101
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Schlepckow K, Kleinberger G, Fukumori A, Feederle R, Lichtenthaler SF, Steiner H, Haass C. An Alzheimer-associated TREM2 variant occurs at the ADAM cleavage site and affects shedding and phagocytic function. EMBO Mol Med 2018; 9:1356-1365. [PMID: 28855300 PMCID: PMC5623859 DOI: 10.15252/emmm.201707672] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequence variations occurring in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) support an essential function of microglia and innate immunity in the pathogenesis of Alzheimer's disease (AD) and other neurodegenerative disorders. TREM2 matures within the secretory pathway, and its ectodomain is shed on the plasma membrane. Missense mutations in the immunoglobulin (Ig)‐like domain such as p.T66M and p.Y38C retain TREM2 within the endoplasmic reticulum and reduce shedding as well as TREM2‐dependent phagocytosis. Using mass spectrometry, we have now determined the cleavage site of TREM2. TREM2 is shed by proteases of the ADAM (a disintegrin and metalloproteinase domain containing protein) family C‐terminal to histidine 157, a position where an AD‐associated coding variant has been discovered (p.H157Y) in the Han Chinese population. Opposite to the characterized mutations within the Ig‐like domain, such as p.T66M and p.Y38C, the p.H157Y variant within the stalk region leads to enhanced shedding of TREM2. Elevated ectodomain shedding reduces cell surface full‐length TREM2 and lowers TREM2‐dependent phagocytosis. Therefore, two seemingly opposite cellular effects of TREM2 variants, namely reduced versus enhanced shedding, result in similar phenotypic outcomes by reducing cell surface TREM2.
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Affiliation(s)
- Kai Schlepckow
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gernot Kleinberger
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Akio Fukumori
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Regina Feederle
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Helmholtz Center Munich, German Research Center for Environmental Health, Institute for Diabetes and Obesity, Core Facility Monoclonal Antibody Development, Neuherberg, Germany
| | - Stefan F Lichtenthaler
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Neuroproteomics, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.,Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Harald Steiner
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
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102
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Filipello F, Morini R, Corradini I, Zerbi V, Canzi A, Michalski B, Erreni M, Markicevic M, Starvaggi-Cucuzza C, Otero K, Piccio L, Cignarella F, Perrucci F, Tamborini M, Genua M, Rajendran L, Menna E, Vetrano S, Fahnestock M, Paolicelli RC, Matteoli M. The Microglial Innate Immune Receptor TREM2 Is Required for Synapse Elimination and Normal Brain Connectivity. Immunity 2018; 48:979-991.e8. [PMID: 29752066 DOI: 10.1016/j.immuni.2018.04.016] [Citation(s) in RCA: 375] [Impact Index Per Article: 62.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 01/19/2018] [Accepted: 04/13/2018] [Indexed: 02/07/2023]
Abstract
The triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial innate immune receptor associated with a lethal form of early, progressive dementia, Nasu-Hakola disease, and with an increased risk of Alzheimer's disease. Microglial defects in phagocytosis of toxic aggregates or apoptotic membranes were proposed to be at the origin of the pathological processes in the presence of Trem2 inactivating mutations. Here, we show that TREM2 is essential for microglia-mediated synaptic refinement during the early stages of brain development. The absence of Trem2 resulted in impaired synapse elimination, accompanied by enhanced excitatory neurotransmission and reduced long-range functional connectivity. Trem2-/- mice displayed repetitive behavior and altered sociability. TREM2 protein levels were also negatively correlated with the severity of symptoms in humans affected by autism. These data unveil the role of TREM2 in neuronal circuit sculpting and provide the evidence for the receptor's involvement in neurodevelopmental diseases.
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Affiliation(s)
- Fabia Filipello
- Humanitas University, Department of Biomedical Sciences, Via Rita Levi Montalcini, 20090 Pieve Emanuele - Milan, Italy
| | - Raffaella Morini
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Irene Corradini
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy; IN-CNR, 20129 Milano, Italy
| | - Valerio Zerbi
- Neural Control of Movement Lab, HEST, ETH Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Alice Canzi
- Humanitas University, Department of Biomedical Sciences, Via Rita Levi Montalcini, 20090 Pieve Emanuele - Milan, Italy
| | - Bernadeta Michalski
- Department of Psychiatry & Behavioural Neurosciences, HSC-4N80, McMaster University, Hamilton, ON, Canada
| | - Marco Erreni
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Marija Markicevic
- Neural Control of Movement Lab, HEST, ETH Zürich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Chiara Starvaggi-Cucuzza
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Karel Otero
- Department of Neuroimmunology, Acute Neurology and Pain, Biogen Inc., 115 Broadway, Cambridge, MA, USA
| | - Laura Piccio
- Department of Neurology, Washington University, St. Louis, MO, USA
| | | | - Fabio Perrucci
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Matteo Tamborini
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Marco Genua
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, IREM, University of Zurich, Schlieren, Switzerland
| | - Elisabetta Menna
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy; IN-CNR, 20129 Milano, Italy
| | - Stefania Vetrano
- Humanitas University, Department of Biomedical Sciences, Via Rita Levi Montalcini, 20090 Pieve Emanuele - Milan, Italy
| | - Margaret Fahnestock
- Department of Psychiatry & Behavioural Neurosciences, HSC-4N80, McMaster University, Hamilton, ON, Canada
| | - Rosa Chiara Paolicelli
- Systems and Cell Biology of Neurodegeneration, IREM, University of Zurich, Schlieren, Switzerland
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Via Manzoni 56, 20089 Rozzano - Milan, Italy; IN-CNR, 20129 Milano, Italy.
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103
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Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating, uniformly lethal degenerative disorder of motor neurons that overlaps clinically with frontotemporal dementia (FTD). Investigations of the 10% of ALS cases that are transmitted as dominant traits have revealed numerous gene mutations and variants that either cause these disorders or influence their clinical phenotype. The evolving understanding of the genetic architecture of ALS has illuminated broad themes in the molecular pathophysiology of both familial and sporadic ALS and FTD. These central themes encompass disturbances of protein homeostasis, alterations in the biology of RNA binding proteins, and defects in cytoskeletal dynamics, as well as numerous downstream pathophysiological events. Together, these findings from ALS genetics provide new insight into therapies that target genetically distinct subsets of ALS and FTD.
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Affiliation(s)
- Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Robert H Brown
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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104
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Zhang Y, Feng S, Nie K, Li Y, Gao Y, Gan R, Wang L, Li B, Sun X, Wang L, Zhang Y. TREM2 modulates microglia phenotypes in the neuroinflammation of Parkinson's disease. Biochem Biophys Res Commun 2018; 499:797-802. [PMID: 29621548 DOI: 10.1016/j.bbrc.2018.03.226] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 03/31/2018] [Indexed: 11/19/2022]
Abstract
Neuroinflammation and overactivated microglia underlies the pathogenesis of Parkinson's disease (PD). Furthermore, microglia could polarize into classic inflammatory M1 and immunosuppressive M2 phenotype. Thus, inhibiting the overactivated inflammatory M1 microglia by promoting the transformation of microglia to the protective M2 phenotype provides potential therapy for PD, but the mechanism that modulates microglia polarization remains unknown. Triggering receptor expressed on myeloid cells-2 (TREM2) is a recently identified immune receptor expressed by the microglia in the brain. Emerging evidence indicates that TREM2 enhances the phagocytosis function of microglia and suppress inflammation. Based on these evidence, we hypothesized that TREM2 might play a protective role through regulating microglia polarization. Here, we employ a lentiviral strategy to overexpress or suppress TREM2 on microglia and found that TREM2 was essential for M2 microglia polarization. Knockdown of TREM2 in BV2 microglia inhibited M2 polarization and lead to exaggeration of M1 microglial inflammatory responses, whereas overexpression of TREM2 promoted M2 polarization and alleviated microglial inflammation. We also observed that the TREM2 level was higher in the midbrain of PD mice, which was accompanied by an elevated level of Arginase-1 and increased proinflammatory cytokines, suggesting that TREM2 is an important factor in switching the microglia phenotypes. Taken together, these findings indicate that TREM2 plays a crucial role in altering the proinflammatory M1 microglia to M2 phenotype and has beneficial effects in the immune pathogenesis of PD.
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Affiliation(s)
- Youwen Zhang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; Department of Neurology, The People's Hospital of Gaozhou, Guangdong, China
| | - Shujun Feng
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Kun Nie
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yan Li
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yuyuan Gao
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Rong Gan
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Limin Wang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Bing Li
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Xuegang Sun
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Lijuan Wang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Yuhu Zhang
- Department of Neurology, Guangdong Neuroscience Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
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105
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Peplonska B, Berdynski M, Mandecka M, Barczak A, Kuzma-Kozakiewicz M, Barcikowska M, Zekanowski C. TREM2 variants in neurodegenerative disorders in the Polish population. Homozygosity and compound heterozygosity in FTD patients. Amyotroph Lateral Scler Frontotemporal Degener 2018; 19:407-412. [PMID: 29557178 DOI: 10.1080/21678421.2018.1451894] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Activation of the TREM2 receptor on microglia stimulates phagocytosis and decreases the microglial proinflammatory response. Mutations in exon 2 of the TREM2 gene have been reported to be associated with various neurodegenerative diseases characterized by chronic inflammation. The aim of our study was to evaluate exon 2 of TREM2 gene variants as a putative genetic risk factor for Alzheimer's disease (AD), frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS) in the Polish population. The results were interpreted using previously published data, especially highlighting differences in the prevalence of the variants among Caucasian subpopulations across different geographic regions. The DNA sequence of exon 2 of TREM2 was analyzed in 811 subjects (274 AD, 135 FTD, 194 ALS patients, and 208 neurologically healthy controls). Nine heterozygous variants were detected, including two novel ones: p.G29 = and c.41-2_3insA, found respectively in a control and an ALS patient. Additionally, we identified one homozygous and two compound heterozygous FTD patients. We confirm previous data that homozygous and compound heterozygous TREM2 mutations can be causative for FTD.
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Affiliation(s)
- Beata Peplonska
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
| | - Mariusz Berdynski
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
| | - Monika Mandecka
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
| | - Anna Barczak
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
| | - Magdalena Kuzma-Kozakiewicz
- b Department of Neurology , and.,c Neurodegenerative Diseases Research Group Medical University of Warsaw , Warsaw , Poland
| | - Maria Barcikowska
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
| | - Cezary Zekanowski
- a Department of Neurodegenerative Disorders , Mossakowski Medical Research Centre Polish Academy of Sciences , Warsaw , Poland
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106
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Abstract
Biomarkers of Huntington’s disease (HD) in cerebrospinal fluid (CSF) could be of value in elucidating the biology of this genetic neurodegenerative disease, as well as in the development of novel therapeutics. Deranged synaptic and immune function have been reported in HD, and concentrations of the synaptic protein neurogranin and the microglial protein TREM2 are increased in other neurodegenerative diseases. We therefore used ELISAs to quantify neurogranin and TREM2 in CSF samples from HD mutation carriers and controls. CSF neurogranin concentration was not significantly altered in HD compared to controls, nor was it significantly associated with disease burden score, total functional capacity or motor score. An apparent increase in CSF TREM2 in manifest HD was determined to be due to increasing TREM2 with age. After age adjustment, there was no significant alteration of TREM2 in either HD group, nor any association with motor, functional or cognitive score, or brain volume quantified by MRI. Both analyses were well-powered, and sample size calculations indicated that several thousand samples per group would be needed to prove that disease-associated alterations do in fact exist. We conclude that neither neurogranin nor TREM2 is a useful biofluid biomarker for disease processes in Huntington’s disease.
