51
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Modified Glutamatergic Postsynapse in Neurodegenerative Disorders. Neuroscience 2019; 454:116-139. [PMID: 31887357 DOI: 10.1016/j.neuroscience.2019.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/02/2019] [Accepted: 12/02/2019] [Indexed: 01/27/2023]
Abstract
The postsynaptic density (PSD) is a complex subcellular domain important for postsynaptic signaling, function, and plasticity. The PSD is present at excitatory synapses and specialized to allow for precise neuron-to-neuron transmission of information. The PSD is localized immediately underneath the postsynaptic membrane forming a major protein network that regulates postsynaptic signaling and synaptic plasticity. Glutamatergic synaptic dysfunction affecting PSD morphology and signaling events have been described in many neurodegenerative disorders, either sporadic or familial forms. Thus, in this review we describe the main protein players forming the PSD and their activity, as well as relevant modifications in key components of the postsynaptic architecture occurring in Huntington's, Parkinson's and Alzheimer's diseases.
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Faldini E, Ahmed T, Bueé L, Blum D, Balschun D. Tau- but not Aß -pathology enhances NMDAR-dependent depotentiation in AD-mouse models. Acta Neuropathol Commun 2019; 7:202. [PMID: 31815648 PMCID: PMC6902514 DOI: 10.1186/s40478-019-0813-4] [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: 07/25/2019] [Accepted: 09/22/2019] [Indexed: 11/10/2022] Open
Abstract
Many mouse models of Alzheimer's disease (AD) exhibit impairments in hippocampal long-term-potentiation (LTP), seemingly corroborating the strong correlation between synaptic loss and cognitive decline reported in human studies. In other AD mouse models LTP is unaffected, but other defects in synaptic plasticity may still be present. We recently reported that THY-Tau22 transgenic mice, that overexpress human Tau protein carrying P301S and G272 V mutations and show normal LTP upon high-frequency-stimulation (HFS), develop severe changes in NMDAR mediated long-term-depression (LTD), the physiological counterpart of LTP. In the present study, we focused on putative effects of AD-related pathologies on depotentiation (DP), another form of synaptic plasticity. Using a novel protocol to induce DP in the CA1-region, we found in 11-15 months old male THY-Tau22 and APPPS1-21 transgenic mice that DP was not deteriorated by Aß pathology while significantly compromised by Tau pathology. Our findings advocate DP as a complementary form of synaptic plasticity that may help in elucidating synaptic pathomechanisms associated with different types of dementia.
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53
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Stefaniak E, Bal W. Cu II Binding Properties of N-Truncated Aβ Peptides: In Search of Biological Function. Inorg Chem 2019; 58:13561-13577. [PMID: 31304745 DOI: 10.1021/acs.inorgchem.9b01399] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
As life expectancy increases, the number of people affected by progressive and irreversible dementia, Alzheimer's Disease (AD), is predicted to grow. No drug designs seem to be working in humans, apparently because the origins of AD have not been identified. Invoking amyloid cascade, metal ions, and ROS production hypothesis of AD, herein we share our point of view on Cu(II) binding properties of Aβ4-x, the most prevalent N-truncated Aβ peptide, currently known as the main constituent of amyloid plaques. The capability of Aβ4-x to rapidly take over copper from previously tested Aβ1-x peptides and form highly stable complexes, redox unreactive and resistant to copper exchange reactions, prompted us to propose physiological roles for these peptides. We discuss the new findings on the reactivity of Cu(II)Aβ4-x with coexisting biomolecules in the context of synaptic cleft; we suggest that the role of Aβ4-x peptides is to quench Cu(II) toxicity in the brain and maintain neurotransmission.
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Affiliation(s)
- Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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54
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Lesuis SL, Lucassen PJ, Krugers HJ. Early life stress amplifies fear responses and hippocampal synaptic potentiation in the APPswe/PS1dE9 Alzheimer mouse model. Neuroscience 2019; 454:151-161. [PMID: 31302265 DOI: 10.1016/j.neuroscience.2019.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/25/2019] [Accepted: 07/02/2019] [Indexed: 01/04/2023]
Abstract
Cognitive deficits and alterations in emotional behaviour are typical features of Alzheimer's disease (AD). Moreover, exposure to stress or adversity during the early life period has been associated with an acceleration of cognitive deficits and increased AD pathology in transgenic AD mouse models. Whether and how early life adversity affects fear memory in AD mice remains elusive. We therefore investigated whether exposure to early life stress (ELS) alters fear learning in APPswe/PS1dE9 mice, a classic mouse model for AD, and whether this is accompanied by alterations in hippocampal synaptic potentiation, an important cellular substrate for learning and memory. Transgenic APPswe/PS1dE9 mice were subjected to ELS by housing the dams and her pups with limited nesting and bedding material from postnatal days 2-9. Following a fear conditioning paradigm, 12-month-old ELS-exposed APPswe/PS1dE9 mice displayed enhanced contextual freezing behaviour, both in the conditioning context and in a novel context. ELS-exposed APPswe/PS1dE9 mice also displayed enhanced hippocampal synaptic potentiation, even in the presence of the GluN2B antagonist Ro25-6981 (which prevented synaptic potentiation in control mice). No differences in the level of PSD-95 or synaptophysin were observed between the groups. We conclude that in APPswe/PS1dE9 mice, ELS increases fear memory in the conditioning context as well as a novel context, which is accompanied by aberrant hippocampal synaptic potentiation. These results may help to understand how individual differences in the vulnerability to develop AD arise and emphasise the importance of the early postnatal time window in these differences. This article is part of Special Issue entitled: Lifestyle and Brain Metaplasticity.
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Affiliation(s)
- Sylvie L Lesuis
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, the Netherlands.
| | - Paul J Lucassen
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, the Netherlands
| | - Harm J Krugers
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, the Netherlands
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55
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Afonso P, De Luca P, Carvalho RS, Cortes L, Pinheiro P, Oliveiros B, Almeida RD, Mele M, Duarte CB. BDNF increases synaptic NMDA receptor abundance by enhancing the local translation of Pyk2 in cultured hippocampal neurons. Sci Signal 2019; 12:12/586/eaav3577. [PMID: 31213568 DOI: 10.1126/scisignal.aav3577] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The effects of brain-derived neurotrophic factor (BDNF) in long-term synaptic potentiation (LTP) are thought to underlie learning and memory formation and are partly mediated by local protein synthesis. Here, we investigated the mechanisms that mediate BDNF-induced alterations in the synaptic proteome that are coupled to synaptic strengthening. BDNF induced the synaptic accumulation of GluN2B-containing NMDA receptors (NMDARs) and increased the amplitude of NMDAR-mediated miniature excitatory postsynaptic currents (mEPSCs) in cultured rat hippocampal neurons by a mechanism requiring activation of the protein tyrosine kinase Pyk2 and dependent on cellular protein synthesis. Single-particle tracking using quantum dot imaging revealed that the increase in the abundance of synaptic NMDAR currents correlated with their enhanced stability in the synaptic compartment. Furthermore, BDNF increased the local synthesis of Pyk2 at the synapse, and the observed increase in Pyk2 protein abundance along dendrites of cultured hippocampal neurons was mediated by a mechanism dependent on the ribonucleoprotein hnRNP K, which bound to Pyk2 mRNA and dissociated from it upon BDNF application. Knocking down hnRNP K reduced the BDNF-induced synaptic synthesis of Pyk2 protein, whereas its overexpression enhanced it. Together, these findings indicate that hnRNP K mediates the synaptic distribution of Pyk2 synthesis, and hence the synaptic incorporation of GluN2B-containing NMDARs, induced by BDNF, which may affect LTP and synaptic plasticity.
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Affiliation(s)
- Pedro Afonso
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Pasqualino De Luca
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Rafael S Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Luísa Cortes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Paulo Pinheiro
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Barbara Oliveiros
- Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.,Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ramiro D Almeida
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Health Sciences Program, Department of Medical Sciences, Institute of Biomedicine - iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Miranda Mele
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-790 Coimbra, Portugal
| | - Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal. .,Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
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56
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Metzbower SR, Joo Y, Benavides DR, Blanpied TA. Properties of Individual Hippocampal Synapses Influencing NMDA-Receptor Activation by Spontaneous Neurotransmission. eNeuro 2019; 6:ENEURO.0419-18.2019. [PMID: 31110134 PMCID: PMC6541874 DOI: 10.1523/eneuro.0419-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 05/05/2019] [Accepted: 05/12/2019] [Indexed: 12/14/2022] Open
Abstract
NMDA receptor (NMDAR) activation is critical for maintenance and modification of synapse strength. Specifically, NMDAR activation by spontaneous glutamate release has been shown to mediate some forms of synaptic plasticity as well as synaptic development. Interestingly, there is evidence that within individual synapses each release mode may be segregated such that postsynaptically there are distinct pools of responsive receptors. To examine potential regulators of NMDAR activation because of spontaneous glutamate release in cultured hippocampal neurons, we used GCaMP6f imaging at single synapses in concert with confocal and super-resolution imaging. Using these single-spine approaches, we found that Ca2+ entry activated by spontaneous release tends to be carried by GluN2B-NMDARs. Additionally, the amount of NMDAR activation varies greatly both between synapses and within synapses, and is unrelated to spine and synapse size, but does correlate loosely with synapse distance from the soma. Despite the critical role of spontaneous activation of NMDARs in maintaining synaptic function, their activation seems to be controlled factors other than synapse size or synapse distance from the soma. It is most likely that NMDAR activation by spontaneous release influenced variability in subsynaptic receptor position, release site position, vesicle content, and channel properties. Therefore, spontaneous activation of NMDARs appears to be regulated distinctly from other receptor types, notably AMPARs, within individual synapses.
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Affiliation(s)
| | - Yuyoung Joo
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - David R Benavides
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
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57
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Nazarian A, Arbeev KG, Yashkin AP, Kulminski AM. Genetic heterogeneity of Alzheimer's disease in subjects with and without hypertension. GeroScience 2019; 41:137-154. [PMID: 31055733 PMCID: PMC6544706 DOI: 10.1007/s11357-019-00071-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 04/25/2019] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder caused by the interplay of multiple genetic and non-genetic factors. Hypertension is one of the AD risk factors that has been linked to underlying pathological changes like senile plaques and neurofibrillary tangles formation as well as hippocampal atrophy. In this study, we investigated the differences in the genetic architecture of AD between hypertensive and non-hypertensive subjects in four independent cohorts. Our genome-wide association analyses revealed significant associations of 15 novel potentially AD-associated polymorphisms (P < 5E-06) that were located outside the chromosome 19q13 region and were significant either in hypertensive or non-hypertensive groups. The closest genes to 14 polymorphisms were not associated with AD at P < 5E-06 in previous genome-wide association studies (GWAS). Also, four of them were located within two chromosomal regions (i.e., 3q13.11 and 17q21.2) that were not associated with AD at P < 5E-06 before. In addition, 30 genes demonstrated evidence of group-specific associations with AD at the false discovery rates (FDR) < 0.05 in our gene-based and transcriptome-wide association analyses. The chromosomal regions corresponding to four genes (i.e., 2p13.1, 9p13.3, 17q12, and 18q21.1) were not associated with AD at P < 5E-06 in previous GWAS. These genes may serve as a list of prioritized candidates for future functional studies. Our pathway-enrichment analyses revealed the associations of 11 non-group-specific and four group-specific pathways with AD at FDR < 0.05. These findings provided novel insights into the potential genetic heterogeneity of AD among subjects with and without hypertension.
