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Li Z, Wu H, Luo Y, Tan X. Correlation of serum complement factor 5a level with inflammatory response and cognitive function in patients with Alzheimer's disease of different severity. BMC Neurol 2023; 23:319. [PMID: 37679689 PMCID: PMC10483705 DOI: 10.1186/s12883-023-03256-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/22/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a common cause of dementia. Serum complement factor 5a (C5a) is exceedingly implicated in AD. We explored the role of C5a levels in AD patients of different severity. METHODS Mild, moderate, and severe AD patients, and healthy controls were included. C5a and pro-inflammatory factor (TNF-α, IL-1β, IL-6, CRP) levels were assessed by ELISA, and cognitive function was evaluated by Mini-Mental state examination (MMSE) score. The correlations between C5a, inflammatory factor levels, MMSE score, and plasma Aβ42/Aβ40 ratio were analyzed by Pearson tests. Independent risk factors for AD aggravation were assessed by logistic multivariate regression analysis. According to the cut-off value of receiver operating characteristic (ROC) curve analysis of C5a level, AD patients were assigned into low/high expression groups, and severe AD incidence was compared. Severe AD cumulative incidence was analyzed by Kaplan-Meier curve. RESULTS Serum C5a, TNF-α, IL-1β, IL-6 and CRP levels were raised, and MMSE score was lowered in AD. Serum C5a, TNF-α, IL-1β, IL-6 and CRP levels in severe AD patients were higher than those in mild/moderate AD patients, but there were no significant differences in these cytokines between moderate and mild AD groups. The MMSE score of severe AD patients was lower than that of mild/moderate AD patients. Serum C5a level was positively correlated with serum TNF-α, IL-1β, IL-6, and CRP levels, and negatively correlated with MMSE score, with no obvious correlation with plasma Aβ42/Aβ40 ratio. Serum C5a level was one of the independent risk factors for AD aggravation. The occurrence of severe AD might be related to an increase in serum C5a level. CONCLUSION Serum C5a level increased with AD severity, and its expression was positively correlated with serum pro-inflammatory factor levels, and negatively correlated with cognitive function.
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Affiliation(s)
- Zhilian Li
- Department of Neurology, The First People´s Hospital of Jingzhou City, No.8 HangKong Road, Shashi District, 434100, Jingzhou City, Hubei Province, P.R. China
| | - Huifang Wu
- Yangtze University, 434023, Jingzhou City, Hubei Province, P.R. China.
| | - Yi Luo
- Department of Neurology, The First People´s Hospital of Jingzhou City, No.8 HangKong Road, Shashi District, 434100, Jingzhou City, Hubei Province, P.R. China
| | - Xianpei Tan
- Department of Neurology, The First People´s Hospital of Jingzhou City, No.8 HangKong Road, Shashi District, 434100, Jingzhou City, Hubei Province, P.R. China
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2
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Wang N, Wang M, Jeevaratnam S, Rosenberg C, Ikezu TC, Shue F, Doss SV, Alnobani A, Martens YA, Wren M, Asmann YW, Zhang B, Bu G, Liu CC. Opposing effects of apoE2 and apoE4 on microglial activation and lipid metabolism in response to demyelination. Mol Neurodegener 2022; 17:75. [PMID: 36419137 PMCID: PMC9682675 DOI: 10.1186/s13024-022-00577-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 10/21/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Abnormal lipid accumulation has been recognized as a key element of immune dysregulation in microglia whose dysfunction contributes to neurodegenerative diseases. Microglia play essential roles in the clearance of lipid-rich cellular debris upon myelin damage or demyelination, a common pathogenic event in neuronal disorders. Apolipoprotein E (apoE) plays a pivotal role in brain lipid homeostasis; however, the apoE isoform-dependent mechanisms regulating microglial response upon demyelination remain unclear. METHODS To determine how apoE isoforms impact microglial response to myelin damage, 2-month-old apoE2-, apoE3-, and apoE4-targeted replacement (TR) mice were fed with normal diet (CTL) or 0.2% cuprizone (CPZ) diet for four weeks to induce demyelination in the brain. To examine the effects on subsequent remyelination, the cuprizone diet was switched back to regular chow for an additional two weeks. After treatment, brains were collected and subjected to immunohistochemical and biochemical analyses to assess the myelination status, microglial responses, and their capacity for myelin debris clearance. Bulk RNA sequencing was performed on the corpus callosum (CC) to address the molecular mechanisms underpinning apoE-mediated microglial activation upon demyelination. RESULTS We demonstrate dramatic isoform-dependent differences in the activation and function of microglia upon cuprizone-induced demyelination. ApoE2 microglia were hyperactive and more efficient in clearing lipid-rich myelin debris, whereas apoE4 microglia displayed a less activated phenotype with reduced clearance efficiency, compared with apoE3 microglia. Transcriptomic profiling revealed that key molecules known to modulate microglial functions had differential expression patterns in an apoE isoform-dependent manner. Importantly, apoE4 microglia had excessive buildup of lipid droplets, consistent with an impairment in lipid metabolism, whereas apoE2 microglia displayed a superior ability to metabolize myelin enriched lipids. Further, apoE2-TR mice had a greater extent of remyelination; whereas remyelination was compromised in apoE4-TR mice. CONCLUSIONS Our findings provide critical mechanistic insights into how apoE isoforms differentially regulate microglial function and the maintenance of myelin dynamics, which may inform novel therapeutic avenues for targeting microglial dysfunctions in neurodegenerative diseases.
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Affiliation(s)
- Na Wang
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Minghui Wang
- grid.59734.3c0000 0001 0670 2351Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029 USA
| | - Suren Jeevaratnam
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Cassandra Rosenberg
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Tadafumi C. Ikezu
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Francis Shue
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Sydney V. Doss
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Alla Alnobani
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Yuka A. Martens
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Melissa Wren
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Yan W. Asmann
- grid.417467.70000 0004 0443 9942Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Bin Zhang
- grid.59734.3c0000 0001 0670 2351Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029 USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
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3
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Fernández-Calle R, Konings SC, Frontiñán-Rubio J, García-Revilla J, Camprubí-Ferrer L, Svensson M, Martinson I, Boza-Serrano A, Venero JL, Nielsen HM, Gouras GK, Deierborg T. APOE in the bullseye of neurodegenerative diseases: impact of the APOE genotype in Alzheimer's disease pathology and brain diseases. Mol Neurodegener 2022; 17:62. [PMID: 36153580 PMCID: PMC9509584 DOI: 10.1186/s13024-022-00566-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 08/29/2022] [Indexed: 02/06/2023] Open
Abstract
ApoE is the major lipid and cholesterol carrier in the CNS. There are three major human polymorphisms, apoE2, apoE3, and apoE4, and the genetic expression of APOE4 is one of the most influential risk factors for the development of late-onset Alzheimer's disease (AD). Neuroinflammation has become the third hallmark of AD, together with Amyloid-β plaques and neurofibrillary tangles of hyperphosphorylated aggregated tau protein. This review aims to broadly and extensively describe the differential aspects concerning apoE. Starting from the evolution of apoE to how APOE's single-nucleotide polymorphisms affect its structure, function, and involvement during health and disease. This review reflects on how APOE's polymorphisms impact critical aspects of AD pathology, such as the neuroinflammatory response, particularly the effect of APOE on astrocytic and microglial function and microglial dynamics, synaptic function, amyloid-β load, tau pathology, autophagy, and cell-cell communication. We discuss influential factors affecting AD pathology combined with the APOE genotype, such as sex, age, diet, physical exercise, current therapies and clinical trials in the AD field. The impact of the APOE genotype in other neurodegenerative diseases characterized by overt inflammation, e.g., alpha- synucleinopathies and Parkinson's disease, traumatic brain injury, stroke, amyotrophic lateral sclerosis, and multiple sclerosis, is also addressed. Therefore, this review gathers the most relevant findings related to the APOE genotype up to date and its implications on AD and CNS pathologies to provide a deeper understanding of the knowledge in the APOE field.
