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Moreira R, Nóbrega C, de Almeida LP, Mendonça L. Brain-targeted drug delivery - nanovesicles directed to specific brain cells by brain-targeting ligands. J Nanobiotechnology 2024; 22:260. [PMID: 38760847 PMCID: PMC11100082 DOI: 10.1186/s12951-024-02511-7] [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: 02/15/2024] [Accepted: 04/29/2024] [Indexed: 05/19/2024] Open
Abstract
Neurodegenerative diseases are characterized by extensive loss of function or death of brain cells, hampering the life quality of patients. Brain-targeted drug delivery is challenging, with a low success rate this far. Therefore, the application of targeting ligands in drug vehicles, such as lipid-based and polymeric nanoparticles, holds the promise to overcome the blood-brain barrier (BBB) and direct therapies to the brain, in addition to protect their cargo from degradation and metabolization. In this review, we discuss the barriers to brain delivery and the different types of brain-targeting ligands currently in use in brain-targeted nanoparticles, such as peptides, proteins, aptamers, small molecules, and antibodies. Moreover, we present a detailed review of the different targeting ligands used to direct nanoparticles to specific brain cells, like neurons (C4-3 aptamer, neurotensin, Tet-1, RVG, and IKRG peptides), astrocytes (Aquaporin-4, D4, and Bradykinin B2 antibodies), oligodendrocytes (NG-2 antibody and the biotinylated DNA aptamer conjugated to a streptavidin core Myaptavin-3064), microglia (CD11b antibody), neural stem cells (QTRFLLH, VPTQSSG, and NFL-TBS.40-63 peptides), and to endothelial cells of the BBB (transferrin and insulin proteins, and choline). Reports demonstrated enhanced brain-targeted delivery with improved transport to the specific cell type targeted with the conjugation of these ligands to nanoparticles. Hence, this strategy allows the implementation of high-precision medicine, with reduced side effects or unwanted therapy clearance from the body. Nevertheless, the accumulation of some of these nanoparticles in peripheral organs has been reported indicating that there are still factors to be improved to achieve higher levels of brain targeting. This review is a collection of studies exploring targeting ligands for the delivery of nanoparticles to the brain and we highlight the advantages and limitations of this type of approach in precision therapies.
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Grants
- under BrainHealth2020 projects (CENTRO-01-0145-FEDER-000008), through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalization and Portuguese national funds via FCT - Fundação para a Ciência e a Tecnologia, under projects - UIDB/04539/2020 and UIDP/04539/2020, POCI-01-0145-FEDER-030737 (NeuroStemForMJD, PTDC/BTM-ORG/30737/2017), CEECIND/04242/2017, and PhD Scholarship European Regional Development Fund (ERDF) through the Centro 2020 Regional Operational Programme
- under BrainHealth2020 projects (CENTRO-01-0145-FEDER-000008), through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalization and Portuguese national funds via FCT - Fundação para a Ciência e a Tecnologia, under projects - UIDB/04539/2020 and UIDP/04539/2020, POCI-01-0145-FEDER-030737 (NeuroStemForMJD, PTDC/BTM-ORG/30737/2017), CEECIND/04242/2017, and PhD Scholarship European Regional Development Fund (ERDF) through the Centro 2020 Regional Operational Programme
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Affiliation(s)
- Ricardo Moreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, polo 1, Coimbra, FMUC, 3004-504, Portugal
- CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, 3004-504, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, 3000-548, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), University of Algarve, Faro, 8005-139, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, 8005-139, Portugal
| | - Luís Pereira de Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, polo 1, Coimbra, FMUC, 3004-504, Portugal
- CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, 3004-504, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, 3000-548, Portugal
- Institute of Interdisciplinary Research, University of Coimbra, Coimbra, 3030-789, Portugal
| | - Liliana Mendonça
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, polo 1, Coimbra, FMUC, 3004-504, Portugal.
- CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, 3004-504, Portugal.
- Institute of Interdisciplinary Research, University of Coimbra, Coimbra, 3030-789, Portugal.
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Vervuurt M, Kuiperij HB, de Kort AM, Kersten I, Klijn CJM, Schreuder FHBM, Verbeek MM. Proximity extension assay in cerebrospinal fluid identifies neurofilament light chain as biomarker of neurodegeneration in sporadic cerebral amyloid angiopathy. Alzheimers Res Ther 2024; 16:108. [PMID: 38745197 PMCID: PMC11092079 DOI: 10.1186/s13195-024-01473-0] [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: 12/21/2023] [Accepted: 05/01/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND Sporadic cerebral amyloid angiopathy (sCAA) is a disease characterised by the progressive deposition of the amyloid beta (Aβ) in the cerebral vasculature, capable of causing a variety of symptoms, from (mild) cognitive impairment, to micro- and major haemorrhagic lesions. Modern diagnosis of sCAA relies on radiological detection of late-stage hallmarks of disease, complicating early diagnosis and potential interventions in disease progression. Our goal in this study was to identify and validate novel biomarkers for sCAA. METHODS We performed a proximity extension assay (PEA) on cerebrospinal fluid (CSF) samples of sCAA/control participants (n = 34/51). Additionally, we attempted to validate the top candidate biomarker in CSF and serum samples (n = 38/26) in a largely overlapping validation cohort, through analysis with a targeted immunoassay. RESULTS Thirteen proteins were differentially expressed through PEA, with top candidate NFL significantly increased in CSF of sCAA patients (p < 0.0001). Validation analyses using immunoassays revealed increased CSF and serum NFL levels in sCAA patients (both p < 0.0001) with good discrimination between sCAA and controls (AUC: 0.85; AUC: 0.79 respectively). Additionally, the CSF: serum NFL ratio was significantly elevated in sCAA (p = 0.002). DISCUSSION Large-scale targeted proteomics screening of CSF of sCAA patients and controls identified thirteen biomarker candidates for sCAA. Orthogonal validation of NFL identified NFL in CSF and serum as biomarker, capable of differentiating between sCAA patients and controls.
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Affiliation(s)
- Marc Vervuurt
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - H Bea Kuiperij
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Anna M de Kort
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris Kersten
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J M Klijn
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Floris H B M Schreuder
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marcel M Verbeek
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands.
- Department of Human Genetics, Radboud University Medical Center, P.O. Box 9101, Nijmegen, 830 TML, 6500 HB, The Netherlands.
