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Lana D, Ugolini F, Wenk GL, Giovannini MG, Zecchi-Orlandini S, Nosi D. Microglial distribution, branching, and clearance activity in aged rat hippocampus are affected by astrocyte meshwork integrity: evidence of a novel cell-cell interglial interaction. FASEB J 2018; 33:4007-4020. [PMID: 30496700 DOI: 10.1096/fj.201801539r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aging and neurodegenerative diseases share a condition of neuroinflammation entailing the production of endogenous cell debris in the CNS that must be removed by microglia ( i.e., resident macrophages), to restore tissue homeostasis. In this context, extension of microglial cell branches toward cell debris underlies the mechanisms of microglial migration and phagocytosis. Amoeboid morphology and the consequent loss of microglial branch functionality characterizes dysregulated microglia. Microglial migration is assisted by another glial population, the astroglia, which forms a dense meshwork of cytoplasmic projections. Amoeboid microglia and disrupted astrocyte meshwork are consistent traits in aged CNS. In this study, we assessed a possible correlation between microglia and astroglia morphology in rat models of chronic neuroinflammation and aging, by 3-dimensional confocal analysis implemented with particle analysis. Our findings suggest that a microglia-astroglia interaction occurs in rat hippocampus via cell-cell contacts, mediating microglial cell branching in the presence of inflammation. In aged rats, the impairment of such an interaction correlates with altered distribution, morphology, and inefficient clearance by microglia. These data support the idea that generally accepted functional boundaries between microglia and astrocytes should be re-evaluated to better understand how their functions overlap and interact.-Lana, D., Ugolini, F., Wenk, G. L., Giovannini, M. G., Zecchi-Orlandini, S., Nosi, D. Microglial distribution, branching, and clearance activity in aged rat hippocampus are affected by astrocyte meshwork integrity: evidence of a novel cell-cell interglial interaction.
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Affiliation(s)
- Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Filippo Ugolini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Gary L Wenk
- Department of Psychology, The Ohio State University, Columbus, Ohio, USA
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | | | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
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102
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Ugolini F, Lana D, Nardiello P, Nosi D, Pantano D, Casamenti F, Giovannini MG. Different Patterns of Neurodegeneration and Glia Activation in CA1 and CA3 Hippocampal Regions of TgCRND8 Mice. Front Aging Neurosci 2018; 10:372. [PMID: 30483118 PMCID: PMC6243135 DOI: 10.3389/fnagi.2018.00372] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/26/2018] [Indexed: 01/24/2023] Open
Abstract
We investigated the different patterns of neurodegeneration and glia activation in CA1 and CA3 hippocampal areas of TgCRND8 mice. The main feature of this transgenic model is the rapid development of the amyloid pathology, which starts already at 3 months of age. We performed immunohistochemical analyses to compare the different sensibility of the two hippocampal regions to neurodegeneration. We performed qualitative and quantitative evaluations by fluorescence immunohistochemistry with double or triple staining, followed by confocal microscopy and digital image analysis in stratum pyramidale (SP) and stratum radiatum (SR) of CA1 and CA3, separately. We evaluated time-dependent Aβ plaques deposition, expression of inflammatory markers, as well as quantitative and morphological alterations of neurons and glia in transgenic mice at 3 (Tg 3M) and 6 (Tg 6M) months of age, compared to WT mice. In CA1 SR of Tg 6M mice, we found significantly more Medium and Large plaques than in CA3. The pattern of neurodegeneration and astrocytes activation was different in the two areas, indicating higher sensitivity of CA1. In the CA1 SP of Tg 6M mice, we found signs of reactive astrogliosis, such as increase of astrocytes density in SP, increase of GFAP expression in SR, and elongation of astrocytes branches. We found also common patterns of glia activation and neurodegenerative processes in CA1 and CA3 of Tg 6M mice: significant increase of total and reactive microglia density in SP and SR, increased expression of TNFα, of iNOS, and IL1β in astrocytes and increased density of neurons-astrocytes-microglia triads. In CA1 SP, we found decrease of volume and number of pyramidal neurons, paralleled by increase of apoptosis, and, consequently, shrinkage of CA1 SP. These data demonstrate that in TgCRND8 mice, the responses of neurons and glia to neurodegenerative patterns induced by Aβ plaques deposition is not uniform in the two hippocampal areas, and in CA1 pyramidal neurons, the higher sensitivity may be related to the different plaque distribution in this area. All these modifications may be at the basis of memory loss, the peculiar symptom of AD, which was demonstrated in this transgenic mouse model of Aβ deposition, even at early stages.
