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Gansemer BM, Rahman MT, Zhang Z, Green SH. Spiral ganglion neuron degeneration in aminoglycoside-deafened rats involves innate and adaptive immune responses not requiring complement. Front Mol Neurosci 2024; 17:1389816. [PMID: 38840777 PMCID: PMC11151750 DOI: 10.3389/fnmol.2024.1389816] [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: 02/22/2024] [Accepted: 04/29/2024] [Indexed: 06/07/2024] Open
Abstract
Spiral ganglion neurons (SGNs) transmit auditory information from cochlear hair cells to the brain. SGNs are thus not only important for normal hearing, but also for effective functioning of cochlear implants, which stimulate SGNs when hair cells are missing. SGNs slowly degenerate following aminoglycoside-induced hair cell loss, a process thought to involve an immune response. However, the specific immune response pathways involved remain unknown. We used RNAseq to gain a deeper understanding immune-related and other transcriptomic changes that occur in the rat spiral ganglion after kanamycin-induced deafening. Among the immune and inflammatory genes that were selectively upregulated in deafened spiral ganglia, the complement cascade genes were prominent. We then assessed SGN survival, as well as immune cell numbers and activation, in the spiral ganglia of rats with a CRISPR-Cas9-mediated knockout of complement component 3 (C3). Similar to previous findings in our lab and other deafened rodent models, we observed an increase in macrophage number and increased expression of CD68, a marker of phagocytic activity and cell activation, in macrophages in the deafened ganglia. Moreover, we found an increase in MHCII expression on spiral ganglion macrophages and an increase in lymphocyte number in the deafened ganglia, suggestive of an adaptive immune response. However, C3 knockout did not affect SGN survival or increase in macrophage number/activation, implying that complement activation does not play a role in SGN death after deafening. Together, these data suggest that both innate and adaptive immune responses are activated in the deafened spiral ganglion, with the adaptive response directly contributing to cochlear neurodegeneration.
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Affiliation(s)
| | | | | | - Steven H. Green
- Department of Biology, University of Iowa, Iowa City, IA, United States
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2
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Kulkarni B, Cruz-Martins N, Kumar D. Microglia in Alzheimer's Disease: An Unprecedented Opportunity as Prospective Drug Target. Mol Neurobiol 2022; 59:2678-2693. [PMID: 35149973 DOI: 10.1007/s12035-021-02661-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/20/2021] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is an ever more common neurodegenerative disease among the elderly, characterized by recurrent neuroinflammation and amyloid beta (Aβ) accumulation in the brain parenchyma. Recent genome-wide association studies (GWAS) have shown a distinct role for the innate immune system in AD, with microglia playing a key role. The function of microglial cells is stringently regulated by the neighboring microenvironment in the brain. Upon interruption in diseases, like AD, it demonstrates neurotoxic and neuroprotective action by M1 (neurotoxic) and M2 (neuroprotective) microglial phenotypes, respectively, in the brain. Microglial cells on activation by complement factors, toll-like receptors, and genetic variants result in Aβ' phagocytosis, synaptic pruning, and reactivation of complement pathway. Recent studies have demonstrated the presence of potential therapeutic targets in microglial cells. Immune receptors revealed on microglia as potential drug targets can be paired immunoglobulin-like type 2 receptor (PILR), CD3358, and triggering receptor expressed on myeloid cells 2 (TREM2), as they can have impact on late-onset AD occurrence and progression. Thus, targeting these receptors can accentuate the beneficial effects of microglial cells required to decelerate the progression of AD. This review emphasizes the microglial phenotypes, its function in AD brain, and potential immunological and therapeutic targets to fight this highly progressive neurodegenerative disorder.
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Affiliation(s)
- Bhargavi Kulkarni
- Poona College of Pharmacy, Bharati Vidyapeeth (Deemed To Be University) Erandawane, Pune, 411038, Maharashtra, India
| | - Natália Cruz-Martins
- Institute of Research and Advanced, Training in Health Sciences and Technologies (CESPU), Rua Central de Gandra, 1317, 4585-116, Gandra, PRD, Portugal. .,Faculty of Medicine, University of Porto, Alameda Prof. Hernani Monteiro, 4200-319, Porto, Portugal. .,Institute for Research and Innovation in Health (i3S), University of Porto, 4200-135, Porto, Portugal.
| | - Dileep Kumar
- Poona College of Pharmacy, Bharati Vidyapeeth (Deemed To Be University) Erandawane, Pune, 411038, Maharashtra, India.
