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Fabiano M, Oikawa N, Kerksiek A, Furukawa JI, Yagi H, Kato K, Schweizer U, Annaert W, Kang J, Shen J, Lütjohann D, Walter J. Presenilin Deficiency Results in Cellular Cholesterol Accumulation by Impairment of Protein Glycosylation and NPC1 Function. Int J Mol Sci 2024; 25:5417. [PMID: 38791456 PMCID: PMC11121565 DOI: 10.3390/ijms25105417] [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: 04/11/2024] [Revised: 05/12/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
Presenilin proteins (PS1 and PS2) represent the catalytic subunit of γ-secretase and play a critical role in the generation of the amyloid β (Aβ) peptide and the pathogenesis of Alzheimer disease (AD). However, PS proteins also exert multiple functions beyond Aβ generation. In this study, we examine the individual roles of PS1 and PS2 in cellular cholesterol metabolism. Deletion of PS1 or PS2 in mouse models led to cholesterol accumulation in cerebral neurons. Cholesterol accumulation was also observed in the lysosomes of embryonic fibroblasts from Psen1-knockout (PS1-KO) and Psen2-KO (PS2-KO) mice and was associated with decreased expression of the Niemann-Pick type C1 (NPC1) protein involved in intracellular cholesterol transport in late endosomal/lysosomal compartments. Mass spectrometry and complementary biochemical analyses also revealed abnormal N-glycosylation of NPC1 and several other membrane proteins in PS1-KO and PS2-KO cells. Interestingly, pharmacological inhibition of N-glycosylation resulted in intracellular cholesterol accumulation prominently in lysosomes and decreased NPC1, thereby resembling the changes in PS1-KO and PS2-KO cells. In turn, treatment of PS1-KO and PS2-KO mouse embryonic fibroblasts (MEFs) with the chaperone inducer arimoclomol partially normalized NPC1 expression and rescued lysosomal cholesterol accumulation. Additionally, the intracellular cholesterol accumulation in PS1-KO and PS2-KO MEFs was prevented by overexpression of NPC1. Collectively, these data indicate that a loss of PS function results in impaired protein N-glycosylation, which eventually causes decreased expression of NPC1 and intracellular cholesterol accumulation. This mechanism could contribute to the neurodegeneration observed in PS KO mice and potentially to the pathogenesis of AD.
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Affiliation(s)
- Marietta Fabiano
- Department of Neurology, Universitätsklinikum Bonn, 53127 Bonn, Germany
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Naoto Oikawa
- Department of Neurology, Universitätsklinikum Bonn, 53127 Bonn, Germany
| | - Anja Kerksiek
- Institute of Clinical Chemistry and Clinical Pharmacology, Universitätsklinikum Bonn, 53127 Bonn, Germany
| | - Jun-ichi Furukawa
- Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
- Division of Glyco-Systems Biology, Institute for Glyco-Core Research, Tokai National Higher Education and Research System, Nagoya 466-8550, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki 444-8787, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585, Japan
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Universitätsklinikum Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53115 Bonn, Germany
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Jongkyun Kang
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jie Shen
- Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA
| | - Dieter Lütjohann
- Institute of Clinical Chemistry and Clinical Pharmacology, Universitätsklinikum Bonn, 53127 Bonn, Germany
| | - Jochen Walter
- Department of Neurology, Universitätsklinikum Bonn, 53127 Bonn, Germany
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2
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Farfara D, Sooliman M, Avrahami L, Royal TG, Amram S, Rozenstein-Tsalkovich L, Trudler D, Blanga-Kanfi S, Eldar-Finkelman H, Pahnke J, Rosenmann H, Frenkel D. Physiological expression of mutated TAU impaired astrocyte activity and exacerbates β-amyloid pathology in 5xFAD mice. J Neuroinflammation 2023; 20:174. [PMID: 37496076 PMCID: PMC10369740 DOI: 10.1186/s12974-023-02823-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 06/04/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is the leading cause of dementia in the world. The pathology of AD is affiliated with the elevation of both tau (τ) and β-amyloid (Aβ) pathologies. Yet, the direct link between natural τ expression on glia cell activity and Aβ remains unclear. While experiments in mouse models suggest that an increase in Aβ exacerbates τ pathology when expressed under a neuronal promoter, brain pathology from AD patients suggests an appearance of τ pathology in regions without Aβ. METHODS Here, we aimed to assess the link between τ and Aβ using a new mouse model that was generated by crossing a mouse model that expresses two human mutations of the human MAPT under a mouse Tau natural promoter with 5xFAD mice that express human mutated APP and PS1 in neurons. RESULTS The new mouse model, called 5xFAD TAU, shows accelerated cognitive impairment at 2 months of age, increased number of Aβ depositions at 4 months and neuritic plaques at 6 months of age. An expression of human mutated TAU in astrocytes leads to a dystrophic appearance and reduces their ability to engulf Aβ, which leads to an increased brain Aβ load. Astrocytes expressing mutated human TAU showed an impairment in the expression of vascular endothelial growth factor (VEGF) that has previously been suggested to play an important role in supporting neurons. CONCLUSIONS Our results suggest the role of τ in exacerbating Aβ pathology in addition to pointing out the potential role of astrocytes in disease progression. Further research of the crosstalk between τ and Aβ in astrocytes may increase our understanding of the role glia cells have in the pathology of AD with the aim of identifying novel therapeutic interventions to an otherwise currently incurable disease.
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Affiliation(s)
- Dorit Farfara
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Meital Sooliman
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Limor Avrahami
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Tabitha Grace Royal
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Shoshik Amram
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Lea Rozenstein-Tsalkovich
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Dorit Trudler
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Shani Blanga-Kanfi
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Hagit Eldar-Finkelman
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Jens Pahnke
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
- Section of Neuropathology, Translational Neurodegeneration Research and Neuropathology Lab, Department of Pathology, University of Oslo (UiO) and Oslo University Hospital (OUS), Oslo, Norway.
- Drug Development and Chemical Biology, Lübeck Institute of Dermatology (LIED), University Medical Center Schleswig Holstein (UKSH), LIED, Lübeck, Germany.
- Department of Pharmacology, Faculty of Medicine, University of Latvia, Riga, Latvia.
| | - Hanna Rosenmann
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
| | - Dan Frenkel
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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3
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Miao J, Ma H, Yang Y, Liao Y, Lin C, Zheng J, Yu M, Lan J. Microglia in Alzheimer's disease: pathogenesis, mechanisms, and therapeutic potentials. Front Aging Neurosci 2023; 15:1201982. [PMID: 37396657 PMCID: PMC10309009 DOI: 10.3389/fnagi.2023.1201982] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by protein aggregation in the brain. Recent studies have revealed the critical role of microglia in AD pathogenesis. This review provides a comprehensive summary of the current understanding of microglial involvement in AD, focusing on genetic determinants, phenotypic state, phagocytic capacity, neuroinflammatory response, and impact on synaptic plasticity and neuronal regulation. Furthermore, recent developments in drug discovery targeting microglia in AD are reviewed, highlighting potential avenues for therapeutic intervention. This review emphasizes the essential role of microglia in AD and provides insights into potential treatments.
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Affiliation(s)
- Jifei Miao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Haixia Ma
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yang Yang
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Yuanpin Liao
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Cui Lin
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Juanxia Zheng
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Muli Yu
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Jiao Lan
- Shenzhen Bao’an Traditional Chinese Medicine Hospital, Shenzhen, China
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4
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Hiraga SI, Itokazu T, Nishibe M, Yamashita T. Neuroplasticity related to chronic pain and its modulation by microglia. Inflamm Regen 2022; 42:15. [PMID: 35501933 PMCID: PMC9063368 DOI: 10.1186/s41232-022-00199-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/19/2022] [Indexed: 01/03/2023] Open
Abstract
Neuropathic pain is often chronic and can persist after overt tissue damage heals, suggesting that its underlying mechanism involves the alteration of neuronal function. Such an alteration can be a direct consequence of nerve damage or a result of neuroplasticity secondary to the damage to tissues or to neurons. Recent studies have shown that neuroplasticity is linked to causing neuropathic pain in response to nerve damage, which may occur adjacent to or remotely from the site of injury. Furthermore, studies have revealed that neuroplasticity relevant to chronic pain is modulated by microglia, resident immune cells of the central nervous system (CNS). Microglia may directly contribute to synaptic remodeling and altering pain circuits, or indirectly contribute to neuroplasticity through property changes, including the secretion of growth factors. We herein highlight the mechanisms underlying neuroplasticity that occur in the somatosensory circuit of the spinal dorsal horn, thalamus, and cortex associated with chronic pain following injury to the peripheral nervous system (PNS) or CNS. We also discuss the dynamic functions of microglia in shaping neuroplasticity related to chronic pain. We suggest further understanding of post-injury ectopic plasticity in the somatosensory circuits may shed light on the differential mechanisms underlying nociceptive, neuropathic, and nociplastic-type pain. While one of the prominent roles played by microglia appears to be the modulation of post-injury neuroplasticity. Therefore, future molecular- or genetics-based studies that address microglia-mediated post-injury neuroplasticity may contribute to the development of novel therapies for chronic pain.
