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Green TRF, Rowe RK. Quantifying microglial morphology: an insight into function. Clin Exp Immunol 2024; 216:221-229. [PMID: 38456795 PMCID: PMC11097915 DOI: 10.1093/cei/uxae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/17/2024] [Accepted: 03/06/2024] [Indexed: 03/09/2024] Open
Abstract
Microglia are specialized immune cells unique to the central nervous system (CNS). Microglia have a highly plastic morphology that changes rapidly in response to injury or infection. Qualitative and quantitative measurements of ever-changing microglial morphology are considered a cornerstone of many microglia-centric research studies. The distinctive morphological variations seen in microglia are a useful marker of inflammation and severity of tissue damage. Although a wide array of damage-associated microglial morphologies has been documented, the exact functions of these distinct morphologies are not fully understood. In this review, we discuss how microglia morphology is not synonymous with microglia function, however, morphological outcomes can be used to make inferences about microglial function. For a comprehensive examination of the reactive status of a microglial cell, both histological and genetic approaches should be combined. However, the importance of quality immunohistochemistry-based analyses should not be overlooked as they can succinctly answer many research questions.
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Affiliation(s)
- Tabitha R F Green
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
| | - Rachel K Rowe
- Department of Integrative Physiology, The University of Colorado Boulder, Boulder, CO, USA
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2
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Martín JCM, Sánchez LF, Piñero DP, Navarro NC. Immunohistochemical, functional, and anatomical evaluation of patients with idiopathic epiretinal membrane. Graefes Arch Clin Exp Ophthalmol 2024; 262:1443-1453. [PMID: 38197992 PMCID: PMC11031491 DOI: 10.1007/s00417-023-06366-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/21/2023] [Accepted: 12/27/2023] [Indexed: 01/11/2024] Open
Abstract
PURPOSE The main purpose of this study was to perform an immunohistochemical, functional, and anatomical evaluation of patients with idiopathic epiretinal membrane (ERM). METHODS Twenty-four specimens of idiopathic ERM from 24 consecutive patients who underwent 23 G pars plana vitrectomy for ERM and internal limiting membrane (ILM) peeling at the San Juan University Hospital in Alicante (Spain) in 2019 were analyzed. All patients underwent a complete ophthalmological examination including measurement of best corrected visual acuity (BCVA) and macular analysis by spectral-domain optical coherence tomography (SD-OCT) at the time of diagnosis and 3 months after surgery. Specific glial fibrillar acid protein antibodies (GFAP) and S100 calcium-binding protein β (S100β) immunostaining markers were used to identify the macroglial component of the ERM, Müller cells, and astrocytes. Ionized calcium-binding adapter molecule 1 protein (Iba1) antibodies were used as specific markers for inflammatory cells, such as microglia and macrophages. RESULTS Mean preoperative BCVA measured with Snellen chart was 0.3 and 0.6 preoperatively and at 3 months after surgery, respectively. SD-OCT identified 15 patients (62.5%) with a disruption of the outer retinal hyperreflective bands. The immunohistochemical study showed the presence of Müller cells in almost all cases (91.6%), as well of abundant microglia and macrophages. Microglia and macrophages were more frequently present in earlier stages of ERM. Microglia were present in ERM independently of the outer retinal hyperreflective bands integrity as measured by SD-OCT. A greater presence of macrophages was found in those ERMs with no outer retinal hyperreflective band disruption. CONCLUSIONS Müller cells seem to be the most frequent cell group in ERMs, with also presence of microglia cells and macrophages. Astrocytes were more frequently found in early stages of ERMs. Microglia and macrophages were most frequent in ERMs with early stage (1, 2, or 3) than in advanced stages (4).
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Affiliation(s)
- Julio Cesar Molina Martín
- Department of Ophthalmology, San Juan University Hospital, N-332, S/NSant Joan d'Alacant, 03550, Alicante, Spain.
| | - Laura Fernández Sánchez
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Crta San Vicente del Raspeig S/NSan Vicente del Raspeig, 03690, Alicante, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Crta San Vicente del Raspeig S/NSan Vicente del Raspeig, 03690, Alicante, Spain.
| | - Nicolás Cuenca Navarro
- Department of Physiology, Genetic and Microbiology, University of Alicante, San Vicente del Raspeig, Alicante, Spain
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3
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Dieckmann BW, Paguaga ME, McCollum GW, Penn JS, Uddin MDI. Role of NLRP3 Inflammasomes in Monocyte and Microglial Recruitments in Choroidal Neovascularization. Immunohorizons 2024; 8:363-370. [PMID: 38775688 PMCID: PMC11150128 DOI: 10.4049/immunohorizons.2400025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 04/29/2024] [Indexed: 05/30/2024] Open
Abstract
Although the pathogenesis of choroidal neovascularization (CNV) is largely unknown in age-related macular degeneration (AMD), inflammasomes may contribute to CNV development and progression. To understand the role NLRP3 inflammasomes in CNV, we used Ccr2RFPCx3cr1GFP dual-reporter mice and immunostaining techniques to confirm localization of NLRP3 inflammasomes in the laser-induced CNV (LCNV) lesions. Confocal microscopy was used to image and quantify LCNV volumes. MCC950 was used as NLRP3 inhibitor. ELISA and quantitative RT-PCR were used to confirm the activation of NLRP3 by monitoring the expression of IL-1β protein and mRNA in choroidal tissues from LCNV mice. In addition, NLRP3 (-/-) LCNV mice were used to investigate whether NLRP3 inflammasomes contribute to the development of LCNV lesions. We observed that red fluorescent protein (RFP)-positive monocyte-derived macrophages and GFP-positive microglia-derived macrophages, in addition to other cell types, were localized in LCNV lesions at day 7 post-laser injury. In addition, NLRP3 inflammasomes are associated with LCNV lesions. Inhibition of NLRP3 inflammasomes, using MCC950, caused an increased Ccr2RFP-positive macrophages, Cx3cr1GFP-positive microglia, and other cells, resulting in an increase in total lesion size. NLRP3 (-/-) LCNV mice showed significantly increased lesion size compared with age-matched controls. Inhibition of NLRP3 resulted in decreased IL-1β mRNA and protein expression in the choroidal tissues, suggesting that increased lesion size may not be directly related to IL-1β.
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Affiliation(s)
- Blake W. Dieckmann
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - Marcell E. Paguaga
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - Gary W. McCollum
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - John S. Penn
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
| | - MD Imam Uddin
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN
- Department of Biomedical Engineering, Vanderbilt University School of Engineering, Nashville, TN
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4
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Gumusoglu SB, Kiel MD, Gugel A, Schickling BM, Weaver KR, Lauffer MC, Sullivan HR, Coulter KJ, Blaine BM, Kamal M, Zhang Y, Devor EJ, Santillan DA, Gantz SC, Santillan MK. Anti-angiogenic mechanisms and serotonergic dysfunction in the Rgs2 knockout model for the study of psycho-obstetric risk. Neuropsychopharmacology 2024; 49:864-875. [PMID: 37848733 PMCID: PMC10948883 DOI: 10.1038/s41386-023-01749-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/19/2023]
Abstract
Psychiatric and obstetric diseases are growing threats to public health and share high rates of co-morbidity. G protein-coupled receptor signaling (e.g., vasopressin, serotonin) may be a convergent psycho-obstetric risk mechanism. Regulator of G Protein Signaling 2 (RGS2) mutations increase risk for both the gestational disease preeclampsia and for depression. We previously found preeclampsia-like, anti-angiogenic obstetric phenotypes with reduced placental Rgs2 expression in mice. Here, we extend this to test whether conserved cerebrovascular and serotonergic mechanisms are also associated with risk for neurobiological phenotypes in the Rgs2 KO mouse. Rgs2 KO exhibited anxiety-, depression-, and hedonic-like behaviors. Cortical vascular density and vessel length decreased in Rgs2 KO; cortical and white matter thickness and cell densities were unchanged. In Rgs2 KO, serotonergic gene expression was sex-specifically changed (e.g., cortical Htr2a, Maoa increased in females but all serotonin targets unchanged or decreased in males); redox-related expression increased in paraventricular nucleus and aorta; and angiogenic gene expression was changed in male but not female cortex. Whole-cell recordings from dorsal raphe serotonin neurons revealed altered 5-HT1A receptor-dependent inhibitory postsynaptic currents (5-HT1A-IPSCs) in female but not male KO neurons. Additionally, serotonin transporter blockade by the SSRI sertraline increased the amplitude and time-to-peak of 5-HT1A-IPSCs in KO neurons to a greater extent than in WT neurons in females only. These results demonstrate behavioral, cerebrovascular, and sertraline hypersensitivity phenotypes in Rgs2 KOs, some of which are sex-specific. Disruptions may be driven by vascular and cell stress mechanisms linking the shared pathogenesis of psychiatric and obstetric disease to reveal future targets.
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Affiliation(s)
- Serena B Gumusoglu
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
| | - Michaela D Kiel
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Aleigha Gugel
- Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Brandon M Schickling
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Kaylee R Weaver
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Marisol C Lauffer
- Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
- Neural Circuits and Behavior Core, Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
| | - Hannah R Sullivan
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Kaylie J Coulter
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Brianna M Blaine
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Mushroor Kamal
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Yuping Zhang
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Eric J Devor
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Donna A Santillan
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Stephanie C Gantz
- Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, USA
| | - Mark K Santillan
- Department of Obstetrics and Gynecology, Carver College of Medicine, University of Iowa, Iowa City, USA.
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5
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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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6
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Badawi AH, Mohamad NA, Stanslas J, Kirby BP, Neela VK, Ramasamy R, Basri H. In Vitro Blood-Brain Barrier Models for Neuroinfectious Diseases: A Narrative Review. Curr Neuropharmacol 2024; 22:1344-1373. [PMID: 38073104 PMCID: PMC11092920 DOI: 10.2174/1570159x22666231207114346] [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: 09/12/2022] [Revised: 11/04/2022] [Accepted: 11/25/2022] [Indexed: 05/16/2024] Open
Abstract
The blood-brain barrier (BBB) is a complex, dynamic, and adaptable barrier between the peripheral blood system and the central nervous system. While this barrier protects the brain and spinal cord from inflammation and infection, it prevents most drugs from reaching the brain tissue. With the expanding interest in the pathophysiology of BBB, the development of in vitro BBB models has dramatically evolved. However, due to the lack of a standard model, a range of experimental protocols, BBB-phenotype markers, and permeability flux markers was utilized to construct in vitro BBB models. Several neuroinfectious diseases are associated with BBB dysfunction. To conduct neuroinfectious disease research effectively, there stems a need to design representative in vitro human BBB models that mimic the BBB's functional and molecular properties. The highest necessity is for an in vitro standardised BBB model that accurately represents all the complexities of an intact brain barrier. Thus, this in-depth review aims to describe the optimization and validation parameters for building BBB models and to discuss previous research on neuroinfectious diseases that have utilized in vitro BBB models. The findings in this review may serve as a basis for more efficient optimisation, validation, and maintenance of a structurally- and functionally intact BBB model, particularly for future studies on neuroinfectious diseases.