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3
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Gebril HM, Aryasomayajula A, de Lima MRN, Uhrich KE, Moghe PV. Nanotechnology for microglial targeting and inhibition of neuroinflammation underlying Alzheimer's pathology. Transl Neurodegener 2024; 13:2. [PMID: 38173014 PMCID: PMC10765804 DOI: 10.1186/s40035-023-00393-7] [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: 08/06/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is considered to have a multifactorial etiology. The hallmark of AD is progressive neurodegeneration, which is characterized by the deepening loss of memory and a high mortality rate in the elderly. The neurodegeneration in AD is believed to be exacerbated following the intercoupled cascades of extracellular amyloid beta (Aβ) plaques, uncontrolled microglial activation, and neuroinflammation. Current therapies for AD are mostly designed to target the symptoms, with limited ability to address the mechanistic triggers for the disease. In this study, we report a novel nanotechnology based on microglial scavenger receptor (SR)-targeting amphiphilic nanoparticles (NPs) for the convergent alleviation of fibril Aβ (fAβ) burden, microglial modulation, and neuroprotection. METHODS We designed a nanotechnology approach to regulate the SR-mediated intracellular fAβ trafficking within microglia. We synthesized SR-targeting sugar-based amphiphilic macromolecules (AM) and used them as a bioactive shell to fabricate serum-stable AM-NPs via flash nanoprecipitation. Using electron microscopy, in vitro approaches, ELISA, and confocal microscopy, we investigated the effect of AM-NPs on Aβ fibrilization, fAβ-mediated microglial inflammation, and neurotoxicity in BV2 microglia and SH-SY5Y neuroblastoma cell lines. RESULTS AM-NPs interrupted Aβ fibrilization, attenuated fAβ microglial internalization via targeting the fAβ-specific SRs, arrested the fAβ-mediated microglial activation and pro-inflammatory response, and accelerated lysosomal degradation of intracellular fAβ. Moreover, AM-NPs counteracted the microglial-mediated neurotoxicity after exposure to fAβ. CONCLUSIONS The AM-NP nanotechnology presents a multifactorial strategy to target pathological Aβ aggregation and arrest the fAβ-mediated pathological progression in microglia and neurons.
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Affiliation(s)
- Hoda M Gebril
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA.
| | - Aravind Aryasomayajula
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA
| | | | - Kathryn E Uhrich
- Department of Chemistry, University of California, 501 Big Springs Rd., Riverside, CA, 92507, USA
| | - Prabhas V Moghe
- Department of Biomedical Engineering, Rutgers University, 599 Taylor Rd., Piscataway, NJ, 08854, USA.
- Department of Chemical and Biochemical Engineering, Rutgers University, 98 Brett Rd., Piscataway, NJ, 08854, USA.
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Implications of fractalkine on glial function, ablation and glial proteins/receptors/markers—understanding its therapeutic usefulness in neurological settings: a narrative review. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2022. [DOI: 10.1186/s43094-022-00446-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
Background
Fractalkine (CX3CL1) is a chemokine predominantly released by neurons. As a signaling molecule, CX3CL1 facilitates talk between neurons and glia. CX3CL1 is considered as a potential target which could alleviate neuroinflammation. However, certain controversial results and ambiguous role of CX3CL1 make it inexorable to decipher the overall effects of CX3CL1 on the physiopathology of glial cells.
Main body of the abstract
Implications of cross-talk between CX3CL1 and different glial proteins/receptors/markers will give a bird eye view of the therapeutic significance of CX3CL1. Keeping with the need, this review identifies the effects of CX3CL1 on glial physiopathology, glial ablation, and gives a wide coverage on the effects of CX3CL1 on certain glial proteins/receptors/markers.
Short conclusion
Pinpoint prediction of the therapeutic effect of CX3CL1 on neuroinflammation needs further research. This is owing to certain obscure roles and implications of CX3CL1 on different glial proteins/receptors/markers, which are crucial under neurological settings. Further challenges are imposed due to the dichotomous roles played by CX3CL1. The age-old chemokine shows many newer scopes of research in near future. Thus, overall assessment of the effect of CX3CL1 becomes crucial prior to its administration in neuroinflammation.
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Gudgeon J, Marín-Rubio JL, Trost M. The role of macrophage scavenger receptor 1 (MSR1) in inflammatory disorders and cancer. Front Immunol 2022; 13:1012002. [PMID: 36325338 PMCID: PMC9618966 DOI: 10.3389/fimmu.2022.1012002] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/28/2022] [Indexed: 08/27/2023] Open
Abstract
Macrophage scavenger receptor 1 (MSR1), also named CD204, holds key inflammatory roles in multiple pathophysiologic processes. Present primarily on the surface of various types of macrophage, this receptor variably affects processes such as atherosclerosis, innate and adaptive immunity, lung and liver disease, and more recently, cancer. As highlighted throughout this review, the role of MSR1 is often dichotomous, being either host protective or detrimental to the pathogenesis of disease. We will discuss the role of MSR1 in health and disease with a focus on the molecular mechanisms influencing MSR1 expression, how altered expression affects disease process and macrophage function, the limited cell signalling pathways discovered thus far, the emerging role of MSR1 in tumour associated macrophages as well as the therapeutic potential of targeting MSR1.
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Affiliation(s)
| | - José Luis Marín-Rubio
- Laboratory for Biological Mass Spectrometry, Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Matthias Trost
- Laboratory for Biological Mass Spectrometry, Biosciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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Zhang G, Wang Z, Hu H, Zhao M, Sun L. Microglia in Alzheimer's Disease: A Target for Therapeutic Intervention. Front Cell Neurosci 2021; 15:749587. [PMID: 34899188 PMCID: PMC8651709 DOI: 10.3389/fncel.2021.749587] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/28/2021] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is one of the most common types of age-related dementia worldwide. In addition to extracellular amyloid plaques and intracellular neurofibrillary tangles, dysregulated microglia also play deleterious roles in the AD pathogenesis. Numerous studies have demonstrated that unbridled microglial activity induces a chronic neuroinflammatory environment, promotes β-amyloid accumulation and tau pathology, and impairs microglia-associated mitophagy. Thus, targeting microglia may pave the way for new therapeutic interventions. This review provides a thorough overview of the pathophysiological role of the microglia in AD and illustrates the potential avenues for microglia-targeted therapies, including microglial modification, immunoreceptors, and anti-inflammatory drugs.
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Affiliation(s)
- Guimei Zhang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Zicheng Wang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Huiling Hu
- Department of Intensive Care Unit, The Affiliated Hospital of Qingdao University, Shandong, China
| | - Meng Zhao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Jilin University, Changchun, China
| | - Li Sun
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Jilin University, Changchun, China
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7
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Li B, Chen M, Aguzzi A, Zhu C. The role of macrophage scavenger receptor 1 (Msr1) in prion pathogenesis. J Mol Med (Berl) 2021; 99:877-887. [PMID: 33758958 PMCID: PMC8164582 DOI: 10.1007/s00109-021-02061-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/01/2021] [Accepted: 03/07/2021] [Indexed: 11/01/2022]
Abstract
The progression of prion diseases is accompanied by the accumulation of prions in the brain. Ablation of microglia enhances prion accumulation and accelerates disease progression, suggesting that microglia play a neuroprotective role by clearing prions. However, the mechanisms underlying the phagocytosis and clearance of prion are largely unknown. The macrophage scavenger receptor 1 (Msr1) is an important phagocytic receptor expressed by microglia in the brain and is involved in the uptake and clearance of soluble amyloid-β. We therefore asked whether Msr1 might play a role in prion clearance and assessed the scavenger function of Msr1 in prion pathogenesis. We found that Msr1 expression was upregulated in prion-infected mouse brains. However, Msr1 deficiency did not change prion disease progression or lesion patterns. Prion deposition in Msr1 deficient mice was similar to their wild-type littermates. In addition, prion-induced neuroinflammation was not affected by Msr1 ablation. We conclude that Msr1 does not play a major role in prion pathogenesis. KEY MESSAGES: Msr1 expression is upregulated in prion-infected mouse brains at the terminal stage Msr1 deficiency does not affect prion disease progression Msr1 does not play a major role in prion clearance or prion pathogenesis Microglia-mediated phagocytosis and clearance of Aβ and prion may adopt distinct molecular pathways.
