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Stoolman JS, Grant RA, Poor TA, Weinberg SE, D'Alessandro KB, Tan J, Hu JYS, Zerrer ME, Wood WA, Harding MC, Soni S, Ridge KM, Schumacker PT, Budinger GRS, Chandel NS. Mitochondrial respiration in microglia is essential for response to demyelinating injury but not proliferation. Nat Metab 2024; 6:1492-1504. [PMID: 39048801 DOI: 10.1038/s42255-024-01080-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 06/14/2024] [Indexed: 07/27/2024]
Abstract
Microglia are necessary for central nervous system (CNS) function during development and play roles in ageing, Alzheimer's disease and the response to demyelinating injury1-5. The mitochondrial respiratory chain (RC) is necessary for conventional T cell proliferation6 and macrophage-dependent immune responses7-10. However, whether mitochondrial RC is essential for microglia proliferation or function is not known. We conditionally deleted the mitochondrial complex III subunit Uqcrfs1 (Rieske iron-sulfur polypeptide 1) in the microglia of adult mice to assess the requirement of microglial RC for survival, proliferation and adult CNS function in vivo. Notably, mitochondrial RC function was not required for survival or proliferation of microglia in vivo. RNA sequencing analysis showed that loss of RC function in microglia caused changes in gene expression distinct from aged or disease-associated microglia. Microglia-specific loss of mitochondrial RC function is not sufficient to induce cognitive decline. Amyloid-β plaque coverage decreased and microglial interaction with amyloid-β plaques increased in the hippocampus of 5xFAD mice with mitochondrial RC-deficient microglia. Microglia-specific loss of mitochondrial RC function did impair remyelination following an acute, reversible demyelinating event. Thus, mitochondrial respiration in microglia is dispensable for proliferation but is essential to maintain a proper response to CNS demyelinating injury.
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Affiliation(s)
- Joshua S Stoolman
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Rogan A Grant
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Taylor A Poor
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Samuel E Weinberg
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Karis B D'Alessandro
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jerica Tan
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jennifer Yuan-Shih Hu
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Megan E Zerrer
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Walter A Wood
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Madeline C Harding
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Sahil Soni
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Karen M Ridge
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Paul T Schumacker
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - G R Scott Budinger
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Navdeep S Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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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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3
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Fritze J, Muralidharan C, Stamp E, Ahlenius H. Microglia undergo disease-associated transcriptional activation and CX3C motif chemokine receptor 1 expression regulates neurogenesis in the aged brain. Dev Neurobiol 2024; 84:128-141. [PMID: 38616340 DOI: 10.1002/dneu.22939] [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: 07/31/2023] [Revised: 01/31/2024] [Accepted: 03/16/2024] [Indexed: 04/16/2024]
Abstract
Adult neurogenesis continues throughout life but declines dramatically with age and in neurodegenerative disorders such as Alzheimer's disease. In parallel, microglia become activated resulting in chronic inflammation in the aged brain. A unique type of microglia, suggested to support neurogenesis, exists in the subventricular zone (SVZ), but little is known how they are affected by aging. We analyzed the transcriptome of aging microglia and identified a unique neuroprotective activation profile in aged SVZ microglia, which is partly shared with disease-associated microglia (DAM). CX3C motif chemokine receptor 1 (CX3CR1) is characteristically expressed by brain microglia where it directs migration to targets for phagocytosis. We show that Cx3cr1 expression, as in DAM, is downregulated in old SVZ microglia and that heterozygous Cx3cr1 mice have increased proliferation and neuroblast number in the aged SVZ but not in the dentate gyrus, identifying CX3CR1 signaling as a novel age and brain region-specific regulator of neurogenesis.
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Affiliation(s)
- Jonas Fritze
- Department of Experimental Medical Sciences, Faculty of Medicine, Stem Cells, Aging and Neurodegeneration Group, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund, Sweden
| | - Chandramouli Muralidharan
- Department of Experimental Medical Sciences, Faculty of Medicine, Stem Cells, Aging and Neurodegeneration Group, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund, Sweden
- Department of Experimental Medical Science, Faculty of Medicine, Molecular Neurogenetics Group, Lund University, Lund, Sweden
| | - Eleanor Stamp
- Department of Experimental Medical Sciences, Faculty of Medicine, Stem Cells, Aging and Neurodegeneration Group, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund, Sweden
| | - Henrik Ahlenius
- Department of Experimental Medical Sciences, Faculty of Medicine, Stem Cells, Aging and Neurodegeneration Group, Lund University, Lund, Sweden
- Lund Stem Cell Center, Lund, Sweden
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4
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Dadwal S, Heneka MT. Microglia heterogeneity in health and disease. FEBS Open Bio 2024; 14:217-229. [PMID: 37945346 PMCID: PMC10839410 DOI: 10.1002/2211-5463.13735] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/12/2023] [Accepted: 11/08/2023] [Indexed: 11/12/2023] Open
Abstract
Microglia, the resident immune cells of the central nervous system (CNS), have received significant attention due to their critical roles in maintaining brain homeostasis and mediating cerebral immune responses. Understanding the origin of microglia has been a subject of great interest, and emerging evidence suggests that microglia consist of multiple subpopulations with unique molecular and functional characteristics. These subpopulations of microglia may exhibit specialized roles in response to different environmental cues as in disease conditions. The newfound understanding of microglial heterogeneity has significant implications for elucidating their roles in both physiological and pathological conditions. In the context of disease, microglia have been studied rigorously as they play a very important role in neuroinflammation. Dysregulated microglial activation and function contribute to chronic inflammation. Further exploration of microglial heterogeneity and their interactions with other cell types in the CNS will undoubtedly pave the way to novel therapeutic strategies targeting microglia-mediated pathologies. In this review, we discuss the latest advances in the field of microglia research, focusing specifically on the origin and subpopulations of microglia, the populations of microglia types in the brains of patients with neurodegenerative diseases, and how microglia are regulated in the healthy CNS.
