401
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Takatori S, Wang W, Iguchi A, Tomita T. Genetic Risk Factors for Alzheimer Disease: Emerging Roles of Microglia in Disease Pathomechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1118:83-116. [PMID: 30747419 DOI: 10.1007/978-3-030-05542-4_5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The accumulation of aggregated amyloid β (Aβ) peptides in the brain is deeply involved in Alzheimer disease (AD) pathogenesis. Mutations in APP and presenilins play major roles in Aβ pathology in rare autosomal-dominant forms of AD, whereas pathomechanisms of sporadic AD, accounting for the majority of cases, remain unknown. In this chapter, we review current knowledge on genetic risk factors of AD, clarified by recent advances in genome analysis technology. Interestingly, TREM2 and many genes associated with disease risk are predominantly expressed in microglia, suggesting that these risk factors are involved in pathogenicity through common mechanisms involving microglia. Therefore, we focus on factors closely associated with microglia and discuss their possible roles in pathomechanisms of AD. Furthermore, we review current views on the pathological roles of microglia and emphasize the importance of microglial changes in response to Aβ deposition and mechanisms underlying the phenotypic changes. Importantly, functional outcomes of microglial activation can be both protective and deleterious to neurons. We further describe the involvement of microglia in tau pathology and the activation of other glial cells. Through these topics, we shed light on microglia as a promising target for drug development for AD and other neurological disorders.
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Affiliation(s)
- Sho Takatori
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Wenbo Wang
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Akihiro Iguchi
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.
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402
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The Role of APOE and TREM2 in Alzheimer's Disease-Current Understanding and Perspectives. Int J Mol Sci 2018; 20:ijms20010081. [PMID: 30587772 PMCID: PMC6337314 DOI: 10.3390/ijms20010081] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia worldwide. The extracellular deposits of Amyloid beta (Aβ) in the brain-called amyloid plaques, and neurofibrillary tangles-intracellular tau aggregates, are morphological hallmarks of the disease. The risk for AD is a complicated interplay between aging, genetic risk factors, and environmental influences. One of the Apolipoprotein E (APOE) alleles-APOEε4, is the major genetic risk factor for late-onset AD (LOAD). APOE is the primary cholesterol carrier in the brain, and plays an essential role in lipid trafficking, cholesterol homeostasis, and synaptic stability. Recent genome-wide association studies (GWAS) have identified other candidate LOAD risk loci, as well. One of those is the triggering receptor expressed on myeloid cells 2 (TREM2), which, in the brain, is expressed primarily by microglia. While the function of TREM2 is not fully understood, it promotes microglia survival, proliferation, and phagocytosis, making it important for cell viability and normal immune functions in the brain. Emerging evidence from protein binding assays suggests that APOE binds to TREM2 and APOE-containing lipoproteins in the brain as well as periphery, and are putative ligands for TREM2, thus raising the possibility of an APOE-TREM2 interaction modulating different aspects of AD pathology, potentially in an isoform-specific manner. This review is focusing on the interplay between APOE isoforms and TREM2 in association with AD pathology.
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403
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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: 280] [Impact Index Per Article: 46.7] [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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404
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Marttinen M, Takalo M, Natunen T, Wittrahm R, Gabbouj S, Kemppainen S, Leinonen V, Tanila H, Haapasalo A, Hiltunen M. Molecular Mechanisms of Synaptotoxicity and Neuroinflammation in Alzheimer's Disease. Front Neurosci 2018; 12:963. [PMID: 30618585 PMCID: PMC6301995 DOI: 10.3389/fnins.2018.00963] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/03/2018] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder, which is clinically associated with a global cognitive decline and progressive loss of memory and reasoning. According to the prevailing amyloid cascade hypothesis of AD, increased soluble amyloid-β (Aβ) oligomer levels impair the synaptic functions and augment calcium dyshomeostasis, neuroinflammation, oxidative stress as well as the formation of neurofibrillary tangles at specific brain regions. Emerging new findings related to synaptic dysfunction and initial steps of neuroinflammation in AD have been able to delineate the underlying molecular mechanisms, thus reinforcing the development of new treatment strategies and biomarkers for AD beyond the conventional Aβ- and tau-targeted approaches. Particularly, the identification and further characterization of disease-associated microglia and their RNA signatures, AD-associated novel risk genes, neurotoxic astrocytes, and in the involvement of complement-dependent pathway in synaptic pruning and loss in AD have set the outstanding basis for further preclinical and clinical studies. Here, we discuss the recent development and the key findings related to the novel molecular mechanisms and targets underlying the synaptotoxicity and neuroinflammation in AD.
