51
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Yang J, Fu Z, Zhang X, Xiong M, Meng L, Zhang Z. TREM2 ectodomain and its soluble form in Alzheimer's disease. J Neuroinflammation 2020; 17:204. [PMID: 32635934 PMCID: PMC7341574 DOI: 10.1186/s12974-020-01878-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is a receptor mainly expressed on the surface of microglia. It mediates multiple pathophysiological processes in various diseases. Recently, TREM2 has been found to play a role in the development of Alzheimer's disease (AD). TREM2 is a transmembrane protein that is specifically expressed on microglia in the brain. It contains a long ectodomain that directly interacts with the extracellular environment to regulate microglial function. The ectodomain of TREM2 is processed by a disintegrin and metalloprotease, resulting in the release of a soluble form of TREM2 (sTREM2). Recent studies have demonstrated that sTREM2 is a bioactive molecule capable of binding ligands, activating microglia, and regulating immune responses during the AD continuum. Clinical studies revealed that sTREM2 level is elevated in cerebrospinal fluid (CSF) of AD patients, and the sTREM2 level is positively correlated with the levels of classical CSF biomarkers, namely t-tau and p-tau, indicating that it is a reliable predictor of the early stages of AD. Herein, we summarize the key results on the generation, structure, and function of sTREM2 to provide new insights into TREM2-related mechanisms underlying AD pathogenesis and to promote the development of TREM2-based therapeutic strategy.
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Affiliation(s)
- Jiaolong Yang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhihui Fu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Xingyu Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Min Xiong
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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Bera S, Camblor‐Perujo S, Calleja Barca E, Negrete‐Hurtado A, Racho J, De Bruyckere E, Wittich C, Ellrich N, Martins S, Adjaye J, Kononenko NL. AP-2 reduces amyloidogenesis by promoting BACE1 trafficking and degradation in neurons. EMBO Rep 2020; 21:e47954. [PMID: 32323475 PMCID: PMC7271323 DOI: 10.15252/embr.201947954] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 12/13/2022] Open
Abstract
Cleavage of amyloid precursor protein (APP) by BACE-1 (β-site APP cleaving enzyme 1) is the rate-limiting step in amyloid-β (Aβ) production and a neuropathological hallmark of Alzheimer's disease (AD). Despite decades of research, mechanisms of amyloidogenic APP processing remain highly controversial. Here, we show that in neurons, APP processing and Aβ production are controlled by the protein complex-2 (AP-2), an endocytic adaptor known to be required for APP endocytosis. Now, we find that AP-2 prevents amyloidogenesis by additionally functioning downstream of BACE1 endocytosis, regulating BACE1 endosomal trafficking and its delivery to lysosomes. AP-2 is decreased in iPSC-derived neurons from patients with late-onset AD, while conditional AP-2 knockout (KO) mice exhibit increased Aβ production, resulting from accumulation of BACE1 within late endosomes and autophagosomes. Deletion of BACE1 decreases amyloidogenesis and mitigates synapse loss in neurons lacking AP-2. Taken together, these data suggest a mechanism for BACE1 intracellular trafficking and degradation via an endocytosis-independent function of AP-2 and reveal a novel role for endocytic proteins in AD.
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Affiliation(s)
- Sujoy Bera
- CECAD Research CenterUniversity of CologneCologneGermany
- Present address:
Centre for Neuroscience and Regenerative MedicineFaculty of ScienceUniversity of Technology SydneySydneyNSWAustralia
| | | | | | | | - Julia Racho
- CECAD Research CenterUniversity of CologneCologneGermany
| | | | | | - Nina Ellrich
- CECAD Research CenterUniversity of CologneCologneGermany
| | - Soraia Martins
- Institute for Stem Cell Research and Regenerative MedicineMedical FacultyHeinrich Heine UniversityDüsseldorfGermany
| | - James Adjaye
- Institute for Stem Cell Research and Regenerative MedicineMedical FacultyHeinrich Heine UniversityDüsseldorfGermany
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53
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Qin Z, Gu M, Zhou J, Zhang W, Zhao N, Lü Y, Yu W. Triggering receptor expressed on myeloid cells 2 activation downregulates toll-like receptor 4 expression and ameliorates cognitive impairment in the Aβ 1-42 -induced Alzheimer's disease mouse model. Synapse 2020; 74:e22161. [PMID: 32412103 DOI: 10.1002/syn.22161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/18/2020] [Accepted: 05/04/2020] [Indexed: 01/15/2023]
Abstract
Increasing evidence suggests that changes in the triggering receptor expressed on myeloid cells 2 (TREM2) is closely correlated with the pathological development of Alzheimer's disease (AD). However, the biological function and related role of this change remain poorly understood. Higher TREM2 expression has been reported in the brain of AD patients than in normal controls. Here, levels of TREM2 gene and protein levels were observed to be higher in both cortex and hippocampus of the Aβ1-42 -induced AD mice than in those of the wild type mice. Together with in vitro experimental data, we found that the anti-inflammatory role of TREM2 was, to some extent, limited and potentially counteracted by the hyperactive toll-like receptor 4 (TLR4) in the AD mice. In this context, Interleukin 4 (IL-4), as an agonist of TREM2, was administered to the AD mice to persistently activate TREM2. Interestingly, TREM2 activation in IL-4-treated AD mice led to an elevation in lysosomes and microtubule-associated protein 1 light chain 3 (LC3) II/I expression, demonstrating that the level of microglia autophagy was increased. Increased autophagy significantly downregulated the expression levels of caspase recruitment domain-containing protein 9 (CARD9) and TLR4, potentially weakening the CARD9-TLR4 pathway and suppressing the TLR4-mediated pro-inflammatory effect in IL-4-treated AD mice. Furthermore, data acquired from Morris water maze testing indicated that IL-4 administration could ameliorate cognitive impairment in the AD mice. In conclusion, the findings from in vitro and in vivo experiments suggest that TREM2 might represent a potential drug target to treat neuroinflammation in AD.
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Affiliation(s)
- Zhangjin Qin
- Department of Human Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China.,Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Min Gu
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jian Zhou
- Department of Human Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Wenbo Zhang
- Department of Human Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China.,Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Nan Zhao
- Department of Human Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Yang Lü
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Weihua Yu
- Department of Human Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China
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54
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Yoo SM, Park J, Kim SH, Jung YK. Emerging perspectives on mitochondrial dysfunction and inflammation in Alzheimer's disease. BMB Rep 2020. [PMID: 31818363 PMCID: PMC6999830 DOI: 10.5483/bmbrep.2020.53.1.274] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Despite enduring diverse insults, mitochondria maintain normal functions through mitochondrial quality control. However, the failure of mitochondrial quality control resulting from excess damage and mechanical defects causes mitochondrial dysfunction, leading to various human diseases. Recent studies have reported that mitochondrial defects are found in Alzheimer’s disease (AD) and worsen AD symptoms. In AD pathogenesis, mitochondrial dysfunction-driven generation of reactive oxygen species (ROS) and their contribution to neuronal damage has been widely studied. In contrast, studies on mitochondrial dysfunction-associated inflammatory responses have been relatively scarce. Moreover, ROS produced upon failure of mitochondrial quality control may be linked to the inflammatory response and influence the progression of AD. Thus, this review will focus on inflammatory pathways that are associated with and initiated through defective mitochondria and will summarize recent progress on the role of mitochondria-mediated inflammation in AD. We will also discuss how reducing mitochondrial dysfunction-mediated inflammation could affect AD.
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Affiliation(s)
- Seung-Min Yoo
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Jisu Park
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Seo-Hyun Kim
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
| | - Yong-Keun Jung
- School of Biological Sciences, Seoul National University, Seoul 08826, Korea
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55
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Toomey CE, Heywood W, Benson BC, Packham G, Mills K, Lashley T. Investigation of pathology, expression and proteomic profiles in human TREM2 variant postmortem brains with and without Alzheimer's disease. Brain Pathol 2020; 30:794-810. [PMID: 32267026 PMCID: PMC8018003 DOI: 10.1111/bpa.12842] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/11/2020] [Accepted: 03/26/2020] [Indexed: 12/17/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 TREM2 was identified as a risk factor for late onset Alzheimer’s disease (AD). Here we compared TREM2 cases with a variant (TREM2+) and cases without a TREM2 variant (TREM2−), considering pathological burden, inflammatory response and altered canonical pathways and biochemical functions between the cohorts. We hypothesised that TREM2+ cases would have a loss of function, indicating an altered inflammatory profile compared to TREM2− cases. Immunohistochemistry was performed using antibodies against Aβ, tau and microglia markers in TREM2+ cases, with and without AD, which were compared to sporadic TREM2− AD, familial AD and neurologically normal control cases. Aβ and tau load were measured along with the composition of Aβ plaques, in addition to microglial load and circularity. Expression and proteomic profiles were determined from the frontal cortex of selected cases. TREM2+ control cases had no Aβ or tau deposition. No differences in the amount of Aβ or tau, or the composition of Aβ plaques were observed between TREM2+ and TREM2− SAD cases. There were no differences in microglial load observed between disease groups. However, the TREM2+ SAD cases showed more amoeboid microglia than the TREM2− SAD cases, although no differences in the spatial relationship of microglia and Aβ plaques were identified. Visualisation of the canonical pathways and biological functions showed differences between the disease groups and the normal controls, clearly showing a number of pathways upregulated in TREM2+ SAD, TREM2− SAD and FAD groups whilst, the TREM2+ controls cases showed a downregulation of the majority of the represented pathways. These findings suggest that the TREM2+ control group, although carrying the TREM2+ variant, have no pathological hallmarks of AD, have altered microglial and expression profiles compared to the TREM2+ SAD cases. This indicates that other unknown factors may initiate the onset of AD, with TREM2 influencing the microglial involvement in disease pathogenesis.
