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Crews FT, Coleman LG, Macht VA, Vetreno RP. Alcohol, HMGB1, and Innate Immune Signaling in the Brain. Alcohol Res 2024; 44:04. [PMID: 39135668 PMCID: PMC11318841 DOI: 10.35946/arcr.v44.1.04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024] Open
Abstract
PURPOSE Binge drinking (i.e., consuming enough alcohol to achieve a blood ethanol concentration of 80 mg/dL, approximately 4-5 drinks within 2 hours), particularly in early adolescence, can promote progressive increases in alcohol drinking and alcohol-related problems that develop into compulsive use in the chronic relapsing disease, alcohol use disorder (AUD). Over the past decade, neuroimmune signaling has been discovered to contribute to alcohol-induced changes in drinking, mood, and neurodegeneration. This review presents a mechanistic hypothesis supporting high mobility group box protein 1 (HMGB1) and Toll-like receptor (TLR) signaling as key elements of alcohol-induced neuroimmune signaling across glia and neurons, which shifts gene transcription and synapses, altering neuronal networks that contribute to the development of AUD. This hypothesis may help guide further research on prevention and treatment. SEARCH METHODS The authors used the search terms "HMGB1 protein," "alcohol," and "brain" across PubMed, Scopus, and Embase to find articles published between 1991 and 2023. SEARCH RESULTS The database search found 54 references in PubMed, 47 in Scopus, and 105 in Embase. A total of about 100 articles were included. DISCUSSION AND CONCLUSIONS In the brain, immune signaling molecules play a role in normal development that differs from their functions in inflammation and the immune response, although cellular receptors and signaling are shared. In adults, pro-inflammatory signals have emerged as contributing to brain adaptation in stress, depression, AUD, and neurodegenerative diseases. HMGB1, a cytokine-like signaling protein released from activated cells, including neurons, is hypothesized to activate pro-inflammatory signals through TLRs that contribute to adaptations to binge and chronic heavy drinking. HMGB1 alone and in heteromers with other molecules activates TLRs and other immune receptors that spread signaling across neurons and glia. Both blood and brain levels of HMGB1 increase with ethanol exposure. In rats, an adolescent intermittent ethanol (AIE) binge drinking model persistently increases brain HMGB1 and its receptors; alters microglia, forebrain cholinergic neurons, and neuronal networks; and increases alcohol drinking and anxiety while disrupting cognition. Studies of human postmortem AUD brain have found elevated levels of HMGB1 and TLRs. These signals reduce cholinergic neurons, whereas microglia, the brain's immune cells, are activated by binge drinking. Microglia regulate synapses through complement proteins that can change networks affected by AIE that increase drinking, contributing to risks for AUD. Anti-inflammatory drugs, exercise, cholinesterase inhibitors, and histone deacetylase epigenetic inhibitors prevent and reverse the AIE-induced pathology. Further, HMGB1 antagonists and other anti-inflammatory treatments may provide new therapies for alcohol misuse and AUD. Collectively, these findings suggest that restoring the innate immune signaling balance is central to recovering from alcohol-related pathology.
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Affiliation(s)
- Fulton T. Crews
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Leon G. Coleman
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Victoria A. Macht
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Ryan P. Vetreno
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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2
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Zhao D, Hu M, Liu S. Glial cells in the mammalian olfactory bulb. Front Cell Neurosci 2024; 18:1426094. [PMID: 39081666 PMCID: PMC11286597 DOI: 10.3389/fncel.2024.1426094] [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: 04/30/2024] [Accepted: 06/24/2024] [Indexed: 08/02/2024] Open
Abstract
The mammalian olfactory bulb (OB), an essential part of the olfactory system, plays a critical role in odor detection and neural processing. Historically, research has predominantly focused on the neuronal components of the OB, often overlooking the vital contributions of glial cells. Recent advancements, however, underscore the significant roles that glial cells play within this intricate neural structure. This review discus the diverse functions and dynamics of glial cells in the mammalian OB, mainly focused on astrocytes, microglia, oligodendrocytes, olfactory ensheathing cells, and radial glia cells. Each type of glial contributes uniquely to the OB's functionality, influencing everything from synaptic modulation and neuronal survival to immune defense and axonal guidance. The review features their roles in maintaining neural health, their involvement in neurodegenerative diseases, and their potential in therapeutic applications for neuroregeneration. By providing a comprehensive overview of glial cell types, their mechanisms, and interactions within the OB, this article aims to enhance our understanding of the olfactory system's complexity and the pivotal roles glial cells play in both health and disease.
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Affiliation(s)
| | | | - Shaolin Liu
- Isakson Center for Neurological Disease Research, Department of Physiology and Pharmacology, Department of Biomedical Sciences, University of Georgia College of Veterinary Medicine, Athens, GA, United States
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Li H, Qian J, Wang Y, Wang J, Mi X, Qu L, Song N, Xie J. Potential convergence of olfactory dysfunction in Parkinson's disease and COVID-19: The role of neuroinflammation. Ageing Res Rev 2024; 97:102288. [PMID: 38580172 DOI: 10.1016/j.arr.2024.102288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/07/2024]
Abstract
Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects 7-10 million individuals worldwide. A common early symptom of PD is olfactory dysfunction (OD), and more than 90% of PD patients suffer from OD. Recent studies have highlighted a high incidence of OD in patients with SARS-CoV-2 infection. This review investigates the potential convergence of OD in PD and COVID-19, particularly focusing on the mechanisms by which neuroinflammation contributes to OD and neurological events. Starting from our fundamental understanding of the olfactory bulb, we summarize the clinical features of OD and pathological features of the olfactory bulb from clinical cases and autopsy reports in PD patients. We then examine SARS-CoV-2-induced olfactory bulb neuropathology and OD and emphasize the SARS-CoV-2-induced neuroinflammatory cascades potentially leading to PD manifestations. By activating microglia and astrocytes, as well as facilitating the aggregation of α-synuclein, SARS-CoV-2 could contribute to the onset or exacerbation of PD. We also discuss the possible contributions of NF-κB, the NLRP3 inflammasome, and the JAK/STAT, p38 MAPK, TLR4, IL-6/JAK2/STAT3 and cGAS-STING signaling pathways. Although olfactory dysfunction in patients with COVID-19 may be reversible, it is challenging to restore OD in patients with PD. With the emergence of new SARS-CoV-2 variants and the recurrence of infections, we call for continued attention to the intersection between PD and SARS-CoV-2 infection, especially from the perspective of OD.
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Affiliation(s)
- Hui Li
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Junliang Qian
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Youcui Wang
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Juan Wang
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Xiaoqing Mi
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Le Qu
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Ning Song
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.
| | - Junxia Xie
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.
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4
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Chagas LDS, Serfaty CA. The Influence of Microglia on Neuroplasticity and Long-Term Cognitive Sequelae in Long COVID: Impacts on Brain Development and Beyond. Int J Mol Sci 2024; 25:3819. [PMID: 38612629 PMCID: PMC11011312 DOI: 10.3390/ijms25073819] [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: 03/01/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Microglial cells, the immune cells of the central nervous system, are key elements regulating brain development and brain health. These cells are fully responsive to stressors, microenvironmental alterations and are actively involved in the construction of neural circuits in children and the ability to undergo full experience-dependent plasticity in adults. Since neuroinflammation is a known key element in the pathogenesis of COVID-19, one might expect the dysregulation of microglial function to severely impact both functional and structural plasticity, leading to the cognitive sequelae that appear in the pathogenesis of Long COVID. Therefore, understanding this complex scenario is mandatory for establishing the possible molecular mechanisms related to these symptoms. In the present review, we will discuss Long COVID and its association with reduced levels of BDNF, altered crosstalk between circulating immune cells and microglia, increased levels of inflammasomes, cytokines and chemokines, as well as the alterations in signaling pathways that impact neural synaptic remodeling and plasticity, such as fractalkines, the complement system, the expression of SIRPα and CD47 molecules and altered matrix remodeling. Together, these complex mechanisms may help us understand consequences of Long COVID for brain development and its association with altered brain plasticity, impacting learning disabilities, neurodevelopmental disorders, as well as cognitive decline in adults.
