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Li L, Li W, Jiang W, Xu R. Sulbactam protects neurons against double neurotoxicity of amyloid beta and glutamate load by upregulating glial glutamate transporter 1. Cell Death Discov 2024; 10:64. [PMID: 38320997 PMCID: PMC10847450 DOI: 10.1038/s41420-024-01827-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 02/08/2024] Open
Abstract
Amyloid beta (Abeta) synergistically enhances excitotoxicity of glutamate load by impairing glutamate transporter 1 (GLT1) expression and function, which exacerbates the development of Alzheimer's disease (AD). Our previous studies suggested that sulbactam can upregulate the expression levels and capacity of GLT1. Therefore, this study aims to investigate whether sulbactam improves neuronal tolerance against neurotoxicity of Abeta and glutamate load by up-regulating GLT1 in primary neuron-astrocyte co-cultures. Early postnatal P0-P1 Wistar rat pups' cortices were collected for primary neuron-astrocyte cultures. Hoechst-propidium iodide (HO-PI) stain and lactate dehydrogenase (LDH) assays were used to analyze neuronal death. Cell counting kit 8 (CCK8) was applied to determine cell viability. Immunofluorescence staining and western blotting were used to assess protein expressions including GLT1, B-cell lymphoma 2 (BCL2), BCL2 associated X (BAX), and cleaved caspase 3 (CCP3). Under the double effect of Abeta and glutamate load, more neurons were lost than that induced by Abeta or glutamate alone, shown as decreased cell viability, increased LDH concentration in the cultural medium, HO-PI positive stains, high CCP3 expression, and high BAX/BCL2 ratio resulting from increased BAX and decreased BCL2 expressions. Notably, pre-incubation with sulbactam significantly attenuated the neuronal loss and activation of apoptosis induced by both Abeta and glutamate in a dose-dependent manner. Simultaneously, both astrocytic and neuronal GLT1 expressions were upregulated after sulbactam incubation. Taken together, it could be concluded that sulbactam protected neurons against double neurotoxicity of Abeta and glutamate load by upregulating GLT1 expression. The conclusion provides evidence for potential intervention using sulbactam in AD research.
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Affiliation(s)
- Li Li
- The Central Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
| | - Wenbin Li
- Department of Pathophysiology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Wei Jiang
- Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Hebei Vascular Homeostasis Key Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Renhao Xu
- Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Hebei Vascular Homeostasis Key Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
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2
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Perrin F, Anderson LC, Mitchell SPC, Sinha P, Turchyna Y, Maesako M, Houser MCQ, Zhang C, Wagner SL, Tanzi RE, Berezovska O. PS1/gamma-secretase acts as rogue chaperone of glutamate transporter EAAT2/GLT-1 in Alzheimer's disease. RESEARCH SQUARE 2023:rs.3.rs-3495211. [PMID: 37986905 PMCID: PMC10659539 DOI: 10.21203/rs.3.rs-3495211/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The recently discovered interaction between presenilin 1 (PS1), a catalytic subunit of γ-secretase responsible for the generation of amyloid-β(Aβ) peptides, and GLT-1, the major glutamate transporter in the brain (EAAT2 in the human) may provide a mechanistic link between two important pathological aspects of Alzheimer's disease (AD): abnormal Aβoccurrence and neuronal network hyperactivity. In the current study, we employed a FRET-based approach, fluorescence lifetime imaging microscopy (FLIM), to characterize the PS1/GLT-1 interaction in its native environment in the brain tissue of sporadic AD (sAD) patients. There was significantly less interaction between PS1 and GLT-1 in sAD brains, compared to tissue from patients with frontotemporal lobar degeneration (FTLD), or non-demented age-matched controls. Since PS1 has been shown to adopt pathogenic "closed" conformation in sAD but not in FTLD, we assessed the impact of changes in PS1 conformation on the interaction. Familial AD (fAD) PS1 mutations which induce a "closed" PS1 conformation similar to that in sAD brain and gamma-secretase modulators (GSMs) which induce a "relaxed" conformation, reduced and increased the interaction, respectively. This indicates that PS1 conformation seems to have a direct effect on the interaction with GLT-1. Furthermore, using biotinylation/streptavidin pull-down, western blotting, and cycloheximide chase assays, we determined that the presence of PS1 increased GLT-1 cell surface expression and GLT-1 homomultimer formation, but did not impact GLT-1 protein stability. Together, the current findings suggest that the newly described PS1/GLT-1 interaction endows PS1 with chaperone activity, modulating GLT-1 transport to the cell surface and stabilizing the dimeric-trimeric states of the protein. The diminished PS1/GLT-1 interaction suggests that these functions of the interaction may not work properly in AD.
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3
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Bornstein R, Mulholland MT, Sedensky M, Morgan P, Johnson SC. Glutamine metabolism in diseases associated with mitochondrial dysfunction. Mol Cell Neurosci 2023; 126:103887. [PMID: 37586651 PMCID: PMC10773532 DOI: 10.1016/j.mcn.2023.103887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/10/2023] [Accepted: 08/13/2023] [Indexed: 08/18/2023] Open
Abstract
Mitochondrial dysfunction can arise from genetic defects or environmental exposures and impact a wide range of biological processes. Among these are metabolic pathways involved in glutamine catabolism, anabolism, and glutamine-glutamate cycling. In recent years, altered glutamine metabolism has been found to play important roles in the pathologic consequences of mitochondrial dysfunction. Glutamine is a pleiotropic molecule, not only providing an alternate carbon source to glucose in certain conditions, but also playing unique roles in cellular communication in neurons and astrocytes. Glutamine consumption and catabolic flux can be significantly altered in settings of genetic mitochondrial defects or exposure to mitochondrial toxins, and alterations to glutamine metabolism appears to play a particularly significant role in neurodegenerative diseases. These include primary mitochondrial diseases like Leigh syndrome (subacute necrotizing encephalopathy) and MELAS (mitochondrial myopathy with encephalopathy, lactic acidosis, and stroke-like episodes), as well as complex age-related neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Pharmacologic interventions targeting glutamine metabolizing and catabolizing pathways appear to provide some benefits in cell and animal models of these diseases, indicating glutamine metabolism may be a clinically relevant target. In this review, we discuss glutamine metabolism, mitochondrial disease, the impact of mitochondrial dysfunction on glutamine metabolic processes, glutamine in neurodegeneration, and candidate targets for therapeutic intervention.
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Affiliation(s)
- Rebecca Bornstein
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA
| | - Michael T Mulholland
- Department of Applied Sciences, Translational Bioscience, Northumbria University, Newcastle, UK
| | - Margaret Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA
| | - Phil Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA
| | - Simon C Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, USA; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, USA; Department of Neurology, University of Washington, Seattle, USA; Department of Applied Sciences, Translational Bioscience, Northumbria University, Newcastle, UK.
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4
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Jeong JH, Hong GL, Jeong YG, Lee NS, Kim DK, Park JY, Park M, Kim HM, Kim YE, Yoo YC, Han SY. Mixed Medicinal Mushroom Mycelia Attenuates Alzheimer's Disease Pathologies In Vitro and In Vivo. Curr Issues Mol Biol 2023; 45:6775-6789. [PMID: 37623247 PMCID: PMC10453438 DOI: 10.3390/cimb45080428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/10/2023] [Accepted: 08/13/2023] [Indexed: 08/26/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by memory impairment and existence of amyloid-β (Aβ) plaques and neuroinflammation. Due to the pivotal role of oxidative damage in AD, natural antioxidative agents, such as polyphenol-rich fungi, have garnered scientific scrutiny. Here, the aqueous extract of mixed medicinal mushroom mycelia (MMMM)-Phellinus linteus, Ganoderma lucidum, and Inonotus obliquus-cultivated on a barley medium was assessed for its anti-AD effects. Neuron-like PC12 cells, which were subjected to Zn2+, an Aβ aggregator, were employed as an in vitro AD model. The cells pretreated with or without MMMM were assayed for Aβ immunofluorescence, cell viability, reactive oxygen species (ROS), apoptosis, and antioxidant enzyme activity. Then, 5XFAD mice were administered with 30 mg/kg/day MMMM for 8 weeks and underwent memory function tests and histologic analyses. In vitro results demonstrated that the cells pretreated with MMMM exhibited attenuation in Aβ immunofluorescence, ROS accumulation, and apoptosis, and incrementation in cell viability and antioxidant enzyme activity. In vivo results revealed that 5XFAD mice administered with MMMM showed attenuation in memory impairment and histologic deterioration such as Aβ plaque accumulation and neuroinflammation. MMMM might mitigate AD-associated memory impairment and cerebral pathologies, including Aβ plaque accumulation and neuroinflammation, by impeding Aβ-induced neurotoxicity.
