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Ma H, Zhu M, Chen M, Li X, Feng X. The role of macrophage plasticity in neurodegenerative diseases. Biomark Res 2024; 12:81. [PMID: 39135084 PMCID: PMC11321226 DOI: 10.1186/s40364-024-00624-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 07/22/2024] [Indexed: 08/15/2024] Open
Abstract
Tissue-resident macrophages and recruited macrophages play pivotal roles in innate immunity and the maintenance of brain homeostasis. Investigating the involvement of these macrophage populations in eliciting pathological changes associated with neurodegenerative diseases has been a focal point of research. Dysregulated states of macrophages can compromise clearance mechanisms for pathological proteins such as amyloid-β (Aβ) in Alzheimer's disease (AD) and TDP-43 in Amyotrophic lateral sclerosis (ALS). Additionally, recent evidence suggests that abnormalities in the peripheral clearance of pathological proteins are implicated in the pathogenesis and progression of neurodegenerative diseases. Furthermore, numerous genome-wide association studies have linked genetic risk factors, which alter the functionality of various immune cells, to the accumulation of pathological proteins. This review aims to unravel the intricacies of macrophage biology in both homeostatic conditions and neurodegenerative disorders. To this end, we initially provide an overview of the modifications in receptor and gene expression observed in diverse macrophage subsets throughout development. Subsequently, we outlined the roles of resident macrophages and recruited macrophages in neurodegenerative diseases and the progress of targeted therapy. Finally, we describe the latest advances in macrophage imaging methods and measurement of inflammation, which may provide information and related treatment strategies that hold promise for informing the design of future investigations and therapeutic interventions.
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Affiliation(s)
- Hongyue Ma
- Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China
| | - Mingxia Zhu
- Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China
| | - Mengjie Chen
- Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China
| | - Xiuli Li
- Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China
| | - Xinhong Feng
- Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China.
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2
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Castro-Gomez S, Heneka MT. Innate immune activation in neurodegenerative diseases. Immunity 2024; 57:790-814. [PMID: 38599171 DOI: 10.1016/j.immuni.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/11/2024] [Accepted: 03/11/2024] [Indexed: 04/12/2024]
Abstract
Activation of the innate immune system following pattern recognition receptor binding has emerged as one of the major pathogenic mechanisms in neurodegenerative disease. Experimental, epidemiological, pathological, and genetic evidence underscores the meaning of innate immune activation during the prodromal as well as clinical phases of several neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal dementia. Importantly, innate immune activation and the subsequent release of inflammatory mediators contribute mechanistically to other hallmarks of neurodegenerative diseases such as aberrant proteostatis, pathological protein aggregation, cytoskeleton abnormalities, altered energy homeostasis, RNA and DNA defects, and synaptic and network disbalance and ultimately to the induction of neuronal cell death. In this review, we discuss common mechanisms of innate immune activation in neurodegeneration, with particular emphasis on the pattern recognition receptors (PRRs) and other receptors involved in the detection of damage-associated molecular patterns (DAMPs).
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Affiliation(s)
- Sergio Castro-Gomez
- Center for Neurology, Department of Parkinson, Sleep and Movement Disorders, University Hospital Bonn, 53127 Bonn, Germany; Institute of Physiology II, University Hospital Bonn, 53115 Bonn, Germany
| | - Michael T Heneka
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belval, Luxembourg; Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA.
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3
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Djurišić M. Immune receptors and aging brain. Biosci Rep 2024; 44:BSR20222267. [PMID: 38299364 PMCID: PMC10866841 DOI: 10.1042/bsr20222267] [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: 07/20/2023] [Revised: 01/08/2024] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Abstract
Aging brings about a myriad of degenerative processes throughout the body. A decrease in cognitive abilities is one of the hallmark phenotypes of aging, underpinned by neuroinflammation and neurodegeneration occurring in the brain. This review focuses on the role of different immune receptors expressed in cells of the central and peripheral nervous systems. We will discuss how immune receptors in the brain act as sentinels and effectors of the age-dependent shift in ligand composition. Within this 'old-age-ligand soup,' some immune receptors contribute directly to excessive synaptic weakening from within the neuronal compartment, while others amplify the damaging inflammatory environment in the brain. Ultimately, chronic inflammation sets up a positive feedback loop that increases the impact of immune ligand-receptor interactions in the brain, leading to permanent synaptic and neuronal loss.
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Affiliation(s)
- Maja Djurišić
- Departments of Biology, Neurobiology, and Bio-X, Stanford University, Stanford, CA 94305, U.S.A
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4
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Ni J, Xie Z, Quan Z, Meng J, Qing H. How brain 'cleaners' fail: Mechanisms and therapeutic value of microglial phagocytosis in Alzheimer's disease. Glia 2024; 72:227-244. [PMID: 37650384 DOI: 10.1002/glia.24465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/10/2023] [Accepted: 08/19/2023] [Indexed: 09/01/2023]
Abstract
Microglia are the resident phagocytes of the brain, where they primarily function in the clearance of dead cells and the removal of un- or misfolded proteins. The impaired activity of receptors or proteins involved in phagocytosis can result in enhanced inflammation and neurodegeneration. RNA-seq and genome-wide association studies have linked multiple phagocytosis-related genes to neurodegenerative diseases, while the knockout of such genes has been demonstrated to exert protective effects against neurodegeneration in animal models. The failure of microglial phagocytosis influences AD-linked pathologies, including amyloid β accumulation, tau propagation, neuroinflammation, and infection. However, a precise understanding of microglia-mediated phagocytosis in Alzheimer's disease (AD) is still lacking. In this review, we summarize current knowledge of the molecular mechanisms involved in microglial phagocytosis in AD across a wide range of pre-clinical, post-mortem, ex vivo, and clinical studies and review the current limitations regarding the detection of microglia phagocytosis in AD. Finally, we discuss the rationale of targeting microglial phagocytosis as a therapeutic strategy for preventing AD or slowing its progression.
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Affiliation(s)
- Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhen Xie
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhenzhen Quan
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jie Meng
- Department of Geriatrics, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China
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5
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Rathod SS, Agrawal YO. Phytocannabinoids as Potential Multitargeting Neuroprotectants in Alzheimer's Disease. Curr Drug Res Rev 2024; 16:94-110. [PMID: 37132109 DOI: 10.2174/2589977515666230502104021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 05/04/2023]
Abstract
The Endocannabinoid System (ECS) is a well-studied system that influences a variety of physiological activities. It is evident that the ECS plays a significant role in metabolic activities and also has some neuroprotective properties. In this review, we emphasize several plant-derived cannabinoids such as β-caryophyllene (BCP), Cannabichromene (CBC), Cannabigerol (CBG), Cannabidiol (CBD), and Cannabinol (CBN), which are known to have distinctive modulation abilities of ECS. In Alzheimer's disease (AD), the activation of ECS may provide neuroprotection by modulating certain neuronal circuitry pathways through complex molecular cascades. The present article also discusses the implications of cannabinoid receptors (CB1 and CB2) as well as cannabinoid enzymes (FAAH and MAGL) modulators in AD. Specifically, CBR1 or CB2R modulations result in reduced inflammatory cytokines such as IL-2 and IL-6, as well as a reduction in microglial activation, which contribute to an inflammatory response in neurons. Furthermore, naturally occurring cannabinoid metabolic enzymes (FAAH and MAGL) inhibit the NLRP3 inflammasome complex, which may offer significant neuroprotection. In this review, we explored the multi-targeted neuroprotective properties of phytocannabinoids and their possible modulations, which could offer significant benefits in limiting AD.
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Affiliation(s)
- Sumit S Rathod
- Department of Pharmacy, R.C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dist. Dhule, 425405, Maharashtra, India
- Shri Vile Parle Kelavani Mandal's, Institute of Pharmacy, Dhule, Dist. Dhule, 424001, Maharashtra, India
| | - Yogeeta O Agrawal
- Department of Pharmacy, R.C. Patel Institute of Pharmaceutical Education and Research, Shirpur, Dist. Dhule, 425405, Maharashtra, India
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Zhu Z, Zhang L, Elsherbini A, Crivelli SM, Tripathi P, Harper C, Quadri Z, Spassieva SD, Bieberich E. The S1P receptor 1 antagonist Ponesimod reduces TLR4-induced neuroinflammation and increases Aβ clearance in 5XFAD mice. EBioMedicine 2023; 94:104713. [PMID: 37480622 PMCID: PMC10393615 DOI: 10.1016/j.ebiom.2023.104713] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/24/2023] Open
Abstract
BACKGROUND Previously, we showed that the sphingosine-1-phosphate (S1P) transporter spinster 2 (Spns2) mediates activation of microglia in response to amyloid β peptide (Aβ). Here, we investigated if Ponesimod, a functional S1P receptor 1 (S1PR1) antagonist, prevents Aβ-induced activation of glial cells and Alzheimer's disease (AD) pathology. METHODS We used primary cultures of glial cells and the 5XFAD mouse model to determine the effect of Aβ and Ponesimod on glial activation, Aβ phagocytosis, cytokine levels and pro-inflammatory signaling pathways, AD pathology, and cognitive performance. FINDINGS Aβ42 increased the levels of TLR4 and S1PR1, leading to their complex formation. Ponesimod prevented the increase in TLR4 and S1PR1 levels, as well as the formation of their complex. It also reduced the activation of the pro-inflammatory Stat1 and p38 MAPK signaling pathways, while activating the anti-inflammatory Stat6 pathway. This was consistent with increased phagocytosis of Aβ42 in primary cultured microglia. In 5XFAD mice, Ponesimod decreased the levels of TNF-α and CXCL10, which activate TLR4 and Stat1. It also increased the level of IL-33, an anti-inflammatory cytokine that promotes Aβ42 phagocytosis by microglia. As a result of these changes, Ponesimod decreased the number of Iba-1+ microglia and GFAP+ astrocytes, and the size and number of amyloid plaques, while improving spatial memory as measured in a Y-maze test. INTERPRETATION Ponesimod targeting S1PR1 is a promising therapeutic approach to reprogram microglia, reduce neuroinflammation, and increase Aβ clearance in AD. FUNDING NIHR01AG064234, RF1AG078338, R21AG078601, VAI01BX003643.
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Affiliation(s)
- Zhihui Zhu
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Liping Zhang
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Ahmed Elsherbini
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Simone M Crivelli
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Priyanka Tripathi
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Carmen Harper
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Zainuddin Quadri
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Stefka D Spassieva
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, United States; Veterans Affairs Medical Center, Lexington, KY 40502, United States.
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Parajuli B, Koizumi S. Strategies for Manipulating Microglia to Determine Their Role in the Healthy and Diseased Brain. Neurochem Res 2023; 48:1066-1076. [PMID: 36085395 PMCID: PMC9462627 DOI: 10.1007/s11064-022-03742-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/08/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022]
Abstract
Microglia are the specialized macrophages of the central nervous system and play an important role in neural circuit development, modulating neurotransmission, and maintaining brain homeostasis. Microglia in normal brain is quiescent and show ramified morphology with numerous branching processes. They constantly survey their surrounding microenvironment through the extension and retraction of their processes and interact with neurons, astrocytes, and blood vessels using these processes. Microglia respond quickly to any pathological event in the brain by assuming ameboid morphology devoid of branching processes and restore homeostasis. However, when there is chronic inflammation, microglia may lose their homeostatic functions and secrete various proinflammatory cytokines and mediators that initiate neural dysfunction and neurodegeneration. In this article, we review the role of microglia in the normal brain and in various pathological brain conditions, such as Alzheimer's disease and multiple sclerosis. We describe strategies to manipulate microglia, focusing on depletion, repopulation, and replacement, and we discuss their therapeutic potential.