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107
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Chen H, Kankel MW, Su SC, Han SWS, Ofengeim D. Exploring the genetics and non-cell autonomous mechanisms underlying ALS/FTLD. Cell Death Differ 2018; 25:648-662. [PMID: 29459769 DOI: 10.1038/s41418-018-0060-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, was first described in 1874, a flurry of genetic discoveries in the last 10 years has markedly increased our understanding of this disease. These findings have not only enhanced our knowledge of mechanisms leading to ALS, but also have revealed that ALS shares many genetic causes with another neurodegenerative disease, frontotemporal lobar dementia (FTLD). In this review, we survey how recent genetic studies have bridged our mechanistic understanding of these two related diseases and how the genetics behind ALS and FTLD point to complex disorders, implicating non-neuronal cell types in disease pathophysiology. The involvement of non-neuronal cell types is consistent with a non-cell autonomous component in these diseases. This is further supported by studies that identified a critical role of immune-associated genes within ALS/FTLD and other neurodegenerative disorders. The molecular functions of these genes support an emerging concept that various non-autonomous functions are involved in neurodegeneration. Further insights into such a mechanism(s) will ultimately lead to a better understanding of potential routes of therapeutic intervention. Facts ALS and FTLD are severe neurodegenerative disorders on the same disease spectrum. Multiple cellular processes including dysregulation of RNA homeostasis, imbalance of proteostasis, contribute to ALS/FTLD pathogenesis. Aberrant function in non-neuronal cell types, including microglia, contributes to ALS/FTLD. Strong neuroimmune and neuroinflammatory components are associated with ALS/FTLD patients. Open Questions Why can patients with similar mutations have different disease manifestations, i.e., why do C9ORF72 mutations lead to motor neuron loss in some patients while others exhibit loss of neurons in the frontotemporal lobe? Do ALS causal mutations result in microglial dysfunction and contribute to ALS/FTLD pathology? How do microglia normally act to mitigate neurodegeneration in ALS/FTLD? To what extent do cellular signaling pathways mediate non-cell autonomous communications between distinct central nervous system (CNS) cell types during disease? Is it possible to therapeutically target specific cell types in the CNS?
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Affiliation(s)
- Hongbo Chen
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
| | - Mark W Kankel
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Susan C Su
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Steve W S Han
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA.,Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,GSK, Upper Providence, PA, 19426, USA
| | - Dimitry Ofengeim
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA. .,Sanofi Neuroscience, Framingham, MA, USA.
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108
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Novel targets in Alzheimer's disease: A special focus on microglia. Pharmacol Res 2018; 130:402-413. [PMID: 29391235 DOI: 10.1016/j.phrs.2018.01.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/12/2018] [Accepted: 01/26/2018] [Indexed: 02/07/2023]
Abstract
Several years after the intriguing novelty in the β-amyloid (Aβ) cascade hypothesis, where the Aβ oligomers emerged as the most detrimental species in the neuropathogenic process of Alzheimer's disease (AD) in place of fibrillar plaques, more recently innate immune system have come on stage as the other prominent factor. Neuroinflammation apparently contributes to AD eziopathogenesis, in large part through overactivation of microglia cells. Genetic and experimental studies strongly support the contribution of the immune system to increasing the risk of AD and participating in its progression. Besides the central immune response mediated by resident microglial cells, peripheral immune challenges may have profound negative effects on brain physiology as well, such as those originating from the gut microbiota. Despite the initial immune response to defend the organism, perpetuation seemingly turns into a chronic detrimental phenomenon that contributes to neuronal dysfunction and exacerbation of the disease. Several new immune-druggable targets are now under investigation, but much still remains to be defined about their precise role and whether and how their physiological activity changes in the injurious context of AD. From a therapeutic perspective, we can undoubtedly consider that AD is no longer solely an Aβ pathology, but rather a multifaceted disorder calling for multi-target therapies. New therapies fighting AD must still counteract Aβ but must also restore appropriate immune defences by tempering maladaptive factors and enabling beneficial responses.
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109
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Mecca C, Giambanco I, Donato R, Arcuri C. Microglia and Aging: The Role of the TREM2-DAP12 and CX3CL1-CX3CR1 Axes. Int J Mol Sci 2018; 19:E318. [PMID: 29361745 PMCID: PMC5796261 DOI: 10.3390/ijms19010318] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 12/21/2022] Open
Abstract
Depending on the species, microglial cells represent 5-20% of glial cells in the adult brain. As the innate immune effector of the brain, microglia are involved in several functions: regulation of inflammation, synaptic connectivity, programmed cell death, wiring and circuitry formation, phagocytosis of cell debris, and synaptic pruning and sculpting of postnatal neural circuits. Moreover, microglia contribute to some neurodevelopmental disorders such as Nasu-Hakola disease (NHD), and to aged-associated neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and others. There is evidence that human and rodent microglia may become senescent. This event determines alterations in the microglia activation status, associated with a chronic inflammation phenotype and with the loss of neuroprotective functions that lead to a greater susceptibility to the neurodegenerative diseases of aging. In the central nervous system (CNS), Triggering Receptor Expressed on Myeloid Cells 2-DNAX activation protein 12 (TREM2-DAP12) is a signaling complex expressed exclusively in microglia. As a microglial surface receptor, TREM2 interacts with DAP12 to initiate signal transduction pathways that promote microglial cell activation, phagocytosis, and microglial cell survival. Defective TREM2-DAP12 functions play a central role in the pathogenesis of several diseases. The CX3CL1 (fractalkine)-CX3CR1 signaling represents the most important communication channel between neurons and microglia. The expression of CX3CL1 in neurons and of its receptor CX3CR1 in microglia determines a specific interaction, playing fundamental roles in the regulation of the maturation and function of these cells. Here, we review the role of the TREM2-DAP12 and CX3CL1-CX3CR1 axes in aged microglia and the involvement of these pathways in physiological CNS aging and in age-associated neurodegenerative diseases.
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Affiliation(s)
- Carmen Mecca
- Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy.
| | - Ileana Giambanco
- Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy.
| | - Rosario Donato
- Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy.
- Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy.
| | - Cataldo Arcuri
- Department of Experimental Medicine, Perugia Medical School, University of Perugia, Piazza Lucio Severi 1, 06132 Perugia, Italy.
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110
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Lim SM, Kim YE, Choi WJ, Oh KW, Noh MY, Kwon MS, Nahm M, Kim N, Ki CS, Kim SH. CLEC4C p.K210del variant causes impaired cell surface transport in plasmacytoid dendritic cells of amyotrophic lateral sclerosis. Oncotarget 2018; 7:24942-9. [PMID: 26943047 PMCID: PMC5041881 DOI: 10.18632/oncotarget.7886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 01/29/2016] [Indexed: 01/06/2023] Open
Abstract
The type II C-type lectin CLEC4C is a transmembrane protein selectively expressed on plasmacytoid dendritic cells (PDCs). Although its mechanism of action remains unclear, triggering of the extracellular C-terminal C-type carbohydrate recognition region of CLEC4C regulates the secretion of proinflammatory cytokines and type I IFNs in PDCs. Applying whole-exome sequencing in a patient with juvenile amyotrophic lateral sclerosis (ALS) and both healthy parents, we identified a de novo CLEC4C variant (c.629_631delAGA; p.Lys210del). In this study, we report that the deletion of a lysine residue at the extracellular region of CLEC4C yields a C-terminal dilysine motif that results in endoplasmic reticulum (ER) retention of the protein in transfected HeLa and Jurkat T lymphoma cell models. As a consequence, a decrease in the surface expression of CLEC4C and the ER localization of the mutant construct were observed. Furthermore, depletion of the cell surface CLEC4C level was also observed in the patient PDCs, further suggesting that the variant p.Lys210del CLEC4C may contribute to juvenile ALS susceptibility.
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Affiliation(s)
- Su Min Lim
- Department of Translational Medicine, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea.,Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
| | | | - Won Jun Choi
- Department of Neurology, Sheikh Khalifa Specialty Hospital, Ras Al Khaimah, United Arab Emirates
| | - Ki-Wook Oh
- Department of Neurology, College of Medicine, Hanyang University, Seoul, Republic of Korea.,Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
| | - Min-Young Noh
- Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
| | - Min-Soo Kwon
- Department of Pharmacology, School of Medicine, CHA University, CHA Bio Complex, Seongnam, Republic of Korea
| | - Minyeop Nahm
- Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
| | - Namshin Kim
- Epigenomics Research Center Genome Institute, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Chang-Seok Ki
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Seung Hyun Kim
- Department of Translational Medicine, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, Republic of Korea.,Department of Neurology, College of Medicine, Hanyang University, Seoul, Republic of Korea.,Cell Therapy Center, Hanyang University Hospital, Seoul, Republic of Korea
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111
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Abstract
Essential tremor (ET) is one of the most common neurologic disorders, and genetic factors are thought to contribute significantly to disease etiology. There has been a relative lack of progress in understanding the genetic etiology of ET. This could reflect a number of factors, including the presence of substantial phenotypic and genotypic heterogeneity. Thus, a meticulous approach to phenotyping is important for genetic research. A lack of standardized phenotyping across studies and patient centers likely has contributed to the relative lack of success of genomewide association studies in ET. To dissect the genetic architecture of ET, whole-genome sequencing will likely be of value. This will allow specific hypotheses about the mode of inheritance and genetic architecture to be tested. A number of approaches still remain unexplored in ET genetics, including the contribution of copy number variants, uncommon moderate-effect alleles, rare variant large-effect alleles (including Mendelian and complex/polygenic modes of inheritance), de novo and gonadal mosaicism, epigenetic changes, and noncoding variation.
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Affiliation(s)
- Lorraine N Clark
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, United States
| | - Elan D Louis
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York; and Departments of Neurology and of Chronic Disease Epidemiology and Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, New Haven, CT, United States.