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Affiliation(s)
- Alireza Nazarian
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Erwin Mill Building, 2024 W. Main St., Durham, NC, 27705, USA.
| | - Konstantin G Arbeev
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Erwin Mill Building, 2024 W. Main St., Durham, NC, 27705, USA
| | - Arseniy P Yashkin
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Erwin Mill Building, 2024 W. Main St., Durham, NC, 27705, USA
| | - Alexander M Kulminski
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Erwin Mill Building, 2024 W. Main St., Durham, NC, 27705, USA.
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58
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Evans CE, Thomas RS, Freeman TJ, Hvoslef-Eide M, Good MA, Kidd EJ. Selective reduction of APP-BACE1 activity improves memory via NMDA-NR2B receptor-mediated mechanisms in aged PDAPP mice. Neurobiol Aging 2019; 75:136-149. [PMID: 30572184 PMCID: PMC6357873 DOI: 10.1016/j.neurobiolaging.2018.11.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 10/26/2018] [Accepted: 11/12/2018] [Indexed: 01/07/2023]
Abstract
β-Amyloid (Aβ) accumulation is an early event of Alzheimer's disease (AD) pathogenesis. Inhibition of Aβ production by β-secretase (BACE) has been proposed as a potential therapeutic strategy for AD. However, BACE inhibitors lack specificity and have had limited clinical benefit. To better study the consequences of reducing BACE metabolism, specifically of APP, we used an antibody, 2B3, that binds to APP at the BACE cleavage site, inhibiting Aβ production. 2B3 was administered either directly into the lateral ventricles or by intraperitoneal injection to (platelet-derived growth factor promoter hAPP717V (PDAPP) mice and WT mice. 2B3 reduced soluble Aβ40 and βCTF (β-amyloid derived C-terminal fragment) and improved memory for object-in-place associations and working memory in a foraging task in PDAPP mice. 2B3 also normalized the phosphorylation of the N-methyl-D-aspartate receptor NR2B subunit and subsequent extracellular signal-regulated kinase signaling. The importance of this NR2B pathway for OiP memory was confirmed by administering the NR2B antagonist, Ro25-6981, to 18-month-old WT. In contrast, 2B3 impaired associative recognition memory in young WT mice. These data provide novel insights into the mechanism by which selective modulation of APP metabolism by BACE influences synaptic and cognitive processes in both normal mice and aged APP transgenic mice.
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Affiliation(s)
- Charles E Evans
- School of Psychology Cardiff University, Cardiff, UK; School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | - Rhian S Thomas
- School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, UK; Department of Applied Sciences, University of the West of England, Bristol, UK
| | - Thomas J Freeman
- School of Psychology Cardiff University, Cardiff, UK; School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, UK
| | | | - Mark A Good
- School of Psychology Cardiff University, Cardiff, UK.
| | - Emma J Kidd
- School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, UK
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59
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Lesuis SL, Kaplick PM, Lucassen PJ, Krugers HJ. Treatment with the glutamate modulator riluzole prevents early life stress-induced cognitive deficits and impairments in synaptic plasticity in APPswe/PS1dE9 mice. Neuropharmacology 2019; 150:175-183. [PMID: 30794835 DOI: 10.1016/j.neuropharm.2019.02.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/14/2019] [Accepted: 02/16/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Environmental factors like stress affect age-related cognitive deficits and promote Alzheimer's disease (AD)-related pathology in mice. Excess glutamate has been proposed as a possible mediator underlying these effects in the hippocampus, a vulnerable brain region implicated in learning and memory. METHODS Here, we examined a) whether stress applied during a sensitive developmental period early in life affects later synaptic plasticity, learning and memory and plaque load in the APPswe/PS1dE9 mouse model for Alzheimer's disease and b) whether these effects could be rescued using long-term treatment with the glutamate modulator riluzole. RESULTS Our results demonstrate that ELS impairs synaptic plasticity in 6-month-old mice and increases plaque load in 12-month-old APPswe/PS1dE9 mice, while impairing flexible spatial learning in the Barnes maze at this age. Notably, spatial learning correlated well with hippocampal expression of the transporter EAAT2, which is important for extracellular glutamate uptake. The changes in LTP, plaque load and cognition after ELS were all prevented by riluzole treatment that started from post-weaning. CONCLUSION These results suggest that normalising glutamate signalling may be a viable therapeutic strategy for treating vulnerable individuals at risk of developing stress-aggravated AD, particularly in relation to adverse early life experiences.
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Affiliation(s)
- Sylvie L Lesuis
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Paul M Kaplick
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Paul J Lucassen
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Harm J Krugers
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
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60
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Liu J, Chang L, Song Y, Li H, Wu Y. The Role of NMDA Receptors in Alzheimer's Disease. Front Neurosci 2019; 13:43. [PMID: 30800052 PMCID: PMC6375899 DOI: 10.3389/fnins.2019.00043] [Citation(s) in RCA: 234] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/16/2019] [Indexed: 12/13/2022] Open
Abstract
In Alzheimer’s disease (AD), early synaptic dysfunction is associated with the increased oligomeric amyloid-beta peptide, which causes NMDAR-dependent synaptic depression and spine elimination. Memantine, low-affinity NMDAR channel blocker, has been used in the treatment of moderate to severe AD. However, clear evidence is still deficient in demonstrating the underlying mechanisms and a relationship between NMDARs dysfunction and AD. This review focuses on not only changes in expression of different NMDAR subunits, but also some unconventional modes of NMDAR action.
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Affiliation(s)
- Jinping Liu
- School of Medicine, Tsinghua University, Beijing, China
| | - Lirong Chang
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yizhi Song
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Hui Li
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yan Wu
- Department of Anatomy, Ministry of Science and Technology Laboratory of Brain Disorders, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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61
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Skowrońska K, Obara-Michlewska M, Zielińska M, Albrecht J. NMDA Receptors in Astrocytes: In Search for Roles in Neurotransmission and Astrocytic Homeostasis. Int J Mol Sci 2019; 20:ijms20020309. [PMID: 30646531 PMCID: PMC6358855 DOI: 10.3390/ijms20020309] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 12/15/2022] Open
Abstract
Studies of the last two decades have demonstrated the presence in astrocytic cell membranes of N-methyl-d-aspartate (NMDA) receptors (NMDARs), albeit their apparently low abundance makes demonstration of their presence and function more difficult than of other glutamate (Glu) receptor classes residing in astrocytes. Activation of astrocytic NMDARs directly in brain slices and in acutely isolated or cultured astrocytes evokes intracellular calcium increase, by mutually unexclusive ionotropic and metabotropic mechanisms. However, other than one report on the contribution of astrocyte-located NMDARs to astrocyte-dependent modulation of presynaptic strength in the hippocampus, there is no sound evidence for the significant role of astrocytic NMDARs in astrocytic-neuronal interaction in neurotransmission, as yet. Durable exposure of astrocytic and neuronal co-cultures to NMDA has been reported to upregulate astrocytic synthesis of glutathione, and in this way to increase the antioxidative capacity of neurons. On the other hand, overexposure to NMDA decreases, by an as yet unknown mechanism, the ability of cultured astrocytes to express glutamine synthetase (GS), aquaporin-4 (AQP4), and the inward rectifying potassium channel Kir4.1, the three astroglia-specific proteins critical for homeostatic function of astrocytes. The beneficial or detrimental effects of astrocytic NMDAR stimulation revealed in the in vitro studies remain to be proven in the in vivo setting.
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Affiliation(s)
- Katarzyna Skowrońska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Marta Obara-Michlewska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Magdalena Zielińska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Jan Albrecht
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
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62
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Minnella AM, Zhao JX, Jiang X, Jakobsen E, Lu F, Wu L, El-Benna J, Gray JA, Swanson RA. Excitotoxic superoxide production and neuronal death require both ionotropic and non-ionotropic NMDA receptor signaling. Sci Rep 2018; 8:17522. [PMID: 30504838 PMCID: PMC6269523 DOI: 10.1038/s41598-018-35725-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 11/07/2018] [Indexed: 12/12/2022] Open
Abstract
NMDA-type glutamate receptors (NMDAR) trigger superoxide production by neuronal NADPH oxidase-2 (NOX2), which if sustained leads to cell death. This process involves Ca2+ influx through NMDAR channels. By contrast, comparable Ca2+ influx by other routes does not induce NOX2 activation or cell death. This contrast has been attributed to site-specific effects of Ca2+ flux through NMDAR. Here we show instead that it stems from non-ionotropic signaling by NMDAR GluN2B subunits. To evaluate non-ionotropic effects, mouse cortical neurons were treated with NMDA together with 7-chlorokynurenate, L-689,560, or MK-801, which block Ca2+ influx through NMDAR channels but not NMDA binding. NMDA-induced superoxide formation was prevented by the channel blockers, restored by concurrent Ca2+ influx through ionomycin or voltage-gated calcium channels, and not induced by the Ca2+ influx in the absence of NMDAR ligand binding. Neurons expressing either GluN2B subunits or chimeric GluN2A/GluN2B C-terminus subunits exhibited NMDA-induced superoxide production, whereas neurons expressing chimeric GluN2B/GluN2A C-terminus subunits did not. Neuronal NOX2 activation requires phosphoinositide 3-kinase (PI3K), and NMDA binding to NMDAR increased PI3K association with NMDA GluN2B subunits independent of Ca2+ influx. These findings identify a non-ionotropic signaling pathway that links NMDAR to NOX2 activation through the C-terminus domain of GluN2B.