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Affiliation(s)
- Shilauni Dadwal
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
| | - Michael T. Heneka
- Luxembourg Centre for Systems BiomedicineUniversity of LuxembourgBelvalLuxembourg
- Division of Infectious Diseases and ImmunologyUniversity of Massachusetts Medical SchoolWorcesterMAUSA
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5
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Harry GJ. Microglia Colonization Associated with Angiogenesis and Neural Cell Development. ADVANCES IN NEUROBIOLOGY 2024; 37:163-178. [PMID: 39207692 DOI: 10.1007/978-3-031-55529-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The temporal and spatial pattern of microglia colonization of the nervous system implies a role in early stages of organ development including cell proliferation, differentiation, and neurovascularization. As microglia colonize and establish within the developing nervous system, they assume a neural-specific identity and contribute to key developmental events. Their association around blood vessels implicates them in development of the vascular system or vice versa. A similar association has been reported for neural cell proliferation and associated phenotypic shifts and for cell fate differentiation to neuronal or glial phenotypes. These processes are accomplished by phagocytic activities, cell-cell contact relationships, and secretion of various factors. This chapter will present data currently available from studies evaluating the dynamic and interactive nature of these processes throughout the progression of nervous system development.
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Affiliation(s)
- G Jean Harry
- Mechanistic Toxicology Branch, Division of Translational Toxicology, National Institute Environmental Health Sciences, Research Triangle Park, NC, USA.
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6
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Zhu H, Guan A, Liu J, Peng L, Zhang Z, Wang S. Noteworthy perspectives on microglia in neuropsychiatric disorders. J Neuroinflammation 2023; 20:223. [PMID: 37794488 PMCID: PMC10548593 DOI: 10.1186/s12974-023-02901-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/22/2023] [Indexed: 10/06/2023] Open
Abstract
Microglia are so versatile that they not only provide immune surveillance for central nervous system, but participate in neural circuitry development, brain blood vessels formation, blood-brain barrier architecture, and intriguingly, the regulation of emotions and behaviors. Microglia have a profound impact on neuronal survival, brain wiring and synaptic plasticity. As professional phagocytic cells in the brain, they remove dead cell debris and neurotoxic agents via an elaborate mechanism. The functional profile of microglia varies considerately depending on age, gender, disease context and other internal or external environmental factors. Numerous studies have demonstrated a pivotal involvement of microglia in neuropsychiatric disorders, including negative affection, social deficit, compulsive behavior, fear memory, pain and other symptoms associated with major depression disorder, anxiety disorder, autism spectrum disorder and schizophrenia. In this review, we summarized the latest discoveries regarding microglial ontogeny, cell subtypes or state spectrum, biological functions and mechanistic underpinnings of emotional and behavioral disorders. Furthermore, we highlight the potential of microglia-targeted therapies of neuropsychiatric disorders, and propose outstanding questions to be addressed in future research of human microglia.
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Affiliation(s)
- Hongrui Zhu
- Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
| | - Ao Guan
- School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Jiayuan Liu
- Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Li Peng
- Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
| | - Zhi Zhang
- Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
| | - Sheng Wang
- Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
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7
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Tan Z, Guo Y, Shrestha M, Sun D, Gregory-Ksander M, Jakobs TC. Microglia depletion exacerbates retinal ganglion cell loss in a mouse model of glaucoma. Exp Eye Res 2022; 225:109273. [PMID: 36206859 PMCID: PMC10970711 DOI: 10.1016/j.exer.2022.109273] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/09/2022] [Accepted: 09/26/2022] [Indexed: 01/11/2023]
Abstract
To test whether depletion of microglia in the optic nerve head has a beneficial effect on retinal ganglion cell numbers and function, we depleted microglia by oral administration of the CSF1R antagonist PLX5622. Then, ocular hypertension was induced by unilateral injection of magnetic microbeads into the anterior chamber. Visual function was assessed with pattern electroretinography and measurement of the optomotor reflex. Retinal ganglion cell bodies and axons were counted and gene expression patterns in optic nerve head astrocytes were tested on freshly dissociated astrocytes. PLX5622 efficiently depleted microglia in the retina and the optic nerve head, but about 20% of microglia persisted in the myelinated optic nerve proper even after prolonged exposure to the drug. PLX5622 did not affect ganglion cell function by itself. Elevation of the IOP for four weeks led to the expected decrease in visual acuity and pattern ERG amplitude. Microglia ablation did not affect these parameters. Ganglion cell and axon numbers were counted histologically post mortem. Mice in the microglia depletion group showed a moderate but significantly greater loss of ganglion cells than the control group. At four weeks post microbead injection, gene expression patterns in optic nerve head astrocytes are consistent with an A2 (or neuroprotective) pattern. Microglia depletion blunted the up-regulation of A2 genes in astrocytes. In conclusion, microglia depletion is unlikely to protect retinal ganglion cells in early glaucoma.