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112
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Del-Aguila JL, Fernández MV, Schindler S, Ibanez L, Deming Y, Ma S, Saef B, Black K, Budde J, Norton J, Chasse R, Harari O, Goate A, Xiong C, Morris JC, Cruchaga C. Assessment of the Genetic Architecture of Alzheimer's Disease Risk in Rate of Memory Decline. J Alzheimers Dis 2018; 62:745-756. [PMID: 29480181 PMCID: PMC5989565 DOI: 10.3233/jad-170834] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Many genetic studies for Alzheimer's disease (AD) have been focused on the identification of common genetic variants associated with AD risk and not on other aspects of the disease, such as age at onset or rate of dementia progression. There are multiple approaches to untangling the genetic architecture of these phenotypes. We hypothesized that the genetic architecture of rate of progression is different than the risk for developing AD dementia. To test this hypothesis, we used longitudinal clinical data from ADNI and the Knight-ADRC at Washington University, and we calculated PRS (polygenic risk score) based on the IGAP study to compare the genetic architecture of AD risk and dementia progression. Dementia progression was measured by the change of Clinical Dementia Rating Sum of Boxes (CDR)-SB per year. Out of the 21 loci for AD risk, no association with the rate of dementia progression was found. The PRS rate was significantly associated with the rate of dementia progression (β= 0.146, p = 0.03). In the case of rare variants, TREM2 (β= 0.309, p = 0.02) was also associated with the rate of dementia progression. TREM2 variant carriers showed a 23% faster rate of dementia compared with non-variant carriers. In conclusion, our results indicate that the recently identified common and rare variants for AD susceptibility have a limited impact on the rate of dementia progression in AD patients.
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Affiliation(s)
- Jorge L Del-Aguila
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Maria Victoria Fernández
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Suzanne Schindler
- Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Laura Ibanez
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Yuetiva Deming
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Shengmei Ma
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Ben Saef
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Kathleen Black
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - John Budde
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Joanne Norton
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Rachel Chasse
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Oscar Harari
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Alison Goate
- Mount Sinai School of Medicine, New York, NY, USA
| | - Chengjie Xiong
- Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
| | - John C Morris
- Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Carlos Cruchaga
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
- Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
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113
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Suárez-Calvet M, Araque Caballero MÁ, Kleinberger G, Bateman RJ, Fagan AM, Morris JC, Levin J, Danek A, Ewers M, Haass C. Early changes in CSF sTREM2 in dominantly inherited Alzheimer's disease occur after amyloid deposition and neuronal injury. Sci Transl Med 2017; 8:369ra178. [PMID: 27974666 DOI: 10.1126/scitranslmed.aag1767] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 11/23/2016] [Indexed: 12/30/2022]
Abstract
Emerging evidence supports a role for innate immunity and microglia in Alzheimer's disease (AD) pathophysiology. However, no marker related to microglia has been included in the temporal evolution models of AD. TREM2 is a transmembrane protein involved in innate immunity and is selectively expressed by microglia and genetically linked to AD and other neurodegenerative disorders. Its ectodomain is released by proteolysis as a soluble variant (sTREM2) and can be detected in the cerebrospinal fluid (CSF). In patients with autosomal dominant AD, we tested how many years before the expected symptom onset did CSF sTREM2 increase in mutation carriers (MCs) compared to noncarriers (NCs). We also determined the temporal sequence of changes in CSF sTREM2 and markers for amyloid deposition and neurodegeneration as well as cognitive performance. We included 218 participants consisting of 127 MC and 91 NC siblings from the Dominantly Inherited Alzheimer Network. We observed that CSF sTREM2 increased in MCs compared to NCs 5 years before the expected symptom onset and this difference remained significant until 5 years after the expected symptom onset. Changes in CSF sTREM2 occurred after alterations were observed in markers for brain amyloidosis and neuronal injury. We propose that microglial activation occurs several years before the expected symptom onset, but after amyloidosis and neuronal injury have already occurred.
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Affiliation(s)
- Marc Suárez-Calvet
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Biomedical Center, Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Miguel Ángel Araque Caballero
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gernot Kleinberger
- Biomedical Center, Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Randall J Bateman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Knight Alzheimer's Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110, USA.,Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Anne M Fagan
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Knight Alzheimer's Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110, USA.,Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - John C Morris
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA.,Knight Alzheimer's Disease Research Center, Washington University in St. Louis, St. Louis, MO 63110, USA.,Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Johannes Levin
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Adrian Danek
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Department of Neurology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Ewers
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany. .,Biomedical Center, Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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114
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Shigemoto-Mogami Y, Sato K. [Microglia and cellular differentiation - possibility of microglia as drug discovery target]. Nihon Yakurigaku Zasshi 2017; 150:268-274. [PMID: 29225288 DOI: 10.1254/fpj.150.268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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115
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Tang M, Reitz C. Genetics of Alzheimer's disease: an update. FUTURE NEUROLOGY 2017. [DOI: 10.2217/fnl-2017-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is clear that late-onset Alzheimer's disease (AD), the most common form of dementia in western societies, has a significant genetic component. The recent technological advances in high-throughput genome technologies have enabled the identification of more than 20 novel susceptibility loci. These findings have significantly advanced the understanding of the molecular mechanisms potentially underlying AD etiology, and have therefore provided valuable information for the development of targets for genetic testing, prevention and treatment. This article reviews these recent findings in AD genomics and discusses their implications for understanding the molecular underpinnings of the disease.
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Affiliation(s)
- Min Tang
- The Gertrude H Sergievsky Center, Columbia University, 630 West 168th Street, NY 10032, USA
| | - Christiane Reitz
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, 630 West 168th Street, NY 10032, USA
- The Gertrude H Sergievsky Center, Columbia University, 630 West 168th Street, NY 10032, USA
- The Department of Neurology, Columbia University, NY 10032, USA
- The Department of Epidemiology, Columbia University, NY 10032, USA
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116
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Intracellular trafficking of TREM2 is regulated by presenilin 1. Exp Mol Med 2017; 49:e405. [PMID: 29611543 PMCID: PMC5750471 DOI: 10.1038/emm.2017.200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/05/2017] [Accepted: 05/31/2017] [Indexed: 01/26/2023] Open
Abstract
Genetic mutations in triggering receptor expressed on myeloid cells 2 (TREM2) have been linked to a variety of neurodegenerative diseases including Alzheimer's disease, amyotrophic lateral sclerosis, frontotemporal dementia and Parkinson's disease. In the brain, TREM2 is highly expressed on the cell surface of microglia, where it can transduce signals to regulate microglial functions such as phagocytosis. To date, mechanisms underlying intracellular trafficking of TREM2 remain elusive. Mutations in the presenilin 1 (PS1) catalytic subunit of the γ-secretase complex have been associated with increased generation of the amyloidogenic Aβ (amyloid-β) 42 peptide through cleavage of the Aβ precursor amyloid precursor protein. Here we found that TREM2 interacts with PS1 in a manner independent of γ-secretase activity. Mutations in TREM2 alter its subcellular localization and affects its interaction with PS1. Upregulation of PS1 reduces, whereas downregulation of PS1 increases, steady-state levels of cell surface TREM2. Furthermore, PS1 overexpression results in attenuated phagocytic uptake of Aβ by microglia, which is reversed by TREM2 overexpression. Our data indicate a novel role for PS1 in regulating TREM2 intracellular trafficking and pathophysiological function.
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117
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Fahrenhold M, Rakic S, Classey J, Brayne C, Ince PG, Nicoll JAR, Boche D. TREM2 expression in the human brain: a marker of monocyte recruitment? Brain Pathol 2017; 28:595-602. [PMID: 28987033 PMCID: PMC6221091 DOI: 10.1111/bpa.12564] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/02/2017] [Indexed: 01/04/2023] Open
Abstract
Mutation in the triggering receptor expressed on myeloid cells (TREM) 2 gene has been identified as a risk factor for several neurodegenerative diseases including Alzheimer's disease (AD). Experimental studies using animal models of AD have highlighted a number of functions associated with TREM2 and its expression by microglial cells. It has therefore been assumed that this is also the case in humans. However, there is very limited information concerning the cellular expression of TREM2 in the human brain. As part of investigations of microglia using post‐mortem resources provided by the Medical Research Council Cognitive Function and Ageing Studies (MRC‐CFAS), we immunostained the cerebral cortex of 299 participants for TREM2 using the Sigma antibody HPA010917 and compared with the macrophage/microglial markers Iba1 and CD68. As expected, Iba1 and CD68 labeled microglia and perivascular macrophages. However, in most cases (284/299), the TREM2 antibody labelled monocytes within vascular lumens, but not microglia or perivascular macrophages. In contrast, in 5 out of 6 cases with acute infarcts, TREM2 immunoreaction identified cells within the brain parenchyma interpreted as recruited monocytes. Six cases with old infarcts contained phagocytic foamy macrophages which were CD68‐positive but TREM2 negative. Our observations, using the HPA010917 anti‐TREM2 antibody, suggest that TREM2 is not expressed by microglia but instead seems to be a marker of recruited monocytes in the human brain. This finding has implications with regards to the role of TREM2 as a risk factor, emphasizing the importance of systemic immune responses in the development and progression of Alzheimer's disease.
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Affiliation(s)
- Marie Fahrenhold
- Clinical Neurosciences, Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Sonja Rakic
- Clinical Neurosciences, Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - John Classey
- Clinical Neurosciences, Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Carol Brayne
- Cambridge Institute of Public Health, Department of Public Health and Primary Care, University of Cambridge, Cambridge, CB1 8RN, UK
| | - Paul G Ince
- Sheffield Institute for Translational Neuroscience, Sheffield University, Sheffield, S10 2HQ, UK
| | - James A R Nicoll
- Clinical Neurosciences, Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK.,Department of Cellular Pathology, University Hospital Southampton NHS Foundation Trust, Southampton, Southampton SO16 6YD, UK
| | - Delphine Boche
- Clinical Neurosciences, Clinical and Experimental Sciences Academic Unit, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
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118
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Bemiller SM, McCray TJ, Allan K, Formica SV, Xu G, Wilson G, Kokiko-Cochran ON, Crish SD, Lasagna-Reeves CA, Ransohoff RM, Landreth GE, Lamb BT. TREM2 deficiency exacerbates tau pathology through dysregulated kinase signaling in a mouse model of tauopathy. Mol Neurodegener 2017; 12:74. [PMID: 29037207 PMCID: PMC5644120 DOI: 10.1186/s13024-017-0216-6] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/09/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genetic variants of the Triggering Receptor Expressed on Myeloid Cells-2 (TREM2) confer increased risk of developing late-onset Alzheimer's Disease (LOAD) and other neurodegenerative disorders. Recent studies provided insight into the multifaceted roles of TREM2 in regulating extracellular β-amyloid (Aβ) pathology, myeloid cell accumulation, and inflammation observed in AD, yet little is known regarding the role of TREM2 in regulating intracellular microtubule associated protein tau (MAPT; tau) pathology in neurodegenerative diseases and in AD, in particular. RESULTS Here we report that TREM2 deficiency leads to accelerated and exacerbated hyperphosphorylation and aggregation of tau in a humanized mouse model of tauopathy. TREM2 deficiency also results, indirectly, in dramatic widespread dysregulation of neuronal stress kinase pathways. CONCLUSIONS Our results suggest that deficiency of microglial TREM2 leads to heightened tau pathology coupled with widespread increases in activated neuronal stress kinases. These findings offer new insight into the complex, multiple roles of TREM2 in regulating Aβ and tau pathologies.
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Affiliation(s)
- Shane M Bemiller
- Department of Neurosciences, The Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
- Kent State University, School of Biomedical Sciences, Kent, OH, USA.