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Affiliation(s)
- Ji Heun Jeong
- Armed Forces Medical Research Institute (AFMRI), Daejeon 34059, Republic of Korea;
| | - Geum-Lan Hong
- Department of Anatomy, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; (G.-L.H.); (Y.G.J.); (N.S.L.); (D.K.K.)
| | - Young Gil Jeong
- Department of Anatomy, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; (G.-L.H.); (Y.G.J.); (N.S.L.); (D.K.K.)
| | - Nam Seob Lee
- Department of Anatomy, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; (G.-L.H.); (Y.G.J.); (N.S.L.); (D.K.K.)
| | - Do Kyung Kim
- Department of Anatomy, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; (G.-L.H.); (Y.G.J.); (N.S.L.); (D.K.K.)
| | - Jong Yea Park
- Giunchan Co., Ltd., Cheonan 31035, Republic of Korea; (J.Y.P.); (M.P.); (H.M.K.); (Y.E.K.)
| | - Mina Park
- Giunchan Co., Ltd., Cheonan 31035, Republic of Korea; (J.Y.P.); (M.P.); (H.M.K.); (Y.E.K.)
| | - Hyun Min Kim
- Giunchan Co., Ltd., Cheonan 31035, Republic of Korea; (J.Y.P.); (M.P.); (H.M.K.); (Y.E.K.)
| | - Ya El Kim
- Giunchan Co., Ltd., Cheonan 31035, Republic of Korea; (J.Y.P.); (M.P.); (H.M.K.); (Y.E.K.)
| | - Yung Choon Yoo
- Department of Microbiology, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea;
| | - Seung Yun Han
- Department of Anatomy, College of Medicine, Konyang University, Daejeon 35365, Republic of Korea; (G.-L.H.); (Y.G.J.); (N.S.L.); (D.K.K.)
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5
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Madeira D, Lopes CR, Simões AP, Canas PM, Cunha RA, Agostinho P. Astrocytic A 2A receptors silencing negatively impacts hippocampal synaptic plasticity and memory of adult mice. Glia 2023. [PMID: 37183905 DOI: 10.1002/glia.24384] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/16/2023]
Abstract
Astrocytes are wired to bidirectionally communicate with neurons namely with synapses, thus shaping synaptic plasticity, which in the hippocampus is considered to underlie learning and memory. Adenosine A2A receptors (A2A R) are a potential candidate to modulate this bidirectional communication, since A2A R regulate synaptic plasticity and memory and also control key astrocytic functions. Nonetheless, little is known about the role of astrocytic A2A R in synaptic plasticity and hippocampal-dependent memory. Here, we investigated the impact of genetic silencing astrocytic A2A R on hippocampal synaptic plasticity and memory of adult mice. The genetic A2A R silencing in astrocytes was accomplished by a bilateral injection into the CA1 hippocampal area of a viral construct (AAV5-GFAP-GFP-Cre) that inactivate A2A R expression in astrocytes of male adult mice carrying "floxed" A2A R gene, as confirmed by A2A R binding assays. Astrocytic A2A R silencing alters astrocytic morphology, typified by an increment of astrocytic arbor complexity, and led to deficits in spatial reference memory and compromised hippocampal synaptic plasticity, typified by a reduction of LTP magnitude and a shift of synaptic long-term depression (LTD) toward LTP. These data indicate that astrocytic A2A R control astrocytic morphology and influence hippocampal synaptic plasticity and memory of adult mice in a manner different from neuronal A2A R.
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Affiliation(s)
- Daniela Madeira
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Cátia R Lopes
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Ana P Simões
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Paula M Canas
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Rodrigo A Cunha
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
| | - Paula Agostinho
- Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
- Center for Neuroscience and Cell Biology- University of Coimbra (CNC- UC), Coimbra, Portugal
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6
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Shen Z, Li ZY, Yu MT, Tan KL, Chen S. Metabolic perspective of astrocyte dysfunction in Alzheimer's disease and type 2 diabetes brains. Biomed Pharmacother 2023; 158:114206. [PMID: 36916433 DOI: 10.1016/j.biopha.2022.114206] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/30/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023] Open
Abstract
The term type III diabetes (T3DM) has been proposed for Alzheimer's disease (AD) due to the shared molecular and cellular features between type 2 diabetes (T2DM) and insulin resistance-associated memory deficits and cognitive decline in elderly individuals. Astrocytes elicit neuroprotective or deleterious effects in AD progression and severity. Patients with T2DM are at a high risk of cognitive impairment, and targeting astrocytes might be promising in alleviating neurodegeneration in the diabetic brain. Recent studies focusing on cell-specific activities in the brain have revealed the important role of astrocytes in brain metabolism (e.g., glucose metabolism, lipid metabolism), neurovascular coupling, synapses, and synaptic plasticity. In this review, we discuss how astrocytes and their dysfunction result in multiple pathological and clinical features of AD and T2DM from a metabolic perspective and the potential comorbid mechanism in these two diseases from the perspective of astrocytes.
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Affiliation(s)
- Zheng Shen
- Zunyi Medical University, Zhuhai Campus, Zhuhai, Guangdong 519041, China
| | - Zheng-Yang Li
- Zunyi Medical University, Zhuhai Campus, Zhuhai, Guangdong 519041, China
| | - Meng-Ting Yu
- Zunyi Medical University, Zhuhai Campus, Zhuhai, Guangdong 519041, China
| | - Kai-Leng Tan
- Institute of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
| | - Si Chen
- Zunyi Medical University, Zhuhai Campus, Zhuhai, Guangdong 519041, China.
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7
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Functional investigation of SLC1A2 variants associated with epilepsy. Cell Death Dis 2022; 13:1063. [PMID: 36543780 PMCID: PMC9772344 DOI: 10.1038/s41419-022-05457-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 12/24/2022]
Abstract
Epilepsy is a common neurological disorder and glutamate excitotoxicity plays a key role in epileptic pathogenesis. Astrocytic glutamate transporter GLT-1 is responsible for preventing excitotoxicity via clearing extracellular accumulated glutamate. Previously, three variants (G82R, L85P, and P289R) in SLC1A2 (encoding GLT-1) have been clinically reported to be associated with epilepsy. However, the functional validation and underlying mechanism of these GLT-1 variants in epilepsy remain undetermined. In this study, we reported that these disease-linked mutants significantly decrease glutamate uptake, cell membrane expression of the glutamate transporter, and glutamate-elicited current. Additionally, we found that these variants may disturbed stromal-interacting molecule 1 (STIM1)/Orai1-mediated store-operated Ca2+ entry (SOCE) machinery in the endoplasmic reticulum (ER), in which GLT-1 may be a new partner of SOCE. Furthermore, knock-in mice with disease-associated variants showed a hyperactive phenotype accompanied by reduced glutamate transporter expression. Therefore, GLT-1 is a promising and reliable therapeutic target for epilepsy interventions.
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van den Berg M, Adhikari MH, Verschuuren M, Pintelon I, Vasilkovska T, Van Audekerke J, Missault S, Heymans L, Ponsaerts P, De Vos WH, Van der Linden A, Keliris GA, Verhoye M. Altered basal forebrain function during whole-brain network activity at pre- and early-plaque stages of Alzheimer's disease in TgF344-AD rats. Alzheimers Res Ther 2022; 14:148. [PMID: 36217211 PMCID: PMC9549630 DOI: 10.1186/s13195-022-01089-2] [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: 06/24/2022] [Accepted: 09/22/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND Imbalanced synaptic transmission appears to be an early driver in Alzheimer's disease (AD) leading to brain network alterations. Early detection of altered synaptic transmission and insight into mechanisms causing early synaptic alterations would be valuable treatment strategies. This study aimed to investigate how whole-brain networks are influenced at pre- and early-plague stages of AD and if these manifestations are associated with concomitant cellular and synaptic deficits. METHODS: To this end, we used an established AD rat model (TgF344-AD) and employed resting state functional MRI and quasi-periodic pattern (QPP) analysis, a method to detect recurrent spatiotemporal motifs of brain activity, in parallel with state-of-the-art immunohistochemistry in selected brain regions. RESULTS At the pre-plaque stage, QPPs in TgF344-AD rats showed decreased activity of the basal forebrain (BFB) and the default mode-like network. Histological analyses revealed increased astrocyte abundance restricted to the BFB, in the absence of amyloid plaques, tauopathy, and alterations in a number of cholinergic, gaba-ergic, and glutamatergic synapses. During the early-plaque stage, when mild amyloid-beta (Aβ) accumulation was observed in the cortex and hippocampus, QPPs in the TgF344-AD rats normalized suggesting the activation of compensatory mechanisms during this early disease progression period. Interestingly, astrogliosis observed in the BFB at the pre-plaque stage was absent at the early-plaque stage. Moreover, altered excitatory/inhibitory balance was observed in cortical regions belonging to the default mode-like network. In wild-type rats, at both time points, peak activity in the BFB preceded peak activity in other brain regions-indicating its modulatory role during QPPs. However, this pattern was eliminated in TgF344-AD suggesting that alterations in BFB-directed neuromodulation have a pronounced impact in network function in AD. CONCLUSIONS This study demonstrates the value of rsfMRI and advanced network analysis methods to detect early alterations in BFB function in AD, which could aid early diagnosis and intervention in AD. Restoring the global synaptic transmission, possibly by modulating astrogliosis in the BFB, might be a promising therapeutic strategy to restore brain network function and delay the onset of symptoms in AD.