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Affiliation(s)
- Mikael Marttinen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Mari Takalo
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Teemu Natunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Rebekka Wittrahm
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Sami Gabbouj
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Susanna Kemppainen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Ville Leinonen
- Institute of Clinical Medicine – Neurosurgery, University of Eastern Finland, Kuopio, Finland
- Department of Neurosurgery, Kuopio University Hospital, Kuopio, Finland
- Unit of Clinical Neuroscience, Neurosurgery, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Heikki Tanila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
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405
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Sfera A, Gradini R, Cummings M, Diaz E, Price AI, Osorio C. Rusty Microglia: Trainers of Innate Immunity in Alzheimer's Disease. Front Neurol 2018; 9:1062. [PMID: 30564191 PMCID: PMC6288235 DOI: 10.3389/fneur.2018.01062] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/21/2018] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease, the most common form of dementia, is marked by progressive cognitive and functional impairment believed to reflect synaptic and neuronal loss. Recent preclinical data suggests that lipopolysaccharide (LPS)-activated microglia may contribute to the elimination of viable neurons and synapses by promoting a neurotoxic astrocytic phenotype, defined as A1. The innate immune cells, including microglia and astrocytes, can either facilitate or inhibit neuroinflammation in response to peripherally applied inflammatory stimuli, such as LPS. Depending on previous antigen encounters, these cells can assume activated (trained) or silenced (tolerized) phenotypes, augmenting or lowering inflammation. Iron, reactive oxygen species (ROS), and LPS, the cell wall component of gram-negative bacteria, are microglial activators, but only the latter can trigger immune tolerization. In Alzheimer's disease, tolerization may be impaired as elevated LPS levels, reported in this condition, fail to lower neuroinflammation. Iron is closely linked to immunity as it plays a key role in immune cells proliferation and maturation, but it is also indispensable to pathogens and malignancies which compete for its capture. Danger signals, including LPS, induce intracellular iron sequestration in innate immune cells to withhold it from pathogens. However, excess cytosolic iron increases the risk of inflammasomes' activation, microglial training and neuroinflammation. Moreover, it was suggested that free iron can awaken the dormant central nervous system (CNS) LPS-shedding microbes, engendering prolonged neuroinflammation that may override immune tolerization, triggering autoimmunity. In this review, we focus on iron-related innate immune pathology in Alzheimer's disease and discuss potential immunotherapeutic agents for microglial de-escalation along with possible delivery vehicles for these compounds.
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Affiliation(s)
- Adonis Sfera
- Psychiatry, Loma Linda University, Loma Linda, CA, United States.,Patton State Hospital, San Bernardino, CA, United States
| | - Roberto Gradini
- Department of Pathology, La Sapienza University of Rome, Rome, Italy
| | | | - Eddie Diaz
- Patton State Hospital, San Bernardino, CA, United States
| | - Amy I Price
- Evidence Based Medicine, University of Oxford, Oxford, United Kingdom
| | - Carolina Osorio
- Psychiatry, Loma Linda University, Loma Linda, CA, United States
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406
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Artemisinin B Improves Learning and Memory Impairment in AD Dementia Mice by Suppressing Neuroinflammation. Neuroscience 2018; 395:1-12. [DOI: 10.1016/j.neuroscience.2018.10.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/30/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022]
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407
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Fields JA, Spencer B, Swinton M, Qvale EM, Marquine MJ, Alexeeva A, Gough S, Soontornniyomkij B, Valera E, Masliah E, Achim CL, Desplats P. Alterations in brain TREM2 and Amyloid-β levels are associated with neurocognitive impairment in HIV-infected persons on antiretroviral therapy. J Neurochem 2018; 147:784-802. [PMID: 30152135 PMCID: PMC6310632 DOI: 10.1111/jnc.14582] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 12/27/2022]
Abstract
Neuroinflammation is a common pathological correlate of HIV-associated neurocognitive disorders (HAND) in individuals on antiretroviral therapy (ART). Triggering receptor expressed on myeloid cells 2 (TREM2) regulates neuroinflammation, clears extracellular Amyloid (A)-β, surveys for damaged neurons, and orchestrates microglial differentiation. TREM2 has not been studied in HIV+ brain tissues. In this retrospective study, we investigated TREM2 expression levels and localization to microglia, Aβ protein levels, and tumor necrosis factor (TNF)-α transcript levels in the frontal cortices of 52 HIV+ decedents. All donors had been on ART; 14 were cognitively normal (CN), 17 had an asymptomatic neurocognitive impairment (ANI), and 21 had a minor neurocognitive disorder (MND). Total TREM2 protein levels were increased in the soluble and decreased in the membrane-enriched fractions of MND brain tissues compared to CN; however, brains from MND Hispanics showed the most robust alterations in TREM2 as well as significantly increased TNF-α mRNA and Aβ levels when compared to CN Hispanics. Significant alterations in the expression of total TREM2 protein and transcripts for TNF-α were not observed in non-Hispanics, despite higher levels of Aβ in the non-Hispanic CN group compared to the non-Hispanic MND groups. These findings show that decreased and increased TREM2 in membrane-bound fractions and in soluble-enriched fractions, respectively, is associated with increased Aβ and neuroinflammation in this cohort of HIV+ brains, particularly those identifying as Hispanics. These findings suggest a role for TREM2 in the brain of HIV+ individuals may deserve more investigation as a biomarker for HAND and as a possible therapeutic target. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Jerel Adam Fields
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Brian Spencer
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Mary Swinton
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Emma Martine Qvale
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - María J. Marquine
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Arina Alexeeva
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Sarah Gough
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Benchawanna Soontornniyomkij
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Elvira Valera
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Eliezer Masliah
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Cristian L. Achim
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
| | - Paula Desplats
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, United States of America
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408
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Nnah IC, Wessling-Resnick M. Brain Iron Homeostasis: A Focus on Microglial Iron. Pharmaceuticals (Basel) 2018; 11:ph11040129. [PMID: 30477086 PMCID: PMC6316365 DOI: 10.3390/ph11040129] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/14/2022] Open
Abstract
Iron is an essential trace element required for important brain functions including oxidative metabolism, synaptic plasticity, myelination, and the synthesis of neurotransmitters. Disruptions in brain iron homeostasis underlie many neurodegenerative diseases. Increasing evidence suggests that accumulation of brain iron and chronic neuroinflammation, characterized by microglia activation and secretion of proinflammatory cytokines, are hallmarks of neurodegenerative disorders including Alzheimer’ s disease. While substantial efforts have led to an increased understanding of iron metabolism and the role of microglial cells in neuroinflammation, important questions still remain unanswered. Whether or not increased brain iron augments the inflammatory responses of microglial cells, including the molecular cues that guide such responses, is still unclear. How these brain macrophages accumulate, store, and utilize intracellular iron to carry out their various functions under normal and disease conditions is incompletely understood. Here, we describe the known and emerging mechanisms involved in microglial cell iron transport and metabolism as well as inflammatory responses in the brain, with a focus on AD.