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Affiliation(s)
- Angela M Minnella
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94122, USA.,San Francisco Veterans Affairs Medical Center, San Francisco, CA, 94121, USA
| | - Jerry X Zhao
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94122, USA.,San Francisco Veterans Affairs Medical Center, San Francisco, CA, 94121, USA
| | - Xiangning Jiang
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Fuxin Lu
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Long Wu
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94122, USA.,San Francisco Veterans Affairs Medical Center, San Francisco, CA, 94121, USA
| | - Jamel El-Benna
- INSERM-U1149, CNRS-ERL8252, Centre de Recherche sur l'Inflammation, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Laboratoire d'Excellence Inflamex, Faculté de Médecine, Site Xavier Bichat, Paris, France
| | - John A Gray
- Center for Neuroscience and Department of Neurology, University of California Davis, Davis, CA, 95618, USA
| | - Raymond A Swanson
- Department of Neurology, University of California, San Francisco, San Francisco, CA, 94122, USA. .,San Francisco Veterans Affairs Medical Center, San Francisco, CA, 94121, USA.
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63
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Montes de Oca Balderas P. Flux-Independent NMDAR Signaling: Molecular Mediators, Cellular Functions, and Complexities. Int J Mol Sci 2018; 19:ijms19123800. [PMID: 30501045 PMCID: PMC6321296 DOI: 10.3390/ijms19123800] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/21/2022] Open
Abstract
The glutamate (Glu) N-methyl-d-aspartate (NMDA) receptor (NMDAR) plays a critical role in synaptic communication given mainly by its ionotropic function that permeates Ca2+. This in turn activates calmodulin that triggers CaMKII, MAPK, CREB, and PI3K pathways, among others. However, NMDAR signaling is more complex. In the last two decades several groups have shown that the NMDAR also elicits flux-independent signaling (f-iNMDARs). It has been demonstrated that agonist (Glu or NMDA) or co-agonist (Glycine or d-Serine) bindings initiate intracellular events, including conformational changes, exchange of molecular interactions, release of second messengers, and signal transduction, that result in different cellular events including endocytosis, LTD, cell death, and neuroprotection, among others. Interestingly, f-iNMDARs has also been observed in pathological conditions and non-neuronal cells. Here, the molecular and cellular events elicited by these flux-independent actions (non-canonical or metabotropic-like) of the NMDAR are reviewed. Considering the NMDAR complexity, it is possible that these flux-independent events have a more relevant role in intracellular signaling that has been disregarded for decades. Moreover, considering the wide expression and function of the NMDAR in non-neuronal cells and other tissues beyond the nervous system and some evolutionary traits, f-iNMDARs calls for a reconsideration of how we understand the biology of this complex receptor.
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Affiliation(s)
- Pavel Montes de Oca Balderas
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM. Av. Universidad 3000, C.U. Coyoacán, Ciudad de México. C.P. 04510, Mexico.
- Unidad de Neurobiología Dinámica, Departamento de Neuroquímica, INNN. Av. Insurgentes Sur #3877 Col. La Fama, Ciudad de México. C.P. 14269, Mexico.
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Müller MK, Jacobi E, Sakimura K, Malinow R, von Engelhardt J. NMDA receptors mediate synaptic depression, but not spine loss in the dentate gyrus of adult amyloid Beta (Aβ) overexpressing mice. Acta Neuropathol Commun 2018; 6:110. [PMID: 30352630 PMCID: PMC6198500 DOI: 10.1186/s40478-018-0611-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 09/29/2018] [Indexed: 11/25/2022] Open
Abstract
Amyloid beta (Aβ)-mediated synapse dysfunction and spine loss are considered to be early events in Alzheimer’s disease (AD) pathogenesis. N-methyl-D-aspartate receptors (NMDARs) have previously been suggested to play a role for Amyloid beta (Aβ) toxicity. Pharmacological block of NMDAR subunits in cultured neurons and mice suggested that NMDARs containing the GluN2B subunit are necessary for Aβ-mediated changes in synapse number and function in hippocampal neurons. Interestingly, NMDARs undergo a developmental switch from GluN2B- to GluN2A-containing receptors. This indicates different functional roles of NMDARs in young mice compared to older animals. In addition, the lack of pharmacological tools to efficiently dissect the role of NMDARs containing the different subunits complicates the interpretation of their specific role. In order to address this problem and to investigate the specific role for Aβ toxicity of the distinct NMDAR subunits in dentate gyrus granule cells of adult mice, we used conditional knockout mouse lines for the subunits GluN1, GluN2A and GluN2B. Aβ-mediated changes in synaptic function and neuronal anatomy were investigated in several-months old mice with virus-mediated overproduction of Aβ and in 1-year old 5xFAD mice. We found that all three NMDAR subunits contribute to the Aβ-mediated decrease in the number of functional synapses. However, NMDARs are not required for the spine number reduction in dentate gyrus granule cells after chronic Aβ-overproduction in 5xFAD mice. Furthermore, the amplitude of synaptic and extrasynaptic NMDAR-mediated currents was reduced in dentate gyrus granule of 5xFAD mice without changes in current kinetics, suggesting that a redistribution or change in subunit composition of NMDARs does not play a role in mediating Amyloid beta (Aβ) toxicity. Our study indicates that NMDARs are involved in AD pathogenesis by compromising synapse function but not by affecting neuron morphology.
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Zhang JJ, Haubrich J, Bernabo M, Finnie PS, Nader K. Limits on lability: Boundaries of reconsolidation and the relationship to metaplasticity. Neurobiol Learn Mem 2018; 154:78-86. [DOI: 10.1016/j.nlm.2018.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/08/2018] [Accepted: 02/19/2018] [Indexed: 02/07/2023]
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Lesuis SL, Hoeijmakers L, Korosi A, de Rooij SR, Swaab DF, Kessels HW, Lucassen PJ, Krugers HJ. Vulnerability and resilience to Alzheimer's disease: early life conditions modulate neuropathology and determine cognitive reserve. Alzheimers Res Ther 2018; 10:95. [PMID: 30227888 PMCID: PMC6145191 DOI: 10.1186/s13195-018-0422-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/15/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive neurodegenerative disorder with a high prevalence among the elderly and a huge personal and societal impact. Recent epidemiological studies have indicated that the incidence and age of onset of sporadic AD can be modified by lifestyle factors such as education, exercise, and (early) stress exposure. Early life adversity is known to promote cognitive decline at a later age and to accelerate aging, which are both primary risk factors for AD. In rodent models, exposure to 'negative' or 'positive' early life experiences was recently found to modulate various measures of AD neuropathology, such as amyloid-beta levels and cognition at later ages. Although there is emerging interest in understanding whether experiences during early postnatal life also modulate AD risk in humans, the mechanisms and possible substrates underlying these long-lasting effects remain elusive. METHODS We review literature and discuss the role of early life experiences in determining later age and AD-related processes from a brain and cognitive 'reserve' perspective. We focus on rodent studies and the identification of possible early determinants of later AD vulnerability or resilience in relation to early life adversity/enrichment. RESULTS Potential substrates and mediators of early life experiences that may influence the development of AD pathology and cognitive decline are: programming of the hypothalamic-pituitary-adrenal axis, priming of the neuroinflammatory response, dendritic and synaptic complexity and function, overall brain plasticity, and proteins such as early growth response protein 1 (EGR1), activity regulated cytoskeleton-associated protein (Arc), and repressor element-1 silencing transcription factor (REST). CONCLUSIONS We conclude from these rodent studies that the early postnatal period is an important and sensitive phase that influences the vulnerability to develop AD pathology. Yet translational studies are required to investigate whether early life experiences also modify AD development in human studies, and whether similar molecular mediators can be identified in the sensitivity to develop AD in humans.
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Affiliation(s)
- Sylvie L. Lesuis
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Lianne Hoeijmakers
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Aniko Korosi
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Susanne R. de Rooij
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
- Department of Clinical Epidemiology, Biostatistics & Bio informatics, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Dick F. Swaab
- The Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, KNAW, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Helmut W. Kessels
- The Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, KNAW, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
- Department of Cellular and Computational Neuroscience, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Paul J. Lucassen
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Harm J. Krugers
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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67
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Bouvier G, Larsen RS, Rodríguez-Moreno A, Paulsen O, Sjöström PJ. Towards resolving the presynaptic NMDA receptor debate. Curr Opin Neurobiol 2018; 51:1-7. [DOI: 10.1016/j.conb.2017.12.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/15/2017] [Accepted: 12/31/2017] [Indexed: 12/13/2022]
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Abstract
Dynamic modification of synaptic connectivity in response to sensory experience is a vital step in the refinement of brain circuits as they are established during development and modified during learning. In addition to the well-established role for new spine growth and stabilization in the experience-dependent plasticity of neural circuits, dendritic spine elimination has been linked to improvements in learning, and dysregulation of spine elimination has been associated with intellectual disability and behavioral impairment. Proper brain function requires a tightly regulated balance between spine formation and spine elimination. Although most studies have focused on the mechanisms of spine formation, considerable progress has been made recently in delineating the neural activity patterns and downstream molecular mechanisms that drive dendritic spine elimination. Here, we review the current state of knowledge concerning the signaling pathways that drive dendritic spine shrinkage and elimination in the cerebral cortex and we discuss their implication in neuropsychiatric and neurodegenerative disease.
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Affiliation(s)
- Ivar S Stein
- 1 Center for Neuroscience, University of California, Davis, CA, USA
| | - Karen Zito
- 1 Center for Neuroscience, University of California, Davis, CA, USA
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Abstract
Alzheimer's disease (AD) is a debilitating disease influencing a multitude of outcomes, including memory function. Recent work suggests that memory may be influenced by exercise ('memorcise'), even among those with AD. The present narrative review details (1) the underlying mechanisms of AD; (2) whether exercise has a protective effect in preventing AD; (3) the mechanisms through which exercise may help to prevent AD; (4) the mechanisms through which exercise may help attenuate the progression of AD severity among those with existing AD; (5) the effects and mechanisms through which exercise is associated with memory among those with existing AD; and (6) exercise recommendations for those with existing AD. Such an understanding will aid clinicians in their ability to use exercise as a potential behavioral strategy to help prevent and treat AD.