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Affiliation(s)
- Ahmad Hussein Badawi
- Department of Neurology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Nur Afiqah Mohamad
- Department of Neurology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
- Centre for Foundation Studies, Lincoln University College, 47301, Petaling Jaya, Selangor, Malaysia
| | - Johnson Stanslas
- Department of Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Brian Patrick Kirby
- School of Pharmacy and Biomolecular Sciences, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Vasantha Kumari Neela
- Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Rajesh Ramasamy
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Hamidon Basri
- Department of Neurology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
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7
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Rezaie P, Hanisch UK. History of Microglia. ADVANCES IN NEUROBIOLOGY 2024; 37:15-37. [PMID: 39207684 DOI: 10.1007/978-3-031-55529-9_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The term 'microglia' was first introduced into the scientific literature a century ago. The various eras of microglial research have been defined not only by the number of reports subsequently generated but, more critically, also by the concepts that have shaped our present-day views and understanding of microglia. Key methods, technologies, and models, as well as seminal discoveries made possible through their deployment have enabled breakthroughs, and now pave the way for lines of investigation that could not have been anticipated even a decade ago. Advances in our understanding of the microglial origin, forms, and functions have relied fundamentally on parallel developments in immunology. As the 'neuro-immune' cells of the brain, microglia are now under the spotlight in various disciplines. This chapter surveys the gradual processes and precipitous events that helped form ideas concerning the developmental origin of microglia and their roles in health and disease. It first covers the dawning phase during which the early pioneers of microglial research discovered cellular entities and already assigned functions to them. Following a recess period, the 1960s brought about a renaissance of active interest, with the development of tools and models-and fundamental notions on microglial contributions to central nervous system (CNS) pathologies. These seminal efforts laid the foundation for the awakening of a sweeping research era beginning in the 1980s and spurred on by a blast of immunological discoveries. Finally, this chapter stresses the advancements in molecular, genetic, and imaging approaches to the study of microglia with the turn of the millennium, enabling insights into virtually all facets of microglial physiology. Moving forward, it is clear that the future holds substantial promise for further discoveries. The next epoch in the history of microglial research has just begun.
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Affiliation(s)
- Payam Rezaie
- School of Life, Health & Chemical Sciences, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Milton Keynes, UK.
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8
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Harry GJ. Microglia Colonization Associated with Angiogenesis and Neural Cell Development. ADVANCES IN NEUROBIOLOGY 2024; 37:163-178. [PMID: 39207692 DOI: 10.1007/978-3-031-55529-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The temporal and spatial pattern of microglia colonization of the nervous system implies a role in early stages of organ development including cell proliferation, differentiation, and neurovascularization. As microglia colonize and establish within the developing nervous system, they assume a neural-specific identity and contribute to key developmental events. Their association around blood vessels implicates them in development of the vascular system or vice versa. A similar association has been reported for neural cell proliferation and associated phenotypic shifts and for cell fate differentiation to neuronal or glial phenotypes. These processes are accomplished by phagocytic activities, cell-cell contact relationships, and secretion of various factors. This chapter will present data currently available from studies evaluating the dynamic and interactive nature of these processes throughout the progression of nervous system development.
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Affiliation(s)
- G Jean Harry
- Mechanistic Toxicology Branch, Division of Translational Toxicology, National Institute Environmental Health Sciences, Research Triangle Park, NC, USA.
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9
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Olmedillas M, Brawek B, Li K, Richter C, Garaschuk O. Plaque vicinity as a hotspot of microglial turnover in a mouse model of Alzheimer's disease. Glia 2023; 71:2884-2901. [PMID: 37596829 DOI: 10.1002/glia.24458] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 07/25/2023] [Accepted: 08/04/2023] [Indexed: 08/20/2023]
Abstract
Microglia, the major immune cells of the brain, are functionally heterogeneous but in vivo functional properties of these cells are rarely studied at single-cell resolution. By using microRNA-9 regulated viral vectors for multicolor labeling and longitudinal in vivo monitoring of individual microglia, we followed their fate in the cortex of healthy adult mice and at the onset of amyloidosis in a mouse model of Alzheimer's disease. In wild-type mice, microglia were rather mobile (16% of the cells migrated at least once in 10-20 days) but had a low turnover as documented by low division and death rates. Half of the migratory events were tightly associated with blood vessels. Surprisingly, basic migration properties of microglia (i.e., fraction of migrating cells, saltatory migration pattern, speed of migration, translocation distance, and strong association with blood vessels) were preserved in amyloid-depositing brains, despite amyloid plaques becoming the major destination of migration. Besides, amyloid deposition significantly increased microglial division and death rates. Moreover, the plaque vicinity became a hotspot of microglial turnover, harboring 33% of all migration, 70% of death and 54% of division events.
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Affiliation(s)
- Maria Olmedillas
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Kaizhen Li
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Cris Richter
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
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10
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Dieckmann BW, Paguaga ME, McCollum GW, Penn JS, Uddin I. Role of NLRP3 inflammasomes in monocyte and microglial recruitments in choroidal neovascularization. RESEARCH SQUARE 2023:rs.3.rs-3318233. [PMID: 37720026 PMCID: PMC10503854 DOI: 10.21203/rs.3.rs-3318233/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Though the pathogenesis of choroidal neovascularization (CNV) is largely unknown in age-related macular degeneration (AMD), inflammasomes may contribute to CNV development and progression. To understand the role NLRP3 inflammasomes in CNV, we used Ccr2RFPCx3cr1GFP dual-reporter mice to characterize migration of Ccr2RFP positive monocytes and Cx3cr1GFP positive microglial cells into CNV lesions after laser-induced rupture of Bruch's membrane. MCC950 was used as NLRP3 inhibitor. Immunostaining was used to confirm localization of NLRP3 inflammasomes in the LCNV lesions. Confocal microscopy was used to image and quantify LCNV volumes. ELISA and qRT-PCR were used to confirm the activation of NLRP3 by monitoring the expression of IL-1β protein and mRNA in choroidal tissues from LCNV mice. In addition, NLRP3 (-/-) LCNV mice were used to investigate whether NLRP3 inflammasomes contribute to the development of LCNV lesions. We observed that RFP positive monocyte-derived macrophages and GFP positive microglia-derived macrophages, in addition to other cell types, were localized in LCNV lesions at day 7 post-laser injury. In addition, NLRP3 inflammasomes are associated with LCNV lesions. Inhibition of NLRP3 inflammasomes, using MCC950, caused an increased Ccr2RFP positive macrophages, Cx3cr1GFP positive microglia, and other cells resulting in an increase in total lesion size. NLRP3 (-/-) LCNV mice, showed significantly increased lesion size compared to age-matched controls. Inhibition of NLRP3, resulted in decreased IL-1β mRNA and protein expression in the choroidal tissues, suggesting that increased lesion size may not be directly related to IL-1β.
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Morris GP, Foster CG, Courtney J, Collins JM, Cashion JM, Brown LS, Howells DW, DeLuca GC, Canty AJ, King AE, Ziebell JM, Sutherland BA. Microglia directly associate with pericytes in the central nervous system. Glia 2023; 71:1847-1869. [PMID: 36994950 PMCID: PMC10952742 DOI: 10.1002/glia.24371] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 03/31/2023]
Abstract
Cerebral blood flow (CBF) is important for the maintenance of brain function and its dysregulation has been implicated in Alzheimer's disease (AD). Microglia associations with capillaries suggest they may play a role in the regulation of CBF or the blood-brain-barrier (BBB). We explored the relationship between microglia and pericytes, a vessel-resident cell type that has a major role in the control of CBF and maintenance of the BBB, discovering a spatially distinct subset of microglia that closely associate with pericytes. We termed these pericyte-associated microglia (PEM). PEM are present throughout the brain and spinal cord in NG2DsRed × CX3 CR1+/GFP mice, and in the human frontal cortex. Using in vivo two-photon microscopy, we found microglia residing adjacent to pericytes at all levels of the capillary tree and found they can maintain their position for at least 28 days. PEM can associate with pericytes lacking astroglial endfeet coverage and capillary vessel width is increased beneath pericytes with or without an associated PEM, but capillary width decreases if a pericyte loses a PEM. Deletion of the microglia fractalkine receptor (CX3 CR1) did not disrupt the association between pericytes and PEM. Finally, we found the proportion of microglia that are PEM declines in the superior frontal gyrus in AD. In summary, we identify microglia that specifically associate with pericytes and find these are reduced in number in AD, which may be a novel mechanism contributing to vascular dysfunction in neurodegenerative diseases.
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Affiliation(s)
- Gary P. Morris
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Catherine G. Foster
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jo‐Maree Courtney
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jessica M. Collins
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jake M. Cashion
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Lachlan S. Brown
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - David W. Howells
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Gabriele C. DeLuca
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Alison J. Canty
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
- Global Brain Health InstituteTrinity CollegeDublinIreland
| | - Anna E. King
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jenna M. Ziebell
- Wicking Dementia Research and Education Centre, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
| | - Brad A. Sutherland
- Tasmanian School of Medicine, College of Health and MedicineUniversity of TasmaniaHobartTasmaniaAustralia
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12
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Boghozian R, Sharma S, Narayana K, Cheema M, Brown CE. Sex and interferon gamma signaling regulate microglia migration in the adult mouse cortex in vivo. Proc Natl Acad Sci U S A 2023; 120:e2302892120. [PMID: 37428916 PMCID: PMC10629543 DOI: 10.1073/pnas.2302892120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 06/02/2023] [Indexed: 07/12/2023] Open
Abstract
Although microglia possess the unique ability to migrate, whether mobility is evident in all microglia, is sex dependent, and what molecular mechanisms drive this, is not well understood in the adult brain. Using longitudinal in vivo two-photon imaging of sparsely labeled microglia, we find a relatively small population of microglia (~5%) are mobile under normal conditions. Following injury (microbleed), the fraction of mobile microglia increased in a sex-dependent manner, with male microglia migrating significantly greater distances toward the microbleed relative to their female counterparts. To understand the signaling pathways involved, we interrogated the role of interferon gamma (IFNγ). Our data show that in male mice, stimulating microglia with IFNγ promotes migration whereas inhibiting IFNγ receptor 1 signaling inhibits them. By contrast, female microglia were generally unaffected by these manipulations. These findings highlight the diversity of microglia migratory responses to injury, its dependence on sex and the signaling mechanisms that modulate this behavior.
