51
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Zhang J, Zhang L, Yi S, Jiang X, Qiao Y, Zhang Y, Xiao C, Zhou T. Mouse Astrocytes Promote Microglial Ramification by Releasing TGF-β and Forming Glial Fibers. Front Cell Neurosci 2020; 14:195. [PMID: 32754014 PMCID: PMC7366495 DOI: 10.3389/fncel.2020.00195] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/05/2020] [Indexed: 12/13/2022] Open
Abstract
The morphology of microglial cells is often closely related to their functions. The mechanisms that regulate microglial ramification are not well understood. Here we reveal the biological mechanisms by which astrocytes regulate microglial ramification. Morphological variation in mouse microglial cultures was measured in terms of cell area as well as branch number and length. Effects on microglial ramification were analyzed after microinjecting the toxin L-alpha-aminoadipic acid (L-AAA) in the mouse cortex or hippocampus to ablate astrocytes, and after culturing microglia on their own in an astrocyte-conditioned medium (ACM) or together with astrocytes in coculture. TGF-β expression was determined by Western blotting, immunohistochemistry, and ELISA. The TGF-β signaling pathway was blocked by the TGF-β antibody to assess the role of TGF-β on microglial ramification. The results showed that microglia had more and longer branches and smaller cell bodies in brain areas where astrocytes were abundant. In the mouse cortex and hippocampus, ablation of astrocytes by L-AAA decreased number and length of microglial branches and increased the size of cell bodies. Similar results were obtained with isolated microglia in culture. However, isolated microglia were able to maintain their multibranched structure for a long time when cultured on astrocyte monolayers. Ameboid microglia isolated from P0 to P3 mice showed increased ramification when cultured in ACM or on astrocyte monolayers. Microglia cultured on astrocyte monolayers showed more complex branching structures than those cultured in ACM. Blocking astrocyte-derived TGF-β decreased microglial ramification. Astrocytes induced the formation of protuberances on branches of microglia by forming glial fibers that increased traction. These experiments in mice suggest that astrocytes promote microglial ramification by forming glial fibers to create traction and by secreting soluble factors into the surroundings. For example, astrocyte-secreted TGF-β promotes microglia to generate primitive branches, whose ramification is refined by glial fibers.
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Affiliation(s)
- Jinqiang Zhang
- Resource Institute for Chinese & Ethnic Materia Medica, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Lijuan Zhang
- School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Saini Yi
- Resource Institute for Chinese & Ethnic Materia Medica, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Xue Jiang
- Resource Institute for Chinese & Ethnic Materia Medica, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Yan Qiao
- Institute of Medical Biology Science, Chinese Academy of Medical Science, Beijing, China
| | - Yue Zhang
- School of Life Science and Technology, Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, China
| | - Chenghong Xiao
- Resource Institute for Chinese & Ethnic Materia Medica, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Tao Zhou
- Resource Institute for Chinese & Ethnic Materia Medica, Guizhou University of Traditional Chinese Medicine, Guiyang, China
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52
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Sos KE, Mayer MI, Takács VT, Major A, Bardóczi Z, Beres BM, Szeles T, Saito T, Saido TC, Mody I, Freund TF, Nyiri G. Amyloid β induces interneuron-specific changes in the hippocampus of APPNL-F mice. PLoS One 2020; 15:e0233700. [PMID: 32469963 PMCID: PMC7259556 DOI: 10.1371/journal.pone.0233700] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/11/2020] [Indexed: 01/07/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and amyloid-beta (Aβ) depositions generated by the proteolysis of amyloid precursor protein (APP) in the brain. In APPNL-F mice, APP gene was humanized and contains two familial AD mutations, and APP-unlike other mouse models of AD-is driven by the endogenous mouse APP promoter. Similar to people without apparent cognitive dysfunction but with heavy Aβ plaque load, we found no significant decline in the working memory of adult APPNL-F mice, but these mice showed decline in the expression of normal anxiety. Using immunohistochemistry and 3D block-face scanning electron microscopy, we found no changes in GABAA receptor positivity and size of somatic and dendritic synapses of hippocampal interneurons. We did not find alterations in the level of expression of perineuronal nets around parvalbumin (PV) interneurons or in the density of PV- or somatostatin-positive hippocampal interneurons. However, in contrast to other investigated cell types, PV interneuron axons were occasionally mildly dystrophic around Aβ plaques, and the synapses of PV-positive axon initial segment (AIS)-targeting interneurons were significantly enlarged. Our results suggest that PV interneurons are highly resistant to amyloidosis in APPNL-F mice and amyloid-induced increase in hippocampal pyramidal cell excitability may be compensated by PV-positive AIS-targeting cells. Mechanisms that make PV neurons more resilient could therefore be exploited in the treatment of AD for mitigating Aβ-related inflammatory effects on neurons.
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Affiliation(s)
- Katalin E. Sos
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Márton I. Mayer
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Virág T. Takács
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Abel Major
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Zsuzsanna Bardóczi
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Barnabas M. Beres
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Tamás Szeles
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN, Center for Brain Science, Saitama, Japan
- Department of Neurocognitive Science, Nagoya City University Graduate School of Medical Science, Aichi, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN, Center for Brain Science, Saitama, Japan
| | - István Mody
- Department of Neurology, University of California, Los Angeles, California, United States of America
| | - Tamás F. Freund
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Gábor Nyiri
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
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53
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Carvalho K, Faivre E, Pietrowski MJ, Marques X, Gomez-Murcia V, Deleau A, Huin V, Hansen JN, Kozlov S, Danis C, Temido-Ferreira M, Coelho JE, Mériaux C, Eddarkaoui S, Gras SL, Dumoulin M, Cellai L, Landrieu I, Chern Y, Hamdane M, Buée L, Boutillier AL, Levi S, Halle A, Lopes LV, Blum D. Exacerbation of C1q dysregulation, synaptic loss and memory deficits in tau pathology linked to neuronal adenosine A2A receptor. Brain 2020; 142:3636-3654. [PMID: 31599329 PMCID: PMC6821333 DOI: 10.1093/brain/awz288] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/14/2022] Open
Abstract
Accumulating data support the role of tau pathology in cognitive decline in ageing and Alzheimer’s disease, but underlying mechanisms remain ill-defined. Interestingly, ageing and Alzheimer’s disease have been associated with an abnormal upregulation of adenosine A2A receptor (A2AR), a fine tuner of synaptic plasticity. However, the link between A2AR signalling and tau pathology has remained largely unexplored. In the present study, we report for the first time a significant upregulation of A2AR in patients suffering from frontotemporal lobar degeneration with the MAPT P301L mutation. To model these alterations, we induced neuronal A2AR upregulation in a tauopathy mouse model (THY-Tau22) using a new conditional strain allowing forebrain overexpression of the receptor. We found that neuronal A2AR upregulation increases tau hyperphosphorylation, potentiating the onset of tau-induced memory deficits. This detrimental effect was linked to a singular microglial signature as revealed by RNA sequencing analysis. In particular, we found that A2AR overexpression in THY-Tau22 mice led to the hippocampal upregulation of C1q complement protein—also observed in patients with frontotemporal lobar degeneration—and correlated with the loss of glutamatergic synapses, likely underlying the observed memory deficits. These data reveal a key impact of overactive neuronal A2AR in the onset of synaptic loss in tauopathies, paving the way for new therapeutic approaches.