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Affiliation(s)
- Israel C Nnah
- Department of Genetics and Complex Diseases, Harvard TH Chan School of Public Health, Boston, MA 02115, USA.
| | - Marianne Wessling-Resnick
- Department of Genetics and Complex Diseases, Harvard TH Chan School of Public Health, Boston, MA 02115, USA.
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409
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Zheng H, Cheng B, Li Y, Li X, Chen X, Zhang YW. TREM2 in Alzheimer's Disease: Microglial Survival and Energy Metabolism. Front Aging Neurosci 2018; 10:395. [PMID: 30532704 PMCID: PMC6265312 DOI: 10.3389/fnagi.2018.00395] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/13/2018] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD) is the leading cause of age-related dementia among the elderly population. Recent genetic studies have identified rare variants of the gene encoding the triggering receptor expressed on myeloid cells-2 (TREM2) as significant genetic risk factors in late-onset AD (LOAD). TREM2 is specifically expressed in brain microglia and modulates microglial functions in response to key AD pathologies such as amyloid-β (Aβ) plaques and tau tangles. In this review article, we discuss recent research progress in our understanding on the role of TREM2 in microglia and its relevance to AD pathologies. In addition, we discuss evidence describing new TREM2 ligands and the role of TREM2 signaling in microglial survival and energy metabolism. A comprehensive understanding of TREM2 function in the pathogenesis of AD offers a unique opportunity to explore the potential of this microglial receptor as an alternative target in AD therapy.
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Affiliation(s)
- Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Baoying Cheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Xin Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
| | - Xiaofen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, China
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410
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Zhang X, Fu Z, Meng L, He M, Zhang Z. The Early Events That Initiate β-Amyloid Aggregation in Alzheimer's Disease. Front Aging Neurosci 2018; 10:359. [PMID: 30542277 PMCID: PMC6277872 DOI: 10.3389/fnagi.2018.00359] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 10/22/2018] [Indexed: 12/18/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the development of amyloid plaques and neurofibrillary tangles (NFTs) consisting of aggregated β-amyloid (Aβ) and tau, respectively. The amyloid hypothesis has been the predominant framework for research in AD for over two decades. According to this hypothesis, the accumulation of Aβ in the brain is the primary factor initiating the pathogenesis of AD. However, it remains elusive what factors initiate Aβ aggregation. Studies demonstrate that AD has multiple causes, including genetic and environmental factors. Furthermore, genetic factors, many age-related events and pathological conditions such as diabetes, traumatic brain injury (TBI) and aberrant microbiota also affect the aggregation of Aβ. Here we provide an overview of the age-related early events and other pathological processes that precede Aβ aggregation.
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Affiliation(s)
- Xingyu Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhihui Fu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Mingyang He
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
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411
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Wang Z, Chen Y, Li X, Sultana P, Yin M, Wang Z. Amyloid-β 1-42 dynamically regulates the migration of neural stem/progenitor cells via MAPK-ERK pathway. Chem Biol Interact 2018; 298:96-103. [PMID: 30399361 DOI: 10.1016/j.cbi.2018.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 09/15/2018] [Accepted: 11/02/2018] [Indexed: 01/06/2023]
Abstract
Neural stem/progenitor cell (NSPC) based therapy represents an attractive treatment for Alzheimer's disease (AD), the most common neurodegenerative disorder with no effective treatment to date. This can be achieved by stimulating endogenous NSPCs and/or administrating exogenously produced NSPCs. Successful repair requires the migration of NSPCs to the loci where neuronal loss occurs, differentiation and integration into neural networks. However, the progressive loss of neurons in the brain of AD patients suggests that the repair by endogenous NSPCs in the setting of AD may be defective. The production and deposition of amyloid-β1-42 (Aβ1-42) peptides is thought to be a central event in the pathogenesis of AD. Here we report that Aβ1-42 peptides inhibit the migration of in vitro cultured NSPCs by disturbing the ERK-MAPK signal pathway. We found that the migratory capacity of NSPCs was compromised upon treatment with oligomeric Aβ1-42; the inhibitory effect occurred in a dose-dependent manner. Our previous studies have shown that Aβ1-42 triggers the expression of GRK2 by unknown mechanism. Herein we found that the Aβ1-42 evoked upregulation of GRK2 expression was attenuated upon treatment with the ERK inhibitor SCH772984 at 2.5 μM, but not with inhibitors for p38 or JNK. We detected a dose-dependent increase in levels of phosphorylated ERK1/2 after incubation of cells with oligomeric Aβ1-42 peptides for 3 days. We observed that an increase in the phosphorylation of p38 and JNK coincided with reduced phosphorylation of ERK1/2 upon treatment with Aβ1-42 for 6 and/or 9 days. We hypothesize that the divergence of the activation of the MAPK family of pathways may contribute to the inhibition of NSPCs migration after the long-term incubation with Aβ1-42. Pretreatment with 1 μM MEK inhibitor U0126 reversed the effects of Aβ1-42 on GRK2 expression of and NSPC migration. Together, our results suggest that Aβ1-42 oligomers compromise the migratory capacity of NSPCs through the MEK-ERK pathway.