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Affiliation(s)
- Zizhu Tan
- The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, Shaanxi, 710061, China; Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Yinjie Guo
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA; The Second Xiangya Hospital of Central South University, 139 Middle Renmin Road, Changsha, Hunan, 410011, China
| | - Maleeka Shrestha
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Daniel Sun
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Meredith Gregory-Ksander
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA
| | - Tatjana C Jakobs
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Harvard University School of Medicine, 20 Staniford Street, Boston, MA, 02114, USA.
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8
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Abstract
Microglia are the resident immune cells of the central nervous system. Microglial progenitors are generated in the yolk sac during the early embryonic stage. Once microglia enter the brain primordium, these cells colonize the structure through migration and proliferation during brain development. Microglia account for a minor population among the total cells that constitute the developing cortex, but they can associate with many surrounding neural lineage cells by extending their filopodia and through their broad migration capacity. Of note, microglia change their distribution in a stage-dependent manner in the developing brain: microglia are homogenously distributed in the pallium in the early and late embryonic stages, whereas these cells are transiently absent from the cortical plate (CP) from embryonic day (E) 15 to E16 and colonize the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ). Previous studies have reported that microglia positioned in the VZ/SVZ/IZ play multiple roles in neural lineage cells, such as regulating neurogenesis, cell survival and neuronal circuit formation. In addition to microglial functions in the zones in which microglia are replenished, these cells indirectly contribute to the proper maturation of post-migratory neurons by exiting the CP during the mid-embryonic stage. Overall, microglial time-dependent distributional changes are necessary to provide particular functions that are required in specific regions. This review summarizes recent advances in the understanding of microglial colonization and multifaceted functions in the developing brain, especially focusing on the embryonic stage, and discuss the molecular mechanisms underlying microglial behaviors.
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9
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Hohsfield LA, Najafi AR, Ghorbanian Y, Soni N, Crapser J, Figueroa Velez DX, Jiang S, Royer SE, Kim SJ, Henningfield CM, Anderson A, Gandhi SP, Mortazavi A, Inlay MA, Green KN. Subventricular zone/white matter microglia reconstitute the empty adult microglial niche in a dynamic wave. eLife 2021; 10:66738. [PMID: 34423781 PMCID: PMC8425950 DOI: 10.7554/elife.66738] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/22/2021] [Indexed: 02/06/2023] Open
Abstract
Microglia, the brain’s resident myeloid cells, play central roles in brain defense, homeostasis, and disease. Using a prolonged colony-stimulating factor 1 receptor inhibitor (CSF1Ri) approach, we report an unprecedented level of microglial depletion and establish a model system that achieves an empty microglial niche in the adult brain. We identify a myeloid cell that migrates from the subventricular zone and associated white matter areas. Following CSF1Ri, these amoeboid cells migrate radially and tangentially in a dynamic wave filling the brain in a distinct pattern, to replace the microglial-depleted brain. These repopulating cells are enriched in disease-associated microglia genes and exhibit similar phenotypic and transcriptional profiles to white-matter-associated microglia. Our findings shed light on the overlapping and distinct functional complexity and diversity of myeloid cells of the CNS and provide new insight into repopulating microglia function and dynamics in the mouse brain.
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Affiliation(s)
- Lindsay A Hohsfield
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | - Allison R Najafi
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | - Yasamine Ghorbanian
- Sue and Bill Gross Stem Cell Research Center, Irvine, United States.,Department of Molecular Biology and Biochemistry, Irvine, United States
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | - Joshua Crapser
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | | | - Shan Jiang
- Department of Developmental and Cell Biology, Irvine, United States
| | - Sarah E Royer
- Department of Neurobiology and Behavior, Irvine, United States.,Sue and Bill Gross Stem Cell Research Center, Irvine, United States.,Department of Anatomy and Neurobiology, Irvine, United States
| | - Sung Jin Kim
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | - Caden M Henningfield
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
| | - Aileen Anderson
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States.,Sue and Bill Gross Stem Cell Research Center, Irvine, United States.,Department of Anatomy and Neurobiology, Irvine, United States.,Department of Physical Medicine & Rehabilitation, University of California, Irvine, Irvine, United States
| | - Sunil P Gandhi
- Department of Neurobiology and Behavior, Irvine, United States
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, Irvine, United States
| | - Matthew A Inlay
- Department of Neurobiology and Behavior, Irvine, United States.,Sue and Bill Gross Stem Cell Research Center, Irvine, United States.,Department of Molecular Biology and Biochemistry, Irvine, United States
| | - Kim N Green
- Department of Neurobiology and Behavior, Irvine, United States.,Institute for Memory Impairments and Neurological Disorders, Irvine, United States
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10
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Generation of an Iba1-EGFP Transgenic Rat for the Study of Microglia in an Outbred Rodent Strain. eNeuro 2021; 8:ENEURO.0026-21.2021. [PMID: 34417284 PMCID: PMC8425967 DOI: 10.1523/eneuro.0026-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/06/2021] [Accepted: 08/11/2021] [Indexed: 11/25/2022] Open
Abstract
Neuroscience has been transformed by the ability to genetically modify inbred mice, including the ability to express fluorescent markers specific to cell types or activation states. This approach has been put to particularly good effect in the study of the innate immune cells of the brain, microglia. These specialized macrophages are exceedingly small and complex, but also highly motile and mobile. To date, there have been no tools similar to those in mice available for studying these fundamental cells in the rat brain, and we seek to fill that gap with the generation of the genetically modified Sprague Dawley rat line: SD-Tg(Iba1-EGFP)Mmmc. Using CRISPR-Cas/9 technology, we knocked in EGFP to the promoter of the gene Iba1. With four male and three female founders confirmed by quantitative PCR analysis to have appropriate and specific insertion, we established a breeding colony with at least three generations of backcrosses to obtain stable and reliable Iba1-EGFP expression. The specificity of EGFP expression to microglia was established by flow cytometry for CD45low/CD11b+ cells and by immunohistochemistry. Microglial EGFP expression was detected in neonates and persisted into adulthood. Blood macrophages and monocytes were found to express low levels of EGFP, as expected. Last, we show that EGFP expression is suitable for live imaging of microglia processes in acute brain slices and via intravital two-photon microscopy.