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Affiliation(s)
- Bei Li
- School of Basic Medical Sciences, Fudan University, Dong'An Road 130, Shanghai, 200032, China
| | - Meiling Chen
- School of Basic Medical Sciences, Fudan University, Dong'An Road 130, Shanghai, 200032, China
| | - Adriano Aguzzi
- Institute of Neuropathology, University Hospital Zurich, Schmelzbergstrasse 12, CH-8091, Zurich, Switzerland.
| | - Caihong Zhu
- School of Basic Medical Sciences, Fudan University, Dong'An Road 130, Shanghai, 200032, China.
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Eshraghi M, Adlimoghaddam A, Mahmoodzadeh A, Sharifzad F, Yasavoli-Sharahi H, Lorzadeh S, Albensi BC, Ghavami S. Alzheimer's Disease Pathogenesis: Role of Autophagy and Mitophagy Focusing in Microglia. Int J Mol Sci 2021; 22:3330. [PMID: 33805142 PMCID: PMC8036323 DOI: 10.3390/ijms22073330] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/14/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is a debilitating neurological disorder, and currently, there is no cure for it. Several pathologic alterations have been described in the brain of AD patients, but the ultimate causative mechanisms of AD are still elusive. The classic hallmarks of AD, including amyloid plaques (Aβ) and tau tangles (tau), are the most studied features of AD. Unfortunately, all the efforts targeting these pathologies have failed to show the desired efficacy in AD patients so far. Neuroinflammation and impaired autophagy are two other main known pathologies in AD. It has been reported that these pathologies exist in AD brain long before the emergence of any clinical manifestation of AD. Microglia are the main inflammatory cells in the brain and are considered by many researchers as the next hope for finding a viable therapeutic target in AD. Interestingly, it appears that the autophagy and mitophagy are also changed in these cells in AD. Inside the cells, autophagy and inflammation interact in a bidirectional manner. In the current review, we briefly discussed an overview on autophagy and mitophagy in AD and then provided a comprehensive discussion on the role of these pathways in microglia and their involvement in AD pathogenesis.
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Affiliation(s)
- Mehdi Eshraghi
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA;
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Aida Adlimoghaddam
- St. Boniface Hospital Albrechtsen Research Centre, Division of Neurodegenerative Disorders, Winnipeg, MB R2H2A6, Canada; (A.A.); (B.C.A.)
| | - Amir Mahmoodzadeh
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran;
| | - Farzaneh Sharifzad
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; (F.S.); (H.Y.-S.)
| | - Hamed Yasavoli-Sharahi
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; (F.S.); (H.Y.-S.)
| | - Shahrokh Lorzadeh
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
| | - Benedict C. Albensi
- St. Boniface Hospital Albrechtsen Research Centre, Division of Neurodegenerative Disorders, Winnipeg, MB R2H2A6, Canada; (A.A.); (B.C.A.)
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada;
- Research Institute of Oncology and Hematology, Cancer Care Manitoba-University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Biology of Breathing Theme, Children Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
- Faculty of Medicine, Katowice School of Technology, 40-555 Katowice, Poland
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Shin JW, Lee JC. Roles of microglial membranes in Alzheimer's disease. CURRENT TOPICS IN MEMBRANES 2020; 86:301-314. [PMID: 33837697 PMCID: PMC8082413 DOI: 10.1016/bs.ctm.2020.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The majority of Alzheimer's disease (AD) risk genes are highly and selectively expressed by microglia in the brain. Several of these genes are related to lipid and cholesterol metabolism, lipid synthesis, lipid transport, endocytosis, exocytosis and phagocytosis. Therefore, studying the roles of cellular membrane biophysics in microglial function should improve our understanding of the AD pathology. In this chapter, we discuss how lipid rafts and membrane-cytoskeleton adhesion impact microglial-mediated oxidative stress and clearance of amyloid-β peptide (Aβ). We also discuss potential roles of lipid membrane-bound extracellular vesicles as carriers of pathological factors to promote inflammation and cytotoxicity.
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Affiliation(s)
- Jae-Won Shin
- Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States; Department of Pharmacology, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States
| | - James C Lee
- Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, United States.
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10
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Sandoval K, Umbaugh D, House A, Crider A, Witt K. Somatostatin Receptor Subtype-4 Regulates mRNA Expression of Amyloid-Beta Degrading Enzymes and Microglia Mediators of Phagocytosis in Brains of 3xTg-AD Mice. Neurochem Res 2019; 44:2670-2680. [PMID: 31630317 DOI: 10.1007/s11064-019-02890-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/06/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in memory and cognitive impairment. The use of somatostatin receptor subtype-4 (SSTR4) agonists have been proposed for AD treatment. This study investigated the effects of selective SSTR4 agonist NNC 26-9100 on mRNA expression of key genes associated with AD pathology (microglia mediators of Aβ phagocytosis, amyloid-beta (Aβ)-degrading enzymes, anti-oxidant enzymes and pro-inflammatory cytokines) in 3xTg-AD mice. Mice were administered NNC 26-9100 (0.2 µg, i.c.v.) or vehicle control, with cortical and subcortical brain tissue collected at 6 h and 24 h post-treatment. At 6 h, NNC 26-9100 treatment decreased cortical expression of cluster of differentiation-33 (Cd33) by 25%, while increasing cortical and subcortical macrophage scavenger receptor-1 (Msr1) by 1.8 and 2.0-fold, respectively. The Cd33 downregulation and Msr1 upregulation support a state of microglia associated Aβ phagocytosis. At 24 h, NNC 26-9100 treatment increased the cortical expression of Sstr4 (4.9-fold), Aβ-degrading enzymes neprilysin (9.3-fold) and insulin degrading enzyme (14.8-fold), and the antioxidant catalase (3.6-fold). Similar effects at 24 h were found in subcortical tissue with NNC 26-9100 treatment, but did not reach statistical significance. No changes in pro-inflammatory cytokine expression were found. These data demonstrated NNC 26-9100 facilitates transcriptional changes in brain tissue identified with Aβ phagocytosis and clearance, further supporting SSTR4 as a treatment target for AD.
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Affiliation(s)
- Karin Sandoval
- Department of Pharmaceutical Sciences Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, 200 University Park Drive., Building 220, Edwardsville, IL, 62025, USA
| | - David Umbaugh
- Department of Pharmaceutical Sciences Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, 200 University Park Drive., Building 220, Edwardsville, IL, 62025, USA
| | - Austin House
- Department of Pharmaceutical Sciences Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, 200 University Park Drive., Building 220, Edwardsville, IL, 62025, USA
| | - Albert Crider
- Department of Pharmaceutical Sciences Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, 200 University Park Drive., Building 220, Edwardsville, IL, 62025, USA
| | - Ken Witt
- Department of Pharmaceutical Sciences Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, 200 University Park Drive., Building 220, Edwardsville, IL, 62025, USA.
