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Lannes N, Eppler E, Etemad S, Yotovski P, Filgueira L. Microglia at center stage: a comprehensive review about the versatile and unique residential macrophages of the central nervous system. Oncotarget 2017; 8:114393-114413. [PMID: 29371994 PMCID: PMC5768411 DOI: 10.18632/oncotarget.23106] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 11/15/2017] [Indexed: 02/07/2023] Open
Abstract
Microglia cells are the unique residential macrophages of the central nervous system (CNS). They have a special origin, as they derive from the embryonic yolk sac and enter the developing CNS at a very early stage. They play an important role during CNS development and adult homeostasis. They have a major contribution to adult neurogenesis and neuroinflammation. Thus, they participate in the pathogenesis of neurodegenerative diseases and contribute to aging. They play an important role in sustaining and breaking the blood-brain barrier. As innate immune cells, they contribute substantially to the immune response against infectious agents affecting the CNS. They play also a major role in the growth of tumours of the CNS. Microglia are consequently the key cell population linking the nervous and the immune system. This review covers all different aspects of microglia biology and pathology in a comprehensive way.
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Affiliation(s)
- Nils Lannes
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Elisabeth Eppler
- Pestalozzistrasse Zo, Department of BioMedicine, University of Basel, CH-4056 Basel, Switzerland
| | - Samar Etemad
- Building 71/218 RBWH Herston, Centre for Clinical Research, The University of Queensland, QLD 4029 Brisbane, Australia
| | - Peter Yotovski
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
| | - Luis Filgueira
- Albert Gockel, Anatomy, Department of Medicine, University of Fribourg, CH-1700 Fribourg, Switzerland
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Oxidative stress and DNA damage after cerebral ischemia: Potential therapeutic targets to repair the genome and improve stroke recovery. Neuropharmacology 2017; 134:208-217. [PMID: 29128308 DOI: 10.1016/j.neuropharm.2017.11.011] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/02/2017] [Accepted: 11/05/2017] [Indexed: 12/12/2022]
Abstract
The past two decades have witnessed remarkable advances in oxidative stress research, particularly in the context of ischemic brain injury. Oxidative stress in ischemic tissues compromises the integrity of the genome, resulting in DNA lesions, cell death in neurons, glial cells, and vascular cells, and impairments in neurological recovery after stroke. As DNA is particularly vulnerable to oxidative attack, cells have evolved the ability to induce multiple DNA repair mechanisms, including base excision repair (BER), nucleotide excision repair (NER) and non-homogenous endpoint jointing (NHEJ). Defective DNA repair is tightly correlated with worse neurological outcomes after stroke, whereas upregulation of DNA repair enzymes, such as APE1, OGG1, and XRCC1, improves long-term functional recovery following stroke. Indeed, DNA damage and repair are now known to play critical roles in fundamental aspects of stroke recovery, such as neurogenesis, white matter recovery, and neurovascular unit remodeling. Several DNA repair enzymes are essential for comprehensive neural repair mechanisms after stroke, including Polβ and NEIL3 for neurogenesis, APE1 for white matter repair, Gadd45b for axonal regeneration, and DNA-PKs for neurovascular remodeling. This review discusses the emerging role of DNA damage and repair in functional recovery after stroke and highlights the contribution of DNA repair to regenerative elements after stroke. This article is part of the Special Issue entitled 'Cerebral Ischemia'.
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Splitting the "Unsplittable": Dissecting Resident and Infiltrating Macrophages in Experimental Autoimmune Encephalomyelitis. Int J Mol Sci 2017; 18:ijms18102072. [PMID: 28961183 PMCID: PMC5666754 DOI: 10.3390/ijms18102072] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 09/23/2017] [Accepted: 09/25/2017] [Indexed: 12/12/2022] Open
Abstract
Macrophages predominate the inflammatory landscape within multiple sclerosis (MS) lesions, not only regarding cellularity but also with respect to the diverse functions this cell fraction provides during disease progression and remission. Researchers have been well aware of the fact that the macrophage pool during central nervous system (CNS) autoimmunity consists of a mixture of myeloid cells. Yet, separating these populations to define their unique contribution to disease pathology has long been challenging due to their similar marker expression. Sophisticated lineage tracing approaches as well as comprehensive transcriptome analysis have elevated our insight into macrophage biology to a new level enabling scientists to dissect the roles of resident (microglia and non-parenchymal macrophages) and infiltrating macrophages with unprecedented precision. To do so in an accurate way, researchers have to know their toolbox, which has been filled with diverse, discriminating approaches from decades of studying neuroinflammation in animal models. Every method has its own strengths and weaknesses, which will be addressed in this review. The focus will be on tools to manipulate and/or identify different macrophage subgroups within the injured murine CNS.