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Affiliation(s)
- Christina E Toomey
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Wendy Heywood
- Centre for Translational Omics, Great Ormond Street Institute of Child Health, UCL, London, UK
| | - Bridget C Benson
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Georgia Packham
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Kevin Mills
- Centre for Translational Omics, Great Ormond Street Institute of Child Health, UCL, London, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK.,Department of Neurodegenerative diseases, UCL Queen Square Institute of Neurology, London, UK
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56
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Mapstone M, Gross TJ, Macciardi F, Cheema AK, Petersen M, Head E, Handen BL, Klunk WE, Christian BT, Silverman W, Lott IT, Schupf N. Metabolic correlates of prevalent mild cognitive impairment and Alzheimer's disease in adults with Down syndrome. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2020; 12:e12028. [PMID: 32258359 PMCID: PMC7131985 DOI: 10.1002/dad2.12028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/14/2020] [Accepted: 02/19/2020] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Disruption of metabolic function is a recognized feature of late onset Alzheimer's disease (LOAD). We sought to determine whether similar metabolic pathways are implicated in adults with Down syndrome (DS) who have increased risk for Alzheimer's disease (AD). METHODS We examined peripheral blood from 292 participants with DS who completed baseline assessments in the Alzheimer's Biomarkers Consortium-Down Syndrome (ABC-DS) using untargeted mass spectrometry (MS). Our sample included 38 individuals who met consensus criteria for AD (DS-AD), 43 who met criteria for mild cognitive impairment (DS-MCI), and 211 who were cognitively unaffected and stable (CS). RESULTS We measured relative abundance of 8,805 features using MS and 180 putative metabolites were differentially expressed (DE) among the groups at false discovery rate-corrected q< 0.05. From the DE features, a nine-feature classifier model classified the CS and DS-AD groups with receiver operating characteristic area under the curve (ROC AUC) of 0.86 and a two-feature model classified the DS-MCI and DS-AD groups with ROC AUC of 0.88. Metabolite set enrichment analysis across the three groups suggested alterations in fatty acid and carbohydrate metabolism. DISCUSSION Our results reveal metabolic alterations in DS-AD that are similar to those seen in LOAD. The pattern of results in this cross-sectional DS cohort suggests a dynamic time course of metabolic dysregulation which evolves with clinical progression from non-demented, to MCI, to AD. Metabolomic markers may be useful for staging progression of DS-AD.
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Affiliation(s)
- Mark Mapstone
- Department of NeurologyUniversity of California‐IrvineIrvineCaliforniaUSA
| | - Thomas J Gross
- Department of NeurologyUniversity of California‐IrvineIrvineCaliforniaUSA
| | - Fabio Macciardi
- Department of Psychiatry and Human BehaviorUniversity of California‐IrvineIrvineCaliforniaUSA
| | - Amrita K Cheema
- Departments of Biochemistry and Molecular & Cellular BiologyGeorgetown University Medical CenterWashingtonDCUSA
| | - Melissa Petersen
- Institute for Translational ResearchUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Elizabeth Head
- Department of Pathology and Laboratory MedicineUniversity of California‐IrvineIrvineCaliforniaUSA
| | - Benjamin L Handen
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - William E Klunk
- Department of PsychiatryUniversity of PittsburghPittsburghPennsylvaniaUSA
- Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Bradley T Christian
- Departments of Medical Physics and PsychiatryWaisman CenterUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
| | - Wayne Silverman
- Department of PediatricsUniversity of California‐ IrvineIrvineCaliforniaUSA
| | - Ira T Lott
- Department of PediatricsUniversity of California‐ IrvineIrvineCaliforniaUSA
| | - Nicole Schupf
- Taub Institute for Research in Alzheimer's Disease and the Aging BrainColumbia UniversityNew YorkNew YorkUSA
- Department of NeurologyColumbia University and the New York Presbyterian HospitalNew YorkNew YorkUSA
- Department of EpidemiologyJoseph P. Mailman School of Public HealthColumbia UniversityNew YorkNew YorkUSA
- Gertrude H. Sergievsky CenterColumbia UniversityNew YorkNew YorkUSA
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57
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Anwar S, Rivest S. Alzheimer's disease: microglia targets and their modulation to promote amyloid phagocytosis and mitigate neuroinflammation. Expert Opin Ther Targets 2020; 24:331-344. [PMID: 32129117 DOI: 10.1080/14728222.2020.1738391] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Introduction: Despite the revolutionary progress in neurodegenerative disease research, there is no cure for Alzheimer's disease (AD). This is a chronic progressive neurodegenerative disease affecting aged people and is associated with chronic neuroinflammation and amyloid-beta (Aβ) deposition in the brain parenchyma. Microglia, the resident myeloid cells in the central nervous system, are critically involved in the pathogenesis of AD and have emerged as a potential therapeutic target for treating or preventing AD. The failure of microglia to keep up with persistent amyloid-beta development along with secretion of inflammatory cytokines is detrimental to neurons and favors Aβ accumulation.Areas covered: This review illuminates the latest research that is focused on molecules and their intracellular targets that promote microglial phagocytosis and /or its polarization to an anti-inflammatory state.Expert opinion: A robust inflammatory response of microglia is not necessary to improve their efficiency of Aβ clearance. The challenge is to master inflammatory/anti-inflammatory phenotypes depending on the stage of AD and to maintain efficient responses to remove Aβ. Therefore, promoting microglia phagocytosis without a persistent excessive inflammatory response could be a potential therapeutic strategy.
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Affiliation(s)
- Shehata Anwar
- Neuroscience Laboratory, CHU de Québec Research Center (CHUL), Department of Molecular Medicine, Faculty of Medicine, Laval University, Quebec City, QC, Canada.,Department of Pathology, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
| | - Serge Rivest
- Neuroscience Laboratory, CHU de Québec Research Center (CHUL), Department of Molecular Medicine, Faculty of Medicine, Laval University, Quebec City, QC, Canada
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58
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Bonvicini C, Scassellati C, Benussi L, Di Maria E, Maj C, Ciani M, Fostinelli S, Mega A, Bocchetta M, Lanzi G, Giacopuzzi E, Ferraboli S, Pievani M, Fedi V, Defanti CA, Giliani S, Frisoni GB, Ghidoni R, Gennarelli M. Next Generation Sequencing Analysis in Early Onset Dementia Patients. J Alzheimers Dis 2020; 67:243-256. [PMID: 30530974 PMCID: PMC6398561 DOI: 10.3233/jad-180482] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background: Early onset dementias (EOD) are rare neurodegenerative dementias that present before 65 years. Genetic factors have a substantially higher pathogenetic contribution in EOD patients than in late onset dementia. Objective: To identify known and/or novel rare variants in major candidate genes associated to EOD by high-throughput sequencing. Common-risk variants of apolipoprotein E (APOE) and prion protein (PRNP) genes were also assessed. Methods: We studied 22 EOD patients recruited in Memory Clinics, in the context of studies investigating genetic forms of dementia. Two methodological approaches were applied for the target-Next Generation Sequencing (NGS) analysis of these patients. In addition, we performed progranulin plasma dosage, C9Orf72 hexanucleotide repeat expansion analysis, and APOE genotyping. Results: We detected three rare known pathogenic mutations in the GRN and PSEN2 genes and eleven unknown-impact mutations in the GRN, VCP, MAPT, FUS, TREM2, and NOTCH3 genes. Six patients were carriers of only common risk variants (APOE and PRNP), and one did not show any risk mutation/variant. Overall, 69% (n = 9) of our early onset Alzheimer’s disease (EAOD) patients, compared with 34% (n = 13) of sporadic late onset Alzheimer’s disease (LOAD) patients and 27% (n = 73) of non-affected controls (ADNI, whole genome data), were carriers of at least two rare/common risk variants in the analyzed candidate genes panel, excluding the full penetrant mutations. Conclusion: This study suggests that EOD patients without full penetrant mutations are characterized by higher probability to carry polygenic risk alleles that patients with LOAD forms. This finding is in line with recently reported evidence, thus suggesting that the genetic risk factors identified in LOAD might modulate the risk also in EOAD.
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Affiliation(s)
- Cristian Bonvicini
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Catia Scassellati
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Luisa Benussi
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Emilio Di Maria
- Department of Health Sciences, University of Genova and Division of Medical Genetics, Galliera Hospital, Genova, Italy
| | - Carlo Maj
- Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Institute for Genomic Statistics and Bioinformatics, Bonn, Germany
| | - Miriam Ciani
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Silvia Fostinelli
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Anna Mega
- Laboratory Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Martina Bocchetta
- Laboratory Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Gaetana Lanzi
- A. Nocivelli' Institute for Molecular Medicine Spedali Civili and University of Brescia, Brescia, Italy
| | - Edoardo Giacopuzzi
- Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Sergio Ferraboli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Michela Pievani
- Laboratory Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | | | - Carlo Alberto Defanti
- Fondazione Europea Ricerca Biomedica, Centro di Eccellenza Alzheimer, Ospedale Briolini Gazzaniga, Bergamo, Italy
| | - Silvia Giliani
- A. Nocivelli' Institute for Molecular Medicine Spedali Civili and University of Brescia, Brescia, Italy
| | | | - Giovanni Battista Frisoni
- Laboratory Alzheimer's Neuroimaging and Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Laboratory of Neuroimaging of Aging (LANVIE), University Hospitals and University of Geneva, Geneva, Switzerland; Department of Internal Medicine, University Hospitals and University of Geneva, Geneva, Switzerland
| | - Roberta Ghidoni
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Massimo Gennarelli
- Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.,Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
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Singh AK, Mishra G, Maurya A, Awasthi R, Kumari K, Thakur A, Rai A, Rai GK, Sharma B, Kulkarni GT, Singh SK. Role of TREM2 in Alzheimer's Disease and its Consequences on β- Amyloid, Tau and Neurofibrillary Tangles. Curr Alzheimer Res 2020; 16:1216-1229. [DOI: 10.2174/1567205016666190903102822] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/21/2019] [Accepted: 08/21/2019] [Indexed: 11/22/2022]
Abstract
:
Alzheimer's Disease (AD) is age-related neurodegenerative disorder recognized by a steadily
gradual cognitive decline that has devastating personal and socioeconomic implications. Recently, some
genetic factors for AD have been identified which attracted wide attention of researchers in different
areas of AD biology and possible new therapeutic targets. Alternative forms of triggering receptor expressed
on myeloid cells 2 (TREM2) genes are examples of such risk factors, which contribute higher
risk for developing AD. Comprehending TREM2 function pledge to provide salient insight into how
neuroinflammation contributes to AD pathology. The dearth of microglial TREM2 shepherd to augmented
tau pathology is couple with frequent enhancement of activated neuronal stress kinases. The involvement
of TREM2 in the regulation of tau-associated innate immune response of the CNS has clearly
demonstrated through these findings. However, whether decrease level of TREM2 assists pathology of
tau through changed clearance and pathological escalation of tau or through direct contact between microglia
and neuron and any alternative possible mechanisms need to examine. This review briefly summarizes
distinct functional roles of TREM2 in AD pathology and highlights the TREM2 gene regulation.
We have also addressed the impact of TREM2 on β-amyloid plaques and tau pathology in Alzheimer’s
disease.
