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Matteoli M. The role of microglial TREM2 in development: A path toward neurodegeneration? Glia 2024. [PMID: 38837837 DOI: 10.1002/glia.24574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 05/11/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024]
Abstract
The nervous and the immune systems undergo a continuous cross talk, starting from early development and continuing throughout adulthood and aging. Defects in this cross talk contribute to neurodevelopmental and neurodegenerative diseases. Microglia are the resident immune cells in the brain that are primarily involved in this bidirectional communication. Among the microglial genes, trem2 is a key player, controlling the functional state of microglia and being at the forefront of many processes that require interaction between microglia and other brain components, such as neurons and oligodendrocytes. The present review focuses on the early developmental window, describing the early brain processes in which TREM2 is primarily involved, including the modulation of synapse formation and elimination, the control of neuronal bioenergetic states as well as the contribution to myelination processes and neuronal circuit formation. By causing imbalances during these early maturation phases, dysfunctional TREM2 may have a striking impact on the adult brain, making it a more sensitive target for insults occurring during adulthood and aging.
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Affiliation(s)
- Michela Matteoli
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Neuro Center, IRCCS Humanitas Research Hospital, Milan, Italy
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2
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Baker PJ, Bohrer AC, Castro E, Amaral EP, Snow-Smith M, Torres-Juárez F, Gould ST, Queiroz ATL, Fukutani ER, Jordan CM, Khillan JS, Cho K, Barber DL, Andrade BB, Johnson RF, Hilligan KL, Mayer-Barber KD. The inflammatory microenvironment of the lung at the time of infection governs innate control of SARS-CoV-2 replication. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.586885. [PMID: 38585846 PMCID: PMC10996686 DOI: 10.1101/2024.03.27.586885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
SARS-CoV-2 infection leads to vastly divergent clinical outcomes ranging from asymptomatic infection to fatal disease. Co-morbidities, sex, age, host genetics and vaccine status are known to affect disease severity. Yet, how the inflammatory milieu of the lung at the time of SARS-CoV-2 exposure impacts the control of viral replication remains poorly understood. We demonstrate here that immune events in the mouse lung closely preceding SARS-CoV-2 infection significantly impact viral control and we identify key innate immune pathways required to limit viral replication. A diverse set of pulmonary inflammatory stimuli, including resolved antecedent respiratory infections with S. aureus or influenza, ongoing pulmonary M. tuberculosis infection, ovalbumin/alum-induced asthma or airway administration of defined TLR ligands and recombinant cytokines, all establish an antiviral state in the lung that restricts SARS-CoV-2 replication upon infection. In addition to antiviral type I interferons, the broadly inducible inflammatory cytokines TNFα and IL-1 precondition the lung for enhanced viral control. Collectively, our work shows that SARS-CoV-2 may benefit from an immunologically quiescent lung microenvironment and suggests that heterogeneity in pulmonary inflammation that precedes or accompanies SARS-CoV-2 exposure may be a significant factor contributing to the population-wide variability in COVID-19 disease outcomes.
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Affiliation(s)
- Paul J. Baker
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
- Current Address: Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia
| | - Andrea C. Bohrer
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Ehydel Castro
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Eduardo P. Amaral
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Maryonne Snow-Smith
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
- Human Eosinophil Section, Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda, Maryland 20892, USA
| | - Flor Torres-Juárez
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Sydnee T. Gould
- T Lymphocyte Biology Section, Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda, Maryland 20892, USA
- Current Address: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Artur T. L. Queiroz
- Multinational Organization Network Sponsoring Translational and Epidemiological Research Initiative, Salvador, Bahia 41810-710, Brazil
- Laboratory of Clinical and Translational Research, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia 40296-710, Brazil
| | - Eduardo R. Fukutani
- Multinational Organization Network Sponsoring Translational and Epidemiological Research Initiative, Salvador, Bahia 41810-710, Brazil
- Laboratory of Clinical and Translational Research, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia 40296-710, Brazil
| | - Cassandra M. Jordan
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
| | - Jaspal S. Khillan
- Mouse Genetics and Gene Modification Section, Comparative Medicine Branch, NIAID, NIH, Rockville, Maryland 20852, USA
| | - Kyoungin Cho
- Mouse Genetics and Gene Modification Section, Comparative Medicine Branch, NIAID, NIH, Rockville, Maryland 20852, USA
| | - Daniel L. Barber
- T Lymphocyte Biology Section, Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda, Maryland 20892, USA
| | - Bruno B. Andrade
- Multinational Organization Network Sponsoring Translational and Epidemiological Research Initiative, Salvador, Bahia 41810-710, Brazil
- Laboratory of Clinical and Translational Research, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia 40296-710, Brazil
| | - Reed F. Johnson
- SCV2 Virology Core, Laboratory of Viral Diseases, NIAID, NIH, Bethesda, Maryland 20892, USA
| | - Kerry L. Hilligan
- Malaghan Institute of Medical Research, Wellington 6012, New Zealand
| | - Katrin D. Mayer-Barber
- Inflammation and Innate Immunity Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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Zhong MZ, Peng T, Duarte ML, Wang M, Cai D. Updates on mouse models of Alzheimer's disease. Mol Neurodegener 2024; 19:23. [PMID: 38462606 PMCID: PMC10926682 DOI: 10.1186/s13024-024-00712-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 02/14/2024] [Indexed: 03/12/2024] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease in the United States (US). Animal models, specifically mouse models have been developed to better elucidate disease mechanisms and test therapeutic strategies for AD. A large portion of effort in the field was focused on developing transgenic (Tg) mouse models through over-expression of genetic mutations associated with familial AD (FAD) patients. Newer generations of mouse models through knock-in (KI)/knock-out (KO) or CRISPR gene editing technologies, have been developed for both familial and sporadic AD risk genes with the hope to more accurately model proteinopathies without over-expression of human AD genes in mouse brains. In this review, we summarized the phenotypes of a few commonly used as well as newly developed mouse models in translational research laboratories including the presence or absence of key pathological features of AD such as amyloid and tau pathology, synaptic and neuronal degeneration as well as cognitive and behavior deficits. In addition, advantages and limitations of these AD mouse models have been elaborated along with discussions of any sex-specific features. More importantly, the omics data from available AD mouse models have been analyzed to categorize molecular signatures of each model reminiscent of human AD brain changes, with the hope to guide future selection of most suitable models for specific research questions to be addressed in the AD field.
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Affiliation(s)
- Michael Z Zhong
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Biology, College of Arts and Science, Boston University, Boston, MA, 02215, USA
| | - Thomas Peng
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Science Research Program, Scarsdale High School, New York, NY, 10583, USA
| | - Mariana Lemos Duarte
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Research & Development, James J Peters VA Medical Center, Bronx, NY, 10468, USA.
| | - Minghui Wang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA.
- Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA.
| | - Dongming Cai
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Research & Development, James J Peters VA Medical Center, Bronx, NY, 10468, USA.
- Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Department of Neurology, N. Bud Grossman Center for Memory Research and Care, The University of Minnesota, Minneapolis, MN, 55455, USA.
- Geriatric Research Education & Clinical Center (GRECC), The Minneapolis VA Health Care System, Minneapolis, MN, 55417, USA.
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Volk Robertson K, Schleh MW, Harrison FE, Hasty AH. Microglial-specific knockdown of iron import gene, Slc11a2, blunts LPS-induced neuroinflammatory responses in a sex-specific manner. Brain Behav Immun 2024; 116:370-384. [PMID: 38141840 PMCID: PMC10874246 DOI: 10.1016/j.bbi.2023.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 12/07/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023] Open
Abstract
Neuroinflammation and microglial iron load are significant hallmarks found in several neurodegenerative diseases. In in vitro systems, microglia preferentially upregulate the iron importer, divalent metal transporter 1 (DMT1, gene name Slc11a2) in response to inflammatory stimuli, and it has been shown that iron can augment cellular inflammation, suggesting a feed-forward loop between mechanisms involved in iron import and inflammatory signaling. However, it is not understood how microglial iron import mechanisms contribute to inflammation in vivo, or whether altering a microglial iron-related gene affects the inflammatory response. These studies aimed to determine the effect of knocking down microglial iron import gene Slc11a2 on the inflammatory response in vivo. We generated a novel model of tamoxifen-inducible, microglial-specific Slc11a2 knockdown using Cx3cr1Cre-ERT2 mice. Transgenic male and female mice were administered intraperitoneal saline or lipopolysaccharide (LPS) and assessed for sickness behavior post-injection. Plasma cytokines and microglial bulk RNA sequencing (RNASeq) analyses were performed at 4 h post-LPS, and microglia were collected for gene expression analysis after 24 h. A subset of mice was assessed in a behavioral test battery following LPS-induced sickness recovery. Control male, but not female, mice significantly upregulated microglial Slc11a2 at 4 and 24 h following LPS. In Slc11a2 knockdown mice, we observed an improvement in the acute behavioral sickness response post-LPS in male, but not female, animals. Microglia from male, but not female, knockdown animals exhibited a significant decrease in LPS-provoked pro-inflammatory cytokine expression after 24 h. RNASeq data from male knockdown microglia 4 h post-LPS revealed a robust downregulation in inflammatory genes including Il6, Tnfα, and Il1β, and an increase in anti-inflammatory and homeostatic markers (e.g., Tgfbr1, Cx3cr1, and Trem2). This corresponded with a profound decrease in plasma pro-inflammatory cytokines 4 h post-LPS. At 4 h, male knockdown microglia also upregulated expression of markers of iron export, iron recycling, and iron homeostasis and decreased iron storage and import genes, along with pro-oxidant markers such as Cybb, Nos2, and Hif1α. Overall, this work elucidates how manipulating a specific gene involved in iron import in microglia alters acute inflammatory signaling and overall cell activation state in male mice. These data highlight a sex-specific link between a microglial iron import gene and the pro-inflammatory response to LPS in vivo, providing further insight into the mechanisms driving neuroinflammatory disease.