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Affiliation(s)
- Luana da Silva Chagas
- Program of Neuroscience, Department of Neurobiology, Institute of Biology, Federal Fluminense University, Niterói 24210-201, Rio de Janeiro, Brazil;
- National Institute of Science and Technology on Neuroimmunomodulation—INCT-NIM, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21041-250, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21041-250, Rio de Janeiro, Brazil
| | - Claudio Alberto Serfaty
- Program of Neuroscience, Department of Neurobiology, Institute of Biology, Federal Fluminense University, Niterói 24210-201, Rio de Janeiro, Brazil;
- National Institute of Science and Technology on Neuroimmunomodulation—INCT-NIM, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21041-250, Rio de Janeiro, Brazil
- Rio de Janeiro Research Network on Neuroinflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro 21041-250, Rio de Janeiro, Brazil
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5
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Wu J, Zhang J, Chen X, Wettschurack K, Que Z, Deming BA, Olivero-Acosta MI, Cui N, Eaton M, Zhao Y, Li SM, Suzuki M, Chen I, Xiao T, Halurkar MS, Mandal P, Yuan C, Xu R, Koss WA, Du D, Chen F, Wu LJ, Yang Y. Microglial over-pruning of synapses during development in autism-associated SCN2A-deficient mice and human cerebral organoids. Mol Psychiatry 2024:10.1038/s41380-024-02518-4. [PMID: 38499656 DOI: 10.1038/s41380-024-02518-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/20/2024]
Abstract
Autism spectrum disorder (ASD) is a major neurodevelopmental disorder affecting 1 in 36 children in the United States. While neurons have been the focus of understanding ASD, an altered neuro-immune response in the brain may be closely associated with ASD, and a neuro-immune interaction could play a role in the disease progression. As the resident immune cells of the brain, microglia regulate brain development and homeostasis via core functions including phagocytosis of synapses. While ASD has been traditionally considered a polygenic disorder, recent large-scale human genetic studies have identified SCN2A deficiency as a leading monogenic cause of ASD and intellectual disability. We generated a Scn2a-deficient mouse model, which displays major behavioral and neuronal phenotypes. However, the role of microglia in this disease model is unknown. Here, we reported that Scn2a-deficient mice have impaired learning and memory, accompanied by reduced synaptic transmission and lower spine density in neurons of the hippocampus. Microglia in Scn2a-deficient mice are partially activated, exerting excessive phagocytic pruning of post-synapses related to the complement C3 cascades during selective developmental stages. The ablation of microglia using PLX3397 partially restores synaptic transmission and spine density. To extend our findings from rodents to human cells, we established a microglia-incorporated human cerebral organoid model carrying an SCN2A protein-truncating mutation identified in children with ASD. We found that human microglia display increased elimination of post-synapse in cerebral organoids carrying the SCN2A mutation. Our study establishes a key role of microglia in multi-species autism-associated models of SCN2A deficiency from mouse to human cells.
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Affiliation(s)
- Jiaxiang Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Kyle Wettschurack
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Brody A Deming
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Maria I Olivero-Acosta
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Ningren Cui
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Yuanrui Zhao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Sophia M Li
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Matthew Suzuki
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Ian Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Tiange Xiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Manasi S Halurkar
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Purba Mandal
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Ranjie Xu
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Wendy A Koss
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA
| | - Dongshu Du
- School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Fuxue Chen
- School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, 47907, USA.
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, 47907, USA.
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6
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Durán Laforet V, Schafer DP. Microglia: Activity-dependent regulators of neural circuits. Ann N Y Acad Sci 2024; 1533:38-50. [PMID: 38294960 PMCID: PMC10976428 DOI: 10.1111/nyas.15105] [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] [Indexed: 02/02/2024]
Abstract
It has been more than a century since Pío del Río-Hortega first characterized microglia in histological stains of brain tissue. Since then, significant advances have been made in understanding the role of these resident central nervous system (CNS) macrophages. In particular, it is now known that microglia can sense neural activity and modulate neuronal circuits accordingly. We review the mechanisms by which microglia detect changes in neural activity to then modulate synapse numbers in the developing and mature CNS. This includes responses to both spontaneous and experience-driven neural activity. We further discuss activity-dependent mechanisms by which microglia regulate synaptic function and neural circuit excitability. Together, our discussion provides a comprehensive review of the activity-dependent functions of microglia within neural circuits in the healthy CNS, and highlights exciting new open questions related to understanding more fully microglia as key components and regulators of neural circuits.
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Affiliation(s)
- Violeta Durán Laforet
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Dorothy P Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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Weyer MP, Strehle J, Schäfer MKE, Tegeder I. Repurposing of pexidartinib for microglia depletion and renewal. Pharmacol Ther 2024; 253:108565. [PMID: 38052308 DOI: 10.1016/j.pharmthera.2023.108565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/07/2023]
Abstract
Pexidartinib (PLX3397) is a small molecule receptor tyrosine kinase inhibitor of colony stimulating factor 1 receptor (CSF1R) with moderate selectivity over other members of the platelet derived growth factor receptor family. It is approved for treatment of tenosynovial giant cell tumors (TGCT). CSF1R is highly expressed by microglia, which are macrophages of the central nervous system (CNS) that defend the CNS against injury and pathogens and contribute to synapse development and plasticity. Challenged by pathogens, apoptotic cells, debris, or inflammatory molecules they adopt a responsive state to propagate the inflammation and eventually return to a homeostatic state. The phenotypic switch may fail, and disease-associated microglia contribute to the pathophysiology in neurodegenerative or neuropsychiatric diseases or long-lasting detrimental brain inflammation after brain, spinal cord or nerve injury or ischemia/hemorrhage. Microglia also contribute to the growth permissive tumor microenvironment of glioblastoma (GBM). In rodents, continuous treatment for 1-2 weeks via pexidartinib food pellets leads to a depletion of microglia and subsequent repopulation from the remaining fraction, which is aided by peripheral monocytes that search empty niches for engraftment. The putative therapeutic benefit of such microglia depletion or forced renewal has been assessed in almost any rodent model of CNS disease or injury or GBM with heterogeneous outcomes, but a tendency of partial beneficial effects. So far, microglia monitoring e.g. via positron emission imaging is not standard of care for patients receiving Pexidartinib (e.g. for TGCT), so that the depletion and repopulation efficiency in humans is still largely unknown. Considering the virtuous functions of microglia, continuous depletion is likely no therapeutic option but short-lasting transient partial depletion to stimulate microglia renewal or replace microglia in genetic disease in combination with e.g. stem cell transplantation or as part of a multimodal concept in treatment of glioblastoma appears feasible. The present review provides an overview of the preclinical evidence pro and contra microglia depletion as a therapeutic approach.
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Affiliation(s)
- Marc-Philipp Weyer
- Institute of Clinical Pharmacology, Goethe-University Frankfurt, Faculty of Medicine, Frankfurt, Germany
| | - Jenny Strehle
- Department of Anesthesiology, University Medical Center Johannes Gutenberg-University Mainz, Germany
| | - Michael K E Schäfer
- Department of Anesthesiology, University Medical Center Johannes Gutenberg-University Mainz, Germany
| | - Irmgard Tegeder
- Institute of Clinical Pharmacology, Goethe-University Frankfurt, Faculty of Medicine, Frankfurt, Germany.
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Vecchiarelli HA, Lopes LT, Paolicelli RC, Stevens B, Wake H, Tremblay MÈ. Synapse Regulation. ADVANCES IN NEUROBIOLOGY 2024; 37:179-208. [PMID: 39207693 DOI: 10.1007/978-3-031-55529-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Microglia are the resident immune cells of the brain. As such, they rapidly detect changes in normal brain homeostasis and accurately respond by fine-tuning in a tightly regulated manner their morphology, gene expression, and functional behavior. Depending on the nature of these changes, microglia can thicken and retract their processes, proliferate and migrate, release numerous signaling factors and compounds influencing neuronal physiology (e.g., cytokines and trophic factors), in addition to secreting proteases able to transform the extracellular matrix, and phagocytosing various types of cellular debris, etc. Because microglia also transform rapidly (on a time scale of minutes) during experimental procedures, studying these very special cells requires methods that are specifically non-invasive. The development of such methods has provided unprecedented insights into the roles of microglia during normal physiological conditions. In particular, transcranial two-photon in vivo imaging revealed that presumably "resting" microglia continuously survey the brain parenchyma with their highly motile processes, in addition to modulating their structural and functional interactions with neuronal circuits along the changes in neuronal activity and behavioral experience occurring throughout the lifespan. In this chapter, we will describe how surveillant microglia interact with synaptic elements and modulate the number, maturation, function, and plasticity of synapses in the healthy developing, mature, and aging brain, with consequences on neuronal activity, learning and memory, and the behavioral outcome.
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Affiliation(s)
| | | | - Rosa C Paolicelli
- Division of Psychiatry Research, University of Zurich, Schlieren, Switzerland
| | - Beth Stevens
- Department of Neurology, Harvard Medical School, Center for Life Science, Boston Children's Hospital, F.M. Kirby Neurobiology Center, Boston, MA, USA
| | - Hiroaki Wake
- Division of Brain Circuits, National Institute for Basic Biology, Myodaiji-cho, Okazaki, Japan
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
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9
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Wallace JL, Pollen AA. Human neuronal maturation comes of age: cellular mechanisms and species differences. Nat Rev Neurosci 2024; 25:7-29. [PMID: 37996703 DOI: 10.1038/s41583-023-00760-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2023] [Indexed: 11/25/2023]
Abstract
The delayed and prolonged postmitotic maturation of human neurons, compared with neurons from other species, may contribute to human-specific cognitive abilities and neurological disorders. Here we review the mechanisms of neuronal maturation, applying lessons from model systems to understand the specific features of protracted human cortical maturation and species differences. We cover cell-intrinsic features of neuronal maturation, including transcriptional, epigenetic and metabolic mechanisms, as well as cell-extrinsic features, including the roles of activity and synapses, the actions of glial cells and the contribution of the extracellular matrix. We discuss evidence for species differences in biochemical reaction rates, the proposed existence of an epigenetic maturation clock and the contributions of both general and modular mechanisms to species-specific maturation timing. Finally, we suggest approaches to measure, improve and accelerate the maturation of human neurons in culture, examine crosstalk and interactions among these different aspects of maturation and propose conceptual models to guide future studies.