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Affiliation(s)
- Kevin Carvalho
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Emilie Faivre
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | | | - Xavier Marques
- Institut du Fer à Moulin, Inserm UMR-S 1270, Sorbonne Université, F, Paris, France
| | - Victoria Gomez-Murcia
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Aude Deleau
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Vincent Huin
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Jan N Hansen
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Stanislav Kozlov
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Clément Danis
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France.,University of Lille, CNRS UMR8576, Unité de Glycobiologie Structurale et Fonctionnelle, LabEx DISTALZ, Lille, F Lille, France
| | - Mariana Temido-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisbon, Portugal
| | - Joana E Coelho
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisbon, Portugal
| | - Céline Mériaux
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Sabiha Eddarkaoui
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Stéphanie Le Gras
- CNRS, Inserm, UMR 7104, GenomEast Platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg, F Illkirch, France
| | | | - Lucrezia Cellai
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | | | - Isabelle Landrieu
- University of Lille, CNRS UMR8576, Unité de Glycobiologie Structurale et Fonctionnelle, LabEx DISTALZ, Lille, F Lille, France
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Malika Hamdane
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Luc Buée
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
| | - Anne-Laurence Boutillier
- Laboratoire de Neuroscience Cognitives et Adaptatives (LNCA), CNRS UMR 7364, Université de Strasbourg, F Strasbourg, France
| | - Sabine Levi
- Institut du Fer à Moulin, Inserm UMR-S 1270, Sorbonne Université, F, Paris, France
| | - Annett Halle
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Luisa V Lopes
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisbon, Portugal
| | - David Blum
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - JPArc, LabEx DISTALZ, F Lille, France
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54
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Vay SU, Flitsch LJ, Rabenstein M, Monière H, Jakovcevski I, Andjus P, Bijelic D, Blaschke S, Walter HL, Fink GR, Schroeter M, Rueger MA. The impact of hyperpolarization-activated cyclic nucleotide-gated (HCN) and voltage-gated potassium KCNQ/Kv7 channels on primary microglia function. J Neuroinflammation 2020; 17:100. [PMID: 32248813 PMCID: PMC7132998 DOI: 10.1186/s12974-020-01779-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/18/2020] [Indexed: 01/03/2023] Open
Abstract
Background Microglia are essential to maintain cell homeostasis in the healthy brain and are activated after brain injury. Upon activation, microglia polarize towards different phenotypes. The course of microglia activation is complex and depends on signals in the surrounding milieu. Recently, it has been suggested that microglia respond to ion currents, as a way of regulating their activity and function. Methods and results Under the hypothesis that HCN and KCNQ/Kv7 channels impact on microglia, we studied primary rat microglia in the presence or absence of specific pharmacological blockade or RNA silencing. Primary microglia expressed the subunits HCN1-4, Kv7.2, Kv7.3, and Kv7.5. The expression of HCN2, as well as Kv7.2 and Kv7.3, varied among different microglia phenotypes. The pharmacological blockade of HCN channels by ZD7288 resulted in cell depolarization with slowly rising intracellular calcium levels, leading to enhanced survival and reduced proliferation rates of resting microglia. Furthermore, ZD7288 treatment, as well as knockdown of HCN2 RNA by small interfering RNA, resulted in an attenuation of later microglia activation—both towards the anti- and pro-inflammatory phenotype. However, HCN channel inhibition enhanced the phagocytic capacity of IL4-stimulated microglia. Blockade of Kv7/KCNQ channel by XE-991 exclusively inhibited the migratory capacity of resting microglia. Conclusion These observations suggest that the HCN current contributes to various microglia functions and impacts on the course of microglia activation, while the Kv7/KCNQ channels affect microglia migration. Characterizing the role of HCN channels in microglial functioning may offer new therapeutic approaches for targeted modulation of neuroinflammation as a hallmark of various neurological disorders.
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Affiliation(s)
- Sabine Ulrike Vay
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.
| | - Lea Jessica Flitsch
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany
| | - Monika Rabenstein
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany
| | - Helena Monière
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany
| | - Igor Jakovcevski
- Institute for Molecular and Behavioural Neuroscience and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Pavle Andjus
- Center for Laser Microscopy-CLM, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Dunja Bijelic
- Center for Laser Microscopy-CLM, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Stefan Blaschke
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Helene Luise Walter
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany
| | - Gereon Rudolf Fink
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Michael Schroeter
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
| | - Maria Adele Rueger
- Department of Neurology, Faculty of Medicine and University Hospital, University Hospital of Cologne, Kerpener Strasse 62, 50924, Cologne, Germany.,Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Juelich, Germany
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55
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Werner Y, Mass E, Ashok Kumar P, Ulas T, Händler K, Horne A, Klee K, Lupp A, Schütz D, Saaber F, Redecker C, Schultze JL, Geissmann F, Stumm R. Cxcr4 distinguishes HSC-derived monocytes from microglia and reveals monocyte immune responses to experimental stroke. Nat Neurosci 2020; 23:351-362. [PMID: 32042176 PMCID: PMC7523735 DOI: 10.1038/s41593-020-0585-y] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/02/2020] [Indexed: 12/26/2022]
Abstract
Monocyte-derived and tissue-resident macrophages are ontogenetically distinct components of the innate immune system. Assessment of their respective functions in pathology is complicated by changes to the macrophage phenotype during inflammation. Here we find that Cxcr4-CreER enables permanent genetic labeling of hematopoietic stem cells (HSCs) and distinguishes HSC-derived monocytes from microglia and other tissue-resident macrophages. By combining Cxcr4-CreER-mediated lineage tracing with Cxcr4 inhibition or conditional Cxcr4 ablation in photothrombotic stroke, we find that Cxcr4 promotes initial monocyte infiltration and subsequent territorial restriction of monocyte-derived macrophages to infarct tissue. After transient focal ischemia, Cxcr4 deficiency reduces monocyte infiltration and blunts the expression of pattern recognition and defense response genes in monocyte-derived macrophages. This is associated with an altered microglial response and deteriorated outcomes. Thus, Cxcr4 is essential for an innate-immune-system-mediated defense response after cerebral ischemia. We further propose Cxcr4-CreER as a universal tool to study functions of HSC-derived cells.