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Affiliation(s)
- Shin-Ichiro Hiraga
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Takahide Itokazu
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
| | - Mariko Nishibe
- Center for Strategic Innovative Dentistry, Graduate School of Dentistry, Osaka University, Suita, Osaka, Japan
| | - Toshihide Yamashita
- Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan. .,WPI Immunology Frontier Research Center, Osaka, Japan. .,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
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5
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Tajbakhsh A, Read M, Barreto GE, Ávila-Rodriguez M, Gheibi-Hayat SM, Sahebkar A. Apoptotic neurons and amyloid-beta clearance by phagocytosis in Alzheimer's disease: Pathological mechanisms and therapeutic outlooks. Eur J Pharmacol 2021; 895:173873. [PMID: 33460611 DOI: 10.1016/j.ejphar.2021.173873] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 12/13/2022]
Abstract
Neuronal survival and axonal renewal following central nervous system damage and in neurodegenerative illnesses, such as Alzheimer's disease (AD), can be enhanced by fast clearance of neuronal apoptotic debris, as well as the removal of amyloid beta (Aβ) by phagocytic cells through the process of efferocytosis. This process quickly inhibits the release of proinflammatory and antigenic autoimmune constituents, enhancing the formation of a microenvironment vital for neuronal survival and axonal regeneration. Therefore, the detrimental features associated with microglial phagocytosis uncoupling, such as the accumulation of apoptotic cells, inflammation and phagoptosis, could exacerbate the pathology in brain disease. Some mechanisms of efferocytosis could be targeted by several promising agents, such as curcumin, URMC-099 and Y-P30, which have emerged as potential treatments for AD. This review aims to investigate and update the current research regarding the signaling molecules and pathways involved in efferocytosis and how these could be targeted as a potential therapy in AD.
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Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences & Technologies, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Morgayn Read
- Department of Pharmacology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick, Ireland; Health Research Institute, University of Limerick, Limerick, Ireland
| | | | - Seyed Mohammad Gheibi-Hayat
- Department of Medical Biotechnology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Polish Mother's Memorial Hospital Research Institute (PMMHRI), Lodz, Poland.
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6
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Bettcher BM, Tansey MG, Dorothée G, Heneka MT. Peripheral and central immune system crosstalk in Alzheimer disease - a research prospectus. Nat Rev Neurol 2021; 17:689-701. [PMID: 34522039 PMCID: PMC8439173 DOI: 10.1038/s41582-021-00549-x] [Citation(s) in RCA: 161] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2021] [Indexed: 02/08/2023]
Abstract
Dysregulation of the immune system is a cardinal feature of Alzheimer disease (AD), and a considerable body of evidence indicates pathological alterations in central and peripheral immune responses that change over time. Considering AD as a systemic immune process raises important questions about how communication between the peripheral and central compartments occurs and whether this crosstalk represents a therapeutic target. We established a whitepaper workgroup to delineate the current status of the field and to outline a research prospectus for advancing our understanding of peripheral-central immune crosstalk in AD. To guide the prospectus, we begin with an overview of seminal clinical observations that suggest a role for peripheral immune dysregulation and peripheral-central immune communication in AD, followed by formative animal data that provide insights into possible mechanisms for these clinical findings. We then present a roadmap that defines important next steps needed to overcome conceptual and methodological challenges, opportunities for future interdisciplinary research, and suggestions for translating promising mechanistic studies into therapeutic interventions.
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Affiliation(s)
- Brianne M. Bettcher
- grid.430503.10000 0001 0703 675XBehavioral Neurology Section, Department of Neurology, University of Colorado Alzheimer’s and Cognition Center, University of Colorado Anschutz Medical Campus, Aurora, CO USA
| | - Malú G. Tansey
- grid.15276.370000 0004 1936 8091Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida College of Medicine, Gainesville, FL USA
| | - Guillaume Dorothée
- grid.412370.30000 0004 1937 1100Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, Team “Immune System and Neuroinflammation”, Hôpital Saint-Antoine, Paris, France
| | - Michael T. Heneka
- grid.15090.3d0000 0000 8786 803XDepartment of Neurodegenerative Diseases & Geropsychiatry/Neurology, University of Bonn Medical Center, Bonn, Germany ,grid.168645.80000 0001 0742 0364Department of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA USA
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7
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Ibach M, Mathews M, Linnartz-Gerlach B, Theil S, Kumar S, Feederle R, Brüstle O, Neumann H, Walter J. A reporter cell system for the triggering receptor expressed on myeloid cells 2 reveals differential effects of disease-associated variants on receptor signaling and activation by antibodies against the stalk region. Glia 2020; 69:1126-1139. [PMID: 33314333 DOI: 10.1002/glia.23953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 12/31/2022]
Abstract
The triggering receptor expressed on myeloid cells 2 (TREM2) is an immune receptor expressed on myeloid-derived cell types. The extracellular immunoglobulin-like domain of TREM2 binds anionic ligands including Apolipoprotein E and Amyloid-β. The transmembrane domain interacts with its adaptor protein DAP12/TYROBP that is responsible for propagation of downstream signaling upon ligand interaction. Several sequence variants of TREM2 have been linked to different neurodegenerative diseases including Alzheimer's disease. Here, we generated HEK 293 Flp-In cell lines stably expressing human TREM2 and DAP12 using a bicistronic construct with a T2A linker sequence allowing initial expression of both proteins in stoichiometric amounts. Cell biological and biochemical analyses revealed transport of TREM2 to the cell surface, and canonical sequential proteolytic processing and shedding of TREM2 (sTREM2). The functionality of this cell system was demonstrated by detection of phosphorylated spleen tyrosine kinase (SYK) upon stimulation of TREM2 with the anionic membrane lipid phosphatidylserine or anti-TREM2 antibodies. Using this cell model, we demonstrated impaired signaling of disease associated TREM2 variants. We also identified a monoclonal antibody against the stalk region of TREM2 with agonistic activity. Activation of TREM2-DAP12 signaling with the monoclonal antibody and the partial loss of function of disease associated variants were recapitulated in induced pluripotent stem cell derived microglia. Thus, this reporter cell model represents a suitable experimental system to investigate signaling of TREM2 variants, and for the identification of ligands and compounds that modulate TREM2-DAP12 signaling. MAIN POINTS: Disease associated variants impair the signaling activity of TREM2 by distinct mechanisms. Targeting the stalk region of TREM2 with bivalent antibodies activates TREM2 signaling.
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Affiliation(s)
- Melanie Ibach
- Department of Neurology, University of Bonn, Bonn, Germany
| | | | - Bettina Linnartz-Gerlach
- Neural Regeneration, Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Sandra Theil
- Department of Neurology, University of Bonn, Bonn, Germany
| | - Sathish Kumar
- Department of Neurology, University of Bonn, Bonn, Germany
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Core Facility Monoclonal Antibodies, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Oliver Brüstle
- Life and Brain GmbH, Bonn, Germany.,Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty & University Hospital Bonn, Bonn, Germany
| | - Jochen Walter
- Department of Neurology, University of Bonn, Bonn, Germany
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8
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Bonfili L, Cecarini V, Gogoi O, Gong C, Cuccioloni M, Angeletti M, Rossi G, Eleuteri AM. Microbiota modulation as preventative and therapeutic approach in Alzheimer's disease. FEBS J 2020; 288:2836-2855. [PMID: 32969566 DOI: 10.1111/febs.15571] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/27/2020] [Accepted: 09/17/2020] [Indexed: 12/23/2022]
Abstract
The gut microbiota coevolves with its host, and numerous factors like diet, lifestyle, drug intake and geographical location continuously modify its composition, deeply influencing host health. Recent studies demonstrated that gut dysbiosis can alter normal brain function through the so-called gut-brain axis, a bidirectional communication network between the central nervous system and the gastrointestinal tract, thus playing a key role in the pathogenesis of neurodegenerative disorders, such as Alzheimer's disease (AD). In this perspective, in the constant search for novel treatments in AD, the rational modulation of gut microbiota composition could represent a promising approach to prevent or delay AD onset or to counteract its progression. Preclinical and human studies on microbiota modulation through oral bacteriotherapy and faecal transplantation showed anti-inflammatory and antioxidant effects, upregulation of plasma concentration of neuroprotective hormones, restoration of impaired proteolytic pathways, amelioration of energy homeostasis with consequent decrease of AD molecular hallmarks and improvement of behavioural and cognitive performances. In this review, we dissect the role of gut microbiota in AD and highlight recent advances in the development of new multitarget strategies for microbiota modulation to be used as possible preventative and therapeutic approaches in AD.
