nitric oxide production. However, the possible effect on the neuroinflammatory response and its efficacy in reperfusion stroke models remains unclear. To evaluate ELF-EMS effectiveness and possible immunomodulatory response, we studied neurological outcome, behavior, neuronal survival, and glial reactivity in a rodent model of global transient stroke treated with 13.5 mT/60 Hz. Next, we studied microglial cells migration and, in organotypic hippocampal brain slices, we assessed neuronal survival and microglia reactivity. ELF-EMS improved the neurological score and behavior in the ischemia-reperfusion model. It also improved neuronal survival and decreased glia reactivity in the hippocampus, with microglia showing the first signs of treatment effect. In vitro ELF-EMS decreased (Lipopolysaccharide) LPS and ATP-induced microglia migration in both scratch and transwell assay. Additionally, in hippocampal brain slices, reduced microglial reactivity, improved neuronal survival, and modulation of inflammation-related markers was observed. Our study is the first to show that an EMF treatment has a direct impact on microglial migration. Furthermore, ELF-EMS has beneficial effects in an ischemia/reperfusion model, which indicates that this treatment has clinical potential as a new treatment against ischemic stroke.
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Affiliation(s)
- Amanda Moya-Gómez
- BIOMED, UHasselt, Agoralaan, 3590 Diepenbeek, Belgium
- Biomedical Engineering Department, Facultad de Ingeniería Informática, Telecomunicaciones y Biomédica, Universidad de Oriente, Santiago de Cuba 90 400, Cuba
| | - Lena Pérez Font
- Centro Nacional de Electromagnetismo Aplicado, Universidad de Oriente, Santiago de Cuba 90 400, Cuba
| | | | | | - Miriam Marañón Cardonne
- Biomedical Engineering Department, Facultad de Ingeniería Informática, Telecomunicaciones y Biomédica, Universidad de Oriente, Santiago de Cuba 90 400, Cuba
| | - Bert Brône
- BIOMED, UHasselt, Agoralaan, 3590 Diepenbeek, Belgium
| | - Annelies Bronckaers
- Biomedical Engineering Department, Facultad de Ingeniería Informática, Telecomunicaciones y Biomédica, Universidad de Oriente, Santiago de Cuba 90 400, Cuba
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3
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Bosch LFP, Kierdorf K. The Shape of μ—How Morphological Analyses Shape the Study of Microglia. Front Cell Neurosci 2022; 16:942462. [PMID: 35846562 PMCID: PMC9276927 DOI: 10.3389/fncel.2022.942462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/13/2022] [Indexed: 11/14/2022] Open
Abstract
Microglia, the innate immune cells of the CNS parenchyma, serve as the first line of defense in a myriad of neurodevelopmental, neurodegenerative, and neuroinflammatory conditions. In response to the peripheral inflammation, circulating mediators, and other external signals that are produced by these conditions, microglia dynamically employ different transcriptional programs as well as morphological adaptations to maintain homeostasis. To understand these cells’ function, the field has established a number of essential analysis approaches, such as gene expression, cell quantification, and morphological reconstruction. Although high-throughput approaches are becoming commonplace in regard to other types of analyses (e.g., single-cell scRNA-seq), a similar standard for morphological reconstruction has yet to be established. In this review, we offer an overview of microglial morphological analysis methods, exploring the advantages and disadvantages of each, highlighting a number of key studies, and emphasizing how morphological analysis has significantly contributed to our understanding of microglial function in the CNS parenchyma. In doing so, we advocate for the use of unbiased, automated morphological reconstruction approaches in future studies, in order to capitalize on the valuable information embedded in the cellular structures microglia inhabit.
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Affiliation(s)
- Lance Fredrick Pahutan Bosch
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Katrin Kierdorf
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS–Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- *Correspondence: Katrin Kierdorf,
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4
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Bredehöft J, Dolga AM, Honrath B, Wache S, Mazurek S, Culmsee C, Schoemaker RG, Gerstberger R, Roth J, Rummel C. SK-Channel Activation Alters Peripheral Metabolic Pathways in Mice, but Not Lipopolysaccharide-Induced Fever or Inflammation. J Inflamm Res 2022; 15:509-531. [PMID: 35115803 PMCID: PMC8800008 DOI: 10.2147/jir.s338812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/25/2021] [Indexed: 12/19/2022] Open
Abstract
Purpose Previously, we have shown that CyPPA (cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine), a pharmacological small-conductance calcium-activated potassium (SK)–channel positive modulator, antagonizes lipopolysaccharide (LPS)-induced cytokine expression in microglial cells. Here, we aimed to test its therapeutic potential for brain-controlled sickness symptoms, brain inflammatory response during LPS-induced systemic inflammation, and peripheral metabolic pathways in mice. Methods Mice were pretreated with CyPPA (15 mg/kg IP) 24 hours before and simultaneously with LPS stimulation (2.5 mg/kg IP), and the sickness response was recorded by a telemetric system for 24 hours. A second cohort of mice were euthanized 2 hours after CyPPA or solvent treatment to assess underlying CyPPA-induced mechanisms. Brain, blood, and liver samples were analyzed for inflammatory mediators or nucleotide concentrations using immunohistochemistry, real-time PCR and Western blot, or HPLC. Moreover, we investigated CyPPA-induced changes of UCP1 expression in brown adipose tissue (BAT)–explant cultures. Results CyPPA treatment did not affect LPS-induced fever, anorexia, adipsia, or expression profiles of inflammatory mediators in the hypothalamus or plasma or microglial reactivity to LPS (CD11b staining and CD68 mRNA expression). However, CyPPA alone induced a rise in core body temperature linked to heat production via altered metabolic pathways like reduced levels of adenosine, increased protein content, and increased UCP1 expression in BAT-explant cultures, but no alteration in ATP/ADP concentrations in the liver. CyPPA treatment was accompanied by altered pathways, including NFκB signaling, in the hypothalamus and cortex, while circulating cytokines remained unaltered. Conclusion Overall, while CyPPA has promise as a treatment strategy, in particular according to results from in vitro experiments, we did not reveal anti-inflammatory effects during severe LPS-induced systemic inflammation. Interestingly, we found that CyPPA alters metabolic pathways inducing short hyperthermia, most likely due to increased energy turnover in the liver and heat production in BAT.
