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Manning A, Bender PTR, Boyd-Pratt H, Mendelson BZ, Hruska M, Anderson CT. Trans-synaptic Association of Vesicular Zinc Transporter 3 and Shank3 Supports Synapse-Specific Dendritic Spine Structure and Function in the Mouse Auditory Cortex. J Neurosci 2024; 44:e0619242024. [PMID: 38830758 PMCID: PMC11236586 DOI: 10.1523/jneurosci.0619-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/17/2024] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Shank3 is a synaptic scaffolding protein that assists in tethering and organizing structural proteins and glutamatergic receptors in the postsynaptic density of excitatory synapses. The localization of Shank3 at excitatory synapses and the formation of stable Shank3 complexes is regulated by the binding of zinc to the C-terminal sterile-alpha-motif (SAM) domain of Shank3. Mutations in the SAM domain of Shank3 result in altered synaptic function and morphology, and disruption of zinc in synapses that express Shank3 leads to a reduction of postsynaptic proteins important for synaptic structure and function. This suggests that zinc supports the localization of postsynaptic proteins via Shank3. Many regions of the brain are highly enriched with free zinc inside glutamatergic vesicles at presynaptic terminals. At these synapses, zinc transporter 3 (ZnT3) moves zinc into vesicles where it is co-released with glutamate. Alterations in ZnT3 are implicated in multiple neurodevelopmental disorders, and ZnT3 knock-out (KO) mice-which lack synaptic zinc-show behavioral deficits associated with autism spectrum disorder and schizophrenia. Here we show that male and female ZnT3 KO mice have smaller dendritic spines and miniature excitatory postsynaptic current amplitudes than wildtype (WT) mice in the auditory cortex. Additionally, spine size deficits in ZnT3 KO mice are restricted to synapses that express Shank3. In WT mice, synapses that express both Shank3 and ZnT3 have larger spines compared to synapses that express Shank3 but not ZnT3. Together these findings suggest a mechanism whereby presynaptic ZnT3-dependent zinc supports postsynaptic structure and function via Shank3 in a synapse-specific manner.
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Affiliation(s)
- Abbey Manning
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Philip T R Bender
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Helen Boyd-Pratt
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
- Clinical and Translational Science Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Benjamin Z Mendelson
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Martin Hruska
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Charles T Anderson
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
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2
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Harvey J. Novel Leptin-Based Therapeutic Strategies to Limit Synaptic Dysfunction in Alzheimer's Disease. Int J Mol Sci 2024; 25:7352. [PMID: 39000459 PMCID: PMC11242278 DOI: 10.3390/ijms25137352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/01/2024] [Accepted: 07/02/2024] [Indexed: 07/16/2024] Open
Abstract
Accumulation of hyper-phosphorylated tau and amyloid beta (Aβ) are key pathological hallmarks of Alzheimer's disease (AD). Increasing evidence indicates that in the early pre-clinical stages of AD, phosphorylation and build-up of tau drives impairments in hippocampal excitatory synaptic function, which ultimately leads to cognitive deficits. Consequently, limiting tau-related synaptic abnormalities may have beneficial effects in AD. There is now significant evidence that the hippocampus is an important brain target for the endocrine hormone leptin and that leptin has pro-cognitive properties, as activation of synaptic leptin receptors markedly influences higher cognitive processes including learning and memory. Clinical studies have identified a link between the circulating leptin levels and the risk of AD, such that AD risk is elevated when leptin levels fall outwith the physiological range. This has fuelled interest in targeting the leptin system therapeutically. Accumulating evidence supports this possibility, as numerous studies have shown that leptin has protective effects in a variety of models of AD. Recent findings have demonstrated that leptin has beneficial effects in the preclinical stages of AD, as leptin prevents the early synaptic impairments driven by tau protein and amyloid β. Here we review recent findings that implicate the leptin system as a potential novel therapeutic target in AD.
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Affiliation(s)
- Jenni Harvey
- Department of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK
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3
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Lebedeva M, Kubištová A, Spišská V, Filipovská E, Pačesová D, Svobodová I, Kuchtiak V, Balík A, Bendová Z. The disruption of circadian rhythmicity of gene expression in the hippocampus and associated structures in Gria2 R/R mice; a comparison with C57BL/6J and Adar2 -/- mice strains. Brain Res 2024; 1826:148739. [PMID: 38157956 DOI: 10.1016/j.brainres.2023.148739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/18/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
Adar2-/- mice are a widely used model for studying the physiological consequences of reduced RNA editing. These mice are viable only when the Q/R editing site of the Gria2 subunit of the AMPA receptor is constitutively mutated to the codon for arginine, and Gria2R/R mice often serve as the sole control for Adar2-/- mice. Our study aimed to investigate whether ADAR2 inactivity and the Gria2R/R phenotype affect the rhythmicity of the circadian clock gene pattern and the expression of Gria1 and Gria2 subunits in the suprachiasmatic nucleus (SCN), hippocampus, parietal cortex and liver. Our data show that Gria2R/R mice completely lost circadian rhythmicity in the hippocampus compared to Adar2-/- mice. Compared to C57BL/6J mice, the expression profiles in the hippocampus and parietal cortex of Gria2R/R mice differ to the same extent as in Adar2-/-. No alterations were detected in the circadian profiles in the livers. These data suggest that the natural gradual postnatal increase in the editing of the Q/R site of the Gria2 subunit may be important for the development of circadian clockwork in some brain structures, and the use of Gria2R/R mice as the only control to Adar2-/- mice in the experiments dependent on the hippocampus and parietal cortex should therefore be considered.
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Affiliation(s)
- Maria Lebedeva
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic
| | - Aneta Kubištová
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Veronika Spišská
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Eva Filipovská
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Dominika Pačesová
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Irena Svobodová
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Viktor Kuchtiak
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Balík
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Zdeňka Bendová
- Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic.
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4
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Harvey J. Food for Thought: Leptin and Hippocampal Synaptic Function. Front Pharmacol 2022; 13:882158. [PMID: 35784728 PMCID: PMC9247348 DOI: 10.3389/fphar.2022.882158] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
It is well documented that the endocrine hormone, leptin controls energy homeostasis by providing key signals to specific hypothalamic nuclei. However, our knowledge of leptin’s central actions has advanced considerably over the last 20 years, with the hippocampus now established as an important brain target for this hormone. Leptin receptors are highly localised to hippocampal synapses, and increasing evidence reveals that activation of synaptically located leptin receptors markedly impacts cognitive processes, and specifically hippocampal-dependent learning and memory. Here, we review the recent actions of leptin at hippocampal synapses and explore the consequences for brain health and disease.