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Affiliation(s)
- Laura Bonfili
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Olee Gogoi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Chunmei Gong
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | | | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Giacomo Rossi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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9
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Fung S, Smith CL, Prater KE, Case A, Green K, Osnis L, Winston C, Kinoshita Y, Sopher B, Morrison RS, Garden GA, Jayadev S. Early-Onset Familial Alzheimer Disease Variant PSEN2 N141I Heterozygosity is Associated with Altered Microglia Phenotype. J Alzheimers Dis 2020; 77:675-688. [PMID: 32741831 PMCID: PMC7592656 DOI: 10.3233/jad-200492] [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] [Indexed: 02/02/2023]
Abstract
BACKGROUND Early-onset familial Alzheimer disease (EOFAD) is caused by heterozygous variants in the presenilin 1 (PSEN1), presenilin 2 (PSEN2), and APP genes. Decades after their discovery, the mechanisms by which these genes cause Alzheimer's disease (AD) or promote AD progression are not fully understood. While it is established that presenilin (PS) enzymatic activity produces amyloid-β (Aβ), PSs also regulate numerous other cellular functions, some of which intersect with known pathogenic drivers of neurodegeneration. Accumulating evidence suggests that microglia, resident innate immune cells in the central nervous system, play a key role in AD neurodegeneration. OBJECTIVE Previous work has identified a regulatory role for PS2 in microglia. We hypothesized that PSEN2 variants lead to dysregulated microglia, which could further contribute to disease acceleration. To mimic the genotype of EOFAD patients, we created a transgenic mouse expressing PSEN2 N141I on a mouse background expressing one wildtype PS2 and two PS1 alleles. RESULTS Microglial expression of PSEN2 N141I resulted in impaired γ-secretase activity as well as exaggerated inflammatory cytokine release, NFκB activity, and Aβ internalization. In vivo, PS2 N141I mice showed enhanced IL-6 and TREM2 expression in brain as well as reduced branch number and length, an indication of "activated" morphology, in the absence of inflammatory stimuli. LPS intraperitoneal injection resulted in higher inflammatory gene expression in PS2 N141I mouse brain relative to controls. CONCLUSION Our findings demonstrate that PSEN2 N141I heterozygosity is associated with disrupted innate immune homeostasis, suggesting EOFAD variants may promote disease progression through non-neuronal cells beyond canonical dysregulated Aβ production.
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Affiliation(s)
- Susan Fung
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Carole L. Smith
- Department of Neurology, University of Washington, Seattle, WA, USA
| | | | - Amanda Case
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Kevin Green
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Leah Osnis
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Chloe Winston
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Yoshito Kinoshita
- Department of Neurosurgery, University of Washington, Seattle, WA, USA
| | - Bryce Sopher
- Department of Neurology, University of Washington, Seattle, WA, USA
| | | | - Gwenn A. Garden
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
| | - Suman Jayadev
- Department of Neurology, University of Washington, Seattle, WA, USA,Dr. Suman Jayadev, Department of Neurology, Box 356465, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA. Tel.: +1 206 221 2930;
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10
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Gupta SP, Patil VM. Recent Studies on Design and Development of Drugs Against Alzheimer's Disease (AD) Based on Inhibition of BACE-1 and Other AD-causative Agents. Curr Top Med Chem 2020; 20:1195-1213. [PMID: 32297584 DOI: 10.2174/1568026620666200416091623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is one of the neurodegenerative diseases and has been hypothesized to be a protein misfolding disease. In the generation of AD, β-secretase, γ-secretase, and tau protein play an important role. A literature search reflects ever increasing interest in the design and development of anti-AD drugs targeting β-secretase, γ-secretase, and tau protein. OBJECTIVE The objective is to explore the structural aspects and role of β-secretase, γ-secretase, and tau protein in AD and the efforts made to exploit them for the design of effective anti-AD drugs. METHODS The manuscript covers the recent studies on design and development of anti-AD drugs exploiting amyloid and cholinergic hypotheses. RESULTS Based on amyloid and cholinergic hypotheses, effective anti-AD drugs have been searched out in which non-peptidic BACE1 inhibitors have been most prominent. CONCLUSION Further exploitation of the structural aspects and the inhibition mechanism for β-secretase, γ-secretase, and tau protein and the use of cholinergic hypothesis may lead still more potent anti-AD drugs.
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Affiliation(s)
- Satya P Gupta
- Department of Pharmaceutical Technology, Meerut Institute of Engineering and Technology, Meerut-250005, India
| | - Vaishali M Patil
- Computer Aided Drug Design Lab, Department of Pharmaceutical Chemistry, KIET School of Pharmacy, KIET Group of Institutions, Delhi-NCR, Ghaziabad-201206, Uttar Pradesh, India
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11
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Trudler D, Levy‐Barazany H, Nash Y, Samuel L, Sharon R, Frenkel D. Alpha synuclein deficiency increases CD4
+
T‐cells pro‐inflammatory profile in a Nurr1‐dependent manner. J Neurochem 2019; 152:61-71. [DOI: 10.1111/jnc.14871] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/05/2019] [Accepted: 09/10/2019] [Indexed: 01/25/2023]
Affiliation(s)
- Dorit Trudler
- Department of Neurobiology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
- Sagol School of Neuroscience Tel Aviv University Tel Aviv Israel
| | - Hilit Levy‐Barazany
- Department of Neurobiology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Yuval Nash
- Department of Neurobiology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
- Sagol School of Neuroscience Tel Aviv University Tel Aviv Israel
| | - Liron Samuel
- Department of Neurobiology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Ronit Sharon
- Faculty of Medicine Biochemistry and Molecular Biology IMRIC The Hebrew University Jerusalem Jerusalem Israel
| | - Dan Frenkel
- Department of Neurobiology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
- Sagol School of Neuroscience Tel Aviv University Tel Aviv Israel
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12
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Chen Z, Zhong D, Li G. The role of microglia in viral encephalitis: a review. J Neuroinflammation 2019; 16:76. [PMID: 30967139 PMCID: PMC6454758 DOI: 10.1186/s12974-019-1443-2] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/24/2019] [Indexed: 12/16/2022] Open
Abstract
Viral encephalitis is still very prominent around the world, and traditional antiviral therapies still have shortcomings. Some patients cannot get effective relief or suffer from serious sequelae. At present, people are studying the role of the innate immune system in viral encephalitis. Microglia, as resident cells of the central nervous system (CNS), can respond quickly to various CNS injuries including trauma, ischemia, and infection and maintain the homeostasis of CNS, but this response is not always good; sometimes, it will exacerbate damage. Studies have shown that microglia also act as a double-edged sword during viral encephalitis. On the one hand, microglia can sense ATP signals through the purinergic receptor P2Y12 and are recruited around infected neurons to exert phagocytic activity. Microglia can exert a direct antiviral effect by producing type 1 interferon (IFN-1) to induce IFN-stimulated gene (ISG) expression of themselves or indirect antiviral effects by IFN-1 acting on other cells to activate corresponding signaling pathways. In addition, microglia can also exert an antiviral effect by inducing autophagy or secreting cytokines. On the other hand, microglia mediate presynaptic membrane damage in the hippocampus through complement, resulting in long-term memory impairment and cognitive dysfunction in patients with encephalitis. Microglia mediate fetal congenital malformations caused by Zika virus (ZIKV) infection. The gene expression profile of microglia in HIV encephalitis changes, and they tend to be a pro-inflammatory type. Microglia inhibited neuronal autophagy and aggravated the damage of CNS in HIV encephalitis; E3 ubiquitin ligase Pellino (pelia) expressed by microglia promotes the replication of virus in neurons. The interaction between amyloid-β peptide (Aβ) produced by neurons and activated microglia during viral infection is uncertain. Although neurons can mediate antiviral effects by activating receptor-interacting protein kinases 3 (RIPK3) in a death-independent pathway, the RIPK3 pathway of microglia is unknown. Different brain regions have different susceptibility to viruses, and the gene expression of microglia in different brain regions is specific. The relationship between the two needs to be further confirmed. How to properly regulate the function of microglia and make it exert more anti-inflammatory effects is our next research direction.
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Affiliation(s)
- Zhuangzhuang Chen
- Department of Neurology, The First Affiliated Hospital, Harbin Medical University, 23 You Zheng Street, Harbin, 150001, Heilong Jiang Province, People's Republic of China.
| | - Di Zhong
- Department of Neurology, The First Affiliated Hospital, Harbin Medical University, 23 You Zheng Street, Harbin, 150001, Heilong Jiang Province, People's Republic of China
| | - Guozhong Li
- Department of Neurology, The First Affiliated Hospital, Harbin Medical University, 23 You Zheng Street, Harbin, 150001, Heilong Jiang Province, People's Republic of China
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13
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Farfara D, Feierman E, Richards A, Revenko AS, MacLeod RA, Norris EH, Strickland S. Knockdown of circulating C1 inhibitor induces neurovascular impairment, glial cell activation, neuroinflammation, and behavioral deficits. Glia 2019; 67:1359-1373. [PMID: 30882931 DOI: 10.1002/glia.23611] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 02/11/2019] [Accepted: 02/19/2019] [Indexed: 12/20/2022]
Abstract
The cross-talk between blood proteins, immune cells, and brain function involves complex mechanisms. Plasma protein C1 inhibitor (C1INH) is an inhibitor of vascular inflammation that is induced by activation of the kallikrein-kinin system (KKS) and the complement system. Knockout of C1INH was previously correlated with peripheral vascular permeability via the bradykinin pathway, yet there was no evidence of its correlation with blood-brain barrier (BBB) integrity and brain function. In order to understand the effect of plasma C1INH on brain pathology via the vascular system, we knocked down circulating C1INH in wild-type (WT) mice using an antisense oligonucleotide (ASO), without affecting C1INH expression in peripheral immune cells or the brain, and examined brain pathology. Long-term elimination of endogenous C1INH in the plasma induced the activation of the KKS and peritoneal macrophages but did not activate the complement system. Bradykinin pathway proteins were elevated in the periphery and the brain, resulting in hypotension. BBB permeability, extravasation of plasma proteins into the brain parenchyma, activation of glial cells, and elevation of pro-inflammatory response mediators were detected. Furthermore, infiltrating innate immune cells were observed entering the brain through the lateral ventricle walls and the neurovascular unit. Mice showed normal locomotion function, yet cognition was impaired and depressive-like behavior was evident. In conclusion, our results highlight the important role of regulated plasma C1INH as it acts as a gatekeeper to the brain via the neurovascular system. Thus, manipulation of C1INH in neurovascular disorders might be therapeutically beneficial.
