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Kent SA, Miron VE. Microglia regulation of central nervous system myelin health and regeneration. Nat Rev Immunol 2024; 24:49-63. [PMID: 37452201 DOI: 10.1038/s41577-023-00907-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/18/2023]
Abstract
Microglia are resident macrophages of the central nervous system that have key functions in its development, homeostasis and response to damage and infection. Although microglia have been increasingly implicated in contributing to the pathology that underpins neurological dysfunction and disease, they also have crucial roles in neurological homeostasis and regeneration. This includes regulation of the maintenance and regeneration of myelin, the membrane that surrounds neuronal axons, which is required for axonal health and function. Myelin is damaged with normal ageing and in several neurodegenerative diseases, such as multiple sclerosis and Alzheimer disease. Given the lack of approved therapies targeting myelin maintenance or regeneration, it is imperative to understand the mechanisms by which microglia support and restore myelin health to identify potential therapeutic approaches. However, the mechanisms by which microglia regulate myelin loss or integrity are still being uncovered. In this Review, we discuss recent work that reveals the changes in white matter with ageing and neurodegenerative disease, how this relates to microglia dynamics during myelin damage and regeneration, and factors that influence the regenerative functions of microglia.
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Affiliation(s)
- Sarah A Kent
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK
| | - Veronique E Miron
- UK Dementia Research Institute at The University of Edinburgh, Edinburgh, UK.
- Centre for Discovery Brain Sciences, Chancellor's Building, The University of Edinburgh, Edinburgh, UK.
- Barlo Multiple Sclerosis Centre, St Michael's Hospital, Toronto, Ontario, Canada.
- Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, Ontario, Canada.
- Department of Immunology, The University of Toronto, Toronto, Ontario, Canada.
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2
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Connors J, Cusimano G, Mege N, Woloszczuk K, Konopka E, Bell M, Joyner D, Marcy J, Tardif V, Kutzler MA, Muir R, Haddad EK. Using the power of innate immunoprofiling to understand vaccine design, infection, and immunity. Hum Vaccin Immunother 2023; 19:2267295. [PMID: 37885158 PMCID: PMC10760375 DOI: 10.1080/21645515.2023.2267295] [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: 07/13/2023] [Accepted: 10/03/2023] [Indexed: 10/28/2023] Open
Abstract
In the field of immunology, a systems biology approach is crucial to understanding the immune response to infection and vaccination considering the complex interplay between genetic, epigenetic, and environmental factors. Significant progress has been made in understanding the innate immune response, including cell players and critical signaling pathways, but many questions remain unanswered, including how the innate immune response dictates host/pathogen responses and responses to vaccines. To complicate things further, it is becoming increasingly clear that the innate immune response is not a linear pathway but is formed from complex networks and interactions. To further our understanding of the crosstalk and complexities, systems-level analyses and expanded experimental technologies are now needed. In this review, we discuss the most recent immunoprofiling techniques and discuss systems approaches to studying the global innate immune landscape which will inform on the development of personalized medicine and innovative vaccine strategies.
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Affiliation(s)
- Jennifer Connors
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gina Cusimano
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Nathan Mege
- Tower Health, Reading Hospital, West Reading, PA, USA
| | - Kyra Woloszczuk
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Emily Konopka
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Matthew Bell
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - David Joyner
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Molecular and Cellular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jennifer Marcy
- Department of Molecular and Cellular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Virginie Tardif
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Michele A. Kutzler
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Roshell Muir
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Family, Community, and Preventative Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Elias K. Haddad
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
- Department of Medicine, Division of Infectious Diseases and HIV Medicine, Drexel University College of Medicine, Philadelphia, PA, USA
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3
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Vakrakou AG, Brinia ME, Alexaki A, Koumasopoulos E, Stathopoulos P, Evangelopoulos ME, Stefanis L, Stadelmann-Nessler C, Kilidireas C. Multiple faces of multiple sclerosis in the era of highly efficient treatment modalities: Lymphopenia and switching treatment options challenges daily practice. Int Immunopharmacol 2023; 125:111192. [PMID: 37951198 DOI: 10.1016/j.intimp.2023.111192] [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: 09/03/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 11/13/2023]
Abstract
The expanded treatment landscape in relapsing-remitting multiple sclerosis (MS) has resulted in highly effective treatment options and complexity in managing disease- or drug-related events during disease progression. Proper decision-making requires thorough knowledge of the immunobiology of MS itself and an understanding of the main principles behind the mechanisms that lead to secondary autoimmunity affecting organs other than the central nervous system as well as opportunistic infections. The immune system is highly adapted to both environmental and disease-modifying agents. Immune reconstitution following cell depletion or cell entrapment therapies eliminates pathogenic aspects of the disease but can also lead to distorted immune responses with harmful effects. Atypical relapses occur with second-line treatments or after their discontinuation and require appropriate clinical decisions. Lymphopenia is a result of the mechanism of action of many drugs used to treat MS. However, persistent lymphopenia and cell-specific lymphopenia could result in disease exacerbation, secondary autoimmunity, or the emergence of opportunistic infections. Clinicians treating patients with MS should be aware of the multiple faces of MS under novel, efficient treatment modalities and understand the intricate brain-immune cell interactions in the context of an altered immune system. MS relapses and disease progression still occur despite the current treatment modalities and are mediated either by failure to control effector mechanisms inherent to MS pathophysiology or by new drug-related mechanisms. The multiple faces of MS due to the highly adapted immune system of patients impose the need for appropriate switching therapies that safeguard disease remission and further clinical improvement.
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Affiliation(s)
- Aigli G Vakrakou
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece; Department of Neuropathology, University of Göttingen Medical Center, Göttingen, Germany.
| | - Maria-Evgenia Brinia
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasia Alexaki
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelos Koumasopoulos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Panos Stathopoulos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria-Eleftheria Evangelopoulos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Leonidas Stefanis
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Constantinos Kilidireas
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aiginition Hospital, National and Kapodistrian University of Athens, Athens, Greece; Department of Neurology, Henry Dunant Hospital Center, Athens, Greece
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Pukoli D, Vécsei L. Smouldering Lesion in MS: Microglia, Lymphocytes and Pathobiochemical Mechanisms. Int J Mol Sci 2023; 24:12631. [PMID: 37628811 PMCID: PMC10454160 DOI: 10.3390/ijms241612631] [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: 07/18/2023] [Revised: 08/05/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Multiple sclerosis (MS) is an immune-mediated, chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). Immune cell infiltration can lead to permanent activation of macrophages and microglia in the parenchyma, resulting in demyelination and neurodegeneration. Thus, neurodegeneration that begins with acute lymphocytic inflammation may progress to chronic inflammation. This chronic inflammation is thought to underlie the development of so-called smouldering lesions. These lesions evolve from acute inflammatory lesions and are associated with continuous low-grade demyelination and neurodegeneration over many years. Their presence is associated with poor disease prognosis and promotes the transition to progressive MS, which may later manifest clinically as progressive MS when neurodegeneration exceeds the upper limit of functional compensation. In smouldering lesions, in the presence of only moderate inflammatory activity, a toxic environment is clearly identifiable and contributes to the progressive degeneration of neurons, axons, and oligodendrocytes and, thus, to clinical disease progression. In addition to the cells of the immune system, the development of oxidative stress in MS lesions, mitochondrial damage, and hypoxia caused by the resulting energy deficit and iron accumulation are thought to play a role in this process. In addition to classical immune mediators, this chronic toxic environment contains high concentrations of oxidants and iron ions, as well as the excitatory neurotransmitter glutamate. In this review, we will discuss how these pathobiochemical markers and mechanisms, alone or in combination, lead to neuronal, axonal, and glial cell death and ultimately to the process of neuroinflammation and neurodegeneration, and then discuss the concepts and conclusions that emerge from these findings. Understanding the role of these pathobiochemical markers would be important to gain a better insight into the relationship between the clinical classification and the pathomechanism of MS.