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Affiliation(s)
- Jenelle L Wallace
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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10
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Dye CN, Franceschelli D, Leuner B, Lenz KM. Microglia depletion facilitates the display of maternal behavior and alters activation of the maternal brain network in nulliparous female rats. Neuropsychopharmacology 2023; 48:1869-1877. [PMID: 37330580 PMCID: PMC10584962 DOI: 10.1038/s41386-023-01624-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/17/2023] [Accepted: 05/29/2023] [Indexed: 06/19/2023]
Abstract
The peripartum period is accompanied by peripheral immune alterations to promote a successful pregnancy. We and others have also demonstrated significant neuroimmune changes that emerge during late pregnancy and persist postpartum, most prominently decreased microglia numbers within limbic brain regions. Here we hypothesized that microglial downregulation is important for the onset and display of maternal behavior. To test this, we recapitulated the peripartum neuroimmune profile by depleting microglia in non-mother (i.e., nulliparous) female rats who are typically not maternal but can be induced to behave maternally towards foster pups after repeated exposure, a process called maternal sensitization. BLZ945, a selective colony-stimulating factor 1 receptor (CSF1R) inhibitor, was administered systemically to nulliparous rats, which led to ~75% decrease in microglia number. BLZ- and vehicle-treated females then underwent maternal sensitization and tissue was stained for ∆fosB to examine activation across maternally relevant brain regions. We found BLZ-treated females with microglial depletion met criteria for displaying maternal behavior significantly sooner than vehicle-treated females and displayed increased pup-directed behaviors. Microglia depletion also reduced threat appraisal behavior in an open field test. Notably, nulliparous females with microglial depletion had decreased numbers of ∆fosB+ cells in the medial amygdala and periaqueductal gray, and increased numbers in the prefrontal cortex and somatosensory cortex, compared to vehicle. Our results demonstrate that microglia regulate maternal behavior in adult females, possibly by shifting patterns of activity in the maternal brain network.
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Affiliation(s)
- Courtney N Dye
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH, USA
| | | | - Benedetta Leuner
- Department of Psychology, The Ohio State University, Columbus, OH, USA
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Kathryn M Lenz
- Department of Psychology, The Ohio State University, Columbus, OH, USA.
- Department of Neuroscience, The Ohio State University, Columbus, OH, USA.
- Institute of Behavioral Medicine Research, The Ohio State University, Columbus, OH, USA.
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Niiyama T, Fujimoto S, Imai T. Microglia Are Dispensable for Developmental Dendrite Pruning of Mitral Cells in Mice. eNeuro 2023; 10:ENEURO.0323-23.2023. [PMID: 37890992 PMCID: PMC10644373 DOI: 10.1523/eneuro.0323-23.2023] [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: 08/26/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 10/29/2023] Open
Abstract
During early development, neurons in the brain often form excess synaptic connections. Later, they strengthen some connections while eliminating others to build functional neuronal circuits. In the olfactory bulb, a mitral cell initially extends multiple dendrites to multiple glomeruli but eventually forms a single primary dendrite through the activity-dependent dendrite pruning process. Recent studies have reported that microglia facilitate synapse pruning during the circuit remodeling in some systems. It has remained unclear whether microglia are involved in the activity-dependent dendrite pruning in the developing brains. Here, we examined whether microglia are required for the developmental dendrite pruning of mitral cells in mice. To deplete microglia in the fetal brain, we treated mice with a colony-stimulating factor 1 receptor (CSF1R) inhibitor, PLX5622, from pregnancy. Microglia were reduced by >90% in mice treated with PLX5622. However, dendrite pruning of mitral cells was not significantly affected. Moreover, we found no significant differences in the number, density, and size of excitatory synapses formed in mitral cell dendrites. We also found no evidence for the role of microglia in the activity-dependent dendrite remodeling of layer 4 (L4) neurons in the barrel cortex. In contrast, the density of excitatory synapses (dendritic spines) in granule cells in the olfactory bulb was significantly increased in mice treated with PLX5622 at postnatal day (P) 6, suggesting a role for the regulation of dendritic spines. Our results indicate that microglia do not play a critical role in activity-dependent dendrite pruning at the neurite level during early postnatal development in mice.
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Affiliation(s)
- Tetsushi Niiyama
- Graduate School of Medical Sciences, Kyushu University, 812-8582, Fukuoka, Japan
| | - Satoshi Fujimoto
- Graduate School of Medical Sciences, Kyushu University, 812-8582, Fukuoka, Japan
| | - Takeshi Imai
- Graduate School of Medical Sciences, Kyushu University, 812-8582, Fukuoka, Japan
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12
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Whitelaw BS, Stoessel MB, Majewska AK. Movers and shakers: Microglial dynamics and modulation of neural networks. Glia 2023; 71:1575-1591. [PMID: 36533844 PMCID: PMC10729610 DOI: 10.1002/glia.24323] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Microglia are multifaceted cells that act as immune sentinels, with important roles in pathological events, but also as integral contributors to the normal development and function of neural circuits. In the last decade, our understanding of the contributions these cells make to synaptic health and dysfunction has expanded at a dizzying pace. Here we review the known mechanisms that govern the dynamics of microglia allowing these motile cells to interact with synapses, and recruit microglia to specific sites on neurons. We then review the molecular signals that may underlie the function of microglia in synaptic remodeling. The emerging picture from the literature suggests that microglia are highly sensitive cells, reacting to neuronal signals with dynamic and specific actions tuned to the need of specific synapses and networks.
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Affiliation(s)
- Brendan Steven Whitelaw
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
| | - Mark Blohm Stoessel
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
| | - Ania Katarzyna Majewska
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
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13
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Koss KM, Son T, Li C, Hao Y, Cao J, Churchward MA, Zhang ZJ, Wertheim JA, Derda R, Todd KG. Toward discovering a novel family of peptides targeting neuroinflammatory states of brain microglia and astrocytes. J Neurochem 2023:10.1111/jnc.15840. [PMID: 37171455 PMCID: PMC10640667 DOI: 10.1111/jnc.15840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023]
Abstract
Microglia are immune-derived cells critical to the development and healthy function of the brain and spinal cord, yet are implicated in the active pathology of many neuropsychiatric disorders. A range of functional phenotypes associated with the healthy brain or disease states has been suggested from in vivo work and were modeled in vitro as surveying, reactive, and primed sub-types of primary rat microglia and mixed microglia/astrocytes. It was hypothesized that the biomolecular profile of these cells undergoes a phenotypical change as well, and these functional phenotypes were explored for potential novel peptide binders using a custom 7 amino acid-presenting M13 phage library (SX7) to identify unique peptides that bind differentially to these respective cell types. Surveying glia were untreated, reactive were induced with a lipopolysaccharide treatment, recovery was modeled with a potent anti-inflammatory treatment dexamethasone, and priming was determined by subsequently challenging the cells with interferon gamma. Microglial function was profiled by determining the secretion of cytokines and nitric oxide, and expression of inducible nitric oxide synthase. After incubation with the SX7 phage library, populations of SX7-positive microglia and/or astrocytes were collected using fluorescence-activated cell sorting, SX7 phage was amplified in Escherichia coli culture, and phage DNA was sequenced via next-generation sequencing. Binding validation was done with synthesized peptides via in-cell westerns. Fifty-eight unique peptides were discovered, and their potential functions were assessed using a basic local alignment search tool. Peptides potentially originated from proteins ranging in function from a variety of supportive glial roles, including synapse support and pruning, to inflammatory incitement including cytokine and interleukin activation, and potential regulation in neurodegenerative and neuropsychiatric disorders.
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Affiliation(s)
- K M Koss
- Comprehensive Transplant Center and Department of Surgery, Feinberg School of Medicine, Northwestern University, Illinois, Chicago, USA
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Alberta, Edmonton, Canada
- Department of Surgery, University of Arizona College of Medicine, Arizona, Tucson, USA
| | - T Son
- Comprehensive Transplant Center and Department of Surgery, Feinberg School of Medicine, Northwestern University, Illinois, Chicago, USA
| | - C Li
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr NW, Edmonton, AB T6G 2G2, Canada
| | - Y Hao
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr NW, Edmonton, AB T6G 2G2, Canada
| | - J Cao
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr NW, Edmonton, AB T6G 2G2, Canada
- 48Hour Discovery Inc, 11421 Saskatchewan Dr NW, Edmonton, AB T6G 2M9, Canada
| | - M A Churchward
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Alberta, Edmonton, Canada
- Department of Biology and Environmental Sciences, Concordia University of Edmonton, Alberta, Edmonton, Canada
| | - Z J Zhang
- Comprehensive Transplant Center and Department of Surgery, Feinberg School of Medicine, Northwestern University, Illinois, Chicago, USA
| | - J A Wertheim
- Comprehensive Transplant Center and Department of Surgery, Feinberg School of Medicine, Northwestern University, Illinois, Chicago, USA
- Department of Surgery, University of Arizona College of Medicine, Arizona, Tucson, USA
| | - R Derda
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr NW, Edmonton, AB T6G 2G2, Canada
- 48Hour Discovery Inc, 11421 Saskatchewan Dr NW, Edmonton, AB T6G 2M9, Canada
| | - K G Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Alberta, Edmonton, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Alberta, Edmonton, Canada
- Department of Biomedical Engineering, University of Alberta, Alberta, Edmonton, Canada
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14
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Machado da Silva MC, Iglesias LP, Candelario-Jalil E, Khoshbouei H, Moreira FA, de Oliveira ACP. Role of Microglia in Psychostimulant Addiction. Curr Neuropharmacol 2023; 21:235-259. [PMID: 36503452 PMCID: PMC10190137 DOI: 10.2174/1570159x21666221208142151] [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: 05/13/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 12/14/2022] Open
Abstract
The use of psychostimulant drugs can modify brain function by inducing changes in the reward system, mainly due to alterations in dopaminergic and glutamatergic transmissions in the mesocorticolimbic pathway. However, the etiopathogenesis of addiction is a much more complex process. Previous data have suggested that microglia and other immune cells are involved in events associated with neuroplasticity and memory, which are phenomena that also occur in addiction. Nevertheless, how dependent is the development of addiction on the activity of these cells? Although the mechanisms are not known, some pathways may be involved. Recent data have shown psychoactive substances may act directly on immune cells, alter their functions and induce various inflammatory mediators that modulate synaptic activity. These could, in turn, be involved in the pathological alterations that occur in substance use disorder. Here, we extensively review the studies demonstrating how cocaine and amphetamines modulate microglial number, morphology, and function. We also describe the effect of these substances in the production of inflammatory mediators and a possible involvement of some molecular signaling pathways, such as the toll-like receptor 4. Although the literature in this field is scarce, this review compiles the knowledge on the neuroimmune axis that is involved in the pathogenesis of addiction, and suggests some pharmacological targets for the development of pharmacotherapy.