- Indiana University School of Medicine Stark Neuroscience Research Institute, Indianapolis, IN, USA.
| | - Tyler J McCray
- Indiana University School of Medicine Stark Neuroscience Research Institute, Indianapolis, IN, USA
| | - Kevin Allan
- Department of Neurosciences, Case Western Reserve University, Cleveland, USA
| | - Shane V Formica
- Department of Neurosciences, The Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | - Guixiang Xu
- Department of Neurosciences, The Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
- Indiana University School of Medicine Stark Neuroscience Research Institute, Indianapolis, IN, USA
| | - Gina Wilson
- Department of Neurosciences, Northeastern Ohio Medical University, Rootstown, OH, USA
| | - Olga N Kokiko-Cochran
- Department of Neurosciences, The Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
- Department of Neurosciences, The Ohio State University, Columbus, OH, USA
| | - Samuel D Crish
- Department of Neurosciences, Northeastern Ohio Medical University, Rootstown, OH, USA
| | | | | | - Gary E Landreth
- Indiana University School of Medicine Stark Neuroscience Research Institute, Indianapolis, IN, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, USA
| | - Bruce T Lamb
- Department of Neurosciences, The Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
- Indiana University School of Medicine Stark Neuroscience Research Institute, Indianapolis, IN, USA.
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119
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Let's make microglia great again in neurodegenerative disorders. J Neural Transm (Vienna) 2017; 125:751-770. [PMID: 29027011 DOI: 10.1007/s00702-017-1792-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 09/18/2017] [Indexed: 12/12/2022]
Abstract
All of the common neurodegenerative disorders-Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and prion diseases-are characterized by accumulation of misfolded proteins that trigger activation of microglia; brain-resident mononuclear phagocytes. This chronic form of neuroinflammation is earmarked by increased release of myriad cytokines and chemokines in patient brains and biofluids. Microglial phagocytosis is compromised early in the disease process, obfuscating clearance of abnormal proteins. This review identifies immune pathologies shared by the major neurodegenerative disorders. The overarching concept is that aberrant innate immune pathways can be targeted for return to homeostasis in hopes of coaxing microglia into clearing neurotoxic misfolded proteins.
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120
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Kizuka Y, Kitazume S, Taniguchi N. N -glycan and Alzheimer's disease. Biochim Biophys Acta Gen Subj 2017; 1861:2447-2454. [DOI: 10.1016/j.bbagen.2017.04.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 04/27/2017] [Accepted: 04/27/2017] [Indexed: 12/14/2022]
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121
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Jay TR, von Saucken VE, Landreth GE. TREM2 in Neurodegenerative Diseases. Mol Neurodegener 2017; 12:56. [PMID: 28768545 PMCID: PMC5541421 DOI: 10.1186/s13024-017-0197-5] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 07/20/2017] [Indexed: 12/12/2022] Open
Abstract
TREM2 variants have been identified as risk factors for Alzheimer's disease (AD) and other neurodegenerative diseases (NDDs). Because TREM2 encodes a receptor exclusively expressed on immune cells, identification of these variants conclusively demonstrates that the immune response can play an active role in the pathogenesis of NDDs. These TREM2 variants also confer the highest risk for developing Alzheimer's disease of any risk factor identified in nearly two decades, suggesting that understanding more about TREM2 function could provide key insights into NDD pathology and provide avenues for novel immune-related NDD biomarkers and therapeutics. The expression, signaling and function of TREM2 in NDDs have been extensively investigated in an effort to understand the role of immune function in disease pathogenesis and progression. We provide a comprehensive review of our current understanding of TREM2 biology, including new insights into the regulation of TREM2 expression, and TREM2 signaling and function across NDDs. While many open questions remain, the current body of literature provides clarity on several issues. While it is still often cited that TREM2 expression is decreased by pro-inflammatory stimuli, it is now clear that this is true in vitro, but inflammatory stimuli in vivo almost universally increase TREM2 expression. Likewise, while TREM2 function is classically described as promoting an anti-inflammatory phenotype, more than half of published studies demonstrate a pro-inflammatory role for TREM2, suggesting that its role in inflammation is much more complex. Finally, these components of TREM2 biology are applied to a discussion of how TREM2 impacts NDD pathologies and the latest assessment of how these findings might be applied to immune-directed clinical biomarkers and therapeutics.
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Affiliation(s)
- Taylor R. Jay
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
| | - Victoria E. von Saucken
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
| | - Gary E. Landreth
- Department of Neurosciences, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106 USA
- Stark Neurosciences Research Institute, Indiana University School of Medicine, 320 W 15th Street, Indianapolis, IN 46202 USA
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122
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Lall D, Baloh RH. Microglia and C9orf72 in neuroinflammation and ALS and frontotemporal dementia. J Clin Invest 2017; 127:3250-3258. [PMID: 28737506 DOI: 10.1172/jci90607] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a degenerative disorder that is characterized by loss of motor neurons and shows clinical, pathological, and genetic overlap with frontotemporal dementia (FTD). Activated microglia are a universal feature of ALS/FTD pathology; however, their role in disease pathogenesis remains incompletely understood. The recent discovery that ORF 72 on chromosome 9 (C9orf72), the gene most commonly mutated in ALS/FTD, has an important role in myeloid cells opened the possibility that altered microglial function plays an active role in disease. This Review highlights the contribution of microglia to ALS/FTD pathogenesis, discusses the connection between autoimmunity and ALS/FTD, and explores the possibility that C9orf72 and other ALS/FTD genes may have a "dual effect" on both neuronal and myeloid cell function that could explain a shared propensity for altered systemic immunity and neurodegeneration.
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Affiliation(s)
- Deepti Lall
- Board of Governors Regenerative Medicine Institute and
| | - Robert H Baloh
- Board of Governors Regenerative Medicine Institute and.,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
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123
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Abstract
Prion diseases are a group of progressive and fatal neurodegenerative disorders characterized by deposition of scrapie prion protein (PrPSc) in the CNS. This deposition is accompanied by neuronal loss, spongiform change, astrogliosis, and conspicuous microglial activation. Here, we argue that microglia play an overall neuroprotective role in prion pathogenesis. Several microglia-related molecules, such as Toll-like receptors (TLRs), the complement system, cytokines, chemokines, inflammatory regulators, and phagocytosis mediators, are involved in prion pathogenesis. However, the molecular mechanisms underlying the microglial response to prion infection are largely unknown. Consequently, we lack a comprehensive understanding of the regulatory network of microglial activation. On the positive side, recent findings suggest that therapeutic strategies modulating microglial activation and function may have merit in prion disease. Moreover, studies on the role of microglia in prion disease could deepen our understanding of neuroinflammation in a broad range of neurodegenerative disorders.
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124
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TREM2/DAP12 Signal Elicits Proinflammatory Response in Microglia and Exacerbates Neuropathic Pain. J Neurosci 2017; 36:11138-11150. [PMID: 27798193 DOI: 10.1523/jneurosci.1238-16.2016] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/12/2016] [Indexed: 11/21/2022] Open
Abstract
Neuropathic pain afflicts millions of people, and the development of an effective treatment for this intractable pain is an urgent issue. Recent evidence has implicated microglia in neuropathic pain. The present study showed that the DNAX-activating protein of 12 kDa (DAP12) and its associated "triggering receptor expressed on myeloid cells 2" (TREM2) were predominantly expressed by microglia in the dorsal horn after spinal nerve injury, revealing a role for TREM2/DAP12 signaling in neuropathic pain. Nerve injury-induced proinflammatory cytokine expression in microglia and pain behaviors were significantly suppressed in Dap12-deficient mice. Furthermore, intrathecal administration of TREM2 agonistic antibody induced proinflammatory cytokine expression, as well as neuropathic pain, in mice without nerve injury. The agonistic antibody induced proinflammatory responses and neuropathic pain was not observed in Dap12-deficient mice. Together, these results suggest that TREM2/DAP12-mediated signals in microglia exacerbate nerve injury-induced neuropathic pain by inducing proinflammatory cytokine secretion from microglia. Suppression of DAP12-mediated signals could be a therapeutic target for neuropathic pain. SIGNIFICANCE STATEMENT Recent studies have revealed that activated microglia in the spinal dorsal horn exacerbate neuropathic pain, which has suggested that suppression of microglial activity should be considered as a therapeutic target. However, only a few molecules have been identified as regulators of microglial activity. In this study, we focused on a receptor complex of TREM2 and DAP12, both of which are expressed by microglia and have been implicated in the pathogenesis of Alzheimer's disease, and demonstrated that TREM2/DAP12 signaling promoted proinflammatory responses in microglia and exacerbates neuropathic pain. The present results revealed the functional significance of TREM2/DAP12 signaling in microglial activation after neuronal injury, and could help in the development of treatments for neuropathic pain and neurodegenerative diseases.
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125
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Genetic variation associated with the occurrence and progression of neurological disorders. Neurotoxicology 2017; 61:243-264. [DOI: 10.1016/j.neuro.2016.09.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023]
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126
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Obst J, Simon E, Mancuso R, Gomez-Nicola D. The Role of Microglia in Prion Diseases: A Paradigm of Functional Diversity. Front Aging Neurosci 2017; 9:207. [PMID: 28690540 PMCID: PMC5481309 DOI: 10.3389/fnagi.2017.00207] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/09/2017] [Indexed: 12/26/2022] Open
Abstract
Inflammation is a major component of neurodegenerative diseases. Microglia are the innate immune cells in the central nervous system (CNS). In the healthy brain, microglia contribute to tissue homeostasis and regulation of synaptic plasticity. Under disease conditions, they play a key role in the development and maintenance of the neuroinflammatory response, by showing enhanced proliferation and activation. Prion diseases are progressive chronic neurodegenerative disorders associated with the accumulation of the scrapie prion protein PrPSc, a misfolded conformer of the cellular prion protein PrPC. This review article provides the current knowledge on the role of microglia in the pathogenesis of prion disease. A large body of evidence shows that microglia can trigger neurotoxic pathways contributing to progressive degeneration. Yet, microglia are also crucial for controlling inflammatory, repair and regenerative processes. This dual role of microglia is regulated by multiple pathways and evidences the ability of these cells to polarize into distinct phenotypes with characteristic functions. The awareness that the neuroinflammatory response is inextricably involved in producing tissue damage as well as repair in neurodegenerative disorders, opens new perspectives for the modulation of the immune system. A better understanding of this complex process will be essential for developing effective therapies for neurodegenerative diseases, in order to improve the quality of life of patients and mitigating the personal, economic and social consequences derived from these diseases.