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5
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Panopoulou M, Schlüter OM. Ca 2+-permeable AMPA receptors set the threshold for retrieval of drug memories. Mol Psychiatry 2022; 27:2868-2878. [PMID: 35296806 DOI: 10.1038/s41380-022-01505-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 02/13/2022] [Accepted: 02/22/2022] [Indexed: 11/09/2022]
Abstract
Frequent relapse prevents the successful treatment of substance use disorders and is triggered in part by retrieval of drug-associated memories. Drug-conditioned behaviours in rodents are reinstated upon drug memory retrieval following re-exposure to cues previously associated with the drug, or the drug itself. Therapies based on mechanistic insights from rodent studies have focused on amnesic procedures of cue-drug associations but with so far limited success. Conversely, more recent studies propose that inhibiting drug memory retrieval offers improved anti-relapse efficacy. However, mechanisms of memory retrieval are poorly understood. Here, we used a conditioned place preference (CPP) procedure in mice to investigate the cellular and molecular underpinnings of drug-induced memory retrieval. After extinction training of CPP, Ca2+-permeable AMPA receptors (CP-AMPARs) accumulated at drug-generated silent synapses of nucleus accumbens (NAc) medium spiny neurons. The NAc CP-AMPARs regulated the retrieval mechanism of drug memories after extinction. Specifically, we used different priming doses of cocaine, fentanyl, or a cue associated with drug exposure to reinstate CPP, providing different memory retrieval conditions. Although both high and low doses of these two drugs induced CPP reinstatement, compromising CP-AMPAR accumulation impaired CPP reinstatement, induced by low doses of each drug or the cue. This threshold effect was mediated by NAc CP-AMPARs as region specific knock-down of PSD-95 prevented low-dose cocaine-induced retrieval selectively. These results demonstrate the NAc as a brain region and CP-AMPARs as key synaptic substrates that govern the threshold for drug-induced retrieval and behavioural expression of drug memories.
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Affiliation(s)
- Myrto Panopoulou
- Department of Psychiatry and Psychotherapy, University Medical Center, D-37075, Göttingen, Germany.,International Max Planck Research School for Neurosciences, D-37077, Göttingen, Germany
| | - Oliver M Schlüter
- Department of Psychiatry and Psychotherapy, University Medical Center, D-37075, Göttingen, Germany. .,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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6
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Marcondes LA, de C Myskiw J, Nachtigall EG, Narvaes RF, Izquierdo I, Furini CRG. PKMζ maintains remote contextual fear memory by inhibiting GluA2-dependent AMPA receptor endocytosis in the prelimbic cortex. Neuroscience 2021; 497:97-106. [PMID: 34968669 DOI: 10.1016/j.neuroscience.2021.12.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/10/2021] [Accepted: 12/21/2021] [Indexed: 10/19/2022]
Abstract
Fear memories allow animals to recognize and adequately respond to dangerous situations. The prelimbic cortex (PrL) is a crucial node in the circuitry that encodes contextual fear memory, and its activity is central for fear memory expression over time. However, while PrL has been implicated in contextual fear memory storage, the molecular mechanisms underlying its maintenance remain unclear. Protein kinase M zeta (PKMζ) is a persistently active enzyme which has been shown to maintain many forms of memories by inhibiting the endocytosis of GluA2-containing AMPA receptors. Therefore, we hypothesized that PKMζ action upon GluA2-containing AMPARs could be a mechanism for contextual fear memory maintenance in the PrL. To test this hypothesis, we trained rats in a contextual fear conditioning (CFC) paradigm and administered intra-PrL infusions of the PKMζ inhibitor ZIP, the GluA2-dependent endocytosis inhibitor GluA23Y or the inactive peptide GluA23Y(s), either two or twenty days after conditioning, and assessed long-term memory retention twenty-four hours later. We found that acute inhibition of GluA2-dependent AMPAR endocytosis in the PrL does not affect recent or remote contextual fear memory maintenance. Also, PKMζ inhibition in the PrL does not impair the maintenance of recent contextual fear memory. However, we found that inhibition of prelimbic PKMζ at a remote time point disrupted contextual fear memory maintenance, and that blocking GluA2-dependent removal of AMPARs prevents this impairment. Our results confirm the central role of PrL in fear memory and identify PKMζ-induced inhibition of GluA2-containing AMPAR endocytosis as a key mechanism governing remote contextual fear memory maintenance.
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Affiliation(s)
- Lucas A Marcondes
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Jociane de C Myskiw
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Eduarda G Nachtigall
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Rodrigo F Narvaes
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Ivan Izquierdo
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Cristiane R G Furini
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil.
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7
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Cepeda-Prado EA, Khodaie B, Quiceno GD, Beythien S, Edelmann E, Lessmann V. Calcium-Permeable AMPA Receptors Mediate Timing-Dependent LTP Elicited by Low Repeat Coincident Pre- and Postsynaptic Activity at Schaffer Collateral-CA1 Synapses. Cereb Cortex 2021; 32:1682-1703. [PMID: 34498663 DOI: 10.1093/cercor/bhab306] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 12/26/2022] Open
Abstract
High-frequency stimulation induced long-term potentiation (LTP) and low-frequency stimulation induced LTD are considered as cellular models of memory formation. Interestingly, spike timing-dependent plasticity (STDP) can induce equally robust timing-dependent LTP (t-LTP) and t-LTD in response to low frequency repeats of coincident action potential (AP) firing in presynaptic and postsynaptic cells. Commonly, STDP paradigms relying on 25-100 repeats of coincident AP firing are used to elicit t-LTP or t-LTD, but the minimum number of repeats required for successful STDP is barely explored. However, systematic investigation of physiologically relevant low repeat STDP paradigms is of utmost importance to explain learning mechanisms in vivo. Here, we examined low repeat STDP at Schaffer collateral-CA1 synapses by pairing one presynaptic AP with either one postsynaptic AP (1:1 t-LTP), or a burst of 4 APs (1:4 t-LTP) and found 3-6 repeats to be sufficient to elicit t-LTP. 6× 1:1 t-LTP required postsynaptic Ca2+ influx via NMDARs and L-type VGCCs and was mediated by increased presynaptic glutamate release. In contrast, 1:4 t-LTP depended on postsynaptic metabotropic GluRs and ryanodine receptor signaling and was mediated by postsynaptic insertion of AMPA receptors. Unexpectedly, both 6× t-LTP variants were strictly dependent on activation of postsynaptic Ca2+-permeable AMPARs but were differentially regulated by dopamine receptor signaling. Our data show that synaptic changes induced by only 3-6 repeats of mild STDP stimulation occurring in ≤10 s can take place on time scales observed also during single trial learning.