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Affiliation(s)
- Paul D Loprinzi
- a Physical Activity Epidemiology Laboratory, Exercise Psychology Laboratory, Department of Health, Exercise Science and Recreation Management , The University of Mississippi , University , MS , USA
| | - Emily Frith
- a Physical Activity Epidemiology Laboratory, Exercise Psychology Laboratory, Department of Health, Exercise Science and Recreation Management , The University of Mississippi , University , MS , USA
| | - Pamela Ponce
- a Physical Activity Epidemiology Laboratory, Exercise Psychology Laboratory, Department of Health, Exercise Science and Recreation Management , The University of Mississippi , University , MS , USA
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70
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Sumner IL, Edwards RA, Asuni AA, Teeling JL. Antibody Engineering for Optimized Immunotherapy in Alzheimer's Disease. Front Neurosci 2018; 12:254. [PMID: 29740272 PMCID: PMC5924811 DOI: 10.3389/fnins.2018.00254] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/03/2018] [Indexed: 12/17/2022] Open
Abstract
There are nearly 50 million people with Alzheimer's disease (AD) worldwide and currently no disease modifying treatment is available. AD is characterized by deposits of Amyloid-β (Aβ), neurofibrillary tangles, and neuroinflammation, and several drug discovery programmes studies have focussed on Aβ as therapeutic target. Active immunization and passive immunization against Aβ leads to the clearance of deposits in humans and transgenic mice expressing human Aβ but have failed to improve memory loss. This review will discuss the possible explanations for the lack of efficacy of Aβ immunotherapy, including the role of a pro-inflammatory response and subsequent vascular side effects, the binding site of therapeutic antibodies and the timing of the treatment. We further discuss how antibodies can be engineered for improved efficacy.
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Affiliation(s)
- Isabelle L Sumner
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ross A Edwards
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jessica L Teeling
- Biological Sciences, University of Southampton, Southampton, United Kingdom
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71
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Krania P, Dimou E, Bantouna M, Kouvaros S, Tsiamaki E, Papatheodoropoulos C, Sarantis K, Angelatou F. Adenosine A 2A receptors are required for glutamate mGluR5- and dopamine D1 receptor-evoked ERK1/2 phosphorylation in rat hippocampus: involvement of NMDA receptor. J Neurochem 2018; 145:217-231. [PMID: 29205377 DOI: 10.1111/jnc.14268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 10/11/2017] [Accepted: 11/24/2017] [Indexed: 12/17/2022]
Abstract
Interaction between mGluR5 and NMDA receptors (NMDAR) is vital for synaptic plasticity and cognition. We recently demonstrated that stimulation of mGluR5 enhances NMDAR responses in hippocampus by phosphorylating NR2B(Tyr1472) subunit, and this reaction was enabled by adenosine A2A receptors (A2A R) (J Neurochem, 135, 2015, 714). In this study, by using in vitro phosphorylation and western blot analysis in hippocampal slices of male Wistar rats, we show that mGluR5 stimulation or mGluR5/NMDARs co-stimulation synergistically activate ERK1/2 signaling leading to c-Fos expression. Interestingly, both reactions are under the permissive control of endogenous adenosine acting through A2A Rs. Moreover, mGluR5-mediated ERK1/2 phosphorylation depends on NMDAR, which however exhibits a metabotropic way of function, since no ion influx through its ion channel is required. Furthermore, our results demonstrate that mGluR5 and mGluR5/NMDAR-evoked ERK1/2 activation correlates well with the mGluR5/NMDAR-evoked NR2B(Tyr1472) phosphorylation, since both phenomena coincide temporally, are Src dependent, and are both enabled by A2A Rs. This indicates a functional involvement of NR2B(Tyr1472) phosphorylation in the ERK1/2 activation. Our biochemical results are supported by electrophysiological data showing that in CA1 region of hippocampus, the theta burst stimulation (TBS)-induced long-term potentiation coincides temporally with an increase in ERK1/2 activation and both phenomena are dependent on the tripartite A2A , mGlu5, and NMDARs. Furthermore, we show that the dopamine D1 receptors evoked ERK1/2 activation as well as the NR2B(Tyr1472) phosphorylation are also regulated by endogenous adenosine and A2A Rs. In conclusion, our results highlight the A2A Rs as a crucial regulator not only for NMDAR responses, but also for regulating ERK1/2 signaling and its downstream pathways, leading to gene expression, synaptic plasticity, and memory consolidation.
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Affiliation(s)
- Paraskevi Krania
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Eleni Dimou
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Maria Bantouna
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Stylianos Kouvaros
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Eirini Tsiamaki
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | | | | | - Fevronia Angelatou
- Physiology Department, Medical School, University of Patras, Patras, Greece
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Jurado S. AMPA Receptor Trafficking in Natural and Pathological Aging. Front Mol Neurosci 2018; 10:446. [PMID: 29375307 PMCID: PMC5767248 DOI: 10.3389/fnmol.2017.00446] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/21/2017] [Indexed: 01/09/2023] Open
Abstract
α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) enable most excitatory transmission in the brain and are crucial for mediating basal synaptic strength and plasticity. Because of the importance of their function, AMPAR dynamics, activity and subunit composition undergo a tight regulation which begins as early as prenatal development and continues through adulthood. Accumulating evidence suggests that the precise regulatory mechanisms involved in orchestrating AMPAR trafficking are challenged in the aging brain. In turn dysregulation of AMPARs can be linked to most neurological and neurodegenerative disorders. Understanding the mechanisms that govern AMPAR signaling during natural and pathological cognitive decline will guide the efforts to develop most effective ways to tackle neurodegenerative diseases which are one of the primary burdens afflicting an increasingly aging population. In this review, I provide a brief overview of the molecular mechanisms involved in AMPAR trafficking highlighting what is currently known about how these processes change with age and disease. As a particularly well-studied example of AMPAR dysfunction in pathological aging I focus in Alzheimer’s disease (AD) with special emphasis in how the production of neurofibrillary tangles (NFTs) and amyloid-β plaques may contribute to disruption in AMPAR function.
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Affiliation(s)
- Sandra Jurado
- Instituto de Neurociencias CSIC-UMH, San Juan de Alicante, Spain
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73
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Galliano E, Schonewille M, Peter S, Rutteman M, Houtman S, Jaarsma D, Hoebeek FE, De Zeeuw CI. Impact of NMDA Receptor Overexpression on Cerebellar Purkinje Cell Activity and Motor Learning. eNeuro 2018; 5:ENEURO.0270-17.2018. [PMID: 29464191 PMCID: PMC5815660 DOI: 10.1523/eneuro.0270-17.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/24/2017] [Accepted: 01/23/2018] [Indexed: 11/21/2022] Open
Abstract
In many brain regions involved in learning NMDA receptors (NMDARs) act as coincidence detectors of pre- and postsynaptic activity, mediating Hebbian plasticity. Intriguingly, the parallel fiber (PF) to Purkinje cell (PC) input in the cerebellar cortex, which is critical for procedural learning, shows virtually no postsynaptic NMDARs. Why is this? Here, we address this question by generating and testing independent transgenic lines that overexpress NMDAR containing the type 2B subunit (NR2B) specifically in PCs. PCs of the mice that show larger NMDA-mediated currents than controls at their PF input suffer from a blockage of long-term potentiation (LTP) at their PF-PC synapses, while long-term depression (LTD) and baseline transmission are unaffected. Moreover, introducing NMDA-mediated currents affects cerebellar learning in that phase-reversal of the vestibulo-ocular reflex (VOR) is impaired. Our results suggest that under physiological circumstances PC spines lack NMDARs postsynaptically at their PF input so as to allow LTP to contribute to motor learning.
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Affiliation(s)
- Elisa Galliano
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Martijn Schonewille
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Saša Peter
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Mandy Rutteman
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Simone Houtman
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Dick Jaarsma
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Freek E. Hoebeek
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Chris I. De Zeeuw
- Department of Neuroscience, Erasmus Medical Centre, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
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The RNA-Binding Protein hnRNP K Mediates the Effect of BDNF on Dendritic mRNA Metabolism and Regulates Synaptic NMDA Receptors in Hippocampal Neurons. eNeuro 2017; 4:eN-NWR-0268-17. [PMID: 29255796 PMCID: PMC5732018 DOI: 10.1523/eneuro.0268-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/25/2017] [Accepted: 11/09/2017] [Indexed: 11/21/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is an important mediator of long-term synaptic potentiation (LTP) in the hippocampus. The local effects of BDNF depend on the activation of translation activity, which requires the delivery of transcripts to the synapse. In this work, we found that neuronal activity regulates the dendritic localization of the RNA-binding protein heterogeneous nuclear ribonucleoprotein K (hnRNP K) in cultured rat hippocampal neurons by stimulating BDNF-Trk signaling. Microarray experiments identified a large number of transcripts that are coimmunoprecipitated with hnRNP K, and about 60% of these transcripts are dissociated from the protein upon stimulation of rat hippocampal neurons with BDNF. In vivo studies also showed a role for TrkB signaling in the dissociation of transcripts from hnRNP K upon high-frequency stimulation (HFS) of medial perforant path-granule cell synapses of male rat dentate gyrus (DG). Furthermore, treatment of rat hippocampal synaptoneurosomes with BDNF decreased the coimmunoprecipitation of hnRNP K with mRNAs coding for glutamate receptor subunits, Ca2+- and calmodulin-dependent protein kinase IIβ (CaMKIIβ) and BDNF. Downregulation of hnRNP K impaired the BDNF-induced enhancement of NMDA receptor (NMDAR)-mediated mEPSC, and similar results were obtained upon inhibition of protein synthesis with cycloheximide. The results demonstrate that BDNF regulates specific populations of hnRNP-associated mRNAs in neuronal dendrites and suggests an important role of hnRNP K in BDNF-dependent forms of synaptic plasticity.
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75
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Unconventional NMDA Receptor Signaling. J Neurosci 2017; 37:10800-10807. [PMID: 29118208 DOI: 10.1523/jneurosci.1825-17.2017] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Accepted: 09/28/2017] [Indexed: 11/21/2022] Open
Abstract
In the classical view, NMDA receptors (NMDARs) are stably expressed at the postsynaptic membrane, where they act via Ca2+ to signal coincidence detection in Hebbian plasticity. More recently, it has been established that NMDAR-mediated transmission can be dynamically regulated by neural activity. In addition, NMDARs have been found presynaptically, where they cannot act as conventional coincidence detectors. Unexpectedly, NMDARs have also been shown to signal metabotropically, without the need for Ca2+ This review highlights novel findings concerning these unconventional modes of NMDAR action.
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Lohman AW, Weilinger NL, Santos SM, Bialecki J, Werner AC, Anderson CL, Thompson RJ. Regulation of pannexin channels in the central nervous system by Src family kinases. Neurosci Lett 2017; 695:65-70. [PMID: 28911820 DOI: 10.1016/j.neulet.2017.09.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/24/2017] [Accepted: 09/10/2017] [Indexed: 02/06/2023]
Abstract
Pannexins form single membrane channels that regulate the passage of ions, small molecules and metabolites between the intra- and extracellular compartments. In the central nervous system, these channels are integrated into numerous signaling cascades that shape brain physiology and pathology. Post-translational modification of pannexins is complex, with phosphorylation emerging as a prominent form of functional regulation. While much is still not known regarding the specific kinases and modified amino acids, recent reports support a role for Src family tyrosine kinases (SFK) in regulating pannexin channel activity. This review outlines the current evidence supporting SFK-dependent pannexin phosphorylation in the CNS and examines the importance of these modifications in the healthy and diseased brain.
