1
|
Mercurio D, Fumagalli S, Schafer MKH, Pedragosa J, Ngassam LDC, Wilhelmi V, Winterberg S, Planas AM, Weihe E, De Simoni MG. Protein Expression of the Microglial Marker Tmem119 Decreases in Association With Morphological Changes and Location in a Mouse Model of Traumatic Brain Injury. Front Cell Neurosci 2022; 16:820127. [PMID: 35221925 PMCID: PMC8866855 DOI: 10.3389/fncel.2022.820127] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/11/2022] [Indexed: 01/08/2023] Open
Abstract
The activation of microglia and the infiltration of macrophages are hallmarks of neuroinflammation after acute brain injuries, including traumatic brain injury (TBI). The two myeloid populations share many features in the post-injury inflammatory response, thus, being antigenically indistinguishable. Recently Tmem119, a type I transmembrane protein specifically expressed by microglia under physiological conditions, was proposed as a tool to differentiate resident microglia from blood-borne macrophages, not expressing it. However, the validity of Tmem119 as a specific marker of resident microglia in the context of acute brain injury, where microglia are activated and macrophages are recruited, needs validation. Our purpose was to investigate Tmem119 expression and distribution in relation to the morphology of brain myeloid cells present in the injured area after TBI. Mice underwent sham surgery or TBI by controlled cortical impact (CCI). Brains from sham-operated, or TBI mice, were analyzed by in situ hybridization to identify the cells expressing Tmem119, and by Western blot and quantitative immunofluorescence to measure Tmem119 protein levels in the entire brain regions and single cells. The morphology of Iba1+ myeloid cells was analyzed at different times (4 and 7 days after TBI) and several distances from the contused edge in order to associate Tmem119 expression with morphological evolution of active microglia. In situ hybridization indicated an increased Tmem119 RNA along with increased microglial complement C1q activation in the contused area and surrounding regions. On the contrary, the biochemical evaluation showed a drop in Tmem119 protein levels in the same areas. The Tmem119 immunoreactivity decreased in Iba1+ myeloid cells found in the contused cortex at both time points, with the cells showing the hypertrophic ameboid morphology having no Tmem119 expression. The Tmem119 was present on ramifications of resident microglia and its presence was decreased as a consequence of microglial activation in cortical areas close to contusion. Based on the data, we conclude that the decrease of Tmem119 in reactive microglia may depend on the process of microglial activation, which involves the retracting of their branchings to acquire an ameboid shape. The Tmem119 immunoreactivity decreases in reactive microglia to similar levels than the blood-borne macrophages, thus, failing to discriminate the two myeloid populations after TBI.
Collapse
Affiliation(s)
- Domenico Mercurio
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Stefano Fumagalli
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Martin K-H Schafer
- Institute of Anatomy and Cell Biology, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Jordi Pedragosa
- Department of Neuroscience and Experimental Therapeutics, Institute for Biomedical Research of Barcelona, Spanish National Research Council (CSIC), Barcelona, Spain
| | | | - Verena Wilhelmi
- Institute of Anatomy and Cell Biology, University of Marburg, Marburg, Germany
| | - Sarah Winterberg
- Institute of Anatomy and Cell Biology, University of Marburg, Marburg, Germany
| | - Anna M Planas
- Department of Neuroscience and Experimental Therapeutics, Institute for Biomedical Research of Barcelona, Spanish National Research Council (CSIC), Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Eberhard Weihe
- Institute of Anatomy and Cell Biology, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Maria-Grazia De Simoni
- Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| |
Collapse
|
2
|
Abstract
The notion that autoimmune responses to α-synuclein may be involved in the pathogenesis of this disorder stems from reports that mutations in α-synuclein or certain alleles of the major histocompatibility complex (MHC) are associated with the disease and that dopaminergic and norepinephrinergic neurons in the midbrain can present antigenic epitopes. Here, we discuss recent evidence that a defined set of peptides derived from α-synuclein act as antigenic epitopes displayed by specific MHC alleles and drive helper and cytotoxic T cell responses in patients with PD. Moreover, phosphorylated α-synuclein may activate T cell responses in a less restricted manner in PD. While the roles for the acquired immune system in disease pathogenesis remain unknown, preclinical animal models and in vitro studies indicate that T cells may interact with neurons and exert effects related to neuronal death and neuroprotection. These findings suggest that therapeutics that target T cells and ameliorate the incidence or disease severity of inflammatory bowel disorders or CNS autoimmune diseases such as multiple sclerosis may be useful in PD.
Collapse
|
3
|
Potential Effects of Leukotriene Receptor Antagonist Montelukast in Treatment of Neuroinflammation in Parkinson's Disease. Int J Mol Sci 2021; 22:ijms22115606. [PMID: 34070609 PMCID: PMC8198163 DOI: 10.3390/ijms22115606] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/16/2021] [Accepted: 05/21/2021] [Indexed: 12/11/2022] Open
Abstract
Parkinson’s disease (PD) is a neurodegenerative disorder where misfolded alpha-synuclein-enriched aggregates called Lewy bodies are central in pathogenesis. No neuroprotective or disease-modifying treatments are currently available. Parkinson’s disease is considered a multifactorial disease and evidence from multiple patient studies and animal models has shown a significant immune component during the course of the disease, highlighting immunomodulation as a potential treatment strategy. The immune changes occur centrally, involving microglia and astrocytes but also peripherally with changes to the innate and adaptive immune system. Here, we review current understanding of different components of the PD immune response with a particular emphasis on the leukotriene pathway. We will also describe evidence of montelukast, a leukotriene receptor antagonist, as a possible anti-inflammatory treatment for PD.