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3
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Boche D, Gordon MN. Diversity of transcriptomic microglial phenotypes in aging and Alzheimer's disease. Alzheimers Dement 2022; 18:360-376. [PMID: 34223696 PMCID: PMC9059230 DOI: 10.1002/alz.12389] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 04/28/2021] [Accepted: 05/02/2021] [Indexed: 02/03/2023]
Abstract
The morphological plasticity of microglia has fascinated neuroscientists for 100 years. Attempts to classify functional phenotypes are hampered by similarities between endogenous brain microglia and peripheral myeloid cells that can enter the brain under pathological conditions. Recent advances in single-cell -omic methodologies have led to an explosion of data regarding gene expression in microglia. Herein, we review the diversity of microglial phenotypes in healthy brains, aging, and Alzheimer's disease (AD); identify knowledge gaps in the body of evidence; and suggest areas in which new knowledge would be useful. Data from human samples and mouse models are compared and contrasted. Understanding the molecular complexity of the microglial response repertoire will suggest new avenues for therapeutic treatments in AD.
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Affiliation(s)
- Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Marcia N. Gordon
- Translational Neuroscience, Michigan State University College of Human Medicine, Grand Rapids, MI, USA,corresponding author: Marcia N. Gordon, PhD, Michigan State University GRRC, 400 Monroe Ave NW, Grand Rapids, MI, 49503 USA, , Telephone: (616) 234-2837
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4
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Ohgomori T, Iinuma K, Yamada J, Jinno S. A unique subtype of ramified microglia associated with synapses in the rat hippocampus. Eur J Neurosci 2021; 54:4740-4754. [PMID: 34110047 DOI: 10.1111/ejn.15330] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 12/13/2022]
Abstract
To date, a number of studies have reported the heterogeneity of activated microglia. However, there is increasing evidence suggests that ramified, so-called resting, microglia may also be heterogeneous, and they may play diverse roles in normal brain homeostasis. Here, we found that both 5D4 keratan sulfate epitope-positive (5D4+ ) and 5D4-negative (5D4- ) microglia coexisted in the hippocampus of normal rats, while all microglia were negative for the 5D4 epitope in the hippocampus of normal mice. We thus aimed to determine the potential heterogeneity of microglia related to the 5D4 epitope in the normal rat hippocampus. The optical disector analysis showed that the densities of 5D4+ microglia were higher in the stratum oriens of the CA3 region than in other layers and regions. Although both 5D4+ and 5D4- microglia exhibited a ramified morphology, the three-dimensional reconstruction analysis showed that the node numbers, end numbers, and complexity of processes were higher in 5D4+ than in 5D4- microglia. The linear discriminant analysis showed that 5D4+ and 5D4- microglia can be classified into distinct morphometric subtypes. The ratios of contact between synaptic boutons and microglial processes were higher in 5D4+ than in 5D4- microglia. The gene expressions of pro-inflammatory cytokine interleukin-1β and purinergic receptor P2Y12 (P2Y12 R) were higher in 5D4+ than in 5D4- microglia. Together, these results indicate that at least two different subtypes of ramified microglia coexist in the normal rat hippocampus and also suggest that 5D4+ microglia may represent a unique subtype associated with synapses.
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Affiliation(s)
- Tomohiro Ohgomori
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Department of Rehabilitation, Osaka Kawasaki Rehabilitation University, Kaizuka, Japan
| | - Kyoko Iinuma
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Jun Yamada
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shozo Jinno
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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5
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Bachiller S, Jiménez-Ferrer I, Paulus A, Yang Y, Swanberg M, Deierborg T, Boza-Serrano A. Microglia in Neurological Diseases: A Road Map to Brain-Disease Dependent-Inflammatory Response. Front Cell Neurosci 2018; 12:488. [PMID: 30618635 PMCID: PMC6305407 DOI: 10.3389/fncel.2018.00488] [Citation(s) in RCA: 416] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/29/2018] [Indexed: 12/12/2022] Open
Abstract
Microglia represent a specialized population of macrophages-like cells in the central nervous system (CNS) considered immune sentinels that are capable of orchestrating a potent inflammatory response. Microglia are also involved in synaptic organization, trophic neuronal support during development, phagocytosis of apoptotic cells in the developing brain, myelin turnover, control of neuronal excitability, phagocytic debris removal as well as brain protection and repair. Microglial response is pathology dependent and affects to immune, metabolic. In this review, we will shed light on microglial activation depending on the disease context and the influence of factors such as aging, environment or cell-to-cell interaction.