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Affiliation(s)
- Maria Carolina Machado da Silva
- Department of Pharmacology, Neuropharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil;
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Lia Parada Iglesias
- Department of Pharmacology, Neuropsychopharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Habibeh Khoshbouei
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Fabrício Araujo Moreira
- Department of Pharmacology, Neuropsychopharmacology Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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15
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Basilico B, Ferrucci L, Khan A, Di Angelantonio S, Ragozzino D, Reverte I. What microglia depletion approaches tell us about the role of microglia on synaptic function and behavior. Front Cell Neurosci 2022; 16:1022431. [PMID: 36406752 PMCID: PMC9673171 DOI: 10.3389/fncel.2022.1022431] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Microglia are dynamic cells, constantly surveying their surroundings and interacting with neurons and synapses. Indeed, a wealth of knowledge has revealed a critical role of microglia in modulating synaptic transmission and plasticity in the developing brain. In the past decade, novel pharmacological and genetic strategies have allowed the acute removal of microglia, opening the possibility to explore and understand the role of microglia also in the adult brain. In this review, we summarized and discussed the contribution of microglia depletion strategies to the current understanding of the role of microglia on synaptic function, learning and memory, and behavior both in physiological and pathological conditions. We first described the available microglia depletion methods highlighting their main strengths and weaknesses. We then reviewed the impact of microglia depletion on structural and functional synaptic plasticity. Next, we focused our analysis on the effects of microglia depletion on behavior, including general locomotor activity, sensory perception, motor function, sociability, learning and memory both in healthy animals and animal models of disease. Finally, we integrated the findings from the reviewed studies and discussed the emerging roles of microglia on the maintenance of synaptic function, learning, memory strength and forgetfulness, and the implications of microglia depletion in models of brain disease.
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Affiliation(s)
| | - Laura Ferrucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Azka Khan
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Rome, Italy
| | - Davide Ragozzino
- Laboratory Affiliated to Institute Pasteur Italia – Fondazione Cenci Bolognetti, Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
- *Correspondence: Davide Ragozzino,
| | - Ingrid Reverte
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
- Ingrid Reverte,
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16
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Pekarek BT, Kochukov M, Lozzi B, Wu T, Hunt PJ, Tepe B, Hanson Moss E, Tantry EK, Swanson JL, Dooling SW, Patel M, Belfort BDW, Romero JM, Bao S, Hill MC, Arenkiel BR. Oxytocin signaling is necessary for synaptic maturation of adult-born neurons. Genes Dev 2022; 36:1100-1118. [PMID: 36617877 PMCID: PMC9851403 DOI: 10.1101/gad.349930.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 11/14/2022] [Indexed: 12/13/2022]
Abstract
Neural circuit plasticity and sensory response dynamics depend on forming new synaptic connections. Despite recent advances toward understanding the consequences of circuit plasticity, the mechanisms driving circuit plasticity are unknown. Adult-born neurons within the olfactory bulb have proven to be a powerful model for studying circuit plasticity, providing a broad and accessible avenue into neuron development, migration, and circuit integration. We and others have shown that efficient adult-born neuron circuit integration hinges on presynaptic activity in the form of diverse signaling peptides. Here, we demonstrate a novel oxytocin-dependent mechanism of adult-born neuron synaptic maturation and circuit integration. We reveal spatial and temporal enrichment of oxytocin receptor expression within adult-born neurons in the murine olfactory bulb, with oxytocin receptor expression peaking during activity-dependent integration. Using viral labeling, confocal microscopy, and cell type-specific RNA-seq, we demonstrate that oxytocin receptor signaling promotes synaptic maturation of newly integrating adult-born neurons by regulating their morphological development and expression of mature synaptic AMPARs and other structural proteins.
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Affiliation(s)
- Brandon T Pekarek
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Mikhail Kochukov
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Brittney Lozzi
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Timothy Wu
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Patrick J Hunt
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Burak Tepe
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Elizabeth Hanson Moss
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Evelyne K Tantry
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Jessica L Swanson
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Sean W Dooling
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Mayuri Patel
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
| | - Benjamin D W Belfort
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Juan M Romero
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Suyang Bao
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Matthew C Hill
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
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17
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Sonn I, Honda-Ozaki F, Yoshimatsu S, Morimoto S, Watanabe H, Okano H. Single transcription factor efficiently leads human induced pluripotent stem cells to functional microglia. Inflamm Regen 2022; 42:20. [PMID: 35773727 PMCID: PMC9248164 DOI: 10.1186/s41232-022-00201-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/22/2022] [Indexed: 12/30/2022] Open
Abstract
Background Microglia are innate immune cells that are the only residential macrophages in the central nervous system. They play vital physiological roles in the adult brain and during development. Microglia are particularly in the spotlight because many genetic risk factors recently identified for neurodegenerative diseases are largely expressed in microglia. Rare polymorphisms in these risk alleles lead to abnormal activity of microglia under traumatic or disease conditions. Methods In the present study, to investigate the multifaceted functions of human microglia, we established a novel robust protocol to generate microglia from human induced pluripotent stem cells (hiPSCs) using a combination of cytokines and small chemicals essential for microglia ontogeny. Moreover, we highly enhanced the microglial differentiation efficiency by forcing the expression of PU.1, a crucial transcription factor for microglial development, during posterior mesoderm differentiation. Results By our novel method, we demonstrated the generation of a greater number of hiPSC-derived microglia (hiMGLs, approximately 120-folds) than the prior methods (at most 40-folds). Over 90% of the hiMGLs expressed microglia-specific markers, such as CX3CR1 and IBA-1. Whole-transcriptome analysis revealed that these hiMGLs are similar to human primary microglia but differ from monocytes/macrophages. Furthermore, the specific physiological functions of microglia were confirmed through indices of lipopolysaccharide responsiveness, phagocytotic ability, and inflammasome formation. By co-culturing these hiMGLs with mouse primary neurons, we demonstrated that hiMGLs can regulate the activity and maturation of neurons. Conclusions In this study, our new simple, rapid, and highly efficient method for generating microglia from hiPSCs will prove useful for future investigations on microglia in both physiological and disease conditions, as well as for drug discovery. Supplementary Information The online version contains supplementary material available at 10.1186/s41232-022-00201-1.
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Affiliation(s)
- Iki Sonn
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan.,Research Fellow of Japan Society for the Promotion of Science (JSPS), Tokyo, 102-0083, Japan
| | - Fumiko Honda-Ozaki
- K Pharma, Inc., Fujisawa, Kanagawa, 251-8555, Japan.,Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Sho Yoshimatsu
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan.,Research Fellow of Japan Society for the Promotion of Science (JSPS), Tokyo, 102-0083, Japan
| | - Satoru Morimoto
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Hirotaka Watanabe
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, 160-8582, Japan.
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18
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Chithanathan K, Xuan FL, Hickey MA, Tian L. Enhanced Anxiety and Olfactory Microglial Activation in Early-Stage Familial Alzheimer's Disease Mouse Model. BIOLOGY 2022; 11:biology11060938. [PMID: 35741458 PMCID: PMC9219751 DOI: 10.3390/biology11060938] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/15/2022] [Accepted: 06/15/2022] [Indexed: 04/30/2023]
Abstract
Anxiety is a known comorbidity and risk factor for conversion to neuroinflammation-mediated dementia in patients with Alzheimer's disease (AD). Here, we investigated if anxiety occurred as an early endophenotype of mutant familial AD (5 × FAD) male mice and the underlying neuroinflammatory mechanisms. We observed that compared to wildtype (WT) littermates, 5 × FAD mice showed enhanced anxiety at as early as 2 months old (mo). Interestingly, these 5 × FAD male mice had concomitantly increased mRNA levels of pro-inflammatory cytokines such as interleukin 1 beta (Il1b) and tumor necrosis factor (Tnf) in the olfactory bulb (OB) but not the frontal cortex (FC). Increased expression of Tnf in the OB was significantly correlated with the anxious behavior in the FAD but not WT mice. Furthermore, we found more prominent microglial activation and morphological changes in the OB of 2 mo 5 × FAD mice, while only microglial ramification was seen in the FC. To understand if neuroinflammatory changes in the FC could occur at a later stage, we studied 5~6 mo male mice and found that Il1b, interleukin 18 (Il18), and Tnf were upregulated in the FC at this older age. Furthermore, we observed that numbers of microglia and macrophage as well as microglial synaptic pruning, as indicated by phagocytosis of presynaptic component of vesicular glutamate transporter-2, were increased in the OB but not the FC of 5~6 mo 5 × FAD mice. Our findings demonstrated the OB as a more sensitive brain region than the cerebral cortex for microglia-mediated neuroinflammation in association with anxiety in FAD mice and supported the notion that the OB can be an early-stage biomarker in AD.