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Affiliation(s)
- Roobina Boghozian
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Kamal Narayana
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Manjinder Cheema
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Craig E. Brown
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, BCV6T 2A1, Canada
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13
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Iadecola C, Smith EE, Anrather J, Gu C, Mishra A, Misra S, Perez-Pinzon MA, Shih AY, Sorond FA, van Veluw SJ, Wellington CL. The Neurovasculome: Key Roles in Brain Health and Cognitive Impairment: A Scientific Statement From the American Heart Association/American Stroke Association. Stroke 2023; 54:e251-e271. [PMID: 37009740 PMCID: PMC10228567 DOI: 10.1161/str.0000000000000431] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
BACKGROUND Preservation of brain health has emerged as a leading public health priority for the aging world population. Advances in neurovascular biology have revealed an intricate relationship among brain cells, meninges, and the hematic and lymphatic vasculature (the neurovasculome) that is highly relevant to the maintenance of cognitive function. In this scientific statement, a multidisciplinary team of experts examines these advances, assesses their relevance to brain health and disease, identifies knowledge gaps, and provides future directions. METHODS Authors with relevant expertise were selected in accordance with the American Heart Association conflict-of-interest management policy. They were assigned topics pertaining to their areas of expertise, reviewed the literature, and summarized the available data. RESULTS The neurovasculome, composed of extracranial, intracranial, and meningeal vessels, as well as lymphatics and associated cells, subserves critical homeostatic functions vital for brain health. These include delivering O2 and nutrients through blood flow and regulating immune trafficking, as well as clearing pathogenic proteins through perivascular spaces and dural lymphatics. Single-cell omics technologies have unveiled an unprecedented molecular heterogeneity in the cellular components of the neurovasculome and have identified novel reciprocal interactions with brain cells. The evidence suggests a previously unappreciated diversity of the pathogenic mechanisms by which disruption of the neurovasculome contributes to cognitive dysfunction in neurovascular and neurodegenerative diseases, providing new opportunities for the prevention, recognition, and treatment of these conditions. CONCLUSIONS These advances shed new light on the symbiotic relationship between the brain and its vessels and promise to provide new diagnostic and therapeutic approaches for brain disorders associated with cognitive dysfunction.
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14
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Gullotta GS, Costantino G, Sortino MA, Spampinato SF. Microglia and the Blood-Brain Barrier: An External Player in Acute and Chronic Neuroinflammatory Conditions. Int J Mol Sci 2023; 24:ijms24119144. [PMID: 37298096 DOI: 10.3390/ijms24119144] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Microglia are the resident immune cells of the central nervous system that guarantee immune surveillance and exert also a modulating role on neuronal synaptic development and function. Upon injury, microglia get activated and modify their morphology acquiring an ameboid phenotype and pro- or anti-inflammatory features. The active role of microglia in blood-brain barrier (BBB) function and their interaction with different cellular components of the BBB-endothelial cells, astrocytes and pericytes-are described. Here, we report the specific crosstalk of microglia with all the BBB cell types focusing in particular on the involvement of microglia in the modulation of BBB function in neuroinflammatory conditions that occur in conjunction with an acute event, such as a stroke, or in a slow neurodegenerative disease, such as Alzheimer's disease. The potential of microglia to exert a dual role, either protective or detrimental, depending on disease stages and environmental conditioning factors is also discussed.
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Affiliation(s)
- Giorgia Serena Gullotta
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Giuseppe Costantino
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
- Ph.D. Program in Neuroscience and Education, DISTUM, University of Foggia, 71121 Foggia, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
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15
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Flores-Montoya G, Quintero D, Chatterjea D, Uttley H, Liphart C, Tian Z, Yim E, Hu F. The C-C chemokine receptor 7: An immune molecule that modulates central nervous system function in homeostasis and disease. Brain Behav Immun Health 2023; 29:100610. [PMID: 36937649 PMCID: PMC10015173 DOI: 10.1016/j.bbih.2023.100610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 02/25/2023] [Indexed: 03/03/2023] Open
Abstract
The interaction between the central nervous system (CNS) and the peripheral immune system is key for brain function in homeostasis and disease. Recent studies have revealed that the C-C chemokine receptor 7 (CCR7) is expressed in both CNS resident cells and peripheral immune cells, and plays an important role in regulating behavior in homeostasis and neuroinflammation in disease. This review integrates studies examining the role of CCR7 in CNS resident and peripheral immune cells in homeostasis and disease, as well as the pathways of peripheral immune cell migration in and out of the brain via CCR7. A special emphasis is placed on the CCR7-dependent migration of peripheral immune cells into the recently discovered meningeal lymphatic vessels surrounding the brain and nasal lymphatics, its migration into cervical lymph nodes, and the implications that this migration might have for CNS function.
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Affiliation(s)
- Gisel Flores-Montoya
- Psychology Department, Carleton College, Northfield, MN, USA
- Corresponding author.
| | - Daniel Quintero
- Psychology Department, Carleton College, Northfield, MN, USA
| | | | - Hannah Uttley
- Psychology Department, Carleton College, Northfield, MN, USA
| | - Colin Liphart
- Psychology Department, Carleton College, Northfield, MN, USA
| | - Zichen Tian
- Psychology Department, Carleton College, Northfield, MN, USA
| | - Elliot Yim
- Psychology Department, Carleton College, Northfield, MN, USA
| | - Fengping Hu
- Psychology Department, Carleton College, Northfield, MN, USA
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16
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Chen S, Li J, Meng S, He T, Shi Z, Wang C, Wang Y, Cao H, Huang Y, Zhang Y, Gong Y, Gao Y. Microglia and macrophages in the neuro-glia-vascular unit: From identity to functions. Neurobiol Dis 2023; 179:106066. [PMID: 36889483 DOI: 10.1016/j.nbd.2023.106066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Although both are myeloid cells located surrounding cerebral vasculature, vessel-associated microglia (VAM) and perivascular macrophages (PVMs) can be distinguished by their distinct morphologies, signatures and microscopic location. As key component of neuro-glia-vascular unit (NGVU), they play prominent roles in neurovasculature development and pathological process of various central nervous system (CNS) diseases, including phagocytosis, angiogenesis, vessel damage/protection and blood flow regulation, therefore serving as potential targets for therapeutics of a broad array of CNS diseases. Herein, we will provide a comprehensive overview of heterogeneity of VAM/PVMs, highlight limitations of current understanding in this field, and discuss possible directions of future investigations.
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Affiliation(s)
- Shuning Chen
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Jiaying Li
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shan Meng
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Tingyu He
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Ziyu Shi
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Chenran Wang
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yana Wang
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Hui Cao
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yichen Huang
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yue Zhang
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Ye Gong
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China.
| | - Yanqin Gao
- Department of Critical Care Medicine of Huashan Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China.
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17
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Wang Z, Chen G. Immune regulation in neurovascular units after traumatic brain injury. Neurobiol Dis 2023; 179:106060. [PMID: 36871640 DOI: 10.1016/j.nbd.2023.106060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/19/2023] [Accepted: 02/28/2023] [Indexed: 03/07/2023] Open
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Survivors may experience movement disorders, memory loss, and cognitive deficits. However, there is a lack of understanding of the pathophysiology of TBI-mediated neuroinflammation and neurodegeneration. The immune regulation process of TBI involves changes in the peripheral and central nervous system (CNS) immunity, and intracranial blood vessels are essential communication centers. The neurovascular unit (NVU) is responsible for coupling blood flow with brain activity, and comprises endothelial cells, pericytes, astrocyte end-feet, and vast regulatory nerve terminals. A stable NVU is the basis for normal brain function. The concept of the NVU emphasizes that cell-cell interactions between different types of cells are essential for maintaining brain homeostasis. Previous studies have explored the effects of immune system changes after TBI. The NVU can help us further understand the immune regulation process. Herein, we enumerate the paradoxes of primary immune activation and chronic immunosuppression. We describe the changes in immune cells, cytokines/chemokines, and neuroinflammation after TBI. The post-immunomodulatory changes in NVU components are discussed, and research exploring immune changes in the NVU pattern is also described. Finally, we summarize immune regulation therapies and drugs after TBI. Therapies and drugs that focus on immune regulation have shown great potential for neuroprotection. These findings will help us further understand the pathological processes after TBI.
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Affiliation(s)
- Zongqi Wang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, Jiangsu Province 215006, China; Institute of Stroke Research, Soochow University, Suzhou, Jiangsu Province 215006, China
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, Jiangsu Province 215006, China; Institute of Stroke Research, Soochow University, Suzhou, Jiangsu Province 215006, China.
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18
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Knopp RC, Banks WA, Erickson MA. Physical associations of microglia and the vascular blood-brain barrier and their importance in development, health, and disease. Curr Opin Neurobiol 2022; 77:102648. [PMID: 36347075 DOI: 10.1016/j.conb.2022.102648] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022]
Abstract
Brain endothelial cells (BEC) of the vascular blood-brain barrier (BBB) interact with many different cell types in the brain, including microglia, the brain's resident immune cells. Physical associations of microglia with the BBB and the importance of these interactions in health and disease are an emerging area of study and likely involved in neuroimmune communication. In this mini-review, we consider how microglia and the BBB are intrinsically linked in the developing brain, discuss possible mechanisms that attract microglia to the vasculature in healthy physiological conditions, and examine the known microglial-vascular associated changes in systemic infection and various disease states. Our findings shed light on the complexities of microglial-vascular interactions and highlight the contributions of microglia to the functions of the neurovascular unit.
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Affiliation(s)
- Rachel C Knopp
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - William A Banks
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
| | - Michelle A Erickson
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA USA, 98108; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
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19
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Reactive Microgliosis in Sepsis-Associated and Acute Hepatic Encephalopathies: An Ultrastructural Study. Int J Mol Sci 2022; 23:ijms232214455. [PMID: 36430933 PMCID: PMC9696099 DOI: 10.3390/ijms232214455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 11/23/2022] Open
Abstract
Sepsis and acute liver failure are associated with severe endogenous intoxication. Microglia, which are the resident immune brain cells, play diverse roles in central nervous system development, surveillance, and defense, as well as contributing to neuroinflammatory reactions. In particular, microglia are fundamental to the pathophysiology of reactive toxic encephalopathies. We analyzed microglial ultrastructure, morphotypes, and phagocytosis in the sensorimotor cortex of cecal ligation and puncture (CLP) and acetaminophen-induced liver failure (AILF) Wistar rats. A CLP model induced a gradual shift of ~50% of surveillant microglia to amoeboid hypertrophic-like and gitter cell-like reactive phenotypes with active phagocytosis and frequent contacts with damaged neurons. In contrast, AILF microglia exhibited amoeboid, rod-like, and hypertrophic-like reactive morphotypes with minimal indications for efficient phagocytosis, and were mostly in contact with edematous astrocytes. Close interactions of reactive microglia with neurons, astrocytes, and blood-brain barrier components reflect an active contribution of these cells to the tissue adaptation and cellular remodeling to toxic brain damage. Partial disability of reactive microglia may affect the integrity and metabolism in all tissue compartments, leading to failure of the compensatory mechanisms in acute endogenous toxic encephalopathies.