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Affiliation(s)
- Monica van den Berg
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Mohit H. Adhikari
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marlies Verschuuren
- grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Isabel Pintelon
- grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Tamara Vasilkovska
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Johan Van Audekerke
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Stephan Missault
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Loran Heymans
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Peter Ponsaerts
- grid.5284.b0000 0001 0790 3681Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Winnok H. De Vos
- grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Annemie Van der Linden
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Georgios A. Keliris
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.511960.aInstitute of Computer Science, Foundation for Research & Technology - Hellas, Heraklion, Crete, Greece
| | - Marleen Verhoye
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1 2610 Wilrijk, Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
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Zhang H, Jiang X, Ma L, Wei W, Li Z, Chang S, Wen J, Sun J, Li H. Role of Aβ in Alzheimer’s-related synaptic dysfunction. Front Cell Dev Biol 2022; 10:964075. [PMID: 36092715 PMCID: PMC9459380 DOI: 10.3389/fcell.2022.964075] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Synaptic dysfunction is closely related to Alzheimer’s disease (AD) which is also recognized as synaptic disorder. β-amyloid (Aβ) is one of the main pathogenic factors in AD, which disrupts synaptic plasticity and mediates the synaptic toxicity through different mechanisms. Aβ disrupts glutamate receptors, such as NMDA and AMPA receptors, which mediates calcium dyshomeostasis and damages synapse plasticity characterized by long-term potentiation (LTP) suppression and long-term depression (LTD) enhancement. As Aβ stimulates and Ca2+ influx, microglial cells and astrocyte can be activated and release cytokines, which reduces glutamate uptake and further impair synapse function. Besides, extracellular glutamate accumulation induced by Aβ mediates synapse toxicity resulting from reduced glutamate receptors and glutamate spillovers. Aβ also mediates synaptic dysfunction by acting on various signaling pathways and molecular targets, disrupting mitochondria and energy metabolism. In addition, Aβ overdeposition aggravates the toxic damage of hyperphosphorylated tau to synapses. Synaptic dysfunction plays a critical role in cognitive impairment of AD. The review addresses the possible mechanisms by which Aβ mediates AD-related synaptic impairment from distant perspectives.
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Affiliation(s)
- Huiqin Zhang
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xuefan Jiang
- Beijing University of Chinese Medicine, Beijing, China
| | - Lina Ma
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wei Wei
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zehui Li
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Surui Chang
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jiayu Wen
- Beijing University of Chinese Medicine, Beijing, China
| | - Jiahui Sun
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Hao Li
- Institute of Geriatrics, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Hao Li,
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10
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Wood OWG, Yeung JHY, Faull RLM, Kwakowsky A. EAAT2 as a therapeutic research target in Alzheimer's disease: A systematic review. Front Neurosci 2022; 16:952096. [PMID: 36033606 PMCID: PMC9399514 DOI: 10.3389/fnins.2022.952096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/14/2022] [Indexed: 11/23/2022] Open
Abstract
Glutamate is the main excitatory neurotransmitter in the human central nervous system, responsible for a wide variety of normal physiological processes. Glutamatergic metabolism and its sequestration are tightly regulated in the normal human brain, and it has been demonstrated that dysregulation of the glutamatergic system can have wide-ranging effects both in acute brain injury and neurodegenerative diseases. The excitatory amino acid transporter 2 (EAAT2) is the dominant glutamatergic transporter in the human brain, responsible for efficient removal of glutamate from the synaptic cleft for recycling within glial cells. As such, it has a key role in maintaining excitatory-inhibitory homeostasis. Animal studies have demonstrated dysregulation or alterations of EAAT2 expression can have implications in neurodegenerative disorders. Despite extensive research into glutamatergic alterations in AD mouse models, there is a lack of studies examining the expression of EAAT2 within the AD human brain. In this systematic review, 29 articles were identified that either analyzed EAAT2 expression in the AD human brain or used a human-derived cell culture. Studies were inconclusive as to whether EAAT2 was upregulated or downregulated in AD. However, changes in localization and correlation between EAAT2 expression and symptomatology was noted. These findings implicate EAAT2 alterations as a key process in AD progression and highlight the need for further research into the characterization of EAAT2 processes in normal physiology and disease in human tissue and to identify compounds that can act as EAAT2 neuromodulators.
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Affiliation(s)
- Oliver W. G. Wood
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Jason H. Y. Yeung
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Richard L. M. Faull
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Andrea Kwakowsky
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Pharmacology and Therapeutics, Galway Neuroscience Centre, School of Medicine, Ollscoil na Gaillimhe – University of Galway, Galway, Ireland
- *Correspondence: Andrea Kwakowsky
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11
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Bioactive human Alzheimer brain soluble Aβ: pathophysiology and therapeutic opportunities. Mol Psychiatry 2022; 27:3182-3191. [PMID: 35484241 DOI: 10.1038/s41380-022-01589-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 12/16/2022]
Abstract
The accumulation of amyloid-β protein (Aβ) plays an early role in the pathogenesis of Alzheimer's disease (AD). The precise mechanism of how Aβ accumulation leads to synaptic dysfunction and cognitive impairment remains unclear but is likely due to small soluble oligomers of Aβ (oAβ). Most studies have used chemical synthetic or cell-secreted Aβ oligomers to study their pathogenic mechanisms, but the Aβ derived from human AD brain tissue is less well characterized. Here we review updated knowledge on the extraction and characterization of bioactive human AD brain oAβ and the mechanisms by which they cause hippocampal synaptic dysfunction. Human AD brain-derived oAβ can impair hippocampal long-term potentiation (LTP) and enhance long-term depression (LTD). Many studies suggest that oAβ may directly disrupt neuronal NMDA receptors, AMPA receptors and metabotropic glutamate receptors (mGluRs). oAβ also impairs astrocytic synaptic functions, including glutamate uptake, D-serine release, and NMDA receptor function. We also discuss oAβ-induced neuronal hyperexcitation. These results may suggest a multi-target approach for the treatment of AD, including both oAβ neutralization and reversal of glutamate-mediated excitotoxicity.
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12
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Lee HG, Wheeler MA, Quintana FJ. Function and therapeutic value of astrocytes in neurological diseases. Nat Rev Drug Discov 2022; 21:339-358. [PMID: 35173313 PMCID: PMC9081171 DOI: 10.1038/s41573-022-00390-x] [Citation(s) in RCA: 177] [Impact Index Per Article: 88.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2022] [Indexed: 12/20/2022]
Abstract
Astrocytes are abundant glial cells in the central nervous system (CNS) that perform diverse functions in health and disease. Astrocyte dysfunction is found in numerous diseases, including multiple sclerosis, Alzheimer disease, Parkinson disease, Huntington disease and neuropsychiatric disorders. Astrocytes regulate glutamate and ion homeostasis, cholesterol and sphingolipid metabolism and respond to environmental factors, all of which have been implicated in neurological diseases. Astrocytes also exhibit significant heterogeneity, driven by developmental programmes and stimulus-specific cellular responses controlled by CNS location, cell-cell interactions and other mechanisms. In this Review, we highlight general mechanisms of astrocyte regulation and their potential as therapeutic targets, including drugs that alter astrocyte metabolism, and therapies that target transporters and receptors on astrocytes. Emerging ideas, such as engineered probiotics and glia-to-neuron conversion therapies, are also discussed. We further propose a concise nomenclature for astrocyte subsets that we use to highlight the roles of astrocytes and specific subsets in neurological diseases.