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Affiliation(s)
- Yves Werner
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Elvira Mass
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Developmental Biology of the Immune System, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany.
| | - Praveen Ashok Kumar
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Thomas Ulas
- Genomics and Immunoregulation, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
- PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases and University of Bonn, Bonn, Germany
| | - Kristian Händler
- Genomics and Immunoregulation, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
- PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases and University of Bonn, Bonn, Germany
| | - Arik Horne
- Genomics and Immunoregulation, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Kathrin Klee
- Genomics and Immunoregulation, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Dagmar Schütz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Friederike Saaber
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | | | - Joachim L Schultze
- Genomics and Immunoregulation, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
- PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases and University of Bonn, Bonn, Germany
| | - Frederic Geissmann
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Ralf Stumm
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany.
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56
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Hashemiaghdam A, Mroczek M. Microglia heterogeneity and neurodegeneration: The emerging paradigm of the role of immunity in Alzheimer's disease. J Neuroimmunol 2020; 341:577185. [PMID: 32045774 DOI: 10.1016/j.jneuroim.2020.577185] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 02/01/2020] [Accepted: 02/01/2020] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is the most common dementia type affecting nearly 44 million people worldwide. Recent findings point to microglia as a significant contributor to neural development, neuroinflammation, and degeneration. Dysregulated immunoactivity in AD has been broadly studied, and current research on animal models enabled us to identify a new cluster of microglia (disease-associated microglia) alongside previously detected glial populations (e.g., plaque-associated microglia, dark microglia, Human Alzheimer's microglia) associated with neuroinflammation and with macrophagic activity. These distinct populations of glia show a spatial distribution within plaques with unique imaging features and distinct gene expression profile. Novel genetic approaches using single-nuclei RNA sequencing (sn-RNA seq) allowed researchers to identify gene expression profiles from fixed human samples. Recent studies, exposing transcriptomic clusters of disease-related cells and analyzing sequenced RNA from sorted myeloid cells, seem to confirm the hypothesis of the central role of glia in the pathogenesis of Alzheimer's disease. These discoveries may shed light on the effects of microglial activation and differences in gene expression profiles, furthering research towards the development of a cell-specific therapy. In this review, we examine recent studies that guide us towards recognizing the role of diverse populations of glial cells and their possible heterogeneous functional states in the pathogenesis of AD in humans.
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Affiliation(s)
| | - Magdalena Mroczek
- The John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
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57
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Klaus C, Hansen JN, Ginolhac A, Gérard D, Gnanapragassam VS, Horstkorte R, Rossdam C, Buettner FFR, Sauter T, Sinkkonen L, Neumann H, Linnartz-Gerlach B. Reduced sialylation triggers homeostatic synapse and neuronal loss in middle-aged mice. Neurobiol Aging 2020; 88:91-107. [PMID: 32087947 DOI: 10.1016/j.neurobiolaging.2020.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 12/21/2022]
Abstract
Sialic acid-binding Ig-like lectin (Siglec) receptors are linked to neurodegenerative processes, but the role of sialic acids in physiological aging is still not fully understood. We investigated the impact of reduced sialylation in the brain of mice heterozygous for the enzyme glucosamine-2-epimerase/N-acetylmannosamine kinase (GNE+/-) that is essential for sialic acid biosynthesis. We demonstrate that GNE+/- mice have hyposialylation in different brain regions, less synapses in the hippocampus and reduced microglial arborization already at 6 months followed by increased loss of neurons at 12 months. A transcriptomic analysis revealed no pro-inflammatory changes indicating an innate homeostatic immune process leading to the removal of synapses and neurons in GNE+/- mice during aging. Crossbreeding with complement C3-deficient mice rescued the earlier onset of neuronal and synaptic loss as well as the changes in microglial arborization. Thus, sialic acids of the glycocalyx contribute to brain homeostasis and act as a recognition system for the innate immune system in the brain.
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Affiliation(s)
- Christine Klaus
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jan N Hansen
- Biophysical Imaging, Institute of Innate Immunity, Medical Faculty, University of Bonn, Bonn, Germany
| | - Aurélien Ginolhac
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Deborah Gérard
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Vinayaga S Gnanapragassam
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Rüdiger Horstkorte
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Charlotte Rossdam
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Falk F R Buettner
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Thomas Sauter
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Lasse Sinkkonen
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany.