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Affiliation(s)
- Janne Bredehöft
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Birgit Honrath
- Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Sybille Wache
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Sybille Mazurek
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Carsten Culmsee
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
| | - Regien G Schoemaker
- Department of Neurobiology, GELIFES, University of Groningen, Groningen, Netherlands
| | - Rüdiger Gerstberger
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
| | - Joachim Roth
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Giessen, Germany
- Center for Mind, Brain and Behavior-CMBB, Giessen and Marburg, Germany
- Correspondence: Christoph Rummel Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, Frankfurter Strasse 100, GiessenD-35392, GermanyTel +49 641 99 38155Fax +49 641 99 38159 Email
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5
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Hohmann U, Dehghani F, Hohmann T. Assessment of Neuronal Damage in Brain Slice Cultures Using Machine Learning Based on Spatial Features. Front Neurosci 2021; 15:740178. [PMID: 34690679 PMCID: PMC8531652 DOI: 10.3389/fnins.2021.740178] [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: 07/12/2021] [Accepted: 09/06/2021] [Indexed: 01/02/2023] Open
Abstract
Neuronal damage presents a major health issue necessitating extensive research to identify mechanisms of neuronal cell death and potential therapeutic targets. Commonly used models are slice cultures out of different brain regions extracted from mice or rats, excitotoxically, ischemic, or traumatically lesioned and subsequently treated with potential neuroprotective agents. Thereby cell death is regularly assessed by measuring the propidium iodide (PI) uptake or counting of PI-positive nuclei. The applied methods have a limited applicability, either in terms of objectivity and time consumption or regarding its applicability. Consequently, new tools for analysis are needed. Here, we present a framework to mimic manual counting using machine learning algorithms as tools for semantic segmentation of PI-positive dead cells in hippocampal slice cultures. Therefore, we trained a support vector machine (SVM) to classify images into either “high” or “low” neuronal damage and used naïve Bayes, discriminant analysis, random forest, and a multilayer perceptron (MLP) as classifiers for segmentation of dead cells. In our final models, pixel-wise accuracies of up to 0.97 were achieved using the MLP classifier. Furthermore, a SVM-based post-processing step was introduced to differentiate between false-positive and false-negative detections using morphological features. As only very few false-positive objects and thus training data remained when using the final model, this approach only mildly improved the results. A final object splitting step using Hough transformations was used to account for overlap, leading to a recall of up to 97.6% of the manually assigned PI-positive dead cells. Taken together, we present an analysis tool that can help to objectively and reproducibly analyze neuronal damage in brain-derived slice cultures, taking advantage of the morphology of pycnotic cells for segmentation, object splitting, and identification of false positives.
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Affiliation(s)
- Urszula Hohmann
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Faramarz Dehghani
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Tim Hohmann
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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6
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Azam S, Haque ME, Balakrishnan R, Kim IS, Choi DK. The Ageing Brain: Molecular and Cellular Basis of Neurodegeneration. Front Cell Dev Biol 2021; 9:683459. [PMID: 34485280 PMCID: PMC8414981 DOI: 10.3389/fcell.2021.683459] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 07/14/2021] [Indexed: 12/12/2022] Open
Abstract
Ageing is an inevitable event in the lifecycle of all organisms, characterized by progressive physiological deterioration and increased vulnerability to death. Ageing has also been described as the primary risk factor of most neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and frontotemporal lobar dementia (FTD). These neurodegenerative diseases occur more prevalently in the aged populations. Few effective treatments have been identified to treat these epidemic neurological crises. Neurodegenerative diseases are associated with enormous socioeconomic and personal costs. Here, the pathogenesis of AD, PD, and other neurodegenerative diseases has been presented, including a summary of their known associations with the biological hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, cellular senescence, deregulated nutrient sensing, stem cell exhaustion, and altered intercellular communications. Understanding the central biological mechanisms that underlie ageing is important for identifying novel therapeutic targets for neurodegenerative diseases. Potential therapeutic strategies, including the use of NAD+ precursors, mitophagy inducers, and inhibitors of cellular senescence, has also been discussed.
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Affiliation(s)
- Shofiul Azam
- Department of Applied Life Sciences, Graduate School, BK21 Program, Konkuk University, Chungju-si, South Korea
| | - Md. Ezazul Haque
- Department of Applied Life Sciences, Graduate School, BK21 Program, Konkuk University, Chungju-si, South Korea
| | - Rengasamy Balakrishnan
- Department of Applied Life Sciences, Graduate School, BK21 Program, Konkuk University, Chungju-si, South Korea
| | - In-Su Kim
- Department of Biotechnology, College of Biomedical and Health Science, Research Institute of Inflammatory Disease (RID), Konkuk University, Chungju-si, South Korea
| | - Dong-Kug Choi
- Department of Applied Life Sciences, Graduate School, BK21 Program, Konkuk University, Chungju-si, South Korea
- Department of Biotechnology, College of Biomedical and Health Science, Research Institute of Inflammatory Disease (RID), Konkuk University, Chungju-si, South Korea
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7
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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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8
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Delbridge ARD, Huh D, Brickelmaier M, Burns JC, Roberts C, Challa R, Raymond N, Cullen P, Carlile TM, Ennis KA, Liu M, Sun C, Allaire NE, Foos M, Tsai HH, Franchimont N, Ransohoff RM, Butts C, Mingueneau M. Organotypic Brain Slice Culture Microglia Exhibit Molecular Similarity to Acutely-Isolated Adult Microglia and Provide a Platform to Study Neuroinflammation. Front Cell Neurosci 2020; 14:592005. [PMID: 33473245 PMCID: PMC7812919 DOI: 10.3389/fncel.2020.592005] [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: 08/06/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Microglia are central nervous system (CNS) resident immune cells that have been implicated in neuroinflammatory pathogenesis of a variety of neurological conditions. Their manifold context-dependent contributions to neuroinflammation are only beginning to be elucidated, which can be attributed in part to the challenges of studying microglia in vivo and the lack of tractable in vitro systems to study microglia function. Organotypic brain slice cultures offer a tissue-relevant context that enables the study of CNS resident cells and the analysis of brain slice microglial phenotypes has provided important insights, in particular into neuroprotective functions. Here we use RNA sequencing, direct digital quantification of gene expression with nCounter® technology and targeted analysis of individual microglial signature genes, to characterize brain slice microglia relative to acutely-isolated counterparts and 2-dimensional (2D) primary microglia cultures, a widely used in vitro surrogate. Analysis using single cell and population-based methods found brain slice microglia exhibited better preservation of canonical microglia markers and overall gene expression with stronger fidelity to acutely-isolated adult microglia, relative to in vitro cells. We characterized the dynamic phenotypic changes of brain slice microglia over time, after plating in culture. Mechanical damage associated with slice preparation prompted an initial period of inflammation, which resolved over time. Based on flow cytometry and gene expression profiling we identified the 2-week timepoint as optimal for investigation of microglia responses to exogenously-applied stimuli as exemplified by treatment-induced neuroinflammatory changes observed in microglia following LPS, TNF and GM-CSF addition to the culture medium. Altogether these findings indicate that brain slice cultures provide an experimental system superior to in vitro culture of microglia as a surrogate to investigate microglia functions, and the impact of soluble factors and cellular context on their physiology.