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20
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Reciprocal Interactions between Oligodendrocyte Precursor Cells and the Neurovascular Unit in Health and Disease. Cells 2022; 11:cells11121954. [PMID: 35741083 PMCID: PMC9221698 DOI: 10.3390/cells11121954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/02/2022] [Accepted: 06/14/2022] [Indexed: 12/04/2022] Open
Abstract
Oligodendrocyte precursor cells (OPCs) are mostly known for their capability to differentiate into oligodendrocytes and myelinate axons. However, they have been observed to frequently interact with cells of the neurovascular unit during development, homeostasis, and under pathological conditions. The functional consequences of these interactions are largely unclear, but are increasingly studied. Although OPCs appear to be a rather homogenous cell population in the central nervous system (CNS), they present with an enormous potential to adapt to their microenvironment. In this review, it is summarized what is known about the various roles of OPC-vascular interactions, and the circumstances under which they have been observed.
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21
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Zhao Q, Dai W, Chen HY, Jacobs RE, Zlokovic BV, Lund BT, Montagne A, Bonnin A. Prenatal disruption of blood-brain barrier formation via cyclooxygenase activation leads to lifelong brain inflammation. Proc Natl Acad Sci U S A 2022; 119:e2113310119. [PMID: 35377817 PMCID: PMC9169666 DOI: 10.1073/pnas.2113310119] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 02/14/2022] [Indexed: 11/21/2022] Open
Abstract
Gestational maternal immune activation (MIA) in mice induces persistent brain microglial activation and a range of neuropathologies in the adult offspring. Although long-term phenotypes are well documented, how MIA in utero leads to persistent brain inflammation is not well understood. Here, we found that offspring of mothers treated with polyriboinosinic–polyribocytidylic acid [poly(I:C)] to induce MIA at gestational day 13 exhibit blood–brain barrier (BBB) dysfunction throughout life. Live MRI in utero revealed fetal BBB hyperpermeability 2 d after MIA. Decreased pericyte–endothelium coupling in cerebral blood vessels and increased microglial activation were found in fetal and 1- and 6-mo-old offspring brains. The long-lasting disruptions result from abnormal prenatal BBB formation, driven by increased proliferation of cyclooxygenase-2 (COX2; Ptgs2)-expressing microglia in fetal brain parenchyma and perivascular spaces. Targeted deletion of the Ptgs2 gene in fetal myeloid cells or treatment with the inhibitor celecoxib 24 h after immune activation prevented microglial proliferation and disruption of BBB formation and function, showing that prenatal COX2 activation is a causal pathway of MIA effects. Thus, gestational MIA disrupts fetal BBB formation, inducing persistent BBB dysfunction, which promotes microglial overactivation and behavioral alterations across the offspring life span. Taken together, the data suggest that gestational MIA disruption of BBB formation could be an etiological contributor to neuropsychiatric disorders.
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Affiliation(s)
- Qiuying Zhao
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Weiye Dai
- Master of Science, Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, CA 90089
| | - Hui Yu Chen
- Master of Medical Physiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Russell E. Jacobs
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Berislav V. Zlokovic
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Brett T. Lund
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
| | - Axel Montagne
- UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, EH16 4SB Edinburgh, United Kingdom
- Centre for Clinical Brain Sciences, Edinburgh BioQuarter, EH16 4SB Edinburgh, United Kingdom
| | - Alexandre Bonnin
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
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22
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Neurovascular Unit Alterations in the Growth-Restricted Newborn Are Improved Following Ibuprofen Treatment. Mol Neurobiol 2021; 59:1018-1040. [PMID: 34825315 DOI: 10.1007/s12035-021-02654-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/17/2021] [Indexed: 10/19/2022]
Abstract
The developing brain is particularly vulnerable to foetal growth restriction (FGR) and abnormal neurodevelopment is common in the FGR infant ranging from behavioural and learning disorders to cerebral palsy. No treatment exists to protect the FGR newborn brain. Recent evidence suggests inflammation may play a key role in the mechanism responsible for the progression of brain impairment in the FGR newborn, including disruption to the neurovascular unit (NVU). We explored whether ibuprofen, an anti-inflammatory drug, could reduce NVU disruption and brain impairment in the FGR newborn. Using a preclinical FGR piglet model, ibuprofen was orally administered for 3 days from birth. FGR brains demonstrated a proinflammatory state, with changes to glial morphology (astrocytes and microglia), and blood-brain barrier disruption, assessed by IgG and albumin leakage into the brain parenchyma and a decrease in blood vessel density. Loss of interaction between astrocytic end-feet and blood vessels was evident where plasma protein leakage was present, suggestive of structural deficits to the NVU. T-cell infiltration was also evident in the parenchyma of FGR piglet brains. Ibuprofen treatment reduced the pro-inflammatory response in FGR piglets, reducing the number of activated microglia and enhancing astrocyte interaction with blood vessels. Ibuprofen also attenuated plasma protein leakage, regained astrocytic end-feet interaction around vessels, and decreased T-cell infiltration into the FGR brain. These findings suggest postnatal administration of ibuprofen modulates the inflammatory state, allowing for stronger interaction between vasculature and astrocytic end-feet to restore NVU integrity. Modulation of the NVU improves the FGR brain microenvironment and may be key to neuroprotection.
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23
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Augusto-Oliveira M, Arrifano GP, Delage CI, Tremblay MÈ, Crespo-Lopez ME, Verkhratsky A. Plasticity of microglia. Biol Rev Camb Philos Soc 2021; 97:217-250. [PMID: 34549510 DOI: 10.1111/brv.12797] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Microglial cells are the scions of foetal macrophages which invade the neural tube early during embryogenesis. The nervous tissue environment instigates the phenotypic metamorphosis of foetal macrophages into idiosyncratic surveilling microglia, which are generally characterised by a small cell body and highly ramified motile processes that constantly scan the nervous tissue for signs of changes in homeostasis and allow microglia to perform crucial homeostatic functions. The surveilling microglial phenotype is evolutionarily conserved from early invertebrates to humans. Despite this evolutionary conservation, microglia show substantial heterogeneity in their gene and protein expression, as well as morphological appearance. These differences are age, region and context specific and reflect a high degree of plasticity underlying the life-long adaptation of microglia, supporting the exceptional adaptive capacity of the central nervous system. Microgliocytes are essential elements of cellular network formation and refinement in the developing nervous tissue. Several distinct patrolling modes of microglial processes contribute to the formation, modification, and pruning of synapses; to the support and protection of neurones through microglial-somatic junctions; and to the control of neuronal and axonal excitability by specific microglia-axonal contacts. In pathology, microglia undergo proliferation and reactive remodelling known as microgliosis, which is context dependent, yet represents an evolutionarily conserved defence response. Microgliosis results in the emergence of multiple disease and context-specific reactive states; in addition, neuropathology is associated with the appearance of specific protective or recovery microglial forms. In summary, the plasticity of microglia supports the development and functional activity of healthy nervous tissue and provides highly sophisticated defences against disease.
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Affiliation(s)
- Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Gabriela P Arrifano
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Charlotte Isabelle Delage
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, Medical Sciences Building, University of Victoria, Victoria, BC, V8P 5C2, Canada.,Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada.,Neurology and Neurosurgery Department, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.,Department of Molecular Medicine, Université Laval, Pavillon Ferdinand-Vandry, Bureau 4835, 1050 Avenue de la Médecine, Québec City, QC, G1V 0A6, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Life Sciences Center, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Maria Elena Crespo-Lopez
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, 66075-110, Belém, Brazil
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, U.K.,Achucarro Center for Neuroscience, IKERBASQUE, 48011, Bilbao, Spain.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania
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24
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Abstract
Microglia are the resident immune cells of the central nervous system. Microglial progenitors are generated in the yolk sac during the early embryonic stage. Once microglia enter the brain primordium, these cells colonize the structure through migration and proliferation during brain development. Microglia account for a minor population among the total cells that constitute the developing cortex, but they can associate with many surrounding neural lineage cells by extending their filopodia and through their broad migration capacity. Of note, microglia change their distribution in a stage-dependent manner in the developing brain: microglia are homogenously distributed in the pallium in the early and late embryonic stages, whereas these cells are transiently absent from the cortical plate (CP) from embryonic day (E) 15 to E16 and colonize the ventricular zone (VZ), subventricular zone (SVZ), and intermediate zone (IZ). Previous studies have reported that microglia positioned in the VZ/SVZ/IZ play multiple roles in neural lineage cells, such as regulating neurogenesis, cell survival and neuronal circuit formation. In addition to microglial functions in the zones in which microglia are replenished, these cells indirectly contribute to the proper maturation of post-migratory neurons by exiting the CP during the mid-embryonic stage. Overall, microglial time-dependent distributional changes are necessary to provide particular functions that are required in specific regions. This review summarizes recent advances in the understanding of microglial colonization and multifaceted functions in the developing brain, especially focusing on the embryonic stage, and discuss the molecular mechanisms underlying microglial behaviors.
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25
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Bisht K, Okojie KA, Sharma K, Lentferink DH, Sun YY, Chen HR, Uweru JO, Amancherla S, Calcuttawala Z, Campos-Salazar AB, Corliss B, Jabbour L, Benderoth J, Friestad B, Mills WA, Isakson BE, Tremblay MÈ, Kuan CY, Eyo UB. Capillary-associated microglia regulate vascular structure and function through PANX1-P2RY12 coupling in mice. Nat Commun 2021; 12:5289. [PMID: 34489419 PMCID: PMC8421455 DOI: 10.1038/s41467-021-25590-8] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022] Open
Abstract
Microglia are brain-resident immune cells with a repertoire of functions in the brain. However, the extent of their interactions with the vasculature and potential regulation of vascular physiology has been insufficiently explored. Here, we document interactions between ramified CX3CR1 + myeloid cell somata and brain capillaries. We confirm that these cells are bona fide microglia by molecular, morphological and ultrastructural approaches. Then, we give a detailed spatio-temporal characterization of these capillary-associated microglia (CAMs) comparing them with parenchymal microglia (PCMs) in their morphological activities including during microglial depletion and repopulation. Molecularly, we identify P2RY12 receptors as a regulator of CAM interactions under the control of released purines from pannexin 1 (PANX1) channels. Furthermore, microglial elimination triggered capillary dilation, blood flow increase, and impaired vasodilation that were recapitulated in P2RY12-/- and PANX1-/- mice suggesting purines released through PANX1 channels play important roles in activating microglial P2RY12 receptors to regulate neurovascular structure and function.