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Affiliation(s)
- Filippo Ugolini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Pamela Nardiello
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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103
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Reiss AB, Arain HA, Stecker MM, Siegart NM, Kasselman LJ. Amyloid toxicity in Alzheimer's disease. Rev Neurosci 2018; 29:613-627. [PMID: 29447116 DOI: 10.1515/revneuro-2017-0063] [Citation(s) in RCA: 285] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 12/17/2017] [Indexed: 12/19/2022]
Abstract
A major feature of Alzheimer's disease (AD) pathology is the plaque composed of aggregated amyloid-β (Aβ) peptide. Although these plaques may have harmful properties, there is much evidence to implicate soluble oligomeric Aβ as the primary noxious form. Aβ oligomers can be generated both extracellularly and intracellularly. Aβ is toxic to neurons in a myriad of ways. It can cause pore formation resulting in the leakage of ions, disruption of cellular calcium balance, and loss of membrane potential. It can promote apoptosis, cause synaptic loss, and disrupt the cytoskeleton. Current treatments for AD are limited and palliative. Much research and effort is being devoted to reducing Aβ production as an approach to slowing or preventing the development of AD. Aβ formation results from the amyloidogenic cleavage of human amyloid precursor protein (APP). Reconfiguring this process to disfavor amyloid generation might be possible through the reduction of APP or inhibition of enzymes that convert the precursor protein to amyloid.
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Affiliation(s)
- Allison B Reiss
- Winthrop Research Institute, NYU Winthrop Hospital, 101 Mineola Boulevard, Mineola, NY 11501, USA
| | - Hirra A Arain
- Winthrop Research Institute, NYU Winthrop Hospital, 101 Mineola Boulevard, Mineola, NY 11501, USA
| | - Mark M Stecker
- Winthrop Research Institute, NYU Winthrop Hospital, 101 Mineola Boulevard, Mineola, NY 11501, USA
| | - Nicolle M Siegart
- Winthrop Research Institute, NYU Winthrop Hospital, 101 Mineola Boulevard, Mineola, NY 11501, USA
| | - Lora J Kasselman
- Winthrop Research Institute, NYU Winthrop Hospital, 101 Mineola Boulevard, Mineola, NY 11501, USA
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104
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Shen Z, Bao X, Wang R. Clinical PET Imaging of Microglial Activation: Implications for Microglial Therapeutics in Alzheimer's Disease. Front Aging Neurosci 2018; 10:314. [PMID: 30349474 PMCID: PMC6186779 DOI: 10.3389/fnagi.2018.00314] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 09/19/2018] [Indexed: 12/19/2022] Open
Abstract
In addition to extracellular β-amyloid plaques and intracellular neurofibrillary tangles, neuroinflammation has been identified as a key pathological characteristic of Alzheimer's disease (AD). Once activated, neuroinflammatory cells called microglia acquire different activation phenotypes. At the early stage of AD, activated microglia are mainly dominated by the neuroprotective and anti-inflammatory M2 phenotype. Conversely, in the later stage of AD, the excessive activation of microglia is considered detrimental and pro-inflammatory, turning into the M1 phenotype. Therapeutic strategies targeting the modulation of microglia may regulate their specific phenotype. Fortunately, with the rapid development of in vivo imaging methodologies, visualization of microglial activation has been well-explored. In this review, we summarize the critical role of activated microglia during the pathogenesis of AD and current studies concerning imaging of microglial activation in AD patients. We explore the possibilities for identifying activated microglial phenotypes with imaging techniques and highlight promising therapies that regulate the microglial phenotype in AD mice.
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Affiliation(s)
- Zhiwei Shen
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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105
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Cao L, Cao X, Zhou Y, Nagpure BV, Wu ZY, Hu LF, Yang Y, Sethi G, Moore PK, Bian JS. Hydrogen sulfide inhibits ATP-induced neuroinflammation and Aβ 1-42 synthesis by suppressing the activation of STAT3 and cathepsin S. Brain Behav Immun 2018; 73:603-614. [PMID: 29981830 DOI: 10.1016/j.bbi.2018.07.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/24/2018] [Accepted: 07/04/2018] [Indexed: 02/02/2023] Open
Abstract
Neuroinflammation and excessive β-amyloid1-42 (Aβ1-42) generation contribute to the pathogenesis of Alzheimer's disease (AD). Emerging evidence has demonstrated that hydrogen sulfide (H2S), an endogenous gasotransmitter, produces therapeutic effects in AD; however, the underlying mechanisms remain largely elusive. In the present study, we investigated the effects of H2S on exogenous ATP-induced inflammation and Aβ1-42 production in both BV-2 and primary cultured microglial cells and analyzed the potential mechanism(s) mediating these effects. Our results showed that NaHS, an H2S donor, inhibited exogenous ATP-stimulated inflammatory responses as manifested by the reduction of pro-inflammatory cytokines, ROS and activation of nuclear factor-κB (NF-κB) pathway. Furthermore, NaHS also suppressed the enhanced production of Aβ1-42 induced by exogenous ATP, which is probably due to its inhibitory effect on exogenous ATP-boosted expression of amyloid precursor protein (APP) and activation of β- and γ-secretase enzymes. Thereafter, we found that exogenous ATP-induced inflammation and Aβ1-42 production requires the activation of signal transducer and activator of transcription 3 (STAT3) and cathepsin S (Cat S) as inhibition of the activity of either proteins attenuated the effect of exogenous ATP. Intriguingly, NaHS suppressed exogenous ATP-induced phosphorylation of STAT3 and the activation of Cat S. In addition, we observed that NaHS led to the persulfidation of Cat S at cysteine-25. Importantly, mutation of cysteine-25 into serine attenuated the activity of Cat S stimulated by exogenous ATP and subsequent inflammation and Aβ1-42 production, indicating its involvement in H2S-mediated effect. Taken together, our data provide a novel understanding of H2S-mediated effect on neuroinflammation and Aβ1-42 production by suppressing the activation of STAT3 and Cat S.