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11
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Miller S, Blanco MJ. Small molecule therapeutics for neuroinflammation-mediated neurodegenerative disorders. RSC Med Chem 2021; 12:871-886. [PMID: 34223157 PMCID: PMC8221257 DOI: 10.1039/d1md00036e] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/30/2021] [Indexed: 12/12/2022] Open
Abstract
Chronically activated microglia and the resulting cascade of neuroinflammatory mechanisms have been postulated to play a critical role in neurodegenerative disorders. Microglia are the main component of the brain's innate immune system and become activated by infection, injury, misfolded proteins or a multitude of other stimuli. Activated microglia release pro-inflammatory and cytotoxic factors that can damage neurons and transform astrocytes to become toxic to neurons as well. Therapeutic approaches aiming to modulate microglia activation may be beneficial to mitigate the progression of inflammatory-mediated neurodegenerative diseases. In this literature review, we provide an overview of recent progress on key microglia targets and discovery of small molecule compounds advancing in clinical trials to minimize neuroinflammation.
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Affiliation(s)
- Silke Miller
- Sage Therapeutics, Inc. 215 First Street Cambridge Massachusetts 02142 USA
| | - Maria-Jesus Blanco
- Sage Therapeutics, Inc. 215 First Street Cambridge Massachusetts 02142 USA
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12
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Geribaldi-Doldán N, Fernández-Ponce C, Quiroz RN, Sánchez-Gomar I, Escorcia LG, Velásquez EP, Quiroz EN. The Role of Microglia in Glioblastoma. Front Oncol 2021; 10:603495. [PMID: 33585220 PMCID: PMC7879977 DOI: 10.3389/fonc.2020.603495] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/24/2020] [Indexed: 12/23/2022] Open
Abstract
Glioblastoma (GB), the most aggressive malignant glioma, is made up of a large percentage of glioma-associated microglia/macrophages (GAM), suggesting that immune cells play an important role in the pathophysiology of GB. Under physiological conditions, microglia, the phagocytes of the central nervous system (CNS), are involved in various processes such as neurogenesis or axonal growth, and the progression of different conditions such as Alzheimer's disease. Through immunohistochemical studies, markers that enhance GB invasiveness have been shown to be expressed in the peritumoral area of the brain, such as Transforming Growth Factor α (TGF-α), Stromal Sell-Derived Factor 1 (SDF1/CXCL12), Sphingosine-1-Phosphate (S1P) and Neurotrophic Factor Derived from the Glial cell line (GDNF), contributing to the increase in tumor mass. Similarly, it has also been described 17 biomarkers that are present in hypoxic periarteriolar HSC niches in bone marrow and in hypoxic periarteriolar GSC niches in glioblastoma. Interestingly, microglia plays an important role in the microenvironment that supports GB progression, being one of the most important focal points in the study of therapeutic targets for the development of new drugs. In this review, we describe the altered signaling pathways in microglia in the context of GB. We also show how microglia interact with glioblastoma cells and the epigenetic mechanisms involved. Regarding the interactions between microglia and neurogenic niches, some authors indicate that glioblastoma stem cells (GSC) are similar to neural stem cells (NSC), common stem cells in the subventricular zone (SVZ), suggesting that this could be the origin of GB. Understanding the similarities between SVZ and the tumor microenvironment could be important to clarify some mechanisms involved in GB malignancy and to support the discovering of new therapeutic targets for the development of more effective glioblastoma treatments.