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Affiliation(s)
- Keerthana Chithanathan
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
| | - Fang-Ling Xuan
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
| | - Miriam Ann Hickey
- Department of Pharmacology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia;
| | - Li Tian
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
- Correspondence:
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19
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Stables J, Green EK, Sehgal A, Patkar OL, Keshvari S, Taylor I, Ashcroft ME, Grabert K, Wollscheid-Lengeling E, Szymkowiak S, McColl BW, Adamson A, Humphreys NE, Mueller W, Starobova H, Vetter I, Shabestari SK, Blurton-Jones MM, Summers KM, Irvine KM, Pridans C, Hume DA. A kinase-dead Csf1r mutation associated with adult-onset leukoencephalopathy has a dominant inhibitory impact on CSF1R signalling. Development 2022; 149:274819. [PMID: 35333324 PMCID: PMC9002114 DOI: 10.1242/dev.200237] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 02/04/2022] [Indexed: 12/21/2022]
Abstract
Amino acid substitutions in the kinase domain of the human CSF1R gene are associated with autosomal dominant adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). To model the human disease, we created a disease-associated mutation (pGlu631Lys; E631K) in the mouse Csf1r locus. Homozygous mutation (Csf1rE631K/E631K) phenocopied the Csf1r knockout, with prenatal mortality or severe postnatal growth retardation and hydrocephalus. Heterozygous mutation delayed the postnatal expansion of tissue macrophage populations in most organs. Bone marrow cells from Csf1rE631K/+mice were resistant to CSF1 stimulation in vitro, and Csf1rE631K/+ mice were unresponsive to administration of a CSF1-Fc fusion protein, which expanded tissue macrophage populations in controls. In the brain, microglial cell numbers and dendritic arborisation were reduced in Csf1rE631K/+ mice, as in patients with ALSP. The microglial phenotype is the opposite of microgliosis observed in Csf1r+/- mice. However, we found no evidence of brain pathology or impacts on motor function in aged Csf1rE631K/+ mice. We conclude that heterozygous disease-associated CSF1R mutations compromise CSF1R signalling. We speculate that leukoencephalopathy associated with dominant human CSF1R mutations requires an environmental trigger and/or epistatic interaction with common neurodegenerative disease-associated alleles.
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Affiliation(s)
- Jennifer Stables
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Emma K Green
- Centre for Inflammation Research and Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Anuj Sehgal
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Omkar L Patkar
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Sahar Keshvari
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Isis Taylor
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Maisie E Ashcroft
- Centre for Inflammation Research and Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Kathleen Grabert
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm 171 77, Sweden
| | - Evi Wollscheid-Lengeling
- Luxembourg Centre for Systems Biomedicine, Université du Luxembourg, Belvaux, L-4401, Luxembourg
| | - Stefan Szymkowiak
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Barry W McColl
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Antony Adamson
- Genome Editing Unit, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Neil E Humphreys
- Genome Editing Unit, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Werner Mueller
- Genome Editing Unit, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Hana Starobova
- Institute for Molecular Biosciences & School of Pharmacy, University of Queensland, Brisbane, Qld 4072, Australia
| | - Irina Vetter
- Institute for Molecular Biosciences & School of Pharmacy, University of Queensland, Brisbane, Qld 4072, Australia
| | | | | | - Kim M Summers
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Katharine M Irvine
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
| | - Clare Pridans
- Centre for Inflammation Research and Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - David A Hume
- Mater Research Institute-University of Queensland, Translational Research Institute, Brisbane, Qld 4102, Australia
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20
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Kurematsu C, Sawada M, Ohmuraya M, Tanaka M, Kuboyama K, Ogino T, Matsumoto M, Oishi H, Inada H, Ishido Y, Sakakibara Y, Nguyen HB, Thai TQ, Kohsaka S, Ohno N, Yamada MK, Asai M, Sokabe M, Nabekura J, Asano K, Tanaka M, Sawamoto K. Synaptic pruning of murine adult-born neurons by microglia depends on phosphatidylserine. J Exp Med 2022; 219:213073. [PMID: 35297954 PMCID: PMC9195048 DOI: 10.1084/jem.20202304] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 08/13/2021] [Accepted: 11/30/2021] [Indexed: 12/21/2022] Open
Abstract
New neurons, continuously added in the adult olfactory bulb (OB) and hippocampus, are involved in information processing in neural circuits. Here, we show that synaptic pruning of adult-born neurons by microglia depends on phosphatidylserine (PS), whose exposure on dendritic spines is inversely correlated with their input activity. To study the role of PS in spine pruning by microglia in vivo, we developed an inducible transgenic mouse line, in which the exposed PS is masked by a dominant-negative form of milk fat globule-EGF-factor 8 (MFG-E8), MFG-E8D89E. In this transgenic mouse, the spine pruning of adult-born neurons by microglia is impaired in the OB and hippocampus. Furthermore, the electrophysiological properties of these adult-born neurons are altered in MFG-E8D89E mice. These data suggest that PS is involved in the microglial spine pruning and the functional maturation of adult-born neurons. The MFG-E8D89E-based genetic approach shown in this study has broad applications for understanding the biology of PS-mediated phagocytosis in vivo.
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Affiliation(s)
- Chihiro Kurematsu
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Masato Sawada
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Division of Neural Development and Regeneration, National Institute for Physiological Sciences, Okazaki, Japan
| | - Masaki Ohmuraya
- Department of Genetics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Motoki Tanaka
- Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Kazuya Kuboyama
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takashi Ogino
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mami Matsumoto
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Hisashi Oishi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroyuki Inada
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Yuri Ishido
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yukina Sakakibara
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Huy Bang Nguyen
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy, Faculty of Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Truc Quynh Thai
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Histology-Embryology-Genetics, Faculty of Basic Medical Sciences, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam
| | - Shinichi Kohsaka
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.,Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Maki K Yamada
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences and Institute of Neuroscience, Tokushima Bunri University, Sanuki, Japan
| | - Masato Asai
- Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Kenichi Asano
- Laboratory of Immune Regulation, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Masato Tanaka
- Laboratory of Immune Regulation, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Kazunobu Sawamoto
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Division of Neural Development and Regeneration, National Institute for Physiological Sciences, Okazaki, Japan
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21
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Han J, Chitu V, Stanley ER, Wszolek ZK, Karrenbauer VD, Harris RA. Inhibition of colony stimulating factor-1 receptor (CSF-1R) as a potential therapeutic strategy for neurodegenerative diseases: opportunities and challenges. Cell Mol Life Sci 2022; 79:219. [PMID: 35366105 PMCID: PMC8976111 DOI: 10.1007/s00018-022-04225-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/06/2022] [Accepted: 02/26/2022] [Indexed: 12/12/2022]
Abstract
Microglia are specialized dynamic immune cells in the central nervous system (CNS) that plays a crucial role in brain homeostasis and in disease states. Persistent neuroinflammation is considered a hallmark of many neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson's disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and primary progressive multiple sclerosis (MS). Colony stimulating factor 1-receptor (CSF-1R) is predominantly expressed on microglia and its expression is significantly increased in neurodegenerative diseases. Cumulative findings have indicated that CSF-1R inhibitors can have beneficial effects in preclinical neurodegenerative disease models. Research using CSF-1R inhibitors has now been extended into non-human primates and humans. This review article summarizes the most recent advances using CSF-1R inhibitors in different neurodegenerative conditions including AD, PD, HD, ALS and MS. Potential challenges for translating these findings into clinical practice are presented.
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Affiliation(s)
- Jinming Han
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461 USA
| | - E. Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461 USA
| | | | - Virginija Danylaité Karrenbauer
- Department of Clinical Neuroscience, Center for Molecular Medicine L8:04, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm, Sweden
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Robert A. Harris
- Applied Immunology and Immunotherapy, Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
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22
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Tufo C, Poopalasundaram S, Dorrego-Rivas A, Ford MC, Graham A, Grubb MS. Development of the mammalian main olfactory bulb. Development 2022; 149:274348. [PMID: 35147186 PMCID: PMC8918810 DOI: 10.1242/dev.200210] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The mammalian main olfactory bulb is a crucial processing centre for the sense of smell. The olfactory bulb forms early during development and is functional from birth. However, the olfactory system continues to mature and change throughout life as a target of constitutive adult neurogenesis. Our Review synthesises current knowledge of prenatal, postnatal and adult olfactory bulb development, focusing on the maturation, morphology, functions and interactions of its diverse constituent glutamatergic and GABAergic cell types. We highlight not only the great advances in the understanding of olfactory bulb development made in recent years, but also the gaps in our present knowledge that most urgently require addressing. Summary: This Review describes the morphological and functional maturation of cells in the mammalian main olfactory bulb, from embryonic development to adult neurogenesis.