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Affiliation(s)
- Juliane Obst
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Emilie Simon
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Renzo Mancuso
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
| | - Diego Gomez-Nicola
- Biological Sciences, University of Southampton, Southampton General HospitalSouthampton, United Kingdom
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127
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Arcuri C, Mecca C, Bianchi R, Giambanco I, Donato R. The Pathophysiological Role of Microglia in Dynamic Surveillance, Phagocytosis and Structural Remodeling of the Developing CNS. Front Mol Neurosci 2017; 10:191. [PMID: 28674485 PMCID: PMC5474494 DOI: 10.3389/fnmol.2017.00191] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/30/2017] [Indexed: 12/13/2022] Open
Abstract
In vertebrates, during an early wave of hematopoiesis in the yolk sac between embryonic day E7.0 and E9.0, cells of mesodermal leaflet addressed to macrophage lineage enter in developing central nervous system (CNS) and originate the developing native microglial cells. Depending on the species, microglial cells represent 5–20% of glial cells resident in adult brain. Here, we briefly discuss some canonical functions of the microglia, i.e., cytokine secretion and functional transition from M1 to M2 phenotype. In addition, we review studies on the non-canonical functions of microglia such as regulation of phagocytosis, synaptic pruning, and sculpting postnatal neural circuits. In this latter context the contribution of microglia to some neurodevelopmental disorders is now well established. Nasu-Hakola (NHD) disease is considered a primary microgliopathy with alterations of the DNAX activation protein 12 (DAP12)-Triggering receptor expressed on myeloid cells 2 (TREM-2) signaling and removal of macromolecules and apoptotic cells followed by secondary microglia activation. In Rett syndrome Mecp2-/- microglia shows a substantial impairment of phagocytic ability, although the role of microglia is not yet clear. In a mouse model of Tourette syndrome (TS), microglia abnormalities have also been described, and deficient microglia-mediated neuroprotection is obvious. Here we review the role of microglial cells in neurodevelopmental disorders without inflammation and on the complex role of microglia in developing CNS.
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Affiliation(s)
- Cataldo Arcuri
- Department of Experimental Medicine, Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of PerugiaPerugia, Italy
| | - Carmen Mecca
- Department of Experimental Medicine, Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of PerugiaPerugia, Italy
| | - Roberta Bianchi
- Department of Experimental Medicine, Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of PerugiaPerugia, Italy
| | - Ileana Giambanco
- Department of Experimental Medicine, Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of PerugiaPerugia, Italy
| | - Rosario Donato
- Department of Experimental Medicine, Centro Universitario per la Ricerca sulla Genomica Funzionale, Perugia Medical School, University of PerugiaPerugia, Italy
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128
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Giannoccaro MP, Bartoletti-Stella A, Piras S, Pession A, De Massis P, Oppi F, Stanzani-Maserati M, Pasini E, Baiardi S, Avoni P, Parchi P, Liguori R, Capellari S. Multiple variants in families with amyotrophic lateral sclerosis and frontotemporal dementia related to C9orf72 repeat expansion: further observations on their oligogenic nature. J Neurol 2017. [PMID: 28620717 DOI: 10.1007/s00415-017-8540-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The C9orf72 repeat expansion (RE) is one of the most frequent causative mutations of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, it is still unclear how the C9orf72 RE can lead to a heterogeneous phenotype. Several reports have shown the coexistence of mutations in multiple ALS/FTD causative genes in the same family, suggesting an oligogenic etiology for ALS and FTD. Our aim was to investigate this phenomenon in an Italian group of ALS/FTD pedigrees carrying the C9orf72 RE. We included 11 subjects from 11 pedigrees with ALS/FTD and the C9orf72 RE. Mutation screening of FUS, SOD1 and TARDBP genes was performed by direct sequencing. A dementia-specific custom-designed targeted next-generation sequencing panel was used for screening dementia-associated genes mutations. We found genetic variants in additional ALS or dementia-related genes in four pedigrees, including the p.V47A variant in the TYROBP gene. As a group, double mutation carriers displayed a tendency toward a younger age at onset and a higher frequency of positive familiar history and of parkinsonism. Our observation supports the hypothesis that the co-presence of mutations in different genes may be relevant for the clinical expression of ALS/FTD and of their oligogenic nature.
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Affiliation(s)
- Maria Pia Giannoccaro
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.
| | - Anna Bartoletti-Stella
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,Dipartimento Neuroscienze, psicologia, area del farmaco e salute del bambino, Università di Firenze, Firenze, Italy
| | - Silvia Piras
- IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | - Annalisa Pession
- UOC Anatomia patologica, Dipartimento di Scienze Oncologiche, via Altura, 3, 40136, Bologna, Italy
| | | | - Federico Oppi
- IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | | | - Elena Pasini
- IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | - Simone Baiardi
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
| | - Patrizia Avoni
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | - Piero Parchi
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | - Rocco Liguori
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy
| | - Sabina Capellari
- UOC Clinica Neurologica, Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy. .,IRCCS Istituto delle Scienze Neurologiche, UOC Clinica Neurologica, Ospedale Bellaria, via Altura, 3, Bologna, Italy.
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129
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Yeh FL, Hansen DV, Sheng M. TREM2, Microglia, and Neurodegenerative Diseases. Trends Mol Med 2017; 23:512-533. [DOI: 10.1016/j.molmed.2017.03.008] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 02/15/2017] [Accepted: 03/26/2017] [Indexed: 01/17/2023]
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130
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Pinto S, Cunha C, Barbosa M, Vaz AR, Brites D. Exosomes from NSC-34 Cells Transfected with hSOD1-G93A Are Enriched in miR-124 and Drive Alterations in Microglia Phenotype. Front Neurosci 2017; 11:273. [PMID: 28567000 PMCID: PMC5434170 DOI: 10.3389/fnins.2017.00273] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/28/2017] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal adult-onset neurodegenerative disorder affecting motor neurons (MNs). Evidences indicate that ALS is a non-cell autonomous disease in which glial cells participate in both disease onset and progression. Exosomal transfer of mutant copper-zinc superoxide dismutase 1 (mSOD1) from cell-to-cell was suggested to contribute to disease dissemination. Data from our group and others showed that exosomes from activated cells contain inflammatory-related microRNAs (inflamma-miRNAs) that recapitulate the donor cell. While glia-derived exosomes and their effects in neurons have been addressed by several studies, only a few investigated the influence of motor neuron (MN)-derived exosomes in other cell function, the aim of the present study. We assessed a set of inflamma-miRs in NSC-34 MN-like cells transfected with mutant SOD1(G93A) and extended the study into their derived exosomes (mSOD1 exosomes). Then, the effects produced by mSOD1 exosomes in the activation and polarization of the recipient N9 microglial cells were investigated. Exosomes in coculture with N9 microglia and NSC-34 cells [either transfected with either wild-type (wt) human SOD1 or mutant SOD1(G93A)] showed to be transferred into N9 cells. Increased miR-124 expression was found in mSOD1 NSC-34 cells and in their derived exosomes. Incubation of mSOD1 exosomes with N9 cells determined a sustained 50% reduction in the cell phagocytic ability. It also caused a persistent NF-kB activation and an acute generation of NO, MMP-2, and MMP-9 activation, as well as upregulation of IL-1β, TNF-α, MHC-II, and iNOS gene expression, suggestive of induced M1 polarization. Marked elevation of IL-10, Arginase 1, TREM2, RAGE, and TLR4 mRNA levels, together with increased miR-124, miR-146a, and miR-155, at 24 h incubation, suggest the switch to mixed M1 and M2 subpopulations in the exosome-treated N9 microglial cells. Exosomes from mSOD1 NSC-34 MNs also enhanced the number of senescent-like positive N9 cells. Data suggest that miR-124 is translocated from the mSOD1 MNs to exosomes, which determine early and late phenotypic alterations in the recipient N9-microglial cells. In conclusion, modulation of the inflammatory-associated miR-124, in mSOD1 NSC-34 MNs, with potential benefits in the cargo of their exosomes may reveal a promising therapeutic strategy in halting microglia activation and associated effects in MN degeneration.
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Affiliation(s)
- Sara Pinto
- Neuron Glia Biology in Health and Disease, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal
| | - Carolina Cunha
- Neuron Glia Biology in Health and Disease, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal
| | - Marta Barbosa
- Neuron Glia Biology in Health and Disease, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal
| | - Ana R Vaz
- Neuron Glia Biology in Health and Disease, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal.,Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal
| | - Dora Brites
- Neuron Glia Biology in Health and Disease, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal.,Department of Biochemistry and Human Biology, Faculty of Pharmacy, Universidade de LisboaLisbon, Portugal
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131
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Varnum MM, Clayton KA, Yoshii-Kitahara A, Yonemoto G, Koro L, Ikezu S, Ikezu T. A split-luciferase complementation, real-time reporting assay enables monitoring of the disease-associated transmembrane protein TREM2 in live cells. J Biol Chem 2017; 292:10651-10663. [PMID: 28490631 DOI: 10.1074/jbc.m116.759159] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 04/20/2017] [Indexed: 12/18/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a single transmembrane molecule uniquely expressed in microglia. TREM2 mutations are genetically linked to Nasu-Hakola disease and associated with multiple neurodegenerative disorders, including Alzheimer's disease. TREM2 may regulate microglial inflammation and phagocytosis through coupling to the adaptor protein TYRO protein-tyrosine kinase-binding protein (TYROBP). However, there is no functional system for monitoring this protein-protein interaction. We developed a luciferase-based modality for real-time monitoring of TREM2-TYROBP coupling in live cells that utilizes split-luciferase complementation technology based on TREM2 and TYROBP fusion to the C- or N-terminal portion of the Renilla luciferase gene. Transient transfection of human embryonic kidney 293 cells with this reporter vector increased luciferase activity upon stimulation with an anti-TREM2 antibody, which induces their homodimerization. This was confirmed by ELISA-based analysis of the TREM2-TYROBP interaction. Antibody-mediated TREM2 stimulation enhanced spleen tyrosine kinase (SYK) activity and uptake of Staphylococcus aureus in microglial cell line BV-2 in a kinase-dependent manner. Interestingly, the TREM2 T66M mutation significantly enhanced luciferase activity without stimulation, indicating constitutive coupling to TYROBP. Finally, flow cytometry analyses indicated significantly lower surface expression of T66M TREM2 variant than wild type or other TREM2 variants. These results demonstrate that our TREM2 reporter vector is a novel tool for monitoring the TREM2-TYROBP interaction in real time.