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Affiliation(s)
- Rosalía Fernández-Calle
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Sabine C. Konings
- Department of Experimental Medical Science, Experimental Dementia Research Unit, Lund University, Lund, Sweden
| | - Javier Frontiñán-Rubio
- Oxidative Stress and Neurodegeneration Group, Faculty of Medicine, Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Juan García-Revilla
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
- Departamento de Bioquímica Y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Lluís Camprubí-Ferrer
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Martina Svensson
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Isak Martinson
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
| | - Antonio Boza-Serrano
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
- Departamento de Bioquímica Y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - José Luís Venero
- Departamento de Bioquímica Y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, and Instituto de Biomedicina de Sevilla-Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Henrietta M. Nielsen
- Department of Biochemistry and Biophysics at, Stockholm University, Stockholm, Sweden
| | - Gunnar K. Gouras
- Department of Experimental Medical Science, Experimental Dementia Research Unit, Lund University, Lund, Sweden
| | - Tomas Deierborg
- Department of Experimental Medical Science, Experimental Neuroinflammation Laboratory, Lund University, Lund, Sweden
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4
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Yu F, Wang Y, Stetler AR, Leak RK, Hu X, Chen J. Phagocytic microglia and macrophages in brain injury and repair. CNS Neurosci Ther 2022; 28:1279-1293. [PMID: 35751629 PMCID: PMC9344092 DOI: 10.1111/cns.13899] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/31/2022] [Accepted: 06/04/2022] [Indexed: 12/21/2022] Open
Abstract
AIMS Phagocytosis is the cellular digestion of extracellular particles, such as pathogens and dying cells, and is a key element in the evolution of central nervous system (CNS) disorders. Microglia and macrophages are the professional phagocytes of the CNS. By clearing toxic cellular debris and reshaping the extracellular matrix, microglia/macrophages help pilot the brain repair and functional recovery process. However, CNS resident and invading immune cells can also magnify tissue damage by igniting runaway inflammation and phagocytosing stressed-but viable-neurons. DISCUSSION Microglia/macrophages help mediate intercellular communication and react quickly to the "find-me" signals expressed by dead/dying neurons. The activated microglia/macrophages then migrate to the injury site to initiate the phagocytic process upon encountering "eat-me" signals on the surfaces of endangered cells. Thus, healthy cells attempt to avoid inappropriate engulfment by expressing "do not-eat-me" signals. Microglia/macrophages also have the capacity to phagocytose immune cells that invade the injured brain (e.g., neutrophils) and to regulate their pro-inflammatory properties. During brain recovery, microglia/macrophages engulf myelin debris, initiate synaptogenesis and neurogenesis, and sculpt a favorable extracellular matrix to support network rewiring, among other favorable roles. Here, we review the multilayered nature of phagocytotic microglia/macrophages, including the molecular and cellular mechanisms that govern microglia/macrophage-induced phagocytosis in acute brain injury, and discuss strategies that tap into the therapeutic potential of this engulfment process. CONCLUSION Identification of biological targets that can temper neuroinflammation after brain injury without hindering the essential phagocytic functions of microglia/macrophages will expedite better medical management of the stroke recovery stage.
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Affiliation(s)
- Fang Yu
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Yangfan Wang
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Anne R. Stetler
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Rehana K. Leak
- Graduate School of Pharmaceutical SciencesSchool of Pharmacy, Duquesne UniversityPittsburghPennsylvaniaUSA
| | - Xiaoming Hu
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jun Chen
- Geriatric Research, Education and Clinical CenterVeterans Affairs Pittsburgh Health Care SystemPittsburghPennsylvaniaUSA
- Pittsburgh Institute of Brain Disorders & Recovery and Department of NeurologyUniversity of PittsburghPittsburghPennsylvaniaUSA
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5
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Houle S, Kokiko-Cochran ON. A Levee to the Flood: Pre-injury Neuroinflammation and Immune Stress Influence Traumatic Brain Injury Outcome. Front Aging Neurosci 2022; 13:788055. [PMID: 35095471 PMCID: PMC8790486 DOI: 10.3389/fnagi.2021.788055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
Increasing evidence demonstrates that aging influences the brain's response to traumatic brain injury (TBI), setting the stage for neurodegenerative pathology like Alzheimer's disease (AD). This topic is often dominated by discussions of post-injury aging and inflammation, which can diminish the consideration of those same factors before TBI. In fact, pre-TBI aging and inflammation may be just as critical in mediating outcomes. For example, elderly individuals suffer from the highest rates of TBI of all severities. Additionally, pre-injury immune challenges or stressors may alter pathology and outcome independent of age. The inflammatory response to TBI is malleable and influenced by previous, coincident, and subsequent immune insults. Therefore, pre-existing conditions that elicit or include an inflammatory response could substantially influence the brain's ability to respond to traumatic injury and ultimately affect chronic outcome. The purpose of this review is to detail how age-related cellular and molecular changes, as well as genetic risk variants for AD affect the neuroinflammatory response to TBI. First, we will review the sources and pathology of neuroinflammation following TBI. Then, we will highlight the significance of age-related, endogenous sources of inflammation, including changes in cytokine expression, reactive oxygen species processing, and mitochondrial function. Heightened focus is placed on the mitochondria as an integral link between inflammation and various genetic risk factors for AD. Together, this review will compile current clinical and experimental research to highlight how pre-existing inflammatory changes associated with infection and stress, aging, and genetic risk factors can alter response to TBI.
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Affiliation(s)
- Samuel Houle
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States,Institute for Behavioral Medicine Research, Neurological Institute, The Ohio State University, Columbus, OH, United States
| | - Olga N. Kokiko-Cochran
- Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, United States,Institute for Behavioral Medicine Research, Neurological Institute, The Ohio State University, Columbus, OH, United States,*Correspondence: Olga N. Kokiko-Cochran
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6
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Chen Y, Hong T, Chen F, Sun Y, Wang Y, Cui L. Interplay Between Microglia and Alzheimer's Disease-Focus on the Most Relevant Risks: APOE Genotype, Sex and Age. Front Aging Neurosci 2021; 13:631827. [PMID: 33897406 PMCID: PMC8060487 DOI: 10.3389/fnagi.2021.631827] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/18/2021] [Indexed: 12/20/2022] Open
Abstract
As the main immune cells of the central nervous system (CNS), microglia regulates normal development, homeostasis and general brain physiology. These functions put microglia at the forefront of CNS repair and recovery. Uncontrolled activation of microglia is related to the course of neurodegenerative diseases such as Alzheimer’s disease. It is clear that the classic pathologies of amyloid β (Aβ) and Tau are usually accompanied by the activation of microglia, and the activation of microglia also serves as an early event in the pathogenesis of AD. Therefore, during the occurrence and development of AD, the key susceptibility factors for AD—apolipoprotein E (APOE) genotype, sex and age—may further interact with microglia to exacerbate neurodegeneration. In this review, we discuss the role of microglia in the progression of AD related to the three risk factors for AD: APOE genotype, sex and aging. APOE-expressing microglia accumulates around Aβ plaques, and the presence of APOE4 may disrupt the phagocytosis of Aβ aggregates and aggravate neurodegeneration in Tau disease models. In addition, females have a high incidence of AD, and normal female microglia and estrogen have protective effects under normal conditions. However, under the influence of AD, female microglia seem to lose their protective effect and instead accelerate the course of AD. Aging, another major risk factor, may increase the sensitivity of microglia, leading to the exacerbation of microglial dysfunction in elderly AD. Obviously, in the role of microglia in AD, the three main risk factors of APOE, sex, and aging are not independent and have synergistic effects that contribute to the risk of AD. Moreover, new microglia can replace dysfunctional microglia after microglial depletion, which is a new promising strategy for AD treatment.
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Affiliation(s)
- Yanting Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Tingting Hong
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Feng Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yuanhong Sun
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Yan Wang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Department of Neurology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
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7
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Abstract
A major feature of neurodegeneration is disruption of central nervous system homeostasis, during which microglia play diverse roles. In the central nervous system, microglia serve as the first line of immune defense and function in synapse pruning, injury repair, homeostasis maintenance, and regulation of brain development through scavenging and phagocytosis. Under pathological conditions or various stimulations, microglia proliferate, aggregate, and undergo a variety of changes in cell morphology, immunophenotype, and function. This review presents the features of microglia, especially their diversity and ability to change dynamically, and reinterprets their role as sensors for multiple stimulations and as effectors for brain aging and neurodegeneration. This review also summarizes some therapeutic approaches for neurodegenerative diseases that target microglia.
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Affiliation(s)
- Yu Xu
- Department of Anesthesiology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Embryo Original Disease, Shanghai Municipal Key Clinical Specialty; Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ming-Zhu Jin
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ze-Yong Yang
- Department of Anesthesiology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Embryo Original Disease, Shanghai Municipal Key Clinical Specialty, Shanghai, China
| | - Wei-Lin Jin
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electronic Engineering; National Centers for Translational Medicine, Shanghai Jiao Tong University, Shanghai; Shaanxi Key Laboratory of Brain Disorders & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, Shaanxi Province, China
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8
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Najm R, Zalocusky KA, Zilberter M, Yoon SY, Hao Y, Koutsodendris N, Nelson M, Rao A, Taubes A, Jones EA, Huang Y. In Vivo Chimeric Alzheimer's Disease Modeling of Apolipoprotein E4 Toxicity in Human Neurons. Cell Rep 2020; 32:107962. [PMID: 32726626 PMCID: PMC7430173 DOI: 10.1016/j.celrep.2020.107962] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/15/2020] [Accepted: 07/03/2020] [Indexed: 02/08/2023] Open
Abstract
Despite its clear impact on Alzheimer's disease (AD) risk, apolipoprotein (apo) E4's contributions to AD etiology remain poorly understood. Progress in answering this and other questions in AD research has been limited by an inability to model human-specific phenotypes in an in vivo environment. Here we transplant human induced pluripotent stem cell (hiPSC)-derived neurons carrying normal apoE3 or pathogenic apoE4 into human apoE3 or apoE4 knockin mouse hippocampi, enabling us to disentangle the effects of apoE4 produced in human neurons and in the brain environment. Using single-nucleus RNA sequencing (snRNA-seq), we identify key transcriptional changes specific to human neuron subtypes in response to endogenous or exogenous apoE4. We also find that Aβ from transplanted human neurons forms plaque-like aggregates, with differences in localization and interaction with microglia depending on the transplant and host apoE genotype. These findings highlight the power of in vivo chimeric disease modeling for studying AD.