| | - Bettina Linnartz-Gerlach
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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58
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Peña-Ortega F. Brain Arrhythmias Induced by Amyloid Beta and Inflammation: Involvement in Alzheimer’s Disease and Other Inflammation-related Pathologies. Curr Alzheimer Res 2020; 16:1108-1131. [DOI: 10.2174/1567205017666191213162233] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 10/29/2019] [Accepted: 11/05/2019] [Indexed: 12/13/2022]
Abstract
A variety of neurological diseases, including Alzheimer’s disease (AD), involve amyloid beta (Aβ) accumulation and/or neuroinflammation, which can alter synaptic and neural circuit functions. Consequently, these pathological conditions induce changes in neural network rhythmic activity (brain arrhythmias), which affects many brain functions. Neural network rhythms are involved in information processing, storage and retrieval, which are essential for memory consolidation, executive functioning and sensory processing. Therefore, brain arrhythmias could have catastrophic effects on circuit function, underlying the symptoms of various neurological diseases. Moreover, brain arrhythmias can serve as biomarkers for a variety of brain diseases. The aim of this review is to provide evidence linking Aβ and inflammation to neural network dysfunction, focusing on alterations in brain rhythms and their impact on cognition and sensory processing. I reviewed the most common brain arrhythmias characterized in AD, in AD transgenic models and those induced by Aβ. In addition, I reviewed the modulations of brain rhythms in neuroinflammatory diseases and those induced by immunogens, interleukins and microglia. This review reveals that Aβ and inflammation produce a complex set of effects on neural network function, which are related to the induction of brain arrhythmias and hyperexcitability, both closely related to behavioral alterations. Understanding these brain arrhythmias can help to develop therapeutic strategies to halt or prevent these neural network alterations and treat not only the arrhythmias but also the symptoms of AD and other inflammation-related pathologies.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiologia del Desarrollo y Neurofisiologia, Instituto de Neurobiologia, Universidad Nacional Autonoma de Mexico, Queretaro, Qro., 76230, Mexico
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Franco-Bocanegra DK, George B, Lau LC, Holmes C, Nicoll JAR, Boche D. Microglial motility in Alzheimer's disease and after Aβ42 immunotherapy: a human post-mortem study. Acta Neuropathol Commun 2019; 7:174. [PMID: 31703599 PMCID: PMC6842157 DOI: 10.1186/s40478-019-0828-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/13/2019] [Indexed: 02/04/2023] Open
Abstract
Microglial function is highly dependent on cell motility, with baseline motility required for homeostatic surveillance activity and directed motility to migrate towards a source of injury. Experimental evidence suggests impaired microglial motility in Alzheimer’s disease (AD) and therefore we have investigated whether the expression of proteins associated with motility is altered in AD and affected by the Aβ immunotherapy using post-mortem brain tissue of 32 controls, 44 AD cases, and 16 AD cases from our unique group of patients immunised against Aβ42 (iAD). Sections of brain were immunolabelled and quantified for (i) the motility-related microglial proteins Iba1, cofilin 1 (CFL1), coronin-1a (CORO1A) and P2RY12, and (ii) pan-Aβ, Aβ42 and phosphorylated tau (ptau). The neuroinflammatory environment was characterised using Meso Scale Discovery multiplex assays. The expression of all four motility-related proteins was unmodified in AD compared with controls, whereas Iba1 and P2RY12, the homeostatic markers, were increased in the iAD group compared with AD. Iba1 and P2RY12 showed significant positive correlations with Aβ in controls but not in the AD or iAD groups. Pro- and anti-inflammatory proteins were increased in AD, whereas immunotherapy appears to result in a slightly less pro-inflammatory environment. Our findings suggest that as Aβ appears during the ageing process, the homeostatic Iba1 and P2RY12 –positive microglia respond to Aβ, but this response is absent in AD. Aβ-immunisation promoted increased Iba1 and P2RY12 expression, likely reflecting increased baseline microglial motility but without restoring the profile observed in controls.
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60
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Moore Z, Taylor JM, Crack PJ. The involvement of microglia in Alzheimer's disease: a new dog in the fight. Br J Pharmacol 2019; 176:3533-3543. [PMID: 30445661 PMCID: PMC6715787 DOI: 10.1111/bph.14546] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/17/2018] [Accepted: 10/29/2018] [Indexed: 12/15/2022] Open
Abstract
First described clinically in 1906, Alzheimer's disease (AD) is the most common neurodegenerative disease and form of dementia worldwide. Despite its prevalence, only five therapies are currently approved for AD, all dealing with the symptoms rather than the underlying causes of the disease. A multitude of experimental evidence has suggested that the once thought inconsequential process of neuroinflammation does, in fact, contribute to the AD pathogenesis. One such CNS cell type critical to this process are microglia. Plastic in nature with varied roles, microglia are emerging as key contributors to AD pathology. This review will focus on the role of microglia in the neuroinflammatory response in AD, highlighting recent studies implicating aberrant changes in microglial function in disease progression. Of critical note is that with these advances, a reconceptualization of the framework in which we view microglia is required. LINKED ARTICLES: This article is part of a themed section on Therapeutics for Dementia and Alzheimer's Disease: New Directions for Precision Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.18/issuetoc.
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Affiliation(s)
- Zachery Moore
- Neuropharmacology Laboratory, Department of Pharmacology and TherapeuticsUniversity of MelbourneMelbourneVICAustralia
| | - Juliet M Taylor
- Neuropharmacology Laboratory, Department of Pharmacology and TherapeuticsUniversity of MelbourneMelbourneVICAustralia
| | - Peter J Crack
- Neuropharmacology Laboratory, Department of Pharmacology and TherapeuticsUniversity of MelbourneMelbourneVICAustralia
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61
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Sun Y, Huang Y, Chen WW, Jia J, Wei T. Letter to the Editor concerning "Influence of microglia and astrocyte activation in the neuroinflammatory pathogenesis of Alzheimer's disease: Rational insights for the therapeutic approaches". J Clin Neurosci 2019; 68:354. [PMID: 31351703 DOI: 10.1016/j.jocn.2019.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/06/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Yuan Sun
- Department of Neurology, Xuzhou Central Hospital, Xuzhou, China
| | - Ying Huang
- Department of Neurology, Xuzhou Central Hospital, Xuzhou, China
| | - Wei-Wei Chen
- Department of Neurology, Xuzhou Central Hospital, Xuzhou, China
| | - Juan Jia
- Department of Neurology, Xuzhou Central Hospital, Xuzhou, China
| | - Tao Wei
- Department of Neurology, Xuzhou Central Hospital, Xuzhou, China.
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62
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Schmöle AC, Lundt R, Toporowski G, Hansen JN, Beins E, Halle A, Zimmer A. Cannabinoid Receptor 2-Deficiency Ameliorates Disease Symptoms in a Mouse Model with Alzheimer's Disease-Like Pathology. J Alzheimers Dis 2019; 64:379-392. [PMID: 29865078 DOI: 10.3233/jad-180230] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
It is widely accepted that the endocannabinoid system (ECS) is a modulator of neuroinflammation associated with neurodegenerative disorders, including Alzheimer's disease (AD). Thus, expression of the cannabinoid receptor 2 (CB2) is induced in plaque-associated microglia and astrocytes in brain tissues from AD patients and in genetic mouse models expressing pathogenic variants of the amyloid precursor protein (APP). However, the exact mechanism of CB2 signaling in this mouse model remains elusive, because the genetic deletion of CB2 and the pharmacological activation of CB2 both reduced neuroinflammation. Here, we demonstrate that CB2 deletion also improved cognitive and learning deficits in APP/PS1*CB2-/- mice. This was accompanied by reduced neuronal loss and decreased plaque levels and coincided with increased expression of Aβ degrading enzymes. Interestingly, plaque-associated microglia in APP/PS1*CB2-/- mice showed a less activated morphology, while plaques were smaller and more condensed than in APP/PS1 mice. Taken together, these results indicate a beneficial effect of CB2-deficiency in APP transgenic mice. CB2 appears to be part of a protective system that may be detrimental when engaged continuously.