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Affiliation(s)
- Bijay Parajuli
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
- GLIA Center, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
- GLIA Center, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
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8
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Dabi YT, Ajagbe AO, Degechisa ST. Toll-like receptors in pathogenesis of neurodegenerative diseases and their therapeutic potential. Immun Inflamm Dis 2023; 11:e839. [PMID: 37102648 PMCID: PMC10116887 DOI: 10.1002/iid3.839] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/17/2023] [Accepted: 03/29/2023] [Indexed: 04/28/2023] Open
Abstract
Toll-like receptors (TLRs) are a family of pattern-recognition receptors triggered by pathogen-derived and tissue-damage-related ligands. TLRs were previously believed to only be expressed in immune cells. However, it is now confirmed that they are ubiquitously expressed in cells within the body including neurons, astrocytes, and microglia of the central nervous system (CNS). Activation of TLRs is capable of inducing immunologic and inflammatory responses to injury or infection of CNS. This response is self-limiting that usually resolves once the infection has been eradicated or the tissue damage has been repaired. However, the persistence of inflammation-inducing insults or a failure in normal resolution mechanisms may result in overwhelming inflammation which may induce neurodegeneration. This implies that TLRs may play a role in mediating the link between inflammation and neurodegenerative diseases namely Alzheimer's disease, Parkinson's disease, Huntington's disease, stroke, and amyotrophic lateral sclerosis. So, new therapeutic approaches that specifically target TLRs may be developed by better understanding TLR expression mechanisms in the CNS and their connections to particular neurodegenerative disorders. Therefore, this review paper discussed the role of TLRs in neurodegenerative diseases.
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Affiliation(s)
- Yosef Tsegaye Dabi
- Department of Medical Laboratory Science, Institute of Health SciencesWollega UniversityNekemteEthiopia
| | - Abayomi O. Ajagbe
- Department of Anatomy, College of Health Sciences, Faculty of Basic Medical SciencesNile University of NigeriaAbujaNigeria
| | - Sisay T. Degechisa
- Department of Medical Biochemistry, School of Medicine, College of Health SciencesAddis Ababa UniversityAddis AbabaEthiopia
- Department of Medical Laboratory Sciences, College of Medicine and Health SciencesArba Minch UniversityArba MinchEthiopia
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9
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Zhao J, Wang X, He Y, Xu P, Lai L, Chung Y, Pan X. The Role of T Cells in Alzheimer's Disease Pathogenesis. Crit Rev Immunol 2023; 43:15-23. [PMID: 37943150 DOI: 10.1615/critrevimmunol.2023050145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder associated with memory decline and cognitive impairment, which is related to hallmark protein aggregates, amyloid-β (Аβ) plaques and neurofibrillary tangles; the latter are accumulated with hyperphosphorylated Tau protein. Immune cells play an important role in AD pathogenesis. Although the role of T cells in AD remains controversial, studies have shown that T cell deficiency is associated with increased AD pathology. In contrast, transplantation of T cells reduces AD pathology. T cells can help B cells generate anti-Аβ antibody to neutralize the toxin of Аβ and hyperphosphorylated Tau. T cells also activate macrophages to phagocytose misfolded proteins including Аβ and Tau. Recent data have also shown that AD animals have a damaged thymic microenvironment, especially thymic epithelial cells (TECs), resulting in decreased T cell numbers, which contribute to AD pathology. Therefore, regulation of T cell regeneration, for example by rejuvenating the thymic microenvironment, has the potential to be used in the treatment of AD.
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Affiliation(s)
- Jin Zhao
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, Guangdong, 510515, China; ZhuHai Hengqin ImStem Biotechnology Co. Ltd., Hengqin New District Huandao Donglu 1889 Building 3, Zhuhai, Guangdong, 519000, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong Province Key Laboratory of Psychiatric Disorders, School of Basic Medical Sciences, Southern Medical University, Guangdong, 510515, China
| | - Xiaofang Wang
- ZhuHai Hengqin ImStem Biotechnology Co. Ltd., Hengqin New District Huandao Donglu 1889 Building 3, Zhuhai, Guangdong, 519000, China; ImStem Biotechnology, Inc., 400 Farmington Avenue R1808, Farmington, CT 06030, USA
| | - Yusheng He
- ZhuHai Hengqin ImStem Biotechnology Co. Ltd., Hengqin New District Huandao Donglu 1889 Building 3, Zhuhai, Guangdong, 519000, China
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Laijun Lai
- Department of Allied Health Sciences, University of Connecticut, Storrs, CT, USA; University of Connecticut Stem Cell Institute, University of Connecticut, Storrs, CT, USA
| | - Younggie Chung
- ZhuHai Hengqin ImStem Biotechnology Co. Ltd., Hengqin New District Huandao Donglu 1889 Building 3, Zhuhai, Guangdong, 519000, China; ImStem Biotechnology, Inc., 400 Farmington Avenue R1808, Farmington, CT 06030, USA
| | - Xinghua Pan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, and Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Guangzhou, Guangdong, 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong Province Key Laboratory of Psychiatric Disorders, School of Basic Medical Sciences, Southern Medical University, Guangdong, 510515, China
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10
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Huang Z. A Function of Amyloid-β in Mediating Activity-Dependent Axon/Synapse Competition May Unify Its Roles in Brain Physiology and Pathology. J Alzheimers Dis 2023; 92:29-57. [PMID: 36710681 PMCID: PMC10023438 DOI: 10.3233/jad-221042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Amyloid-β protein precursor (AβPP) gives rise to amyloid-β (Aβ), a peptide at the center of Alzheimer's disease (AD). AβPP, however, is also an ancient molecule dating back in evolution to some of the earliest forms of metazoans. This suggests a possible ancestral function that may have been obscured by those that evolve later. Based on literature from the functions of Aβ/AβPP in nervous system development, plasticity, and disease, to those of anti-microbial peptides (AMPs) in bacterial competition as well as mechanisms of cell competition uncovered first by Drosophila genetics, I propose that Aβ/AβPP may be part of an ancient mechanism employed in cell competition, which is subsequently co-opted during evolution for the regulation of activity-dependent neural circuit development and plasticity. This hypothesis is supported by foremost the high similarities of Aβ to AMPs, both of which possess unique, opposite (i.e., trophic versus toxic) activities as monomers and oligomers. A large body of data further suggests that the different Aβ oligomeric isoforms may serve as the protective and punishment signals long predicted to mediate activity-dependent axonal/synaptic competition in the developing nervous system and that the imbalance in their opposite regulation of innate immune and glial cells in the brain may ultimately underpin AD pathogenesis. This hypothesis can not only explain the diverse roles observed of Aβ and AβPP family molecules, but also provide a conceptual framework that can unify current hypotheses on AD. Furthermore, it may explain major clinical observations not accounted for and identify approaches for overcoming shortfalls in AD animal modeling.
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Affiliation(s)
- Zhen Huang
- Departments of Neuroscience and Neurology, University of Wisconsin-Madison, Madison, WI, USA
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11
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Das TK, Ganesh BP. Interlink between the gut microbiota and inflammation in the context of oxidative stress in Alzheimer's disease progression. Gut Microbes 2023; 15:2206504. [PMID: 37127846 PMCID: PMC10153019 DOI: 10.1080/19490976.2023.2206504] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
The microbiota-gut-brain axis is an important pathway of communication and may dynamically contribute to Alzheimer's disease (AD) pathogenesis. Pathological commensal gut microbiota alterations, termed as dysbiosis, can influence intestinal permeability and break the blood-brain barrier which may trigger AD pathogenesis via redox signaling, neuronal, immune, and metabolic pathways. Dysbiosis increases the oxidative stress. Oxidants affect the innate immune system through recognizing microbial-derived pathogens by Toll-like receptors and initiating the inflammatory process. Most of the gut microbiome research work highlights the relationship between the gut microbiota and AD, but the contributory connection between precise bacteria and brain dysfunction in AD pathology cannot be fully demonstrated. Here, we summarize the current information of the fundamental connections between oxidative stress, inflammation, and gut dysbiosis in AD. This review emphasizes on the involvement of gut microbiota in the regulation of oxidative stress, inflammation, immune responses including central and peripheral cross-talk. It provides insights for novel preventative and therapeutic approaches in AD.
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Affiliation(s)
- Tushar K Das
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Bhanu P Ganesh
- Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
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12
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Hou J, Chen Y, Grajales-Reyes G, Colonna M. TREM2 dependent and independent functions of microglia in Alzheimer's disease. Mol Neurodegener 2022; 17:84. [PMID: 36564824 PMCID: PMC9783481 DOI: 10.1186/s13024-022-00588-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 12/02/2022] [Indexed: 12/25/2022] Open
Abstract
Microglia are central players in brain innate immunity and have been the subject of extensive research in Alzheimer's disease (AD). In this review, we aim to summarize the genetic and functional discoveries that have advanced our understanding of microglia reactivity to AD pathology. Given the heightened AD risk posed by rare variants of the microglial triggering receptor expressed on myeloid cells 2 (TREM2), we will focus on the studies addressing the impact of this receptor on microglia responses to amyloid plaques, tauopathy and demyelination pathologies in mouse and human. Finally, we will discuss the implications of recent discoveries on microglia and TREM2 biology on potential therapeutic strategies for AD.
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Affiliation(s)
- Jinchao Hou
- grid.4367.60000 0001 2355 7002Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Yun Chen
- grid.4367.60000 0001 2355 7002Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110 USA ,grid.4367.60000 0001 2355 7002Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Gary Grajales-Reyes
- grid.4367.60000 0001 2355 7002Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110 USA
| | - Marco Colonna
- grid.4367.60000 0001 2355 7002Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110 USA
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13
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Saavedra J, Nascimento M, Liz MA, Cardoso I. Key brain cell interactions and contributions to the pathogenesis of Alzheimer's disease. Front Cell Dev Biol 2022; 10:1036123. [PMID: 36523504 PMCID: PMC9745159 DOI: 10.3389/fcell.2022.1036123] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 11/14/2022] [Indexed: 06/22/2024] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide, with the two major hallmarks being the deposition of extracellular β-amyloid (Aβ) plaques and of intracellular neurofibrillary tangles (NFTs). Additionally, early pathological events such as cerebrovascular alterations, a compromised blood-brain barrier (BBB) integrity, neuroinflammation and synaptic dysfunction, culminate in neuron loss and cognitive deficits. AD symptoms reflect a loss of neuronal circuit integrity in the brain; however, neurons do not operate in isolation. An exclusively neurocentric approach is insufficient to understand this disease, and the contribution of other brain cells including astrocytes, microglia, and vascular cells must be integrated in the context. The delicate balance of interactions between these cells, required for healthy brain function, is disrupted during disease. To design successful therapies, it is critical to understand the complex brain cellular connections in AD and the temporal sequence of their disturbance. In this review, we discuss the interactions between different brain cells, from physiological conditions to their pathological reactions in AD, and how this basic knowledge can be crucial for developing new therapeutic strategies.