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Affiliation(s)
- Sara Bachiller
- Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Itzia Jiménez-Ferrer
- Translational Neurogenetics Unit, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Agnes Paulus
- Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Yiyi Yang
- Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Maria Swanberg
- Translational Neurogenetics Unit, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
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6
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De Biase LM, Bonci A. Region-Specific Phenotypes of Microglia: The Role of Local Regulatory Cues. Neuroscientist 2018; 25:314-333. [PMID: 30280638 DOI: 10.1177/1073858418800996] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Microglia are ubiquitous, macrophage like cells within the central nervous system (CNS) that play critical roles in supporting neuronal health and viability. They can also influence neuronal membrane properties and synaptic connectivity, positioning microglia as key cellular players in both physiological and pathological contexts. Microglia have generally been assumed to be equivalent throughout the CNS, but accumulating evidence indicates that their properties vary substantially across distinct CNS regions. In comparison to our understanding of neuronal diversity and its functional importance, our knowledge about causes and consequences of microglial regional heterogeneity is extremely limited. To fully understand how microglia influence the function of specific neuronal populations and shape heightened susceptibility of some neurons to damage and disease, greater focus on microglial heterogeneity is needed.
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Affiliation(s)
- Lindsay M De Biase
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Antonello Bonci
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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7
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Neonatal rat microglia derived from different brain regions have distinct activation responses. ACTA ACUST UNITED AC 2013; 7:5-16. [PMID: 22857737 DOI: 10.1017/s1740925x12000154] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The regional heterogeneity of neuronal phenotypes is a well-known phenomenon. Whether or not glia derived from different brain regions are phenotypically and functionally distinct is less clear. Here, we show that microglia, the resident immune cells of the brain, display region-specific responses for activating agents including glutamate (GLU), lipopolysaccharide (LPS) and adenosine 5'-triphosphate (ATP). Primary microglial cultures were prepared from brainstem (Brs), cortex (Ctx), hippocampus (Hip), striatum (Str) and thalamus (Thl) of 1-day-old rats and were shown to upregulate the release of nitric oxide (NO) and brain-derived neurotrophic factor (BDNF) in a region- and activator-specific manner. With respect to ATP specifically, ATP-induced changes in microglial tumor necrosis factor-α (TNF-α) release, GLU uptake and purinergic receptor expression were also regionally different. When co-cultured with hypoxia (Hyp)-injured neurons, ATP-stimulated microglia from different regions induced different levels of neurotoxicity. These region-specific responses could be altered by pre-conditioning the microglia in a different neurochemical milieu, with taurine (TAU) being one of the key molecules involved. Together, our results demonstrate that microglia display a regional heterogeneity when activated, and this heterogeneity likely arises from differences in the environment surrounding the microglia. These findings present an additional mechanism that may help to explain the regional selectiveness of various brain pathologies.
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8
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Olah M, Raj D, Brouwer N, De Haas AH, Eggen BJL, Den Dunnen WFA, Biber KPH, Boddeke HWGM. An optimized protocol for the acute isolation of human microglia from autopsy brain samples. Glia 2011; 60:96-111. [PMID: 21989594 DOI: 10.1002/glia.21251] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 09/12/2011] [Indexed: 12/27/2022]
Abstract
Microglia are increasingly recognized to be crucially involved in the maintenance of tissue homeostasis of the brain and spinal cord. Not surprisingly is therefore the growing scientific interest in the microglia phenotypes associated with various physiological and pathological processes of the central nervous system. Until recently the investigation of these phenotypes was hindered by the lack of an isolation protocol that (without an extended culturing period) would offer a microglia population of high purity and yield. Thus, our objective was to establish a rapid and efficient method for the isolation of human microglia from postmortem brain samples. We tested multiple elements of already existing protocols (e.g., density separation, immunomagnetic bead separation) and combined them to minimize preparation time and maximize yield and purity. The procedure presented in this article enables acute isolation of human microglia from autopsy (and biopsy) samples with a purity and yield that is suitable for downstream applications, such as protein and gene expression analysis and functional assays. Moreover, the present protocol is appropriate for the isolation of microglia from autopsy samples irrespective of the neurological state of the brain or specific brain regions and (with minor modification) could be even used for the isolation of microglia from human glioma tissue.