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Affiliation(s)
- Alex R D Delbridge
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States.,Biogen Postdoctoral Scientist Program, Biogen, Cambridge, MA, United States
| | - Dann Huh
- Translational Biology, Biogen, Cambridge, MA, United States
| | - Margot Brickelmaier
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
| | - Jeremy C Burns
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
| | - Chris Roberts
- Translational Biology, Biogen, Cambridge, MA, United States
| | - Ravi Challa
- Translational Biology, Biogen, Cambridge, MA, United States
| | - Naideline Raymond
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
| | - Patrick Cullen
- Translational Biology, Biogen, Cambridge, MA, United States
| | | | - Katelin A Ennis
- Genetic and Neurodevelopmental Disorders, Biogen, Cambridge, MA, United States
| | - Mei Liu
- Biogen Postdoctoral Scientist Program, Biogen, Cambridge, MA, United States
| | - Chao Sun
- Biogen Postdoctoral Scientist Program, Biogen, Cambridge, MA, United States
| | - Normand E Allaire
- Biogen Postdoctoral Scientist Program, Biogen, Cambridge, MA, United States
| | - Marianna Foos
- Biogen Postdoctoral Scientist Program, Biogen, Cambridge, MA, United States
| | - Hui-Hsin Tsai
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
| | | | - Richard M Ransohoff
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
| | - Cherie Butts
- Digital & Quantitative Medicine, Biogen, Cambridge, MA, United States
| | - Michael Mingueneau
- Multiple Sclerosis and Neuroimmunology Research Unit, Biogen, Cambridge, MA, United States
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9
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Onodera J, Nagata H, Nakashima A, Ikegaya Y, Koyama R. Neuronal brain-derived neurotrophic factor manipulates microglial dynamics. Glia 2020; 69:890-904. [PMID: 33119934 DOI: 10.1002/glia.23934] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 10/22/2020] [Accepted: 10/22/2020] [Indexed: 12/19/2022]
Abstract
Brain-derived neurotrophic factor (BDNF), a main member of the neurotrophin family that is active in the brain, supports neuronal survival and growth. Microglial BDNF affects both the structural and functional properties of neurons. In contrast, whether and how neuronal BDNF affects microglial dynamics remain largely undetermined. Here, we examined the effects of BDNF on the properties of microglia in the CA3 region of the hippocampus. We chose this site because the axonal boutons of hippocampal mossy fibers, which are mostly formed in the CA3 region, contain the highest levels of BDNF in the rodent brain. We transfected mouse dentate granule cells with an adeno-associated virus that encodes both a BDNF short hairpin RNA (shRNA) and red fluorescent protein to examine the effects of mossy fiber-derived BDNF on microglia. Based on immunohistochemistry, BDNF knockdown with an shRNA resulted in an increase in microglial density in the mossy fiber pathway and increased engulfment of mossy fiber axons by microglia. In addition, we performed time-lapse imaging of microglial processes in hippocampal slice cultures to examine the effects of BDNF on microglial motility. Time-lapse imaging revealed increases in the motility of microglial processes and the engulfment of mossy fiber synapses by microglia when BDNF signaling was pharmacologically blocked. Thus, neuronal BDNF prevents microglia from engulfing mossy fiber synapses in the hippocampus.
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Affiliation(s)
- Junya Onodera
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hidetaka Nagata
- Platform Technology Research Unit, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Ai Nakashima
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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10
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Hoyle C, Redondo-Castro E, Cook J, Tzeng TC, Allan SM, Brough D, Lemarchand E. Hallmarks of NLRP3 inflammasome activation are observed in organotypic hippocampal slice culture. Immunology 2020; 161:39-52. [PMID: 32445196 PMCID: PMC7450173 DOI: 10.1111/imm.13221] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/05/2020] [Accepted: 05/18/2020] [Indexed: 12/16/2022] Open
Abstract
Microglial inflammation driven by the NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome contributes to brain disease and is a therapeutic target. Most mechanistic studies on NLRP3 activation use two-dimensional pure microglial cell culture systems. Here we studied the activation of the NLRP3 inflammasome in organotypic hippocampal slices, which allowed us to investigate microglial NLRP3 activation in a three-dimensional, complex tissue architecture. Toll-like receptor 2 and 4 activation primed microglial inflammasome responses in hippocampal slices by increasing NLRP3 and interleukin-1β expression. Nigericin-induced NLRP3 inflammasome activation was dynamically visualized in microglia through ASC speck formation. Downstream caspase-1 activation, gasdermin D cleavage, pyroptotic cell death and interleukin-1β release were also detected, and these findings were consistent when using different NLRP3 stimuli such as ATP and imiquimod. NLRP3 inflammasome pathway inhibitors were effective in organotypic hippocampal slices. Hence, we have highlighted organotypic hippocampal slice culture as a valuable ex vivo tool to allow the future study of NLRP3 inflammasomes in a representative tissue section, aiding the discovery of further mechanistic insights and drug development.