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Affiliation(s)
- Alexander W Lohman
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Nicholas L Weilinger
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Silva Mf Santos
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer Bialecki
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Allison C Werner
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Connor L Anderson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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Zhou R, Bickler P. Interaction of Isoflurane, Tumor Necrosis Factor-α and β-Amyloid on Long-term Potentiation in Rat Hippocampal Slices. Anesth Analg 2017; 124:582-587. [PMID: 28099324 DOI: 10.1213/ane.0000000000001698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The relationship between inhalational anesthetics such as isoflurane and cognitive impairment in the elderly is controversial. Both β-amyloid peptide (Aβ), associated with Alzheimer disease, and tumor necrosis factor-α (TNF-α), a proinflammatory stress-related peptide, impair the synaptic function. We hypothesized that transient exposure to isoflurane and these peptides would impair synaptic function, manifest as a depression of long-term potentiation (LTP) and paired pulse facilitation (PPF), in the rat hippocampus. METHODS Hippocampal slices were prepared from 3- to 4-week-old male Wistar rats. Preliminary experiments identified minimal concentrations of Aβ1-42 peptide and TNF-α that produced statistically detectable suppressing effects on LTP (600 nM Aβ1-42 and 5 ng/mL TNF-α). These concentrations of peptides were applied to slices alone, with 1.5% isoflurane, or in combination for 1 hour and then washed out. Measurements of LTP (field excitatory postsynaptic potentials [fEPSPs]) from neurons in the CA1 area by stimulation of the Schaffer-Collateral pathway were made after high-frequency stimulation (100 Hz, 1 second). Analysis of variance with correction for multiple comparisons was used to compare LTP under steady-state conditions and averaged for the 40- to 60-minute period after LTP induction. RESULTS EPSP amplitude after LTP induction was 155% ± 9% of baseline and was not affected by isoflurane exposure and washout (150% ± 4% of baseline, P = .47). Both Aβ1-42 and TNF-α reduced LTP by approximately 15% compared with control (129% ± 7% and 131% ± 11% of baseline respectively, means ± SD, both P < .001). When Aβ1-42 was combined with isoflurane, LTP was not impaired (151% ± 9% of control, P = .85), but isoflurane had no effect on LTP depression caused by TNF-α or a combination of Aβ and TNF-α. CONCLUSIONS Brief exposure to isoflurane prevents rather than impairs the decrease in LTP caused by Aβ1-42 in rat hippocampus. In contrast, isoflurane had no effect on synaptic impairment caused by TNF-α or a combination of TNF-α and Aβ. Although this is an in vitro study and translation to clinical medicine requires additional work, the interactions of isoflurane, Aβ, and TNF-α revealed here could have implications for patients with Alzheimer disease or perioperative neuroinflammation.
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Affiliation(s)
- Ran Zhou
- From the *Department of Anesthesia, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China; and †Department of Anesthesia and Perioperative Care, University of California San Francisco
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Valbuena S, Lerma J. Non-canonical Signaling, the Hidden Life of Ligand-Gated Ion Channels. Neuron 2017; 92:316-329. [PMID: 27764665 DOI: 10.1016/j.neuron.2016.10.016] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 12/25/2022]
Abstract
Neurotransmitter receptors are responsible for the transfer of information across the synapse. While ionotropic receptors form ion channels and mediate rapid membrane depolarization, so-called metabotropic receptors exert their action though slower, less direct intracellular signaling pathways. Glutamate, GABA, and acetylcholine can activate both ionotropic and metabotropic receptors, yet the distinction between these "canonical" signaling systems has become less clear since ionotropic receptors were proposed to also activate second messenger systems, defining a "non-canonical" signaling pathway. How these alternative pathways affect neuronal circuit activity is not well understood, and their influence could be more significant than previously anticipated. In this review, we examine the evidence available that supports the existence of parallel and unsuspected signaling pathways used by ionotropic neurotransmitter receptors.
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Affiliation(s)
- Sergio Valbuena
- Instituto de Neurociencias CSIC-UMH, 03550 San Juan de Alicante, Spain
| | - Juan Lerma
- Instituto de Neurociencias CSIC-UMH, 03550 San Juan de Alicante, Spain.
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79
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Local and Use-Dependent Effects of β-Amyloid Oligomers on NMDA Receptor Function Revealed by Optical Quantal Analysis. J Neurosci 2017; 36:11532-11543. [PMID: 27911757 DOI: 10.1523/jneurosci.1603-16.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/20/2016] [Accepted: 09/25/2016] [Indexed: 12/23/2022] Open
Abstract
Beta amyloid (Aβ) triggers the elimination of excitatory synaptic connections in the CNS, an early manifestation of Alzheimer's disease. Oligomeric assemblies of Aβ peptide associate with excitatory synapses resulting in synapse elimination through a process that requires NMDA-type glutamate receptor activation. Whether Aβ affects synaptic NMDA receptor (NMDAR) function directly and acts locally at synapses to which it has bound and whether synaptic activity influences Aβ synaptic binding and synaptotoxicity have remained fundamental questions. Here, we used subcellular Ca2+ imaging in rat hippocampal neurons to visualize NMDAR function at individual synapses before and after Aβ application. Aβ triggered a robust impairment of NMDAR Ca2+ entry at most, but not all, synapses. NMDAR function was more severely impaired at highly active synapses and synapses with bound Aβ, but activity was not required for Aβ synapse binding. Blocking NMDARs during Aβ exposure prevented Aβ-mediated impairment. Finally, Aβ impaired NMDAR Ca2+ entry at doses much lower than those required for NMDAR internalization, revealing a novel, potent mode of NMDAR regulation by Aβ. SIGNIFICANCE STATEMENT Amyloid β (Aβ) is strongly implicated in Alzheimer's disease. Aβ triggers the elimination of excitatory synapses through a mechanism that requires NMDA receptors (NMDARs). However, little is known about how or whether Aβ influences synaptic NMDAR function. We used an imaging-based assay to investigate the relationship among Aβ binding, activity, and NMDAR function at individual synapses. Aβ triggered a robust impairment of NMDAR Ca2+ entry at most, but not all, synapses. NMDAR function was more severely impaired at highly active synapses and synapses with bound Aβ. Blocking NMDARs during Aβ exposure prevented Aβ-mediated impairment. Together, our experiments reveal a novel use-dependent, potent, and local mode of Aβ-mediated NMDAR impairment.
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80
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Chen J, Hu R, Liao H, Zhang Y, Lei R, Zhang Z, Zhuang Y, Wan Y, Jin P, Feng H, Wan Q. A non-ionotropic activity of NMDA receptors contributes to glycine-induced neuroprotection in cerebral ischemia-reperfusion injury. Sci Rep 2017; 7:3575. [PMID: 28620235 PMCID: PMC5472592 DOI: 10.1038/s41598-017-03909-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/05/2017] [Indexed: 01/01/2023] Open
Abstract
NMDA receptor (NMDAR) is known for its ionotropic function. But recent evidence suggests that NMDAR also has a non-ionotropic property. To determine the role of non-ionotropic activity of NMDARs in clinical relevant conditions, we tested the effect of glycine, a co-agonist of NMDARs, in rat middle cerebral artery occlusion (MCAO), an animal model of cerebral ischemia-reperfusion injury after the animals were injected with the NMDAR channel blocker MK-801 and the glycine receptor antagonist strychnine. We show that glycine reduces the infarct volume in the brain of ischemic stroke animals pre-injected with MK-801 and strychnine. The effect of glycine is sensitive to the antagonist of glycine-GluN1 binding site and blocked by Akt inhibition. In the neurobehavioral tests, glycine improves the functional recovery of stroke animals pre-injected with MK-801 and strychnine. This study suggests that glycine-induced neuroprotection is mediated in part by the non-ionotropic activity of NMDARs via Akt activation in cerebral ischemia-reperfusion injury.
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Affiliation(s)
- Juan Chen
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China. .,Department of Neurology, the Central Hospital of Wuhan, Tongji Medical College of Huazhong University of Science & Technology, 26 Shengli Street, Wuhan, 430014, China.
| | - Rong Hu
- Department of Neurosurgery, Southwest Hospital, Chongqing, 400038, China
| | - Huabao Liao
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Ya Zhang
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Ruixue Lei
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Zhifeng Zhang
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Yang Zhuang
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Yu Wan
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China
| | - Ping Jin
- Department of Neurology, the Central Hospital of Wuhan, Tongji Medical College of Huazhong University of Science & Technology, 26 Shengli Street, Wuhan, 430014, China
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Chongqing, 400038, China
| | - Qi Wan
- Department of Physiology, Collaborative Innovation Center for Brain Science, School of Basic Medical Sciences, School of Medicine, Wuhan University, 185 Donghu Street, Wuhan, Hubei, 430071, China. .,Institute of Neuroregeneration & Neurorehabilitation, Qingdao University School of Medicine, 308 Ningxia Street, Qingdao, 266071, China.
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81
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Grochowska KM, Yuanxiang P, Bär J, Raman R, Brugal G, Sahu G, Schweizer M, Bikbaev A, Schilling S, Demuth HU, Kreutz MR. Posttranslational modification impact on the mechanism by which amyloid-β induces synaptic dysfunction. EMBO Rep 2017; 18:962-981. [PMID: 28420656 DOI: 10.15252/embr.201643519] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 03/13/2017] [Accepted: 03/17/2017] [Indexed: 11/09/2022] Open
Abstract
Oligomeric amyloid-β (Aβ) 1-42 disrupts synaptic function at an early stage of Alzheimer's disease (AD). Multiple posttranslational modifications of Aβ have been identified, among which N-terminally truncated forms are the most abundant. It is not clear, however, whether modified species can induce synaptic dysfunction on their own and how altered biochemical properties can contribute to the synaptotoxic mechanisms. Here, we show that a prominent isoform, pyroglutamated Aβ3(pE)-42, induces synaptic dysfunction to a similar extent like Aβ1-42 but by clearly different mechanisms. In contrast to Aβ1-42, Aβ3(pE)-42 does not directly associate with synaptic membranes or the prion protein but is instead taken up by astrocytes and potently induces glial release of the proinflammatory cytokine TNFα. Moreover, Aβ3(pE)-42-induced synaptic dysfunction is not related to NMDAR signalling and Aβ3(pE)-42-induced impairment of synaptic plasticity cannot be rescued by D1-agonists. Collectively, the data point to a scenario where neuroinflammatory processes together with direct synaptotoxic effects are caused by posttranslational modification of soluble oligomeric Aβ and contribute synergistically to the onset of synaptic dysfunction in AD.