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11
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Scavenger Receptor-A deficiency impairs immune response of microglia and astrocytes potentiating Alzheimer's disease pathophysiology. Brain Behav Immun 2018; 69:336-350. [PMID: 29246456 DOI: 10.1016/j.bbi.2017.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/04/2017] [Accepted: 12/11/2017] [Indexed: 12/25/2022] Open
Abstract
Late onset Alzheimer disease's (LOAD) main risk factor is aging. Although it is not well known which age-related factors are involved in its development, evidence points out to the involvement of an impaired amyloid-β (Aβ) clearance in the aged brain among possible causes. Glial cells are the main scavengers of the brain, where Scavenger Receptor class A (SR-A) emerges as a relevant player in AD because of its participation in Aβ uptake and in the modulation of glial cell inflammatory response. Here, we show that SR-A expression is reduced in the hippocampus of aged animals and APP/PS1 mice. Given that Aβ deposition increases in the aging brain, we generated a triple transgenic mouse, which accumulates Aβ and is knockout for SR-A (APP/PS1/SR-A-/-) to evaluate Aβ accumulation and the inflammatory outcome of SR-A depletion in the aged brain. The lifespan of APP/PS1/SR-A-/- mice was greatly reduced, accompanied by a 3-fold increase in plasmatic pro-inflammatory cytokines, and reduced performance in a working memory behavioral assessment. Microglia and astrocytes lacking SR-A displayed impaired oxidative response and nitric oxide production, produced up to 7-fold more pro-inflammatory cytokines and showed a 12-fold reduction in anti-inflammatory cytokines release, with conspicuous changes in lipopolysaccharide-induced glial activation. Isolated microglia from young and adult mice lacking SR-A showed a 50% reduction in phagocytic activity. Our results indicate that reduced expression of SR-A can deregulate glial inflammatory response and potentiate Aβ accumulation, two mechanisms that could contribute to AD progression.
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12
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Sun BL, Wang LH, Yang T, Sun JY, Mao LL, Yang MF, Yuan H, Colvin RA, Yang XY. Lymphatic drainage system of the brain: A novel target for intervention of neurological diseases. Prog Neurobiol 2017; 163-164:118-143. [PMID: 28903061 DOI: 10.1016/j.pneurobio.2017.08.007] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 08/11/2017] [Accepted: 08/31/2017] [Indexed: 12/20/2022]
Abstract
The belief that the vertebrate brain functions normally without classical lymphatic drainage vessels has been held for many decades. On the contrary, new findings show that functional lymphatic drainage does exist in the brain. The brain lymphatic drainage system is composed of basement membrane-based perivascular pathway, a brain-wide glymphatic pathway, and cerebrospinal fluid (CSF) drainage routes including sinus-associated meningeal lymphatic vessels and olfactory/cervical lymphatic routes. The brain lymphatic systems function physiological as a route of drainage for interstitial fluid (ISF) from brain parenchyma to nearby lymph nodes. Brain lymphatic drainage helps maintain water and ion balance of the ISF, waste clearance, and reabsorption of macromolecular solutes. A second physiological function includes communication with the immune system modulating immune surveillance and responses of the brain. These physiological functions are influenced by aging, genetic phenotypes, sleep-wake cycle, and body posture. The impairment and dysfunction of the brain lymphatic system has crucial roles in age-related changes of brain function and the pathogenesis of neurovascular, neurodegenerative, and neuroinflammatory diseases, as well as brain injury and tumors. In this review, we summarize the key component elements (regions, cells, and water transporters) of the brain lymphatic system and their regulators as potential therapeutic targets in the treatment of neurologic diseases and their resulting complications. Finally, we highlight the clinical importance of ependymal route-based targeted gene therapy and intranasal drug administration in the brain by taking advantage of the unique role played by brain lymphatic pathways in the regulation of CSF flow and ISF/CSF exchange.
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Affiliation(s)
- Bao-Liang Sun
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China.
| | - Li-Hua Wang
- Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, China
| | - Tuo Yang
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jing-Yi Sun
- Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Gangwon 220-701, Republic of Korea
| | - Lei-Lei Mao
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Ming-Feng Yang
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Hui Yuan
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Robert A Colvin
- Department of Biological Sciences, Interdisciplinary Graduate Program in Molecular and Cellular Biology, Neuroscience Program, Ohio University, Athens, OH 45701, USA
| | - Xiao-Yi Yang
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China.
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Zuroff L, Daley D, Black KL, Koronyo-Hamaoui M. Clearance of cerebral Aβ in Alzheimer's disease: reassessing the role of microglia and monocytes. Cell Mol Life Sci 2017; 74:2167-2201. [PMID: 28197669 PMCID: PMC5425508 DOI: 10.1007/s00018-017-2463-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 01/07/2017] [Accepted: 01/11/2017] [Indexed: 01/03/2023]
Abstract
Deficiency in cerebral amyloid β-protein (Aβ) clearance is implicated in the pathogenesis of the common late-onset forms of Alzheimer’s disease (AD). Accumulation of misfolded Aβ in the brain is believed to be a net result of imbalance between its production and removal. This in turn may trigger neuroinflammation, progressive synaptic loss, and ultimately cognitive decline. Clearance of cerebral Aβ is a complex process mediated by various systems and cell types, including vascular transport across the blood–brain barrier, glymphatic drainage, and engulfment and degradation by resident microglia and infiltrating innate immune cells. Recent studies have highlighted a new, unexpected role for peripheral monocytes and macrophages in restricting cerebral Aβ fibrils, and possibly soluble oligomers. In AD transgenic (ADtg) mice, monocyte ablation or inhibition of their migration into the brain exacerbated Aβ pathology, while blood enrichment with monocytes and their increased recruitment to plaque lesion sites greatly diminished Aβ burden. Profound neuroprotective effects in ADtg mice were further achieved through increased cerebral recruitment of myelomonocytes overexpressing Aβ-degrading enzymes. This review summarizes the literature on cellular and molecular mechanisms of cerebral Aβ clearance with an emphasis on the role of peripheral monocytes and macrophages in Aβ removal.
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Affiliation(s)
- Leah Zuroff
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, 127 S. San Vicente, AHSP A8115, Los Angeles, CA, 90048, USA.,Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - David Daley
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, 127 S. San Vicente, AHSP A8115, Los Angeles, CA, 90048, USA
| | - Keith L Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, 127 S. San Vicente, AHSP A8115, Los Angeles, CA, 90048, USA
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Institute, Cedars-Sinai Medical Center, 127 S. San Vicente, AHSP A8115, Los Angeles, CA, 90048, USA. .,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA.