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Affiliation(s)
- Ramsey Najm
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kelly A Zalocusky
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Gladstone Center for Translational Advancement, San Francisco, CA 94158, USA
| | - Misha Zilberter
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Seo Yeon Yoon
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Yanxia Hao
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Gladstone Center for Translational Advancement, San Francisco, CA 94158, USA
| | - Nicole Koutsodendris
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Maxine Nelson
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Antara Rao
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alice Taubes
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Emily A Jones
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Gladstone Center for Translational Advancement, San Francisco, CA 94158, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA; Departments of Neurology and Pathology, University of California, San Francisco, San Francisco, CA 94143, USA.
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9
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Graykowski D, Kasparian K, Caniglia J, Gritsaeva Y, Cudaback E. Neuroinflammation drives APOE genotype-dependent differential expression of neprilysin. J Neuroimmunol 2020; 346:577315. [PMID: 32682137 DOI: 10.1016/j.jneuroim.2020.577315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/28/2020] [Accepted: 06/29/2020] [Indexed: 02/04/2023]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by the deposition of amyloid-beta (Aβ) plaques and widespread neuroinflammation. While the cause of AD remains unknown, multiple factors likely contribute to the disease, including heart disease, diabetes, previous head injury, as well as a number of genetic determinants. Inheritance of the apolipoprotein (APOE) ε4 allele represents the strongest genetic risk factor for development of AD, driving pathogenesis and increasing overall disease severity. APOE has long been recognized as a key regulator of cholesterol homeostasis, although a greater appreciation now exists for its role in various innate immune system processes. Indeed, APOE modulates inflammatory environments in brain in large part by altering gene expression profiles in glia, important mediators of immunity in the CNS. While the association between APOE and AD was first observed nearly three decades ago, the mechanism by which APOE ε4 influences the etiology and pathophysiology of AD is not well characterized. Overwhelming data supports the hypothesis that APOE ε4 dysregulates central amyloid metabolism by an undetermined molecular mechanism, thus laying the foundation for disease. A host of amyloid-degrading enzymes (ADEs) regulate Aβ accumulation in brain, and therefore represent valuable therapeutic targets. Neprilysin (NEP), a metalloendopeptidase expressed by activated microglia and astrocytes, is a broad-spectrum ADE able to degrade a variety of Aβ species. Here we describe in vivo and in vitro experiments designed to investigate the potential for APOE genotype to differentially regulate glial NEP in brain under neuroinflammatory conditions. Our results provide a novel mechanism by which APOE genotype-dependent differential expression of NEP by glia during neuroinflammation may contribute to AD pathogenesis.
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Affiliation(s)
- David Graykowski
- Department of Health Sciences, DePaul University, Chicago, IL 60614, USA
| | - Kyle Kasparian
- Department of Health Sciences, DePaul University, Chicago, IL 60614, USA
| | - John Caniglia
- Department of Health Sciences, DePaul University, Chicago, IL 60614, USA
| | - Yelena Gritsaeva
- Department of Health Sciences, DePaul University, Chicago, IL 60614, USA
| | - Eiron Cudaback
- Department of Health Sciences, DePaul University, Chicago, IL 60614, USA.
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10
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Najm R, Jones EA, Huang Y. Apolipoprotein E4, inhibitory network dysfunction, and Alzheimer's disease. Mol Neurodegener 2019; 14:24. [PMID: 31186040 PMCID: PMC6558779 DOI: 10.1186/s13024-019-0324-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 05/23/2019] [Indexed: 02/08/2023] Open
Abstract
Apolipoprotein (apo) E4 is the major genetic risk factor for Alzheimer's disease (AD), increasing risk and decreasing age of disease onset. Many studies have demonstrated the detrimental effects of apoE4 in varying cellular contexts. However, the underlying mechanisms explaining how apoE4 leads to cognitive decline are not fully understood. Recently, the combination of human induced pluripotent stem cell (hiPSC) modeling of neurological diseases in vitro and electrophysiological studies in vivo have begun to unravel the intersection between apoE4, neuronal subtype dysfunction or loss, subsequent network deficits, and eventual cognitive decline. In this review, we provide an overview of the literature describing apoE4's detrimental effects in the central nervous system (CNS), specifically focusing on its contribution to neuronal subtype dysfunction or loss. We focus on γ-aminobutyric acid (GABA)-expressing interneurons in the hippocampus, which are selectively vulnerable to apoE4-mediated neurotoxicity. Additionally, we discuss the importance of the GABAergic inhibitory network to proper cognitive function and how dysfunction of this network manifests in AD. Finally, we examine how apoE4-mediated GABAergic interneuron loss can lead to inhibitory network deficits and how this deficit results in cognitive decline. We propose the following working model: Aging and/or stress induces neuronal expression of apoE. GABAergic interneurons are selectively vulnerable to intracellularly produced apoE4, through a tau dependent mechanism, which leads to their dysfunction and eventual death. In turn, GABAergic interneuron loss causes hyperexcitability and dysregulation of neural networks in the hippocampus and cortex. This dysfunction results in learning, memory, and other cognitive deficits that are the central features of AD.
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Affiliation(s)
- Ramsey Najm
- Gladstone Institute of Neurological Disease, San Francisco, CA, 94158, USA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA, 94143, USA
| | - Emily A Jones
- Gladstone Institute of Neurological Disease, San Francisco, CA, 94158, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, 94143, USA
| | - Yadong Huang
- Gladstone Institute of Neurological Disease, San Francisco, CA, 94158, USA.
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA, 94143, USA.
- Biomedical Sciences Graduate Program, University of California, San Francisco, CA, 94143, USA.
- Department of Neurology, University of California, San Francisco, CA, 94143, USA.
- Department of Pathology, University of California, San Francisco, CA, 94143, USA.
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11
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Tzioras M, Davies C, Newman A, Jackson R, Spires‐Jones T. Invited Review: APOE at the interface of inflammation, neurodegeneration and pathological protein spread in Alzheimer's disease. Neuropathol Appl Neurobiol 2019; 45:327-346. [PMID: 30394574 PMCID: PMC6563457 DOI: 10.1111/nan.12529] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 10/27/2018] [Indexed: 12/13/2022]
Abstract
Despite more than a century of research, the aetiology of sporadic Alzheimer's disease (AD) remains unclear and finding disease modifying treatments for AD presents one of the biggest medical challenges of our time. AD pathology is characterized by deposits of aggregated amyloid beta (Aβ) in amyloid plaques and aggregated tau in neurofibrillary tangles. These aggregates begin in distinct brain regions and spread throughout the brain in stereotypical patterns. Neurodegeneration, comprising loss of synapses and neurons, occurs in brain regions with high tangle pathology, and an inflammatory response of glial cells appears in brain regions with pathological aggregates. Inheriting an apolipoprotein E ε4 (APOE4) allele strongly increases the risk of developing AD for reasons that are not yet entirely clear. Substantial amounts of evidence support a role for APOE in modulating the aggregation and clearance of Aβ, and data have been accumulating recently implicating APOE4 in exacerbating neurodegeneration, tau pathology and inflammation. We hypothesize that APOE4 influences all the pathological hallmarks of AD and may sit at the interface between neurodegeneration, inflammation and the spread of pathologies through the brain. Here, we conducted a systematic search of the literature and review evidence supporting a role for APOE4 in neurodegeneration and inflammation. While there is no direct evidence yet for APOE4 influencing the spread of pathology, we postulate that this may be found in future based on the literature reviewed here. In conclusion, this review highlights the importance of understanding the role of APOE in multiple important pathological mechanisms in AD.