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Affiliation(s)
- Megan M Varnum
- From the Departments of Pharmacology and Experimental Therapeutics and
| | - Kevin A Clayton
- From the Departments of Pharmacology and Experimental Therapeutics and
| | | | - Grant Yonemoto
- From the Departments of Pharmacology and Experimental Therapeutics and
| | - Lacin Koro
- From the Departments of Pharmacology and Experimental Therapeutics and
| | - Seiko Ikezu
- From the Departments of Pharmacology and Experimental Therapeutics and
| | - Tsuneya Ikezu
- From the Departments of Pharmacology and Experimental Therapeutics and .,Neurology, Boston University School of Medicine, Boston, Massachusetts 02118
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132
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Mazaheri F, Snaidero N, Kleinberger G, Madore C, Daria A, Werner G, Krasemann S, Capell A, Trümbach D, Wurst W, Brunner B, Bultmann S, Tahirovic S, Kerschensteiner M, Misgeld T, Butovsky O, Haass C. TREM2 deficiency impairs chemotaxis and microglial responses to neuronal injury. EMBO Rep 2017; 18:1186-1198. [PMID: 28483841 DOI: 10.15252/embr.201743922] [Citation(s) in RCA: 218] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
Abstract
Sequence variations in the triggering receptor expressed on myeloid cells 2 (TREM2) have been linked to an increased risk for neurodegenerative disorders such as Alzheimer's disease and frontotemporal lobar degeneration. In the brain, TREM2 is predominantly expressed in microglia. Several disease-associated TREM2 variants result in a loss of function by reducing microglial phagocytosis, impairing lipid sensing, preventing binding of lipoproteins and affecting shielding of amyloid plaques. We here investigate the consequences of TREM2 loss of function on the microglia transcriptome. Among the differentially expressed messenger RNAs in wild-type and Trem2-/- microglia, gene clusters are identified which represent gene functions in chemotaxis, migration and mobility. Functional analyses confirm that loss of TREM2 impairs appropriate microglial responses to injury and signals that normally evoke chemotaxis on multiple levels. In an ex vivo organotypic brain slice assay, absence of TREM2 reduces the distance migrated by microglia. Moreover, migration towards defined chemo-attractants is reduced upon ablation of TREM2 and can be rescued by TREM2 re-expression. In vivo, microglia lacking TREM2 migrate less towards injected apoptotic neurons, and outgrowth of microglial processes towards sites of laser-induced focal CNS damage in the somatosensory cortex is slowed. The apparent lack of chemotactic stimulation upon depletion of TREM2 is consistent with a stable expression profile of genes characterizing the homoeostatic signature of microglia.
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Affiliation(s)
- Fargol Mazaheri
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Nicolas Snaidero
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Institute for Clinical Neuroimmunology, Biomedical Center (BMC) and University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gernot Kleinberger
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Charlotte Madore
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Anna Daria
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Georg Werner
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Susanne Krasemann
- Institute for Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anja Capell
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Dietrich Trümbach
- Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Wolfgang Wurst
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Developmental Genetics, Technical University Munich-Weihenstephan, Neuherberg, Germany
| | - Bettina Brunner
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Sebastian Bultmann
- Department of Biology and Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians-Universität München, Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Martin Kerschensteiner
- Institute for Clinical Neuroimmunology, Biomedical Center (BMC) and University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Misgeld
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
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133
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Kober DL, Brett TJ. TREM2-Ligand Interactions in Health and Disease. J Mol Biol 2017; 429:1607-1629. [PMID: 28432014 DOI: 10.1016/j.jmb.2017.04.004] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 01/04/2023]
Abstract
The protein triggering receptor expressed on myeloid cells-2 (TREM2) is an immunomodulatory receptor with a central role in myeloid cell activation and survival. In recent years, the importance of TREM2 has been highlighted by the identification of coding variants that increase risk for Alzheimer's disease and other neurodegenerative diseases. Animal studies have further shown the importance of TREM2 in neurodegenerative and other inflammatory disease models including chronic obstructive pulmonary disease, multiple sclerosis, and stroke. A mechanistic understanding of TREM2 function remains elusive, however, due in part to the absence of conclusive information regarding the identity of endogenous TREM2 ligands. While many TREM2 ligands have been proposed, their physiological role and mechanism of engagement remain to be determined. In this review, we highlight the suggested roles of TREM2 in these diseases and the recent advances in our understanding of TREM2 and discuss putative TREM2-ligand interactions and their potential roles in signaling during health and disease. We develop a model based on the TREM2 structure to explain how different TREM2 ligands might interact with the receptor and how disease risk variants may alter ligand interactions. Finally, we propose future experimental directions to establish the role and importance of these different interactions on TREM2 function.
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Affiliation(s)
- Daniel L Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tom J Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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134
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Ulrich JD, Ulland TK, Colonna M, Holtzman DM. Elucidating the Role of TREM2 in Alzheimer’s Disease. Neuron 2017; 94:237-248. [DOI: 10.1016/j.neuron.2017.02.042] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 12/20/2022]
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135
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Jendresen C, Årskog V, Daws MR, Nilsson LNG. The Alzheimer's disease risk factors apolipoprotein E and TREM2 are linked in a receptor signaling pathway. J Neuroinflammation 2017; 14:59. [PMID: 28320424 PMCID: PMC5360024 DOI: 10.1186/s12974-017-0835-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/07/2017] [Indexed: 11/19/2022] Open
Abstract
Background Triggering receptor expressed on myeloid cells 2 (TREM2) and apolipoprotein E (APOE) are genetically linked to Alzheimer’s disease. Here, we investigated whether human ApoE mediates signal transduction through human and murine TREM2 and sought to identify a TREM2-binding domain in human ApoE. Methods To investigate cell signaling through TREM2, a cell line was used which expressed an NFAT-inducible β-galactosidase reporter and human or murine TREM2, fused to CD8 transmembrane and CD3ζ intracellular signaling domains. ELISA-based binding assays were used to determine binding affinities of human ApoE isoforms to human TREM2 and to identify a TREM2-binding domain in ApoE. Results ApoE was found to be an agonist to human TREM2 with EC50 in the low nM range, and to murine TREM2 with reduced potency. In the reporter cells, TREM2 expression was lower than in nontransgenic mouse brain. Human ApoE isoforms ε2, ε3, and ε4 bound to human TREM2 with Kd in the low nM range. The binding was displaced by an ApoE-mimetic peptide (amino acids 130–149). Conclusions An ApoE-mediated dose-dependent signal transduction through TREM2 in reporter cells was demonstrated, and a TREM2-binding region in ApoE was identified. The relevance of an ApoE-TREM2 receptor signaling pathway to Alzheimer’s disease is discussed. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0835-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Charlotte Jendresen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway
| | - Vibeke Årskog
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway
| | - Michael R Daws
- Division of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Lars N G Nilsson
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway.
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136
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Cooper-Knock J, Green C, Altschuler G, Wei W, Bury JJ, Heath PR, Wyles M, Gelsthorpe C, Highley JR, Lorente-Pons A, Beck T, Doyle K, Otero K, Traynor B, Kirby J, Shaw PJ, Hide W. A data-driven approach links microglia to pathology and prognosis in amyotrophic lateral sclerosis. Acta Neuropathol Commun 2017; 5:23. [PMID: 28302159 PMCID: PMC5353945 DOI: 10.1186/s40478-017-0424-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/06/2017] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that lacks a predictive and broadly applicable biomarker. Continued focus on mutation-specific upstream mechanisms has yet to predict disease progression in the clinic. Utilising cellular pathology common to the majority of ALS patients, we implemented an objective transcriptome-driven approach to develop noninvasive prognostic biomarkers for disease progression. Genes expressed in laser captured motor neurons in direct correlation (Spearman rank correlation, p < 0.01) with counts of neuropathology were developed into co-expression network modules. Screening modules using three gene sets representing rate of disease progression and upstream genetic association with ALS led to the prioritisation of a single module enriched for immune response to motor neuron degeneration. Genes in the network module are important for microglial activation and predict disease progression in genetically heterogeneous ALS cohorts: Expression of three genes in peripheral lymphocytes - LILRA2, ITGB2 and CEBPD – differentiate patients with rapid and slowly progressive disease, suggesting promise as a blood-derived biomarker. TREM2 is a member of the network module and the level of soluble TREM2 protein in cerebrospinal fluid is shown to predict survival when measured in late stage disease (Spearman rank correlation, p = 0.01). Our data-driven systems approach has, for the first time, directly linked microglia to the development of motor neuron pathology. LILRA2, ITGB2 and CEBPD represent peripherally accessible candidate biomarkers and TREM2 provides a broadly applicable therapeutic target for ALS.
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137
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Owens R, Grabert K, Davies CL, Alfieri A, Antel JP, Healy LM, McColl BW. Divergent Neuroinflammatory Regulation of Microglial TREM Expression and Involvement of NF-κB. Front Cell Neurosci 2017; 11:56. [PMID: 28303091 PMCID: PMC5332401 DOI: 10.3389/fncel.2017.00056] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/15/2017] [Indexed: 12/28/2022] Open
Abstract
The triggering receptor expressed on myeloid cells (TREM) family of proteins are cell surface receptors with important roles in regulation of myeloid cell inflammatory activity. In the central nervous system, TREM2 is implicated in further roles in microglial homeostasis, neuroinflammation and neurodegeneration. Different TREM receptors appear to have contrasting roles in controlling myeloid immune activity therefore the relative and co-ordinated regulation of their expression is important to understand but is currently poorly understood. We sought to determine how microglial TREM expression is affected under neuroinflammatory conditions in vitro and in vivo. Our data show that microglial Trem1 and Trem2 gene expression are regulated in an opposing manner by lipopolysaccharide (LPS) in vitro in both adult murine and human microglia. LPS caused a significant induction of Trem1 and a contrasting suppression of Trem2 expression. We also observed similar divergent Trem1 and Trem2 responses in vivo in response to acute brain inflammation and acute cerebral ischaemia. Our data show that inhibition of NF-κB activation prevents the LPS-induced alterations in both Trem1 and Trem2 expression in vitro indicating NF-κB as a common signaling intermediate controlling these divergent responses. Distinct patterns of microglial Trem1 induction and Trem2 suppression to different Toll-like receptor (TLR) ligands were also evident, notably with Trem1 induction restricted to those ligands activating TLRs signaling via TRIF. Our data show co-ordinated but divergent regulation of microglial TREM receptor expression with a central role for NF-κB. Neuroinflammatory conditions that alter the balance in TREM expression could therefore be an important influence on microglial inflammatory and homeostatic activity with implications for neuroinflammatory and neurodegenerative disease.
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Affiliation(s)
- Rosie Owens
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
| | - Kathleen Grabert
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
| | - Claire L Davies
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
| | - Alessio Alfieri
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
| | - Jack P Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Luke M Healy
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Barry W McColl
- The Royal (Dick) School of Veterinary Studies, University of Edinburgh Midlothian, UK
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138
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Colonna M, Butovsky O. Microglia Function in the Central Nervous System During Health and Neurodegeneration. Annu Rev Immunol 2017; 35:441-468. [PMID: 28226226 DOI: 10.1146/annurev-immunol-051116-052358] [Citation(s) in RCA: 1303] [Impact Index Per Article: 186.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Microglia are resident cells of the brain that regulate brain development, maintenance of neuronal networks, and injury repair. Microglia serve as brain macrophages but are distinct from other tissue macrophages owing to their unique homeostatic phenotype and tight regulation by the central nervous system (CNS) microenvironment. They are responsible for the elimination of microbes, dead cells, redundant synapses, protein aggregates, and other particulate and soluble antigens that may endanger the CNS. Furthermore, as the primary source of proinflammatory cytokines, microglia are pivotal mediators of neuroinflammation and can induce or modulate a broad spectrum of cellular responses. Alterations in microglia functionality are implicated in brain development and aging, as well as in neurodegeneration. Recent observations about microglia ontogeny combined with extensive gene expression profiling and novel tools to study microglia biology have allowed us to characterize the spectrum of microglial phenotypes during development, homeostasis, and disease. In this article, we review recent advances in our understanding of the biology of microglia, their contribution to homeostasis, and their involvement in neurodegeneration. Moreover, we highlight the complexity of targeting microglia for therapeutic intervention in neurodegenerative diseases.