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Affiliation(s)
- Dániel Pukoli
- Department of Neurology, Esztergomi Vaszary Kolos Hospital, 2500 Esztergom, Hungary;
| | - László Vécsei
- Department of Neurology, Faculty of Medicine, University of Szeged, Semmelweis u. 6., H-6725 Szeged, Hungary
- Danube Neuroscience Research Laboratory, ELKH-SZTE Neuroscience Research Group, Eötvös Loránd Research Network, University of Szeged (ELKH-SZTE), Tisza Lajos krt. 113, H-6725 Szeged, Hungary
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5
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Bittner S, Pape K, Klotz L, Zipp F. Implications of immunometabolism for smouldering MS pathology and therapy. Nat Rev Neurol 2023:10.1038/s41582-023-00839-6. [PMID: 37430070 DOI: 10.1038/s41582-023-00839-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2023] [Indexed: 07/12/2023]
Abstract
Clinical symptom worsening in patients with multiple sclerosis (MS) is driven by inflammation compartmentalized within the CNS, which results in chronic neuronal damage owing to insufficient repair mechanisms. The term 'smouldering inflammation' summarizes the biological aspects underlying this chronic, non-relapsing and immune-mediated mechanism of disease progression. Smouldering inflammation is likely to be shaped and sustained by local factors in the CNS that account for the persistence of this inflammatory response and explain why current treatments for MS do not sufficiently target this process. Local factors that affect the metabolic properties of glial cells and neurons include cytokines, pH value, lactate levels and nutrient availability. This Review summarizes current knowledge of the local inflammatory microenvironment in smouldering inflammation and how it interacts with the metabolism of tissue-resident immune cells, thereby promoting inflammatory niches within the CNS. The discussion highlights environmental and lifestyle factors that are increasingly recognized as capable of altering immune cell metabolism and potentially responsible for smouldering pathology in the CNS. Currently approved MS therapies that target metabolic pathways are also discussed, along with their potential for preventing the processes that contribute to smouldering inflammation and thereby to progressive neurodegenerative damage in MS.
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Affiliation(s)
- Stefan Bittner
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
| | - Katrin Pape
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Luisa Klotz
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Frauke Zipp
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine-Main Neuroscience Network (rmn2), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
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6
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Distéfano-Gagné F, Bitarafan S, Lacroix S, Gosselin D. Roles and regulation of microglia activity in multiple sclerosis: insights from animal models. Nat Rev Neurosci 2023:10.1038/s41583-023-00709-6. [PMID: 37268822 DOI: 10.1038/s41583-023-00709-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/04/2023]
Abstract
As resident macrophages of the CNS, microglia are critical immune effectors of inflammatory lesions and associated neural dysfunctions. In multiple sclerosis (MS) and its animal models, chronic microglial inflammatory activity damages myelin and disrupts axonal and synaptic activity. In contrast to these detrimental effects, the potent phagocytic and tissue-remodelling capabilities of microglia support critical endogenous repair mechanisms. Although these opposing capabilities have long been appreciated, a precise understanding of their underlying molecular effectors is only beginning to emerge. Here, we review recent advances in our understanding of the roles of microglia in animal models of MS and demyelinating lesions and the mechanisms that underlie their damaging and repairing activities. We also discuss how the structured organization and regulation of the genome enables complex transcriptional heterogeneity within the microglial cell population at demyelinating lesions.
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Affiliation(s)
- Félix Distéfano-Gagné
- Axe Neuroscience, Centre de Recherche du CHU de Québec - Université Laval, Québec, Québec, Canada
- Département de Médecine Moléculaire de la Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Sara Bitarafan
- Axe Neuroscience, Centre de Recherche du CHU de Québec - Université Laval, Québec, Québec, Canada
- Département de Médecine Moléculaire de la Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Steve Lacroix
- Axe Neuroscience, Centre de Recherche du CHU de Québec - Université Laval, Québec, Québec, Canada
- Département de Médecine Moléculaire de la Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - David Gosselin
- Axe Neuroscience, Centre de Recherche du CHU de Québec - Université Laval, Québec, Québec, Canada.
- Département de Médecine Moléculaire de la Faculté de Médecine, Université Laval, Québec, Québec, Canada.
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7
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Klotz L, Antel J, Kuhlmann T. Inflammation in multiple sclerosis: consequences for remyelination and disease progression. Nat Rev Neurol 2023; 19:305-320. [PMID: 37059811 DOI: 10.1038/s41582-023-00801-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 04/16/2023]
Abstract
Despite the large number of immunomodulatory or immunosuppressive treatments available to treat relapsing-remitting multiple sclerosis (MS), treatment of the progressive phase of the disease has not yet been achieved. This lack of successful treatment approaches is caused by our poor understanding of the mechanisms driving disease progression. Emerging concepts suggest that a combination of persisting focal and diffuse inflammation within the CNS and a gradual failure of compensatory mechanisms, including remyelination, result in disease progression. Therefore, promotion of remyelination presents a promising intervention approach. However, despite our increasing knowledge regarding the cellular and molecular mechanisms regulating remyelination in animal models, therapeutic increases in remyelination remain an unmet need in MS, which suggests that mechanisms of remyelination and remyelination failure differ fundamentally between humans and demyelinating animal models. New and emerging technologies now allow us to investigate the cellular and molecular mechanisms underlying remyelination failure in human tissue samples in an unprecedented way. The aim of this Review is to summarize our current knowledge regarding mechanisms of remyelination and remyelination failure in MS and in animal models of the disease, identify open questions, challenge existing concepts, and discuss strategies to overcome the translational roadblock in the field of remyelination-promoting therapies.
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Affiliation(s)
- Luisa Klotz
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada
| | - Tanja Kuhlmann
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada.
- Institute of Neuropathology, University Hospital Münster, Münster, Germany.
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8
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Advances in Mass Spectrometry-Based Single Cell Analysis. BIOLOGY 2023; 12:biology12030395. [PMID: 36979087 PMCID: PMC10045136 DOI: 10.3390/biology12030395] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023]
Abstract
Technological developments and improvements in single-cell isolation and analytical platforms allow for advanced molecular profiling at the single-cell level, which reveals cell-to-cell variation within the admixture cells in complex biological or clinical systems. This helps to understand the cellular heterogeneity of normal or diseased tissues and organs. However, most studies focused on the analysis of nucleic acids (e.g., DNA and RNA) and mass spectrometry (MS)-based analysis for proteins and metabolites of a single cell lagged until recently. Undoubtedly, MS-based single-cell analysis will provide a deeper insight into cellular mechanisms related to health and disease. This review summarizes recent advances in MS-based single-cell analysis methods and their applications in biology and medicine.