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Affiliation(s)
- Anne-Caroline Schmöle
- Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Bonn, Germany
| | - Ramona Lundt
- Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Bonn, Germany
| | - Gregor Toporowski
- Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Bonn, Germany
| | - Jan N Hansen
- Center of Advanced European Studies and Research (Caesar), Max Planck research group "Neuroimmunology", Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Eva Beins
- Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Bonn, Germany
| | - Annett Halle
- Center of Advanced European Studies and Research (Caesar), Max Planck research group "Neuroimmunology", Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Medical Faculty, Bonn, Germany
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63
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Franco-Bocanegra DK, McAuley C, Nicoll JAR, Boche D. Molecular Mechanisms of Microglial Motility: Changes in Ageing and Alzheimer's Disease. Cells 2019; 8:cells8060639. [PMID: 31242692 PMCID: PMC6627151 DOI: 10.3390/cells8060639] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 12/25/2022] Open
Abstract
Microglia are the tissue-resident immune cells of the central nervous system, where they constitute the first line of defense against any pathogens or injury. Microglia are highly motile cells and in order to carry out their function, they constantly undergo changes in their morphology to adapt to their environment. The microglial motility and morphological versatility are the result of a complex molecular machinery, mainly composed of mechanisms of organization of the actin cytoskeleton, coupled with a “sensory” system of membrane receptors that allow the cells to perceive changes in their microenvironment and modulate their responses. Evidence points to microglia as accountable for some of the changes observed in the brain during ageing, and microglia have a role in the development of neurodegenerative diseases, such as Alzheimer’s disease. The present review describes in detail the main mechanisms driving microglial motility in physiological conditions, namely, the cytoskeletal actin dynamics, with emphasis in proteins highly expressed in microglia, and the role of chemotactic membrane proteins, such as the fractalkine and purinergic receptors. The review further delves into the changes occurring to the involved proteins and pathways specifically during ageing and in Alzheimer’s disease, analyzing how these changes might participate in the development of this disease.
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Affiliation(s)
- Diana K Franco-Bocanegra
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - Ciaran McAuley
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
| | - James A R Nicoll
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
- Department of Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK.
| | - Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK.
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64
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Karunakaran I, Alam S, Jayagopi S, Frohberger SJ, Hansen JN, Kuehlwein J, Hölbling BV, Schumak B, Hübner MP, Gräler MH, Halle A, van Echten-Deckert G. Neural sphingosine 1-phosphate accumulation activates microglia and links impaired autophagy and inflammation. Glia 2019; 67:1859-1872. [PMID: 31231866 DOI: 10.1002/glia.23663] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 02/06/2023]
Abstract
Microglia mediated responses to neuronal damage in the form of neuroinflammation is a common thread propagating neuropathology. In this study, we investigated the microglial alterations occurring as a result of sphingosine 1-phosphate (S1P) accumulation in neural cells. We evidenced increased microglial activation in the brains of neural S1P-lyase (SGPL1) ablated mice (SGPL1fl/fl/Nes ) as shown by an activated and deramified morphology and increased activation markers on microglia. In addition, an increase of pro-inflammatory cytokines in sorted and primary cultured microglia generated from SGPL1 deficient mice was noticed. Further, we assessed autophagy, one of the major mechanisms in the brain that keeps inflammation in check. Indeed, microglial inflammation was accompanied by defective microglial autophagy in SGPL1 ablated mice. Rescuing autophagy by treatment with rapamycin was sufficient to decrease interleukin 6 (IL-6) but not tumor necrosis factor (TNF) secretion in cultured microglia. Rapamycin mediated decrease of IL-6 secretion suggests a particular mechanistic target of rapamycin (mTOR)-IL-6 link and appeared to be microglia specific. Using pharmacological inhibitors of the major receptors of S1P expressed in the microglia, we identified S1P receptor 2 (S1PR2) as the mediator of both impaired autophagy and proinflammatory effects. In line with these results, the addition of exogenous S1P to BV2 microglial cells showed similar effects as those observed in the genetic knock out of SGPL1 in the neural cells. In summary, we show a novel role of the S1P-S1PR2 axis in the microglia of mice with neural-targeted SGPL1 ablation and in BV2 microglial cell line exogenously treated with S1P.
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Affiliation(s)
- Indulekha Karunakaran
- LIMES Institute, Membrane Biology & Lipid Biochemistry, University of Bonn, Germany.,Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Shah Alam
- LIMES Institute, Membrane Biology & Lipid Biochemistry, University of Bonn, Germany
| | - Surendar Jayagopi
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Stefan J Frohberger
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Jan N Hansen
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany and Center of Advanced European Studies and Research, Bonn, Germany
| | - Janina Kuehlwein
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Benedikt V Hölbling
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany and Center of Advanced European Studies and Research, Bonn, Germany
| | - Beatrix Schumak
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany
| | - Markus H Gräler
- Department of Anaesthesiology and Intensive Care Medicine, Center for Sepsis Control and Care (CSCC), and the Center for Molecular Biomedicine (CMB), Jena University Hospital, Jena, Germany
| | - Annett Halle
- German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany and Center of Advanced European Studies and Research, Bonn, Germany
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65
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Stephen TL, Cacciottolo M, Balu D, Morgan TE, LaDu MJ, Finch CE, Pike CJ. APOE genotype and sex affect microglial interactions with plaques in Alzheimer's disease mice. Acta Neuropathol Commun 2019; 7:82. [PMID: 31113487 PMCID: PMC6528326 DOI: 10.1186/s40478-019-0729-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/27/2019] [Indexed: 12/15/2022] Open
Abstract
Microglia affect Alzheimer’s disease (AD) pathogenesis in opposing manners, by protecting against amyloid accumulation in early phases of the disease and promoting neuropathology in advanced stages. Recent research has identified specific microglial interactions with amyloid plaques that exert important protective functions including attenuation of early pathology. It is unknown how these protective microglial interactions with plaques are affected by apolipoprotein E (APOE) genotype and sex, two well-established AD risk factors that modulate microglial function. We investigated this question using quantitative confocal microscopy to compare microglial interactions with amyloid plaques in male and female EFAD mice across APOE3 and APOE4 genotypes at 6 months of age. We observed that microglial coverage of plaques is highest in male APOE3 mice with significant reductions in coverage observed with both APOE4 genotype and female sex. Plaque compaction, a beneficial consequence of microglial interactions with plaques, showed a similar pattern in which APOE4 genotype and female sex were associated with significantly lower values. Within the plaque environment, microglial expression of triggering receptor expressed on myeloid cells 2 (TREM2), a known regulator of microglial plaque coverage, was highest in male APOE3 mice and reduced by APOE4 genotype and female sex. These differences in plaque interactions were unrelated to the number of microglial processes in the plaque environment across groups. Interestingly, the pattern of amyloid burden across groups was opposite to that of microglial plaque coverage, with APOE4 genotype and female sex showing the highest amyloid levels. These findings suggest a possible mechanism by which microglia may contribute to the increased AD risk associated with APOE4 genotype and female sex.