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Affiliation(s)
- M. Tzioras
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - C. Davies
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - A. Newman
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
| | - R. Jackson
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
- Massachusetts General Hospital and Harvard Medical SchoolCharlestownMAUSA
| | - T. Spires‐Jones
- UK Dementia Research Institute and Centre for Discovery Brain SciencesThe University of EdinburghEdinburghUK
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12
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Muth C, Hartmann A, Sepulveda-Falla D, Glatzel M, Krasemann S. Phagocytosis of Apoptotic Cells Is Specifically Upregulated in ApoE4 Expressing Microglia in vitro. Front Cell Neurosci 2019; 13:181. [PMID: 31130847 PMCID: PMC6509203 DOI: 10.3389/fncel.2019.00181] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/12/2019] [Indexed: 01/08/2023] Open
Abstract
Alzheimer’s disease (AD) is characterized by intracellular tau aggregates and extracellular deposition of amyloid-β (Aβ). The major genetic risk factor to develop AD is the Apolipoprotein E isoform 4 (ApoE4). ApoE4 may directly affect Aβ pathology, yet the exact role of ApoE4 in the progression of AD remains unclear. Although astrocytes are the main source of ApoE in brain tissue, other cell types might contribute to ApoE isotype-dependent effects. While ApoE expression does not play a relevant role in homeostatic microglia, we and others could recently show that ApoE expression is significant upregulated in disease-associated microglia including AD-mouse models and human AD. ApoE has been supposed to have an anti-inflammatory effect, with ApoE4 being less effective than ApoE3. However, ApoE-isotype specific effects on microglia function in disease have not been thoroughly investigated to date. In contrast to this, the role of ApoE2, the third most common major ApoE isoform, in neurodegeneration has not been characterized in detail, but it has been shown to delay the onset of disease in familial AD. To elucidate the differential roles of the three-major human ApoE isoforms on microglia function we each expressed the human ApoE isoforms in murine N9 microglia cells. We could show that ApoE4 specifically influences actin cytoskeleton rearrangement and morphology. In migration assays, ApoE4 significantly promotes cell motility. To quantify phagocytosis by microglia we established an uptake assay based on imaging flow cytometry. Although expression of ApoE4 led to significantly reduced uptake of Aβ in contrast to the other isoforms, we could show that ApoE4 specifically increased phagocytosis of apoptotic neuronal cells. Our findings show that ApoE4 intrinsically affects microglia physiology by upregulating motility and phagocytic behavior in vitro and may therefore specifically contribute to microglia dysregulation in AD.
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Affiliation(s)
- Christiane Muth
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Hartmann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Diego Sepulveda-Falla
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Krasemann
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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13
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Abstract
BACKGROUND The growing body of evidence indicating the heterogeneity of Alzheimer's disease (AD), coupled with disappointing clinical studies directed at a fit-for-all therapy, suggest that the development of a single magic cure suitable for all cases may not be possible. This calls for a shift in paradigm where targeted treatment is developed for specific AD subpopulations that share distinct genetic or pathological properties. Apolipoprotein E4 (apoE4), the most prevalent genetic risk factor of AD, is expressed in more than half of AD patients and is thus an important possible AD therapeutic target. REVIEW This review focuses initially on the pathological effects of apoE4 in AD, as well as on the corresponding cellular and animal models and the suggested cellular and molecular mechanisms which mediate them. The second part of the review focuses on recent apoE4-targeted (from the APOE gene to the apoE protein and its interactors) therapeutic approaches that have been developed in animal models and are ready to be translated to human. Further, the issue of whether the pathological effects of apoE4 are due to loss of protective function or due to gain of toxic function is discussed herein. It is possible that both mechanisms coexist, with certain constituents of the apoE4 molecule and/or its downstream signaling mediating a toxic effect, while others are associated with a loss of protective function. CONCLUSION ApoE4 is a promising AD therapeutic target that remains understudied. Recent studies are now paving the way for effective apoE4-directed AD treatment approaches.
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14
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Fernandez CG, Hamby ME, McReynolds ML, Ray WJ. The Role of APOE4 in Disrupting the Homeostatic Functions of Astrocytes and Microglia in Aging and Alzheimer's Disease. Front Aging Neurosci 2019; 11:14. [PMID: 30804776 PMCID: PMC6378415 DOI: 10.3389/fnagi.2019.00014] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/16/2019] [Indexed: 12/20/2022] Open
Abstract
APOE4 is the greatest genetic risk factor for late-onset Alzheimer’s disease (AD), increasing the risk of developing the disease by 3-fold in the 14% of the population that are carriers. Despite 25 years of research, the exact mechanisms underlying how APOE4 contributes to AD pathogenesis remain incompletely defined. APOE in the brain is primarily expressed by astrocytes and microglia, cell types that are now widely appreciated to play key roles in the pathogenesis of AD; thus, a picture is emerging wherein APOE4 disrupts normal glial cell biology, intersecting with changes that occur during normal aging to ultimately cause neurodegeneration and cognitive dysfunction. This review article will summarize how APOE4 alters specific pathways in astrocytes and microglia in the context of AD and the aging brain. APOE itself, as a secreted lipoprotein without enzymatic activity, may prove challenging to directly target therapeutically in the classical sense. Therefore, a deeper understanding of the underlying pathways responsible for APOE4 toxicity is needed so that more tractable pathways and drug targets can be identified to reduce APOE4-mediated disease risk.
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Affiliation(s)
- Celia G Fernandez
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Mary E Hamby
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Morgan L McReynolds
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - William J Ray
- The Neurodegeneration Consortium, Institute of Applied Cancer Science (IACS), The University of Texas MD Anderson Cancer Center, Houston, TX, United States
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15
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Jairani PS, Aswathy PM, Krishnan D, Menon RN, Verghese J, Mathuranath PS, Gopala S. Apolipoprotein E Polymorphism and Oxidative Stress in Peripheral Blood-Derived Macrophage-Mediated Amyloid-Beta Phagocytosis in Alzheimer's Disease Patients. Cell Mol Neurobiol 2019; 39:355-369. [PMID: 30694418 DOI: 10.1007/s10571-019-00651-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/09/2019] [Indexed: 12/06/2022]
Abstract
Peripheral blood-derived macrophages isolated from Alzheimer's disease (AD) patients have earlier been reported to demonstrate ineffective phagocytosis of amyloid-beta compared to the age-matched control subjects. However, the mechanisms causing unsuccessful phagocytosis remain unclear. Oxidative stress and the presence of ApoEε4 allele has been reported to play a major role in the pathogenesis of AD, but the contribution of oxidative stress and ApoEε4 in macrophage dysfunction leading to ineffective Aβ phagocytosis needs to be analyzed. Aβ phagocytosis assay has been performed using FITC-labeled Aβ and analyzed using flow cytometry and confocal imaging in patient samples and in THP-1 cells. Oxidative stress in patient-derived macrophages was analyzed by assessing the DNA damage using comet assay. ApoE polymorphism was analyzed using sequence-specific PCR and Hixson & Vernier Restriction isotyping protocol. In this study, we have analyzed the patterns of phagocytic inefficiency of macrophages in Indian population with a gradual decline in the phagocytic potential from mild cognitive impairment (MCI) to AD patients. Further, we have shown that the presence of ApoEε4 allele might also have a possible effect on the phagocytosis efficiency of the macrophages. Here, we demonstrate for the first time that oxidative stress could affect the amyloid-beta phagocytic potential of macrophages and hence by alleviating oxidative stress using curcumin, an anti-oxidant could enhance the amyloid-beta phagocytic efficacy of macrophages of patients with AD and MCI, although the responsiveness to curcumin might depends on the presence or absence of APOEε4 allele. Oxidative stress contributes significantly to decreased phagocytosis of Aβ by macrophages. Moreover, the phagocytic inefficiency of macrophages was correlated to the presence of ApoEε4 allele. This study also found that the Aβ-phagocytic potential of macrophage gets significantly enhanced in curcumin-treated patient-derived macrophages.
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Affiliation(s)
- P S Jairani
- Cognition & Behavioral Neurology Section, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, India
| | - P M Aswathy
- Cognition & Behavioral Neurology Section, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, India
| | - Dhanya Krishnan
- Department of Biochemistry, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, 695011, India
| | - Ramsekhar N Menon
- Cognition & Behavioral Neurology Section, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, India
| | - Joe Verghese
- Department of Neurology, Albert Einstein College of Medicine, New York, NY, USA
| | - P S Mathuranath
- Cognition & Behavioral Neurology Section, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, India.,Department of Neurology, National Institute of Mental Health & Neuro Sciences (NIMHANS), Bangalore, India
| | - Srinivas Gopala
- Department of Biochemistry, Sree Chitra Tirunal Institute for Medical Sciences & Technology (SCTIMST), Thiruvananthapuram, Kerala, 695011, India.
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16
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Nnah IC, Wessling-Resnick M. Brain Iron Homeostasis: A Focus on Microglial Iron. Pharmaceuticals (Basel) 2018; 11:ph11040129. [PMID: 30477086 PMCID: PMC6316365 DOI: 10.3390/ph11040129] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/14/2022] Open
Abstract
Iron is an essential trace element required for important brain functions including oxidative metabolism, synaptic plasticity, myelination, and the synthesis of neurotransmitters. Disruptions in brain iron homeostasis underlie many neurodegenerative diseases. Increasing evidence suggests that accumulation of brain iron and chronic neuroinflammation, characterized by microglia activation and secretion of proinflammatory cytokines, are hallmarks of neurodegenerative disorders including Alzheimer’ s disease. While substantial efforts have led to an increased understanding of iron metabolism and the role of microglial cells in neuroinflammation, important questions still remain unanswered. Whether or not increased brain iron augments the inflammatory responses of microglial cells, including the molecular cues that guide such responses, is still unclear. How these brain macrophages accumulate, store, and utilize intracellular iron to carry out their various functions under normal and disease conditions is incompletely understood. Here, we describe the known and emerging mechanisms involved in microglial cell iron transport and metabolism as well as inflammatory responses in the brain, with a focus on AD.
