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Barbaresi P, Fabri M, Lorenzi T, Sagrati A, Morroni M. Intrinsic organization of the corpus callosum. Front Physiol 2024; 15:1393000. [PMID: 39035452 PMCID: PMC11259024 DOI: 10.3389/fphys.2024.1393000] [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: 02/28/2024] [Accepted: 05/16/2024] [Indexed: 07/23/2024] Open
Abstract
The corpus callosum-the largest commissural fiber system connecting the two cerebral hemispheres-is considered essential for bilateral sensory integration and higher cognitive functions. Most studies exploring the corpus callosum have examined either the anatomical, physiological, and neurochemical organization of callosal projections or the functional and/or behavioral aspects of the callosal connections after complete/partial callosotomy or callosal lesion. There are no works that address the intrinsic organization of the corpus callosum. We review the existing information on the activities that take place in the commissure in three sections: I) the topographical and neurochemical organization of the intracallosal fibers, II) the role of glia in the corpus callosum, and III) the role of the intracallosal neurons.
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Affiliation(s)
- Paolo Barbaresi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Mara Fabri
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Teresa Lorenzi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Andrea Sagrati
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Manrico Morroni
- Electron Microscopy Unit, Azienda Ospedaliero-Universitaria, Ancona, Italy
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2
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Charrière K, Schneider V, Perrignon-Sommet M, Lizard G, Benani A, Jacquin-Piques A, Vejux A. Exploring the Role of Apigenin in Neuroinflammation: Insights and Implications. Int J Mol Sci 2024; 25:5041. [PMID: 38732259 PMCID: PMC11084463 DOI: 10.3390/ijms25095041] [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: 03/25/2024] [Revised: 05/01/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
Neuroinflammation, a hallmark of various central nervous system disorders, is often associated with oxidative stress and neuronal or oligodendrocyte cell death. It is therefore very interesting to target neuroinflammation pharmacologically. One therapeutic option is the use of nutraceuticals, particularly apigenin. Apigenin is present in plants: vegetables (parsley, celery, onions), fruits (oranges), herbs (chamomile, thyme, oregano, basil), and some beverages (tea, beer, and wine). This review explores the potential of apigenin as an anti-inflammatory agent across diverse neurological conditions (multiple sclerosis, Parkinson's disease, Alzheimer's disease), cancer, cardiovascular diseases, cognitive and memory disorders, and toxicity related to trace metals and other chemicals. Drawing upon major studies, we summarize apigenin's multifaceted effects and underlying mechanisms in neuroinflammation. Our review underscores apigenin's therapeutic promise and calls for further investigation into its clinical applications.
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Affiliation(s)
- Karine Charrière
- Université de Franche-Comté, CHU Besançon, UMR 1322 LINC, INSERM CIC 1431, 25000 Besançon, France;
| | - Vincent Schneider
- Centre des Sciences du Goût et de l’Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, 21000 Dijon, France; (V.S.); (M.P.-S.); (A.B.); (A.J.-P.)
- Neurology and Clinical Neurophysiology Department, CHU F. Mitterrand, 21000 Dijon, France
| | - Manon Perrignon-Sommet
- Centre des Sciences du Goût et de l’Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, 21000 Dijon, France; (V.S.); (M.P.-S.); (A.B.); (A.J.-P.)
| | - Gérard Lizard
- Bio-PeroxIL Laboratory, EA7270, University of Bourgogne, 21000 Dijon, France;
| | - Alexandre Benani
- Centre des Sciences du Goût et de l’Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, 21000 Dijon, France; (V.S.); (M.P.-S.); (A.B.); (A.J.-P.)
| | - Agnès Jacquin-Piques
- Centre des Sciences du Goût et de l’Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, 21000 Dijon, France; (V.S.); (M.P.-S.); (A.B.); (A.J.-P.)
- Neurology and Clinical Neurophysiology Department, CHU F. Mitterrand, 21000 Dijon, France
- Memory Resource and Research Center (CMRR), CHU F. Mitterrand, 21000 Dijon, France
| | - Anne Vejux
- Centre des Sciences du Goût et de l’Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, 21000 Dijon, France; (V.S.); (M.P.-S.); (A.B.); (A.J.-P.)
- Bio-PeroxIL Laboratory, EA7270, University of Bourgogne, 21000 Dijon, France;
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3
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Morera H, Dave P, Kolinko Y, Alahmari S, Anderson A, Denham G, Davis C, Riano J, Goldgof D, Hall LO, Harry GJ, Mouton PR. A novel deep learning-based method for automatic stereology of microglia cells from low magnification images. Neurotoxicol Teratol 2024; 102:107336. [PMID: 38402997 DOI: 10.1016/j.ntt.2024.107336] [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: 11/09/2023] [Revised: 01/31/2024] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Microglial cells mediate diverse homeostatic, inflammatory, and immune processes during normal development and in response to cytotoxic challenges. During these functional activities, microglial cells undergo distinct numerical and morphological changes in different tissue volumes in both rodent and human brains. However, it remains unclear how these cytostructural changes in microglia correlate with region-specific neurochemical functions. To better understand these relationships, neuroscientists need accurate, reproducible, and efficient methods for quantifying microglial cell number and morphologies in histological sections. To address this deficit, we developed a novel deep learning (DL)-based classification, stereology approach that links the appearance of Iba1 immunostained microglial cells at low magnification (20×) with the total number of cells in the same brain region based on unbiased stereology counts as ground truth. Once DL models are trained, total microglial cell numbers in specific regions of interest can be estimated and treatment groups predicted in a high-throughput manner (<1 min) using only low-power images from test cases, without the need for time and labor-intensive stereology counts or morphology ratings in test cases. Results for this DL-based automatic stereology approach on two datasets (total 39 mouse brains) showed >90% accuracy, 100% percent repeatability (Test-Retest) and 60× greater efficiency than manual stereology (<1 min vs. ∼ 60 min) using the same tissue sections. Ongoing and future work includes use of this DL-based approach to establish clear neurodegeneration profiles in age-related human neurological diseases and related animal models.
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Affiliation(s)
- Hunter Morera
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL 33620, USA.
| | - Palak Dave
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Yaroslav Kolinko
- Department of Histology and Embryology & Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Saeed Alahmari
- Department of Computer Science, Najran University, Najran 66462, Saudi Arabia
| | | | | | | | | | - Dmitry Goldgof
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Lawrence O Hall
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL 33620, USA
| | - G Jean Harry
- Mechanistic Toxicology Branch, Division of Translational Toxicology, NIEHS/NIH, Research Triangle Park, NC 27709, USA
| | - Peter R Mouton
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL 33620, USA; SRC Biosciences, Tampa, FL 33606, USA.
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4
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Harry GJ. Developmental Associations between Neurovascularization and Microglia Colonization. Int J Mol Sci 2024; 25:1281. [PMID: 38279280 PMCID: PMC10816009 DOI: 10.3390/ijms25021281] [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: 12/30/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 01/28/2024] Open
Abstract
The temporal and spatial pattern of microglia colonization and vascular infiltration of the nervous system implies critical associated roles in early stages of nervous system development. Adding to existing reviews that cover a broad spectrum of the various roles of microglia during brain development, the current review will focus on the developmental ontogeny and interdependency between the colonization of the nervous system with yolk sac derived macrophages and vascularization. Gaining a better understanding of the timing and the interdependency of these two processes will significantly contribute to the interpretation of data generated regarding alterations in either process during early development. Additionally, such knowledge should provide a framework for understanding the influence of the early gestational environmental and the impact of genetics, disease, disorders, or exposures on the early developing nervous system and the potential for long-term and life-time effects.
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Affiliation(s)
- G Jean Harry
- Mechanistic Toxicology Branch, Division of Translational Toxicology, National Institute Environmental Health Sciences, 111 T.W. Alexander Drive, Research Triangle Park, Durham, NC 27709, USA
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Ishijima T, Nakajima K. Mechanisms of Microglia Proliferation in a Rat Model of Facial Nerve Anatomy. BIOLOGY 2023; 12:1121. [PMID: 37627005 PMCID: PMC10452325 DOI: 10.3390/biology12081121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/27/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Although microglia exist as a minor glial cell type in the normal state of the brain, they increase in number in response to various disorders and insults. However, it remains unclear whether microglia proliferate in the affected area, and the mechanism of the proliferation has long attracted the attention of researchers. We analyzed microglial mitosis using a facial nerve transection model in which the blood-brain barrier is left unimpaired when the nerves are axotomized. Our results showed that the levels of macrophage colony-stimulating factor (M-CSF), cFms (the receptor for M-CSF), cyclin A/D, and proliferating cell nuclear antigen (PCNA) were increased in microglia in the axotomized facial nucleus (axotFN). In vitro experiments revealed that M-CSF induced cFms, cyclin A/D, and PCNA in microglia, suggesting that microglia proliferate in response to M-CSF in vivo. In addition, M-CSF caused the activation of c-Jun N-terminal kinase (JNK) and p38, and the specific inhibitors of JNK and p38 arrested the microglial mitosis. JNK and p38 were shown to play roles in the induction of cyclins/PCNA and cFms, respectively. cFms was suggested to be induced through a signaling cascade of p38-mitogen- and stress-activated kinase-1 (MSK1)-cAMP-responsive element binding protein (CREB) and/or p38-activating transcription factor 2 (ATF2). Microglia proliferating in the axotFN are anticipated to serve as neuroprotective cells by supplying neurotrophic factors and/or scavenging excite toxins and reactive oxygen radicals.
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Affiliation(s)
- Takashi Ishijima
- Graduate School of Science and Engineering, Soka University, Tokyo 192-8577, Japan;
| | - Kazuyuki Nakajima
- Graduate School of Science and Engineering, Soka University, Tokyo 192-8577, Japan;
- Glycan & Life Systems Integration Center, Soka University, Tokyo 192-8577, Japan
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6
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Loras A, Gonzalez-Bonet LG, Gutierrez-Arroyo JL, Martinez-Cadenas C, Marques-Torrejon MA. Neural Stem Cells as Potential Glioblastoma Cells of Origin. Life (Basel) 2023; 13:life13040905. [PMID: 37109434 PMCID: PMC10145968 DOI: 10.3390/life13040905] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Glioblastoma multiforme (GBM) is the most malignant brain tumor in adults and it remains incurable. These tumors are very heterogeneous, resistant to cytotoxic therapies, and they show high rates of invasiveness. Therefore, patients face poor prognosis, and the survival rates remain very low. Previous research states that GBM contains a cell population with stem cell characteristics called glioma stem cells (GSCs). These cells are able to self-renew and regenerate the tumor and, therefore, they are partly responsible for the observed resistance to therapies and tumor recurrence. Recent data indicate that neural stem cells (NSCs) in the subventricular zone (SVZ) are the cells of origin of GBM, that is, the cell type acquiring the initial tumorigenic mutation. The involvement of SVZ-NSCs is also associated with GBM progression and recurrence. Identifying the cellular origin of GBM is important for the development of early detection techniques and the discovery of early disease markers. In this review, we analyze the SVZ-NSC population as a potential GBM cell of origin, and its potential role for GBM therapies.