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Affiliation(s)
- Efrain A Cepeda-Prado
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany
| | - Babak Khodaie
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany.,OVGU International ESF-funded Graduate School ABINEP, Magdeburg 39104, Germany
| | - Gloria D Quiceno
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany
| | - Swantje Beythien
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany
| | - Elke Edelmann
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany.,OVGU International ESF-funded Graduate School ABINEP, Magdeburg 39104, Germany.,Center for Behavioral Brain Sciences, Magdeburg 39104, Germany
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität (OVGU), Medizinische Fakultät, Magdeburg 39120, Germany.,OVGU International ESF-funded Graduate School ABINEP, Magdeburg 39104, Germany.,Center for Behavioral Brain Sciences, Magdeburg 39104, Germany
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8
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Park P, Kang H, Georgiou J, Zhuo M, Kaang BK, Collingridge GL. Further evidence that CP-AMPARs are critically involved in synaptic tag and capture at hippocampal CA1 synapses. Mol Brain 2021; 14:26. [PMID: 33526063 PMCID: PMC7851922 DOI: 10.1186/s13041-021-00737-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/16/2021] [Indexed: 11/10/2022] Open
Abstract
The synaptic tag and capture (STC) hypothesis provides an important theoretical basis for understanding the synaptic basis of associative learning. We recently provided pharmacological evidence that calcium-permeable AMPA receptors (CP-AMPARs) are a crucial component of this form of heterosynaptic metaplasticity. Here we have investigated two predictions that arise on the basis of CP-AMPARs serving as a trigger of STC. Firstly, we compared the effects of the order in which we delivered a strong theta burst stimulation (TBS) protocol (75 pulses) and a weak TBS protocol (15 pulses) to two independent inputs. We only observed significant heterosynaptic metaplasticity when the strong TBS preceded the weak TBS. Second, we found that pausing stimulation following either the sTBS or the wTBS for ~20 min largely eliminates the heterosynaptic metaplasticity. These observations are consistent with a process that is triggered by the synaptic insertion of CP-AMPARs and provide a framework for establishing the underlying molecular mechanisms.
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Affiliation(s)
- Pojeong Park
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Heather Kang
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Min Zhuo
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Bong-Kiun Kaang
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
| | - Graham L Collingridge
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK.
- TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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Park P, Georgiou J, Sanderson TM, Ko KH, Kang H, Kim JI, Bradley CA, Bortolotto ZA, Zhuo M, Kaang BK, Collingridge GL. PKA drives an increase in AMPA receptor unitary conductance during LTP in the hippocampus. Nat Commun 2021; 12:413. [PMID: 33462202 PMCID: PMC7814032 DOI: 10.1038/s41467-020-20523-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/08/2020] [Indexed: 01/12/2023] Open
Abstract
Long-term potentiation (LTP) at hippocampal CA1 synapses can be expressed by an increase either in the number (N) of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors or in their single channel conductance (γ). Here, we have established how these distinct synaptic processes contribute to the expression of LTP in hippocampal slices obtained from young adult rodents. LTP induced by compressed theta burst stimulation (TBS), with a 10 s inter-episode interval, involves purely an increase in N (LTPN). In contrast, either a spaced TBS, with a 10 min inter-episode interval, or a single TBS, delivered when PKA is activated, results in LTP that is associated with a transient increase in γ (LTPγ), caused by the insertion of calcium-permeable (CP)-AMPA receptors. Activation of CaMKII is necessary and sufficient for LTPN whilst PKA is additionally required for LTPγ. Thus, two mechanistically distinct forms of LTP co-exist at these synapses.
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Affiliation(s)
- Pojeong Park
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.,Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Thomas M Sanderson
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Kwang-Hee Ko
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
| | - Heather Kang
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada.,Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Ji-Il Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
| | - Clarrisa A Bradley
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.,Neurosciences and Mental Health, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Zuner A Bortolotto
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Min Zhuo
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea.,Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea
| | - Graham L Collingridge
- Glutamate Receptor Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom. .,Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 08826, Korea. .,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada. .,Department of Physiology, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,TANZ Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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10
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Hamilton K, Harvey J. The Neuronal Actions of Leptin and the Implications for Treating Alzheimer's Disease. Pharmaceuticals (Basel) 2021; 14:ph14010052. [PMID: 33440796 PMCID: PMC7827292 DOI: 10.3390/ph14010052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 12/13/2022] Open
Abstract
It is widely accepted that the endocrine hormone leptin controls food intake and energy homeostasis via activation of leptin receptors expressed on hypothalamic arcuate neurons. The hippocampal formation also displays raised levels of leptin receptor expression and accumulating evidence indicates that leptin has a significant impact on hippocampal synaptic function. Thus, cellular and behavioural studies support a cognitive enhancing role for leptin as excitatory synaptic transmission, synaptic plasticity and glutamate receptor trafficking at hippocampal Schaffer collateral (SC)-CA1 synapses are regulated by leptin, and treatment with leptin enhances performance in hippocampus-dependent memory tasks. Recent studies indicate that hippocampal temporoammonic (TA)-CA1 synapses are also a key target for leptin. The ability of leptin to regulate TA-CA1 synapses has important functional consequences as TA-CA1 synapses are implicated in spatial and episodic memory processes. Moreover, degeneration is initiated in the TA pathway at very early stages of Alzheimer's disease, and recent clinical evidence has revealed links between plasma leptin levels and the incidence of Alzheimer's disease (AD). Additionally, accumulating evidence indicates that leptin has neuroprotective actions in various AD models, whereas dysfunctions in the leptin system accelerate AD pathogenesis. Here, we review the data implicating the leptin system as a potential novel target for AD, and the evidence that boosting the hippocampal actions of leptin may be beneficial.
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11
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Wright WJ, Dong Y. Psychostimulant-Induced Adaptations in Nucleus Accumbens Glutamatergic Transmission. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a039255. [PMID: 31964644 DOI: 10.1101/cshperspect.a039255] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Carrying different aspects of emotional and motivational signals, glutamatergic synaptic projections from multiple limbic and paralimbic brain regions converge to the nucleus accumbens (NAc), in which these arousing signals are processed and prioritized for behavioral output. In animal models of drug addiction, some key drug-induced alterations at NAc glutamatergic synapses underlie important cellular and circuit mechanisms that promote subsequent drug taking, seeking, and relapse. With the focus of cocaine, we review changes at NAc glutamatergic synapses that occur after different drug procedures and abstinence durations, and the behavioral impact of these changes.