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E Hirbec H, Noristani HN, Perrin FE. Microglia Responses in Acute and Chronic Neurological Diseases: What Microglia-Specific Transcriptomic Studies Taught (and did Not Teach) Us. Front Aging Neurosci 2017; 9:227. [PMID: 28785215 PMCID: PMC5519576 DOI: 10.3389/fnagi.2017.00227] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Over the last decade, microglia have been acknowledged to be key players in central nervous system (CNS) under both physiological and pathological conditions. They constantly survey the CNS environment and as immune cells, in pathological contexts, they provide the first host defense and orchestrate the immune response. It is well recognized that under pathological conditions microglia have both sequential and simultaneous, beneficial and detrimental effects. Cell-specific transcriptomics recently became popular in Neuroscience field allowing concurrent monitoring of the expression of numerous genes in a given cell population. Moreover, by comparing two or more conditions, these approaches permit to unbiasedly identify deregulated genes and pathways. A growing number of studies have thus investigated microglial transcriptome remodeling over the course of neuropathological conditions and highlighted the molecular diversity of microglial response to different diseases. In the present work, we restrict our review to microglia obtained directly from in vivo samples and not cell culture, and to studies using whole-genome strategies. We first critically review the different methods developed to decipher microglia transcriptome. In particular, we compare advantages and drawbacks of flow cytometry and laser microdissection to isolate pure microglia population as well as identification of deregulated microglial genes obtained via RNA sequencing (RNA-Seq) vs. microarrays approaches. Second, we summarize insights obtained from microglia transcriptomes in traumatic brain and spinal cord injuries, pain and more chronic neurological conditions including Amyotrophic lateral sclerosis (ALS), Alzheimer disease (AD) and Multiple sclerosis (MS). Transcriptomic responses of microglia in other non-neurodegenerative CNS disorders such as gliomas and sepsis are also addressed. Third, we present a comparison of the most activated pathways in each neuropathological condition using Gene ontology (GO) classification and highlight the diversity of microglia response to insults focusing on their pro- and anti-inflammatory signatures. Finally, we discuss the potential of the latest technological advances, in particular, single cell RNA-Seq to unravel the individual microglial response diversity in neuropathological contexts.
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Affiliation(s)
- Hélène E Hirbec
- Institute for Functional Genomics, CNRS UMR5203, INSERM U1191, University of MontpellierMontpellier, France.,Laboratory of Excellence in Ion Channel Science and Therapeutics (LabEx ICST)Montpellier, France
| | - Harun N Noristani
- University of Montpellier, INSERM U1198Montpellier, France.,École Pratique des Hautes Études (EPHE)Paris, France
| | - Florence E Perrin
- University of Montpellier, INSERM U1198Montpellier, France.,École Pratique des Hautes Études (EPHE)Paris, France
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55
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Noristani HN, Boukhaddaoui H, Saint-Martin G, Auzer P, Sidiboulenouar R, Lonjon N, Alibert E, Tricaud N, Goze-Bac C, Coillot C, Perrin FE. A Combination of Ex vivo Diffusion MRI and Multiphoton to Study Microglia/Monocytes Alterations after Spinal Cord Injury. Front Aging Neurosci 2017; 9:230. [PMID: 28769787 PMCID: PMC5515855 DOI: 10.3389/fnagi.2017.00230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Central nervous system (CNS) injury has been observed to lead to microglia activation and monocytes infiltration at the lesion site. Ex vivo diffusion magnetic resonance imaging (diffusion MRI or DWI) allows detailed examination of CNS tissues, and recent advances in clearing procedures allow detailed imaging of fluorescent-labeled cells at high resolution. No study has yet combined ex vivo diffusion MRI and clearing procedures to establish a possible link between microglia/monocytes response and diffusion coefficient in the context of spinal cord injury (SCI). We carried out ex vivo MRI of the spinal cord at different time-points after spinal cord transection followed by tetrahydrofuran based clearing and examined the density and morphology of microglia/monocytes using two-photon microscopy. Quantitative analysis revealed an early marked increase in microglial/monocytes density that is associated with an increase in the extension of the lesion measured using diffusion MRI. Morphological examination of microglia/monocytes somata at the lesion site revealed a significant increase in their surface area and volume as early as 72 hours post-injury. Time-course analysis showed differential microglial/monocytes response rostral and caudal to the lesion site. Microglia/monocytes showed a decrease in reactivity over time caudal to the lesion site, but an increase was observed rostrally. Direct comparison of microglia/monocytes morphology, obtained through multiphoton, and the longitudinal apparent diffusion coefficient (ADC), measured with diffusion MRI, highlighted that axonal integrity does not correlate with the density of microglia/monocytes or their somata morphology. We emphasize that differential microglial/monocytes reactivity rostral and caudal to the lesion site may thus coincide, at least partially, with reported temporal differences in debris clearance. Our study demonstrates that the combination of ex vivo diffusion MRI and two-photon microscopy may be used to follow structural tissue alteration. Lesion extension coincides with microglia/monocytes density; however, a direct relationship between ADC and microglia/monocytes density and morphology was not observed. We highlighted a differential rostro-caudal microglia/monocytes reactivity that may correspond to a temporal difference in debris clearance and axonal integrity. Thus, potential therapeutic strategies targeting microglia/monocytes after SCI may need to be adjusted not only with the time after injury but also relative to the location to the lesion site.
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Affiliation(s)
- Harun N Noristani
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France.,University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France
| | - Hassan Boukhaddaoui
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Guillaume Saint-Martin
- University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France.,Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Pauline Auzer
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Rahima Sidiboulenouar
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Nicolas Lonjon
- University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France.,Centre Hospitalier Universitaire de Montpellier (CHRU), Gui de Chauliac HospitalMontpellier, France
| | - Eric Alibert
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Nicolas Tricaud
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Christophe Goze-Bac
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Christophe Coillot
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Florence E Perrin
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France.,University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France
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