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Affiliation(s)
- Zhu Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yantian Chen
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xueyi Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114 the 16th Street, Charlestown, MA, 02129, USA
| | - Pinky Sultana
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ming Yin
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Zejian Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
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412
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Allen M, Wang X, Serie DJ, Strickland SL, Burgess JD, Koga S, Younkin CS, Nguyen TT, Malphrus KG, Lincoln SJ, Alamprese M, Zhu K, Chang R, Carrasquillo MM, Kouri N, Murray ME, Reddy JS, Funk C, Price ND, Golde TE, Younkin SG, Asmann YW, Crook JE, Dickson DW, Ertekin-Taner N. Divergent brain gene expression patterns associate with distinct cell-specific tau neuropathology traits in progressive supranuclear palsy. Acta Neuropathol 2018; 136:709-727. [PMID: 30136084 PMCID: PMC6208732 DOI: 10.1007/s00401-018-1900-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 07/26/2018] [Accepted: 08/15/2018] [Indexed: 12/25/2022]
Abstract
Progressive supranuclear palsy (PSP) is a neurodegenerative parkinsonian disorder characterized by tau pathology in neurons and glial cells. Transcriptional regulation has been implicated as a potential mechanism in conferring disease risk and neuropathology for some PSP genetic risk variants. However, the role of transcriptional changes as potential drivers of distinct cell-specific tau lesions has not been explored. In this study, we integrated brain gene expression measurements, quantitative neuropathology traits and genome-wide genotypes from 268 autopsy-confirmed PSP patients to identify transcriptional associations with unique cell-specific tau pathologies. We provide individual transcript and transcriptional network associations for quantitative oligodendroglial (coiled bodies = CB), neuronal (neurofibrillary tangles = NFT), astrocytic (tufted astrocytes = TA) tau pathology, and tau threads and genomic annotations of these findings. We identified divergent patterns of transcriptional associations for the distinct tau lesions, with the neuronal and astrocytic neuropathologies being the most different. We determined that NFT are positively associated with a brain co-expression network enriched for synaptic and PSP candidate risk genes, whereas TA are positively associated with a microglial gene-enriched immune network. In contrast, TA is negatively associated with synaptic and NFT with immune system transcripts. Our findings have implications for the diverse molecular mechanisms that underlie cell-specific vulnerability and disease risk in PSP.
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Affiliation(s)
- Mariet Allen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Xue Wang
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Daniel J Serie
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, 32224, USA
| | | | - Jeremy D Burgess
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Shunsuke Koga
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Curtis S Younkin
- Division of Information Technology, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Thuy T Nguyen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | | | - Sarah J Lincoln
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | | | - Kuixi Zhu
- The Center for Innovation in Brain Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Rui Chang
- The Center for Innovation in Brain Sciences, University of Arizona, Tucson, AZ, 85721, USA
- Department of Neurology, University of Arizona, Tucson, AZ, 85721, USA
| | | | - Naomi Kouri
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Melissa E Murray
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Joseph S Reddy
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Cory Funk
- Institute for Systems Biology, 401 Terry Avenue N, Seattle, WA, 98109, USA
| | - Nathan D Price
- Institute for Systems Biology, 401 Terry Avenue N, Seattle, WA, 98109, USA
| | - Todd E Golde
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA
| | - Steven G Younkin
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Yan W Asmann
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Julia E Crook
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA
| | - Nilüfer Ertekin-Taner
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
- Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Birdsall 3, Jacksonville, FL, 32224, USA.
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413
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Alasmari F, Alshammari MA, Alasmari AF, Alanazi WA, Alhazzani K. Neuroinflammatory Cytokines Induce Amyloid Beta Neurotoxicity through Modulating Amyloid Precursor Protein Levels/Metabolism. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3087475. [PMID: 30498753 PMCID: PMC6222241 DOI: 10.1155/2018/3087475] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/19/2018] [Accepted: 10/11/2018] [Indexed: 01/06/2023]
Abstract
Neuroinflammation has been observed in association with neurodegenerative diseases including Alzheimer's disease (AD). In particular, a positive correlation has been documented between neuroinflammatory cytokine release and the progression of the AD, which suggests these cytokines are involved in AD pathophysiology. A histological hallmark of the AD is the presence of beta-amyloid (Aβ) plaques and tau neurofibrillary tangles. Beta-amyloid is generated by the sequential cleavage of beta (β) and gamma (γ) sites in the amyloid precursor protein (APP) by β- and γ-secretase enzymes and its accumulation can result from either a decreased Aβ clearance or increased metabolism of APP. Previous studies reported that neuroinflammatory cytokines reduce the efflux transport of Aβ, leading to elevated Aβ concentrations in the brain. However, less is known about the effects of neuroinflammatory mediators on APP expression and metabolism. In this article, we review the modulatory role of neuroinflammatory cytokines on APP expression and metabolism, including their effects on β- and γ-secretase enzymes.