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Affiliation(s)
- Dorit Farfara
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, New York
| | - Emily Feierman
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, New York
| | - Allison Richards
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, New York
| | - Alexey S Revenko
- Department of Antisense Drug Discovery, IONIS Pharmaceuticals Inc., Carlsbad, California
| | - Robert A MacLeod
- Department of Antisense Drug Discovery, IONIS Pharmaceuticals Inc., Carlsbad, California
| | - Erin H Norris
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, New York
| | - Sidney Strickland
- Patricia and John Rosenwald Laboratory of Neurobiology and Genetics, The Rockefeller University, New York, New York
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14
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Oikawa N, Walter J. Presenilins and γ-Secretase in Membrane Proteostasis. Cells 2019; 8:cells8030209. [PMID: 30823664 PMCID: PMC6468700 DOI: 10.3390/cells8030209] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/20/2022] Open
Abstract
The presenilin (PS) proteins exert a crucial role in the pathogenesis of Alzheimer disease (AD) by mediating the intramembranous cleavage of amyloid precursor protein (APP) and the generation of amyloid β-protein (Aβ). The two homologous proteins PS1 and PS2 represent the catalytic subunits of distinct γ-secretase complexes that mediate a variety of cellular processes, including membrane protein metabolism, signal transduction, and cell differentiation. While the intramembrane cleavage of select proteins by γ-secretase is critical in the regulation of intracellular signaling pathways, the plethora of identified protein substrates could also indicate an important role of these enzyme complexes in membrane protein homeostasis. In line with this notion, PS proteins and/or γ-secretase has also been implicated in autophagy, a fundamental process for the maintenance of cellular functions and homeostasis. Dysfunction in the clearance of proteins in the lysosome and during autophagy has been shown to contribute to neurodegeneration. This review summarizes the recent knowledge about the role of PS proteins and γ-secretase in membrane protein metabolism and trafficking, and the functional relation to lysosomal activity and autophagy.
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Affiliation(s)
- Naoto Oikawa
- Department of Neurology, University of Bonn, 53127 Bonn, Germany.
| | - Jochen Walter
- Department of Neurology, University of Bonn, 53127 Bonn, Germany.
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15
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Nash Y, Schmukler E, Trudler D, Pinkas-Kramarski R, Frenkel D. DJ-1 deficiency impairs autophagy and reduces alpha-synuclein phagocytosis by microglia. J Neurochem 2017; 143:584-594. [PMID: 28921554 DOI: 10.1111/jnc.14222] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 08/26/2017] [Accepted: 09/11/2017] [Indexed: 01/06/2023]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder, of which 1% of the hereditary cases are linked to mutations in DJ-1, an oxidative stress sensor. The pathological hallmark of PD is intercellular inclusions termed Lewy Bodies, composed mainly of α-Synuclein (α-Syn) protein. Recent findings have shown that α-Syn can be transmitted from cell to cell, suggesting an important role of microglia, as the main scavenger cells of the brain, in clearing α-Syn. We previously reported that the knock down (KD) of DJ-1 in microglia increased cells' neurotoxicity to dopaminergic neurons. Here, we discovered that α-Syn significantly induced elevated secretion of the proinflammatory cytokines IL-6 and IL-1β and a significant dose-dependent elevation in the production of nitric oxide in DJ-1 KD microglia, compared to control microglia. We further investigated the ability of DJ-1 KD microglia to uptake and degrade soluble α-Syn, and discovered that DJ-1 KD reduces cell-surface lipid raft expression in microglia and impairs their ability to uptake soluble α-Syn. Autophagy is an important mechanism for degradation of intracellular proteins and organelles. We discovered that DJ-1 KD microglia exhibit an impaired autophagy-dependent degradation of p62 and LC3 proteins, and that manipulation of autophagy had less effect on α-Syn uptake and clearance in DJ-1 KD microglia, compared to control microglia. Further studies of the link between DJ-1, α-Syn uptake and autophagy may provide useful insights into the role of microglia in the etiology of the PD.
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Affiliation(s)
- Yuval Nash
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Eran Schmukler
- Department of Neurobiology George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Dorit Trudler
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,Department of Neurobiology George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ronit Pinkas-Kramarski
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,Department of Neurobiology George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Dan Frenkel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,Department of Neurobiology George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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16
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Regulated intramembrane proteolysis: emergent role in cell signalling pathways. Biochem Soc Trans 2017; 45:1185-1202. [PMID: 29079648 DOI: 10.1042/bst20170002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 12/12/2022]
Abstract
Receptor signalling events including those initiated following activation of cytokine and growth factor receptors and the well-characterised death receptors (tumour necrosis factor receptor, type 1, FasR and TRAIL-R1/2) are initiated at the cell surface through the recruitment and formation of intracellular multiprotein signalling complexes that activate divergent signalling pathways. Over the past decade, research studies reveal that many of these receptor-initiated signalling events involve the sequential proteolysis of specific receptors by membrane-bound proteases and the γ-secretase protease complexes. Proteolysis enables the liberation of soluble receptor ectodomains and the generation of intracellular receptor cytoplasmic domain fragments. The combined and sequential enzymatic activity has been defined as regulated intramembrane proteolysis and is now a fundamental signal transduction process involved in the termination or propagation of receptor signalling events. In this review, we discuss emerging evidence for a role of the γ-secretase protease complexes and regulated intramembrane proteolysis in cell- and immune-signalling pathways.
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17
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Walter J, Kemmerling N, Wunderlich P, Glebov K. γ-Secretase in microglia - implications for neurodegeneration and neuroinflammation. J Neurochem 2017; 143:445-454. [PMID: 28940294 DOI: 10.1111/jnc.14224] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/16/2017] [Accepted: 09/18/2017] [Indexed: 12/13/2022]
Abstract
γ-Secretase is an intramembrane cleaving protease involved in the generation of the Alzheimer's disease (AD)-associated amyloid β peptide (Aβ). γ-Secretase is ubiquitously expressed in different organs, and also in different cell types of the human brain. Besides the involvement in the proteolytic generation of Aβ from the amyloid precursor protein, γ-secretase cleaves many additional protein substrates, suggesting pleiotropic functions under physiological and pathophysiological conditions. Microglia exert important functions during brain development and homeostasis in adulthood, and accumulating evidence indicates that microglia and neuroinflammatory processes contribute to the pathogenesis of neurodegenerative diseases. Recent studies demonstrate functional implications of γ-secretase in microglia, suggesting that alterations in γ-secretase activity could contribute to AD pathogenesis by modulation of microglia and related neuroinflammatory processes during neurodegeneration. In this review, we discuss the involvement of γ-secretase in the regulation of microglial functions, and the potential relevance of these processes under physiological and pathophysiological conditions. This article is part of the series "Beyond Amyloid".
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Affiliation(s)
- Jochen Walter
- Department of Neurology, University of Bonn, Bonn, Germany
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18
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Herz J, Filiano AJ, Wiltbank AT, Yogev N, Kipnis J. Myeloid Cells in the Central Nervous System. Immunity 2017; 46:943-956. [PMID: 28636961 PMCID: PMC5657250 DOI: 10.1016/j.immuni.2017.06.007] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/17/2017] [Accepted: 06/02/2017] [Indexed: 02/07/2023]
Abstract
The central nervous system (CNS) and its meningeal coverings accommodate a diverse myeloid compartment that includes parenchymal microglia and perivascular macrophages, as well as choroid plexus and meningeal macrophages, dendritic cells, and granulocytes. These myeloid populations enjoy an intimate relationship with the CNS, where they play an essential role in both health and disease. Although the importance of these cells is clearly recognized, their exact function in the CNS continues to be explored. Here, we review the subsets of myeloid cells that inhabit the parenchyma, meninges, and choroid plexus and discuss their roles in CNS homeostasis. We also discuss the role of these cells in various neurological pathologies, such as autoimmunity, mechanical injury, neurodegeneration, and infection. We highlight the neuroprotective nature of certain myeloid cells by emphasizing their therapeutic potential for the treatment of neurological conditions.