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Affiliation(s)
- Hong-Gyun Lee
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael A Wheeler
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Francisco J Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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13
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Brain Metabolic Alterations in Alzheimer's Disease. Int J Mol Sci 2022; 23:ijms23073785. [PMID: 35409145 PMCID: PMC8998942 DOI: 10.3390/ijms23073785] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 01/27/2023] Open
Abstract
The brain is one of the most energy-consuming organs in the body. Satisfying such energy demand requires compartmentalized, cell-specific metabolic processes, known to be complementary and intimately coupled. Thus, the brain relies on thoroughly orchestrated energy-obtaining agents, processes and molecular features, such as the neurovascular unit, the astrocyte-neuron metabolic coupling, and the cellular distribution of energy substrate transporters. Importantly, early features of the aging process are determined by the progressive perturbation of certain processes responsible for adequate brain energy supply, resulting in brain hypometabolism. These age-related brain energy alterations are further worsened during the prodromal stages of neurodegenerative diseases, namely Alzheimer's disease (AD), preceding the onset of clinical symptoms, and are anatomically and functionally associated with the loss of cognitive abilities. Here, we focus on concrete neuroenergetic features such as the brain's fueling by glucose and lactate, the transporters and vascular system guaranteeing its supply, and the metabolic interactions between astrocytes and neurons, and on its neurodegenerative-related disruption. We sought to review the principles underlying the metabolic dimension of healthy and AD brains, and suggest that the integration of these concepts in the preventive, diagnostic and treatment strategies for AD is key to improving the precision of these interventions.
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14
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Viola KL, Bicca MA, Bebenek AM, Kranz DL, Nandwana V, Waters EA, Haney CR, Lee M, Gupta A, Brahmbhatt Z, Huang W, Chang TT, Peck A, Valdez C, Dravid VP, Klein WL. The Therapeutic and Diagnostic Potential of Amyloid β Oligomers Selective Antibodies to Treat Alzheimer's Disease. Front Neurosci 2022; 15:768646. [PMID: 35046767 PMCID: PMC8761808 DOI: 10.3389/fnins.2021.768646] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/09/2021] [Indexed: 01/10/2023] Open
Abstract
Improvements have been made in the diagnosis of Alzheimer’s disease (AD), manifesting mostly in the development of in vivo imaging methods that allow for the detection of pathological changes in AD by magnetic resonance imaging (MRI) and positron emission tomography (PET) scans. Many of these imaging methods, however, use agents that probe amyloid fibrils and plaques–species that do not correlate well with disease progression and are not present at the earliest stages of the disease. Amyloid β oligomers (AβOs), rather, are now widely accepted as the Aβ species most germane to AD onset and progression. Here we report evidence further supporting the role of AβOs as pathological instigators of AD and introduce promising anti-AβO diagnostic probes capable of distinguishing the 5xFAD mouse model from wild type mice by PET and MRI. In a developmental study, Aβ oligomers in 5xFAD mice were found to appear at 3 months of age, just prior to the onset of memory dysfunction, and spread as memory worsened. The increase of AβOs is prominent in the subiculum and correlates with concomitant development of reactive astrocytosis. The impact of these AβOs on memory is in harmony with findings that intraventricular injection of synthetic AβOs into wild type mice induced hippocampal dependent memory dysfunction within 24 h. Compelling support for the conclusion that endogenous AβOs cause memory loss was found in experiments showing that intranasal inoculation of AβO-selective antibodies into 5xFAD mice completely restored memory function, measured 30–40 days post-inoculation. These antibodies, which were modified to give MRI and PET imaging probes, were able to distinguish 5xFAD mice from wild type littermates. These results provide strong support for the role of AβOs in instigating memory loss and salient AD neuropathology, and they demonstrate that AβO selective antibodies have potential both for therapeutics and for diagnostics.
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Affiliation(s)
- Kirsten L Viola
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Maira A Bicca
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Adrian M Bebenek
- Illinois Mathematics and Science Academy, Aurora, IL, United States
| | - Daniel L Kranz
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Vikas Nandwana
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, United States
| | - Emily A Waters
- Center for Advanced Molecular Imaging, Northwestern University, Evanston, IL, United States
| | - Chad R Haney
- Center for Advanced Molecular Imaging, Northwestern University, Evanston, IL, United States
| | - Maxwell Lee
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Abhay Gupta
- Illinois Mathematics and Science Academy, Aurora, IL, United States
| | | | - Weijian Huang
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Ting-Tung Chang
- Small Animal Imaging Facility, Van Andel Research Institute, Grand Rapids, MI, United States.,Laboratory of Translational Imaging, Van Andel Research Institute, Grand Rapids, MI, United States
| | - Anderson Peck
- Small Animal Imaging Facility, Van Andel Research Institute, Grand Rapids, MI, United States.,Laboratory of Translational Imaging, Van Andel Research Institute, Grand Rapids, MI, United States
| | - Clarissa Valdez
- Department of Neurobiology, Northwestern University, Evanston, IL, United States
| | - Vinayak P Dravid
- Illinois Mathematics and Science Academy, Aurora, IL, United States
| | - William L Klein
- Department of Neurobiology, Northwestern University, Evanston, IL, United States.,Department of Neurology, Northwestern University, Chicago, IL, United States
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15
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Lopes CR, Amaral IM, Pereira MF, Lopes JP, Madeira D, Canas PM, Cunha RA, Agostinho P. Impact of blunting astrocyte activity on hippocampal synaptic plasticity in a mouse model of early Alzheimer's disease based on amyloid-β peptide exposure. J Neurochem 2022; 160:556-567. [PMID: 35043392 DOI: 10.1111/jnc.15575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/27/2021] [Accepted: 01/12/2022] [Indexed: 11/27/2022]
Abstract
Amyloid-β peptides (Aβ) accumulate in the brain since early Alzheimer's disease (AD) and dysregulate hippocampal synaptic plasticity, the neurophysiological basis of memory. Although the relationship between long-term potentiation (LTP) and memory processes is well established, there is also evidence that long-term depression (LTD) may be crucial for learning and memory. Alterations in synaptic plasticity, namely in LTP, can be due to communication failures between astrocytes and neurons; however, little is known about astrocytes´ ability to control hippocampal LTD, particularly in AD-like conditions. We now aimed to test the involvement of astrocytes in changes of hippocampal LTP and LTD triggered by Aβ1-42 , taking advantage of L-α-aminoadipate (L-AA), a gliotoxin that blunts astrocytic function. The effects of Aβ1-42 exposure was tested in two different experimental paradigms: ex vivo (hippocampal slices superfusion) and in vivo (intracerebroventricular injection), which were previously validated to impair memory and hippocampal synaptic plasticity, two features of early AD. Blunting astrocytic function with L-AA reduced LTP and LTD amplitude in hippocampal slices from control mice but the effect on LTD was less evident, suggesting that astrocytes have a greater influence on LTP than on LTD under non-pathological conditions. However, under AD conditions, blunting astrocytes did not consistently alter the reduction of LTP magnitude and reverted the LTD-to-LTP shift caused by both ex vivo and in vivo Aβ1-42 exposure. This shows that astrocytes were responsible for the hippocampal LTD-to-LTP shift observed in early AD conditions, reinforcing the interest of strategies targeting astrocytes to restore memory and synaptic plasticity deficits present in early AD.
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Affiliation(s)
- Cátia R Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Portugal
| | - Inês M Amaral
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | | | - João P Lopes
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Daniela Madeira
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Portugal
| | - Paula M Canas
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal
| | - Rodrigo A Cunha
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Portugal
| | - Paula Agostinho
- Center for Neuroscience and Cell Biology, CNC, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, FMUC, Portugal
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16
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Chen Y, Li Y, Du M, Yu J, Gao F, Yuan Z, Chen Z. Ultrasound Neuromodulation: Integrating Medicine and Engineering for Neurological Disease Treatment. BIO INTEGRATION 2021. [DOI: 10.15212/bioi-2020-0026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Abstract Neurological diseases associated with dysfunctions of neural circuits, including Alzheimer’s disease (AD), depression and epilepsy, have been increasingly prevalent. To tackle these issues, artificial stimulation or regulation of specific neural circuits and
nuclei are employed to alleviate or cure certain neurological diseases. In particular, ultrasound neuromodulation has been an emerging interdisciplinary approach, which integrates medicine and engineering methodologies in the treatment. With the development of medicine and engineering, ultrasound
neuromodulation has gradually been applied in the treatment of central nervous system diseases. In this review, we aimed to summarize the mechanism of ultrasound neuromodulation and the advances of focused ultrasound (FUS) in neuromodulation in recent years, with a special emphasis on its
application in central nervous system disease treatment. FUS showed great feasibility in the treatment of epilepsy, tremor, AD, depression, and brain trauma. We also suggested future directions of ultrasound neuromodulation in clinical settings, with a focus on its fusion with genetic engineering
or nanotechnology.