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Affiliation(s)
- Candida Tufo
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Subathra Poopalasundaram
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Ana Dorrego-Rivas
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Marc C Ford
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Anthony Graham
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
| | - Matthew S Grubb
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, UK
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23
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Manjally AV, Tay TL. Attack of the Clones: Microglia in Health and Disease. Front Cell Neurosci 2022; 16:831747. [PMID: 35173585 PMCID: PMC8841846 DOI: 10.3389/fncel.2022.831747] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/10/2022] [Indexed: 12/14/2022] Open
Affiliation(s)
- Amritha Vinayak Manjally
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools Centre, University of Freiburg, Freiburg, Germany
- Department of Biology, Boston University, Boston, MA, United States
| | - Tuan Leng Tay
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools Centre, University of Freiburg, Freiburg, Germany
- Department of Biology, Boston University, Boston, MA, United States
- Freiburg Institute of Advanced Studies, University of Freiburg, Freiburg, Germany
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Tuan Leng Tay
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24
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Malloul H, Bonzano S, Bennis M, De Marchis S, Ba-M'hamed S. Chronic thinner inhalation alters olfactory behaviors in adult mice. Behav Brain Res 2022; 417:113597. [PMID: 34563601 DOI: 10.1016/j.bbr.2021.113597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 09/01/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022]
Abstract
Volatile solvents exposure can result in various behavioral impairments that have been partly associated to altered adult hippocampal neurogenesis. Despite recent evidence supporting this association, few studies have been devoted to examine the impact on olfactory functioning and olfactory bulb (OB) neurogenesis, although olfactory system is directly in contact with volatile molecules. Thus, this study was designed to evaluate in adult mice the potential modifications of the olfactory functioning after acute (1 day), subchronic (6 weeks) and chronic (12 weeks) exposure to thinner vapor at both behavioral and cellular levels. Firstly, behavioral evaluations showed that chronic thinner exposure impacts on odor detection ability of treated mice but does not affect mice ability to efficiently discriminate between two different odors. Moreover, chronic thinner exposure produces impairment in the olfactory-mediated associative memory. Secondly, analysis of the effects of thinner exposure in the subventricular zone (SVZ) of the lateral ventricle and in the OB revealed that thinner treatments do not induce apoptosis nor glial activation. Thirdly, immunohistochemical quantification of different markers of adult olfactory neurogenesis showed that inhalant treatments do not change the number of proliferating progenitors in the SVZ and the rostral migratory stream (RMS), as well as the number of newborn cells reaching and integrating in the OB circuitry. Altogether, our data highlight that the impaired olfactory performances in chronically-exposed mice are not associated to an alteration of adult neurogenesis in the SVZ-OB system.
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Affiliation(s)
- Hanaa Malloul
- Laboratory of Pharmacology, Neurobiology, Anthropobiology and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco; Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Mohammed Bennis
- Laboratory of Pharmacology, Neurobiology, Anthropobiology and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco.
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, Italy
| | - Saadia Ba-M'hamed
- Laboratory of Pharmacology, Neurobiology, Anthropobiology and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
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25
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Bedolla A, Taranov A, Luo F, Wang J, Turcato F, Fugate EM, Greig NH, Lindquist DM, Crone SA, Goto J, Luo Y. Diphtheria toxin induced but not CSF1R inhibitor mediated microglia ablation model leads to the loss of CSF/ventricular spaces in vivo that is independent of cytokine upregulation. J Neuroinflammation 2022; 19:3. [PMID: 34983562 PMCID: PMC8728932 DOI: 10.1186/s12974-021-02367-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/20/2021] [Indexed: 01/08/2023] Open
Abstract
Background Two recently developed novel rodent models have been reported to ablate microglia, either by genetically targeting microglia (via Cx3cr1-creER: iDTR + Dtx) or through pharmacologically targeting the CSF1R receptor with its inhibitor (PLX5622). Both models have been widely used in recent years to define essential functions of microglia and have led to high impact studies that have moved the field forward. Methods Using either Cx3cr1-iDTR mice in combination with Dtx or via the PLX5622 diet to pharmacologically ablate microglia, we compared the two models via MRI and histology to study the general anatomy of the brain and the CSF/ventricular systems. Additionally, we analyzed the cytokine profile in both microglia ablation models. Results We discovered that the genetic ablation (Cx3cr1-iDTR + Dtx), but not the pharmacological microglia ablation (PLX5622), displays a surprisingly rapid pathological condition in the brain represented by loss of CSF/ventricles without brain parenchymal swelling. This phenotype was observed both in MRI and histological analysis. To our surprise, we discovered that the iDTR allele alone leads to the loss of CSF/ventricles phenotype following diphtheria toxin (Dtx) treatment independent of cre expression. To examine the underlying mechanism for the loss of CSF in the Cx3cr1-iDTR ablation and iDTR models, we additionally investigated the cytokine profile in the Cx3cr1-iDTR + Dtx, iDTR + Dtx and the PLX models. We found increases of multiple cytokines in the Cx3cr1-iDTR + Dtx but not in the pharmacological ablation model nor the iDTR + Dtx mouse brains at the time of CSF loss (3 days after the first Dtx injection). This result suggests that the upregulation of cytokines is not the cause of the loss of CSF, which is supported by our data indicating that brain parenchyma swelling, or edema are not observed in the Cx3cr1-iDTR + Dtx microglia ablation model. Additionally, pharmacological inhibition of the KC/CXCR2 pathway (the most upregulated cytokine in the Cx3cr1-iDTR + Dtx model) did not resolve the CSF/ventricular loss phenotype in the genetic microglia ablation model. Instead, both the Cx3cr1-iDTR + Dtx ablation and iDTR + Dtx models showed increased activated IBA1 + cells in the choroid plexus (CP), suggesting that CP-related pathology might be the contributing factor for the observed CSF/ventricular shrinkage phenotype. Conclusions Our data, for the first time, reveal a robust and global CSF/ventricular space shrinkage pathology in the Cx3cr1-iDTR genetic ablation model caused by iDTR allele, but not in the PLX5622 ablation model, and suggest that this pathology is not due to brain edema formation but to CP related pathology. Given the wide utilization of the iDTR allele and the Cx3cr1-iDTR model, it is crucial to fully characterize this pathology to understand the underlying causal mechanisms. Specifically, caution is needed when utilizing this model to interpret subtle neurologic functional changes that are thought to be mediated by microglia but could, instead, be due to CSF/ventricular loss in the genetic ablation model.
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Affiliation(s)
- Alicia Bedolla
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Aleksandr Taranov
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Fucheng Luo
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Jiapeng Wang
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Flavia Turcato
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Elizabeth M Fugate
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Department of Radiology, University of Cincinnati, Cincinnati, USA
| | - Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute On Aging, National Institutes of Health, Baltimore, USA
| | - Diana M Lindquist
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Department of Radiology, University of Cincinnati, Cincinnati, USA
| | - Steven A Crone
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Department of Neurosurgery, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA
| | - June Goto
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA.,Department of Neurosurgery, College of Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, 45267, USA
| | - Yu Luo
- Department of Molecular Genetics and Biochemistry, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
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26
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Lakshmanan HG, Miller E, White-Canale A, McCluskey LP. Immune responses in the injured olfactory and gustatory systems: a role in olfactory receptor neuron and taste bud regeneration? Chem Senses 2022; 47:bjac024. [PMID: 36152297 PMCID: PMC9508897 DOI: 10.1093/chemse/bjac024] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sensory cells that specialize in transducing olfactory and gustatory stimuli are renewed throughout life and can regenerate after injury unlike their counterparts in the mammalian retina and auditory epithelium. This uncommon capacity for regeneration offers an opportunity to understand mechanisms that promote the recovery of sensory function after taste and smell loss. Immune responses appear to influence degeneration and later regeneration of olfactory sensory neurons and taste receptor cells. Here we review surgical, chemical, and inflammatory injury models and evidence that immune responses promote or deter chemosensory cell regeneration. Macrophage and neutrophil responses to chemosensory receptor injury have been the most widely studied without consensus on their net effects on regeneration. We discuss possible technical and biological reasons for the discrepancy, such as the difference between peripheral and central structures, and suggest directions for progress in understanding immune regulation of chemosensory regeneration. Our mechanistic understanding of immune-chemosensory cell interactions must be expanded before therapies can be developed for recovering the sensation of taste and smell after head injury from traumatic nerve damage and infection. Chemosensory loss leads to decreased quality of life, depression, nutritional challenges, and exposure to environmental dangers highlighting the need for further studies in this area.