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Affiliation(s)
- Lei Cao
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Xu Cao
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Yebo Zhou
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Bhushan Vijay Nagpure
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Zhi-Yuan Wu
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Life Science Institute, National University of Singapore, Singapore
| | - Li Fang Hu
- Institute of Neuroscience, Soochow University, Suzhou 215123, China
| | - Yong Yang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Disease, Center for New Drug Safety Evaluation and Research, China Pharmaceutical University, Nanjing, China
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Philp K Moore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore; Life Science Institute, National University of Singapore, Singapore
| | - Jin-Song Bian
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
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106
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Kiyota T, Machhi J, Lu Y, Dyavarshetty B, Nemati M, Yokoyama I, Mosley RL, Gendelman HE. Granulocyte-macrophage colony-stimulating factor neuroprotective activities in Alzheimer's disease mice. J Neuroimmunol 2018; 319:80-92. [PMID: 29573847 PMCID: PMC5916331 DOI: 10.1016/j.jneuroim.2018.03.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/27/2018] [Accepted: 03/15/2018] [Indexed: 12/11/2022]
Abstract
We investigated the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on behavioral and pathological outcomes in Alzheimer's disease (AD) and non-transgenic mice. GM-CSF treatment in AD mice reduced brain amyloidosis, increased plasma Aβ, and rescued cognitive impairment with increased hippocampal expression of calbindin and synaptophysin and increased levels of doublecortin-positive cells in the dentate gyrus. These data extend GM-CSF pleiotropic neuroprotection mechanisms in AD and include regulatory T cell-mediated immunomodulation of microglial function, Aβ clearance, maintenance of synaptic integrity, and induction of neurogenesis. Together these data support further development of GM-CSF as a neuroprotective agent for AD.
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Affiliation(s)
- Tomomi Kiyota
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jatin Machhi
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Yaman Lu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Bhagyalaxmi Dyavarshetty
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Maryam Nemati
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Izumi Yokoyama
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - R L Mosley
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Howard E Gendelman
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
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107
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Chronically raised C-reactive protein is inversely associated with cortical β-amyloid in older adults with subjective memory complaints. Exp Gerontol 2018; 108:226-230. [PMID: 29704641 DOI: 10.1016/j.exger.2018.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/15/2018] [Accepted: 04/18/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND Inflammation promotes amyloidogenesis in animals and markers of inflammation are associated with β-amyloid (Aβ) in humans. Hence, we sought to examine the cross-sectional associations between chronically elevated plasma C reactive protein (CRP) and cortical Aβ in 259 non-demented elderly individuals reporting subjective memory complaints from the Multidomain Alzheimer Preventive Trial (MAPT). METHODS Cortical-to-cerebellar standard uptake value ratios were obtained using [18F] florbetapir positron emission tomography (PET). CRP was measured in plasma using immunoturbidity. Chronically raised CRP was defined as having 2 consecutively high CRP readings (>3 mg/l ≤ 10 mg/l) between study baseline and the 1 year visit (visits were performed at baseline, 6 months, 1 year and then annually). Associations were explored using adjusted multiple linear regression. RESULTS Chronically raised CRP was found to be inversely associated with cortical Aβ (B-coefficient: -0.054, SE: 0.026, p = 0.040) and this association seemed to be specific to apolipoprotein E (Apo E) ε4 carriers (B-coefficient: -0.130, SE: 0.058, p = 0.027). CRP as an isolated reading measured closest to PET scan was also inversely associated with cortical Aβ when CRP was treated as a dichotomized variable (high CRP > 3 mg/l ≤ 10 mg/l, B-coefficient: -0.048, SE: 0.023, p = 0.043). CONCLUSIONS Our preliminary findings suggest that inflammation might be beneficial in the early stages of Alzheimer's disease as the immune systems attempts to combat Aβ pathology particularly in ApoE ε4 carriers. Investigating the temporal relationships between cerebral Aβ and a panel of inflammatory markers would provide further evidence as to whether chronic inflammation might modulate amyloidogenesis in vivo.