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Affiliation(s)
- Fawaz Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Musaad A. Alshammari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah F. Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Wael A. Alanazi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Khalid Alhazzani
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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414
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415
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Hickman S, Izzy S, Sen P, Morsett L, El Khoury J. Microglia in neurodegeneration. Nat Neurosci 2018; 21:1359-1369. [PMID: 30258234 DOI: 10.1038/s41593-018-0242-x] [Citation(s) in RCA: 965] [Impact Index Per Article: 160.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 08/06/2018] [Indexed: 12/13/2022]
Abstract
The neuroimmune system is involved in development, normal functioning, aging, and injury of the central nervous system. Microglia, first described a century ago, are the main neuroimmune cells and have three essential functions: a sentinel function involved in constant sensing of changes in their environment, a housekeeping function that promotes neuronal well-being and normal operation, and a defense function necessary for responding to such changes and providing neuroprotection. Microglia use a defined armamentarium of genes to perform these tasks. In response to specific stimuli, or with neuroinflammation, microglia also have the capacity to damage and kill neurons. Injury to neurons in Alzheimer's, Parkinson's, Huntington's, and prion diseases, as well as in amyotrophic lateral sclerosis, frontotemporal dementia, and chronic traumatic encephalopathy, results from disruption of the sentinel or housekeeping functions and dysregulation of the defense function and neuroinflammation. Pathways associated with such injury include several sensing and housekeeping pathways, such as the Trem2, Cx3cr1 and progranulin pathways, which act as immune checkpoints to keep the microglial inflammatory response under control, and the scavenger receptor pathways, which promote clearance of injurious stimuli. Peripheral interference from systemic inflammation or the gut microbiome can also alter progression of such injury. Initiation or exacerbation of neurodegeneration results from an imbalance between these microglial functions; correcting such imbalance may be a potential mode for therapy.
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Affiliation(s)
- Suzanne Hickman
- Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
| | - Saef Izzy
- Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
| | - Pritha Sen
- Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
| | - Liza Morsett
- Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA
| | - Joseph El Khoury
- Center for Immunology & Inflammatory Diseases, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA.
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416
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Newcombe EA, Camats-Perna J, Silva ML, Valmas N, Huat TJ, Medeiros R. Inflammation: the link between comorbidities, genetics, and Alzheimer's disease. J Neuroinflammation 2018; 15:276. [PMID: 30249283 PMCID: PMC6154824 DOI: 10.1186/s12974-018-1313-3] [Citation(s) in RCA: 333] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/11/2018] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder, most cases of which lack a clear causative event. This has made the disease difficult to characterize and, thus, diagnose. Although some cases are genetically linked, there are many diseases and lifestyle factors that can lead to an increased risk of developing AD, including traumatic brain injury, diabetes, hypertension, obesity, and other metabolic syndromes, in addition to aging. Identifying common factors and trends between these conditions could enhance our understanding of AD and lead to the development of more effective treatments. Although the immune system is one of the body’s key defense mechanisms, chronic inflammation has been increasingly linked with several age-related diseases. Moreover, it is now well accepted that chronic inflammation has an important role in the onset and progression of AD. In this review, the different inflammatory signals associated with AD and its risk factors will be outlined to demonstrate how chronic inflammation may be influencing individual susceptibility to AD. Our goal is to bring attention to potential shared signals presented by the immune system during different conditions that could lead to the development of successful treatments.
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Affiliation(s)
- Estella A Newcombe
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.
| | - Judith Camats-Perna
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia
| | - Mallone L Silva
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia
| | - Nicholas Valmas
- Queensland Brain Institute, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Tee Jong Huat
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.,Centre for Stem Cell Ageing and Regenerative Engineering, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - Rodrigo Medeiros
- Neurula Laboratory, Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Building 79, Brisbane, 4072, QLD, Australia.
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417
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Song WM, Colonna M. The identity and function of microglia in neurodegeneration. Nat Immunol 2018; 19:1048-1058. [DOI: 10.1038/s41590-018-0212-1] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/21/2018] [Indexed: 12/11/2022]
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418
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Saito T, Saido TC. Neuroinflammation in mouse models of Alzheimer's disease. ACTA ACUST UNITED AC 2018; 9:211-218. [PMID: 30546389 PMCID: PMC6282739 DOI: 10.1111/cen3.12475] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 08/19/2018] [Indexed: 12/16/2022]
Abstract
Alzheimer's disease (AD) is the most common type of neurocognitive disorder. Although both amyloid β peptide deposition and neurofibrillary tangle formation in the AD brain have been established as pathological hallmarks of the disease, many other factors contribute in a complex manner to the pathogenesis of AD before clinical symptoms of the disease become apparent. Longitudinal pathophysiological processes cause patients' brains to exist in a state of chronic neuroinflammation, with glial cells acting as key regulators of the neuroinflammatory state. However, the detailed molecular and cellular mechanisms of glial function underlying AD pathogenesis remain elusive. Furthermore, recent studies have shown that peripheral inflammatory conditions affect glial cells in the brain through a process of neuroimmune communication. Such disease complexities make it difficult for the pathogenesis of AD to be understood, and impede the development of effective therapeutic strategies to combat the disease. Relevant AD animal models are thus likely to serve as a key resource to overcome many of these issues. Furthermore, as the pathogenesis of AD might be linked to conditions both within the brain as well as peripherally, it might become necessary for AD to be studied as a whole-body disorder. The present review aimed to summarize insights regarding current AD research, and share perspectives for understanding glial function in the context of the pathogenesis of AD.