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Affiliation(s)
- Hari G Lakshmanan
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Elayna Miller
- Department of Medical Illustration, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - AnnElizabeth White-Canale
- Department of Medical Illustration, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Lynnette P McCluskey
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
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27
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Crapser JD, Arreola MA, Tsourmas KI, Green KN. Microglia as hackers of the matrix: sculpting synapses and the extracellular space. Cell Mol Immunol 2021; 18:2472-2488. [PMID: 34413489 PMCID: PMC8546068 DOI: 10.1038/s41423-021-00751-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia shape the synaptic environment in health and disease, but synapses do not exist in a vacuum. Instead, pre- and postsynaptic terminals are surrounded by extracellular matrix (ECM), which together with glia comprise the four elements of the contemporary tetrapartite synapse model. While research in this area is still just beginning, accumulating evidence points toward a novel role for microglia in regulating the ECM during normal brain homeostasis, and such processes may, in turn, become dysfunctional in disease. As it relates to synapses, microglia are reported to modify the perisynaptic matrix, which is the diffuse matrix that surrounds dendritic and axonal terminals, as well as perineuronal nets (PNNs), specialized reticular formations of compact ECM that enwrap neuronal subsets and stabilize proximal synapses. The interconnected relationship between synapses and the ECM in which they are embedded suggests that alterations in one structure necessarily affect the dynamics of the other, and microglia may need to sculpt the matrix to modify the synapses within. Here, we provide an overview of the microglial regulation of synapses, perisynaptic matrix, and PNNs, propose candidate mechanisms by which these structures may be modified, and present the implications of such modifications in normal brain homeostasis and in disease.
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Affiliation(s)
- Joshua D. Crapser
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Miguel A. Arreola
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kate I. Tsourmas
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kim N. Green
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
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28
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Borst K, Dumas AA, Prinz M. Microglia: Immune and non-immune functions. Immunity 2021; 54:2194-2208. [PMID: 34644556 DOI: 10.1016/j.immuni.2021.09.014] [Citation(s) in RCA: 235] [Impact Index Per Article: 78.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/20/2021] [Accepted: 09/16/2021] [Indexed: 12/21/2022]
Abstract
As resident macrophages of the central nervous system (CNS), microglia are associated with diverse functions essential to the developing and adult brain during homeostasis and disease. They are aided in their tasks by intricate bidirectional communication with other brain cells under steady-state conditions as well as with infiltrating peripheral immune cells during perturbations. Harmonious cell-cell communication involving microglia are considered crucial to maintain the healthy state of the tissue environment and to overcome pathology such as neuroinflammation. Analyses of such intercellular pathways have contributed to our understanding of the heterogeneous but context-associated microglial responses to environmental cues across neuropathology, including inflammatory conditions such as infections and autoimmunity, as well as immunosuppressive states as seen in brain tumors. Here, we summarize the latest evidence demonstrating how these interactions drive microglia immune and non-immune functions, which coordinate the transition from homeostatic to disease-related cellular states.
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Affiliation(s)
- Katharina Borst
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Anaelle Aurelie Dumas
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany; Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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29
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De Schepper S, Crowley G, Hong S. Understanding microglial diversity and implications for neuronal function in health and disease. Dev Neurobiol 2021; 81:507-523. [PMID: 32757416 PMCID: PMC8438703 DOI: 10.1002/dneu.22777] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 06/21/2020] [Accepted: 07/31/2020] [Indexed: 12/22/2022]
Abstract
Genetic data implicate microglia as central players in brain health and disease, urging the need to better understand what microglia do in the brain. Microglia are critical partners in neuronal wiring and function during development and disease. Emerging literature suggests that microglia have diverse functional roles, raising the intriguing question of which functions of microglia become impaired in disease to undermine proper neuronal function. It is also becoming increasingly clear that microglia exist in heterogeneous cell states. Microglial cell states appear context-dependent, that is, age, sex, location, and health of their microenvironment; these are further influenced by external signaling factors including gut microbiota and lipid metabolites. These data altogether suggest that microglia exist in functional clusters that impact, and are impacted by, surrounding neuronal microenvironment. However, we still lack understanding of how we can translate microglia cell states into function. Here, we summarize the state-of-the-art on the diverse functions of microglia in relation to neuronal health. Then, we discuss heterogeneity during developing, healthy adult and diseased brains, and whether this may be predetermined by origin and/or regulated by local milieu. Finally, we propose that it is critical to gain high-resolution functional discernment into microglia-neuron interactions while preserving the spatial architecture of the tissue. Such insight will reveal specific targets for biomarker and therapeutic development toward microglia-neuron crosstalk in disease.
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Affiliation(s)
| | - Gerard Crowley
- UK Dementia Research InstituteUniversity College LondonLondonUK
| | - Soyon Hong
- UK Dementia Research InstituteUniversity College LondonLondonUK
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30
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Beecher K, Wang J, Jacques A, Chaaya N, Chehrehasa F, Belmer A, Bartlett SE. Sucrose Consumption Alters Serotonin/Glutamate Co-localisation Within the Prefrontal Cortex and Hippocampus of Mice. Front Mol Neurosci 2021; 14:678267. [PMID: 34262435 PMCID: PMC8273284 DOI: 10.3389/fnmol.2021.678267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/08/2021] [Indexed: 01/23/2023] Open
Abstract
The overconsumption of sugar-sweetened food and beverages underpins the current rise in obesity rates. Sugar overconsumption induces maladaptive neuroplasticity to decrease dietary control. Although serotonin and glutamate co-localisation has been implicated in reward processing, it is still unknown how chronic sucrose consumption changes this transmission in regions associated with executive control over feeding—such as the prefrontal cortex (PFC) and dentate gyrus (DG) of the hippocampus. To address this, a total of 16 C57Bl6 mice received either 5% w/v sucrose or water as a control for 12 weeks using the Drinking-In-The-Dark paradigm (n = 8 mice per group). We then examined the effects of chronic sucrose consumption on the immunological distribution of serotonin (5-HT), vesicular glutamate transporter 3 (VGLUT3) and 5-HT+/VGLUT3+ co-localised axonal varicosities. Sucrose consumption over 12 weeks decreased the number of 5-HT–/VGLUT3+ and 5-HT+/VGLUT3+ varicosities within the PFC and DG. The number of 5-HT+/VGLUT3– varicosities remained unchanged within the PFC but decreased in the DG following sucrose consumption. Given that serotonin mediates DG neurogenesis through microglial migration, the number of microglia within the DG was also assessed in both experimental groups. Sucrose consumption decreased the number of DG microglia. Although the DG and PFC are associated with executive control over rewarding activities and emotional memory formation, we did not detect a subsequent change in DG neurogenesis or anxiety-like behaviour or depressive-like behaviour. Overall, these findings suggest that the chronic consumption of sugar alters serotonergic neuroplasticity within neural circuits responsible for feeding control. Although these alterations alone were not sufficient to induce changes in neurogenesis or behaviour, it is proposed that the sucrose consumption may predispose individuals to these cognitive deficits which ultimately promote further sugar intake.
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Affiliation(s)
- Kate Beecher
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Joshua Wang
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Angela Jacques
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Nicholas Chaaya
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Fatemeh Chehrehasa
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Arnauld Belmer
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Selena E Bartlett
- Addiction Neuroscience and Obesity Laboratory, Faculty of Health, School of Clinical Sciences, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
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Zheng T, Zhang Z. Activated microglia facilitate the transmission of α-synuclein in Parkinson's disease. Neurochem Int 2021; 148:105094. [PMID: 34097990 DOI: 10.1016/j.neuint.2021.105094] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 05/23/2021] [Accepted: 05/31/2021] [Indexed: 01/31/2023]
Abstract
Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta and abnormal aggregates of α-synuclein protein called Lewy bodies. To date, there is no drug that can definitely slow down or stop the progression of this disease. The discovery of the cell-to-cell transmission of pathologic α-synuclein seeds offers the possibility to explore novel treatment strategies to prevent the spread of α-synuclein, with the purpose of slowing down the progression of PD in its tracks. Although recent studies have made tremendous progress in understanding how α-synuclein spreads throughout the brain, neuroinflammation seems to play a crucial role in the development of α-synuclein pathology in PD. The activation of microglia, one of the hallmarks of the neuroinflammatory process, is suggested to influence the neuron-to-neuron transmission of α-synuclein. This review summarizes how activated microglia facilitate this process, and focuses on the following mechanisms including the activation of microglia in PD, the reduced ability of activated microglia to clear α-synuclein and increased migratory capacity of microglia in PD, as well as the cooperation between microglia and exosomes in mediating α-synuclein release and propagation. In conclusion, this article help collate information on microglia in-relation to PD.
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Affiliation(s)
- Tingting Zheng
- Department of Neurology, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Traditional Chinese Medicine), 54 Youdian Road, Hangzhou 310006, China
| | - Zhengxiang Zhang
- Department of Neurology, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Traditional Chinese Medicine), 54 Youdian Road, Hangzhou 310006, China.
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Tucić M, Stamenković V, Andjus P. The Extracellular Matrix Glycoprotein Tenascin C and Adult Neurogenesis. Front Cell Dev Biol 2021; 9:674199. [PMID: 33996833 PMCID: PMC8117239 DOI: 10.3389/fcell.2021.674199] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/09/2021] [Indexed: 11/13/2022] Open
Abstract
Tenascin C (TnC) is a glycoprotein highly expressed in the extracellular matrix (ECM) during development and in the adult central nervous system (CNS) in regions of active neurogenesis, where neuron development is a tightly regulated process orchestrated by extracellular matrix components. In addition, newborn cells also communicate with glial cells, astrocytes and microglia, indicating the importance of signal integration in adult neurogenesis. Although TnC has been recognized as an important molecule in the regulation of cell proliferation and migration, complete regulatory pathways still need to be elucidated. In this review we discuss the formation of new neurons in the adult hippocampus and the olfactory system with specific reference to TnC and its regulating functions in this process. Better understanding of the ECM signaling in the niche of the CNS will have significant implications for regenerative therapies.