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Affiliation(s)
- Alba Loras
- Department of Medicine, University of Valencia, 46010 Valencia, Spain
- Department of Medicine, Jaume I University of Castellon, 12071 Castellon de la Plana, Spain
| | - Luis G. Gonzalez-Bonet
- Department of Neurosurgery, Castellon General University Hospital, 12004 Castellon de la Plana, Spain
| | - Julia L. Gutierrez-Arroyo
- Department of Medicine, Jaume I University of Castellon, 12071 Castellon de la Plana, Spain
- Department of Neurosurgery, Castellon General University Hospital, 12004 Castellon de la Plana, Spain
| | | | - Maria Angeles Marques-Torrejon
- Department of Medicine, Jaume I University of Castellon, 12071 Castellon de la Plana, Spain
- Correspondence: ; Tel.: +34-964-387-478
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Decoeur F, Picard K, St-Pierre MK, Greenhalgh AD, Delpech JC, Sere A, Layé S, Tremblay ME, Nadjar A. N-3 PUFA Deficiency Affects the Ultrastructural Organization and Density of White Matter Microglia in the Developing Brain of Male Mice. Front Cell Neurosci 2022; 16:802411. [PMID: 35221920 PMCID: PMC8866569 DOI: 10.3389/fncel.2022.802411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/17/2022] [Indexed: 02/03/2023] Open
Abstract
Over the last century, westernization of dietary habits has led to a dramatic reduction in dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs). In particular, low maternal intake of n-3 PUFAs throughout gestation and lactation causes defects in brain myelination. Microglia are recognized for their critical contribution to neurodevelopmental processes, such as myelination. These cells invade the white matter in the first weeks of the post-natal period, where they participate in oligodendrocyte maturation and myelin production. Therefore, we investigated whether an alteration of white matter microglia accompanies the myelination deficits observed in the brain of n-3 PUFA-deficient animals. Macroscopic imaging analysis shows that maternal n-3 PUFA deficiency decreases the density of white matter microglia around post-natal day 10. Microscopic electron microscopy analyses also revealed alterations of microglial ultrastructure, a decrease in the number of contacts between microglia and myelin sheet, and a decreased amount of myelin debris in their cell body. White matter microglia further displayed increased mitochondrial abundance and network area under perinatal n-3 PUFA deficiency. Overall, our data suggest that maternal n-3 PUFA deficiency alters the structure and function of microglial cells located in the white matter of pups early in life, and this could be the key to understand myelination deficits during neurodevelopment.
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Affiliation(s)
- Fanny Decoeur
- INRAE, Bordeaux INP, NutriNeuro, Université de Bordeaux, Bordeaux, France
| | - Katherine Picard
- Axe Neurosciences, Centre de Recherche du CHU de Québec–Université Laval, Québec, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
| | - Marie-Kim St-Pierre
- Axe Neurosciences, Centre de Recherche du CHU de Québec–Université Laval, Québec, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
| | | | | | - Alexandra Sere
- INRAE, Bordeaux INP, NutriNeuro, Université de Bordeaux, Bordeaux, France
| | - Sophie Layé
- INRAE, Bordeaux INP, NutriNeuro, Université de Bordeaux, Bordeaux, France
| | - Marie-Eve Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec–Université Laval, Québec, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Agnès Nadjar
- INRAE, Bordeaux INP, NutriNeuro, Université de Bordeaux, Bordeaux, France
- Neurocentre Magendie, U1215, INSERM-Université de Bordeaux, Bordeaux, France
- Institut Universitaire de France (IUF), Paris, France
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Jin N, Sha W, Gao L. Shaping the Microglia in Retinal Degenerative Diseases Using Stem Cell Therapy: Practice and Prospects. Front Cell Dev Biol 2021; 9:741368. [PMID: 34966736 PMCID: PMC8710684 DOI: 10.3389/fcell.2021.741368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/29/2021] [Indexed: 12/11/2022] Open
Abstract
Retinal degenerative disease (RDD) refers to a group of diseases with retinal degeneration that cause vision loss and affect people's daily lives. Various therapies have been proposed, among which stem cell therapy (SCT) holds great promise for the treatment of RDDs. Microglia are immune cells in the retina that have two activation phenotypes, namely, pro-inflammatory M1 and anti-inflammatory M2 phenotypes. These cells play an important role in the pathological progression of RDDs, especially in terms of retinal inflammation. Recent studies have extensively investigated the therapeutic potential of stem cell therapy in treating RDDs, including the immunomodulatory effects targeting microglia. In this review, we substantially summarized the characteristics of RDDs and microglia, discussed the microglial changes and phenotypic transformation of M1 microglia to M2 microglia after SCT, and proposed future directions for SCT in treating RDDs.
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Affiliation(s)
- Ni Jin
- Senior Department of Ophthalmology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China.,Department of Endocrinology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Weiwei Sha
- Department of Endocrinology, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese People's Liberation Army General Hospital, Beijing, China
| | - Lixiong Gao
- Senior Department of Ophthalmology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, China
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Santos EN, Fields RD. Regulation of myelination by microglia. SCIENCE ADVANCES 2021; 7:eabk1131. [PMID: 34890221 PMCID: PMC8664250 DOI: 10.1126/sciadv.abk1131] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/25/2021] [Indexed: 05/03/2023]
Abstract
Interactions between microglia, the resident macrophages of the central nervous system (CNS), and myelin, the glial sheath on nerve fibers essential for rapid neural impulse transmission, are commonly studied in the context of neurotrauma and disease. However, interactions between microglia and myelin under normal physiological conditions have been largely overlooked. This review summarizes recent research indicating that the unique properties of microglia evident in disease states also enable microglia to regulate myelination during development and throughout life. This includes phagocytosis of cells and myelin membrane as well as the release of trophic factors, cytokines, and chemokines. The ability of microglia to sense neuronal activity and molecular features of the microenvironment enables them to optimize myelination by influencing early oligodendrogenesis, myelin formation, and removal of aberrantly targeted myelin. Understanding how microglia participate in myelination under normal conditions provides a new perspective that will increase understanding of developmental abnormalities.
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Affiliation(s)
- Erin N. Santos
- Section on Nervous System Development and Plasticity, The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
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10
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Irfan M, Evonuk KS, DeSilva TM. Microglia phagocytose oligodendrocyte progenitor cells and synapses during early postnatal development: implications for white versus gray matter maturation. FEBS J 2021; 289:2110-2127. [PMID: 34496137 DOI: 10.1111/febs.16190] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/21/2021] [Accepted: 09/07/2021] [Indexed: 12/22/2022]
Abstract
Emerging roles for microglia in modifying normal brain development continue to provide new perspectives on the functions of this resident immune cell in the brain. While the molecular underpinnings driving microglia's position in regulating developmental programs remain largely an unchartered territory, innate immune signaling lies at the forefront. At least three innate immune receptors expressed on microglia-fractalkine, complement, and triggering receptor expressed on microglia (TREM2)-modulate developmental synaptic pruning to refine brain circuitry. Our laboratory recently published that microglia with a unique amoeboid morphology invade the corpus callosum and engulf oligodendrocyte progenitor cells (OPCs) during early postnatal development before myelination in a fractalkine receptor (CX3CR1)-dependent manner to modulate ensheathment of axons. Amoeboid microglia are observed in the corpus callosum but not cerebral cortex, and lose their amoeboid shape at the commencement of myelination assuming a resting phenotype. Furthermore, OPCs contacted or engulfed by microglia do not express markers of cell death suggesting a novel homeostatic mechanism facilitating an appropriate OPC:axon ratio for proper myelin ensheathment. The unique morphology of microglia and the restricted window for phagocytic engulfment of OPCs suggest a critical period for OPC engulfment important for action potential propagation during development when activity-dependent mechanisms regulate synaptic pruning. In this review, we summarize the role of activity-dependent mechanisms in sculpting brain circuitry, how myelin ensheathment influences action potential propagation, the spatial and temporal relationship of microglia-dependent elimination of OPCs and synapses, and implications for the synergistic role of microglial phagocytosis in shaping the architecture for neuronal function.
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Affiliation(s)
- Muhammad Irfan
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Kirsten S Evonuk
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Tara M DeSilva
- Department of Neurosciences, Cleveland Clinic Foundation, Cleveland, OH, USA
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11
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Nemes-Baran AD, White DR, DeSilva TM. Fractalkine-Dependent Microglial Pruning of Viable Oligodendrocyte Progenitor Cells Regulates Myelination. Cell Rep 2021; 32:108047. [PMID: 32814050 PMCID: PMC7478853 DOI: 10.1016/j.celrep.2020.108047] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/22/2020] [Accepted: 07/28/2020] [Indexed: 12/14/2022] Open
Abstract
Oligodendrogenesis occurs during early postnatal development, coincident with neurogenesis and synaptogenesis, raising the possibility that microglia-dependent pruning mechanisms that modulate neurons regulate myelin sheath formation. Here we show a population of ameboid microglia migrating from the ventricular zone into the corpus callosum during early postnatal development, termed “the fountain of microglia,” phagocytosing viable oligodendrocyte progenitor cells (OPCs) before onset of myelination. Fractalkine receptor-deficient mice exhibit a reduction in microglial engulfment of viable OPCs, increased numbers of oligodendrocytes, and reduced myelin thickness but no change in axon number. These data provide evidence that microglia phagocytose OPCs as a homeostatic mechanism for proper myelination. A hallmark of hypomyelinating developmental disorders such as periventricular leukomalacia and of adult demyelinating diseases such as multiple sclerosis is increased numbers of oligodendrocytes but failure to myelinate, suggesting that microglial pruning of OPCs may be impaired in pathological states and hinder myelination. Nemes-Baran et al. show that ameboid microglia engulf living oligodendrocyte progenitor cells (OPCs) during brain development. Fractalkine receptor-deficient microglia exhibit a reduction in engulfment of OPCs, resulting in a surplus of oligodendrocytes and impaired myelination. These data provide evidence that microglia phagocytose OPCs as a homeostatic mechanism required for normal myelination.