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14
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von Bernhardi R, Cornejo F, Parada GE, Eugenín J. Role of TGFβ signaling in the pathogenesis of Alzheimer's disease. Front Cell Neurosci 2015; 9:426. [PMID: 26578886 PMCID: PMC4623426 DOI: 10.3389/fncel.2015.00426] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 10/09/2015] [Indexed: 12/19/2022] Open
Abstract
Aging is the main risk factor for Alzheimer’s disease (AD); being associated with conspicuous changes on microglia activation. Aged microglia exhibit an increased expression of cytokines, exacerbated reactivity to various stimuli, oxidative stress, and reduced phagocytosis of β-amyloid (Aβ). Whereas normal inflammation is protective, it becomes dysregulated in the presence of a persistent stimulus, or in the context of an inflammatory environment, as observed in aging. Thus, neuroinflammation can be a self-perpetuating deleterious response, becoming a source of additional injury to host cells in neurodegenerative diseases. In aged individuals, although transforming growth factor β (TGFβ) is upregulated, its canonical Smad3 signaling is greatly reduced and neuroinflammation persists. This age-related Smad3 impairment reduces protective activation while facilitating cytotoxic activation of microglia through several cellular mechanisms, potentiating microglia-mediated neurodegeneration. Here, we critically discuss the role of TGFβ-Smad signaling on the cytotoxic activation of microglia and its relevance in the pathogenesis of AD. Other protective functions, such as phagocytosis, although observed in aged animals, are not further induced by inflammatory stimuli and TGFβ1. Analysis in silico revealed that increased expression of receptor scavenger receptor (SR)-A, involved in Aβ uptake and cell activation, by microglia exposed to TGFβ, through a Smad3-dependent mechanism could be mediated by transcriptional co-factors Smad2/3 over the MSR1 gene. We discuss that changes of TGFβ-mediated regulation could at least partially mediate age-associated microglia changes, and, together with other changes on inflammatory response, could result in the reduction of protective activation and the potentiation of cytotoxicity of microglia, resulting in the promotion of neurodegenerative diseases.
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Affiliation(s)
- Rommy von Bernhardi
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Francisca Cornejo
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Guillermo E Parada
- Laboratory of Neuroscience, Faculty of Medicine, Department of Neurology, Pontificia Universidad Católica de Chile Santiago, Chile
| | - Jaime Eugenín
- Laboratory of Neural Systems, Faculty of Chemistry and Biology, Department of Biology, Universidad de Santiago de Chile Santiago, Chile
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Abstract
Alzheimer's disease (AD) is typified by a robust microglial-mediated inflammatory response within the brain. Indeed, microglial accumulation around plaques in AD is one of the classical hallmarks of the disease pathology. Although microglia have the capacity to remove β-amyloid deposits and alleviate disease pathology, they fail to do so. Instead, they become chronically activated and promote inflammation-mediated impairment of cognition and cytotoxicity. However, if microglial function could be altered to engage their phagocytic response, promote their tissue maintenance functions, and prevent release of factors that promote tissue damage, this could provide therapeutic benefit. This review is focused on the current knowledge of microglial homeostatic mechanisms in AD, and mechanisms involved in the regulation of microglial phenotype in this context.
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Affiliation(s)
- Tarja M Malm
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland,
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16
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Microglia as a critical player in both developmental and late-life CNS pathologies. Acta Neuropathol 2014; 128:333-45. [PMID: 25056803 PMCID: PMC4131160 DOI: 10.1007/s00401-014-1321-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/17/2014] [Accepted: 07/01/2014] [Indexed: 02/04/2023]
Abstract
Microglia, the tissue-resident macrophages of the brain, are attracting increasing attention as key players in brain homeostasis from development through aging. Recent works have highlighted new and unexpected roles for these once-enigmatic cells in both healthy central nervous system function and in diverse pathologies long thought to be primarily the result of neuronal malfunction. In this review, we have chosen to focus on Rett syndrome, which features early neurodevelopmental pathology, and Alzheimer’s disease, a disorder associated predominantly with aging. Interestingly, receptor-mediated microglial phagocytosis has emerged as a key function in both developmental and late-life brain pathologies. In a mouse model of Rett syndrome, bone marrow transplant and CNS engraftment of microglia-like cells were associated with surprising improvements in pathology—these benefits were abrogated by block of phagocytic function. In Alzheimer’s disease, large-scale genome-wide association studies have been brought to bear as a method of identifying previously unknown susceptibility genes, which highlight microglial receptors as promising novel targets for therapeutic modulation. Multi-photon in vivo microscopy has provided a method of directly visualizing the effects of manipulation of these target genes. Here, we review the latest findings and concepts emerging from the rapidly growing body of literature exemplified for Rett syndrome and late-onset, sporadic Alzheimer’s disease.
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Yu Y, Ye RD. Microglial Aβ receptors in Alzheimer's disease. Cell Mol Neurobiol 2014; 35:71-83. [PMID: 25149075 DOI: 10.1007/s10571-014-0101-6] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
Abstract
Amyloid β (Aβ) plays a pivotal role in the progression of Alzheimer's disease (AD) through its neurotoxic and inflammatory effects. On one hand, Aβ binds to microglia and activates them to produce inflammatory mediators. On the other hand, Aβ is cleared by microglia through receptor-mediated phagocytosis and degradation. This review focuses on microglial membrane receptors that bind Aβ and contribute to microglial activation and/or Aβ phagocytosis and clearance. These receptors can be categorized into several groups. The scavenger receptors (SRs) include scavenger receptor A-1 (SCARA-1), MARCO, scavenger receptor B-1 (SCARB-1), CD36 and the receptor for advanced glycation end product (RAGE). The G protein-coupled receptors (GPCRs) are formyl peptide receptor 2 (FPR2) and chemokine-like receptor 1 (CMKLR1). There are also toll-like receptors (TLRs) including TLR2, TLR4, and the co-receptor CD14. Functionally, SCARA-1 and CMKLR1 are involved in the uptake of Aβ, and RAGE is responsible for the activation of microglia and production of proinflammatory mediators following Aβ binding. CD36, CD36/CD47/α6β1-intergrin, CD14/TLR2/TLR4, and FPR2 display both functions. Additionally, MARCO and SCARB-1 also exhibit the ability to bind Aβ and may be involved in the progression of AD. Here, we focus on the expression and distribution of these receptors in microglia and their roles in microglia interaction with Aβ. Finally, we discuss the potential therapeutic value of these receptors in AD.
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Affiliation(s)
- Yang Yu
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China,
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18
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Guillot-Sestier MV, Town T. Innate immunity in Alzheimer's disease: a complex affair. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2014; 12:593-607. [PMID: 23574177 DOI: 10.2174/1871527311312050008] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by three major histopathological hallmarks: β-amyloid deposits, neurofibrillary tangles and gliosis. While neglected for decades, the neuroinflammatory processes coordinated by microglia are now accepted as etiologic events in AD evolution. Microglial cells are found in close vicinity to amyloid plaques and display various activation phenotypes determined by the expression of a wide range of cytokines, chemokines, and innate immune surface receptors. During the development of AD pathology, microglia fail to restrict amyloid plaques and may contribute to neurotoxicity and cognitive deficit. Nevertheless, under specific activation states, microglia can participate in cerebral amyloid clearance. This review focuses on the complex relationship between microglia and Aβ pathology, and highlights both deleterious and beneficial roles of microglial activation states in the context of AD. A deeper understanding of microglial biology will hopefully pave the way for next-generation AD therapeutic approaches aimed at harnessing these enigmatic innate immune cells of the central nervous system.