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Affiliation(s)
- Takashi Saito
- RIKEN Center for Brain Science Laboratory for Proteolytic Neuroscience Wako Japan.,Department of Neuroscience and Pathobiology Research Institute of Environmental Medicine Nagoya University Wako Japan
| | - Takaomi C Saido
- RIKEN Center for Brain Science Laboratory for Proteolytic Neuroscience Wako Japan
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419
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Xiang X, Piers TM, Wefers B, Zhu K, Mallach A, Brunner B, Kleinberger G, Song W, Colonna M, Herms J, Wurst W, Pocock JM, Haass C. The Trem2 R47H Alzheimer's risk variant impairs splicing and reduces Trem2 mRNA and protein in mice but not in humans. Mol Neurodegener 2018; 13:49. [PMID: 30185230 PMCID: PMC6126019 DOI: 10.1186/s13024-018-0280-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 08/21/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The R47H variant of the Triggering Receptor Expressed on Myeloid cells 2 (TREM2) significantly increases the risk for late onset Alzheimer's disease. Mouse models accurately reproducing phenotypes observed in Alzheimer' disease patients carrying the R47H coding variant are required to understand the TREM2 related dysfunctions responsible for the enhanced risk for late onset Alzheimer's disease. METHODS A CRISPR/Cas9-assisted gene targeting strategy was used to generate Trem2 R47H knock-in mice. Trem2 mRNA and protein levels as well as Trem2 splicing patterns were assessed in these mice, in iPSC-derived human microglia-like cells, and in human brains from Alzheimer's patients carrying the TREM2 R47H risk factor. RESULTS Two independent Trem2 R47H knock-in mouse models show reduced Trem2 mRNA and protein production. In both mouse models Trem2 haploinsufficiency was due to atypical splicing of mouse Trem2 R47H, which introduced a premature stop codon. Cellular splicing assays using minigene constructs demonstrate that the R47H variant induced abnormal splicing only occurs in mice but not in humans. TREM2 mRNA levels and splicing patterns were both normal in iPSC-derived human microglia-like cells and patient brains with the TREM2 R47H variant. CONCLUSIONS The Trem2 R47H variant activates a cryptic splice site that generates miss-spliced transcripts leading to Trem2 haploinsufficiency only in mice but not in humans. Since Trem2 R47H related phenotypes are mouse specific and do not occur in humans, humanized TREM2 R47H knock-in mice should be generated to study the cellular consequences caused by the human TREM2 R47H coding variant. Currently described phenotypes of Trem2 R47H knock-in mice can therefore not be translated to humans.
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Affiliation(s)
- Xianyuan Xiang
- Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.,Graduate School of Systemic Neuroscience, Ludwig- Maximilians- University Munich, Munich, Germany
| | - Thomas M Piers
- Department of Neuroinflammation, Cell Signalling Lab, University College London Institute of Neurology, WC1N 1PJ, London, UK
| | - Benedikt Wefers
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Kaichuan Zhu
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Anna Mallach
- Department of Neuroinflammation, Cell Signalling Lab, University College London Institute of Neurology, WC1N 1PJ, London, UK
| | - Bettina Brunner
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Gernot Kleinberger
- Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Wilbur Song
- Department of Immunology and Pathology, Washington University in St. Louis, St. Louis, MO, USA
| | - Marco Colonna
- Department of Immunology and Pathology, Washington University in St. Louis, St. Louis, MO, USA
| | - Jochen Herms
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Wolfgang Wurst
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Technische Universität München-Weihenstephan, 85764, Neuherberg/Munich, Germany
| | - Jennifer M Pocock
- Department of Neuroinflammation, Cell Signalling Lab, University College London Institute of Neurology, WC1N 1PJ, London, UK
| | - Christian Haass
- Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany. .,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany. .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
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420
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Alosco ML, Tripodis Y, Fritts NG, Heslegrave A, Baugh CM, Conneely S, Mariani M, Martin BM, Frank S, Mez J, Stein TD, Cantu RC, McKee AC, Shaw LM, Trojanowski JQ, Blennow K, Zetterberg H, Stern RA. Cerebrospinal fluid tau, Aβ, and sTREM2 in Former National Football League Players: Modeling the relationship between repetitive head impacts, microglial activation, and neurodegeneration. Alzheimers Dement 2018; 14:1159-1170. [PMID: 30049650 PMCID: PMC6131058 DOI: 10.1016/j.jalz.2018.05.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/20/2018] [Accepted: 05/15/2018] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Cerebrospinal fluid (CSF) protein analysis may facilitate detection and elucidate mechanisms of neurological consequences from repetitive head impacts (RHI), such as chronic traumatic encephalopathy. We examined CSF concentrations of total tau (t-tau), phosphorylated tau, and amyloid β1-42 and their association with RHI in former National Football League (NFL) players. The role of microglial activation (using sTREM2) was examined as a pathogenic mechanism of chronic traumatic encephalopathy. METHODS Sixty-eight former NFL players and 21 controls underwent lumbar puncture to quantify t-tau, p-tau181, amyloid β1-42, and sTREM2 in the CSF using immunoassays. The cumulative head impact index estimated RHI. RESULTS No between-group differences for CSF analytes emerged. In the former NFL players, the cumulative head impact index predicted higher t-tau concentrations (P = .041), and higher sTREM2 levels were associated with higher t-tau concentrations (P = .009). DISCUSSION In this sample of former NFL players, greater RHI and increased microglial activation were associated with higher CSF t-tau concentrations.
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Affiliation(s)
- Michael L Alosco
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Yorghos Tripodis
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Nathan G Fritts
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA
| | - Amanda Heslegrave
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK; UK Dementia Research Institute at UCL, London, UK
| | - Christine M Baugh
- Interfaculty Initiative in Health Policy, Harvard University, Boston, MA, USA
| | - Shannon Conneely
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA
| | - Megan Mariani
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA
| | - Brett M Martin
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Data Coordinating Center, Boston University School of Public Health, Boston, MA, USA
| | - Samuel Frank
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Jesse Mez
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Thor D Stein
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Departments of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA; VA Boston Healthcare System, U.S. Department of Veteran Affairs, Jamaica Plain, MA, USA; Department of Veterans Affairs Medical Center, Bedford, MA, USA
| | - Robert C Cantu
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA; Concussion Legacy Foundation, Boston, MA, USA; Department of Neurosurgery, Boston University School of Medicine, Boston, MA, USA; Department of Neurosurgery, Emerson Hospital, Concord, MA, USA
| | - Ann C McKee
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA; Departments of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA; VA Boston Healthcare System, U.S. Department of Veteran Affairs, Jamaica Plain, MA, USA; Department of Veterans Affairs Medical Center, Bedford, MA, USA
| | - Leslie M Shaw
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - John Q Trojanowski
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Henrik Zetterberg
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK; UK Dementia Research Institute at UCL, London, UK; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Robert A Stern
- Boston University Alzheimer's Disease Center and Boston University CTE Center, Boston University School of Medicine, Boston, MA, USA; Department of Neurology, Boston University School of Medicine, Boston, MA, USA; Department of Neurosurgery, Boston University School of Medicine, Boston, MA, USA; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA.