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Pathak D, Sriram K. Molecular Mechanisms Underlying Neuroinflammation Elicited by Occupational Injuries and Toxicants. Int J Mol Sci 2023; 24:ijms24032272. [PMID: 36768596 PMCID: PMC9917383 DOI: 10.3390/ijms24032272] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023] Open
Abstract
Occupational injuries and toxicant exposures lead to the development of neuroinflammation by activating distinct mechanistic signaling cascades that ultimately culminate in the disruption of neuronal function leading to neurological and neurodegenerative disorders. The entry of toxicants into the brain causes the subsequent activation of glial cells, a response known as 'reactive gliosis'. Reactive glial cells secrete a wide variety of signaling molecules in response to neuronal perturbations and thus play a crucial role in the progression and regulation of central nervous system (CNS) injury. In parallel, the roles of protein phosphorylation and cell signaling in eliciting neuroinflammation are evolving. However, there is limited understanding of the molecular underpinnings associated with toxicant- or occupational injury-mediated neuroinflammation, gliosis, and neurological outcomes. The activation of signaling molecules has biological significance, including the promotion or inhibition of disease mechanisms. Nevertheless, the regulatory mechanisms of synergism or antagonism among intracellular signaling pathways remain elusive. This review highlights the research focusing on the direct interaction between the immune system and the toxicant- or occupational injury-induced gliosis. Specifically, the role of occupational injuries, e.g., trips, slips, and falls resulting in traumatic brain injury, and occupational toxicants, e.g., volatile organic compounds, metals, and nanoparticles/nanomaterials in the development of neuroinflammation and neurological or neurodegenerative diseases are highlighted. Further, this review recapitulates the recent advancement related to the characterization of the molecular mechanisms comprising protein phosphorylation and cell signaling, culminating in neuroinflammation.
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Vakrakou AG, Paschalidis N, Pavlos E, Giannouli C, Karathanasis D, Tsipota X, Velonakis G, Stadelmann-Nessler C, Evangelopoulos ME, Stefanis L, Kilidireas C. Specific myeloid signatures in peripheral blood differentiate active and rare clinical phenotypes of multiple sclerosis. Front Immunol 2023; 14:1071623. [PMID: 36761741 PMCID: PMC9905713 DOI: 10.3389/fimmu.2023.1071623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 01/03/2023] [Indexed: 01/26/2023] Open
Abstract
Current understanding of Multiple Sclerosis (MS) pathophysiology implicates perturbations in adaptive cellular immune responses, predominantly T cells, in Relapsing-Remitting forms (RRMS). Nevertheless, from a clinical perspective MS is a heterogeneous disease reflecting the heterogeneity of involved biological systems. This complexity requires advanced analysis tools at the single-cell level to discover biomarkers for better patient-group stratification. We designed a novel 44-parameter mass cytometry panel to interrogate predominantly the role of effector and regulatory subpopulations of peripheral blood myeloid subsets along with B and T-cells (excluding granulocytes) in MS, assessing three different patient cohorts: RRMS, PPMS (Primary Progressive) and Tumefactive MS patients (TMS) (n=10, 8, 14 respectively). We further subgrouped our cohort into inactive or active disease stages to capture the early underlying events in disease pathophysiology. Peripheral blood analysis showed that TMS cases belonged to the spectrum of RRMS, whereas PPMS cases displayed different features. In particular, TMS patients during a relapse stage were characterized by a specific subset of CD11c+CD14+ CD33+, CD192+, CD172+-myeloid cells with an alternative phenotype of monocyte-derived macrophages (high arginase-1, CD38, HLA-DR-low and endogenous TNF-a production). Moreover, TMS patients in relapse displayed a selective CD4 T-cell lymphopenia of cells with a Th2-like polarised phenotype. PPMS patients did not display substantial differences from healthy controls, apart from a trend toward higher expansion of NK cell subsets. Importantly, we found that myeloid cell populations are reshaped under effective disease-modifying therapy predominantly with glatiramer acetate and to a lesser extent with anti-CD20, suggesting that the identified cell signature represents a specific therapeutic target in TMS. The expanded myeloid signature in TMS patients was also confirmed by flow cytometry. Serum neurofilament light-chain levels confirmed the correlation of this myeloid cell signature with indices of axonal injury. More in-depth analysis of myeloid subsets revealed an increase of a subset of highly cytolytic and terminally differentiated NK cells in PPMS patients with leptomeningeal enhancement (active-PPMS), compared to those without (inactive-PPMS). We have identified previously uncharacterized subsets of circulating myeloid cells and shown them to correlate with distinct disease forms of MS as well as with specific disease states (relapse/remission).
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Affiliation(s)
- Aigli G Vakrakou
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Department of Neuropathology, University of Göttingen Medical Center, Göttingen, Germany
| | - Nikolaos Paschalidis
- Mass Cytometry-CyTOF Laboratory, Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Eleftherios Pavlos
- Center for Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,Division of Basic Sciences, University of Crete Medical School, Heraklion, Greece
| | - Christina Giannouli
- Center for Clinical Research, Experimental Surgery and Translational Research Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Dimitris Karathanasis
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Xristina Tsipota
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Velonakis
- Research Unit of Radiology, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Maria-Eleftheria Evangelopoulos
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Leonidas Stefanis
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Kilidireas
- Demyelinating Diseases Unit, 1st Department of Neurology, School of Medicine, Aeginition Hospital, National and Kapodistrian University of Athens, Athens, Greece.,Department of Neurology, Henry Dunant Hospital Center, Athens, Greece
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11
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Differential compartmentalization of myeloid cell phenotypes and responses towards the CNS in Alzheimer's disease. Nat Commun 2022; 13:7210. [PMID: 36418303 PMCID: PMC9684147 DOI: 10.1038/s41467-022-34719-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 11/01/2022] [Indexed: 11/27/2022] Open
Abstract
Myeloid cells are suggested as an important player in Alzheimer´s disease (AD). However, its continuum of phenotypic and functional changes across different body compartments and their use as a biomarker in AD remains elusive. Here, we perform multiple state-of-the-art analyses to phenotypically and metabolically characterize immune cells between peripheral blood (n = 117), cerebrospinal fluid (CSF, n = 117), choroid plexus (CP, n = 13) and brain parenchyma (n = 13). We find that CSF cells increase expression of markers involved in inflammation, phagocytosis, and metabolism. Changes in phenotype of myeloid cells from AD patients are more pronounced in CP and brain parenchyma and upon in vitro stimulation, suggesting that AD-myeloid cells are more vulnerable to environmental changes. Our findings underscore the importance of myeloid cells in AD and the detailed characterization across body compartments may serve as a resource for future studies focusing on the assessment of these cells as biomarkers in AD.
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12
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Yong VW. Microglia in multiple sclerosis: Protectors turn destroyers. Neuron 2022; 110:3534-3548. [PMID: 35882229 DOI: 10.1016/j.neuron.2022.06.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/15/2022] [Accepted: 06/27/2022] [Indexed: 12/15/2022]
Abstract
Microglia are implicated in all stages of multiple sclerosis (MS). Microglia alterations are detected by positron emission tomography in people living with MS prior to the formation of structural lesions determined through magnetic resonance imaging. In histological specimens, clusters of microglia form in normal-appearing tissue likely predating the development of lesions. Features of degeneration-associated/pro-inflammatory states of microglia increase with chronicity of MS. However, microglia play many beneficial roles including the removal of neurotoxins and in fostering repair. The protector-gone-rogue microglia in MS is featured herein. We consider mechanisms of microglia neurotoxicity and discuss factors, including aging, osteopontin, and iron metabolism, that cause microglia to lose their protective states and become injurious. We evaluate medications to affect microglia in MS, such as the emerging class of Bruton's tyrosine kinase inhibitors. The framework of microglia-turned-destroyers may instigate new approaches to counter microglia-driven neurodegeneration in MS.