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108
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Scavenger Receptor-A deficiency impairs immune response of microglia and astrocytes potentiating Alzheimer's disease pathophysiology. Brain Behav Immun 2018; 69:336-350. [PMID: 29246456 DOI: 10.1016/j.bbi.2017.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/04/2017] [Accepted: 12/11/2017] [Indexed: 12/25/2022] Open
Abstract
Late onset Alzheimer disease's (LOAD) main risk factor is aging. Although it is not well known which age-related factors are involved in its development, evidence points out to the involvement of an impaired amyloid-β (Aβ) clearance in the aged brain among possible causes. Glial cells are the main scavengers of the brain, where Scavenger Receptor class A (SR-A) emerges as a relevant player in AD because of its participation in Aβ uptake and in the modulation of glial cell inflammatory response. Here, we show that SR-A expression is reduced in the hippocampus of aged animals and APP/PS1 mice. Given that Aβ deposition increases in the aging brain, we generated a triple transgenic mouse, which accumulates Aβ and is knockout for SR-A (APP/PS1/SR-A-/-) to evaluate Aβ accumulation and the inflammatory outcome of SR-A depletion in the aged brain. The lifespan of APP/PS1/SR-A-/- mice was greatly reduced, accompanied by a 3-fold increase in plasmatic pro-inflammatory cytokines, and reduced performance in a working memory behavioral assessment. Microglia and astrocytes lacking SR-A displayed impaired oxidative response and nitric oxide production, produced up to 7-fold more pro-inflammatory cytokines and showed a 12-fold reduction in anti-inflammatory cytokines release, with conspicuous changes in lipopolysaccharide-induced glial activation. Isolated microglia from young and adult mice lacking SR-A showed a 50% reduction in phagocytic activity. Our results indicate that reduced expression of SR-A can deregulate glial inflammatory response and potentiate Aβ accumulation, two mechanisms that could contribute to AD progression.
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109
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Hu X, Das B, Hou H, He W, Yan R. BACE1 deletion in the adult mouse reverses preformed amyloid deposition and improves cognitive functions. J Exp Med 2018; 215:927-940. [PMID: 29444819 PMCID: PMC5839766 DOI: 10.1084/jem.20171831] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/16/2017] [Accepted: 01/04/2018] [Indexed: 12/21/2022] Open
Abstract
This study uses mouse models to answer how BACE1 inhibitory drugs will be beneficial to Alzheimer’s patients. Hu et al. find that sequentially increased deletion of BACE1 in one adult Alzheimer’s mouse model reverses preexisting amyloid plaques and mitigates synaptic failures. BACE1 initiates the generation of the β-amyloid peptide, which likely causes Alzheimer’s disease (AD) when accumulated abnormally. BACE1 inhibitory drugs are currently being developed to treat AD patients. To mimic BACE1 inhibition in adults, we generated BACE1 conditional knockout (BACE1fl/fl) mice and bred BACE1fl/fl mice with ubiquitin-CreER mice to induce deletion of BACE1 after passing early developmental stages. Strikingly, sequential and increased deletion of BACE1 in an adult AD mouse model (5xFAD) was capable of completely reversing amyloid deposition. This reversal in amyloid deposition also resulted in significant improvement in gliosis and neuritic dystrophy. Moreover, synaptic functions, as determined by long-term potentiation and contextual fear conditioning experiments, were significantly improved, correlating with the reversal of amyloid plaques. Our results demonstrate that sustained and increasing BACE1 inhibition in adults can reverse amyloid deposition in an AD mouse model, and this observation will help to provide guidance for the proper use of BACE1 inhibitors in human patients.
