201
|
Ferri E, Rossi PD, Geraci A, Ciccone S, Cesari M, Arosio B. The sTREM2 Concentrations in the Blood: A Marker of Neurodegeneration? Front Mol Biosci 2021; 7:627931. [PMID: 33768114 PMCID: PMC7985346 DOI: 10.3389/fmolb.2020.627931] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022] Open
Abstract
Microglia performs a variety of functions during brain development designed to maintain brain homeostasis. Triggering receptor expressed on myeloid cells 2 (TREM2) is expressed in microglial cells modulating phagocytosis, cytokine production, cell proliferation, and cell survival. Interestingly, the levels of soluble TREM2 (the secreted ectodomain of TREM2, sTREM2) were higher in cerebrospinal fluid (CSF) from Alzheimer's disease (AD) patients than subjects without cognitive decline. It is noteworthy that, while CSF sTREM2 levels have been extensively studied, few studies have investigated sTREM2 in blood producing conflicting results. We aimed to investigate the levels of sTREM2 in CSF and blood from a cohort of well-characterized AD comparing the results to those obtained in patients suffering from idiopathic normal pressure hydrocephalus (iNPH), a potentially reversible cognitive impairment. Our findings underlined a significantly lower plasma sTREM2 concentration in AD patients compared to iNPH subjects [39.1 ng/mL (standard deviation (SD), 15.0) and 47.2 ng/mL (SD, 19.5), respectively; p = 0.01], whereas no difference was revealed between the two groups in the CSF sTREM2 levels. The adjusted regression analyses evidenced in AD patients an association between plasma and CSF sTREM2 levels [B = 0.411; 95% confidence interval (CI), 0.137-0.685, p = 0.004], as well as β-amyloid concentrations (B = 0.035; 95% CI, 0.007-0.063, p = 0.01) and an association between CSF sTREM2 and phospho-Tau concentrations (B = 0.248; 95% CI, 0.053-0.443; p = 0.01). No significant relation was found in iNPH patients. In conclusion, these differences in sTREM2 profiles between AD and iNPH reinforce the notion that this receptor has a role in neurodegeneration.
Collapse
Affiliation(s)
- Evelyn Ferri
- Geriatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Paolo Dionigi Rossi
- Geriatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Annalisa Geraci
- Geriatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Simona Ciccone
- Geriatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Matteo Cesari
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.,Geriatric Unit, IRCCS Istituti Clinici Scientifici Maugeri, Milan, Italy
| | - Beatrice Arosio
- Geriatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| |
Collapse
|
202
|
Zhang C, Yang M, Ericsson AC. Function of Macrophages in Disease: Current Understanding on Molecular Mechanisms. Front Immunol 2021; 12:620510. [PMID: 33763066 PMCID: PMC7982479 DOI: 10.3389/fimmu.2021.620510] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/17/2021] [Indexed: 12/11/2022] Open
Abstract
Tissue-resident macrophages (TRMs) are heterogeneous populations originating either from monocytes or embryonic progenitors, and distribute in lymphoid and non-lymphoid tissues. TRMs play diverse roles in many physiological processes, including metabolic function, clearance of cellular debris, and tissue remodeling and defense. Macrophages can be polarized to different functional phenotypes depending on their origin and tissue microenvironment. Specific macrophage subpopulations are associated with disease progression. In studies of fate-mapping and single-cell RNA sequencing methodologies, several critical molecules have been identified to induce the change of macrophage function. These molecules are potential markers for diagnosis and selective targets for novel macrophage-mediated treatment. In this review, we discuss some of the recent findings regarding less-known molecules and new functions of well-known molecules. Understanding the mechanisms of these molecules in macrophages has the potential to yield new macrophage-mediated treatments or diagnostic approaches to disease.
Collapse
Affiliation(s)
- Chunye Zhang
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, United States
| | - Ming Yang
- Department of Surgery, University of Missouri, Columbia, MO, United States
| | - Aaron C Ericsson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, United States.,Department of Veterinary Pathobiology, University of Missouri Metagenomics Center, University of Missouri, Columbia, MO, United States.,Department of Veterinary Pathobiology, University of Missouri Mutant Mouse Resource and Research Center, Columbia, MO, United States
| |
Collapse
|
203
|
Ivan DC, Walthert S, Berve K, Steudler J, Locatelli G. Dwellers and Trespassers: Mononuclear Phagocytes at the Borders of the Central Nervous System. Front Immunol 2021; 11:609921. [PMID: 33746939 PMCID: PMC7973121 DOI: 10.3389/fimmu.2020.609921] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/29/2020] [Indexed: 01/02/2023] Open
Abstract
The central nervous system (CNS) parenchyma is enclosed and protected by a multilayered system of cellular and acellular barriers, functionally separating glia and neurons from peripheral circulation and blood-borne immune cells. Populating these borders as dynamic observers, CNS-resident macrophages contribute to organ homeostasis. Upon autoimmune, traumatic or neurodegenerative inflammation, these phagocytes start playing additional roles as immune regulators contributing to disease evolution. At the same time, pathological CNS conditions drive the migration and recruitment of blood-borne monocyte-derived cells across distinct local gateways. This invasion process drastically increases border complexity and can lead to parenchymal infiltration of blood-borne phagocytes playing a direct role both in damage and in tissue repair. While recent studies and technical advancements have highlighted the extreme heterogeneity of these resident and CNS-invading cells, both the compartment-specific mechanism of invasion and the functional specification of intruding and resident cells remain unclear. This review illustrates the complexity of mononuclear phagocytes at CNS interfaces, indicating how further studies of CNS border dynamics are crucially needed to shed light on local and systemic regulation of CNS functions and dysfunctions.
Collapse
|
204
|
Hsu JL, Lin CH, Chen PL, Lin KJ, Chen TF. Genetic study of young-onset dementia using targeted gene panel sequencing in Taiwan. Am J Med Genet B Neuropsychiatr Genet 2021; 186:67-76. [PMID: 33580635 DOI: 10.1002/ajmg.b.32836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/21/2020] [Accepted: 01/23/2021] [Indexed: 12/12/2022]
Abstract
Recent genetic progress allows the molecular diagnosis of young-onset dementia, including Alzheimer's disease (AD) and frontotemporal dementia (FTD). We aimed to identify the mutational and clinical spectra of causal genes in a Taiwanese cohort of young-onset dementia. Ninety-one patients with young-onset dementia and 22 age/gender-matched controls were recruited. Genetic causes were identified by a targeted panel containing 90 causative genes for AD, FTD, and related neurodegenerative disorders. Plasma biomarkers, including total tau, Aβ42, and Aβ40, were assayed. Molecular amyloid and tau PET scans were performed in some patients carrying mutations. Nine of 52 patients (17.3%) with young-onset AD had mutations: 2 (22.2%), 4 (44.5%), 2 (22.2%), and 1 (11.1%) in APP, PSEN1, PSEN2, and TREM2, respectively. Two of 33 patients (6.1%) with young-onset FTD had mutations in MAPT and LRRK2. Three of the 6 patients (50.0%) with possible FTD combined with other neurodegenerative disorders had individual mutations in APP, PSEN2, or MAPT. Patients with PSEN1 mutations had earlier onset of disease than those without mutations (p = .02). Plasma level of total tau was increased and Aβ42 and Aβ40 levels decreased in all groups of dementia patients compared to controls. Our findings provide a genetic spectrum of young-onset dementia in our population.
Collapse
Affiliation(s)
- Jung-Lung Hsu
- Department of Neurology, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital and Chang Gung University, New Taipei City, Taiwan.,Taipei Medical University, Graduate Institute of Humanities in Medicine and Research Center for Brain and Consciousness, Shuang Ho Hospital, Taipei, Taiwan
| | - Chin-Hsien Lin
- Department of Neurology, Centre of Parkinson and Movement Disorders, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-Lung Chen
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.,Graduate Institute of Medical Genomics and Proteomics, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Kun-Ju Lin
- Department of Nuclear Medicine and Center for Advanced Molecular Imaging and Translation, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.,Healthy Aging Research Center and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ta-Fu Chen
- Department of Neurology, Centre of Parkinson and Movement Disorders, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| |
Collapse
|
205
|
He L, Loika Y, Park Y, Bennett DA, Kellis M, Kulminski AM. Exome-wide age-of-onset analysis reveals exonic variants in ERN1 and SPPL2C associated with Alzheimer's disease. Transl Psychiatry 2021; 11:146. [PMID: 33637690 PMCID: PMC7910483 DOI: 10.1038/s41398-021-01263-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/07/2021] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
Despite recent discoveries in genome-wide association studies (GWAS) of genomic variants associated with Alzheimer's disease (AD), its underlying biological mechanisms are still elusive. The discovery of novel AD-associated genetic variants, particularly in coding regions and from APOE ε4 non-carriers, is critical for understanding the pathology of AD. In this study, we carried out an exome-wide association analysis of age-of-onset of AD with ~20,000 subjects and placed more emphasis on APOE ε4 non-carriers. Using Cox mixed-effects models, we find that age-of-onset shows a stronger genetic signal than AD case-control status, capturing many known variants with stronger significance, and also revealing new variants. We identified two novel variants, rs56201815, a rare synonymous variant in ERN1, and rs12373123, a common missense variant in SPPL2C in the MAPT region in APOE ε4 non-carriers. Besides, a rare missense variant rs144292455 in TACR3 showed the consistent direction of effect sizes across all studies with a suggestive significant level. In an attempt to unravel their regulatory and biological functions, we found that the minor allele of rs56201815 was associated with lower average FDG uptake across five brain regions in ADNI. Our eQTL analyses based on 6198 gene expression samples from ROSMAP and GTEx revealed that the minor allele of rs56201815 was potentially associated with elevated expression of ERN1, a key gene triggering unfolded protein response (UPR), in multiple brain regions, including the posterior cingulate cortex and nucleus accumbens. Our cell-type-specific eQTL analysis using ~80,000 single nuclei in the prefrontal cortex revealed that the protective minor allele of rs12373123 significantly increased the expression of GRN in microglia, and was associated with MAPT expression in astrocytes. These findings provide novel evidence supporting the hypothesis of the potential involvement of the UPR to ER stress in the pathological pathway of AD, and also give more insights into underlying regulatory mechanisms behind the pleiotropic effects of rs12373123 in multiple degenerative diseases including AD and Parkinson's disease.
Collapse
Affiliation(s)
- Liang He
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC, USA.
| | - Yury Loika
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC, USA
| | - Yongjin Park
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge, MA, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Manolis Kellis
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge, MA, USA.
| | - Alexander M Kulminski
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC, USA.
| |
Collapse
|
206
|
Fairley LH, Wong JH, Barron AM. Mitochondrial Regulation of Microglial Immunometabolism in Alzheimer's Disease. Front Immunol 2021; 12:624538. [PMID: 33717134 PMCID: PMC7947196 DOI: 10.3389/fimmu.2021.624538] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/21/2021] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is an age-associated terminal neurodegenerative disease with no effective treatments. Dysfunction of innate immunity is implicated in the pathogenesis of AD, with genetic studies supporting a causative role in the disease. Microglia, the effector cells of innate immunity in the brain, are highly plastic and perform a diverse range of specialist functions in AD, including phagocytosing and removing toxic aggregates of beta amyloid and tau that drive neurodegeneration. These immune functions require high energy demand, which is regulated by mitochondria. Reflecting this, microglia have been shown to be highly metabolically flexible, reprogramming their mitochondrial function upon inflammatory activation to meet their energy demands. However, AD-associated genetic risk factors and pathology impair microglial metabolic programming, and metabolic derailment has been shown to cause innate immune dysfunction in AD. These findings suggest that immunity and metabolic function are intricately linked processes, and targeting microglial metabolism offers a window of opportunity for therapeutic treatment of AD. Here, we review evidence for the role of metabolic programming in inflammatory functions in AD, and discuss mitochondrial-targeted immunotherapeutics for treatment of the disease.