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Affiliation(s)
- Christopher Hoyle
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
| | - Elena Redondo-Castro
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
| | - James Cook
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
| | - Te-Chen Tzeng
- Immunology and Inflammation, Bristol-Myers Squibb (Celgene Corporation), Cambridge, MA, USA
| | - Stuart M Allan
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
| | - David Brough
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
| | - Eloise Lemarchand
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,The Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK
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11
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Doǧan E, Aygün H, Arslan G, Rzayev E, Avcı B, Ayyıldız M, Ağar E. The Role of NMDA Receptors in the Effect of Purinergic P2X7 Receptor on Spontaneous Seizure Activity in WAG/Rij Rats With Genetic Absence Epilepsy. Front Neurosci 2020; 14:414. [PMID: 32435183 PMCID: PMC7218146 DOI: 10.3389/fnins.2020.00414] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022] Open
Abstract
P2X7 receptors (P2X7Rs) are ATP sensitive cation channels and have been shown to be effective in various epilepsy models. Absence epilepsy is a type of idiopathic, generalized, non-convulsive epilepsy. Limited data exist on the role of P2X7Rs and no data has been reported regarding the interaction between P2X7Rs and glutamate receptor NMDA in absence epilepsy. Thus, this study was designed to investigate the role of P2X7 and NMDA receptors and their possible interaction in WAG/Rij rats with absence epilepsy. Permanent cannula and electrodes were placed on the skulls of the animals. After the healing period of the electrode and cannula implantation, ECoG recordings were obtained during 180 min before and after drug injections. P2X7R agonist BzATP, at doses of 50 μg and 100 μg (intracerebroventricular; i.c.v.) and antagonist A-438079, at doses of 20 μg and 40 μg (i.c.v.) were administered alone or prior to memantine (5 mg/kg, intraperitoneal; i.p.) injection. The total number (in every 20 min), the mean duration, and the amplitude of spike-wave discharges (SWDs) were calculated and compared. Rats were decapitated and the right and left hemisphere, cerebellum, and brainstem were separated for the measurements of the advanced oxidation protein product (AOPP), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), glutathione peroxide (GPx), and glutathione reductase (GR). BzATP and A-438079 did not alter measured SWDs parameters, whereas memantine reduced them, which is considered anticonvulsant. BzATP did not alter the anticonvulsant effect of memantine, while A-438079 decreased the effect of memantine. Administration of BzATP increased the levels of SOD and GR in cerebrum hemispheres. A-438079 did not alter any of the biochemical parameters. Memantine reduced the levels of MDA, GSH, and GR while increased the level of CAT in the cerebrum. Administration of BzATP before memantine abolished the effect of memantine on MDA levels. The evidence from this study suggests that P2X7Rs does not directly play a role in the formation of absence seizures. P2X7Rs agonist, reduced the antioxidant activity of memantine whereas agonist of P2X7Rs reduced the anticonvulsant action of memantine, suggesting a partial interaction between P2X7 and NMDA receptors in absence epilepsy model.
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Affiliation(s)
- Elif Doǧan
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Hatice Aygün
- Department of Physiology, Faculty of Medicine, Gaziosmanpasa University, Tokat, Turkey
| | - Gökhan Arslan
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Emil Rzayev
- Department of Clinical Biochemistry, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Bahattin Avcı
- Department of Clinical Biochemistry, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Mustafa Ayyıldız
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
| | - Erdal Ağar
- Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey
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12
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Sabogal-Guáqueta AM, Marmolejo-Garza A, de Pádua VP, Eggen B, Boddeke E, Dolga AM. Microglia alterations in neurodegenerative diseases and their modeling with human induced pluripotent stem cell and other platforms. Prog Neurobiol 2020; 190:101805. [PMID: 32335273 DOI: 10.1016/j.pneurobio.2020.101805] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/16/2020] [Accepted: 04/09/2020] [Indexed: 12/13/2022]
Abstract
Microglia are the main innate immune cells of the central nervous system (CNS). Unlike neurons and glial cells, which derive from ectoderm, microglia migrate early during embryo development from the yolk-sac, a mesodermal-derived structure. Microglia regulate synaptic pruning during development and induce or modulate inflammation during aging and chronic diseases. Microglia are sensitive to brain injuries and threats, altering their phenotype and function to adopt a so-called immune-activated state in response to any perceived threat to the CNS integrity. Here, we present a short overview on the role of microglia in human neurodegenerative diseases and provide an update on the current model systems to study microglia, including cell lines, iPSC-derived microglia with an emphasis in their transcriptomic profile and integration into 3D brain organoids. We present various strategies to model and study their role in neurodegeneration providing a relevant platform for the development of novel and more effective therapies.
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Affiliation(s)
- Angélica María Sabogal-Guáqueta
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioral and Cognitive Neurosciences (BCN), University of Groningen, Groningen, The Netherlands; Department of Biomedical Sciences of Cells & Systems, section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area-School of Medicine, SIU, University of Antioquia, Medellín, Colombia
| | - Alejandro Marmolejo-Garza
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioral and Cognitive Neurosciences (BCN), University of Groningen, Groningen, The Netherlands; Department of Biomedical Sciences of Cells & Systems, section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Vítor Passos de Pádua
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioral and Cognitive Neurosciences (BCN), University of Groningen, Groningen, The Netherlands; Neurology Department, Medical School, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Bart Eggen
- Department of Biomedical Sciences of Cells & Systems, section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Erik Boddeke
- Department of Biomedical Sciences of Cells & Systems, section Molecular Neurobiology, Faculty of Medical Sciences, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Amalia M Dolga
- Department of Molecular Pharmacology, Faculty of Science and Engineering, Groningen Research Institute of Pharmacy, Behavioral and Cognitive Neurosciences (BCN), University of Groningen, Groningen, The Netherlands.