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Affiliation(s)
- Anurag K. Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
| | - Gaurav Mishra
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Anand Maurya
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Rajendra Awasthi
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Komal Kumari
- Department of Pharmacy, School of Chemical Sciences & Pharmacy, Central University of Rajasthan, Bandar Sindri, Kishangarh, Ajmer-305817, Rajasthan, India
| | - Abhimanyu Thakur
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong SAR, China
| | - Arati Rai
- Hygia Institute of Pharmaceutical Education & Research, Lucknow-226020, Uttar Pradesh, India
| | - Gopal Kumar Rai
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi- 221005, Uttar Pradesh, India
| | - Bhupesh Sharma
- Department of Pharmacology, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Giriraj T Kulkarni
- Department of Pharmaceutics, Amity Institute of Pharmacy, Amity University Uttar Pradesh, Sector 125, Noida - 201303, India
| | - Santosh Kumar Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
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Reich M, Paris I, Ebeling M, Dahm N, Schweitzer C, Reinhardt D, Schmucki R, Prasad M, Köchl F, Leist M, Cowley SA, Zhang JD, Patsch C, Gutbier S, Britschgi M. Alzheimer's Risk Gene TREM2 Determines Functional Properties of New Type of Human iPSC-Derived Microglia. Front Immunol 2020; 11:617860. [PMID: 33613545 PMCID: PMC7887311 DOI: 10.3389/fimmu.2020.617860] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/29/2020] [Indexed: 12/17/2022] Open
Abstract
Microglia are key in the homeostatic well-being of the brain and microglial dysfunction has been implicated in neurodegenerative disorders such as Alzheimer's disease (AD). Due to the many limitations to study microglia in situ or isolated for large scale drug discovery applications, there is a high need to develop robust and scalable human cellular models of microglia with reliable translatability to the disease. Here, we describe the generation of microglia-like cells from human induced pluripotent stem cells (iPSC) with distinct phenotypes for mechanistic studies in AD. We started out from an established differentiation protocol to generate primitive macrophage precursors mimicking the yolk sac ontogeny of microglia. Subsequently, we tested 36 differentiation conditions for the cells in monoculture where we exposed them to various combinations of media, morphogens, and extracellular matrices. The optimized protocol generated robustly ramified cells expressing key microglial markers. Bulk mRNA sequencing expression profiles revealed that compared to cells obtained in co-culture with neurons, microglia-like cells derived from a monoculture condition upregulate mRNA levels for Triggering Receptor Expressed On Myeloid Cells 2 (TREM2), which is reminiscent to the previously described disease-associated microglia. TREM2 is a risk gene for AD and an important regulator of microglia. The regulatory function of TREM2 in these cells was confirmed by comparing wild type with isogenic TREM2 knock-out iPSC microglia. The TREM2-deficient cells presented with stronger increase in free cytosolic calcium upon stimulation with ATP and ADP, as well as stronger migration towards complement C5a, compared to TREM2 expressing cells. The functional differences were associated with gene expression modulation of key regulators of microglia. In conclusion, we have established and validated a work stream to generate functional human iPSC-derived microglia-like cells by applying a directed and neuronal co-culture independent differentiation towards functional phenotypes in the context of AD. These cells can now be applied to study AD-related disease settings and to perform compound screening and testing for drug discovery.
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Affiliation(s)
- Marvin Reich
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland.,In Vitro Toxicology and Biomedicine, Department inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Konstanz, Germany
| | - Iñaki Paris
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland.,Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Leioa, Spain
| | - Martin Ebeling
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Nadine Dahm
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Christophe Schweitzer
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Dieter Reinhardt
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Roland Schmucki
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Megana Prasad
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Fabian Köchl
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department inaugurated by the Doerenkamp-Zbinden Foundation, University of Konstanz, Konstanz, Germany
| | - Sally A Cowley
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Jitao David Zhang
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Christoph Patsch
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Simon Gutbier
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Markus Britschgi
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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61
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Golde TE. Harnessing Immunoproteostasis to Treat Neurodegenerative Disorders. Neuron 2019; 101:1003-1015. [PMID: 30897353 DOI: 10.1016/j.neuron.2019.02.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/05/2019] [Accepted: 02/15/2019] [Indexed: 12/12/2022]
Abstract
Immunoproteostasis is a term used to reflect interactions between the immune system and the proteinopathies that are presumptive "triggers" of many neurodegenerative disorders. The study of immunoproteostasis is bolstered by several observations. Mutations or rare variants in genes expressed in microglial cells, known to regulate immune functions, or both can cause, or alter risk for, various neurodegenerative disorders. Additionally, genetic association studies identify numerous loci harboring genes that encode proteins of known immune function that alter risk of developing Alzheimer's disease (AD) and other neurodegenerative proteinopathies. Further, preclinical studies reveal beneficial effects and liabilities of manipulating immune pathways in various neurodegenerative disease models. Although there are concerns that manipulation of the immune system may cause more harm than good, there is considerable interest in developing immune modulatory therapies for neurodegenerative disorders. Herein, I highlight the promise and challenges of harnessing immunoproteostasis to treat neurodegenerative proteinopathies.
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Affiliation(s)
- Todd E Golde
- McKnight Brain Institute, Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience and Neurology, University of Florida, Gainesville, FL 32607, USA.
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62
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Knock-in of Mutated hTAU Causes Insulin Resistance, Inflammation and Proteostasis Disturbance in a Mouse Model of Frontotemporal Dementia. Mol Neurobiol 2019; 57:539-550. [PMID: 31396860 PMCID: PMC6968995 DOI: 10.1007/s12035-019-01722-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/26/2019] [Indexed: 12/21/2022]
Abstract
Diabetes and obesity have been implicated as risk factors for dementia. However, metabolic mechanisms and associated signalling pathways have not been investigated in detail in frontotemporal dementia. We therefore here characterised physiological, behavioural and molecular phenotypes of 3- and 8-month-old male tau knock-in (PLB2TAU) vs wild-type (PLBWT) mice. Homecage analysis suggested intact habituation but a dramatic reduction in exploratory activity in PLB2TAU mice. Deficits in motor strength were also observed. At 3 months, PLB2TAU mice displayed normal glucose handling but developed hyperglycaemia at 8 months, suggesting a progressive diabetic phenotype. Brain, liver and muscle tissue analyses confirmed tissue-specific deregulation of metabolic and homeostatic pathways. In brain, increased levels of phosphorylated tau and inflammation were detected alongside reduced ER regulatory markers, overall suggesting a downregulation in essential cellular defence pathways. We suggest that subtle neuronal expression of mutated human tau is sufficient to disturb systems metabolism and protein handling. Whether respective dysfunctions in tauopathy patients are also a consequence of tau pathology remains to be confirmed, but could offer new avenues for therapeutic interventions.
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63
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Elder GA, Ehrlich ME, Gandy S. Relationship of traumatic brain injury to chronic mental health problems and dementia in military veterans. Neurosci Lett 2019; 707:134294. [PMID: 31141716 DOI: 10.1016/j.neulet.2019.134294] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/25/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023]
Abstract
Traumatic brain injury (TBI) is an unfortunately common event in military life. The conflicts in Iraq and Afghanistan have increased public awareness of TBI in the military. Certain injury mechanisms are relatively unique to the military, the most prominent being blast exposure. Blast-related mild TBI (mTBI) has been of particular concern in the most recent veterans although controversy remains concerning separation of the postconcussion syndrome associated with mTBI from post-traumatic stress disorder. TBI is also a risk factor for the development of neurodegenerative diseases including chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD). AD, TBI, and CTE are all associated with chronic inflammation. Genome wide association studies (GWAS) have identified multiple genetic loci associated with AD that implicate inflammation and - in particular microglia - as key modulators of the AD- and TBI-related degenerative processes. At the molecular level, recent studies have identified TREM2 and TYROBP/DAP12 as components of a key molecular hub linking inflammation and microglia to the pathophysiology of AD and possibly TBI. Evidence concerning the relationship of TBI to chronic mental health problems and dementia is reviewed in the context of its relevance to military veterans.
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Affiliation(s)
- Gregory A Elder
- Neurology Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA; Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Michelle E Ehrlich
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA
| | - Sam Gandy
- Department of Neurology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, USA; Mount Sinai Alzheimer's Disease Research Center and the Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA; NFL Neurological Care Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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64
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Tao CC, Cheng KM, Ma YL, Hsu WL, Chen YC, Fuh JL, Lee WJ, Chao CC, Lee EHY. Galectin-3 promotes Aβ oligomerization and Aβ toxicity in a mouse model of Alzheimer's disease. Cell Death Differ 2019; 27:192-209. [PMID: 31127200 PMCID: PMC7206130 DOI: 10.1038/s41418-019-0348-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 04/13/2019] [Accepted: 05/02/2019] [Indexed: 12/23/2022] Open
Abstract
Amyloid-β (Aβ) oligomers largely initiate the cascade underlying the pathology of Alzheimer's disease (AD). Galectin-3 (Gal-3), which is a member of the galectin protein family, promotes inflammatory responses and enhances the homotypic aggregation of cancer cells. Here, we examined the role and action mechanism of Gal-3 in Aβ oligomerization and Aβ toxicities. Wild-type (WT) and Gal-3-knockout (KO) mice, APP/PS1;WT mice, APP/PS1;Gal-3+/- mice and brain tissues from normal subjects and AD patients were used. We found that Aβ oligomerization is reduced in Gal-3 KO mice injected with Aβ, whereas overexpression of Gal-3 enhances Aβ oligomerization in the hippocampi of Aβ-injected mice. Gal-3 expression shows an age-dependent increase that parallels endogenous Aβ oligomerization in APP/PS1 mice. Moreover, Aβ oligomerization, Iba1 expression, GFAP expression and amyloid plaque accumulation are reduced in APP/PS1;Gal-3+/- mice compared with APP/PS1;WT mice. APP/PS1;Gal-3+/- mice also show better acquisition and retention performance compared to APP/PS1;WT mice. In studying the mechanism underlying Gal-3-promoted Aβ oligomerization, we found that Gal-3 primarily co-localizes with Iba1, and that microglia-secreted Gal-3 directly interacts with Aβ. Gal-3 also interacts with triggering receptor expressed on myeloid cells-2, which then mediates the ability of Gal-3 to activate microglia for further Gal-3 expression. Immunohistochemical analyses show that the distribution of Gal-3 overlaps with that of endogenous Aβ in APP/PS1 mice and partially overlaps with that of amyloid plaque. Moreover, the expression of the Aβ-degrading enzyme, neprilysin, is increased in Gal-3 KO mice and this is associated with enhanced integrin-mediated signaling. Consistently, Gal-3 expression is also increased in the frontal lobe of AD patients, in parallel with Aβ oligomerization. Because Gal-3 expression is dramatically increased as early as 3 months of age in APP/PS1 mice and anti-Aβ oligomerization is believed to protect against Aβ toxicity, Gal-3 could be considered a novel therapeutic target in efforts to combat AD.