Collapse
Affiliation(s)
- Lauren H Fairley
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Jia Hui Wong
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Anna M Barron
- Neurobiology of Aging and Disease Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| |
Collapse
|
207
|
Abstract
Alzheimer’s disease (AD) is the leading cause of neurodegeneration in the elderly and is clinically characterized by slowly progressing cognitive decline, which most commonly affects episodic memory function. This eventually leads to difficulties in activities of daily living. Biomarker studies show that the underlying pathology of AD begins 20 years before clinical symptoms. This results in the need to define specific targets and preclinical stages in order to address the problems of this disease at an earlier point in time. Genetic studies are indispensable for gaining insight into the etiology of neurodegenerative diseases and can play a major role in the early definition of the individual disease risk. This review provides an overview of the currently known genetic features of AD.
Collapse
Affiliation(s)
- Theresa König
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | | |
Collapse
|
208
|
The Role of Butyrylcholinesterase and Iron in the Regulation of Cholinergic Network and Cognitive Dysfunction in Alzheimer's Disease Pathogenesis. Int J Mol Sci 2021; 22:ijms22042033. [PMID: 33670778 PMCID: PMC7922581 DOI: 10.3390/ijms22042033] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), the most common form of dementia in elderly individuals, is marked by progressive neuron loss. Despite more than 100 years of research on AD, there is still no treatment to cure or prevent the disease. High levels of amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain are neuropathological hallmarks of AD. However, based on postmortem analyses, up to 44% of individuals have been shown to have high Aβ deposits with no clinical signs, due to having a “cognitive reserve”. The biochemical mechanism explaining the prevention of cognitive impairment in the presence of Aβ plaques is still unknown. It seems that in addition to protein aggregation, neuroinflammatory changes associated with aging are present in AD brains that are correlated with a higher level of brain iron and oxidative stress. It has been shown that iron accumulates around amyloid plaques in AD mouse models and postmortem brain tissues of AD patients. Iron is required for essential brain functions, including oxidative metabolism, myelination, and neurotransmitter synthesis. However, an imbalance in brain iron homeostasis caused by aging underlies many neurodegenerative diseases. It has been proposed that high iron levels trigger an avalanche of events that push the progress of the disease, accelerating cognitive decline. Patients with increased amyloid plaques and iron are highly likely to develop dementia. Our observations indicate that the butyrylcholinesterase (BChE) level seems to be iron-dependent, and reports show that BChE produced by reactive astrocytes can make cognitive functions worse by accelerating the decay of acetylcholine in aging brains. Why, even when there is a genetic risk, do symptoms of the disease appear after many years? Here, we discuss the relationship between genetic factors, age-dependent iron tissue accumulation, and inflammation, focusing on AD.
Collapse
|
209
|
McGrowder DA, Miller F, Vaz K, Nwokocha C, Wilson-Clarke C, Anderson-Cross M, Brown J, Anderson-Jackson L, Williams L, Latore L, Thompson R, Alexander-Lindo R. Cerebrospinal Fluid Biomarkers of Alzheimer's Disease: Current Evidence and Future Perspectives. Brain Sci 2021; 11:215. [PMID: 33578866 PMCID: PMC7916561 DOI: 10.3390/brainsci11020215] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease is a progressive, clinically heterogeneous, and particularly complex neurodegenerative disease characterized by a decline in cognition. Over the last two decades, there has been significant growth in the investigation of cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease. This review presents current evidence from many clinical neurochemical studies, with findings that attest to the efficacy of existing core CSF biomarkers such as total tau, phosphorylated tau, and amyloid-β (Aβ42), which diagnose Alzheimer's disease in the early and dementia stages of the disorder. The heterogeneity of the pathophysiology of the late-onset disease warrants the growth of the Alzheimer's disease CSF biomarker toolbox; more biomarkers showing other aspects of the disease mechanism are needed. This review focuses on new biomarkers that track Alzheimer's disease pathology, such as those that assess neuronal injury (VILIP-1 and neurofilament light), neuroinflammation (sTREM2, YKL-40, osteopontin, GFAP, progranulin, and MCP-1), synaptic dysfunction (SNAP-25 and GAP-43), vascular dysregulation (hFABP), as well as CSF α-synuclein levels and TDP-43 pathology. Some of these biomarkers are promising candidates as they are specific and predict future rates of cognitive decline. Findings from the combinations of subclasses of new Alzheimer's disease biomarkers that improve their diagnostic efficacy in detecting associated pathological changes are also presented.
Collapse
Affiliation(s)
- Donovan A. McGrowder
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Fabian Miller
- Department of Physical Education, Faculty of Education, The Mico University College, 1A Marescaux Road, Kingston 5, Jamaica;
- Department of Biotechnology, Faculty of Science and Technology, The University of the West Indies, Kingston 7, Jamaica;
| | - Kurt Vaz
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Chukwuemeka Nwokocha
- Department of Basic Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (C.N.); (C.W.-C.); (R.A.-L.)
| | - Cameil Wilson-Clarke
- Department of Basic Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (C.N.); (C.W.-C.); (R.A.-L.)
| | - Melisa Anderson-Cross
- School of Allied Health and Wellness, College of Health Sciences, University of Technology, Kingston 7, Jamaica;
| | - Jabari Brown
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Lennox Anderson-Jackson
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Lowen Williams
- Department of Biotechnology, Faculty of Science and Technology, The University of the West Indies, Kingston 7, Jamaica;
| | - Lyndon Latore
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Rory Thompson
- Department of Pathology, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (K.V.); (J.B.); (L.A.-J.); (L.L.); (R.T.)
| | - Ruby Alexander-Lindo
- Department of Basic Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, Kingston 7, Jamaica; (C.N.); (C.W.-C.); (R.A.-L.)
| |
Collapse
|
210
|
Gratuze M, Leyns CE, Sauerbeck AD, St-Pierre MK, Xiong M, Kim N, Serrano JR, Tremblay MÈ, Kummer TT, Colonna M, Ulrich JD, Holtzman DM. Impact of TREM2R47H variant on tau pathology-induced gliosis and neurodegeneration. J Clin Invest 2021; 130:4954-4968. [PMID: 32544086 DOI: 10.1172/jci138179] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 06/10/2020] [Indexed: 12/24/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by plaques containing amyloid-β (Aβ) and neurofibrillary tangles composed of aggregated, hyperphosphorylated tau. Beyond tau and Aβ, evidence suggests that microglia play an important role in AD pathogenesis. Rare variants in the microglia-expressed triggering receptor expressed on myeloid cells 2 (TREM2) gene increase AD risk 2- to 4-fold. It is likely that these TREM2 variants increase AD risk by decreasing the response of microglia to Aβ and its local toxicity. However, neocortical Aβ pathology occurs many years before neocortical tau pathology in AD. Thus, it will be important to understand the role of TREM2 in the context of tauopathy. We investigated the impact of the AD-associated TREM2 variant (R47H) on tau-mediated neuropathology in the PS19 mouse model of tauopathy. We assessed PS19 mice expressing human TREM2CV (common variant) or human TREM2R47H. PS19-TREM2R47H mice had significantly attenuated brain atrophy and synapse loss versus PS19-TREM2CV mice. Gene expression analyses and CD68 immunostaining revealed attenuated microglial reactivity in PS19-TREM2R47H versus PS19-TREM2CV mice. There was also a decrease in phagocytosis of postsynaptic elements by microglia expressing TREM2R47H in the PS19 mice and in human AD brains. These findings suggest that impaired TREM2 signaling reduces microglia-mediated neurodegeneration in the setting of tauopathy.
Collapse
Affiliation(s)
- Maud Gratuze
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Cheryl Eg Leyns
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | - Marie-Kim St-Pierre
- Axe Neurosciences, Centre de Recherche, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Québec City, Québec, Canada.,Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Monica Xiong
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nayeon Kim
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Javier Remolina Serrano
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Québec City, Québec, Canada.,Division of Medical Sciences, University of Victoria, Victoria, British Columbia, Canada
| | | | - Marco Colonna
- Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jason D Ulrich
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - David M Holtzman
- Department of Neurology.,Hope Center for Neurological Disorders, and.,Knight Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
211
|
Triviño JJ, von Bernhardi R. The effect of aged microglia on synaptic impairment and its relevance in neurodegenerative diseases. Neurochem Int 2021; 144:104982. [PMID: 33556444 DOI: 10.1016/j.neuint.2021.104982] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 02/07/2023]
Abstract
Microglia serve key functions in the central nervous system (CNS), participating in the establishment and regulation of synapses and the neuronal network, and regulating activity-dependent plastic changes. As the neuroimmune system, they respond to endogenous and exogenous signals to protect the CNS. In aging, one of the main changes is the establishment of inflamm-aging, a mild chronic inflammation that reduces microglial response to stressors. Neuroinflammation depends mainly on the increased activation of microglia. Microglia over-activation may result in a reduced capacity for performing normal functions related to migration, clearance, and the adoption of an anti-inflammatory state, contributing to an increased susceptibility for neurodegeneration. Oxidative stress contributes both to aging and to the progression of neurodegenerative diseases. Increased production of reactive oxygen species (ROS) and neuroinflammation associated with age- and disease-dependent mechanisms affect synaptic activity and neurotransmission, leading to cognitive dysfunction. Astrocytes prevent microglial cell cytotoxicity by mechanisms mediated by transforming growth factor β1 (TGFβ1). However, TGFβ1-Smad3 pathway is impaired in aging, and the age-related impairment of TGFβ signaling can reduce protective activation while facilitating cytotoxic activation of microglia. A critical analysis on the effect of aging microglia on neuronal function is relevant for the understanding of age-related changes on neuronal function. Here, we present evidence in the context of the "microglial dysregulation hypothesis", which leads to the reduction of the protective functions and increased cytotoxicity of microglia, to discuss the mechanisms involved in neurodegenerative changes and Alzheimer's disease.
Collapse
Affiliation(s)
- Juan José Triviño
- Department of Neurology, Pontificia Universidad Católica de Chile School of Medicine, Laboratory of Neuroscience. Marcoleta 391, Santiago, Chile
| | - Rommy von Bernhardi
- Department of Neurology, Pontificia Universidad Católica de Chile School of Medicine, Laboratory of Neuroscience. Marcoleta 391, Santiago, Chile; Faculty of Health Sciences, Universidad San Sebastián, Lota 2465, Santiago, Chile.
| |
Collapse
|
212
|
TREM2 Mediates Microglial Anti-Inflammatory Activations in Alzheimer's Disease: Lessons Learned from Transcriptomics. Cells 2021; 10:cells10020321. [PMID: 33557250 PMCID: PMC7913972 DOI: 10.3390/cells10020321] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 12/20/2022] Open
Abstract
Alzheimer’s disease (AD) is a lethal neurodegenerative disorder primarily affecting the aged population. The etiopathogenesis of AD, especially that of the sporadic type, remains elusive. The triggering receptor expressed on myeloid cells 2 (TREM2), a member of TREM immunoglobulin superfamily, plays a critical role in microglial physiology. Missense mutations in human TREM2 are determined as genetic risk factors associated with the development of sporadic AD. However, the roles of TREM2 in the pathogenesis of AD are still to be established. In this review, we outlined the influence of Trem2 on balance of pro- and anti-inflammatory microglial activations from a perspective of AD mouse model transcriptomics. On this basis, we further speculated the roles of TREM2 in different stages of AD, which may shed light to the development of TREM2-targeted strategy for the prevention and treatment of this neurodegenerative disorder.