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Affiliation(s)
- Katrina Volk Robertson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Michael W Schleh
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Fiona E Harrison
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Alyssa H Hasty
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA; VA Tennessee Valley Healthcare System, Nashville, TN, USA.
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Oue H, Hatakeyama R, Ishida E, Yokoi M, Tsuga K. Experimental tooth loss affects spatial learning function and blood-brain barrier of mice. Oral Dis 2023; 29:2907-2916. [PMID: 36114741 DOI: 10.1111/odi.14379] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/28/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study aims to investigate how experimental tooth loss affected learning, memory function, and brain pathophysiology in mice. MATERIALS AND METHODS The mice (C57BL/6 J, 2-month-old, male) were divided into tooth loss and control groups. The behavioral test battery was performed at 6 and 12 months after tooth extraction. The protein levels of the tight junctions in the brains of the mice were analyzed. Hippocampal astrocyte was measured using immunohistochemical staining. RESULTS The results of behavioral tests and biochemical analysis performed during the 6 months observation period did not show significant differences between the groups. However, the escape latency in the tooth loss group was significantly longer than that in the control group at the 12 months after tooth extraction. The level of claudin-5 decreased in the tooth loss group. Additionally, hippocampal astrogliosis was found in the tooth loss group. CONCLUSIONS Experimental tooth loss reduced the level of claudin-5 and caused astrogliosis in the brains of mice, which was accompanied by deterioration of learning functions. This study may provide a new insight about the association between tooth loss and cognitive dysfunction.
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Affiliation(s)
- Hiroshi Oue
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Rie Hatakeyama
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Eri Ishida
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Miyuki Yokoi
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kazuhiro Tsuga
- Department of Advanced Prosthodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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Liu C, Nikain C, Li YM. γ-Secretase fanning the fire of innate immunity. Biochem Soc Trans 2023; 51:1597-1610. [PMID: 37449907 DOI: 10.1042/bst20221445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/29/2023] [Accepted: 07/03/2023] [Indexed: 07/18/2023]
Abstract
Innate immunity is the first line of defense against pathogens, alerting the individual cell and surrounding area to respond to this potential invasion. γ-secretase is a transmembrane protease complex that plays an intricate role in nearly every stage of this innate immune response. Through regulation of pattern recognition receptors (PRR) such as TREM2 and RAGE γ-secretase can modulate pathogen recognition. γ-secretase can act on cytokine receptors such as IFNαR2 and CSF1R to dampen their signaling capacity. While γ-secretase-mediated regulated intramembrane proteolysis (RIP) can further moderate innate immune responses through downstream signaling pathways. Furthermore, γ-secretase has also been shown to be regulated by the innate immune system through cytokine signaling and γ-secretase modulatory proteins such as IFITM3 and Hif-1α. This review article gives an overview of how γ-secretase is implicated in innate immunity and the maintenance of its responses through potentially positive and negative feedback loops.
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Affiliation(s)
- Chenge Liu
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, U.S.A
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, U.S.A
| | - Cyrus Nikain
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, U.S.A
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, U.S.A
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, U.S.A
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, U.S.A
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Yoo Y, Neumayer G, Shibuya Y, Mader MMD, Wernig M. A cell therapy approach to restore microglial Trem2 function in a mouse model of Alzheimer's disease. Cell Stem Cell 2023; 30:1043-1053.e6. [PMID: 37541210 DOI: 10.1016/j.stem.2023.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 05/10/2023] [Accepted: 07/11/2023] [Indexed: 08/06/2023]
Abstract
Alzheimer's disease (AD) remains one of the grand challenges facing human society. Much controversy exists around the complex and multifaceted pathogenesis of this prevalent disease. Given strong human genetic evidence, there is little doubt, however, that microglia play an important role in preventing degeneration of neurons. For example, loss of function of the microglial gene Trem2 renders microglia dysfunctional and causes an early-onset neurodegenerative syndrome, and Trem2 variants are among the strongest genetic risk factors for AD. Thus, restoring microglial function represents a rational therapeutic approach. Here, we show that systemic hematopoietic cell transplantation followed by enhancement of microglia replacement restores microglial function in a Trem2 mutant mouse model of AD.
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Affiliation(s)
- Yongjin Yoo
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gernot Neumayer
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yohei Shibuya
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Marc-Daniel Mader
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Biundo F, Chitu V, Gökhan Ş, Chen E, Oppong-Asare J, Stanley ER. Trem2 Enhances Demyelination in the Csf1r+/- Mouse Model of Leukoencephalopathy. Biomedicines 2023; 11:2094. [PMID: 37626591 PMCID: PMC10452898 DOI: 10.3390/biomedicines11082094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/23/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
Colony-stimulating factor-1 receptor (CSF-1R)-related leukoencephalopathy (CRL) is a neurodegenerative disease that triggers early demyelination, leading to an adult-onset dementia. Triggering receptor expressed on myeloid cells-2 (TREM2) is a microglial receptor that promotes the activation of microglia and phagocytic clearance of apoptotic neurons and myelin debris. We investigated the role of Trem2 in the demyelination observed in the Csf1r+/- mouse model of CRL. We show that elevation of Trem2 expression and callosal demyelination occur in 4-5-month-old Csf1r+/- mice, prior to the development of symptoms. Absence of Trem2 in the Csf1r+/- mouse attenuated myelin pathology and normalized microglial densities and morphology in the corpus callosum. Trem2 absence also prevented axonal degeneration and the loss of cortical layer V neurons observed in Csf1r+/- mice. Furthermore, the absence of Trem2 prevented the accumulation of myelin-derived lipids in Csf1r+/- macrophages and reduced the production of TNF-α after myelin engulfment. These data suggest that TREM2 contributes to microglial dyshomeostasis in CRL.
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Affiliation(s)
- Fabrizio Biundo
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Şölen Gökhan
- Institute for Brain Disorders and Neural Regeneration, Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Edward Chen
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jude Oppong-Asare
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - E. Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Chen B, Marquez-Nostra B, Belitzky E, Toyonaga T, Tong J, Huang Y, Cai Z. PET Imaging in Animal Models of Alzheimer’s Disease. Front Neurosci 2022; 16:872509. [PMID: 35685772 PMCID: PMC9171374 DOI: 10.3389/fnins.2022.872509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
The successful development and translation of PET imaging agents targeting β-amyloid plaques and hyperphosphorylated tau tangles have allowed for in vivo detection of these hallmarks of Alzheimer’s disease (AD) antemortem. Amyloid and tau PET have been incorporated into the A/T/N scheme for AD characterization and have become an integral part of ongoing clinical trials to screen patients for enrollment, prove drug action mechanisms, and monitor therapeutic effects. Meanwhile, preclinical PET imaging in animal models of AD can provide supportive information for mechanistic studies. With the recent advancement of gene editing technologies and AD animal model development, preclinical PET imaging in AD models will further facilitate our understanding of AD pathogenesis/progression and the development of novel treatments. In this study, we review the current state-of-the-art in preclinical PET imaging using animal models of AD and suggest future research directions.
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Karahan H, Smith DC, Kim B, Dabin LC, Al-Amin MM, Wijeratne HRS, Pennington T, Viana di Prisco G, McCord B, Lin PBC, Li Y, Peng J, Oblak AL, Chu S, Atwood BK, Kim J. Deletion of Abi3 gene locus exacerbates neuropathological features of Alzheimer's disease in a mouse model of Aβ amyloidosis. SCIENCE ADVANCES 2021; 7:eabe3954. [PMID: 34731000 PMCID: PMC8565913 DOI: 10.1126/sciadv.abe3954] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 09/16/2021] [Indexed: 05/02/2023]
Abstract
Recently, large-scale human genetics studies identified a rare coding variant in the ABI3 gene that is associated with an increased risk of Alzheimer’s disease (AD). However, pathways by which ABI3 contributes to the pathogenesis of AD are unknown. To address this question, we determined whether loss of ABI3 function affects pathological features of AD in the 5XFAD mouse model. We demonstrate that the deletion of Abi3 locus significantly increases amyloid β (Aβ) accumulation and decreases microglia clustering around the plaques. Furthermore, long-term potentiation is impaired in 5XFAD;Abi3 knockout (“Abi3−/−”) mice. Moreover, we identified marked changes in the proportion of microglia subpopulations in Abi3−/− mice using a single-cell RNA sequencing approach. Mechanistic studies demonstrate that Abi3 knockdown in microglia impairs migration and phagocytosis. Together, our study provides the first in vivo functional evidence that loss of ABI3 function may increase the risk of developing AD by affecting Aβ accumulation and neuroinflammation.