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421
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Dodd RB. An exTREMe disruption in Alzheimer's cleanup. J Biol Chem 2018; 293:12647-12648. [PMID: 30097493 DOI: 10.1074/jbc.h118.004271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Partial loss-of-function variants in the TREM2 immune receptor are associated with increased risk for Alzheimer's disease (AD) and other forms of neurodegenerative disease, but the molecular bases for these connections are unknown. Three new structures of WT and R47H mutant TREM2 immunoglobulin-like (Ig-like) domain now reveal that R47 functions to correctly position elements of the ligand-binding surface. Intriguingly, the authors also demonstrate a disruption of receptor oligomerization by the R47H mutation, suggesting a role for ligand-induced clustering in receptor signaling and resultant plaque clearance.
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Affiliation(s)
- Roger B Dodd
- From the Department of Antibody Discovery and Protein Engineering, MedImmune, Sir Aaron Klug Building, Granta Park, Cambridge CB21 6GH, United Kingdom
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422
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Konishi H, Kiyama H. Microglial TREM2/DAP12 Signaling: A Double-Edged Sword in Neural Diseases. Front Cell Neurosci 2018; 12:206. [PMID: 30127720 PMCID: PMC6087757 DOI: 10.3389/fncel.2018.00206] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/25/2018] [Indexed: 12/21/2022] Open
Abstract
Microglia are activated after neuronal injury and in neurodegenerative diseases, and trigger neuroinflammation in the central nervous system (CNS). Microglia-derived neuroinflammation has both beneficial and detrimental effects on neurons. Because the timing and magnitude of microglial activation is thought to be a critical determinant of neuronal fate, understanding the molecular mechanisms underlying microglial activation is required to enable establishment of microglia-targeted therapies for neural diseases. Plasma membrane receptors play primary roles as activators of microglia and in this review, we focus on a receptor complex involving triggering receptor expressed on myeloid cells 2 (TREM2) and DNAX-activating protein of 12 kDa (DAP12), both of which are causative genes for Nasu-Hakola disease, a dementia with bone cysts. Recent transcriptome approaches demonstrated TREM2/DAP12 signaling as the principal regulator that transforms microglia from a homeostatic to a neural disease-associated state. Furthermore, animal model studies revealed critical roles for TREM2/DAP12 in the regulation of microglial activity, including survival, phagocytosis, and cytokine production, not only in Alzheimer's disease but also in other neural diseases, such as Parkinson's disease, demyelinating disease, ischemia, and peripheral nerve injury. Intriguingly, while TREM2/DAP12-mediated microglial activation is detrimental for some diseases, including peripheral nerve injury, it is beneficial for other diseases. As the role of activated microglia differs among disease models, TREM2/DAP12 signaling may result in different outcomes in different diseases. In this review we discuss recent perspectives on the role of TREM2/DAP12 in microglia and their contribution to neural diseases.
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Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya University, Nagoya, Japan
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423
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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: 161] [Impact Index Per Article: 26.8] [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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424
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Zhang M, Zheng J, Nussinov R, Ma B. Molecular Recognition between Aβ-Specific Single-Domain Antibody and Aβ Misfolded Aggregates. Antibodies (Basel) 2018; 7:E25. [PMID: 31544877 PMCID: PMC6640678 DOI: 10.3390/antib7030025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 12/12/2022] Open
Abstract
Aβ is the toxic amyloid polypeptide responsible for Alzheimer's disease (AD). Prevention and elimination of the Aβ misfolded aggregates are the promising therapeutic strategies for the AD treatments. Gammabody, the Aβ-Specific Single-domain (VH) antibody, recognizes Aβ aggregates with high affinity and specificity and reduces their toxicities. Employing the molecular dynamics simulations, we studied diverse gammabody-Aβ recognition complexes to get insights into their structural and dynamic properties and gammabody-Aβ recognitions. Among many heterogeneous binding modes, we focused on two gammabody-Aβ recognition scenarios: recognition through Aβ β-sheet backbone and on sidechain surface. We found that the gammabody primarily uses the complementarity-determining region 3 (CDR3) loop with the grafted Aβ sequence to interact with the Aβ fibril, while CDR1/CDR2 loops have very little contact. The gammabody-Aβ complexes with backbone binding mode are more stable, explaining the gammabody's specificity towards the C-terminal Aβ sequence.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical & Biomolecular Engineering, the University of Akron, Akron, OH 44325, USA.
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, the University of Akron, Akron, OH 44325, USA.
| | - Ruth Nussinov
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Buyong Ma
- Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.