Collapse
|
4
|
van de Wouw M, Boehme M, Dinan TG, Cryan JF. Monocyte mobilisation, microbiota & mental illness. Brain Behav Immun 2019; 81:74-91. [PMID: 31330299 DOI: 10.1016/j.bbi.2019.07.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/12/2019] [Accepted: 07/18/2019] [Indexed: 12/13/2022] Open
Abstract
The gastrointestinal microbiome has emerged as a key player in regulating brain and behaviour. This has led to the strategy of targeting the gut microbiota to ameliorate disorders of the central nervous system. Understanding the underlying signalling pathways in which the microbiota impacts these disorders is crucial for the development of future therapeutics for improving CNS functionality. One of the major pathways through which the microbiota influences the brain is the immune system, where there is an increasing appreciation for the role of monocyte trafficking in regulating brain homeostasis. In this review, we will shed light on the role of monocyte trafficking as a relay of microbiota signals in conditions where the central nervous system is in disorder, such as stress, peripheral inflammation, ageing, traumatic brain injury, stroke, multiple sclerosis, Alzheimer's disease and Parkinson's disease. We also cover how the gastrointestinal microbiota is implicated in these mental illnesses. In addition, we aim to discuss how the monocyte system can be modulated by the gut microbiota to mitigate disorders of the central nervous system, which will lead to novel microbiota-targeted strategies.
Collapse
Affiliation(s)
| | - Marcus Boehme
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Psychiatry and Neurobehavioral Science, University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Ireland, University College Cork, Cork, Ireland; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| |
Collapse
|
5
|
Garretti F, Agalliu D, Lindestam Arlehamn CS, Sette A, Sulzer D. Autoimmunity in Parkinson's Disease: The Role of α-Synuclein-Specific T Cells. Front Immunol 2019; 10:303. [PMID: 30858851 PMCID: PMC6397885 DOI: 10.3389/fimmu.2019.00303] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/06/2019] [Indexed: 12/23/2022] Open
Abstract
Evidence from a variety of studies implicates a role for the adaptive immune system in Parkinson's disease (PD). Similar to multiple sclerosis (MS) patients who display a high number of T cells in the brain attacking oligodendrocytes, PD patients show higher numbers of T cells in the ventral midbrain than healthy, age-matched controls. Mouse models of the disease also show the presence of T cells in the brain. The role of these infiltrating T cells in the propagation of disease is controversial; however, recent studies indicate that they may be autoreactive in nature, recognizing disease-altered self-proteins as foreign antigens. T cells of PD patients can generate an autoimmune response to α-synuclein, a protein that is aggregated in PD. α-Synuclein and other proteins are post-translationally modified in an environment in which protein processing is altered, possibly leading to the generation of neo-epitopes, or self-peptides that have not been identified by the host immune system as non-foreign. Infiltrating T cells may also be responding to such modified proteins. Genome-wide association studies (GWAS) have shown associations of PD with haplotypes of major histocompatibility complex (MHC) class II genes, and a polymorphism in a non-coding region that may increase MHC class II in PD patients. We speculate that the inflammation observed in PD may play both pathogenic and protective roles. Future studies on the adaptive immune system in neurodegenerative disorders may elucidate steps in disease pathogenesis and assist with the development of both biomarkers and treatments.
Collapse
Affiliation(s)
- Francesca Garretti
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
| | - Dritan Agalliu
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States.,Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | | | - Alessandro Sette
- Division of Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, United States.,Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States.,Department of Pharmacology, Columbia University Irving Medical Center, New York, NY, United States.,Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, United States
| |
Collapse
|
6
|
Younger D, Murugan M, Rama Rao KV, Wu LJ, Chandra N. Microglia Receptors in Animal Models of Traumatic Brain Injury. Mol Neurobiol 2018; 56:5202-5228. [DOI: 10.1007/s12035-018-1428-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/13/2018] [Indexed: 02/07/2023]
|
7
|
Williams GP, Schonhoff AM, Jurkuvenaite A, Thome AD, Standaert DG, Harms AS. Targeting of the class II transactivator attenuates inflammation and neurodegeneration in an alpha-synuclein model of Parkinson's disease. J Neuroinflammation 2018; 15:244. [PMID: 30165873 PMCID: PMC6117927 DOI: 10.1186/s12974-018-1286-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/20/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Parkinson's disease (PD) is characterized by intracellular alpha-synuclein (α-syn) inclusions, progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and activation of the innate and adaptive immune systems. Disruption of immune signaling between the central nervous system (CNS) and periphery, such as through targeting the chemokine receptor type 2 (CCR2) or the major histocompatibility complex II (MHCII), is neuroprotective in rodent models of PD, suggesting a key role for innate and adaptive immunity in disease progression. The purpose of this study was to investigate whether genetic knockout or RNA silencing of the class II transactivator (CIITA), a transcriptional co-activator required for MHCII induction, is effective in reducing the neuroinflammation and neurodegeneration observed in an α-syn mouse model of PD. METHODS In vitro, we utilized microglia cultures from WT or CIITA -/- mice treated with α-syn fibrils to investigate inflammatory iNOS expression and antigen processing via immunocytochemistry (ICC). In vivo, an adeno-associated virus (AAV) was used to overexpress α-syn in WT and CIITA -/- mice as a model for PD. Concurrently with AAV-mediated overexpression of α-syn, WT mice received CIITA-targeted shRNAs packaged in lentiviral constructs. Immunohistochemistry and flow cytometry were used to assess inflammation and peripheral cell infiltration at 4 weeks post transduction, and unbiased stereology was used 6 months post transduction to assess neurodegeneration. RESULTS Using ICC and DQ-ovalbumin, we show that CIITA -/- microglial cultures failed to upregulate iNOS and MHCII expression, and had decreased antigen processing in response to α-syn fibrils when compared to WT microglia. In vivo, global knock-out of CIITA as well as local knockdown using lentiviral shRNAs targeting CIITA attenuated MHCII expression, peripheral immune cell infiltration, and α-syn-induced neurodegeneration. CONCLUSION Our data provide evidence that CIITA is required for α-syn-induced MHCII induction and subsequent infiltration of peripheral immune cells in an α-syn mouse model of PD. Additionally, we demonstrate that CIITA in the CNS drives neuroinflammation and neurodegeneration. These data provide further support that the disruption or modulation of antigen processing and presentation via CIITA is a promising target for therapeutic development in preclinical animal models of PD.