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Affiliation(s)
- Joana Saavedra
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Mariana Nascimento
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Márcia A. Liz
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Isabel Cardoso
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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14
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Busch L, Eggert S, Endres K, Bufe B. The Hidden Role of Non-Canonical Amyloid β Isoforms in Alzheimer's Disease. Cells 2022; 11:3421. [PMID: 36359817 PMCID: PMC9654995 DOI: 10.3390/cells11213421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 09/08/2024] Open
Abstract
Recent advances have placed the pro-inflammatory activity of amyloid β (Aβ) on microglia cells as the focus of research on Alzheimer's Disease (AD). Researchers are confronted with an astonishing spectrum of over 100 different Aβ variants with variable length and chemical modifications. With the exception of Aβ1-42 and Aβ1-40, the biological significance of most peptides for AD is as yet insufficiently understood. We therefore aim to provide a comprehensive overview of the contributions of these neglected Aβ variants to microglia activation. First, the impact of Aβ receptors, signaling cascades, scavenger mechanisms, and genetic variations on the physiological responses towards various Aβ species is described. Furthermore, we discuss the importance of different types of amyloid precursor protein processing for the generation of these Aβ variants in microglia, astrocytes, oligodendrocytes, and neurons, and highlight how alterations in secondary structures and oligomerization affect Aβ neurotoxicity. In sum, the data indicate that gene polymorphisms in Aβ-driven signaling pathways in combination with the production and activity of different Aβ variants might be crucial factors for the initiation and progression of different forms of AD. A deeper assessment of their interplay with glial cells may pave the way towards novel therapeutic strategies for individualized medicine.
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Affiliation(s)
- Lukas Busch
- Department of Informatics and Microsystems Technology, University of Applied Sciences Kaiserslautern, D-66482 Zweibruecken, Germany
| | - Simone Eggert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, D-37075 Goettingen, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Centre of the Johannes Gutenberg University, D-55131 Mainz, Germany
| | - Bernd Bufe
- Department of Informatics and Microsystems Technology, University of Applied Sciences Kaiserslautern, D-66482 Zweibruecken, Germany
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15
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Sušjan-Leite P, Ramuta TŽ, Boršić E, Orehek S, Hafner-Bratkovič I. Supramolecular organizing centers at the interface of inflammation and neurodegeneration. Front Immunol 2022; 13:940969. [PMID: 35979366 PMCID: PMC9377691 DOI: 10.3389/fimmu.2022.940969] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/05/2022] [Indexed: 11/17/2022] Open
Abstract
The pathogenesis of neurodegenerative diseases involves the accumulation of misfolded protein aggregates. These deposits are both directly toxic to neurons, invoking loss of cell connectivity and cell death, and recognized by innate sensors that upon activation release neurotoxic cytokines, chemokines, and various reactive species. This neuroinflammation is propagated through signaling cascades where activated sensors/receptors, adaptors, and effectors associate into multiprotein complexes known as supramolecular organizing centers (SMOCs). This review provides a comprehensive overview of the SMOCs, involved in neuroinflammation and neurotoxicity, such as myddosomes, inflammasomes, and necrosomes, their assembly, and evidence for their involvement in common neurodegenerative diseases. We discuss the multifaceted role of neuroinflammation in the progression of neurodegeneration. Recent progress in the understanding of particular SMOC participation in common neurodegenerative diseases such as Alzheimer's disease offers novel therapeutic strategies for currently absent disease-modifying treatments.
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Affiliation(s)
- Petra Sušjan-Leite
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Taja Železnik Ramuta
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Elvira Boršić
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Sara Orehek
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Iva Hafner-Bratkovič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Ljubljana, Slovenia
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16
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Lin C, Xu C, Zhou Y, Chen A, Jin B. Identification of Biomarkers Related to M2 Macrophage Infiltration in Alzheimer’s Disease. Cells 2022; 11:cells11152365. [PMID: 35954209 PMCID: PMC9367736 DOI: 10.3390/cells11152365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 02/01/2023] Open
Abstract
Many studies have demonstrated that neuroinflammation contributes to the onset and development of Alzheimer’s disease (AD). The infiltration of immune cells in the brain was observed in AD. The purpose of the present study was to verify potential mechanisms and screen out biomarkers related to immune infiltration in AD. We collected the expression profiling datasets of AD patients and healthy donors from the NCBI’s Gene Expression Omnibus (GEO) database. We confirmed that immune-related mechanisms were involved in AD using differentially expressed genes analysis and functional enrichment analysis. We then found that M2 macrophage infiltration was most positively correlated with AD according to the CIBERSORT algorithm and a weighted gene co-expression network analysis (WGCNA). TLR2, FCGR2A, ITGB2, NCKAP1L and CYBA were identified as hub genes correlated with M2 macrophage infiltration in AD. Furthermore, the expression levels of these hub genes were positively correlated with Aβ42 and β-secretase activity. A diagnostic model of these hub genes was constructed, which showed a high area under the curve (AUC) value in both the derivation and validation cohorts. Overall, our work further expanded our understanding of the immunological mechanisms of AD and provided new insights into therapeutic strategies in AD.
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Affiliation(s)
- Caixiu Lin
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
- Department of Neurology, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Congcong Xu
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
| | - Yongji Zhou
- Department of Neurology, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China;
| | - Anqi Chen
- The Research Institute of Advanced Technologies, Ningbo University, Ningbo 315211, China;
| | - Baiye Jin
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China; (C.L.); (C.X.)
- Correspondence:
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17
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Wang Y, Lv S, Zhou X, Niu X, Chen L, Yang Z, Peng D. Identification of TLR2 as a Key Target in Neuroinflammation in Vascular Dementia. Front Genet 2022; 13:860122. [PMID: 35873459 PMCID: PMC9296774 DOI: 10.3389/fgene.2022.860122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Vascular dementia (VaD) is the second most common cause of dementia. At present, precise molecular processes of VaD are unclear. We attempted to discover the VaD relevant candidate genes, enrichment biological processes and pathways, key targets, and the underlying mechanism by microarray bioinformatic analysis. We selected GSE122063 related to the autopsy samples of VaD for analysis. We first took use of Weighted Gene Co-expression Network Analysis (WGCNA) to achieve modules related to VaD and hub genes. Second, we filtered out significant differentially expressed genes (DEGs). Third, significant DEGs then went through Geno Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Fourth, Gene Set Enrichment Analysis (GSEA) was performed. At last, we constructed the protein–protein interaction (PPI) network. The results showed that the yellow module had the strongest correlation with VaD, and we finally identified 21 hub genes. Toll-like receptor 2 (TLR2) was the top hub gene and was strongly correlated with other possible candidate genes. In total, 456 significant DEGs were filtered out and these genes were found to be enriched in the Toll receptor signaling pathway and several other immune-related pathways. In addition, Gene Set Enrichment Analysis results showed that similar pathways were significantly over-represented in TLR2-high samples. In the PPI network, TLR2 was still an important node with high weight and combined scores. We concluded that the TLR2 acts as a key target in neuroinflammation which may participate in the pathophysiological process of VaD.
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Affiliation(s)
- Yuye Wang
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Shuang Lv
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Xiao Zhou
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoqian Niu
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Leian Chen
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ziyuan Yang
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
| | - Dantao Peng
- Department of Neurology, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Peking University China-Japan Friendship School of Clinical Medicine, Beijing, China
- *Correspondence: Dantao Peng,
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18
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Microglia in Alzheimer’s Disease: A Favorable Cellular Target to Ameliorate Alzheimer’s Pathogenesis. Mediators Inflamm 2022; 2022:6052932. [PMID: 35693110 PMCID: PMC9184163 DOI: 10.1155/2022/6052932] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 05/09/2022] [Indexed: 11/18/2022] Open
Abstract
Microglial cells serve as molecular sensors of the brain that play a role in physiological and pathological conditions. Under normal physiology, microglia are primarily responsible for regulating central nervous system homeostasis through the phagocytic clearance of redundant protein aggregates, apoptotic cells, damaged neurons, and synapses. Furthermore, microglial cells can promote and mitigate amyloid β phagocytosis and tau phosphorylation. Dysregulation of the microglial programming alters cellular morphology, molecular signaling, and secretory inflammatory molecules that contribute to various neurodegenerative disorders especially Alzheimer’s disease (AD). Furthermore, microglia are considered primary sources of inflammatory molecules and can induce or regulate a broad spectrum of cellular responses. Interestingly, in AD, microglia play a double-edged role in disease progression; for instance, the detrimental microglial effects increase in AD while microglial beneficiary mechanisms are jeopardized. Depending on the disease stages, microglial cells are expressed differently, which may open new avenues for AD therapy. However, the disease-related role of microglial cells and their receptors in the AD brain remain unclear. Therefore, this review represents the role of microglial cells and their involvement in AD pathogenesis.
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19
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Revuelta M, Urrutia J, Villarroel A, Casis O. Microglia-Mediated Inflammation and Neural Stem Cell Differentiation in Alzheimer's Disease: Possible Therapeutic Role of K V1.3 Channel Blockade. Front Cell Neurosci 2022; 16:868842. [PMID: 35530176 PMCID: PMC9070300 DOI: 10.3389/fncel.2022.868842] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/31/2022] [Indexed: 12/14/2022] Open
Abstract
Increase of deposits of amyloid β peptides in the extracellular matrix is landmark during Alzheimer’s Disease (AD) due to the imbalance in the production vs. clearance. This accumulation of amyloid β deposits triggers microglial activation. Microglia plays a dual role in AD, a protective role by clearing the deposits of amyloid β peptides increasing the phagocytic response (CD163, IGF-1 or BDNF) and a cytotoxic role, releasing free radicals (ROS or NO) and proinflammatory cytokines (TNF-α, IL-1β) in response to reactive gliosis activated by the amyloid β aggregates. Microglia activation correlated with an increase KV1.3 channels expression, protein levels and current density. Several studies highlight the importance of KV1.3 in the activation of inflammatory response and inhibition of neural progenitor cell proliferation and neuronal differentiation. However, little is known about the pathways of this activation in neural stem cells differentiation and proliferation and the role in amyloid β accumulation. In recent studies using in vitro cells derived from mice models, it has been demonstrated that KV1.3 blockers inhibit microglia-mediated neurotoxicity in culture reducing the expression and production of the pro-inflammatory cytokines IL-1β and TNF-α through the NF-kB and p38MAPK pathway. Overall, we conclude that KV1.3 blockers change the course of AD development, reducing microglial cytotoxic activation and increasing neural stem cell differentiation. However, further investigations are needed to establish the specific pathway and to validate the use of this blocker as therapeutic treatment in Alzheimer patients.