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13
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Coleman LG, Zou J, Crews FT. Microglial depletion and repopulation in brain slice culture normalizes sensitized proinflammatory signaling. J Neuroinflammation 2020; 17:27. [PMID: 31954398 PMCID: PMC6969463 DOI: 10.1186/s12974-019-1678-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/16/2019] [Indexed: 12/20/2022] Open
Abstract
Background Microglia are critical mediators of neuroimmune pathology across multiple neurologic disorders. Microglia can be persistently activated or “primed” by Toll-like receptor (TLR) activation, ethanol, stress, and other insults. Thus, strategies to prevent or reverse microglial priming may be beneficial for conditions that involve progressively increasing microglial activation. Microglial depletion with repopulation is emerging as a potential therapy to normalize chronic immune activation. Primary organotypic hippocampal slice culture (OHSC) allows for the study of neuroimmune activation as well as microglial depletion and repopulation without involvement of peripheral immune activation. OHSC undergoes functional maturation and retains cytoarchitecture similar to in vivo. Methods OHSC underwent microglial depletion with the CSF1R antagonist PLX3397 with or without repopulation after removal of PLX3397. Immune, trophic, and synaptic gene changes in response to agonists of TLRs 2, 3, 4, 7, and 9 as well as ethanol were assessed in the settings of microglial depletion and repopulation. Gi-DREADD inhibition of microglia was used to confirm select findings seen with depletion. The ability of microglial repopulation to prevent progressive proinflammatory gene induction by chronic ethanol was also investigated. Results Microglia were depleted (> 90%) by PLX3397 in OHSC. Microglial depletion blunted proinflammatory responses to several TLR agonists as well as ethanol, which was mimicked by Gi-DREADD inhibition of OHSC microglia. Removal of PLX3397 was followed by complete repopulation of microglia. OHSCs with repopulated microglia showed increased baseline expression of anti-inflammatory cytokines (e.g., IL-10), microglial inhibitory signals (e.g., CX3CL1), and growth factors (e.g., BDNF). This was associated with blunted induction (~ 50%) of TNFα and IL-1β in response to agonists to TLR4 and TLR7. Further, chronic cycled ethanol from 4 days in vitro (DIV) to 16DIV caused immediate 2-fold inductions of TNFα and IL-1β that grew to ~4-fold of age-matched control slices by 40DIV. This persistent inflammatory gene expression was completely reversed by microglial depletion and repopulation after chronic ethanol. Conclusions Microglia in OHSCs mediate proinflammatory responses to TLR agonists and ethanol. Microglial repopulation promoted an anti-inflammatory, trophic neuroenvironment and normalized proinflammatory gene expression. This supports the possibility of microglial depletion with repopulation as a strategy to reverse chronic neuroimmune activation.
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Affiliation(s)
- Leon G Coleman
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, CB#7178, 1021 Thurston-Bowles Building, Chapel Hill, NC, USA. .,Department of Pharmacology, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, Chapel Hill, NC, USA.
| | - Jian Zou
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, CB#7178, 1021 Thurston-Bowles Building, Chapel Hill, NC, USA
| | - Fulton T Crews
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, School of Medicine, CB#7178, 1021 Thurston-Bowles Building, Chapel Hill, NC, USA.,Department of Pharmacology, The University of North Carolina at Chapel Hill, School of Medicine, Chapel Hill, Chapel Hill, NC, USA.,Department of Psychiatry, The University of North Carolina School of Medicine, Chapel Hill, Chapel Hill, NC, USA
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14
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Quarta A, Le Blon D, D'aes T, Pieters Z, Hamzei Taj S, Miró-Mur F, Luyckx E, Van Breedam E, Daans J, Goossens H, Dewilde S, Hens N, Pasque V, Planas AM, Hoehn M, Berneman Z, Ponsaerts P. Murine iPSC-derived microglia and macrophage cell culture models recapitulate distinct phenotypical and functional properties of classical and alternative neuro-immune polarisation. Brain Behav Immun 2019; 82:406-421. [PMID: 31525508 DOI: 10.1016/j.bbi.2019.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/05/2019] [Accepted: 09/12/2019] [Indexed: 12/24/2022] Open
Abstract
The establishment and validation of reliable induced pluripotent stem cell (iPSC)-derived in vitro models to study microglia and monocyte/macrophage immune function holds great potential for fundamental and translational neuro-immunology research. In this study, we first demonstrate that ramified CX3CR1+ iPSC-microglia (cultured within a neural environment) and round-shaped CX3CR1- iPSC-macrophages can easily be differentiated from newly established murine CX3CR1eGFP/+CCR2RFP/+ iPSC lines. Furthermore, we show that obtained murine iPSC-microglia and iPSC-macrophages are distinct cell populations, even though iPSC-macrophages may upregulate CX3CR1 expression when cultured within a neural environment. Next, we characterized the phenotypical and functional properties of murine iPSC-microglia and iPSC-macrophages following classical and alternative immune polarisation. While iPSC-macrophages could easily be triggered to adopt a classically-activated or alternatively-activated phenotype following, respectively, lipopolysaccharide + interferon γ or interleukin 13 (IL13) stimulation, iPSC-microglia and iPSC-macrophages cultured within a neural environment displayed a more moderate activation profile as characterised by the absence of MHCII expression upon classical immune polarisation and the absence of Ym1 expression upon alternative immune polarisation. Finally, extending our preceding in vivo studies, this striking phenotypical divergence was also observed for resident microglia and infiltrating monocytes within highly inflammatory cortical lesions in CX3CR1eGFP/+CCR2RFP/+ mice subjected to middle cerebral arterial occlusion (MCAO) stroke and following IL13-mediated therapeutic intervention thereon. In conclusion, our study demonstrates that the applied murine iPSC-microglia and iPSC-macrophage culture models are able to recapitulate in vivo microglia and monocyte/macrophage ontogeny and corresponding phenotypical/functional properties upon classical and alternative immune polarisation, and therefore represent a valuable in vitro platform to further study and modulate microglia and (infiltrating) monocyte immune responses under neuro-inflammatory conditions within a neural environment.
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Affiliation(s)
- Alessandra Quarta
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Debbie Le Blon
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Tine D'aes
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Zoë Pieters
- Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium; Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Belgium; Centre for Health Economics Research and Modelling Infectious Diseases, University of Antwerp, Belgium
| | - Somayyeh Hamzei Taj
- In-vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Francesc Miró-Mur
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Evi Luyckx
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium; Protein Chemistry, Proteomics and Epigenetic Signaling, University of Antwerp, Antwerp, Belgium
| | - Elise Van Breedam
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Jasmijn Daans
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Herman Goossens
- Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Sylvia Dewilde
- Protein Chemistry, Proteomics and Epigenetic Signaling, University of Antwerp, Antwerp, Belgium
| | - Niel Hens
- Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium; Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Hasselt University, Belgium; Centre for Health Economics Research and Modelling Infectious Diseases, University of Antwerp, Belgium
| | - Vincent Pasque
- Department of Development and Regeneration, Leuven Stem Cell Institute, Leuven Cancer Institute, KU Leuven - University of Leuven, Belgium
| | - Anna M Planas
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain; Department of Brain Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona (IIBB)-Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
| | - Mathias Hoehn
- In-vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Zwi Berneman
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, University of Antwerp, Antwerp, Belgium; Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium.