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Affiliation(s)
| | - PingAn Yuanxiang
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Julia Bär
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Emmy-Noether Group "Neuronal Protein Transport", Center for Molecular Neurobiology ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rajeev Raman
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Gemma Brugal
- Department of Biochemistry and Molecular Biology, Faculty of Biology, Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Giriraj Sahu
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michaela Schweizer
- Morphology Unit, Center for Molecular Neurobiology ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Arthur Bikbaev
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Stephan Schilling
- Department of Drug Design and Target Validation MWT, Fraunhofer Institute of Cell Therapy and Immunology IZI Leipzig, Halle, Germany
| | - Hans-Ulrich Demuth
- Department of Drug Design and Target Validation MWT, Fraunhofer Institute of Cell Therapy and Immunology IZI Leipzig, Halle, Germany
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany .,Leibniz Group "Dendritic Organelles and Synaptic Function", Center for Molecular Neurobiology ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Center for Neurodegenerative Diseases, Magdeburg, Germany
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82
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Emerging Synaptic Molecules as Candidates in the Etiology of Neurological Disorders. Neural Plast 2017; 2017:8081758. [PMID: 28331639 PMCID: PMC5346360 DOI: 10.1155/2017/8081758] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/06/2017] [Indexed: 01/06/2023] Open
Abstract
Synapses are complex structures that allow communication between neurons in the central nervous system. Studies conducted in vertebrate and invertebrate models have contributed to the knowledge of the function of synaptic proteins. The functional synapse requires numerous protein complexes with specialized functions that are regulated in space and time to allow synaptic plasticity. However, their interplay during neuronal development, learning, and memory is poorly understood. Accumulating evidence links synapse proteins to neurodevelopmental, neuropsychiatric, and neurodegenerative diseases. In this review, we describe the way in which several proteins that participate in cell adhesion, scaffolding, exocytosis, and neurotransmitter reception from presynaptic and postsynaptic compartments, mainly from excitatory synapses, have been associated with several synaptopathies, and we relate their functions to the disease phenotype.
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83
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Yuzaki M, Aricescu AR. A GluD Coming-Of-Age Story. Trends Neurosci 2017; 40:138-150. [PMID: 28110935 DOI: 10.1016/j.tins.2016.12.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 01/02/2023]
Abstract
The GluD1 and GluD2 receptors form the GluD ionotropic glutamate receptor (iGluR) subfamily. Without known endogenous ligands, they have long been referred to as 'orphan' and remained enigmatic functionally. Recent progress has, however, radically changed this view. Both GluD receptors are expressed in wider brain regions than originally thought. Human genetic studies and analyses of knockout mice have revealed their involvement in multiple neurodevelopmental and psychiatric disorders. The discovery of endogenous ligands, together with structural investigations, has opened the way towards a mechanistic understanding of GluD signaling at central nervous system synapses. These studies have also prompted the hypothesis that all iGluRs, and potentially other neurotransmitter receptors, rely on the cooperative binding of extracellular small-molecule and protein ligands for physiological signaling.
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Affiliation(s)
- Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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84
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Jan A, Jansonius B, Delaidelli A, Somasekharan SP, Bhanshali F, Vandal M, Negri GL, Moerman D, MacKenzie I, Calon F, Hayden MR, Taubert S, Sorensen PH. eEF2K inhibition blocks Aβ42 neurotoxicity by promoting an NRF2 antioxidant response. Acta Neuropathol 2017; 133:101-119. [PMID: 27752775 DOI: 10.1007/s00401-016-1634-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/11/2016] [Accepted: 10/11/2016] [Indexed: 01/01/2023]
Abstract
Soluble oligomers of amyloid-β (Aβ) impair synaptic plasticity, perturb neuronal energy homeostasis, and are implicated in Alzheimer's disease (AD) pathogenesis. Therefore, significant efforts in AD drug discovery research aim to prevent the formation of Aβ oligomers or block their neurotoxicity. The eukaryotic elongation factor-2 kinase (eEF2K) plays a critical role in synaptic plasticity, and couples neurotransmission to local dendritic mRNA translation. Recent evidence indicates that Aβ oligomers activate neuronal eEF2K, suggesting a potential link to Aβ induced synaptic dysfunction. However, a detailed understanding of the role of eEF2K in AD pathogenesis, and therapeutic potential of eEF2K inhibition in AD, remain to be determined. Here, we show that eEF2K activity is increased in postmortem AD patient cortex and hippocampus, and in the hippocampus of aged transgenic AD mice. Furthermore, eEF2K inhibition using pharmacological or genetic approaches prevented the toxic effects of Aβ42 oligomers on neuronal viability and dendrite formation in vitro. We also report that eEF2K inhibition promotes the nuclear factor erythroid 2-related factor (NRF2) antioxidant response in neuronal cells, which was crucial for the beneficial effects of eEF2K inhibition in neurons exposed to Aβ42 oligomers. Accordingly, NRF2 knockdown or overexpression of the NRF2 inhibitor, Kelch-Like ECH-Associated Protein-1 (Keap1), significantly attenuated the neuroprotection associated with eEF2K inhibition. Finally, genetic deletion of the eEF2K ortholog efk-1 reduced oxidative stress, and improved chemotaxis and serotonin sensitivity in C. elegans expressing human Aβ42 in neurons. Taken together, these findings highlight the potential utility of eEF2K inhibition to reduce Aβ-mediated oxidative stress in AD.
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Affiliation(s)
- Asad Jan
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada
| | - Brandon Jansonius
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada
| | - Alberto Delaidelli
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada
| | | | - Forum Bhanshali
- Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada
| | - Milène Vandal
- Faculté de Pharmacie, Université Laval, Pavillon Ferdinand-Vandry 1050, Avenue de la Médecine, Quebec, QC, G1V 0A6, Canada
| | - Gian Luca Negri
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada
| | - Don Moerman
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Ian MacKenzie
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval, Pavillon Ferdinand-Vandry 1050, Avenue de la Médecine, Quebec, QC, G1V 0A6, Canada
| | - Michael R Hayden
- Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada
| | - Stefan Taubert
- Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada
| | - Poul H Sorensen
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada.
- British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3, Canada.
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85
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Latif-Hernandez A, Faldini E, Ahmed T, Balschun D. Separate Ionotropic and Metabotropic Glutamate Receptor Functions in Depotentiation vs. LTP: A Distinct Role for Group1 mGluR Subtypes and NMDARs. Front Cell Neurosci 2016; 10:252. [PMID: 27872582 PMCID: PMC5098392 DOI: 10.3389/fncel.2016.00252] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 10/14/2016] [Indexed: 01/01/2023] Open
Abstract
Depotentiation (DP) is a mechanism by which synapses that have recently undergone long-term potentiation (LTP) can reverse their synaptic strengthening within a short time-window after LTP induction. Group 1 metabotropic glutamate receptors (mGluRs) were shown to be involved in different forms of LTP and long-term depression (LTD), but little is known about their roles in DP. Here, we generated DP by applying low-frequency stimulation (LFS) at 5 Hz after LTP had been induced by a single train of theta-burst-stimulation (TBS). While application of LFS for 2 min (DP2′) generated only a short-lasting DP that was independent of the activation of N-methyl-D-aspartate receptors (NMDARs) and group 1 mGluRs, LFS given for 8 min (DP8′) induced a robust DP that was maintained for at least 2 h. This strong form of DP was contingent on NMDAR activation. Interestingly, DP8′ appears to include a metabotropic NMDAR function because it was blocked by the competitive NMDAR antagonist D-AP5 but not by the use-dependent inhibitor MK-801 or high Mg2+. Furthermore, DP8′ was enhanced by application of the mGluR1 antagonist (YM 298198, 1 μM). The mGluR5 antagonist 2-Methyl-6(phenylethynyl) pyridine (MPEP, 40 μM), in contrast, failed to affect it. The induction of LTP, in turn, was NMDAR dependent (as tested with D-AP5), and blocked by MPEP but not by YM 298198. These results indicate a functional dissociation of mGluR1 and mGluR5 in two related and consecutively induced types of NMDAR-dependent synaptic plasticity (LTP → DP) with far-reaching consequences for their role in plasticity and learning under normal and pathological conditions.
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Affiliation(s)
| | - Enrico Faldini
- Laboratory of Biological Psychology, KU Leuven Leuven, Belgium
| | - Tariq Ahmed
- Laboratory of Biological Psychology, KU Leuven Leuven, Belgium
| | - Detlef Balschun
- Laboratory of Biological Psychology, KU Leuven Leuven, Belgium
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86
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Li LJ, Hu R, Lujan B, Chen J, Zhang JJ, Nakano Y, Cui TY, Liao MX, Chen JC, Man HY, Feng H, Wan Q. Glycine Potentiates AMPA Receptor Function through Metabotropic Activation of GluN2A-Containing NMDA Receptors. Front Mol Neurosci 2016; 9:102. [PMID: 27807405 PMCID: PMC5069295 DOI: 10.3389/fnmol.2016.00102] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/29/2016] [Indexed: 11/13/2022] Open
Abstract
NMDA receptors are Ca2+-permeable ion channels. The activation of NMDA receptors requires agonist glutamate and co-agonist glycine. Recent evidence indicates that NMDA receptor also has metabotropic function. Here we report that in cultured mouse hippocampal neurons, glycine increases AMPA receptor-mediated currents independent of the channel activity of NMDA receptors and the activation of glycine receptors. The potentiation of AMPA receptor function by glycine is antagonized by the inhibition of ERK1/2. In the hippocampal neurons and in the HEK293 cells transfected with different combinations of NMDA receptors, glycine preferentially acts on GluN2A-containing NMDA receptors (GluN2ARs), but not GluN2B-containing NMDA receptors (GluN2BRs), to enhance ERK1/2 phosphorylation independent of the channel activity of GluN2ARs. Without requiring the channel activity of GluN2ARs, glycine increases AMPA receptor-mediated currents through GluN2ARs. Thus, these results reveal a metabotropic function of GluN2ARs in mediating glycine-induced potentiation of AMPA receptor function via ERK1/2 activation.