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Affiliation(s)
- Miren Revuelta
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Janire Urrutia
- Department of Physiology, Faculty of Medicine and Nursery, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Alvaro Villarroel
- Instituto Biofisika, Consejo Superior de Investigaciones Científicas (CSIC)-University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), Leioa, Spain
| | - Oscar Casis
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain
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20
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McManus RM. The Role of Immunity in Alzheimer's Disease. Adv Biol (Weinh) 2022; 6:e2101166. [PMID: 35254006 DOI: 10.1002/adbi.202101166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 02/03/2022] [Indexed: 01/27/2023]
Abstract
With the increase in the aging population, age-related conditions such as dementia and Alzheimer's disease will become ever more prevalent in society. As there is no cure for dementia and extremely limited therapeutic options, researchers are examining the mechanisms that contribute to the progression of cognitive decline in hopes of developing better therapies and even an effective, long-lasting treatment for this devastating condition. This review will provide an updated perspective on the role of immunity in triggering the changes that lead to the development of dementia. It will detail the latest findings on Aβ- and tau-induced microglial activation, including the role of the inflammasome. The contribution of the adaptive immune system, specifically T cells, will be discussed. Finally, whether the innate and adaptive immune system can be modulated to protect against dementia will be examined, along with an assessment of the prospective candidates for these that are currently in clinical trials.
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Affiliation(s)
- Róisín M McManus
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, Germany
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21
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Szabo MP, Iba M, Nath A, Masliah E, Kim C. Does SARS-CoV-2 affect neurodegenerative disorders? TLR2, a potential receptor for SARS-CoV-2 in the CNS. Exp Mol Med 2022; 54:447-454. [PMID: 35396576 PMCID: PMC8990637 DOI: 10.1038/s12276-022-00755-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/13/2022] [Indexed: 12/15/2022] Open
Abstract
The coronavirus (COVID-19) pandemic, caused by severe acute respiratory system coronavirus 2 (SARS-CoV-2), has created significant challenges for scientists seeking to understand the pathogenic mechanisms of SARS-CoV-2 infection and to identify the best therapies for infected patients. Although ACE2 is a known receptor for the virus and has been shown to mediate viral entry into the lungs, accumulating reports highlight the presence of neurological symptoms resulting from infection. As ACE2 expression is low in the central nervous system (CNS), these neurological symptoms are unlikely to be caused by ACE2-virus binding. In this review, we will discuss a proposed interaction between SARS-CoV-2 and Toll-like receptor 2 (TLR2) in the CNS. TLR2 is an innate immune receptor that recognizes exogenous microbial components but has also been shown to interact with multiple viral components, including the envelope (E) protein of SARS-CoV-2. In addition, TLR2 plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Based on these observations, we hypothesize that TLR2 may play a critical role in the response to SARS-CoV-2 infiltration in the CNS, thereby resulting in the induction or acceleration of AD and PD pathologies in patients.
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Affiliation(s)
- Marcell P Szabo
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michiyo Iba
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eliezer Masliah
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA. .,Division of Neuroscience, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Changyoun Kim
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
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22
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Fairless R, Bading H, Diem R. Pathophysiological Ionotropic Glutamate Signalling in Neuroinflammatory Disease as a Therapeutic Target. Front Neurosci 2021; 15:741280. [PMID: 34744612 PMCID: PMC8567076 DOI: 10.3389/fnins.2021.741280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/30/2021] [Indexed: 01/15/2023] Open
Abstract
Glutamate signalling is an essential aspect of neuronal communication involving many different glutamate receptors, and underlies the processes of memory, learning and synaptic plasticity. Despite neuroinflammatory diseases covering a range of maladies with very different biological causes and pathophysiologies, a central role for dysfunctional glutamate signalling is becoming apparent. This is not just restricted to the well-described role of glutamate in mediating neurodegeneration, but also includes a myriad of other influences that glutamate can exert on the vasculature, as well as immune cell and glial regulation, reflecting the ability of neurons to communicate with these compartments in order to couple their activity with neuronal requirements. Here, we discuss the role of pathophysiological glutamate signalling in neuroinflammatory disease, using both multiple sclerosis and Alzheimer's disease as examples, and how current steps are being made to harness our growing understanding of these processes in the development of neuroprotective strategies. This review focuses in particular on N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methylisooxazol-4-yl) propionate (AMPA) type ionotropic glutamate receptors, although metabotropic, G-protein-coupled glutamate receptors may also contribute to neuroinflammatory processes. Given the indispensable roles of glutamate-gated ion channels in synaptic communication, means of pharmacologically distinguishing between physiological and pathophysiological actions of glutamate will be discussed that allow deleterious signalling to be inhibited whilst minimising the disturbance of essential neuronal function.
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Affiliation(s)
- Richard Fairless
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hilmar Bading
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Ricarda Diem
- Department of Neurology, University Clinic Heidelberg, Heidelberg, Germany.,Clinical Cooperation Unit (CCU) Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
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23
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Adhikarla SV, Jha NK, Goswami VK, Sharma A, Bhardwaj A, Dey A, Villa C, Kumar Y, Jha SK. TLR-Mediated Signal Transduction and Neurodegenerative Disorders. Brain Sci 2021; 11:brainsci11111373. [PMID: 34827372 PMCID: PMC8615980 DOI: 10.3390/brainsci11111373] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/16/2021] [Accepted: 10/16/2021] [Indexed: 11/16/2022] Open
Abstract
A special class of proteins called Toll-like receptors (TLRs) are an essential part of the innate immune system, connecting it to the adaptive immune system. There are 10 different Toll-Like Receptors that have been identified in human beings. TLRs are part of the central nervous system (CNS), showing that the CNS is capable of the immune response, breaking the long-held belief of the brain's "immune privilege" owing to the blood-brain barrier (BBB). These Toll-Like Receptors are present not just on the resident macrophages of the central nervous system but are also expressed by the neurons to allow them for the production of proinflammatory agents such as interferons, cytokines, and chemokines; the activation and recruitment of glial cells; and their participation in neuronal cell death by apoptosis. This study is focused on the potential roles of various TLRs in various neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD), namely TLR2, TLR3, TLR4, TLR7, and TLR9 in AD and PD in human beings and a mouse model.
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Affiliation(s)
- Shashank Vishwanath Adhikarla
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology (Formerly NSIT, University of Delhi), New Delhi 110078, India;
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
| | - Vineet Kumar Goswami
- Department of Biotechnology, Delhi Technological University, Delhi 110042, India;
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
| | - Ankur Sharma
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
- Department of Life Science, School of Basic Science & Research (SBSR), Sharda University, Greater Noida 201310, India
| | - Anuradha Bhardwaj
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
| | - Abhijit Dey
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata 700073, India;
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy;
| | - Yatender Kumar
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology (Formerly NSIT, University of Delhi), New Delhi 110078, India;
- Correspondence: (Y.K.); (S.K.J.)
| | - Saurabh Kumar Jha
- Department of Biotechnology, School of Engineering & Technology (SET), Sharda University, Greater Noida 201310, India; (N.K.J.); (A.B.)
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham 2770, Australia;
- Correspondence: (Y.K.); (S.K.J.)
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24
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Chen SH, He CY, Shen YY, Zeng GH, Tian DY, Cheng Y, Xu MY, Fan DY, Tan CR, Shi AY, Bu XL, Wang YJ. Polysaccharide Krestin Prevents Alzheimer's Disease-type Pathology and Cognitive Deficits by Enhancing Monocyte Amyloid-β Processing. Neurosci Bull 2021; 38:290-302. [PMID: 34611829 PMCID: PMC8975919 DOI: 10.1007/s12264-021-00779-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/18/2021] [Indexed: 10/20/2022] Open
Abstract
Deficits in the clearance of amyloid β protein (Aβ) by the peripheral system play a critical role in the pathogenesis of sporadic Alzheimer's disease (AD). Impaired uptake of Aβ by dysfunctional monocytes is deemed to be one of the major mechanisms underlying deficient peripheral Aβ clearance in AD. In the current study, flow cytometry and biochemical and behavioral techniques were applied to investigate the effects of polysaccharide krestin (PSK) on AD-related pathology in vitro and in vivo. We found that PSK, widely used in therapy for various cancers, has the potential to enhance Aβ uptake and intracellular processing by human monocytes in vitro. After administration of PSK by intraperitoneal injection, APP/PS1 mice performed better in behavioral tests, along with reduced Aβ deposition, neuroinflammation, neuronal loss, and tau hyperphosphorylation. These results suggest that PSK holds promise as a preventive agent for AD by strengthening the Aβ clearance by blood monocytes and alleviating AD-like pathology.
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Affiliation(s)
- Si-Han Chen
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China ,grid.449525.b0000 0004 1798 4472Department of Neurology, Nanchong Central Hospital, The Second Clinical Medical School, North Sichuan Medical College, Nanchong, 637000 China
| | - Chen-Yang He
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Ying-Ying Shen
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Gui-Hua Zeng
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Ding-Yuan Tian
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Yuan Cheng
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Man-Yu Xu
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Dong-Yu Fan
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Cheng-Rong Tan
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - An-Yu Shi
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042 China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042 China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042 China
| | - Xian-Le Bu
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China. .,The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042, China. .,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042, China. .,State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
| | - Yan-Jiang Wang
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China. .,The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042, China. .,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042, China. .,State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing, 400042, China. .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 201200, China.
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25
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Uddin MS, Kabir MT, Jalouli M, Rahman MA, Jeandet P, Behl T, Alexiou A, Albadrani GM, Abdel-Daim MM, Perveen A, Ashraf GM. Neuroinflammatory Signaling in the Pathogenesis of Alzheimer's Disease. Curr Neuropharmacol 2021; 20:126-146. [PMID: 34525932 PMCID: PMC9199559 DOI: 10.2174/1570159x19666210826130210] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 04/16/2021] [Accepted: 05/10/2021] [Indexed: 11/22/2022] Open
Abstract
Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the formation of intracellular neurofibrillary tangles (NFTs) and extracellular amyloid plaques. Growing evidence has suggested that AD pathogenesis is not only limited to the neuronal compartment but also strongly interacts with immunological processes in the brain. On the other hand, aggregated and misfolded proteins can bind with pattern recognition receptors located on astroglia and microglia and can, in turn, induce an innate immune response, characterized by the release of inflammatory mediators, ultimately playing a role in both the severity and the progression of the disease. It has been reported by genome-wide analysis that several genes which elevate the risk for sporadic AD encode for factors controlling the inflammatory response and glial clearance of misfolded proteins. Obesity and systemic inflammation are examples of external factors which may interfere with the immunological mechanisms of the brain and can induce disease progression. In this review, we discussed the mechanisms and essential role of inflammatory signaling pathways in AD pathogenesis. Indeed, interfering with immune processes and modulation of risk factors may lead to future therapeutic or preventive AD approaches.