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Affiliation(s)
- Kanchan Bisht
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Kenneth A Okojie
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Kaushik Sharma
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Dennis H Lentferink
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Yu-Yo Sun
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Hong-Ru Chen
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Joseph O Uweru
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Saipranusha Amancherla
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Zainab Calcuttawala
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Antony Brayan Campos-Salazar
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Bruce Corliss
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Lara Jabbour
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Jordan Benderoth
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Bria Friestad
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - William A Mills
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Département de médecine moléculaire, Université Laval, Québec, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Biochemistry and Molecular Biology, Faculty of Medicine, The University of British Colombia, Vancouver, BC, Canada
| | - Chia-Yi Kuan
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA
| | - Ukpong B Eyo
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA.
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, USA.
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, USA.
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Hammel JH, Cook SR, Belanger MC, Munson JM, Pompano RR. Modeling Immunity In Vitro: Slices, Chips, and Engineered Tissues. Annu Rev Biomed Eng 2021; 23:461-491. [PMID: 33872520 PMCID: PMC8277680 DOI: 10.1146/annurev-bioeng-082420-124920] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Modeling immunity in vitro has the potential to be a powerful tool for investigating fundamental biological questions, informing therapeutics and vaccines, and providing new insight into disease progression. There are two major elements to immunity that are necessary to model: primary immune tissues and peripheral tissues with immune components. Here, we systematically review progress made along three strategies to modeling immunity: ex vivo cultures, which preserve native tissue structure; microfluidic devices, which constitute a versatile approach to providing physiologically relevant fluid flow and environmental control; and engineered tissues, which provide precise control of the 3D microenvironment and biophysical cues. While many models focus on disease modeling, more primary immune tissue models are necessary to advance the field. Moving forward, we anticipate that the expansion of patient-specific models may inform why immunity varies from patient to patient and allow for the rapid comprehension and treatment of emerging diseases, such as coronavirus disease 2019.
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Affiliation(s)
- Jennifer H Hammel
- Fralin Biomedical Research Institute and Department of Biomedical Engineering and Mechanics, Virginia Tech, Roanoke, Virginia 24016, USA;
| | - Sophie R Cook
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Maura C Belanger
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Jennifer M Munson
- Fralin Biomedical Research Institute and Department of Biomedical Engineering and Mechanics, Virginia Tech, Roanoke, Virginia 24016, USA;
| | - Rebecca R Pompano
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22904, USA;
- Carter Immunology Center and UVA Cancer Center, University of Virginia School of Medicine, Charlottesville, Virginia 22903, USA
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Casali BT, Reed-Geaghan EG. Microglial Function and Regulation during Development, Homeostasis and Alzheimer's Disease. Cells 2021; 10:957. [PMID: 33924200 PMCID: PMC8074610 DOI: 10.3390/cells10040957] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022] Open
Abstract
Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer's disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.
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Affiliation(s)
| | - Erin G. Reed-Geaghan
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA;
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Abstract
PURPOSE OF REVIEW Rapidly emerging evidence implicates an important role of gut-brain-bone marrow (BM) axis involving gut microbiota (GM), gut epithelial wall permeability, increased production of pro-inflammatory BM cells and neuroinflammation in hypertension (HTN). However, the precise sequence of events involving these organs remains to be established. Furthermore, whether an impaired gut-brain-BM axis is a cause or consequence of HTN is actively under investigation. This will be extremely important for translation of this fundamental knowledge to novel, innovative approaches for the control and management of HTN. Therefore, our objectives are to summarize the latest hypothesis, provide evidence for and against the impaired gut, BM and brain interactions in HTN and discuss perspectives and future directions. RECENT FINDINGS Hypertensive stimuli activate autonomic neural pathways resulting in increased sympathetic and decreased parasympathetic cardiovascular modulation. This directly affects the functions of cardiovascular-relevant organs to increase blood pressure. Increases in sympathetic drive to the gut and BM also trigger sequences of signaling events that ultimately contribute to altered GM, increased gut permeability, enhanced gut- and brain-targeted pro-inflammatory cells from the BM in perpetuation and establishment of HTN. SUMMARY In this review, we present the mechanisms involving the brain, gut, and BM, whose dysfunctional interactions may be critical in persistent neuroinflammation and key in the development and establishment of HTN.
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Affiliation(s)
- Jing Li
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL, USA
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Verkhratsky A, Sun D, Tanaka J. Snapshot of microglial physiological functions. Neurochem Int 2021; 144:104960. [PMID: 33460721 DOI: 10.1016/j.neuint.2021.104960] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
Microglia as a defensive arm of the nervous system emerged early in evolution. The surveilling microglia with motile and ramified processes are the main phenotype in the healthy CNS; the surveilling microglial patrol neuronal somata, dendrites, dendritic spines and axons. Increasing evidence suggests that microglia play fundamental roles in development, maturation and ageing of the brain, as well as contribute to a variety of physiological brain processes including sleep and circadian rhythm. Physiological state of microglia is tightly regulated by brain microenvironment and controlled by a sophisticated system of receptors and signalling cascades including ionotropic and metabotropic purinoceptors, pattern-recognition receptors, and receptors for chemokines and cytokines. Microglia also utilise ion channels and transporters in regulating ionic homeostasis and various aspects of microglial function. The major ion transporters expressed by microglia include Na+/H+ exchanger 1 and Na+/Ca2+ exchangers, which are involved in regulation of pHi and Ca2+ homeostasis during microglial physiological responses. Microglial cells control development, maturation and plasticity of neuronal ensembles through controlled physiological phagocytosis of synapses or synaptic fragments - processes known as synaptic pruning and trogocytosis. This special issue on "Physiological roles of microglia" is an assembly of papers written by the leading experts in this research field. We start this special issue with this snapshot of microglial physiological functions as a prelude to the indepth discussion of microglia in physiological processes in the nervous system.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Dandan Sun
- Department of Neurology and Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, PA, 15213, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, 15213, USA.
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Ehime, 791-0295, Japan.
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Seasonal adaptations of the hypothalamo-neurohypophyseal system of the dromedary camel. PLoS One 2019; 14:e0216679. [PMID: 31211771 PMCID: PMC6581255 DOI: 10.1371/journal.pone.0216679] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 04/24/2019] [Indexed: 12/12/2022] Open
Abstract
The “ship” of the Arabian and North African deserts, the one-humped dromedary camel (Camelus dromedarius) has a remarkable capacity to survive in conditions of extreme heat without needing to drink water. One of the ways that this is achieved is through the actions of the antidiuretic hormone arginine vasopressin (AVP), which is made in a specialised part of the brain called the hypothalamo-neurohypophyseal system (HNS), but exerts its effects at the level of the kidney to provoke water conservation. Interestingly, our electron microscopy studies have shown that the ultrastructure of the dromedary HNS changes according to season, suggesting that in the arid conditions of summer the HNS is in an activated state, in preparation for the likely prospect of water deprivation. Based on our dromedary genome sequence, we have carried out an RNAseq analysis of the dromedary HNS in summer and winter. Amongst the 171 transcripts found to be significantly differentially regulated (>2 fold change, p value <0.05) there is a significant over-representation of neuropeptide encoding genes, including that encoding AVP, the expression of which appeared to increase in summer. Identification of neuropeptides in the HNS and analysis of neuropeptide profiles in extracts from individual camels using mass spectrometry indicates that overall AVP peptide levels decreased in the HNS during summer compared to winter, perhaps due to increased release during periods of dehydration in the dry season.
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Smolders SMT, Kessels S, Vangansewinkel T, Rigo JM, Legendre P, Brône B. Microglia: Brain cells on the move. Prog Neurobiol 2019; 178:101612. [PMID: 30954517 DOI: 10.1016/j.pneurobio.2019.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, tremendous progress has been made in understanding the biology of microglia - i.e. the fascinating immigrated resident immune cell population of the central nervous system (CNS). Recent literature reviews have largely dealt with the plentiful functions of microglia in CNS homeostasis, development and pathology, and the influences of sex and the microbiome. In this review, the intriguing aspect of their physical plasticity during CNS development will get specific attention. Microglia move around (mobility) and reshape their processes (motility). Microglial migration into and inside the CNS is most prominent throughout development and consequently most of the data described in this review concern mobility and motility in the changing environment of the developing brain. Here, we first define microglia based on their highly specialized age- and region-dependent gene expression signature and associated functional heterogeneity. Next, we describe their origin, the migration route of immature microglial cells towards the CNS, the mechanisms underlying their invasion of the CNS, and their spatiotemporal localization and surveying behaviour inside the developing CNS. These processes are dependent on microglial mobility and motility which are determined by the microenvironment of the CNS. Therefore, we further zoom in on the changing environment during CNS development. We elaborate on the extracellular matrix and the respective integrin receptors on microglia and we discuss the purinergic and molecular signalling in microglial mobility. In the last section, we discuss the physiological and pathological functions of microglia in which mobility and motility are involved to stress the importance of microglial 'movement'.
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Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium; INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Pascal Legendre
- INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
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Sirerol-Piquer MS, Belenguer G, Morante-Redolat JM, Duart-Abadia P, Perez-Villalba A, Fariñas I. Physiological Interactions between Microglia and Neural Stem Cells in the Adult Subependymal Niche. Neuroscience 2019; 405:77-91. [PMID: 30677487 DOI: 10.1016/j.neuroscience.2019.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/07/2019] [Accepted: 01/10/2019] [Indexed: 12/31/2022]
Abstract
Microglia are the prototypical innate immune cells of the central nervous system. They constitute a unique type of tissue-resident mononuclear phagocytes which act as glial cells. Elegant experiments in the last few years have revealed the origin, extraordinary molecular diversity, and phenotypic plasticity of these cells and how their potential relates to both immune and non-immune actions in the normal and diseased brain. Microglial cells originate in the yolk sac and colonize the brain during embryogenesis, playing a role in neural development and later in adult brain function. Neurogenesis continues after birth in discrete areas of the mammalian brain sustained by the postnatal persistence of neural stem cells in specific neurogenic niches. Recent data indicate that microglial cells are distinct cellular elements of these neurogenic niches where they regulate different aspects of stem cell biology. Interestingly, microglial and neural stem cells are specified very early in fetal development and persist as self-renewing populations throughout life, suggesting potential life-long interactions between them. We aim at reviewing these interactions in one neurogenic niche, the subependymal zone.