Collapse
|
213
|
TREM2, microglia, and Alzheimer's disease. Mech Ageing Dev 2021; 195:111438. [PMID: 33516818 DOI: 10.1016/j.mad.2021.111438] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/02/2021] [Accepted: 01/17/2021] [Indexed: 12/19/2022]
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) has been suggested to play a crucial role in Alzheimer's disease (AD) pathogenesis, as revealed by genome-wide association studies (GWAS). Since then, rapidly increasing literature related to TREM2 has focused on elucidating its role in AD pathology. In this review, we summarize our understanding of TREM2 biology, explore TREM2 functions in microglia, address the multiple mechanisms of TREM2 in AD, and raise key questions for further investigations to elucidate the detailed roles and molecular mechanisms of TREM2 in microglial responses. A major breakthrough in our understanding of TREM2 is based on our hypothesis suggesting that TREM2 may act as a multifaceted player in microglial functions in AD brain homeostasis. We conclude that TREM2 can not only influence microglial functions in amyloid and tau pathologies but also participate in inflammatory responses and metabolism, acting alone or with other molecules, such as apolipoprotein E (APOE). This review provides novel insight into the broad role of TREM2 in microglial function in AD and enables us to develop new strategies aimed at the immune system to treat AD pathogenesis.
Collapse
|
214
|
Ayodele T, Rogaeva E, Kurup JT, Beecham G, Reitz C. Early-Onset Alzheimer's Disease: What Is Missing in Research? Curr Neurol Neurosci Rep 2021; 21:4. [PMID: 33464407 PMCID: PMC7815616 DOI: 10.1007/s11910-020-01090-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Early-onset Alzheimer's disease (EOAD), defined as Alzheimer's disease (AD) occurring before age 65, is significantly less well studied than the late-onset form (LOAD) despite EOAD often presenting with a more aggressive disease progression. The aim of this review is to summarize the current understanding of the etiology of EOAD, their translation into clinical practice, and to suggest steps to be taken to move our understanding forward. RECENT FINDINGS EOAD cases make up 5-10% of AD cases but only 10-15% of these cases show known mutations in the APP, PSEN1, and PSEN2, which are linked to EOAD. New data suggests that these unexplained cases following a non-Mendelian pattern of inheritance is potentially caused by a mix of common and newly discovered rare variants. However, only a fraction of this genetic variation has been identified to date leaving the molecular mechanisms underlying this type of AD and their association with clinical, biomarker, and neuropathological changes unclear. While great advancements have been made in characterizing EOAD, much work is needed to disentangle the molecular mechanisms underlying this type of AD and to identify putative targets for more precise disease screening, diagnosis, prevention, and treatment.
Collapse
Affiliation(s)
- Temitope Ayodele
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, 60 Leonard Avenue, Toronto, ON, M5T 0S8, Canada
| | - Jiji T Kurup
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Gary Beecham
- The John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Christiane Reitz
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
- The Gertrude H. Sergievsky Center, Columbia University, New York, NY, USA.
- Department of Neurology, Columbia University, New York, NY, USA.
- Department of Epidemiology, Sergievsky Center, Taub Institute for Research on the Aging Brain, Columbia University, 630 W 168th Street, New York, NY, 10032, USA.
| |
Collapse
|
215
|
Hu Y, Sun JY, Zhang Y, Zhang H, Gao S, Wang T, Han Z, Wang L, Sun BL, Liu G. rs1990622 variant associates with Alzheimer's disease and regulates TMEM106B expression in human brain tissues. BMC Med 2021; 19:11. [PMID: 33461566 PMCID: PMC7814705 DOI: 10.1186/s12916-020-01883-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/08/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND It has been well established that the TMEM106B gene rs1990622 variant was a frontotemporal dementia (FTD) risk factor. Until recently, growing evidence highlights the role of TMEM106B in Alzheimer's disease (AD). However, it remains largely unclear about the role of rs1990622 variant in AD. METHODS Here, we conducted comprehensive analyses including genetic association study, gene expression analysis, eQTLs analysis, and colocalization analysis. In stage 1, we conducted a genetic association analysis of rs1990622 using large-scale genome-wide association study (GWAS) datasets from International Genomics of Alzheimer's Project (21,982 AD and 41,944 cognitively normal controls) and UK Biobank (314,278 participants). In stage 2, we performed a gene expression analysis of TMEM106B in 49 different human tissues using the gene expression data in GTEx. In stage 3, we performed an expression quantitative trait loci (eQTLs) analysis using multiple datasets from UKBEC, GTEx, and Mayo RNAseq Study. In stage 4, we performed a colocalization analysis to provide evidence of the AD GWAS and eQTLs pair influencing both AD and the TMEM106B expression at a particular region. RESULTS We found (1) rs1990622 variant T allele contributed to AD risk. A sex-specific analysis in UK Biobank further indicated that rs1990622 T allele only contributed to increased AD risk in females, but not in males; (2) TMEM106B showed different expression in different human brain tissues especially high expression in cerebellum; (3) rs1990622 variant could regulate the expression of TMEM106B in human brain tissues, which vary considerably in different disease statuses, the mean ages at death, the percents of females, and the different descents of the selected donors; (4) colocalization analysis provided suggestive evidence that the same variant contributed to AD risk and TMEM106B expression in cerebellum. CONCLUSION Our comprehensive analyses highlighted the role of FTD rs1990622 variant in AD risk. This cross-disease approach may delineate disease-specific and common features, which will be important for both diagnostic and therapeutic development purposes. Meanwhile, these findings highlight the importance to better understand TMEM106B function and dysfunction in the context of normal aging and neurodegenerative diseases.
Collapse
Affiliation(s)
- Yang Hu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, 150080, China
| | - Jing-Yi Sun
- Shandong Provincial Hospital, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250021, China
| | - Yan Zhang
- Department of Pathology, The Affiliated Hospital of Weifang Medical University, Weifang, 261053, China
| | - Haihua Zhang
- Beijing Institute for Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Shan Gao
- Beijing Institute for Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Tao Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
| | - Zhifa Han
- School of Medicine, School of Pharmaceutical Sciences, THU-PKU Center for Life Sciences, Tsinghua University, Beijing, China.,State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China.,Department of Pathophysiology, Peking Union Medical College, Beijing, China
| | - Longcai Wang
- Department of Anesthesiology, The Affiliated Hospital of Weifang Medical University, Weifang, 261053, China
| | - Bao-Liang Sun
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong; Department of Neurology, Second Affiliated Hospital; Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China
| | - Guiyou Liu
- Beijing Institute for Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, 100069, China. .,Chinese Institute for Brain Research, Beijing, China. .,Key Laboratory of Cerebral Microcirculation in Universities of Shandong; Department of Neurology, Second Affiliated Hospital; Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, 271000, Shandong, China. .,National Engineering Laboratory of Internet Medical Diagnosis and Treatment Technology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China. .,Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China.
| |
Collapse
|
216
|
Loeffler DA. Modifiable, Non-Modifiable, and Clinical Factors Associated with Progression of Alzheimer's Disease. J Alzheimers Dis 2021; 80:1-27. [PMID: 33459643 DOI: 10.3233/jad-201182] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
There is an extensive literature relating to factors associated with the development of Alzheimer's disease (AD), but less is known about factors which may contribute to its progression. This review examined the literature with regard to 15 factors which were suggested by PubMed search to be positively associated with the cognitive and/or neuropathological progression of AD. The factors were grouped as potentially modifiable (vascular risk factors, comorbidities, malnutrition, educational level, inflammation, and oxidative stress), non-modifiable (age at clinical onset, family history of dementia, gender, Apolipoprotein E ɛ4, genetic variants, and altered gene regulation), and clinical (baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs). Although conflicting results were found for the majority of factors, a positive association was found in nearly all studies which investigated the relationship of six factors to AD progression: malnutrition, genetic variants, altered gene regulation, baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs. Whether these or other factors which have been suggested to be associated with AD progression actually influence the rate of decline of AD patients is unclear. Therapeutic approaches which include addressing of modifiable factors associated with AD progression should be considered.
Collapse
Affiliation(s)
- David A Loeffler
- Beaumont Research Institute, Department of Neurology, Beaumont Health, Royal Oak, MI, USA
| |
Collapse
|
217
|
Zheng Q, Li G, Wang S, Zhou Y, Liu K, Gao Y, Zhou Y, Zheng L, Zhu L, Deng Q, Wu M, Di A, Zhang L, Zhao Y, Zhang H, Sun H, Dong C, Xu H, Wang X. Trisomy 21-induced dysregulation of microglial homeostasis in Alzheimer's brains is mediated by USP25. SCIENCE ADVANCES 2021; 7:7/1/eabe1340. [PMID: 33523861 PMCID: PMC7775784 DOI: 10.1126/sciadv.abe1340] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 11/05/2020] [Indexed: 05/11/2023]
Abstract
Down syndrome (DS), caused by trisomy of chromosome 21, is the most significant risk factor for early-onset Alzheimer's disease (AD); however, underlying mechanisms linking DS and AD remain unclear. Here, we show that triplication of homologous chromosome 21 genes aggravates neuroinflammation in combined murine DS-AD models. Overexpression of USP25, a deubiquitinating enzyme encoded by chromosome 21, results in microglial activation and induces synaptic and cognitive deficits, whereas genetic ablation of Usp25 reduces neuroinflammation and rescues synaptic and cognitive function in 5×FAD mice. Mechanistically, USP25 deficiency attenuates microglia-mediated proinflammatory cytokine overproduction and synapse elimination. Inhibition of USP25 reestablishes homeostatic microglial signatures and restores synaptic and cognitive function in 5×FAD mice. In summary, we demonstrate an unprecedented role for trisomy 21 and pathogenic effects associated with microgliosis as a result of the increased USP25 dosage, implicating USP25 as a therapeutic target for neuroinflammation in DS and AD.
Collapse
Affiliation(s)
- Qiuyang Zheng
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Guilin Li
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Shihua Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
- School of Medicine, Xizang Minzu University, Xianyang, Shaanxi 712082, China
| | - Ying Zhou
- Department of Translational Medicine, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Ke Liu
- Department of Translational Medicine, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Yue Gao
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Yulin Zhou
- Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, Fujian 361003, China
| | - Liangkai Zheng
- Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, Fujian 361003, China
| | - Lin Zhu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Qingfang Deng
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Meiling Wu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Anjie Di
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Lishan Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Yingjun Zhao
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Hongfeng Zhang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Hao Sun
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
| | - Chen Dong
- Institute for Immunology, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Huaxi Xu
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China
- Center for Brain Sciences, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian 361003, China
| | - Xin Wang
- State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian 361005, China.
| |
Collapse
|
218
|
Zetterberg H, Bendlin BB. Biomarkers for Alzheimer's disease-preparing for a new era of disease-modifying therapies. Mol Psychiatry 2021; 26:296-308. [PMID: 32251378 PMCID: PMC8172244 DOI: 10.1038/s41380-020-0721-9] [Citation(s) in RCA: 190] [Impact Index Per Article: 63.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/25/2022]
Abstract
Clinical trial results presented in 2019 suggest that antibody-based removal of cerebral amyloid β (Aβ) plaques may possibly clear tau tangles and modestly slow cognitive decline in symptomatic Alzheimer's disease (AD). Although regulatory approval of this approach is still pending, preparing the healthcare system for the advent of disease-modifying therapies against AD is imperative. In particular, it will be necessary to identify the most suitable biomarkers to facilitate appropriate treatment of AD. Here, we give an update on recent developments in fluid and imaging biomarkers for AD-related pathologies and discuss potential approaches that could be adopted to screen for and clarify the underlying pathology in people seeking medical advice because of cognitive symptoms. We succinctly review recent data regarding biomarkers for Aβ and tau pathology, neurodegeneration, synaptic dysfunction, and inflammation, highlight the need for further research into common copathologies, and suggest how different biomarkers could be used (most likely in combination) to facilitate the development and clinical implementation of novel drug candidates against AD.
Collapse
Affiliation(s)
- Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK.