Collapse
Affiliation(s)
- Gregory P Williams
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham (UAB), 1719 6th Ave. South, CIRC 525, Birmingham, AL, 35294-0021, USA
| | - Aubrey M Schonhoff
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham (UAB), 1719 6th Ave. South, CIRC 525, Birmingham, AL, 35294-0021, USA
| | - Asta Jurkuvenaite
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham (UAB), 1719 6th Ave. South, CIRC 525, Birmingham, AL, 35294-0021, USA
| | - Aaron D Thome
- Department of Neurology, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - David G Standaert
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham (UAB), 1719 6th Ave. South, CIRC 525, Birmingham, AL, 35294-0021, USA
| | - Ashley S Harms
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham (UAB), 1719 6th Ave. South, CIRC 525, Birmingham, AL, 35294-0021, USA.
| |
Collapse
|
8
|
Claes C, Van den Daele J, Verfaillie CM. Generating tissue-resident macrophages from pluripotent stem cells: Lessons learned from microglia. Cell Immunol 2018; 330:60-67. [PMID: 29433896 DOI: 10.1016/j.cellimm.2018.01.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 02/07/2023]
Abstract
Over the past decades, the importance of the immune system in a broad scope of pathologies, has drawn attention towards tissue-resident macrophages, such as microglia in the brain. To enable the study of for instance microglia, it is crucial to recreate in vitro (and in vivo) assays. However, very fast loss of tissue-specific features of primary tissue resident macrophages, including microglia, upon in vitro culture has complicated such studies. Moreover, limited knowledge of macrophage developmental pathways and the role of local 'niche factors', has hampered the generation of tissue-resident macrophages from pluripotent stem cells (PSC). Recent data on the ontogeny of tissue-resident macrophages, combined with bulk and single cell RNAseq studies have identified the distinct origins and gene profile of microglia compared to other myeloid cells. As a result, over the past years, protocols have been published to create hPSC-derived microglia-'like' cells, as these cells are considered potential new therapeutic targets for therapies to treat neurodegenerative diseases. In this review we will provide an overview of different approaches taken to generate human microglia in vitro, taking into account their origin, and resemblance to their in vivo counterpart. Finally, we will discuss cell-extrinsic (culture conditions) and intrinsic factors (transcriptional machinery and epigenetics) that we believe can improve future differentiation protocols of tissue-resident macrophages from stem cells.
Collapse
Affiliation(s)
- Christel Claes
- Department of Development and Regeneration, Stem Cell and Developmental Biology, Stem Cell Institute Leuven, KU Leuven, Leuven, Belgium
| | - Johanna Van den Daele
- Department of Development and Regeneration, Stem Cell and Developmental Biology, Stem Cell Institute Leuven, KU Leuven, Leuven, Belgium
| | - Catherine M Verfaillie
- Department of Development and Regeneration, Stem Cell and Developmental Biology, Stem Cell Institute Leuven, KU Leuven, Leuven, Belgium.
| |
Collapse
|
9
|
Harms AS, Thome AD, Yan Z, Schonhoff AM, Williams GP, Li X, Liu Y, Qin H, Benveniste EN, Standaert DG. Peripheral monocyte entry is required for alpha-Synuclein induced inflammation and Neurodegeneration in a model of Parkinson disease. Exp Neurol 2017; 300:179-187. [PMID: 29155051 DOI: 10.1016/j.expneurol.2017.11.010] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 11/06/2017] [Accepted: 11/15/2017] [Indexed: 12/18/2022]
Abstract
Accumulation of alpha-synuclein (α-syn) in the central nervous system (CNS) is a core feature of Parkinson disease (PD) that leads to activation of the innate immune system, production of inflammatory cytokines and chemokines, and subsequent neurodegeneration. Here, we used heterozygous reporter knock-in mice in which the first exons of the fractalkine receptor (CX3CR1) and of the C-C chemokine receptor type 2 (CCR2) are replaced with fluorescent reporters to study the role of resident microglia (CX3CR1+) and infiltrating peripheral monocytes (CCR2+), respectively, in the CNS. We used an α-syn mouse model induced by viral over-expression of α-syn. We find that in vivo, expression of full-length human α-syn induces robust infiltration of pro-inflammatory CCR2+ peripheral monocytes into the substantia nigra. Genetic deletion of CCR2 prevents α-syn induced monocyte entry, attenuates MHCII expression and blocks the subsequent degeneration of dopaminergic neurons. These results demonstrate that extravasation of pro-inflammatory peripheral monocytes into the CNS plays a key role in neurodegeneration in this model of PD synucleinopathy, and suggest that peripheral monocytes may be a target of neuroprotective therapies for human PD.