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Affiliation(s)
- Hande Karahan
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Daniel C. Smith
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Byungwook Kim
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Luke C. Dabin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Md Mamun Al-Amin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - H. R. Sagara Wijeratne
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Taylor Pennington
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Gonzalo Viana di Prisco
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brianne McCord
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Peter Bor-chian Lin
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yuxin Li
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Center for Proteomics and Metabolomics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Center for Proteomics and Metabolomics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Adrian L. Oblak
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Shaoyou Chu
- Division of Clinical Pharmacology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brady K. Atwood
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jungsu Kim
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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11
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Mendes MS, Majewska AK. An overview of microglia ontogeny and maturation in the homeostatic and pathological brain. Eur J Neurosci 2021; 53:3525-3547. [PMID: 33835613 PMCID: PMC8225243 DOI: 10.1111/ejn.15225] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/17/2021] [Accepted: 04/01/2021] [Indexed: 12/21/2022]
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and are increasingly recognized as critical players in development, brain homeostasis, and disease pathogenesis. The lifespan, maintenance, proliferation, and turnover of microglia are important factors that regulate microglial behavior and affect their roles in the CNS. However, emerging evidence suggests that microglia are morphologically and phenotypically distinct in different brain areas, at different ages, and during disease. Ongoing research focuses on understanding how microglia acquire specific phenotypes in response to extrinsic cues in the environment and how phenotypes are specified by intrinsic properties of different populations of microglia. With the development of pharmacological and genetic tools that allow the investigation of microglia in vivo, there have been considerable advances in understanding molecular signatures of both homeostatic microglia and those reacting to injury and disease. Here, we review the master gene regulators that define microglia as well as discuss the evidence that microglia are heterogeneous and fall into distinct clusters that display specific intrinsic properties and perform unique tasks in different settings. Taken together, the information presented supports the idea that microglia morphology and transcriptional heterogeneity should be considered when studying the complex nature of microglia and their roles in brain health and disease.
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Affiliation(s)
- Monique S Mendes
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
| | - Ania K Majewska
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
- Center for Visual Science, University of Rochester, Rochester, NY, USA
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12
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Magno L, Bunney TD, Mead E, Svensson F, Bictash MN. TREM2/PLCγ2 signalling in immune cells: function, structural insight, and potential therapeutic modulation. Mol Neurodegener 2021; 16:22. [PMID: 33823896 PMCID: PMC8022522 DOI: 10.1186/s13024-021-00436-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 02/24/2021] [Indexed: 01/21/2023] Open
Abstract
The central role of the resident innate immune cells of the brain (microglia) in neurodegeneration has become clear over the past few years largely through genome-wide association studies (GWAS), and has rapidly become an active area of research. However, a mechanistic understanding (gene to function) has lagged behind. That is now beginning to change, as exemplified by a number of recent exciting and important reports that provide insight into the function of two key gene products – TREM2 (Triggering Receptor Expressed On Myeloid Cells 2) and PLCγ2 (Phospholipase C gamma2) – in microglia, and their role in neurodegenerative disorders. In this review we explore and discuss these recent advances and the opportunities that they may provide for the development of new therapies.
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Affiliation(s)
- Lorenza Magno
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London, WC1E 6BT, UK.
| | - Tom D Bunney
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, UK
| | - Emma Mead
- Alzheimer's Research UK Oxford Drug Discovery Institute, Nuffield Department of Medicine Research Building, University of Oxford, Oxford, OX3 7FZ, UK
| | - Fredrik Svensson
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London, WC1E 6BT, UK
| | - Magda N Bictash
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London, WC1E 6BT, UK
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13
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Yamazaki Y, Liu CC, Yamazaki A, Shue F, Martens YA, Chen Y, Qiao W, Kurti A, Oue H, Ren Y, Li Y, Aikawa T, Cherukuri Y, Fryer JD, Asmann YW, Kim BYS, Kanekiyo T, Bu G. Vascular ApoE4 Impairs Behavior by Modulating Gliovascular Function. Neuron 2021; 109:438-447.e6. [PMID: 33321072 PMCID: PMC7864888 DOI: 10.1016/j.neuron.2020.11.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 09/22/2020] [Accepted: 11/16/2020] [Indexed: 01/19/2023]
Abstract
The ε4 allele of the apolipoprotein E gene (APOE4) is a strong genetic risk factor for Alzheimer's disease (AD) and multiple vascular conditions. ApoE is abundantly expressed in multiple brain cell types, including astrocytes, microglia, and vascular mural cells (VMCs). Here, we show that VMC-specific expression of apoE4 in mice impairs behavior and cerebrovascular function. Expression of either apoE3 or apoE4 in VMCs was sufficient to rescue the hypercholesterolemia and atherosclerosis phenotypes seen in Apoe knockout mice. Intriguingly, vascular expression of apoE4, but not apoE3, reduced arteriole blood flow, impaired spatial learning, and increased anxiety-like phenotypes. Single-cell RNA sequencing of vascular and glial cells revealed that apoE4 in VMCs was associated with astrocyte activation, while apoE3 was linked to angiogenic signature in pericytes. Together, our data support cell-autonomous effects of vascular apoE on brain homeostasis in an isoform-dependent manner, suggesting a critical contribution of vascular apoE to AD pathogenesis.
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Affiliation(s)
- Yu Yamazaki
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Akari Yamazaki
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neuroscience Graduate Program, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yuka A Martens
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yuanxin Chen
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wenhui Qiao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Aishe Kurti
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Hiroshi Oue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yingxue Ren
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Ying Li
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55902, USA
| | - Tomonori Aikawa
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yesesri Cherukuri
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL 32224, USA
| | - John D Fryer
- Neuroscience Graduate Program, Mayo Clinic, Jacksonville, FL 32224, USA; Department of Neuroscience, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Yan W Asmann
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Betty Y S Kim
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neuroscience Graduate Program, Mayo Clinic, Jacksonville, FL 32224, USA.
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14
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Vilalta A, Zhou Y, Sevalle J, Griffin JK, Satoh K, Allendorf DH, De S, Puigdellívol M, Bruzas A, Burguillos MA, Dodd RB, Chen F, Zhang Y, Flagmeier P, Needham LM, Enomoto M, Qamar S, Henderson J, Walter J, Fraser PE, Klenerman D, Lee SF, St George-Hyslop P, Brown GC. Wild-type sTREM2 blocks Aβ aggregation and neurotoxicity, but the Alzheimer's R47H mutant increases Aβ aggregation. J Biol Chem 2021; 296:100631. [PMID: 33823153 PMCID: PMC8113883 DOI: 10.1016/j.jbc.2021.100631] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/26/2021] [Accepted: 04/01/2021] [Indexed: 12/20/2022] Open
Abstract
TREM2 is a pattern recognition receptor, expressed on microglia and myeloid cells, detecting lipids and Aβ and inducing an innate immune response. Missense mutations (e.g., R47H) of TREM2 increase risk of Alzheimer's disease (AD). The soluble ectodomain of wild-type TREM2 (sTREM2) has been shown to protect against AD in vivo, but the underlying mechanisms are unclear. We show that Aβ oligomers bind to cellular TREM2, inducing shedding of the sTREM2 domain. Wild-type sTREM2 bound to Aβ oligomers (measured by single-molecule imaging, dot blots, and Bio-Layer Interferometry) inhibited Aβ oligomerization and disaggregated preformed Aβ oligomers and protofibrils (measured by transmission electron microscopy, dot blots, and size-exclusion chromatography). Wild-type sTREM2 also inhibited Aβ fibrillization (measured by imaging and thioflavin T fluorescence) and blocked Aβ-induced neurotoxicity (measured by permeabilization of artificial membranes and by loss of neurons in primary neuronal-glial cocultures). In contrast, the R47H AD-risk variant of sTREM2 is less able to bind and disaggregate oligomeric Aβ but rather promotes Aβ protofibril formation and neurotoxicity. Thus, in addition to inducing an immune response, wild-type TREM2 may protect against amyloid pathology by the Aβ-induced release of sTREM2, which blocks Aβ aggregation and neurotoxicity. In contrast, R47H sTREM2 promotes Aβ aggregation into protofibril that may be toxic to neurons. These findings may explain how wild-type sTREM2 apparently protects against AD in vivo and why a single copy of the R47H variant gene is associated with increased AD risk.