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Affiliation(s)
- Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka. Bangladesh
| | | | - Maroua Jalouli
- College of Science, King Saud University, P.O. Box 2455, Riyadh 11451. Saudi Arabia
| | - Md Ataur Rahman
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul. Korea
| | - Philippe Jeandet
- Research Unit "Induced Resistance and Plant Bioprotection", EA 4707, SFR Condorcet FR CNRS 3417, Faculty of Sciences, University of Reims Champagne-Ardenne, PO Box 1039, 51687 Reims Cedex 2. France
| | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Punjab. India
| | - Athanasios Alexiou
- Novel Global Community Educational Foundation, 2770 Hebersham. Australia
| | - Ghadeer M Albadrani
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11474. Saudi Arabia
| | - Mohamed M Abdel-Daim
- Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522. Egypt
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur. India
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah. Saudi Arabia
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26
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Patel AG, Nehete PN, Krivoshik SR, Pei X, Cho EL, Nehete BP, Ramani MD, Shao Y, Williams LE, Wisniewski T, Scholtzova H. Innate immunity stimulation via CpG oligodeoxynucleotides ameliorates Alzheimer's disease pathology in aged squirrel monkeys. Brain 2021; 144:2146-2165. [PMID: 34128045 PMCID: PMC8502485 DOI: 10.1093/brain/awab129] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/09/2020] [Accepted: 12/17/2020] [Indexed: 11/15/2022] Open
Abstract
Alzheimer's disease is the most common cause of dementia and the only illness among the top 10 causes of death for which there is no disease-modifying therapy. The failure rate of clinical trials is very high, in part due to the premature translation of successful results in transgenic mouse models to patients. Extensive evidence suggests that dysregulation of innate immunity and microglia/macrophages plays a key role in Alzheimer's disease pathogenesis. Activated resident microglia and peripheral macrophages can display protective or detrimental phenotypes depending on the stimulus and environment. Toll-like receptors (TLRs) are a family of innate immune regulators known to play an important role in governing the phenotypic status of microglia. We have shown in multiple transgenic Alzheimer's disease mouse models that harnessing innate immunity via TLR9 agonist CpG oligodeoxynucleotides (ODNs) modulates age-related defects associated with immune cells and safely reduces amyloid plaques, oligomeric amyloid-β, tau pathology, and cerebral amyloid angiopathy (CAA) while promoting cognitive benefits. In the current study we have used a non-human primate model of sporadic Alzheimer's disease pathology that develops extensive CAA-elderly squirrel monkeys. The major complications in current immunotherapeutic trials for Alzheimer's disease are amyloid-related imaging abnormalities, which are linked to the presence and extent of CAA; hence, the prominence of CAA in elderly squirrel monkeys makes them a valuable model for studying the safety of the CpG ODN-based concept of immunomodulation. We demonstrate that long-term use of Class B CpG ODN 2006 induces a favourable degree of innate immunity stimulation without producing excessive or sustained inflammation, resulting in efficient amelioration of both CAA and tau Alzheimer's disease-related pathologies in association with behavioural improvements and in the absence of microhaemorrhages in aged elderly squirrel monkeys. CpG ODN 2006 has been well established in numerous human trials for a variety of diseases. The present evidence together with our earlier, extensive preclinical research, validates the beneficial therapeutic outcomes and safety of this innovative immunomodulatory approach, increasing the likelihood of CpG ODN therapeutic efficacy in future clinical trials.
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Affiliation(s)
- Akash G Patel
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Pramod N Nehete
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Sara R Krivoshik
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Xuewei Pei
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Elizabeth L Cho
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Bharti P Nehete
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Margish D Ramani
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Yongzhao Shao
- Division of Biostatistics, Departments of Population Health and Environmental Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Lawrence E Williams
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Thomas Wisniewski
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Henrieta Scholtzova
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
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27
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Yu TW, Lane HY, Lin CH. Novel Therapeutic Approaches for Alzheimer's Disease: An Updated Review. Int J Mol Sci 2021; 22:ijms22158208. [PMID: 34360973 PMCID: PMC8348485 DOI: 10.3390/ijms22158208] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/25/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disease and accounts for most cases of dementia. The prevalence of AD has increased in the current rapidly aging society and contributes to a heavy burden on families and society. Despite the profound impact of AD, current treatments are unable to achieve satisfactory therapeutic effects or stop the progression of the disease. Finding novel treatments for AD has become urgent. In this paper, we reviewed novel therapeutic approaches in five categories: anti-amyloid therapy, anti-tau therapy, anti-neuroinflammatory therapy, neuroprotective agents including N-methyl-D-aspartate (NMDA) receptor modulators, and brain stimulation. The trend of therapeutic development is shifting from a single pathological target to a more complex mechanism, such as the neuroinflammatory and neurodegenerative processes. While drug repositioning may accelerate pharmacological development, non-pharmacological interventions, especially repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), also have the potential for clinical application. In the future, it is possible for physicians to choose appropriate interventions individually on the basis of precision medicine.
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Affiliation(s)
- Tien-Wei Yu
- Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan;
| | - Hsien-Yuan Lane
- Department of Psychiatry and Brain Disease Research Center, China Medical University Hospital, Taichung 40402, Taiwan
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Department of Psychology, College of Medical and Health Sciences, Asia University, Taichung 41354, Taiwan
- Correspondence: (H.-Y.L.); (C.-H.L.); Tel.: +886-921-067-260 (H.-Y.L.); +886-7-7317123 (ext. 8753) (C.-H.L.); Fax: +886-4-2236-1042 (H.-Y.L.); +886-7-7326817 (C.-H.L.)
| | - Chieh-Hsin Lin
- Department of Psychiatry, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung 83301, Taiwan;
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- School of Medicine, Chang Gung University, Taoyuan 333, Taiwan
- Correspondence: (H.-Y.L.); (C.-H.L.); Tel.: +886-921-067-260 (H.-Y.L.); +886-7-7317123 (ext. 8753) (C.-H.L.); Fax: +886-4-2236-1042 (H.-Y.L.); +886-7-7326817 (C.-H.L.)
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28
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Miller S, Blanco MJ. Small molecule therapeutics for neuroinflammation-mediated neurodegenerative disorders. RSC Med Chem 2021; 12:871-886. [PMID: 34223157 PMCID: PMC8221257 DOI: 10.1039/d1md00036e] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/30/2021] [Indexed: 12/12/2022] Open
Abstract
Chronically activated microglia and the resulting cascade of neuroinflammatory mechanisms have been postulated to play a critical role in neurodegenerative disorders. Microglia are the main component of the brain's innate immune system and become activated by infection, injury, misfolded proteins or a multitude of other stimuli. Activated microglia release pro-inflammatory and cytotoxic factors that can damage neurons and transform astrocytes to become toxic to neurons as well. Therapeutic approaches aiming to modulate microglia activation may be beneficial to mitigate the progression of inflammatory-mediated neurodegenerative diseases. In this literature review, we provide an overview of recent progress on key microglia targets and discovery of small molecule compounds advancing in clinical trials to minimize neuroinflammation.
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Affiliation(s)
- Silke Miller
- Sage Therapeutics, Inc. 215 First Street Cambridge Massachusetts 02142 USA
| | - Maria-Jesus Blanco
- Sage Therapeutics, Inc. 215 First Street Cambridge Massachusetts 02142 USA
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29
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Tedeschi DV, da Cunha AF, Cominetti MR, Pedroso RV. Efficacy of Gene Therapy to Restore Cognition in Alzheimer's Disease: A Systematic Review. Curr Gene Ther 2021; 21:246-257. [PMID: 33494678 DOI: 10.2174/1566523221666210120091146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/09/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is the main cause of dementia and it is a progressive neurogenerative disease characterized by the accumulation of neurofibrillary tangles and senile plaques. There is currently no cure; however, some treatments are available to slow down the progression of the disease, including gene therapy, which has been investigated to have great potential for the treatment of AD. OBJECTIVE The aim of this review was to identify the efficacy of gene therapy to restore cognition in AD. METHODS A systematic review was carried out using papers published up to May 2020 and available in the Web of Science, Scopus, and Medline/PUBMED databases. Articles were considered for inclusion if they were original researches that investigated the effects of gene therapy on cognition in AD. The methodological quality of the selected studies was evaluated using the Risk of Bias Tool for Animal Intervention Studies (SYRCLE's Rob tool) and the Jadad Scale. RESULTS Most preclinical studies obtained positive results in improving memory and learning in mice that underwent treatment with gene therapy. On the other hand, clinical studies have obtained inconclusive results related to the delivery methods of the viral vector used in gene therapy. CONCLUSION Gene therapy has shown a great potential for the treatment of AD in preclinical trials, but results should be interpreted with caution since preclinical studies presented limitations to predict the efficacy of the treatment outcome in humans.
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Affiliation(s)
- Desyrre V Tedeschi
- Federal University of Sao Carlos, Rodovia Washington Luis Km 310 - 13565-905, Sao Carlos SP, Brazil
| | - Anderson F da Cunha
- Department of Genetics and Evolution, Federal University of Sao Carlos, Rodovia Washington Luis Km 310 - 13565- 905, Sao Carlos SP, Brazil
| | - Márcia R Cominetti
- Department of Gerontology, Federal University of Sao Carlos, Rodovia Washington Luis Km 310 - 13565-905, Sao Carlos SP, Brazil
| | - Renata Valle Pedroso
- Department of Gerontology, Federal University of Sao Carlos, Rodovia Washington Luis Km 310 - 13565-905, Sao Carlos SP, Brazil
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30
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Süß P, Schlachetzki JCM. Microglia in Alzheimer's Disease. Curr Alzheimer Res 2021; 17:29-43. [PMID: 32048973 DOI: 10.2174/1567205017666200212155234] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 12/31/2019] [Accepted: 01/20/2020] [Indexed: 11/22/2022]
Abstract
Alzheimer's Disease (AD) is the most frequent neurodegenerative disorder. Although proteinaceous aggregates of extracellular Amyloid-β (Aβ) and intracellular hyperphosphorylated microtubule- associated tau have long been identified as characteristic neuropathological hallmarks of AD, a disease- modifying therapy against these targets has not been successful. An emerging concept is that microglia, the innate immune cells of the brain, are major players in AD pathogenesis. Microglia are longlived tissue-resident professional phagocytes that survey and rapidly respond to changes in their microenvironment. Subpopulations of microglia cluster around Aβ plaques and adopt a transcriptomic signature specifically linked to neurodegeneration. A plethora of molecules and pathways associated with microglia function and dysfunction has been identified as important players in mediating neurodegeneration. However, whether microglia exert either beneficial or detrimental effects in AD pathology may depend on the disease stage. In this review, we summarize the current knowledge about the stage-dependent role of microglia in AD, including recent insights from genetic and gene expression profiling studies as well as novel imaging techniques focusing on microglia in human AD pathology and AD mouse models.
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Affiliation(s)
- Patrick Süß
- Department of Molecular Neurology, University Hospital Erlangen, Friedrich-Alexander-Universitat, Erlangen- Nürnberg, Germany
| | - Johannes C M Schlachetzki
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0651, United States
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31
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Pascual M, Calvo-Rodriguez M, Núñez L, Villalobos C, Ureña J, Guerri C. Toll-like receptors in neuroinflammation, neurodegeneration, and alcohol-induced brain damage. IUBMB Life 2021; 73:900-915. [PMID: 34033211 DOI: 10.1002/iub.2510] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/05/2021] [Accepted: 05/22/2021] [Indexed: 12/12/2022]
Abstract
Toll-like receptors (TLRs) or pattern recognition receptors respond to pathogen-associated molecular patterns (PAMPs) or internal damage-associated molecular patterns (DAMPs). TLRs are integral membrane proteins with both extracellular leucine-rich and cytoplasmic domains that initiate downstream signaling through kinases by activating transcription factors like AP-1 and NF-κB, which lead to the release of various inflammatory cytokines and immune modulators. In the central nervous system, different TLRs are expressed mainly in microglia and astroglial cells, although some TLRs are also expressed in oligodendroglia and neurons. Activation of TLRs triggers signaling cascades by the host as a defense mechanism against invaders to repair damaged tissue. However, overactivation of TLRs disrupts the sustained immune homeostasis-induced production of pro-inflammatory molecules, such as cytokines, miRNAs, and inflammatory components of extracellular vesicles. These inflammatory mediators can, in turn, induce neuroinflammation, and neural tissue damage associated with many neurodegenerative diseases. This review discusses the critical role of TLRs response in Alzheimer's disease, Parkinson's disease, ischemic stroke, amyotrophic lateral sclerosis, and alcohol-induced brain damage and neurodegeneration.