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Affiliation(s)
- Yuhao Chen
- Department of Ultrasound Medicine, Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
| | - Yue Li
- Department of Ultrasound Medicine, Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
| | - Meng Du
- Medical Imaging Centre, First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, China
| | - Jinsui Yu
- Department of Ultrasound Medicine, Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
| | - Fei Gao
- Cancer Center, Faculty of Health Sciences, Centre for Cognitive and Brain Sciences, University of Macau, Macau SAR 999078, China
| | - Zhen Yuan
- Cancer Center, Faculty of Health Sciences, Centre for Cognitive and Brain Sciences, University of Macau, Macau SAR 999078, China
| | - Zhiyi Chen
- Medical Imaging Centre, First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, China
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17
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Cuestas Torres DM, Cardenas FP. Synaptic plasticity in Alzheimer's disease and healthy aging. Rev Neurosci 2021; 31:245-268. [PMID: 32250284 DOI: 10.1515/revneuro-2019-0058] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/01/2019] [Indexed: 12/17/2022]
Abstract
The strength and efficiency of synaptic connections are affected by the environment or the experience of the individual. This property, called synaptic plasticity, is directly related to memory and learning processes and has been modeled at the cellular level. These types of cellular memory and learning models include specific stimulation protocols that generate a long-term strengthening of the synapses, called long-term potentiation, or a weakening of the said long-term synapses, called long-term depression. Although, for decades, researchers have believed that the main cause of the cognitive deficit that characterizes Alzheimer's disease (AD) and aging was the loss of neurons, the hypothesis of an imbalance in the cellular and molecular mechanisms of synaptic plasticity underlying this deficit is currently widely accepted. An understanding of the molecular and cellular changes underlying the process of synaptic plasticity during the development of AD and aging will direct future studies to specific targets, resulting in the development of much more efficient and specific therapeutic strategies. In this review, we classify, discuss, and describe the main findings related to changes in the neurophysiological mechanisms of synaptic plasticity in excitatory synapses underlying AD and aging. In addition, we suggest possible mechanisms in which aging can become a high-risk factor for the development of AD and how its development could be prevented or slowed.
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Affiliation(s)
- Diana Marcela Cuestas Torres
- Departamento de Psicología and Departamento de Biología, Laboratorio de Neurociencia y Comportamiento, Universidad de los Andes, Cra 1 N° 18A-12, CP 111711, Bogotá, Colombia
| | - Fernando P Cardenas
- Departamento de Psicología, Laboratorio de Neurociencia y Comportamiento, Universidad de los Andes, Cra 1 N° 18A-12, CP 111711, Bogotá, Colombia
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18
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Mulica P, Grünewald A, Pereira SL. Astrocyte-Neuron Metabolic Crosstalk in Neurodegeneration: A Mitochondrial Perspective. Front Endocrinol (Lausanne) 2021; 12:668517. [PMID: 34025580 PMCID: PMC8138625 DOI: 10.3389/fendo.2021.668517] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/22/2021] [Indexed: 12/21/2022] Open
Abstract
Converging evidence made clear that declining brain energetics contribute to aging and are implicated in the initiation and progression of neurodegenerative disorders such as Alzheimer's and Parkinson's disease. Indeed, both pathologies involve instances of hypometabolism of glucose and oxygen in the brain causing mitochondrial dysfunction, energetic failure and oxidative stress. Importantly, recent evidence suggests that astrocytes, which play a key role in supporting neuronal function and metabolism, might contribute to the development of neurodegenerative diseases. Therefore, exploring how the neuro-supportive role of astrocytes may be impaired in the context of these disorders has great therapeutic potential. In the following, we will discuss some of the so far identified features underlining the astrocyte-neuron metabolic crosstalk. Thereby, special focus will be given to the role of mitochondria. Furthermore, we will report on recent advancements concerning iPSC-derived models used to unravel the metabolic contribution of astrocytes to neuronal demise. Finally, we discuss how mitochondrial dysfunction in astrocytes could contribute to inflammatory signaling in neurodegenerative diseases.
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Affiliation(s)
- Patrycja Mulica
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Anne Grünewald
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Sandro L. Pereira
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
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19
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Abstract
Significance: Unique to the branched-chain aminotransferase (BCAT) proteins is their redox-active CXXC motif. Subjected to post-translational modification by reactive oxygen species and reactive nitrogen species, these proteins have the potential to adopt numerous cellular roles, which may be fundamental to their role in oncogenesis and neurodegenerative diseases. An understanding of the interplay of the redox regulation of BCAT with important cell signaling mechanisms will identify new targets for future therapeutics. Recent Advances: The BCAT proteins have been assigned novel thiol oxidoreductase activity that can accelerate the refolding of proteins, in particular when S-glutathionylated, supporting a chaperone role for BCAT in protein folding. Other metabolic proteins were also shown to have peroxide-mediated redox associations with BCAT, indicating that the cellular function of BCAT is more diverse. Critical Issues: While the role of branched-chain amino acid metabolism and its metabolites has dominated aspects of cancer research, less is known about the role of BCAT. The importance of the CXXC motif in regulating the BCAT activity under hypoxic conditions, a characteristic of tumors, has not been addressed. Understanding how these proteins operate under various cellular redox conditions will become important, in particular with respect to their moonlighting roles. Future Directions: Advances in the quantification of thiols, their measurement, and the manipulation of metabolons that rely on redox-based interactions should accelerate the investigation of the cellular role of moonlighting proteins such as BCAT. Given the importance of cross talk between signaling pathways, research should focus more on these "housekeeping" proteins paying attention to their wider application. Antioxid. Redox Signal. 34, 1048-1067.
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Affiliation(s)
- Myra Elizabeth Conway
- Department of Applied Science, University of the West of England, Bristol, United Kingdom
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20
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Doustar J, Rentsendorj A, Torbati T, Regis GC, Fuchs D, Sheyn J, Mirzaei N, Graham SL, Shah PK, Mastali M, Van Eyk JE, Black KL, Gupta VK, Mirzaei M, Koronyo Y, Koronyo‐Hamaoui M. Parallels between retinal and brain pathology and response to immunotherapy in old, late-stage Alzheimer's disease mouse models. Aging Cell 2020; 19:e13246. [PMID: 33090673 PMCID: PMC7681044 DOI: 10.1111/acel.13246] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/14/2020] [Accepted: 09/09/2020] [Indexed: 12/20/2022] Open
Abstract
Despite growing evidence for the characteristic signs of Alzheimer's disease (AD) in the neurosensory retina, our understanding of retina-brain relationships, especially at advanced disease stages and in response to therapy, is lacking. In transgenic models of AD (APPSWE/PS1∆E9; ADtg mice), glatiramer acetate (GA) immunomodulation alleviates disease progression in pre- and early-symptomatic disease stages. Here, we explored the link between retinal and cerebral AD-related biomarkers, including response to GA immunization, in cohorts of old, late-stage ADtg mice. This aged model is considered more clinically relevant to the age-dependent disease. Levels of synaptotoxic amyloid β-protein (Aβ)1-42, angiopathic Aβ1-40, non-amyloidogenic Aβ1-38, and Aβ42/Aβ40 ratios tightly correlated between paired retinas derived from oculus sinister (OS) and oculus dexter (OD) eyes, and between left and right posterior brain hemispheres. We identified lateralization of Aβ burden, with one-side dominance within paired retinal and brain tissues. Importantly, OS and OD retinal Aβ levels correlated with their cerebral counterparts, with stronger contralateral correlations and following GA immunization. Moreover, immunomodulation in old ADtg mice brought about reductions in cerebral vascular and parenchymal Aβ deposits, especially of large, dense-core plaques, and alleviation of microgliosis and astrocytosis. Immunization further enhanced cerebral recruitment of peripheral myeloid cells and synaptic preservation. Mass spectrometry analysis identified new parallels in retino-cerebral AD-related pathology and response to GA immunization, including restoration of homeostatic glutamine synthetase expression. Overall, our results illustrate the viability of immunomodulation-guided CNS repair in old AD model mice, while shedding light onto similar retino-cerebral responses to intervention, providing incentives to explore retinal AD biomarkers.