- UK Dementia Research Institute at UCL, London, UK.
| | - Barbara B Bendlin
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
219
|
Lana D, Ugolini F, Giovannini MG. Space-Dependent Glia-Neuron Interplay in the Hippocampus of Transgenic Models of β-Amyloid Deposition. Int J Mol Sci 2020; 21:E9441. [PMID: 33322419 PMCID: PMC7763751 DOI: 10.3390/ijms21249441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
This review is focused on the description and discussion of the alterations of astrocytes and microglia interplay in models of Alzheimer's disease (AD). AD is an age-related neurodegenerative pathology with a slowly progressive and irreversible decline of cognitive functions. One of AD's histopathological hallmarks is the deposition of amyloid beta (Aβ) plaques in the brain. Long regarded as a non-specific, mere consequence of AD pathology, activation of microglia and astrocytes is now considered a key factor in both initiation and progression of the disease, and suppression of astrogliosis exacerbates neuropathology. Reactive astrocytes and microglia overexpress many cytokines, chemokines, and signaling molecules that activate or damage neighboring cells and their mutual interplay can result in virtuous/vicious cycles which differ in different brain regions. Heterogeneity of glia, either between or within a particular brain region, is likely to be relevant in healthy conditions and disease processes. Differential crosstalk between astrocytes and microglia in CA1 and CA3 areas of the hippocampus can be responsible for the differential sensitivity of the two areas to insults. Understanding the spatial differences and roles of glia will allow us to assess how these interactions can influence the state and progression of the disease, and will be critical for identifying therapeutic strategies.
Collapse
Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| |
Collapse
|
220
|
Edwin TH, Henjum K, Nilsson LN, Watne LO, Persson K, Eldholm RS, Saltvedt I, Halaas NB, Selbæk G, Engedal K, Strand BH, Knapskog A. A high cerebrospinal fluid soluble TREM2 level is associated with slow clinical progression of Alzheimer's disease. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2020; 12:e12128. [PMID: 33313376 PMCID: PMC7720866 DOI: 10.1002/dad2.12128] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 12/19/2022]
Abstract
INTRODUCTION The progression rate of Alzheimer's disease (AD) varies and might be affected by the triggering receptor expressed on myeloid cells (TREM2) activity. We explored if cerebrospinal fluid (CSF) soluble TREM2 (sTREM2), a proxy of microglial activity, is associated with clinical progression rate. METHODS Patients with clinical AD (N = 231) were followed for up to 3 years after diagnosis. Cognitively healthy controls (N = 42) were followed for 5 years. CSF sTREM2 was analyzed by enzyme-linked immunosorbent assay. Group-based trajectory modeling revealed distinct clinical progression groups. RESULTS Higher CSF sTREM2 was associated with slow clinical progression. The slow- and medium-progressing groups had higher CSF sTREM2 than the cognitively healthy, who had a similar level to patients with rapid clinical progression. DISCUSSION CSF sTREM2 levels were associated with clinical progression in AD, regardless of core biomarkers. This could be useful in assessing disease development in relation to patient care and clinical trial recruitment.
Collapse
Affiliation(s)
- Trine Holt Edwin
- Department of Dementia ResearchNorwegian National Advisory Unit on Ageing and HealthVestfold Hospital TrustTønsbergNorway
- Department of Geriatric MedicineOslo University HospitalOsloNorway
- Institute of Clinical Medicine and Institute of Health and SocietyFaculty of MedicineUniversity of OsloOsloNorway
| | - Kristi Henjum
- Department of Geriatric MedicineOslo University HospitalOsloNorway
- Department of PharmacologyUniversity of Oslo and Oslo University HospitalOsloNorway
- Department of Geriatric MedicineOslo Delirium Research GroupOslo University HospitalOsloNorway
| | - Lars N.G. Nilsson
- Department of PharmacologyUniversity of Oslo and Oslo University HospitalOsloNorway
| | - Leiv Otto Watne
- Department of Geriatric MedicineOslo University HospitalOsloNorway
- Department of Geriatric MedicineOslo Delirium Research GroupOslo University HospitalOsloNorway
| | - Karin Persson
- Department of Dementia ResearchNorwegian National Advisory Unit on Ageing and HealthVestfold Hospital TrustTønsbergNorway
- Department of Geriatric MedicineOslo University HospitalOsloNorway
| | - Rannveig Sakshaug Eldholm
- Department of Neuromedicine and Movement ScienceNorwegian University of Science and TechnologyTrondheimNorway
- Department of GeriatricsSt. Olavs HospitalUniversity Hospital of TrondheimTrondheimNorway
| | - Ingvild Saltvedt
- Department of Neuromedicine and Movement ScienceNorwegian University of Science and TechnologyTrondheimNorway
- Department of GeriatricsSt. Olavs HospitalUniversity Hospital of TrondheimTrondheimNorway
| | - Nathalie Bodd Halaas
- Institute of Clinical Medicine and Institute of Health and SocietyFaculty of MedicineUniversity of OsloOsloNorway
- Department of Geriatric MedicineOslo Delirium Research GroupOslo University HospitalOsloNorway
- Department of PsychologyCenter for Lifespan Changes in Brain and CognitionUniversity of OsloOsloNorway
| | - Geir Selbæk
- Department of Dementia ResearchNorwegian National Advisory Unit on Ageing and HealthVestfold Hospital TrustTønsbergNorway
- Department of Geriatric MedicineOslo University HospitalOsloNorway
- Institute of Clinical Medicine and Institute of Health and SocietyFaculty of MedicineUniversity of OsloOsloNorway
| | - Knut Engedal
- Department of Dementia ResearchNorwegian National Advisory Unit on Ageing and HealthVestfold Hospital TrustTønsbergNorway
- Department of Geriatric MedicineOslo University HospitalOsloNorway
| | - Bjørn Heine Strand
- Department of Dementia ResearchNorwegian National Advisory Unit on Ageing and HealthVestfold Hospital TrustTønsbergNorway
- Institute of Clinical Medicine and Institute of Health and SocietyFaculty of MedicineUniversity of OsloOsloNorway
- Department of Chronic Diseases and AgeingNorwegian Institute of Public HealthOsloNorway
| | | |
Collapse
|
221
|
Wong E, Frost GR, Li YM. γ-Secretase Modulatory Proteins: The Guiding Hand Behind the Running Scissors. Front Aging Neurosci 2020; 12:614690. [PMID: 33343338 PMCID: PMC7738330 DOI: 10.3389/fnagi.2020.614690] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
Described as the "proteasome of the membrane" or the "scissors in the membrane," γ-secretase has notoriously complicated biology, and even after decades of research, the full extent of its regulatory mechanism remains unclear. γ-Secretase is an intramembrane aspartyl protease complex composed of four obligatory subunits: Nicastrin (NCT), Presenilin (PS), Presenilin Enhancer-2 (Pen-2), and Anterior pharynx-defective-1 (Aph-1). γ-Secretase cleaves numerous type 1 transmembrane substrates, with no apparent homology, and plays major roles in broad biological pathways such as development, neurogenesis, and cancer. Notch and the amyloid precursor protein (APP) and are undoubtedly the best-studied γ-secretase substrates because of their role in cancer and Alzheimer's disease (AD) and therefore became the focus of increasing studies as an attractive therapeutic target. The regulation of γ-secretase is intricate and involves the function of multiple cellular entities. Recently, γ-secretase modulatory proteins (GSMPs), which are non-essential subunits and yet modulate γ-secretase activity and specificity, have emerged as an important component in guiding γ-secretase. GSMPs are responsive to cellular and environmental changes and therefore, provide another layer of regulation of γ-secretase. This type of enzymatic regulation allows for a rapid and fine-tuning of γ-secretase activity when appropriate signals appear enabling a temporal level of regulation. In this review article, we discuss the latest developments on GSMPs and implications on the development of effective therapeutics for γ-secretase-associated diseases such as AD and cancer.
Collapse
Affiliation(s)
- Eitan Wong
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States
| |
Collapse
|
222
|
Konishi H, Kiyama H. Non-pathological roles of microglial TREM2/DAP12: TREM2/DAP12 regulates the physiological functions of microglia from development to aging. Neurochem Int 2020; 141:104878. [DOI: 10.1016/j.neuint.2020.104878] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 01/01/2023]
|
223
|
Silva MC, Haggarty SJ. Tauopathies: Deciphering Disease Mechanisms to Develop Effective Therapies. Int J Mol Sci 2020; 21:ijms21238948. [PMID: 33255694 PMCID: PMC7728099 DOI: 10.3390/ijms21238948] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 12/13/2022] Open
Abstract
Tauopathies are neurodegenerative diseases characterized by the pathological accumulation of microtubule-associated protein tau (MAPT) in the form of neurofibrillary tangles and paired helical filaments in neurons and glia, leading to brain cell death. These diseases include frontotemporal dementia (FTD) and Alzheimer's disease (AD) and can be sporadic or inherited when caused by mutations in the MAPT gene. Despite an incredibly high socio-economic burden worldwide, there are still no effective disease-modifying therapies, and few tau-focused experimental drugs have reached clinical trials. One major hindrance for therapeutic development is the knowledge gap in molecular mechanisms of tau-mediated neuronal toxicity and death. For the promise of precision medicine for brain disorders to be fulfilled, it is necessary to integrate known genetic causes of disease, i.e., MAPT mutations, with an understanding of the dysregulated molecular pathways that constitute potential therapeutic targets. Here, the growing understanding of known and proposed mechanisms of disease etiology will be reviewed, together with promising experimental tau-directed therapeutics, such as recently developed tau degraders. Current challenges faced by the fields of tau research and drug discovery will also be addressed.
Collapse
|
224
|
Manich G, Gómez-López AR, Almolda B, Villacampa N, Recasens M, Shrivastava K, González B, Castellano B. Differential Roles of TREM2+ Microglia in Anterograde and Retrograde Axonal Injury Models. Front Cell Neurosci 2020; 14:567404. [PMID: 33328887 PMCID: PMC7715005 DOI: 10.3389/fncel.2020.567404] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/14/2020] [Indexed: 11/13/2022] Open
Abstract
Microglia are the main immune cells of the central nervous system (CNS), and they are devoted to the active surveillance of the CNS during homeostasis and disease. In the last years, the microglial receptor Triggering Receptor Expressed on Myeloid cells-2 (TREM2) has been defined to mediate several microglial functions, including phagocytosis, survival, proliferation, and migration, and to be a key regulator of a new common microglial signature induced under neurodegenerative conditions and aging, also known as disease-associated microglia (DAM). Although microglial TREM2 has been mainly studied in chronic neurodegenerative diseases, few studies address its regulation and functions in acute inflammatory injuries. In this context, the present work aims to study the regulation of TREM2 and its functions after reparative axonal injuries, using two-well established animal models of anterograde and retrograde neuronal degeneration: the perforant pathway transection (PPT) and the facial nerve axotomy (FNA). Our results indicate the appearance of a subpopulation of microglia expressing TREM2 after both anterograde and retrograde axonal injury. TREM2+ microglia were not directly related to proliferation, instead, they were associated with specific recognition and/or phagocytosis of myelin and degenerating neurons, as assessed by immunohistochemistry and flow cytometry. Characterization of TREM2+ microglia showed expression of CD16/32, CD68, and occasional Galectin-3. However, specific singularities within each model were observed in P2RY12 expression, which was only downregulated after PPT, and in ApoE, where de novo expression was detected only in TREM2+ microglia after FNA. Finally, we report that the pro-inflammatory or anti-inflammatory cytokine microenvironment, which may affect phagocytosis, did not directly modify the induction of TREM2+ subpopulation in any injury model, although it changed TREM2 levels due to modification of the microglial activation pattern. In conclusion, we describe a unique TREM2+ microglial subpopulation induced after axonal injury, which is directly associated with phagocytosis of specific cell remnants and show different phenotypes, depending on the microglial activation status and the degree of tissue injury.