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Affiliation(s)
- William J Wright
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yan Dong
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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12
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Lillis KP. TLR4 Signaling Contributes to Post-Traumatic Epileptogenesis Through Insertion of Inwardly Rectifying AMPA Receptors: Not a Happy CP-AMPAR. Epilepsy Curr 2020; 20:375-377. [PMID: 34025258 PMCID: PMC7818210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Toll-like Receptor 4 Signaling in Neurons Enhances Calcium-Permeable
α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid Receptor Currents and Drives
Post-Traumatic Epileptogenesis Korgaonkar AA, Li Y, Sekhar D, et al. Ann Neurol.
2020;87(4):497-515. doi: 10.1002/ana.25698 Objective: Traumatic brain injury is a major risk factor for acquired epilepsies, and
understanding the mechanisms underlying the early pathophysiology could yield viable
therapeutic targets. Growing evidence indicates a role for inflammatory signaling in
modifying neuronal excitability and promoting epileptogenesis. Here, we examined the
effect of innate immune receptor Toll-like receptor 4 (TLR4) on excitability of the
hippocampal dentate gyrus and epileptogenesis after brain injury. Methods: Slice and in vivo electrophysiology and western blots were conducted in rats
subject to fluid percussion brain injury or sham injury. Results: The studies identify that TLR4 signaling in neurons augments dentate granule cell
calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)
receptor (CP-AMPAR) currents after brain injury. Blocking TLR4 signaling in vivo
shortly after brain injury reduced dentate network excitability and seizure
susceptibility. When blocking of TLR4 signaling after injury was delayed; however,
this treatment failed to reduce postinjury seizure susceptibility. Furthermore, TLR4
signal blocking was less efficacious in limiting seizure susceptibility when AMPAR
currents, downstream targets of TLR4 signaling, were transiently enhanced.
Paradoxically, blocking TLR4 signaling augmented both network excitability and
seizure susceptibility in uninjured controls. Despite the differential effect on
seizure susceptibility, TLR4 antagonism suppressed cellular inflammatory responses
after injury without impacting sham controls. Interpretation: These findings demonstrate that independently of glia, the immune receptor TLR4
directly regulates post-traumatic neuronal excitability. Moreover, the
TLR4-dependent early increase in dentate excitability is causally associated with
epileptogenesis. Identification and selective targeting of the mechanisms underlying
the aberrant TLR4-mediated increase in CP-AMPAR signaling after injury may prevent
epileptogenesis after brain trauma.
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13
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Postnikova TY, Amakhin DV, Trofimova AM, Zaitsev AV. Calcium-permeable AMPA receptors are essential to the synaptic plasticity induced by epileptiform activity in rat hippocampal slices. Biochem Biophys Res Commun 2020; 529:1145-1150. [PMID: 32819578 DOI: 10.1016/j.bbrc.2020.06.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 06/24/2020] [Indexed: 10/23/2022]
Abstract
Abnormal neuronal activity during epileptic seizures alters the properties of synaptic plasticity, and, consequently, leads to cognitive impairment. The molecular mechanism of these alterations in synaptic plasticity is still unclear. In the present study, using a 4-aminopyridine (4-AP) in vitro model, we demonstrated that epileptiform activity in rat hippocampal slices initially causes substantial enhancement of field excitatory postsynaptic potential amplitude. However, the potentiation of CA3-CA1 synapses was temporary and switched to long-term depression (LTD) within an hour. Previous studies showed that transient incorporation of calcium-permeable AMPA receptors (CP-AMPARs) is crucial for the consolidation of long-term potentiation (LTP). We confirmed that, in normal conditions, the blockage of CP-AMPARs prevented the consolidation of LTP induced by theta-burst stimulation (TBS). In contrast, the blockage of CP-AMPARs preserved synaptic potentiation induced by epileptiform activity. One hour after a period of epileptiform activity in the hippocampal slices, synaptic plasticity was substantially altered, and the TBS protocol was unable to produce LTP. Moreover, if CP-AMPARs were blocked, the TBS protocol induced LTD. Our results indicate that CP-AMPARs play an essential role in the molecular mechanism of the disturbances of synaptic plasticity caused by epileptiform activity.
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Affiliation(s)
- Tatyana Y Postnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, Saint Petersburg, 194223, Russia
| | - Dmitry V Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, Saint Petersburg, 194223, Russia
| | - Alina M Trofimova
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, Saint Petersburg, 194223, Russia
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, Saint Petersburg, 194223, Russia.
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14
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Konen LM, Wright AL, Royle GA, Morris GP, Lau BK, Seow PW, Zinn R, Milham LT, Vaughan CW, Vissel B. A new mouse line with reduced GluA2 Q/R site RNA editing exhibits loss of dendritic spines, hippocampal CA1-neuron loss, learning and memory impairments and NMDA receptor-independent seizure vulnerability. Mol Brain 2020; 13:27. [PMID: 32102661 PMCID: PMC7045468 DOI: 10.1186/s13041-020-0545-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/05/2020] [Indexed: 11/18/2022] Open
Abstract
Calcium (Ca2+)-permeable AMPA receptors may, in certain circumstances, contribute to normal synaptic plasticity or to neurodegeneration. AMPA receptors are Ca2+-permeable if they lack the GluA2 subunit or if GluA2 is unedited at a single nucleic acid, known as the Q/R site. In this study, we examined mice engineered with a point mutation in the intronic editing complementary sequence (ECS) of the GluA2 gene, Gria2. Mice heterozygous for the ECS mutation (named GluA2+/ECS(G)) had a ~ 20% reduction in GluA2 RNA editing at the Q/R site. We conducted an initial phenotypic analysis of these mice, finding altered current-voltage relations (confirming expression of Ca2+-permeable AMPA receptors at the synapse). Anatomically, we observed a loss of hippocampal CA1 neurons, altered dendritic morphology and reductions in CA1 pyramidal cell spine density. Behaviourally, GluA2+/ECS(G) mice exhibited reduced motor coordination, and learning and memory impairments. Notably, the mice also exhibited both NMDA receptor-independent long-term potentiation (LTP) and vulnerability to NMDA receptor-independent seizures. These NMDA receptor-independent seizures were rescued by the Ca2+-permeable AMPA receptor antagonist IEM-1460. In summary, unedited GluA2(Q) may have the potential to drive NMDA receptor-independent processes in brain function and disease. Our study provides an initial characterisation of a new mouse model for studying the role of unedited GluA2(Q) in synaptic and dendritic spine plasticity in disorders where unedited GluA2(Q), synapse loss, neurodegeneration, behavioural impairments and/or seizures are observed, such as ischemia, seizures and epilepsy, Huntington’s disease, amyotrophic lateral sclerosis, astrocytoma, cocaine seeking behaviour and Alzheimer’s disease.