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Affiliation(s)
- María Pascual
- Department of Physiology, School of Medicine and Dentistry, University of Valencia, Valencia, Spain
| | - Maria Calvo-Rodriguez
- Alzheimer's Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Lucía Núñez
- Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and National Research Council (CSIC), Valladolid, Spain.,Department of Biochemistry and Molecular Biology and Physiology, University of Valladolid, Valladolid, Spain
| | - Carlos Villalobos
- Institute of Biology and Molecular Genetics (IBGM), University of Valladolid and National Research Council (CSIC), Valladolid, Spain
| | - Juan Ureña
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain
| | - Consuelo Guerri
- Department of Molecular and Cellular Pathology of Alcohol, Príncipe Felipe Research Center, Valencia, Spain
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32
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Qiao O, Ji H, Zhang Y, Zhang X, Zhang X, Liu N, Huang L, Liu C, Gao W. New insights in drug development for Alzheimer's disease based on microglia function. Biomed Pharmacother 2021; 140:111703. [PMID: 34083109 DOI: 10.1016/j.biopha.2021.111703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/29/2021] [Accepted: 05/05/2021] [Indexed: 12/26/2022] Open
Abstract
One of the biggest challenges in drug development for Alzheimer's disease (AD) is how to effectively remove deposits of amyloid-beta (Aβ). Recently, the relationship between microglia and Aβ has become a research hotspot. Emerging evidence suggests that Aβ-induced microglia-mediated neuroinflammation further aggravates the decline of cognitive function, while microglia are also involved in the process of Aβ clearance. Hence, microglia have become a potential therapeutic target for the treatment or prevention of AD. An in-depth understanding of the role played by microglia in the development of AD will help us to broaden therapeutic strategies for AD. In this review, we provide an overview of the dual roles of microglia in AD progression: the positive effect of phagocytosis of Aβ and its negative effect on neuroinflammation after over-activation. With the advantages of novel structure, high efficiency, and low toxicity, small-molecule compounds as modulators of microglial function have attracted considerable attention in the therapeutic areas of AD. In this review, we also summarize the therapeutic potential of small molecule compounds (SMCs) and their structure-activity relationship for AD treatment through modulating microglial phagocytosis and inhibiting neuroinflammation. For example, the position and number of phenolic hydroxyl groups on the B ring are the key to the activity of flavonoids, and the substitution of hydroxyl groups on the benzene ring enhances the anti-inflammatory activity of phenolic acids. This review is expected to be useful for developing effective modulators of microglial function from SMCs for the amelioration and treatment of AD.
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Affiliation(s)
- Ou Qiao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Haixia Ji
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Yi Zhang
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Xinyu Zhang
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Xueqian Zhang
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Na Liu
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China
| | - Luqi Huang
- Chinese Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Changxiao Liu
- The State Key Laboratories of Pharmacodynamics and Pharmacokinetics, Tianjin 300193, China
| | - Wenyuan Gao
- Tianjin Key Laboratory for Modern Drug Delivery and High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Weijin Road, Tianjin 300072, China.
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33
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Duggan MR, Parikh V. Microglia and modifiable life factors: Potential contributions to cognitive resilience in aging. Behav Brain Res 2021; 405:113207. [PMID: 33640394 PMCID: PMC8005490 DOI: 10.1016/j.bbr.2021.113207] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/27/2021] [Accepted: 02/20/2021] [Indexed: 02/08/2023]
Abstract
Given the increasing prevalence of age-related cognitive decline, it is relevant to consider the factors and mechanisms that might facilitate an individual's resiliency to such deficits. Growing evidence suggests a preeminent role of microglia, the prime mediator of innate immunity within the central nervous system. Human and animal investigations suggest aberrant microglial functioning and neuroinflammation are not only characteristic of the aged brain, but also might contribute to age-related dementia and Alzheimer's Disease. Conversely, accumulating data suggest that modifiable lifestyle factors (MLFs), such as healthy diet, exercise and cognitive engagement, can reliably afford cognitive benefits by potentially suppressing inflammation in the aging brain. The present review highlights recent advances in our understanding of the role for microglia in maintaining brain homeostasis and cognitive functioning in aging. Moreover, we propose an integrated, mechanistic model that postulates an individual's resiliency to cognitive decline afforded by MLFs might be mediated by the mitigation of aberrant microglia activation in aging, and subsequent suppression of neuroinflammation.
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Affiliation(s)
- Michael R Duggan
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, United States
| | - Vinay Parikh
- Department of Psychology and Neuroscience Program, Temple University, Philadelphia, PA, 19122, United States.
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34
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Sarno E, Moeser AJ, Robison AJ. Neuroimmunology of depression. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 91:259-292. [PMID: 34099111 DOI: 10.1016/bs.apha.2021.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Depression is one of the leading causes of disability worldwide and a major contributor to the global burden of disease, yet the cellular and molecular etiology of depression remain largely unknown. Major Depressive Disorder (MDD) is associated with a variety of chronic physical inflammatory and autoimmune disorders, and mood disorders may act synergistically with other medical disorders to worsen patient outcomes. Here, we outline the neuroimmune complement, explore the evidence for altered immune system function in MDD, and present some of the potential mechanisms by which immune cells and molecules may drive the onset and course of MDD. These include pro-inflammatory signaling, alterations in the hypothalamic-pituitary-adrenal axis, dysregulation of the serotonergic and noradrenergic neurotransmitter systems, neuroinflammation, and meningeal immune dysfunction. Finally, we discuss the interactions between current antidepressants and the immune system and propose the possibility of immunomodulatory drugs as potential novel antidepressant treatments.
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Affiliation(s)
- Erika Sarno
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Adam J Moeser
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, United States
| | - Alfred J Robison
- Department of Physiology, Michigan State University, East Lansing, MI, United States.
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35
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Ernest James Phillips T, Maguire E. Phosphoinositides: Roles in the Development of Microglial-Mediated Neuroinflammation and Neurodegeneration. Front Cell Neurosci 2021; 15:652593. [PMID: 33841102 PMCID: PMC8032904 DOI: 10.3389/fncel.2021.652593] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
Microglia are increasingly recognized as vital players in the pathology of a variety of neurodegenerative conditions including Alzheimer’s (AD) and Parkinson’s (PD) disease. While microglia have a protective role in the brain, their dysfunction can lead to neuroinflammation and contributes to disease progression. Also, a growing body of literature highlights the seven phosphoinositides, or PIPs, as key players in the regulation of microglial-mediated neuroinflammation. These small signaling lipids are phosphorylated derivates of phosphatidylinositol, are enriched in the brain, and have well-established roles in both homeostasis and disease.Disrupted PIP levels and signaling has been detected in a variety of dementias. Moreover, many known AD disease modifiers identified via genetic studies are expressed in microglia and are involved in phospholipid metabolism. One of these, the enzyme PLCγ2 that hydrolyzes the PIP species PI(4,5)P2, displays altered expression in AD and PD and is currently being investigated as a potential therapeutic target.Perhaps unsurprisingly, neurodegenerative conditions exhibiting PIP dyshomeostasis also tend to show alterations in aspects of microglial function regulated by these lipids. In particular, phosphoinositides regulate the activities of proteins and enzymes required for endocytosis, toll-like receptor signaling, purinergic signaling, chemotaxis, and migration, all of which are affected in a variety of neurodegenerative conditions. These functions are crucial to allow microglia to adequately survey the brain and respond appropriately to invading pathogens and other abnormalities, including misfolded proteins. AD and PD therapies are being developed to target many of the above pathways, and although not yet investigated, simultaneous PIP manipulation might enhance the beneficial effects observed. Currently, only limited therapeutics are available for dementia, and although these show some benefits for symptom severity and progression, they are far from curative. Given the importance of microglia and PIPs in dementia development, this review summarizes current research and asks whether we can exploit this information to design more targeted, or perhaps combined, dementia therapeutics. More work is needed to fully characterize the pathways discussed in this review, but given the strength of the current literature, insights in this area could be invaluable for the future of neurodegenerative disease research.
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Affiliation(s)
| | - Emily Maguire
- UK Dementia Research Institute at Cardiff University, Cardiff, United Kingdom
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Öberg M, Fabrik I, Fabrikova D, Zehetner N, Härtlova A. The role of innate immunity and inflammation in Parkinson´s disease. Scand J Immunol 2021; 93:e13022. [PMID: 33471378 DOI: 10.1111/sji.13022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 11/08/2020] [Accepted: 01/17/2021] [Indexed: 01/09/2023]
Abstract
For many years, it was postulated that the brain is the organ behind the barrier with an autonomous need for its maintenance. This view has been changed by the concept that the central nervous system is sensitive to the immune processes occurring in the periphery as well as to the infiltration of peripheral immune cells. However, how the immune system might contribute to the development of neurodegenerative diseases, such as Parkinson's disease (PD), remains unclear. PD is a chronic neurodegenerative disorder that affects motor and cognitive functions. Although the precise cause of PD is unknown, studies in both mice and human suggest that alterations in the innate immunity may play a critical role in modulating PD progression. Here, we review recent advancements in our understanding of inflammation and the innate immune mechanisms in PD pathology.
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Affiliation(s)
- Maria Öberg
- Wallenberg Centre for Molecular and Translational Medicine, Department of Microbiology and Immunology at Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Ivo Fabrik
- Wallenberg Centre for Molecular and Translational Medicine, Department of Microbiology and Immunology at Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Daniela Fabrikova
- Wallenberg Centre for Molecular and Translational Medicine, Department of Microbiology and Immunology at Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Nina Zehetner
- Wallenberg Centre for Molecular and Translational Medicine, Department of Microbiology and Immunology at Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Anetta Härtlova
- Wallenberg Centre for Molecular and Translational Medicine, Department of Microbiology and Immunology at Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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Chen SH, Tian DY, Shen YY, Cheng Y, Fan DY, Sun HL, He CY, Sun PY, Bu XL, Zeng F, Liu J, Deng J, Xu ZQ, Chen Y, Wang YJ. Amyloid-beta uptake by blood monocytes is reduced with ageing and Alzheimer's disease. Transl Psychiatry 2020; 10:423. [PMID: 33293506 PMCID: PMC7722845 DOI: 10.1038/s41398-020-01113-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/07/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
Deficits in the clearance of amyloid β-protein (Aβ) play a pivotal role in the pathogenesis of sporadic Alzheimer's disease (AD). The roles of blood monocytes in the development of AD remain unclear. In this study, we sought to investigate the alterations in the Aβ phagocytosis function of peripheral monocytes during ageing and in AD patients. A total of 104 cognitively normal participants aged 22-89 years, 24 AD patients, 25 age- and sex-matched cognitively normal (CN) subjects, 15 Parkinson's disease patients (PD), and 15 age- and sex-matched CN subjects were recruited. The Aβ uptake by blood monocytes was measured and its alteration during ageing and in AD patients were investigated. Aβ1-42 uptake by monocytes decreased during ageing and further decreased in AD but not in PD patients. Aβ1-42 uptake by monocytes was associated with Aβ1-42 levels in the blood. Among the Aβ uptake-related receptors and enzymes, the expression of Toll-like receptor 2 (TLR2) was reduced in monocytes from AD patients. Our findings suggest that monocytes regulate the blood levels of Aβ and might be involved in the development of AD. The recovery of the Aβ uptake function by blood monocytes represents a potential therapeutic strategy for AD.