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Affiliation(s)
- Chih-Chieh Tao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Kuang-Min Cheng
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Institute of Neuroscience, National Cheng-chi University, Taipei, Taiwan
| | - Yun-Li Ma
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wei-Lun Hsu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yan-Chu Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Jong-Ling Fuh
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wei-Ju Lee
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Neurological Institute, Taichung Veterans General Hospital, Taichung, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Chih-Chang Chao
- Institute of Neuroscience, National Cheng-chi University, Taipei, Taiwan
| | - Eminy H Y Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan. .,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan. .,Institute of Neuroscience, National Cheng-chi University, Taipei, Taiwan.
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65
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Kaur D, Sharma V, Deshmukh R. Activation of microglia and astrocytes: a roadway to neuroinflammation and Alzheimer's disease. Inflammopharmacology 2019; 27:663-677. [PMID: 30874945 DOI: 10.1007/s10787-019-00580-x] [Citation(s) in RCA: 250] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 03/06/2019] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that is of high importance to the neuroscience world, yet the complex pathogenicity is not fully understood. Inflammation is usually observed in AD and could implicate both beneficial or detrimental effects depending on the severity of the disease. During initial AD pathology, microglia and astrocyte activation is beneficial since they are involved in amyloid-beta clearance. However, with the progression of the disease, activated microglia elicit detrimental effects by the overexpression of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) bringing forth neurodegeneration in the surrounding brain regions. This results in decline in Aβ clearance by microglia; Aβ accumulation thus increases in the brain resulting in neuroinflammation. Thus, Aβ accumulation is the effect of increased release of pro-inflammatory molecules. Reactive astrocytes acquire gain of toxic function and exhibits neurotoxic effects with loss of neurotrophic functions. Astrocyte dysfunctioning results in increased release of cytokines and inflammatory mediators, neurodegeneration, decreased glutamate uptake, loss of neuronal synapses, and ultimately cognitive deficits in AD. We discuss the role of intracellular signaling pathways in the inflammatory responses produced by astrocytes and microglial activation, including the glycogen synthase kinase-3β, nuclear factor kappa B cascade, mitogen-activated protein kinase pathways and c-Jun N-terminal kinase. In this review, we describe the role of neuroinflammation in the chronicity of AD pathogenesis and an overview of the recent research towards the development of new therapies to treat this disorder.
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Affiliation(s)
- Darshpreet Kaur
- Department of Pharmaceutical Sciences and Technology, Maharaja Ranjit Singh Punjab Technical University, Bathinda, Punjab, 151001, India
| | - Vivek Sharma
- Government College of Pharmacy, Rohru, Shimla, Himachal Pradesh, 171207, India
| | - Rahul Deshmukh
- Department of Pharmaceutical Sciences and Technology, Maharaja Ranjit Singh Punjab Technical University, Bathinda, Punjab, 151001, India.
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66
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Imbalance of Microglial TLR4/TREM2 in LPS-Treated APP/PS1 Transgenic Mice: A Potential Link Between Alzheimer's Disease and Systemic Inflammation. Neurochem Res 2019; 44:1138-1151. [PMID: 30756214 DOI: 10.1007/s11064-019-02748-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023]
Abstract
Clinically, superimposed systemic inflammation generally has significant deleterious effects on the Alzheimer's disease (AD) progression. However, the related molecular mechanisms remain poorly understood. Microglial toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells 2 (TREM2) are two key regulators of inflammation that may play an essential role in this complex pathophysiological process. In this study, intraperitoneal injection of lipopolysaccharide (LPS) into APP/PS1 transgenic AD model was used to mimic systemic inflammation in the development of AD. Initial results from the cortex showed that compared with wild-type mice, APP/PS1 mice exhibited elevated gene and protein expression levels of both TLR4 and TREM2 with different degree. Interestingly, after LPS treatment, TLR4 expression was persistently up-regulated, while TREM2 expression was significantly down-regulated in APP/PS1 mice, suggesting that the negative regulatory effect of TREM2 on inflammation might be suppressed by LPS-induced hyperactive TLR4. This imbalance of TLR4/TREM2 contributed to microglial over-activation, followed by increased neuronal apoptosis in the cortex of APP/PS1 mice; these changes did not alter the expression level of Aβ1-42. Similar alterations were observed in our in vitro experiment with β-amyloid1-42 (Aβ1-42)-treated N9 microglia. Further, Morris water maze (MWM) testing data indicated that LPS administration acutely aggravated cognitive impairment in APP/PS1 mice, suggesting that the addition of systemic inflammation can potentially accelerate the progression of AD. Collectively, we conclude that an imbalance of TLR4/TREM2 may be a potential link between AD and systemic inflammation. TREM2 can serve as a potential therapeutic target for treating systemic inflammation in AD progression.
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67
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Gratuze M, Leyns CEG, Holtzman DM. New insights into the role of TREM2 in Alzheimer's disease. Mol Neurodegener 2018; 13:66. [PMID: 30572908 PMCID: PMC6302500 DOI: 10.1186/s13024-018-0298-9] [Citation(s) in RCA: 258] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 11/28/2018] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia. The two histopathological markers of AD are amyloid plaques composed of the amyloid-β (Aβ) peptide, and neurofibrillary tangles of aggregated, abnormally hyperphosphorylated tau protein. The majority of AD cases are late-onset, after the age of 65, where a clear cause is still unknown. However, there are likely different multifactorial contributors including age, enviornment, biology and genetics which can increase risk for the disease. Genetic predisposition is considerable, with heritability estimates of 60-80%. Genetic factors such as rare variants of TREM2 (triggering receptor expressed on myeloid cells-2) strongly increase the risk of developing AD, confirming the role of microglia in AD pathogenesis. In the last 5 years, several studies have dissected the mechanisms by which TREM2, as well as its rare variants affect amyloid and tau pathologies and their consequences in both animal models and in human studies. In this review, we summarize increases in our understanding of the involvement of TREM2 and microglia in AD development that may open new therapeutic strategies targeting the immune system to influence AD pathogenesis.
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Affiliation(s)
- Maud Gratuze
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Cheryl E. G. Leyns
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - David M. Holtzman
- Department of Neurology, St. Louis, USA
- Hope Center for Neurological Disorders, St. Louis, USA
- Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110 USA
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68
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Guerreiro R, Orme T, Naj AC, Kuzma AB, Schellenberg GD, Bras J. Is APOE ε4 required for Alzheimer's disease to develop in TREM2 p.R47H variant carriers? Neuropathol Appl Neurobiol 2018; 45:187-189. [PMID: 30229991 DOI: 10.1111/nan.12517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- R Guerreiro
- UK Dementia Research Institute at UCL (UK DRI), London, UK.,Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK.,Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - T Orme
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - A C Naj
- Department of Biostatistics, Epidemiology, and Informatics/Centre for Clinical Epidemiology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Penn Neurodegeneration Genomics Centre, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - A B Kuzma
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Penn Neurodegeneration Genomics Centre, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - G D Schellenberg
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Department of Genetics, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - J Bras
- UK Dementia Research Institute at UCL (UK DRI), London, UK.,Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK.,Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
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69
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The role of TREM2 in Alzheimer's disease and other neurodegenerative disorders. Lancet Neurol 2018; 17:721-730. [PMID: 30033062 DOI: 10.1016/s1474-4422(18)30232-1] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease is a genetically complex disorder; rare variants in the triggering receptor expressed on myeloid cells 2 (TREM2) gene have been shown to as much as triple an individual's risk of developing Alzheimer's disease. TREM2 is a transmembrane receptor expressed in cells of the myeloid lineage, and its association with Alzheimer's disease supports the involvement of immune and inflammatory pathways in the cause of the disease, rather than as a consequence of the disease. TREM2 variants associated with Alzheimer's disease induce partial loss of function of the TREM2 protein and alter the behaviour of microglial cells, including their response to amyloid plaques. TREM2 variants have also been shown to cause polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy and frontotemporal dementia. Although the low frequency of TREM2 variants makes it difficult to establish robust genotype-phenotype correlations, such studies are essential to enable a comprehensive understanding of the role of TREM2 in different neurological diseases, with the ultimate goal of developing novel therapeutic approaches.
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70
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Stem Cells as Potential Targets of Polyphenols in Multiple Sclerosis and Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2018; 2018:1483791. [PMID: 30112360 PMCID: PMC6077677 DOI: 10.1155/2018/1483791] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/19/2018] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) and multiple sclerosis are major neurodegenerative diseases, which are characterized by the accumulation of abnormal pathogenic proteins due to oxidative stress, mitochondrial dysfunction, impaired autophagy, and pathogens, leading to neurodegeneration and behavioral deficits. Herein, we reviewed the utility of plant polyphenols in regulating proliferation and differentiation of stem cells for inducing brain self-repair in AD and multiple sclerosis. Firstly, we discussed the genetic, physiological, and environmental factors involved in the pathophysiology of both the disorders. Next, we reviewed various stem cell therapies available and how they have proved useful in animal models of AD and multiple sclerosis. Lastly, we discussed how polyphenols utilize the potential of stem cells, either complementing their therapeutic effects or stimulating endogenous and exogenous neurogenesis, against these diseases. We suggest that polyphenols could be a potential candidate for stem cell therapy against neurodegenerative disorders.
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71
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Navarro V, Sanchez-Mejias E, Jimenez S, Muñoz-Castro C, Sanchez-Varo R, Davila JC, Vizuete M, Gutierrez A, Vitorica J. Microglia in Alzheimer's Disease: Activated, Dysfunctional or Degenerative. Front Aging Neurosci 2018; 10:140. [PMID: 29867449 PMCID: PMC5958192 DOI: 10.3389/fnagi.2018.00140] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/25/2018] [Indexed: 12/11/2022] Open
Abstract
Microglial activation has been considered a crucial player in the pathological process of multiple human neurodegenerative diseases. In some of these pathologies, such as Amyotrophic Lateral Sclerosis or Multiple Sclerosis, the immune system and microglial cells (as part of the cerebral immunity) play a central role. In other degenerative processes, such as Alzheimer’s disease (AD), the role of microglia is far to be elucidated. In this “mini-review” article, we briefly highlight our recent data comparing the microglial response between amyloidogenic transgenic models, such as APP/PS1 and AD patients. Since the AD pathology could display regional heterogeneity, we focus our work at the hippocampal formation. In APP based models a prominent microglial response is triggered around amyloid-beta (Aβ) plaques. These strongly activated microglial cells could drive the AD pathology and, in consequence, could be implicated in the neurodegenerative process observed in models. On the contrary, the microglial response in human samples is, at least, partial or attenuated. This patent difference could simply reflect the lower and probably slower Aβ production observed in human hippocampal samples, in comparison with models, or could reflect the consequence of a chronic long-standing microglial activation. Beside this differential response, we also observed microglial degeneration in Braak V–VI individuals that, indeed, could compromise their normal role of surveying the brain environment and respond to the damage. This microglial degeneration, particularly relevant at the dentate gyrus, might be mediated by the accumulation of toxic soluble phospho-tau species. The consequences of this probably deficient immunological protection, observed in AD patients, are unknown.