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Affiliation(s)
- Lyndsey M Konen
- Centre for Neuroscience and Regenerative Medicine (CNRM), Faculty of Science, University of Technology Sydney, PO Box 123 Broadway, Sydney, NSW, 2007, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, 2011, Australia
| | - Amanda L Wright
- Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Gordon A Royle
- Middlemore Hospital, Counties Manukau DHB, Otahuhu, Auckland, 1062, New Zealand.,The University of Auckland, Faculty of Medical and Health Sciences, School of Medicine, Grafton, Auckland, 1023, New Zealand
| | - Gary P Morris
- Centre for Neuroscience and Regenerative Medicine (CNRM), Faculty of Science, University of Technology Sydney, PO Box 123 Broadway, Sydney, NSW, 2007, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, 2011, Australia
| | - Benjamin K Lau
- Kolling Institute of Medical Research, Royal North Shore Hospital, The University of Sydney, Sydney, 2065, Australia
| | - Patrick W Seow
- Kolling Institute of Medical Research, Royal North Shore Hospital, The University of Sydney, Sydney, 2065, Australia
| | - Raphael Zinn
- Centre for Neuroscience and Regenerative Medicine (CNRM), Faculty of Science, University of Technology Sydney, PO Box 123 Broadway, Sydney, NSW, 2007, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, 2011, Australia
| | - Luke T Milham
- Centre for Neuroscience and Regenerative Medicine (CNRM), Faculty of Science, University of Technology Sydney, PO Box 123 Broadway, Sydney, NSW, 2007, Australia.,St Vincent's Centre for Applied Medical Research, Sydney, 2011, Australia
| | - Christopher W Vaughan
- Kolling Institute of Medical Research, Royal North Shore Hospital, The University of Sydney, Sydney, 2065, Australia
| | - Bryce Vissel
- Centre for Neuroscience and Regenerative Medicine (CNRM), Faculty of Science, University of Technology Sydney, PO Box 123 Broadway, Sydney, NSW, 2007, Australia. .,St Vincent's Centre for Applied Medical Research, Sydney, 2011, Australia.
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15
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Park P, Kang H, Sanderson TM, Bortolotto ZA, Georgiou J, Zhuo M, Kaang BK, Collingridge GL. On the Role of Calcium-Permeable AMPARs in Long-Term Potentiation and Synaptic Tagging in the Rodent Hippocampus. Front Synaptic Neurosci 2019; 11:4. [PMID: 30923499 PMCID: PMC6426746 DOI: 10.3389/fnsyn.2019.00004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/01/2019] [Indexed: 12/21/2022] Open
Abstract
Classically, long-term potentiation (LTP) at hippocampal CA1 synapses is triggered by the synaptic activation of NMDA receptors (NMDARs). More recently, it has been shown that calcium-permeable (CP)-AMPARs can also trigger synaptic plasticity at these synapses. Specifically, their activation is required for the PKA and protein synthesis dependent component of LTP that is typically induced by delivery of spaced trains of high frequency stimulation. Here we present new data that build upon these ideas, including the requirement for low frequency synaptic activation and NMDAR dependence. We also show that a spaced theta burst stimulation (sTBS) protocol induces a heterosynaptic potentiation of baseline responses via activation of CP-AMPARs. Finally, we present data that implicate CP-AMPARs in synaptic tagging and capture, a fundamental process that is associated with the protein synthesis-dependent component of LTP. We have studied how a sTBS can augment the level of LTP generated by a weak TBS (wTBS), delivered 30 min later to an independent input. We show that inhibition of CP-AMPARs during the sTBS eliminates, and that inhibition of CP-AMPARs during the wTBS reduces, this facilitation of LTP. These data suggest that CP-AMPARs are crucial for the protein synthesis-dependent component of LTP and its heterosynaptic nature.
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Affiliation(s)
- Pojeong Park
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Heather Kang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Thomas M Sanderson
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Zuner A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Min Zhuo
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Graham L Collingridge
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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16
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Park P, Kang H, Sanderson TM, Bortolotto ZA, Georgiou J, Zhuo M, Kaang BK, Collingridge GL. The Role of Calcium-Permeable AMPARs in Long-Term Potentiation at Principal Neurons in the Rodent Hippocampus. Front Synaptic Neurosci 2018; 10:42. [PMID: 30524263 PMCID: PMC6262052 DOI: 10.3389/fnsyn.2018.00042] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 11/05/2018] [Indexed: 11/25/2022] Open
Abstract
Long-term potentiation (LTP) at hippocampal CA1 synapses is classically triggered by the synaptic activation of NMDA receptors (NMDARs). More recently, it has been shown that calcium-permeable (CP) AMPA receptors (AMPARs) can also trigger synaptic plasticity at these synapses. Here, we review this literature with a focus on recent evidence that CP-AMPARs are critical for the induction of the protein kinase A (PKA)- and protein synthesis-dependent component of LTP.
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Affiliation(s)
- Pojeong Park
- Department of Biological Sciences and Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Heather Kang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Thomas M Sanderson
- Department of Biological Sciences and Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Zuner A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada
| | - Min Zhuo
- Department of Biological Sciences and Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Bong-Kiun Kaang
- Department of Biological Sciences and Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Graham L Collingridge
- Department of Biological Sciences and Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.,Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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17
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McGregor G, Harvey J. Regulation of Hippocampal Synaptic Function by the Metabolic Hormone, Leptin: Implications for Health and Neurodegenerative Disease. Front Cell Neurosci 2018; 12:340. [PMID: 30386207 PMCID: PMC6198461 DOI: 10.3389/fncel.2018.00340] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/13/2018] [Indexed: 11/13/2022] Open
Abstract
The role of the endocrine hormone leptin in controlling energy homeostasis in the hypothalamus are well documented. However the CNS targets for leptin are not restricted to the hypothalamus as a high density of leptin receptors are also expressed in several parts of the brain involved in higher cognitive functions including the hippocampus. Numerous studies have identified that in the hippocampus, leptin has cognitive enhancing actions as exogenous application of this hormone facilitates hippocampal-dependent learning and memory, whereas lack or insensitivity to leptin results in significant memory deficits. Leptin also markedly influences some of the main cellular changes that are involved in learning and memory including NMDA-receptor dependent synaptic plasticity and glutamate receptor trafficking. Like other metabolic hormones, there is a significant decline in neuronal sensitivity to leptin during the ageing process. Indeed, the capacity of leptin to modulate the functioning of hippocampal synapses is substantially reduced in aged compared to adult tissue. Clinical studies have also identified an association between circulating leptin levels and the risk of certain neurodegenerative disorders such as Alzheimer’s disease (AD). In view of this, targeting leptin and/or its receptor/signaling mechanisms may be an innovative approach for developing therapies to treat AD. In support of this, accumulating evidence indicates that leptin has cognitive enhancing and neuroprotective actions in various models of AD. Here we assess recent evidence that supports an important regulatory role for leptin at hippocampal CA1 synapses, and we discuss how age-related alterations in this hormonal system influences neurodegenerative disease.