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Affiliation(s)
- Ashley D Nemes-Baran
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Donovan R White
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Tara M DeSilva
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA.
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12
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Fujita Y, Yamashita T. Mechanisms and significance of microglia-axon interactions in physiological and pathophysiological conditions. Cell Mol Life Sci 2021; 78:3907-3919. [PMID: 33507328 PMCID: PMC11072252 DOI: 10.1007/s00018-021-03758-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/28/2020] [Accepted: 01/06/2021] [Indexed: 12/15/2022]
Abstract
Microglia are the resident immune cells of the central nervous system, and are important for cellular processes. In addition to their classical roles in pathophysiological conditions, these immune cells also dynamically interact with neurons and influence their structure and function in physiological conditions. Microglia have been shown to contact neurons at various points, including the dendrites, cell bodies, synapses, and axons, and support various developmental functions, such as neuronal survival, axon elongation, and maturation of the synaptic circuit. This review summarizes the current knowledge regarding the roles of microglia in brain development, with particular emphasis on microglia-axon interactions. We will review recent findings regarding the functions and signaling pathways involved in the reciprocal interactions between microglia and neurons. Moreover, as these interactions are altered in disease and injury conditions, we also discuss the effect and alteration of microglia-axon interactions in disease progression and the potential role of microglia in developmental brain disorders.
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Affiliation(s)
- Yuki Fujita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- WPI Immunology Frontier Research Center, Osaka University, 3-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- WPI Immunology Frontier Research Center, Osaka University, 3-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Graduate School of Frontier Bioscience, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
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13
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Yu L, Su X, Li S, Zhao F, Mu D, Qu Y. Microglia and Their Promising Role in Ischemic Brain Injuries: An Update. Front Cell Neurosci 2020; 14:211. [PMID: 32754016 PMCID: PMC7365911 DOI: 10.3389/fncel.2020.00211] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/16/2020] [Indexed: 12/14/2022] Open
Abstract
Ischemic brain injuries are common diseases with high morbidity, disability, and mortality rates, which have significant impacts on human health and life. Microglia are resident cells of the central nervous system (CNS). The inflammatory responses mediated by microglia play an important role in the occurrence and development of ischemic brain injuries. This article summarizes the activation, polarization, depletion, and repopulation of microglia after ischemic brain injuries, proposing new treatment strategies for such injuries through the modulation of microglial function.
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Affiliation(s)
- Luting Yu
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Xiaojuan Su
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Shiping Li
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Fengyan Zhao
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Dezhi Mu
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
| | - Yi Qu
- Department of Paediatrics, West China Second University Hospital, Sichuan University, Chengdu, China.,Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, China
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14
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Traiffort E, Kassoussi A, Zahaf A, Laouarem Y. Astrocytes and Microglia as Major Players of Myelin Production in Normal and Pathological Conditions. Front Cell Neurosci 2020; 14:79. [PMID: 32317939 PMCID: PMC7155218 DOI: 10.3389/fncel.2020.00079] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/19/2020] [Indexed: 12/13/2022] Open
Abstract
Myelination is an essential process that consists of the ensheathment of axons by myelin. In the central nervous system (CNS), myelin is synthesized by oligodendrocytes. The proliferation, migration, and differentiation of oligodendrocyte precursor cells constitute a prerequisite before mature oligodendrocytes extend their processes around the axons and progressively generate a multilamellar lipidic sheath. Although myelination is predominately driven by oligodendrocytes, the other glial cells including astrocytes and microglia, also contribute to this process. The present review is an update of the most recent emerging mechanisms involving astrocyte and microglia in myelin production. The contribution of these cells will be first described during developmental myelination that occurs in the early postnatal period and is critical for the proper development of cognition and behavior. Then, we will report the novel findings regarding the beneficial or deleterious effects of astroglia and microglia, which respectively promote or impair the endogenous capacity of oligodendrocyte progenitor cells (OPCs) to induce spontaneous remyelination after myelin loss. Acute delineation of astrocyte and microglia activities and cross-talk should uncover the way towards novel therapeutic perspectives aimed at recovering proper myelination during development or at breaking down the barriers impeding the regeneration of the damaged myelin that occurs in CNS demyelinating diseases.
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Affiliation(s)
| | | | - Amina Zahaf
- U1195 Inserm, University Paris-Saclay, Kremlin-Bicêtre, France
| | - Yousra Laouarem
- U1195 Inserm, University Paris-Saclay, Kremlin-Bicêtre, France
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15
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Benmamar-Badel A, Owens T, Wlodarczyk A. Protective Microglial Subset in Development, Aging, and Disease: Lessons From Transcriptomic Studies. Front Immunol 2020; 11:430. [PMID: 32318054 PMCID: PMC7147523 DOI: 10.3389/fimmu.2020.00430] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/25/2020] [Indexed: 12/25/2022] Open
Abstract
Microglial heterogeneity has been the topic of much discussion in the scientific community. Elucidation of their plasticity and adaptability to disease states triggered early efforts to characterize microglial subsets. Over time, their phenotypes, and later on their homeostatic signature, were revealed, through the use of increasingly advanced transcriptomic techniques. Recently, an increasing number of these "microglial signatures" have been reported in various homeostatic and disease contexts. Remarkably, many of these states show similar overlapping microglial gene expression patterns, both in homeostasis and in disease or injury. In this review, we integrate information from these studies, and we propose a unique subset, for which we introduce a core signature, based on our own research and reports from the literature. We describe that this subset is found in development and in normal aging as well as in diverse diseases. We discuss the functions of this subset as well as how it is induced.
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Affiliation(s)
- Anouk Benmamar-Badel
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
- BRIDGE, Brain Research - Inter-Disciplinary Guided Excellence, Odense, Denmark
- Department of Neurology, Slagelse Hospital, Institute of Regional Health Research, Slagelse, Denmark
| | - Trevor Owens
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
- BRIDGE, Brain Research - Inter-Disciplinary Guided Excellence, Odense, Denmark
| | - Agnieszka Wlodarczyk
- Department of Neurobiology Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark
- BRIDGE, Brain Research - Inter-Disciplinary Guided Excellence, Odense, Denmark
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16
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Alekseeva OS, Kirik OV, Gilerovich EG, Korzhevskii DE. Microglia of the Brain: Origin, Structure, Functions. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s002209301904001x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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17
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Rathnasamy G, Foulds WS, Ling EA, Kaur C. Retinal microglia - A key player in healthy and diseased retina. Prog Neurobiol 2018; 173:18-40. [PMID: 29864456 DOI: 10.1016/j.pneurobio.2018.05.006] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/09/2018] [Accepted: 05/29/2018] [Indexed: 01/04/2023]
Abstract
Microglia, the resident immune cells of the brain and retina, are constantly engaged in the surveillance of their surrounding neural tissue. During embryonic development they infiltrate the retinal tissues and participate in the phagocytosis of redundant neurons. The contribution of microglia in maintaining the purposeful and functional histo-architecture of the adult retina is indispensable. Within the retinal microenvironment, robust microglial activation is elicited by subtle changes caused by extrinsic and intrinsic factors. When there is a disturbance in the cell-cell communication between microglia and other retinal cells, for example in retinal injury, the activated microglia can manifest actions that can be detrimental. This is evidenced by activated microglia secreting inflammatory mediators that can further aggravate the retinal injury. Microglial activation as a harbinger of a variety of retinal diseases is well documented by many studies. In addition, a change in the microglial phenotype which may be associated with aging, may predispose the retina to age-related diseases. In light of the above, the focus of this review is to highlight the role played by microglia in the healthy and diseased retina, based on findings of our own work and from that of others.
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Affiliation(s)
- Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore; Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, United States
| | - Wallace S Foulds
- Singapore Eye Research Institute Level 6, The Academia, Discovery Tower, 20 College Road, 169856, Singapore; University of Glasgow, Glasgow, Scotland, G12 8QQ, United Kingdom
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore
| | - Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, 117594, Singapore.
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Kaur C, Rathnasamy G, Ling EA. Biology of Microglia in the Developing Brain. J Neuropathol Exp Neurol 2017; 76:736-753. [PMID: 28859332 DOI: 10.1093/jnen/nlx056] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Microglia exist in different morphological forms in the developing brain. They show a small cell body with scanty cytoplasm with many branching processes in the grey matter of the developing brain. However, in the white matter such as the corpus callosum where the unmyelinated axons are loosely organized, they appear in an amoeboid form having a round cell body endowed with copious cytoplasm rich in organelles. The amoeboid cells eventually transform into ramified microglia in the second postnatal week when the tissue becomes more compact with the onset of myelination. Microglia serve as immunocompetent macrophages that act as neuropathology sensors to detect and respond swiftly to subtle changes in the brain tissues in pathological conditions. Microglial functions are broadly considered as protective in the normal brain development as they phagocytose dead cells and sculpt neuronal connections by pruning excess axons and synapses. They also secrete a number of trophic factors such as insulin-like growth factor-1 and transforming growth factor-β among many others that are involved in neuronal and oligodendrocyte survival. On the other hand, microglial cells when activated produce a plethora of molecules such as proinflammatory cytokines, chemokines, reactive oxygen species, and nitric oxide that are implicated in the pathogenesis of many pathological conditions such as epilepsy, cerebral palsy, autism, and perinatal hypoxic-ischemic brain injury. Although many studies have investigated the origin and functions of the microglia in the developing brain, in-depth in vivo studies along with analysis of their transcriptome and epigenetic changes need to be undertaken to elucidate their full potential be it protective or neurotoxic. This would lead to a better understanding of their roles in the healthy and diseased developing brain and advancement of therapeutic strategies to target microglia-mediated neurotoxicity.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Gurugirijha Rathnasamy
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; and Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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19
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Microglia contribute to normal myelinogenesis and to oligodendrocyte progenitor maintenance during adulthood. Acta Neuropathol 2017; 134:441-458. [PMID: 28685323 DOI: 10.1007/s00401-017-1747-1] [Citation(s) in RCA: 336] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/14/2017] [Accepted: 07/01/2017] [Indexed: 12/11/2022]
Abstract
Whereas microglia involvement in virtually all brain diseases is well accepted their role in the control of homeostasis in the central nervous system (CNS) is mainly thought to be the maintenance of neuronal function through the formation, refinement, and monitoring of synapses in both the developing and adult brain. Although the prenatal origin as well as the neuron-centered function of cortical microglia has recently been elucidated, much less is known about a distinct amoeboid microglia population formerly described as the "fountain of microglia" that appears only postnatally in myelinated regions such as corpus callosum and cerebellum. Using large-scale transcriptional profiling, fate mapping, and genetic targeting approaches, we identified a unique molecular signature of this microglia subset that arose from a CNS endogenous microglia pool independent from circulating myeloid cells. Microglia depletion experiments revealed an essential role of postnatal microglia for the proper development and homeostasis of oligodendrocytes and their progenitors. Our data provide new cellular and molecular insights into the myelin-supporting function of microglia in the normal CNS.