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Affiliation(s)
- Noelia Geribaldi-Doldán
- Departamento de Anatomía y Embriología Humanas, Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain
- Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA), Cádiz, Spain
| | - Cecilia Fernández-Ponce
- Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA), Cádiz, Spain
- Departamento de Biomedicina, Biotecnología y Salud Pública. Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain
| | - Roberto Navarro Quiroz
- CMCC-Centro de Matemática, Computação e Cognição, Laboratório do Biologia Computacional e Bioinformática–LBCB, Universidade Federal do ABC, Sao Paulo, Brazil
| | - Ismael Sánchez-Gomar
- Instituto de Investigación e Innovación Biomédica de Cádiz (INiBICA), Cádiz, Spain
- Departamento de Biomedicina, Biotecnología y Salud Pública. Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain
| | - Lorena Gómez Escorcia
- Faculty of Basic and Biomedical Sciences, Universidad Simón Bolívar, Barranquilla, Colombia
- Centro de investigación e innovación en Biomoleculas, Care4You, Barranquilla, Colombia
| | | | - Elkin Navarro Quiroz
- Faculty of Basic and Biomedical Sciences, Universidad Simón Bolívar, Barranquilla, Colombia
- Centro de investigación e innovación en Biomoleculas, Care4You, Barranquilla, Colombia
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13
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:51. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
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14
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Stratoulias V, Venero JL, Tremblay MÈ, Joseph B. Microglial subtypes: diversity within the microglial community. EMBO J 2019. [PMID: 31373067 DOI: 10.15252/embj.2019a101997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Microglia are brain-resident macrophages forming the first active immune barrier in the central nervous system. They fulfill multiple functions across development and adulthood and under disease conditions. Current understanding revolves around microglia acquiring distinct phenotypes upon exposure to extrinsic cues in their environment. However, emerging evidence suggests that microglia display differences in their functions that are not exclusively driven by their milieu, rather by the unique properties these cells possess. This microglial intrinsic heterogeneity has been largely overlooked, favoring the prevailing view that microglia are a single-cell type endowed with spectacular plasticity, allowing them to acquire multiple phenotypes and thereby fulfill their numerous functions in health and disease. Here, we review the evidence that microglia might form a community of cells in which each member (or "subtype") displays intrinsic properties and performs unique functions. Distinctive features and functional implications of several microglial subtypes are considered, across contexts of health and disease. Finally, we suggest that microglial subtype categorization shall be based on function and we propose ways for studying them. Hence, we advocate that plasticity (reaction states) and diversity (subtypes) should both be considered when studying the multitasking microglia.
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Affiliation(s)
- Vassilis Stratoulias
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jose Luis Venero
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.,Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Marie-Ève Tremblay
- Department of Molecular Medicine, Université Laval, Quebec, QC, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Quebec, QC, Canada
| | - Bertrand Joseph
- Toxicology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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15
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Stratoulias V, Venero JL, Tremblay M, Joseph B. Microglial subtypes: diversity within the microglial community. EMBO J 2019; 38:e101997. [PMID: 31373067 PMCID: PMC6717890 DOI: 10.15252/embj.2019101997] [Citation(s) in RCA: 324] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/29/2019] [Accepted: 05/03/2019] [Indexed: 12/03/2022] Open
Abstract
Microglia are brain-resident macrophages forming the first active immune barrier in the central nervous system. They fulfill multiple functions across development and adulthood and under disease conditions. Current understanding revolves around microglia acquiring distinct phenotypes upon exposure to extrinsic cues in their environment. However, emerging evidence suggests that microglia display differences in their functions that are not exclusively driven by their milieu, rather by the unique properties these cells possess. This microglial intrinsic heterogeneity has been largely overlooked, favoring the prevailing view that microglia are a single-cell type endowed with spectacular plasticity, allowing them to acquire multiple phenotypes and thereby fulfill their numerous functions in health and disease. Here, we review the evidence that microglia might form a community of cells in which each member (or "subtype") displays intrinsic properties and performs unique functions. Distinctive features and functional implications of several microglial subtypes are considered, across contexts of health and disease. Finally, we suggest that microglial subtype categorization shall be based on function and we propose ways for studying them. Hence, we advocate that plasticity (reaction states) and diversity (subtypes) should both be considered when studying the multitasking microglia.
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Affiliation(s)
- Vassilis Stratoulias
- Toxicology UnitInstitute of Environmental MedicineKarolinska InstitutetStockholmSweden
| | - Jose Luis Venero
- Departamento de Bioquímica y Biología MolecularFacultad de FarmaciaUniversidad de SevillaSevillaSpain
- Instituto de Biomedicina de Sevilla‐Hospital Universitario Virgen del Rocío/CSIC/Universidad de SevillaSevillaSpain
| | - Marie‐Ève Tremblay
- Department of Molecular MedicineUniversité LavalQuebecQCCanada
- Axe NeurosciencesCentre de Recherche du CHU de Québec‐Université LavalQuebecQCCanada
| | - Bertrand Joseph
- Toxicology UnitInstitute of Environmental MedicineKarolinska InstitutetStockholmSweden
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16
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McDonough A, Noor S, Lee RV, Dodge R, Strosnider JS, Shen J, Davidson S, Möller T, Garden GA, Weinstein JR. Ischemic preconditioning induces cortical microglial proliferation and a transcriptomic program of robust cell cycle activation. Glia 2019; 68:76-94. [PMID: 31420975 DOI: 10.1002/glia.23701] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/24/2019] [Accepted: 07/30/2019] [Indexed: 12/14/2022]
Abstract
Ischemic preconditioning (IPC) is an experimental phenomenon in which a subthreshold ischemic insult applied to the brain reduces damage caused by a subsequent more severe ischemic episode. Identifying key molecular and cellular mediators of IPC will provide critical information needed to develop novel therapies for stroke. Here we report that the transcriptomic response of acutely isolated preconditioned cortical microglia is dominated by marked upregulation of genes involved in cell cycle activation and cellular proliferation. Notably, this transcriptional response occurs in the absence of cortical infarction. We employed ex vivo flow cytometry, immunofluorescent microscopy, and quantitative stereology methods on brain tissue to evaluate microglia proliferation following IPC. Using cellular colocalization of microglial (Iba1) and proliferation (Ki67 and BrdU) markers, we observed a localized increase in the number of microglia and proliferating microglia within the preconditioned hemicortex at 72, but not 24, hours post-IPC. Our quantification demonstrated that the IPC-induced increase in total microglia was due entirely to proliferation. Furthermore, microglia in the preconditioned hemisphere had altered morphology and increased soma volumes, indicative of an activated phenotype. Using transgenic mouse models with either fractalkine receptor (CX3CR1)-haploinsufficiency or systemic type I interferon signaling loss, we determined that microglial proliferation after IPC is dependent on fractalkine signaling but independent of type I interferon signaling. These findings suggest there are multiple distinct targetable signaling pathways in microglia, including CX3CR1-dependent proliferation that may be involved in IPC-mediated protection.