Collapse
Affiliation(s)
- Ashley S Harms
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Aaron D Thome
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Zhaoqi Yan
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Aubrey M Schonhoff
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Gregory P Williams
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Xinru Li
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Yudong Liu
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Hongwei Qin
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Etty N Benveniste
- Department of Cell, Developmental and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - David G Standaert
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| |
Collapse
|
10
|
Meyer K, Kaspar BK. Glia-neuron interactions in neurological diseases: Testing non-cell autonomy in a dish. Brain Res 2017; 1656:27-39. [PMID: 26778174 PMCID: PMC4939136 DOI: 10.1016/j.brainres.2015.12.051] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 12/30/2022]
Abstract
For the past century, research on neurological disorders has largely focused on the most prominently affected cell types - the neurons. However, with increasing knowledge of the diverse physiological functions of glial cells, their impact on these diseases has become more evident. Thus, many conditions appear to have more complex origins than initially thought. Since neurological pathologies are often sporadic with unknown etiology, animal models are difficult to create and might only reflect a small portion of patients in which a mutation in a gene has been identified. Therefore, reliable in vitro systems to studying these disorders are urgently needed. They might be a pre-requisite for improving our understanding of the disease mechanisms as well as for the development of potential new therapies. In this review, we will briefly summarize the function of different glial cell types in the healthy central nervous system (CNS) and outline their implication in the development or progression of neurological conditions. We will then describe different types of culture systems to model non-cell autonomous interactions in vitro and evaluate advantages and disadvantages. This article is part of a Special Issue entitled SI: Exploiting human neurons.
Collapse
Affiliation(s)
- Kathrin Meyer
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Brian K Kaspar
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Molecular, Cellular & Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA.
| |
Collapse
|
11
|
Reemst K, Noctor SC, Lucassen PJ, Hol EM. The Indispensable Roles of Microglia and Astrocytes during Brain Development. Front Hum Neurosci 2016; 10:566. [PMID: 27877121 PMCID: PMC5099170 DOI: 10.3389/fnhum.2016.00566] [Citation(s) in RCA: 344] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 01/17/2023] Open
Abstract
Glia are essential for brain functioning during development and in the adult brain. Here, we discuss the various roles of both microglia and astrocytes, and their interactions during brain development. Although both cells are fundamentally different in origin and function, they often affect the same developmental processes such as neuro-/gliogenesis, angiogenesis, axonal outgrowth, synaptogenesis and synaptic pruning. Due to their important instructive roles in these processes, dysfunction of microglia or astrocytes during brain development could contribute to neurodevelopmental disorders and potentially even late-onset neuropathology. A better understanding of the origin, differentiation process and developmental functions of microglia and astrocytes will help to fully appreciate their role both in the developing as well as in the adult brain, in health and disease.
Collapse
Affiliation(s)
- Kitty Reemst
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Stephen C. Noctor
- Department of Psychiatry and Behavioral Sciences, UC Davis MIND InstituteSacramento, CA, USA
| | - Paul J. Lucassen
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
| | - Elly M. Hol
- Swammerdam Institute for Life Sciences, University of AmsterdamAmsterdam, Netherlands
- Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center UtrechtUtrecht, Netherlands
- Netherlands Institute for NeuroscienceAmsterdam, Netherlands
| |
Collapse
|
12
|
Abstract
Historically, the brain has been considered an immune-privileged organ separated from the peripheral immune system by the blood-brain barrier. However, immune responses do occur in the brain in neurological conditions in which the integrity of the blood-brain barrier is compromised, exposing the brain to peripheral antigens and endogenous danger signals. While most of the associated pathological processes occur in the central nervous system, it is now clear that peripheral immune cells, especially mononuclear phagocytes, that infiltrate into the injury site play a key role in modulating the progression of primary brain injury development. As inflammation is a necessary and critical component for the subsequent injury resolution process, understanding the contribution of mononuclear phagocytes on the regulation of inflammatory responses may provide novel approaches for potential therapies. Furthermore, predisposed comorbid conditions at the time of stroke cause the alteration of stroke-induced immune and inflammatory responses and subsequently influence stroke outcome. In this review, we summarize a role for microglia and monocytes/macrophages in acute ischemic stroke in the context of normal and metabolically compromised conditions.
Collapse
Affiliation(s)
- Eunhee Kim
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine at Burke Medical Research Institute, White Plains, NY, 10605, USA
| | - Sunghee Cho
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine at Burke Medical Research Institute, White Plains, NY, 10605, USA.
| |
Collapse
|
13
|
Guest J, Bilgin A, Hokin B, Mori TA, Croft KD, Grant R. Novel relationships between B12, folate and markers of inflammation, oxidative stress and NAD(H) levels, systemically and in the CNS of a healthy human cohort. Nutr Neurosci 2015; 18:355-64. [PMID: 26263423 DOI: 10.1179/1476830515y.0000000041] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To evaluate the relationship between folate, cobalamin (Cbl), and homocysteine (Hcy), and markers of inflammation and oxidative stress within the periphery and central nervous system (CNS) of a healthy human cohort. METHODS Thirty-five matched cerebrospinal fluid (CSF) and plasma samples were collected from consenting participants who required a spinal tap for the administration of anaesthetic. Plasma concentrations of Hcy and both plasma and CSF levels of folate, Cbl, nicotinamide adenine dinucleotide (NAD(H)) and markers of inflammation (interleukin-6, IL-6), and oxidative stress (F2-isoprostanes, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total antioxidant capacity (TAC)) were quantified. RESULTS In the peripheral circulation, positive associations were observed between plasma folate and Cbl, and plasma TAC (P ≤ 0.01; P ≤ 0.01) and plasma NAD(H) (P ≤ 0.05; P ≤ 0.05) levels, respectively. Plasma folate was inversely associated with plasma Hcy concentrations (P ≤ 0.05); however, no statistically significant relationships were observed between plasma Hcy and plasma markers of inflammation, oxidative stress, or [NAD(H)]. Within the CNS plasma Hcy correlated positively with CSF IL-6 (P ≤ 0.01) and negatively with CSF NAD(H) (P ≤ 0.05) concentrations. An inverse association was observed between CSF folate and CSF levels of IL-6 (P ≤ 0.05). Unexpectedly, a positive association between CSF Cbl and CSF 8-OHdG levels was also found (P ≤ 0.01). DISCUSSION These results indicate that folate and Cbl concentrations may influence the levels of oxidative damage, inflammation, and NAD(H), both systemically and within the CNS.