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Affiliation(s)
- Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Brati Das
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Hailong Hou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
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110
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Hoeijmakers L, Meerhoff GF, de Vries JW, Ruigrok SR, van Dam AM, van Leuven F, Korosi A, Lucassen PJ. The age-related slow increase in amyloid pathology in APP.V717I mice activates microglia, but does not alter hippocampal neurogenesis. Neurobiol Aging 2018; 61:112-123. [DOI: 10.1016/j.neurobiolaging.2017.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 01/09/2023]
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111
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Kaczmarczyk R, Tejera D, Simon BJ, Heneka MT. Microglia modulation through external vagus nerve stimulation in a murine model of Alzheimer's disease. J Neurochem 2017; 146:76-85. [PMID: 29266221 DOI: 10.1111/jnc.14284] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 11/24/2017] [Accepted: 12/04/2017] [Indexed: 01/04/2023]
Abstract
Chronically activated microglia contribute to the development of neurodegenerative diseases such as Alzheimer's disease (AD) by the release of pro-inflammatory mediators that compromise neuronal function and structure. Modulating microglia functions could be instrumental to interfere with disease pathogenesis. Previous studies have shown anti-inflammatory effects of acetylcholine (ACh) or norepinephrine (NE), which mainly activates the β-receptors on microglial cells. Non-invasive vagus nerve stimulation (nVNS) is used in treatment of drug-resistant depression, which is a risk factor for developing AD. The vagus nerve projects to the brainstem's locus coeruleus from which noradrenergic fibers reach to the Nucleus Basalis of Meynert (NBM) and widely throughout the brain. Pilot studies showed first signs of cognitive-enhancing effects of nVNS in AD patients. In this study, the effects of nVNS on mouse microglia cell morphology were analyzed over a period of 280 min by 2-photon laser scanning in vivo microscopy. Total branch length, average branch order and number of branches, which are commonly used indicators for the microglial activation state were determined and compared between young and old wild-type and amyloid precursor protein/presenilin-1 (APP/PS1) transgenic mice. Overall, these experiments show strong morphological changes in microglia, from a neurodestructive to a neuroprotective phenotype, following a brief nVNS in aged animals, especially in APP/PS1 animals, whereas microglia from young animals were morphologically unaffected.
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Affiliation(s)
- Robert Kaczmarczyk
- Department of Neurodegenerative Disease and Gerontopsychiatry, University of Bonn, Bonn, Germany
| | - Dario Tejera
- Department of Neurodegenerative Disease and Gerontopsychiatry, University of Bonn, Bonn, Germany
| | | | - Michael T Heneka
- Department of Neurodegenerative Disease and Gerontopsychiatry, University of Bonn, Bonn, Germany
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112
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Yanguas-Casás N, Crespo-Castrillo A, de Ceballos ML, Chowen JA, Azcoitia I, Arevalo MA, Garcia-Segura LM. Sex differences in the phagocytic and migratory activity of microglia and their impairment by palmitic acid. Glia 2017; 66:522-537. [PMID: 29139169 DOI: 10.1002/glia.23263] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/25/2017] [Accepted: 10/30/2017] [Indexed: 12/11/2022]
Abstract
Sex differences in the incidence, clinical manifestation, disease course, and prognosis of neurological diseases, such as autism spectrum disorders or Alzheimer's disease, have been reported. Obesity has been postulated as a risk factor for cognitive decline and Alzheimer's disease and, during pregnancy, increases the risk of autism spectrum disorders in the offspring. Obesity is associated with increased serum and brain levels of free fatty acids, such as palmitic acid, which activate microglial cells triggering a potent inflammatory cascade. In this study, we have determined the effect of palmitic acid in the inflammatory profile, motility, and phagocytosis of primary male and female microglia, both in basal conditions and in the presence of a pro-inflammatory stimulus (interferon-γ). Male microglia in vitro showed higher migration than female microglia under basal and stimulated conditions. In contrast, female microglia had higher basal and stimulated phagocytic activity than male microglia. Palmitic acid did not affect basal migration or phagocytosis, but abolished the migration and phagocytic activity of male and female microglia in response to interferon-γ. These findings extend previous observations of sex differences in microglia and suggest that palmitic acid impairs the protective responses of these cells.
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Affiliation(s)
| | | | | | - Julie A Chowen
- Department of Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación la Princesa, Madrid, 28009, Spain.,CIBER de Investigación Biomédica en Red: Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Iñigo Azcoitia
- Department of Cell Biology, Faculty of Biology, Universidad Complutense, Madrid, 28040, Spain.,CIBER de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Maria Angeles Arevalo
- Instituto Cajal, CSIC, Madrid, 28002, Spain.,CIBER de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Luis M Garcia-Segura
- Instituto Cajal, CSIC, Madrid, 28002, Spain.,CIBER de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
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113
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Walker DG, Tang TM, Lue LF. Studies on Colony Stimulating Factor Receptor-1 and Ligands Colony Stimulating Factor-1 and Interleukin-34 in Alzheimer's Disease Brains and Human Microglia. Front Aging Neurosci 2017; 9:244. [PMID: 28848420 PMCID: PMC5552759 DOI: 10.3389/fnagi.2017.00244] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/12/2017] [Indexed: 01/08/2023] Open
Abstract
Microglia are dependent on signaling through the colony stimulating factor-1 receptor (CSF-1R/CD115) for growth and survival. Activation of CSF-1R can lead to cell division, while blocking CSF-1R can lead to rapid microglia cell death. CSF-1R has two ligands, the growth factors colony stimulating factor-1 (CSF-1) and the more recently identified interleukin-34 (IL-34). Studies of IL-34 activation of rodent microglia and human macrophages have suggested it has different properties to CSF-1, resulting in an anti-inflammatory reparative phenotype. The goal of this study was to identify if the responses of human postmortem brain microglia to IL-34 differed from their responses to CSF-1 with the aim of identifying different phenotypes of microglia as a result of their responses. To approach this question, we also sought to identify differences between IL-34, CSF-1, and CSF-1R expression in human brain samples to establish whether there was an imbalance in Alzheimer's disease (AD). Using human brain samples [inferior temporal gyrus (ITG) and middle temporal gyrus (MTG)] from distinct cohorts of AD, control and high pathology, or mild cognitive impairment cases, we showed that there was increased expression of CSF-1R and CSF-1 mRNAs in both series of AD cases, and reduced expression of IL-34 mRNA in AD ITG samples. There was no change in expression of these genes in RNA from cerebellum of AD, Parkinson's disease (PD), or control cases. The results suggested an imbalance in CSF-1R signaling in AD. Using RNA sequencing to compare gene expression responses of CSF-1 and IL-34 stimulated human microglia, a profile of responses to CSF-1 and IL-34 was identified. Contrary to earlier work with rodent microglia, IL-34 induced primarily a classical activation response similar to that of CSF-1. It was not possible to identify any genes expressed significantly different by IL-34-stimulated microglia compared to CSF-1-stimulated microglia, but both cytokines did induce certain alternative activation-associated genes. These profiles also showed that a number of genes associated with lysosomal function and Aβ removal were downregulated by IL-34 and CSF-1 stimulation. Compared to earlier results our data indicate that CSF-1R stimulation by IL-34 or CSF-1 produced similar types of responses by elderly postmortem brain-derived microglia.