Collapse
Affiliation(s)
- Gemma Manich
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Ariadna Regina Gómez-López
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Beatriz Almolda
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Nàdia Villacampa
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Mireia Recasens
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Kalpana Shrivastava
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Berta González
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| | - Bernardo Castellano
- Department of Cell Biology, Physiology, and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Barcelona, Spain
| |
Collapse
|
225
|
Pardridge WM. Treatment of Alzheimer's Disease and Blood-Brain Barrier Drug Delivery. Pharmaceuticals (Basel) 2020; 13:E394. [PMID: 33207605 PMCID: PMC7697739 DOI: 10.3390/ph13110394] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Despite the enormity of the societal and health burdens caused by Alzheimer's disease (AD), there have been no FDA approvals for new therapeutics for AD since 2003. This profound lack of progress in treatment of AD is due to dual problems, both related to the blood-brain barrier (BBB). First, 98% of small molecule drugs do not cross the BBB, and ~100% of biologic drugs do not cross the BBB, so BBB drug delivery technology is needed in AD drug development. Second, the pharmaceutical industry has not developed BBB drug delivery technology, which would enable industry to invent new therapeutics for AD that actually penetrate into brain parenchyma from blood. In 2020, less than 1% of all AD drug development projects use a BBB drug delivery technology. The pathogenesis of AD involves chronic neuro-inflammation, the progressive deposition of insoluble amyloid-beta or tau aggregates, and neural degeneration. New drugs that both attack these multiple sites in AD, and that have been coupled with BBB drug delivery technology, can lead to new and effective treatments of this serious disorder.
Collapse
Affiliation(s)
- William M Pardridge
- Department of Medicine, University of California, Los Angeles, CA 90024, USA
| |
Collapse
|
226
|
Yao AY, Yan R. Activity of Alzheimer's γ-secretase is linked to changes of interferon-induced transmembrane proteins (IFITM) in innate immunity. Mol Neurodegener 2020; 15:69. [PMID: 33183335 PMCID: PMC7661164 DOI: 10.1186/s13024-020-00417-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 10/30/2020] [Indexed: 02/08/2023] Open
Abstract
The activity of γ-secretase is critical to the pathogenesis of Alzheimer's disease (AD). How its activity is regulated is intriguing and highly important for any AD therapy that focuses on reduction of toxic amyloid peptides and amyloid deposition in patients. Recently, interferon-induced transmembrane protein 3 (IFITM3) has been identified as a novel regulator of γ-secretase through a specific interaction. This commentary highlights this exciting study and provides an updated link of γ-secretase activity to innate immunity through IFITM3.
Collapse
Affiliation(s)
- Annie Y. Yao
- Department of Neuroscience, University of Connecticut Health, Farmington, CT USA
| | - Riqiang Yan
- Department of Neuroscience, University of Connecticut Health, Farmington, CT USA
| |
Collapse
|
227
|
What are activated and reactive glia and what is their role in neurodegeneration? Neurobiol Dis 2020; 148:105172. [PMID: 33171230 DOI: 10.1016/j.nbd.2020.105172] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/11/2020] [Accepted: 11/05/2020] [Indexed: 12/11/2022] Open
Abstract
In injury and disease, microglia and astrocytes - two major non-neuronal cell types in the central nervous system (CNS) - undergo morphological, transcriptional, and functional changes, which can underlie pathogenesis and dysfunction of the CNS. Microglia, the brain's tissue resident parenchymal macrophages, are described as becoming "activated" as they deftly change their production of different inflammatory mediators, alter the surveillance behavior of their cellular protrusions, and differentially influence the function of astrocytes. For their part, astrocytes - the most abundant glial cell type - are said to become "reactive", which implies (perhaps inappropriately) causality for the changes astrocytes undergo. Reactive astrocytes variably undergo process hypertrophy, decrease their normal homeostatic functions such as facilitating synapse formation, and in some cases act to form a tissue scar in response to insult. But what do these terms "activation" and "reactivity" mean, anyway? And how do these changed microglia and astrocytes contribute to neurodegenerative disease (ND)? Here, we describe our current understanding of the role of activated and reactive microglia and astrocytes in ND, as well as our current understanding about what these states are and might mean. We survey the earliest description of these cells by histopathologists, their transcriptomic identities, and finally our mechanistic understanding of their functions in ND.
Collapse
|
228
|
Quarta A, Berneman Z, Ponsaerts P. Functional consequences of a close encounter between microglia and brain-infiltrating monocytes during CNS pathology and repair. J Leukoc Biol 2020; 110:89-106. [PMID: 33155726 DOI: 10.1002/jlb.3ru0820-536r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
Neuroinflammation is recognized as an important factor contributing to the development and progression of several central nervous system (CNS) disorders. Upon CNS trauma or disease, parenchymal microglia highly proliferate and accumulate in and around the lesion site. In addition, blood-derived monocytes can infiltrate the inflamed CNS in response to cellular damage and/or a compromised blood-brain barrier. Both microglia and infiltrating monocytes are characterized by multiple functional states and can either display highly proinflammatory properties or promote resolution of inflammation and tissue regeneration. Despite sharing some basic immunologic functions, microglia and monocytes display many distinctive features, which ultimately define their contribution to neuropathology. Understanding how the innate immune system participates to brain disease is imperative to identify novel treatment options for CNS inflammatory disorders. In this context, existing and newly developed in vitro platforms for disease modeling are fundamental tools to investigate and modulate microglia and monocyte immune functions within a specific neuropathologic context. In this review, we first briefly summarize the current knowledge on microglia and monocyte ontogenesis, as well as their complex and interconnected contributions to the development of various CNS pathologies. Following the well-recognized concept that both microglia and monocytes can either exert neuroprotective functions or exacerbate tissue damage, we provide a comprehensive overview of cellular models currently available for in vitro study of neuroinflammatory responses. In this context, we highlight how simplified single-cell models may not always correctly recapitulate in vivo biology, hence future research should move toward novel models with higher and multicellular complexity.
Collapse
Affiliation(s)
- Alessandra Quarta
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Zwi Berneman
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| |
Collapse
|
229
|
Li Z, Shue F, Zhao N, Shinohara M, Bu G. APOE2: protective mechanism and therapeutic implications for Alzheimer's disease. Mol Neurodegener 2020; 15:63. [PMID: 33148290 PMCID: PMC7640652 DOI: 10.1186/s13024-020-00413-4] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 10/17/2020] [Indexed: 02/06/2023] Open
Abstract
Investigations of apolipoprotein E (APOE) gene, the major genetic risk modifier for Alzheimer's disease (AD), have yielded significant insights into the pathogenic mechanism. Among the three common coding variants, APOE*ε4 increases, whereas APOE*ε2 decreases the risk of late-onset AD compared with APOE*ε3. Despite increased understanding of the detrimental effect of APOE*ε4, it remains unclear how APOE*ε2 confers protection against AD. Accumulating evidence suggests that APOE*ε2 protects against AD through both amyloid-β (Aβ)-dependent and independent mechanisms. In addition, APOE*ε2 has been identified as a longevity gene, suggesting a systemic effect of APOE*ε2 on the aging process. However, APOE*ε2 is not entirely benign; APOE*ε2 carriers exhibit increased risk of certain cerebrovascular diseases and neurological disorders. Here, we review evidence from both human and animal studies demonstrating the protective effect of APOE*ε2 against AD and propose a working model depicting potential underlying mechanisms. Finally, we discuss potential therapeutic strategies designed to leverage the protective effect of APOE2 to treat AD.
Collapse
Affiliation(s)
- Zonghua Li
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Neuroscience Graduate Program, Mayo Clinic, Jacksonville, FL, USA
| | - Na Zhao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Mitsuru Shinohara
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, 7-430 Morioka, Obu, Aichi, 474-8511, Japan.
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Neuroscience Graduate Program, Mayo Clinic, Jacksonville, FL, USA.
| |
Collapse
|
230
|
Loss of TREM2 Confers Resilience to Synaptic and Cognitive Impairment in Aged Mice. J Neurosci 2020; 40:9552-9563. [PMID: 33139402 DOI: 10.1523/jneurosci.2193-20.2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/12/2020] [Accepted: 10/27/2020] [Indexed: 11/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor exclusively expressed by microglia in the brain, modulates microglial immune homeostasis. Human genetic studies have shown that the loss-of-function mutations in TREM2 signaling are strongly associated with an elevated risk of age-related neurodegenerative diseases including Alzheimer's disease (AD). Numerous studies have investigated the impact of TREM2 deficiency in the pathogenic process of AD. However, the role of TREM2 in shaping neuronal and cognitive function during normal aging is underexplored. In the present study, we employed behavioral, electrophysiological, and biochemical approaches to assess cognitive and synaptic function in male and female young and aged TREM2-deficient (Trem2-/-) mice compared with age-matched, sex-matched, and genetic background-matched wild-type (WT) C57BL/6J controls. Young Trem2-/- mice exhibited normal cognitive function and synaptic plasticity but had increased dendritic spine density compared with young WT. Unexpectedly, aged Trem2-/- mice showed superior cognitive performance compared with aged WT controls. Consistent with the behavioral data, aged Trem2-/- mice displayed significantly enhanced hippocampal long-term potentiation (LTP) and increased dendritic spine density and synaptic markers compared with aged WT mice. Taken together, these findings suggest that loss of TREM2 affects the neuronal structure and confers resilience to age-related synaptic and cognitive impairment during non-pathogenic aging.SIGNIFICANCE STATEMENT Microglia are innate immune cells of the brain that orchestrates neurodevelopment, synaptic function, and immune response to environmental stimuli. Microglial triggering receptor expressed on myeloid cells 2 (TREM2) signaling plays pivotal roles in regulating these functions and loss of TREM2 signaling leads to increased risk of developing age-related neurologic disorders. However, the neurologic role of TREM2 in normal aging is poorly understood. The results of the present study unveil the positive impacts of TREM2 deficiency on cognitive and synaptic function during aging and suggest that TREM2 may exert detrimental effects on neuronal function. The possibility of age-related negative impacts from TREM2 is critically important since TREM2 has emerged as a major therapeutic target for Alzheimer's dementia.
Collapse
|
231
|
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]
|
232
|
Holloway OG, King AE, Ziebell JM. Microglia Demonstrate Local Mixed Inflammation and a Defined Morphological Shift in an APP/PS1 Mouse Model. J Alzheimers Dis 2020; 77:1765-1781. [DOI: 10.3233/jad-200098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Background: Microglia are traditionally described as the immune cells of the brain and have an inflammatory role in Alzheimer’s disease (AD). Microglial morphological and phenotypic shifts in AD have not been fully characterized; however, microglia are often described as either pro- or anti-inflammatory. Objective: To determine microglial if microglial morphology and phenotype changes with disease status. Methods: This study observed morphology through Iba1 immunohistochemistry on tissue sections encompassing the primary motor cortex and somatosensory barrel fields. Immunohistochemistry for pro-inflammatory markers: CD14 and CD40; and anti-inflammatory markers: CD16 and TREM2, was performed at 3, 6, and 12 months of age which correlated with pre-plaque, onset, and significant plaque load in APP/PS1 brains (n = 6) and compared to age-matched littermate controls (n = 6). Results: Microglia demonstrated a defined morphological shift with time. Deramified morphologies increased in the APP/PS1, at both 6 months (p < 0.0001) and 12 months (p < 0.0001). At 12 months, there were significantly lower numbers of ramified microglia (p < 0.001). Results indicated that microglia have a heterogenic marker immunoreactivity as CD16, TREM2, and CD40 were associated with an activated morphology at the same time points. All inflammatory markers were significantly upregulated at 12 months in the APP/PS1 mice (TREM2 (F (2,30) = 10.75, p = 0.0003), CD40 (F (2,30) = 15.86, p < 0.0001), CD14 (F (2,30) = 6.84, p = 0.0036), and CD16 (F (2,30) = 3.026, p = 0.0635)). Conclusion: Our data indicate that pro- and anti-inflammatory factors of microglia occur in APP/PS1 mice.