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15
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Replenishment of Organotypic Hippocampal Slice Cultures with Neonatal or Adult Microglia. Methods Mol Biol 2019. [PMID: 31392682 DOI: 10.1007/978-1-4939-9658-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
This protocol describes a method to deplete and repopulate organotypic hippocampal slice cultures with ramified microglia. We describe the slice culture preparation from newborn mice, standard culturing of neonatal microglia, and the acute isolation of microglia from adult mouse brain. Furthermore, we outline the technique for the replenishment of microglia-depleted slice cultures with different microglia populations and subsequent morphological analysis. We show that neonatal and adult microglia acquire specific ramified morphologies, which in case of adult microglia are indistinguishable from the in vivo situation. This procedure not only allows the functional investigation of microglia with different degrees of ramification but also enables the construction of chimeric slice cultures with respect to the microglia phenotype. Preparation of slice cultures can be completed in 3.5 h, preparation of mixed-glial cultures in 4 h, isolation of adult microglia can be accomplished in 3.5 h, and replenishment in 30 min.
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16
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Guttenplan KA, Liddelow SA. Astrocytes and microglia: Models and tools. J Exp Med 2018; 216:71-83. [PMID: 30541903 PMCID: PMC6314517 DOI: 10.1084/jem.20180200] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/16/2018] [Accepted: 11/26/2018] [Indexed: 01/05/2023] Open
Abstract
An amazing array of tools both old and new are available to investigate the function of astrocytes and microglia. Guttenplan and Liddelow discuss tools available to study the physiology and pathophysiology of these cells both in vivo and in culture systems. Glial cells serve as fundamental regulators of the central nervous system in development, homeostasis, and disease. Discoveries into the function of these cells have fueled excitement in glial research, with enthusiastic researchers addressing fundamental questions about glial biology and producing new scientific tools for the community. Here, we outline the pros and cons of in vivo and in vitro techniques to study astrocytes and microglia with the goal of helping researchers quickly identify the best approach for a given research question in the context of glial biology. It is truly a great time to be a glial biologist.
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Affiliation(s)
| | - Shane A Liddelow
- Neuroscience Institute, NYU Langone Medical Center, New York, NY.,Department of Neuroscience and Physiology, NYU Langone Medical Center, New York, NY.,Department of Pharmacology and Therapeutics, The University of Melbourne, Melbourne, Australia
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17
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Timmerman R, Burm SM, Bajramovic JJ. An Overview of in vitro Methods to Study Microglia. Front Cell Neurosci 2018; 12:242. [PMID: 30127723 PMCID: PMC6087748 DOI: 10.3389/fncel.2018.00242] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/18/2018] [Indexed: 12/11/2022] Open
Abstract
Neuroinflammation is a common feature in neurodegenerative diseases and strategies to modulate neuroinflammatory processes are increasingly considered as therapeutic options. In such strategies, glia cells rather than neurons represent the cellular targets. Microglia, the resident macrophages of the central nervous system, are principal players in neuroinflammation and detailed cellular biological knowledge of this particular cell type is therefore of pivotal importance. The last decade has shed new light on the origin, characteristics and functions of microglia, underlining the need for specific in vitro methodology to study these cells in detail. In this review we provide a comprehensive overview of existing methodology such as cell lines, stem cell-derived microglia and primary dissociated cell cultures, as well as discuss recent developments. As there is no in vitro method available yet that recapitulates all hallmarks of adult homeostatic microglia, we also discuss the advantages and limitations of existing models across different species.
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Affiliation(s)
- Raissa Timmerman
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, Netherlands
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18
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Eggen BJL, Boddeke EWGM, Kooistra SM. Regulation of Microglia Identity from an Epigenetic and Transcriptomic Point of View. Neuroscience 2017; 405:3-13. [PMID: 29247774 DOI: 10.1016/j.neuroscience.2017.12.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/11/2022]
Abstract
Microglia have long been recognized as the endogenous innate immune elements in the central nervous system (CNS) parenchyma. Besides fulfilling local immune-related functions, they provide cross-talk between the CNS and the immune system at large. In the adult CNS, microglia are involved in maintaining brain homeostasis, modulating synaptic transmission and clearance of apoptotic cells. During embryonic development, microglia are responsible for the removal of supernumerary synapses and neurons, and neuronal network formation. The full scale of their potential abilities has been highlighted by improvements in microglia isolation methods, the development of genetically tagged mouse models, advanced imaging technologies and the application of next-generation sequencing in recent years. Genome-wide expression analysis of relatively pure microglia populations from both mouse and human CNS tissues has thereby greatly contributed to our knowledge of their biology; what defines them under homeostatic conditions and how microglia respond to processes like aging and CNS disease? How and to what degree beneficial functions of microglia can be restored in the aged or diseased brain will be the key issue to be addressed in future research.