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20
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Delcambre GH, Liu J, Streit WJ, Shaw GPJ, Vallario K, Herrington J, Wenzlow N, Barr KL, Long MT. Phenotypic characterisation of cell populations in the brains of horses experimentally infected with West Nile virus. Equine Vet J 2017; 49:815-820. [PMID: 28470955 DOI: 10.1111/evj.12697] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 04/21/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND West Nile virus (WNV), a mosquito borne member of the Flaviviridae, is one of the most commonly diagnosed agents of viral encephalitis in horses and people worldwide. OBJECTIVES A cassette of markers for formalin-fixed paraffin-embedded tissue and an archive of tissues from experimental infections in the horse were used to investigate the equine neuroimmune response to WNV meningoencephalomyelitis to phenotype the early response to WNV infection in the horse. STUDY DESIGN Quantitative analysis using archived tissue from experimentally infected horses. METHODS The thalamus and hindbrain from 2 groups of 6 horses were compared and consisted of a culture positive tissues from WNV experimentally horses, in the other, normal horses. Formalin-fixed paraffin-embedded tissue from the thalamus and hindbrain were immunolabeled for microglia, astrocytes, B cells, macrophages/neutrophils, CD3+ T cells. Fresh frozen tissues were immunolabeled for CD4+ and CD8+ T lymphocyte cell markers. Cell counts were obtained using a computer software program. Differences, after meeting assumptions of abnormality, were computed using a general linear model with a Tukey test (P<0.05) for pairwise comparisons. RESULTS In WNV-challenged horses, Iba-1+ microglia, CD3+ T lymphocyte and MAC387+ macrophage staining were significantly increased. The T cell response for the WNV-challenged horses was mixed, composed of CD4+ and CD8+ T lymphocytes. A limited astrocyte response was also observed in WNV-challenged horses, and MAC387+ and B cells were the least abundant cell populations. MAIN LIMITATIONS The results of this study were limited by a single collection time post-infection. Furthermore, a comprehensive analysis of cellular phenotypes is needed for naturally infected horses. Unfortunately, in clinical horses, there is high variability of sampling in terms of days post-infection and tissue handling. CONCLUSIONS The data show that WNV-challenged horses recruit a mixed T cell population at the onset of neurologic disease.
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Affiliation(s)
- G H Delcambre
- Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - J Liu
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - W J Streit
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - G P J Shaw
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - K Vallario
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - J Herrington
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - N Wenzlow
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - K L Barr
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - M T Long
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
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21
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Mosser CA, Baptista S, Arnoux I, Audinat E. Microglia in CNS development: Shaping the brain for the future. Prog Neurobiol 2017; 149-150:1-20. [DOI: 10.1016/j.pneurobio.2017.01.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/24/2017] [Accepted: 01/24/2017] [Indexed: 12/22/2022]
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22
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Kaur C, Ling EA. Transitory cystic cavities in the developing mammalian brain - normal or anomalous? J Anat 2016; 230:197-202. [PMID: 27761896 DOI: 10.1111/joa.12556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2016] [Indexed: 11/28/2022] Open
Abstract
Transitory cavities associated with the ventricular system represent probably one of the most unique features in the developing mammalian brain. In rodents, the cavities exist transiently in the developing brain and do not appear to be associated with any pathological events. Among the various cavities, the pyramidal-shaped cavum septum pellucidum (CSP) located beneath the corpus callosum and between the lateral ventricles is most well defined. In addition to the CSP are the bilateral subependymal cysts that are consistently associated with the third and fourth ventricles as well as the aqueduct. The cavities/cysts contain a large number of amoeboid microglia expressing surface receptors and hydrolytic enzymes common to tissue macrophages. The significance of these cavities in the developing brain remains a conjecture. Firstly, the cavity walls are free of an apparent epithelial lining; hence, it is speculated that the cavities that appear to communicate with the widened neighboring interstitial tissue spaces may have resulted from physical traction due to the rapid growth of the perinatal brain. Secondly, the cavities contain prominent clusters of amoeboid microglia that may be involved in clearing the debris of degenerating axons and cells resulting from the early brain tissue remodeling. With the increase in brain tissue compactness following the beginning of myelination in the second postnatal week, all cavities are obliterated; concomitantly, the number of amoeboid microglia in them diminishes and all this might signal further maturation of the brain.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Eng-Ang Ling
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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23
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Kawahara K, Hirata H, Ohbuchi K, Nishi K, Maeda A, Kuniyasu A, Yamada D, Maeda T, Tsuji A, Sawada M, Nakayama H. The novel monoclonal antibody 9F5 reveals expression of a fragment of GPNMB/osteoactivin processed by furin-like protease(s) in a subpopulation of microglia in neonatal rat brain. Glia 2016; 64:1938-61. [PMID: 27464357 PMCID: PMC5129557 DOI: 10.1002/glia.23034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 07/02/2016] [Accepted: 07/07/2016] [Indexed: 12/19/2022]
Abstract
To differentiate subtypes of microglia (MG), we developed a novel monoclonal antibody, 9F5, against one subtype (type 1) of rat primary MG. The 9F5 showed high selectivity for this cell type in Western blot and immunocytochemical analyses and no cross-reaction with rat peritoneal macrophages (Mφ). We identified the antigen molecule for 9F5: the 50- to 70-kDa fragments of rat glycoprotein nonmetastatic melanoma protein B (GPNMB)/osteoactivin, which started at Lys(170) . In addition, 9F5 immunoreactivity with GPNMB depended on the activity of furin-like protease(s). More important, rat type 1 MG expressed the GPNMB fragments, but type 2 MG and Mφ did not, although all these cells expressed mRNA and the full-length protein for GPNMB. These results suggest that 9F5 reactivity with MG depends greatly on cleavage of GPNMB and that type 1 MG, in contrast to type 2 MG and Mφ, may have furin-like protease(s) for GPNMB cleavage. In neonatal rat brain, amoeboid 9F5+ MG were observed in specific brain areas including forebrain subventricular zone, corpus callosum, and retina. Double-immunοstaining with 9F5 antibody and anti-Iba1 antibody, which reacts with MG throughout the CNS, revealed that 9F5+ MG were a portion of Iba1+ MG, suggesting that MG subtype(s) exist in vivo. We propose that 9F5 is a useful tool to discriminate between rat type 1 MG and other subtypes of MG/Mφ and to reveal the role of the GPNMB fragments during developing brain. GLIA 2016;64:1938-1961.
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Affiliation(s)
- Kohichi Kawahara
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan. .,Department of Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Niigata, 956-8603, Japan.
| | - Hiroshi Hirata
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan
| | - Kengo Ohbuchi
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan
| | - Kentaro Nishi
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan
| | - Akira Maeda
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan
| | - Akihiko Kuniyasu
- Department of Molecular Cell Pharmacology, Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Kumamoto, 860-0082, Japan
| | - Daisuke Yamada
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Niigata, 956-8603, Japan
| | - Takehiko Maeda
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Niigata, 956-8603, Japan
| | - Akihiko Tsuji
- Department of Biological Science and Technology, the University of Tokushima Graduate School, 2-1 Minamijosanjima, Tokushima, 770-8506, Japan
| | - Makoto Sawada
- Department of Brain Functions, Research Institute of Environmental Medicine, Nagoya University, Nagoya, 464-8601, Japan
| | - Hitoshi Nakayama
- Department of Molecular Cell Function, Faculty of Life Sciences, Kumamoto University, 5-1 Ohe-Honmachi, Kumamoto, 862-0973, Japan.
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Xavier AL, Menezes JRL, Goldman SA, Nedergaard M. Fine-tuning the central nervous system: microglial modelling of cells and synapses. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130593. [PMID: 25225087 DOI: 10.1098/rstb.2013.0593] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Microglia constitute as much as 10-15% of all cells in the mammalian central nervous system (CNS) and are the only glial cells that do not arise from the neuroectoderm. As the principal CNS immune cells, microglial cells represent the first line of defence in response to exogenous threats. Past studies have largely been dedicated to defining the complex immune functions of microglial cells. However, our understanding of the roles of microglia has expanded radically over the past years. It is now clear that microglia are critically involved in shaping neural circuits in both the developing and adult CNS, and in modulating synaptic transmission in the adult brain. Intriguingly, microglial cells appear to use the same sets of tools, including cytokine and chemokine release as well as phagocytosis, whether modulating neural function or mediating the brain's innate immune responses. This review will discuss recent developments that have broadened our views of neuro-glial signalling to include the contribution of microglial cells.
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Affiliation(s)
- Anna L Xavier
- Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14642, USA
| | - João R L Menezes
- Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Steven A Goldman
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14642, USA
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Böhm MRR, Melkonyan H, Thanos S. Life-time expression of the proteins peroxiredoxin, beta-synuclein, PARK7/DJ-1, and stathmin in the primary visual and primary somatosensory cortices in rats. Front Neuroanat 2015; 9:16. [PMID: 25788877 PMCID: PMC4349188 DOI: 10.3389/fnana.2015.00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/04/2015] [Indexed: 11/16/2022] Open
Abstract
Four distinct proteins are regulated in the aging neuroretina and may be regulated in the cerebral cortex, too: peroxiredoxin, beta-synuclein, PARK[Parkinson disease(autosomal recessive, early onset)]7/DJ-1, and Stathmin. Thus, we performed a comparative analysis of these proteins in the the primary somatosensory cortex (S1) and primary visual cortex (V1) in rats, in order to detect putative common development-, maturation- and age-related changes. The expressions of peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin were compared in the newborn, juvenile, adult, and aged S1 and V1. Western blot (WB), quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and immunohistochemistry (IHC) analyses were employed to determine whether the changes identified by proteomics were verifiable at the cellular and molecular levels. All of the proteins were detected in both of the investigated cortical areas. Changes in the expressions of the four proteins were found throughout the life-time of the rats. Peroxiredoxin expression remained unchanged over life-time. Beta-Synuclein expression was massively increased up to the adult stage of life in both the S1 and V1. PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1 exhibited a massive up-regulation in both the S1 and V1 at all ages. Stathmin expression was massively down regulated after the neonatal period in both the S1 and V1. The detected protein alterations were analogous to their retinal profiles. This study is the first to provide evidence that peroxiredoxin, beta-synuclein, PARK[Parkinson disease (autosomal recessive, early onset)]7/DJ-1, and Stathmin are associated with postnatal maturation and aging in both the S1 and V1 of rats. These changes may indicate their involvement in key functional pathways and may account for the onset or progression of age-related pathologies.