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Affiliation(s)
- Ashley McDonough
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Shahani Noor
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Richard V Lee
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Ryan Dodge
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - James S Strosnider
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Jasmine Shen
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Stephanie Davidson
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Thomas Möller
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Gwenn A Garden
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington
| | - Jonathan R Weinstein
- Department of Neurology, School of Medicine, University of Washington, Seattle, Washington.,Department of Neurological Surgery, School of Medicine, University of Washington, Seattle, Washington
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17
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Eyo UB, Wu LJ. Microglia: Lifelong patrolling immune cells of the brain. Prog Neurobiol 2019; 179:101614. [PMID: 31075285 PMCID: PMC6599472 DOI: 10.1016/j.pneurobio.2019.04.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/11/2019] [Accepted: 04/19/2019] [Indexed: 02/02/2023]
Abstract
Microglial cells are the predominant parenchymal immune cell of the brain. Recent evidence suggests that like peripheral immune cells, microglia patrol the brain in health and disease. Reviewing these data, we first examine the evidence that microglia invade the brain mesenchyme early in embryonic development, establish residence therein, proliferate and subsequently maintain their numbers throughout life. We, then, summarize established and novel evidence for microglial process surveillance in the healthy and injured brain. Finally, we discuss emerging evidence for microglial cell body dynamics that challenge existing assumptions of their sessile nature. We conclude that microglia are long-lived immune cells that patrol the brain through both cell body and process movements. This recognition has significant implications for neuroimmune interactions throughout the animal lifespan.
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Affiliation(s)
- Ukpong B Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Center for Brain Immunology and Glia (BIG), University of Virginia, Charlottesville, VA, USA; Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA.
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18
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Smolders SMT, Kessels S, Vangansewinkel T, Rigo JM, Legendre P, Brône B. Microglia: Brain cells on the move. Prog Neurobiol 2019; 178:101612. [PMID: 30954517 DOI: 10.1016/j.pneurobio.2019.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, tremendous progress has been made in understanding the biology of microglia - i.e. the fascinating immigrated resident immune cell population of the central nervous system (CNS). Recent literature reviews have largely dealt with the plentiful functions of microglia in CNS homeostasis, development and pathology, and the influences of sex and the microbiome. In this review, the intriguing aspect of their physical plasticity during CNS development will get specific attention. Microglia move around (mobility) and reshape their processes (motility). Microglial migration into and inside the CNS is most prominent throughout development and consequently most of the data described in this review concern mobility and motility in the changing environment of the developing brain. Here, we first define microglia based on their highly specialized age- and region-dependent gene expression signature and associated functional heterogeneity. Next, we describe their origin, the migration route of immature microglial cells towards the CNS, the mechanisms underlying their invasion of the CNS, and their spatiotemporal localization and surveying behaviour inside the developing CNS. These processes are dependent on microglial mobility and motility which are determined by the microenvironment of the CNS. Therefore, we further zoom in on the changing environment during CNS development. We elaborate on the extracellular matrix and the respective integrin receptors on microglia and we discuss the purinergic and molecular signalling in microglial mobility. In the last section, we discuss the physiological and pathological functions of microglia in which mobility and motility are involved to stress the importance of microglial 'movement'.
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Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium; INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Pascal Legendre
- INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
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19
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Sirerol-Piquer MS, Belenguer G, Morante-Redolat JM, Duart-Abadia P, Perez-Villalba A, Fariñas I. Physiological Interactions between Microglia and Neural Stem Cells in the Adult Subependymal Niche. Neuroscience 2019; 405:77-91. [PMID: 30677487 DOI: 10.1016/j.neuroscience.2019.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 12/31/2022]
Abstract
Microglia are the prototypical innate immune cells of the central nervous system. They constitute a unique type of tissue-resident mononuclear phagocytes which act as glial cells. Elegant experiments in the last few years have revealed the origin, extraordinary molecular diversity, and phenotypic plasticity of these cells and how their potential relates to both immune and non-immune actions in the normal and diseased brain. Microglial cells originate in the yolk sac and colonize the brain during embryogenesis, playing a role in neural development and later in adult brain function. Neurogenesis continues after birth in discrete areas of the mammalian brain sustained by the postnatal persistence of neural stem cells in specific neurogenic niches. Recent data indicate that microglial cells are distinct cellular elements of these neurogenic niches where they regulate different aspects of stem cell biology. Interestingly, microglial and neural stem cells are specified very early in fetal development and persist as self-renewing populations throughout life, suggesting potential life-long interactions between them. We aim at reviewing these interactions in one neurogenic niche, the subependymal zone.