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Affiliation(s)
- Gemma McGregor
- Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom
| | - Jenni Harvey
- Systems Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom
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18
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Glasgow SD, Labrecque S, Beamish IV, Aufmkolk S, Gibon J, Han D, Harris SN, Dufresne P, Wiseman PW, McKinney RA, Séguéla P, De Koninck P, Ruthazer ES, Kennedy TE. Activity-Dependent Netrin-1 Secretion Drives Synaptic Insertion of GluA1-Containing AMPA Receptors in the Hippocampus. Cell Rep 2018; 25:168-182.e6. [DOI: 10.1016/j.celrep.2018.09.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/30/2018] [Accepted: 09/06/2018] [Indexed: 11/28/2022] Open
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19
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Bie B, Wu J, Foss JF, Naguib M. Amyloid fibrils induce dysfunction of hippocampal glutamatergic silent synapses. Hippocampus 2018; 28:549-556. [PMID: 29704282 PMCID: PMC6133714 DOI: 10.1002/hipo.22955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/14/2018] [Accepted: 04/24/2018] [Indexed: 11/09/2022]
Abstract
Silent glutamatergic synapses lacking functional AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate) receptors exist in several brain regions including the hippocampus. Their involvement in the dysfunction of hippocampal glutamatergic transmission in the setting of Alzheimer's disease (AD) is unknown. This study demonstrated a decrease in the percentage of silent synapses in rats microinjected with amyloid fibrils (Aβ1-40 ) into the hippocampal CA1. Also, pairing low-frequency electric stimuli failed to induce activation of the hippocampal silent synapses in the modeled rats. Immunoblotting studies revealed a decreased expression of GluR1 subunits in the hippocampal CA1 synaptosomal preparation, indicating a potential reduction in the GluR1 subunits anchoring in postsynaptic density in the modeled rats. We also noted a decreased expression of phosphorylated cofilin, which regulates the function of actin cytoskeleton and receptor trafficking, and reduced expression of the scaffolding protein PSD95 in the hippocampal CA1 synaptosome in rats injected with Aβ1-40 . Taken together, this study illustrates dysfunction of hippocampal silent synapse in the rodent model of AD, which might result from the impairments of actin cytoskeleton and postsynaptic scaffolding proteins induced by amyloid fibrils.
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Affiliation(s)
- Bihua Bie
- Anesthesiology Institute, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, 9500 Euclid Ave. – NB3-78, Cleveland, OH 44195
| | - Jiang Wu
- Anesthesiology Institute, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, 9500 Euclid Ave. – NB3-78, Cleveland, OH 44195
| | - Joseph F. Foss
- Anesthesiology Institute, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, 9500 Euclid Ave. – NB3-78, Cleveland, OH 44195
| | - Mohamed Naguib
- Anesthesiology Institute, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, 9500 Euclid Ave. – NB3-78, Cleveland, OH 44195
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20
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Kissiwaa SA, Bagley EE. Central sensitization of the spino-parabrachial-amygdala pathway that outlasts a brief nociceptive stimulus. J Physiol 2018; 596:4457-4473. [PMID: 30004124 PMCID: PMC6138295 DOI: 10.1113/jp273976] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Chronic pain is disabling because sufferers form negative associations between pain and activities, such as work, leading to the sufferer limiting these activities. Pain information arriving in the amygdala is responsible for forming these associations and contributes to us feeling bad when we are in pain. Ongoing injuries enhance the delivery of pain information to the amygdala. If we want to understand why chronic pain can continue without ongoing injury, it is important to know whether this facilitation continues once the injury has healed. In the present study, we show that a 2 min noxious heat stimulus, without ongoing injury, is able to enhance delivery of pain information to the amygdala for 3 days. If the noxious heat stimulus is repeated, this enhancement persists even longer. These changes may prime this information pathway so that subsequent injuries may feel even worse and the associative learning that results in pain-related avoidance may be promoted. ABSTRACT Pain is an important defence against dangers in our environment; however, some clinical conditions produce pain that outlasts this useful role and persists even after the injury has healed. The experience of pain consists of somatosensory elements of intensity and location, negative emotional/aversive feelings and subsequent restrictions on lifestyle as a result of a learned association between certain activities and pain. The amygdala contributes negative emotional value to nociceptive sensory information and forms the association between an aversive response and the environment in which it occurs. It is able to form this association because it receives nociceptive information via the spino-parabrachio-amygdaloid pathway and polymodal sensory information via cortical and thalamic inputs. Synaptic plasticity occurs at the parabrachial-amygdala synapse and other brain regions in chronic pain conditions with ongoing injury; however, very little is known about how plasticity occurs in conditions with no ongoing injury. Using immunohistochemistry, electrophysiology and behavioural assays, we show that a brief nociceptive stimulus with no ongoing injury is able to produce long-lasting synaptic plasticity at the rat parabrachial-amygdala synapse. We show that this plasticity is caused by an increase in postsynaptic AMPA receptors with a transient change in the AMPA receptor subunit, similar to long-term potentiation. Furthermore, this synaptic potentiation primes the synapse so that a subsequent noxious stimulus causes prolonged potentiation of the nociceptive information flow into the amygdala. As a result, a second injury could have an increased negative emotional value and promote associative learning that results in pain-related avoidance.
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Affiliation(s)
- Sarah A Kissiwaa
- Discipline of Pharmacology and Charles Perkins CentreUniversity of SydneySydneyNSW2006Australia
| | - Elena E Bagley
- Discipline of Pharmacology and Charles Perkins CentreUniversity of SydneySydneyNSW2006Australia
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21
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McGregor G, Harvey J. Food for thought: Leptin regulation of hippocampal function and its role in Alzheimer's disease. Neuropharmacology 2017; 136:298-306. [PMID: 28987937 DOI: 10.1016/j.neuropharm.2017.09.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/27/2017] [Accepted: 09/30/2017] [Indexed: 01/08/2023]
Abstract
Accumulating evidence indicates that diet and body weight are important factors associated with Alzheimer's disease (AD), with a significant increase in AD risk linked to mid-life obesity, and weight loss frequently occurring in the early stages of AD. This has fuelled interest in the hormone leptin, as it is an important hypothalamic regulator of food intake and body weight, but leptin also markedly influences the functioning of the hippocampus; a key brain region that degenerates in AD. Increasing evidence indicates that leptin has cognitive enhancing properties as it facilitates the cellular events that underlie hippocampal-dependent learning and memory. However, significant reductions in leptin's capacity to regulate hippocampal synaptic function occurs with age and dysfunctions in the leptin system are associated with an increased risk of AD. Moreover, leptin is a potential novel target in AD as leptin treatment has beneficial effects in various models of AD. Here we summarise recent advances in leptin neurobiology with particular focus on regulation of hippocampal synaptic function by leptin and the implications of this for neurodegenerative disorders like AD. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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Affiliation(s)
- Gemma McGregor
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - Jenni Harvey
- Division of Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom.