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Affiliation(s)
- Mª Salomé Sirerol-Piquer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Germán Belenguer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - José Manuel Morante-Redolat
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Pere Duart-Abadia
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Ana Perez-Villalba
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Isabel Fariñas
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Departamento de Biología Celular, Biología Funcional y Antropología Física and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain.
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Schnieder TP, Zhou Qin ID, Trencevska-Ivanovska I, Rosoklija G, Stankov A, Pavlovski G, Mann JJ, Dwork AJ. Blood Vessels and Perivascular Phagocytes of Prefrontal White and Gray Matter in Suicide. J Neuropathol Exp Neurol 2019; 78:15-30. [PMID: 30496451 PMCID: PMC6289219 DOI: 10.1093/jnen/nly103] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Inflammatory processes may contribute to psychiatric disorders and suicide. Earlier, we reported greater densities of perivascular phagocytes in dorsal prefrontal white matter (DPFWM) in suicide than in non-suicide deaths. To distinguish between greater vascularity and greater coverage of vessels by perivascular phagocytes, and to determine whether the excess of perivascular phagocytes is derived from microglia or from non-parenchymal immune cells, we made stereological estimates of vascular surface area density (AVTOTAL) by staining for glucose transporter Glut-1, and the fraction of vascular surface area (AF) immunoreactive (IR) for CD163 (CD163 AF) in dorsal and ventral prefrontal white and gray matter. Manner of death or psychiatric diagnosis showed no association with CD163 AF in any region. Suicide was associated with a lower AVTOTAL compared with non-suicides in DPFWM (p = 0.018) but not with AVTOTAL in the 3 other regions of interest. Thus, the earlier observation of increased density of perivascular phagocytes in DPFWM after suicide cannot be attributed to infiltration by peripheral monocytes or to increased vascularity. Greater AVTOTAL ventrally than dorsally (p = 0.002) was unique to suicide and white matter.
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Affiliation(s)
- Tatiana P Schnieder
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University, New York, New York
- New York State Psychiatric Institute, New York, New York
| | - Isaiah D Zhou Qin
- Columbia University School of Professional Studies, Columbia University, New York, New York
| | | | - Gorazd Rosoklija
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University, New York, New York
- New York State Psychiatric Institute, New York, New York
- Macedonian Academy of Sciences and Arts, Skopje, R. Macedonia
| | - Aleksandar Stankov
- School of Medicine, University “Ss.Cyril and Methodius”, Skopje, R. Macedonia
| | - Goran Pavlovski
- School of Medicine, University “Ss.Cyril and Methodius”, Skopje, R. Macedonia
| | - J John Mann
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University, New York, New York
- New York State Psychiatric Institute, New York, New York
| | - Andrew J Dwork
- Division of Molecular Imaging and Neuropathology, Department of Psychiatry, Columbia University, New York, New York
- New York State Psychiatric Institute, New York, New York
- Macedonian Academy of Sciences and Arts, Skopje, R. Macedonia
- Department of Pathology and Cell Biology, Columbia University, New York, New York
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Thurgur H, Pinteaux E. Microglia in the Neurovascular Unit: Blood-Brain Barrier-microglia Interactions After Central Nervous System Disorders. Neuroscience 2018; 405:55-67. [PMID: 31007172 DOI: 10.1016/j.neuroscience.2018.06.046] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/26/2018] [Accepted: 06/27/2018] [Indexed: 12/11/2022]
Abstract
Over the past few decades, microglial cells have been regarded as the main executor of inflammation after acute and chronic central nervous system (CNS) disorders, responding rapidly to exogenous stimuli during acute trauma or infections, or signals released by cells undergoing cell death during conditions such as stroke, Alzheimer's disease (AD) and Parkinson's disease (PD). Barriers of the nervous system, and in particular the blood-brain barrier (BBB), play a key role in the normal physiological and cognitive functions of the brain. Being at the interface between the central and peripheral compartment, the BBB is regarded as a sensor of homeostasis, and any disruption within the brain or the systemic compartment triggers BBB dysfunction and neuroinflammation, both contributing to the pathogenesis of cerebrovascular disease. This involves a dynamic response mediated by all components of the neurovascular unit (NVU), and ongoing research suggests that BBB-microglia interaction is critical to dictate the microglial response to NVU injury. The present review aims to give an up-to-date account of the emerging critical role of BBB-microglia interactions during neuroinflammation, and how these could be targeted for the therapeutic treatment of major central inflammatory disease.
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Affiliation(s)
- Hannah Thurgur
- Faculty of Biology, Medicine and Health, AV Hill Building, The University of Manchester, United Kingdom
| | - Emmanuel Pinteaux
- Faculty of Biology, Medicine and Health, AV Hill Building, The University of Manchester, United Kingdom.
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Sandvig I, Augestad IL, Håberg AK, Sandvig A. Neuroplasticity in stroke recovery. The role of microglia in engaging and modifying synapses and networks. Eur J Neurosci 2018; 47:1414-1428. [PMID: 29786167 DOI: 10.1111/ejn.13959] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 02/06/2023]
Abstract
Neuroplasticity after ischaemic injury involves both spontaneous rewiring of neural networks and circuits as well as functional responses in neurogenic niches. These events involve complex interactions with activated microglia, which evolve in a dynamic manner over time. Although the exact mechanisms underlying these interactions remain poorly understood, increasing experimental evidence suggests a determining role of pro- and anti-inflammatory microglial activation profiles in shaping both synaptogenesis and neurogenesis. While the inflammatory response of microglia was thought to be detrimental, a more complex profile of the role of microglia in tissue remodelling is emerging. Experimental evidence suggests that microglia in response to injury can rapidly modify neuronal activity and modulate synaptic function, as well as be beneficial for the proliferation and integration of neural progenitor cells (NPCs) from endogenous neurogenic niches into functional networks thereby supporting stroke recovery. The manner in which microglia contribute towards sculpting neural synapses and networks, both in terms of activity-dependent and homeostatic plasticity, suggests that microglia-mediated pro- and/or anti-inflammatory activity may significantly contribute towards spontaneous neuronal plasticity after ischaemic lesions. In this review, we first introduce some of the key cellular and molecular mechanisms underlying neuroplasticity in stroke and then proceed to discuss the crosstalk between microglia and endogenous neuroplasticity in response to brain ischaemia with special focus on the engagement of synapses and neural networks and their implications for grey matter integrity and function in stroke repair.
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Affiliation(s)
- Ioanna Sandvig
- Faculty of Medicine and Health Sciences, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ingrid Lovise Augestad
- Faculty of Medicine and Health Sciences, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Asta Kristine Håberg
- Faculty of Medicine and Health Sciences, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Radiology and Nuclear Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Axel Sandvig
- Faculty of Medicine and Health Sciences, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Neurology, St Olav's Hospital, Trondheim University Hospital, Trondheim, Norway.,Department of Pharmacology and Clinical Neurosciences, Division of Neuro, Head and Neck, Umeå University Hospital, Umeå, Sweden
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Zhao X, Eyo UB, Murguan M, Wu LJ. Microglial interactions with the neurovascular system in physiology and pathology. Dev Neurobiol 2018; 78:604-617. [PMID: 29318762 PMCID: PMC5980686 DOI: 10.1002/dneu.22576] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/01/2018] [Accepted: 01/06/2018] [Indexed: 01/11/2023]
Abstract
Microglia as immune cells of the central nervous system (CNS) play significant roles not only in pathology but also in physiology, such as shaping of the CNS during development and its proper maintenance in maturity. Emerging research is showing a close association between microglia and the neurovasculature that is critical for brain energy supply. In this review, we summarize the current literature on microglial interaction with the vascular system in the normal and diseased brain. First, we highlight data that indicate interesting potential involvement of microglia in developmental angiogenesis. Then we discuss the evidence for microglial participation with the vasculature in neuropathologies from brain tumors to acute injuries such as ischemic stroke to chronic neurodegenerative conditions. We conclude by suggesting future areas of research to advance the field in light of current technical progress and outstanding questions. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 604-617, 2018.
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Affiliation(s)
- Xiaoliang Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
| | - Ukpong B. Eyo
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Madhuvika Murguan
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
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37
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Abstract
SUMMARYThis review of available longitudinal structural imaging and immunological findings in first-onset schizophrenia, bipolar disorder, attention-deficit hyperactivity disorder (ADHD) and autism suggests that different patterns of synaptic pruning lead to various phenotypes. Proposals for future research strategies to try to replicate these findings are suggested, potential biomarkers to assist in diagnosis and determining the optimum duration of maintenance treatment are considered and ideas of potential immunotherapy augmentation are outlined.LEARNING OBJECTIVES•Understand the immunological basis of synaptic pruning•Comprehend the available research on longitudinal brain imaging•Be aware of future immunological therapeutic strategies in psychosis, ADHD and autismDECLARATION OF INTERESTNone.
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Smolders SMT, Swinnen N, Kessels S, Arnauts K, Smolders S, Le Bras B, Rigo JM, Legendre P, Brône B. Age-specific function of α5β1 integrin in microglial migration during early colonization of the developing mouse cortex. Glia 2017; 65:1072-1088. [PMID: 28417486 DOI: 10.1002/glia.23145] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/10/2017] [Accepted: 03/14/2017] [Indexed: 12/31/2022]
Abstract
Microglia, the immune cells of the central nervous system, take part in brain development and homeostasis. They derive from primitive myeloid progenitors that originate in the yolk sac and colonize the brain mainly through intensive migration. During development, microglial migration speed declines which suggests that their interaction with the microenvironment changes. However, the matrix-cell interactions allowing dispersion within the parenchyma are unknown. Therefore, we aimed to better characterize the migration behavior and to assess the role of matrix-integrin interactions during microglial migration in the embryonic brain ex vivo. We focused on microglia-fibronectin interactions mediated through the fibronectin receptor α5β1 integrin because in vitro work indirectly suggested a role for this ligand-receptor pair. Using 2-photon time-lapse microscopy on acute ex vivo embryonic brain slices, we found that migration occurs in a saltatory pattern and is developmentally regulated. Most importantly, there is an age-specific function of the α5β1 integrin during microglial cortex colonization. At embryonic day (E) 13.5, α5β1 facilitates migration while from E15.5, it inhibits migration. These results indicate a developmentally regulated function of α5β1 integrin in microglial migration during colonization of the embryonic brain.