Collapse
|
14
|
Snyder HM, Corriveau RA, Craft S, Faber JE, Greenberg SM, Knopman D, Lamb BT, Montine TJ, Nedergaard M, Schaffer CB, Schneider JA, Wellington C, Wilcock DM, Zipfel GJ, Zlokovic B, Bain LJ, Bosetti F, Galis ZS, Koroshetz W, Carrillo MC. Vascular contributions to cognitive impairment and dementia including Alzheimer's disease. Alzheimers Dement 2015; 11:710-7. [PMID: 25510382 PMCID: PMC4731036 DOI: 10.1016/j.jalz.2014.10.008] [Citation(s) in RCA: 413] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/22/2014] [Accepted: 10/02/2014] [Indexed: 02/07/2023]
Abstract
Scientific evidence continues to demonstrate the linkage of vascular contributions to cognitive impairment and dementia such as Alzheimer's disease. In December, 2013, the Alzheimer's Association, with scientific input from the National Institute of Neurological Disorders and Stroke and the National Heart, Lung and Blood Institute from the National Institutes of Health, convened scientific experts to discuss the research gaps in our understanding of how vascular factors contribute to Alzheimer's disease and related dementia. This manuscript summarizes the meeting and the resultant discussion, including an outline of next steps needed to move this area of research forward.
Collapse
Affiliation(s)
- Heather M Snyder
- Medical & Scientific Relations, Alzheimer's Association, Chicago, IL, USA.
| | - Roderick A Corriveau
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Suzanne Craft
- Department of Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - James E Faber
- Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Knopman
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Bruce T Lamb
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, USA
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Chris B Schaffer
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Julie A Schneider
- Departments of Pathology and Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Cheryl Wellington
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Donna M Wilcock
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Gregory J Zipfel
- Departments of Neurological Surgery and Neurology, Washington University, St Louis, St Louis, MO, USA
| | - Berislav Zlokovic
- Department of Physiology, University of Southern California, Los Angeles, CA, USA
| | - Lisa J Bain
- Independent Science Writer, Elverson, PA, USA
| | - Francesca Bosetti
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zorina S Galis
- National Institute of Heart, Lung and Blood, National Institutes of Health, Bethesda, MD, USA
| | - Walter Koroshetz
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Maria C Carrillo
- Medical & Scientific Relations, Alzheimer's Association, Chicago, IL, USA
| |
Collapse
|
15
|
Zanier ER, Fumagalli S, Perego C, Pischiutta F, De Simoni MG. Shape descriptors of the "never resting" microglia in three different acute brain injury models in mice. Intensive Care Med Exp 2015. [PMID: 26215806 PMCID: PMC4513020 DOI: 10.1186/s40635-015-0039-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The study of microglia and macrophage (M/M) morphology represents a key tool to understand the functional activation state and the pattern of distribution of these cells in acute brain injury. The identification of reliable quantitative morphological parameters is urgently needed to understand these cell roles in brain injury and to explore strategies aimed at therapeutically manipulating the inflammatory response. METHODS We used three different clinically relevant murine models of focal injury, namely, controlled cortical impact brain injury (traumatic brain injury (TBI)) and transient and permanent occlusion of middle cerebral artery (tMCAo and pMCAo, respectively). Twenty-four hours after injury, M/M cells were labeled by CD11b, and ×40 photomicrographs were acquired by unbiased sampling of the lesion core using a motorized stage microscope. Images were processed with Fiji software to obtain shape descriptors. RESULTS We validated several parameters, including area, perimeter, Feret's diameter (caliper), circularity, aspect ratio, and solidity, providing quantitative information on M/M morphology over wide tissue portions. We showed that the shape descriptors that best represent M/M ramification/elongation are area and perimeter, while circularity and solidity provide information on the ameboid shape. We also provide evidence of the involvement of different populations in local inflammatory events, with macrophages replacing microglia into the lesion core when reperfusion does not occur. Analysis of CD45(high)+ cell morphology, whose shape does not change, did not yield any difference, thus confirming the reliability of the approach. CONCLUSIONS We have defined specific morphological features that M/M acquire in response to different acute insults by applying a sensitive and readily applicable approach to cell morphological analysis in the brain tissue. Potential application of this method can be extended to all cell types able to change shape following activation, e.g., astrocytes, or to different disease states, including chronic pathologies.
Collapse
Affiliation(s)
- Elisa R Zanier
- IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Department of Neuroscience, Via La Masa 19, 20156, Milan, Italy,
| | | | | | | | | |
Collapse
|
16
|
Abstract
Microgliosis is an intense reaction of CNS microglia to pathogenic insults. One of the characteristic features of microgliosis is an increase in the number of activated microglia at the site of lesion. Ontogenically, microglia are considered to be of mesodermal lineage in the adult CNS, but the origin of the accumulated microglia in pathological conditions remains controversial. Some studies indicate that circulating cells from the bloodstream can infiltrate the CNS and contribute to microglial pool, but some studies suggest that local expansion of reactive microglia is the sole source for parenchymal microglia. Recent data suggest that latent progenitors may also exist in the CNS. Available evidence suggests that multiple sources of microglia may exist under various neurological conditions. In this review, we compare the prevalent views and supporting evidence from different experimental models and provide an overview on the origins of microgliosis.