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Affiliation(s)
- Si-Han Chen
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Ding-Yuan Tian
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Ying-Ying Shen
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Yuan Cheng
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Dong-Yu Fan
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Hao-Lun Sun
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Chen-Yang He
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Pu-Yang Sun
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Xian-Le Bu
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Fan Zeng
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Juan Liu
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Juan Deng
- grid.410570.70000 0004 1760 6682Department of Health Management, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Zhi-Qiang Xu
- grid.410570.70000 0004 1760 6682Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China ,grid.410570.70000 0004 1760 6682The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China ,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China
| | - Yang Chen
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China. .,The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China. .,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China.
| | - Yan-Jiang Wang
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China. .,The Institute of Brain and Intelligence, Third Military Medical University, Chongqing, China. .,Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, China. .,State Key Laboratory of Trauma, Burn and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing, China. .,Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
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Miyanishi K, Sato A, Kihara N, Utsunomiya R, Tanaka J. Synaptic elimination by microglia and disturbed higher brain functions. Neurochem Int 2020; 142:104901. [PMID: 33181238 DOI: 10.1016/j.neuint.2020.104901] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/28/2020] [Accepted: 11/04/2020] [Indexed: 12/25/2022]
Abstract
Microglial cells in normal mature brains have long been considered to be cells that are resting until pathological events take place, activating the microglial cells. However, it is currently well known that the microglia that have resting ramified morphology in normal mature brains move actively in the brain parenchyma and phagocytose synapses, thus forming and maintaining neural circuits. This review summarizes recent findings on the roles of microglia in mature brains, with special reference to phagocytosis of synapses and higher brain functions. Phagocytic elimination of synapses by microglia may affect the balance between excitatory and inhibitory synaptic transmission, termed the E/I balance. When impaired synaptic elimination by microglia leads to disturbed E/I balance, various problems may follow in brain functions: in memory and cognitive functions, sleep, movement, social behaviors, and thinking. In addition to the roles of microglia in normal developing and mature brains, impaired microglial phagocytosis functions also correlate with disturbances to these higher brain functions that are caused by neurological, mental, and developmental disorders; Parkinson's and Alzheimer's diseases, autism spectrum disorder, attention deficit/hyperactivity disorder, and schizophrenia.
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Affiliation(s)
- Kazuya Miyanishi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Arisa Sato
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Nanako Kihara
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Ryo Utsunomiya
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan
| | - Junya Tanaka
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan.
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39
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Toll-like receptors in Alzheimer's disease. J Neuroimmunol 2020; 348:577362. [DOI: 10.1016/j.jneuroim.2020.577362] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/04/2020] [Accepted: 08/15/2020] [Indexed: 02/07/2023]
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Medina-Rodriguez EM, Cheng Y, Michalek SM, Beurel E, Jope RS. Toll-like receptor 2 (TLR2)-deficiency impairs male mouse recovery from a depression-like state. Brain Behav Immun 2020; 89:51-58. [PMID: 32479995 PMCID: PMC7572513 DOI: 10.1016/j.bbi.2020.05.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 02/07/2023] Open
Abstract
Major depression is a prevalent, debilitating disease, yet therapeutic interventions for depression are frequently inadequate. Many clinical and pre-clinical studies have demonstrated that depression is associated with aberrant activation of the inflammatory system, raising the possibility that reducing inflammation may provide antidepressant effects. Using the learned helplessness mouse model, we tested if susceptibility or recovery were affected by deficiency in either of two receptors that initiate inflammatory signaling, Toll-like receptor-4 (TLR4) and TLR2, using knockout male mice. TLR4-/- mice displayed a strong resistance to learned helplessness, confirming that blocking inflammatory signaling through TLR4 provides robust protection against this depression-like behavior. Surprisingly, TLR2-/- mice displayed increased susceptibility to learned helplessness, indicating that TLR2-mediated signaling counteracts susceptibility. TLR2-mediated signaling also promotes recovery, as TLR2-/- mice demonstrated a severe impairment in recovery from learned helplessness. That TLR2 actually protects from learned helplessness was further verified by the finding that administration of the TLR2 agonist Pam3CSK4 reduced susceptibility to learned helplessness. Treatment with Pam3CSK4 also reversed chronic restraint stress-induced impaired sociability and impaired learning in the novel object recognition paradigm, demonstrating that TLR2 stimulation can protect from multiple impairments caused by stress. In summary, these results demonstrate that TLR2-mediated signaling provides a counter-signal to oppose deleterious effects of stress that may be related to depression, and indicate that TLR2 and TLR4 act oppositely to balance mood-relevant responses to stress.
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Affiliation(s)
- Eva M Medina-Rodriguez
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL 33136, United States; Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL 33125, United States
| | - Yuyan Cheng
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, United States
| | - Suzanne M Michalek
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294-0017, United States
| | - Eléonore Beurel
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL 33136, United States; Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, United States.
| | - Richard S Jope
- Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL 33136, United States; Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL 33125, United States; Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL 33136, United States
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Wang H, Shen Y, Chuang H, Chiu C, Ye Y, Zhao L. Neuroinflammation in Alzheimer's Disease: Microglia, Molecular Participants and Therapeutic Choices. Curr Alzheimer Res 2020; 16:659-674. [PMID: 31580243 DOI: 10.2174/1567205016666190503151648] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 03/21/2019] [Accepted: 04/30/2019] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease is the world's most common dementing illness. It is pathologically characterized by β-amyloid accumulation, extracellular senile plaques and intracellular neurofibrillary tangles formation, and neuronal necrosis and apoptosis. Neuroinflammation has been widely recognized as a crucial process that participates in AD pathogenesis. In this review, we briefly summarized the involvement of microglia in the neuroinflammatory process of Alzheimer's disease. Its roles in the AD onset and progression are also discussed. Numerous molecules, including interleukins, tumor necrosis factor alpha, chemokines, inflammasomes, participate in the complex process of AD-related neuroinflammation and they are selectively discussed in this review. In the end of this paper from an inflammation- related perspective, we discussed some potential therapeutic choices.
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Affiliation(s)
- Haijun Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yin Shen
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Haoyu Chuang
- Department of Neurosurgery, Tainan Municipal An-Nan Hospital, Tainan, Taiwan.,Department of Neurosurgery, China Medical University Bei-Gang Hospital, Yun-Lin, Taiwan.,School of Medicine, China Medical University, Taichung, Taiwan
| | - Chengdi Chiu
- School of Medicine, China Medical University, Taichung, Taiwan.,Department of Neurosurgery, China Medical University Hospital, Taichung, Taiwan
| | - Youfan Ye
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lei Zhao
- Department of Infectious Disease, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
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Ennerfelt HE, Lukens JR. The role of innate immunity in Alzheimer's disease. Immunol Rev 2020; 297:225-246. [PMID: 32588460 PMCID: PMC7783860 DOI: 10.1111/imr.12896] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022]
Abstract
The amyloid hypothesis has dominated Alzheimer's disease (AD) research for almost 30 years. This hypothesis hinges on the predominant clinical role of the amyloid beta (Aβ) peptide in propagating neurofibrillary tangles (NFTs) and eventual cognitive impairment in AD. Recent research in the AD field has identified the brain-resident macrophages, known as microglia, and their receptors as integral regulators of both the initiation and propagation of inflammation, Aβ accumulation, neuronal loss, and memory decline in AD. Emerging studies have also begun to reveal critical roles for distinct innate immune pathways in AD pathogenesis, which has led to great interest in harnessing the innate immune response as a therapeutic strategy to treat AD. In this review, we will highlight recent advancements in our understanding of innate immunity and inflammation in AD onset and progression. Additionally, there has been mounting evidence suggesting pivotal contributions of environmental factors and lifestyle choices in AD pathogenesis. Therefore, we will also discuss recent findings, suggesting that many of these AD risk factors influence AD progression via modulation of microglia and immune responses.
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Affiliation(s)
- Hannah E. Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - John R. Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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Microglia Do Not Take Up Soluble Amyloid-beta Peptides, But Partially Degrade Them by Secreting Insulin-degrading Enzyme. Neuroscience 2020; 443:30-43. [PMID: 32697980 DOI: 10.1016/j.neuroscience.2020.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/03/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022]
Abstract
Microglia play important roles in the pathogenesis of Alzheimer's disease (AD), in part, by affecting the clearance of amyloid-β (Aβ) peptides. Most studies, however, used synthetic soluble Aβ (sAβ) at higher concentrations. The exact mechanisms underlying microglia-mediated clearance of physiological sAβ at very low concentrations remain unclear. Here we reported that there were much more Iba-1- and CD68-positive microglia and significantly less sAβ left in the brain of adult mice 5 days after the surgery of sAβ microinjection compared to 2 h after the surgery (p < 0.05). However, very few Iba-1- and CD68-positive microglia co-localized with microinjected fluorescently labeled sAβ (FLsAβ42) 5 days after the surgery. Also, there was no co-localization of FLsAβ42 with a lysosomal marker (LAMP-1) 5 days after the surgery. There was no significant difference in the percentage of Aβ+/PE-CD11b+/APC-CD45low microglia between the control group and the group microinjected with TBS-soluble Aβ extracted from the brains of AD patients (p > 0.05). The degradation of physiological sAβ was prevented by a highly selective insulin-degrading enzyme inhibitor (Ii1) but not by a phagocytosis inhibitor (polyinosinic acid) or pinocytosis inhibitor (cytochalasin B) in vitro. Furthermore, the reduction of synthetic and physiological sAβ in the brain was partially prevented by the co-injection of Ii1 in vivo (p < 0.05). Our results demonstrate that microglia do not take up synthetic or physiological sAβ, but partially degrade it via the secretion of insulin-degrading enzyme, which will be beneficial for understanding how sAβ is removed from the brain by microglia.
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Capturing Amyloid-β Oligomers by Stirring with Microscaled Iron Oxide Stir Bars into Magnetic Plaques to Reduce Cytotoxicity toward Neuronal Cells. NANOMATERIALS 2020; 10:nano10071284. [PMID: 32629933 PMCID: PMC7407479 DOI: 10.3390/nano10071284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/24/2020] [Accepted: 06/28/2020] [Indexed: 11/17/2022]
Abstract
Soluble amyloid-β oligomers (oAβ42)-induced neuronal death and inflammation response has been recognized as one of the major causes of Alzheimer’s disease (AD). In this work, a novel strategy adopting silica-coated iron oxide stir bar (MSB)-based AD therapy system via magnetic stirring-induced capture of oAβ42 into magnetic plaques (mpAβ42) and activation of microglia on cellular plaque clearance was developed. With oAβ42 being effectively converted into mpAβ42, the neurotoxicity toward neuronal cells was thus greatly reduced. In addition to the good preservation of neurite outgrowth through the diminished uptake of oAβ42, neurons treated with oAβ42 under magnetic stirring also exhibited comparable neuron-specific protein expression to those in the absence of oAβ42. The phagocytic uptake of mpAβ42 by microglia was enhanced significantly as compared to the counterpart of oAβ42, and the M1 polarization of microglia often occurring after the uptake of oAβ42 restricted to an appreciable extent. As a result, the inflammation induced by pro-inflammatory cytokines was greatly alleviated.