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Affiliation(s)
- Michael R R Böhm
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany ; Department of Ophthalmology, St. Franziskus Hospital Münster Münster, Germany
| | - Harutyun Melkonyan
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany
| | - Solon Thanos
- Institute of Experimental Ophthalmology and DFG-Center of Excellence Cells in Motion (CiM), area C.4, School of Medicine, Westfalian-Wilhelms-University of Münster Münster, Germany
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26
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Xavier AL, Lima FRS, Nedergaard M, Menezes JRL. Ontogeny of CX3CR1-EGFP expressing cells unveil microglia as an integral component of the postnatal subventricular zone. Front Cell Neurosci 2015; 9:37. [PMID: 25741237 PMCID: PMC4330885 DOI: 10.3389/fncel.2015.00037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/21/2015] [Indexed: 01/29/2023] Open
Abstract
The full spectrum of cellular interactions within CNS neurogenic niches is still poorly understood. Only recently has the monocyte counterpart of the nervous system, the microglial cells, been described as an integral cellular component of neurogenic niches. The present study sought to characterize the microglia population in the early postnatal subventricular zone (SVZ), the major site of postnatal neurogenesis, as well as in its anterior extension, the rostral migratory stream (RMS), a pathway for neuroblasts during their transit toward the olfactory bulb (OB) layers. Here we show that microglia within the SVZ/RMS pathway are not revealed by phenotypic markers that characterize microglia in other regions. Analysis of the transgenic mice strain that has one locus of the constitutively expressed fractalkine CX3CR1 receptor replaced by the gene encoding the enhanced green fluorescent protein (EGFP) circumvented the antigenic plasticity of the microglia, thus allowing us to depict microglia within the SVZ/RMS pathway during early development. Notably, microglia within the early SVZ/RMS are not proliferative and display a protracted development, retaining a more immature morphology than their counterparts outside germinal layers. Furthermore, microglia contact and phagocyte radial glia cells (RG) processes, thereby playing a role on the astroglial transformation that putative stem cells within the SVZ niche undergo during the first postnatal days.
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Affiliation(s)
- Anna L Xavier
- Programa em Ciências Morfológicas, Programa de Diferenciação Celular, Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Center for Translational Neuromedicine, University of Rochester Medical School Rochester, NY, USA
| | - Flavia R S Lima
- Laboratório de Morfogênese Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical School Rochester, NY, USA
| | - João R L Menezes
- Programa em Ciências Morfológicas, Programa de Diferenciação Celular, Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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Old EA, Clark AK, Malcangio M. The role of glia in the spinal cord in neuropathic and inflammatory pain. Handb Exp Pharmacol 2015; 227:145-170. [PMID: 25846618 DOI: 10.1007/978-3-662-46450-2_8] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chronic pain, both inflammatory and neuropathic, is a debilitating condition in which the pain experience persists after the painful stimulus has resolved. The efficacy of current treatment strategies using opioids, NSAIDS and anticonvulsants is limited by the extensive side effects observed in patients, underlining the necessity for novel therapeutic targets. Preclinical models of chronic pain have recently provided evidence for a critical role played by glial cells in the mechanisms underlying the chronicity of pain, both at the site of damage in the periphery and in the dorsal horn of the spinal cord. Here microglia and astrocytes respond to the increased input from the periphery and change morphology, increase in number and release pro-nociceptive mediators such as ATP, cytokines and chemokines. These gliotransmitters can sensitise neurons by activation of their cognate receptors thereby contributing to central sensitization which is fundamental for the generation of allodynia, hyperalgesia and spontaneous pain.
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Affiliation(s)
- Elizabeth Amy Old
- Wolfson Centre for Age Related Diseases, King's College London, London, UK
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Nikodemova M, Kimyon RS, De I, Small AL, Collier LS, Watters JJ. Microglial numbers attain adult levels after undergoing a rapid decrease in cell number in the third postnatal week. J Neuroimmunol 2014; 278:280-8. [PMID: 25468773 DOI: 10.1016/j.jneuroim.2014.11.018] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 12/23/2022]
Abstract
During postnatal development, microglia, CNS resident innate immune cells, are essential for synaptic pruning, neuronal apoptosis and remodeling. During this period microglia undergo morphological and phenotypic transformations; however, little is known about how microglial number and density is regulated during postnatal CNS development. We found that after an initial increase during the first 14 postnatal days, microglial numbers in mouse brain began declining in the third postnatal week and were reduced by 50% by 6weeks of age; these "adult" levels were maintained until at least 9months of age. Microglial CD11b levels increased, whereas CD45 and ER-MP58 declined between P10 and adulthood, consistent with a maturing microglial phenotype. Our data indicate that both increased microglial apoptosis and a decreased proliferative capacity contribute to the developmental reduction in microglial numbers. We found no correlation between developmental reductions in microglial numbers and brain mRNA levels of Cd200, Cx3Cl1, M-Csf or Il-34. We tested the ability of M-Csf-overexpression, a key growth factor promoting microglial proliferation and survival, to prevent microglial loss in the third postnatal week. Mice overexpressing M-Csf in astrocytes had higher numbers of microglia at all ages tested. However, the developmental decline in microglial numbers still occurred, suggesting that chronically elevated M-CSF is unable to overcome the developmental decrease in microglial numbers. Whereas the identity of the factor(s) regulating microglial number and density during development remains to be determined, it is likely that microglia respond to a "maturation" signal since the reduction in microglial numbers coincides with CNS maturation.
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Affiliation(s)
- Maria Nikodemova
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Rebecca S Kimyon
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Ishani De
- School of Pharmacy and Molecular and Cellular Pharmacology Graduate Program, University of Wisconsin-Madison, United States
| | - Alissa L Small
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States
| | - Lara S Collier
- School of Pharmacy and Molecular and Cellular Pharmacology Graduate Program, University of Wisconsin-Madison, United States
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin-Madison, United States.
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Developmental neurotoxicity of 3,3',4,4'-tetrachloroazobenzene with thyroxine deficit: Sensitivity of glia and dentate granule neurons in the absence of behavioral changes. TOXICS 2014; 2:496-532. [PMID: 26029700 PMCID: PMC4445902 DOI: 10.3390/toxics2030496] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thyroid hormones (TH) regulate biological processes implicated in neurodevelopmental disorders and can be altered with environmental exposures. Developmental exposure to the dioxin-like compound, 3,3',4,4'-tetrachloroazobenzene (TCAB), induced a dose response deficit in serum T4 levels with no change in 3,5,3'- triiodothyronine or thyroid stimulating hormone. Female Sprague-Dawley rats were orally gavaged (corn oil, 0.1, 1.0, or 10 mg TCAB/kg/day) two weeks prior to cohabitation until post-partum day 3 and male offspring from post-natal day (PND)4-21. At PND21, the high dose showed a deficit in body weight gain. Conventional neuropathology detected no neuronal death, myelin disruption, or gliosis. Astrocytes displayed thinner and less complex processes at 1.0 and 10 mg/kg/day. At 10 mg/kg/day, microglia showed less complex processes, unbiased stereology detected fewer hippocampal CA1 pyramidal neurons and dentate granule neurons (GC) and Golgi staining of the cerebellum showed diminished Purkinje cell dendritic arbor. At PND150, normal maturation of GC number and Purkinje cell branching area was not observed in the 1.0 mg/kg/day dose group with a diminished number and branching suggestive of effects initiated during developmental exposure. No effects were observed on post-weaning behavioral assessments in control, 0.1 and 1.0mg/kg/day dose groups. The demonstrated sensitivity of hippocampal neurons and glial cells to TCAB and T4 deficit raises support for considering additional anatomical features of brain development in future DNT evaluations.
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Abstract
Microglia are critical nervous system-specific cells influencing brain development, maintenance of the neural environment, response to injury, and repair. They contribute to neuronal proliferation and differentiation, pruning of dying neurons, synaptic remodeling and clearance of debris and aberrant proteins. Colonization of the brain occurs during gestation with an expansion following birth with localization stimulated by programmed neuronal death, synaptic pruning, and axonal degeneration. Changes in microglia phenotype relate to cellular processes including specific neurotransmitter, pattern recognition, or immune-related receptor activation. Upon activation, microglia cells have the capacity to release a number of substances, e.g., cytokines, chemokines, nitric oxide, and reactive oxygen species, which could be detrimental or beneficial to the surrounding cells. With aging, microglia shift their morphology and may display diminished capacity for normal functions related to migration, clearance, and the ability to shift from a pro-inflammatory to an anti-inflammatory state to regulate injury and repair. This shift in microglia potentially contributes to increased susceptibility and neurodegeneration as a function of age. In the current review, information is provided on the colonization of the brain by microglia, the expression of various pattern recognition receptors to regulate migration and phagocytosis, and the shift in related functions that occur in normal aging.
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Affiliation(s)
- G Jean Harry
- National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, MD C1-04, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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Abstract
We immunocytochemically identified microglia in fronto-insular (FI) and visual cortex (VC) in autopsy brains of well-phenotyped subjects with autism and matched controls, and stereologically quantified the microglial densities. Densities were determined blind to phenotype using an optical fractionator probe. In FI, individuals with autism had significantly more microglia compared to controls (p = 0.02). One such subject had a microglial density in FI within the control range and was also an outlier behaviorally with respect to other subjects with autism. In VC, microglial densities were also significantly greater in individuals with autism versus controls (p = 0.0002). Since we observed increased densities of microglia in two functionally and anatomically disparate cortical areas, we suggest that these immune cells are probably denser throughout cerebral cortex in brains of people with autism.