Collapse
Affiliation(s)
- Olivia G. Holloway
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| | - Anna E. King
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| | - Jenna M. Ziebell
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| |
Collapse
|
233
|
Kober DL, Stuchell-Brereton MD, Kluender CE, Dean HB, Strickland MR, Steinberg DF, Nelson SS, Baban B, Holtzman DM, Frieden C, Alexander-Brett J, Roberson ED, Song Y, Brett TJ. Functional insights from biophysical study of TREM2 interactions with apoE and Aβ 1-42. Alzheimers Dement 2020; 17:10.1002/alz.12194. [PMID: 33090700 PMCID: PMC8026773 DOI: 10.1002/alz.12194] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Triggering receptor expressed on myeloid cells-2 (TREM2) is an immune receptor expressed on microglia that also can become soluble (sTREM2). How TREM2 engages different ligands remains poorly understood. METHODS We used comprehensive biolayer interferometry (BLI) analysis to investigate TREM2 and sTREM2 interactions with apolipoprotein E (apoE) and monomeric amyloid beta (Aβ) (mAβ42). RESULTS TREM2 engagement of apoE was protein mediated with little effect of lipidation, showing slight affinity differences between isoforms (E4 > E3 > E2). Another family member, TREML2, did not bind apoE. Disease-linked TREM2 variants within a "basic patch" minimally impact apoE binding. Instead, TREM2 uses a unique hydrophobic surface to bind apoE, which requires the apoE hinge region. TREM2 and sTREM2 directly bind mAβ42 and potently inhibit Aβ42 polymerization, suggesting a potential role for soluble sTREM2 in preventing AD pathogenesis. DISCUSSION These findings demonstrate that TREM2 has at least two ligand-binding surfaces that might be therapeutic targets and uncovers a potential function for sTREM2 in directly inhibiting Aβ polymerization.
Collapse
Affiliation(s)
- Daniel L. Kober
- Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, St. Louis, Missouri 63110
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Melissa D. Stuchell-Brereton
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Colin E. Kluender
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
- Biochemistry, Biophysics, and Structural Biology Program, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Hunter B. Dean
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer’s Disease Center, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, AL 35294
- Department of Biomedical Engineering, University of Alabama at Birmingham, AL 35294
| | - Michael R. Strickland
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Deborah F. Steinberg
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Samantha S. Nelson
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Berevan Baban
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - David M. Holtzman
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110
- Charles F. and Joanne Knight Alzheimer’s Disease Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Carl Frieden
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jennifer Alexander-Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Erik D. Roberson
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer’s Disease Center, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, AL 35294
| | - Yuhua Song
- Department of Biomedical Engineering, University of Alabama at Birmingham, AL 35294
| | - Tom J. Brett
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110
| |
Collapse
|
234
|
Franzmeier N, Suárez-Calvet M, Frontzkowski L, Moore A, Hohman TJ, Morenas-Rodriguez E, Nuscher B, Shaw L, Trojanowski JQ, Dichgans M, Kleinberger G, Haass C, Ewers M. Higher CSF sTREM2 attenuates ApoE4-related risk for cognitive decline and neurodegeneration. Mol Neurodegener 2020; 15:57. [PMID: 33032659 PMCID: PMC7545547 DOI: 10.1186/s13024-020-00407-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/24/2020] [Indexed: 12/24/2022] Open
Abstract
Background The Apolipoprotein E ε4 allele (i.e. ApoE4) is the strongest genetic risk factor for sporadic Alzheimer’s disease (AD). TREM2 (i.e. Triggering receptor expressed on myeloid cells 2) is a microglial transmembrane protein brain that plays a central role in microglia activation in response to AD brain pathologies. Whether higher TREM2-related microglia activity modulates the risk to develop clinical AD is an open question. Thus, the aim of the current study was to assess whether higher sTREM2 attenuates the effects of ApoE4-effects on future cognitive decline and neurodegeneration. Methods We included 708 subjects ranging from cognitively normal (CN, n = 221) to mild cognitive impairment (MCI, n = 414) and AD dementia (n = 73) from the Alzheimer’s disease Neuroimaging Initiative. We used linear regression to test the interaction between ApoE4-carriage by CSF-assessed sTREM2 levels as a predictor of longitudinally assessed cognitive decline and MRI-assessed changes in hippocampal volume changes (mean follow-up of 4 years, range of 1.7-7 years). Results Across the entire sample, we found that higher CSF sTREM2 at baseline was associated with attenuated effects of ApoE4-carriage (i.e. sTREM2 x ApoE4 interaction) on longitudinal global cognitive (p = 0.001, Cohen’s f2 = 0.137) and memory decline (p = 0.006, Cohen’s f2 = 0.104) as well as longitudinally assessed hippocampal atrophy (p = 0.046, Cohen’s f2 = 0.089), independent of CSF markers of primary AD pathology (i.e. Aβ1–42, p-tau181). While overall effects of sTREM2 were small, exploratory subanalyses stratified by diagnostic groups showed that beneficial effects of sTREM2 were pronounced in the MCI group. Conclusion Our results suggest that a higher CSF sTREM2 levels are associated with attenuated ApoE4-related risk for future cognitive decline and AD-typical neurodegeneration. These findings provide further evidence that TREM2 may be protective against the development of AD.
Collapse
Affiliation(s)
- Nicolai Franzmeier
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University (LMU), Munich, Germany.
| | - M Suárez-Calvet
- Barcelonaβeta Brain Research Center (BBRC), Pasqual Maragall Foundation, Barcelona, Spain.,IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain.,Servei de Neurologia, Hospital del Mar, Barcelona, Spain
| | - Lukas Frontzkowski
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University (LMU), Munich, Germany
| | - Annah Moore
- Vanderbilt Memory & Alzheimer's Center, Vanderbilt University Medical Center, Nashville, USA
| | - Timothy J Hohman
- Vanderbilt Memory & Alzheimer's Center, Vanderbilt University Medical Center, Nashville, USA
| | - Estrella Morenas-Rodriguez
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Brigitte Nuscher
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Leslie Shaw
- Center for Neurodegenerative Disease Research, Institute on Aging, Perelman School of Medicine University, Philadelphia, USA
| | - John Q Trojanowski
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Martin Dichgans
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University (LMU), Munich, Germany.,Munich Cluster for Systems Neurology, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | | | - Christian Haass
- Chair of Metabolic Biochemistry, Biomedical Center (BMC), Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Michael Ewers
- Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig Maximilian University (LMU), Munich, Germany. .,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
| | | |
Collapse
|
235
|
Smart treatment strategies for alleviating tauopathy and neuroinflammation to improve clinical outcome in Alzheimer's disease. Drug Discov Today 2020; 25:2110-2129. [PMID: 33011341 DOI: 10.1016/j.drudis.2020.09.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/04/2020] [Accepted: 09/23/2020] [Indexed: 01/04/2023]
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disease leading to progressive loss of memory that mainly affects people above 60 years of age. It is one of the leading causes of deaths in the USA. Given its inherent heterogeneity and a still-incomplete understanding of its pathology, biomarkers, and targets available for therapy, it is a challenge to design an effective therapeutic strategy. Several hypotheses have been proposed to understand the disease and to identify reliable markers and targets for treatments. However, none have resulted in strong support from clinical trials. In this review, we objectively discuss the various therapeutic strategies and mechanistic approaches to improve the current clinical outcome of AD therapy.
Collapse
|
236
|
Plotkin SS, Cashman NR. Passive immunotherapies targeting Aβ and tau in Alzheimer's disease. Neurobiol Dis 2020; 144:105010. [PMID: 32682954 PMCID: PMC7365083 DOI: 10.1016/j.nbd.2020.105010] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 07/01/2020] [Accepted: 07/07/2020] [Indexed: 12/21/2022] Open
Abstract
Amyloid-β (Aβ) and tau proteins currently represent the two most promising targets to treat Alzheimer's disease. The most extensively developed method to treat the pathologic forms of these proteins is through the administration of exogenous antibodies, or passive immunotherapy. In this review, we discuss the molecular-level strategies that researchers are using to design an effective therapeutic antibody, given the challenges in treating this disease. These challenges include selectively targeting a protein that has misfolded or is pathological rather than the more abundant, healthy protein, designing strategic constructs for immunizing an animal to raise an antibody that has the appropriate conformational selectivity to achieve this end, and clearing the pathological protein species before prion-like cell-to-cell spread of misfolded protein has irreparably damaged neurons, without invoking damaging inflammatory responses in the brain that naturally arise when the innate immune system is clearing foreign agents. The various solutions to these problems in current clinical trials will be discussed.
Collapse
Affiliation(s)
- Steven S Plotkin
- University of British Columbia, Department of Physics and Astronomy and Genome Sciences and Technology Program, Vancouver, BC V6T 1Z1, Canada.
| | - Neil R Cashman
- University of British Columbia, Djavad Mowafaghian Centre for Brain Health, Vancouver, BC V6T 2B5, Canada.
| |
Collapse
|
237
|
Dragunow M. Human Brain Neuropharmacology: A Platform for Translational Neuroscience. Trends Pharmacol Sci 2020; 41:777-792. [PMID: 32994050 DOI: 10.1016/j.tips.2020.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/10/2020] [Accepted: 09/10/2020] [Indexed: 12/20/2022]
Abstract
Central nervous system (CNS) drug development has been plagued by a failure to translate effective therapies from the lab to the clinic. There are many potential reasons for this, including poor understanding of brain pharmacokinetic (PK) and pharmacodynamic (PD) factors, preclinical study flaws, clinical trial design issues, the complexity and variability of human brain diseases, as well as species differences. To address some of these problems, we have developed a platform for CNS drug discovery comprising: drug screening of primary adult human brain cells; human brain tissue microarray analysis of drug targets; and high-content phenotypic screening methods. In this opinion, I summarise the theoretical basis and the practical development and use of this platform in CNS drug discovery.
Collapse
Affiliation(s)
- Mike Dragunow
- Department of Pharmacology and Hugh Green Biobank, Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
| |
Collapse
|
238
|
Positron Emission Tomography in the Inflamed Cerebellum: Addressing Novel Targets among G Protein-Coupled Receptors and Immune Receptors. Pharmaceutics 2020; 12:pharmaceutics12100925. [PMID: 32998351 PMCID: PMC7601272 DOI: 10.3390/pharmaceutics12100925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/17/2020] [Accepted: 09/25/2020] [Indexed: 01/12/2023] Open
Abstract
Inflammatory processes preceding clinical manifestation of brain diseases are moving increasingly into the focus of positron emission tomographic (PET) investigations. A key role in inflammation and as a target of PET imaging efforts is attributed to microglia. Cerebellar microglia, with a predominant ameboid and activated subtype, is of special interest also regarding improved and changing knowledge on functional involvement of the cerebellum in mental activities in addition to its regulatory role in motor function. The present contribution considers small molecule ligands as potential PET tools for the visualization of several receptors recognized to be overexpressed in microglia and which can potentially serve as indicators of inflammatory processes in the cerebellum. The sphingosine 1 phosphate receptor 1 (S1P1), neuropeptide Y receptor 2 (NPY2) and purinoceptor Y12 (P2Y12) cannabinoid receptors and the chemokine receptor CX3CR1 as G-protein-coupled receptors and the ionotropic purinoceptor P2X7 provide structures with rather classical binding behavior, while the immune receptor for advanced glycation end products (RAGE) and the triggering receptor expressed on myeloid cells 2 (TREM2) might depend for instance on further accessory proteins. Improvement in differentiation between microglial functional subtypes in comparison to the presently used 18 kDa translocator protein ligands as well as of the knowledge on the role of polymorphisms are special challenges in such developments.