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Affiliation(s)
- Jasmin Herz
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Anthony J Filiano
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
| | - Ashtyn T Wiltbank
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Nir Yogev
- Gutenberg Research Fellowship Group of Neuroimmunology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA; Gutenberg Research Fellowship Group of Neuroimmunology, Focus Program Translational Neuroscience and Immunotherapy, Rhine Main Neuroscience Network, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
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19
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Wu X, Kosaraju J, Zhou W, Tam KY. Neuroprotective Effect of SLM, a Novel Carbazole-Based Fluorophore, on SH-SY5Y Cell Model and 3xTg-AD Mouse Model of Alzheimer's Disease. ACS Chem Neurosci 2017; 8:676-685. [PMID: 28032988 DOI: 10.1021/acschemneuro.6b00388] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Amyloid β (Aβ) peptide aggregating to form a neurotoxic plaque, leading to cognitive deficits, is believed to be one of the plausible mechanisms for Alzheimer's disease (AD). Inhibiting Aβ aggregation is supposed to offer a neuroprotective effect to ameliorate AD. A previous report has shown that SLM, a carbazole-based fluorophore, binds to Aβ to inhibit the aggregation. However, it is not entirely clear whether the inhibition of Aβ aggregation alone would lead to the anticipated neuroprotective effects. In the current study, we intended to examine the protective action of SLM against Aβ-induced neurotoxicity in vitro and to evaluate if SLM can decrease the cognitive and behavioral deficits observed in triple transgenic AD mouse model (3xTg-AD). In the in vitro study, neurotoxicity induced by Aβ42 in human neuroblastoma (SH-SY5Y) cells was found to be reduced through the treatment with SLM. In the in vivo study, following one month SLM intraperitoneal injection (1, 2, and 4 mg/kg), 3xTg-AD mice were tested on Morris water maze (MWM) and Y-maze for their cognitive ability and sacrificed for biochemical estimations. Results show that SLM treatment improved the learning and memory ability in 3xTg-AD mice in MWM and Y-maze tasks. SLM also mitigated the amyloid burden by decreasing brain Aβ40 and Aβ42 levels and reduced tau phosphorylation, glycogen synthase kinase-3β activity, and neuro-inflammation. From our observations, SLM shows neuroprotection in SH-SY5Y cells against Aβ42 and also in 3xTg-AD mouse model by mitigating the pathological features and behavioral impairments.
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Affiliation(s)
- Xiaoli Wu
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Jayasankar Kosaraju
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Wei Zhou
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
| | - Kin Yip Tam
- Drug Development Core, Faculty
of Health Sciences, University of Macau, Taipa, Macau, China
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20
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Anti-inflammatory and protective effects of MT-031, a novel multitarget MAO-A and AChE/BuChE inhibitor in scopolamine mouse model and inflammatory cells. Neuropharmacology 2017; 113:445-456. [DOI: 10.1016/j.neuropharm.2016.10.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/10/2016] [Accepted: 10/27/2016] [Indexed: 12/20/2022]
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21
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Simonovitch S, Schmukler E, Bespalko A, Iram T, Frenkel D, Holtzman DM, Masliah E, Michaelson DM, Pinkas-Kramarski R. Impaired Autophagy in APOE4 Astrocytes. J Alzheimers Dis 2016; 51:915-27. [PMID: 26923027 DOI: 10.3233/jad-151101] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia in elderly. Genetic studies revealed allelic segregation of the apolipoprotein E (ApoE) gene in sporadic AD and in families with higher risk of AD. The mechanisms underlying the pathological effects of ApoE4 are not yet entirely clear. Several studies indicate that autophagy, which plays an important role in degradation pathways of proteins, organelles and protein aggregates, may be impaired in AD. In the present study, we investigated the effects of ApoE4 versus the ApoE3 isoform on the process of autophagy in mouse-derived astrocytes. The results obtained reveal that under several autophagy-inducing conditions, astrocytes expressing ApoE4 exhibit lower autophagic flux compared to astrocytes expressing ApoE3. Using an in situ model, we examined the role of autophagy and the effects thereon of ApoE4 in the elimination of Aβ plaques from isolated brain sections of transgenic 5xFAD mice. This revealed that ApoE4 astrocytes eliminate Aβ plaques less effectively than the corresponding ApoE3 astrocytes. Additional experiments showed that the autophagy inducer, rapamycin, enhances Aβ plaque degradation by ApoE4 astrocytes whereas the autophagy inhibitor, chloroquine, blocks Aβ plaque degradation by ApoE3 astrocytes. Taken together, these findings show that ApoE4 impairs autophagy in astrocyte cultures and that this effect is associated with reduced capacity to clear Aβ plaques. This suggests that impaired autophagy may play a role in mediating the pathological effects of ApoE4 in AD.
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Affiliation(s)
| | - Eran Schmukler
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
| | - Alina Bespalko
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
| | - Tal Iram
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
| | - Dan Frenkel
- Department of Neurobiology, Tel-Aviv University, Ramat-Aviv, Israel
| | - David M Holtzman
- Washington University School of Medicine, Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, St. Louis, MO, USA
| | - Eliezer Masliah
- Department of Neuroscience, University of California at San Diego, San Diego, CA, USA
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22
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Iram T, Trudler D, Kain D, Kanner S, Galron R, Vassar R, Barzilai A, Blinder P, Fishelson Z, Frenkel D. Astrocytes from old Alzheimer's disease mice are impaired in Aβ uptake and in neuroprotection. Neurobiol Dis 2016; 96:84-94. [DOI: 10.1016/j.nbd.2016.08.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/11/2016] [Accepted: 08/16/2016] [Indexed: 10/21/2022] Open
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23
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Sawmiller D, Habib A, Li S, Darlington D, Hou H, Tian J, Shytle RD, Smith A, Giunta B, Mori T, Tan J. Diosmin reduces cerebral Aβ levels, tau hyperphosphorylation, neuroinflammation, and cognitive impairment in the 3xTg-AD mice. J Neuroimmunol 2016; 299:98-106. [PMID: 27725131 DOI: 10.1016/j.jneuroim.2016.08.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/29/2016] [Accepted: 08/31/2016] [Indexed: 02/08/2023]
Abstract
Naturally-occurring bioactive flavonoids such as diosmin significantly reduces amyloid beta (Aβ) associated pathology in Alzheimer's disease (AD) mouse models. In the present study, oral administration of diosmin reduced cerebral Aβ oligomer levels, tau-hyperphosphorylation and cognitive impairment in the 3xTg-AD mouse model through glycogen synthase kinase-3 (GSK-3) and transient receptor potential canonical 6-related mechanisms. Diosmetin, one major bioactive metabolite of diosmin, increased inhibitory GSK-3β phosphorylation, while selectively reducing γ-secretase activity, Aβ generation, tau hyperphosphorylation and pro-inflammatory activation of microglia in vitro, without altering Notch processing. Therefore, both diosmin and diosmetin could be considered as potential candidates for novel anti-AD therapy.
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Affiliation(s)
- Darrell Sawmiller
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; James A. Haley Veteran's Administration Hospital, Tampa, FL, United States.
| | - Ahsan Habib
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Song Li
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; Center for Translational Research on Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Donna Darlington
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Huayan Hou
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Jun Tian
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - R Douglas Shytle
- Center for Aging & Brain Repair, Department of Neurosurgery & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Adam Smith
- Center for Aging & Brain Repair, Department of Neurosurgery & Brain Repair, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Brian Giunta
- Neuroimmunology Laboratory, Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Takashi Mori
- Departments of Biomedical Sciences and Pathology, Saitama Medical Center and Saitama Medical University, Kawagoe, Saitama, Japan
| | - Jun Tan
- Department of Psychiatry, Morsani College of Medicine, University of South Florida, Tampa, FL, United States; James A. Haley Veteran's Administration Hospital, Tampa, FL, United States.
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24
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Ries M, Sastre M. Mechanisms of Aβ Clearance and Degradation by Glial Cells. Front Aging Neurosci 2016; 8:160. [PMID: 27458370 PMCID: PMC4932097 DOI: 10.3389/fnagi.2016.00160] [Citation(s) in RCA: 340] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 06/17/2016] [Indexed: 12/24/2022] Open
Abstract
Glial cells have a variety of functions in the brain, ranging from immune defense against external and endogenous hazardous stimuli, regulation of synaptic formation, calcium homeostasis, and metabolic support for neurons. Their dysregulation can contribute to the development of neurodegenerative disorders, including Alzheimer’s disease (AD). One of the most important functions of glial cells in AD is the regulation of Amyloid-β (Aβ) levels in the brain. Microglia and astrocytes have been reported to play a central role as moderators of Aβ clearance and degradation. The mechanisms of Aβ degradation by glial cells include the production of proteases, including neprilysin, the insulin degrading enzyme, and the endothelin-converting enzymes, able to hydrolyse Aβ at different cleavage sites. Besides these enzymes, other proteases have been described to have some role in Aβ elimination, such as plasminogen activators, angiotensin-converting enzyme, and matrix metalloproteinases. Other relevant mediators that are released by glial cells are extracellular chaperones, involved in the clearance of Aβ alone or in association with receptors/transporters that facilitate their exit to the blood circulation. These include apolipoproteins, α2macroglobulin, and α1-antichymotrypsin. Finally, astrocytes and microglia have an essential role in phagocytosing Aβ, in many cases via a number of receptors that are expressed on their surface. In this review, we examine all of these mechanisms, providing an update on the latest research in this field.