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Ginhoux F, Lim S, Hoeffel G, Low D, Huber T. Origin and differentiation of microglia. Front Cell Neurosci 2013; 7:45. [PMID: 23616747 PMCID: PMC3627983 DOI: 10.3389/fncel.2013.00045] [Citation(s) in RCA: 554] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/30/2013] [Indexed: 12/30/2022] Open
Abstract
Microglia are the resident macrophage population of the central nervous system (CNS). Adequate microglial function is crucial for a healthy CNS. Microglia are not only the first immune sentinels of infection, contributing to both innate and adaptive immune responses locally, but are also involved in the maintenance of brain homeostasis. Emerging data are showing new and fundamental roles for microglia in the control of neuronal proliferation and differentiation, as well as in the formation of synaptic connections. While microglia have been studied for decades, a long history of experimental misinterpretation meant that their true origins remained debated. However, recent studies on microglial origin indicate that these cells in fact arise early during development from progenitors in the embryonic yolk sac (YS) that seed the brain rudiment and, remarkably, appear to persist there into adulthood. Here, we review the history of microglial cells and discuss the latest advances in our understanding of their origin, differentiation, and homeostasis, which provides new insights into their roles in health and disease.
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Affiliation(s)
- Florent Ginhoux
- Singapore Immunology Network, Agency for Science, Technology, and ResearchSingapore
| | - Shawn Lim
- Genome Institute Singapore, Agency for Science, Technology, and ResearchSingapore
| | - Guillaume Hoeffel
- Singapore Immunology Network, Agency for Science, Technology, and ResearchSingapore
| | - Donovan Low
- Singapore Immunology Network, Agency for Science, Technology, and ResearchSingapore
| | - Tara Huber
- Genome Institute Singapore, Agency for Science, Technology, and ResearchSingapore
- Department of Biological Science, National University of SingaporeSingapore
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Microglia-derived proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta induce Purkinje neuronal apoptosis via their receptors in hypoxic neonatal rat brain. Brain Struct Funct 2012; 219:151-70. [PMID: 23262920 DOI: 10.1007/s00429-012-0491-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/21/2012] [Indexed: 01/19/2023]
Abstract
The developing cerebellum is extremely vulnerable to hypoxia which can damage the Purkinje neurons. We hypothesized that this might be mediated by tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) derived from activated microglia as in other brain areas. One-day-old rats were subjected to hypoxia following, which the expression changes of various proteins in the cerebellum including hypoxia inducible factor-1α, TNF-α, IL-1β, TNF-R1 and IL-1R1 were analyzed. Following hypoxic exposure, TNF-α and IL-1β immunoexpression in microglia was enhanced coupled by that of TNF-R1 and IL-1R1 in the Purkinje neurons. Along with this, hypoxic microglia in vitro showed enhanced release of TNF-α and IL-1β whose receptor expression was concomitantly increased in the Purkinje neurons. In addition, nitric oxide (NO) level was significantly increased in the cerebellum and cultured microglia subjected to hypoxic exposure. Moreover, cultured Purkinje neurons treated with conditioned medium derived from hypoxic microglia underwent apoptosis but the incidence was significantly reduced when the cells were treated with the same medium that was neutralized with TNF-α/IL-1β antibody. We conclude that hypoxic microglia in the neonatal cerebellum produce increased amounts of NO, TNF-α and IL-1β which when acting via their respective receptors could induce Purkinje neuron death.
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Hahn YK, Podhaizer EM, Hauser KF, Knapp PE. HIV-1 alters neural and glial progenitor cell dynamics in the central nervous system: coordinated response to opiates during maturation. Glia 2012; 60:1871-87. [PMID: 22865725 DOI: 10.1002/glia.22403] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/12/2012] [Indexed: 02/06/2023]
Abstract
HIV-associated neurocognitive disorders (HANDs) are common sequelae of human immunodeficiency virus (HIV) infection, even when viral titers are well controlled by antiretroviral therapy. Evidence in patients and animal models suggests that neurologic deficits are increased during chronic opiate exposure. We have hypothesized that central nervous system (CNS) progenitor cells in both adult and developing CNS are affected by HIV infection and that opiates exacerbate these effects. To examine this question, neural progenitors were exposed to HIV-1 Tat(1-86) in the developing brain of inducible transgenic mice and in vitro. We examined whether Tat affected the proliferation or balance of progenitor populations expressing nestin, Sox2, and Olig2. Disease relevance was further tested by exposing human-derived progenitors to supernatant from HIV-1 infected monocytes. Studies concentrated on striatum, a region preferentially targeted by HIV and opiates. Results were similar among experimental paradigms. Tat or HIV exposure reduced the proliferation of undifferentiated (Sox2(+)) progenitors and oligodendroglial (Olig2(+)) progenitors. Coexposure to morphine exacerbated the effects of Tat or HIV-1(SF162) supernatant, but partially reversed HIV-1(IIIB) supernatant effects. Populations of Sox2(+) and Olig2(+) cells were also reduced by Tat exposure, although progenitor survival was unaffected. In rare instances, p24 immunolabeling was detected in viable human progenitors by confocal imaging. The vulnerability of progenitors is likely to distort the dynamic balance among neuron/glial populations as the brain matures, perhaps contributing to reports that neurologic disease is especially prevalent in pediatric HIV patients. Pediatric disease is atypical in developed regions but remains a serious concern in resource-limited areas where infection occurs commonly at birth and through breast feeding.
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Affiliation(s)
- Yun Kyung Hahn
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia 23298-0709, USA
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Parakalan R, Jiang B, Nimmi B, Janani M, Jayapal M, Lu J, Tay SSW, Ling EA, Dheen ST. Transcriptome analysis of amoeboid and ramified microglia isolated from the corpus callosum of rat brain. BMC Neurosci 2012; 13:64. [PMID: 22697290 PMCID: PMC3441342 DOI: 10.1186/1471-2202-13-64] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 05/16/2012] [Indexed: 02/03/2023] Open
Abstract
Background Microglia, the resident immune cells of the central nervous system (CNS), have two distinct phenotypes in the developing brain: amoeboid form, known to be amoeboid microglial cells (AMC) and ramified form, known to be ramified microglial cells (RMC). The AMC are characterized by being proliferative, phagocytic and migratory whereas the RMC are quiescent and exhibit a slow turnover rate. The AMC transform into RMC with advancing age, and this transformation is indicative of the gradual shift in the microglial functions. Both AMC and RMC respond to CNS inflammation, and they become hypertrophic when activated by trauma, infection or neurodegenerative stimuli. The molecular mechanisms and functional significance of morphological transformation of microglia during normal development and in disease conditions is not clear. It is hypothesized that AMC and RMC are functionally regulated by a specific set of genes encoding various signaling molecules and transcription factors. Results To address this, we carried out cDNA microarray analysis using lectin-labeled AMC and RMC isolated from frozen tissue sections of the corpus callosum of 5-day and 4-week old rat brain respectively, by laser capture microdissection. The global gene expression profiles of both microglial phenotypes were compared and the differentially expressed genes in AMC and RMC were clustered based on their functional annotations. This genome wide comparative analysis identified genes that are specific to AMC and RMC. Conclusions The novel and specific molecules identified from the trancriptome explains the quiescent state functioning of microglia in its two distinct morphological states.
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Affiliation(s)
- Rangarajan Parakalan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Blk MD10, 4 Medical Drive, Singapore, 117597, Singapore
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Kaur C, Rathnasamy G, Ling EA. Roles of activated microglia in hypoxia induced neuroinflammation in the developing brain and the retina. J Neuroimmune Pharmacol 2012; 8:66-78. [PMID: 22367679 DOI: 10.1007/s11481-012-9347-2] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 02/09/2012] [Indexed: 12/14/2022]
Abstract
Amoeboid microglial cells (AMCs) in the developing brain display surface receptors and antigens shared by the monocyte-derived tissue macrophages. Activation of AMCs in the perinatal brain has been associated with periventricular white matter damage in hypoxic-ischemic conditions. The periventricular white matter, where the AMCs preponderate, is selectively vulnerable to hypoxia as manifested by death of premyelinating oligodendrocytes and degeneration of axons leading to neonatal mortality and long-term neurodevelopmental deficits. AMCs respond vigorously to hypoxia by producing excess amounts of inflammatory cytokines e.g. the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) along with glutamate, nitric oxide (NO) and reactive oxygen species which collectively cause oligodendrocyte death, axonal degeneration as well as disruption of the immature blood brain barrier. A similar phenomenon is observed in the hypoxic developing cerebellum in which activated AMCs induced Purkinje neuronal death through production of TNF-α and IL-1β via their respective receptors. Hypoxia is also implicated in retinopathy of prematurity in which activation of AMCs has been shown to cause retinal ganglion cell death through production of TNF-α and IL-1β and NO. Because AMCs play a pivotal role in hypoxic injuries in the developing brain affecting both neurons and oligodendrocytes, a fuller understanding of the underlying molecular mechanisms of microglial activation under such conditions would be desirable for designing of a novel therapeutic strategy for management of hypoxic damage.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, 4 Medical Drive, MD10, Singapore 117597, Singapore.
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Harry GJ, Kraft AD. Microglia in the developing brain: a potential target with lifetime effects. Neurotoxicology 2012; 33:191-206. [PMID: 22322212 DOI: 10.1016/j.neuro.2012.01.012] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 12/15/2022]
Abstract
Microglia are a heterogenous group of monocyte-derived cells serving multiple roles within the brain, many of which are associated with immune and macrophage like properties. These cells are known to serve a critical role during brain injury and to maintain homeostasis; yet, their defined roles during development have yet to be elucidated. Microglial actions appear to influence events associated with neuronal proliferation and differentiation during development, as well as, contribute to processes associated with the removal of dying neurons or cellular debris and management of synaptic connections. These long-lived cells display changes during injury and with aging that are critical to the maintenance of the neuronal environment over the lifespan of the organism. These processes may be altered by changes in the colonization of the brain or by inflammatory events during development. This review addresses the role of microglia during brain development, both structurally and functionally, as well as the inherent vulnerability of the developing nervous system. A framework is presented considering microglia as a critical nervous system-specific cell that can influence multiple aspects of brain development (e.g., vascularization, synaptogenesis, and myelination) and have a long term impact on the functional vulnerability of the nervous system to a subsequent insult, whether environmental, physical, age-related, or disease-related.