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Affiliation(s)
- Jonah Doustar
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Altan Rentsendorj
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Tania Torbati
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
- College of Osteopathic Medicine of the PacificWestern University of Health SciencesPomonaCAUSA
| | - Giovanna C. Regis
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Dieu‐Trang Fuchs
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Julia Sheyn
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Nazanin Mirzaei
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Stuart L. Graham
- Department of Clinical MedicineMacquarie UniversitySydneyNSWAustralia
- Save Sight InstituteSydney UniversitySydneyNSWAustralia
| | - Prediman K. Shah
- Oppenheimer Atherosclerosis Research CenterCedars‐Sinai Heart InstituteLos AngelesCAUSA
| | - Mitra Mastali
- Department of Biomedical SciencesCedars‐Sinai Medical CenterLos AngelesCAUSA
- Cedars‐Sinai Medical CenterSmidt Heart InstituteLos AngelesCAUSA
| | - Jennifer E. Van Eyk
- Department of Biomedical SciencesCedars‐Sinai Medical CenterLos AngelesCAUSA
- Barbara Streisand Women’s Heart CenterCedars‐Sinai Medical CenterLos AngelesCAUSA
- Department of MedicineCedars‐Sinai Medical CenterLos AngelesCAUSA
| | - Keith L. Black
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Vivek K. Gupta
- Department of Molecular SciencesMacquarie UniversitySydneyNSWAustralia
| | - Mehdi Mirzaei
- Department of Clinical MedicineMacquarie UniversitySydneyNSWAustralia
- Department of Molecular SciencesMacquarie UniversitySydneyNSWAustralia
- Australian Proteome Analysis FacilityMacquarie UniversitySydneyNSWAustralia
| | - Yosef Koronyo
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
| | - Maya Koronyo‐Hamaoui
- Department of NeurosurgeryCedars‐Sinai Medical CenterMaxine Dunitz Neurosurgical Research InstituteLos AngelesCAUSA
- Department of Biomedical SciencesCedars‐Sinai Medical CenterLos AngelesCAUSA
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21
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Braidy N, Alicajic H, Pow D, Smith J, Jugder BE, Brew BJ, Nicolazzo JA, Guillemin GJ. Potential Mechanism of Cellular Uptake of the Excitotoxin Quinolinic Acid in Primary Human Neurons. Mol Neurobiol 2020; 58:34-54. [PMID: 32894500 DOI: 10.1007/s12035-020-02046-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/28/2020] [Indexed: 01/18/2023]
Abstract
In Alzheimer's disease (AD), excessive amounts of quinolinic acid (QUIN) accumulate within the brain parenchyma and dystrophic neurons. QUIN also regulates glutamate uptake into neurons, which may be due to modulation of Na+-dependent excitatory amino acid transporters (EAATs). To determine the biological relationships between QUIN and glutamate dysfunction, we first quantified the functionality and kinetics of [3H]QUIN uptake in primary human neurons using liquid scintillation. We then measured changes in the protein expression of the glutamate transporter EAAT3 and EAAT1b in primary neurons treated with QUIN and the EAAT inhibitor L-trans-pyrrolidine-2,4-dicarboxylic acid (2,4-PDC) using western blotting and immunohistochemistry. Immunohistochemistry was further used to elucidate intracellular transport of exogenous QUIN and the lysosomal-associated membrane protein 2 (LAMP2). Structural insights into the binding between QUIN and EAAT3 were further investigated using molecular docking techniques. We report significant temperature-dependent high-affinity transport leading to neuronal uptake of [3H]QUIN with a Km of 42.2 μM, and a Vmax of 9.492 pmol/2 min/mg protein, comparable with the uptake of glutamate. We also found that QUIN increases expression of the EAAT3 monomer while decreasing the functional trimer. QUIN uptake into primary neurons was shown to involve EAAT3 as uptake was significantly attenuated following EAAT inhibition. We also demonstrated that QUIN increases the expression of aberrant EAAT1b protein in neurons further implicating QUIN-induced glutamate dysfunction. Furthermore, we demonstrated that QUIN is metabolised exclusively in lysosomes. The involvement of EAAT3 as a modulator for QUIN uptake was further confirmed using molecular docking. This study is the first to characterise a mechanism for QUIN uptake into primary human neurons involving EAAT3, opening potential targets to attenuate QUIN-induced excitotoxicity in neuroinflammatory diseases.
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Affiliation(s)
- Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia.
- School of Medicine, Huzhou University, Wuxing District, Huzhou, Zhejiang, China.
| | - Hayden Alicajic
- Neuropharmacology group, MND and Neurodegenerative diseases Research Centre, Macquarie University, Sydney, NSW, 2019, Australia
| | - David Pow
- University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jason Smith
- Department of Chemistry and Biomolecular sciences, Macquarie University, Sydney, NSW, Australia
| | - Bat-Erdene Jugder
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Bruce J Brew
- St Vincent's Centre for Applied Medical Research, Sydney, Australia
- Department of Neurology and HIV Medicine, St Vincent's Hospital, Sydney, Australia
| | - Joseph A Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - Gilles J Guillemin
- Neuropharmacology group, MND and Neurodegenerative diseases Research Centre, Macquarie University, Sydney, NSW, 2019, Australia.
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22
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Long-Term Impact of Early-Life Stress on Hippocampal Plasticity: Spotlight on Astrocytes. Int J Mol Sci 2020; 21:ijms21144999. [PMID: 32679826 PMCID: PMC7404101 DOI: 10.3390/ijms21144999] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022] Open
Abstract
Adverse experiences during childhood are among the most prominent risk factors for developing mood and anxiety disorders later in life. Early-life stress interventions have been established as suitable models to study the neurobiological basis of childhood adversity in rodents. Different models such as maternal separation, impaired maternal care and juvenile stress during the postweaning/prepubertal life phase are utilized. Especially within the limbic system, they induce lasting alterations in neuronal circuits, neurotransmitter systems, neuronal architecture and plasticity that are further associated with emotional and cognitive information processing. Recent studies found that astrocytes, a special group of glial cells, have altered functions following early-life stress as well. As part of the tripartite synapse, astrocytes interact with neurons in multiple ways by affecting neurotransmitter uptake and metabolism, by providing gliotransmitters and by providing energy to neurons within local circuits. Thus, astrocytes comprise powerful modulators of neuronal plasticity and are well suited to mediate the long-term effects of early-life stress on neuronal circuits. In this review, we will summarize current findings on altered astrocyte function and hippocampal plasticity following early-life stress. Highlighting studies for astrocyte-related plasticity modulation as well as open questions, we will elucidate the potential of astrocytes as new targets for interventions against stress-induced neuropsychiatric disorders.
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23
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Caruso G, Spampinato SF, Cardaci V, Caraci F, Sortino MA, Merlo S. β-amyloid and Oxidative Stress: Perspectives in Drug Development. Curr Pharm Des 2020; 25:4771-4781. [PMID: 31814548 DOI: 10.2174/1381612825666191209115431] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 12/04/2019] [Indexed: 01/08/2023]
Abstract
Alzheimer's Disease (AD) is a slow-developing neurodegenerative disorder in which the main pathogenic role has been assigned to β-amyloid protein (Aβ) that accumulates in extracellular plaques. The mechanism of action of Aβ has been deeply analyzed and several membrane structures have been identified as potential mediators of its effect. The ability of Aβ to modify neuronal activity, receptor expression, signaling pathways, mitochondrial function, and involvement of glial cells have been analyzed. In addition, extensive literature deals with the involvement of oxidative stress in Aβ effects. Herein we focus more specifically on the reciprocal regulation of Aβ, that causes oxidative stress, that favors Aβ aggregation and toxicity and negatively affects the peptide clearance. Analysis of this strict interaction may offer novel opportunities for therapeutic intervention. Both common and new molecules endowed with antioxidant properties deserve attention in this regard.