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Affiliation(s)
- Anna Vilalta
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ye Zhou
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - Jean Sevalle
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - Jennifer K Griffin
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - Kanayo Satoh
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - David H Allendorf
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Suman De
- AstraZeneca, Cambridge, United Kingdom
| | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Arturas Bruzas
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Miguel A Burguillos
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom; Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Roger B Dodd
- AstraZeneca, Cambridge, United Kingdom; Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Fusheng Chen
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - Yalun Zhang
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - Patrick Flagmeier
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Lisa-Maria Needham
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network, Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Seema Qamar
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - James Henderson
- Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Jochen Walter
- Molecular Cell Biology, Department of Neurology, University of Bonn, Bonn, Germany
| | - Paul E Fraser
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Cambridge Dementia Research Institute, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Steven F Lee
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Peter St George-Hyslop
- Departments of Medicine (Neurology) and Medical Biophysics, University of Toronto and University Health Network, Toronto, Ontario, Canada; Cambridge Institute for Medical Research, Cambridge, United Kingdom.
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
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15
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Audrain M, Haure-Mirande JV, Mleczko J, Wang M, Griffin JK, St George-Hyslop PH, Fraser P, Zhang B, Gandy S, Ehrlich ME. Reactive or transgenic increase in microglial TYROBP reveals a TREM2-independent TYROBP-APOE link in wild-type and Alzheimer's-related mice. Alzheimers Dement 2020; 17:149-163. [PMID: 33314529 PMCID: PMC7938663 DOI: 10.1002/alz.12256] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/19/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022]
Abstract
Introduction Microglial TYROBP (DAP12) is a network hub and driver in sporadic late‐onset Alzheimer's disease (AD). TYROBP is a cytoplasmic adaptor for TREM2 and other receptors, but little is known about its roles and actions in AD. Herein, we demonstrate that endogenous Tyrobp transcription is specifically increased in recruited microglia. Methods Using a novel transgenic mouse overexpressing TYROBP in microglia, we observed a decrease of the amyloid burden and an increase of TAU phosphorylation stoichiometry when crossed with APP/PSEN1 or MAPTP301S mice, respectively. Characterization of these mice revealed Tyrobp‐related modulation of apolipoprotein E (Apoe) transcription. We also showed that Tyrobp and Apoe mRNAs were increased in Trem2‐null microglia recruited around either amyloid beta deposits or a cortical stab injury. Conversely, microglial Apoe transcription was dramatically diminished when Tyrobp was absent. Conclusions Our results provide evidence that TYROBP‐APOE signaling does not require TREM2 and could be an initiating step in establishment of the disease‐associated microglia (DAM) phenotype.
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Affiliation(s)
- Mickael Audrain
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Justyna Mleczko
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Minghui Wang
- Department of Genetics and Genomic Sciences and Icahn Institute of Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jennifer K Griffin
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Peter H St George-Hyslop
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Paul Fraser
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Bin Zhang
- Department of Genetics and Genomic Sciences and Icahn Institute of Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Sam Gandy
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,National Institute on Aging-Designated Alzheimer's Disease Research Center and Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Research and Development, James J. Peters Veterans Affairs Medical Center, Bronx, New York, USA
| | - Michelle E Ehrlich
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Genetics and Genomic Sciences and Icahn Institute of Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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16
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Konishi H, Kiyama H. Non-pathological roles of microglial TREM2/DAP12: TREM2/DAP12 regulates the physiological functions of microglia from development to aging. Neurochem Int 2020; 141:104878. [DOI: 10.1016/j.neuint.2020.104878] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 01/01/2023]
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17
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Hall-Roberts H, Agarwal D, Obst J, Smith TB, Monzón-Sandoval J, Di Daniel E, Webber C, James WS, Mead E, Davis JB, Cowley SA. TREM2 Alzheimer's variant R47H causes similar transcriptional dysregulation to knockout, yet only subtle functional phenotypes in human iPSC-derived macrophages. Alzheimers Res Ther 2020; 12:151. [PMID: 33198789 PMCID: PMC7667762 DOI: 10.1186/s13195-020-00709-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 10/20/2020] [Indexed: 01/21/2023]
Abstract
BACKGROUND TREM2 is a microglial cell surface receptor, with risk mutations linked to Alzheimer's disease (AD), including R47H. TREM2 signalling via SYK aids phagocytosis, chemotaxis, survival, and changes to microglial activation state. In AD mouse models, knockout (KO) of TREM2 impairs microglial clustering around amyloid and prevents microglial activation. The R47H mutation is proposed to reduce TREM2 ligand binding. We investigated cell phenotypes of the R47H mutant and TREM2 KO in a model of human microglia, and compared their transcriptional signatures, to determine the mechanism by which R47H TREM2 disrupts function. METHODS We generated human microglia-like iPSC-macrophages (pMac) from isogenic induced pluripotent stem cell (iPSC) lines, with homozygous R47H mutation or TREM2 knockout (KO). We firstly validated the effect of the R47H mutant on TREM2 surface and subcellular localization in pMac. To assess microglial phenotypic function, we measured phagocytosis of dead neurons, cell morphology, directed migration, survival, and LPS-induced inflammation. We performed bulk RNA-seq, comparing significant differentially expressed genes (DEGs; p < 0.05) between the R47H and KO versus WT, and bioinformatically predicted potential upstream regulators of TREM2-mediated gene expression. RESULTS R47H modified surface expression and shedding of TREM2, but did not impair TREM2-mediated signalling, or gross phenotypes that were dysregulated in the TREM2 KO (phagocytosis, motility, survival). However, altered gene expression in the R47H TREM2 pMac overlapped by 90% with the TREM2 KO and was characterised by dysregulation of genes involved with immunity, proliferation, activation, chemotaxis, and adhesion. Downregulated mediators of ECM adhesion included the vitronectin receptor αVβ3, and consequently, R47H TREM2 pMac adhered weakly to vitronectin compared with WT pMac. To counteract these transcriptional defects, we investigated TGFβ1, as a candidate upstream regulator. TGFβ1 failed to rescue vitronectin adhesion of pMac, although it improved αVβ3 expression. CONCLUSIONS The R47H mutation is not sufficient to cause gross phenotypic defects of human pMac under standard culture conditions. However, overlapping transcriptional defects with TREM2 KO supports the hypothesised partial loss-of-function effects of the R47H mutation. Furthermore, transcriptomics can guide us to more subtle phenotypic defects in the R47H cells, such as reduced cell adhesion, and can be used to predict targets for therapeutic intervention.
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Affiliation(s)
- Hazel Hall-Roberts
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Devika Agarwal
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS UK
| | - Juliane Obst
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Thomas B. Smith
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | | | - Elena Di Daniel
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Caleb Webber
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ UK
| | - William S. James
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
| | - Emma Mead
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - John B. Davis
- Nuffield Department of Medicine Research Building, Alzheimer’s Research UK Oxford Drug Discovery Institute, University of Oxford, Oxford, OX3 7FZ UK
| | - Sally A. Cowley
- James Martin Stem Cell Facility, Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE UK
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18
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Loss of TREM2 Confers Resilience to Synaptic and Cognitive Impairment in Aged Mice. J Neurosci 2020; 40:9552-9563. [PMID: 33139402 DOI: 10.1523/jneurosci.2193-20.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/12/2020] [Accepted: 10/27/2020] [Indexed: 11/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor exclusively expressed by microglia in the brain, modulates microglial immune homeostasis. Human genetic studies have shown that the loss-of-function mutations in TREM2 signaling are strongly associated with an elevated risk of age-related neurodegenerative diseases including Alzheimer's disease (AD). Numerous studies have investigated the impact of TREM2 deficiency in the pathogenic process of AD. However, the role of TREM2 in shaping neuronal and cognitive function during normal aging is underexplored. In the present study, we employed behavioral, electrophysiological, and biochemical approaches to assess cognitive and synaptic function in male and female young and aged TREM2-deficient (Trem2-/-) mice compared with age-matched, sex-matched, and genetic background-matched wild-type (WT) C57BL/6J controls. Young Trem2-/- mice exhibited normal cognitive function and synaptic plasticity but had increased dendritic spine density compared with young WT. Unexpectedly, aged Trem2-/- mice showed superior cognitive performance compared with aged WT controls. Consistent with the behavioral data, aged Trem2-/- mice displayed significantly enhanced hippocampal long-term potentiation (LTP) and increased dendritic spine density and synaptic markers compared with aged WT mice. Taken together, these findings suggest that loss of TREM2 affects the neuronal structure and confers resilience to age-related synaptic and cognitive impairment during non-pathogenic aging.SIGNIFICANCE STATEMENT Microglia are innate immune cells of the brain that orchestrates neurodevelopment, synaptic function, and immune response to environmental stimuli. Microglial triggering receptor expressed on myeloid cells 2 (TREM2) signaling plays pivotal roles in regulating these functions and loss of TREM2 signaling leads to increased risk of developing age-related neurologic disorders. However, the neurologic role of TREM2 in normal aging is poorly understood. The results of the present study unveil the positive impacts of TREM2 deficiency on cognitive and synaptic function during aging and suggest that TREM2 may exert detrimental effects on neuronal function. The possibility of age-related negative impacts from TREM2 is critically important since TREM2 has emerged as a major therapeutic target for Alzheimer's dementia.