Collapse
|
239
|
Knapskog AB, Henjum K, Idland AV, Eldholm RS, Persson K, Saltvedt I, Watne LO, Engedal K, Nilsson LNG. Cerebrospinal fluid sTREM2 in Alzheimer's disease: comparisons between clinical presentation and AT classification. Sci Rep 2020; 10:15886. [PMID: 32985583 PMCID: PMC7522273 DOI: 10.1038/s41598-020-72878-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 09/04/2020] [Indexed: 12/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor expressed by microglia. Its cleaved fragments, soluble TREM2 (sTREM2), can be measured in the cerebrospinal fluid (CSF). Previous studies indicate higher CSF sTREM2 in symptomatic AD; however most of these studies have included biomarker positive AD cases and biomarker negative controls. The aim of the study was to explore potential differences in the CSF level of sTREM2 and factors associated with an increased sTREM2 level in patients diagnosed with mild cognitive impairment (MCI) or dementia due to AD compared with cognitively unimpaired controls as judged by clinical symptoms and biomarker category (AT). We included 299 memory clinic patients, 62 (20.7%) with AD-MCI and 237 (79.3%) with AD dementia, and 113 cognitively unimpaired controls. CSF measures of the core biomarkers were applied to determine AT status. CSF sTREM2 was analyzed by ELISA. Patients presented with comparable CSF sTREM2 levels as the cognitively unimpaired (9.6 ng/ml [SD 4.7] versus 8.8 ng/ml [SD 3.6], p = 0.27). We found that CSF sTREM2 associated with age-related neuroinflammation and tauopathy irrespectively of amyloid β, APOE ε4 status or gender. The findings were similar in both symptomatic and non-symptomatic individuals.
Collapse
Affiliation(s)
- Anne-Brita Knapskog
- Department of Geriatric Medicine, Memory Clinic, Oslo University Hospital, Ullevaal, Postboks 4956, Nydalen, 0424, Oslo, Norway.
| | - Kristi Henjum
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,Department of Geriatric Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ane-Victoria Idland
- Department of Geriatric Medicine, Memory Clinic, Oslo University Hospital, Ullevaal, Postboks 4956, Nydalen, 0424, Oslo, Norway.,Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Rannveig Sakshaug Eldholm
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Geriatrics, St Olavs Hospital, University Hospital of Trondheim, Trondheim, Norway
| | - Karin Persson
- Department of Geriatric Medicine, Memory Clinic, Oslo University Hospital, Ullevaal, Postboks 4956, Nydalen, 0424, Oslo, Norway.,Norwegian National Advisory Unit On Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway
| | - Ingvild Saltvedt
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,Department of Geriatrics, St Olavs Hospital, University Hospital of Trondheim, Trondheim, Norway
| | - Leiv Otto Watne
- Department of Geriatric Medicine, Memory Clinic, Oslo University Hospital, Ullevaal, Postboks 4956, Nydalen, 0424, Oslo, Norway
| | - Knut Engedal
- Department of Geriatric Medicine, Memory Clinic, Oslo University Hospital, Ullevaal, Postboks 4956, Nydalen, 0424, Oslo, Norway.,Norwegian National Advisory Unit On Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway
| | - Lars N G Nilsson
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| |
Collapse
|
240
|
Garcia-Leon JA, Caceres-Palomo L, Sanchez-Mejias E, Mejias-Ortega M, Nuñez-Diaz C, Fernandez-Valenzuela JJ, Sanchez-Varo R, Davila JC, Vitorica J, Gutierrez A. Human Pluripotent Stem Cell-Derived Neural Cells as a Relevant Platform for Drug Screening in Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21186867. [PMID: 32962164 PMCID: PMC7558359 DOI: 10.3390/ijms21186867] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 12/13/2022] Open
Abstract
Extracellular amyloid-beta deposition and intraneuronal Tau-laden neurofibrillary tangles are prime features of Alzheimer's disease (AD). The pathology of AD is very complex and still not fully understood, since different neural cell types are involved in the disease. Although neuronal function is clearly deteriorated in AD patients, recently, an increasing number of evidences have pointed towards glial cell dysfunction as one of the main causative phenomena implicated in AD pathogenesis. The complex disease pathology together with the lack of reliable disease models have precluded the development of effective therapies able to counteract disease progression. The discovery and implementation of human pluripotent stem cell technology represents an important opportunity in this field, as this system allows the generation of patient-derived cells to be used for disease modeling and therapeutic target identification and as a platform to be employed in drug discovery programs. In this review, we discuss the current studies using human pluripotent stem cells focused on AD, providing convincing evidences that this system is an excellent opportunity to advance in the comprehension of AD pathology, which will be translated to the development of the still missing effective therapies.
Collapse
Affiliation(s)
- Juan Antonio Garcia-Leon
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
- Correspondence: (J.A.G.-L.); (A.G.); Tel.: +34-952131935 (J.A.G.-L.); +34-952133344 (A.G.)
| | - Laura Caceres-Palomo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Elisabeth Sanchez-Mejias
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Marina Mejias-Ortega
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Cristina Nuñez-Diaz
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Juan Jose Fernandez-Valenzuela
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Raquel Sanchez-Varo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Jose Carlos Davila
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
| | - Javier Vitorica
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
- Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Instituto de Biomedicina de Sevilla (IBiS)-Hospital Universitario Virgen del Rocio/CSIC/Universidad de Sevilla, 41012 Sevilla, Spain
| | - Antonia Gutierrez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, 29071 Malaga, Spain; (L.C.-P.); (E.S.-M.); (M.M.-O.); (C.N.-D.); (J.J.F.-V.); (R.S.-V.); (J.C.D.)
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain;
- Correspondence: (J.A.G.-L.); (A.G.); Tel.: +34-952131935 (J.A.G.-L.); +34-952133344 (A.G.)
| |
Collapse
|
241
|
Gabr M, Rehman AU, Chen HF. Quinoline-Pyrazole Scaffold as a Novel Ligand of Galectin-3 and Suppressor of TREM2 Signaling. ACS Med Chem Lett 2020; 11:1759-1765. [PMID: 32944144 DOI: 10.1021/acsmedchemlett.0c00330] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022] Open
Abstract
Galectin-3 has been identified as a critical player in driving the neuroinflammatory responses in Alzheimer's disease (AD). A key feature of this function of galectin-3 is associated with its interaction with the triggering receptor expressed on myeloid cells-2 (TREM2). Herein, we report a high-throughput screening (HTS) platform that can be used for the identification of inhibitors of TREM2 and galectin-3 interaction. We have utilized this HTS assay to screen a focused library of compounds optimized for the central nervous system (CNS)-related diseases. MG-257 was identified from this screen as the first example of a small molecule that can attenuate TREM2 signaling based on its high affinity to galectin-3 (endogenous ligand of TREM2). Remarkably, MG-257 reduced the levels of proinflammatory cytokines in activated microglial cells, which highlights its ability to inhibit the neuroinflammatory response associated with AD.
Collapse
Affiliation(s)
- Moustafa Gabr
- Department of Radiology, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Ashfaq Ur Rehman
- Medicinal Bioinformatics Center, Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai 200025, China
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hai-Feng Chen
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, College of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Center for Bioinformation Technology, Shanghai 200235, China
| |
Collapse
|
242
|
Significance of Blood and Cerebrospinal Fluid Biomarkers for Alzheimer's Disease: Sensitivity, Specificity and Potential for Clinical Use. J Pers Med 2020; 10:jpm10030116. [PMID: 32911755 PMCID: PMC7565390 DOI: 10.3390/jpm10030116] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 08/21/2020] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is the most common type of dementia, affecting more than 5 million Americans, with steadily increasing mortality and incredible socio-economic burden. Not only have therapeutic efforts so far failed to reach significant efficacy, but the real pathogenesis of the disease is still obscure. The current theories are based on pathological findings of amyloid plaques and tau neurofibrillary tangles that accumulate in the brain parenchyma of affected patients. These findings have defined, together with the extensive neurodegeneration, the diagnostic criteria of the disease. The ability to detect changes in the levels of amyloid and tau in cerebrospinal fluid (CSF) first, and more recently in blood, has allowed us to use these biomarkers for the specific in-vivo diagnosis of AD in humans. Furthermore, other pathological elements of AD, such as the loss of neurons, inflammation and metabolic derangement, have translated to the definition of other CSF and blood biomarkers, which are not specific of the disease but, when combined with amyloid and tau, correlate with the progression from mild cognitive impairment to AD dementia, or identify patients who will develop AD pathology. In this review, we discuss the role of current and hypothetical biomarkers of Alzheimer's disease, their specificity, and the caveats of current high-sensitivity platforms for their peripheral detection.
Collapse
|
243
|
Agrawal I, Jha S. Mitochondrial Dysfunction and Alzheimer's Disease: Role of Microglia. Front Aging Neurosci 2020; 12:252. [PMID: 32973488 PMCID: PMC7468434 DOI: 10.3389/fnagi.2020.00252] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022] Open
Abstract
In 1907, Alois Alzheimer observed, as he quoted, development of "numerous fibers" and "adipose saccules" in the brain of his diseased patient Auguste Deter. The neurodegenerative disease became known as Alzheimer's disease (AD) and is the most common cause of dementia worldwide. AD normally develops with aging and is mostly initiated because of the imbalance between the formation and clearance of amyloid-β (Aβ). Formation of neurofibrillary tangles (NFTs) of hyperphosphorylated tau is another hallmark of AD. Neuroinflammation plays a significant role in the development and pathology of AD. This chapter explores the role of mitochondrial dysfunction in microglia in case of AD. Mitochondrial oxidative stress in microglia has been linked to the development of AD. Elevated generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential through various mechanisms have been observed in AD. Aβ interacts with microglial receptors, such as triggering receptor expressed in myeloid cells 2 (TREM2), activating downstream pathways causing mitochondrial damage and aggravating inflammation and cytotoxicity. Fibrillar Aβ activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in microglia leading to elevated induction of mitochondrial ROS which further causes neurotoxicity. Elevated ROS in microglia causes activation of inflammatory and cell death pathways. Production of ATP, regulation of mitochondrial health, autophagy, and mitophagy in microglia play significant roles in the AD pathology. Understanding microglial physiology and mitochondrial dysfunction will enable better therapeutic interventions.
Collapse
Affiliation(s)
- Ishan Agrawal
- Inflammation, Immunity and Tumour Biology Laboratory, Department of Bioscience and Bioengineering, Indian Institute of Technology (IIT) Jodhpur, Jodhpur, India
| | - Sushmita Jha
- Inflammation, Immunity and Tumour Biology Laboratory, Department of Bioscience and Bioengineering, Indian Institute of Technology (IIT) Jodhpur, Jodhpur, India
| |
Collapse
|
244
|
Simpson DSA, Oliver PL. ROS Generation in Microglia: Understanding Oxidative Stress and Inflammation in Neurodegenerative Disease. Antioxidants (Basel) 2020; 9:E743. [PMID: 32823544 PMCID: PMC7463655 DOI: 10.3390/antiox9080743] [Citation(s) in RCA: 419] [Impact Index Per Article: 104.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/06/2020] [Accepted: 08/08/2020] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders, such as Alzheimer's disease, are a global public health burden with poorly understood aetiology. Neuroinflammation and oxidative stress (OS) are undoubtedly hallmarks of neurodegeneration, contributing to disease progression. Protein aggregation and neuronal damage result in the activation of disease-associated microglia (DAM) via damage-associated molecular patterns (DAMPs). DAM facilitate persistent inflammation and reactive oxygen species (ROS) generation. However, the molecular mechanisms linking DAM activation and OS have not been well-defined; thus targeting these cells for clinical benefit has not been possible. In microglia, ROS are generated primarily by NADPH oxidase 2 (NOX2) and activation of NOX2 in DAM is associated with DAMP signalling, inflammation and amyloid plaque deposition, especially in the cerebrovasculature. Additionally, ROS originating from both NOX and the mitochondria may act as second messengers to propagate immune activation; thus intracellular ROS signalling may underlie excessive inflammation and OS. Targeting key kinases in the inflammatory response could cease inflammation and promote tissue repair. Expression of antioxidant proteins in microglia, such as NADPH dehydrogenase 1 (NQO1), is promoted by transcription factor Nrf2, which functions to control inflammation and limit OS. Lipid droplet accumulating microglia (LDAM) may also represent a double-edged sword in neurodegenerative disease by sequestering peroxidised lipids in non-pathological ageing but becoming dysregulated and pro-inflammatory in disease. We suggest that future studies should focus on targeted manipulation of NOX in the microglia to understand the molecular mechanisms driving inflammatory-related NOX activation. Finally, we discuss recent evidence that therapeutic target identification should be unbiased and founded on relevant pathophysiological assays to facilitate the discovery of translatable antioxidant and anti-inflammatory therapeutics.