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Affiliation(s)
- G Jean Harry
- National Toxicology Program Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Zhang L, Chopp M, Zhang RL, Wang L, Zhang J, Wang Y, Toh Y, Santra M, Lu M, Zhang ZG. Erythropoietin amplifies stroke-induced oligodendrogenesis in the rat. PLoS One 2010; 5:e11016. [PMID: 20552017 PMCID: PMC2884017 DOI: 10.1371/journal.pone.0011016] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/18/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Erythropoietin (EPO), a hematopoietic cytokine, enhances neurogenesis and angiogenesis during stroke recovery. In the present study, we examined the effect of EPO on oligodendrogenesis in a rat model of embolic focal cerebral ischemia. METHODOLOGY AND PRINCIPAL FINDINGS Recombinant human EPO (rhEPO) at a dose of 5,000 U/kg (n = 18) or saline (n = 18) was intraperitoneally administered daily for 7 days starting 24 h after stroke onset. Treatment with rhEPO augmented actively proliferating oligodendrocyte progenitor cells (OPCs) measured by NG2 immunoreactive cells within the peri-infarct white matter and the subventricular zone (SVZ), but did not protect against loss of myelinating oligodendrocytes measured by cyclic nucleotide phosphodiesterase (CNPase) positive cells 7 days after stroke. However, 28 and 42 days after stroke, treatment with rhEPO significantly increased myelinating oligodendrocytes and myelinated axons within the peri-infarct white matter. Using lentivirus to label subventricular zone (SVZ) neural progenitor cells, we found that in addition to the OPCs generated in the peri-infarct white matter, SVZ neural progenitor cells contributed to rhEPO-increased OPCs in the peri-infarct area. Using bromodeoxyuridine (BrdU) for birth-dating cells, we demonstrated that myelinating oligodendrocytes observed 28 days after stroke were derived from OPCs. Furthermore, rhEPO significantly improved neurological outcome 6 weeks after stroke. In vitro, rhEPO increased differentiation of adult SVZ neural progenitor cells into oligodendrocytes and enhanced immature oligodendrocyte cell proliferation. CONCLUSIONS Our in vivo and in vitro data indicate that EPO amplifies stroke-induced oligodendrogenesis that could facilitate axonal re-myelination and lead to functional recovery after stroke.
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Affiliation(s)
- Li Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
- Department of Physics, Oakland University, Rochester, Michigan, United States of America
| | - Rui Lan Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Lei Wang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Jing Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Ying Wang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Yier Toh
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Manoranjan Santra
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Mei Lu
- Department of Biostatistics and Research Epidemiology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Zheng Gang Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
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Gómez-González B, Escobar A. Prenatal stress alters microglial development and distribution in postnatal rat brain. Acta Neuropathol 2010; 119:303-15. [PMID: 19756668 DOI: 10.1007/s00401-009-0590-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 08/28/2009] [Accepted: 09/04/2009] [Indexed: 10/24/2022]
Abstract
Stress affects microglial function and viability during adulthood and early postnatal life; however, it is unknown whether stress to the pregnant dam might alter offspring microglia. The effects of prenatal stress on microglial development and distribution in the postnatal brain were studied using Wistar rats. Prenatal stress consisting of 20 min of forced swimming occurred on embryonic days 10-20. On postnatal days 1 and 10, stressed and control pups were killed. Microglia were identified using Griffonia simplicifolia lectin and quantified in the whole encephalon. In addition, plasma corticosterone was measured in dams at embryonic day 20, and in pups on postnatal days 1 and 10. At postnatal day 1, there was an increase in number of ramified microglia in the parietal, entorhinal and frontal cortices, septum, basal ganglia, thalamus, medulla oblongata and internal capsule in the stressed pups as compared to controls, but also there was a reduction of amoeboid microglia and the total number of microglia in the corpus callosum. By postnatal day 10, there were no differences in the morphologic type or the distribution of microglia between the prenatal stress and control groups, except in the corpus callosum; where prenatal stress decreased the number of ramified microglia. The stress procedure was effective in producing plasma rise in corticosterone levels of pregnant rats at embryonic day 20 when compared to same age controls. Prenatal stress reduced the number of immature microglia and promoted an accelerated microglial differentiation into a ramified form. These findings may be related to an increase in plasma corticosterone in the pregnant dam.
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Affiliation(s)
- Beatriz Gómez-González
- Department of Cell Biology and Physiology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, Mexico D.F., Mexico.
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Shibuya S, Yamamoto T, Itano T. Glial and axonal regeneration following spinal cord injury. Cell Adh Migr 2009; 3:99-106. [PMID: 19372750 DOI: 10.4161/cam.3.1.7372] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Spinal cord injury (SCI) has been regarded clinically as an irreversible damage caused by tissue contusion due to a blunt external force. Past research had focused on the analysis of the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as tissue damage and neural cell death associated with secondary injury. Recent studies, however, have proven that neural stem (progenitor) cells are also present in the brain and spinal cord of adult mammals including humans. Analyses using spinal cord injury models have also demonstrated active dynamics of cells expressing several stem cell markers, and methods aiming at functional reconstruction by promoting the potential self-regeneration capacity of the spinal cord are being explored. Furthermore, reconstruction of the neural circuit requires not only replenishment or regeneration of neural cells but also regeneration of axons. Analysis of the tissue microenvironment after spinal cord injury and research aiming to remove axonal regeneration inhibitors have also made progress. SCI is one of the simplest central nervous injuries, but its pathogenesis is associated with diverse factors, and further studies are required to elucidate these complex interactions in order to achieve spinal cord regeneration and functional reconstruction.
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Affiliation(s)
- Sei Shibuya
- Department of Orthopaedic Surgery, School of Medicine, Kagawa University, Miki-cho, Kagawa, Japan
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Tambuyzer BR, Ponsaerts P, Nouwen EJ. Microglia: gatekeepers of central nervous system immunology. J Leukoc Biol 2008; 85:352-70. [DOI: 10.1189/jlb.0608385] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Goings GE, Kozlowski DA, Szele FG. Differential activation of microglia in neurogenic versus non-neurogenic regions of the forebrain. Glia 2006; 54:329-42. [PMID: 16862532 DOI: 10.1002/glia.20381] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Proliferation decreases in the neurogenic subventricular zone (SVZ) of mice after aspiration lesions of the cerebral cortex. We hypothesized that microglial activation may contribute to this given microglial activation attenuates neurogenesis in the hippocampus. Using CD45, CD11b, IB4, and IL-6 immunohistochemistry (IHC), BrdU IHC, and fluorescent bead tracking of peripheral monocytes into the brain, we compared microglial activation in the SVZ to non-neurogenic forebrain regions. SVZ microglia exhibited greater constitutive activation and proliferation than did microglia in non-neurogenic regions. In contrast to the SVZ, the dentate gyrus (DG) contained relatively few CD45(+) cells. After aspiration cerebral cortex lesions, microglia became activated in the cerebral cortex, corpus callosum, and striatum. SVZ microglial activation did not increase, and similarly, microglia in the DG were less activated after injury than in adjacent non-neurogenic regions. We next showed that SVZ microglia are not categorically refractory to activation, since deep cortical contusion injuries increased SVZ microglial activation. Macrophages migrate into the brain during development, but it is unclear if this is recapitulated after injury. Infiltration of microbead-labeled macrophages into the brain did not change after injury, but resident SVZ microglia were induced to migrate toward the injury. Our data show that both constitutive and postlesion levels of microglial activation differ between neurogenic and non-neurogenic regions.
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Affiliation(s)
- Gwendolyn E Goings
- Children's Memorial Research Center, Neurobiology Program, Children's Memorial Hospital, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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43
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Billiards SS, Haynes RL, Folkerth RD, Trachtenberg FL, Liu LG, Volpe JJ, Kinney HC. Development of microglia in the cerebral white matter of the human fetus and infant. J Comp Neurol 2006; 497:199-208. [PMID: 16705680 DOI: 10.1002/cne.20991] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although microglial activation may be an initial beneficial response to a variety of insults, prolonged activation can release toxic substances and lead to cell death. Microglial activation secondary to hypoxia-ischemia and/or infection in immature cerebral white matter is important in the pathogenesis of periventricular leukomalacia (PVL), the major pathological substrate of cerebral palsy in the premature infant. We hypothesize that a transient overexpression in activated microglial density occurs normally in the cerebral white matter of the human fetus during the peak window of vulnerability for PVL. Such an increase could render this region susceptible to insults that cause prolonged microglial activation, as conceptualized in PVL. To examine the developmental profile of microglia in the human fetus and infant brain, immunocytochemistry with microglial specific markers were used in 23 control (non-PVL) cases ranging from 20 to 183 postconceptional (PC) weeks. Tomato lectin, used to identify microglial morphology, revealed that the cerebral white matter of the human fetus and infant is densely populated with intermediate and amoeboid microglia; the latter is indicative of an activated state. Quantitative analysis with CD68 showed increased density of activated microglia in the cerebral white matter of the fetus (<37 PC weeks) relative to the neonate/infant (> or =37 PC weeks) and to the overlying cortex of either age group (P = 0.01). The primary finding of a transient, developmental-dependent overabundance of CD68-activated microglia in the cerebral white matter of the fetus suggests a potential "priming" of this area for diverse brain insults characterized by activation of microglia, particularly PVL. J.
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Affiliation(s)
- Saraid S Billiards
- Department of Pathology, Children's Hospital Boston and Harvard Medical School, MA 02115, USA.
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44
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Monier A, Evrard P, Gressens P, Verney C. Distribution and differentiation of microglia in the human encephalon during the first two trimesters of gestation. J Comp Neurol 2006; 499:565-82. [PMID: 17029271 DOI: 10.1002/cne.21123] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We describe the topographical distribution of microglial subpopulations during development of the human diencephalon and telencephalon. Brains from embryos and fetuses age 5-23.5 gestational weeks (gw) were subjected to single- and double-immunolabeling for lectin RCA-1 (Ricinus Communis Agglutinin 1), Iba1 (a microglial marker), CD68 (specific of macrophages), CD45 (marker for mononucleate cells of hematopoietic lineage), CD34 (expressed on endothelial cells), and MIB1 and Ki67 (markers for cell proliferation). At 5.5 gw the first intracerebral microglial cells were seen close to the meninges and choroid plexus near the di-telencephalic fissure. They were amoeboid and positive for Iba1, CD45, and RCA-1, whereas cells in the deep parenchyma expressed Iba1/CD68/RCA-1 and constituted clusters. In the developing diencephalon, microglial clusters were located in junctional regions of the white matter anlagen, most notably at the junctions of the internal capsule with the thalamic projections, the external capsule, and the cerebral peduncle. In the cortical anlagen, Iba1+/RCA-1/CD68+/CD45+ cells accumulated at 10-12 gw, constituting a tangential band at the junction between the cortical plate and the subplate. Between 10 and 16 gw microglial clusters increased markedly in size and cellular density. Contact between Iba1+ microglia and CD34+ blood vessels was clearly visible from 10-12 gw onward, first in microglial clusters of the white matter anlagen and subsequently throughout the parenchyma. From the middle of the second trimester onward microglial cells colonized the entire cerebral parenchyma, developed a ramified morphology, and downregulated their surface antigens, but remained more numerous in the white matter.