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19
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Jadhav VS, Lin PBC, Pennington T, Di Prisco GV, Jannu AJ, Xu G, Moutinho M, Zhang J, Atwood BK, Puntambekar SS, Bissel SJ, Oblak AL, Landreth GE, Lamb BT. Trem2 Y38C mutation and loss of Trem2 impairs neuronal synapses in adult mice. Mol Neurodegener 2020; 15:62. [PMID: 33115519 PMCID: PMC7594478 DOI: 10.1186/s13024-020-00409-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 10/01/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Triggering receptor expressed on myeloid cells 2 (TREM2) is expressed in the brain exclusively on microglia and genetic variants are linked to neurodegenerative diseases including Alzheimer's disease (AD), frontotemporal dementia (FTD) and Nasu Hakola Disease (NHD). The Trem2 variant R47H, confers substantially elevated risk of developing late onset Alzheimer's disease, while NHD-linked Trem2 variants like Y38C, are associated with development of early onset dementia with white matter pathology. However, it is not known how these Trem2 species, predisposes individuals to presenile dementia. METHODS To investigate if Trem2 Y38C or loss of Trem2 alters neuronal function we generated a novel mouse model to introduce the NHD Trem2 Y38C variant in murine Trem2 using CRISPR/Cas9 technology. Trem2Y38C/Y38C and Trem2-/- mice were assessed for Trem2 expression, differentially expressed genes, synaptic protein levels and synaptic plasticity using biochemical, electrophysiological and transcriptomic approaches. RESULTS While mice harboring the Trem2 Y38C exhibited normal expression levels of TREM2, the pathological outcomes phenocopied Trem2-/- mice at 6 months. Transcriptomic analysis revealed altered expression of neuronal and oligodendrocytes/myelin genes. We observed regional decreases in synaptic protein levels, with the most affected synapses in the hippocampus. These alterations were associated with reduced synaptic plasticity. CONCLUSION Our findings provide in vivo evidence that Trem2 Y38C disrupts normal TREM2 functions. Trem2Y38C/Y38C and Trem2-/- mice demonstrated altered gene expression, changes in microglia morphology, loss of synaptic proteins and reduced hippocampal synaptic plasticity at 6 months in absence of any pathological triggers like amyloid. This suggests TREM2 impacts neuronal functions providing molecular insights on the predisposition of individuals with TREM2 variants resulting in presenile dementia.
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Affiliation(s)
- Vaishnavi S Jadhav
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Peter B C Lin
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Taylor Pennington
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Gonzalo Viana Di Prisco
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Asha Jacob Jannu
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 462020, USA
| | - Guixiang Xu
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Miguel Moutinho
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Jie Zhang
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Brady K Atwood
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Pharmacology and Toxicology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Shweta S Puntambekar
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Stephanie J Bissel
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Adrian L Oblak
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Gary E Landreth
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
- Department of Anatomy and Cell Biology, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA
| | - Bruce T Lamb
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Medical and Molecular Genetics, Indiana University, School of Medicine, Indianapolis, IN, 46202, USA.
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20
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Korvatska O, Kiianitsa K, Ratushny A, Matsushita M, Beeman N, Chien WM, Satoh JI, Dorschner MO, Keene CD, Bammler TK, Bird TD, Raskind WH. Triggering Receptor Expressed on Myeloid Cell 2 R47H Exacerbates Immune Response in Alzheimer's Disease Brain. Front Immunol 2020; 11:559342. [PMID: 33101276 PMCID: PMC7546799 DOI: 10.3389/fimmu.2020.559342] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/25/2020] [Indexed: 01/11/2023] Open
Abstract
The R47H variant in the microglial triggering receptor expressed on myeloid cell 2 (TREM2) receptor is a strong risk factor for Alzheimer’s disease (AD). To characterize processes affected by R47H, we performed an integrative network analysis of genes expressed in brains of AD patients with R47H, sporadic AD without the variant, and patients with polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), systemic disease with early-onset dementia caused by loss-of-function mutations in TREM2 or its adaptor TYRO protein tyrosine kinase-binding protein (TYROBP). Although sporadic AD had few perturbed microglial and immune genes, TREM2 R47H AD demonstrated upregulation of interferon type I response and pro-inflammatory cytokines accompanied by induction of NKG2D stress ligands. In contrast, PLOSL had distinct sets of highly perturbed immune and microglial genes that included inflammatory mediators, immune signaling, cell adhesion, and phagocytosis. TREM2 knockout (KO) in THP1, a human myeloid cell line that constitutively expresses the TREM2- TYROBP receptor, inhibited response to the viral RNA mimetic poly(I:C) and phagocytosis of amyloid-beta oligomers; overexpression of ectopic TREM2 restored these functions. Compared with wild-type protein, R47H TREM2 had a higher stimulatory effect on the interferon type I response signature. Our findings point to a role of the TREM2 receptor in the control of the interferon type I response in myeloid cells and provide insight regarding the contribution of R47H TREM2 to AD pathology.
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Affiliation(s)
- Olena Korvatska
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States
| | - Kostantin Kiianitsa
- Department of Immunology, University of Washington, Seattle, WA, United States
| | - Alexander Ratushny
- Seattle Biomedical Research Institute and Institute for Systems Biology, Seattle, WA, United States
| | - Mark Matsushita
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, United States
| | - Neal Beeman
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, United States
| | - Wei-Ming Chien
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, United States
| | - Jun-Ichi Satoh
- Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Tokyo, Japan
| | - Michael O Dorschner
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States
| | - Theo K Bammler
- Department of Environmental and Occupational Health Sciences, Seattle, WA, United States
| | - Thomas D Bird
- Department of Neurology, University of Washington, Seattle, WA, United States.,Geriatric Research, Education and Clinical Center, Veteran Affairs Puget Sound Health Care System, Seattle, WA, United States
| | - Wendy H Raskind
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States.,Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, United States.,Geriatric Research, Education and Clinical Center, Veteran Affairs Puget Sound Health Care System, Seattle, WA, United States.,Mental Illness Research, Education and Clinical Center, Department of Veteran Affairs, Seattle, WA, United States
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21
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von Saucken VE, Jay TR, Landreth GE. The effect of amyloid on microglia-neuron interactions before plaque onset occurs independently of TREM2 in a mouse model of Alzheimer's disease. Neurobiol Dis 2020; 145:105072. [PMID: 32890775 PMCID: PMC7808254 DOI: 10.1016/j.nbd.2020.105072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/13/2020] [Accepted: 08/30/2020] [Indexed: 12/23/2022] Open
Abstract
Genetic studies identified mutations in several immune-related genes that confer increased risk for developing Alzheimer’s disease (AD), suggesting a key role for microglia in AD pathology. Microglia are recruited to and actively modulate the local toxicity of amyloid plaques in models of AD through these cells’ transcriptional and functional reprogramming to a disease-associated phenotype. However, it remains unknown whether microglia actively respond to amyloid accumulation before plaque deposition in AD. We compared microglial interactions with neurons that exhibit amyloid accumulation to those that do not in 1-month-old 5XFAD mice to determine which aspects of microglial morphology and function are altered by early 6E10+ amyloid accumulation. We provide evidence of preferential microglial process engagement of amyloid laden neurons. Microglia, on exposure to amyloid, also increase their internalization of neurites even before plaque onset. Unexpectedly, we found that triggering receptor expressed on myeloid cells 2 (TREM2), which is critical for microglial responses to amyloid plaque pathology later in disease, is not required for enhanced microglial interactions with neurons or neurite internalization early in disease. However, TREM2 was still required for early morphological changes exhibited by microglia. These data demonstrate that microglia sense and respond to amyloid accumulation before plaques form using a distinct mechanism from the TREM2-dependent pathway required later in disease.
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Affiliation(s)
- Victoria E von Saucken
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Taylor R Jay
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Gary E Landreth
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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22
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Faridar A, Thome AD, Zhao W, Thonhoff JR, Beers DR, Pascual B, Masdeu JC, Appel SH. Restoring regulatory T-cell dysfunction in Alzheimer's disease through ex vivo expansion. Brain Commun 2020; 2:fcaa112. [PMID: 32954348 PMCID: PMC7472911 DOI: 10.1093/braincomms/fcaa112] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/30/2020] [Accepted: 06/26/2020] [Indexed: 12/16/2022] Open
Abstract
Inflammation is a significant component of Alzheimer’s disease pathology. While neuroprotective microglia are important for containment/clearance of Amyloid plaques and maintaining neuronal survival, Alzheimer inflammatory microglia may play a detrimental role by eliciting tau pathogenesis and accelerating neurotoxicity. Regulatory T cells have been shown to suppress microglia-mediated inflammation. However, the role of regulatory T cells in ameliorating the proinflammatory immune response in Alzheimer’s disease requires further investigation. Forty-six patients with Alzheimer disease, 42 with mild cognitive impairment and 41 healthy controls were studied. The phenotypes of peripheral regulatory T cells were assessed with multicolour flow cytometry. Regulatory T cells were co-cultured with responder T cells and proliferation was determined by 3H-thymidine incorporation. In separate experiments, regulatory T cells were added to induced pluripotent stem cell-derived pro-inflammatory macrophages and changes in interleukin-6/tumour necrosis-alpha transcripts and protein levels were measured. Freshly isolated regulatory T cells were expanded ex vivo in the presence of CD3/CD28 expander beads, interleukin-2 and rapamycin to promote their suppressive function. We found that the suppressive function of regulatory T cells on responder T-cell proliferation was compromised at the Alzheimer disease stage, compared with mild cognitive impairment and healthy controls. CD25 mean fluorescence intensity in regulatory T-cell population was also reduced in Alzheimer dementia patients. Regulatory T cells did not suppress pro-inflammatory macrophages at baseline. Following ex vivo expansion, regulatory T-cell suppression of responder T-cell proliferation and pro-inflammatory macrophage activation increased in both patients and controls. Expanded regulatory T cells exerted their immunoregulatory function on pro-inflammatory macrophages through a contact-mediated mechanism. In conclusion, regulatory T-cell immunophenotype and function are compromised in Alzheimer’s disease. Following ex vivo expansion, the immunomodulatory function of regulatory T cells is enhanced even at advanced stages of Alzheimer’s disease. Restoration of regulatory T-cell function could be explored as a means to modulate the inflammatory status of Alzheimer’s disease.