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Affiliation(s)
- Marta Olah
- Section Medical Physiology, Department of Neuroscience, UMCG-RuG, Groningen, The Netherlands
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9
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Simcock JW, Penington AJ, Morrison WA, Thompson EW, Mitchell GM. Endothelial Precursor Cells Home to a Vascularized Tissue Engineering Chamber by Application of the Angiogenic Chemokine CXCL12. Tissue Eng Part A 2009; 15:655-64. [DOI: 10.1089/ten.tea.2007.0438] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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10
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de Haas AH, Boddeke HWGM, Biber K. Region-specific expression of immunoregulatory proteins on microglia in the healthy CNS. Glia 2008; 56:888-94. [PMID: 18338796 DOI: 10.1002/glia.20663] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In accordance with a high degree of spatial organization in the central nervous system (CNS), most CNS diseases display a regional distribution. Although microglia have been established as key players in various CNS diseases, it is not yet clear whether microglia display region-specific properties. Therefore, this study aimed to evaluate the existence of distinct microglia phenotypes in various regions of the healthy, adult mouse CNS. Using ex vivo flow cytometric analysis surface expression of CD11b, CD40, CD45, CD80, CD86, F4/80, TREM-2b, MHCII, CXCR3, CCR9, and CCR7 were analyzed. Most of these immunoregulatory markers were found on microglia and showed significant region-specific differences in expression levels. These findings considerably corroborate the existence of immunological diversity among microglia in the healthy, unchallenged CNS of adult mice.
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Affiliation(s)
- Alexander H de Haas
- Department of Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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11
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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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12
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Meeuwsen S, Bsibsi M, Persoon-Deen C, Ravid R, van Noort JM. Cultured human adult microglia from different donors display stable cytokine, chemokine and growth factor gene profiles but respond differently to a pro-inflammatory stimulus. Neuroimmunomodulation 2005; 12:235-45. [PMID: 15990454 DOI: 10.1159/000085655] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 02/22/2005] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Brain microglia are highly responsive cells in the central nervous system that exert key functions in host defense as well as in neuroprotection and regeneration. In this study the gene expression profiles for 268 cytokines, chemokines, growth factors and their receptors were examined in cultures of purified human adult microglia, using cDNA array profiling. METHODS Microglia from 9 different donors were compared, also following challenge of such microglia with the pro-inflammatory cytokines TNF-alpha and IFN-gamma. RESULTS A stable pattern was observed of genes abundantly expressed in the different cultures under standard conditions. Genes abundantly expressed in all microglia cultures include CCL2 (MCP-1), thymosin beta-10, migration-inhibitory factor-related protein 8 (MRP8), MRP14, corticotropin-releasing factor receptor 1 and endothelin 2. Abundant gene products novel to microglia were neuromodulin (GAP43) and Flt3 ligand. Yet, treatment with TNF-alpha and IFN-gamma led to widely different response profiles among the different cultures. CONCLUSION These data show a surprising level of heterogeneity among human adult microglia cultures in their response to a pro-inflammatory stimulus despite the standardized methodology to examine this response.