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66
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Jin LW, Lucente JD, Nguyen HM, Singh V, Singh L, Chavez M, Bushong T, Wulff H, Maezawa I. Repurposing the KCa3.1 inhibitor senicapoc for Alzheimer's disease. Ann Clin Transl Neurol 2019; 6:723-738. [PMID: 31019997 PMCID: PMC6469250 DOI: 10.1002/acn3.754] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/06/2019] [Accepted: 02/10/2019] [Indexed: 01/01/2023] Open
Abstract
Objective Microglia play a pivotal role in the initiation and progression of Alzheimer's disease (AD). We here tested the therapeutic hypothesis that the Ca2+‐activated potassium channel KCa3.1 constitutes a potential target for treating AD by reducing neuroinflammation. Methods To determine if KCa3.1 is relevant to AD, we tested if treating cultured microglia or hippocampal slices with Aβ oligomer (AβO) activated KCa3.1 in microglia, and if microglial KCa3.1 was upregulated in 5xFAD mice and in human AD brains. The expression/activity of KCa3.1 was examined by qPCR, Western blotting, immunohistochemistry, and whole‐cell patch‐clamp. To investigate the role of KCa3.1 in AD pathology, we resynthesized senicapoc, a clinically tested KCa3.1 blocker, and determined its pharmacokinetic properties and its effect on microglial activation, Aβ deposition and hippocampal long‐term potentiation (hLTP) in 5xFAD mice. Results We found markedly enhanced microglial KCa3.1 expression/activity in brains of both 5xFAD mice and AD patients. In hippocampal slices, microglial KCa3.1 expression/activity was increased by AβO treatment, and its inhibition diminished the proinflammatory and hLTP‐impairing activities of AβO. Senicapoc exhibited excellent brain penetrance and oral availability, and in 5xFAD mice, reduced neuroinflammation, decreased cerebral amyloid load, and enhanced hippocampal neuronal plasticity. Interpretation Our results prompt us to propose repurposing senicapoc for AD clinical trials, as senicapoc has excellent pharmacological properties and was safe and well‐tolerated in a prior phase‐3 clinical trial for sickle cell anemia. Such repurposing has the potential to expedite the urgently needed new drug discovery for AD.
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Affiliation(s)
- Lee-Way Jin
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Jacopo Di Lucente
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Hai M Nguyen
- Department of Pharmacology University of California Davis Davis California
| | - Vikrant Singh
- Department of Pharmacology University of California Davis Davis California
| | - Latika Singh
- Department of Pharmacology University of California Davis Davis California
| | - Monique Chavez
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Trevor Bushong
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
| | - Heike Wulff
- Department of Pharmacology University of California Davis Davis California
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine University of California Davis Medical Center Sacramento California
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67
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Izquierdo P, Attwell D, Madry C. Ion Channels and Receptors as Determinants of Microglial Function. Trends Neurosci 2019; 42:278-292. [PMID: 30678990 DOI: 10.1016/j.tins.2018.12.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/20/2022]
Abstract
Microglia provide immune surveillance of the CNS. They display diverse behaviors, including nondirectional and directed motility of their processes, phagocytosis of targets such as dying neurons or superfluous synapses, and generation of reactive oxygen species (ROS) and cytokines. Many of these functions are mediated by ion channels and cell surface receptors, the expression of which varies with the many morphological and functional states that microglial cells can adopt. Recent progress in understanding microglial function has been facilitated by applying classical cell physiological techniques in situ, such as patch-clamping and live imaging, and cell-specific transcriptomic analyses. Here, we review the contribution of microglial ion channels and receptors to microglial and brain function.
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Affiliation(s)
- Pablo Izquierdo
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower St, London, WC1E 6BT, UK
| | - David Attwell
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower St, London, WC1E 6BT, UK.
| | - Christian Madry
- Institute of Neurophysiology, Charité - Universitätsmedizin, 10117 Berlin, Germany.
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68
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Bassler K, Schulte-Schrepping J, Warnat-Herresthal S, Aschenbrenner AC, Schultze JL. The Myeloid Cell Compartment-Cell by Cell. Annu Rev Immunol 2019; 37:269-293. [PMID: 30649988 DOI: 10.1146/annurev-immunol-042718-041728] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Myeloid cells are a major cellular compartment of the immune system comprising monocytes, dendritic cells, tissue macrophages, and granulocytes. Models of cellular ontogeny, activation, differentiation, and tissue-specific functions of myeloid cells have been revisited during the last years with surprising results; for example, most tissue macrophages are yolk sac derived, monocytes and macrophages follow a multidimensional model of activation, and tissue signals have a significant impact on the functionality of all these cells. While these exciting results have brought these cells back to center stage, their enormous plasticity and heterogeneity, during both homeostasis and disease, are far from understood. At the same time, the ongoing revolution in single-cell genomics, with single-cell RNA sequencing (scRNA-seq) leading the way, promises to change this. Prevailing models of hematopoiesis with distinct intermediates are challenged by scRNA-seq data suggesting more continuous developmental trajectories in the myeloid cell compartment. Cell subset structures previously defined by protein marker expression need to be revised based on unbiased analyses of scRNA-seq data. Particularly in inflammatory conditions, myeloid cells exhibit substantially vaster heterogeneity than previously anticipated, and work performed within large international projects, such as the Human Cell Atlas, has already revealed novel tissue macrophage subsets. Based on these exciting developments, we propose the next steps to a full understanding of the myeloid cell compartment in health and diseases.