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Affiliation(s)
- Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110;
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115;
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139
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Güttsches AK, Brady S, Krause K, Maerkens A, Uszkoreit J, Eisenacher M, Schreiner A, Galozzi S, Mertens-Rill J, Tegenthoff M, Holton JL, Harms MB, Lloyd TE, Vorgerd M, Weihl CC, Marcus K, Kley RA. Proteomics of rimmed vacuoles define new risk allele in inclusion body myositis. Ann Neurol 2017; 81:227-239. [PMID: 28009083 DOI: 10.1002/ana.24847] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/22/2016] [Accepted: 12/11/2016] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Sporadic inclusion body myositis (sIBM) pathogenesis is unknown; however, rimmed vacuoles (RVs) are a constant feature. We propose to identify proteins that accumulate within RVs. METHODS RVs and intact myofibers were laser microdissected from skeletal muscle of 18 sIBM patients and analyzed by a sensitive mass spectrometry approach using label-free spectral count-based relative protein quantification. Whole exome sequencing was performed on 62 sIBM patients. Immunofluorescence was performed on patient and mouse skeletal muscle. RESULTS A total of 213 proteins were enriched by >1.5 -fold in RVs compared to controls and included proteins previously reported to accumulate in sIBM tissue or when mutated cause myopathies with RVs. Proteins associated with protein folding and autophagy were the largest group represented. One autophagic adaptor protein not previously identified in sIBM was FYCO1. Rare missense coding FYCO1 variants were present in 11.3% of sIBM patients compared with 2.6% of controls (p = 0.003). FYCO1 colocalized at RVs with autophagic proteins such as MAP1LC3 and SQSTM1 in sIBM and other RV myopathies. One FYCO1 variant protein had reduced colocalization with MAP1LC3 when expressed in mouse muscle. INTERPRETATION This study used an unbiased proteomic approach to identify RV proteins in sIBM that included a novel protein involved in sIBM pathogenesis. FYCO1 accumulates at RVs, and rare missense variants in FYCO1 are overrepresented in sIBM patients. These FYCO1 variants may impair autophagic function, leading to RV formation in sIBM patient muscle. FYCO1 functionally connects autophagic and endocytic pathways, supporting the hypothesis that impaired endolysosomal degradation underlies the pathogenesis of sIBM. Ann Neurol 2017;81:227-239.
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Affiliation(s)
- Anne-Katrin Güttsches
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Stefen Brady
- Department of Neurology, Southmead Hospital, Bristol, United Kingdom
| | - Kathryn Krause
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.,Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Alexandra Maerkens
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany.,Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Julian Uszkoreit
- Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Martin Eisenacher
- Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Anja Schreiner
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Sara Galozzi
- Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Janine Mertens-Rill
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Martin Tegenthoff
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Janice L Holton
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, United Kingdom.,Department of Molecular Neuroscience, Queen Square Brain Bank, UCL Institute of Neurology, London, United Kingdom
| | | | - Thomas E Lloyd
- Johns Hopkins University School of Medicine, Baltimore, MD
| | - Matthias Vorgerd
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Conrad C Weihl
- Department of Neurology and Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, MO
| | - Katrin Marcus
- Medizinisches Proteom-Center, Ruhr-University Bochum, Bochum, Germany
| | - Rudolf A Kley
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
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140
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A novel mutation in TREM2 gene causing Nasu-Hakola disease and review of the literature. Neurobiol Aging 2017; 53:194.e13-194.e22. [PMID: 28214109 DOI: 10.1016/j.neurobiolaging.2017.01.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 01/11/2017] [Indexed: 11/20/2022]
Abstract
Nasu-hakola disease (NHD) is a rare disease characterized by bone cysts and fractures, frontal lobe syndrome, and progressive presenile dementia. NHD may be the prototype of primary microglial disorders of the CNS or, as they have been coined, "microgliopathies". Mutations in TREM2 and TYROBP genes are known to cause NHD. Interestingly, recent evidence-associated rare genetic variants of TREM2 gene with increased risk of Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, and Parkinson's disease. Here, we report a 33-year-old Greek female with phenotype suggestive of NHD. Full gene sequencing of the TREM2 and TYROBP genes revealed a novel mutation in exon 2 of TREM2 gene, namely c.244G>T (p.W50C) and heterozygosity in the parents and her brother. This report extends the range of TREM2 mutations that cause NHD phenotype. In addition, we provide a comprehensive review of all reported in the literature TREM2 gene mutations and the respective wide spectrum of clinical manifestations that highlights the importance of considering TREM2 gene mutations in a variety of neurodegenerative phenotypes.
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141
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Park JS, Ji IJ, Kim DH, An HJ, Yoon SY. The Alzheimer's Disease-Associated R47H Variant of TREM2 Has an Altered Glycosylation Pattern and Protein Stability. Front Neurosci 2017; 10:618. [PMID: 28149270 PMCID: PMC5241589 DOI: 10.3389/fnins.2016.00618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 12/26/2016] [Indexed: 11/13/2022] Open
Abstract
The R47H coding variant of the triggering receptor expressed on myeloid cells-2 (TREM2) increases the risk of Alzheimer's disease (AD) similar to apolipoprotein E4. TREM2 R47H has recently been shown to have impaired binding to damage-associated lipid or apolipoprotein ligands. However, it is not known how this R47H variant affects the biochemical characteristics of TREM2 and alters the pathogenesis of AD. We previously reported that TREM2-R47H has a slightly different glycosylation pattern from wild-type. A more detailed characterization in our present study confirms that TREM2 R47H has an altered glycosylation pattern and reduced stability. TREM2 R47H shows different glycosylation profiles from analysis using monensin or kifunensine treatment which were confirmed by mass spectrometry. The solubility of TREM2 R47H and its cleaved products such as intracellular domain (ICD) is also decreased, increasing its proteasomal and lysosomal degradation. The different biochemical characteristics of TREM2 R47H, including glycosylation, solubility and processing, may offer insights into a future therapeutic strategy for AD.
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Affiliation(s)
- Ji-Seon Park
- Alzheimer's Disease Experts Lab, Asan Medical Center, University of Ulsan College of MedicineSeoul, South Korea; Department of Brain Science, University of Ulsan College of MedicineSeoul, South Korea; Bio-Medical Institute of Technology, University of Ulsan College of MedicineSeoul, South Korea; Cell Dysfunction Research Center, University of Ulsan College of MedicineSeoul, South Korea
| | - In Jung Ji
- Asia Glycomics Reference SiteDaejeon, South Korea; Graduate School of Analytical Science and Technology, Chungnam National UniversityDaejeon, South Korea
| | - Dong-Hou Kim
- Alzheimer's Disease Experts Lab, Asan Medical Center, University of Ulsan College of MedicineSeoul, South Korea; Department of Brain Science, University of Ulsan College of MedicineSeoul, South Korea; Bio-Medical Institute of Technology, University of Ulsan College of MedicineSeoul, South Korea; Cell Dysfunction Research Center, University of Ulsan College of MedicineSeoul, South Korea
| | - Hyun Joo An
- Asia Glycomics Reference SiteDaejeon, South Korea; Graduate School of Analytical Science and Technology, Chungnam National UniversityDaejeon, South Korea
| | - Seung-Yong Yoon
- Alzheimer's Disease Experts Lab, Asan Medical Center, University of Ulsan College of MedicineSeoul, South Korea; Department of Brain Science, University of Ulsan College of MedicineSeoul, South Korea; Bio-Medical Institute of Technology, University of Ulsan College of MedicineSeoul, South Korea; Cell Dysfunction Research Center, University of Ulsan College of MedicineSeoul, South Korea
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142
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Kober DL, Alexander-Brett JM, Karch CM, Cruchaga C, Colonna M, Holtzman MJ, Brett TJ. Neurodegenerative disease mutations in TREM2 reveal a functional surface and distinct loss-of-function mechanisms. eLife 2016; 5:e20391. [PMID: 27995897 PMCID: PMC5173322 DOI: 10.7554/elife.20391] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/28/2016] [Indexed: 01/09/2023] Open
Abstract
Genetic variations in the myeloid immune receptor TREM2 are linked to several neurodegenerative diseases. To determine how TREM2 variants contribute to these diseases, we performed structural and functional studies of wild-type and variant proteins. Our 3.1 Å TREM2 crystal structure revealed that mutations found in Nasu-Hakola disease are buried whereas Alzheimer's disease risk variants are found on the surface, suggesting that these mutations have distinct effects on TREM2 function. Biophysical and cellular methods indicate that Nasu-Hakola mutations impact protein stability and decrease folded TREM2 surface expression, whereas Alzheimer's risk variants impact binding to a TREM2 ligand. Additionally, the Alzheimer's risk variants appear to epitope map a functional surface on TREM2 that is unique within the larger TREM family. These findings provide a guide to structural and functional differences among genetic variants of TREM2, indicating that therapies targeting the TREM2 pathway should be tailored to these genetic and functional differences with patient-specific medicine approaches for neurodegenerative disorders.
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Affiliation(s)
- Daniel L Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, St. Louis, United States
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
| | - Jennifer M Alexander-Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
| | - Celeste M Karch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, United States
| | - Carlos Cruchaga
- Department of Psychiatry, Washington University School of Medicine, St. Louis, United States
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, United States
| | - Michael J Holtzman
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, United States
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, United States
| | - Thomas J Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, United States
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143
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Dendrou CA, McVean G, Fugger L. Neuroinflammation - using big data to inform clinical practice. Nat Rev Neurol 2016; 12:685-698. [PMID: 27857124 DOI: 10.1038/nrneurol.2016.171] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuroinflammation is emerging as a central process in many neurological conditions, either as a causative factor or as a secondary response to nervous system insult. Understanding the causes and consequences of neuroinflammation could, therefore, provide insight that is needed to improve therapeutic interventions across many diseases. However, the complexity of the pathways involved necessitates the use of high-throughput approaches to extensively interrogate the process, and appropriate strategies to translate the data generated into clinical benefit. Use of 'big data' aims to generate, integrate and analyse large, heterogeneous datasets to provide in-depth insights into complex processes, and has the potential to unravel the complexities of neuroinflammation. Limitations in data analysis approaches currently prevent the full potential of big data being reached, but some aspects of big data are already yielding results. The implementation of 'omics' analyses in particular is becoming routine practice in biomedical research, and neuroimaging is producing large sets of complex data. In this Review, we evaluate the impact of the drive to collect and analyse big data on our understanding of neuroinflammation in disease. We describe the breadth of big data that are leading to an evolution in our understanding of this field, exemplify how these data are beginning to be of use in a clinical setting, and consider possible future directions.