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Affiliation(s)
- Mª Salomé Sirerol-Piquer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Germán Belenguer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - José Manuel Morante-Redolat
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Pere Duart-Abadia
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Ana Perez-Villalba
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Isabel Fariñas
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain.
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20
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Konishi H, Kiyama H, Ueno M. Dual functions of microglia in the formation and refinement of neural circuits during development. Int J Dev Neurosci 2018; 77:18-25. [DOI: 10.1016/j.ijdevneu.2018.09.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/20/2018] [Accepted: 09/30/2018] [Indexed: 12/29/2022] Open
Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and NeuroscienceNagoya University Graduate School of MedicineNagoya466‐8550Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and NeuroscienceNagoya University Graduate School of MedicineNagoya466‐8550Japan
| | - Masaki Ueno
- Department of System Pathology for Neurological DisordersBrain Research InstituteNiigata UniversityNiigata951‐8585Japan
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21
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Matarredona ER, Talaverón R, Pastor AM. Interactions Between Neural Progenitor Cells and Microglia in the Subventricular Zone: Physiological Implications in the Neurogenic Niche and After Implantation in the Injured Brain. Front Cell Neurosci 2018; 12:268. [PMID: 30177874 PMCID: PMC6109750 DOI: 10.3389/fncel.2018.00268] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/02/2018] [Indexed: 12/15/2022] Open
Abstract
The adult subventricular zone (SVZ) of the mammalian brain contains neural progenitor cells (NPCs) that continuously produce neuroblasts throughout life. These neuroblasts migrate towards the olfactory bulb where they differentiate into local interneurons. The neurogenic niche of the SVZ includes, in addition to NPCs and neuroblasts, astrocytes, ependymal cells, blood vessels and the molecules released by these cell types. In the last few years, microglial cells have also been included as a key component of the SVZ neurogenic niche. Microglia in the SVZ display unique phenotypic features, and are more densely populated and activated than in non-neurogenic regions. In this article we will review literature reporting microglia-NPC interactions in the SVZ and the role of this bilateral communication in microglial function and in NPC biology. This interaction can take place through the release of soluble factors, extracellular vesicles or gap junctional communication. In addition, as NPCs are used for cell replacement therapies, they can establish therapeutically relevant crosstalks with host microglia which will also be summarized throughout the article.
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Affiliation(s)
| | - Rocío Talaverón
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Angel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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22
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Hammond TR, Robinton D, Stevens B. Microglia and the Brain: Complementary Partners in Development and Disease. Annu Rev Cell Dev Biol 2018; 34:523-544. [PMID: 30089221 DOI: 10.1146/annurev-cellbio-100616-060509] [Citation(s) in RCA: 187] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An explosion of findings driven by powerful new technologies has expanded our understanding of microglia, the resident immune cells of the central nervous system (CNS). This wave of discoveries has fueled a growing interest in the roles that these cells play in the development of the CNS and in the neuropathology of a diverse array of disorders. In this review, we discuss the crucial roles that microglia play in shaping the brain-from their influence on neurons and glia within the developing CNS to their roles in synaptic maturation and brain wiring-as well as some of the obstacles to overcome when assessing their contributions to normal brain development. Furthermore, we examine how normal developmental functions of microglia are perturbed or remerge in neurodevelopmental and neurodegenerative disease.
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Affiliation(s)
- Timothy R Hammond
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Daisy Robinton
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Beth Stevens
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA; .,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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23
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Abstract
Microglia begin colonizing the developing brain as early as embryonic day 9, prior to the emergence of neurons and other glia. Their ontogeny is also distinct from other central nervous system cells, as they derive from yolk sac hematopoietic progenitors and not neural progenitors. In this review, we feature these unique characteristics of microglia and assess the spatiotemporal similarities between microglia colonization of the central nervous system and embryonic neurogenesis. We also infer to existing evidence for microglia function from embryonic through to postnatal neurodevelopment to postulate roles for microglia in neurogenesis.
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Affiliation(s)
- Chih Kong Tong
- Neuroinflammation Group, Immunology Laboratory, Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
| | - Sharmili Vidyadaran
- Neuroinflammation Group, Immunology Laboratory, Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Malaysia
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24
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Pierre WC, Smith PLP, Londono I, Chemtob S, Mallard C, Lodygensky GA. Neonatal microglia: The cornerstone of brain fate. Brain Behav Immun 2017; 59:333-345. [PMID: 27596692 DOI: 10.1016/j.bbi.2016.08.018] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/30/2016] [Accepted: 08/29/2016] [Indexed: 12/16/2022] Open
Abstract
Microglia, mainly known for their role in innate immunity and modulation of neuroinflammation, play an active role in central nervous system development and homeostasis. Depending on the context and environmental stimuli, microglia adopt a broad spectrum of activation status from pro-inflammatory, associated with neurotoxicity, to anti-inflammatory linked to neuroprotection. Pro-inflammatory microglial activation is a key hallmark of white matter injury in preterm infants and is involved in developmental origin of adult neurological diseases. Characterization of neonatal microglia function in brain development and inflammation has allowed the investigation of promising therapeutic targets with potential long-lasting neuroprotective effects. True prevention of neuro-degenerative diseases might eventually occur as early as the perinatal period.