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Affiliation(s)
- Douglas G Walker
- Neurodegenerative Disease Research Center, Biodesign Institute, Arizona State UniversityTempe, AZ, United States.,Laboratory of Neuroinflammation, Banner Sun Health Research Institute, Sun CityArizona, AZ, United States
| | - Tiffany M Tang
- Neurodegenerative Disease Research Center, Biodesign Institute, Arizona State UniversityTempe, AZ, United States
| | - Lih-Fen Lue
- Neurodegenerative Disease Research Center, Biodesign Institute, Arizona State UniversityTempe, AZ, United States.,Laboratory of Neuroinflammation, Banner Sun Health Research Institute, Sun CityArizona, AZ, United States
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114
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Lund H, Pieber M, Harris RA. Lessons Learned about Neurodegeneration from Microglia and Monocyte Depletion Studies. Front Aging Neurosci 2017; 9:234. [PMID: 28804456 PMCID: PMC5532389 DOI: 10.3389/fnagi.2017.00234] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/05/2017] [Indexed: 12/20/2022] Open
Abstract
While bone marrow-derived Ly6Chi monocytes can infiltrate the central nervous system (CNS) they are developmentally and functionally distinct from resident microglia. Our understanding of the relative importance of these two populations in the distinct processes of pathogenesis and resolution of inflammation during neurodegenerative disorders was limited by a lack of tools to specifically manipulate each cell type. During recent years, the development of experimental cell-specific depletion models has enabled this issue to be addressed. Herein we compare and contrast the different depletion approaches that have been used, focusing on the respective functionalities of microglia and monocyte-derived macrophages in a range of neurodegenerative disease states, and discuss their prospects for immunotherapy.
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Affiliation(s)
- Harald Lund
- Department of Clinical Neuroscience, Karolinska Institutet, Centre for Molecular Medicine, Karolinska Hospital at SolnaSolna, Sweden
| | - Melanie Pieber
- Department of Clinical Neuroscience, Karolinska Institutet, Centre for Molecular Medicine, Karolinska Hospital at SolnaSolna, Sweden
| | - Robert A Harris
- Department of Clinical Neuroscience, Karolinska Institutet, Centre for Molecular Medicine, Karolinska Hospital at SolnaSolna, Sweden
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115
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Shen Z, Li X, Bao X, Wang R. Microglia-targeted stem cell therapies for Alzheimer disease: A preclinical data review. J Neurosci Res 2017. [PMID: 28643422 DOI: 10.1002/jnr.24066] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Alzheimer disease (AD) is a severe, life-threatening illness characterized by gradual memory loss. The classic histological features of AD include extracellular formation of β-amyloid plaques (Aβ), intracellular neurofibrillary tangles (NFT), and synaptic loss. Recently, accumulated evidence has confirmed the critical role of microglia in the development and exacerbation of AD. When Aβ forms deposits, microglia quickly respond to restore brain physiology by activating a series of repair mechanisms. However, prolonged microglial activation is considered detrimental and may aggravate AD progression. To date, there are no curative therapies for AD. The advent of stem cell transplantation offers novel strategies to treat AD in animal models. Furthermore, studies have reported that transplanted stem cells might ameliorate AD symptoms by regulating microglial functions, from detrimental to protective. This review focuses on the crucial functions of microglia in AD and examines the reactions of microglia to transplanted stem cells.