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Affiliation(s)
- Sonja Meeuwsen
- Division Biomedical Research, TNO Prevention and Health, Leiden, The Netherlands
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13
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Jiang-Shieh YF, Wu CH, Chang ML, Shieh JY, Wen CY. Regional heterogeneity in immunoreactive macrophages/microglia in the rat pineal gland. J Pineal Res 2003; 35:45-53. [PMID: 12823613 DOI: 10.1034/j.1600-079x.2003.00054.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Using specific macrophage antibodies (OX-42, OX-6, ED-1 and ED-2), this study examined the distribution of macrophages/microglia in the pineal gland of adult rats. Except for ED-2, all antibodies labeled distinct subpopulations of macrophages/microglia in the gland; ED-2 labeling was hardly detectable. The quantitative study showed that the pineal macrophages/microglia (PMM) expressing complement type 3 receptors (OX-42) were more numerous than those expressing the major histocompatibility complex class II antigen (OX-6) or unknown cytoplasmic/lysosomal antigens (ED-1). The PMM were ubiquitous, especially the OX-42 labeled cells which were distributed from the dorsal to the ventral aspect of the gland. The macrophages/microglia labeled with OX-6 or ED-1 were localized mainly in the intermediate portion of the pineal gland. Immunolabeled cells were sparsely distributed in the distal portion of the pineal gland. A notable feature was that the OX-6 labeled macrophages/microglia showed a proximal-distal gradient in cell density. Another interesting feature was the occurrence of prominent cell aggregations around the larger blood vessels. These cells were mostly round and exhibited different immunoreactivity. Confocal microscopic study with triple immunolabeling further revealed that individual PMM cell possessed two or more different antigens (ED-1+/OX-6+, OX-42+/OX-6+ or OX-42+/ED-1+). Remarkably, a large population co-expressed ED-1+/OX-6+/OX-42+. The present results show that the expression of immunoreactive molecules in PMM varies in topographical distribution of the cells. It is suggested that this may be linked to their immunoregulatory functions in the gland.
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Affiliation(s)
- Ya Fen Jiang-Shieh
- Department of Anatomy, College of Medicine, National Cheng Kung University, Tainan Taiwan
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14
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Chang CY, Chien HF, Jiangshieh YF, Wu CH. Microglia in the olfactory bulb of rats during postnatal development and olfactory nerve injury with zinc sulfate: a lectin labeling and ultrastrucutural study. Neurosci Res 2003; 45:325-33. [PMID: 12631468 DOI: 10.1016/s0168-0102(02)00236-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Using isolectin (GSA I-B4) as a marker, this study examined the possible alterations of lectin-labeled membranous glycoproteins in microglial cells in the olfactory bulb of normal development and under experimentally induced degeneration. In light microscopy, several morphological types of microglial cells representing different degrees of cell differentiation were distributed in the bulb laminae. A gradient of microglial differentiation extending from the intermediate to superficial and intermediate to deep occurs in the bulb layers. The differentiation gradient and lectin labeling pattern of microglial cells in the developing bulb resembled those in other areas of the brain tissues. Differentiating microglia showed a gradual diminution of lectin staining when the nascent round cells transformed into the mature ramified cells. Microglia in the external plexiform layer of the olfactory bulb were the first to mature and the cells expressed very weak lectin reactivity. In mature or adult rats, some microglial cells showing intense lectin labeling were observed in the olfactory nerve layer, granule cell layer and subependymal layer. Ultrastructurally, lectin labeling was localized at the trans saccules of the Golgi apparatus. Microglial cells in other bulb laminae, however, exhibited a negative reaction for the isolectin at the Golgi apparatus. Following intranasal irrigation of zinc sulfate, some microglial cells in the olfactory nerve layer and glomerular layer were activated to become phagocytic cells with increased lectin labeling at their ramified processes. GSA I-B4 staining was also localized at their trans saccules of the Golgi apparatus. The lectin labeling pattern of these phagocytic cells resembled that of differentiating microglia in postnatal bulbs, suggesting that bulb microglia in the lesioned sites were activated through cell dedifferentiation into macrophages.
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Affiliation(s)
- C Y Chang
- Department of Anatomy, Taipei Medical University, Taipei, Taiwan, ROC
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15
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Ling EA, Ng YK, Wu CH, Kaur C. Microglia: its development and role as a neuropathology sensor. PROGRESS IN BRAIN RESEARCH 2001; 132:61-79. [PMID: 11545023 DOI: 10.1016/s0079-6123(01)32066-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- E A Ling
- Department of Anatomy, Faculty of Medicine, National University of Singapore, MD 10, 4 Medical Drive, Singapore 117597, Singapore.