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Affiliation(s)
- Bart J L Eggen
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Erik W G M Boddeke
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Susanne M Kooistra
- Department of Neuroscience, Section Medical Physiology, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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19
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Yousif NM, de Oliveira ACP, Brioschi S, Huell M, Biber K, Fiebich BL. Activation of EP 2 receptor suppresses poly(I: C) and LPS-mediated inflammation in primary microglia and organotypic hippocampal slice cultures: Contributing role for MAPKs. Glia 2017; 66:708-724. [PMID: 29226424 DOI: 10.1002/glia.23276] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/08/2017] [Accepted: 11/17/2017] [Indexed: 12/26/2022]
Abstract
Brain inflammation is a critical factor involved in neurodegeneration. Recently, the prostaglandin E2 (PGE2 ) downstream members were suggested to modulate neuroinflammatory responses accompanying neurodegenerative diseases. In this study, we investigated the protective effects of prostaglandin E2 receptor 2 (EP2 ) during TLR3 and TLR4-driven inflammatory response using in vitro primary microglia and ex vivo organotypic hippocampal slice cultures (OHSCs). Depletion of microglia from OHSCs differentially affected TLR3 and TLR4 receptor expression. Poly(I:C) induced the production of prostaglandin E2 in OHSCs by increasing cyclooxygenase (COX-2) and microsomal prostaglandin E synthase (mPGES)-1. Besides, stimulation of OHSCs and microglia with Poly(I:C) upregulated EP2 receptor expression. Co-stimulation of OHSCs and microglia with the EP2 agonist butaprost reduced inflammatory mediators induced by LPS and Poly(I:C). In Poly(I:C) challenged OHSCs, butaprost almost restored microglia ramified morphology and reduced Iba1 immunoreactivity. Importantly, microglia depletion prevented the induction of inflammatory mediators following Poly(I:C) or LPS challenge in OHSCs. Activation of EP2 receptor reversed the Poly(I:C)/LPS-induced phosphorylation of the mitogen activated protein kinases (MAPKs) ERK, p38 MAPK and c-Jun N-terminal kinase (JNK) in microglia. Collectively, these data identify an anti-inflammatory function for EP2 signaling in diverse innate immune responses, through a mechanism that involves the mitogen-activated protein kinases pathway.
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Affiliation(s)
- Nizar M Yousif
- Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Simone Brioschi
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
| | - Michael Huell
- Zentrum für Psychiatrie Emmendingen, Neubronnstr. 25, Emmendingen, 79312
| | - Knut Biber
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
| | - Bernd L Fiebich
- Neurochemistry Research Group, Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstr. 5, Freiburg, D-79104, Germany
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20
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Bohlen CJ, Bennett FC, Tucker AF, Collins HY, Mulinyawe SB, Barres BA. Diverse Requirements for Microglial Survival, Specification, and Function Revealed by Defined-Medium Cultures. Neuron 2017; 94:759-773.e8. [PMID: 28521131 DOI: 10.1016/j.neuron.2017.04.043] [Citation(s) in RCA: 402] [Impact Index Per Article: 57.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 03/31/2017] [Accepted: 04/28/2017] [Indexed: 12/14/2022]
Abstract
Microglia, the resident macrophages of the CNS, engage in various CNS-specific functions that are critical for development and health. To better study microglia and the properties that distinguish them from other tissue macrophage populations, we have optimized serum-free culture conditions to permit robust survival of highly ramified adult microglia under defined-medium conditions. We find that astrocyte-derived factors prevent microglial death ex vivo and that this activity results from three primary components, CSF-1/IL-34, TGF-β2, and cholesterol. Using microglial cultures that have never been exposed to serum, we demonstrate a dramatic and lasting change in phagocytic capacity after serum exposure. Finally, we find that mature microglia rapidly lose signature gene expression after isolation, and that this loss can be reversed by engrafting cells back into an intact CNS environment. These data indicate that the specialized gene expression profile of mature microglia requires continuous instructive signaling from the intact CNS.
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Affiliation(s)
- Christopher J Bohlen
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - F Chris Bennett
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew F Tucker
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Hannah Y Collins
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sara B Mulinyawe
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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21
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Lin L, Desai R, Wang X, Lo EH, Xing C. Characteristics of primary rat microglia isolated from mixed cultures using two different methods. J Neuroinflammation 2017; 14:101. [PMID: 28482909 PMCID: PMC5422983 DOI: 10.1186/s12974-017-0877-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/01/2017] [Indexed: 12/11/2022] Open
Abstract
Background Microglial cultures comprise a critically important model system for investigating inflammatory mechanisms in almost all CNS disorders. Mild trypsinization and shaking are the two most commonly used methods to isolate primary microglia from mixed glial cultures. In this study, we characterized and compared microglia obtained using these two methods. Methods Primary rat microglia cultures were prepared from cerebral cortices of 1–2-day-old neonatal Sprague-Dawley rats. After achieving confluency at about 14 days in vitro, microglia were isolated from mixed glial cultures via either mild trypsinization or shaking. The purity of microglia was estimated by flow cytometry. Quantitative real-time PCR was used to measure mRNA expression. TNFα, IL-1β, IL-10, and IGF-1 in cell culture supernatant were measured using ELISA kits. Phagocytic function was assessed using fluorescein-labeled Escherichia coli K-12 BioParticles. Results Mild trypsinization generated a higher yield and purity than shaking. Microglia isolated by mild trypsinization appeared to be in a quiescent state with ramified morphology. Microglia isolated by shaking showed a more heterogenous morphology, including cells with rounded shapes suggestive of activation. Compared with shaking, microglia isolated by trypsinization also had lower baseline phenotype markers (iNOS, CD86, CD206, and arginase 1) and lower levels of cytokines (TNFα, IL-1β, IL-10, and IGF-1) as well as reduced phagocytic capability. Both methods yielded microglia that were responsive to various stimuli such as IL-4, lipopolysaccharide (LPS), or interferon-γ (IFNγ). Although stimulated patterns of gene expression and cytokine release were generally similar, there were also significant differences in terms of absolute response. LPS treatment induced significantly higher levels of TNFα and IL-10 in microglia isolated by mild trypsinization versus shaking. IFNγ induced a lower response in TNFα in microglia obtained by mild trypsinization versus shaking. Conclusions Our results suggest that isolating microglia with the shaking method may induce slight activation even at baseline, and this may affect stimulus responses in subsequent experiments. Caution and attention should be warranted when choosing isolation protocols for primary microglia cultures.
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Affiliation(s)
- Li Lin
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.,Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, MGH East 149-2401, Charlestown, MA, 02129, USA
| | - Rakhi Desai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, MGH East 149-2401, Charlestown, MA, 02129, USA
| | - Xiaoying Wang
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, MGH East 149-2401, Charlestown, MA, 02129, USA
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, MGH East 149-2401, Charlestown, MA, 02129, USA.
| | - Changhong Xing
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, MGH East 149-2401, Charlestown, MA, 02129, USA.