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Affiliation(s)
| | - Simona F Spampinato
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95125 Catania, Italy
| | - Vincenzo Cardaci
- Scuola Superiore di Catania, University of Catania, 95123 Catania, Italy.,Department of Drug Sciences, University of Catania, 95125 Catania, Italy
| | - Filippo Caraci
- Oasi Research Institute - IRCCS, 94018 Troina, Italy.,Department of Drug Sciences, University of Catania, 95125 Catania, Italy
| | - Maria A Sortino
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95125 Catania, Italy
| | - Sara Merlo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, 95125 Catania, Italy
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24
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Conway ME. Alzheimer's disease: targeting the glutamatergic system. Biogerontology 2020; 21:257-274. [PMID: 32048098 PMCID: PMC7196085 DOI: 10.1007/s10522-020-09860-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/29/2020] [Indexed: 12/21/2022]
Abstract
Alzheimer’s disease (AD) is a debilitating neurodegenerative disease that causes a progressive decline in memory, language and problem solving. For decades mechanism-based therapies have primarily focused on amyloid β (Aβ) processing and pathways that govern neurofibrillary tangle generation. With the potential exception to Aducanumab, a monotherapy to target Aβ, clinical trials in these areas have been challenging and have failed to demonstrate efficacy. Currently, the prescribed therapies for AD are those that target the cholinesterase and glutamatergic systems that can moderately reduce cognitive decline, dependent on the individual. In the brain, over 40% of neuronal synapses are glutamatergic, where the glutamate level is tightly regulated through metabolite exchange in neuronal, astrocytic and endothelial cells. In AD brain, Aβ can interrupt effective glutamate uptake by astrocytes, which evokes a cascade of events that leads to neuronal swelling, destruction of membrane integrity and ultimately cell death. Much work has focussed on the post-synaptic response with little insight into how glutamate is regulated more broadly in the brain and the influence of anaplerotic pathways that finely tune these mechanisms. The role of blood branched chain amino acids (BCAA) in regulating neurotransmitter profiles under disease conditions also warrant discussion. Here, we review the importance of the branched chain aminotransferase proteins in regulating brain glutamate and the potential consequence of dysregulated metabolism in the context of BCAA or glutamate accumulation. We explore how the reported benefits of BCAA supplementation or restriction in improving cognitive function in other neurological diseases may have potential application in AD. Given that memantine, the glutamate receptor agonist, shows clinical relevance it is now timely to research related pathways, an understanding of which could identify novel approaches to treatment of AD.
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Affiliation(s)
- Myra E Conway
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK. .,Faculty of Health and Life Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK.
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25
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Amyloid Fibril-Induced Astrocytic Glutamate Transporter Disruption Contributes to Complement C1q-Mediated Microglial Pruning of Glutamatergic Synapses. Mol Neurobiol 2020; 57:2290-2300. [PMID: 32008166 DOI: 10.1007/s12035-020-01885-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/21/2020] [Indexed: 01/23/2023]
Abstract
The complement C1q plays a critical role in microglial phagocytosis of glutamatergic synapses and in the pathogenesis of neuroinflammation in Alzheimer's disease (AD). We recently reported that upregulation of metabotropic glutamate receptor signaling is associated with increased synaptic C1q production and subsequent microglial phagocytosis of synapses in the rodent models of AD. Here, we explored the role of astrocytic glutamate transporter in the synaptic C1q production and microglial phagocytosis of hippocampal glutamatergic synapses in a rat model of AD. Activation of astrocyte and reduction glutamate transporter 1 (GLT1) were noted after bilateral microinjection of amyloid-beta (Aβ1-40) fibrils into the hippocampal CA1 area of rats. Ceftriaxone is a β-lactam antibiotic that upregulates GLT1 expression. Bilateral microinjection of ceftriaxone recovered GLT1 expression, decreased synaptic C1q production, suppressed microglial phagocytosis of glutamatergic synapses in the hippocampal CA1, and attenuated synaptic and cognitive deficits in rats microinjected with Aβ1-40. In contrast, artificial suppression of GLT1 activity by DL-threo-beta-benzyloxyaspartate (DL-TBOA) in naïve rats induced synaptic C1q expression and microglial phagocytosis of glutamatergic synapses in the hippocampal CA1 area, resulting in synaptic and cognitive dysfunction. These findings demonstrated that impairment of astrocytic glutamate transporter plays a role in the pathogenesis of AD.
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26
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Malik AR, Willnow TE. Excitatory Amino Acid Transporters in Physiology and Disorders of the Central Nervous System. Int J Mol Sci 2019; 20:ijms20225671. [PMID: 31726793 PMCID: PMC6888459 DOI: 10.3390/ijms20225671] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Excitatory amino acid transporters (EAATs) encompass a class of five transporters with distinct expression in neurons and glia of the central nervous system (CNS). EAATs are mainly recognized for their role in uptake of the amino acid glutamate, the major excitatory neurotransmitter. EAATs-mediated clearance of glutamate released by neurons is vital to maintain proper glutamatergic signalling and to prevent toxic accumulation of this amino acid in the extracellular space. In addition, some EAATs also act as chloride channels or mediate the uptake of cysteine, required to produce the reactive oxygen speciesscavenger glutathione. Given their central role in glutamate homeostasis in the brain, as well as their additional activities, it comes as no surprise that EAAT dysfunctions have been implicated in numerous acute or chronic diseases of the CNS, including ischemic stroke and epilepsy, cerebellar ataxias, amyotrophic lateral sclerosis, Alzheimer’s disease and Huntington’s disease. Here we review the studies in cellular and animal models, as well as in humans that highlight the roles of EAATs in the pathogenesis of these devastating disorders. We also discuss the mechanisms regulating EAATs expression and intracellular trafficking and new exciting possibilities to modulate EAATs and to provide neuroprotection in course of pathologies affecting the CNS.
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Affiliation(s)
- Anna R. Malik
- Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
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27
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Cline EN, Bicca MA, Viola KL, Klein WL. The Amyloid-β Oligomer Hypothesis: Beginning of the Third Decade. J Alzheimers Dis 2019; 64:S567-S610. [PMID: 29843241 PMCID: PMC6004937 DOI: 10.3233/jad-179941] [Citation(s) in RCA: 520] [Impact Index Per Article: 104.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The amyloid-β oligomer (AβO) hypothesis was introduced in 1998. It proposed that the brain damage leading to Alzheimer’s disease (AD) was instigated by soluble, ligand-like AβOs. This hypothesis was based on the discovery that fibril-free synthetic preparations of AβOs were potent CNS neurotoxins that rapidly inhibited long-term potentiation and, with time, caused selective nerve cell death (Lambert et al., 1998). The mechanism was attributed to disrupted signaling involving the tyrosine-protein kinase Fyn, mediated by an unknown toxin receptor. Over 4,000 articles concerning AβOs have been published since then, including more than 400 reviews. AβOs have been shown to accumulate in an AD-dependent manner in human and animal model brain tissue and, experimentally, to impair learning and memory and instigate major facets of AD neuropathology, including tau pathology, synapse deterioration and loss, inflammation, and oxidative damage. As reviewed by Hayden and Teplow in 2013, the AβO hypothesis “has all but supplanted the amyloid cascade.” Despite the emerging understanding of the role played by AβOs in AD pathogenesis, AβOs have not yet received the clinical attention given to amyloid plaques, which have been at the core of major attempts at therapeutics and diagnostics but are no longer regarded as the most pathogenic form of Aβ. However, if the momentum of AβO research continues, particularly efforts to elucidate key aspects of structure, a clear path to a successful disease modifying therapy can be envisioned. Ensuring that lessons learned from recent, late-stage clinical failures are applied appropriately throughout therapeutic development will further enable the likelihood of a successful therapy in the near-term.
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Affiliation(s)
- Erika N Cline
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Maíra Assunção Bicca
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Kirsten L Viola
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - William L Klein
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
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28
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Carter SF, Herholz K, Rosa-Neto P, Pellerin L, Nordberg A, Zimmer ER. Astrocyte Biomarkers in Alzheimer's Disease. Trends Mol Med 2019; 25:77-95. [PMID: 30611668 DOI: 10.1016/j.molmed.2018.11.006] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 01/01/2023]
Abstract
Astrocytic contributions to Alzheimer's disease (AD) progression were, until recently, largely overlooked. Astrocytes are integral to normal brain function and astrocyte reactivity is an early feature of AD, potentially providing a promising target for preclinical diagnosis and treatment. Several in vivo AD biomarkers already exist, but presently there is a paucity of specific and sensitive in vivo astrocyte biomarkers that can accurately measure preclinical AD. Measuring monoamine oxidase-B with neuroimaging and glial fibrillary acidic protein from bodily fluids are biomarkers that are currently available. Developing novel, more specific, and sensitive astrocyte biomarkers will make it possible to pharmaceutically target chemical pathways that preserve beneficial astrocytic functions in response to AD pathology. This review discusses astrocyte biomarkers in the context of AD.
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Affiliation(s)
- Stephen F Carter
- Wolfson Molecular Imaging Centre, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
| | - Karl Herholz
- Wolfson Molecular Imaging Centre, Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, McGill Centre for Studies in Aging, McGill University, Montreal, Canada; Douglas Hospital Research Centre, Montreal, Canada; Montreal Neurological Institute, Montreal, Canada
| | - Luc Pellerin
- Département de Physiologie, Université de Lausanne, Lausanne, Switzerland; Centre de Résonance Magnétique des Systèmes Biologiques, UMR5536 CNRS, LabEx TRAIL-IBIO, Université de Bordeaux, Bordeaux Cedex 33760, France
| | - Agneta Nordberg
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Stockholm, Sweden; Theme Aging, Karolinska University Hospital, Huddinge, Sweden
| | - Eduardo R Zimmer
- Department of Pharmacology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Graduate Program in Biological Sciences: Pharmacology and Therapeutics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Brain Institute (BraIns) of Rio Grande do Sul, Porto Alegre, Brazil; Website: www.zimmer-lab.org.