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Affiliation(s)
- Alireza Faridar
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Aaron D Thome
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Weihua Zhao
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Jason R Thonhoff
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - David R Beers
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Belen Pascual
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Joseph C Masdeu
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
| | - Stanley H Appel
- Stanley H. Appel Department of Neurology, Houston Methodist Neurological Institute, Houston, TX 77030, USA
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23
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Rong Z, Cheng B, Zhong L, Ye X, Li X, Jia L, Li Y, Shue F, Wang N, Cheng Y, Huang X, Liu CC, Fryer JD, Wang X, Zhang YW, Zheng H. Activation of FAK/Rac1/Cdc42-GTPase signaling ameliorates impaired microglial migration response to Aβ 42 in triggering receptor expressed on myeloid cells 2 loss-of-function murine models. FASEB J 2020; 34:10984-10997. [PMID: 32613609 DOI: 10.1096/fj.202000550rr] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 12/20/2022]
Abstract
Mutation of Triggering receptor expressed on myeloid cells 2 (TREM2) impairs the response of microglia to amyloid-β (Aβ) pathology in Alzheimer's disease (AD), although the mechanism governing TREM2-regulated microglia recruitment to Aβ plaques remains unresolved. Here, we confirm that TREM2 mutation attenuates microglial migration. Then, using Trem2-/- mice and an R47H variant mouse model for AD generated for this study, we show that TREM2 deficiency or the AD-associated R47H mutation results in inhibition of FAK and Rac1/Cdc42-GTPase signaling critical for cell migration. Intriguingly, treatment with CN04, a Rac1/Cdc42-GTPase activator, partially enhances microglial migration in response to oligomeric Aβ42 in Trem2-/- or R47H microglia both in vitro and in vivo. Our study shows that the dysfunction of microglial migration in the AD-associated TREM2 R47H variant is caused by FAK/Rac1/Cdc42 signaling disruption, and that activation of this signaling ameliorates impaired microglial migration response to Aβ42 , suggesting a therapeutic target for R47H-bearing patients with high risk of AD.
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Affiliation(s)
- Zhouyi Rong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Baoying Cheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Li Zhong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xiaowen Ye
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xin Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Lin Jia
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Na Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yiyun Cheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Xiaohua Huang
- Basic Medical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Xin Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.,State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, Shenzhen, China.,Basic Medical Sciences, School of Medicine, Xiamen University, Xiamen, China
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24
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Ren S, Yao W, Tambini MD, Yin T, Norris KA, D'Adamio L. Microglia TREM2R47H Alzheimer-linked variant enhances excitatory transmission and reduces LTP via increased TNF-α levels. eLife 2020; 9:57513. [PMID: 32579116 PMCID: PMC7338048 DOI: 10.7554/elife.57513] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/23/2020] [Indexed: 01/09/2023] Open
Abstract
To study the mechanisms by which the p.R47H variant of the microglia gene and Alzheimer’s disease (AD) risk factor TREM2 increases dementia risk, we created Trem2R47H KI rats. Trem2R47H rats were engineered to produce human Aβ to define human-Aβ-dependent and -independent pathogenic mechanisms triggered by this variant. Interestingly, pre- and peri-adolescent Trem2R47H rats present increased brain concentrations of TNF-α, augmented glutamatergic transmission, suppression of Long-term-Potentiation (LTP), an electrophysiological surrogate of learning and memory, but normal Aβ levels. Acute reduction of TNF-α activity with a neutralizing anti-TNF-α antibody occludes the boost in amplitude of glutamatergic transmission and LTP suppression observed in young Trem2R47H/R47H rats. Thus, the microglia-specific pathogenic Trem2 variant boosts glutamatergic neuronal transmission and suppresses LTP by increasing brain TNF-α concentrations, directly linking microglia to neuronal dysfunction. Future studies will determine whether this phenomenon represents an early, Aβ-independent pathway that facilitates dementia pathogenesis in humans.
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Affiliation(s)
- Siqiang Ren
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Wen Yao
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Marc D Tambini
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Tao Yin
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Kelly A Norris
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
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25
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Trem2 Deletion Reduces Late-Stage Amyloid Plaque Accumulation, Elevates the Aβ42:Aβ40 Ratio, and Exacerbates Axonal Dystrophy and Dendritic Spine Loss in the PS2APP Alzheimer's Mouse Model. J Neurosci 2020; 40:1956-1974. [PMID: 31980586 PMCID: PMC7046459 DOI: 10.1523/jneurosci.1871-19.2019] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/08/2019] [Accepted: 12/23/2019] [Indexed: 01/17/2023] Open
Abstract
TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of β-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. Plaque abundance was elevated in PS2APP;Trem2ko females at 6–7 months; but by 12 or 19–22 months of age, it was notably diminished in female and male PS2APP;Trem2ko mice, respectively. Across all ages, plaque morphology was more diffuse in PS2APP;Trem2ko brains, and the Aβ42:Aβ40 ratio was elevated. The amount of soluble, fibrillar Aβ oligomers also increased in PS2APP;Trem2ko hippocampi. Associated with these changes, axonal dystrophy was exacerbated from 6 to 7 months onward in PS2APP;Trem2ko mice, notwithstanding the reduced plaque load at later ages. PS2APP;Trem2ko mice also exhibited more dendritic spine loss around plaque and more neurofilament light chain in CSF. Thus, aggravated neuritic dystrophy is a more consistent outcome of Trem2 deficiency than amyloid plaque load, suggesting that the microglial packing of Aβ into dense plaque is an important neuroprotective activity. SIGNIFICANCE STATEMENT Genetic studies indicate that TREM2 gene mutations confer increased Alzheimer's disease (AD) risk. We studied the effects of Trem2 deletion in the PS2APP mouse AD model, in which overproduction of Aβ peptide leads to amyloid plaque formation and associated neuritic dystrophy. Interestingly, neuritic dystrophies were intensified in the brains of Trem2-deficient mice, despite these mice displaying reduced plaque accumulation at later ages (12–22 months). Microglial clustering around plaques was impaired, plaques were more diffuse, and the Aβ42:Aβ40 ratio and amount of soluble, fibrillar Aβ oligomers were elevated in Trem2-deficient brains. These results suggest that the Trem2-dependent compaction of Aβ into dense plaques is a protective microglial activity, limiting the exposure of neurons to toxic Aβ species.
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26
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Jay TR, von Saucken VE, Muñoz B, Codocedo JF, Atwood BK, Lamb BT, Landreth GE. TREM2 is required for microglial instruction of astrocytic synaptic engulfment in neurodevelopment. Glia 2019; 67:1873-1892. [PMID: 31265185 DOI: 10.1002/glia.23664] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/03/2019] [Accepted: 06/05/2019] [Indexed: 01/08/2023]
Abstract
Variants in the microglial receptor TREM2 confer risk for multiple neurodegenerative diseases. However, it remains unknown how this receptor functions on microglia to modulate these diverse neuropathologies. To understand the role of TREM2 on microglia more generally, we investigated changes in microglial function in Trem2-/- mice. We found that loss of TREM2 impairs normal neurodevelopment, resulting in reduced synapse number across the cortex and hippocampus in 1-month-old mice. This reduction in synapse number was not due directly to alterations in interactions between microglia and synapses. Rather, TREM2 was required for microglia to limit synaptic engulfment by astrocytes during development. While these changes were largely normalized later in adulthood, high fat diet administration was sufficient to reinitiate TREM2-dependent modulation of synapse loss. Together, this identifies a novel role for microglia in instructing synaptic pruning by astrocytes to broadly regulate appropriate synaptic refinement, and suggests novel candidate mechanisms for how TREM2 and microglia could influence synaptic loss in brain injury and disease.