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Affiliation(s)
- V Wee Yong
- Hotchkiss Brain Institute and the Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada.
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13
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Liu Z, Xun J, Liu S, Wang B, Zhang A, Zhang L, Wang X, Zhang Q. Imaging mass cytometry: High-dimensional and single-cell perspectives on the microenvironment of solid tumours. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 175:140-146. [DOI: 10.1016/j.pbiomolbio.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 01/04/2023]
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14
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Single-Cell Analysis to Better Understand the Mechanisms Involved in MS. Int J Mol Sci 2022; 23:ijms232012142. [PMID: 36292995 PMCID: PMC9602568 DOI: 10.3390/ijms232012142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/01/2022] [Accepted: 10/03/2022] [Indexed: 11/17/2022] Open
Abstract
Multiple sclerosis is a chronic and inflammatory disease of the central nervous system. Although this disease is widely studied, many of the precise mechanisms involved are still not well known. Numerous studies currently focusing on multiple sclerosis highlight the involvement of many major immune cell subsets, such as CD4+ T cells, CD8+ T cells and more recently B cells. However, our vision of its pathology has remained too broad to allow the proper use of targeted therapeutics. This past decade, new technologies have emerged, enabling deeper research into the different cell subsets at the single-cell level both in the periphery and in the central nervous system. These technologies could allow us to identify new cell populations involved in the disease process and new therapeutic targets. In this review, we briefly introduce the major single-cell technologies currently used in studies before diving into the major findings from the multiple sclerosis research from the past 5 years. We focus on results that were obtained using single-cell technologies to study immune cells and cells from the central nervous system.
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15
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Abstract
PURPOSE OF REVIEW Microglia normally protects the central nervous system (CNS) against insults. However, their persistent activation in multiple sclerosis (MS) contributes to injury. Here, we review microglia activation in MS and their detection using positron emission tomography (PET). RECENT FINDINGS During lesion evolution and the progression of MS, microglia activity may contribute to neurotoxicity through the release of pro-inflammatory cytokines, reactive oxidative species, proteases and glutamate. A means to detect and monitor microglia activation in individuals living with MS is provided by positron emission tomography (PET) imaging using the mitochondrial 18-kDa translocator protein (TSPO) ligand. TSPO PET imaging shows increased microglial activation within the normal appearing white matter that precedes radiological signs of neurodegeneration measured by T2 lesion enlargement. PET-detected microglia activation increases with progression of MS. These findings demand the use of CNS penetrant inhibitors that affect microglia. Such therapies may include hydroxychloroquine that is recently reported in a small study to reduce the expected progression in primary progressive MS, and Bruton's tyrosine kinase inhibitors for which there are now eleven Phase 3 registered trials in MS. SUMMARY Microglial activation drives injury in MS. PET imaging with microglia-specific ligands offer new insights into progression of MS and as a monitor for treatment responses.
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16
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Elkjaer ML, Röttger R, Baumbach J, Illes Z. A Systematic Review of Tissue and Single Cell Transcriptome/Proteome Studies of the Brain in Multiple Sclerosis. Front Immunol 2022; 13:761225. [PMID: 35309325 PMCID: PMC8924618 DOI: 10.3389/fimmu.2022.761225] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/28/2022] [Indexed: 11/27/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating and degenerative disease of the central nervous system (CNS). Although inflammatory responses are efficiently treated, therapies for progression are scarce and suboptimal, and biomarkers to predict the disease course are insufficient. Cure or preventive measures for MS require knowledge of core pathological events at the site of the tissue damage. Novelties in systems biology have emerged and paved the way for a more fine-grained understanding of key pathological pathways within the CNS, but they have also raised questions still without answers. Here, we systemically review the power of tissue and single-cell/nucleus CNS omics and discuss major gaps of integration into the clinical practice. Systemic search identified 49 transcriptome and 11 proteome studies of the CNS from 1997 till October 2021. Pioneering molecular discoveries indicate that MS affects the whole brain and all resident cell types. Despite inconsistency of results, studies imply increase in transcripts/proteins of semaphorins, heat shock proteins, myelin proteins, apolipoproteins and HLAs. Different lesions are characterized by distinct astrocytic and microglial polarization, altered oligodendrogenesis, and changes in specific neuronal subtypes. In all white matter lesion types, CXCL12, SCD, CD163 are highly expressed, and STAT6- and TGFβ-signaling are increased. In the grey matter lesions, TNF-signaling seems to drive cell death, and especially CUX2-expressing neurons may be susceptible to neurodegeneration. The vast heterogeneity at both cellular and lesional levels may underlie the clinical heterogeneity of MS, and it may be more complex than the current disease phenotyping in the clinical practice. Systems biology has not solved the mystery of MS, but it has discovered multiple molecules and networks potentially contributing to the pathogenesis. However, these results are mostly descriptive; focused functional studies of the molecular changes may open up for a better interpretation. Guidelines for acceptable quality or awareness of results from low quality data, and standardized computational and biological pipelines may help to overcome limited tissue availability and the “snap shot” problem of omics. These may help in identifying core pathological events and point in directions for focus in clinical prevention.
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Affiliation(s)
- Maria L Elkjaer
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Richard Röttger
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Jan Baumbach
- Chair of Computational Systems Biology, University of Hamburg, Hamburg, Germany
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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17
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Rosmus DD, Lange C, Ludwig F, Ajami B, Wieghofer P. The Role of Osteopontin in Microglia Biology: Current Concepts and Future Perspectives. Biomedicines 2022; 10:biomedicines10040840. [PMID: 35453590 PMCID: PMC9027630 DOI: 10.3390/biomedicines10040840] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 12/14/2022] Open
Abstract
The innate immune landscape of the central nervous system (CNS), including the brain and the retina, consists of different myeloid cell populations with distinct tasks to fulfill. Whereas the CNS borders harbor extraparenchymal CNS-associated macrophages whose main duty is to build up a defense against invading pathogens and other damaging factors from the periphery, the resident immune cells of the CNS parenchyma and the retina, microglia, are highly dynamic cells with a plethora of functions during homeostasis and disease. Therefore, microglia are constantly sensing their environment and closely interacting with surrounding cells, which is in part mediated by soluble factors. One of these factors is Osteopontin (OPN), a multifunctional protein that is produced by different cell types in the CNS, including microglia, and is upregulated in neurodegenerative and neuroinflammatory conditions. In this review, we discuss the current literature about the interaction between microglia and OPN in homeostasis and several disease entities, including multiple sclerosis (MS), Alzheimer’s and cerebrovascular diseases (AD, CVD), amyotrophic lateral sclerosis (ALS), age-related macular degeneration (AMD) and diabetic retinopathy (DR), in the context of the molecular pathways involved in OPN signaling shaping the function of microglia. As nearly all CNS diseases are characterized by pathological alterations in microglial cells, accompanied by the disturbance of the homeostatic microglia phenotype, the emergence of disease-associated microglia (DAM) states and their interplay with factors shaping the DAM-signature, such as OPN, is of great interest for therapeutical interventions in the future.