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45
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Hirasawa T, Ohsawa K, Imai Y, Ondo Y, Akazawa C, Uchino S, Kohsaka S. Visualization of microglia in living tissues using Iba1-EGFP transgenic mice. J Neurosci Res 2005; 81:357-62. [PMID: 15948177 DOI: 10.1002/jnr.20480] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microglia are thought to play important roles not only in repairing injured tissue but in regulating neuronal activity, and visualizing the cells is very useful as a means of further investigating the function of microglia in vivo. We previously cloned the ionized calcium-binding adaptor molecule 1 (Iba1) gene, which is expressed selectively in microglia/microphages. To generate new transgenic mice to visualize microglia with enhanced green fluorescent protein (EGFP), we here constructed a plasmid carrying EGFP cDNA under control of the Iba1 promoter. This construct was injected into C57B/6 mouse zygotes, and the Iba1-EGFP transgenic line was developed. Fluorescent in-situ hybridization analysis revealed that the Iba1-EGFP transgene was located on chromosome 11D. No obvious defects were observed during development or in adulthood, and the EGFP fluorescence remained invariant over the course of at least four generations. Judging from the immunoreactivity with anti-Iba1 antibody, all EGFP-positive cells in the adult brain were ramified microglia. In the developing transgenic embryos, EGFP signals were detected as early as embryonic Day 10.5. The most prominent EGFP signals were found in forebrain, spinal cord, eye, foreleg, yolk sac, liver, and vessel walls. At postnatal Day 6, clear EGFP signals were observed in the supraventricular corpus callosum, known as "fountain of microglia", where ameboid microglia migrate into the brain parenchyma and mature into ramified microglia. Iba1-EGFP transgenic mice thus permit observation of living microglia under a fluorescence microscope and provide a useful tool for studying the function of microglia in vivo.
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Affiliation(s)
- T Hirasawa
- Department of Neurochemistry, National Institute of Neuroscience, Kodaira, Tokyo, Japan
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46
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Rezaie P, Dean A, Male D, Ulfig N. Microglia in the cerebral wall of the human telencephalon at second trimester. ACTA ACUST UNITED AC 2004; 15:938-49. [PMID: 15483047 DOI: 10.1093/cercor/bhh194] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We have recently begun to gain a clearer understanding of the phasing and patterns of colonization of the developing human brain by microglia. In this study we investigated the distribution, morphology and phenotype of microglia specifically within the wall of the human telencephalon from 12 to 24 gestational weeks (gw), a period that corresponds to the development of thalamocortical fibres passing through the transient subplate region of the developing cerebral wall. Sections from a total of 45 human fetal brains were immunoreacted to detect CD68 and MHC class II antigens and histochemically reacted with RCA-1 and tomato lectins. These markers were differentially expressed by anatomically discrete populations of microglia in the cerebral wall: two cell populations were noted during the initial phase of colonization (12-14 gw): (i) CD68++ RCA-1+ MHC II- amoeboid cells aligned within the subplate, and (ii) RCA-1++ CD68- MHC II- progenitors in the marginal layer and lower cortical plate that progressively ramified within the subplate, without seemingly passing through an 'amoeboid' state. At this stage microglia were largely absent from the germinal layers and the intermediate zone. From 14 to 15 gw, however, MHC class II positive cells were also detected within germinal layers and in the corpus callosum, and these cells, which coexpressed CD68 antigen (a marker associated with phagocytosis), further populated the lower half of the telencephalon from 18 to 24 gw. These findings are discussed in relation to developmental events that take place during the second trimester within the wall of the telencephalon.
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Affiliation(s)
- Payam Rezaie
- Department of Biological Sciences, Faculty of Science, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.
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47
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Zhang C, Tso MOM. Characterization of activated retinal microglia following optic axotomy. J Neurosci Res 2003; 73:840-5. [PMID: 12949910 DOI: 10.1002/jnr.10713] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Microglia are prominently involved in neural degenerative diseases of the CNS and the retina. In this study, we determined the activation and phagocytotic function of different subtypes of retinal microglial cells at 1 week and 1 month following optic axotomy. Fluorescent DiI crystals were placed at the stumps of the cut optic nerves of Lewis rats to retrolabel retinal ganglion cells. Microglial cells were indirectly labeled as they phagocytosed the dye particles in the dying ganglion cells. OX-42, 5D4, ED1, and OX-6 antibodies were used for immunohistochemical study. The OX-42- and 5D4-positive microglial cells were increased in the inner retinal layers after optic axotomy. The increase of OX-42-positive cells was considerably greater than that of 5D4-positive cells. The 5D4-positive cells were ramified in shape, whereas OX-42-positive cells were ameboid and ovoid. Both 5D4- and OX-42-positive cells phagocytosed dying ganglion cells at 1 week and 1 month after axotomy. Scattered ameboid ED1-positive cells were detected in the normal retina and showed phagocytotic activity at 1 month after optic axotomy. The number of ED1-positive cells in the retina was unchanged after axotomy. In optic axotomy, three types of microglial cells were activated, namely, 5D4-positive ramified cells and OX-42- and ED1-positive ameboid cells. All of them exhibited the phagocytosis of dying ganglion cells. Insofar as the blood-retinal barrier presumably remained intact in optic axotomy, the OX-42- and 5D4-positive cells might derive from resident microglial cells. The ED1-positive cells, presumably recently blood-borne macrophage in the CNS, remained the same number in the axotomized retina.
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Affiliation(s)
- Cheng Zhang
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9238, USA.
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48
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Dalmau I, Vela JM, González B, Finsen B, Castellano B. Dynamics of microglia in the developing rat brain. J Comp Neurol 2003; 458:144-57. [PMID: 12596255 DOI: 10.1002/cne.10572] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Entrance of mesodermal precursors into the developing CNS is the most well-accepted origin of microglia. However, the contribution of proliferation and death of recruited microglial precursors to the final microglial cell population remains to be elucidated. To investigate microglial proliferation and apoptosis during development, we combined proliferating cell nuclear antigen (PCNA) immunohistochemistry, in situ detection of nuclear DNA fragmentation (TUNEL), and caspase-3 immunohistochemistry with tomato lectin histochemistry, a selective microglial marker. The study was carried out in Wistar rats from embryonic day (E) 16 to postnatal day (P) 18 in cerebral cortex, subcortical white matter, and hippocampus. Proliferating microglial cells were found at all ages in the three brain regions and represented a significant fraction of the total microglial cell population. The percentage of microglia expressing PCNA progressively increased from the embryonic period (25-51% at E16) to a maximum at P9, when the great majority of microglia expressed PCNA (92-99%) in all the brain regions analyzed. In spite of the remarkable proliferation and expansion of the microglial population with time, the density of microglia remained quite constant in most brain regions because of the considerable growth of the brain during late prenatal and early postnatal periods. In contrast, apoptosis of microglia was detected only at certain times and was restricted to some ameboid cells in white matter and primitive ramified cells in gray matter, representing a small fraction of the microglial population. Therefore, our results point to proliferation of microglial precursors in the developing brain as a physiological mechanism contributing to the acquisition of the adult microglial cell population. In contrast, microglial apoptosis occurs only locally at certain developmental stages and thus seems less crucial for the establishment of the final density of microglia.
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Affiliation(s)
- Ishar Dalmau
- Departmet of Histology, Faculty of Medicine, Autonomous University of Barcelona, E-08193-Bellaterra, Spain
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49
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Rochefort N, Quenech'du N, Watroba L, Mallat M, Giaume C, Milleret C. Microglia and astrocytes may participate in the shaping of visual callosal projections during postnatal development. JOURNAL OF PHYSIOLOGY, PARIS 2002; 96:183-92. [PMID: 12445895 DOI: 10.1016/s0928-4257(02)00005-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the adult cat, axons running through the corpus callosum interconnect the border between the visual cortical areas 17 and 18 (A17 and A18) of both hemispheres. This specific pattern emerges during postnatal development, under normal viewing conditions (NR), from the elimination of initially exuberant callosal projections. In contrast, if the postnatal visual experience is monocular from birth (MD), juvenile callosal projections are stabilised throughout A17 and A18. The present study aimed at using such a model in vivo to find indications of a contribution of glial cells in the shaping of projections in the developing CNS through interactions with neurones, both in normal and pathological conditions. As a first stage, the distribution and the morphology of microglial cells and astrocytes were investigated from 2 weeks to adulthood. Microglial cells, stained with isolectin-B4, were clustered in the white matter below A17 and A18. Until one month, these clustered cells displayed an ameboid morphology in NR group, while they were more ramified in MD animals. Their phenotype thus depends on the postnatal visual experience, which indicates that microglial cells may interact with axons of visual neurones. It also suggests that they may differentially contribute to the elimination and the stabilisation of juvenile exuberant callosal fibres in NR and MD animals respectively. Beyond one month, microglial cells were very ramified in both experimental groups. Astrocytes were labelled with a GFAP-antibody. The distributions of connexins 43 (Cx43) and 30 (Cx30), the main proteic components of gap junction channels in astrocytes, were also investigated using specific antibodies. Both in NR and MD groups, until 1 month, GFAP-positive astrocytes and Cx43 were mainly localised within the subcortical white matter. Then GFAP, Cx43 and Cx30 stainings progressively appeared within the cortex, throughout A17 and A18 but with a differential laminar expression according to the age. Thus, the distributions of both astrocytes and connexins changed with age; however, the monocular occlusion had no visible effect. This suggests that astrocytes may contribute to the postnatal development of neuronal projections to the primary visual cortex, including visual callosal projections.
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Affiliation(s)
- N Rochefort
- Laboratoire de Physiologie de la Perception et de l'Action, UMR 7124, Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
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50
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Naito T, Yoshioka H, Yasuda Y. Migration and Proliferation of Motile Immature Glial Cells in the Developing Cerebral Cortex of Infantile Rat. Acta Histochem Cytochem 2002. [DOI: 10.1267/ahc.35.407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Takeshi Naito
- Department of Pediatrics, Kyoto Prefectural University of Medicine
- Cell Biology Section, Division of Basic Research, Louis Pasteur Center for Medical Research
| | - Hiroshi Yoshioka
- Department of Pediatrics, Kyoto Prefectural University of Medicine
| | - Yuko Yasuda
- Cell Biology Section, Division of Basic Research, Louis Pasteur Center for Medical Research
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