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Affiliation(s)
- Li-Jun Li
- Department of Physiology, Toronto Western Research Institute, School of Medicine, University of Toronto Toronto, Canada
| | - Rong Hu
- Department of Physiology and Cell Biology, University of Nevada School of MedicineReno, NV, USA; Department of Neurosurgery, Southwest HospitalChongqing, China
| | - Brendan Lujan
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Juan Chen
- Department of Neurology, Central Hospital of Wuhan Wuhan, China
| | - Jian-Jian Zhang
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University School of Medicine Wuhan, China
| | - Yasuko Nakano
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Tian-Yuan Cui
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Ming-Xia Liao
- Department of Physiology and Cell Biology, University of Nevada School of Medicine Reno, NV, USA
| | - Jin-Cao Chen
- Department of Neurosurgery, Zhongnan Hospital, Wuhan University School of Medicine Wuhan, China
| | - Heng-Ye Man
- Department of Biology, Boston University Boston, MA, USA
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital Chongqing, China
| | - Qi Wan
- Department of Physiology, Toronto Western Research Institute, School of Medicine, University of TorontoToronto, Canada; Department of Physiology and Cell Biology, University of Nevada School of MedicineReno, NV, USA; Department of Neurosurgery, Zhongnan Hospital, Wuhan University School of MedicineWuhan, China; Department of Physiology, School of Basic Medical Sciences, Wuhan University School of MedicineWuhan, China
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87
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Amyloid-β effects on synapses and memory require AMPA receptor subunit GluA3. Proc Natl Acad Sci U S A 2016; 113:E6526-E6534. [PMID: 27708157 DOI: 10.1073/pnas.1614249113] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyloid-β (Aβ) is a prime suspect for causing cognitive deficits during the early phases of Alzheimer's disease (AD). Experiments in AD mouse models have shown that soluble oligomeric clusters of Aβ degrade synapses and impair memory formation. We show that all Aβ-driven effects measured in these mice depend on AMPA receptor (AMPAR) subunit GluA3. Hippocampal neurons that lack GluA3 were resistant against Aβ-mediated synaptic depression and spine loss. In addition, Aβ oligomers blocked long-term synaptic potentiation only in neurons that expressed GluA3. Furthermore, although Aβ-overproducing mice showed significant memory impairment, memories in GluA3-deficient congenics remained unaffected. These experiments indicate that the presence of GluA3-containing AMPARs is critical for Aβ-mediated synaptic and cognitive deficits.
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88
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Glycine triggers a non-ionotropic activity of GluN2A-containing NMDA receptors to confer neuroprotection. Sci Rep 2016; 6:34459. [PMID: 27694970 PMCID: PMC5046082 DOI: 10.1038/srep34459] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/14/2016] [Indexed: 11/08/2022] Open
Abstract
Ionotropic activation of NMDA receptors (NMDARs) requires agonist glutamate and co-agonist glycine. Here we show that glycine enhances the activation of cell survival-promoting kinase Akt in cultured cortical neurons in which both the channel activity of NMDARs and the glycine receptors are pre-inhibited. The effect of glycine is reduced by shRNA-mediated knockdown of GluN2A subunit-containing NMDARs (GluN2ARs), suggesting that a non-ionotropic activity of GluN2ARs mediates glycine-induced Akt activation. In support of this finding, glycine enhances Akt activation in HEK293 cells over-expressing GluN2ARs. The effect of glycine on Akt activation is sensitive to the antagonist of glycine-GluN1 binding site. As a functional consequence, glycine protects against excitotoxicity-induced neuronal death through the non-ionotropic activity of GluN2ARs and the neuroprotective effect is attenuated by Akt inhibition. Thus, this study reveals an unexpected role of glycine in eliciting a non-ionotropic activity of GluN2ARs to confer neuroprotection via Akt activation.
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89
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GluN3A promotes NMDA spiking by enhancing synaptic transmission in Huntington's disease models. Neurobiol Dis 2016; 93:47-56. [DOI: 10.1016/j.nbd.2016.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/23/2016] [Accepted: 04/06/2016] [Indexed: 11/18/2022] Open
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90
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Physiological Roles of Non-Neuronal NMDA Receptors. Trends Pharmacol Sci 2016; 37:750-767. [DOI: 10.1016/j.tips.2016.05.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 12/14/2022]
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91
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Dore K, Aow J, Malinow R. The Emergence of NMDA Receptor Metabotropic Function: Insights from Imaging. Front Synaptic Neurosci 2016; 8:20. [PMID: 27516738 PMCID: PMC4963461 DOI: 10.3389/fnsyn.2016.00020] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/06/2016] [Indexed: 01/19/2023] Open
Abstract
The NMDA receptor (R) participates in many important physiological and pathological processes. For example, its activation is required for both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission, cellular models of learning and memory. Furthermore, it may play a role in the actions of amyloid-beta on synapses as well as in the signaling leading to cell death following stroke. Until recently, these processes were thought to be mediated by ion-flux through the receptor. Using a combination of imaging and electrophysiological approaches, ion-flux independent functions of the NMDAR were recently examined. In this review, we will discuss the role of metabotropic NMDAR function in LTD and synaptic dysfunction.
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Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
| | - Jonathan Aow
- Genome Institute of Singapore Singapore, Singapore
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
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92
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Gilson V, Mbebi-Liegeois C, Sellal F, de Barry J. Effects of Low Amyloid-β (Aβ) Concentration on Aβ1-42 Oligomers Binding and GluN2B Membrane Expression. J Alzheimers Dis 2016; 47:453-66. [PMID: 26401567 PMCID: PMC4923730 DOI: 10.3233/jad-142529] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Numerous studies have shown that amyloid-β (Aβ) modulate intracellular metabolic cascades and an intracellular Ca2+ homeostasis and a cell surface NMDA receptor expression alteration in Alzheimer’s disease (AD). However most of these findings have been obtained by using non-physiological Aβ concentrations. The present study deals with the effect of low Aβ concentrations on cellular homeostasis. We used nerve growth factor-differentiated PC12 cells and murine cortical neurons sequentially treated with low chronic monomeric or small oligomeric Aβ concentrations and high acute oligomeric Aβ concentrations to bring out a priming effect of chronic treatment on subsequently high Aβ concentrations-elicited cellular response. Both cell types indeed displayed an enhanced capacity to bind oligomeric Aβ after monomeric or small oligomeric Aβ application. Furthermore, the results show that monomeric Aβ1–42 application to the cells induces an increase of the Ca2+-response and of the membrane expression of the extrasynaptic subunit of the NMDA receptor GluN2B in PC12 cells, while the opposite effects were observed in cultured neurons. This suggests a sequential interaction of Aβ with the cellular plasma membrane involving monomers or small Aβ oligomers which would facilitate the binding of the deleterious high molecular Aβ oligomers. This mechanism would explain the slow progression of AD in the human nervous system and the deep gradient of neuronal death observed around the amyloid plaques in the nervous tissue.
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Affiliation(s)
- Virginie Gilson
- Institut des Neurosciences Cellulaires et Intégratives-CNRS, Strasbourg, France.,Universitéde Strasbourg, Strasbourg, France
| | - Corinne Mbebi-Liegeois
- Institut des Neurosciences Cellulaires et Intégratives-CNRS, Strasbourg, France.,Innovative Health Diagnostics SAS, Strasbourg, France
| | - François Sellal
- Universitéde Strasbourg, Strasbourg, France.,CMRR Alsace, Centre Hospitalier de Colmar, France
| | - Jean de Barry
- Institut des Neurosciences Cellulaires et Intégratives-CNRS, Strasbourg, France.,Universitéde Strasbourg, Strasbourg, France
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93
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Yan R, Fan Q, Zhou J, Vassar R. Inhibiting BACE1 to reverse synaptic dysfunctions in Alzheimer's disease. Neurosci Biobehav Rev 2016; 65:326-40. [PMID: 27044452 PMCID: PMC4856578 DOI: 10.1016/j.neubiorev.2016.03.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/25/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022]
Abstract
Over the past two decades, many studies have identified significant contributions of toxic β-amyloid peptides (Aβ) to the etiology of Alzheimer's disease (AD), which is the most common age-dependent neurodegenerative disease. AD is also recognized as a disease of synaptic failure. Aβ, generated by sequential proteolytic cleavages of amyloid precursor protein (APP) by BACE1 and γ-secretase, is one of major culprits that cause this failure. In this review, we summarize current findings on how BACE1-cleaved APP products impact learning and memory through proteins localized on glutamatergic, GABAergic, and dopaminergic synapses. Considering the broad effects of Aβ on all three types of synapses, BACE1 inhibition emerges as a practical approach for ameliorating Aβ-mediated synaptic dysfunctions. Since BACE1 inhibitory drugs are currently in clinical trials, this review also discusses potential complications arising from BACE1 inhibition. We emphasize that the benefits of BACE1 inhibitory drugs will outweigh the concerns.
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Affiliation(s)
- Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - John Zhou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Robert Vassar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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94
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Abstract
Provocative emerging evidence suggests that the N-methyl-d-aspartate (NMDA) receptor can signal in the absence of ion flux through the receptor. This non-ionotropic signaling is thought to be due to agonist-induced conformational changes in the receptor, independently of channel opening. Non-ionotropic NMDA receptor signaling has been proposed to be sufficient to induce synaptic long-term depression (LTD), directly challenging the decades-old model that prolonged low-level calcium influx is required to induce LTD. Here, we briefly review these recent findings, focusing primarily on the potential role of non-ionotropic signaling in NMDA receptor-mediated LTD. Further reports concerning additional roles of non-ionotropic NMDA receptor signaling are also discussed. If validated, this new view of NMDA receptor-mediated signaling will usher in an exciting new era of exploring synapse function and dysfunction.
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Affiliation(s)
- John A Gray
- Center for Neuroscience, University of California, Davis, CA, USA; Department of Neurology, University of California, Davis, CA, USA
| | - Karen Zito
- Center for Neuroscience, University of California, Davis, CA, USA; Department of Neurobiology, Physiology & Behavior, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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95
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Foster TC, Kyritsopoulos C, Kumar A. Central role for NMDA receptors in redox mediated impairment of synaptic function during aging and Alzheimer's disease. Behav Brain Res 2016; 322:223-232. [PMID: 27180169 DOI: 10.1016/j.bbr.2016.05.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/15/2016] [Accepted: 05/05/2016] [Indexed: 01/07/2023]
Abstract
Increased human longevity has magnified the negative impact that aging can have on cognitive integrity of older individuals experiencing some decline in cognitive function. Approximately 30% of the elderly will have cognitive problems that influence their independence. Impaired executive function and memory performance are observed in normal aging and yet can be an early sign of a progressive cognitive impairment of Alzheimer's disease (AD), the most common form of dementia. Brain regions that are vulnerable to aging exhibit the earliest pathology of AD. Senescent synaptic function is observed as a shift in Ca2+-dependent synaptic plasticity and similar mechanisms are thought to contribute to the early cognitive deficits associated with AD. In the case of aging, intracellular redox state mediates a shift in Ca2+ regulation including N-methyl-d-aspartate (NMDA) receptor hypofunction and increased Ca2+ release from intracellular stores to alter synaptic plasticity. AD can interact with these aging processes such that molecules linked to AD, β-amyloid (Aβ) and mutated presenilin 1 (PS1), can also degrade NMDA receptor function, promote Ca2+ release from intracellular stores, and may increase oxidative stress. Thus, age is one of the most important predictors of AD and brain aging likely contributes to the onset of AD. The focus of this review article is to provide an update on mechanisms that contribute to the senescent synapse and possible interactions with AD-related molecules, with special emphasis on regulation of NMDA receptors.