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Affiliation(s)
- Wyston C Pierre
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de Montréal, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, Québec, Canada
| | - Peter L P Smith
- Perinatal Center, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Irène Londono
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de Montréal, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, Québec, Canada
| | - Sylvain Chemtob
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de Montréal, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, Québec, Canada; Departments of Ophtalmology, Université de Montréal, Montreal, Quebec, Canada; Departments of Pharmacology, Université de Montréal, Montreal, Quebec, Canada
| | - Carina Mallard
- Perinatal Center, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Gregory A Lodygensky
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de Montréal, 3175 Chemin de la Côte-Sainte-Catherine, Montréal, Québec, Canada; Montreal Heart Institute, 5000 Rue Bélanger, Montreal, Quebec, Canada; Department of Neuroscience, Université de Montréal, Montreal, Quebec, Canada; Departments of Pharmacology, Université de Montréal, Montreal, Quebec, Canada.
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25
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Eyo UB, Miner SA, Weiner JA, Dailey ME. Developmental changes in microglial mobilization are independent of apoptosis in the neonatal mouse hippocampus. Brain Behav Immun 2016; 55:49-59. [PMID: 26576723 PMCID: PMC4864211 DOI: 10.1016/j.bbi.2015.11.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/09/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
During CNS development, microglia transform from highly mobile amoeboid-like cells to primitive ramified forms and, finally, to highly branched but relatively stationary cells in maturity. The factors that control developmental changes in microglia are largely unknown. Because microglia detect and clear apoptotic cells, developmental changes in microglia may be controlled by neuronal apoptosis. Here, we assessed the extent to which microglial cell density, morphology, motility, and migration are regulated by developmental apoptosis, focusing on the first postnatal week in the mouse hippocampus when the density of apoptotic bodies peaks at postnatal day 4 and declines sharply thereafter. Analysis of microglial form and distribution in situ over the first postnatal week showed that, although there was little change in the number of primary microglial branches, microglial cell density increased significantly, and microglia were often seen near or engulfing apoptotic bodies. Time-lapse imaging in hippocampal slices harvested at different times over the first postnatal week showed differences in microglial motility and migration that correlated with the density of apoptotic bodies. The extent to which these changes in microglia are driven by developmental neuronal apoptosis was assessed in tissues from BAX null mice lacking apoptosis. We found that apoptosis can lead to local microglial accumulation near apoptotic neurons in the pyramidal cell body layer but, unexpectedly, loss of apoptosis did not alter overall microglial cell density in vivo or microglial motility and migration in ex vivo tissue slices. These results demonstrate that developmental changes in microglial form, distribution, motility, and migration occur essentially normally in the absence of developmental apoptosis, indicating that factors other than neuronal apoptosis regulate these features of microglial development.
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Abstract
UNLABELLED Microglia are involved in synaptic pruning both in development and in the mature CNS. In this study, we investigated whether microglia might further contribute to circuit plasticity by modulating neuronal recruitment from the neurogenic subventricular zone (SVZ) of the adult mouse striatum. We found that microglia residing in the SVZ and adjacent rostral migratory stream (RMS) comprise a morphologically and antigenically distinct phenotype of immune effectors. Whereas exhibiting characteristics of alternatively activated microglia, the SVZ/RMS microglia were clearly distinguished by their low expression of purinoceptors and lack of ATP-elicitable chemotaxis. Furthermore, the in vivo depletion of these microglia hampered the survival and migration of newly generated neuroblasts through the RMS to the olfactory bulb. SVZ and RMS microglia thus appear to comprise a functionally distinct class that is selectively adapted to the support and direction of neuronal integration into the olfactory circuitry. Therefore, this unique microglial subpopulation may serve as a novel target with which to modulate cellular addition from endogenous neural stem and progenitor cells of the adult brain. SIGNIFICANCE STATEMENT Microglial cells are a specialized population of macrophages in the CNS, playing key roles as immune mediators. As integral components in the CNS, the microglia stand out for using the same mechanisms, phagocytosis and cytochemokine release, to promote homeostasis, synaptic pruning, and neural circuitry sculpture. Here, we addressed microglial functions in the subventricular zone (SVZ), the major postnatal neurogenic niche. Our results depict microglia as a conspicuous component of SVZ and its anterior extension, the rostral migratory stream, a pathway used by neuroblasts during their transit toward olfactory bulb layers. In addition to other unique populations residing in the SVZ niche, microglia display distinct morphofunctional properties that boost neuronal progenitor survival and migration in the mammalian brain.
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Rouaux C, Hedin-Pereira C, Costa MR. Editorial: Progenitor diversity and neural cell specification in the central nervous system. Front Cell Neurosci 2015; 9:358. [PMID: 26441529 PMCID: PMC4563242 DOI: 10.3389/fncel.2015.00358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 08/26/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Caroline Rouaux
- Institut National de la Santé et de la Recherche Médical U1118, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg Strasbourg, France
| | - Cecília Hedin-Pereira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Marcos R Costa
- Brain Institute, Federal University of Rio Grande do Norte Natal, Brazil
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