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Affiliation(s)
| | - Clemens Lange
- Eye Center, Freiburg Medical Center, University of Freiburg, 79106 Freiburg, Germany; (C.L.); (F.L.)
- Ophtha-Lab, Department of Ophthalmology, St. Franziskus Hospital, 48145 Muenster, Germany
| | - Franziska Ludwig
- Eye Center, Freiburg Medical Center, University of Freiburg, 79106 Freiburg, Germany; (C.L.); (F.L.)
| | - Bahareh Ajami
- Department of Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA;
| | - Peter Wieghofer
- Institute of Anatomy, Leipzig University, 04103 Leipzig, Germany;
- Cellular Neuroanatomy, Institute of Theoretical Medicine, Medical Faculty, Augsburg University, 86159 Augsburg, Germany
- Correspondence:
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18
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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: 39] [Impact Index Per Article: 19.5] [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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19
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Hamner MA, McDonough A, Gong DC, Todd LJ, Rojas G, Hodecker S, Ransom CB, Reh TA, Ransom BR, Weinstein JR. Microglial depletion abolishes ischemic preconditioning in white matter. Glia 2021; 70:661-674. [PMID: 34939240 DOI: 10.1002/glia.24132] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 01/17/2023]
Abstract
Ischemic preconditioning (IPC) is a phenomenon whereby a brief, non-injurious ischemic exposure enhances tolerance to a subsequent ischemic challenge. The mechanism of IPC has mainly been studied in rodent stroke models where gray matter (GM) constitutes about 85% of the cerebrum. In humans, white matter (WM) is 50% of cerebral volume and is a critical component of stroke damage. We developed a novel CNS WM IPC model using the mouse optic nerve (MON) and identified the involved immune signaling pathways. Here we tested the hypothesis that microglia are necessary for WM IPC. Microglia were depleted by treatment with the colony stimulating factor 1 receptor (CSF1R) inhibitor PLX5622. MONs were exposed to transient ischemia in vivo, acutely isolated 72 h later, and subjected to oxygen-glucose deprivation (OGD) to simulate a severe ischemic injury (i.e., stroke). Functional and structural axonal recovery was assessed by recording compound action potentials (CAPs) and by microscopy using quantitative stereology. Microglia depletion eliminated IPC-mediated protection. In control mice, CAP recovery was improved in preconditioned MONs compared with non-preconditioned MONs, however, in PLX5622-treated mice, we observed no difference in CAP recovery between preconditioned and non-preconditioned MONs. Microgliadepletion also abolished IPC protective effects on axonal integrity and survival of mature (APC+ ) oligodendrocytes after OGD. IPC-mediated protection was independent of retinal injury suggesting it results from mechanistic processes intrinsic to ischemia-exposed WM. We conclude that preconditioned microglia are critical for IPC in WM. The "preconditioned microglia" phenotype might protect against other CNS pathologies and is a neurotherapeutic horizon worth exploring.
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Affiliation(s)
- Margaret A Hamner
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Ashley McDonough
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Davin C Gong
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Levi J Todd
- Department of Biological Structure, School of Medicine, University of Washington, Seattle, Washington, USA
| | - German Rojas
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Sibylle Hodecker
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Christopher B Ransom
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Thomas A Reh
- Department of Biological Structure, School of Medicine, University of Washington, Seattle, Washington, USA
| | - Bruce R Ransom
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA.,Neuroscience Department, City University of Hong Kong, Kowloon, Hong Kong
| | - Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington, USA.,Department of Neurological Surgery, School of Medicine, University of Washington, Seattle, Washington, USA
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20
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Mechanism-based criteria to improve therapeutic outcomes in progressive multiple sclerosis. Nat Rev Neurol 2021; 18:40-55. [PMID: 34732831 DOI: 10.1038/s41582-021-00581-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 02/07/2023]
Abstract
In contrast to the multiple disease-modifying therapies that are available for relapsing-remitting multiple sclerosis (MS), the therapeutic options for progressive MS (PMS) are limited. Recent advances in our understanding of the neuroimmunology of PMS, including the mechanisms that drive slowly expanding lesions, have fuelled optimism for improved treatment of this condition. In this Review, we highlight the commonly observed neuropathology of PMS and discuss the associated mechanisms of CNS injury. We then apply this knowledge to formulate criteria for therapeutic efficacy in PMS, beginning with the need for early treatment owing to the substantial neuropathology that is already present at the initial clinical presentation. Other requirements include: antagonism of neuroaxonal injury mediators such as pro-inflammatory microglia and lymphocytes; remediation of oxidative stress resulting from iron deposition and mitochondrial dysfunction; and promotion of neuroprotection through remyelination. We consider whether current disease-modifying therapies for relapsing-remitting MS meet the criteria for successful therapeutics in PMS and suggest that the evidence favours the early introduction of sphingosine 1-phosphate receptor modulators. Finally, we weigh up emerging medications, including repurposed generic medications and Bruton's tyrosine kinase inhibitors, against these fundamental criteria. In this new therapeutic era in PMS, success depends collectively on understanding disease mechanisms, drug characteristics (including brain penetration) and rational use.
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21
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Hou Y, Yang D, Wang X, Wang H, Zhang H, Wang P, Liu Y, Gao X, Yang J, Wu C. Pseudoginsenoside-F11 promotes functional recovery after transient cerebral ischemia by regulating the microglia/macrophage polarization in rats. Int Immunopharmacol 2021; 99:107896. [PMID: 34246061 DOI: 10.1016/j.intimp.2021.107896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/01/2021] [Accepted: 06/13/2021] [Indexed: 02/06/2023]
Abstract
The polarization of microglia/macrophages after cerebral ischemia is critical for post-stroke damage/recovery. Previously, we found that pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, has neuroprotective effects on permanent and transient cerebral ischemia in rats. This study aimed to investigate the effects and potential mechanisms of PF11 on microglia/macrophage polarization following transient cerebral ischemia in rats. In vivo data showed that oral administration of PF11 (12 mg/kg) significantly attenuated cognitive deficits and sensorimotor dysfunction, infarct volume and brain edema in transient middle cerebral artery occlusion (tMCAO)-treated rats, as well as reduced the loss of neurons and the over-activation of microglia in penumbra of ipsilateral striatum and cortex. Notably, the proportion of M2 microglia/macrophages in the total activated microglia/macrophages peaked on day 14 after tMCAO in rats, while PF11 promoted its peak advancing to day 3 post-tMCAO, which allowing the damaged brain to enter the repair period more quickly. Furthermore, PF11 increased the expression of anti-inflammatory markers and decreased the expression of pro-inflammatory markers in ipsilateral striatum and cortex. In addition, in vitro data showed that PF11 inhibited the induction of M1 microglia by oxygen glucose deprivation/re-oxygenation (OGD/R)-induced neurons, and promoted the polarization of microglia to M2 phenotype in a Jumonji domain-containing protein 3 (Jmjd3)-dependent manner. Moreover, PF11 promoted the protection of M2 microglia and attenuated the exacerbation of M1 microglia on OGD/R-induced neuronal damage. Taken together, these results indicate that PF11 protects ischemic neurons by promoting M2 microglia/macrophage polarization in a Jmjd3-dependent manner, ultimately facilitating the functional recovery following transient cerebral ischemia.