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Affiliation(s)
- Miriam Ries
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital London, UK
| | - Magdalena Sastre
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital London, UK
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Oron A, Oron U. Low-Level Laser Therapy to the Bone Marrow Ameliorates Neurodegenerative Disease Progression in a Mouse Model of Alzheimer's Disease: A Minireview. Photomed Laser Surg 2016; 34:627-630. [PMID: 27294393 DOI: 10.1089/pho.2015.4072] [Citation(s) in RCA: 268] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE This communication reviews the ability of low-level laser therapy (LLLT) to stimulate mesenchymal stem cells (MSCs) in autologous bone marrow (BM) to enhance the capacity of MSCs to infiltrate the brain, clear β-amyloid, and improve cognition. BACKGROUND We recently reported that LLLT applied to the BM enhanced the proliferation of MSCs and their mobilization toward the ischemic heart region, suggesting a possible application of this approach in regenerative medicine and neurodegenerative diseases. It was also shown that circulating monocytes can infiltrate the brain and reduce brain amyloid load in an Alzheimer's disease (AD) mouse model. METHODS AND RESULTS MSCs from wild-type mice stimulated with LLLT demonstrated an increased ability to maturate toward a monocyte lineage and to increase phagocytosis of soluble Aβ in vitro. Furthermore, weekly LLLT for 2 months to the BM, starting at 4 months of age (progressive stage of the disease in these 5XFAD transgenic male mice), improved memory and spatial learning, compared to a sham-treated AD mouse model. Histology revealed a significant reduction in Aβ brain burden in the laser-treated mice compared to the nonlaser-treated ones. CONCLUSIONS The application of LLLT to the BM is suggested as a therapeutic approach in progressive stages of AD, and its potential role in mediating MSC therapy in brain amyloidogenic disease is implied.
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Affiliation(s)
- Amir Oron
- 1 Department of Orthopedic Surgery, Kaplan Medical Center , Rehovot, Israel
| | - Uri Oron
- 2 Department of Zoology, George S. Wise Faculty of Life Sciences and Sagol School of Neuroscience, Tel Aviv University , Tel Aviv, Israel
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Farfara D, Tuby H, Trudler D, Doron-Mandel E, Maltz L, Vassar RJ, Frenkel D, Oron U. Low-level laser therapy ameliorates disease progression in a mouse model of Alzheimer's disease. J Mol Neurosci 2014; 55:430-6. [PMID: 24994540 DOI: 10.1007/s12031-014-0354-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/11/2014] [Indexed: 01/01/2023]
Abstract
Low-level laser therapy (LLLT) has been used to treat inflammation, tissue healing, and repair processes. We recently reported that LLLT to the bone marrow (BM) led to proliferation of mesenchymal stem cells (MSCs) and their homing in the ischemic heart suggesting its role in regenerative medicine. The aim of the present study was to investigate the ability of LLLT to stimulate MSCs of autologous BM in order to affect neurological behavior and β-amyloid burden in progressive stages of Alzheimer's disease (AD) mouse model. MSCs from wild-type mice stimulated with LLLT showed to increase their ability to maturate towards a monocyte lineage and to increase phagocytosis activity towards soluble amyloid beta (Aβ). Furthermore, weekly LLLT to BM of AD mice for 2 months, starting at 4 months of age (progressive stage of AD), improved cognitive capacity and spatial learning, as compared to sham-treated AD mice. Histology revealed a significant reduction in Aβ brain burden. Our results suggest the use of LLLT as a therapeutic application in progressive stages of AD and imply its role in mediating MSC therapy in brain amyloidogenic diseases.
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Affiliation(s)
- Dorit Farfara
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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27
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Trudler D, Weinreb O, Mandel SA, Youdim MBH, Frenkel D. DJ-1 deficiency triggers microglia sensitivity to dopamine toward a pro-inflammatory phenotype that is attenuated by rasagiline. J Neurochem 2014; 129:434-47. [PMID: 24355073 DOI: 10.1111/jnc.12633] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 10/31/2013] [Accepted: 12/02/2013] [Indexed: 12/21/2022]
Abstract
DJ-1 is an oxidative stress sensor that localizes to the mitochondria when the cell is exposed to oxidative stress. DJ-1 mutations that result in gene deficiency are linked to increased risk of Parkinson's disease (PD). Activation of microglial stress conditions that are linked to PD may result in neuronal death. We postulated that DJ-1 deficiency may increase microglial neurotoxicity. We found that down-regulation of DJ-1 in microglia using an shRNA approach increased cell sensitivity to dopamine as measured by secreted pro-inflammatory cytokines such as IL-1β and IL-6. Furthermore, we discovered that DJ-1-deficient microglia had increased monoamine oxidase activity that resulted in elevation of intracellular reactive oxygen species and nitric oxide leading to increased dopaminergic neurotoxicity. Rasagaline, a monoamine oxidase inhibitor approved for treatment of PD, reduced the microglial pro-inflammatory phenotype and significantly reduced neurotoxicity. Moreover, we discovered that DJ-1-deficient microglia have reduced expression of triggering receptor expressed on myeloid cells 2 (TREM2), previously suggested as a risk factor for pro-inflammation in neurodegenerative diseases. Further studies of DJ-1-mediated cellular pathways in microglia may contribute useful insights into the development of PD providing future avenues for therapeutic intervention
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Affiliation(s)
- Dorit Trudler
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Smolarkiewicz M, Skrzypczak T, Wojtaszek P. The very many faces of presenilins and the γ-secretase complex. PROTOPLASMA 2013; 250:997-1011. [PMID: 23504135 PMCID: PMC3788181 DOI: 10.1007/s00709-013-0494-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/01/2013] [Indexed: 05/02/2023]
Abstract
Presenilin is a central, catalytic component of the γ-secretase complex which conducts intramembrane cleavage of various protein substrates. Although identified and mainly studied through its role in the development of amyloid plaques in Alzheimer disease, γ-secretase has many other important functions. The complex seems to be evolutionary conserved throughout the Metazoa, but recent findings in plants and Dictyostelium discoideum as well as in archeons suggest that its evolution and functions might be much more diversified than previously expected. In this review, a selective survey of the multitude of functions of presenilins and the γ-secretase complex is presented. Following a brief overview of γ-secretase structure, assembly and maturation, three functional aspects are analyzed: (1) the role of γ-secretase in autophagy and phagocytosis; (2) involvement of the complex in signaling related to endocytosis; and (3) control of calcium fluxes by presenilins.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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29
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Wunderlich P, Glebov K, Kemmerling N, Tien NT, Neumann H, Walter J. Sequential proteolytic processing of the triggering receptor expressed on myeloid cells-2 (TREM2) protein by ectodomain shedding and γ-secretase-dependent intramembranous cleavage. J Biol Chem 2013; 288:33027-36. [PMID: 24078628 DOI: 10.1074/jbc.m113.517540] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM2) and its signaling adaptor protein TYROBP/DAP12 play important roles in signal transduction in dendritic cells, osteoclasts, tissue macrophages, and microglia. Recently, TREM2 variants have been shown to be linked to late onset Alzheimer disease. Here, we demonstrate that TREM2 undergoes sequential proteolytic processing by ectodomain shedding and intramembrane proteolysis. The C-terminal fragment (CTF) of TREM2 generated by ectodomain shedding is cleaved by γ-secretase. Importantly, pharmacologic and genetic γ-secretase inhibition resulted in accumulation of TREM2 CTF at the plasma membrane that also interacts with the signaling adaptor protein DAP12. Thus, the accumulated TREM2 CTF thereby might limit the interaction of DAP12 with the functional full-length receptor, resulting in decreased DAP12 phosphorylation and impaired metabolism of phosphatidylinositol 4,5-bisphosphate. Together, these data demonstrate γ-secretase-mediated intramembranous proteolysis of TREM2 and functionally link two Alzheimer disease-associated proteins in one signaling pathway.
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Affiliation(s)
- Patrick Wunderlich
- From the Department of Neurology, University of Bonn, 53127 Bonn, Germany and
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30
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Ma Y, Bao J, Zhao X, Shen H, Lv J, Ma S, Zhang X, Li Z, Wang S, Wang Q, Ji J. Activated cyclin-dependent kinase 5 promotes microglial phagocytosis of fibrillar β-amyloid by up-regulating lipoprotein lipase expression. Mol Cell Proteomics 2013; 12:2833-44. [PMID: 23816988 DOI: 10.1074/mcp.m112.026864] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Amyloid plaques are crucial for the pathogenesis of Alzheimer disease (AD). Phagocytosis of fibrillar β-amyloid (Aβ) by activated microglia is essential for Aβ clearance in Alzheimer disease. However, the mechanism underlying Aβ clearance in the microglia remains unclear. In this study, we performed stable isotope labeling of amino acids in cultured cells for quantitative proteomics analysis to determine the changes in protein expression in BV2 microglia treated with or without Aβ. Among 2742 proteins identified, six were significantly up-regulated and seven were down-regulated by Aβ treatment. Bioinformatic analysis revealed strong over-representation of membrane proteins, including lipoprotein lipase (LPL), among proteins regulated by the Aβ stimulus. We verified that LPL expression increased at both mRNA and protein levels in response to Aβ treatment in BV2 microglia and primary microglial cells. Silencing of LPL reduced microglial phagocytosis of Aβ, but did not affect degradation of internalized Aβ. Importantly, we found that enhanced cyclin-dependent kinase 5 (CDK5) activity by increasing p35-to-p25 conversion contributed to LPL up-regulation and promoted Aβ phagocytosis in microglia, whereas inhibition of CDK5 reduced LPL expression and Aβ internalization. Furthermore, Aβ plaques was increased with reducing p25 and LPL level in APP/PS1 mouse brains, suggesting that CDK5/p25 signaling plays a crucial role in microglial phagocytosis of Aβ. In summary, our findings reveal a potential role of the CDK5/p25-LPL signaling pathway in Aβ phagocytosis by microglia and provide a new insight into the molecular pathogenesis of Alzheimer disease.