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Yang J, Wise L, Fukuchi KI. TLR4 Cross-Talk With NLRP3 Inflammasome and Complement Signaling Pathways in Alzheimer's Disease. Front Immunol 2020; 11:724. [PMID: 32391019 PMCID: PMC7190872 DOI: 10.3389/fimmu.2020.00724] [Citation(s) in RCA: 177] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/30/2020] [Indexed: 01/02/2023] Open
Abstract
Amyloid plaques, mainly composed of abnormally aggregated amyloid β-protein (Aβ) in the brain parenchyma, and neurofibrillary tangles (NFTs), consisting of hyperphosphorylated tau protein aggregates in neurons, are two pathological hallmarks of Alzheimer's disease (AD). Aβ fibrils and tau aggregates in the brain are closely associated with neuroinflammation and synapse loss, characterized by activated microglia and dystrophic neurites. Genome-wide genetic association studies revealed important roles of innate immune cells in the pathogenesis of late-onset AD by recognizing a dozen genetic risk loci that modulate innate immune activities. Furthermore, microglia, brain resident innate immune cells, have been increasingly recognized to play key, opposing roles in AD pathogenesis by either eliminating toxic Aβ aggregates and enhancing neuronal plasticity or producing proinflammatory cytokines, reactive oxygen species, and synaptotoxicity. Aggregated Aβ binds to toll-like receptor 4 (TLR4) and activates microglia, resulting in increased phagocytosis and cytokine production. Complement components are associated with amyloid plaques and NFTs. Aggregated Aβ can activate complement, leading to synapse pruning and loss by microglial phagocytosis. Systemic inflammation can activate microglial TLR4, NLRP3 inflammasome, and complement in the brain, leading to neuroinflammation, Aβ accumulation, synapse loss and neurodegeneration. The host immune response has been shown to function through complex crosstalk between the TLR, complement and inflammasome signaling pathways. Accordingly, targeting the molecular mechanisms underlying the TLR-complement-NLRP3 inflammasome signaling pathways can be a preventive and therapeutic approach for AD.
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Affiliation(s)
- Junling Yang
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Leslie Wise
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
| | - Ken-Ichiro Fukuchi
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL, United States
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Lax N, Fainstein N, Nishri Y, Ben-Zvi A, Ben-Hur T. Systemic microbial TLR2 agonists induce neurodegeneration in Alzheimer's disease mice. J Neuroinflammation 2020; 17:55. [PMID: 32059733 PMCID: PMC7023749 DOI: 10.1186/s12974-020-01738-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Accumulating data suggest a central role for brain microglia in mediating cortical neuronal death in Alzheimer's disease (AD), and for Toll-like receptor 2 (TLR2) in their toxic activation. Amyloid deposition in preclinical AD is associated with microglial activation but not directly with neurodegeneration. We examined in transgenic 5xFAD mice the hypothesis that systemic TLR2 agonists, derived from common infectious agents, may accelerate neurodegeneration in AD. METHODS Microbial wall-derived TLR2 agonists zymosan and lipoteichoic acid were administered intraperitoneally or intracerebroventricularly to 7-month-old wild-type or 5xFAD mice. Immunofluorescent stainings were used to quantify cortical neurons and evaluate tissue reaction. Microglial activation was assessed using functional assays, RNA expression, and FACS analysis. RESULTS Repeated low-dose systemic administration of zymosan or lipoteichoic acid killed cortical neurons in 5xFAD mice but not in wild-type mice. Direct CNS delivery of a selective TLR2 antagonist blocked the neurotoxicity of systemically administered zymosan, indicating that CNS TLR2 mediates this effect. Systemically administered zymosan crossed the disrupted blood-brain barrier in 5xFAD mice and entered brain parenchyma. By intracerebroventricular delivery, we found a dose- and exposure time-dependent acute neurotoxic effect of the microbial TLR2 agonist, killing cortical neurons. 5xFAD mice exhibited significantly increased vulnerability to TLR2 agonist-induced neuronal loss as compared to wild-type mice. Microbial TLR2-induced neurodegeneration was abolished by inhibiting microglia. The vulnerability of 5xFAD mice brains was mediated by an increase in number and neurotoxic phenotype of TLR2-expressing microglia. CONCLUSIONS We suggest that repeated exposure to microbial TLR2 agonists may facilitate neurodegeneration in AD by their microglial-mediated toxicity to the hyper-vulnerable environment of the AD brain.
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Affiliation(s)
- Neta Lax
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Nina Fainstein
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Yossi Nishri
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel
| | - Ayal Ben-Zvi
- Department of Developmental Biology and Cancer Research, Institute of Medical Research Israel-Canada, Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Tamir Ben-Hur
- Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah - Hebrew University Medical Center, Jerusalem, Israel.
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Li S, Hayden EY, Garcia VJ, Fuchs DT, Sheyn J, Daley DA, Rentsendorj A, Torbati T, Black KL, Rutishauser U, Teplow DB, Koronyo Y, Koronyo-Hamaoui M. Activated Bone Marrow-Derived Macrophages Eradicate Alzheimer's-Related Aβ 42 Oligomers and Protect Synapses. Front Immunol 2020; 11:49. [PMID: 32082319 PMCID: PMC7005081 DOI: 10.3389/fimmu.2020.00049] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/09/2020] [Indexed: 12/13/2022] Open
Abstract
Impaired synaptic integrity and function due to accumulation of amyloid β-protein (Aβ42) oligomers is thought to be a major contributor to cognitive decline in Alzheimer's disease (AD). However, the exact role of Aβ42 oligomers in synaptotoxicity and the ability of peripheral innate immune cells to rescue synapses remain poorly understood due to the metastable nature of oligomers. Here, we utilized photo-induced cross-linking to stabilize pure oligomers and study their effects vs. fibrils on synapses and protection by Aβ-phagocytic macrophages. We found that cortical neurons were more susceptible to Aβ42 oligomers than fibrils, triggering additional neuritic arborization retraction, functional alterations (hyperactivity and spike waveform), and loss of VGluT1- and PSD95-excitatory synapses. Co-culturing neurons with bone marrow-derived macrophages protected synapses against Aβ42 fibrils; moreover, immune activation with glatiramer acetate (GA) conferred further protection against oligomers. Mechanisms involved increased Aβ42 removal by macrophages, amplified by GA stimulation: fibrils were largely cleared through intracellular CD36/EEA1+-early endosomal proteolysis, while oligomers were primarily removed via extracellular/MMP-9 enzymatic degradation. In vivo studies in GA-immunized or CD115+-monocyte-grafted APPSWE/PS1ΔE9-transgenic mice followed by pre- and postsynaptic analyses of entorhinal cortex and hippocampal substructures corroborated our in vitro findings of macrophage-mediated synaptic preservation. Together, our data demonstrate that activated macrophages effectively clear Aβ42 oligomers and rescue VGluT1/PSD95 synapses, providing rationale for harnessing macrophages to treat AD.
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Affiliation(s)
- Songlin Li
- Institute of Neuroscience and Chemistry, Wenzhou University, Wenzhou, China
- Institute of Life Sciences, Wenzhou University, Wenzhou, China
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Eric Y. Hayden
- Department of Neurology, David Geffen School of Medicine at UCLA, Mary S. Easton Center for Alzheimer's Disease Research at UCLA, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Veronica J. Garcia
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Julia Sheyn
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - David A. Daley
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Altan Rentsendorj
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Tania Torbati
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, United States
| | - Keith L. Black
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - David B. Teplow
- Department of Neurology, David Geffen School of Medicine at UCLA, Mary S. Easton Center for Alzheimer's Disease Research at UCLA, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Yosef Koronyo
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Cedars-Sinai Medical Center, Maxine-Dunitz Neurosurgical Institute, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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48
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Genetic Dissection of Alzheimer's Disease Using Drosophila Models. Int J Mol Sci 2020; 21:ijms21030884. [PMID: 32019113 PMCID: PMC7037931 DOI: 10.3390/ijms21030884] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 01/26/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer’s disease (AD), a main cause of dementia, is the most common neurodegenerative disease that is related to abnormal accumulation of the amyloid β (Aβ) protein. Despite decades of intensive research, the mechanisms underlying AD remain elusive, and the only available treatment remains symptomatic. Molecular understanding of the pathogenesis and progression of AD is necessary to develop disease-modifying treatment. Drosophila, as the most advanced genetic model, has been used to explore the molecular mechanisms of AD in the last few decades. Here, we introduce Drosophila AD models based on human Aβ and summarize the results of their genetic dissection. We also discuss the utility of functional genomics using the Drosophila system in the search for AD-associated molecular mechanisms in the post-genomic era.
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Li C, Chen YH, Zhang K. Neuroprotective Properties and Therapeutic Potential of Bone Marrow-Derived Microglia in Alzheimer's Disease. Am J Alzheimers Dis Other Demen 2020; 35:1533317520927169. [PMID: 32536247 PMCID: PMC10623913 DOI: 10.1177/1533317520927169] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, which is characterized by a progressive cognitive decline and senile plaques formed by amyloid β (Aβ). Microglia are the immune cells of the central nervous system (CNS). Studies have proposed 2 types of microglia, namely, the resident microglia and bone marrow-derived microglia (BMDM). Recent studies suggested that BMDM, not the resident microglia, can phagocytose Aβ, which has a great therapeutic potential in AD. Bone marrow-derived microglia can populate the CNS in an efficient manner and their functions can be regulated by some genes. Thus, methods that increase their recruitment and phagocytosis could be used as a new tool that clears Aβ and ameliorates cognitive impairment. Herein, we review the neuroprotective functions of BMDM and their therapeutic potential in AD.
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Affiliation(s)
- Chang Li
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
- Department of Anesthesiology, Shengjing Hospital, China Medical University, Shenyang, China
| | - Yu-Hua Chen
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Ke Zhang
- Department of Developmental Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
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50
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Madadi S, Schwarzenbach H, Saidijam M, Mahjub R, Soleimani M. Potential microRNA-related targets in clearance pathways of amyloid-β: novel therapeutic approach for the treatment of Alzheimer's disease. Cell Biosci 2019; 9:91. [PMID: 31749959 PMCID: PMC6852943 DOI: 10.1186/s13578-019-0354-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023] Open
Abstract
Imbalance between amyloid-beta (Aβ) peptide synthesis and clearance results in Aβ deregulation. Failure to clear these peptides appears to cause the development of Alzheimer's disease (AD). In recent years, microRNAs have become established key regulators of biological processes that relate among others to the development and progression of neurodegenerative diseases, such as AD. This review article gives an overview on microRNAs that are involved in the Aβ cascade and discusses their inhibitory impact on their target mRNAs whose products participate in Aβ clearance. Understanding of the mechanism of microRNA in the associated signal pathways could identify novel therapeutic targets for the treatment of AD.
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Affiliation(s)
- Soheil Madadi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Heidi Schwarzenbach
- Department of Tumor Biology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Massoud Saidijam
- Department of Genetics and Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reza Mahjub
- Department of Pharmaceutics, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Meysam Soleimani
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Hamadan University of Medical Sciences, Hamadan, Iran
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