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22
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Pick JE, Khatri L, Sathler MF, Ziff EB. mGluR long-term depression regulates GluA2 association with COPII vesicles and exit from the endoplasmic reticulum. EMBO J 2016; 36:232-244. [PMID: 27856517 DOI: 10.15252/embj.201694526] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 10/09/2016] [Accepted: 10/11/2016] [Indexed: 01/05/2023] Open
Abstract
mGluR long-term depression (mGluR-LTD) is a form of synaptic plasticity induced at excitatory synapses by metabotropic glutamate receptors (mGluRs). mGluR-LTD reduces synaptic strength and is relevant to learning and memory, autism, and sensitization to cocaine; however, the mechanism is not known. Here we show that activation of Group I mGluRs in medium spiny neurons induces trafficking of GluA2 from the endoplasmic reticulum (ER) to the synapse by enhancing GluA2 binding to essential COPII vesicle proteins, Sec23 and Sec13. GluA2 exit from the ER further depends on IP3 and Ryanodine receptor-controlled Ca2+ release as well as active translation. Synaptic insertion of GluA2 is coupled to removal of high-conducting Ca2+-permeable AMPA receptors from synapses, resulting in synaptic depression. This work demonstrates a novel mechanism in which mGluR signals release AMPA receptors rapidly from the ER and couple ER release to GluA2 synaptic insertion and GluA1 removal.
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Affiliation(s)
- Joseph E Pick
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA
| | - Latika Khatri
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA
| | - Matheus F Sathler
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA.,Department of Pharmacology and Physiology, Fluminense Federal University, Niteroi, Brazil
| | - Edward B Ziff
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA
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23
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Liu MG, Li HS, Li WG, Wu YJ, Deng SN, Huang C, Maximyuk O, Sukach V, Krishtal O, Zhu MX, Xu TL. Acid-sensing ion channel 1a contributes to hippocampal LTP inducibility through multiple mechanisms. Sci Rep 2016; 6:23350. [PMID: 26996240 PMCID: PMC4800407 DOI: 10.1038/srep23350] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/02/2016] [Indexed: 12/30/2022] Open
Abstract
The exact roles of acid-sensing ion channels (ASICs) in synaptic plasticity remain elusive. Here, we address the contribution of ASIC1a to five forms of synaptic plasticity in the mouse hippocampus using an in vitro multi-electrode array recording system. We found that genetic deletion or pharmacological blockade of ASIC1a greatly reduced, but did not fully abolish, the probability of long-term potentiation (LTP) induction by either single or repeated high frequency stimulation or theta burst stimulation in the CA1 region. However, these treatments did not affect hippocampal long-term depression induced by low frequency electrical stimulation or (RS)-3,5-dihydroxyphenylglycine. We also show that ASIC1a exerts its action in hippocampal LTP through multiple mechanisms that include but are not limited to augmentation of NMDA receptor function. Taken together, these results reveal new insights into the role of ASIC1a in hippocampal synaptic plasticity and the underlying mechanisms. This unbiased study also demonstrates a novel and objective way to assay synaptic plasticity mechanisms in the brain.
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Affiliation(s)
- Ming-Gang Liu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Hu-Song Li
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Guang Li
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Department of Developmental and Behavioral Pediatrics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200129, China
| | - Yan-Jiao Wu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Shi-Ning Deng
- Department of Developmental and Behavioral Pediatrics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai 200129, China
| | - Chen Huang
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Oleksandr Maximyuk
- Bogomoletz Institute of Physiology of NAS Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine.,State Key Laboratory for Molecular and Cellular Biology, 4 Bogomoletz Str., 01024 Kyiv, Ukraine
| | - Volodymyr Sukach
- Bogomoletz Institute of Physiology of NAS Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine.,State Key Laboratory for Molecular and Cellular Biology, 4 Bogomoletz Str., 01024 Kyiv, Ukraine
| | - Oleg Krishtal
- Bogomoletz Institute of Physiology of NAS Ukraine, 4 Bogomoletz Str., 01024 Kyiv, Ukraine.,State Key Laboratory for Molecular and Cellular Biology, 4 Bogomoletz Str., 01024 Kyiv, Ukraine
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, TX 77030, USA
| | - Tian-Le Xu
- Discipline of Neuroscience and Department of Anatomy, Histology and Embryology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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24
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Quintana P, Soto D, Poirot O, Zonouzi M, Kellenberger S, Muller D, Chrast R, Cull-Candy SG. Acid-sensing ion channel 1a drives AMPA receptor plasticity following ischaemia and acidosis in hippocampal CA1 neurons. J Physiol 2015; 593:4373-86. [PMID: 26174503 PMCID: PMC4594240 DOI: 10.1113/jp270701] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 07/08/2015] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The hippocampal CA1 region is highly vulnerable to ischaemic stroke. Two forms of AMPA receptor (AMPAR) plasticity - an anoxic form of long-term potentiation and a delayed increase in Ca(2+) -permeable (CP) AMPARs - contribute to this susceptibility by increasing excitotoxicity. In CA1, the acid-sensing ion channel 1a (ASIC1a) is known to facilitate LTP and contribute to ischaemic acidotoxicity. We have examined the role of ASIC1a in AMPAR ischaemic plasticity in organotypic hippocampal slice cultures exposed to oxygen glucose deprivation (a model of ischaemic stroke), and in hippocampal pyramidal neuron cultures exposed to acidosis. We find that ASIC1a activation promotes both forms of AMPAR plasticity and that neuroprotection, by inhibiting ASIC1a, circumvents any further benefit of blocking CP-AMPARs. Our observations establish a new interaction between acidotoxicity and excitotoxicity, and provide insight into the role of ASIC1a and CP-AMPARs in neurodegeneration. Specifically, we propose that ASIC1a activation drives certain post-ischaemic forms of CP-AMPAR plasticity. ABSTRACT The CA1 region of the hippocampus is particularly vulnerable to ischaemic damage. While NMDA receptors play a major role in excitotoxicity, it is thought to be exacerbated in this region by two forms of post-ischaemic AMPA receptor (AMPAR) plasticity - namely, anoxic long-term potentiation (a-LTP), and a delayed increase in the prevalence of Ca(2+) -permeable GluA2-lacking AMPARs (CP-AMPARs). The acid-sensing ion channel 1a (ASIC1a), which is expressed in CA1 pyramidal neurons, is also known to contribute to post-ischaemic neuronal death and to physiologically induced LTP. This raises the question does ASIC1a activation drive the post-ischaemic forms of AMPAR plasticity in CA1 pyramidal neurons? We have tested this by examining organotypic hippocampal slice cultures (OHSCs) exposed to oxygen glucose deprivation (OGD), and dissociated cultures of hippocampal pyramidal neurons (HPNs) exposed to low pH (acidosis). We find that both a-LTP and the delayed increase in the prevalence of CP-AMPARs are dependent on ASIC1a activation during ischaemia. Indeed, acidosis alone is sufficient to induce the increase in CP-AMPARs. We also find that inhibition of ASIC1a channels circumvents any potential neuroprotective benefit arising from block of CP-AMPARs. By demonstrating that ASIC1a activation contributes to post-ischaemic AMPAR plasticity, our results identify a functional interaction between acidotoxicity and excitotoxicity in hippocampal CA1 cells, and provide insight into the role of ASIC1a and CP-AMPARs as potential drug targets for neuroprotection. We thus propose that ASIC1a activation can drive certain forms of CP-AMPAR plasticity, and that inhibiting ASIC1a affords neuroprotection.