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Affiliation(s)
- Calliope A Dendrou
- Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, and MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Gil McVean
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, and Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Lars Fugger
- Oxford Centre for Neuroinflammation, Nuffield Department of Clinical Neurosciences, and MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
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144
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Role of Microglia in Neurological Disorders and Their Potentials as a Therapeutic Target. Mol Neurobiol 2016; 54:7567-7584. [DOI: 10.1007/s12035-016-0245-0] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 10/19/2016] [Indexed: 02/06/2023]
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145
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Yin J, Liu X, He Q, Zhou L, Yuan Z, Zhao S. Vps35-dependent recycling of Trem2 regulates microglial function. Traffic 2016; 17:1286-1296. [PMID: 27717139 DOI: 10.1111/tra.12451] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 01/03/2023]
Abstract
Triggering receptor expressed on myeloid cells 2 (Trem2), an immune-modulatory receptor, is preferentially expressed in microglia of central nervous system. Trem2 might be involved in the development of Alzheimer's disease (AD) through regulating the inflammatory responses and phagocytosis of microglia. However, the intracellular trafficking of Trem2 remains unclear. In this study, we showed that Trem2 in the plasma membrane underwent endocytosis and recycling. Trem2 is internalized in a clathrin-dependent manner and then recycled back to the plasma membrane through vacuolar protein sorting 35 (Vps35), the key component of cargo recognition core of retromer complex, but not Rab11. When Vps35 is knocked down, Trem2 accumulated in the lysosomes but was not degraded. More importantly, Vps35 deficiency leads to excessive lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression and IL-6 production, which can be abolished by Trem2 overexpression. Furthermore, R47H Trem2, an AD-associated mutant, failed to interact with Vps35 and became unstable compared with wild-type Trem2. Our study suggests that Vps35/retromer is responsible for recycling of Trem2 in the regulation of microglial function such as proinflammatory responses, whereas R47H mutation impairs Trem2 trafficking, which might contribute to AD.
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Affiliation(s)
- Jie Yin
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaocui Liu
- Qingdao Mental Health Center, Qingdao, China
| | - Qing He
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China
| | - Lujun Zhou
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Sino-Danish College, University of Chinese Academy of Sciences, Beijing, China
| | - Zengqiang Yuan
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, China
| | - Siqi Zhao
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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146
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Xiang X, Werner G, Bohrmann B, Liesz A, Mazaheri F, Capell A, Feederle R, Knuesel I, Kleinberger G, Haass C. TREM2 deficiency reduces the efficacy of immunotherapeutic amyloid clearance. EMBO Mol Med 2016; 8:992-1004. [PMID: 27402340 PMCID: PMC5009806 DOI: 10.15252/emmm.201606370] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Immunotherapeutic approaches are currently the most advanced treatments for Alzheimer's disease (AD). Antibodies against amyloid β-peptide (Aβ) bind to amyloid plaques and induce their clearance by microglia via Fc receptor-mediated phagocytosis. Dysfunctions of microglia may play a pivotal role in AD pathogenesis and could result in reduced efficacy of antibody-mediated Aβ clearance. Recently, heterozygous mutations in the triggering receptor expressed on myeloid cells 2 (TREM2), a microglial gene involved in phagocytosis, were genetically linked to late onset AD Loss of TREM2 reduces the ability of microglia to engulf Aβ. We have now investigated whether loss of TREM2 affects the efficacy of immunotherapeutic approaches. We show that anti-Aβ antibodies stimulate Aβ uptake and amyloid plaque clearance in a dose-dependent manner in the presence or absence of TREM2. However, TREM2-deficient N9 microglial cell lines, macrophages as well as primary microglia showed significantly reduced uptake of antibody-bound Aβ and as a consequence reduced clearance of amyloid plaques. Titration experiments revealed that reduced efficacy of amyloid plaque clearance by Trem2 knockout cells can be compensated by elevating the concentration of therapeutic antibodies.
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Affiliation(s)
- Xianyuan Xiang
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Georg Werner
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Bernd Bohrmann
- Roche Pharmaceutical Research and Early Development NORD Discovery & Translational Area, Roche Innovation Center Basel, Basel, Switzerland
| | - Arthur Liesz
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Fargol Mazaheri
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Anja Capell
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Regina Feederle
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany Helmholtz Center Munich, German Research Center for Environmental Health, Institute for Diabetes and Obesity Core Facility Monoclonal Antibody Development, Munich, Germany
| | - Irene Knuesel
- Roche Pharmaceutical Research and Early Development NORD Discovery & Translational Area, Roche Innovation Center Basel, Basel, Switzerland
| | - Gernot Kleinberger
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany Munich Cluster for Systems Neurology (SyNergy), Munich, Germany German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
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147
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Gispert JD, Suárez-Calvet M, Monté GC, Tucholka A, Falcon C, Rojas S, Rami L, Sánchez-Valle R, Lladó A, Kleinberger G, Haass C, Molinuevo JL. Cerebrospinal fluid sTREM2 levels are associated with gray matter volume increases and reduced diffusivity in early Alzheimer's disease. Alzheimers Dement 2016; 12:1259-1272. [PMID: 27423963 DOI: 10.1016/j.jalz.2016.06.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/28/2016] [Accepted: 06/09/2016] [Indexed: 01/12/2023]
Abstract
INTRODUCTION TREM2 is involved in the regulation of inflammatory response and phagocytosis. A soluble fragment (sTREM2) is often found abnormally increased in cerebrospinal fluid (CSF) in Alzheimer's disease (AD). METHODS One hundred fourteen participants (45 control, 19 preclinical, 27 mild cognitive impairment [MCI], and 23 AD) underwent CSF sTREM2 determination and magnetic resonance imaging (MRI). We studied the association between CSF sTREM2, gray matter volume, and water motion diffusivity and anisotropy across groups. RESULTS In MCI patients, a positive correlation between CSF sTREM2 and gray matter volume was found in the bilateral inferior and middle temporal cortices, precuneus, the supramarginal, and angular gyri, after controlling by age, sex, and p-tau. A negative correlation with mean diffusivity was detected in overlapping regions, among others. DISCUSSION In early AD, augmented CSF sTREM2 levels correspond with cerebral MRI features typical of brain swelling, supporting a role for TREM2 in the regulation of the neuroinflammatory response to early neurodegeneration.
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Affiliation(s)
- Juan Domingo Gispert
- Barcelonaβeta Brain Research Center, Pasqual Maragall Foundation, Barcelona, Spain; Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain; Pompeu Fabra University, Barcelona, Spain
| | - Marc Suárez-Calvet
- BioMedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Gemma C Monté
- Alzheimer's Disease and Other Cognitive Disorders Unit, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Alan Tucholka
- Barcelonaβeta Brain Research Center, Pasqual Maragall Foundation, Barcelona, Spain
| | - Carles Falcon
- Barcelonaβeta Brain Research Center, Pasqual Maragall Foundation, Barcelona, Spain; Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain
| | - Santiago Rojas
- Barcelonaβeta Brain Research Center, Pasqual Maragall Foundation, Barcelona, Spain; Unit of human Anatomy and Embryology, Department of Morphological Sciences, Faculty of Medicine, Autonomous University of Barcelona, Cerdanyola del Vallès, Spain
| | - Lorena Rami
- Alzheimer's Disease and Other Cognitive Disorders Unit, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Raquel Sánchez-Valle
- Alzheimer's Disease and Other Cognitive Disorders Unit, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Albert Lladó
- Alzheimer's Disease and Other Cognitive Disorders Unit, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Gernot Kleinberger
- BioMedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- BioMedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - José Luis Molinuevo
- Barcelonaβeta Brain Research Center, Pasqual Maragall Foundation, Barcelona, Spain; Alzheimer's Disease and Other Cognitive Disorders Unit, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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148
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Zufiría M, Gil-Bea FJ, Fernández-Torrón R, Poza JJ, Muñoz-Blanco JL, Rojas-García R, Riancho J, López de Munain A. ALS: A bucket of genes, environment, metabolism and unknown ingredients. Prog Neurobiol 2016; 142:104-129. [DOI: 10.1016/j.pneurobio.2016.05.004] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/11/2022]
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149
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Cerebrospinal fluid soluble TREM2 is higher in Alzheimer disease and associated with mutation status. Acta Neuropathol 2016; 131:925-33. [PMID: 26754641 DOI: 10.1007/s00401-016-1533-5] [Citation(s) in RCA: 243] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 12/31/2015] [Accepted: 01/01/2016] [Indexed: 01/30/2023]
Abstract
Low frequency coding variants in TREM2 are associated with increased Alzheimer disease (AD) risk, while loss of functions mutations in the gene lead to an autosomal recessive early-onset dementia, named Nasu-Hakola disease (NHD). TREM2 can be detected as a soluble protein in cerebrospinal fluid (CSF) and plasma, and its CSF levels are elevated in inflammatory CNS diseases. We measured soluble TREM2 (sTREM2) in the CSF of a large AD case-control dataset (n = 180) and 40 TREM2 risk variant carriers to determine whether CSF sTREM2 levels are associated with AD status or mutation status. We also performed genetic studies to identify genetic variants associated with CSF sTREM2 levels. CSF, but not plasma, sTREM2 was highly correlated with CSF total tau and phosphorylated-tau levels (r = 0.35, P < 1×10(-4); r = 0.40, P < 1×10(-4), respectively), but not with CSF Aβ42. AD cases presented higher CSF sTREM2 levels than controls (P = 0.01). Carriers of NHD-associated TREM2 variants presented significantly lower CSF sTREM2 levels, supporting the hypothesis that these mutations lead to reduced protein production/function (R136Q, D87N, Q33X or T66M; P = 1×10(-3)). In contrast, CSF sTREM2 levels were significantly higher in R47H carriers compared to non-carriers (P = 6×10(-3)), suggesting that this variant does not impact protein expression and increases AD risk through a different pathogenic mechanism than NHD variants. In GWAS analyses for CSF sTREM2 levels the most significant signal was located on the MS4A gene locus (P = 5.45 × 10(-07)) corresponding to one of the SNPs reported to be associated with AD risk in this locus. Furthermore, SNPs involved in pathways related to virus cellular entry and vesicular trafficking were overrepresented, suggesting that CSF sTREM2 levels could be an informative phenotype for AD.
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Abstract
Alzheimer's disease (AD) is a progressive, neurodegenerative disease and the most common form of dementia in elderly people. It is an emerging public health problem that poses a huge societal burden. Linkage analysis was the first milestone in unraveling the mutations in APP, PSEN1, and PSEN2 that cause early-onset AD, followed by the discovery of apolipoprotein E-ε4 allele as the only one genetic risk factor for late-onset AD. Genome-wide association studies have revolutionized genetic research and have identified over 20 genetic loci associated with late-onset AD. Recently, next-generation sequencing technologies have enabled the identification of rare disease variants, including unmasking small mutations with intermediate risk of AD in PLD3, TREM2, UNC5C, AKAP9, and ADAM10. This review provides an overview of the genetic basis of AD and the relationship between these risk genes and the neuropathologic features of AD. An understanding of genetic mechanisms underlying AD pathogenesis and the potentially implicated pathways will lead to the development of novel treatment for this devastating disease.
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Affiliation(s)
- Mohan Giri
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, People’s Republic of China
| | - Man Zhang
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, People’s Republic of China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, People’s Republic of China
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