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Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium.,INSERM, UMR_S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Silke Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium.,Laboratory of Neuronal Differentiation, VIB Center for the Biology of Disease, Leuven and Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Barbara Le Bras
- INSERM, UMR_S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | - Pascal Legendre
- INSERM, UMR_S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
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Multitasking Microglia and Alzheimer's Disease: Diversity, Tools and Therapeutic Targets. J Mol Neurosci 2016; 60:390-404. [PMID: 27660215 DOI: 10.1007/s12031-016-0825-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 08/17/2016] [Indexed: 01/08/2023]
Abstract
Given the importance of microglia to inflammatory, phagocytic and synaptic modulatory processes, their function is vital in physiological and pathological brain. The impairment of microglia in Alzheimer's disease has been demonstrated on genetic, epigenetic, transcriptional and functional levels using unbiased systems level approaches. Recent studies have highlighted the immense phenotypic diversity of microglia, including the ability to adopt distinct and dynamic phenotypes in ageing and disease. We review the origins and functions of healthy microglia and the established and emerging models and techniques available for their study. Furthermore, we highlight recent advances on the role, heterogeneity and dysfunction of microglia in Alzheimer's disease and discuss the potential for therapeutic interventions targeting microglia. Microglia-selective molecular fingerprints will guide detailed functional analysis of microglial subsets and may aid in the development of therapies specifically targeting microglia.
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Eyo UB, Miner SA, Weiner JA, Dailey ME. Developmental changes in microglial mobilization are independent of apoptosis in the neonatal mouse hippocampus. Brain Behav Immun 2016; 55:49-59. [PMID: 26576723 PMCID: PMC4864211 DOI: 10.1016/j.bbi.2015.11.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 10/09/2015] [Accepted: 11/09/2015] [Indexed: 12/31/2022] Open
Abstract
During CNS development, microglia transform from highly mobile amoeboid-like cells to primitive ramified forms and, finally, to highly branched but relatively stationary cells in maturity. The factors that control developmental changes in microglia are largely unknown. Because microglia detect and clear apoptotic cells, developmental changes in microglia may be controlled by neuronal apoptosis. Here, we assessed the extent to which microglial cell density, morphology, motility, and migration are regulated by developmental apoptosis, focusing on the first postnatal week in the mouse hippocampus when the density of apoptotic bodies peaks at postnatal day 4 and declines sharply thereafter. Analysis of microglial form and distribution in situ over the first postnatal week showed that, although there was little change in the number of primary microglial branches, microglial cell density increased significantly, and microglia were often seen near or engulfing apoptotic bodies. Time-lapse imaging in hippocampal slices harvested at different times over the first postnatal week showed differences in microglial motility and migration that correlated with the density of apoptotic bodies. The extent to which these changes in microglia are driven by developmental neuronal apoptosis was assessed in tissues from BAX null mice lacking apoptosis. We found that apoptosis can lead to local microglial accumulation near apoptotic neurons in the pyramidal cell body layer but, unexpectedly, loss of apoptosis did not alter overall microglial cell density in vivo or microglial motility and migration in ex vivo tissue slices. These results demonstrate that developmental changes in microglial form, distribution, motility, and migration occur essentially normally in the absence of developmental apoptosis, indicating that factors other than neuronal apoptosis regulate these features of microglial development.
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Filosa JA, Morrison HW, Iddings JA, Du W, Kim KJ. Beyond neurovascular coupling, role of astrocytes in the regulation of vascular tone. Neuroscience 2016; 323:96-109. [PMID: 25843438 PMCID: PMC4592693 DOI: 10.1016/j.neuroscience.2015.03.064] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 12/22/2022]
Abstract
The brain possesses two intricate mechanisms that fulfill its continuous metabolic needs: cerebral autoregulation, which ensures constant cerebral blood flow over a wide range of arterial pressures and functional hyperemia, which ensures rapid delivery of oxygen and glucose to active neurons. Over the past decade, a number of important studies have identified astrocytes as key intermediaries in neurovascular coupling (NVC), the mechanism by which active neurons signal blood vessels to change their diameter. Activity-dependent increases in astrocytic Ca(2+) activity are thought to contribute to the release of vasoactive substances that facilitate arteriole vasodilation. A number of vasoactive signals have been identified and their role on vessel caliber assessed both in vitro and in vivo. In this review, we discuss mechanisms implicating astrocytes in NVC-mediated vascular responses, limitations encountered as a result of the challenges in maintaining all the constituents of the neurovascular unit intact and deliberate current controversial findings disputing a main role for astrocytes in NVC. Finally, we briefly discuss the potential role of pericytes and microglia in NVC-mediated processes.
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Affiliation(s)
- J A Filosa
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States.
| | - H W Morrison
- University of Arizona, 1305 N. Martin Avenue, P.O. Box 210203, Tucson, AZ 85721, United States
| | - J A Iddings
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
| | - W Du
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
| | - K J Kim
- Georgia Regents University, 1120 15th Street, Augusta, GA 30912, United States
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Communication from the periphery to the hypothalamus through the blood–brain barrier: An in vitro platform. Int J Pharm 2016; 499:119-130. [DOI: 10.1016/j.ijpharm.2015.12.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/18/2015] [Accepted: 12/20/2015] [Indexed: 12/26/2022]
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Nakadate K, Tanaka-Nakadate S. Three-Dimensional Electron Microscopy Reconstruction of Degenerative Dopaminergic Neurons Surrounded by Activated Microglia in Substantia Nigra. Ultrastruct Pathol 2015; 39:369-77. [PMID: 26111207 DOI: 10.3109/01913123.2015.1042609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There is an urgent need to investigate the reason for the pathogenic mechanism of intractable central neurological diseases such as Parkinson's disease. It has been reported that the activation of microglial cells is involved in the pathology of these diseases. However, due to technical difficulties, the relationship between degenerative neurons and activated microglial cells remains unclear. Therefore, we tried the improved analysis technique to clarify the spatial relationship between these cell types. We were able to establish an analysis technique that consists of a three-dimensional reconstruction method using serial immunoelectron micrographs after having identified both degenerative neurons and activated microglial cells under optical microscope. Using this technique, we have relatively easily been able to clarify the spatial relationship between degenerative neurons and activated microglial cells. Furthermore, using this technique it is possible to determine the neuronal degeneration process in detail, because it is able to identify structures implicated in degeneration, such as accumulation of lipofuscin in degenerated neuronal somata and phagocytotic structures of microglial cells. In future, this technical approach may be applied to elucidate the relationship between degenerative neurons and activated glial cells in human diseases.
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Affiliation(s)
- Kazuhiko Nakadate
- a Department of Basic Science , Educational and Research Center for Pharmacy, Meiji Pharmaceutical University , Tokyo , Japan and
| | - Sawako Tanaka-Nakadate
- b Department of Pharmacology and Toxicology , Dokkyo Medical University School of Medicine , Tochigi , Japan
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Haley SA, O'Hara BA, Nelson CDS, Brittingham FLP, Henriksen KJ, Stopa EG, Atwood WJ. Human polyomavirus receptor distribution in brain parenchyma contrasts with receptor distribution in kidney and choroid plexus. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2246-58. [PMID: 26056932 DOI: 10.1016/j.ajpath.2015.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/21/2015] [Accepted: 04/14/2015] [Indexed: 11/25/2022]
Abstract
The human polyomavirus, JCPyV, is the causative agent of progressive multifocal leukoencephalopathy, a rare demyelinating disease that occurs in the setting of prolonged immunosuppression. After initial asymptomatic infection, the virus establishes lifelong persistence in the kidney and possibly other extraneural sites. In rare instances, the virus traffics to the central nervous system, where oligodendrocytes, astrocytes, and glial precursors are susceptible to lytic infection, resulting in progressive multifocal leukoencephalopathy. The mechanisms by which the virus traffics to the central nervous system from peripheral sites remain unknown. Lactoseries tetrasaccharide c (LSTc), a pentasaccharide containing a terminal α2,6-linked sialic acid, is the major attachment receptor for polyomavirus. In addition to LSTc, type 2 serotonin receptors are required for facilitating virus entry into susceptible cells. We studied the distribution of virus receptors in kidney and brain using lectins, antibodies, and labeled virus. The distribution of LSTc, serotonin receptors, and virus binding sites overlapped in kidney and in the choroid plexus. In brain parenchyma, serotonin receptors were expressed on oligodendrocytes and astrocytes, but these cells were negative for LSTc and did not bind virus. LSTc was instead found on microglia and vascular endothelium, to which virus bound abundantly. Receptor distribution was not changed in the brains of patients with progressive multifocal leukoencephalopathy. Virus infection of oligodendrocytes and astrocytes during disease progression is LSTc independent.
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Affiliation(s)
- Sheila A Haley
- Department of Molecular Biology, Cell Biology and Biochemistry, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Bethany A O'Hara
- Department of Molecular Biology, Cell Biology and Biochemistry, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Christian D S Nelson
- Department of Molecular Biology, Cell Biology and Biochemistry, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Frances L P Brittingham
- Department of Molecular Biology, Cell Biology and Biochemistry, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Kammi J Henriksen
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Edward G Stopa
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Walter J Atwood
- Department of Molecular Biology, Cell Biology and Biochemistry, Warren Alpert Medical School, Brown University, Providence, Rhode Island.
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Kälin S, Heppner FL, Bechmann I, Prinz M, Tschöp MH, Yi CX. Hypothalamic innate immune reaction in obesity. Nat Rev Endocrinol 2015; 11:339-51. [PMID: 25824676 DOI: 10.1038/nrendo.2015.48] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Findings from rodent and human studies show that the presence of inflammatory factors is positively correlated with obesity and the metabolic syndrome. Obesity-associated inflammatory responses take place not only in the periphery but also in the brain. The hypothalamus contains a range of resident glial cells including microglia, macrophages and astrocytes, which are embedded in highly heterogenic groups of neurons that control metabolic homeostasis. This complex neural-glia network can receive information directly from blood-borne factors, positioning it as a metabolic sensor. Following hypercaloric challenge, mediobasal hypothalamic microglia and astrocytes enter a reactive state, which persists during diet-induced obesity. In established mouse models of diet-induced obesity, the hypothalamic vasculature displays angiogenic alterations. Moreover, proopiomelanocortin neurons, which regulate food intake and energy expenditure, are impaired in the arcuate nucleus, where there is an increase in local inflammatory signals. The sum total of these events is a hypothalamic innate immune reactivity, which includes temporal and spatial changes to each cell population. Although the exact role of each participant of the neural-glial-vascular network is still under exploration, therapeutic targets for treating obesity should probably be linked to individual cell types and their specific signalling pathways to address each dysfunction with cell-selective compounds.