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Affiliation(s)
- Kevin Bassler
- Department for Genomics and Immunoregulation, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany; , , , ,
| | - Jonas Schulte-Schrepping
- Department for Genomics and Immunoregulation, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany; , , , ,
| | - Stefanie Warnat-Herresthal
- Department for Genomics and Immunoregulation, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany; , , , ,
| | - Anna C Aschenbrenner
- Department for Genomics and Immunoregulation, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany; , , , , .,Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen 6525, The Netherlands
| | - Joachim L Schultze
- Department for Genomics and Immunoregulation, Life and Medical Sciences (LIMES) Institute, University of Bonn, 53115 Bonn, Germany; , , , , .,PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases and the University of Bonn, 53115 Bonn, Germany
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69
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Takatori S, Wang W, Iguchi A, Tomita T. Genetic Risk Factors for Alzheimer Disease: Emerging Roles of Microglia in Disease Pathomechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1118:83-116. [PMID: 30747419 DOI: 10.1007/978-3-030-05542-4_5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The accumulation of aggregated amyloid β (Aβ) peptides in the brain is deeply involved in Alzheimer disease (AD) pathogenesis. Mutations in APP and presenilins play major roles in Aβ pathology in rare autosomal-dominant forms of AD, whereas pathomechanisms of sporadic AD, accounting for the majority of cases, remain unknown. In this chapter, we review current knowledge on genetic risk factors of AD, clarified by recent advances in genome analysis technology. Interestingly, TREM2 and many genes associated with disease risk are predominantly expressed in microglia, suggesting that these risk factors are involved in pathogenicity through common mechanisms involving microglia. Therefore, we focus on factors closely associated with microglia and discuss their possible roles in pathomechanisms of AD. Furthermore, we review current views on the pathological roles of microglia and emphasize the importance of microglial changes in response to Aβ deposition and mechanisms underlying the phenotypic changes. Importantly, functional outcomes of microglial activation can be both protective and deleterious to neurons. We further describe the involvement of microglia in tau pathology and the activation of other glial cells. Through these topics, we shed light on microglia as a promising target for drug development for AD and other neurological disorders.
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Affiliation(s)
- Sho Takatori
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Wenbo Wang
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Akihiro Iguchi
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
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70
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Chen C, Liang Z, Zhou B, Li X, Lui C, Ip NY, Qu JY. In Vivo Near-Infrared Two-Photon Imaging of Amyloid Plaques in Deep Brain of Alzheimer's Disease Mouse Model. ACS Chem Neurosci 2018; 9:3128-3136. [PMID: 30067906 DOI: 10.1021/acschemneuro.8b00306] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Abnormal deposition of brain amyloid is a major hallmark of Alzheimer's disease (AD). The toxic extracellular amyloid plaques originating from the aberrant aggregation of beta-amyloid (Aβ) protein are considered to be the major cause of clinical deficits such as memory loss and cognitive impairment. Two-photon excited fluorescence (TPEF) microscopy provides high spatial resolution, minimal invasiveness, and long-term monitoring capability. TPEF imaging of amyloid plaques in AD transgenic mice models has greatly facilitated studies of the AD pathological mechanism. However, the imaging of deep cortical layers is still hampered by the conventional amyloid probes with short excitation/emission wavelength. In this work, we report that a near-infrared (NIR) probe, named CRANAD-3, is far superior for deep in vivo TPEF imaging of brain amyloid in comparison with the commonly used short-wavelength probe. Our findings show that the major interference for TPEF signal of the NIR probe is from the autofluorescence of lipofuscin, the "aging-pigment" in the brain. To eliminate the interference, we characterized the lipofuscin fluorescence in the aged brains of AD mice and found that it has unique broad emission and short lifetime. The lipofuscin signal can be clearly separated from the fluorescence of CRANAD-3 and fluorescent protein via a ratio-based unmixing method. Our results demonstrate the great advantages of NIR probes for in vivo deep-tissue imaging of amyloid plaques in AD.
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Affiliation(s)
- Congping Chen
- Biophotonics Research Laboratory, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Zhuoyi Liang
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Biao Zhou
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Xuesong Li
- Biophotonics Research Laboratory, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Caleb Lui
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Nancy Y. Ip
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
| | - Jianan Y. Qu
- Biophotonics Research Laboratory, Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P. R. China
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Ugolini F, Lana D, Nardiello P, Nosi D, Pantano D, Casamenti F, Giovannini MG. Different Patterns of Neurodegeneration and Glia Activation in CA1 and CA3 Hippocampal Regions of TgCRND8 Mice. Front Aging Neurosci 2018; 10:372. [PMID: 30483118 PMCID: PMC6243135 DOI: 10.3389/fnagi.2018.00372] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/26/2018] [Indexed: 01/24/2023] Open
Abstract
We investigated the different patterns of neurodegeneration and glia activation in CA1 and CA3 hippocampal areas of TgCRND8 mice. The main feature of this transgenic model is the rapid development of the amyloid pathology, which starts already at 3 months of age. We performed immunohistochemical analyses to compare the different sensibility of the two hippocampal regions to neurodegeneration. We performed qualitative and quantitative evaluations by fluorescence immunohistochemistry with double or triple staining, followed by confocal microscopy and digital image analysis in stratum pyramidale (SP) and stratum radiatum (SR) of CA1 and CA3, separately. We evaluated time-dependent Aβ plaques deposition, expression of inflammatory markers, as well as quantitative and morphological alterations of neurons and glia in transgenic mice at 3 (Tg 3M) and 6 (Tg 6M) months of age, compared to WT mice. In CA1 SR of Tg 6M mice, we found significantly more Medium and Large plaques than in CA3. The pattern of neurodegeneration and astrocytes activation was different in the two areas, indicating higher sensitivity of CA1. In the CA1 SP of Tg 6M mice, we found signs of reactive astrogliosis, such as increase of astrocytes density in SP, increase of GFAP expression in SR, and elongation of astrocytes branches. We found also common patterns of glia activation and neurodegenerative processes in CA1 and CA3 of Tg 6M mice: significant increase of total and reactive microglia density in SP and SR, increased expression of TNFα, of iNOS, and IL1β in astrocytes and increased density of neurons-astrocytes-microglia triads. In CA1 SP, we found decrease of volume and number of pyramidal neurons, paralleled by increase of apoptosis, and, consequently, shrinkage of CA1 SP. These data demonstrate that in TgCRND8 mice, the responses of neurons and glia to neurodegenerative patterns induced by Aβ plaques deposition is not uniform in the two hippocampal areas, and in CA1 pyramidal neurons, the higher sensitivity may be related to the different plaque distribution in this area. All these modifications may be at the basis of memory loss, the peculiar symptom of AD, which was demonstrated in this transgenic mouse model of Aβ deposition, even at early stages.