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Affiliation(s)
- Israel C Nnah
- Department of Genetics and Complex Diseases, Harvard TH Chan School of Public Health, Boston, MA 02115, USA.
| | - Marianne Wessling-Resnick
- Department of Genetics and Complex Diseases, Harvard TH Chan School of Public Health, Boston, MA 02115, USA.
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17
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Fan LY, Tzen KY, Chen YF, Chen TF, Lai YM, Yen RF, Huang YY, Shiue CY, Yang SY, Chiu MJ. The Relation Between Brain Amyloid Deposition, Cortical Atrophy, and Plasma Biomarkers in Amnesic Mild Cognitive Impairment and Alzheimer's Disease. Front Aging Neurosci 2018; 10:175. [PMID: 29967578 PMCID: PMC6015901 DOI: 10.3389/fnagi.2018.00175] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/22/2018] [Indexed: 01/25/2023] Open
Abstract
Background: Neuritic plaques and neurofibrillary tangles are the pathological hallmarks of Alzheimer’s disease (AD), while the role of brain amyloid deposition in the clinical manifestation or brain atrophy remains unresolved. We aimed to explore the relation between brain amyloid deposition, cortical thickness, and plasma biomarkers. Methods: We used 11C-Pittsburgh compound B-positron emission tomography to assay brain amyloid deposition, magnetic resonance imaging to estimate cortical thickness, and an immunomagnetic reduction assay to measure plasma biomarkers. We recruited 39 controls, 25 subjects with amnesic mild cognitive impairment (aMCI), and 16 subjects with AD. PiB positivity (PiB+) was defined by the upper limit of the 95% confidence interval of the mean cortical SUVR from six predefined regions (1.0511 in this study). Results: All plasma biomarkers showed significant between-group differences. The plasma Aβ40 level was positively correlated with the mean cortical thickness of both the PiB+ and PiB- subjects. The plasma Aβ40 level of the subjects who were PiB+ was negatively correlated with brain amyloid deposition. In addition, the plasma tau level was negatively correlated with cortical thickness in both the PiB+ and PiB- subjects. Moreover, cortical thickness was negatively correlated with brain amyloid deposition in the PiB+ subjects. In addition, the cut-off point of plasma tau for differentiating between controls and AD was higher in the PiB- group than in the PiB+ group (37.5 versus 25.6 pg/ml, respectively). Lastly, ApoE4 increased the PiB+ rate in the aMCI and control groups. Conclusion: The contributions of brain amyloid deposition to cortical atrophy are spatially distinct. Plasma Aβ40 might be a protective indicator of less brain amyloid deposition and cortical atrophy. It takes more tau pathology to reach the same level of cognitive decline in subjects without brain amyloid deposition, and ApoE4 plays an early role in amyloid pathogenesis.
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Affiliation(s)
- Ling-Yun Fan
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Brain and Mind Sciences, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kai-Yuan Tzen
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Nuclear Medicine, Changhua Christian Hospital, Changhua City, Taiwan.,Molecular Imaging Center, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Fang Chen
- Department of Medical Imaging, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ta-Fu Chen
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Mei Lai
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ruoh-Fang Yen
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Molecular Imaging Center, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Yao Huang
- Molecular Imaging Center, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chyng-Yann Shiue
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Molecular Imaging Center, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,PET Center, Tri-Service General Hospital, Taipei, Taiwan
| | | | - Ming-Jang Chiu
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Brain and Mind Sciences, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Psychology, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
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18
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Forero DA, López-León S, González-Giraldo Y, Dries DR, Pereira-Morales AJ, Jiménez KM, Franco-Restrepo JE. APOE gene and neuropsychiatric disorders and endophenotypes: A comprehensive review. Am J Med Genet B Neuropsychiatr Genet 2018; 177:126-142. [PMID: 27943569 DOI: 10.1002/ajmg.b.32516] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/07/2016] [Indexed: 12/14/2022]
Abstract
The Apolipoprotein E (APOE) gene is one of the main candidates in neuropsychiatric genetics, with hundreds of studies carried out in order to explore the possible role of polymorphisms in the APOE gene in a large number of neurological diseases, psychiatric disorders, and related endophenotypes. In the current article, we provide a comprehensive review of the structural and functional aspects of the APOE gene and its relationship with brain disorders. Evidence from genome-wide association studies and meta-analyses shows that the APOE gene has been significantly associated with several neurodegenerative disorders. Cellular and animal models show growing evidence of the key role of APOE in mechanisms of brain plasticity and behavior. Future analyses of the APOE gene might find a possible role in other neurological diseases and psychiatric disorders and related endophenotypes. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Diego A Forero
- Laboratory of Neuropsychiatric Genetics, Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia.,PhD Program in Health Sciences, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | | | - Yeimy González-Giraldo
- Departamento de Nutrición y Bioquímica, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Daniel R Dries
- Chemistry Department, Juniata College, Huntingdon, Pennsylvania
| | - Angela J Pereira-Morales
- Laboratory of Neuropsychiatric Genetics, Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - Karen M Jiménez
- Laboratory of Neuropsychiatric Genetics, Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - Juan E Franco-Restrepo
- PhD Program in Health Sciences, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
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19
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Efthymiou AG, Goate AM. Late onset Alzheimer's disease genetics implicates microglial pathways in disease risk. Mol Neurodegener 2017; 12:43. [PMID: 28549481 PMCID: PMC5446752 DOI: 10.1186/s13024-017-0184-x] [Citation(s) in RCA: 360] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/17/2017] [Indexed: 12/15/2022] Open
Abstract
Alzheimer's disease (AD) is a highly heritable complex disease with no current effective prevention or treatment. The majority of drugs developed for AD focus on the amyloid cascade hypothesis, which implicates Aß plaques as a causal factor in the disease. However, it is possible that other underexplored disease-associated pathways may be more fruitful targets for drug development. Findings from gene network analyses implicate immune networks as being enriched in AD; many of the genes in these networks fall within genomic regions that contain common and rare variants that are associated with increased risk of developing AD. Of these genes, several (including CR1, SPI1, the MS4As, TREM2, ABCA7, CD33, and INPP5D) are expressed by microglia, the resident immune cells of the brain. We summarize the gene network and genetics findings that implicate that these microglial genes are involved in AD, as well as several studies that have looked at the expression and function of these genes in microglia and in the context of AD. We propose that these genes are contributing to AD in a non-Aß-dependent fashion.
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Affiliation(s)
- Anastasia G. Efthymiou
- Department of Neuroscience, Ronald M. Loeb Center for Alzheimer’s disease, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY 10029 USA
| | - Alison M. Goate
- Department of Neuroscience, Ronald M. Loeb Center for Alzheimer’s disease, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, New York, NY 10029 USA
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20
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Postupna N, Latimer CS, Larson EB, Sherfield E, Paladin J, Shively CA, Jorgensen MJ, Andrews RN, Kaplan JR, Crane PK, Montine KS, Craft S, Keene CD, Montine TJ. Human Striatal Dopaminergic and Regional Serotonergic Synaptic Degeneration with Lewy Body Disease and Inheritance of APOE ε4. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:884-895. [PMID: 28212814 DOI: 10.1016/j.ajpath.2016.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 12/10/2016] [Accepted: 12/20/2016] [Indexed: 01/22/2023]
Abstract
Cognitive impairment in older individuals is a complex trait that in population-based studies most commonly derives from an individually varying mixture of Alzheimer disease, Lewy body disease, and vascular brain injury. We investigated the molecular composition of synaptic particles from three sources: consecutive rapid autopsy brains from the Adult Changes in Thought Study, a population-based cohort; four aged nonhuman primate brains optimally processed for molecular investigation; and targeted replacement transgenic mice homozygous for APOE ε4. Our major goal was to characterize the molecular composition of human synaptic particles in regions of striatum and prefrontal cortex. We performed flow cytometry to measure six markers of synaptic subtypes, as well as amyloid β 42 and paired helical filament tau. Our results showed selective degeneration of dopaminergic terminals throughout the striatum in individuals with Lewy body disease, and serotonergic degeneration in human ventromedial caudate nucleus from individuals with an APOE ε4 allele. Similar results were seen in mouse caudate nucleus homozygous for APOE ε4 via targeted replacement. Together, extension of these clinical, pathologic, and genetic associations from tissue to the synaptic compartment of cerebral cortex and striatum strongly supports our approach for accurately observing the molecular composition of human synapses by flow cytometry.