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Affiliation(s)
- Yuanhui Ma
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
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Segev-Amzaleg N, Trudler D, Frenkel D. Preconditioning to mild oxidative stress mediates astroglial neuroprotection in an IL-10-dependent manner. Brain Behav Immun 2013; 30:176-85. [PMID: 23313057 DOI: 10.1016/j.bbi.2012.12.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 12/21/2012] [Accepted: 12/22/2012] [Indexed: 12/20/2022] Open
Abstract
Oxidative stress plays an important role in the pathogenesis of various brain insults, including stroke. Astroglia are the main glial cells that play a fundamental role in maintaining the homeostasis of the CNS. They are important for protection from injury and aid the brain in functional recovery after injuries. It has been shown that the brain can be prepared to withstand an oxidative stress insult by a process known as preconditioning. We used primary astroglial cell culture to investigate whether preconditioning to mild oxidative stress and glucose deprivation (OSGD) can increase both astroglia survival and neuroprotective features. We found that preconditioning astroglia to mild OSGD increases astroglial survival of a second insult through activation of the NF-E2-related factor-2 (Nrf-2) pathway. Moreover, we found that Nrf-2 is highly expressed in adult brain astroglia and that preconditioning to OSGD in vivo, such as in a murine model of ischemic stroke, leads to a significant increase in astroglial Nrf-2 expression. Furthermore, we discovered an increase in neuroprotection, as measured by increased neuronal cell survival, following OSGD in the presence of medium from astroglia exposed to a mild OSGD condition. Interestingly, we discovered a significant increase in astroglial secretion of the anti-inflammatory cytokine IL-10 vs. the pro-inflammatory cytokine IL-1β in mild vs. severe oxidative stress, respectively. We demonstrated that preconditioning astroglia to mild oxidative stress increases neuroprotection in an IL-10-dependent manner. By using tert-butylhydroquinone (tBHQ), a known specific activator of Nrf-2, we found that Nrf-2 can enhance IL-10 expression. Further studies of Nrf-2-mediated cellular pathways in astroglia through IL-10 may provide useful insights into the development of therapeutic interventions following oxidative stress insults such as ischemic stroke.
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Affiliation(s)
- Niva Segev-Amzaleg
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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32
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Processing of the platelet amyloid precursor protein in the mild cognitive impairment (MCI). Neurochem Res 2013; 38:1415-23. [PMID: 23575575 DOI: 10.1007/s11064-013-1039-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/12/2013] [Accepted: 04/03/2013] [Indexed: 10/27/2022]
Abstract
It has been suggested that mild cognitive impairment (MCI) patients deteriorate faster than the healthy elderly population and have an increased risk of developing dementia. Certain blood molecular biomarkers have been identified as prognostic markers in Alzheimer's disease (AD). The present study was aimed to assess the status of the platelet amyloid precursor protein (APP) metabolism in MCI and AD subjects and establish to what extent any variation could have a prognostic value suggestive of predictive AD in MCI patients. Thirty-four subjects diagnosed with MCI and 45 subjects with AD were compared to 28 healthy elderly individuals for assessing for protein levels of APP, β-APP cleaving enzyme 1 (BACE1), presenilin 1 (PS1) and a disintegrin and metalloproteinase-10 (ADAM-10) by western blot, and for the enzyme activities of BACE1 and γ-secretase by using specific fluorogenic substrates, in samples of platelets. A similar pattern in the healthy elderly and MCI patients was found for BACE1 and PS1 levels. A reduction of APP levels in MCI and AD patients compared with healthy elderly individuals was found. Augmented levels of ADAM-10 in both MCI and AD were displayed in comparison with age-matched control subjects. The ratio ADAM-10/BACE1 was higher for the MCI group versus AD group. Whereas BACE1 and PS1 levels were only increased in AD regarding to controls, BACE1 and γ-secretase activities augmented significantly in both MCI and AD groups. Finally, differences and similarities between MCI and AD patients were observed in several markers of platelet APP processing. Larger sample sets from diverse populations need to be analyzed to define a signature for the presence of MCI or AD pathology and to early detect AD at the MCI stage.
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Krabbe G, Halle A, Matyash V, Rinnenthal JL, Eom GD, Bernhardt U, Miller KR, Prokop S, Kettenmann H, Heppner FL. Functional impairment of microglia coincides with Beta-amyloid deposition in mice with Alzheimer-like pathology. PLoS One 2013; 8:e60921. [PMID: 23577177 PMCID: PMC3620049 DOI: 10.1371/journal.pone.0060921] [Citation(s) in RCA: 332] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 03/04/2013] [Indexed: 11/20/2022] Open
Abstract
Microglial cells closely interact with senile plaques in Alzheimer’s disease and acquire the morphological appearance of an activated phenotype. The significance of this microglial phenotype and the impact of microglia for disease progression have remained controversial. To uncover and characterize putative changes in the functionality of microglia during Alzheimer’s disease, we directly assessed microglial behavior in two mouse models of Alzheimer’s disease. Using in vivo two-photon microscopy and acute brain slice preparations, we found that important microglial functions - directed process motility and phagocytic activity - were strongly impaired in mice with Alzheimer’s disease-like pathology compared to age-matched non-transgenic animals. Notably, impairment of microglial function temporally and spatially correlated with Aβ plaque deposition, and phagocytic capacity of microglia could be restored by interventionally decreasing amyloid burden by Aβ vaccination. These data suggest that major microglial functions progressively decline in Alzheimer’s disease with the appearance of Aβ plaques, and that this functional impairment is reversible by lowering Aβ burden, e.g. by means of Aβ vaccination.
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Affiliation(s)
- Grietje Krabbe
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany
| | - Annett Halle
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Vitali Matyash
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany
| | - Jan L. Rinnenthal
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Gina D. Eom
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ulrike Bernhardt
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Kelly R. Miller
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Stefan Prokop
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Helmut Kettenmann
- Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany
- * E-mail: (HK); (FLH)
| | - Frank L. Heppner
- Department of Neuropathology, Charité-Universitätsmedizin Berlin, Berlin, Germany
- * E-mail: (HK); (FLH)
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34
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Sierra A, Abiega O, Shahraz A, Neumann H. Janus-faced microglia: beneficial and detrimental consequences of microglial phagocytosis. Front Cell Neurosci 2013. [PMID: 23386811 DOI: 10.3389/fncel.2013.00006/abstract] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and microbes. In addition, microglia phagocytoses brain-specific cargo, such as axonal and myelin debris in spinal cord injury or multiple sclerosis, amyloid-β deposits in Alzheimer's disease, and supernumerary synapses in postnatal development. Common mechanisms of recognition, engulfment, and degradation of the different types of cargo are assumed, but very little is known about the shared and specific molecules involved in the phagocytosis of each target by microglia. More importantly, the functional consequences of microglial phagocytosis remain largely unexplored. Overall, phagocytosis is considered a beneficial phenomenon, since it eliminates dead cells and induces an anti-inflammatory response. However, phagocytosis can also activate the respiratory burst, which produces toxic reactive oxygen species (ROS). Phagocytosis has been traditionally studied in pathological conditions, leading to the assumption that microglia have to be activated in order to become efficient phagocytes. Recent data, however, has shown that unchallenged microglia phagocytose apoptotic cells during development and in adult neurogenic niches, suggesting an overlooked role in brain remodeling throughout the normal lifespan. The present review will summarize the current state of the literature regarding the role of microglial phagocytosis in maintaining tissue homeostasis in health as in disease.
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Affiliation(s)
- Amanda Sierra
- Achucarro-Basque Center for Neuroscience Zamudio, Spain ; Department of Neuroscience, University of the Basque Country EHU/UPV Leioa, Spain ; Ikerbasque-Basque Foundation for Science Bilbao, Spain
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35
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Sierra A, Abiega O, Shahraz A, Neumann H. Janus-faced microglia: beneficial and detrimental consequences of microglial phagocytosis. Front Cell Neurosci 2013; 7:6. [PMID: 23386811 PMCID: PMC3558702 DOI: 10.3389/fncel.2013.00006] [Citation(s) in RCA: 394] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/09/2013] [Indexed: 02/04/2023] Open
Abstract
Microglia are the resident brain macrophages and they have been traditionally studied as orchestrators of the brain inflammatory response during infections and disease. In addition, microglia has a more benign, less explored role as the brain professional phagocytes. Phagocytosis is a term coined from the Greek to describe the receptor-mediated engulfment and degradation of dead cells and microbes. In addition, microglia phagocytoses brain-specific cargo, such as axonal and myelin debris in spinal cord injury or multiple sclerosis, amyloid-β deposits in Alzheimer's disease, and supernumerary synapses in postnatal development. Common mechanisms of recognition, engulfment, and degradation of the different types of cargo are assumed, but very little is known about the shared and specific molecules involved in the phagocytosis of each target by microglia. More importantly, the functional consequences of microglial phagocytosis remain largely unexplored. Overall, phagocytosis is considered a beneficial phenomenon, since it eliminates dead cells and induces an anti-inflammatory response. However, phagocytosis can also activate the respiratory burst, which produces toxic reactive oxygen species (ROS). Phagocytosis has been traditionally studied in pathological conditions, leading to the assumption that microglia have to be activated in order to become efficient phagocytes. Recent data, however, has shown that unchallenged microglia phagocytose apoptotic cells during development and in adult neurogenic niches, suggesting an overlooked role in brain remodeling throughout the normal lifespan. The present review will summarize the current state of the literature regarding the role of microglial phagocytosis in maintaining tissue homeostasis in health as in disease.