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Affiliation(s)
- Filippo Ugolini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Pamela Nardiello
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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Han J, Zhu K, Zhang X, Harris RA. Enforced microglial depletion and repopulation as a promising strategy for the treatment of neurological disorders. Glia 2018; 67:217-231. [PMID: 30378163 PMCID: PMC6635749 DOI: 10.1002/glia.23529] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/17/2018] [Accepted: 08/22/2018] [Indexed: 01/18/2023]
Abstract
Microglia are prominent immune cells in the central nervous system (CNS) and are critical players in both neurological development and homeostasis, and in neurological diseases when dysfunctional. Our previous understanding of the phenotypes and functions of microglia has been greatly extended by a dearth of recent investigations. Distinct genetically defined subsets of microglia are now recognized to perform their own independent functions in specific conditions. The molecular profiling of single microglial cells indicates extensively heterogeneous reactions in different neurological disorders, resulting in multiple potentials for crosstalk with other kinds of CNS cells such as astrocytes and neurons. In settings of neurological diseases it could thus be prudent to establish effective cell‐based therapies by targeting entire microglial networks. Notably, activated microglial depletion through genetic targeting or pharmacological therapies within a suitable time window can stimulate replenishment of the CNS niche with new microglia. Additionally, enforced repopulation through provision of replacement cells also represents a potential means of exchanging dysfunctional with functional microglia. In each setting the newly repopulated microglia might have the potential to resolve ongoing neuroinflammation. In this review, we aim to summarize the most recent knowledge of microglia and to highlight microglial depletion and subsequent repopulation as a promising cell replacement therapy. Although glial cell replacement therapy is still in its infancy and future translational studies are still required, the approach is scientifically sound and provides new optimism for managing the neurotoxicity and neuroinflammation induced by activated microglia.
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Affiliation(s)
- Jinming Han
- Applied Immunology and Immunotherapy, Department of Clinical NeuroscienceKarolinska Institutet, Center for Molecular Medicine, Karolinska University Hospital at SolnaStockholmSweden
| | - Keying Zhu
- Applied Immunology and Immunotherapy, Department of Clinical NeuroscienceKarolinska Institutet, Center for Molecular Medicine, Karolinska University Hospital at SolnaStockholmSweden
| | - Xing‐Mei Zhang
- Applied Immunology and Immunotherapy, Department of Clinical NeuroscienceKarolinska Institutet, Center for Molecular Medicine, Karolinska University Hospital at SolnaStockholmSweden
| | - Robert A. Harris
- Applied Immunology and Immunotherapy, Department of Clinical NeuroscienceKarolinska Institutet, Center for Molecular Medicine, Karolinska University Hospital at SolnaStockholmSweden
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73
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Shen Z, Bao X, Wang R. Clinical PET Imaging of Microglial Activation: Implications for Microglial Therapeutics in Alzheimer's Disease. Front Aging Neurosci 2018; 10:314. [PMID: 30349474 PMCID: PMC6186779 DOI: 10.3389/fnagi.2018.00314] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
In addition to extracellular β-amyloid plaques and intracellular neurofibrillary tangles, neuroinflammation has been identified as a key pathological characteristic of Alzheimer's disease (AD). Once activated, neuroinflammatory cells called microglia acquire different activation phenotypes. At the early stage of AD, activated microglia are mainly dominated by the neuroprotective and anti-inflammatory M2 phenotype. Conversely, in the later stage of AD, the excessive activation of microglia is considered detrimental and pro-inflammatory, turning into the M1 phenotype. Therapeutic strategies targeting the modulation of microglia may regulate their specific phenotype. Fortunately, with the rapid development of in vivo imaging methodologies, visualization of microglial activation has been well-explored. In this review, we summarize the critical role of activated microglia during the pathogenesis of AD and current studies concerning imaging of microglial activation in AD patients. We explore the possibilities for identifying activated microglial phenotypes with imaging techniques and highlight promising therapies that regulate the microglial phenotype in AD mice.
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Affiliation(s)
- Zhiwei Shen
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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Thei L, Imm J, Kaisis E, Dallas ML, Kerrigan TL. Microglia in Alzheimer's Disease: A Role for Ion Channels. Front Neurosci 2018; 12:676. [PMID: 30323735 PMCID: PMC6172337 DOI: 10.3389/fnins.2018.00676] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/07/2018] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease is the most common form of dementia, it is estimated to affect over 40 million people worldwide. Classically, the disease has been characterized by the neuropathological hallmarks of aggregated extracellular amyloid-β and intracellular paired helical filaments of hyperphosphorylated tau. A wealth of evidence indicates a pivotal role for the innate immune system, such as microglia, and inflammation in the pathology of Alzheimer's disease. The over production and aggregation of Alzheimer's associated proteins results in chronic inflammation and disrupts microglial clearance of these depositions. Despite being non-excitable, microglia express a diverse array of ion channels which shape their physiological functions. In support of this, there is a growing body of evidence pointing to the involvement of microglial ion channels contributing to neurodegenerative diseases such as Alzheimer's disease. In this review, we discuss the evidence for an array of microglia ion channels and their importance in modulating microglial homeostasis and how this process could be disrupted in Alzheimer's disease. One promising avenue for assessing the role that microglia play in the initiation and progression of Alzheimer's disease is through using induced pluripotent stem cell derived microglia. Here, we examine what is already understood in terms of the molecular underpinnings of inflammation in Alzheimer's disease, and the utility that inducible pluripotent stem cell derived microglia may have to advance this knowledge. We outline the variability that occurs between the use of animal and human models with regards to the importance of microglial ion channels in generating a relevant functional model of brain inflammation. Overcoming these hurdles will be pivotal in order to develop new drug targets and progress our understanding of the pathological mechanisms involved in Alzheimer's disease.
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Affiliation(s)
- Laura Thei
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Jennifer Imm
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
| | - Eleni Kaisis
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Mark L Dallas
- Reading School of Pharmacy, University of Reading, Reading, United Kingdom
| | - Talitha L Kerrigan
- University of Exeter Medical School, University of Exeter, Exeter, United Kingdom
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