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Affiliation(s)
- Nadia Postupna
- Department of Pathology, University of Washington, Seattle, Washington
| | - Caitlin S Latimer
- Department of Pathology, University of Washington, Seattle, Washington
| | - Eric B Larson
- Group Health Research Institute, Seattle, Washington
| | - Emily Sherfield
- Department of Pathology, University of Washington, Seattle, Washington
| | - Julie Paladin
- Department of Pathology, University of Washington, Seattle, Washington
| | - Carol A Shively
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Matthew J Jorgensen
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Rachel N Andrews
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jay R Kaplan
- Department of Pathology, Section on Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Paul K Crane
- Department of Medicine, University of Washington, Seattle, Washington
| | | | - Suzanne Craft
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, Washington
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, Washington.
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21
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Serrano-Pozo A, Betensky RA, Frosch MP, Hyman BT. Plaque-Associated Local Toxicity Increases over the Clinical Course of Alzheimer Disease. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 186:375-84. [PMID: 26687817 DOI: 10.1016/j.ajpath.2015.10.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 10/01/2015] [Accepted: 10/07/2015] [Indexed: 11/19/2022]
Abstract
Amyloid (senile) plaques, one of the two pathologic hallmarks of Alzheimer disease (AD), are associated with dystrophic neurites and glial responses, both astrocytic and microglial. Although plaque burden remains relatively stable through the clinical course of AD, whether these features of local plaque toxicity continue to worsen over the course of the disease is unclear. We performed an unbiased plaque-centered quantification of SMI312(+) dystrophic neurites, GFAP(+) reactive astrocytes, and IBA1(+) and CD68(+) activated microglia in randomly selected dense-core (Thioflavin-S(+)) plaques from the temporal neocortex of 40 AD subjects with a symptom duration ranging from 4 to 20 years, and nine nondemented control subjects with dense-core plaques. Dystrophic neurites (Kendall τ = 0.34, P = 0.001), reactive astrocytes (Kendall τ = 0.30, P = 0.003), and CD68(+) (Kendall τ = 0.48, P < 0.0001), but not IBA1 microglia (Kendall τ = 0.045, P = 0.655), exhibited a significant positive correlation with symptom duration. When excluding control subjects, only the positive association between CD68(+) microglia and symptom duration remained significant (Kendall τ = 0.39, P = 0.0003). The presence of the APOEε4 allele did not affect these results. We conclude that plaques exert an increasing toxicity in the surrounding neuropil over the clinical course of AD, thereby potentially contributing to cognitive decline.
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Affiliation(s)
- Alberto Serrano-Pozo
- Massachusetts Alzheimer Disease Research Center, Massachusetts General Hospital, Charlestown, Massachusetts; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts; Department of Neurology, University of Iowa Hospitals & Clinics, Iowa City, Iowa
| | - Rebecca A Betensky
- Massachusetts Alzheimer Disease Research Center, Massachusetts General Hospital, Charlestown, Massachusetts; Biostatistics Center, Massachusetts General Hospital, Boston, Massachusetts; Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Matthew P Frosch
- Massachusetts Alzheimer Disease Research Center, Massachusetts General Hospital, Charlestown, Massachusetts; C. S. Kubik Laboratory for Neuropathology, Massachusetts General Hospital, Boston, Massachusetts
| | - Bradley T Hyman
- Massachusetts Alzheimer Disease Research Center, Massachusetts General Hospital, Charlestown, Massachusetts; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts.
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22
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Mhatre SD, Tsai CA, Rubin AJ, James ML, Andreasson KI. Microglial malfunction: the third rail in the development of Alzheimer's disease. Trends Neurosci 2015; 38:621-636. [PMID: 26442696 PMCID: PMC4670239 DOI: 10.1016/j.tins.2015.08.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Accepted: 08/19/2015] [Indexed: 12/23/2022]
Abstract
Studies of Alzheimer's disease (AD) have predominantly focused on two major pathologies: amyloid-β (Aβ) and hyperphosphorylated tau. These misfolded proteins can accumulate asymptomatically in distinct regions over decades. However, significant Aβ accumulation can be seen in individuals who do not develop dementia, and tau pathology limited to the transentorhinal cortex, which can appear early in adulthood, is usually clinically silent. Thus, an interaction between these pathologies appears to be necessary to initiate and propel disease forward to widespread circuits. Recent multidisciplinary findings strongly suggest that the third factor required for disease progression is an aberrant microglial immune response. This response may initially be beneficial; however, a maladaptive microglial response eventually develops, fueling a feed-forward spread of tau and Aβ pathology.
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Affiliation(s)
- Siddhita D Mhatre
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA; Stanford Neurosciences Institute, Stanford, CA, USA
| | - Connie A Tsai
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA; Stanford Neurosciences Institute, Stanford, CA, USA; Neurosciences Graduate Program, Stanford University, Stanford, CA, USA
| | - Amanda J Rubin
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA; Stanford Neurosciences Institute, Stanford, CA, USA; Neurosciences Graduate Program, Stanford University, Stanford, CA, USA
| | - Michelle L James
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Katrin I Andreasson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA; Stanford Neurosciences Institute, Stanford, CA, USA.
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23
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Abstract
Human cerebrospinal fluid (CSF) contains diverse lipid particles, including lipoproteins that are distinct from their plasma counterparts and contain apolipoprotein (apo) E isoforms, apoJ, and apoAI, and extracellular vesicles, which can be detected by annexin V binding. The aim of this study was to develop a method to quantify CSF particles and evaluate their relationship to aging and neurodegenerative diseases. We used a flow cytometric assay to detect annexin V-, apoE-, apoAI-, apoJ-, and amyloid (A) β42-positive particles in CSF from 131 research volunteers who were neurologically normal or had mild cognitive impairment (MCI), Alzheimer disease (AD) dementia, or Parkinson disease. APOE ε4/ε4 participants had CSF apoE-positive particles that were more frequently larger but at an 88% lower level versus those in APOE ε3/ε3 or APOE ε3/ε4 patients; this finding was reproduced in conditioned medium from mouse primary glial cell cultures with targeted replacement of apoE. Cerebrospinal fluid apoE-positive and β-amyloid (Aβ42)-positive particle concentrations were persistently reduced one-third to one-half in middle and older age subjects; apoAI-positive particle concentration progressively increased approximately 2-fold with age. Both apoAI-positive and annexin V-positive CSF particle levels were reduced one-third to one-half in CSF of MCI and/or AD dementia patients versus age-matched controls. Our approach provides new methods to investigate CNS lipid biology in relation to neurodegeneration and perhaps develop new biomarkers for diagnosis or treatment monitoring.
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24
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Li X, Montine KS, Keene CD, Montine TJ. Different mechanisms of apolipoprotein E isoform-dependent modulation of prostaglandin E2 production and triggering receptor expressed on myeloid cells 2 (TREM2) expression after innate immune activation of microglia. FASEB J 2015; 29:1754-62. [PMID: 25593125 DOI: 10.1096/fj.14-262683] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/15/2014] [Indexed: 01/14/2023]
Abstract
Several lines of evidence support immune response in brain as a mechanism of injury in Alzheimer disease (AD). Moreover, immune activation is heightened in apolipoprotein E (APOE) ε4 carriers; inhibitors of prostaglandin (PG) synthesis show a partially protective effect on AD risk from APOE ε4; and genetic variants in triggering receptor expressed on myeloid cells 2 (TREM2) are a rare but potent risk for AD. We tested the hypothesis that APOE ε4 inheritance modulates both the PGE2 pathway and TREM2 expression using primary murine microglia from targeted replacement (TR) APOE3/3 and APOE4/4 mice. Microglial cyclooxygenase-2, microsomal PGE synthase, and PGE2 expression were increased 2- to 25-fold in both genotypes by TLR activators; however, this induction was significantly (P < 0.01) greater in TR APOE4/4 microglia with TLR3 and TLR4 activators. Microglial TREM2 expression was reduced approximately 85% by all TLR activators; this reduction was approximately one-third greater in microglia from TR APOE4/4 mice. Importantly, both receptor-associated protein and a nuclear factor κ-light-chain-enhancer inhibitor blocked TR APOE4/4-dependent effects on the PGE2 pathway but not on TREM2 expression. These data demonstrate complementary, but mechanistically distinct, regulation of pro- and anti-inflammatory mediators in TR APOE4/4 murine microglia that yields a more proinflammatory state than with TR APOE3/3.