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Affiliation(s)
- Ying Hou
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Depeng Yang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Xianshi Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Huiyang Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Haotian Zhang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Pengwei Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Yinglu Liu
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Xiaoyun Gao
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China
| | - Jingyu Yang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China.
| | - Chunfu Wu
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, PR China.
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22
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Muzio L, Viotti A, Martino G. Microglia in Neuroinflammation and Neurodegeneration: From Understanding to Therapy. Front Neurosci 2021; 15:742065. [PMID: 34630027 PMCID: PMC8497816 DOI: 10.3389/fnins.2021.742065] [Citation(s) in RCA: 174] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 12/19/2022] Open
Abstract
Microglia are the resident macrophages of the central nervous system (CNS) acting as the first line of defense in the brain by phagocytosing harmful pathogens and cellular debris. Microglia emerge from early erythromyeloid progenitors of the yolk sac and enter the developing brain before the establishment of a fully mature blood-brain barrier. In physiological conditions, during brain development, microglia contribute to CNS homeostasis by supporting cell proliferation of neural precursors. In post-natal life, such cells contribute to preserving the integrity of neuronal circuits by sculpting synapses. After a CNS injury, microglia change their morphology and down-regulate those genes supporting homeostatic functions. However, it is still unclear whether such changes are accompanied by molecular and functional modifications that might contribute to the pathological process. While comprehensive transcriptome analyses at the single-cell level have identified specific gene perturbations occurring in the "pathological" microglia, still the precise protective/detrimental role of microglia in neurological disorders is far from being fully elucidated. In this review, the results so far obtained regarding the role of microglia in neurodegenerative disorders will be discussed. There is solid and sound evidence suggesting that regulating microglia functions during disease pathology might represent a strategy to develop future therapies aimed at counteracting brain degeneration in multiple sclerosis, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Luca Muzio
- Neuroimmunology Unit, Division of Neuroscience, IRCCS San Raffaele Hospital, Vita-Salute San Raffaele University, Milan, Italy
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23
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Couloume L, Michel L. New concepts on immunology of Multiple Sclerosis. Presse Med 2021; 50:104072. [PMID: 34547375 DOI: 10.1016/j.lpm.2021.104072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/15/2021] [Accepted: 09/14/2021] [Indexed: 12/27/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory and immune-driven demyelinating disease of the central nervous system (CNS). During the past decade, major advances have been made to understand the development of MS as well as its progressive stage. Here, we discuss some emerging concepts on immunology of MS, including the growing interest in the involvement of gut microbiota and the recent pathological concepts on the progression phase. Finally, we present some immuno-tools recently available that contribute to better understand diversity and function of the immune system.
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Affiliation(s)
| | - Laure Michel
- Univ Rennes, CHU Rennes, Neurology, Inserm, CIC 1414 (Centre d'Investigation Clinique de Rennes), F-35000 Rennes, France; Unité Mixte de Recherche (UMR) S1236, INSERM, University of Rennes, Etablissement Français du Sang, Rennes, France; Suivi Immunologique des Thérapeutiques Innovantes, Centre Hospitalier Universitaire de Rennes, Etablissement Français du Sang, Rennes, France.
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24
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Xiao X, Qiao Y, Jiao Y, Fu N, Yang W, Wang L, Yu R, Han J. Dice-XMBD: Deep Learning-Based Cell Segmentation for Imaging Mass Cytometry. Front Genet 2021; 12:721229. [PMID: 34603385 PMCID: PMC8480472 DOI: 10.3389/fgene.2021.721229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/30/2021] [Indexed: 12/21/2022] Open
Abstract
Highly multiplexed imaging technology is a powerful tool to facilitate understanding the composition and interactions of cells in tumor microenvironments at subcellular resolution, which is crucial for both basic research and clinical applications. Imaging mass cytometry (IMC), a multiplex imaging method recently introduced, can measure up to 100 markers simultaneously in one tissue section by using a high-resolution laser with a mass cytometer. However, due to its high resolution and large number of channels, how to process and interpret the image data from IMC remains a key challenge to its further applications. Accurate and reliable single cell segmentation is the first and a critical step to process IMC image data. Unfortunately, existing segmentation pipelines either produce inaccurate cell segmentation results or require manual annotation, which is very time consuming. Here, we developed Dice-XMBD, a Deep learnIng-based Cell sEgmentation algorithm for tissue multiplexed imaging data. In comparison with other state-of-the-art cell segmentation methods currently used for IMC images, Dice-XMBD generates more accurate single cell masks efficiently on IMC images produced with different nuclear, membrane, and cytoplasm markers. All codes and datasets are available at https://github.com/xmuyulab/Dice-XMBD.
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Affiliation(s)
- Xu Xiao
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
- National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China
| | - Ying Qiao
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
| | - Yudi Jiao
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
| | - Na Fu
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
| | | | - Liansheng Wang
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
| | - Rongshan Yu
- Department of Computer Science, School of Informatics, Xiamen University, Xiamen, China
- National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China
- Aginome Scientific, Xiamen, China
| | - Jiahuai Han
- National Institute for Data Science in Health and Medicine, Xiamen University, Xiamen, China
- School of Medicine, Xiamen University, Xiamen, China
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25
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Mitchell D, Shireman J, Sierra Potchanant EA, Lara-Velazquez M, Dey M. Neuroinflammation in Autoimmune Disease and Primary Brain Tumors: The Quest for Striking the Right Balance. Front Cell Neurosci 2021; 15:716947. [PMID: 34483843 PMCID: PMC8414998 DOI: 10.3389/fncel.2021.716947] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 07/26/2021] [Indexed: 12/25/2022] Open
Abstract
According to classical dogma, the central nervous system (CNS) is defined as an immune privileged space. The basis of this theory was rooted in an incomplete understanding of the CNS microenvironment, however, recent advances such as the identification of resident dendritic cells (DC) in the brain and the presence of CNS lymphatics have deepened our understanding of the neuro-immune axis and revolutionized the field of neuroimmunology. It is now understood that many pathological conditions induce an immune response in the CNS, and that in many ways, the CNS is an immunologically distinct organ. Hyperactivity of neuro-immune axis can lead to primary neuroinflammatory diseases such as multiple sclerosis and antibody-mediated encephalitis, whereas immunosuppressive mechanisms promote the development and survival of primary brain tumors. On the therapeutic front, attempts are being made to target CNS pathologies using various forms of immunotherapy. One of the most actively investigated areas of CNS immunotherapy is for the treatment of glioblastoma (GBM), the most common primary brain tumor in adults. In this review, we provide an up to date overview of the neuro-immune axis in steady state and discuss the mechanisms underlying neuroinflammation in autoimmune neuroinflammatory disease as well as in the development and progression of brain tumors. In addition, we detail the current understanding of the interactions that characterize the primary brain tumor microenvironment and the implications of the neuro-immune axis on the development of successful therapeutic strategies for the treatment of CNS malignancies.