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Affiliation(s)
- Zhiwei Shen
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xueyuan Li
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xinjie Bao
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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116
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Spittau B. Aging Microglia-Phenotypes, Functions and Implications for Age-Related Neurodegenerative Diseases. Front Aging Neurosci 2017; 9:194. [PMID: 28659790 PMCID: PMC5469878 DOI: 10.3389/fnagi.2017.00194] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/30/2017] [Indexed: 12/23/2022] Open
Abstract
Aging of the central nervous system (CNS) is one of the major risk factors for the development of neurodegenerative pathologies such as Parkinson’s disease (PD) and Alzheimer’s disease (AD). The molecular mechanisms underlying the onset of AD and especially PD are not well understood. However, neuroinflammatory responses mediated by microglia as the resident immune cells of the CNS have been reported for both diseases. The unique nature and developmental origin of microglia causing microglial self-renewal and telomere shortening led to the hypothesis that these CNS-specific innate immune cells become senescent. Age-dependent and senescence-driven impairments of microglia functions and responses have been suggested to play essential roles during onset and progression of neurodegenerative diseases. This review article summarizes the current knowledge of microglia phenotypes and functions in the aging CNS and further discusses the implications of these age-dependent microglia changes for the development and progression of AD and PD as the most common neurodegenerative diseases.
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Affiliation(s)
- Björn Spittau
- Department of Molecular Embryology, Faculty of Medicine, Institute for Anatomy and Cell Biology, University of FreiburgFreiburg, Germany.,Institute of Anatomy, University of RostockRostock, Germany
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117
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Wu J, Hocevar M, Foss JF, Bie B, Naguib M. Activation of CB 2 receptor system restores cognitive capacity and hippocampal Sox2 expression in a transgenic mouse model of Alzheimer's disease. Eur J Pharmacol 2017; 811:12-20. [PMID: 28551012 DOI: 10.1016/j.ejphar.2017.05.044] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/17/2017] [Accepted: 05/24/2017] [Indexed: 01/21/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuroinflammation, extensive deposits of amyloid-β aggregates, and loss of memory and cognitive abilities. The brains of patients with AD show increased expression of cannabinoid receptor type 2 (CB2) receptors and glial markers. CB2 receptors act as a negative feedback regulator; when activated by a CB2 agonist, they can help limit the extent of the neuroinflammatory response and the subsequent development of neuronal damage in the central nervous system. In a double transgenic APP/PS1 mice model of AD, we evaluated the effect of MDA7, a CB2 agonist, on several neuropathological conditions of AD including amyloid deposition, inflammatory reaction, Sox2 (sex-determining region Y-box 2) expression, and spatial memory. Activation of microglia CB2 receptors by MDA7 suppressed neuroinflammation, demonstrated by decreased immunosignal of Iba1 in the hippocampal CA1 and dentate gyrus (DG) areas, promoted clearance of amyloid plaques in the DG area, restored Sox2 expression, and promoted recovery of the neuronal synaptic plasticity in hippocampal CA1. In addition, treatment with MDA7 improved the behavioral performance in the Morris water maze in APP/PS1mice. Collectively, these findings suggest that MDA7 has a potential therapeutic effect in the setting of AD.
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Affiliation(s)
- Jiang Wu
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave. - NE6-306, Cleveland, OH 44195, USA
| | - Mark Hocevar
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave. - NE6-306, Cleveland, OH 44195, USA; Medical student, Brown University, Providence, RI 02912, USA
| | - Joseph F Foss
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave. - NE6-306, Cleveland, OH 44195, USA
| | - Bihua Bie
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave. - NE6-306, Cleveland, OH 44195, USA
| | - Mohamed Naguib
- Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Ave. - NE6-306, Cleveland, OH 44195, USA.
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118
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Mendiola AS, Cardona AE. The IL-1β phenomena in neuroinflammatory diseases. J Neural Transm (Vienna) 2017; 125:781-795. [PMID: 28534174 DOI: 10.1007/s00702-017-1732-9] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 05/04/2017] [Indexed: 02/06/2023]
Abstract
It is becoming increasingly clear that neuroinflammation has a causal role in the pathogenesis of central nervous system (CNS)-related diseases, and therefore therapeutic strategies targeting the regulation or availability of inflammatory mediators can be used to prevent or mitigate pathology. Interestingly, the proinflammatory cytokine, interleukin-1 beta (IL-1β), has been implicated in perpetuating immune responses and contributing to disease severity in a variety of CNS diseases ranging from multiple sclerosis, neurodegenerative diseases, traumatic brain injury, and diabetic retinopathy. Moreover, pharmacological blockade of IL-1 signaling has shown to be beneficial in some autoimmune and autoinflammatory diseases, making IL-1β a promising therapeutic target in neuroinflammatory conditions. This review highlights recent advances of our understanding on the multifaceted roles of IL-1β in neuroinflammatory diseases.