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Affiliation(s)
- Victoria Navarro
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Elisabeth Sanchez-Mejias
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Instituto de Biomedicina de Malaga (IBIMA), Universidad de Málaga, Málaga, Spain
| | - Sebastian Jimenez
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Clara Muñoz-Castro
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Raquel Sanchez-Varo
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Instituto de Biomedicina de Malaga (IBIMA), Universidad de Málaga, Málaga, Spain
| | - Jose C Davila
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Instituto de Biomedicina de Malaga (IBIMA), Universidad de Málaga, Málaga, Spain
| | - Marisa Vizuete
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Antonia Gutierrez
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Instituto de Biomedicina de Malaga (IBIMA), Universidad de Málaga, Málaga, Spain
| | - Javier Vitorica
- Departamento Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain.,Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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Abstract
Microglia are a subset of tissue macrophages that constitute the major immune cell type of the central nervous system. These cells have long been known to change their morphology and functions in response to various neurological insults. Recently, a plethora of unbiased transcriptomics studies have revealed that across a broad spectrum of neurodegeneration-like disease models, microglia adopt a similar activation signature and perform similar functions. Despite these commonalities in response, the role of microglia has been described as both positive and negative in different murine disease models. In humans, genetic association studies have revealed strong connections between microglia genes and various neurodegenerative diseases, and mechanistic investigations of these mutations have added another layer of complexity. Here, we provide an overview of studies that have built a case for a common microglial response to neurodegeneration and discuss pathways that may be important to initiate and sustain this response; delineate the multifaceted functions of activated microglia spanning different diseases; and discuss insights from studying genes associated with disease in humans. We argue that strong evidence causally links activated microglia function to neurodegeneration and discuss what seems to be a conflict between mouse models and human genetics.
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Affiliation(s)
- Wilbur M Song
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, United States.
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73
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Li Q, Wang BL, Sun FR, Li JQ, Cao XP, Tan L. The role of UNC5C in Alzheimer's disease. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:178. [PMID: 29951500 DOI: 10.21037/atm.2018.04.43] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is a chronic progressive neurodegenerative disease in adults characterized by the deposition of extracellular plaques of β-amyloid protein (Aβ), intracellular neurofibrillary tangles (NFTs), synaptic loss and neuronal apoptosis. AD has a strong and complex genetic component that involving into multiple genes. With recent advances in whole-exome sequencing (WES) and whole-genome sequencing (WGS) technology, UNC5C was identified to have association with AD. Emerging studies on cell and animal models identified that aberrant UNC5C may contribute to AD by activating death-associated protein kinase 1 (DAPK1) which is a new component involved in AD pathogenesis with an extensive involvement in aberrant tau, Aβ and neuronal apoptosis/autophagy. In this review, we briefly summarize the biochemical properties, genetics, epigenetics, and the speculative role of UNC5C in AD. We hope our review would bring comprehensive understandings of AD pathogenesis and provide new therapeutic targets for AD.
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Affiliation(s)
- Quan Li
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China
| | - Bai-Ling Wang
- Department of Geriatrics, Qingdao Mental Health Center, Qingdao 266034, China
| | - Fu-Rong Sun
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China
| | - Jie-Qiong Li
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China
| | - Xi-Peng Cao
- Clinical Research Center, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao 266071, China
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74
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Zhong L, Wang Z, Wang D, Wang Z, Martens YA, Wu L, Xu Y, Wang K, Li J, Huang R, Can D, Xu H, Bu G, Chen XF. Amyloid-beta modulates microglial responses by binding to the triggering receptor expressed on myeloid cells 2 (TREM2). Mol Neurodegener 2018; 13:15. [PMID: 29587871 PMCID: PMC5870375 DOI: 10.1186/s13024-018-0247-7] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 03/20/2018] [Indexed: 12/20/2022] Open
Abstract
Background TREM2 is an innate immune receptor specifically expressed in microglia. Coding variations in TREM2 have been reported to increase the risk for Alzheimer’s disease (AD) and other neurodegenerative diseases. While multiple studies support a role for TREM2 in microglial recruitment to amyloid plaques, the chemoattractant factor modulating TREM2-dependent microglial responses has not been defined. Methods Potential binding of oligomeric amyloid-β 1–42 (oAβ1–42) to TREM2 was tested by complementary approaches including solid phase binding, surface plasmon resonance and immunoprecipitation assays. The ability of oAβ1–42 to activate TREM2 signaling pathways was examined by analyzing the phosphorylation of Syk and Akt in primary microglia as well as TREM2-mediated signaling in a reporter cell system. Lastly, the functional outcome of oAβ1–42-TREM2 interaction was tested by examining impacts on microglial migration in vitro and clustering around oAβ1–42-bearing brain areas in vivo. Results We found that oAβ1–42 bound to TREM2 with high affinity and activated TREM2-dependent signaling pathway. Neither monomeric nor scrambled Aβ bound to TREM2 supporting a specific interaction between oAβ and TREM2. The disease-associated mutations of TREM2 reduced its binding affinity to oAβ1–42. Furthermore, we identified several positively charged amino acids within residues 31–91 of TREM2 that were crucial for its interaction with oAβ1–42. Importantly, oAβ1–42 promoted microglial migration in vitro and clustering in vivo in a TREM2-dependent manner. Conclusions Our data establish a critical link between oAβ1–42, a major pathological component of AD, and TREM2, a strong genetic risk factor for AD expressed in microglia, and suggest that such interaction contributes to the pathogenic events in AD by modulating microglial responses. Electronic supplementary material The online version of this article (10.1186/s13024-018-0247-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Li Zhong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Zongqi Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Daxin Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Zhe Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Yuka A Martens
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Linbei Wu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Ying Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Kai Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Jianguo Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Ruizhi Huang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Dan Can
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.,Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China. .,Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
| | - Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China. .,Shenzhen Research Institute of Xiamen University, Shenzhen, 518063, China.
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75
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Murray CE, King A, Troakes C, Hodges A, Lashley T. APOE ε4 is also required in TREM2 R47H variant carriers for Alzheimer's disease to develop. Neuropathol Appl Neurobiol 2018; 45:183-186. [PMID: 29411406 DOI: 10.1111/nan.12474] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/23/2018] [Indexed: 01/04/2023]
Affiliation(s)
- C E Murray
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - A King
- Department of Clinical Neuropathology, Kings College Hospital, London, UK.,London Neurodegenerative Diseases Brain Bank, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK
| | - C Troakes
- London Neurodegenerative Diseases Brain Bank, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - A Hodges
- Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - T Lashley
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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76
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Pasanen P, Myllykangas L, Pöyhönen M, Kiviharju A, Siitonen M, Hardy J, Bras J, Paetau A, Tienari PJ, Guerreiro R, Verkkoniemi-Ahola A. Genetics of dementia in a Finnish cohort. Eur J Hum Genet 2018; 26:827-837. [PMID: 29476165 DOI: 10.1038/s41431-018-0117-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 12/03/2017] [Accepted: 02/01/2018] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) and frontotemporal dementia (FTD) are the two most common neurodegenerative dementias. Variants in APP, PSEN1 and PSEN2 are typically linked to early-onset AD, and several genetic risk loci are associated with late-onset AD. Inherited FTD can be caused by hexanucleotide expansions in C9orf72, or variants in GRN, MAPT or CHMP2B. Several other genes have also been linked to FTD or FTD with motor neuron disease. Here we describe a cohort of 60 Finnish families with possible inherited dementia. Our aim was to clarify the genetic background of dementia in this cohort by analysing both known dementia-associated genes (APOE, APP, C9ORF72, GRN, PSEN1 and PSEN2) and searching for rare or novel segregating variants with exome sequencing. C9orf72 repeat expansions were detected in 12 (20%) of the 60 families, including, in addition to FTD, a family with neuropathologically verified AD. Twelve families (10 with AD and 2 with FTD) with representative samples from affected and unaffected subjects and without C9orf72 expansions were selected for whole-exome sequencing. Exome sequencing did not reveal any variants that could be regarded unequivocally causative, but revealed potentially damaging variants in UNC13C and MARCH4.
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Affiliation(s)
- Petra Pasanen
- Department of Medical Biochemistry and Genetics, Institute of Biomedicine, University of Turku, Turku, Finland. .,Tyks Genetics and Saske, Department of Medical Genetics, Turku University Hospital, Turku, Finland.
| | - Liisa Myllykangas
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Minna Pöyhönen
- Department of Clinical Genetics, Helsinki University Central Hospital, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
| | - Anna Kiviharju
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Maija Siitonen
- Department of Medical Biochemistry and Genetics, Institute of Biomedicine, University of Turku, Turku, Finland
| | - John Hardy
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Jose Bras
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute at UCL, London, UK.,Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Anders Paetau
- Department of Pathology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Pentti J Tienari
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.,Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Rita Guerreiro
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK.,UK Dementia Research Institute at UCL, London, UK.,Department of Medical Sciences and Institute of Biomedicine - iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Auli Verkkoniemi-Ahola
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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77
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Hopperton KE, Mohammad D, Trépanier MO, Giuliano V, Bazinet RP. Markers of microglia in post-mortem brain samples from patients with Alzheimer's disease: a systematic review. Mol Psychiatry 2018; 23:177-198. [PMID: 29230021 PMCID: PMC5794890 DOI: 10.1038/mp.2017.246] [Citation(s) in RCA: 297] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/15/2017] [Accepted: 09/14/2017] [Indexed: 02/07/2023]
Abstract
Neuroinflammation is proposed as one of the mechanisms by which Alzheimer's disease pathology, including amyloid-β plaques, leads to neuronal death and dysfunction. Increases in the expression of markers of microglia, the main neuroinmmune cell, are widely reported in brains from patients with Alzheimer's disease, but the literature has not yet been systematically reviewed to determine whether this is a consistent pathological feature. A systematic search was conducted in Medline, Embase and PsychINFO for articles published up to 23 February 2017. Papers were included if they quantitatively compared microglia markers in post-mortem brain samples from patients with Alzheimer's disease and aged controls without neurological disease. A total of 113 relevant articles were identified. Consistent increases in markers related to activation, such as major histocompatibility complex II (36/43 studies) and cluster of differentiation 68 (17/21 studies), were identified relative to nonneurological aged controls, whereas other common markers that stain both resting and activated microglia, such as ionized calcium-binding adaptor molecule 1 (10/20 studies) and cluster of differentiation 11b (2/5 studies), were not consistently elevated. Studies of ionized calcium-binding adaptor molecule 1 that used cell counts almost uniformly identified no difference relative to control, indicating that increases in activation occurred without an expansion of the total number of microglia. White matter and cerebellum appeared to be more resistant to these increases than other brain regions. Nine studies were identified that included high pathology controls, patients who remained free of dementia despite Alzheimer's disease pathology. The majority (5/9) of these studies reported higher levels of microglial markers in Alzheimer's disease relative to controls, suggesting that these increases are not solely a consequence of Alzheimer's disease pathology. These results show that increased markers of microglia are a consistent feature of Alzheimer's disease, though this seems to be driven primarily by increases in activation-associated markers, as opposed to markers of all microglia.