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Affiliation(s)
- Marie-Victoire Guillot-Sestier
- Regenerative Medicine Institute Neural Program, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Steven Spielberg Building Room 345, Los Angeles, CA 90048, USA
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19
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Cai Z, Hussain MD, Yan LJ. Microglia, neuroinflammation, and beta-amyloid protein in Alzheimer's disease. Int J Neurosci 2013; 124:307-21. [DOI: 10.3109/00207454.2013.833510] [Citation(s) in RCA: 320] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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20
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Zotova E, Bharambe V, Cheaveau M, Morgan W, Holmes C, Harris S, Neal JW, Love S, Nicoll JAR, Boche D. Inflammatory components in human Alzheimer's disease and after active amyloid-β42 immunization. ACTA ACUST UNITED AC 2013; 136:2677-96. [PMID: 23943781 DOI: 10.1093/brain/awt210] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Inflammatory processes are important in the pathogenesis of Alzheimer's disease and in response to amyloid-β immunotherapy. We investigated the expression of multiple inflammatory markers in the brains of 28 non-immunized patients with Alzheimer's disease and 11 patients with Alzheimer's disease immunized against amyloid-β42 (AN1792): microglial ionized calcium-binding adaptor Iba-1, lysosome marker CD68, macrophage scavenger receptor A, Fcγ receptors I (CD64) and II (CD32); and also immunoglobulin IgG, complement C1q and the T lymphocyte marker CD3 using immunohistochemistry. The data were analysed with regard to amyloid-β and phospho-tau pathology, severity of cerebral amyloid angiopathy and cortical microhaemorrhages. In non-immunized Alzheimer's disease cases, amyloid-β42 correlated inversely with CD32 and Iba-1, whereas phospho-tau correlated directly with all microglial markers, IgG, C1q and the number of T cells. In immunized Alzheimer's disease cases, amyloid-β42 load correlated directly with macrophage scavenger receptor A-positive clusters and inversely with C1q. The severity of cerebral amyloid angiopathy and microhaemorrhages did not relate to any of the analysed markers. Overall, the levels of CD68, macrophage scavenger receptor A, CD64, CD32 and the number of macrophage scavenger receptor A-positive plaque-related clusters were significantly lower in immunized than non-immunized cases, although there was no significant difference in Iba-1 load, number of Iba-1-positive cells, IgG load, C1q load or number of T cells. Our findings indicate that different microglial populations co-exist in the Alzheimer's disease brain, and that the local inflammatory status within the grey matter is importantly linked with tau pathology. After amyloid-β immunization, the microglial functional state is altered in association with reduced amyloid-β and tau pathology. The results suggest that, in the long term, amyloid-β immunotherapy results in downregulation of microglial activation and potentially reduces the inflammation-mediated component of the neurodegeneration of Alzheimer's disease.
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Affiliation(s)
- Elina Zotova
- Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Mailpoint 806, Southampton General Hospital, Southampton SO16 6YD, UK
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Canton J, Neculai D, Grinstein S. Scavenger receptors in homeostasis and immunity. Nat Rev Immunol 2013; 13:621-34. [PMID: 23928573 DOI: 10.1038/nri3515] [Citation(s) in RCA: 563] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Scavenger receptors were originally identified by their ability to recognize and to remove modified lipoproteins; however, it is now appreciated that they carry out a striking range of functions, including pathogen clearance, lipid transport, the transport of cargo within the cell and even functioning as taste receptors. The large repertoire of ligands recognized by scavenger receptors and their broad range of functions are not only due to the wide range of receptors that constitute this family but also to their ability to partner with various co-receptors. The ability of individual scavenger receptors to associate with different co-receptors makes their responsiveness extremely versatile. This Review highlights recent insights into the structural features that determine the function of scavenger receptors and the emerging role that these receptors have in immune responses, notably in macrophage polarization and in the pathogenesis of diseases such as atherosclerosis and Alzheimer's disease.
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Affiliation(s)
- Johnathan Canton
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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22
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Cornejo F, von Bernhardi R. Role of scavenger receptors in glia-mediated neuroinflammatory response associated with Alzheimer's disease. Mediators Inflamm 2013; 2013:895651. [PMID: 23737655 PMCID: PMC3662199 DOI: 10.1155/2013/895651] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/15/2013] [Indexed: 12/15/2022] Open
Abstract
It is widely accepted that cells serving immune functions in the brain, namely, microglia and astrocytes, are important mediators of pathological phenomena observed in Alzheimer's disease. However, it is unknown how these cells initiate the response that results in cognitive impairment and neuronal degeneration. Here, we review the participation of the immune response mediated by glial cells in Alzheimer's disease and the role played by scavenger receptors in the development of this pathology, focusing on the relevance of class A scavenger receptor (SR-A) for A β clearance and inflammatory activation of glial cell, and as a potential target for Alzheimer's disease therapy.
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Affiliation(s)
- Francisca Cornejo
- Laboratorio de Neurociencias, Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta, 391 Santiago, Chile
| | - Rommy von Bernhardi
- Laboratorio de Neurociencias, Departamento de Neurología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Marcoleta, 391 Santiago, Chile
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23
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Jonsdottir G, Ingolfsdottir IE, Thormodsson FR, Petersen PH. Endogenous aggregates of amyloidogenic cystatin C variant are removed by THP-1 cells in vitro and induce differentiation and a proinflammatory response. Neurobiol Aging 2013; 34:1389-96. [DOI: 10.1016/j.neurobiolaging.2012.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 11/05/2012] [Accepted: 11/22/2012] [Indexed: 12/16/2022]
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Scavenger receptor A deficiency accelerates cerebrovascular amyloidosis in an animal model. J Mol Neurosci 2012; 50:198-203. [PMID: 23108486 DOI: 10.1007/s12031-012-9909-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Accepted: 10/16/2012] [Indexed: 01/22/2023]
Abstract
Cerebrovascular amyloidosis caused by amyloid accumulation in blood vessel walls may lead to hemorrhagic stroke and cognitive impairment. Expression of TGF-β1 under glial fibrillary acidic protein promoter in mice leads to age-related deposition of amyloid, including β-amyloid (Aβ), around cerebral blood vessels, leading to vascular pathology starting at age of 7 months. We have recently shown the important role of macrophages in clearing cerebrovascular amyloid. Scavenger receptor A (SRA) is a multi-ligand and multifunctional receptor expressed on macrophages, and it has been suggested to play a role in meditating phagocytosis of different types of antigens. We investigated the role of SRA in mediating cerebrovascular amyloid clearance. We bred TGF-β1 mice with SRA(-/-) mice and discovered that TGF-β1/SRA(-/-) mice showed cerebrovascular pathology at an earlier age (3 months) compared with TGF-β1 mice. Furthermore, SRA deficiency in macrophages led to impaired clearing of congophilic cerebrovascular amyloid from amyloid precursor protein mouse model and led to reduced phagocytosis of both soluble and insoluble Aβ in vivo as compared with macrophages from wild-type mice. Our findings demonstrate the important role of SRA in cerebrovascular amyloid pathology and suggest targeting SRA for future diagnostic and therapeutic approaches for cerebral amyloid angiopathy.