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Affiliation(s)
- Amanda Sierra
- Achucarro-Basque Center for Neuroscience Zamudio, Spain ; Department of Neuroscience, University of the Basque Country EHU/UPV Leioa, Spain ; Ikerbasque-Basque Foundation for Science Bilbao, Spain
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36
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Cimino PJ, Yang Y, Li X, Hemingway JF, Cherne MK, Khademi SB, Fukui Y, Montine KS, Montine TJ, Keene CD. Ablation of the microglial protein DOCK2 reduces amyloid burden in a mouse model of Alzheimer's disease. Exp Mol Pathol 2013; 94:366-71. [PMID: 23318649 DOI: 10.1016/j.yexmp.2013.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/04/2013] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease (AD) neuropathology is characterized by innate immune activation primarily through prostaglandin E2 (PGE2) signaling. Dedicator of cytokinesis 2 (DOCK2) is a guanyl nucleotide exchange factor expressed exclusively in microglia in the brain and is regulated by PGE2 receptor EP2. DOCK2 modulates microglia cytokine secretion, phagocytosis, and paracrine neurotoxicity. EP2 ablation in experimental AD results in reduced oxidative damage and amyloid beta (Aβ) burden. This discovery led us to hypothesize that genetic ablation of DOCK2 would replicate the anti-Aβ effects of loss of EP2 in experimental AD. To test this hypothesis, we crossed mice that lacked DOCK2 (DOCK2-/-), were hemizygous for DOCK2 (DOCK2+/-), or that expressed two DOCK2 genes (DOCK2+/+) with APPswe-PS1Δe9 mice (a model of AD). While we found no DOCK2-dependent differences in cortex or in hippocampal microglia density or morphology in APPswe-PS1Δe9 mice, cerebral cortical and hippocampal Aβ plaque area and size were significantly reduced in 10-month-old APPswe-PS1Δe9/DOCK2-/- mice compared with APPswe-PS1Δe9/DOCK2+/+ controls. DOCK2 hemizygous APPswe-PS1Δe9 mice had intermediate Aβ plaque levels. Interestingly, soluble Aβ42 was not significantly different among the three genotypes, suggesting the effects were mediated specifically in fibrillar Aβ. In combination with earlier cell culture results, our in vivo results presented here suggest DOCK2 contributes to Aβ plaque burden via regulation of microglial innate immune function and may represent a novel therapeutic target for AD.
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Affiliation(s)
- Patrick J Cimino
- Department of Pathology, University of Washington, Seattle, WA 63110-1093, USA.
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Zhang X, Li L, Zhang X, Xie W, Li L, Yang D, Heng X, Du Y, Doody RS, Le W. Prenatal hypoxia may aggravate the cognitive impairment and Alzheimer's disease neuropathology in APPSwe/PS1A246E transgenic mice. Neurobiol Aging 2012; 34:663-78. [PMID: 22795785 DOI: 10.1016/j.neurobiolaging.2012.06.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/13/2012] [Accepted: 06/15/2012] [Indexed: 01/06/2023]
Abstract
Most cases of Alzheimer's disease (AD) arise through interactions between genetic and environmental factors. It is believed that hypoxia is an important environmental factor influencing the development of AD. Our group has previously demonstrated that hypoxia increased β-amyloid (Aβ) generation in aged AD mice. Here, we further investigate the pathological role of prenatal hypoxia in AD. We exposed the pregnant APP(Swe)/PS1(A246E) transgenic mice to high-altitude hypoxia in a hypobaric chamber during days 7-20 of gestation. We found that prenatal hypoxic mice exhibited a remarkable deficit in spatial learning and memory and a significant decrease in synapses. We also documented a significantly higher level of amyloid precursor protein, lower level of the Aβ-degrading enzyme neprilysin, and increased Aβ accumulation in the brain of prenatal hypoxic mice. Finally, we demonstrated striking neuropathologic changes in prenatal hypoxic AD mice, showing increased phosphorylation of tau, decreased hypoxia-induced factor, and enhanced activation of astrocytes and microglia. These data suggest that although the characteristic features of AD appear later in life, hypoxemia in the prenatal stage may contribute to the pathogenesis of the disease, supporting the notion that environmental factors can trigger or aggravate AD.
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Affiliation(s)
- Xin Zhang
- Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Sweepers in the CNS: Microglial Migration and Phagocytosis in the Alzheimer Disease Pathogenesis. Int J Alzheimers Dis 2012; 2012:891087. [PMID: 22666624 PMCID: PMC3359803 DOI: 10.1155/2012/891087] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/02/2012] [Indexed: 01/28/2023] Open
Abstract
Microglia are multifunctional immune cells in the central nervous system (CNS). In the neurodegenerative diseases such as Alzheimer's disease (AD), accumulation of glial cells, gliosis, occurs in the lesions. The role of accumulated microglia in the pathophysiology of AD is still controversial. When neuronal damage occurs, microglia exert diversified functions, including migration, phagocytosis, and production of various cytokines and chemokines. Among these, microglial phagocytosis of unwanted neuronal debris is critical to maintain the healthy neuronal networks. Microglia express many surface receptors implicated in phagocytosis. It has been suggested that the lack of microglial phagocytosis worsens pathology of AD and induces memory impairment. The present paper summarizes recent evidences on implication of microglial chemotaxis and phagocytosis in AD pathology and discusses the mechanisms related to chemotaxis toward injured neurons and phagocytosis of unnecessary debris.
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Abstract
Contrary to early views, we now know that systemic inflammatory/immune responses transmit to the brain. The microglia, the resident "macrophages" of the brain's innate immune system, are most responsive, and increasing evidence suggests that they enter a hyper-reactive state in neurodegenerative conditions and aging. As sustained over-production of microglial pro-inflammatory mediators is neurotoxic, this raises great concern that systemic inflammation (that also escalates with aging) exacerbates or possibly triggers, neurological diseases (Alzheimer's, prion, motoneuron disease). It is known that inflammation has an essential role in the progression of Alzheimer's disease (AD), since amyloid-β (Aβ) is able to activate microglia, initiating an inflammatory response, which could have different consequences for neuronal survival. On one hand, microglia may delay the progression of AD by contributing to the clearance of Aβ, since they phagocyte Aβ and release enzymes responsible for Aβ degradation. Microglia also secrete growth factors and anti-inflammatory cytokines, which are neuroprotective. In addition, microglia removal of damaged cells is a very important step in the restoration of the normal brain environment, as if left such cells can become potent inflammatory stimuli, resulting in yet further tissue damage. On the other hand, as we age microglia become steadily less efficient at these processes, tending to become over-activated in response to stimulation and instigating too potent a reaction, which may cause neuronal damage in its own right. Therefore, it is critical to understand the state of activation of microglia in different AD stages to be able to determine the effect of potential anti-inflammatory therapies. We discuss here recent evidence supporting both the beneficial or detrimental performance of microglia in AD, and the attempt to find molecules/biomarkers for early diagnosis or therapeutic interventions.
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Affiliation(s)
- Egle Solito
- Centre for Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and The London, Queen Mary’s School of Medicine and DentistryLondon, UK
| | - Magdalena Sastre
- Centre for Neuroscience, Division of Experimental Medicine, Imperial College LondonLondon, UK
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Animal Models of Alzheimer's Disease: Utilization of Transgenic Alzheimer's Disease Models in Studies of Amyloid Beta Clearance. ACTA ACUST UNITED AC 2012; 1:11-20. [PMID: 23440676 PMCID: PMC3575554 DOI: 10.1007/s13670-011-0004-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glial cells in Alzheimer’s disease (AD) have been shown to be capable of clearing or at least restricting the accumulation of toxic amyloid beta (Aβ) deposits. Recently, bone marrow (BM)–derived monocytic cells have been recognized in experimental studies to be superior in their phagocytic properties when compared to their brain endogenous counterparts. In human AD, BM-derived monocytic cells may have deficiencies in their capacity to restrict plaque growth. Therefore, enhancement of phagocytic properties of cells of monocyte origin, both brain endogenous microglia and BM-derived monocytic cells, offers an attractive therapeutic approach to fight off AD. Transgenic mouse models with aberrant Aβ deposition offer a valuable tool for discovery of novel pathways to facilitate cell-mediated Aβ uptake. This article reviews the most recent findings on the phagocytic capacity of cells with monocytic origin in various transgenic AD models and describes the methods to study phagocytic activity of these cells.
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