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Affiliation(s)
- K E Hopperton
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - D Mohammad
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - M O Trépanier
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - V Giuliano
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - R P Bazinet
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada,Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, FitzGerald Building, 150 College Street, Room 306, Toronto, ON M5S 3E2, Canada. E-mail:
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78
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Taipa R, Sousa AL, Melo Pires M, Sousa N. Does the Interplay Between Aging and Neuroinflammation Modulate Alzheimer's Disease Clinical Phenotypes? A Clinico-Pathological Perspective. J Alzheimers Dis 2018; 53:403-17. [PMID: 27176075 DOI: 10.3233/jad-160121] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disorder and is the most common cause of dementia worldwide. Cumulative data suggests that neuroinflammation plays a prominent and early role in AD, and there is compelling data from different research groups of age-associated dysregulation of the neuroimmune system. From the clinical point of view, despite clinical resemblance and neuropathological findings, there are important differences between the group of patients with sporadic early-onset (<65 years old) and late-onset AD (>65 years old). Thus, it seems important to understand the age-dependent relationship between neuroinflammation and the underlying biology of AD in order to identify potential explanations for clinical heterogeneity, interpret biomarkers, and promote the best treatment to different clinical AD phenotypes. The study of the delicate balance between pro-inflammatory or anti-inflammatory sides of immune players in the different ages of onset of AD would be important to understand treatment efficacy in clinical trials and eventually, not only direct treatment to early disease stages, but also the possibility of establishing different treatment approaches depending on the age of the patient. In this review, we would like to summarize what is currently known about the interplay between "normal" age associated inflammatory changes and AD pathological mechanisms, and also the potential differences between early-onset and late-onset AD taking into account the age-related neuroimmune background at disease onset.
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Affiliation(s)
- Ricardo Taipa
- Neuropathology Unit, Department of Neuroscience, Hospital Santo António - Centro Hospitalar do Porto, Porto, Portugal.,Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3B's Associate Lab, PT Government Associated Lab, Braga/Guimarães, Portugal
| | - Ana Luísa Sousa
- Department of Neurology, Hospital Santo António - Centro Hospitalar do Porto, Porto, Portugal
| | - Manuel Melo Pires
- Neuropathology Unit, Department of Neuroscience, Hospital Santo António - Centro Hospitalar do Porto, Porto, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3B's Associate Lab, PT Government Associated Lab, Braga/Guimarães, Portugal
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79
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Song WM, Joshita S, Zhou Y, Ulland TK, Gilfillan S, Colonna M. Humanized TREM2 mice reveal microglia-intrinsic and -extrinsic effects of R47H polymorphism. J Exp Med 2018; 215:745-760. [PMID: 29321225 PMCID: PMC5839761 DOI: 10.1084/jem.20171529] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/07/2017] [Accepted: 12/18/2017] [Indexed: 12/20/2022] Open
Abstract
The R47H variant of the microglia gene TREM2 has been linked to a significantly higher risk of Alzheimer’s disease. In this study, Song et al. generate human TREM2-expressing mice and demonstrate that R47H leads to a decreased microglia number and activation as well as a decreased presence of soluble TREM2 on neurons and plaques in a mouse model of Alzheimer’s disease. Alzheimer’s disease (AD) is a neurodegenerative disease that causes late-onset dementia. The R47H variant of the microglial receptor TREM2 triples AD risk in genome-wide association studies. In mouse AD models, TREM2-deficient microglia fail to proliferate and cluster around the amyloid-β plaques characteristic of AD. In vitro, the common variant (CV) of TREM2 binds anionic lipids, whereas R47H mutation impairs binding. However, in vivo, the identity of TREM2 ligands and effect of the R47H variant remain unknown. We generated transgenic mice expressing human CV or R47H TREM2 and lacking endogenous TREM2 in the 5XFAD AD model. Only the CV transgene restored amyloid-β–induced microgliosis and microglial activation, indicating that R47H impairs TREM2 function in vivo. Remarkably, soluble TREM2 was found on neurons and plaques in CV- but not R47H-expressing 5XFAD brains, although in vitro CV and R47H were shed similarly via Adam17 proteolytic activity. These results demonstrate that TREM2 interacts with neurons and plaques duing amyloid-β accumulation and R47H impairs this interaction.
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Affiliation(s)
- Wilbur M Song
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Satoru Joshita
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO.,Department of Medicine, Division of Gastroenterology and Hepatology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yingyue Zhou
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Tyler K Ulland
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Susan Gilfillan
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO
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80
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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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81
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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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82
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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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83
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Wang X, Zhou X, Li G, Zhang Y, Wu Y, Song W. Modifications and Trafficking of APP in the Pathogenesis of Alzheimer's Disease. Front Mol Neurosci 2017; 10:294. [PMID: 28966576 PMCID: PMC5605621 DOI: 10.3389/fnmol.2017.00294] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD), the most common neurodegenerative disorder, is the leading cause of dementia. Neuritic plaque, one of the major characteristics of AD neuropathology, mainly consists of amyloid β (Aβ) protein. Aβ is derived from amyloid precursor protein (APP) by sequential cleavages of β- and γ-secretase. Although APP upregulation can promote AD pathogenesis by facilitating Aβ production, growing evidence indicates that aberrant post-translational modifications and trafficking of APP play a pivotal role in AD pathogenesis by dysregulating APP processing and Aβ generation. In this report, we reviewed the current knowledge of APP modifications and trafficking as well as their role in APP processing. More importantly, we discussed the effect of aberrant APP modifications and trafficking on Aβ generation and the underlying mechanisms, which may provide novel strategies for drug development in AD.
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Affiliation(s)
- Xin Wang
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China
| | - Xuan Zhou
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China
| | - Gongying Li
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China.,Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical UniversityJining, China
| | - Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
| | - Yili Wu
- Department of Psychiatry, Jining Medical UniversityJining, China.,Shandong Key Laboratory of Behavioral Medicine, Jining Medical UniversityJining, China.,Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical UniversityJining, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British ColumbiaVancouver, BC, Canada
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84
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Yuan P, Condello C, Keene CD, Wang Y, Bird TD, Paul SM, Luo W, Colonna M, Baddeley D, Grutzendler J. TREM2 Haplodeficiency in Mice and Humans Impairs the Microglia Barrier Function Leading to Decreased Amyloid Compaction and Severe Axonal Dystrophy. Neuron 2017; 90:724-39. [PMID: 27196974 DOI: 10.1016/j.neuron.2016.05.003] [Citation(s) in RCA: 418] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 02/21/2016] [Accepted: 04/17/2016] [Indexed: 01/20/2023]
Abstract
Haplodeficiency of the microglia gene TREM2 increases risk for late-onset Alzheimer's disease (AD) but the mechanisms remain uncertain. To investigate this, we used high-resolution confocal and super-resolution (STORM) microscopy in AD-like mice and human AD tissue. We found that microglia processes, rich in TREM2, tightly surround early amyloid fibrils and plaques promoting their compaction and insulation. In Trem2- or DAP12-haplodeficient mice and in humans with R47H TREM2 mutations, microglia had a markedly reduced ability to envelop amyloid deposits. This led to an increase in less compact plaques with longer and branched amyloid fibrils resulting in greater surface exposure to adjacent neurites. This was associated with more severe neuritic tau hyperphosphorylation and axonal dystrophy around amyloid deposits. Thus, TREM2 deficiency may disrupt the formation of a neuroprotective microglia barrier that regulates amyloid compaction and insulation. Pharmacological modulation of this barrier could be a novel therapeutic strategy for AD.
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Affiliation(s)
- Peng Yuan
- Department of Neurology, Yale University, New Haven, CT 06511, USA; Department of Neuroscience, Yale University, New Haven, CT 06511, USA
| | - Carlo Condello
- Department of Neurology, Yale University, New Haven, CT 06511, USA
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA 98195, USA
| | - Yaming Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas D Bird
- Department of Neurology, University of Washington, Seattle, WA 98195, USA
| | - Steven M Paul
- The Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Wenjie Luo
- The Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David Baddeley
- Department of Cell Biology, Yale University, New Haven, CT 06511, USA; Nanobiology Institute, Yale University, West Haven, CT 06515, USA
| | - Jaime Grutzendler
- Department of Neurology, Yale University, New Haven, CT 06511, USA; Department of Neuroscience, Yale University, New Haven, CT 06511, USA.
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85
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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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86
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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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87
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Condello C, Stöehr J. Aβ propagation and strains: Implications for the phenotypic diversity in Alzheimer's disease. Neurobiol Dis 2017; 109:191-200. [PMID: 28359847 DOI: 10.1016/j.nbd.2017.03.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/09/2017] [Accepted: 03/26/2017] [Indexed: 12/13/2022] Open
Abstract
The progressive nature of Alzheimer's disease (AD) is thought to occur, at least in part, by the self-replication and spreading of Aβ and Tau aggregates through a prion mechanism. Evidence now exists that structural variants of Aβ prions can propagate their distinct conformations through template-directed folding of naïve Aβ peptides. This notion implicates that the first self-propagating Aβ assembly to emerge in the brain dictates the conformation, anatomical spread and pace of subsequently formed deposits. It is hypothesized that a prion mechanism defines the molecular basis underlying the diverse clinicopathologic phenotypes observed across the spectrum of AD patients. Thus, distinct AD strains might require further sub-classification based on biochemical and structural characterization of aggregated Aβ. Here, we review the evidence for distinct, self-propagating Aβ strains, and discuss potential cellular mechanisms that might contribute to their manifestation. From this perspective, we also explore the implications of Aβ strains for current FDA-approved medical imaging probes and therapies for amyloid. Ultimately, the discovery of new molecular tools to differentiate Aβ strains and dissect the heterogeneity of AD may lead to the development of more informative diagnostics and strain-specific therapeutics.
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Affiliation(s)
- Carlo Condello
- Institute for Neurodegenerative Diseases, Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, United States
| | - Jan Stöehr
- Institute for Neurodegenerative Diseases, Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, United States.