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425
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Zhou Y, Ulland TK, Colonna M. TREM2-Dependent Effects on Microglia in Alzheimer's Disease. Front Aging Neurosci 2018; 10:202. [PMID: 30038567 PMCID: PMC6046445 DOI: 10.3389/fnagi.2018.00202] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/13/2018] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD) is a late-onset dementia characterized by the deposition of amyloid plaques and formation of neurofibrillary tangles (NFTs) which lead to neuronal loss and cognitive deficits. Abnormal protein aggregates in the AD brain are also associated with reactive microglia and astrocytes. Whether this glial response is beneficial or detrimental in AD pathology is under debate. Microglia are the resident innate immune cells in the central nervous system (CNS) that survey the surrounding environment. Genome-wide association studies (GWAS) have identified the R47H variant of triggering receptor expressed on myeloid cell 2 (TREM2) as a risk factor for late-onset AD (LOAD) with an odds ratio of 4.5. TREM2 is an immunoreceptor primarily present on microglia in the CNS that binds to polyanionic molecules. The transmembrane domain of TREM2 signals through DAP12, an adaptor protein that contains an immunoreceptor tyrosine-based activation motif (ITAM), which mediates TREM2 signaling and promotes microglial activation and survival. In mouse models of AD, Trem2 haplodeficiency and deficiency lead to reduced microglial clustering around amyloid β (Aβ) plaques, suggesting TREM2 is required for plaque-associated microglial responses. Recently, TREM2 has been shown to enhance microglial metabolism through the mammalian target of rapamycin (mTOR) pathway. Although aberrant metabolism has long been associated with AD, not much was known regarding how metabolism in microglia might affect disease progression. In this review, we discuss the role of TREM2 and metabolism in AD pathology, highlighting how TREM2-mediated microglial metabolism modulates AD pathogenesis.
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Affiliation(s)
| | | | - Marco Colonna
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO, United States
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426
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Cellular Receptors of Amyloid β Oligomers (AβOs) in Alzheimer's Disease. Int J Mol Sci 2018; 19:ijms19071884. [PMID: 29954063 PMCID: PMC6073792 DOI: 10.3390/ijms19071884] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 12/15/2022] Open
Abstract
It is estimated that Alzheimer’s disease (AD) affects tens of millions of people, comprising not only suffering patients, but also their relatives and caregivers. AD is one of age-related neurodegenerative diseases (NDs) characterized by progressive synaptic damage and neuronal loss, which result in gradual cognitive impairment leading to dementia. The cause of AD remains still unresolved, despite being studied for more than a century. The hallmark pathological features of this disease are senile plaques within patients’ brain composed of amyloid beta (Aβ) and neurofibrillary tangles (NFTs) of Tau protein. However, the roles of Aβ and Tau in AD pathology are being questioned and other causes of AD are postulated. One of the most interesting theories proposed is the causative role of amyloid β oligomers (AβOs) aggregation in the pathogenesis of AD. Moreover, binding of AβOs to cell membranes is probably mediated by certain proteins on the neuronal cell surface acting as AβO receptors. The aim of our paper is to describe alternative hypotheses of AD etiology, including genetic alterations and the role of misfolded proteins, especially Aβ oligomers, in Alzheimer’s disease. Furthermore, in this review we present various putative cellular AβO receptors related to toxic activity of oligomers.
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427
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Du Y, Zhao Y, Li C, Zheng Q, Tian J, Li Z, Huang TY, Zhang W, Xu H. Inhibition of PKCδ reduces amyloid-β levels and reverses Alzheimer disease phenotypes. J Exp Med 2018; 215:1665-1677. [PMID: 29739836 PMCID: PMC5987914 DOI: 10.1084/jem.20171193] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 01/11/2018] [Accepted: 03/29/2018] [Indexed: 12/28/2022] Open
Abstract
β-amyloid protein (Aβ) plays a central role in the pathogenesis of Alzheimer disease (AD). Aβ is generated from sequential cleavage of amyloid precursor protein (APP) by β-site APP-cleaving enzyme 1 (BACE1) and the γ-secretase complex. Although activation of some protein kinase C (PKC) isoforms such as PKCα and ε has been shown to regulate nonamyloidogenic pathways and Aβ degradation, it is unclear whether other PKC isoforms are involved in APP processing/AD pathogenesis. In this study, we report that increased PKCδ levels correlate with BACE1 expression in the AD brain. PKCδ knockdown reduces BACE1 expression, BACE1-mediated APP processing, and Aβ production. Conversely, overexpression of PKCδ increases BACE1 expression and Aβ generation. Importantly, inhibition of PKCδ by rottlerin markedly reduces BACE1 expression, Aβ levels, and neuritic plaque formation and rescues cognitive deficits in an APP Swedish mutations K594N/M595L/presenilin-1 with an exon 9 deletion-transgenic AD mouse model. Our study indicates that PKCδ plays an important role in aggravating AD pathogenesis, and PKCδ may be a potential target in AD therapeutics.
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Affiliation(s)
- Ying Du
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Yingjun Zhao
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Chuan Li
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Qiuyang Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, The Collaborative Innovation Center for Brain Science, Medical College, Xiamen University, Xiamen, China
| | - Jing Tian
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Eco-Environmental Science, Shenzhen University, Shenzhen, China
| | - Zhuyi Li
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Wei Zhang
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA.,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, The Collaborative Innovation Center for Brain Science, Medical College, Xiamen University, Xiamen, China
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428
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Disease-Associated Microglia: A Universal Immune Sensor of Neurodegeneration. Cell 2018; 173:1073-1081. [DOI: 10.1016/j.cell.2018.05.003] [Citation(s) in RCA: 717] [Impact Index Per Article: 119.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/17/2018] [Accepted: 04/29/2018] [Indexed: 11/18/2022]
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