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Affiliation(s)
- Stefanie Kälin
- Institute for Diabetes and Obesity, Helmholtz Centre for Health and Environment &Technische Universität München, 85748, Munich, Germany
| | - Frank L Heppner
- Department of Neuropathology, Charité, Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Ingo Bechmann
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany
| | - Marco Prinz
- Institute of Neuropathology, University of Freiburg, Breisacher Str. 64, D-79106 Freiburg, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Centre for Health and Environment &Technische Universität München, 85748, Munich, Germany
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, Netherlands
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Spanos JP, Hsu NJ, Jacobs M. Microglia are crucial regulators of neuro-immunity during central nervous system tuberculosis. Front Cell Neurosci 2015; 9:182. [PMID: 26041993 PMCID: PMC4435040 DOI: 10.3389/fncel.2015.00182] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/27/2015] [Indexed: 01/11/2023] Open
Abstract
Mycobacterium tuberculosis (M. tuberculosis) infection of the central nervous system (CNS) is the most devastating manifestation of tuberculosis (TB), with both high mortality and morbidity. Although research has been fueled by the potential therapeutic target microglia offer against neurodegenerative inflammation, their part in TB infection of the CNS has not been fully evaluated nor elucidated. Yet, as both the preferential targets of M. tuberculosis and the immune-effector cells of the CNS, microglia are likely to be key determinants of disease severity and clinical outcomes. Following pathogen recognition, bacilli are internalized and capable of replicating within microglia. Cellular activation ensues, utilizing signaling molecules that may be neurotoxic. Central to initiating, orchestrating and modulating the tuberculous immune response is microglial secretion of cytokines and chemokines. However, the neurological environment is unique in that inflammatory signals, which appear to be damaging in the periphery, could be beneficial by governing neuronal survival, regeneration and differentiation. Furthermore, microglia are important in the recruitment of peripheral immune cells and central to defining the pro-inflammatory milieu of which neurotoxicity may result from many of the participating local or recruited cell types. Microglia are capable of both presenting antigen to infiltrating CD4(+) T-lymphocytes and inducing their differentiation-a possible correlate of protection against M. tuberculosis infection. Clarifying the nature of the immune effector molecules secreted by microglia, and the means by which other CNS-specific cell types govern microglial activation or modulate their responses is critical if improved diagnostic and therapeutic strategies are to be attained. Therefore, this review evaluates the diverse roles microglia play in the neuro-immunity to M. tuberculosis infection of the CNS.
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Affiliation(s)
- Jonathan Paul Spanos
- Division of Immunology, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town Cape Town, South Africa
| | - Nai-Jen Hsu
- Division of Immunology, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town Cape Town, South Africa
| | - Muazzam Jacobs
- Division of Immunology, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town Cape Town, South Africa ; National Health Laboratory Service Johannesburg, South Africa
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Nowlin BT, Burdo TH, Midkiff CC, Salemi M, Alvarez X, Williams KC. SIV encephalitis lesions are composed of CD163(+) macrophages present in the central nervous system during early SIV infection and SIV-positive macrophages recruited terminally with AIDS. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:1649-65. [PMID: 25963554 DOI: 10.1016/j.ajpath.2015.01.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/16/2015] [Accepted: 01/30/2015] [Indexed: 10/23/2022]
Abstract
Macrophage recruitment to the central nervous system (CNS) during AIDS pathogenesis is poorly understood. We measured the accumulation of brain perivascular (CD163(+)) and inflammatory (MAC387(+)) macrophages in SIV-infected monkeys. Monocyte progenitors were 5-bromo-2'-deoxyuridine (BrdU) labeled in bone marrow, and CNS macrophages were labeled serially with fluorescent dextrans injected into the cisterna magna. MAC387(+) macrophages accumulated in the meninges and choroid plexus in early inflammation and in the perivascular space and SIV encephalitis (SIVE) lesions late. CD163(+) macrophages accumulated in the perivascular space and SIVE lesions with late inflammation. Most of the BrdU(+) cells were MAC387(+); however, CD163(+)BrdU(+) macrophages were present in the meninges and choroid plexus with AIDS. Most (81.6% ± 1.8%) of macrophages in SIVE lesions were present in the CNS before SIVE lesion formation. There was a 2.9-fold increase in SIVp28(+) macrophages entering the CNS late compared with those entering early (P < 0.05). The rate of CD163(+) macrophage recruitment to the CNS inversely correlated with time to death (P < 0.03) and increased with SIVE. In SIVE animals, soluble CD163 correlated with CD163(+) macrophage recruitment (P = 0.02). Most perivascular macrophages that comprise SIVE lesions and multinucleated giant cells are present in the CNS early, before SIVE lesions are formed. Most SIV-infected macrophages traffic to the CNS terminally with AIDS.
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Affiliation(s)
- Brian T Nowlin
- Biology Department, Boston College, Chestnut Hill, Massachusetts
| | - Tricia H Burdo
- Biology Department, Boston College, Chestnut Hill, Massachusetts
| | - Cecily C Midkiff
- Division of Comparative Pathology, Tulane National Primate Research Center, Tulane University Health Science Center, Covington, Louisiana
| | - Marco Salemi
- Department of Pathology, Immunology, and Laboratory Medicine, Emerging Pathogens Institute, University of Florida, Gainesville, Florida
| | - Xavier Alvarez
- Division of Comparative Pathology, Tulane National Primate Research Center, Tulane University Health Science Center, Covington, Louisiana
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Chim SM, Kuek V, Chow ST, Lim BS, Tickner J, Zhao J, Chung R, Su YW, Zhang G, Erber W, Xian CJ, Rosen V, Xu J. EGFL7 is expressed in bone microenvironment and promotes angiogenesis via ERK, STAT3, and integrin signaling cascades. J Cell Physiol 2015; 230:82-94. [PMID: 24909139 DOI: 10.1002/jcp.24684] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 05/21/2014] [Indexed: 12/18/2022]
Abstract
Angiogenesis plays a pivotal role in bone formation, remodeling, and fracture healing. The regulation of angiogenesis in the bone microenvironment is highly complex and orchestrated by intercellular communication between bone cells and endothelial cells. Here, we report that EGF-like domain 7 (EGFL7), a member of the epidermal growth factor (EGF) repeat protein superfamily is expressed in both the osteoclast and osteoblast lineages, and promotes endothelial cell activities. Addition of exogenous recombinant EGFL7 potentiates SVEC (simian virus 40-transformed mouse microvascular endothelial cell line) cell migration and tube-like structure formation in vitro. Moreover, recombinant EGFL7 promotes angiogenesis featuring web-like structures in ex vivo fetal mouse metatarsal angiogenesis assay. We show that recombinant EGFL7 induces phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), signal transducer and activator of transcription 3 (STAT3), and focal adhesion kinase (FAK) in SVEC cells. Inhibition of ERK1/2 and STAT3 signaling impairs EGFL7-induced endothelial cell migration, and angiogenesis in fetal mouse metatarsal explants. Bioinformatic analyses indicate that EGFL7 contains a conserved RGD/QGD motif and EGFL7-induced endothelial cell migration is significantly reduced in the presence of RGD peptides. Moreover, EGFL7 gene expression is significantly upregulated during growth plate injury repair. Together, these results demonstrate that EGFL7 expressed by bone cells regulates endothelial cell activities through integrin-mediated signaling. This study highlights the important role that EGFL7, like EGFL6, expressed in bone microenvironment plays in the regulation of angiogenesis in bone.
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Affiliation(s)
- Shek Man Chim
- School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, WA, Australia
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Liu M, Li J, Dai P, Zhao F, Zheng G, Jing J, Wang J, Luo W, Chen J. Microglia activation regulates GluR1 phosphorylation in chronic unpredictable stress-induced cognitive dysfunction. Stress 2015; 18:96-106. [PMID: 25472821 DOI: 10.3109/10253890.2014.995085] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Chronic stress is considered to be a major risk factor in the development of psychopathological syndromes in humans. Cognitive impairments and long-term potentiation (LTP) impairments are increasingly recognized as major components of depression, anxiety disorders and other stress-related chronic psychological illnesses. It seems timely to systematically study the potentially underlying neurobiological mechanisms of altered cognitive and synaptic plasticity in the course of chronic stress. In the present study, a rat model of chronic unpredictable stress (CUS) induced a cognitive impairment in spatial memory in the Morris water maze (MWM) test and a hippocampal LTP impairment. CUS also induced hippocampal microglial activation and attenuated phosphorylation of glutamate receptor 1 (GluR1 or GluA1). Moreover, chronic treatment with the selective microglial activation blocker, minocycline (120 mg/kg per day), beginning 3 d before CUS treatment and continuing through the behavioral testing period, prevented the CUS-induced impairments of spatial memory and LTP induction. Additional studies showed that minocycline-induced inhibition of microglia activation was associated with increased phosphorylation of GluR1. These results suggest that hippocampal microglial activation modulates the level of GluR1 phosphorylation and might play a causal role in CUS-induced cognitive and LTP disturbances.
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Affiliation(s)
- Mingchao Liu
- Department of Occupational & Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University , Xi'an , China and
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Abstract
Immune functions in the brain are associated with psychiatric illness and temporary alteration of mental state. Microglia, the principal brain immunologic cells, respond to changes in the internal brain milieu through a sequence of activated states, each with characteristic function and morphology. To assess a possible association of frontal white matter pathology with suicide, we stained autopsy brain tissue samples from 11 suicide and 25 nonsuicide subjects for ionized calcium-binding adapter molecule 1, cluster of differentiation 68, and myelin. Groups were matched by age, sex, and psychiatric diagnosis. We classified ionized calcium-binding adapter molecule 1-immunoreactive cells based on shape, immunoreactivity to cluster of differentiation 68, and association with blood vessels to obtain stereologic estimates of densities of resting microglia, activated phagocytes, and perivascular cells. We found no effect of psychiatric diagnosis but 2 statistically significant effects of suicide: 1) The dorsal-ventral difference in activated microglial density was reversed such that, with suicide, the density was greater in ventral prefrontal white matter than in dorsal prefrontal white matter, whereas in the absence of suicide, the opposite was true; and 2) with suicide, there was a greater density of ionized calcium-binding adapter molecule 1-immunoreactive cells within or in contact with blood vessel walls in dorsal prefrontal white matter. These observations could reflect a mechanism for the stress/diathesis (state/trait) model of suicide, whereby an acute stress activates a reactive process in the brain, either directly or by compromising the blood-brain barrier, and creates a suicidal state in an individual at risk. They also indicate the theoretical potential of imaging studies in living vulnerable individuals for the assessment of suicide risk. Further studies are needed to investigate specific phenotypes of perivascular cells and blood-brain barrier changes associated with suicide.
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