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Affiliation(s)
- Patrice Quintana
- Department of Basic Neurosciences, University of Geneva, 1211 Geneva 4, Switzerland.,Department of Medical Genetics, University of Lausanne, 1005, Lausanne, Switzerland
| | - David Soto
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Olivier Poirot
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, WC1E 6BT, UK.,Department of Pharmacology and Toxicology, University of Lausanne, 1005, Lausanne, Switzerland.,Department of Medical Genetics, University of Lausanne, 1005, Lausanne, Switzerland
| | - Marzieh Zonouzi
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Stephan Kellenberger
- Department of Pharmacology and Toxicology, University of Lausanne, 1005, Lausanne, Switzerland
| | - Dominique Muller
- Department of Basic Neurosciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - Roman Chrast
- Department of Medical Genetics, University of Lausanne, 1005, Lausanne, Switzerland
| | - Stuart G Cull-Candy
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
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25
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Arendt KL, Zhang Y, Jurado S, Malenka RC, Südhof TC, Chen L. Retinoic Acid and LTP Recruit Postsynaptic AMPA Receptors Using Distinct SNARE-Dependent Mechanisms. Neuron 2015; 86:442-56. [PMID: 25843403 DOI: 10.1016/j.neuron.2015.03.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/06/2015] [Accepted: 02/26/2015] [Indexed: 11/28/2022]
Abstract
Retinoic acid (RA)-dependent homeostatic plasticity and NMDA receptor-dependent long-term potentiation (LTP), a form of Hebbian plasticity, both enhance synaptic strength by increasing the abundance of postsynaptic AMPA receptors (AMPARs). However, it is unclear whether the molecular mechanisms mediating AMPAR trafficking during homeostatic and Hebbian plasticity differ, and it is unknown how RA signaling impacts Hebbian plasticity. Here, we show that RA increases postsynaptic AMPAR abundance using an activity-dependent mechanism that requires a unique SNARE (soluble NSF-attachment protein receptor)-dependent fusion machinery different from that mediating LTP. Specifically, RA-induced AMPAR trafficking did not involve complexin, which activates SNARE complexes containing syntaxin-1 or -3, but not complexes containing syntaxin-4, whereas LTP required complexin. Moreover, RA-induced AMPAR trafficking utilized the Q-SNARE syntaxin-4, whereas LTP utilized syntaxin-3; both additionally required the Q-SNARE SNAP-47 and the R-SNARE synatobrevin-2. Finally, acute RA treatment blocked subsequent LTP expression, probably by increasing AMPAR trafficking. Thus, RA-induced homeostatic plasticity involves a novel, activity-dependent postsynaptic AMPAR-trafficking pathway mediated by a unique SNARE-dependent fusion machinery.
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Affiliation(s)
- Kristin L Arendt
- Department of Neurosurgery, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Yingsha Zhang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Sandra Jurado
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Robert C Malenka
- Nancy Pritzker Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA
| | - Lu Chen
- Department of Neurosurgery, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305-5453, USA.
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26
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Combs-Bachmann RE, Johnson JN, Vytla D, Hussey AM, Kilfoil ML, Chambers JJ. Ligand-directed delivery of fluorophores to track native calcium-permeable AMPA receptors in neuronal cultures. J Neurochem 2015; 133:320-9. [PMID: 25640258 DOI: 10.1111/jnc.13051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/01/2022]
Abstract
Subcellular trafficking of neuronal receptors is known to play a key role in synaptic development, homeostasis, and plasticity. We have developed a ligand-targeted and photo-cleavable probe for delivering a synthetic fluorophore to AMPA receptors natively expressed in neurons. After a receptor is bound to the ligand portion of the probe molecule, a proteinaceous nucleophile reacts with an electrophile on the probe, covalently bonding the two species. The ligand may then be removed by photolysis, returning the receptor to its non-liganded state while leaving intact the new covalent bond between the receptor and the fluorophore. This strategy was used to label polyamine-sensitive receptors, including calcium-permeable AMPA receptors, in live hippocampal neurons from rats. Here, we describe experiments where we examined specificity, competition, and concentration on labeling efficacy as well as quantified receptor trafficking. Pharmacological competition during the labeling step with either a competitive or non-competitive glutamate receptor antagonist prevented the majority of labeling observed without a blocker. In other experiments, labeled receptors were observed to alter their locations and we were able to track and quantify their movements. We used a small molecule, ligand-directed probe to deliver synthetic fluorophores to endogenously expressed glutamate receptors for the purpose of tracking these receptors on live, hippocampal neurons. We found that clusters of receptors appear to move at similar rates to previous studies. We also found that the polyamine toxin pharmacophore likely binds to receptors in addition to calcium-permeable AMPA receptors.
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27
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Bliss TVP, Collingridge GL, Morris RGM. Synaptic plasticity in health and disease: introduction and overview. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130129. [PMID: 24298133 DOI: 10.1098/rstb.2013.0129] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We summarize the reviews and research papers submitted by speakers at a discussion meeting on Synaptic Plasticity in Health and Disease held at the Royal Society, London on 2-3 December 2013, and a subsequent satellite meeting convened at the Royal Society/Kavli Centre at Chicheley Hall on 4-5 December 2013. Together, these contributions give an overview of current research and controversies in a vibrant branch of neuroscience with important implications for the understanding of many forms of learning and memory, and a wide spectrum of neurological and cognitive disorders.
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Affiliation(s)
- T V P Bliss
- Division of Neurophysiology, MRC National Institute for Medical Research, , London NW7 1AA, UK
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