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Affiliation(s)
- Dana Mitchell
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Jack Shireman
- Dey Malignant Brain Tumor Laboratory, Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | | | - Montserrat Lara-Velazquez
- Dey Malignant Brain Tumor Laboratory, Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Mahua Dey
- Dey Malignant Brain Tumor Laboratory, Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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26
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Current tools to interrogate microglial biology. Neuron 2021; 109:2805-2819. [PMID: 34390649 DOI: 10.1016/j.neuron.2021.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/23/2021] [Accepted: 07/06/2021] [Indexed: 12/26/2022]
Abstract
Microglial cells perform a plethora of functions in the central nervous system (CNS), involving them in brain development, maintenance of homeostasis in adulthood, and CNS diseases. Significant technical advancements have prompted the development of novel systems adapted to analyze microglia with increasing specificity and intricacy. The advent of single-cell technologies combined with targeted mouse models has been decisive in deciphering microglia heterogeneity and dissecting microglial functions. However sophisticated these tools have become, clear limitations remain. Understanding their pitfalls and advantages ensures their correct application. Therefore, we provide a guide to the cutting-edge methods currently available to dissect microglial biology.
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27
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Beaino W, Janssen B, Vugts DJ, de Vries HE, Windhorst AD. Towards PET imaging of the dynamic phenotypes of microglia. Clin Exp Immunol 2021; 206:282-300. [PMID: 34331705 PMCID: PMC8561701 DOI: 10.1111/cei.13649] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
There is increasing evidence showing the heterogeneity of microglia activation in neuroinflammatory and neurodegenerative diseases. It has been hypothesized that pro‐inflammatory microglia are detrimental and contribute to disease progression, while anti‐inflammatory microglia play a role in damage repair and remission. The development of therapeutics targeting the deleterious glial activity and modulating it into a regenerative phenotype relies heavily upon a clearer understanding of the microglia dynamics during disease progression and the ability to monitor therapeutic outcome in vivo. To that end, molecular imaging techniques are required to assess microglia dynamics and study their role in disease progression as well as to evaluate the outcome of therapeutic interventions. Positron emission tomography (PET) is such a molecular imaging technique, and provides unique capabilities for non‐invasive quantification of neuroinflammation and has the potential to discriminate between microglia phenotypes and define their role in the disease process. However, several obstacles limit the possibility for selective in vivo imaging of microglia phenotypes mainly related to the poor characterization of specific targets that distinguish the two ends of the microglia activation spectrum and lack of suitable tracers. PET tracers targeting translocator protein 18 kDa (TSPO) have been extensively explored, but despite the success in evaluating neuroinflammation they failed to discriminate between microglia activation statuses. In this review, we highlight the current knowledge on the microglia phenotypes in the major neuroinflammatory and neurodegenerative diseases. We also discuss the current and emerging PET imaging targets, the tracers and their potential in discriminating between the pro‐ and anti‐inflammatory microglia activation states.
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Affiliation(s)
- Wissam Beaino
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Bieneke Janssen
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Danielle J Vugts
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Helga E de Vries
- Department of Molecular Cell Biology and Immunology, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, Tracer Center Amsterdam, Amsterdam UMC, Vrije Universiteit, Amsterdam, the Netherlands
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28
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Brockman AA, Mobley BC, Ihrie RA. Histological Studies of the Ventricular-Subventricular Zone as Neural Stem Cell and Glioma Stem Cell Niche. J Histochem Cytochem 2021; 69:819-834. [PMID: 34310246 DOI: 10.1369/00221554211032003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The neural stem cell niche of the ventricular-subventricular zone supports the persistence of stem and progenitor cells in the mature brain. This niche has many notable cytoarchitectural features that affect the activity of stem cells and may also support the survival and growth of invading tumor cells. Histochemical studies of the niche have revealed many proteins that, in combination, can help to reveal stem-like cells in the normal or cancer context, although many caveats persist in the quest to consistently identify these cells in the human brain. Here, we explore the complex relationship between the persistent proliferative capacity of the neural stem cell niche and the malignant proliferation of brain tumors, with a special focus on histochemical identification of stem cells and stem-like tumor cells and an eye toward the potential application of high-dimensional imaging approaches to the field.
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Affiliation(s)
- Asa A Brockman
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Bret C Mobley
- Departments of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rebecca A Ihrie
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Departments of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
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29
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Hsiao CC, Sankowski R, Prinz M, Smolders J, Huitinga I, Hamann J. GPCRomics of Homeostatic and Disease-Associated Human Microglia. Front Immunol 2021; 12:674189. [PMID: 34054860 PMCID: PMC8160299 DOI: 10.3389/fimmu.2021.674189] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/22/2021] [Indexed: 12/24/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are critical sensors affecting the state of eukaryotic cells. To get systematic insight into the GPCRome of microglia, we analyzed publicly available RNA-sequencing data of bulk and single cells obtained from human and mouse brains. We identified 17 rhodopsin and adhesion family GPCRs robustly expressed in microglia from human brains, including the homeostasis-associated genes CX3CR1, GPR34, GPR183, P2RY12, P2RY13, and ADGRG1. Expression of these microglial core genes was lost upon culture of isolated cells ex vivo but could be acquired by human induced pluripotent stem cell (iPSC)-derived microglial precursors transplanted into mouse brains. CXCR4 and PTGER4 were higher expressed in subcortical white matter compared to cortical grey matter microglia, and ADGRG1 was downregulated in microglia obtained from normal-appearing white and grey matter tissue of multiple sclerosis (MS) brains. Single-cell RNA sequencing of microglia from active lesions, obtained early during MS, revealed downregulation of homeostasis-associated GPCR genes and upregulation of CXCR4 expression in a small subset of MS-associated lesional microglia. Functional presence of low levels of CXCR4 on human microglia was confirmed using flow cytometry and transwell migration towards SDF-1. Microglia abundantly expressed the GPCR down-stream signaling mediator genes GNAI2 (αi2), GNAS (αs), and GNA13 (α13), the latter particularly in white matter. Drugs against several microglia GPCRs are available to target microglia in brain diseases. In conclusion, transcriptome profiling allowed us to identify expression of GPCRs that may contribute to brain (patho)physiology and have diagnostic and therapeutic potential in human microglia.
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Affiliation(s)
- Cheng-Chih Hsiao
- Department of Experimental Immunology, Amsterdam institute for Infection and Immunity, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Neuroimmunology Research Group, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Roman Sankowski
- Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Faculty of Medicine, 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
| | - Joost Smolders
- Neuroimmunology Research Group, Netherlands Institute for Neuroscience, Amsterdam, Netherlands.,MS Center ErasMS, Departments of Neurology and Immunology, Erasmus Medical Center, Rotterdam, Netherlands
| | - Inge Huitinga
- Neuroimmunology Research Group, Netherlands Institute for Neuroscience, Amsterdam, Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Jörg Hamann
- Department of Experimental Immunology, Amsterdam institute for Infection and Immunity, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Neuroimmunology Research Group, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
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30
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Microglia: The Missing Link to Decipher and Therapeutically Control MS Progression? Int J Mol Sci 2021; 22:ijms22073461. [PMID: 33801644 PMCID: PMC8038003 DOI: 10.3390/ijms22073461] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 12/17/2022] Open
Abstract
Therapeutically controlling chronic progression in multiple sclerosis (MS) remains a major challenge. MS progression is defined as a steady loss of parenchymal and functional integrity of the central nervous system (CNS), occurring independent of relapses or focal, magnetic resonance imaging (MRI)-detectable inflammatory lesions. While it clinically surfaces in primary or secondary progressive MS, it is assumed to be an integral component of MS from the very beginning. The exact mechanisms causing progression are still unknown, although evolving evidence suggests that they may substantially differ from those driving relapse biology. To date, progression is assumed to be caused by an interplay of CNS-resident cells and CNS-trapped hematopoietic cells. On the CNS-resident cell side, microglia that are phenotypically and functionally related to cells of the monocyte/macrophage lineage may play a key role. Microglia function is highly transformable. Depending on their molecular signature, microglia can trigger neurotoxic pathways leading to neurodegeneration, or alternatively exert important roles in promoting neuroprotection, downregulation of inflammation, and stimulation of repair. Accordingly, to understand and to possibly alter the role of microglial activation during MS disease progression may provide a unique opportunity for the development of suitable, more effective therapeutics. This review focuses on the current understanding of the role of microglia during disease progression of MS and discusses possible targets for therapeutic intervention.