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Affiliation(s)
- Andrew S Mendiola
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Astrid E Cardona
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA.
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119
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Mazaheri F, Snaidero N, Kleinberger G, Madore C, Daria A, Werner G, Krasemann S, Capell A, Trümbach D, Wurst W, Brunner B, Bultmann S, Tahirovic S, Kerschensteiner M, Misgeld T, Butovsky O, Haass C. TREM2 deficiency impairs chemotaxis and microglial responses to neuronal injury. EMBO Rep 2017; 18:1186-1198. [PMID: 28483841 DOI: 10.15252/embr.201743922] [Citation(s) in RCA: 226] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
Abstract
Sequence variations in the triggering receptor expressed on myeloid cells 2 (TREM2) have been linked to an increased risk for neurodegenerative disorders such as Alzheimer's disease and frontotemporal lobar degeneration. In the brain, TREM2 is predominantly expressed in microglia. Several disease-associated TREM2 variants result in a loss of function by reducing microglial phagocytosis, impairing lipid sensing, preventing binding of lipoproteins and affecting shielding of amyloid plaques. We here investigate the consequences of TREM2 loss of function on the microglia transcriptome. Among the differentially expressed messenger RNAs in wild-type and Trem2-/- microglia, gene clusters are identified which represent gene functions in chemotaxis, migration and mobility. Functional analyses confirm that loss of TREM2 impairs appropriate microglial responses to injury and signals that normally evoke chemotaxis on multiple levels. In an ex vivo organotypic brain slice assay, absence of TREM2 reduces the distance migrated by microglia. Moreover, migration towards defined chemo-attractants is reduced upon ablation of TREM2 and can be rescued by TREM2 re-expression. In vivo, microglia lacking TREM2 migrate less towards injected apoptotic neurons, and outgrowth of microglial processes towards sites of laser-induced focal CNS damage in the somatosensory cortex is slowed. The apparent lack of chemotactic stimulation upon depletion of TREM2 is consistent with a stable expression profile of genes characterizing the homoeostatic signature of microglia.
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Affiliation(s)
- Fargol Mazaheri
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Nicolas Snaidero
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Institute for Clinical Neuroimmunology, Biomedical Center (BMC) and University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gernot Kleinberger
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Charlotte Madore
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Anna Daria
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Georg Werner
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Susanne Krasemann
- Institute for Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anja Capell
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
| | - Dietrich Trümbach
- Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Wolfgang Wurst
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Developmental Genetics, Technical University Munich-Weihenstephan, Neuherberg, Germany
| | - Bettina Brunner
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Sebastian Bultmann
- Department of Biology and Center for Integrated Protein Science Munich (CIPSM), Ludwig Maximilians-Universität München, Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Martin Kerschensteiner
- Institute for Clinical Neuroimmunology, Biomedical Center (BMC) and University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Misgeld
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Oleg Butovsky
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany .,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians Universität München, Munich, Germany
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120
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Affiliation(s)
- Knut Biber
- Department of Psychiatry, Section Molecular Psychiatry, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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121
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Daria A, Colombo A, Llovera G, Hampel H, Willem M, Liesz A, Haass C, Tahirovic S. Young microglia restore amyloid plaque clearance of aged microglia. EMBO J 2016; 36:583-603. [PMID: 28007893 DOI: 10.15252/embj.201694591] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 11/24/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by deposition of amyloid plaques, neurofibrillary tangles, and neuroinflammation. In order to study microglial contribution to amyloid plaque phagocytosis, we developed a novel ex vivo model by co-culturing organotypic brain slices from up to 20-month-old, amyloid-bearing AD mouse model (APPPS1) and young, neonatal wild-type (WT) mice. Surprisingly, co-culturing resulted in proliferation, recruitment, and clustering of old microglial cells around amyloid plaques and clearance of the plaque halo. Depletion of either old or young microglial cells prevented amyloid plaque clearance, indicating a synergistic effect of both populations. Exposing old microglial cells to conditioned media of young microglia or addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) was sufficient to induce microglial proliferation and reduce amyloid plaque size. Our data suggest that microglial dysfunction in AD may be reversible and their phagocytic ability can be modulated to limit amyloid accumulation. This novel ex vivo model provides a valuable system for identification, screening, and testing of compounds aimed to therapeutically reinforce microglial phagocytosis.
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Affiliation(s)
- Anna Daria
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Alessio Colombo
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
| | - Gemma Llovera
- Institute for Stroke and dementia research (ISD), Ludwig-Maximilians Universität München, Munich, Germany
| | - Heike Hampel
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Michael Willem
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany
| | - Arthur Liesz
- Institute for Stroke and dementia research (ISD), Ludwig-Maximilians Universität München, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Ludwig-Maximilians Universität München, Munich, Germany .,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Sabina Tahirovic
- German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany
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