Collapse
Affiliation(s)
- Dominic S. A. Simpson
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell, Oxfordshire OX11 0RD, UK;
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Peter L. Oliver
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell, Oxfordshire OX11 0RD, UK;
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| |
Collapse
|
245
|
TMEM59 interacts with TREM2 and modulates TREM2-dependent microglial activities. Cell Death Dis 2020; 11:678. [PMID: 32826884 PMCID: PMC7442838 DOI: 10.1038/s41419-020-02874-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 08/01/2020] [Accepted: 08/03/2020] [Indexed: 12/20/2022]
Abstract
The surface receptor triggering receptor expressed on myeloid cells 2 (TREM2) plays a crucial role in maintaining a multitude of microglial activities, such as survival, proliferation, migration, metabolism, inflammation, and phagocytosis. However, the molecular mechanisms underlying TREM2-mediated microglial activities remain largely elusive. Herein, we found that TREM2 interacted with the type I transmembrane protein TMEM59, whose expression could facilitate autophagic flux through its carboxyl-terminus. TMEM59 expression was decreased upon lipopolysaccharide treatment. While downregulation of TMEM59 promoted anti-inflammatory factor expression and attenuated lipopolysaccharide treatment-induced inflammation. Importantly, we found that overexpression of TREM2 reduced TMEM59 protein levels through promoting its degradation, whereas TMEM59 levels were elevated in Trem2-deficient microglia. Finally, impaired survival, proliferation, migration, and phagocytosis, as well as dysregulated autophagy and metabolism in Trem2-deficient microglia were attenuated upon TMEM59 silencing. Together, our findings reveal a novel function of TREM2 in mediating TMEM59 protein degradation and demonstrate the importance of TMEM59 homeostasis in maintaining TREM2-mediated microglial activities.
Collapse
|
246
|
Belayev L, Hong SH, Freitas RS, Menghani H, Marcell SJ, Khoutorova L, Mukherjee PK, Reid MM, Oria RB, Bazan NG. DHA modulates MANF and TREM2 abundance, enhances neurogenesis, reduces infarct size, and improves neurological function after experimental ischemic stroke. CNS Neurosci Ther 2020; 26:1155-1167. [PMID: 32757264 PMCID: PMC7564189 DOI: 10.1111/cns.13444] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023] Open
Abstract
Aims Mesencephalic astrocyte‐derived neurotrophic factor (MANF) is a secretory neurotrophic factor protein that promotes repair after neuronal injury. The microglia cell surface receptor (triggering receptor expressed on myeloid cells‐2; TREM2) regulates the production of pro‐ and antiinflammatory mediators after stroke. Here, we study MANF and TREM2 expression after middle cerebral artery occlusion (MCAo) and explore if docosahexaenoic acid (DHA) treatment exerts a potentiating effect. Methods We used 2 hours of the MCAo model in rats and intravenously administered DHA or vehicle at 3 hours after the onset of MCAo. Neurobehavioral assessment was performed on days 1, 3, 7, and 14; MANF and TREM2 expression was measured by immunohistochemistry and Western blotting. Results MANF was upregulated in neurons and astrocytes on days 1, 7, and 14, and TREM2 was expressed on macrophages in the ischemic penumbra and dentate gyrus (DG) on days 7 and 14. DHA improved neurobehavioral recovery, attenuated infarct size on days 7 and 14, increased MANF and decreased TREM2 expression in ischemic core, penumbra, DG, and enhanced neurogenesis on Day 14. Conclusion MANF and TREM2 protein abundance is robustly increased after MCAo, and DHA treatment potentiated MANF abundance, decreased TREM2 expression, improved neurobehavioral recovery, reduced infarction, and provided enhanced neuroprotection.
Collapse
Affiliation(s)
- Ludmila Belayev
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Sung-Ha Hong
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Raul S Freitas
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Hemant Menghani
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Shawn J Marcell
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Larissa Khoutorova
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Pranab K Mukherjee
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Madigan M Reid
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Reinaldo B Oria
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, USA
| |
Collapse
|
247
|
Guan YF, Huang GB, Xu MD, Gao F, Lin S, Huang J, Wang J, Li YQ, Wu CH, Yao S, Wang Y, Zhang YL, Teoh JP, Xuan A, Sun XD. Anti-depression effects of ketogenic diet are mediated via the restoration of microglial activation and neuronal excitability in the lateral habenula. Brain Behav Immun 2020; 88:748-762. [PMID: 32413556 DOI: 10.1016/j.bbi.2020.05.032] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/03/2020] [Accepted: 05/09/2020] [Indexed: 12/14/2022] Open
Abstract
Depression is a severe neuropsychiatric disorder, of which the underlying pathological mechanisms remain unclear. The ketogenic diet (KD) has been reported to exhibit preventative effects on depressive-like behaviors in rodents. However, the therapeutic effects of KD on depressive-like behaviors have not been illustrated thus far. Here, we found that KD treatment dramatically ameliorated depressive-like behaviors in both repeated social defeat stress (R-SDS) and lipopolysaccharide (LPS) models, indicating the potential therapeutic effects of KD on depression. Our electrophysiological studies further showed that neuronal excitability was increased in the lateral habenula (LHb) of mice exposed to R-SDS or LPS, which can be reversed in the presence of KD treatment. Moreover, R-SDS and LPS were also found to induce robust microglial inflammatory activation in the LHb. Importantly, these phenotypes were rescued in mice fed with KD. In addition, we found that the protein level of innate immune receptor Trem2 in the LHb was significantly decreased in depression models. Specific knockdown of Trem2 in LHb microglia induced depressive-like behaviors, increased neuronal excitability as well as robust microglial inflammatory activation. Altogether, we demonstrated the therapeutic effects of KD on depressive-like behaviors, which are probably mediated via the restoration of microglial inflammatory activation and neuronal excitability. Besides, we also proposed an unrecognized function of Trem2 in the LHb for depression. Our study sheds light on the pathogenesis of depression and thereby offers a potential therapeutic intervention.
Collapse
Affiliation(s)
- Yan-Fei Guan
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Guo-Bin Huang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Min-Dong Xu
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Feng Gao
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Song Lin
- Department of Physiology, School of Medicine, Jinan University, Guangzhou 510632, China
| | - Jie Huang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Jin Wang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yuan-Quan Li
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Cui-Hong Wu
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Shan Yao
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Ying Wang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Yun-Long Zhang
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Jian-Peng Teoh
- Department of Gynecology and Obstetrics, the Sixth Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China
| | - Aiguo Xuan
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China.
| | - Xiang-Dong Sun
- School of Basic Medical Sciences, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China; Guangdong Province Key Laboratory of Psychiatric Disorders, Southern Medical University, Guangzhou 510515, China.
| |
Collapse
|
248
|
Guo T, Zhang D, Zeng Y, Huang TY, Xu H, Zhao Y. Molecular and cellular mechanisms underlying the pathogenesis of Alzheimer's disease. Mol Neurodegener 2020; 15:40. [PMID: 32677986 PMCID: PMC7364557 DOI: 10.1186/s13024-020-00391-7] [Citation(s) in RCA: 423] [Impact Index Per Article: 105.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 06/17/2020] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disorder seen in age-dependent dementia. There is currently no effective treatment for AD, which may be attributed in part to lack of a clear underlying mechanism. Studies within the last few decades provide growing evidence for a central role of amyloid β (Aβ) and tau, as well as glial contributions to various molecular and cellular pathways in AD pathogenesis. Herein, we review recent progress with respect to Aβ- and tau-associated mechanisms, and discuss glial dysfunction in AD with emphasis on neuronal and glial receptors that mediate Aβ-induced toxicity. We also discuss other critical factors that may affect AD pathogenesis, including genetics, aging, variables related to environment, lifestyle habits, and describe the potential role of apolipoprotein E (APOE), viral and bacterial infection, sleep, and microbiota. Although we have gained much towards understanding various aspects underlying this devastating neurodegenerative disorder, greater commitment towards research in molecular mechanism, diagnostics and treatment will be needed in future AD research.
Collapse
Affiliation(s)
- Tiantian Guo
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Denghong Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China
| | - Yuzhe Zeng
- Department of Orthopaedics, Orthopaedic Center of People's Liberation Army, The Affiliated Southeast Hospital of Xiamen University, Zhangzhou, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
| | - Yingjun Zhao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, China.
| |
Collapse
|
249
|
Liccardo D, Marzano F, Carraturo F, Guida M, Femminella GD, Bencivenga L, Agrimi J, Addonizio A, Melino I, Valletta A, Rengo C, Ferrara N, Rengo G, Cannavo A. Potential Bidirectional Relationship Between Periodontitis and Alzheimer's Disease. Front Physiol 2020; 11:683. [PMID: 32719612 PMCID: PMC7348667 DOI: 10.3389/fphys.2020.00683] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/26/2020] [Indexed: 12/15/2022] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent form of dementia in the elderly population, representing a global public health priority. Despite a large improvement in understanding the pathogenesis of AD, the etiology of this disorder remains still unclear, and no current treatment is able to prevent, slow, or stop its progression. Thus, there is a keen interest in the identification and modification of the risk factors and novel molecular mechanisms associated with the development and progression of AD. In this context, it is worth noting that several findings support the existence of a direct link between neuronal and non-neuronal inflammation/infection and AD progression. Importantly, recent studies are now supporting the existence of a direct relationship between periodontitis, a chronic inflammatory oral disease, and AD. The mechanisms underlying the association remain to be fully elucidated, however, it is generally accepted, although not confirmed, that oral pathogens can penetrate the bloodstream, inducing a low-grade systemic inflammation that negatively affects brain function. Indeed, a recent report demonstrated that oral pathogens and their toxic proteins infect the brain of AD patients. For instance, when AD progresses from the early to the more advanced stages, patients could no longer be able to adequately adhere to proper oral hygiene practices, thus leading to oral dysbiosis that, in turn, fuels infection, such as periodontitis. Therefore, in this review, we will provide an update on the emerging (preclinical and clinical) evidence that supports the relationship existing between periodontitis and AD. More in detail, we will discuss data attesting that periodontitis and AD share common risk factors and a similar hyper-inflammatory phenotype.
Collapse
Affiliation(s)
- Daniela Liccardo
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy.,Center for Translational Medicine, Temple University, Philadelphia, PA, United States
| | - Federica Marzano
- Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy
| | | | - Marco Guida
- Department of Biology, University of Naples Federico II, Naples, Italy
| | | | - Leonardo Bencivenga
- Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, Italy
| | - Jacopo Agrimi
- Division of Cardiology, Johns Hopkins University, Baltimore, MD, United States
| | - Armida Addonizio
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Imma Melino
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Alessandra Valletta
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy
| | - Carlo Rengo
- Department of Prosthodontics and Dental Materials, School of Dental Medicine, University of Siena, Siena, Italy
| | - Nicola Ferrara
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy.,Istituti Clinici Scientifici ICS Maugeri - S.p.A.-Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Scientifico di Telese Terme, Telese, Italy
| | - Giuseppe Rengo
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy.,Istituti Clinici Scientifici ICS Maugeri - S.p.A.-Istituti di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Scientifico di Telese Terme, Telese, Italy
| | - Alessandro Cannavo
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy.,Task Force on Microbiome Studies, University of Naples Federico II, Naples, Italy
| |
Collapse
|
250
|
Deczkowska A, Weiner A, Amit I. The Physiology, Pathology, and Potential Therapeutic Applications of the TREM2 Signaling Pathway. Cell 2020; 181:1207-1217. [DOI: 10.1016/j.cell.2020.05.003] [Citation(s) in RCA: 143] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/15/2020] [Accepted: 04/30/2020] [Indexed: 12/20/2022]
|