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31
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Ivan DC, Walthert S, Berve K, Steudler J, Locatelli G. Dwellers and Trespassers: Mononuclear Phagocytes at the Borders of the Central Nervous System. Front Immunol 2021; 11:609921. [PMID: 33746939 PMCID: PMC7973121 DOI: 10.3389/fimmu.2020.609921] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/29/2020] [Indexed: 01/02/2023] Open
Abstract
The central nervous system (CNS) parenchyma is enclosed and protected by a multilayered system of cellular and acellular barriers, functionally separating glia and neurons from peripheral circulation and blood-borne immune cells. Populating these borders as dynamic observers, CNS-resident macrophages contribute to organ homeostasis. Upon autoimmune, traumatic or neurodegenerative inflammation, these phagocytes start playing additional roles as immune regulators contributing to disease evolution. At the same time, pathological CNS conditions drive the migration and recruitment of blood-borne monocyte-derived cells across distinct local gateways. This invasion process drastically increases border complexity and can lead to parenchymal infiltration of blood-borne phagocytes playing a direct role both in damage and in tissue repair. While recent studies and technical advancements have highlighted the extreme heterogeneity of these resident and CNS-invading cells, both the compartment-specific mechanism of invasion and the functional specification of intruding and resident cells remain unclear. This review illustrates the complexity of mononuclear phagocytes at CNS interfaces, indicating how further studies of CNS border dynamics are crucially needed to shed light on local and systemic regulation of CNS functions and dysfunctions.
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32
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Epigenomic and transcriptomic analysis of chronic inflammatory diseases. Genes Genomics 2021; 43:227-236. [PMID: 33638813 DOI: 10.1007/s13258-021-01045-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022]
Abstract
Chronic inflammatory diseases (CIDs) have complex pathologies that result from aberrant and persistent immune responses. However, the precise triggers and mechanisms remain elusive. An important aspect of CID research focuses on epigenetics modifications, which regulate gene expression and provide a dynamic transcriptional response to inflammation. In recent years, mounting evidence has demonstrated an association between epigenomic and transcriptomic dysregulation and the phenotypes of CIDs. In particular, epigenetic changes at cis-regulatory elements have provided new insights for immune cell-specific alterations that contribute to disease etiology. Furthermore, the advancements in single-cell genomics provide novel solutions to cell type heterogeneity, which has long posed challenges for CID diagnosis and treatment. In this review, we discuss the current state of epigenomics research of CID and the insights derived from single-cell transcriptomic and epigenomic studies.
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33
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Borst K, Prinz M. Deciphering the heterogeneity of myeloid cells during neuroinflammation in the single-cell era. Brain Pathol 2020; 30:1192-1207. [PMID: 33058309 PMCID: PMC8018048 DOI: 10.1111/bpa.12910] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 08/23/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis (MS) is a disabling neuroinflammatory disease, which is little understood and lacks a sufficient therapeutic regimen. Myeloid cells have repeatedly shown to play a pivotal role in the disease progression. During homeostasis, only the CNS‐resident microglia and CNS‐associated macrophages are present in the CNS. Neuroinflammation causes peripheral immune cells to infiltrate the CNS contributing to disease progression and neurological sequelae. The differential involvement of the diverse peripheral and resident myeloid cell subsets to the disease pathogenesis and outcome are highly debated and difficult to assess. However, novel technological advances (new mouse models, single‐cell RNA‐Sequencing, and CYTOF) have improved the depth of immune profiling, which allows the characterization of distinct myeloid subsets. This review provides an overview of current knowledge on the phenotypes and roles of these different myeloid subsets in neuroinflammatory disease and their therapeutic relevance.
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Affiliation(s)
- Katharina Borst
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Marco Prinz
- Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
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34
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Fernández‐Zapata C, Leman JKH, Priller J, Böttcher C. The use and limitations of single-cell mass cytometry for studying human microglia function. Brain Pathol 2020; 30:1178-1191. [PMID: 33058349 PMCID: PMC8018011 DOI: 10.1111/bpa.12909] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 08/23/2020] [Accepted: 10/12/2020] [Indexed: 12/12/2022] Open
Abstract
Microglia, the resident innate immune cells of the central nervous system (CNS), play an important role in brain development and homoeostasis, as well as in neuroinflammatory, neurodegenerative and psychiatric diseases. Studies in animal models have been used to determine the origin and development of microglia, and how these cells alter their transcriptional and phenotypic signatures during CNS pathology. However, little is known about their human counterparts. Recent studies in human brain samples have harnessed the power of multiplexed single-cell technologies such as single-cell RNA sequencing (scRNA-seq) and mass cytometry (cytometry by time-of-flight [CyTOF]) to provide a comprehensive molecular view of human microglia in healthy and diseased brains. CyTOF is a powerful tool to study high-dimensional protein expression of human microglia (huMG) at the single-cell level. This technology widens the possibilities of high-throughput quantification (of over 60 targeted molecules) at a single-cell resolution. CyTOF can be combined with scRNA-seq for comprehensive analysis, as it allows single-cell analysis of post-translational modifications of proteins, which provides insights into cell signalling dynamics in targeted cells. In addition, imaging mass cytometry (IMC) has recently become commercially available, and will be useful for analysing multiple cell types in human brain sections. IMC leverages mass spectrometry to acquire spatial data of cell-cell interactions on tissue sections, using (theoretically) over 40 markers at the same time. In this review, we summarise recent studies of huMG using CyTOF and IMC analyses. The uses and limitations as well as future directions of these technologies are discussed.
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Affiliation(s)
- Camila Fernández‐Zapata
- Department of Neuropsychiatry and Laboratory of Molecular PsychiatryCharité – Universitätsmedizin BerlinBerlinGermany
| | - Julia K. H. Leman
- Department of Neuropsychiatry and Laboratory of Molecular PsychiatryCharité – Universitätsmedizin BerlinBerlinGermany
| | - Josef Priller
- Department of Neuropsychiatry and Laboratory of Molecular PsychiatryCharité – Universitätsmedizin BerlinBerlinGermany
- German Center for Neurodegenerative Diseases (DZNE)BerlinGermany
- UK Dementia Research Institute (DRI)University of EdinburghEdinburghUK
| | - Chotima Böttcher
- Department of Neuropsychiatry and Laboratory of Molecular PsychiatryCharité – Universitätsmedizin BerlinBerlinGermany
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