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88
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Yin J, Zhao F, Chojnacki JE, Fulp J, Klein WL, Zhang S, Zhu X. NLRP3 Inflammasome Inhibitor Ameliorates Amyloid Pathology in a Mouse Model of Alzheimer's Disease. Mol Neurobiol 2017; 55:1977-1987. [PMID: 28255908 DOI: 10.1007/s12035-017-0467-9] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/20/2017] [Indexed: 12/25/2022]
Abstract
The activation of the NLRP3 inflammasome signaling pathway plays an important role in the neuroinflammation in Alzheimer's disease (AD). In this study, we investigated the effects of JC-124, a rationally designed NLRP3 inflammasome inhibitor, on AD-related deficits in CRND8 APP transgenic mice (TgCRND8). We first demonstrated increased formation and activation of NLRP3 inflammasome in TgCRND8 mice compared to non-transgenic littermate controls, which was inhibited by the treatment with JC-124. Importantly, JC-124 treatment led to decreased levels of Aβ deposition and decreased levels of soluble and insoluble Aβ1-42 in the brain of CRND8 mice which was accompanied by reduced β-cleavage of APP, reduced activation of microglia but enhanced astrocytosis. Oxidative stress was decreased and synaptophysin was increased in the CRND8 mice after JC-124 treatment, demonstrating a neuroprotective effect. Overall, these data demonstrated beneficial effects of JC-124 as a specific NLRP3 inflammasome inhibitor in AD mouse model and supported the further development of NLRP3 inflammasome inhibitors as a viable option for AD therapeutics.
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Affiliation(s)
- Jun Yin
- Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.,Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Fanpeng Zhao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Jeremy E Chojnacki
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Jacob Fulp
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - William L Klein
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Shijun Zhang
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, 23298, USA.
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.
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89
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Zhong L, Chen XF, Wang T, Wang Z, Liao C, Wang Z, Huang R, Wang D, Li X, Wu L, Jia L, Zheng H, Painter M, Atagi Y, Liu CC, Zhang YW, Fryer JD, Xu H, Bu G. Soluble TREM2 induces inflammatory responses and enhances microglial survival. J Exp Med 2017; 214:597-607. [PMID: 28209725 PMCID: PMC5339672 DOI: 10.1084/jem.20160844] [Citation(s) in RCA: 220] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 10/25/2016] [Accepted: 01/24/2017] [Indexed: 12/31/2022] Open
Abstract
Zhong et al. describe two novel roles for soluble TREM2 (sTREM2) in regulation of proinflammatory responses and prevention of cellular apoptosis in microglia. Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor expressed in microglia in the brain. A soluble form of TREM2 (sTREM2) derived from proteolytic cleavage of the cell surface receptor is increased in the preclinical stages of AD and positively correlates with the amounts of total and phosphorylated tau in the cerebrospinal fluid. However, the physiological and pathological functions of sTREM2 remain unknown. Here, we show that sTREM2 promotes microglial survival in a PI3K/Akt-dependent manner and stimulates the production of inflammatory cytokines depending on NF-κB. Variants of sTREM2 carrying AD risk-associated mutations were less potent in both suppressing apoptosis and triggering inflammatory responses. Importantly, sTREM2 delivered to the hippocampi of both wild-type and Trem2-knockout mice elevated the expression of inflammatory cytokines and induced morphological changes of microglia. Collectively, these data indicate that sTREM2 triggers microglial activation inducing inflammatory responses and promoting survival. This study has implications for the pathogenesis of AD and provides insights into targeting sTREM2 pathway for AD therapy.
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Affiliation(s)
- Li Zhong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China .,Shenzhen Research Institute of Xiamen University, Shenzhen 518063, China
| | - Tingting Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Zhe Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Chunyan Liao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Zongqi Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Ruizhi Huang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Daxin Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Xinxiu Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Linbei Wu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Lin Jia
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - Meghan Painter
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Yuka Atagi
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224.,Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL 32224
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China.,Neuroscience and Aging Research Center, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361102, China .,Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224.,Neurobiology of Disease Graduate Program, Mayo Clinic, Jacksonville, FL 32224
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90
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Nicolas G, Charbonnier C, Campion D. From Common to Rare Variants: The Genetic Component of Alzheimer Disease. Hum Hered 2016; 81:129-141. [PMID: 28002825 DOI: 10.1159/000452256] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022] Open
Abstract
Alzheimer disease (AD) is a remarkable example of genetic heterogeneity. Extremely rare variants in the APP, PSEN1, or PSEN2 genes, or duplications of the APP gene cause autosomal dominant forms, generally with complete penetrance by the age of 65 years. Nonautosomal dominant forms are considered as a complex disorder with a high genetic component, whatever the age of onset. Although genetically heterogeneous, AD is defined by the same neuropathological criteria in all configurations. According to the amyloid cascade hypothesis, the Aβ peptide, which aggregates in AD brains, is a key player. APP, PSEN1, or PSEN2 gene mutations increase the production of more aggregation-prone forms of the Aβ peptide, triggering the pathological process. Several risk factors identified in association studies hit genes involved in Aβ production/secretion, aggregation, clearance, or toxicity. Among them, the APOE ε4 allele is a rare example of a common allele with a large effect size, the ORs ranging from 4 to 11-14 for heterozygous and homozygous carriers, respectively. In addition, genome-wide association studies have identified more than two dozen loci with a weak but significant association, the OR of the at-risk allele ranging from 1.08 to 1.30. Recently, the use of massive parallel sequencing has enabled the analysis of rare variants in a genome-wide manner. Two rare variants have been nominally associated with AD risk or protection (TREM2 p.R47H, MAF approximately 0.002, OR approximately 4 and APP p.A673T, MAF approximately 0.0005, OR approximately 0.2). Association analyses at the gene level identified rare loss-of-function and missense, predicted damaging, variants (MAF <0.01) in the SORL1 and ABCA7 genes associated with a moderate relative risk (OR approximately 5 and approximately 2.8, respectively). Although the latter analyses revealed association signals with moderately rare variants by collapsing them, the power to detect genes hit by extremely rare variants is still limited. An alternative approach is to consider the de novo paradigm, stating that de novo variants may contribute to AD genetics in sporadic patients. Here, we critically review AD genetics reports with a special focus on rare variants.
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Affiliation(s)
- Gaël Nicolas
- CNR-MAJ, Rouen University Hospital, Rouen, France
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91
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Han J, Wang M, Ren M, Lou H. Contributions of triggering-receptor-expressed-on-myeloid-cells-2 to neurological diseases. Int J Neurosci 2016; 127:368-375. [PMID: 27871212 DOI: 10.1080/00207454.2016.1264072] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Jie Han
- Department of Pharmacology, School of Medicine, Shandong University, Jinan 250012, China
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute affiliated to Shandong University, Jinan 250012, China
| | - Miaomiao Wang
- Department of Hematology, Qilu Hospital, Shandong University, Jinan 250012, China
| | - Manru Ren
- Department of Pharmacology, School of Medicine, Shandong University, Jinan 250012, China
| | - Haiyan Lou
- Department of Pharmacology, School of Medicine, Shandong University, Jinan 250012, China
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92
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Soluble phospho-tau from Alzheimer's disease hippocampus drives microglial degeneration. Acta Neuropathol 2016; 132:897-916. [PMID: 27743026 PMCID: PMC5106501 DOI: 10.1007/s00401-016-1630-5] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/05/2016] [Accepted: 10/05/2016] [Indexed: 01/22/2023]
Abstract
The role of microglial cells in the development and progression of Alzheimer's disease (AD) has not been elucidated. Here, we demonstrated the existence of a weak microglial response in human AD hippocampus which is in contrast to the massive microglial activation observed in APP-based models. Most importantly, microglial cells displayed a prominent degenerative profile (dentate gyrus > CA3 > CA1 > parahippocampal gyrus), including fragmented and dystrophic processes with spheroids, a reduced numerical density, and a significant decrease in the area of surveillance ("microglial domain"). Consequently, there was a substantial decline in the area covered by microglia which may compromise immune protection and, therefore, neuronal survival. In vitro experiments demonstrated that soluble fractions (extracellular/cytosolic) from AD hippocampi were toxic for microglial cells. This toxicity was abolished by AT8 and/or AT100 immunodepletion, validating that soluble phospho-tau was the toxic agent. These results were reproduced using soluble fractions from phospho-tau-positive Thy-tau22 hippocampi. Cultured microglial cells were not viable following phagocytosis of SH-SY5Y cells expressing soluble intracellular phospho-tau. Because the phagocytic capacity of microglial cells is highly induced by apoptotic signals in the affected neurons, we postulate that accumulation of intraneuronal soluble phospho-tau might trigger microglial degeneration in the AD hippocampus. This microglial vulnerability in AD pathology provides new insights into the immunological mechanisms underlying the disease progression and highlights the need to improve or develop new animal models, as the current models do not mimic the microglial pathology observed in the hippocampus of AD patients.
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93
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Muffat J, Li Y, Jaenisch R. CNS disease models with human pluripotent stem cells in the CRISPR age. Curr Opin Cell Biol 2016; 43:96-103. [PMID: 27768957 DOI: 10.1016/j.ceb.2016.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/19/2016] [Accepted: 10/02/2016] [Indexed: 12/31/2022]
Abstract
In vitro differentiation of human pluripotent stem cells provides a systematic platform to investigate the physiological development and function of the human nervous system, as well as the etiology and consequence when these processes go awry. Recent development in three-dimensional (3D) organotypic culture systems allows modeling of the complex structure formation of the human CNS, and the intricate interactions between various resident neuronal and glial cell types. Combined with an ever-expanding genome editing and regulation toolkit such as CRISPR/Cas9, it is now a possibility to study human neurological disease in the relevant molecular, cellular and anatomical context. In this article, we review recent progress in 3D neural culture and the implications for disease modeling.
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Affiliation(s)
- Julien Muffat
- Whitehead Institute for Biomedical Research, 9Cambridge Center, Cambridge, MA 02142, United States
| | - Yun Li
- Whitehead Institute for Biomedical Research, 9Cambridge Center, Cambridge, MA 02142, United States
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, 9Cambridge Center, Cambridge, MA 02142, United States.
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94
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Tosto G, Reitz C. Genomics of Alzheimer's disease: Value of high-throughput genomic technologies to dissect its etiology. Mol Cell Probes 2016; 30:397-403. [PMID: 27618776 DOI: 10.1016/j.mcp.2016.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/08/2016] [Accepted: 09/08/2016] [Indexed: 12/31/2022]
Abstract
Late-onset Alzheimer's disease (AD), the most common neurodegenerative disorder in western countries, is clinically defined by progressive worsening in cognitive functions along with function and behavioral impairment. This ultimately results in complete incapacity and death. AD is a clinically and pathologically heterogeneous disease, and this is reflected by the numerous genetic findings that point to several diverse molecular mechanisms and pathways. Linkage, genome-wide association and next-generation sequencing studies have led to the identification of more than 20 novel susceptibility loci for AD. While these observations have significantly increased the knowledge of pathogenic mechanisms and potential therapeutic targets, a large part of the genetic component underlying AD is still unexplained. This review will summarize and discuss the major genetic findings and their potential impact on AD diagnosis and prediction of prognosis.