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Affiliation(s)
- Milena Tucić
- Center for Laser Microscopy, Institute for Physiology and Biochemistry "Jean Giaja", Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Vera Stamenković
- Center for Laser Microscopy, Institute for Physiology and Biochemistry "Jean Giaja", Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Pavle Andjus
- Center for Laser Microscopy, Institute for Physiology and Biochemistry "Jean Giaja", Faculty of Biology, University of Belgrade, Belgrade, Serbia
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Selective Ablation of BDNF from Microglia Reveals Novel Roles in Self-Renewal and Hippocampal Neurogenesis. J Neurosci 2021; 41:4172-4186. [PMID: 33785644 DOI: 10.1523/jneurosci.2539-20.2021] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 02/18/2021] [Accepted: 03/16/2021] [Indexed: 01/22/2023] Open
Abstract
Microglia, the resident immune cells of the CNS, have emerged as key regulators of neural precursor cell activity in the adult brain. However, the microglia-derived factors that mediate these effects remain largely unknown. In the present study, we investigated a role for microglial brain-derived neurotrophic factor (BDNF), a neurotrophic factor with well known effects on neuronal survival and plasticity. Surprisingly, we found that selective genetic ablation of BDNF from microglia increased the production of newborn neurons under both physiological and inflammatory conditions (e.g., LPS-induced infection and traumatic brain injury). Genetic ablation of BDNF from microglia otherwise also interfered with self-renewal/proliferation, reducing their overall density. In conclusion, we identify microglial BDNF as an important factor regulating microglia population dynamics and states, which in turn influences neurogenesis under both homeostatic and pathologic conditions.SIGNIFICANCE STATEMENT (1) Microglial BDNF contributes to self-renewal and density of microglia in the brain. (2) Selective ablation of BDNF in microglia stimulates neural precursor proliferation. (3) Loss of microglial BDNF augments working memory following traumatic brain injury. (4) Benefits of repopulating microglia on brain injury are not mediated via microglial BDNF.
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Lim TKY, Ruthazer ES. Microglial trogocytosis and the complement system regulate axonal pruning in vivo. eLife 2021; 10:e62167. [PMID: 33724186 PMCID: PMC7963485 DOI: 10.7554/elife.62167] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 02/28/2021] [Indexed: 12/14/2022] Open
Abstract
Partial phagocytosis-called trogocytosis-of axons by microglia has been documented in ex vivo preparations but has not been directly observed in vivo. The mechanisms that modulate microglial trogocytosis of axons and its function in neural circuit development remain poorly understood. Here, we directly observe axon trogocytosis by microglia in vivo in the developing Xenopus laevis retinotectal circuit. We show that microglia regulate pruning of retinal ganglion cell axons and are important for proper behavioral response to dark and bright looming stimuli. Using bioinformatics, we identify amphibian regulator of complement activation 3, a homolog of human CD46, as a neuronally expressed synapse-associated complement inhibitory molecule that inhibits trogocytosis and axonal pruning. Using a membrane-bound complement C3 fusion protein, we demonstrate that enhancing complement activity enhances axonal pruning. Our results support the model that microglia remodel axons via trogocytosis and that neurons can control this process through expression of complement inhibitory proteins.
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Affiliation(s)
- Tony KY Lim
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
| | - Edward S Ruthazer
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill UniversityMontrealCanada
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35
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Andoh M, Koyama R. Microglia regulate synaptic development and plasticity. Dev Neurobiol 2021; 81:568-590. [PMID: 33583110 PMCID: PMC8451802 DOI: 10.1002/dneu.22814] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
Synapses are fundamental structures of neural circuits that transmit information between neurons. Thus, the process of neural circuit formation via proper synaptic connections shapes the basis of brain functions and animal behavior. Synapses continuously undergo repeated formation and elimination throughout the lifetime of an organism, reflecting the dynamics of neural circuit function. The structural transformation of synapses has been described mainly in relation to neural activity-dependent strengthening and weakening of synaptic functions, that is, functional plasticity of synapses. An increasing number of studies have unveiled the roles of microglia, brain-resident immune cells that survey the brain parenchyma with highly motile processes, in synapse formation and elimination as well as in regulating synaptic function. Over the past 15 years, the molecular mechanisms underlying microglia-dependent regulation of synaptic plasticity have been thoroughly studied, and researchers have reported that the disruption of microglia-dependent regulation causes synaptic dysfunction that leads to brain diseases. In this review, we will broadly introduce studies that report the roles of microglia in synaptic plasticity and the possible underlying molecular mechanisms.
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Affiliation(s)
- Megumi Andoh
- 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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36
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Chintamen S, Imessadouene F, Kernie SG. Immune Regulation of Adult Neurogenic Niches in Health and Disease. Front Cell Neurosci 2021; 14:571071. [PMID: 33551746 PMCID: PMC7855589 DOI: 10.3389/fncel.2020.571071] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/23/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia regulate neuronal development during embryogenesis, postnatal development, and in specialized microenvironments of the adult brain. Recent evidence demonstrates that in adulthood, microglia secrete factors which modulate adult hippocampal neurogenesis by inhibiting cell proliferation and survival both in vitro and in vivo, maintaining a balance between cell division and cell death in neurogenic niches. These resident immune cells also shape the nervous system by actively pruning synapses during critical periods of learning and engulfing excess neurons. In neurodegenerative diseases, aberrant microglial activity can impede the proper formation and prevent the development of appropriate functional properties of adult born granule cells. Ablating microglia has been presented as a promising therapeutic approach to alleviate the brain of maladaptive immune response. Here, we review key mechanisms through which the immune system actively shapes neurogenic niches throughout the lifespan of the mammalian brain in both health and disease. We discuss how interactions between immune cells and developing neurons may be leveraged for pharmacological intervention and as a means to preserve adult neurogenesis.
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Affiliation(s)
- Sana Chintamen
- Neurobiology and Behavior, Columbia University Irving Medical Center, New York, NY, United States.,Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
| | - Fatima Imessadouene
- Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
| | - Steven G Kernie
- Department of Pediatrics, Columbia University Irving Fefere Medical Center, New York, NY, United States
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37
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Eme-Scolan E, Dando SJ. Tools and Approaches for Studying Microglia In vivo. Front Immunol 2020; 11:583647. [PMID: 33117395 PMCID: PMC7576994 DOI: 10.3389/fimmu.2020.583647] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/24/2020] [Indexed: 12/13/2022] Open
Abstract
Microglia are specialized resident macrophages of the central nervous system (CNS) that have important functions during neurodevelopment, homeostasis and disease. This mini-review provides an overview of the current tools and approaches for studying microglia in vivo. We focus on tools for labeling microglia, highlighting the advantages and limitations of microglia markers/antibodies and reporter mice. We also discuss techniques for imaging microglia in situ, including in vivo live imaging of brain and retinal microglia. Finally, we review microglia depletion approaches and their use to investigate microglial function in CNS homeostasis and disease.
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Affiliation(s)
- Elisa Eme-Scolan
- École Normale Supérieure de Lyon, Université Claude Bernard Lyon I, Université de Lyon, Lyon, France.,Faculty of Health, Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Samantha J Dando
- Faculty of Health, Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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Malvaut S, Constantinescu VS, Dehez H, Doric S, Saghatelyan A. Deciphering Brain Function by Miniaturized Fluorescence Microscopy in Freely Behaving Animals. Front Neurosci 2020; 14:819. [PMID: 32848576 PMCID: PMC7432153 DOI: 10.3389/fnins.2020.00819] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/14/2020] [Indexed: 11/19/2022] Open
Abstract
Animal behavior is regulated by environmental stimuli and is shaped by the activity of neural networks, underscoring the importance of assessing the morpho-functional properties of different populations of cells in freely behaving animals. In recent years, a number of optical tools have been developed to monitor and modulate neuronal and glial activity at the protein, cellular, or network level and have opened up new avenues for studying brain function in freely behaving animals. Tools such as genetically encoded sensors and actuators are now commonly used for studying brain activity and function through their expression in different neuronal ensembles. In parallel, microscopy has also made major progress over the last decades. The advent of miniature microscopes (mini-microscopes also called mini-endoscopes) has become a method of choice for studying brain activity at the cellular and network levels in different brain regions of freely behaving mice. This technique also allows for longitudinal investigations while animals carrying the microscope on their head are performing behavioral tasks. In this review, we will discuss mini-endoscopic imaging and the advantages that these devices offer to research. We will also discuss current limitations of and potential future improvements in mini-endoscopic imaging.
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Affiliation(s)
- Sarah Malvaut
- CERVO Brain Research Center, Quebec City, QC, Canada
- Department of Psychiatry and Neuroscience, Universite Laval, Quebec City, QC, Canada
| | - Vlad-Stefan Constantinescu
- CERVO Brain Research Center, Quebec City, QC, Canada
- Department of Psychiatry and Neuroscience, Universite Laval, Quebec City, QC, Canada
| | | | - Sead Doric
- Doric Lenses Inc., Quebec City, QC, Canada
| | - Armen Saghatelyan
- CERVO Brain Research Center, Quebec City, QC, Canada
- Department of Psychiatry and Neuroscience, Universite Laval, Quebec City, QC, Canada
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