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Microglial scavenger receptors and their roles in the pathogenesis of Alzheimer's disease. Int J Alzheimers Dis 2012; 2012:489456. [PMID: 22666621 PMCID: PMC3362056 DOI: 10.1155/2012/489456] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/19/2012] [Indexed: 01/13/2023] Open
Abstract
Alzheimer's disease (AD) is increasing in prevalence with the aging population. Deposition of amyloid-β (Aβ) in the brain of AD patients is a hallmark of the disease and is associated with increased microglial numbers and activation state. The interaction of microglia with Aβ appears to play a dichotomous role in AD pathogenesis. On one hand, microglia can phagocytose and clear Aβ, but binding of microglia to Aβ also increases their ability to produce inflammatory cytokines, chemokines, and neurotoxic reactive oxygen species (ROS). Scavenger receptors, a group of evolutionally conserved proteins expressed on the surface of microglia act as receptors for Aβ. Of particular interest are SCARA-1 (scavenger receptor A-1), CD36, and RAGE (receptor for advanced glycation end products). SCARA-1 appears to be involved in the clearance of Aβ, while CD36 and RAGE are involved in activation of microglia by Aβ. In this review, we discuss the roles of various scavenger receptors in the interaction of microglia with Aβ and propose that these receptors play complementary, nonredundant functions in the development of AD pathology. We also discuss potential therapeutic applications for these receptors in AD.
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Njie EG, Boelen E, Stassen FR, Steinbusch HWM, Borchelt DR, Streit WJ. Ex vivo cultures of microglia from young and aged rodent brain reveal age-related changes in microglial function. Neurobiol Aging 2010; 33:195.e1-12. [PMID: 20580465 DOI: 10.1016/j.neurobiolaging.2010.05.008] [Citation(s) in RCA: 226] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 05/01/2010] [Accepted: 05/10/2010] [Indexed: 11/26/2022]
Abstract
To understand how microglial cell function may change with aging, various protocols have been developed to isolate microglia from the young and aged central nervous system (CNS). Here we report modification of an existing protocol that is marked by less debris contamination and improved yields and demonstrate that microglial functions are varied and dependent on age. Specifically, we found that microglia from aged mice constitutively secrete greater amounts of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) relative to microglia from younger mice and are less responsive to stimulation. Also, microglia from aged mice have reduced glutathione levels and internalize less amyloid beta peptide (Aβ) while microglia from mice of all ages do not retain the amyloid beta peptide for a significant length of time. These studies offer further support for the idea that microglial cell function changes with aging. They suggest that microglial Aβ phagocytosis results in Aβ redistribution rather than biophysical degradation in vivo and thereby provide mechanistic insight to the lack of amyloid burden elimination by parenchymal microglia in aged adults and those suffering from Alzheimer's disease.
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Affiliation(s)
- Emalick G Njie
- Department of Neuroscience, University of Florida College of Medicine and McKnight Brain Institute, Gainesville, FL 32610-0244, United States.
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Town T, Nikolic V, Tan J. The microglial "activation" continuum: from innate to adaptive responses. J Neuroinflammation 2005; 2:24. [PMID: 16259628 PMCID: PMC1298325 DOI: 10.1186/1742-2094-2-24] [Citation(s) in RCA: 329] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Accepted: 10/31/2005] [Indexed: 12/25/2022] Open
Abstract
Microglia are innate immune cells of myeloid origin that take up residence in the central nervous system (CNS) during embryogenesis. While classically regarded as macrophage-like cells, it is becoming increasingly clear that reactive microglia play more diverse roles in the CNS. Microglial "activation" is often used to refer to a single phenotype; however, in this review we consider that a continuum of microglial activation exists, with phagocytic response (innate activation) at one end and antigen presenting cell function (adaptive activation) at the other. Where activated microglia fall in this spectrum seems to be highly dependent on the type of stimulation provided. We begin by addressing the classical roles of peripheral innate immune cells including macrophages and dendritic cells, which seem to define the edges of this continuum. We then discuss various types of microglial stimulation, including Toll-like receptor engagement by pathogen-associated molecular patterns, microglial challenge with myelin epitopes or Alzheimer's β-amyloid in the presence or absence of CD40L co-stimulation, and Alzheimer disease "immunotherapy". Based on the wide spectrum of stimulus-specific microglial responses, we interpret these cells as immune cells that demonstrate remarkable plasticity following activation. This interpretation has relevance for neurodegenerative/neuroinflammatory diseases where reactive microglia play an etiological role; in particular viral/bacterial encephalitis, multiple sclerosis and Alzheimer disease.
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Affiliation(s)
- Terrence Town
- Section of Immunobiology, Yale University School of Medicine, 300 Cedar St., New Haven, CT 06520-8011, USA
- Neuroimmunology Laboratory, Silver Child Development Center, Department of Psychiatry and Behavioral Medicine, University of South Florida, 3515 E. Fletcher Ave., Tampa, FL 33613, USA
| | - Veljko Nikolic
- Neuroimmunology Laboratory, Silver Child Development Center, Department of Psychiatry and Behavioral Medicine, University of South Florida, 3515 E. Fletcher Ave., Tampa, FL 33613, USA
| | - Jun Tan
- Neuroimmunology Laboratory, Silver Child Development Center, Department of Psychiatry and Behavioral Medicine, University of South Florida, 3515 E. Fletcher Ave., Tampa, FL 33613, USA
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28
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Koenigsknecht J, Landreth G. Microglial phagocytosis of fibrillar beta-amyloid through a beta1 integrin-dependent mechanism. J Neurosci 2005; 24:9838-46. [PMID: 15525768 PMCID: PMC6730228 DOI: 10.1523/jneurosci.2557-04.2004] [Citation(s) in RCA: 331] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Microglia are the principle immune effector and phagocytic cells in the CNS. These cells are associated with fibrillar beta-amyloid (fAbeta)-containing plaques found in the brains of Alzheimer's disease (AD) patients. The plaque-associated microglia undergo a phenotypic conversion into an activated phenotype and are responsible for the development of a focal inflammatory response that exacerbates and accelerates the disease process. Paradoxically, despite the presence of abundant activated microglia in the brain of AD patients, these cells fail to mount a phagocytic response to Abeta deposits but can efficiently phagocytose Abeta fibrils and plaques in vitro. We report that exposure of microglia to fAbeta in vitro induces phagocytosis through mechanisms distinct from those used by the classical phagocytic receptors, the Ig receptors (FcRgammaI and FcgammaRIII) or complement receptors. Microglia interact with fAbeta through a recently characterized Abeta cell surface receptor complex comprising the B-class scavenger receptor CD36, alpha6beta1 integrin, and CD47 (integrin-associated protein). Antagonists specific for each component of the receptor complex blocks fAbeta-stimulated phagocytosis. These data demonstrated that engagement of this ensemble of receptors is required for induction of phagocytosis. The phagocytic response stimulated by this receptor complex is driven principally by a beta(1) integrin-linked process that is morphologically and mechanistically distinct from the classical type I and type II phagocytic mechanisms. These data provide evidence for phagocytic uptake of fAbeta through a receptor-mediated, nonclassical phagocytic mechanism.