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Affiliation(s)
- Xianwu Li
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Kathleen S Montine
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - C Dirk Keene
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, Washington, USA
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25
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Yu XW, Hu ZL, Ni M, Fang P, Zhang PW, Shu Q, Fan H, Zhou HY, Ni L, Zhu LQ, Chen JG, Wang F. Acid-sensing ion channels promote the inflammation and migration of cultured rat microglia. Glia 2014; 63:483-96. [DOI: 10.1002/glia.22766] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 10/17/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Xiao-Wei Yu
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Zhuang-Li Hu
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
- Key Laboratory of Neurological Diseases (HUST); Ministry of Education of China; Wuhan Hubei 430030 China
- The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province; Wuhan Hubei 430030 China
| | - Ming Ni
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Peng Fang
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Pei-Wei Zhang
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Qing Shu
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Hua Fan
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Hai-Yun Zhou
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
| | - Lan Ni
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
- Key Laboratory of Neurological Diseases (HUST); Ministry of Education of China; Wuhan Hubei 430030 China
- The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province; Wuhan Hubei 430030 China
| | - Ling-Qiang Zhu
- Key Laboratory of Neurological Diseases (HUST); Ministry of Education of China; Wuhan Hubei 430030 China
- The Institute of Brain Research, Huazhong University of Science and Technology; Wuhan 430030 China
| | - Jian-Guo Chen
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
- Key Laboratory of Neurological Diseases (HUST); Ministry of Education of China; Wuhan Hubei 430030 China
- The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province; Wuhan Hubei 430030 China
- The Institute of Brain Research, Huazhong University of Science and Technology; Wuhan 430030 China
| | - Fang Wang
- Department of Pharmacology; School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology; Wuhan Hubei 430030 China
- Key Laboratory of Neurological Diseases (HUST); Ministry of Education of China; Wuhan Hubei 430030 China
- The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province; Wuhan Hubei 430030 China
- The Institute of Brain Research, Huazhong University of Science and Technology; Wuhan 430030 China
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26
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Cudaback E, Yang Y, Montine TJ, Keene CD. APOE genotype-dependent modulation of astrocyte chemokine CCL3 production. Glia 2014; 63:51-65. [PMID: 25092803 DOI: 10.1002/glia.22732] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 07/14/2014] [Indexed: 12/19/2022]
Abstract
Apolipoprotein E (apoE) is well known as a regulator of cholesterol homeostasis, and is increasingly recognized to play a prominent role in the modulation of innate immune response, including cell-to-cell communication and migration. Alzheimer's disease (AD) is a slowly progressive neurodegenerative disorder characterized by neuroinflammation that appears to be an important component of the pathophysiology of the disease. Astrocytes are the majority cell type in brain, exerting significant influence over a range of central nervous system activities, including microglial-mediated neuroinflammatory responses. As the resident innate immune effector cells of the brain, microglia respond to soluble chemical signals released from tissue during injury and disease by mobilizing to lesion sites, clearing toxic molecules, and releasing chemical signals of their own. While microglial-mediated neuroinflammation in the AD brain remains an area of intense investigation, the mechanisms underlying reinforcement and regulation of these aberrant microglial responses by astrocytes are largely unstudied. Moreover, although inheritance of APOE ɛ4 represents the greatest genetic risk factor for sporadic AD, the mechanism by which apoE isoforms differentially influence AD pathophysiology is unknown. Here we show that APOE ɛ4 genotype specifically modulates astrocyte secretion of potent microglial chemotactic agents, including CCL3, thus providing evidence that APOE modulation of central nervous system (CNS) innate immune response is mediated through astrocytes.
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Affiliation(s)
- Eiron Cudaback
- Department of Pathology, University of Washington, Seattle, Washington
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27
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Kanekiyo T, Xu H, Bu G. ApoE and Aβ in Alzheimer's disease: accidental encounters or partners? Neuron 2014; 81:740-54. [PMID: 24559670 DOI: 10.1016/j.neuron.2014.01.045] [Citation(s) in RCA: 423] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2014] [Indexed: 12/26/2022]
Abstract
Among the three human apolipoprotein E (apoE) isoforms, apoE4 increases the risk of Alzheimer's disease (AD). While transporting cholesterol is a primary function, apoE also regulates amyloid-β (Aβ) metabolism, aggregation, and deposition. Although earlier work suggests that different affinities of apoE isoforms to Aβ might account for their effects on Aβ clearance, recent studies indicate that apoE also competes with Aβ for cellular uptake through apoE receptors. Thus, several factors probably determine the variable effects apoE has on Aβ. In this Review, we examine biochemical, structural, and functional studies and propose testable models that address the complex mechanisms underlying apoE-Aβ interaction and how apoE4 may increase AD risk and also serve as a target pathway for therapy.
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Affiliation(s)
- Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen 361005, China
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen 361005, China.
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28
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Shin S, Walz KA, Archambault AS, Sim J, Bollman BP, Koenigsknecht-Talboo J, Cross AH, Holtzman DM, Wu GF. Apolipoprotein E mediation of neuro-inflammation in a murine model of multiple sclerosis. J Neuroimmunol 2014; 271:8-17. [PMID: 24794230 DOI: 10.1016/j.jneuroim.2014.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 03/03/2014] [Accepted: 03/06/2014] [Indexed: 12/12/2022]
Abstract
Apolipoprotein E (ApoE) functions as a ligand in receptor-mediated endocytosis of lipoprotein particles and has been demonstrated to play a role in antigen presentation. To explore the contribution of ApoE during autoimmune central nervous system (CNS) demyelination, we examined the clinical, cellular immune function, and pathologic consequences of experimental autoimmune encephalomyelitis (EAE) induction in ApoE knockout (ApoE(-/-)) mice. We observed reduced clinical severity of EAE in ApoE(-/-) mice in comparison to WT mice that was concomitant with an early reduction of dendritic cells (DCs) followed by a reduction of additional innate cells in the spinal cord at the peak of disease without any differences in axonal damage. While T cell priming was enhanced in ApoE(-/-) mice, reduced severity of EAE was also observed in ApoE(-/-) recipients of encephalitogenic wild type T cells. Expression of ApoE during EAE was elevated within the CNS of wild type mice, particularly by innate cells such as DCs. Overall, ApoE promotes clinical EAE, likely by mediation of inflammation localized within the CNS.
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Affiliation(s)
- Soomin Shin
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Katharine A Walz
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Angela S Archambault
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Julia Sim
- Department of Developmental Biology, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Bryan P Bollman
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Jessica Koenigsknecht-Talboo
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Anne H Cross
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States; Hope Center for Neurological Disorders, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - David M Holtzman
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States; Department of Developmental Biology, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States; Hope Center for Neurological Disorders, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States
| | - Gregory F Wu
- Department of Neurology, Washington University in St. Louis School of Medicine, Box 8111, 660 S. Euclid Avenue, St. Louis, MO 63110, United States; Hope Center for Neurological Disorders, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States; Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, United States.
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29
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Yang Y, Cudaback E, Jorstad NL, Hemingway JF, Hagan CE, Melief EJ, Li X, Yoo T, Khademi SB, Montine KS, Montine TJ, Keene CD. APOE3, but not APOE4, bone marrow transplantation mitigates behavioral and pathological changes in a mouse model of Alzheimer disease. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:905-17. [PMID: 23831297 DOI: 10.1016/j.ajpath.2013.05.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 05/03/2013] [Accepted: 05/24/2013] [Indexed: 12/24/2022]
Abstract
Apolipoprotein E4 (APOE4) genotype is the strongest genetic risk factor for late-onset Alzheimer disease and confers a proinflammatory, neurotoxic phenotype to microglia. Here, we tested the hypothesis that bone marrow cell APOE genotype modulates pathological progression in experimental Alzheimer disease. We performed bone marrow transplants (BMT) from green fluorescent protein-expressing human APOE3/3 or APOE4/4 donor mice into lethally irradiated 5-month-old APPswe/PS1ΔE9 mice. Eight months later, APOE4/4 BMT-recipient APPswe/PS1ΔE9 mice had significantly impaired spatial working memory and increased detergent-soluble and plaque Aβ compared with APOE3/3 BMT-recipient APPswe/PS1ΔE9 mice. BMT-derived microglia engraftment was significantly reduced in APOE4/4 recipients, who also had correspondingly less cerebral apoE. Gene expression analysis in cerebral cortex of APOE3/3 BMT recipients showed reduced expression of tumor necrosis factor-α and macrophage migration inhibitory factor (both neurotoxic cytokines) and elevated immunomodulatory IL-10 expression in APOE3/3 recipients compared with those that received APOE4/4 bone marrow. This was not due to detectable APOE-specific differences in expression of microglial major histocompatibility complex class II, C-C chemokine receptor (CCR) type 1, CCR2, CX3C chemokine receptor 1 (CX3CR1), or C5a anaphylatoxin chemotactic receptor (C5aR). Together, these findings suggest that BMT-derived APOE3-expressing cells are superior to those that express APOE4 in their ability to mitigate the behavioral and neuropathological changes in experimental Alzheimer disease.