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Affiliation(s)
- Taylor R Jay
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
| | - Victoria E von Saucken
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Braulio Muñoz
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana
| | - Juan F Codocedo
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Brady K Atwood
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Bruce T Lamb
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Gary E Landreth
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
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27
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Karanfilian L, Tosto MG, Malki K. The role of TREM2 in Alzheimer's disease; evidence from transgenic mouse models. Neurobiol Aging 2019; 86:39-53. [PMID: 31727362 DOI: 10.1016/j.neurobiolaging.2019.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is a currently incurable neurodegenerative disorder. Several genetic studies have identified a rare variant of triggering receptor expressed on myeloid cells 2 (TREM2) as a risk factor for AD. TREM2 is thought to trigger the microglial response to amyloid plaques. Mouse models have helped elucidate mechanisms through which TREM2 affects microglial function and modulates pathological features of AD. A synthesis of the 35 mouse-model studies included in this review indicates that TREM2 modulates amyloid plaque composition and deposition, microglial morphology and proliferation, neuroinflammation, and tau phosphorylation. TREM2 also acts as a sensor for anionic lipids exposed during neuronal apoptosis and Aβ deposition, may improve spatial abilities and memory, and protect against apoptosis. In early stages of AD, TREM2 knock-down reduces expression of proinflammatory cytokines and upregulates anti-inflammatory cytokines but in later stages, TREM2 may contribute to the disease by aggravating neuroinflammation. The results provide insight into TREM2-related mechanisms that may be associated with AD in humans and may aid future development of disease-modifying pharmacological treatments targeting TREM2.
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Affiliation(s)
- Lucine Karanfilian
- King's College London at the Institute of Psychiatry, Psychology and Neuroscience (IOPPN), London, UK
| | - Maria Grazia Tosto
- King's College London at the Institute of Psychiatry, Psychology and Neuroscience (IOPPN), London, UK
| | - Karim Malki
- King's College London at the Institute of Psychiatry, Psychology and Neuroscience (IOPPN), London, UK; UCB Pharma, Statistical Sciences and Innovation, Slough, UK.
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28
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Lessard CB, Malnik SL, Zhou Y, Ladd TB, Cruz PE, Ran Y, Mahan TE, Chakrabaty P, Holtzman DM, Ulrich JD, Colonna M, Golde TE. High-affinity interactions and signal transduction between Aβ oligomers and TREM2. EMBO Mol Med 2019; 10:emmm.201809027. [PMID: 30341064 PMCID: PMC6220267 DOI: 10.15252/emmm.201809027] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Rare coding variants in the triggering receptor expressed on myeloid cells 2 (TREM2) are associated with increased risk for Alzheimer's disease (AD), but how they confer this risk remains uncertain. We assessed binding of TREM2, AD‐associated TREM2 variants to various forms of Aβ and APOE in multiple assays. TREM2 interacts directly with various forms of Aβ, with highest affinity interactions observed between TREM2 and soluble Aβ42 oligomers. High‐affinity binding of TREM2 to Aβ oligomers is characterized by very slow dissociation. Pre‐incubation with Aβ is shown to block the interaction of APOE. In cellular assays, AD‐associated variants of TREM2 reduced the amount of Aβ42 internalized, and in NFAT assay, the R47H and R62H variants decreased NFAT signaling activity in response to Aβ42. These studies demonstrate i) a high‐affinity interaction between TREM2 and Aβ oligomers that can block interaction with another TREM2 ligand and ii) that AD‐associated TREM2 variants bind Aβ with equivalent affinity but show loss of function in terms of signaling and Aβ internalization.
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Affiliation(s)
- Christian B Lessard
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Samuel L Malnik
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Yingyue Zhou
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Thomas E Mahan
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Paramita Chakrabaty
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA.,McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Jason D Ulrich
- Department of Neurology, Hope Center for Neurological Disorders, Knight ADRC, Washington University School of Medicine, St. Louis, MO, USA
| | - Marco Colonna
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL, USA .,McKnight Brain Institute, University of Florida, Gainesville, FL, USA
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29
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Yang FC, Chiu PY, Chen Y, Mak TW, Chen NJ. TREM-1-dependent M1 macrophage polarization restores intestinal epithelium damaged by DSS-induced colitis by activating IL-22-producing innate lymphoid cells. J Biomed Sci 2019; 26:46. [PMID: 31189465 PMCID: PMC6560756 DOI: 10.1186/s12929-019-0539-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/28/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Triggering receptor expressed on myeloid cells-1 (TREM-1) is highly expressed on macrophages in inflamed intestines and reportedly promotes inflammatory bowel disease (IBD) by augmenting pro-inflammatory responses. To study the mechanism mediated by TREM-1 on macrophages, we generated an independent TREM-1 deficient mouse. METHODS Acute colitis was induced in C57BL/6 and TREM-1-deficient mice by the administration of dextran sodium sulfate (DSS). Colonic lamina propria immune cell composition and cytokines were analyzed. An innate lymphoid cell (ILC) co-culture experiment with macrophages was used to analyze IL-22 levels. Exogenous IL-22 and TREM-1-expressing macrophages were supplied to TREM-1-deficient mice for examining their effects on intestinal barrier integrity. RESULTS In inflamed colons, TREM-1 loss compromised the activation of ILC3 and their production of IL-22, which is required for intestinal barrier integrity. ILC3-mediated IL-22 production depends on IL-1β secreted by M1-polarized macrophages, and we found that TREM-1 deficiency results in a decreased number of IL-1β producing-M1 macrophages in colons exposed to DSS. Accordingly, DSS-mediated damage was ameliorated by supplying exogenous IL-22 and TREM-1-expressing macrophages to TREM-1-deficient mice. CONCLUSIONS TREM-1 plays a crucial role in regulating IL-22 production by ILC3 through modulating M1-macrophage polarization during DSS-induced acute colitis.
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Affiliation(s)
- Fu-Chen Yang
- Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Po-Yuan Chiu
- Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, No.155, Sec.2, Linong Street, Taipei, Taiwan
| | - Yun Chen
- Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Tak W. Mak
- The Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, University Health Network and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2C1 Canada
| | - Nien-Jung Chen
- Institute of Microbiology and Immunology, School of Life Sciences, National Yang-Ming University, No.155, Sec.2, Linong Street, Taipei, Taiwan
- Cancer Progression Research Center, National Yang-Ming University, Taipei, Taiwan
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30
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Integrative approach to sporadic Alzheimer's disease: deficiency of TYROBP in a tauopathy mouse model reduces C1q and normalizes clinical phenotype while increasing spread and state of phosphorylation of tau. Mol Psychiatry 2019; 24:1383-1397. [PMID: 30283031 PMCID: PMC6447470 DOI: 10.1038/s41380-018-0258-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/02/2018] [Accepted: 08/15/2018] [Indexed: 01/01/2023]
Abstract
TYROBP/DAP12 forms complexes with ectodomains of immune receptors (TREM2, SIRPβ1, CR3) associated with Alzheimer's disease (AD) and is a network hub and driver in the complement subnetwork identified by multi-scale gene network studies of postmortem human AD brain. Using transgenic or viral approaches, we characterized in mice the effects of TYROBP deficiency on the phenotypic and pathological evolution of tauopathy. Biomarkers usually associated with worsening clinical phenotype (i.e., hyperphosphorylation and increased tauopathy spreading) were unexpectedly increased in MAPTP301S;Tyrobp-/- mice despite the improved learning behavior and synaptic function relative to controls with normal levels of TYROBP. Notably, levels of complement cascade initiator C1q were reduced in MAPTP301S;Tyrobp-/- mice, consistent with the prediction that C1q reduction exerts a neuroprotective effect. These observations suggest a model wherein TYROBP-KO-(knock-out)-associated reduction in C1q is associated with normalized learning behavior and electrophysiological properties in tauopathy model mice despite a paradoxical evolution of biomarker signatures usually associated with neurological decline.
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31
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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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32
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Carrillo-Jimenez A, Puigdellívol M, Vilalta A, Venero JL, Brown GC, StGeorge-Hyslop P, Burguillos MA. Effective Knockdown of Gene Expression in Primary Microglia With siRNA and Magnetic Nanoparticles Without Cell Death or Inflammation. Front Cell Neurosci 2018; 12:313. [PMID: 30297984 PMCID: PMC6161539 DOI: 10.3389/fncel.2018.00313] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/29/2018] [Indexed: 01/23/2023] Open
Abstract
Microglia, the resident immune cells of the brain, have multiple functions in physiological and pathological conditions, including Alzheimer’s disease (AD). The use of primary microglial cell cultures has proved to be a valuable tool to study microglial biology under various conditions. However, more advanced transfection methodologies for primary cultured microglia are still needed, as current methodologies provide low transfection efficiency and induce cell death and/or inflammatory activation of the microglia. Here, we describe an easy, and effective method based on the Glial-Mag method (OZ Biosciences) using magnetic nanoparticles and a magnet to successfully transfect primary microglia cells with different small interfering RNAs (siRNAs). This method does not require specialist facilities or specific training and does not induce cell toxicity or inflammatory activation. We demonstrate that this protocol successfully decreases the expression of two key genes associated with AD, the triggering receptor expressed in myeloid cells 2 (TREM2) and CD33, in primary microglia cell cultures.