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Affiliation(s)
- Giuseppe Tosto
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA; The Gertrude H. Sergievsky Center, Columbia University, New York, NY, USA; The Department of Neurology, Columbia University, New York, NY, USA
| | - Christiane Reitz
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA; The Gertrude H. Sergievsky Center, Columbia University, New York, NY, USA; The Department of Neurology, Columbia University, New York, NY, USA; The Dept. of Epidemiology, Columbia University, New York, NY, USA.
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95
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Wilkins HM, Koppel SJ, Weidling IW, Roy N, Ryan LN, Stanford JA, Swerdlow RH. Extracellular Mitochondria and Mitochondrial Components Act as Damage-Associated Molecular Pattern Molecules in the Mouse Brain. J Neuroimmune Pharmacol 2016; 11:622-628. [PMID: 27562848 DOI: 10.1007/s11481-016-9704-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 08/17/2016] [Indexed: 11/26/2022]
Abstract
Mitochondria and mitochondrial debris are found in the brain's extracellular space, and extracellular mitochondrial components can act as damage associated molecular pattern (DAMP) molecules. To characterize the effects of potential mitochondrial DAMP molecules on neuroinflammation, we injected either isolated mitochondria or mitochondrial DNA (mtDNA) into hippocampi of C57BL/6 mice and seven days later measured markers of inflammation. Brains injected with whole mitochondria showed increased Tnfα and decreased Trem2 mRNA, increased GFAP protein, and increased NFκB phosphorylation. Some of these effects were also observed in brains injected with mtDNA (decreased Trem2 mRNA, increased GFAP protein, and increased NFκB phosphorylation), and mtDNA injection also caused several unique changes including increased CSF1R protein and AKT phosphorylation. To further establish the potential relevance of this response to Alzheimer's disease (AD), a brain disorder characterized by neurodegeneration, mitochondrial dysfunction, and neuroinflammation we also measured App mRNA, APP protein, and Aβ1-42 levels. We found mitochondria (but not mtDNA) injections increased these parameters. Our data show that in the mouse brain extracellular mitochondria and its components can induce neuroinflammation, extracellular mtDNA or mtDNA-associated proteins can contribute to this effect, and mitochondria derived-DAMP molecules can influence AD-associated biomarkers.
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Affiliation(s)
- Heather M Wilkins
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
| | - Scott J Koppel
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
| | - Ian W Weidling
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Nairita Roy
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Lauren N Ryan
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
| | - John A Stanford
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA.
- University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA.
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA.
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, USA.
- University of Kansas School of Medicine, MS 2012, Landon Center on Aging, 3901 Rainbow Blvd, Kansas City, KS, 66160, USA.
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96
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Cuyvers E, Sleegers K. Genetic variations underlying Alzheimer's disease: evidence from genome-wide association studies and beyond. Lancet Neurol 2016; 15:857-868. [DOI: 10.1016/s1474-4422(16)00127-7] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 12/20/2022]
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97
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Genetic Candidate Variants in Two Multigenerational Families with Childhood Apraxia of Speech. PLoS One 2016; 11:e0153864. [PMID: 27120335 PMCID: PMC4847873 DOI: 10.1371/journal.pone.0153864] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/05/2016] [Indexed: 12/31/2022] Open
Abstract
Childhood apraxia of speech (CAS) is a severe and socially debilitating form of speech sound disorder with suspected genetic involvement, but the genetic etiology is not yet well understood. Very few known or putative causal genes have been identified to date, e.g., FOXP2 and BCL11A. Building a knowledge base of the genetic etiology of CAS will make it possible to identify infants at genetic risk and motivate the development of effective very early intervention programs. We investigated the genetic etiology of CAS in two large multigenerational families with familial CAS. Complementary genomic methods included Markov chain Monte Carlo linkage analysis, copy-number analysis, identity-by-descent sharing, and exome sequencing with variant filtering. No overlaps in regions with positive evidence of linkage between the two families were found. In one family, linkage analysis detected two chromosomal regions of interest, 5p15.1-p14.1, and 17p13.1-q11.1, inherited separately from the two founders. Single-point linkage analysis of selected variants identified CDH18 as a primary gene of interest and additionally, MYO10, NIPBL, GLP2R, NCOR1, FLCN, SMCR8, NEK8, and ANKRD12, possibly with additive effects. Linkage analysis in the second family detected five regions with LOD scores approaching the highest values possible in the family. A gene of interest was C4orf21 (ZGRF1) on 4q25-q28.2. Evidence for previously described causal copy-number variations and validated or suspected genes was not found. Results are consistent with a heterogeneous CAS etiology, as is expected in many neurogenic disorders. Future studies will investigate genome variants in these and other families with CAS.
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98
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Abstract
Alzheimer's disease (AD), the most common cause of dementia in the elderly, is a complex neurodegenerative disease marked by the appearance of amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles. Alzheimer's disease has a strong genetic component, and recent advances in genome technology have unearthed novel variants in several genes, which could provide insight into the pathogenic mechanisms that contribute to AD. Particularly interesting are variants in the microglial-expressed receptor TREM2 which are associated with a 2-4-fold increased risk of developing AD. Since the discovery of a link between TREM2 and AD, multiple studies have emerged testing whether partial or complete loss of TREM2 function contributed to Aβ deposition or Aβ-associated microgliosis. Although some confounding conflicting data have emerged from these studies regarding the role of TREM2 in regulating Aβ deposition within the hippocampus, the most consistent and striking observation is a strong decrease in microgliosis surrounding Aβ plaques in TREM2 haploinsufficient and TREM2 deficient mice. Interestingly, a similar impairment in microgliosis has been reported in mouse models of prion disease, stroke, and multiple sclerosis, suggesting a critical role for TREM2 in supporting microgliosis in response to pathology in the central nervous system. In this Review, we summarize recent reports on the role of TREM2 in AD pathology and hypothesized mechanisms by which TREM2 function could influence AD-induced microgliosis.
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Affiliation(s)
- Jason D. Ulrich
- Department of
Neurology, Knight Alzheimer’s
Disease Research Center, and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - David M. Holtzman
- Department of
Neurology, Knight Alzheimer’s
Disease Research Center, and Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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99
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Celarain N, Sánchez-Ruiz de Gordoa J, Zelaya MV, Roldán M, Larumbe R, Pulido L, Echavarri C, Mendioroz M. TREM2 upregulation correlates with 5-hydroxymethycytosine enrichment in Alzheimer's disease hippocampus. Clin Epigenetics 2016; 8:37. [PMID: 27051467 PMCID: PMC4820985 DOI: 10.1186/s13148-016-0202-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 03/22/2016] [Indexed: 01/09/2023] Open
Abstract
Background Recent genome-wide association studies revealed TREM2 rs75932628-T variant to be associated with Alzheimer’s disease (AD) and other neurodegenerative diseases. However, the role that TREM2 plays in sporadic AD is largely unknown. Our aim was to assess messenger RNA (mRNA) expression levels and DNA methylation profiling of TREM2 in human hippocampus in AD brain. We measured TREM2 mRNA levels in the hippocampus in a cohort of neuropathologically confirmed controls and pure AD cases showing no other protein deposits than β-amyloid and phosphorylated tau. We also examined DNA methylation levels in the TREM2 transcription start site (TSS)-associated region by bisulfite cloning sequencing and further extended the study by measuring 5-hydroxymethycytosine (5hmC) enrichment at different regions of TREM2 by 5hmC DNA immunoprecipitation combined with real-time qPCR. Results A 3.4-fold increase in TREM2 mRNA levels was observed in the hippocampus of AD cases compared to controls (p = 1.1E-05). Interestingly, TREM2 methylation was higher in AD cases compared to controls (76.2 % ± 15.5 versus 57.9 % ± 17.1; p = 0.0016). Moreover, TREM2 mRNA levels in the AD hippocampus correlated with enrichment in 5hmC at the TREM2 gene body (r = 0.771; p = 0.005). Conclusions TREM2 mRNA levels are increased in the human hippocampus in AD cases compared to controls. DNA methylation, and particularly 5hmC, may be involved in regulating TREM2 mRNA expression in the AD brain. Further studies are guaranteed to investigate in depth the role of 5hmC in AD and other neurodegenerative disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13148-016-0202-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Naiara Celarain
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain
| | - Javier Sánchez-Ruiz de Gordoa
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain ; Department of Neurology, Complejo Hospitalario de Navarra, Pamplona, Navarra 31008 Spain ; Present address: Clínica San Miguel, Pamplona, Navarra 31006 Spain
| | - María Victoria Zelaya
- Department of Pathology, Complejo Hospitalario de Navarra, Pamplona, Navarra 31008 Spain
| | - Miren Roldán
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain
| | - Rosa Larumbe
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain ; Department of Neurology, Complejo Hospitalario de Navarra, Pamplona, Navarra 31008 Spain
| | - Laura Pulido
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain ; Department of Neurology, Complejo Hospitalario de Navarra, Pamplona, Navarra 31008 Spain ; Present address: Clínica San Miguel, Pamplona, Navarra 31006 Spain
| | - Carmen Echavarri
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain ; Hospital Psicogeriátrico Josefina Arregui, Alsasua, Navarra 31800 Spain
| | - Maite Mendioroz
- Neuroepigenetics Laboratory, Navarrabiomed-Navarra Institute for Health Research (IdiSNA), c/ Irunlarrea, Pamplona, Navarra 31008 Spain ; Department of Neurology, Complejo Hospitalario de Navarra, Pamplona, Navarra 31008 Spain
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100
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Regulation of microglial survival and proliferation in health and diseases. Semin Immunol 2016; 27:410-5. [PMID: 27033414 DOI: 10.1016/j.smim.2016.03.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 03/16/2016] [Indexed: 11/23/2022]
Abstract
Microglia play an important role in the development and maintenance of the central nervous system (CNS) under homeostatic conditions as well as during neurodegenerative diseases. Recent observations in human genomics and advances in genetic mouse models have provided insights into signaling pathways that control development, survival, proliferation and function of microglia. Alteration of these pathways contributes to the pathogenesis of CNS diseases. Here we review the current literature regarding the roles of these microglial pathways in both the normal and diseased brain and discuss areas that require further investigation.
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