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Affiliation(s)
- Yue Yang
- Department of Pathology, University of Washington, Seattle, Washington, USA
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30
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Serrano-Pozo A, Muzikansky A, Gómez-Isla T, Growdon JH, Betensky RA, Frosch MP, Hyman BT. Differential relationships of reactive astrocytes and microglia to fibrillar amyloid deposits in Alzheimer disease. J Neuropathol Exp Neurol 2013; 72:462-71. [PMID: 23656989 PMCID: PMC3661683 DOI: 10.1097/nen.0b013e3182933788] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Although it is clear that astrocytes and microglia cluster around dense-core amyloid plaques in Alzheimer disease (AD), whether they are primarily attracted to amyloid deposits or are just reacting to plaque-associated neuritic damage remains elusive. We postulate that astrocytes and microglia may differentially respond to fibrillar amyloid β. Therefore, we quantified the size distribution of dense-core thioflavin-S (ThioS)-positive plaques in the temporal neocortex of 40 AD patients and the microglial and astrocyte responses in their vicinity (≤50 μm) and performed correlations between both measures. As expected, both astrocytes and microglia were clearly spatially associated with ThioS-positive plaques (p = 0.0001, ≤50 μm vs. >50 μm from their edge), but their relationship to ThioS-positive plaque size differed: larger ThioS-positive plaques were associated with more surrounding activated microglia (p = 0.0026), but this effect was not observed with reactive astrocytes. Microglial response to dense-core plaques seems to be proportional to their size, which we postulate reflects a chemotactic effect of amyloid β. By contrast, plaque-associated astrocytic response does not correlate with plaque size and seems to parallel the behavior of plaque-associated neuritic damage.
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Affiliation(s)
- Alberto Serrano-Pozo
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
| | - Alona Muzikansky
- Massachusetts General Hospital Biostatistics Center, Boston, Massachusetts
| | - Teresa Gómez-Isla
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
| | - John H. Growdon
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
| | - Rebecca A. Betensky
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
- Harvard School of Public Health, Boston, Massachusetts
| | - Matthew P. Frosch
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
- C. S. Kubik Laboratory for Neuropathology. Massachusetts General Hospital, Boston, Massachusetts
| | - Bradley T. Hyman
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Massachusetts Alzheimer Disease Research Center, and Harvard Medical School, Charlestown, Massachusetts
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31
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Serrano-Pozo A, Gómez-Isla T, Growdon JH, Frosch MP, Hyman BT. A phenotypic change but not proliferation underlies glial responses in Alzheimer disease. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 182:2332-44. [PMID: 23602650 DOI: 10.1016/j.ajpath.2013.02.031] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 02/13/2013] [Accepted: 02/21/2013] [Indexed: 12/24/2022]
Abstract
Classical immunohistochemical studies in the Alzheimer disease (AD) brain reveal prominent glial reactions, but whether this pathological feature is due primarily to cell proliferation or to a phenotypic change of existing resting cells remains controversial. We performed double-fluorescence immunohistochemical studies of astrocytes and microglia, followed by unbiased stereology-based quantitation in temporal cortex of 40 AD patients and 32 age-matched nondemented subjects. Glial fibrillary acidic protein (GFAP) and major histocompatibility complex II (MHC2) were used as markers of astrocytic and microglial activation, respectively. Aldehyde dehydrogenase 1 L1 and glutamine synthetase were used as constitutive astrocytic markers, and ionized calcium-binding adaptor molecule 1 (IBA1) as a constitutive microglial marker. As expected, AD patients had higher numbers of GFAP(+) astrocytes and MHC2(+) microglia than the nondemented subjects. However, both groups had similar numbers of total astrocytes and microglia and, in the AD group, these total numbers remained essentially constant over the clinical course of the disease. The GFAP immunoreactivity of astrocytes, but not the MHC2 immunoreactivity of microglia, increased in parallel with the duration of the clinical illness in the AD group. Cortical atrophy contributed to the perception of increased glia density. We conclude that a phenotypic change of existing glial cells, rather than a marked proliferation of glial precursors, accounts for the majority of the glial responses observed in the AD brain.
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Affiliation(s)
- Alberto Serrano-Pozo
- Massachusetts Alzheimer's Disease Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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32
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Corriden R, Insel PA. New insights regarding the regulation of chemotaxis by nucleotides, adenosine, and their receptors. Purinergic Signal 2012; 8:587-98. [PMID: 22528684 PMCID: PMC3360098 DOI: 10.1007/s11302-012-9311-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 01/05/2012] [Indexed: 12/23/2022] Open
Abstract
The directional movement of cells can be regulated by ATP, certain other nucleotides (e.g., ADP, UTP), and adenosine. Such regulation occurs for cells that are "professional phagocytes" (e.g., neutrophils, macrophages, certain lymphocytes, and microglia) and that undergo directional migration and subsequent phagocytosis. Numerous other cell types (e.g., fibroblasts, endothelial cells, neurons, and keratinocytes) also change motility and migration in response to ATP, other nucleotides, and adenosine. In this article, we review how nucleotides and adenosine modulate chemotaxis and motility and highlight the importance of nucleotide- and adenosine-regulated cell migration in several cell types: neutrophils, microglia, endothelial cells, and cancer cells. We also discuss difficulties in conducting experiments and drawing conclusions regarding the ability of nucleotides and adenosine to modulate the migration of professional and non-professional phagocytes.
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Affiliation(s)
- Ross Corriden
- Institute of Cell Signalling, University of Nottingham, Nottingham, UK
| | - Paul A. Insel
- Departments of Pharmacology and Medicine, University of California, San Diego, CA USA
- Department of Pharmacology, University of California San Diego, 9500 Gilman Drive, Mail code 0636, La Jolla, CA 92093 USA
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33
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Cudaback E, Li X, Yang Y, Yoo T, Montine KS, Craft S, Montine TJ, Keene CD. Apolipoprotein C-I is an APOE genotype-dependent suppressor of glial activation. J Neuroinflammation 2012; 9:192. [PMID: 22883744 PMCID: PMC3490924 DOI: 10.1186/1742-2094-9-192] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 07/25/2012] [Indexed: 12/13/2022] Open
Abstract
Background Inheritance of the human ϵ4 allele of the apolipoprotein (apo) E gene (APOE) significantly increases the risk of developing Alzheimer’s disease (AD), in addition to adversely influencing clinical outcomes of other neurologic diseases. While apoE isoforms differentially interact with amyloid β (Aβ), a pleiotropic neurotoxin key to AD etiology, more recent work has focused on immune regulation in AD pathogenesis and on the mechanisms of innate immunomodulatory effects associated with inheritance of different APOE alleles. APOE genotype modulates expression of proximal genes including APOC1, which encodes a small apolipoprotein that is associated with Aβ plaques. Here we tested the hypothesis that APOE-genotype dependent innate immunomodulation may be mediated in part by apoC-I. Methods ApoC-I concentration in cerebrospinal fluid from control subjects of differing APOE genotypes was quantified by ELISA. Real-time PCR and ELISA were used to analyze apoC-I mRNA and protein expression, respectively, in liver, serum, cerebral cortex, and cultured primary astrocytes derived from mice with targeted replacement of murine APOE for human APOE ϵ3 or ϵ4. ApoC-I direct modulation of innate immune activity was investigated in cultured murine primary microglia and astrocytes, as well as human differentiated macrophages, using specific toll-like receptor agonists LPS and PIC as well as Aβ. Results ApoC-I levels varied with APOE genotype in humans and in APOE targeted replacement mice, with ϵ4 carriers showing significantly less apoC-I in both species. ApoC-I potently reduced pro-inflammatory cytokine secretion from primary murine microglia and astrocytes, and human macrophages, stimulated with LPS, PIC, or Aβ. Conclusions ApoC-I is immunosuppressive. Our results illuminate a novel potential mechanism for APOE genotype risk for AD; one in which patients with an ϵ4 allele have decreased expression of apoC-I resulting in increased innate immune activity.
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Affiliation(s)
- Eiron Cudaback
- Department of Pathology, University of Washington, Seattle, WA 98104, USA
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Keene CD, Cudaback E, Li X, Montine KS, Montine TJ. Apolipoprotein E isoforms and regulation of the innate immune response in brain of patients with Alzheimer's disease. Curr Opin Neurobiol 2011; 21:920-8. [PMID: 21907569 DOI: 10.1016/j.conb.2011.08.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 02/08/2023]
Abstract
The largest genetic risk for late-onset Alzheimer's disease (AD) resides at the apolipoprotein E gene (APOE) locus, which has three common alleles (ɛ2, ɛ3, ɛ4) that encode three isoforms (apoE2, apoE3, apoE4). The very strong association of the APOE ɛ4 allele with AD risk and its role in the accumulation of amyloid β in brains of people and animal models solidify the biological relevance of apoE isoforms but do not provide mechanistic insight. The innate immune response is consistently observed in AD and is a likely contributor to neuronal injury and response to injury. Here we review emerging data showing that apoE isoform regulation of multiple facets of the innate immune response in the brain may alter AD not only through amyloid β-dependent mechanisms, but also through other, amyloid β-independent mechanisms.
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Affiliation(s)
- C Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States
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