Collapse
Affiliation(s)
- Ting Li
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Shengxiang Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou, China
| |
Collapse
|
17
|
Benakis C, Garcia-Bonilla L, Iadecola C, Anrather J. The role of microglia and myeloid immune cells in acute cerebral ischemia. Front Cell Neurosci 2015; 8:461. [PMID: 25642168 PMCID: PMC4294142 DOI: 10.3389/fncel.2014.00461] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 12/18/2014] [Indexed: 01/15/2023] Open
Abstract
The immune response to acute cerebral ischemia is a major contributor to stroke pathobiology. The inflammatory response is characterized by the participation of brain resident cells and peripheral leukocytes. Microglia in the brain and monocytes/neutrophils in the periphery have a prominent role in initiating, sustaining and resolving post-ischemic inflammation. In this review we aim to summarize recent literature concerning the origins, fate and role of microglia, monocytes and neutrophils in models of cerebral ischemia and to discuss their relevance for human stroke.
Collapse
Affiliation(s)
- Corinne Benakis
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Lidia Garcia-Bonilla
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| | - Josef Anrather
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College New York, NY, USA
| |
Collapse
|
18
|
Evans TA, Barkauskas DS, Myers JT, Huang AY. Intravital imaging of axonal interactions with microglia and macrophages in a mouse dorsal column crush injury. J Vis Exp 2014:e52228. [PMID: 25489963 PMCID: PMC4275021 DOI: 10.3791/52228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Traumatic spinal cord injury causes an inflammatory reaction involving blood-derived macrophages and central nervous system (CNS)-resident microglia. Intra-vital two-photon microscopy enables the study of macrophages and microglia in the spinal cord lesion in the living animal. This can be performed in adult animals with a traumatic injury to the dorsal column. Here, we describe methods for distinguishing macrophages from microglia in the CNS using an irradiation bone marrow chimera to obtain animals in which only macrophages or microglia are labeled with a genetically encoded green fluorescent protein. We also describe a injury model that crushes the dorsal column of the spinal cord, thereby producing a simple, easily accessible, rectangular lesion that is easily visualized in an animal through a laminectomy. Furthermore, we will outline procedures to sequentially image the animals at the anatomical site of injury for the study of cellular interactions during the first few days to weeks after injury.
Collapse
Affiliation(s)
- Teresa A Evans
- Department of Neurosciences, Case Western Reserve University
| | | | - Jay T Myers
- Department of Pediatrics, Case Western Reserve University
| | - Alex Y Huang
- Department of Pediatrics, Case Western Reserve University;
| |
Collapse
|
19
|
Selenica MLB, Alvarez JA, Nash KR, Lee DC, Cao C, Lin X, Reid P, Mouton PR, Morgan D, Gordon MN. Diverse activation of microglia by chemokine (C-C motif) ligand 2 overexpression in brain. J Neuroinflammation 2013; 10:86. [PMID: 23866683 PMCID: PMC3726363 DOI: 10.1186/1742-2094-10-86] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 06/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background The chemokine (C-C motif) ligand 2 (CCL2) is a monocyte chemoattractant protein that mediates macrophage recruitment and migration during peripheral and central nervous system (CNS) inflammation. Methods To determine the impact of CCL2 in inflammation in vivo and to elucidate the CCL2-induced polarization of activated brain microglia, we delivered CCL2 into the brains of wild-type mice via recombinant adeno-associated virus serotype 9 (rAAV-9) driven by the chicken β-actin promoter. We measured microglial activation using histological and chemical measurement and recruitment of monocytes using histology and flow cytometry. Results The overexpression of CCL2 in the CNS induced significant activation of brain resident microglia. CD45 and major histocompatibility complex class II immunoreactivity significantly increased at the sites of CCL2 administration. Histological characterization of the microglial phenotype revealed the elevation of “classically activated” microglial markers, such as calgranulin B and IL-1β, as well as markers associated with “alternative activation” of microglia, including YM1 and arginase 1. The protein expression profile in the hippocampus demonstrated markedly increased levels of IL-6, GM-CSF and eotaxin (CCL-11) in response to CCL2, but no changes in the levels of other cytokines, including TNF-α and IFN-γ. Moreover, real-time PCR analysis confirmed increases in mRNA levels of gene transcripts associated with neuroinflammation following CCL2 overexpression. Finally, we investigated the chemotactic properties of CCL2 in vivo by performing adoptive transfer of bone marrow–derived cells (BMDCs) isolated from donor mice that ubiquitously expressed green fluorescent protein. Flow cytometry and histological analyses indicated that BMDCs extravasated into brain parenchyma and colabeled with microglial markers. Conclusion Taken together, our results suggest that CCL2 strongly activates resident microglia in the brain. Both pro- and anti-inflammatory activation of microglia were prominent, with no bias toward the M1 or M2 phenotype in the activated cells. As expected, CCL2 overexpression actively recruited circulating monocytes into the CNS. Thus, CCL2 expression in mouse brain induces microglial activation and represents an efficient method for recruitment of peripheral macrophages.
Collapse
Affiliation(s)
- Maj-Linda B Selenica
- Department of Molecular Pharmacology & Physiology, Byrd Alzheimer Institute, University of South Florida, Tampa, FL, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
Neurological sequelae of human immunodeficiency virus (HIV) infection have been and remain a significant problem. Monocytes and macrophages in humans and monkeys are susceptible to infection by HIV and simian immunodeficiency virus (SIV), and are considered to be a main mechanism by which the central nervous system (CNS) is infected. Within the infected CNS, perivascular macrophages and, in some cases, parenchymal microglia are infected as are multinucleated giant cells when present. While neurons are not themselves directly infected, neuronal damage occurs within the infected CNS. Despite the success of antiretroviral therapy (ART) in limiting virus in plasma to non-detectable levels, neurological deficits persist. This review discusses the continued neurological dysfunctions that persist in the era of ART, focusing on the roles of monocyte and macrophage as targets of continued viral infection and as agents of pathogenesis in what appears to be emergent macrophage-mediated disease resulting from long-term HIV infection of the host. Data discussed include the biology of monocyte/macrophage activation with HIV and SIV infection, traffic of cells into and out of the CNS with infection, macrophage-associated biomarkers of CNS and cardiac disease, the role of antiretroviral therapy on these cells and CNS disease, as well as the need for effective adjunctive therapies targeting monocytes and macrophages.