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16
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Wu CH, Chien HF, Chang CY, Chen SH, Huang YS. Response of amoeboid and differentiating ramified microglia to glucocorticoids in postnatal rats: a lectin histochemical and ultrastructural study. Neurosci Res 2001; 40:235-44. [PMID: 11448515 DOI: 10.1016/s0168-0102(01)00231-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
After glucocorticoid injection(s), the number of amoeboid microglial cells (AMC) in the corpus callosum labelled by lectin was markedly reduced when compared with the corresponding control rats. In rats killed at the age of 7 days, all the labeled cells differentiated to become ramified microglia. Ultrastructurally, the AMC in glucocorticoid-injected rats were extremely vacuolated and showed increased lipid droplets. Furthermore, the cells displayed varied lectin labelling patterns especially at both the trans saccules of the Golgi apparatus and lysosomes. In differentiating ramified microglia, massive cellular debris and lectin-stained vesicles or vacuoles were observed; some of the latter appeared to fuse with the plasma membrane. The most striking feature after glucocorticoid (GCC) treatment was the complete diminution of lectin labelling at the Golgi saccules in some differentiating ramified microglia. The present results have demonstrated different effects of glucocorticoids on AMC and differentiating ramified microglia. The differential response of AMC and differentiating ramified microglia to the immunosuppressive drugs may be attributed to the fact that these cells in the postnatal brains subserve different functions or that they are at different differentiation stages. In other words, the sensitivity of microglial cells to the immunosuppressive drugs is dependent upon the stage of cell maturation/differentiation.
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Affiliation(s)
- C H Wu
- Department and Institute of Biology and Anatomy, National Defense Medical Center, 161, Sec. 6, Min-Chuan E. Rd., Taipei 114, Taiwan, ROC.
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17
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Abstract
The development of the olfactory bulb, the primary central relay of the olfactory system, is characterized by a striking susceptibility to alterations in the amount of afferent input. For example, blocking airflow through one half of the nasal cavity during early life results in a number of dramatic changes in the bulb, including increased cell death. Previous studies reveal high levels of microglia in the olfactory bulb. Microglia function as phagocytes, aid in synaptogenesis, and produce important trophic and cytotoxic factors. In response to a number of tissue perturbations, microglia undergo an activation process that includes, among other changes, the up-regulation of complement receptor 3. Interestingly, a previous study reported that naris closure had no effect on microglia in the bulb; however, the research did not distinguish the functional activation state of microglia. We further examined the role of microglia in the normally developing and olfactory-deprived rat bulb using immunohistochemical detection of complement receptor 3 as a measure of microglial activation. Expression of the receptor in the bulb is relatively high during postnatal development, in particular when compared to levels in cortical regions caudal to the olfactory bulb. In addition, naris closure performed on the day after birth (but not after the first postnatal month) increases levels of the receptor in an age and laminar-dependent fashion. The presence of an inducible pool of activated microglia in the olfactory bulb may be important for normal development and contribute to the plethora of changes seen after early olfactory deprivation.
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Affiliation(s)
- B K Fiske
- Neuroscience Program and Department of Psychology, University of Virginia, Charlottesville, VA 22903, USA
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Marín-Teva JL, Calvente R, Cuadros MA, Almendros A, Navascués J. Circumferential migration of ameboid microglia in the margin of the developing quail retina. Glia 1999; 27:226-38. [PMID: 10457369 DOI: 10.1002/(sici)1098-1136(199909)27:3<226::aid-glia4>3.0.co;2-t] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Central-to-peripheral migration of QH1-positive microglial precursors occurs in the vitrealmost part of the developing quail retina. This study shows that some QH1-positive ameboid cells with morphological features of migrating cells are already present in the margin of the retina before microglial precursors migrating centrally to peripherally arrive in this zone. Because the earlier cells are oriented parallel to the ora serrata, we deduce that some microglial cells migrate circumferentially in the margin of the retina, whereas other microglial precursors migrate from central to peripheral zones. Microglial cells that migrate circumferentially are first seen on embryonic day 6 (E6) and advance in a temporal-to-dorsal-to-nasal direction from the temporoventral quadrant of the retina. When cells migrating centrally to peripherally reach the retinal margin, they meet those migrating circumferentially. From E6 on, some QH1-positive dendritic cells in the ciliary body bear processes that penetrate the retina, where they are oriented circumferentially. These observations suggest that microglial cells that migrate circumferentially in the retinal margin share a common origin with dendritic cells of the ciliary body. Therefore, microglial cells of the quail retina appear to make up a heterogeneous population, with some cells originating from the pecten/optic nerve head area and others from the ciliary body.
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Affiliation(s)
- J L Marín-Teva
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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