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22
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Bhatia HS, Roelofs N, Muñoz E, Fiebich BL. Alleviation of Microglial Activation Induced by p38 MAPK/MK2/PGE 2 Axis by Capsaicin: Potential Involvement of other than TRPV1 Mechanism/s. Sci Rep 2017; 7:116. [PMID: 28273917 PMCID: PMC5428011 DOI: 10.1038/s41598-017-00225-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/14/2017] [Indexed: 12/13/2022] Open
Abstract
Exaggerated inflammatory responses in microglia represent one of the major risk factors for various central nervous system’s (CNS) associated pathologies. Release of excessive inflammatory mediators such as prostaglandins and cytokines are the hallmark of hyper-activated microglia. Here we have investigated the hitherto unknown effects of capsaicin (cap) - a transient receptor potential vanilloid 1 (TRPV1) agonist- in murine primary microglia, organotypic hippocampal slice cultures (OHSCs) and human primary monocytes. Results demonstrate that cap (0.1–25 µM) significantly (p < 0.05) inhibited the release of prostaglandin E2 (PGE2), 8-iso-PGF2α, and differentially regulated the levels of cytokines (TNF-α, IL-6 & IL-1β). Pharmacological blockade (via capsazepine & SB366791) and genetic deficiency of TRPV1 (TRPV1−/−) did not prevent cap-mediated suppression of PGE2 in activated microglia and OHSCs. Inhibition of PGE2 was partially dependent on the reduced levels of PGE2 synthesising enzymes, COX-2 and mPGES-1. To evaluate potential molecular targets, we discovered that cap significantly suppressed the activation of p38 MAPK and MAPKAPK2 (MK2). Altogether, we demonstrate that cap alleviates excessive inflammatory events by targeting the PGE2 pathway in in vitro and ex vivo immune cell models. These findings have broad relevance in understanding and paving new avenues for ongoing TRPV1 based drug therapies in neuroinflammatory-associated diseases.
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Affiliation(s)
- Harsharan S Bhatia
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany. .,VivaCell Biotechnology GmbH, Ferdinand-Porsche-Strasse 5, D-79211, Denzlingen, Germany.
| | - Nora Roelofs
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany
| | - Eduardo Muñoz
- Maimonides Biomedical Research Institute of Córdoba, Reina Sofía University Hospital, Department of Cell Biology, Physiology and Immunology, University of Córdoba, Avda Menéndez Pidal s/n., 14004, Córdoba, Spain.,VivaCell Biotechnology España, Parque Científico Tecnológico Rabanales 21, 14014, Córdoba, Spain
| | - Bernd L Fiebich
- Department of Psychiatry and Psychotherapy, University of Freiburg Medical School, Hauptstrasse 5, D-79104, Freiburg, Germany.,VivaCell Biotechnology GmbH, Ferdinand-Porsche-Strasse 5, D-79211, Denzlingen, Germany
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23
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Sousa C, Biber K, Michelucci A. Cellular and Molecular Characterization of Microglia: A Unique Immune Cell Population. Front Immunol 2017; 8:198. [PMID: 28303137 PMCID: PMC5332364 DOI: 10.3389/fimmu.2017.00198] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/09/2017] [Indexed: 12/26/2022] Open
Abstract
Microglia are essential for the development and function of the adult brain. Microglia arise from erythro-myeloid precursors in the yolk sac and populate the brain rudiment early during development. Unlike monocytes that are constantly renewed from bone marrow hematopoietic stem cells throughout life, resident microglia in the healthy brain persist during adulthood via constant self-renewal. Their ontogeny, together with the absence of turnover from the periphery and the singular environment of the central nervous system, make microglia a unique cell population. Supporting this notion, recent genome-wide transcriptional studies revealed specific gene expression profiles clearly distinct from other brain and peripheral immune cells. Here, we highlight the breakthrough studies that, over the last decades, helped elucidate microglial cell identity, ontogeny, and function. We describe the main techniques that have been used for this task and outline the crucial milestones that have been achieved to reach our actual knowledge of microglia. Furthermore, we give an overview of the “microgliome” that is currently emerging thanks to the constant progress in the modern profiling techniques.
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Affiliation(s)
- Carole Sousa
- NORLUX Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg; Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Belval, Luxembourg
| | - Knut Biber
- Department of Psychiatry and Psychotherapy, Section Molecular Psychiatry, University of Freiburg, Freiburg, Germany; Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Alessandro Michelucci
- NORLUX Neuro-Oncology Laboratory, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg; Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-Belval, Luxembourg
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24
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Macht VA. Neuro-immune interactions across development: A look at glutamate in the prefrontal cortex. Neurosci Biobehav Rev 2016; 71:267-280. [PMID: 27593444 DOI: 10.1016/j.neubiorev.2016.08.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 07/26/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023]
Abstract
Although the primary role for the immune system is to respond to pathogens, more recently, the immune system has been demonstrated to have a critical role in signaling developmental events. Of particular interest for this review is how immunocompetent microglia and astrocytes interact with glutamatergic systems to influence the development of neural circuits in the prefrontal cortex (PFC). Microglia are the resident macrophages of the brain, and astrocytes mediate both glutamatergic uptake and coordinate with microglia to respond to the general excitatory state of the brain. Cross-talk between microglia, astrocytes, and glutamatergic neurons forms a quad-partite synapse, and this review argues that interactions within this synapse have critical implications for the maturation of PFC-dependent cognitive function. Similarly, understanding developmental shifts in immune signaling may help elucidate variations in sensitivities to developmental disruptions.
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Affiliation(s)
- Victoria A Macht
- University of South Carolina, 1512 Pendleton St., Department of Psychology, Columbia, SC 29208, United States.
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25
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Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal lobar dementia are among the most pressing problems of developed societies with aging populations. Neurons carry out essential functions such as signal transmission and network integration in the central nervous system and are the main targets of neurodegenerative disease. In this Review, I address how the neuron's environment also contributes to neurodegeneration. Maintaining an optimal milieu for neuronal function rests with supportive cells termed glia and the blood-brain barrier. Accumulating evidence suggests that neurodegeneration occurs in part because the environment is affected during disease in a cascade of processes collectively termed neuroinflammation. These observations indicate that therapies targeting glial cells might provide benefit for those afflicted by neurodegenerative disorders.
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