Collapse
Affiliation(s)
- Tricia H. Burdo
- Department of Biology, Boston College, Chestnut Hill, MA, USA
| | - Andrew Lackner
- Tulane National Primate Research Center, Covington, LA, USA
| | | |
Collapse
|
21
|
Arnold T, Betsholtz C. Correction: The importance of microglia in the development of the vasculature in the central nervous system. Vasc Cell 2013; 5:12. [PMID: 23809768 PMCID: PMC3695819 DOI: 10.1186/2045-824x-5-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 12/12/2022] Open
Abstract
CORRECTION After the publication of this work 1 it was brought to our attention that citations in the article were not correspondingly numbered in the reference list. To avoid confusion, the article is republished here in its entirety, with the citations referenced correctly.The Publisher and authors apologize to the readers for the inconvenience caused. ABSTRACT The body's vascular system is thought to have developed in order to supply oxygen and nutrients to cells beyond the reach of simple diffusion. Hence, relative hypoxia in the growing central nervous system (CNS) is a major driving force for the ingression and refinement of the complex vascular bed that serves it. However, even before the establishment of this CNS vascular system, CNS-specific macrophages (microglia) migrate into the brain. Recent studies in mice point to the fundamental importance of microglia in shaping CNS vasculature during development, and re-shaping these vessels during pathological insults. In this review, we discuss the origin of CNS microglia and their localization within the brain based on data obtained in mice. We then review evidence supporting a functional role of these microglia in developmental angiogenesis. Although pathologic processes such as CNS ischemia may subvert the developmental functions of microglia/macrophages with significant effects on brain neo-angiogenesis, we have left this topic to other recent reviews 23.
Collapse
Affiliation(s)
- Tom Arnold
- Department of Medical Biochemistry and Biophysics, Division of Vascular Biology, Karolinska Institutet, Stockholm 17177, Sweden.
| | | |
Collapse
|
22
|
Hsieh CL, Kim CC, Ryba BE, Niemi EC, Bando JK, Locksley RM, Liu J, Nakamura MC, Seaman WE. Traumatic brain injury induces macrophage subsets in the brain. Eur J Immunol 2013; 43:2010-22. [PMID: 23630120 DOI: 10.1002/eji.201243084] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 04/08/2013] [Accepted: 04/24/2013] [Indexed: 12/20/2022]
Abstract
Traumatic brain injury (TBI) elicits innate inflammatory responses that can lead to secondary brain injury. To better understand the mechanisms involved in TBI-induced inflammation, we examined the nature of macrophages responding to TBI in mice. In this model, brain macrophages were increased >20-fold the day after injury and >77-fold 4 days after injury in the ipsilateral hemisphere compared with sham controls. TBI macrophage subsets were identified by using a reporter mouse strain (YARG) that expresses eYFP from an internal ribosome entry site (IRES) inserted at the 3' end of the gene for arginase-1 (Arg1), a hallmark of alternatively activated (M2) macrophages. One day after TBI, 21 ± 1.5% of ipsilateral brain macrophages expressed relatively high levels of Arg1 as detected by yellow fluorescent protein, and this subpopulation declined thereafter. Arg1(+) cells localized with macrophages near the TBI lesion. Gene expression analysis of sorted Arg1(+) and Arg1(-) brain macrophages revealed that both populations had profiles that included features of conventional M2 macrophages and classically activated (M1) macrophages. The Arg1(+) cells differed from Arg1(-) cells in multiple aspects, most notably in their chemokine repertoires. Thus, the macrophage response to TBI initially involves heterogeneous polarization toward at least two major subsets.
Collapse
|
23
|
Suh HS, Zhao ML, Derico L, Choi N, Lee SC. Insulin-like growth factor 1 and 2 (IGF1, IGF2) expression in human microglia: differential regulation by inflammatory mediators. J Neuroinflammation 2013; 10:37. [PMID: 23497056 PMCID: PMC3607995 DOI: 10.1186/1742-2094-10-37] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 01/03/2013] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Recent studies in experimental animals show that insulin-like growth factor 1 (IGF1) plays a trophic role during development and tissue injury and that microglia are important sources of IGF1. However, little information is available regarding the expression, regulation, and function of IGF1 and related proteins in human brain cells. In the current study, we examined the expression of IGF1 and IGF2 in human microglia in vivo and in vitro. METHODS Expression of IGF1 and IGF2 was examined by immunohistochemistry in post-mortem human brain sections derived from HIV+ and HIV- brains. In primary cultures of human fetal microglia, IGF1 and IGF2 mRNA and protein expression was examined by Q-PCR, ELISA, and Western blot analysis. Additionally, the role of IGF1 and IGF2 in neuroprotection was examined in primary human neuronal glial cultures. RESULTS Immunohistochemistry of human brain tissues showed that nonparenchymal cells (vessels and meninges), as well as parenchymal microglia and macrophages were positive for IGF1, in both HIV encephalitis and control brains, while IGF2 was undetectable. Cultured microglia expressed IGF1 mRNA and produced pg/ml levels of IGF1 protein; this was significantly suppressed by proinflammatory mediators, such as lipopolysaccharide (LPS), poly(I:C), and IFNγ. The Th2 cytokines IL-4 and IL-13 had no significant effect, but the cAMP analog (dibutyryl cAMP) significantly increased IGF1 production. In contrast, microglial IGF2 mRNA and protein (determined by Western blot) were upregulated by LPS. IGF1 receptor (IGF1R) immunoreactivity was predominantly expressed by neurons, and both IGF1 and IGF2 significantly protected neurons from cytokine (IL-1/IFNγ) induced death. CONCLUSIONS Our study in human brain tissues and cells indicates that microglia are important sources of neurotrophic growth factors IGF1 and IGF2, and that microglial activation phenotypes can influence the growth factor expression. Importantly, our results suggest that chronic neuroinflammation and upregulation of proinflammatory cytokines could lead to neurodegeneration by suppressing the production of microglia-derived neuronal growth factors, such as IGF1.