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Affiliation(s)
- T C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America.
| | - C Kyritsopoulos
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America
| | - A Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, United States of America.
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96
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Alfonso SI, Callender JA, Hooli B, Antal CE, Mullin K, Sherman MA, Lesné SE, Leitges M, Newton AC, Tanzi RE, Malinow R. Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer's disease. Sci Signal 2016; 9:ra47. [PMID: 27165780 PMCID: PMC5154619 DOI: 10.1126/scisignal.aaf6209] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is a progressive dementia disorder characterized by synaptic degeneration and amyloid-β (Aβ) accumulation in the brain. Through whole-genome sequencing of 1345 individuals from 410 families with late-onset AD (LOAD), we identified three highly penetrant variants in PRKCA, the gene that encodes protein kinase Cα (PKCα), in five of the families. All three variants linked with LOAD displayed increased catalytic activity relative to wild-type PKCα as assessed in live-cell imaging experiments using a genetically encoded PKC activity reporter. Deleting PRKCA in mice or adding PKC antagonists to mouse hippocampal slices infected with a virus expressing the Aβ precursor CT100 revealed that PKCα was required for the reduced synaptic activity caused by Aβ. In PRKCA(-/-) neurons expressing CT100, introduction of PKCα, but not PKCα lacking a PDZ interaction moiety, rescued synaptic depression, suggesting that a scaffolding interaction bringing PKCα to the synapse is required for its mediation of the effects of Aβ. Thus, enhanced PKCα activity may contribute to AD, possibly by mediating the actions of Aβ on synapses. In contrast, reduced PKCα activity is implicated in cancer. Hence, these findings reinforce the importance of maintaining a careful balance in the activity of this enzyme.
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Affiliation(s)
- Stephanie I Alfonso
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julia A Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Basavaraj Hooli
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Corina E Antal
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kristina Mullin
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Mathew A Sherman
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Sylvain E Lesné
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Michael Leitges
- Biotechnology Centre of Oslo, University of Oslo, Oslo 0317, Norway
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| | - Roberto Malinow
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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97
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Guntupalli S, Widagdo J, Anggono V. Amyloid-β-Induced Dysregulation of AMPA Receptor Trafficking. Neural Plast 2016; 2016:3204519. [PMID: 27073700 PMCID: PMC4814684 DOI: 10.1155/2016/3204519] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/28/2016] [Indexed: 01/22/2023] Open
Abstract
Evidence from neuropathological, genetic, animal model, and biochemical studies has indicated that the accumulation of amyloid-beta (Aβ) is associated with, and probably induces, profound neuronal changes in brain regions critical for memory and cognition in the development of Alzheimer's disease (AD). There is considerable evidence that synapses are particularly vulnerable to AD, establishing synaptic dysfunction as one of the earliest events in pathogenesis, prior to neuronal loss. It is clear that excessive Aβ levels can disrupt excitatory synaptic transmission and plasticity, mainly due to dysregulation of the AMPA and NMDA glutamate receptors in the brain. Importantly, AMPA receptors are the principal glutamate receptors that mediate fast excitatory neurotransmission. This is essential for synaptic plasticity, a cellular correlate of learning and memory, which are the cognitive functions that are most disrupted in AD. Here we review recent advances in the field and provide insights into the molecular mechanisms that underlie Aβ-induced dysfunction of AMPA receptor trafficking. This review focuses primarily on NMDA receptor- and metabotropic glutamate receptor-mediated signaling. In particular, we highlight several mechanisms that underlie synaptic long-term depression as common signaling pathways that are hijacked by the neurotoxic effects of Aβ.
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Affiliation(s)
- Sumasri Guntupalli
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jocelyn Widagdo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Victor Anggono
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
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98
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Kaleka KS, Gerges NZ. Neurogranin restores amyloid β-mediated synaptic transmission and long-term potentiation deficits. Exp Neurol 2015; 277:115-123. [PMID: 26721336 DOI: 10.1016/j.expneurol.2015.12.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 12/08/2015] [Accepted: 12/18/2015] [Indexed: 11/16/2022]
Abstract
Amyloid β (Aβ) is widely considered one of the early causes of cognitive deficits observed in Alzheimer's disease. Many of the deficits caused by Aβ are attributed to its disruption of synaptic function represented by its blockade of long-term potentiation (LTP) and its induction of synaptic depression. Identifying pathways that reverse these synaptic deficits may open the door to new therapeutic targets. In this study, we explored the possibility that Neurogranin (Ng)-a postsynaptic calmodulin (CaM) targeting protein that enhances synaptic function-may rescue Aβ-mediated deficits in synaptic function. Our results show that Ng is able to reverse synaptic depression and LTP deficits induced by Aβ. Furthermore, Ng's restoration of synaptic transmission is through the insertion of GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors (AMPARs). These restorative effects of Ng are dependent on the interaction of Ng and CaM and CaM-dependent activation of CaMKII. Overall, this study identifies a novel mechanism to rescue synaptic deficits induced by Aβ oligomers. It also suggests Ng and CaM signaling as potential therapeutic targets for Alzheimer's disease as well as important tools to further explore the pathophysiology underlying the disease.
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Affiliation(s)
- Kanwardeep Singh Kaleka
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 West Watertown Plank Rd., Milwaukee, WI 53132, United States; Neuroscience Research Center, Medical College of Wisconsin, 8701 West Watertown Plank Rd., Milwaukee, WI 53132, United States
| | - Nashaat Z Gerges
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 West Watertown Plank Rd., Milwaukee, WI 53132, United States; Neuroscience Research Center, Medical College of Wisconsin, 8701 West Watertown Plank Rd., Milwaukee, WI 53132, United States.
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99
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Abstract
UNLABELLED The elimination of dendritic spine synapses is a critical step in the refinement of neuronal circuits during development of the cerebral cortex. Several studies have shown that activity-induced shrinkage and retraction of dendritic spines depend on activation of the NMDA-type glutamate receptor (NMDAR), which leads to influx of extracellular calcium ions and activation of calcium-dependent phosphatases that modify regulators of the spine cytoskeleton, suggesting that influx of extracellular calcium ions drives spine shrinkage. Intriguingly, a recent report revealed a novel non-ionotropic function of the NMDAR in the regulation of synaptic strength, which relies on glutamate binding but is independent of ion flux through the receptor (Nabavi et al., 2013). Here, we tested whether non-ionotropic NMDAR signaling could also play a role in driving structural plasticity of dendritic spines. Using two-photon glutamate uncaging and time-lapse imaging of rat hippocampal CA1 neurons, we show that low-frequency glutamatergic stimulation results in shrinkage of dendritic spines even in the presence of the NMDAR d-serine/glycine binding site antagonist 7-chlorokynurenic acid (7CK), which fully blocks NMDAR-mediated currents and Ca(2+) transients. Notably, application of 7CK or MK-801 also converts spine enlargement resulting from a high-frequency uncaging stimulus into spine shrinkage, demonstrating that strong Ca(2+) influx through the NMDAR normally overcomes a non-ionotropic shrinkage signal to drive spine growth. Our results support a model in which NMDAR signaling, independent of ion flux, drives structural shrinkage at spiny synapses. SIGNIFICANCE STATEMENT Dendritic spine elimination is vital for the refinement of neural circuits during development and has been linked to improvements in behavioral performance in the adult. Spine shrinkage and elimination have been widely accepted to depend on Ca(2+) influx through NMDA-type glutamate receptors (NMDARs) in conjunction with long-term depression (LTD) of synaptic strength. Here, we use two-photon glutamate uncaging and time-lapse imaging to show that non-ionotropic NMDAR signaling can drive shrinkage of dendritic spines, independent of NMDAR-mediated Ca(2+) influx. Signaling through p38 MAPK was required for this activity-dependent spine shrinkage. Our results provide fundamental new insights into the signaling mechanisms that support experience-dependent changes in brain structure.
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100
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Miyamoto T, Kim D, Knox JA, Johnson E, Mucke L. Increasing the Receptor Tyrosine Kinase EphB2 Prevents Amyloid-β-induced Depletion of Cell Surface Glutamate Receptors by a Mechanism That Requires the PDZ-binding Motif of EphB2 and Neuronal Activity. J Biol Chem 2015; 291:1719-1734. [PMID: 26589795 PMCID: PMC4722453 DOI: 10.1074/jbc.m115.666529] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 11/11/2022] Open
Abstract
Diverse lines of evidence suggest that amyloid-β (Aβ) peptides causally contribute to the pathogenesis of Alzheimer disease (AD), the most frequent neurodegenerative disorder. However, the mechanisms by which Aβ impairs neuronal functions remain to be fully elucidated. Previous studies showed that soluble Aβ oligomers interfere with synaptic functions by depleting NMDA-type glutamate receptors (NMDARs) from the neuronal surface and that overexpression of the receptor tyrosine kinase EphB2 can counteract this process. Through pharmacological treatments and biochemical analyses of primary neuronal cultures expressing wild-type or mutant forms of EphB2, we demonstrate that this protective effect of EphB2 depends on its PDZ-binding motif and the presence of neuronal activity but not on its kinase activity. We further present evidence that the protective effect of EphB2 may be mediated by the AMPA-type glutamate receptor subunit GluA2, which can become associated with the PDZ-binding motif of EphB2 through PDZ domain-containing proteins and can promote the retention of NMDARs in the membrane. In addition, we show that the Aβ-induced depletion of surface NMDARs does not depend on several factors that have been implicated in the pathogenesis of Aβ-induced neuronal dysfunction, including aberrant neuronal activity, tau, prion protein (PrPC), and EphB2 itself. Thus, although EphB2 does not appear to be directly involved in the Aβ-induced depletion of NMDARs, increasing its expression may counteract this pathogenic process through a neuronal activity- and PDZ-dependent regulation of AMPA-type glutamate receptors.
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Affiliation(s)
- Takashi Miyamoto
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158
| | - Daniel Kim
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and
| | - Joseph A Knox
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and
| | - Erik Johnson
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158
| | - Lennart Mucke
- From the Gladstone Institute of Neurological Disease, San Francisco, California 94158 and; Department of Neurology, University of California, San Francisco, California 94158.
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