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29
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Susceptibility to Aβo and TBOA of LTD and Extrasynaptic NMDAR-Dependent Tonic Current in the Aged Rat Hippocampus. Neurochem Res 2018; 44:692-702. [PMID: 30426348 DOI: 10.1007/s11064-018-2677-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/29/2022]
Abstract
Aging, as the major risk factor of Alzheimer's disease (AD), may increase susceptibility to neurodegenerative diseases through many gradual molecular and biochemical changes. Extracellular glutamate homeostasis and extrasynaptic glutamate N-methyl-D-aspartate receptors (NMDAR) are among early synaptic targets of oligomeric amyloid β (Aβo), one of the AD related synaptotoxic protein species. In this study, we asked for the effects of Aβo on long-term depression (LTD), a form of synaptic plasticity dependent on extrasynaptic NMDAR activation, and on a tonic current (TC) resulting from the activation of extrasynaptic NMDAR by ambient glutamate in hippocampal slices from young (3-6-month-old) and aged (24-28-month-old) Sprague-Dawley rats. Aβo significantly enhanced the magnitude of LTD and the amplitude of TC in aged slices compared to young ones. TBOA, a glutamate transporter inhibitor, also significantly increased LTD magnitude and TC amplitude in slices from aged rats, suggesting either an age-related weakness of the glutamate clearance system and/or a facilitated extrasynaptic NMDAR activation. From our present data, we hypothesize that senescence-related impairment of the extrasynaptic environment may be a vector of vulnerability of the aged hippocampus to neurodegenerative promotors such as Aβo.
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30
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Zhan X, Li F, Chu Q, Pang H. Secretogranin III may be an indicator of paraquat-induced astrocyte activation and affects the recruitment of BDNF during this process. Int J Mol Med 2018; 42:3622-3630. [PMID: 30280190 DOI: 10.3892/ijmm.2018.3909] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/28/2018] [Indexed: 11/06/2022] Open
Abstract
Astrocyte activation has been described as a multi‑stage defensive response, which is characterized by the morphological alteration of astrocytes and the overexpression of intermediate filament proteins. However, the functional mechanism of the secretion system in activated astroglia remains unclear. It has previously been demonstrated that secretogranin II, a member of the granin family, may be involved in the sorting and expression of inflammatory factors and excitatory neurotransmitters in paraquat (PQ)‑induced astroglial activation. Secretogranin III (SCG3) has been reported to represent an important component of the regulated secretory pathway in neuroendocrine cells; however, its role as an anchor protein of dense‑core vesicles in astrocytes remains to be elucidated. In the present study, a PQ‑activated U118MG astrocytoma cell model established in our previous study was used to investigate the effects of SCG3. The results revealed that SCG3 was highly expressed and subsequently released from cells in response to PQ. Inhibition of SCG3 expression via transfection with small interfering RNA partially restored astrocyte morphology, but did not affect the expression of astrocytic factors. Further studies investigating the association between SCG3 and other cellular factors were conducted, in order to determine the expression levels and subcellular localization of these proteins. Neurotrophins and inflammatory factors exhibited an increase in characteristic expression patterns, paralleling the alterations in SCG3 expression. The results further demonstrated that brain‑derived neurotrophic factor partially colocalized with SCG3‑positive vesicles; however, the localization of interleukin‑6 was not affected. In conclusion, SCG3 may be involved in PQ‑induced astrocyte activation via regulation of the expression and selective recruitment of cellular factors, thus suggesting that SCG3 may represent an indicator of astrocyte activation.
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Affiliation(s)
- Xiaoni Zhan
- Department of Forensic Genetics and Biology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
| | - Fengrui Li
- Department of Forensic Medicine, Baotou Medical College, Baotou, Inner Mongolia 014040, P.R. China
| | - Qiaohong Chu
- Precision Medicine and Healthcare Center, Qingdao Binhai University, Qingdao, Shandong 266555, P.R. China
| | - Hao Pang
- Department of Forensic Genetics and Biology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning 110122, P.R. China
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31
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Delgado JY, Fink AE, Grant SGN, O'Dell TJ, Opazo P. Rapid homeostatic downregulation of LTP by extrasynaptic GluN2B receptors. J Neurophysiol 2018; 120:2351-2357. [PMID: 30110236 PMCID: PMC6295522 DOI: 10.1152/jn.00421.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although the activation of extrasynaptic GluN2B-containing N-methyl-d-aspartate (NMDA) receptors has been implicated in neurodegenerative diseases, such as Alzheimer’s and Huntington’s disease, their physiological function remains unknown. In this study, we found that extrasynaptic GluN2B receptors play a homeostatic role by antagonizing long-term potentiation (LTP) induction under conditions of prolonged synaptic stimulation. In particular, we have previously found that brief theta-pulse stimulation (5 Hz for 30 s) triggers robust LTP, whereas longer stimulation times (5 Hz for 3 min) have no effect on basal synaptic transmission in the hippocampal CA1 region. Here, we show that prolonged stimulation blocked LTP by activating extrasynaptic GluN2B receptors via glutamate spillover. In addition, we found that this homeostatic mechanism was absent in slices from the SAP102 knockout, providing evidence for a functional coupling between extrasynaptic GluN2B and the SAP102 scaffold protein. In conclusion, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction via the activation of extrasynaptic GluN2B-containing NMDA receptors. NEW & NOTEWORTHY Although long-term potentiation (LTP) is an attractive model for memory storage, it tends to destabilize neuronal circuits because it drives synapses toward a maximum value. Unless opposed by homeostatic mechanisms operating through negative feedback rules, cumulative LTP could render synapses unable to encode additional information. In this study, we uncovered a rapid homeostatic mechanism that antagonizes LTP induction under conditions of prolonged synaptic stimulation via the activation of an extrasynaptic GluN2B-SAP102 complex.
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Affiliation(s)
- Jary Y Delgado
- Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Ann E Fink
- Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Seth G N Grant
- Genes to Cognition Programme, Centre for Clinical Brain Science, Edinburgh University , Edinburgh , United Kingdom
| | - Thomas J O'Dell
- Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Patricio Opazo
- Department of Physiology, University of California, Los Angeles, Los Angeles, California
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32
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Pál B. Involvement of extrasynaptic glutamate in physiological and pathophysiological changes of neuronal excitability. Cell Mol Life Sci 2018; 75:2917-2949. [PMID: 29766217 PMCID: PMC11105518 DOI: 10.1007/s00018-018-2837-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Glutamate is the most abundant neurotransmitter of the central nervous system, as the majority of neurons use glutamate as neurotransmitter. It is also well known that this neurotransmitter is not restricted to synaptic clefts, but found in the extrasynaptic regions as ambient glutamate. Extrasynaptic glutamate originates from spillover of synaptic release, as well as from astrocytes and microglia. Its concentration is magnitudes lower than in the synaptic cleft, but receptors responding to it have higher affinity for it. Extrasynaptic glutamate receptors can be found in neuronal somatodendritic location, on astroglia, oligodendrocytes or microglia. Activation of them leads to changes of neuronal excitability with different amplitude and kinetics. Extrasynaptic glutamate is taken up by neurons and astrocytes mostly via EAAT transporters, and astrocytes, in turn metabolize it to glutamine. Extrasynaptic glutamate is involved in several physiological phenomena of the central nervous system. It regulates neuronal excitability and synaptic strength by involving astroglia; contributing to learning and memory formation, neurosecretory and neuromodulatory mechanisms, as well as sleep homeostasis.The extrasynaptic glutamatergic system is affected in several brain pathologies related to excitotoxicity, neurodegeneration or neuroinflammation. Being present in dementias, neurodegenerative and neuropsychiatric diseases or tumor invasion in a seemingly uniform way, the system possibly provides a common component of their pathogenesis. Although parts of the system are extensively discussed by several recent reviews, in this review I attempt to summarize physiological actions of the extrasynaptic glutamate on neuronal excitability and provide a brief insight to its pathology for basic understanding of the topic.
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Affiliation(s)
- Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, Debrecen, 4012, Hungary.
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33
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Benarroch EE. Glutamatergic synaptic plasticity and dysfunction in Alzheimer disease. Neurology 2018; 91:125-132. [DOI: 10.1212/wnl.0000000000005807] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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