Collapse
Affiliation(s)
- Hyeon-Sook Suh
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | | | | | | | | |
Collapse
|
24
|
Arnold T, Betsholtz C. The importance of microglia in the development of the vasculature in the central nervous system. Vasc Cell 2013; 5:4. [PMID: 23422217 PMCID: PMC3583711 DOI: 10.1186/2045-824x-5-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 02/12/2013] [Indexed: 12/21/2022] Open
Abstract
The body’s vascular system is thought to have developed in order to supply oxygen and nutrients to cells beyond the reach of simple diffusion. Hence, relative hypoxia in the growing central nervous system (CNS) is a major driving force for the ingression and refinement of the complex vascular bed that serves it. However, even before the establishment of this CNS vascular system, CNS-specific macrophages (microglia) migrate into the brain. Recent studies in mice point to the fundamental importance of microglia in shaping CNS vasculature during development, and re-shaping these vessels during pathological insults. In this review, we discuss the origin of CNS microglia and their localization within the brain based on data obtained in mice. We then review evidence supporting a functional role of these microglia in developmental angiogenesis. Although pathologic processes such as CNS ischemia may subvert the developmental functions of microglia/macrophages with significant effects on brain neo-angiogenesis, we have left this topic to other recent reviews (Nat Rev Immunol 9:259–270, 2009 and Trends Mol Med 17:743–752, 2011).
Collapse
Affiliation(s)
- Tom Arnold
- Department of Medical Biochemistry and Biophysics, Division of Vascular Biology, Karolinska Institutet, 17177, Stockholm, Sweden.
| | | |
Collapse
|
25
|
Engineered stem cell-derived microglia as therapeutic vehicle for experimental autoimmune encephalomyelitis. Gene Ther 2013; 20:797-806. [DOI: 10.1038/gt.2012.100] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 01/07/2023]
|
26
|
Bellavance MA, Rivest S. The neuroendocrine control of the innate immune system in health and brain diseases. Immunol Rev 2012; 248:36-55. [PMID: 22725953 DOI: 10.1111/j.1600-065x.2012.01129.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The innate immune reaction takes place in the brain during immunogenic challenges, injury, and disease. Such a response is highly regulated by numerous anti-inflammatory mechanisms that may directly affect the ultimate consequences of such a reaction within the cerebral environment. The neuroendocrine control of this innate immune system by glucocorticoids is critical for the delicate balance between cell survival and damage in the presence of inflammatory mediators. Glucocorticoids play key roles in regulating the expression of inflammatory genes, and they also have the ability to modulate numerous functions that may ultimately lead to brain damage or repair after injury. Here we review these mechanisms and discuss data supporting both neuroprotective and detrimental roles of the neuroendocrine control of innate immunity.
Collapse
Affiliation(s)
- Marc-André Bellavance
- Laboratory of Endocrinology and Genomics, CHUQ Research Center and Department of Molecular Medicine, Faculty of Medicine, Laval University, Québec, Canada
| | | |
Collapse
|
27
|
The anatomical and cellular basis of immune surveillance in the central nervous system. Nat Rev Immunol 2012; 12:623-35. [DOI: 10.1038/nri3265] [Citation(s) in RCA: 669] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
28
|
Howe CL, Lafrance-Corey RG, Sundsbak RS, Sauer BM, Lafrance SJ, Buenz EJ, Schmalstieg WF. Hippocampal protection in mice with an attenuated inflammatory monocyte response to acute CNS picornavirus infection. Sci Rep 2012; 2:545. [PMID: 22848791 PMCID: PMC3408132 DOI: 10.1038/srep00545] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 06/28/2012] [Indexed: 12/24/2022] Open
Abstract
Neuronal injury during acute viral infection of the brain is associated with the development of persistent cognitive deficits and seizures in humans. In C57BL/6 mice acutely infected with the Theiler's murine encephalomyelitis virus, hippocampal CA1 neurons are injured by a rapid innate immune response, resulting in profound memory deficits. In contrast, infected SJL and B6xSJL F1 hybrid mice exhibit essentially complete hippocampal and memory preservation. Analysis of brain-infiltrating leukocytes revealed that SJL mice mount a sharply attenuated inflammatory monocyte response as compared to B6 mice. Bone marrow transplantation experiments isolated the attenuation to the SJL immune system. Adoptive transfer of B6 inflammatory monocytes into acutely infected B6xSJL hosts converted these mice to a hippocampal damage phenotype and induced a cognitive deficit marked by failure to recognize a novel object. These findings show that inflammatory monocytes are the critical cellular mediator of hippocampal injury during acute picornavirus infection of the brain.
Collapse
Affiliation(s)
- Charles L Howe
- Department of Neurology, College ofMedicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
| | | | | | | | | | | | | |
Collapse
|
29
|
Doyle KP, Buckwalter MS. The double-edged sword of inflammation after stroke: What sharpens each edge? Ann Neurol 2012; 71:729-31. [DOI: 10.1002/ana.23579] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|