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Affiliation(s)
- Alejandro Carrillo-Jimenez
- Departamento de 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
| | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Anna Vilalta
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jose Luis Venero
- Departamento de 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
| | - Guy Charles Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Peter StGeorge-Hyslop
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Miguel Angel Burguillos
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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33
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Carbajosa G, Malki K, Lawless N, Wang H, Ryder JW, Wozniak E, Wood K, Mein CA, Dobson RJB, Collier DA, O'Neill MJ, Hodges AK, Newhouse SJ. Loss of Trem2 in microglia leads to widespread disruption of cell coexpression networks in mouse brain. Neurobiol Aging 2018; 69:151-166. [PMID: 29906661 PMCID: PMC6075941 DOI: 10.1016/j.neurobiolaging.2018.04.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/26/2018] [Accepted: 04/28/2018] [Indexed: 12/19/2022]
Abstract
Rare heterozygous coding variants in the triggering receptor expressed in myeloid cells 2 (TREM2) gene, conferring increased risk of developing late-onset Alzheimer's disease, have been identified. We examined the transcriptional consequences of the loss of Trem2 in mouse brain to better understand its role in disease using differential expression and coexpression network analysis of Trem2 knockout and wild-type mice. We generated RNA-Seq data from cortex and hippocampus sampled at 4 and 8 months. Using brain cell-type markers and ontology enrichment, we found subnetworks with cell type and/or functional identity. We primarily discovered changes in an endothelial gene-enriched subnetwork at 4 months, including a shift toward a more central role for the amyloid precursor protein gene, coupled with widespread disruption of other cell-type subnetworks, including a subnetwork with neuronal identity. We reveal an unexpected potential role of Trem2 in the homeostasis of endothelial cells that goes beyond its known functions as a microglial receptor and signaling hub, suggesting an underlying link between immune response and vascular disease in dementia.
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Affiliation(s)
- Guillermo Carbajosa
- Department of Biostatistics and Health Informatics, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.
| | | | | | - Hong Wang
- Eli Lilly and Company, Indianapolis, IN, USA
| | | | - Eva Wozniak
- Barts and the London Genome Centre, John Vane Science Centre, Barts and the London School of Medicine and Dentistry, London, UK
| | - Kristie Wood
- Barts and the London Genome Centre, John Vane Science Centre, Barts and the London School of Medicine and Dentistry, London, UK
| | - Charles A Mein
- Barts and the London Genome Centre, John Vane Science Centre, Barts and the London School of Medicine and Dentistry, London, UK
| | - Richard J B Dobson
- Department of Biostatistics and Health Informatics, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK; NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, London, UK; Farr Institute of Health Informatics Research, UCL Institute of Health Informatics, University College London, London, UK
| | | | | | - Angela K Hodges
- Maurice Wohl Clinical Neuroscience Institute James Black Centre Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Stephen J Newhouse
- Department of Biostatistics and Health Informatics, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK; NIHR Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, London, UK; Farr Institute of Health Informatics Research, UCL Institute of Health Informatics, University College London, London, UK
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34
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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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35
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Brownjohn PW, Smith J, Solanki R, Lohmann E, Houlden H, Hardy J, Dietmann S, Livesey FJ. Functional Studies of Missense TREM2 Mutations in Human Stem Cell-Derived Microglia. Stem Cell Reports 2018; 10:1294-1307. [PMID: 29606617 PMCID: PMC5998752 DOI: 10.1016/j.stemcr.2018.03.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 01/02/2023] Open
Abstract
The derivation of microglia from human stem cells provides systems for understanding microglial biology and enables functional studies of disease-causing mutations. We describe a robust method for the derivation of human microglia from stem cells, which are phenotypically and functionally comparable with primary microglia. We used stem cell-derived microglia to study the consequences of missense mutations in the microglial-expressed protein triggering receptor expressed on myeloid cells 2 (TREM2), which are causal for frontotemporal dementia-like syndrome and Nasu-Hakola disease. We find that mutant TREM2 accumulates in its immature form, does not undergo typical proteolysis, and is not trafficked to the plasma membrane. However, in the absence of plasma membrane TREM2, microglia differentiate normally, respond to stimulation with lipopolysaccharide, and are phagocytically competent. These data indicate that dementia-associated TREM2 mutations have subtle effects on microglia biology, consistent with the adult onset of disease in individuals with these mutations.
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Affiliation(s)
- Philip W Brownjohn
- The Gurdon Institute, ARUK Stem Cell Research Centre and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK
| | - James Smith
- The Gurdon Institute, ARUK Stem Cell Research Centre and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK
| | - Ravi Solanki
- The Gurdon Institute, ARUK Stem Cell Research Centre and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK
| | - Ebba Lohmann
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen 72076, Germany; DZNE, German Center for Neurodegenerative Diseases, Tübingen 72076, Germany
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Sabine Dietmann
- Wellcome Trust Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Frederick J Livesey
- The Gurdon Institute, ARUK Stem Cell Research Centre and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, UK.
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36
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Cheng Q, Danao J, Talreja S, Wen P, Yin J, Sun N, Li CM, Chui D, Tran D, Koirala S, Chen H, Foltz IN, Wang S, Sambashivan S. TREM2-activating antibodies abrogate the negative pleiotropic effects of the Alzheimer's disease variant Trem2R47H on murine myeloid cell function. J Biol Chem 2018; 293:12620-12633. [PMID: 29599291 DOI: 10.1074/jbc.ra118.001848] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/23/2018] [Indexed: 12/28/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is an orphan immune receptor expressed on cells of myeloid lineage such as macrophages and microglia. The rare variant R47H TREM2 is associated with an increased risk for Alzheimer's disease, supporting the hypothesis that TREM2 loss of function may exacerbate disease progression. However, a complete knockout of the TREM2 gene in different genetic models of neurodegenerative diseases has been reported to result in both protective and deleterious effects on disease-related end points and myeloid cell function. Here, we describe a Trem2R47H transgenic mouse model and report that even in the absence of additional genetic perturbations, this variant clearly confers a loss of function on myeloid cells. The Trem2R47H variant-containing myeloid cells exhibited subtle defects in survival and migration and displayed an unexpected dysregulation of cytokine responses in a lipopolysaccharide challenge environment. These subtle phenotypic defects with a gradation in severity across genotypes were confirmed in whole-genome RNA-Seq analyses of WT, Trem2-/-, and Trem2R47H myeloid cells under challenge conditions. Of note, TREM2-activating antibodies that boost proximal signaling abrogated survival defects conferred by the variant and also modulated migration and cytokine responses in an antibody-, ligand-, and challenge-dependent manner. In some instances, these antibodies also boosted WT myeloid cell function. Our studies provide a first glimpse into the boost in myeloid cell function that can be achieved by pharmacological modulation of TREM2 activity that can potentially be ameliorative in neurodegenerative diseases such as Alzheimer's disease.
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Affiliation(s)
- Qingwen Cheng
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Jean Danao
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Santosh Talreja
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Paul Wen
- the Department of Discovery Research, Amgen, Thousand Oaks, California 91320, and
| | - Jun Yin
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Ning Sun
- the Department of Discovery Research, Amgen, Thousand Oaks, California 91320, and
| | - Chi-Ming Li
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Danny Chui
- the Department of Discovery Research, Amgen, Burnaby, British Columbia V5A IV7, Canada
| | - David Tran
- the Department of Discovery Research, Amgen, Thousand Oaks, California 91320, and
| | - Samir Koirala
- the Department of Discovery Research, Amgen, Thousand Oaks, California 91320, and
| | - Hang Chen
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Ian N Foltz
- the Department of Discovery Research, Amgen, Burnaby, British Columbia V5A IV7, Canada
| | - Songli Wang
- From the Department of Discovery Research, Amgen, San Francisco, California 94080
| | - Shilpa Sambashivan
- From the Department of Discovery Research, Amgen, San Francisco, California 94080,
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37
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Jankowsky JL, Zheng H. Practical considerations for choosing a mouse model of Alzheimer's disease. Mol Neurodegener 2017; 12:89. [PMID: 29273078 PMCID: PMC5741956 DOI: 10.1186/s13024-017-0231-7] [Citation(s) in RCA: 272] [Impact Index Per Article: 38.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/07/2017] [Indexed: 01/06/2023] Open
Abstract
Alzheimer’s disease (AD) is behaviorally identified by progressive memory impairment and pathologically characterized by the triad of β-amyloid plaques, neurofibrillary tangles, and neurodegeneration. Genetic mutations and risk factors have been identified that are either causal or modify the disease progression. These genetic and pathological features serve as basis for the creation and validation of mouse models of AD. Efforts made in the past quarter-century have produced over 100 genetically engineered mouse lines that recapitulate some aspects of AD clinicopathology. These models have been valuable resources for understanding genetic interactions that contribute to disease and cellular reactions that are engaged in response. Here we focus on mouse models that have been widely used stalwarts of the field or that are recently developed bellwethers of the future. Rather than providing a summary of each model, we endeavor to compare and contrast the genetic approaches employed and to discuss their respective advantages and limitations. We offer a critical account of the variables which may contribute to inconsistent findings and the factors that should be considered when choosing a model and interpreting the results. We hope to present an insightful review of current AD mouse models and to provide a practical guide for selecting models best matched to the experimental question at hand.
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Affiliation(s)
- Joanna L Jankowsky
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Neurosurgery, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Hui Zheng
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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