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Affiliation(s)
- Jessica Koenigsknecht
- Alzheimer Research Laboratory, Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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Kunjathoor VV, Tseng AA, Medeiros LA, Khan T, Moore KJ. beta-Amyloid promotes accumulation of lipid peroxides by inhibiting CD36-mediated clearance of oxidized lipoproteins. J Neuroinflammation 2004; 1:23. [PMID: 15546489 PMCID: PMC535814 DOI: 10.1186/1742-2094-1-23] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Accepted: 11/16/2004] [Indexed: 01/10/2023] Open
Abstract
Background Recent studies suggest that hypercholesterolemia, an established risk factor for atherosclerosis, is also a risk factor for Alzheimer's disease. The myeloid scavenger receptor CD36 binds oxidized lipoproteins that accumulate with hypercholesterolemia and mediates their clearance from the circulation and peripheral tissues. Recently, we demonstrated that CD36 also binds fibrillar β-amyloid and initiates a signaling cascade that regulates microglial recruitment and activation. As increased lipoprotein oxidation and accumulation of lipid peroxidation products have been reported in Alzheimer's disease, we investigated whether β-amyloid altered oxidized lipoprotein clearance via CD36. Methods The availability of mice genetically deficient in class A (SRAI & II) and class B (CD36) scavenger receptors has facilitated studies to discriminate their individual actions. Using primary microglia and macrophages, we assessed the impact of Aβ on: (a) cholesterol ester accumulation by GC-MS and neutral lipid staining, (b) binding, uptake and degradation of 125I-labeled oxidized lipoproteins via CD36, SR-A and CD36/SR-A-independent pathways, (c) expression of SR-A and CD36. In addition, using mice with targeted deletions in essential kinases in the CD36-signaling cascade, we investigated whether Aβ-CD36 signaling altered metabolism of oxidized lipoproteins. Results In primary microglia and macrophages, Aβ inhibited binding, uptake and degradation of oxidized low density lipoprotein (oxLDL) in a dose-dependent manner. While untreated cells accumulated abundant cholesterol ester in the presence of oxLDL, cells treated with Aβ were devoid of cholesterol ester. Pretreatment of cells with Aβ did not affect subsequent degradation of oxidized lipoproteins, indicating that lysosomal accumulation of Aβ did not disrupt this degradation pathway. Using mice with targeted deletions of the scavenger receptors, we demonstrated that Aβ inhibited oxidized lipoprotein binding and its subsequent degradation via CD36, but not SRA, and this was independent of Aβ-CD36-signaling. Furthermore, Aβ treatment decreased CD36, but not SRA, mRNA and protein, thereby reducing cell surface expression of this oxLDL receptor. Conclusions Together, these data demonstrate that in the presence of β-amyloid, CD36-mediated clearance of oxidized lipoproteins is abrogated, which would promote the extracellular accumulation of these pro-inflammatory lipids and perpetuate lipid peroxidation.
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Affiliation(s)
- Vidya V Kunjathoor
- Lipid Metabolism Unit, Dept. of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114 USA
| | - Anita A Tseng
- Lipid Metabolism Unit, Dept. of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114 USA
| | - Lea A Medeiros
- Lipid Metabolism Unit, Dept. of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114 USA
| | - Tayeba Khan
- Lipid Metabolism Unit, Dept. of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114 USA
| | - Kathryn J Moore
- Lipid Metabolism Unit, Dept. of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114 USA
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Husemann J, Loike JD, Anankov R, Febbraio M, Silverstein SC. Scavenger receptors in neurobiology and neuropathology: their role on microglia and other cells of the nervous system. Glia 2002; 40:195-205. [PMID: 12379907 DOI: 10.1002/glia.10148] [Citation(s) in RCA: 279] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Scavenger receptor class A (SR-A, CD204), scavenger receptor-BI (SR-BI), and CD36 are cell surface proteins that mediate cell adhesion to, and endocytosis of, various native and pathologically modified substances, and participate in intracellular signaling, lipid metabolism, and host defense against bacterial pathogens. Microglia, Mato cells, astrocytes, cerebral microvascular endothelial cells, cerebral arterial smooth muscle cells, and retinal pigment epithelial cells express one or more of these SR. Expression of SR-A and SR-BI by microglia is developmentally regulated. Neonatal microglia express SR-A and SR-BI, while microglia in normal mouse and human adult brain express neither. Astrocytes in adult brain express SR-BI. In Alzheimer's disease, microglial expression of SR-A is increased. Such findings, and evidence that SR-A and SR-BI mediate adhesion and endocytosis of fibrillar beta-amyloid by microglia and astrocytes, respectively, and that SR-A, SR-BI, and CD36 participate in secretion of reactive oxygen species by microglia, suggest roles for these receptors in homeostasis and neuropathology.
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Affiliation(s)
- Jens Husemann
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York
| | - John D Loike
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York
| | - Roman Anankov
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York
| | - Maria Febbraio
- Department of Medicine, Division of Hematology and Medical Oncology, Center of Vascular Biology, Weill Medical College of Cornell University, New York, New York
| | - Samuel C Silverstein
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York
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Coraci IS, Husemann J, Berman JW, Hulette C, Dufour JH, Campanella GK, Luster AD, Silverstein SC, El-Khoury JB. CD36, a class B scavenger receptor, is expressed on microglia in Alzheimer's disease brains and can mediate production of reactive oxygen species in response to beta-amyloid fibrils. THE AMERICAN JOURNAL OF PATHOLOGY 2002; 160:101-12. [PMID: 11786404 PMCID: PMC1867121 DOI: 10.1016/s0002-9440(10)64354-4] [Citation(s) in RCA: 302] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A pathological hallmark of Alzheimer's disease is the senile plaque, composed of beta-amyloid fibrils, microglia, astrocytes, and dystrophic neurites. We reported previously that class A scavenger receptors mediate adhesion of microglia and macrophages to beta-amyloid fibrils and oxidized low-density lipoprotein (oxLDL)-coated surfaces. We also showed that CD36, a class B scavenger receptor and an oxLDL receptor, promotes H(2)O(2) secretion by macrophages adherent to oxLDL-coated surfaces. Whether CD36 is expressed on microglia, and whether it plays a role in secretion of H(2)O(2) by microglia interacting with fibrillar beta-amyloid is not known. Using fluorescence-activated cell sorting analysis and immunohistochemistry, we found that CD36 is expressed on human fetal microglia, and N9-immortalized mouse microglia. We also found that CD36 is expressed on microglia and on vascular endothelial cells in the brains of Alzheimer's disease patients. Bowes human melanoma cells, which normally do not express CD36, gained the ability to specifically bind to surfaces coated with fibrillar beta-amyloid when transfected with a cDNA encoding human CD36, suggesting that CD36 is a receptor for fibrillar beta-amyloid. Furthermore, two different monoclonal antibodies to CD36 inhibited H(2)O(2) production by N9 microglia and human macrophages adherent to fibrillar beta-amyloid by approximately 50%. Our data identify a role for CD36 in fibrillar beta-amyloid-induced H(2)O(2) production by microglia, and imply that CD36 can mediate binding to fibrillar beta-amyloid. We propose that similar to their role in the interaction of macrophages with oxLDL, class A scavenger receptors and CD36 play complimentary roles in the interactions of microglia with fibrillar beta-amyloid.
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Affiliation(s)
- Indra Sethy Coraci
- Department of Physiology and Cellular Biophysics, Columbia University College of Physicians and Surgeons, New York, New York, USA
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